A intervenção no cérebro e a possível influência no responder dos organismos têm sido alvo de diversas pesquisas que visam analisar tal relação. Deste modo, o presente estudo busca fornecer indicadores dos possíveis efeitos do fechamento das suturas cranianas sobre a aprendizagem discriminativa em esquemas de reforçamento. Para isso, serviram como sujeitos quatro ratos cirurgicamente intactos e nove submetidos a diferentes procedimentos cirúrgicos para o fechamento das suturas cranianas. Os sujeitos, com idades entre dois e oito dias de vida, foram submetidos a quatro fases experimentais em caixas de condicionamento operante. Na primeira fase, respostas de pressão à barra foram modeladas e, na seqüência, 60 respostas foram reforçadas em esquema de reforçamento contínuo (CRF) por três sessões consecutivas. Na segunda fase, o esquema de CRF foi substituído por esquemas de intervalos fixos (FI) com três valores aumentados gradualmente (FI 4 s, FI 8 s e FI 11 s). Na terceira fase, os sujeitos foram submetidos a um esquema múltiplo composto pelos componentes FI 11 s e Extinção (EXT), na presença e ausência de luz, respectivamente. Este treino discriminativo foi mantido até que ao menos 80% das pressões à barra ocorressem nos componentes de FI. Finalmente, na quarta fase, houve uma reversão das funções dos estímulos, de modo que a presença e a ausência de luz passaram a acompanhar, respectivamente, os componentes de EXT e FI. De modo geral, os resultados revelaram que os procedimentos empregados na constrição do desenvolvimento cerebral não produziram efeitos evidentes no comportamento dos ratos sob esquema de reforçamento, assim como na aprendizagem discriminativa e sua reversão / The intervention in the brain and the possible influence on the response of organisms has been the subject of several studies designed to examine this correlation. The aim of the present study is to provide indicators of the possible effects of the cranial sutures closure to the discriminative learning in reinforcement procedures. Four rats were used in a Non-Surgical condition group and another group was formed by nine rats that underwent various surgical procedures for the cranial sutures closure. The rats in the age between two and eight days underwent four experimental stages in operant conditioning boxes. In the first phase the bar press responses were modeled and, subsequently, 60 responses were reinforced under a scheme of continuous reinforcement (CRF) for three consecutive sessions. In the second phase, the scheme of CRF was replaced by schemes of fixed intervals (FI) with three values that were increased gradually (FI 4 s, FI 8 s FI s 11). In the third phase, the subjects underwent a multiple scheme with components FI 11 to Extinction (EXT) in the presence and absence of light, respectively. This discriminative training was continued until at least 80% of bar press response had occurred in the components of FI. Finally, in the fourth phase there was a reversal of the functions of the stimuli, so that the presence and absence of light started to follow, respectively, the FI and EXT components. The research result reveal that the procedures used in the constriction of the cerebral development did not produced evidences in the rats behavior under the reinforcement scheme, the discriminative learning and the reversion process

A intervenção no cérebro e a possível influência no responder dos organismos têm sido alvo de diversas pesquisas que visam analisar tal relação. Deste modo, o presente estudo busca fornecer indicadores dos possíveis efeitos do fechamento das suturas cranianas sobre a aprendizagem discriminativa em esquemas de reforçamento. Para isso, serviram como sujeitos quatro ratos cirurgicamente intactos e nove submetidos a diferentes procedimentos cirúrgicos para o fechamento das suturas cranianas. Os sujeitos, com idades entre dois e oito dias de vida, foram submetidos a quatro fases experimentais em caixas de condicionamento operante. Na primeira fase, respostas de pressão à barra foram modeladas e, na seqüência, 60 respostas foram reforçadas em esquema de reforçamento contínuo (CRF) por três sessões consecutivas. Na segunda fase, o esquema de CRF foi substituído por esquemas de intervalos fixos (FI) com três valores aumentados gradualmente (FI 4 s, FI 8 s e FI 11 s). Na terceira fase, os sujeitos foram submetidos a um esquema múltiplo composto pelos componentes FI 11 s e Extinção (EXT), na presença e ausência de luz, respectivamente. Este treino