• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 931
  • 574
  • 148
  • 126
  • 119
  • 59
  • 31
  • 28
  • 13
  • 12
  • 10
  • 9
  • 8
  • 8
  • 8
  • Tagged with
  • 2418
  • 480
  • 452
  • 395
  • 251
  • 203
  • 190
  • 169
  • 164
  • 162
  • 155
  • 151
  • 123
  • 122
  • 116
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
441

Biodegradable microspheres for controlled drug/cell delivery and tissue engineering

Zhang, Hao January 2012 (has links)
The synthetic biodegradable polymer poly(lactide-co-glycolide) (PLGA) has been widely explored as substrate biomaterials for controlled drug delivery and tissue engineering. ECM component heparin and bone mineral hydroxyapatite (HA) are attractive biomaterials which can functionalize the PLGA surface to improve cell cell response and to bring in the dual growth factor delivery, because heparin and HA both can improve cell responses and bind with various proteins. To combine the osteoconductivity of HA and the controlled drug release of PLGA microspheres, HA coated PLGA microspheres were developed by a 3 hour rapid HA precipitation on the PLGA microsphere surface. Effects of various fabrication parameters on microsphere and HA coating morphology were evaluated. This core-shell composite worked as a dual drug delivery device and demonstrated better cell cell response than PLGA microspheres without HA coating. Three different methods, including osmogen, extractable porogen and gas-foaming porogen, were evaluated to fabricate porous microspheres as injectable cell scaffolds in the tissue engineering. The gas-foaming method produced covered porous PLGA microspheres, on which a skin layer covered all the surface pores. The skin layer was hydrolysed by NaOH to control the surface porosity. The modified open porous microspheres have large continued surface areas between pores, which provided more continued areas for cell adhesion. The porous microspheres with controllable surface porosity and large surface continuity between pores could be novel injectable cell scaffolds. Heparin was immobilized on the open porous PLGA microspheres by a facile layer-by-layer assemble to combine the advantages of porous structure and the protein binding from heparin. The heparin-coated porous microspheres promoted cell adhesion, spreading, proliferation and osteogenic differentiation. Growth factor-like protein lactoferrin was immobilized on the heparin coated porous microspheres, which further enhanced MG-63 proliferation and osteogenic differentiation. The heparin-coated porous microspheres are promising multi-functional devices for controlled drug delivery and injectable cell delivery.
442

Cue-Controlled Relaxation: Saving Time Versus Efficacy

Todd, John Bruce 08 1900 (has links)
Cue-controlled relaxation is looked at to determine whether a component is efficacious as the entire procedure. Subjects were 40 male and 40 female undergraduates. Subjects were randomly assigned to one of four conditions: cue-controlled relaxation, progressive muscle relaxation, breathing exercises with a paired. cue word, on a presentation of the cue word without being paired. It was hypothesized that cue-controlled relaxation would be superior to a component of cue-controlled relaxation. It was determined that cue-controlled relaxation is not more efficacious than a particular component. Data suggests the majority of anxiety reduction takes place when the treatment focuses on the same modality from which the subject receives the most information about their anxiety. Implications and suggestions for further research are presented.
443

Microgels for oral delivery of therapeutic proteins

Belooussov, Anton January 2008 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
444

Efficacy of a Self-forgiveness Workbook: A Randomized Controlled Trial with University Students

Griffin, Brandon J. 28 March 2014 (has links)
Insofar as forgiveness of oneself enables one to responsibly manage the consequences of wrongdoing, the practice of self-forgiveness may be essential to the preservation of one’s physical, psychological, relational, and spiritual health. In the present thesis, an intervention wait-list design was employed to investigate the efficacy of a 6-hour self-directed workbook designed to promote self-forgiveness. University students (N = 204) who reported perpetrating an interpersonal offense and who experienced some sense of remorse were randomly assigned to either an immediate treatment or wait-list control condition, and assessments were administered on three occasions. Participants’ self-forgiveness ratings increased in conjunction with completion of the workbook, and the effect of treatment depended upon self-administered dose and baseline levels of dispositional self-compassion in some cases. In summary, the workbook appeared to facilitate the process of responsible self-forgiveness among perpetrators of interpersonal wrongdoing, though replication trials are needed in which lower rates of attrition reduce the possibility of biased results.
445

Development of nanostructured hydrogel for spatial and temporal controlled release of active compounds

