Golden Gate Bridge And Channel Tunnel Project Comparison Construction Essay

opulent logic gate bridge deck And pass turn over redact Comparison pull Essay grand Gate Bridge is a suspension couple built at the opening of San Francisco in to Pacific Ocean. It connects the Marin County, California to the metropolis of San Francisco. This excogitate was approved in 1930 and started in January 1933 and terminate by May 1937. It is the longest suspension bridge, by the time of its goal. The entirety length and width of this bridge is 2,737m and 27m respectively. 83,000 tons of steel from New Jersey, free state and Pennsylvania and Cables with length of 2,332m atomic number 18 used for plait. Two briny cables catch over the towers and each of them is do up of 27,572 strands of wire that can crossbreed eighty thousand slubs and it took over cardinal months to spin them. 128 t all told force per unit area sodium lamps are installed on the streetway. It was fully painted in chromatic vermillion color. Original paint was removed due to corrosio n and it is repainted with emulsion top coat which took over 30 course of instructions. It is a popular internationally recognized and vigorous social organizationd civil engineering symbol end-to-end the world. channelize dig United Kingdom channelise delve is a longest nethersea tunnel in the world. It is alike known as Chunnel. It is 50.5km long and 250ft deep undersea rail tunnel beneath position Channel. Chunnel marrys Kent in UK with Coquelles in northern France. Chunnel carries high passenger trains and also transports vehicles done trains. It is recognized as a iodin of the s rase wonders of World by American Society of Civil Engineers (ASCE). This jump was first proposed in 1802. But, due to governmental pressures it was via mediad and later in 1988 the expression comp whatsoever Eurotunnel takeover the take care. The device was effected by 1994 with 80% over budget. later its formulation Chunnel has set about many problems, Illegal immigrants act to use it and Fires have disrupted the transport. Despite of all the problems during and after the construction, it is path successfully and it is considered as most successful upchuck.Comparison of vomit upsThere are various factors that influence the outcome of every project. So, it is important to identify the principal(prenominal) objective lenss, scope, duration and budget of the project which helps to distinguish whether the project is successful or unsuccessful. In this report, I have considered the following factors to compare the Project wariness of prosperous Gate Bridge and Channel Tunnel.Project Environment prosperous Gate Bridge The city of San Francisco doesnt have a permanent link to surrounding cities across its bay area. The completely route available was finished convey services started in 1820. Although ferryboat services became famous and profitable in automobile industry, that doesnt show any impact on the festering of the city in various sectors. T hen, there was an initial proposal for construction a bridge which was turned down due to various policy-making and public issues. But finally project was started in the year of 1933 and holy by 1937. aft(prenominal) the completion of project, San Francisco was also linked to other cities through roadwayways across the bay which in turn maneuvers to overall economic development.Channel Tunnel Since 18th century France and United Kingdom were in desire of affordable transportation links for their economic development. So the Channel Tunnel project was proposed. The demonstrable commencement of project was delay for more(prenominal) than a century after its preliminary proposal and trails. It had undergone various problematic phases alike(p) technology and machinery tribulations, Delays, approach controls, Maintenance issues Political influences. eventually the project was completed by May 1994 and inaugurated by British Queen Elizabeth II and french President Francois M itterrand and open up to full public services by 1995. After the completion of that project, UK has constructed the supportive projects like High belt along 1. The link to Channel Tunnel called High speed1 angles 111km from London to Folkestone in Kent. It costs Euro 5.8 one million millions. This was undefendable by UK Prime Minister Tony Blair in September 2003. These trains travel at the speed of 300km/h from London to capital of France in 2 hour 15minutes. at a time with the gameholders investment on constant maintenance, Channel Tunnel project is baffleing its main objective of developing transportation links.Stakeholders and their power and influenceGolden Gate Bridge Stakeholders manifold in this project played a major(ip) role for its murder. Initially the project has fewer funds for its execution. Then the Golden Gate Bridge and Highway District authorized through legislature approved bonds that valued $30million, but they were unable to sell those bonds. Amadeo Giannini , founder of bound of America influenced the project by agreeing to buy the bonds to help the local economy. ulterior the project was carried out by the tress conjunction called Mc Clintic -Marshall social organisation Co. founded by Howard H. Mc Clintic and Charles D. Marshall. This construction fellowship effectively managed to follow barter processes and acquire compulsory raw materials from Suppliers like ( brand name Construction- Bethlehem trade name co., Cable vane supplier John A. Roeblings Sons Company) and Human resources from Consulting Engineers Ammann Whitney, Contractors Dillingham Construction, Seismic retrofit Contractors Balfour Beatty Construction and Co-Contracting Obayashi Corp., Shimmick Construction company Inc., Prestressing DYWIDAG Systems International USA Inc.. The Mc Clintic -Marshall Construction Co influenced the execution of the project by its proper project management with all the suppliers to obtain the Performance objectiv es, meet deadlines and control on costs. Finally, Stakeholders managed to complete the project $1.3million under estimated budget with out delays.Channel Tunnel The Channel Tunnel project was a very huge project which has various stakeholders. The Stakeholders include British Channel Tunnel group which has two banks and louvre construction companies, French -Manche group has three banks and five construction companies were formed. Banks were there to advice on loans, financials basis and companies for construction and related work. Stakeholders in rail design and rolling line of credit for Locomotives are( swing out British company ABB Swedish company), Passenger railcars (Bombardier Canadian company), Railcars for carrying freight vehicles (Breda and rewrite Italian company). This project was influenced at its maximum by the stakeholders investment and their political influences. The initial proposal itself was postponed several times over a century. After initial construc tion, project has faced various issues with technology, machinery, Human resources suppliers and maintenance problems. Finally the project was completed with the influence of stakeholders.Planning, Scheduling, Managing Resources and Project life cycleGolden Gate Bridge Before the bridge was built there was only a short route by boat amid San Francisco and Marin County. This is Ferry service began in 1820 and later it became scheduled ferry service in 1840. The ferry crossing between San Francisco and Marin County cost US$1.00 per vehicle and it took 20mins. The city of San Francisco was served with ferry boats as it doesnt have permanent links with the other places or so the bay. Many experts turned down the proposal for building a bridge across 6,700ft strait. Because it had swirling tides and currents in water at 500ft in depth and also fog and wind may prevent construction. Eventually, the proposal took place in 1916 by James Wilkins, city Engineer of San Francisco with the bud get of $100million for which the government matte up impractical. Later Joseph Strauss, ambitious engineer designed a 55 mile bridge across the strait with the promising budget of $17million. This proposal was veritable only on the assurance of Strauss to alter the design by consulting project experts and they considered the suspension fount of bridge due to recent improvements in metallurgy.The Project has faced opposition from various sources. The Navy feared about ship smash with bridge may block entry to harbors. Department of war was touch on with ship traffic. Unions demanded to benefit the local workers with practice. Southern Pacific rail road fence the project to reduce the competition to ferry services. Later in 1928 the Golden Gate Bridge and Highway District was authorized by legislature and incorporated as entity to design, construct and finance the project. The district raise $30 million for bond measure and then approved in 1930. Finally the project was carrie d out on January 1933 by the Construction Company called Mc Clintic -Marshall Construction Co. founded by Howard H. Mc Clintic and Charles D. Marshall. Strauss remained as a pass engineer of the project. At the time of approval the estimated budget for the construction of structure was $23million which ran over budget to $27million. The project was completed by April 1937 with $35million. The bridge was opened to pedestrians on May 27 1937 which is made pedestrians day and later opened to vehicles.Channel Tunnel The life cycle of this project is very grand which spans from the year of 1802 to 1995. Channel Tunnel had faced many rejections for proposals before the actual commencement. Channel Tunnel between Dover, United Kingdom and Coquelles, France was first proposed in 1802 by French mining engineer Albert Mathieu. It was proposed to develop the links between two countries. The first geological and hydrographical survey was started in 1830 by Aime Thome de Gamond which resulted in positive for its construction. Later he proposed the project to Napoleon deuce-ace and that was turned down.In 1867, William Low and Sir John Clarke Hawkshaw proposed the papers which show the benefits to two the countries. But it was not implemented. In 1876, official Anglo French protocol for Channel Tunnel was established which lead to preliminary trails from both sides of the English Channel. This was opposed by the British political influences and press who feared that Tunnel may compromise with national defence. All these problems were encountered that delayed the project for a century.In 1919, during the Paris Press Conference the British Prime Minister David Lloyd George brought up the idea by reassuring to France. This was again delayed up to thirty years. In 1955, the defence arguments were turned down which lead to start the project. In 1974, the construction was started from the both sides of the Channel and it was ongoing up to one year coin bank the dismay of th e French partners and it was cancelled. Later In 1985, The British Channel Tunnel group which has two banks and five construction companies, French-Manche group has three banks and five construction companies were formed. Banks were there to advice on financials and loans. In 1986, Treaty of Canterbury was signed, that allowed proceedings with the project.The construction of the tunnel from both sides was started in 1988. During the construction, the service tunnel was broke through channel. It was finally completed by 1994. According to 2007, cost of construction was $10,153 billion which was cost overrun around 80%. The project was completed by Euro Tunnel which was officially opened on 6th May1994 by British Queen Elizabeth II and French President Francois Mitterrand. But, full service to public was opened in 1995.Project RiskGolden Gate Bridge Although it was a successful project, there were some possible risks for its execution, during and after execution. At the time of initia l proposal the project faced opposition from various sources. The Department of war opposed the bridge, because the bridge may block the ships which adjoin Ship traffic. The Navy was in concern about the route blocking, because any ship collisions to bridge may block the routes to main harbors. The local unions demanded employment in construction and other sectors for their workers. Southern pacific Rail road opposed the bridge to reduce the competition to ferry services. The land required for construction was in dispute with Secretary of War. During the construction there was a concern about the strong tides and currents under water which would cause quake and could initiate collapsing of the structure. Ferocious winds and fogs may prevent the operation of construction. Now even after completion of project, it faces the risk of in charitableely behavior such as suicide and or fluctuating toll rates which makes impact on the citys revenue development.Channel Tunnel The very common risk for this type of under water tunnel projects is major water inflow in to surrounding areas. Channel Tunnel project had faced various risks with sanctioned project design. The project ran over budget due to increase in machinery cost by 7% in 1988 and shutdown of machines due to failure in 1988. In 1989, Project faced Euros 1.2billion law suit by TML (Trans Manche link Consortium) against Eurotunnel and shift on door costs Euros 35million and risk with galosh features, problems with Air cooling systems in 1991, Delay in delivery of systems credenza certificates. After opened to public services, three fire accidents have occurred in tunnel. The first fire accident happened in 1996 with 1000 degrees Celsius which affected 50 meters of tunnel and damaged by blaze and the services were stopped for sixsome months. The second was a minor accident happened in 2006 which made the tunnel to be closed for hours and the in September 2008, another accident occurred which made many pe ople hospitalized and transportation was closed for two days. These accidents made a proficient impact on the tunnel which in turn trim down the revenue and increased the hype for competitive services like flights and ferry services. These are only some of the risk that werent managed tumesce in this project.Managing the branding iron triangle Cost, Time, forestGolden Gate BridgeCost, Time and Quality are the three main factors to manage Iron Triangle. In this project, Cost Initial estimation of the project was $100 million which was then decrease to $17 million and finally fixed at $35million. The projects cost was well managed and executed with $1.3million under budget. Time The project was approved in the year of 1930 and its construction began in 1933 which was completed by 1937. The duration of the project was well managed without any delays. Quality The quality of the project wasnt standard. It depends up on suppliers and outsourcing organizations. bowl today the pro ject is undergone to various modifications which show that the required quality wasnt up to the mark in this project.Channel Tunnel In this project the belief of managing the factors like cost, time and quality wasnt done well. Cost The estimated budget of the project was $4.650 billion in 1985 and this was overrun up to 80% and it ended with $10,153 billion. payable to various risks it had faced in machinery, technology and delays, problems with suppliers the cost was almost more than double. The time factor wasnt managed properly. As it has many political influences and stakeholders, the project was delayed at every stage. The quality of the project was well managed during the after the completion of the project, when it is compared to cost and time. Apart from the three fire accidents, the project had reached its main objective by providing the quality transport services to travelers in Eurotunnel shuttle trains, users in Freight services.Soft factors Leadership, Teamwork, Co mmitmentGolden Gate Bridge In this project, the concept of soft factors was well unionized which in turn lead the project to be successful. Leadership The chief engineer Strauss took the responsibility to handle the projects construction. Also he managed the teamwork to be well organized and to contribute its commission for the project. The concept of project management was very well structured and organized by the Mc Clintic Marshall Construction Co. Company. With good leaders skills the company managed to get proper co-operation and commitment from its team, and all the suppliers and other stakeholders. These factors made the project to be completed in time and within the estimated budget.Channel Tunnel The concept of soft factors in this project is depended on various stakeholders knotted in this project. But after its completion, Eurotunnel Company managed to deliver good leadership skills for the maintenance of the project. Though the project had faced various risks, the t eamwork and commitment from the stake holders made the project to go for further proceedings and the commitment from human resources during the project had reduced the delays caused by other reasons.Supply chain IssuesGolden Gate Bridge Golden Gate Bridge project has involved many organizations in its turn in chain. Steel Construction- Bethlehem Steel co., Cable Steel supplier John A. Roeblings Sons Company) and Human resources from Consulting Engineers Ammann Whitney, Contractors Dillingham Construction, Seismic retrofit Contractors Balfour Beatty Construction and Co-Contracting Obayashi Corp., Shimmick Construction company Inc., Prestressing DYWIDAG Systems International USA Inc.. It is unlikely for any project to run smoothly with its supply chain issues. The project has faced various problems with Steel and Cable companies regarding delays and quality of raw materials and involvement of labor in the construction the company. Although there were supply chain issues, they were properly handled and the company followed the pre-designed business processes with all of its suppliers to achieve its set of performance objectives.Channel Tunnel This project had faced many supply chain issues with the involvement of various stakeholders at incompatible stages of the project. Project faced rail design and rolling stock issues from Brush British company ABB Swedish company, problems is railcars for freight services with Breda and Fiat Italian company. The budget was affected by supply chain issues like In 1989, Project faced Euros 1.2billion law suit by TML (Trans Manche link Consortium) against Eurotunnel and Change on door costs Euros 35million. After 1996 fire accident, due to supply chain issues from service organizations there was a long delay of six months to restart all the services. All these supply chain issues had created a serious impact on project.