discriminativo foi mantido até que ao menos 80% das pressões à barra ocorressem nos componentes de FI. Finalmente, na quarta fase, houve uma reversão das funções dos estímulos, de modo que a presença e a ausência de luz passaram a acompanhar, respectivamente, os componentes de EXT e FI. De modo geral, os resultados revelaram que os procedimentos empregados na constrição do desenvolvimento cerebral não produziram efeitos evidentes no comportamento dos ratos sob esquema de reforçamento, assim como na aprendizagem discriminativa e sua reversão / The intervention in the brain and the possible influence on the response of organisms has been the subject of several studies designed to examine this correlation. The aim of the present study is to provide indicators of the possible effects of the cranial sutures closure to the discriminative learning in reinforcement procedures. Four rats were used in a Non-Surgical condition group and another group was formed by nine rats that underwent various surgical procedures for the cranial sutures closure. The rats in the age between two and eight days underwent four experimental stages in operant conditioning boxes. In the first phase the bar press responses were modeled and, subsequently, 60 responses were reinforced under a scheme of continuous reinforcement (CRF) for three consecutive sessions. In the second phase, the scheme of CRF was replaced by schemes of fixed intervals (FI) with three values that were increased gradually (FI 4 s, FI 8 s FI s 11). In the third phase, the subjects underwent a multiple scheme with components FI 11 to Extinction (EXT) in the presence and absence of light, respectively. This discriminative training was continued until at least 80% of bar press response had occurred in the components of FI. Finally, in the fourth phase there was a reversal of the functions of the stimuli, so that the presence and absence of light started to follow, respectively, the FI and EXT components. The research result reveal that the procedures used in the constriction of the cerebral development did not produced evidences in the rats behavior under the reinforcement scheme, the discriminative learning and the reversion process

<p><strong>Syfte</strong></p><p>Syftet med studien var att undersöka om det fanns skillnader mellan kvinnor som blivit suturerade med ett snabbabsorberande monofilt suturmaterial, Caprosyn® och ett multifilt suturmaterial, Polysorb® då det gällde kvinnans uppfattning om hur bristningen läkte åtta veckor postpartum.</p><p><strong>Urval</strong></p><p>Ett konsekutivt randomiserat urval. Fyrahundratvå kvinnor som fått en bristning vid förlossningen randomiserades till att sutureras med antingen Caprosyn® eller Polysorb®. Den slutgiltiga svarsfrekvensen var 67 %, det största bortfallet var på förlossningsavdelningen.</p><p><strong>Metod</strong></p><p>En experimentell kvantitativ studie. Två enkäter användes i studien, en som barnmorskan besvarade direkt efter förlossningen om bristningens art samt en till de medverkande kvinnorna åtta veckor postpartum.</p><p><strong>Resultat</strong></p><p>Inga skillnader fanns mellan suturmaterialen då det gäller kvinnornas smärta i underlivet, obehag i underlivet, återupptagande av sexualliv, samlagssmärta, amning eller hur många kvinnor som sökt sjukvård samt varför de sökt sjukvård åtta veckor postpartum. Fler positiva kommentarer gavs av barnmorskorna om Polysorb® än om Caprosyn®. Om kvinnan ammade delvis och hade samlagssmärta var denna smärta större än för de kvinnor som ammade helt. Ju lägre kvinnan skattade sin förlossningsupplevelse desto mer smärta hade kvinnan vid samlag åtta veckor postpartum.</p><p><strong>Slutsats</strong></p><p>De två studerade suturmaterialen skiljer sig inte åt enligt de deltagande kvinnornas upplevelse åtta veckor efter förlossningen. Däremot fanns ett samband mellan smärta i underlivet och upplevelse av förlossningen samt mellan hur mycket kvinnan ammade och samlagssmärta. Sammanfattningsvis kan barnmorskor inom förlossningsvården använda sig av båda materialen vid suturering av bristningar efter förlossning utan att det påverkar kvinnans hälsa negativt.</p>