Alsharif, Shaker 02 1900 (has links)
L’utilisation de nanovecteurs pour la livraison contrôlée de principes actifs est un concept commun de nous jours. Les systèmes de livraison actuels présentent encore cependant des limites au niveau du taux de relargage des principes actifs ainsi que de la stabilité des transporteurs. Les systèmes composés à la fois de nanovecteurs (liposomes, microgels et nanogels) et d’hydrogels peuvent cependant permettre de résoudre ces problèmes. Dans cette étude, nous avons développé un système de livraison contrôlé se basant sur l’incorporation d’un nanovecteur dans une matrice hydrogel dans le but de combler les lacunes des systèmes se basant sur un vecteur uniquement. Une telle combinaison pourrait permettre un contrôle accru du relargage par stabilisation réciproque. Plus spécifiquement, nous avons développé un hydrogel structuré intégrant des liposomes, microgels et nanogels séparément chargés en principes actifs modèles potentiellement relargués de manière contrôlé. Ce contrôle a été obtenu par la modification de différents paramètres tels que la température ainsi que la composition et la concentration en nanovecteurs. Nous avons comparé la capacité de chargement et la cinétique de relargage de la sulforhodamine B et de la rhodamine 6G en utilisant des liposomes de DOPC et DPPC à différents ratios, des nanogels de chitosan/acide hyaluronique et des microgels de N-isopropylacrylamide (NIPAM) à différents ratios d’acide méthacrylique, incorporés dans un hydrogel modèle d’acrylamide. Les liposomes présentaient des capacités de chargement modérés avec un relargage prolongé sur plus de dix jours alors que les nanogels présentaient des capacités de chargement plus élevées mais une cinétique de relargage plus rapide avec un épuisement de la cargaison en deux jours. Comparativement, les microgels relarguaient complétement leur contenu en un jour. Malgré une cinétique de relargage plus rapide, les microgels ont démontré la possibilité de contrôler finement le chargement en principe actif. Ce contrôle peut être atteint par la modification des propriétés structurelles ou en changeant le milieu d’incubation, comme l’a montré la corrélation avec les isothermes de Langmuir. Chaque système développé a démontré un potentiel contrôle du taux de relargage, ce qui en fait des candidats pour des investigations futures. / Controlled delivery of active compounds using nanoscale carriers is nowadays a common concept, but there are still limitations in current delivery systems related to active compound release rate and nanocarriers stability. To address these limitations, delivery systems can be made to incorporate both nanocarriers (liposomes, microgels and nanogels) and hydrogels. In this study, we have developed controlled delivery systems by combining different carriers in order to overcome deficiencies observed in systems using only one type of carrier. Such a combination could lead to an enhanced controlled release delivery system through synergistic stabilization. More specifically, we created a structured hydrogel embedded with either liposomes, microgels, or nanogels, each loaded with model active compounds that would be released in a controlled fashion by manipulating the temperature of release medium and nanocarriers composition and concentration. We compared drug loading and release kinetics of sulforhodamine B from liposomes (composed of DOPC and DPPC at different ratios) and nanogels (chitosan/hyaluronic acid) embedded in acrylamide hydrogels. We also compared drug loading and release kinetics of rhodamine 6G from microgels of N-isopropylacrylamide (NIPAM) with different ratios of methacrylic acid embedded in acrylamide hydrogel. Liposomes demonstrated a moderate drug loading capacity with sustained release for over ten days, while nanogels showed high drug loading but faster release kinetics, exhausting their contents within two days. Comparatively, microgels completely released their content within a day. Despite their faster release kinetics, microgels have shown the capacity to be finely tuned for efficient drug loading. The Langmuir isotherms indicated that it can be achieved by altering their structural properties or by changing their incubation medium. Each developed system has demonstrated a potential in controlling the release rate, which makes them candidates for further investigations in the future.
446