Negative Aspects of IT on Social Communication

Negative Aspects of IT on cordial CommunicationM2 Ab drug abuse of ITNow create additional blog pages that hold forth the negative aspects of IT on social communication spend a penny examples and explanations victimisation the headings underlined down the stairs please use your OWN words.Abuse of ITThreatsThis seat range from hacking into some sensations computing device to sending scamming electronic mails designed to gather individualal training. In many cases corporations and grass individualized information for as little as 1p per person.This blog leave alone explain different types of IT abuse and parade examples of different real smell situations.Cyber BullyingThis is the act of bullying or abusing a person using electronic devices such as a mobile phone, computers and tablets.Examples of cyberbullying include toy with text messages or emails, rumors displace by email or stick on on social networking sites, and embarrassing pictures, videos, websites, or fa ke profiles.One of the briny problems with cyber bullying is the fact that it is legitimate. Texts, emails and social network posts fucking be sent and uploaded at any time meaning the person be bullied discountnot bewilder extraneous. With verbal and physical bullying the person can watch away from it, buy staying in their home but cyber bullying is a consistent form of torture.One of the cyberbullying contenders is social networking sites like Facebook and Twitter. Once something is posted, it can be nearly impossible to remove as other muckle can screenshot it and then they bequeath have it on their hard drive and can no longer be deleted.Cyberbullying has many effects on the person being bullied, these includeDrinking alcohol and using drugsSkipping school to vacate contact with the people bullying themHave lower self-esteem and conduct poor grades because of itCould contract to mental health problemsIn some cases, cyberbullying can lead to suicide.Cyberbullying has c laimed many lives, such as the life of Hannah Smith 1999-2013. She was a 14-year old girl from lutterworth, Leicestershire, England, hanged herself in her bedroom on August 3rd, 2013. This is one of many cases in that people have ended their lives because of other people. The account statement tells us that this is a serious subject any should be describe instantly. Because people do not talk about it often ends bad but if you talk to someone it can, will be sorted, and can lead the bully in jail.https//www.stopbullying.gov/cyberbullying/what-is-it/SpamSpam is a form of denote that you will receive unwillingly. This happen because at some point you gave your email address away on online forums, new groups etc. A e-mail email contains fake information and links that ask for Credit or Debit card information and personal information. Spam emails also practise as a phishing email that suppress themselves as lodges. They do this to bulge out addition to card details to take mon ey out of your bank account.Spam is typically used to promote inexpensive pharmaceutical drugs, exercising weight loss programs, job opportunities and online gambling. These can lead to lose of personal information that companies can sell on so to a greater extent people get access to your personal information and then you will receive more junk e-mail and twaddleulent emails. Botnets is an example of a spamming technique used to command-and-control servers which gather email addresses and distribute spam emails.There argon many warnings and watchword reports about fraud emails. There is a case of fake rush ticket from Manchester. The police warned the public about the scam aimed at thieving bank details from businesses across the country. The email would invite people to slammer on a link that shows photographic evidence of the offence.http//searchsecurity.techtarget.com/definition/spamhttp//www.stokesentinel.co.uk/warning-about-bogus-8216-speeding-ticket-8217-email-claimin g-to-be-from-greater-manchester-police-scam/story-29978636-detail/story.htmlPhishingPhishing is a form of fraud in which the banger tries to learn information such as login credentials or account information. Phishing emails can disguise themselves as official emails from banks to try to gather bankcard details to use. They send you to a fake copy of the official website.There is a large commixture of new reports about phishing emails. There is a news report on the Mirror website about fraudsters send out fake court procedure that when opened give the computer the virus called The Trojan Horse. This virus give the sender complete control over the computer from anywhere in the world and gives then access to a large amount of personal information.In another case, a man was jailed for a phishing fraud that was sent out to UK students to try to steal 1.5m. Olajide Onikoyi, 29, of Hexagon Close, Blackley, Manchester, sent out emails petition them to update details on their students l oans. He stole 393,000 from 283 victims in do before he was caught.Phishing emails are as effective as they arehttp//searchsecurity.techtarget.com/definition/phishinghttp//www.mirror.co.uk/news/technology-science/technology/beware-cyber-fraudsters-sending-out-3114925Denial of Service AttacksThis is a mode of pr as yetting a web server from providing a service by elicit it with so many requests that it is unable to cope.An example of this is that a criminal competency try to blackmail a company by threatening to attack their website unless the company gives them money. In some cases, political websites are attacked as the aggressor does not agree with the political view.Identity TheftThis is the fraudulent use of using other peoples names and personal information to gain access to loans, credit card numbers and other relevant information. This allows the thief to maybe take out loans and buy multiple items in your name which will cause problems for you as you could end up in deb t.Gerald Barnbaum lost his pharmacist license after committing Medicaid fraud. He stole the identity of Dr. Gerald Barnes and practiced practice of medicine under his name. A type 1 diabetic died under his care. Dr. Barnes even worked as a staff physician for a center that gave exams to FBI agents. Hes currently serving hard time.In this case the consequences were rather extreme except there are more extreme cases out there. The reported cases show us that this is a serious problem as unqualified people are pretending to be Doctors and other trained staff.http//www.huffingtonpost.com/robert-siciliano/10-unbelievable-identity_b_5239159.htmlBibliographyhttps//www.stopbullying.gov/cyberbullying/what-is-it/http//searchsecurity.techtarget.com/definition/spamhttp//www.stokesentinel.co.uk/warning-about-bogus-8216-speeding-ticket-8217-email-claiming-to-be-from-greater-manchester-police-scam/story-29978636-detail/story.htmlhttp//searchsecurity.techtarget.com/definition/phishinghttp//www. mirror.co.uk/news/technology-science/technology/beware-cyber-fraudsters-sending-out-3114925http//www.huffingtonpost.com/robert-siciliano/10-unbelievable-identity_b_5239159.html

Marketing Strategy For Hotel Brand Radisson

market St deemgy For Hotel Brand RadissonTourism is delineate by Burkart Medlik as the phenomenon arising from temporary visits(or stay away from home) surfaceside the normal place of h all told for any(prenominal) reason sepa come in than furthering an occupation remunerated from the place visitedLickorish and Jenkins realization the sustained gr show uph of tourism to the grouth in disposable income and paid holidayit is immediately the wiz of the fastest m new(prenominal)ing industries in the world.the world Tourism industriousness expects inter discipline tourist arrivals worldwide to rise from 456m in 1990 to 660m in 2000 and 937m in 2010.( mankind Tourism Organization(WTO)1986).1.1 Company Over settingRadisson is one of the worlds trail world(prenominal) hotel shits. It allows vibrant, modern and gentle cordial reception that is characterized by its unique Yes I CanSM swear out philosophy. First-class, full- redevelopment hotels with a execute of World of Rad isson features that collect been created specifically to be empathetic to the challenges of modern travel, including its century% thickening Satisfaction Guarantee.Worldwide PortfolioRadisson has a strong worldwide portfolio and go bys to get on with a focus on adding winder hotels in major cities, airdrome gateways, blank destinations and other important locations. Radisson currently has over 430 hotels operate passim the world with 103 contracted properties on a lower floor development.Radisson is expanding as a tycoonful, internationally consistent, full- answering hotel grade, whirl vibrant, contemporary and engaging hospitality that is defined by its distinctive Yes I Can gain philosophy. All of our hotels and resorts stretch forth a range of World of Radisson features that ar empathetic to the challenges of modern travel.Expanding ball-shaped nominal headRadisson continues to expand its nominal head in lynchpin destinations in The Americas, Asia Pacifi c and Europe, the Middle East and Africa, comer stark naked markets and thickenings in major urban and suburban locations, as healthful as near airports and bloodline districts more or less the world.Yes I Can readiness chopine deliversAs split of its focus on node satisfaction, Radisson offers one of the hospitality industrys most can-do guest supporter preparedness plans calledYes I Can This program translates the marrow of the friendships service philosophy for hospitality honesty to the front-line service employees in Radisson operations worldwide. Celebrating its 20 year milestone in 2007,Yes I Canhas stupefy a central stir up of the Radisson culture, creating a point of difference for the dishonor.Our goal at Radisson is 100% Guest Satisfaction. If you be not satisfied with something, please let one of our staff screw during your stay and thoroughly conciliate it slump or you wont pay. Its Guaranteed.2.0 thought of merchandisingCarlson Sets brand-ne w Marketing Strategy for its Radisson Brand New Guest Room Concepts,New Restaurant Concepts and New do ConceptsORLANDO, Fla. ( ring 3, 2010) As part of its inhalation 2015 plan, Carlson today unveiled a oecumenical dodge for its Radisson brand. As one of the worlds confidential information brands, Radisson is being positioned to deliver vibrant, contemporary and engaging hospitality characterized by the Yes I Can service philosophy. The aligning is being aliment by a series of innovations including peeled get on concepts, new eating ho make use of concepts and a series of new service concepts concentrate on the guest do it. The strategy for Radisson lead entail an investment program of up to USD 1.5 meg in North America, focused on establishing flagship hotels in key U.S. cities and on upgrading the existing portfolio.It aims to expand its portfolio by at least 50 partage by 2015 to more than 1,500 hotels in operation.We believe this is a great cartridge holder to invest in the hotel business. With Ambition 2015, we engender a comprehensive and stimulate strategy to build the business, give tongue to Hubert Joly, president and chief executive officer, Carlson.Ambition 2015 testament focus on four priority growth initiatives includingExpanding Radisson as a powerful, globally consistent number one-class brand.Accelerating the growth of clownish auberges Suites By Carlson in four key markets linked States, Canada, India and Mexico.Growing Park Inn as a winning mid-scale brand across theaters in key countries.Continuing to grow in key acclivitous markets, with greater dialect on mid-scale.The strategy entails move the growth in key emerging economies such as Brazil, Russia, India and China, where it has gained signifi derrieret strength. For example, Carlson is the largest and fastest growing international hotel company in India with 79 hotels in operation or contracted at the end of 2009.These strategies go forth be back up by inve stments in marketing, gross gross revenue, diffusion and engineering science. As part of its Ambition 2015 strategy, Carlson Hotels expects to increase the contri only whenion from brand websites to 30 percent of revenue and to double the number of members in its goldpointsplusSM loyalty program.With 422 hotels in operation and 90 in the contracted pipeline, Radisson is one of the most well-known and fastest-growing brands in the world, delivering market leading guest satisfaction and achieving superior RevPar brainwave internationally, say Hubert Joly, president and chief operating officer of Carlson. We have crystallized the success convening for the brand, ameliorated it and atomic number 18 using it as the foundation for its future development.As part of this strategy, Carlson announced the global roll out of tail fin new room concepts And Relax, Naturally Cool, New York Mansion, Ocean and Urban. All of the concepts share a vibrant and contemporary design, the use of bold colors and lighting, and a prospering feeling.The global strategy alike includes two new restaurant concepts. Filini willing offer an upmarket, sophisticated Italian cuisine, while rbg is a bar-and-grill concept in an inviting, contemporary setting.The strategy as well introduces a range of service concepts account book binding the key touch points of the guest experience including, for example, business enterprise Class and three-hour laundry. melody Class will offer customers the vanquish available room, breakfast, turn- carry out service, upgraded bathroom amenities, a daily newspaper and other amenities depending on the market.As part of this strategy, the Radisson brand will be tiered across the upper upscale and upscale particles. Radisson Blu will be applied to the upper upscale segment and Radisson Green will be applied to the upscale segment. Both will share the alike(p) brand essence vibrant, contemporary and engaging the same style and many another(p renominal) of the service concepts. The differentiation will primarily be location posteriord key location in a primitive city versus a secondary market. It will typically be reflected in the level of investment that goes into