Syfte Syftet med studien var att undersöka om det fanns skillnader mellan kvinnor som blivit suturerade med ett snabbabsorberande monofilt suturmaterial, Caprosyn® och ett multifilt suturmaterial, Polysorb® då det gällde kvinnans uppfattning om hur bristningen läkte åtta veckor postpartum. Urval Ett konsekutivt randomiserat urval. Fyrahundratvå kvinnor som fått en bristning vid förlossningen randomiserades till att sutureras med antingen Caprosyn® eller Polysorb®. Den slutgiltiga svarsfrekvensen var 67 %, det största bortfallet var på förlossningsavdelningen. Metod En experimentell kvantitativ studie. Två enkäter användes i studien, en som barnmorskan besvarade direkt efter förlossningen om bristningens art samt en till de medverkande kvinnorna åtta veckor postpartum. Resultat Inga skillnader fanns mellan suturmaterialen då det gäller kvinnornas smärta i underlivet, obehag i underlivet, återupptagande av sexualliv, samlagssmärta, amning eller hur många kvinnor som sökt sjukvård samt varför de sökt sjukvård åtta veckor postpartum. Fler positiva kommentarer gavs av barnmorskorna om Polysorb® än om Caprosyn®. Om kvinnan ammade delvis och hade samlagssmärta var denna smärta större än för de kvinnor som ammade helt. Ju lägre kvinnan skattade sin förlossningsupplevelse desto mer smärta hade kvinnan vid samlag åtta veckor postpartum. Slutsats De två studerade suturmaterialen skiljer sig inte åt enligt de deltagande kvinnornas upplevelse åtta veckor efter förlossningen. Däremot fanns ett samband mellan smärta i underlivet och upplevelse av förlossningen samt mellan hur mycket kvinnan ammade och samlagssmärta. Sammanfattningsvis kan barnmorskor inom förlossningsvården använda sig av båda materialen vid suturering av bristningar efter förlossning utan att det påverkar kvinnans hälsa negativt.

Craniosynostosis is the premature fusion of one or more cranial sutures in the developing skull. If left untreated, craniosynostosis can result in developmental delays, blindness, deafness, and other impairments resulting from an increase in the intracranial pressure. In many cases, the treatment consists of complex calvarial vault reconstruction with the hope of restoring a normal skull appearance and volume. Re-synostosis, the premature re-closure following surgery, occurs in up to 40% children who undergo surgery. If this occurs, a second surgery is needed to remove portions of the fused skull in an attempt to correct the deformities and/or relieve an increase in intracranial pressure. These subsequent surgeries are associated with an incredibly high incidence of life threatening complications. To address this unmet clinical need we have developed strategies to delay the post-operative bone growth in a clinically relevant murine model of re-synostosis. The overall objective of this thesis was to develop a hydrogel based therapy to delay rapid bone regeneration in a murine model of re-synostosis. The overall hypothesis was that delivery of key BMP inhibitors involved in regulating normal suture development and regeneration will delay the rapid bone growth that in seen in a pediatric murine model of re-synostosis. The overall approach is to use micro-computed tomography (µCT) to determine the time course of suture fusion and to identify genes associated with key developmental time points, to develop a pediatric specific mouse model that displays rapid re-synostosis, and lastly to develop a hydrogel based therapy to delay the re-synostosis of this cranial defect.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 4 uppsatser.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-17T12:59:30Z No. of bitstreams: 1 RAFAELLA LIMA DE MENEZES - DISSERTAÇÃO PPG-CEMat 2014..pdf: 7131098 bytes, checksum: 662a27be023a1d5cf9b17d3f230efb5c (MD5) / Made available in DSpace on 2018-04-17T12:59:30Z (GMT). No. of bitstreams: 1 RAFAELLA LIMA DE MENEZES - DISSERTAÇÃO PPG-CEMat 2014..pdf: 7131098 bytes, checksum: 662a27be023a1d5cf9b17d3f230efb5c (MD5) Previous issue date: 2014-08-28 / A quitina é o segundo polissacarídeo natural mais abundante depois da celulose. É biodegradável, não tóxico e encontrado em ambiente marinho como microfibrilas cristalinas ordenadas formando componentes no exoesqueleto de artrópodes e nas paredes celulares de alguns fungos e bactérias. Propriedades como a biocompatibilidade, biodegradabilidade e baixa toxicidade exibida pelas fibras de quitina combinadas com propriedades mecânicas adequadas torna estas, candidatas para aplicações como material de sutura. Este trabalho tem como objetivo a obtenção e caracterização físico-química e estrutural, de fibras de quitina para aplicação como fios de sutura, extraída a partir de exoesqueletos de camarões (espécie: de Litopenaeus vannamei). Esta pesquisa foi dividida em duas metodologias para um melhor entendimento, sendo, portanto composto do processo de extração