Redefining (interior)scapes: integrating the natural and built environment

Fakhraldeen, Sukaina January 1900 (has links)
Master of Landscape Architecture / Department of Landscape Architecture, Regional and Community Planning / Mary Catherine (Katie) Kingery-Page / In the temperate Midwest, interiorscapes are seldom a feature of public schools. The interior spaces of school environments tend to be dull, uninspiring, and do very little to nurture the wellbeing and needs of students. Interiorscapes can greatly influence the overall productivity of users by creating healthy, pleasant environments. Schools fail to create richer indoor environments for a number of reasons, such as lack of resources as well as knowledge about the design, implementation and benefits of interiorscapes. In addition students today “are not the outdoor-living [children] they were 100 years ago, and as much as 90% of [their] time may be spent indoors” (Manaker, 2). Healthy and stimulating school environments have the potential to enhance students’ productivity and creativity. Therefore the question at hand is: how can a Manhattan Kansas’ high school integrate the natural and built environment to create richer interior spaces? In this Master’s report, I explore the potential benefits of designing an interiorscape that integrates the natural and built environments within a school setting. Using Manhattan High School West Campus as the project site, I analyzed the effect and design of existing interiors on students through passive observation. Numerous research precedents identified valuable information on design processes and methodologies for designing interiorscapes and evaluating user interaction with existing places. Following a thorough analysis of the typology and characteristics of each precedent, I considered unique facets that were directly applicable to my project site. I then went to test the aspects selected from these precedents by incorporating them into the design for the selected project site; north courtyard and adjacent interior dining space. Based upon the precedent research and literature review, design goals and objectives evolved. The end product is a schematic design for Manhattan’s High School cafeteria area and north courtyard. The plan encompasses desired characteristics of an interiorscape and needs of its potential users. Ultimately, this proposal presents ideas for ways of implementing interiorscapes to enhance the overall productivity of users, while simultaneously strengthening the relationship between the natural and built environments.
447

Effect of post-harvest treatment on ripening and quality of tomato fruit using ozone : application of different ozone doses as controlled atmosphere storage for delay ripening and maintaining the quality of tomatoes and effect of ozone on antioxidant and sugar compounds at different stages of tomato fruit ripening

Shalluf, Milad A. January 2010 (has links)
Tomatoes are widely produced and consumed due to their nutritional content and versatility. However, the tomato is a soft fruit liable to damage and flavour deterioration. Hence, the main challenge for the tomato producing industry is to prevent the high loss incurred during harvest, handling and transportation of the crops. The objective of this study was to investigate the overall nutritional implication of controlled storage of tomatoes using ozone on the ripening process and the basic nutritional components of tomatoes. This investigation was also designed to focus on the effect of different ozone doses on the basic components and properties (carotenoids, ascorbic acid, total antioxidant activity and soluble sugars content) of the quality and dynamic maturity of tomatoes. Green tomatoes (Rio Grande) were treated in glass chambers with ozone enriched air [(air + 2, 7 and 21 mg O3/g tomato) and control (air only)] under humidity and temperature of 90-95% and 14-17 oC respectively. Tomatoes were sampled after 14 days of ozone treatment in the storage chamber and analyzed for different quality parameters (appearance, weight loss, Total Soluble Solids (TSS), titratable acidity, total ascorbic acid and carotene) of the ripening. The variety Elegance tomatoes were selected and the fruits were graded by colour and subjected to treatment with ozone (in doses 0 (clean air), 0.25, 0.50, and1.00 mg O3/g tomatoes) during storage for 6 days under the same humidity and temperature conditions. The fruits were analysed for carotenoids, ascorbic acid content, total antioxidant activity and soluble sugars. Analysis of the fruits clearly showed that ozone significantly delayed the development of colour on the surface, particularly in the low doses, and caused black spots on the surface of the tomatoes, particularly in higher ozone doses. Ozone did not affect the ascorbic acid and titratable acidity content. However ozone did reduce the Total Soluble Solids (TSS) by about 10% at the lowest ozone dose. A high inhibition of accumulation of carotenoids, particularly at low dose, of the tomatoes (Rio Grande) was also observed. Tomatoes (Elegance) under ozone treatments contained higher ß-carotene than those under the control treatment and lycopene content increased during storage in the red stage of tomato fruits. Ascorbic acid (AsA), dehydroascorbic acid (DHA) and the total of AsA and DHA concentrations, and ratios of redox (ASA/ (ASA + DHA) and DHA/AsA in pericarp and pulp of tomatoes tissue, did not show clear differences between the different treatments. The concentrations of the glucose and fructose increased in the tomatoes which were subjected to ozone treatments. Results from this study show that controlled atmosphere storage of tomatoes using ozone is a viable technique which warrants further study.
448

Copolymères diblocs amphiphiles et thermostimulables : synthèse contrôlée et étude préliminaire de leur auto-organisation / Amphiphilic and thermosensitive block copolymers : controlled synthesis and preliminary study of their self organization