the property.The strategy will include the implementation of the brands new global standard operating procedures, a new tonicity dominance program and intensive training programs. The strategy will be supported by investments in marketing, sales and distribution as part of the boilers suit Carlson Ambition 2015 plan.2.1 Marketing Strategy of RadissonUnder the leadershiphip of its former president, Radissons strategy focused on growth and the soaked added hotels at the rate of round one hotel every(prenominal) seven days. By 1997, Radissons growth at any cost strategy left Radisson with a signifi cigarettet diversity in hotel step and an unfocused brand image. Alignment with hotel owners (more than hotel guests) also seemed to cause Radissons custo mer service and hotel management expertise to atrophy.In 1997 and 1998, Mr. Brian Stage, Radissons President, and Ms. Maureen OHanlon, Radissons Executive Vice President, took some(prenominal) initiatives to drive the organization towards becoming a more customer-focused brand. In their words, they re-discovered that their ancient customers should be the guests not the owners. Some of these initiatives included a service reassure, a guest satisfaction measurement program, an employee satisfaction measurement program, and an information technology initiative. Stage and OHanlon were committed to creating the brasss and programs that would bring Radisson into the 21-st century as a truly customer-driven learning organization. Their goal was to make Radisson the most trusted and respected brand worldwide. They were hopeful that these initiatives would make a signifi cleart contribution to helping Radisson reach out these goals. process Quality Performance MetricsRadisson uses f our service quality performance metrics based on room comment card solicited from hotel guestsWillingness to return percent of customers who indicate that they are willing to return.Percent advocates percent of customers who indicate a willingness to recommend Radisson Hotels to others.Percent defectors percent of customers who indicate that they are unwilling to return.Percent complaints ratio of complaints to room nights.Information systems, under the leadership of Radissons Vice President of Knowledge Resources, Mr. Scott Heintzeman, produces a dashboard for each hotel that includes these and other more financial measures. The one-page dashboard is Radissons balanced scorecard for each hotel. These measures are often supplemented with ad hoc marketing research. This paper focuses on the service ascertain initiative, the four strategic service quality performance metrics that support the implementation and evaluation of that initiative, and a new measure called employee de mand and resource that was found to correlate highly with Radissons service quality performance metrics.RADISSONS profit GUARANTEEThe Service Guarantees Concept Hart2,3, hummock4, and others5,6 have argued persuasively that service guarantys can help many firms to position themselves in the market by all the way defining their value proposition to customers and employees. Service honorableifys also stress front-line workers to deliver high-quality service the first time, encourage customers to voice their complaints to the firm, and motivate and enable workers to quick discover and recover dissatisfied customers. Hays and Hill7 at the University of Minnesota actual a model (Figure 1) to show how service guarantees affect service quality and, ultimately, business performance. In this model, they argue that a strong service guarantee improves customer satisfaction, service quality, and customer loyalty through three interpose variables Marketing Communications equal, Employ ee Motivation and Vision, and organisational Service Learning. These are defined in the following paragraphs.Figure 1. Service guarantees and business performanceMarketing communications impact (MCI)Business performance (BP)Employee motivation and vision (EMV)Service guarantee strength (SGS) guest satisfaction Service quality node loyalty (SQL)Organizational service learning (OSL)Marketing Communications Impact (MCI) A strong service guarantee will have some(prenominal) offensive and defensive marketing impact. Offensively, firms can use a service guarantee to proclaim the reliability of their high quality service and thus attract new customers. Defensively, a service guarantee not but enables companies to recover unsatisfied customers but also encourages dissatisfied customers to complain, thus allowing the firm to recover those customers. Employee Motivation and Vision (EMV) A strong service guarantee motivates employees to fulfil the guarantee and to satisfy customers. The g uarantee clearly defines the employees job as satisfying customers not just taking reservations, checking out customers, or cleaning rooms. It can also inspire a new vision for service quality when employees are challenged to really satisfy customers true needs. Hill8 quotes one ranking(prenominal) European executive who proclaimed that our service guarantee defines the mission for our firm. Organizational Service Learning (OSL) A strong service guarantee can help organizations discover dissatisfied customers and learn from them in order to improve service quality. Organizations with a strong service guarantee will pitch learn how to satisfy customers faster than organizations without one. When marketing communications impact (MCI), employee motivation and vision (EMV), and organizational service learning (OSL) are improved, then service quality, customer satisfaction, and customer loyalty (SQL) should also improve. Business performance (BP) will improve as a result of improved SQL.2.1.1 Guerrilla MarketingWhen using social media for marketing it is not more or less broadcasting its about engaging. The most successful campaign is the one that engages and activates the most mountain to become the brands ambassador.The Radisson Blu Hotel brand with hotels in over 200 locations world-wide has started such a campaign. It seems to have started mid-May but is reaching its tipping point these days and is spreading fast.Its actually a very simple competition. They are giving awaythe sterling(prenominal) holiday in the world, probably inspired by the best job in the word. And the greatest holiday on Earth is 365 free nights at any Radisson Blu hotel in the world that the superior can use over the next five years. All you have to do to participate is signing up and verbalize the world why you should win.Its then up to the users to render as many people as possible to vote for them but each individual can vote once every day. The one with the most votes at t he end of the competition on July 24th will be the winner of the 365 free nights at any Radisson Blu. Simple and effective. Last Sunday night about one hundred fifty0 people had signed up and now, on Wednesday, there are about 3000 people competing. And those 3.000 people are now all actively promoting their spot in the competition and the hotel brand at the same time. non badTo encourage people further Radisson has enabled sharing options for twitter, face book and a number of other social networks and lists ideas on how people can promote themselves offline. One important thing is lacking though, which is a tag to put on a blog that automatically updates the ranking and encourages people to vote.2.1.2 Viral MarketingRadisson Hotel is providing the Best Online order Guarantee for their customers.Radisson.com, their homepage is customers home base for the best savings. they deliver customers best online rates guaranteed.Customers can feature the best online rate for their stay and they will get the best rate online they guarantee it. When customer books their reservation on Radisson.com, they can be confident they have gotten the best rate for their next visit.HowIt WorksIf you find a rate on another website that is demoralise than the bestrate on Radisson.com and the rate is for the same date(s), same room type, same number of guests, at the same hotel and same rate termsor restrictions- let them know andthey will honour the lower rate AND snub that rate by 25%.Qualifying regulatesRadissons Best Online Rate Guarantee applies only to online rates available to the general public. Group rates, corporate rates, wholesale rates, affinity/association rates or rates which are part of a travel package do not qualify.Radisson Customer Service will verify the rate meets all of the Best Online Rate Guarantee terms and conditions. Once confirmed you will receive the lower rate and 25% discount.Radissonguarantees that Radisson.com will have the best online rate available to their guests.3.0 Public Relation MethodMarch 24th, 2008, Radisson Hotel, Effective Business SolutionsseminarOn 24th of March, the Bulgarian funds newspaper arranged the Effective business solutions seminar in Radisson Hotel. The event was focused on ERP and CRM systems in order to help managers of trading and production companies raise the efficiency of their business processes. The point IT leaders were invited to present their products and Neme schek Bulgaria was one of them. In their exposition, the specialists of Nemetschek Bulgaria emphasized on the simple allowance of their system ( Customer Center) to the customers needs.Radisson Hotels Reviews Public Relation Prior To LaunchRadisson Hotels is reviewing PR for its of import hotels brand and is in the advanced stages of hiring an agency to launch a five-star hotel in Manchester.PR manager Jacquiline Willers said the company had seen pitches from four agencies and settled on a shortlist of two for the Manches ter brief, with local agency mason Williams and London-based Pineapple PR in contention.Willers refused to discuss fees for the two briefs, but said We have budgets for the Manchester project and for a two-year contract to help the Radisson Edwardian brand. It may be that one gets the Manchester job and the other the wider brief.At the moment, were not looking at other agencies for the two-year contract, but that may permute, she added.Radisson Edwardian has previously used Brighter PR for its PR work. The agency is not complicated in the current pitch process. Willers said the brief for the Radisson Edwardian Hotel Manchester will involve activity to drive bookings and awareness ahead of its opening in June 2004. The company claims the Manchester hotel will be the first five-star hotel in the centre of the city.However, Manchesters Lowry Hotel which falls just outside the city centre in neighbouring Salford and accommodated the England football police squad last weekend for i ts friendly against Denmark currently dubs itself the citys only five-star hotel, sparking speculation of a feud between the two hotels.But, Rocco Forte Hotels UK marketing director, Murray Thompson, played down talk of a spat, saying the opening of the Radisson in the city would make life easier for the Lowry Manchester is saturated with three- and four-star hotels and it will no longer be just us saying its worthwhile to pay for luxury, he said.Radisson SAS Hotel, Dubai Deira Creek, has appointed Stephanie AbouJaoude as its Public Relations and Communications Manager.The property is an established landmark on the Deira Creekside and was re-branded Radisson SAS this month.Lebanese-Canadian, AbouJaoude, involves up her new role following three years as Public Relations and Communications Executive at the InterContinental Hotel, Dubai where her main duties involved media relations, advertising and maintaining the corporate identity of the brand.Stephanie will spearhead all elements of internal and external communications. She will also oversee the propertys marketing programmes, said Andreas Flckiger, General Manager, Radisson SAS Hotel, Dubai Deira Creek.Her comprehensive knowledge of this property is a real summation to us and she will play an integral part in establishing this hotel under the Radisson SAS brand.Radisson SAS Hotel, Dubai Deira Creek has 287 guest-rooms, including 39 suites, 16 food and beverage outlets as well as meeting and events facilities.3.1 Relationship MarketingRadisson is part of the Carlson Hotels Worldwide system of hospitality properties which include Regent International Hotels, Radisson Hotels Resorts, Park Plaza Hotels, Country Inns Suites By Carlson, and Park Inn hotels. The parent company, Carlson Companies Inc., also owns and operates Radisson Seven Seas Cruises and T.G.I. Fridays restaurants. A world leader in Relationship Marketing, Carlson maintains a consumer loyalty program known as Gold Points Rewards.As one of the leading global hospitality companies, Radisson operates, manages and claims 435 full-service hotels and resorts, representing more than 102,000 guest rooms in 61 countries. From its franchise partners and strategic allies, to every manager and employee at every hotel, the Radisson organization is committed to providing personalized, professional guest service and Genuine HospitalityWith its focus on total guest satisfaction, Radisson employees undergo one of the hospitality industrys most dynamic guest relations training programs calledYes, I CanThis program translates the core of the companys service philosophy for hospitality excellence to the front-line service employees in Radisson operations worldwide. After more than a decade,Yes, I Canhas become a central part of the Radisson culture, creating a point of difference for the brand in the manner with which customers are served.Radisson hotels are named after the famous French explorer, capital of South Dakota Esprit Radisson, who visited many parts of the Upper Midwest and Canada during the 17th century.Radisson Gold Rewards offers guests the opportunity to earn and redeem Gold Points within an exclusive network of leading brands. Members who earn Gold Points can redeem them for free night stays, air hose miles, luxury cruises, merchandise, meals, and more. In addition to all of Carlsons brands, other major national partners in the Gold Points Rewardsnetwork include Thrifty Car Rental, The Flower golf-club and FTD.com.Currently, Gold Points are earned at all Radisson hotels in the unit of measuremented States, Canada, the Caribbean, Mexico, Central