da quitina seguido pelo processo de obtenção das fibras. As concentrações de quitina utilizadas na formação das fibras foram de 0,5%, 0, 85%, 1%. Dissolvidas no solvente DMAc/LiCl2 (5%) e coaguladas em etanol (30%), acetona (70%), água destilada (100%), CaCl2 (2%). O pó de quitina obtido na primeira etapa desta pesquisa foi caracterizado através das técnicas de difração de raios-X (XRD) e espectroscopia de infravermelho com transformada de Fourier (FTIR). Através do DRX foi possível identificar o tipo de quitina obtida como a alfa quitina, isto confirma a estrutura da quitina presente na casca de camarão, o FTIR revelou a ausência de proteína, confirmando que a quitina obtida pode ser utilizada como um biomaterial. As fibras obtidas na segunda etapa desta pesquisa foram caracterizadas por microscopia eletrônica de varredura SEM/EDS, o qual revelou a influência dos banhos de coagulação no diâmetro das fibras, o aumento do pH no banho de coagulação levou a uma neutralização mais rápida das fibras que quitina, ocorrendo um fenômeno conhecido como shrink nas fibras. Testes de intumescimento revelaram a influência dos banhos de coagulação utilizados, as fibras coaguladas com solventes orgânicos, possuíram um menor grau de intumescimento, quando comparadas com as fibras coaguladas em solventes aquosos. Para os ensaios mecânicos de tração têm-se que as fibras na concentração de 0,5% de quitina devido a uma melhor homogeneidade da solução, possuíam propriedades mecânicas mais adequadas quando comparadas com as outras fibras produzidas. Os resultados de viabilidade celular das fibras apresentaram percentagem superior a 90%, evidenciado a ausência do solvente nas fibras produzidas. Através dos ensaios de biodegradação é possível observar uma perda de massa nas fibras somente a partir do quinto dia. Os resultados obtidos demonstram que o objetivo da pesquisa foi alcançado, de produzir fibras de quitina a partir da casca do camarão, além de indicarem a possível aplicação deste material como um fio de sutura. / Chitin is the second most abundant natural polysaccharide after cellulose It is biodegradable, non-toxic and found in the marine environment as ordered crystalline microfibrils forming components in the arthropods exoskeleton and the cell walls of fungi and bacteria. Properties like biocompatibility, biodegradability, low toxicity exhibited by chitin fibers combined with adequate mechanical properties make them candidates for applications such as suture material. This work aims, obtaining and characterize through a physicochemical and structural characterization of chitin fibers for their use as sutures, extracted from the shrimp exoskeletons (species: Litopenaeus vannamei). This research was divided into two methodologies for a better understanding, is composed by the chitin extraction process followed by the fiber process obtention. The chitin concentration used in the fibers formation were 0.5% 0 85% 1%. Dissolved in DMAc / LiCl2 (5%) solvent and coagulated in ethanol (30%), acetone (70%), distilled water (100%), CaCl2 (2%). The chitin powder obtained in the first step of this study was characterized using the X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. By XRD it was possible to identify the chitin obtained as alpha chitin, this confirms the chitin structure present in the shrimp shell, the FTIR revealed the absence of protein, confirming that the chitin obtained can be used as a biomaterial. The fibers obtained in the second step of this study were characterized by SEM / EDS, which revealed the influence of coagulation baths in the fiber diameter, the increased pH in the coagulation bath led to a more rapid neutralization of the chitin fibers, a phenomenon known as shrink. Swelling tests revealed the influence of the coagulation baths, the fibers coagulated with organic solvent, owned a lower swelling degree compared to the fibers coagulated in aqueous solvents. For the tensile test the fibers with a chitin concentration of 0.5% due to a better solution homogeneity had more adequate mechanical properties, compared to the other fibers produced. The results for cell viability showed a percentage of 90%, evidencing the solvent absence in the fiber produced. Through biodegradation tests is possible to observe a mass loss in the fibers only from the fifth day. The results demonstrated that the objective was achieved, to produce chitin fibers from the shell of shrimps, and indicate a possible application of this material as a suture wire.