Qayouh, Hicham 17 December 2013 (has links)
Les travaux présentés dans ce manuscrit ont porté sur l'élaboration de nouveaux copolymères dibloc amphiphiles (poly(ε-caprolactone)-b-poly(méthacrylate d'oligo(éthylène glycol) méthyl éther) biodégradables, thermostimulables et susceptibles d'être employés dans des applications respectueuses de l'environnement comme le traitement des eaux contaminées. La particularité de ces copolymères provient d'une part de la différence de solubilité des deux blocs et d'autre part de l'association d'un bloc hydrophobe biodégradable à un bloc thermostimulable hydrophile. Les propriétés de ces copolymères en milieu aqueux ont ainsi été évaluées en fonction de la température. Ces composés ont été obtenus par la combinaison de deux techniques de polymérisation contrôlée en utilisant un amorceur difonctionnel. Pour cela, deux stratégies ont été testées : i) la polymérisation par ouverture de cycle (POC) de l'ε-caprolactone à partir d'un macro-amorceur de poly(méthacrylate d'oligo(éthylène glycol) méthyl éther) à terminaison OH après avoir mis au point les conditions expérimentales de la POC en comparant plusieurs catalyseurs. ii) par polymérisation radicalaire par transfert d'atome (ATRP) du méthacrylate d'oligo(éthylène glycol) amorcée à partir d'une poly(ε-caprolactone) à extrémité bromée. Les températures critiques inférieures de solubilité (LCST) de ces copolymères ont été déterminées par UV visible. Leurs comportements micellaires ont été étudiés par mesures HPPS / The development of new biodegradable diblock copolymers poly(ε-caprolactone)-b-poly[oligo(ethylene glycol)methyl ether methacrylate], which could be used in environmental friendly applications such as treatment of contaminated water has been the main goal of this work. For the preparation these copolymers, the ring-opening polymerization (ROP) and the Atom Transfer Radical Polymerization (ATRP) were combined by using a bifunctional initiator. The two-step route for the synthesis of these copolymers was using either ATRP or ROP as first step and the other polymerization secondly. Each polymerization was studied carefully in order to control the macromolecular parameters of the copolymers. On the one hand, the ATRP of methacrylates bearing oligo(ethylene glycol) was carried out by using poly(ε-caprolactone) with bromide end-group as macroinitiator. On the other hand, the ring opening polymerization of ε-caprolactone was initiated by the hydroxyl end-group of the poly[oligo(ethylene glycol)methyl ether methacrylate], using tin octoate, tin tetrakis(phenylethynyl) or bismuth triflate as catalysts. The Low Critical Solution Temperature (LCST) of these amphiphilic diblock copolymers in aqueous medium have been determined by UV-visible spectroscopy. Their micellar behaviors were also studied by measuring size by HPPS
449

Relationship between stunting in children 6 to 36 months of age and maternal employment status in Peru: A sub-analysis of the Peruvian Demographic and Health Survey

Chávez-Zárate, Airin, Maguiña, Jorge L., Quichiz-Lara, Antoinette Danciana, Zapata-Fajardo, Patricia Edith, Mayta-Tristan, Percy 04 1900 (has links)
Objectives This study aimed to determine the relationship between stunting in children 6 to 36 months old and maternal employment status in Peru. Methods A secondary data analysis was conducted using information from the Demographic and Health Survey (DHS) in Peru. We used a representative sample of 4637 mother-child binomials to determine the association between stunting in children 6 to 36 months of age and the employment status of their mothers. Results The prevalence of stunting among children was 15.9% (95% CI: 13.9–16.7). The prevalence of working mothers was 63.7%. No association was found between maternal employment status and the presence of stunting in children [prevalence ratio (PR) = 1.04; 95% confidence interval (95% CI): 0.9 to 1.2; p = 0.627). However, on multivariate analysis we found that the prevalence of stunting was significantly higher among children of mothers performing unpaid work (12.4%) (PR = 1.38; 95% CI: 1.2–1.6; p < 0.001) compared with those of paid working mothers. Conclusion No significant association was found between maternal employment status and the presence of stunting in children 6 to 36 months of age. However, children of mothers doing unpaid work are at higher risk of stunting. These findings support the implementation of educational programs and labour policies to reduce the prevalence of stunting among children. © 2019 Chávez-Zárate et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. / Revisión por pares / Revisión por pares
450

Mechanisms for modifying the physiochemical and physiomechanical properties of poly (lactic-co-glycoic) acid: the impact on controllled drug delivery

Sibambo, Sibongile Ruth 29 July 2011 (has links)
MPharm. Faculty of Health Sciences, University of the Witwatersrand, 2007

Page generated in 0.0669 seconds