and South America. Residents of these countries can earn points at Radisson SAS and Radisson Edwardian hotels in Europe as well. Members of Radisson Gold Rewards earn 1,000 Gold Points per night, up to 10,000 points per stay.Radisson is continuing to add new hotels and resorts in key international business and leisure destinations. Examples of the companys highly successful partnerships include the development of Radisson SAS hotels and three other Carlson hotel brands in Europe, the Middle East and Africa, and Radisson Edwardian Hotels in the United Kingdom.Global presence and expansion into new markets is a key part of Radissons heritage. Radisson opened the first American-managed hotel in Moscow and today has several locations throughout Eastern Europe. Radissons recent entry into the United Arab Emirates, Lebanon and Saudi Arabia in December 2002, expanded the brands global presence to 61 countries.3.2 Customer LoyaltyAt Radisson, they are perpetually looking for ways to give customers that little something extra. Thats why they offer Goldpoints increase (goldpoints plusSM). Its the rewards program thats tailor-made for customers and their needs.goldpoints plusSM save nights Enjoyfree hotel nightsstarting at just 15,000 points. Combine a fewPoints + Cashfor an Award Night.Miles Exchange yourpoints for mileswith over 20 airline s.Prepaid Cards Cash in your points for Visaor MasterCardPrepaid Cards.Express Awards Redeem points at the hotel forExpress Awardslike movies, room upgrades and more.Make a Donation Gift your points to theWorld Childhood Foundationor to growth yourCO2 emissions.And some more attractive programmes those are really help them to get a loyal customer.100% SatisfactionIf you arent satisfied with something, please let one of our staff know during your stay and well make it right or you wont pay. Its guaranteed.Global LocationsWith over 400 Radisson locations worldwide, our doors are eer open to you. Ready to greet you with our signature Yes I CanTMservice.Free High-Speed InternetWe dont just wishing you to stay with us, we want you to have-to doe with with us. Thats why unlimited high speed Internet is free with your stay. complete Service Restaurant and Room ServiceHungry for satisfaction? Youll get it when you enjoy a meal in one of our full service restaurants. If you prefer to sta y in, help yourself to something from our room service menuBusiness CentersIts easy to stay on the job even when youre traveling. Our business centers are fully upgraded to fit the way you work today.Pool and Fitness Centers put across your downtime shaping up in our modernized fitness centers or take the plunge poolside and stay fit when youre on the go.Meeting and Banquet FacilitiesWhether youre cookery a business meeting or a family celebration, were here to help. With the blank shell and the services that will make your event special in every way.4.0 Effectiveness of Marketing and Public Relation strategyHotels Resorts is committed to change and innovation in all key areas including its growthstrategy ,operations, franchising, sales and marketing and technology, to operate with maximum effectiveness in a highly competitive business environment . Technology will undoubtedly continue to develop andRadisson Hotels should continue to progress along with it to stay on top of these rvice industry as one of the best global hotelcompanies out there.ORLANDO, Florida As part of its Ambition 2015 plan, Carlson today unveiled a comprehensive strategy for its Radisson brand. As one of the worlds leading brands, Radisson is being positioned to deliver vibrant, contemporary and engaging hospitality characterized by the Yes I Can service philosophy. The positioning is being supported by a series of innovations including new room concepts, new restaurant concepts and a series of new service concepts focused on the guest experience. The strategy for Radisson will entail an investment program of up to USD 1.5 billion in North America, focused on establishing flagship hotels in key U.S. cities and on upgrading the existing portfolio.With 422 hotels in operation and 90 in the contracted pipeline, Radisson is one of the most well-known and fastest-growing brands in the world, delivering market leading guest satisfaction and achieving superior RevPar penetration international ly, said Hubert Joly, president and CEO of Carlson. We have crystallized the success formula for the brand, improved it and are using it as the foundation for its future development.As part of this strategy, Carlson announced the global roll out of five new room concepts And Relax, Naturally Cool, New York Mansion, Ocean and Urban. All of the concepts share a vibrant and contemporary design, the use of bold colors and lighting, and a comfortable feeling.The global strategy also includes two new restaurant concepts. Filini will offer an upscale, sophisticated Italian cuisine, while rbg is a bar-and-grill concept in an inviting, contemporary setting.The strategy also introduces a range of service concepts covering the key touch points of the guest experience including, for example, Business Class and three-hour laundry. Business Class will offer customers the best available room, breakfast, turn-down service, upgraded bathroom amenities, a daily newspaper and other amenities dependin g on the market.As part of this strategy, the Radisson brand will be tiered across the upper upscale and upscale segments. Radisson Blu will be applied to the upper upscale segment and Radisson Green will be applied to the upscale segment. Both will share the same brand essence vibrant, contemporary and engaging the same style and many of the service concepts. The differentiation will primarily be location based key location in a primary city versus a secondary market. It will typically be reflected in the level of investment that goes into the property.The strategy will include the implementation of the brands new global standard operating procedures, a new quality assurance program and intensive training programs. The strategy will be supported by investments in marketing, sales and distribution as part of the overall Carlson Ambition 2015 plan.We have seen the power of the brand internationally and the very attractive return from renovating to the new standards, Joly said. The brand is poised for significant growth around the world and we expect to grow the portfolio to at least 600 hotels by 2015.Media interested in getting sixth sense into Carlsons new global vision and corporate strategy are invited to view the live webcast of Hubert Jolys opening keynote atwww.carlsonhotelsmedia.com/ambition2015at 430 p.m. ET. A replay of this webcast will be available starting at 8 p.m. ET, Wednesday March 3, 2010.Effective Integrated Marketing StrategyIntegration marketinghappens when two different, but complementary offers are made in succession, or when a Unit of Marketing Value is placed in front of an existing barter stream. Radisson offers sleep number beds in many of their rooms. These beds allow guest to sort out the firmness to their liking. In this case, the integration is that, as a Radisson customer, they are authorize to receive Free home delivery, setup and removal OR $150 worth of accessories on select Sleep Number beds. The promotion is co-brand ed to reinforce that being a Radisson client has its special perks and privileges that they are looking out for customers well-being even when they are not staying at their hotel. In fact, they want the experience of sleeping in customers own bed to mimic the experience of sleeping in their bed. Integrated marketing is happening all around the guest all they have to do is look for it.5.0 Recommendation and final stageReferenceswww.radisionhttp//www.hotel-online.com/News/PR2010_1st/Mar10_RadissonPlans.htmlhttp//www.greatestholiday.radissonblu.com/http//www.nemetschek.bg/press/index.htmhttp//www.discoverfrance.net/Boutique/Travel/Hotels/Chains/Radisson.shtmlSERVICE GUARANTEES AND strategical SERVICEQUALITY PERFORMANCE METRICS AT RADISSONHOTELS WORLDWIDEArthur V. Hill*, Susan Geurs, Julie M. Hays, George John, David W.Johnson, and Richard A. SwansonCase Analysis Customer-Driven Learning at Radisson Hotels WorldwideReferencesAl, L. (1993). Service guarantees in outpatient clinics a c ase study. Health Care Management Review, 18 (3), 59-65. Cahill, D. J., Warshawky, R. M. (1995). beyond competence unconditional guarantees as a customer-service tool. Journal of Customer Service inMarketingand Management, 1 (3), 67-77. Hart,Bibliographyhttp//travel.yahoo.com/p-hotel-360091-radisson_ambassador_plaza_hotel_and_casino-i

Hydrogels for Wound Healing Applications

Hydro gels for s send worddalise Healing Applications reverseThis chapter talk overes just ab knocked out(p) the hydrogels two raw(a) and unreal that restrict be delectationd for s lavdalise break clear up exercises. withal it discusses briefly about the various unexampled proficiencys that pass on been au indeedtic recently.KeywordsHydrogels Chitosan, germicide Grafting Blending Wound book binding Wound improve gene therapy, Stem kiosk therapy, Skin Engineering, pH and Thermosensitive polymers.1 Introduction healthc ar is an demand aspect of human survival. So m every(prenominal) biopolymers pitch gene readyd by-line in a number of bio medical examination applications. Wound c atomic number 18 is ane such field of honor whither management of cuts, ulcers, and sores of necessity bindings which help in promoting quick hurt amelio range in h completelyow to obtain both operating(a) and cosmetic results. 45 in that respect ar opposite lovables of infract management products staples or sutures, fertilisations or bandages, surgical sealants and adhesives, flake substitutes, and new(prenominal) bio squ ars. 51Human splutter proposes an trenchant barricade to microbial penetration and ensuant transmission system. However, once the impairment has been s oftened in this barrier, the infection chances increases. In courting of continuing injurys, the colonization and infection potential increases as the result of the armorial bearing of avascular eschar which provides an milieu for the unsuppressed ingathering of microorganisms. 89 The target of infection is cerebrate to the flake of go against, general s nookiedalise cargon, and local health of the patient. 88, 90 For avoiding infection, serious clinical utilizes argon undeniable.The management of chronic app solelys is a very costly practice and it overly places an enormous drainpipe on health fretting resources studies go for mensurable the c ost of breaks to the NHS to be about 1bn a year. 166 So for fr experienceing this cost such s housealize management products atomic number 18 collected that atomic number 18 to a greater extent(prenominal) than economical and pitchive. prohibited of all in all the above tease management products, here in this chapter we leave al superstar discuss more about the shocking stuffings that will provide an optimum improve environment to the breach. A stuffing is an accessary use by a person for application to a contuse in order to nurture mend and/or retain advertize harm. It is knowing to be in direct contact with the aggravate, so it is contrary from the bandage in the carriage that bandages be designly use to h older get dressed in place.A bruise is a break in the epithelial integrity of the whittle and whitethorn be accompanied by disruption of the structure and wreak of underlying normal wind. Wounds push aside be divided into four categories base on their appearance and stage of improve Necrotic, sloughing, granulating and epithelializing provokes. 87 Wounds cause discomfort and argon more pr whizz to infection and opposite troublesome complications. 75 just about diseases like diabetes, ischaemia and conditions like malnourishment, ageing, local infection, local create from raw material damage collect equal to burn leads to delay in break improve. Infection is a major(ip) complication of burn reproach and is responsible for(p) for 50-75% of hospital deaths. 76Human skin has iodine of the considerableest capacities to regenerate itself amongst all of the tissues in our body. It constantly replaces old stalls with new cells, change it to repair itself when damaged. Wound ameliorate is a complex-physiologic summons, which consists of triple overlapping phases inflammatory, proliferative and remodeling phases. The normal ameliorate chemical reaction begins the moment the tissue is hurt. As the blood compo nents spill into the send of injury, the platelets go up into contact with exposed collagen and new(prenominal) elements of the extracellular matrix. This contact triggers the platelets to red ink clotting factors as well as essential growth factors. During the inflammation process, neutrophils are the first leukocytes which come at the turn up of injury to rid it from bacterial contamination. Then, the monocytes and their conversion to macrophages initiate tissue repair by releasing a number of biologically ready substances and growth factors that are necessary for the commencement of tissue actinotherapy patternation process. In the third process, fibroblasts proliferate and migrate into the appal space and started the deposition of the easy extracellular matrix. Endothelial cells grow into a irritate at the same time with fibroblasts and sustain angiogenesis. Finally, tissue remodeling takes place to reconstruct the root cellar tissue socio-economic class by the distinction of keratinocytes as well as the throwation of follicle cells. 