Transition analysis transforms skeletal traits with an invariant, unidirectional series of stages into a likelihood function with a maximum likelihood value and a 95% confidence interval. Boldsen et al. used transition analysis to develop an adult age estimation method employing components of the cranial sutures, pubic symphysis and ilial portion of the sacroiliac joint, used either in combination or individually. This validation study aimed to use the 36 transition analysis numerical, categorical scores for the anatomical features in conjunction with the ADBOU computer program to assess the accuracy and precision of the age estimates for 149 black individuals from the Pretoria Bone Collection. In addition, the effect of observer variability in scoring of these traits was assessed. Six age estimations were generated by the ADBOU computer program using 1) the cranial sutures only, 2) the pubic symphysis only, 3) the auricular surface of the ilium only, 4) all three features combined, 5) all three features combined and modified by a forensic prior distribution and 6) all three features combined and modified by an archaeological prior distribution. The six point estimate categories, calculated from the maximum likelihood values, were evaluated for accuracy using mean absolute values. The 95% confidence intervals were evaluated for range width and accuracy. Cohen’s Kappa statistics were used to analyse repeatability of the scoring procedure through inter- and intra-observer agreement and Kruskal-Wallis ANOVA statistics to determine the effect of observer differences on the final age estimates. The usefulness of the age ranges were diminished by large widths encompassing up to 95 years. The accuracy for the point estimates fared better for the combined skeletal indicators and overall accuracy was improved by using the archaeological prior distribution. The archaeological prior distribution was also responsible for narrowing the age ranges, especially in the older ages (over 70 years). Age estimates did not differ significantly when using inter- and intra-observer scores, but experience with the method did seem to improve results. Overall, age ranges were too wide, but accuracy could potentially be improved by adding more skeletal components to the method and using a population-specific prior distribution. The method would need considerable adjustments to make it usable in a South African setting. / Dissertation (MSc)--University of Pretoria, 2014. / tm2015 / Anatomy / MSc / Unrestricted

Ökningen av världspopulationen har orsakat en ökad avfallsgenerering. Avfallet kan innehålla betydelsefulla ämnen, vilka kan användas som råvaror i många olika material och för olika ändamål. Därför har omfattande forskning genomförts för att ta till vara på avfall som orsakar miljöföroreningar och ur dessa utveckla mer hållbara och biologiskt nedbrytbara material. Exempel på detta är fibrer och textilier framställda av polysackaridmaterial, särskilt från kitin och kitosan, som finns tillgängliga som biprodukt från såväl skaldjur som insekter och cellväggar från svampar. Kitin är efter cellulosa den vanligaste aminopolysackarid-polymeren som har en liknande struktur, medan kitosan är den deacetylerade formen av kitin som är den mest välkända och det viktigaste derivatet av kitin. Kitosan kan framställas från kitin genom antingen kemisk deacetylering eller enzymatiska beredningar, men för kommersiell skala idag, är produktion av kitosan med kemisk metod som deacetylering av kitin med en alkali såsom NaOH, mer lämplig och att föredra. Både kitin och kitosan är biobaserade material som har speciella egenskaper såsom hög specifik styvhet och hållfasthet, samtidigt som biologisk nedbrytbarhet är möjlig. Dessutom förekommer materialen rikligt i naturen, vilket gör dem till passande och konkurrenskraftiga ersättare till traditionella fibrer. Textilier är en stor källa till koldioxidutsläpp på grund av massiv global produktion och att även icke-nedbrytbara fibrer i vissa fall används i produktionen. Fibrer är den elementära enheten i textilier förutom bomull, som traditionellt används för textilproduktion. Det finns olika typer av fibrer som vanligtvis delas in i syntet- och biobaserade fibrer härrörande från förnybara resurser. Dessa förnybara fibrer har skapat ett stort intresse från världens textiltillverkare för att ställa om sin produktion och exempelvis producera gasbindor med återvinningsbara och biologiskt nedbrytbara material. Användningen av kitin och kitosan i textilindustrin är mycket intressant och viktig, dels på grund av deras mångsidighet och stora överflöd i naturen, dels då materialen annars anses vara spill eller restprodukter utan signifikant betydelse. Syftet med denna avhandling var att göra en litteraturöversikt om metoder för produktion av fibrer och textilier från kitin och kitosan, samt att undersöka hur de kan användas och dess miljövänliga aspekter. I