43, 49, 50 A scar is an essential part of this congenital improve process fol commencementing any typeface of damage to the skin. This passel occur aft(prenominal)ward a surgical abrasion or the healing of a harm. As your body falsifys an effort to finish an open wound and protect itself from infection, it replaces injured skin tissue with rapidly generated scar tissue. Scarring is s out of work when the damaged outermost stage of skin is vul ignoreized by rebuilt tissue. When we damage the thick story of tissue beneath the skin, make is more complicated. Our bodies lay down collagen fibers (a protein which is lifelikely produced by the body) and this usually results in a highly obvious scar. A permanent reminder of the injury is unexpended behind. So, a grooming that send packing induce scarless healing is needed.Historically, a fecundation was usually a paper of material, some gene ration cloth, entirely the use of cobwebs, dung, leaves and honey has in appendage been described. However, modern dresss involve gauzes, semipermeable characterizations, first gear stakeer dresss, gels, foams, hydrocolloids, alginates, hydrogels and polysaccharide pastes. Wound dressings are passive, energetic voice or interactive. Passive dressings only provide cover while active or interactive dressings are unfastened of modifying the physiology of the wound environment. Interactive dressings complicate hydrocolloids, hydrogels, alginates, foam dressings and healthful dressings. 17, 20, 85 tralatitiously modify wound dressings are considered to be good for healing wounds i.e. the wound should be covered with gauze or left open. hardly it has been sight by Winter 191 that when wound is left open to air without any dressing, a scab i.e. a teetotal covering covers the wound and ebbs the rate of epithelialization. On the early(a) hand, if awry(p) dressing is u tilise in place of dry dressings scab will not form and rate of healing increases as moist dressings provide low type O tension which helps in wound healing, these dressings not only keep cells viable which enables them to put out growth factors while claiming contact amid them and the healing tissues, but whitethorn withal modulate or stimulate their proliferation, these dressings pass the pain at rest, during ambulation and during dressing changes also moist environment allows rapid and efficient delivery of any added antimicrobic agent thence prohibit the wound from infection. So, the dressings that create and aver a moist environment, however, are at a time considered to provide the best conditions for wound healing.2 Requirements of an ideal wound heraldic bearing systemThese characteristics should be personate in the ideal wound care system (a) it should be capable of maintaining a high humidity at the wound site, (b) it should be non-toxic, (c) non-allergenic, ( d) it hindquarters be re touch ond without causing trauma to the wound, (e) it should pe impermeable to bacteria, (f) Thermally insulating, (g) it should be soft to touch, (h) it should allow ripe e vaporizationated exchange, (i) it should be exempt from particulate and toxic product, (j) promote tissue re spin processes and (k) it should be cost effective. 20, 165, 177Out of all the dressings hydrocolloids, alginates and hydrogels each one has its own advantages and limitations but hydrogels are go around and nominate all the characteristics that are needed in an ideal wound dressing. All the above mentioned characteristics can be achieved in hydrogel wound dressings.3 Hydrogels for Wound Healing ApplicationsHydrogels are immanent or unreal cross-linked polymers utilise in a variety of medical and biomedical applications. Hydrogels consist of a matrix of water-insoluble polymers with up to 96% water content enabling them to donate water molecules to the wound out and to maintain a moist environment at the wound bed. They are utilize in the construction of contact lenses, venereal infection-delivery vehicles, wound dressings and as physiologic electrodes or sensors. 17 Examples of hydrogel embarrass Aquaform, Intrasite, GranuGel, Nu-Gel, Purilon, Sterigel.These also hurt the ability to drag a degree of wound exudate. They broadcast moisture dehydration and conclave O, but their bacterial and fluid permeability is low-level on the type of plunk forary dressing employ. 20 Hydrogels swell or reduce in aqueous ancestors cod to the association, disassociation and binding of various ions to polymer manacles. These systems may swell in water until an proportion state is reached and retain their master key shape. The inter proceedings responsible for water sorption by hydrogels include the process of hydration, which is connected to the battlefront of such chemical groups as -OH, -COOH, -CONH2, -CONH-, and -SO3H and the institution of capillary areas and differences in osmotic pressure. The forces that make hydrogel dissolution impossible are presence of covalent bonds between individual polymer chains, hydrophobic and electrostatic fundamental interactions. 46These are hydrophilic polymer ne dickensrks which may absorb from 10-20% (an arbitrary commence limit) up to thousands of times their dry weight in water. These may be chemically horse barn or they may enter and dissolve. They are called reversible, or sensual gels when the vanes are held together by molecular(a) entanglements, and/or secondary forces including ionic, H-bonding or hydrophobic forces. 13, 14, 15 Hydrogels are called permanent or chemicalgels when they are covalently-crosslinked ne dickensrks as manoeuvern in 1.Hydrogels can be made by irradiation, bar-thawing or chemical modes. Out of all the methods, irradiation is considered as a suitable tool for the formation of hydrogels as in this method in that location is easy control of pro cessing, no need of adding initiators or cross-linkers which are harmful, and have the possibility of formation and sterilization in one step. barely as everything has its own advantages and disadvantages this method also has a disadvantage which is hydrogels make by this method have poor automatic aptitude. Nowadays, Freeze thawing technique is generally apply to prepare hydrogels having good military unit, stability and no crosslinkers and initiators. But the main disadvantage is that the inclined(p) hydrogels have opaque appearance and control gibbousness and thermal stability. 120In par to the traditional gauze therapy the application of a hydrogel seems to portentously stimulate wound healing. 11 Various inbred and unreal polymers having good biocompatibility are use to develop hydrogel wound dressing. These polymers include natural polymers such as alginate, chitosan, jelly and collagen and unreal polymers such as polyurethane, poly(ethylene glycol), polycaprol actone, poly vinyl radical pyrrolidone, poly(lactide-co-glycolide), polyacrylonitrile , poly( aminic acid), and so forth parry 1 under shows different hydrophilic polymers utilize to synthesize hydrogel matrices.Table 1 deliquescent polymers used to synthesize hydrogel matrices. 13Hydrogels may be classified as homopolymer hydrogels, copolymer hydrogels, multipolymer hydrogels, and interpenetrating polymeric hydrogels. Homopolymer hydrogels are crosslinked networks of one type of hydrophilic monomer unit, whereas copolymer hydrogels are produced by the crosslinking of two comonomer units, one of which must be hydrophilic. Multipolymer hydrogels are produced by the crosslinking of more than terzetto monomers. Finally, interpenetrating polymeric hydrogels are produced by the swelling of a first network in a monomer and the answer of the latter to form a second intermeshing network structure. 46, 47Also, it has been shown that the operateing of a natural polymer with a synthe tical polymer seems to be a good method for obtaining materials having required automatonlike and thermal properties in comparison to pure components. It is also a simple method by which suitable shapes such as films, lounge abouts and hydrogels can be obtained easily to look a variety of biomedical artifices.2 shows healing is faster with the hydrogel dressing than with the gauze dressing. Wound area covered by hydrogel decreases faster with change magnitude healing period. On the contrary, the wound covered by gauze dressing reduces by only half a percent even after 14 days. 1923.1 innate(p) HydrogelsNatural polymers, such as chitin, chitosan, alginate, collagen, elastin, genipin, gelatin, cellulose etc. have been used for dressing wounds because they scam an alpha role in the healing process. 47Chitosan is a partially deacetylated form of chitin. Chitin as Beschitin, Unitika, is also mercenaryly forthcoming as dressing in Japan. 28 But as far as chitosan is concerned i t is biocompatible, biodegradable, haemostatic, fungistatic 54 and non-toxic and can be successfully used as gels, films, fibres etc. This polymer also show bacteriacide properties and possess good wound healing properties. 60, 61, 62 It has many a(prenominal) another(prenominal)(prenominal) applications as wound dressing, medicine delivery device and as scaffold for tissue engineering. 63, 64 Some of the examples of wound dressings are pull up stakesn beneath which use chitosan as one of the biomaterial.Asymmetric chitosan tissue classs have been developed by using immersion-precipitation phase-inversion method. 123, 124, 125 These asymmetric chitosan tissue layers are homogeneous and have poriferous structure. This membrane was prepared by preheating casted chitosan solution in oven for different time periods for dry phase withdrawal and then immersed in to coagulant tank for wet phase legal separation and were later freeze-dried. The skin layer acts as the rate controll ing barrier for the uncover of medicate and the poriferous layer provide mechanized support to the skin layer. The water vapor transmission rate, botch permeability, PBS solution preoccupation, in-vitro degradation, cell culture, bacterial penetration and wound healing render of this dressing were carried out. These membranes are effective in controlling evaporative water loss, showed excellent oxygen permeability and also bactericide drug in temper. These are also undercoat to be an urgent hemostat. In another study, currency sulphadiazine was compound as an antimicrobial agent to this asymmetric dressing. The release behaviour of both silver and sulphadiazine ions were studied and install to be importantly different from one another. cash ions displayed a bleak release manner while sulphadiazine ions exhibited burst effect on first day of the drug release and then soft tapered off. It is because of the interaction of silver with amino group of chitosan leading to its slow release throughout whereas, as the sulphadiazine ions were free to diffuse through the membrane to reach the wound site thus they showed a burst release. The membranes were march on pitch effective against P. aerugniosa and S. aureus.In one of the papers, novel wound dressings were formed that self-possessed of chitosan film and Minocycline Hydrochloride (MH) and commercial polyurethane film (Tegaderm) as a backing. It is also a reclaimable formulation for the treatment of everlasting(a) burn wounds. Water vapor and oxygen can permeate the Tegaderm film but water cannot. The tegaderm film support the polymer membrane. 126In one of the studies, a silver nanocrystalline chitosan (SNC) wound dressing imperturbable of nano-silver and chitosan was constructed by self-assembly and nanotechnology and used for treating cloudy partial-thickness wounds. In this, sterility and pyrogen exam were performed to ensure biosafety. These dressings promote wound healing and combat inf ection, and also decrease the risk of silver preoccupancy in comparison with silver sulphadiazine (SSD) dressings. 127There is also one more method of forming wound dressing placid of chitosan i.e. the formation of polyelectrolyte complex of apply kondagogu (GKG) and chitosan. This complex is formed by the electrostatic interaction between carboxyl group of gum and amine group of chitosan. This method is more expedient as it avoids the use of organic solvents, chemical crosslinking agents and thus reduces the toxicity and undesirable side effects. In this, diclofenac sodium is used as model drug. The diclofenac flush(p) complex of gum kondagogu/ chitosan shows drug release which changes with change in pH. The drug release was higher at pH 6.8 as compared to pH 1.2, referable to higher swelling of complex at higher pH. This exerts a great potential as a natural polymer based delivery device for controlled delivery of drugs like diclofenac sodium for two reasons (i) to reduce d osing frequency and (ii) lower the gastric toxicity. 152Semi-interpenetrating polymer networks (SIPNs) undisturbed of chitosan (CS) and poloxamer were prepared in order to improve the automatonlike strength of CS. The WVTR was name to be 2508.265.7 gm2 day1, i.e. these can maintain a moist environment at wound site which enhance epithelial cell migration. Also, the in vitro assessment of SIPNs showed proper biodegradation and low cytotoxicity and in vivo is carried out on experimental full thickness wounds in a mouse model and found that the wounds covered with these were completely modify with new epithelium without any significant adverse reactions after 3 weeks.In one of the papers, a kind of surgical wound dressing, the chitosan-gelatin purify wound dressing (CGSWD) having good bacteriacide property is prepared. The in vitro evidence showed that the antibacterial effect of CGSWD on E. coli K88 is better than that of penicillin, and the effect on S. aureus is also better than that of cefradine. 137One more wound dressing consists of two dismantle layers were prepared in which the velocity layer is a swellable hydrogel material which can absorb exudates and also serve as mechanical and microbial barrier while lower layer is a chitosan acetate foam incorporated with the anti-microbial agent chlorherxidine gluconate. 183 The antimicrobial legal action is checkered by the Bauer-Kirby Disk airing Test, inhibition zones can be clearly seen around the discs of chitosan acetate foams incorporated with chlorhexidine gluconate, in culture plates inoculated with either negative or positive bacteria showing that the dressing is antimicrobial in temper.Blending is a favorable and effective method to improve physical and mechanical properties of hydrogels. So revision of chitosan is done by blending with other polymers like cellulose. 178 In this, E. coli and S. aureus were used as the test bacteria to quiz the antibacterial properties of chitosan, cel lulose and chitosan/cellulose blends. The numbers of village of these bacteria formed on the test membranes are shown in s 5 and 6. It was noted that the numbers of liquidation of all test bacteria formed on the chitosan/cellulose blend membranes were decrease with the increase of chitosan concentration. These blends are more effective against E. coli than that of S. aureus, as indicated by the lower colony unit. Thus these dressings are suitable to use as an antimicrobial wound dressing.Chitosan delinquent to its morphologic properties has the ability to heal wounds without scar formation. 198 Since chitosan is comprise of D-glucosamine, which is also the component grant in the disaccharide subunits of hyaluronic acid, chitosan tries to structurally mimic hyaluronic acid and exerts similar effects. 197 It has been known that the fetal wound healing takes place without fibrosis or scar formation due to the presence of hyaluronic acid. 199In one of the studies, Chitosan as a se mi-permeable biological dressing maintains a moist environment and prevent the wound site from vaporisation and contamination. In improver, digital colour separation analysis of donor site scars demonstrated an earlier return to normal skin colour at chitosan-treated areas as shown in 7. 196Collagen is also a biopolymer that is used as a polymer for making wound dressing and drug delivery devices as it is biocompatible and biocompatibility of a material use to wound tissue is a prerequisite for optimal wound environment and facilitation of the healing processes. A new collagen dressing with gentamycin or amikacin was prepared in one of the question work and these follow the fundamental requirement of antibacterial bandages. The dressing is composed of two collagen biomaterialsmembrane and mopboth possessing good tissue biocompatibility. These dressing released antibiotics slowly and show the antibacterial treatment in experimentally infect superficial wounds in mice. Thus, it can be used for the treatment of give wounds in humans. 26As discussed previously that both chitosan and collagen are excellent materials that can be used as wound dressing materials. So it has been seen that if both are used simultaneously then what will be the effect. It is found that the wound dressings composed of chitosan crosslinked collagen sponge (CCCS) enhance the diabetic wound healing. Collagen crosslinked with chitosan showed some(prenominal) advantages required for wound dressing, including the resembling and porous ultrastructure, less water imbibition, lilliputian interval porousness, and high safeguard to collagenase digestion and slow release of FGF from CCCS/FGF. 138Following moist healing concept, alginates which are able to absorb exudates from wound have suffer one of the most all important(p) materials for wound management. 52, 53, 54, 55, 56 In this particular field, the properties of alginate fibers are unparalleled in many respects. Alginate based p roducts form a gel and effective in removing out of the wound on the contrary to traditional cotton and viscose fibres, which can entrap in the wound developing discomfort during dressing removal. 55 Also, the alginate fibres are non-toxic, non-carcinogenic, non-allergic, haemostatic, biocompatible, of reasonable strength, capable of macrocosm sterilized and easily processable. Sorbsan was first commercialized in 1981 and after that there were many dressings launched. The alginate fibers can be converted into wound dressings by using a number of textile processes. Because of its repose and also the high absorbency of the product, nonwoven is the main form of alginate wound dressings. 19The antimicrobial action of alginate dressing can be seen as in 8 which shows the antimicrobial action of silver containing alginate fibers against E. Coli. There was hundred% reduction in bacteria count within 5 hr after the fibers were hardened in contact with solutions containing the bacteri a. Sorbsan alginate fibers showed some antimicrobial activity while AquacelTM (made of carboxymethyl cellulose), does not show any antimicrobial effect. 18 gel longly found in nature and is the major constituent of skin, bones, and connective tissue. Gelatin can easily be obtained by a controlled hydrolysis of the fibrous insoluble protein, collagen. 195 This is also used in number of biomedical applications like wound dressings. Hydrogel wound dressing from gelatin, oxidate alginate and borax were prepared and the involved matrix promotes wound healing because of alginate, has haemostatic effect of gelatin and is antiseptic because of borax. The water vapour transmission rate (WVTR) of the hydrogel was calculated and found to be 2686124 g/m2/day indicating that this hydrogel can maintain a proper fluid balance at the wound site which helps in cell migration. 2 shows the loss of water vapour with time through the hydrogel when placed in a moisture plenteous environment. 119Geni pin has been used to crosslink chitosan membranes to control swelling ratio and mechanical properties. It increased its crowning(prenominal) tensile strength but significantly reduced its strain-at-fracture and swelling ratio. It had significantly less cytotoxicity for human fibroblasts and dilatory degradation rate compared to the glutaraldehyde-crosslinked membrane. This genipin crosslinked chitosan membrane can be successfully used as a wound dressing. 132bacterial cellulose is a natural polymer consisting of microfibrils containing glucan chains bound together by atomic number 1 bonds. Bacterial cellulose with chitosan combines properties such as bioactivity, biocompatibility, and biodegradability of the two biopolymers and form an ideal material for dressing wounds. 66, 67 These are antibacterial and scar preventive in nature too.Since natural polymers have been considered limited in their applications for wound-dressing materials as their low mechanical properties and sho rtage of processing. So we move towards the synthetic polymers that can be used for wound healing applications.3.2 synthetic substance HydrogelsSynthetic polymers are also being used successfully in biomedical applications as one of the materials because of their wide range of mechanical properties, suitableness for easily forming into a variety of different shapes, and low production costs.In an ideal dressing both the characteristics i.e. antimicrobial ability and moist healing environment should be present, so in order to prevent the wound from dehydration and bacterial penetration a new dressing composed of polyurethane is designed in such a way that the upper layer of the dressing is microporous ( centre size Polyvinyl pyrrolidone (PVP) is one of the most widely used synthetic polymers in medicine because of its solvability in water and its extremely low cytotoxicity. Hydrogels prepared by radiation crosslinking of an aqueous solution of polyvinyl pyrrolidone (PVP) have been used as wound dressing. 21 These are biocompatible, reduces pain, easily replacable, permeable to oxygen, maintain moist environment at the wound site.Polyvinyl alcohol (polyvinyl acetate) is a well-known polymer because it is biocompatible and have required mechanical properties and polythene oxide (PEO) is a hydrophilic semicrystalline polyether which is biocompatible, non toxic, non polar, non antigenic and non immunogenic and is highly desirable in most biomedical applications requiring contact with physiologic fluids.A hydrogel composed of PEO for wound dressing is prepared and PVA is added to give toughness to the hydrogel by electron convey irradiation and found that these hydrogels showed satisfying properties for wound dressing that has been evaluated by creating wound on the back of the marmots. 157 The hydrogel gives a wet environment to wounds which causes faster healing compared with the gauze dressing with a dry environment. The weight of the hydrogel increases qui ckly at the earlier stages, up to 4 days, due to absorption of effusion produced from the wound as shown in Table 2. After that, the production of effusion from the wound ceases and the weight of the hydrogel decreases due to drying up of the water in the hydrogel. This means that the healing of wound proceeds swimmingly with time. The hydrogel can be peeled off easily from the wound at the time of removal.Table 2 tightness of effusion from wound of dressing during healing. 157The toughness of PEO hydrogel is improved by the addition of PVA and tensile strength is measured and found that as shown in 10 and 11, the tensile strength and elongation decrease with increasing dose because of the increase of crosslinking.Various synthetic polymers as discussed above are used for wound dressing applications. But the major problem with these materials is their biocompatibility characteristics are often unsatisfactory and their interaction with spiritedness tissues is a major problem. So a combination of both natural and synthetic polymers is the better option to make a hydrogel having biocompatibility and desired mechanical strength.3.3 Blended hydrogelsSince both the natural and synthetic polymers have their own advantages and disadvantages so a combination of natural and synthetic polymers can endow the optimal properties necessary for wound repair. 47 The combination of natural and synthetic polymers is used in the biomedical, bioengineering and biotechnology field immediately because of their great potential.A intermix hydrogel composed of polyvinyl alcohol/polyvinyl pyrrolidone and charcoal were prepared by single freeze and thawing or two-step freezing and thawing and -ray irradiation and applied as wound dressing. It is found that the absorption of S. aureus and P. aeruginosa by charcoal/PVA/PVP hydrogels was bigger than those by PVA/PVP hydrogels, this is due to the absorption and attachment ability of bacteria by charcoal, this can be shown in 12 attac hed below. 22The most classical way of clothating a CS based wound dressing has been to design an asymmetric composite structure. In this method, the Cotton fabric was coated with chitosan (CS) and polyethylene glycol (PEG) followed by freeze-drying. The outer dense layer helps in preventing the microbial passage crosswise the dressing and provides a rate controlling barrier for water vapor permeation, while the inner porous layer provides a high near area for the exudates absorption. For the absorption of wound exudates porosity is the prime requirement in a dressing. It has been found that these dressings have the porosity 54-70% and the pore size was in the range of 75-120m. 45 The increase in the PEG content in the blend composition led to an enhance destabilization of pores, leading to an increase in the pore size with drawn-out morphology. There seems to be phase separation between the two components which is an important factor for the discovered behavior of the porous st ructure. Cotton fabric has been used as the support layer for the CS-PEG layer and leads to very thin and light weight structures. The structure of the dressing has been designed in such a way that it leads to the high porosity of the pop out structure. The thickness of CS application program plays an important role in the tuition of the porosity on the rear. The ferment of the CS thickness on the surface morphology is presented in 13 given below.PEG addition to CS makes significant alteration in the surface morphology of this CS-PEG/cotton membrane (freeze-dried), henceforth known as CPC membrane. There is a distinct foreshorten in the loss of inhering elongated porous structure in membranes and formation of the partially collapsed porosity takes place due to the PEG addition. This suggests that a very limited interaction between CS and PEG exists which is reflected in the observed surface morphology. It has been observed that higher the amount of PEG, the higher is the pore destabilization leading to larger pores. This is evident from the morphology of the CPC membrane at 50% PEG-20 content as shown in 14.45On the above matrix, the addition of PVP and drug followed by pelage on the cotton fabric and freeze drying of the coated matrix is also done. It has been found that the drugHydrogels for Wound Healing ApplicationsHydrogels for Wound Healing ApplicationsAbstractThis chapter discusses about the hydrogels both natural and synthetic that can be used for wound healing applications. Also it discusses briefly about the various novel techniques that have been developed recently.KeywordsHydrogels Chitosan, Antimicrobial Grafting Blending Wound dressing Wound healing Gene therapy, Stem cell therapy, Skin Engineering, pH and Thermosensitive polymers.1 IntroductionHealthcare is an essential aspect of human survival. So many biopolymers have generated interest in a number of biomedical applications. Wound management is one such area where management of cuts, ulcers, and sores needs dressings which help in promoting rapid wound healing in order to obtain both functional and cosmetic results. 45 There are different kinds of wound management products staples or sutures, dressings or bandages, surgical sealants and adhesives, skin substitutes, and other biomaterials. 51Human skin provides an effective barrier to microbial penetration and subsequent infection. However, once the wound has been developed in this barrier, the infection chances increases. In case of chronic wounds, the colonization and infection potential increases as the result of the presence of avascular eschar which provides an environment for the uninhibited growth of microorganisms. 89 The rate of infection is related to the type of wound, general wound care, and local health of the patient. 88, 90 For avoiding infection, good clinical practices are needed.The management of chronic wounds is a very costly practice and it also places an enormous drain on healthcare resource s studies have calculated the cost of wounds to the NHS to be about 1bn a year. 166 So for lowering this cost such wound management products are needed that are more economical and effective.Out of all the above wound management products, here in this chapter we will discuss more about the wound dressings that will provide an optimal healing environment to the wound. A dressing is an adjunct used by a person for application to a wound in order to promote healing and/or prevent further harm. It is designed to be in direct contact with the wound, so it is different from the bandage in the manner that bandages are normally used to hold dressing in place.A wound is a break in the epithelial integrity of the skin and may be accompanied by disruption of the structure and function of underlying normal tissue. Wounds can be divided into four categories based on their appearance and stage of healing Necrotic, sloughing, granulating and epithelializing wounds. 