denna avhandling har olika metoder baserade på många undersökningar och experiment introducerats, för att förstå och utvärdera möjliga processer för bildning av kitin- och kitosanfibrer. Dessutom har egenskaperna hos de framtagna fibrerna såsom draghållfasthet och töjning undersökts. För kitinproduktion har fem olika metoder studerats med användning av olika lösningsmedel av joniska vätskor såsom 1-etyl-3-metylimidazoliumacetat [C2mim] OAc, 1-butyl-3-metylimidazoliumklorid [C4mim] Cl och 1-etyl-3-metylimidazoliumklorid [C2mim] Cl, triklorättiksyra (TCA) och metylenklorid, en kombination av TCA, klorhydrat och metylenklorid, en blandning av myrsyra (FA), diklorättiksyra (DCA) och isopropyleter (iPE), liksom en direkt upplösning i NaOH/tiourea/urea. Produktion av nanofibrer från krabbskal, räkskal, kommersiella kitinpulver och svamp har undersökts, samt sårförband som en icke-vävd textil, genom att undersöka två olika produktionsmetoder. Många studier på kitosanproduktion har listats med fokus på typen av spinnteknik såsom våtspinning med användning av en cellulosa/kitosan-kompositlösning samt fibrer bildade av myrsyramodifierad kitosan. Dessutom listas olika typer av tekniker för torrspinning, torrstråle-våtspinning och elektrospinning. Slutligen har sårförbandsprocessen med användning av icke-vävda textilier av chitosan/hyaluronan också inkluderats. Sammanfattningsvis är produktion av textilfibrer med kitin och kitosan möjlig och kan göras på olika sätt. På grund av deras egenskaper och antimikrobiella effekter blir de intressanta alternativ till medicinska tillämpningar såsom suturer, sårförband, vävnadsteknik och antimikrobiellt medel. I likhet med andra material har kitin och kitosan fördelar, men även vissa nackdelar såsom svag och låg draghållfasthet hos de framtagna fibrerna och att de är delvis lösliga i substanser med pH under 5,5. Produktion av fibrer och textilier baserade på kitin och kitosan är fortfarande en utmaning på grund av de många modifieringssteg som krävs. Bland annat måste man ta hänsyn till lösningsmedlet som används för upplösning, välja rätt spinnteknik samt att använda ett lämpligt koagulationsbad följt av en flerstegs tvätt- och torkningsprocess. Dessa metoder hjälper till för att uppnå önskade fibrer med en mycket god kvalitet. För att uppnå en kostnadseffektiv, miljövänlig, konkurrenskraftig och storskalig textilproduktion - särskilt inom klädindustrin - krävs därför framtida arbete för att förfina och utveckla tekniken. / The growing of the world population caused an increase in waste generation which may contain high-value substances that can be used as raw materials in many applications. Therefore, tremendous research has been done towards the conversion of those wastes, that cause environmental pollution, in more sustainable and biodegradable materials. Part of these materials are fibers and textiles produced from polysaccharide materials especially from chitin and chitosan. Both chitin and chitosan are available as a by-product of seafood as well as in insects and cell walls of fungi, and can be used in many different applications. Chitin is the most abundant amino polysaccharide polymer after cellulose which has a very similar structure to cellulose, while chitosan is the deacylated form of chitin and it is the well-known and the most important derivative of chitin. Chitosan can be produced from chitin by either chemical deacetylation or enzymatic preparations. However, at commercial scale nowadays, the production of chitosan by chemical method like deacetylation of chitin with an alkali such as NaOH, is more suitable and preferable. Both chitin and chitosan are bio-based materials that have special properties such as high specific stiffness and strength, they are biodegradable and plentifully available in the nature, which make them an active competitive to the production of the synthetic fibers. Textiles are a big source for carbon emissions because of their large volume production and origin, in some cases, from non-biodegradable fibers. Fibers are the elementary units of textiles besides cotton that is traditionally used for textile production. There are different types of fibers that are usually divided into synthetic- and bio-based fibers derived from renewable resources which are getting a lot of interest in order to produce more biodegradable materials. Therefore, using chitin and chitosan in the textile industry is very important due to their versatility and large abundancy in nature. Additionally, they are biodegradable, biocompatible, non-toxic, and they are essentially able to form fibers and textiles. The purpose of this thesis was to make a literature review about the methods for the production of fibers and textiles from chitin and chitosan, including their applications and their environmentally friendly aspects. Different methods have been introduced in this thesis based on many researches and