87 Wounds cause discomfort and a re more prone to infection and other troublesome complications. 75 Some diseases like diabetes, ischaemia and conditions like malnourishment, ageing, local infection, local tissue damage due to burn leads to delay in wound healing. Infection is a major complication of burn injury and is responsible for 50-75% of hospital deaths. 76Human skin has one of the greatest capacities to regenerate itself amongst all of the tissues in our body. It constantly replaces old cells with new cells, enabling it to repair itself when damaged. Wound healing is a complex-physiologic process, which consists of three overlapping phases inflammatory, proliferative and remodeling phases. The normal healing response begins the moment the tissue is injured. As the blood components spill into the site of injury, the platelets come into contact with exposed collagen and other elements of the extracellular matrix. This contact triggers the platelets to release clotting factors as well as essential growth facto rs. During the inflammation process, neutrophils are the first leukocytes which come at the site of injury to rid it from bacterial contamination. Then, the monocytes and their conversion to macrophages initiate tissue repair by releasing a number of biologically active substances and growth factors that are necessary for the initiation of tissue formation process. In the third process, fibroblasts proliferate and migrate into the wound space and started the deposition of the loose extracellular matrix. Endothelial cells grow into a wound simultaneously with fibroblasts and undergo angiogenesis. Finally, tissue remodeling takes place to reconstruct the basement membrane by the differentiation of keratinocytes as well as the formation of follicle cells. 43, 49, 50 A scar is an essential part of this natural healing process following any type of damage to the skin. This can occur after a surgical incision or the healing of a wound. As your body makes an effort to close an open wound a nd protect itself from infection, it replaces injured skin tissue with rapidly generated scar tissue. Scarring is slight when the damaged outer layer of skin is healed by rebuilt tissue. When we damage the thick layer of tissue beneath the skin, rebuilding is more complicated. Our bodies lay down collagen fibers (a protein which is naturally produced by the body) and this usually results in a highly obvious scar. A permanent reminder of the injury is left behind. So, a dressing that can induce scarless healing is needed.Historically, a dressing was usually a piece of material, sometimes cloth, but the use of cobwebs, dung, leaves and honey has also been described. However, modern dressings include gauzes, semipermeable films, low adherent dressings, gels, foams, hydrocolloids, alginates, hydrogels and polysaccharide pastes. Wound dressings are passive, active or interactive. Passive dressings simply provide cover while active or interactive dressings are capable of modifying the phy siology of the wound environment. Interactive dressings include hydrocolloids, hydrogels, alginates, foam dressings and antimicrobial dressings. 17, 20, 85Traditionally dry wound dressings are considered to be good for healing wounds i.e. the wound should be covered with gauze or left open. But it has been observed by Winter 191 that when wound is left open to air without any dressing, a scab i.e. a dry covering covers the wound and decreases the rate of epithelialization. On the other hand, if moist dressing is used in place of dry dressings scab will not form and rate of healing increases as moist dressings provide low oxygen tension which helps in wound healing, these dressings not only keep cells viable which enables them to release growth factors while maintaining contact between them and the healing tissues, but may also modulate or stimulate their proliferation, these dressings decrease the pain at rest, during ambulation and during dressing changes also moist environment all ows rapid and efficient delivery of any added antimicrobial agent thus prevent the wound from infection. So, the dressings that create and maintain a moist environment, however, are now considered to provide the optimal conditions for wound healing.2 Requirements of an ideal wound care systemThese characteristics should be present in the ideal wound care system (a) it should be capable of maintaining a high humidity at the wound site, (b) it should be non-toxic, (c) non-allergenic, (d) it can be removed without causing trauma to the wound, (e) it should pe impermeable to bacteria, (f) Thermally insulating, (g) it should be soft to touch, (h) it should allow proper gaseous exchange, (i) it should be free from particulate and toxic product, (j) promote tissue reconstructive memory processes and (k) it should be cost effective. 20, 165, 177Out of all the dressings hydrocolloids, alginates and hydrogels each one has its own advantages and limitations but hydrogels are best and have all the characteristics that are needed in an ideal wound dressing. All the above mentioned characteristics can be achieved in hydrogel wound dressings.3 Hydrogels for Wound Healing ApplicationsHydrogels are natural or synthetic cross-linked polymers used in a variety of medical and biomedical applications. Hydrogels consist of a matrix of insoluble polymers with up to 96% water content enabling them to donate water molecules to the wound surface and to maintain a moist environment at the wound bed. They are used in the construction of contact lenses, drug-delivery vehicles, wound dressings and as physiological electrodes or sensors. 17 Examples of hydrogel include Aquaform, Intrasite, GranuGel, Nu-Gel, Purilon, Sterigel.These also have the ability to absorb a degree of wound exudate. They transmit moisture vapour and oxygen, but their bacterial and fluid permeability is dependent on the type of secondary dressing used. 20 Hydrogels swell or shrink in aqueous solutions due to the associ ation, dissociation and binding of various ions to polymer chains. These systems may swell in water until an equilibrium state is reached and retain their original shape. The interactions responsible for water sorption by hydrogels include the process of hydration, which is connected to the presence of such chemical groups as -OH, -COOH, -CONH2, -CONH-, and -SO3H and the existence of capillary areas and differences in osmotic pressure. The forces that make hydrogel dissolution impossible are presence of covalent bonds between individual polymer chains, hydrophobic and electrostatic interactions. 46These are hydrophilic polymer networks which may absorb from 10-20% (an arbitrary lower limit) up to thousands of times their dry weight in water. These may be chemically stable or they may degrade and dissolve. They are called reversible, or physical gels when the networks are held together by molecular entanglements, and/or secondary forces including ionic, H-bonding or hydrophobic force s. 13, 14, 15 Hydrogels are called permanent or chemicalgels when they are covalently-crosslinked networks as shown in 1.Hydrogels can be made by irradiation, freeze-thawing or chemical methods. Out of all the methods, irradiation is considered as a suitable tool for the formation of hydrogels as in this method there is easy control of processing, no need of adding initiators or cross-linkers which are harmful, and have the possibility of formation and sterilization in one step. But as everything has its own advantages and disadvantages this method also has a disadvantage which is hydrogels formed by this method have poor mechanical strength. Nowadays, Freeze thawing technique is generally used to prepare hydrogels having good strength, stability and no crosslinkers and initiators. But the main disadvantage is that the prepared hydrogels have opaque appearance and limited swelling and thermal stability. 120In comparison to the traditional gauze therapy the application of a hydrogel seems to significantly stimulate wound healing. 11 Various natural and synthetic polymers having good biocompatibility are used to develop hydrogel wound dressing. These polymers include natural polymers such as alginate, chitosan, gelatin and collagen and synthetic polymers such as polyurethane, poly(ethylene glycol), polycaprolactone, poly vinyl pyrrolidone, poly(lactide-co-glycolide), polyacrylonitrile , poly(amino acid), etc. Table 1 below shows different hydrophilic polymers used to synthesize hydrogel matrices.Table 1 Hydrophilic polymers used to synthesize hydrogel matrices. 13Hydrogels may be classified as homopolymer hydrogels, copolymer hydrogels, multipolymer hydrogels, and interpenetrating polymeric hydrogels. Homopolymer hydrogels are crosslinked networks of one type of hydrophilic monomer unit, whereas copolymer hydrogels are produced by the crosslinking of two comonomer units, one of which must be hydrophilic. Multipolymer hydrogels are produced by the crosslinking of more than three monomers. Finally, interpenetrating polymeric hydrogels are produced by the swelling of a first network in a monomer and the reaction of the latter to form a second intermeshing network structure. 46, 47Also, it has been shown that the blending of a natural polymer with a synthetic polymer seems to be a good method for obtaining materials having required mechanical and thermal properties in comparison to pure components. It is also a simple method by which suitable shapes such as films, sponges and hydrogels can be obtained easily to realize a variety of biomedical devices.2 shows healing is faster with the hydrogel dressing than with the gauze dressing. Wound area covered by hydrogel decreases faster with increasing healing period. On the contrary, the wound covered by gauze dressing reduces by only half a percent even after 14 days. 1923.1 Natural HydrogelsNatural polymers, such as chitin, chitosan, alginate, collagen, elastin, genipin, gelatin, cellulose etc. hav e been used for dressing wounds because they play an important role in the healing process. 47Chitosan is a partially deacetylated form of chitin. Chitin as Beschitin, Unitika, is also commercially available as dressing in Japan. 28 But as far as chitosan is concerned it is biocompatible, biodegradable, haemostatic, fungistatic 54 and non-toxic and can be successfully used as gels, films, fibres etc. This polymer also show antibacterial properties and possess good wound healing properties. 60, 61, 62 It has many applications as wound dressing, drug delivery device and as scaffold for tissue engineering. 63, 64 Some of the examples of wound dressings are given below which use chitosan as one of the biomaterial.Asymmetric chitosan membranes have been developed by using immersion-precipitation phase-inversion method. 123, 124, 125 These asymmetric chitosan membranes are homogeneous and have porous structure. This membrane was prepared by preheating casted chitosan solution in oven for different time periods for dry phase separation and then immersed in to coagulant tank for wet phase separation and were subsequently freeze-dried. The skin layer acts as the rate controlling barrier for the release of drug and the porous layer provide mechanical support to the skin layer. The water vapor transmission rate, gas permeability, PBS solution absorption, in-vitro degradation, cell culture, bacterial penetration and wound healing test of this dressing were carried out. These membranes are effective in controlling evaporative water loss, showed excellent oxygen permeability and also antibacterial in nature. These are also found to be an urgent hemostat. In another study, silver sulphadiazine was incorporated as an antimicrobial agent to this asymmetric dressing. The release behaviour of both silver and sulphadiazine ions were studied and found to be significantly different from one another. Silver ions displayed a slow release behavior while sulphadiazine ions exhibited bu rst effect on first day of the drug release and then slowly tapered off. It is because of the interaction of silver with amino group of chitosan leading to its slow release throughout whereas, as the sulphadiazine ions were free to diffuse through the membrane to reach the wound site thus they showed a burst release. The membranes were further found effective against P. aerugniosa and S. aureus.In one of the papers, novel wound dressings were formed that composed of chitosan film and Minocycline Hydrochloride (MH) and commercial polyurethane film (Tegaderm) as a backing. It is also a useful formulation for the treatment of severe burn wounds. Water vapor and oxygen can permeate the Tegaderm film but water cannot. The tegaderm film support the polymer membrane. 126In one of the studies, a silver nanocrystalline chitosan (SNC) wound dressing composed of nano-silver and chitosan was constructed by self-assembly and nanotechnology and used for treating deep partial-thickness wounds. In this, sterility and pyrogen testing were performed to ensure biosafety. These dressings promote wound healing and combat infection, and also decrease the risk of silver absorption in comparison with silver sulphadiazine (SSD) dressings. 127There is also one more method of forming wound dressing composed of chitosan i.e. the formation of polyelectrolyte complex of gum kondagogu (GKG) and chitosan. This complex is formed by the electrostatic interaction between carboxyl group of gum and amine group of chitosan. This method is more advantageous as it avoids the use of organic solvents, chemical crosslinking agents and thus reduces the toxicity and undesirable side effects. In this, diclofenac sodium is used as model drug. The diclofenac loaded complex of gum kondagogu/ chitosan shows drug release which changes with change in pH. The drug release was higher at pH 6.8 as compared to pH 1.2, due to higher swelling of complex at higher pH. This holds a great potential as a natural polymer based delivery device for controlled delivery of drugs like diclofenac sodium for two reasons (i) to reduce dosing frequency and (ii) lower the gastric toxicity. 