experiments in order to understand and evaluate which are the possible processes for chitin and chitosan fiber formation as well as the properties of the resulted fibers such as tensile strength and elongation. For fiber production from chitin has been studied by using different solvents including ionic liquids such as 1-ethyl-3-methylimidazolium acetate [C2mim]OAc, 1-butyl-3-methylimidazolium chloride [C4mim]Cl and 1-ethyl-3-methylimidazolium chloride [C2mim]Cl, trichloroacetic acid (TCA) and methylene chloride, a combination of TCA, chloral hydrate and methylene chloride, a mixture of formic acid (FA), dichloroacetic acid (DCA) and isopropyl ether (iPE), as well as a direct dissolution in NaOH/ thiourea/ urea. Additionally, nanofibers production from crab shells, prawn shells, shrimp shells, commercial chitin powders and mushrooms has been studied. Finally, wound dressing which is one of the nonwoven fabrics applications is introduced by referring to two methods of production. For fiber production from chitosan, many studies have been listed focusing on the type of the spinning technique such as wet spinning by using a cellulose/chitosan composite solution as well as fibers formed from formic acid modified chitosan. In addition, dry spinning, dry-jet wet spinning and electrospinning techniques have been studied. The wound dressing process by using chitosan/hyaluronan nonwoven fabrics has also been introduced. In conclusion, the production of textile fibers made of chitin and chitosan is possible and can be made in different ways. And because of their properties as biocompatibility, nontoxicity as well as their antimicrobial effects, they become interesting candidates for medical applications such as in sutures, wound dressing, tissue engineering and as antimicrobial agent. Similar to other manufactural industries, the production of fibers and textiles from chitin and chitosan have many advantages such as good values for dry tensile strength and elongation at break, antimicrobial activity and many more. At the same time, this production has some disadvantages such as the weak and low tensile strength of the resulted fibers and that they are partially soluble at pH below 5.5. Producing fibers and textiles based on chitin and chitosan is still a challenge because of the many modification steps that are needed. The modifications include the solvent used for dissolution, choosing the proper spinning technique as well as using an appropriate coagulation bath followed by the conditions of washing and drying steps. Thus, the desired fibers with a very good quality mentioned before would be achieved. Therefore, a lot of future work is needed in this manner because the intention is to achieve a cost-effective, environmentally friendly and a competitive technology for the large scale textile production especially in clothing industries.

Thesis (MMed)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: OBJECTIVE The purpose of the study is to establish the best method of wound closure with regards to patient satisfaction that includes wound cosmesis and pain. STUDY DESIGN One hundred patients were randomised to two groups for the closure of abdominal wounds; one group had subcuticular sutures and the other staples. They were followed up at 6 weeks. The primary outcome was patient satisfaction that includes wound cosmesis and pain. The secondary outcome was wound complications. RESULTS In women undergoing abdominal operations there was no difference as regards the patient satisfaction in both the groups, subcuticular sutures n= 51 vs. staples n=49 (P = 0.76). CONCLUSION Our study suggest that there is no statistically significant difference in the methods of wound closure, subcuticular sutures vs. staples as regards the patient satisfaction and the appearance of the scar leaving the decision in the hands of the surgeon to choose any method according to their own personnel preference and availability. / AFRIKAANSE OPSOMMING: NAVORSINGSDOEL Die fokus van hierdie projek is om vas te stel wat die beste metode van vel sluiting is ten opsigte van pasiënt bevrediging ten opsigte van wond voorkoms en pyn. METODES Een honderd pasiënte is ewekansig verdeel tot velsluiting van abdominale wonde met subkutane oplosbare steke of velhakies. Evaluasie is gedoen tydens ‘n opvolg besoek 6 weke na chirurgie. Die hoof uitkoms was pasiënt tevredenheid. Evaluasie van wond komplikasies is as sekondêre uitkoms beskryf. RESULTATE Vroulike pasiënte wat ‘n Pfannenstiel velinsnyding ondergaan toon geen verskil in pasiënt tevredenheid wanneer subkutane steke (n = 51) met velhakies (n = 49) vergelyk word nie (P = 0.76). SAMEVATTING Ons projek het geen statisties beduidende verskil getoon ten opsigte van pasiënt tevredenheid of wond voorkoms met 6 weke opvolg nie. Dit laat dus die besluit by die chirurg om metode van velsluiting te kies afhangend van voorkeur en toerusting beskikbaarheid.