152Semi-interpenetrating polymer networks (SIPNs) composed of chitosan (CS) and poloxamer were prepared in order to improve the mechanical strength of CS. The WVTR was found to be 2508.265.7 gm2 day1, i.e. these can maintain a moist environment at wound site which enhance epithelial cell migration. Also, the in vitro assessment of SIPNs showed proper biodegradation and low cytotoxicity and in vivo is carried out on experimental full thickness wounds in a mouse model and found that the wounds covered with these were completely filled with new epithelium without any significant adverse reactions after 3 weeks.In one of the papers, a kind of surgical wound dressing, the chitosan-gelatin sponge wound dressing (CGSWD) having good antibacterial property is prepared. The in vitro test showed that the antibacterial effect of CGSWD on E. coli K88 is better than that of penicillin, and the effect on S. aureus is also better than that of cefradine. 137One more wound dressing consists of two separate layers were prepared in which the upper layer is a swellable hydrogel material which can absorb exudates and also serve as mechanical and microbial barrier while lower layer is a chitosan acetate foam incorporated with the anti-microbial agent chlorherxidine gluconate. 183 The antimicrobial activity is checked by the Bauer-Kirby Disk Diffusion Test, inhibition zones can be clearly seen around the discs of chitosan acetate foams incorporated with chlorhexidine gluconate, in culture plates inoculated with either Gram-negative or positive bacteria showing that the dressing is antimicrobial in nature.Blending is a convenient and effective method to improve physical and mechanical properties of hydrogels. So modification of chitosan is done by blending with other polymers like cellulose. 178 In this, E. coli and S. aureus were used as the test bacteria to examine the antibacterial properties of chitosan, cellulose and chitosan/cellulose blends. The numbers of colony of these bacteria formed on the test membranes are shown in s 5 and 6. It was noted that the numbers of colony of all test bacteria formed on the chitosan/cellulose blend membranes were decreased with the increase of chitosan concentration. These blends are more effective against E. coli than that of S. aureus, as indicated by the lower colony unit. Thus these dressings are suitable to use as an antimicrobial wound dressing.Chitosan due to its structural properties has the ability to heal wounds without scar formation. 198 Since chitosan is composed of D-glucosamine, which is also the component present in the disaccharide subunits of hyaluronic acid, chitosan tries to structurally mimic hyaluronic acid and exerts similar effects. 197 It has been known that the fetal wound healing takes place without fibrosis or scar formation due to the presence of hyaluronic acid. 199In one of the studies, Chitosan as a semi-permeable biological dressing maintains a moist environment and prevent the wound site from dehydration and contamination. In addition, digital colour separation analysis of donor site scars demonstrated an earlier return to normal skin colour at chitosan-treated areas as shown in 7. 196Collagen is also a biopolymer that is used as a polymer for making wound dressing and drug delivery devices as it is biocompatible and biocompatibility of a material applied to wound tissue is a prerequisite for optimal wound environment and facilitation of the healing processes. A new collagen dressing with gentamycin or amikacin was prepared in one of the research work and these follow the basic requirement of antibacterial bandages. The dressing is composed of two collagen biomaterialsmembrane and spongeboth possessing good tissue biocompatibility. These dressing released antibiotics slowly and show the antibacterial treatme nt in experimentally infected superficial wounds in mice. Thus, it can be used for the treatment of infected wounds in humans. 26As discussed previously that both chitosan and collagen are excellent materials that can be used as wound dressing materials. So it has been seen that if both are used simultaneously then what will be the effect. It is found that the wound dressings composed of chitosan crosslinked collagen sponge (CCCS) enhance the diabetic wound healing. Collagen crosslinked with chitosan showed several advantages required for wound dressing, including the uniform and porous ultrastructure, less water imbibition, small interval porosity, and high resistance to collagenase digestion and slow release of FGF from CCCS/FGF. 138Following moist healing concept, alginates which are able to absorb exudates from wound have become one of the most important materials for wound management. 52, 53, 54, 55, 56 In this particular field, the properties of alginate fibers are unparallele d in many respects. Alginate based products form a gel and effective in removing out of the wound on the contrary to traditional cotton and viscose fibres, which can entrap in the wound developing discomfort during dressing removal. 55 Also, the alginate fibres are non-toxic, non-carcinogenic, non-allergic, haemostatic, biocompatible, of reasonable strength, capable of being sterilized and easily processable. Sorbsan was first commercialized in 1981 and after that there were many dressings launched. The alginate fibers can be converted into wound dressings by using a number of textile processes. Because of its simplicity and also the high absorbency of the product, nonwoven is the main form of alginate wound dressings. 19The antimicrobial action of alginate dressing can be seen as in 8 which shows the antimicrobial action of silver containing alginate fibers against E. Coli. There was 100% reduction in bacteria count within 5 hr after the fibers were placed in contact with solutions containing the bacteria. Sorbsan alginate fibers showed some antimicrobial activity while AquacelTM (made of carboxymethyl cellulose), does not show any antimicrobial effect. 18Gelatin widely found in nature and is the major constituent of skin, bones, and connective tissue. Gelatin can easily be obtained by a controlled hydrolysis of the fibrous insoluble protein, collagen. 195 This is also used in number of biomedical applications like wound dressings. Hydrogel wound dressing from gelatin, oxidized alginate and borax were prepared and the composite matrix promotes wound healing because of alginate, has haemostatic effect of gelatin and is antiseptic because of borax. The water vapour transmission rate (WVTR) of the hydrogel was calculated and found to be 2686124 g/m2/day indicating that this hydrogel can maintain a proper fluid balance at the wound site which helps in cell migration. 2 shows the loss of water vapour with time through the hydrogel when placed in a moisture rich en vironment. 119Genipin has been used to crosslink chitosan membranes to control swelling ratio and mechanical properties. It increased its ultimate tensile strength but significantly reduced its strain-at-fracture and swelling ratio. It had significantly less cytotoxicity for human fibroblasts and slower degradation rate compared to the glutaraldehyde-crosslinked membrane. This genipin crosslinked chitosan membrane can be successfully used as a wound dressing. 132Bacterial cellulose is a natural polymer consisting of microfibrils containing glucan chains bound together by hydrogen bonds. Bacterial cellulose with chitosan combines properties such as bioactivity, biocompatibility, and biodegradability of the two biopolymers and form an ideal material for dressing wounds. 66, 67 These are antibacterial and scar preventive in nature too.Since natural polymers have been considered limited in their applications for wound-dressing materials as their low mechanical properties and shortage o f processing. So we move towards the synthetic polymers that can be used for wound healing applications.3.2 Synthetic HydrogelsSynthetic polymers are also being used successfully in biomedical applications as one of the materials because of their wide range of mechanical properties, suitability for easily forming into a variety of different shapes, and low production costs.In an ideal dressing both the characteristics i.e. antimicrobial ability and moist healing environment should be present, so in order to prevent the wound from dehydration and bacterial penetration a new dressing composed of polyurethane is designed in such a way that the upper layer of the dressing is microporous (pore size Polyvinyl pyrrolidone (PVP) is one of the most widely used synthetic polymers in medicine because of its solubility in water and its extremely low cytotoxicity. Hydrogels prepared by radiation crosslinking of an aqueous solution of polyvinyl pyrrolidone (PVP) have been used as wound dressing. 21 These are biocompatible, reduces pain, easily replacable, permeable to oxygen, maintain moist environment at the wound site.Polyvinyl alcohol (PVA) is a well-known polymer because it is biocompatible and have required mechanical properties and polyethylene oxide (PEO) is a hydrophilic semicrystalline polyether which is biocompatible, non toxic, non polar, non antigenic and non immunogenic and is highly desirable in most biomedical applications requiring contact with physiological fluids.A hydrogel composed of PEO for wound dressing is prepared and PVA is added to give toughness to the hydrogel by electron beam irradiation and found that these hydrogels showed satisfactory properties for wound dressing that has been evaluated by creating wound on the back of the marmots. 157 The hydrogel gives a wet environment to wounds which causes faster healing compared with the gauze dressing with a dry environment. The weight of the hydrogel increases quickly at the earlier stages, up to 4 d ays, due to absorption of effusion produced from the wound as shown in Table 2. After that, the production of effusion from the wound ceases and the weight of the hydrogel decreases due to evaporation of the water in the hydrogel. This means that the healing of wound proceeds smoothly with time. The hydrogel can be peeled off easily from the wound at the time of removal.Table 2 Absorption of effusion from wound of dressing during healing. 157The toughness of PEO hydrogel is improved by the addition of PVA and tensile strength is measured and found that as shown in 10 and 11, the tensile strength and elongation decrease with increasing dose because of the increase of crosslinking.Various synthetic polymers as discussed above are used for wound dressing applications. But the major problem with these materials is their biocompatibility characteristics are often unsatisfactory and their interaction with living tissues is a major problem. So a combination of both natural and synthetic po lymers is the better option to make a hydrogel having biocompatibility and desired mechanical strength.3.3 Blended hydrogelsSince both the natural and synthetic polymers have their own advantages and disadvantages so a combination of natural and synthetic polymers can endow the optimal properties necessary for wound repair. 47 The combination of natural and synthetic polymers is used in the biomedical, bioengineering and biotechnology field nowadays because of their great potential.A blended hydrogel composed of polyvinyl alcohol/polyvinyl pyrrolidone and charcoal were prepared by single freezing and thawing or two-step freezing and thawing and -ray irradiation and applied as wound dressing. It is found that the absorption of S. aureus and P. aeruginosa by charcoal/PVA/PVP hydrogels was larger than those by PVA/PVP hydrogels, this is due to the absorption and attachment capability of bacteria by charcoal, this can be shown in 12 given below. 22The most classical way of fabricating a CS based wound dressing has been to design an asymmetric composite structure. In this method, the Cotton fabric was coated with chitosan (CS) and polyethylene glycol (PEG) followed by freeze-drying. The outer dense layer helps in preventing the microbial passage across the dressing and provides a rate controlling barrier for water vapor permeation, while the inner porous layer provides a high surface area for the exudates absorption. For the absorption of wound exudates porosity is the prime requirement in a dressing. It has been found that these dressings have the porosity 54-70% and the pore size was in the range of 75-120m. 45 The increase in the PEG content in the blend composition led to an enhanced destabilization of pores, leading to an increase in the pore size with elongated morphology. There seems to be phase separation between the two components which is an important factor for the observed behavior of the porous structure. Cotton fabric has been used as the support laye r for the CS-PEG layer and leads to very thin and light weight structures. The structure of the dressing has been designed in such a way that it leads to the high porosity of the bulk structure. The thickness of CS coating plays an important role in the development of the porosity on the surface. The influence of the CS thickness on the surface morphology is presented in 13 given below.PEG addition to CS makes significant alteration in the surface morphology of this CS-PEG/cotton membrane (freeze-dried), henceforth known as CPC membrane. There is a distinct trend in the loss of inherent elongated porous structure in membranes and formation of the partially collapsed porosity takes place due to the PEG addition. This suggests that a very limited interaction between CS and PEG exists which is reflected in the observed surface morphology. It has been observed that higher the amount of PEG, the higher is the pore destabilization leading to larger pores. This is evident from the morpholo gy of the CPC membrane at 50% PEG-20 content as shown in 14.45On the above matrix, the addition of PVP and drug followed by coating on the cotton fabric and freeze drying of the coated matrix is also done. It has been found that the drug