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  • 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.
1

Turismo e imaginário : o percurso histórico do chocolate em Gramado/RS

Vargas, Daniela Pereira de 08 August 2013 (has links)
O chocolate é um alimento largamente consumido em muitos países, tanto em climas quentes como frios, na forma líquida ou sólida. A sua história remonta aos povos pré-colombianos, mas, em 1527, as sementes de cacau foram levadas para a Europa. No século XIX há a criação de equipamentos para melhorar o aspecto visual e o sabor do chocolate e a abertura, na Europa, das primeiras indústrias produtoras de chocolate. No Brasil, as primeiras fábricas foram inauguradas no final do século XIX e início do século XX, por imigrantes europeus. No Sul do Brasil, a presença do chocolate de forma comercial marcante se dá na cidade de Gramado (RS), a partir de 1975, com a inauguração, no local, da primeira fábrica de chocolate caseiro. Hoje, o produto é uma das representações do município e está consolidado no imaginário das pessoas, o que se reflete na sua associação com o turismo na região. Logo, o estudo se caracteriza por seu corte qualitativo e por seu caráter exploratório, tendo por objetivo geral reconstruir o histórico da presença do chocolate em Gramado (RS) entre os anos 1975 a 2012, como produto e imaginário, na sua associação local com o turismo. Como objetivos específicos, a dissertação propôs contextualizar historicamente a presença do chocolate em Gramado (RS) e contextualizar teoricamente os imaginários no seu vínculo com o turismo no local. Como metodologia, o estudo utilizou a história oral, com apoio das pesquisas bibliográfica e documental. A pesquisa identificou que o produto surgiu de uma proposta trazida da Argentina por Jayme Prawer. Com a introdução desse produto, Gramado passa a reproduzir o imaginário argentino associado ao produto, e em torno do chocolate, um imaginário de produto sofisticado, para um consumo de elite e de produção caseira. Com o decorrer dos anos passa a construir sobre o chocolate um imaginário europeu e a trabalhá-lo na forma artesanal. No momento que adota o conceito de tematização, passa-se à presença de um imaginário disneyficado. Hoje, as duas linhas de imaginário estão fortemente presentes no chocolate de Gramado e no município: o de europeização e o de disneyficação. A pesquisa também mostrou que os imaginários do chocolate alimentam o turismo local. / Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-06-26T17:54:14Z No. of bitstreams: 1 Dissertacao Daniela Pereira de Vargas.pdf: 2705564 bytes, checksum: 2e92a859281548c094d027d2a06c5b2b (MD5) / Made available in DSpace on 2014-06-26T17:54:14Z (GMT). No. of bitstreams: 1 Dissertacao Daniela Pereira de Vargas.pdf: 2705564 bytes, checksum: 2e92a859281548c094d027d2a06c5b2b (MD5) / The chocolate is a food wide consumed in many countries, as much in hot climates as cold, is consumed in liquid or solid form. Its history retraces to the pre-Columbian people, but, in 1527, the cacao seeds had been taken from Europe. In the nineteenth century they’ve created equipments to improve the visual aspect and the flavor of Chocolate and the same century they’ve opened the first factories of Chocolate in Europe. In Brazil, the first factories were opened in the late nineteenth and earlier twentieth century by European immigrants. In the south of Brazil, the presence of the chocolate is an outstanding commercial form is in Gramado (RS), from 1975, with the inauguration of the first homemade Chocolate factory. Today, the product is one of the representations of the city, the opinion before mentioned reflects in its association to the tourism in the Region. Therefore, the study is characterized by its qualitative exploratory character, having for general objective to reconstruct the description of the presence of the Chocolate in Gramado (RS) between 1975 and 2012, as an imaginary product and, in its local association to the tourism. As specific objective of the proposed dissertation contextualize historically the presence of Chocolate in Gramado / RS and theoretically contextualize the imaginary in its bond with the local tourism. As methodology, the study is made by oral history, with support of the bibliographical and documentary research. The research identified that the product appeared of a proposal brought from Argentina for Jayme Prawer. With the introduction of this product, Gramado starts to play Argentinian imagery associated with the product, and around an imaginary Chocolate Product sophisticated for elite consumption and home production. With elapsing of the years it starts to construct on the Chocolate an imaginary European and it works as homade form. At the moment that adopts the themig concept, it passes the presence of an imaginary of Disneyworld. Today, the two lines of imaginary are strong presence in the Chocolate of Gramado and the city: of Europeanization and of Disneyfication. The survey also showed that the imaginary of Chocolate feed the local tourism.
2

Análise do potencial turístico das lagoas costeiras de Osório, Rio Grande do Sul

Reichert, Leonardo 07 August 2015 (has links)
As lagoas costeiras localizadas no Rio Grande do Sul – RS, a exemplo de outros ambientes lacustres no mundo, podem vir a se tornar importantes atrativos turísticos. A área de estudo compreende o município de Osório – RS, que possui em seu território, um dos maiores complexos lagunares do Brasil, abrangendo 23 lagoas. Com objetivo de determinar o potencial turístico das lagoas de Osório, foram selecionadas seis lagoas: Lagoa dos Barros, Lagoa do Marcelino, Lagoa do Peixoto, Lagoa do Caconde, Lagoa da Pinguela e Lagoa do Horácio. Para avaliação da potencialidade turística destas lagoas foram analisados fatores internos e externos determinantes do desenvolvimento turístico. Entre os fatores externos, relacionados a Osório, observou-se acessibilidade ao município; infraestrutura turística; atrativos turísticos e eventos e promoção do turismo no município. Entre os fatores internos, relacionados às lagoas, foram analisados: acessibilidade; qualidade da água; serviços turísticos; infraestrutura pública de apoio ao turismo; preservação do recurso natural; sensibilização ambiental; processo de turistificação e importância da lagoa. O levantamento de dados foi realizado por meio de observação in loco, registro fotográfico e entrevistas com gestores municipais e usuários das lagoas. Os fatores internos, determinantes do potencial turístico relacionado às lagoas foram avaliados e quantificados de acordo com pontuação preestabelecida. Verifica-se que as lagoas costeiras de Osório têm potencial para o desenvolvimento turístico, no entanto, necessitam de um planejamento estratégico e melhorias específicas que vão desde a implementação de infraestrutura até a recuperação da qualidade da água. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-12-04T11:36:07Z No. of bitstreams: 1 Dissertacao Leonardo Reichert.pdf: 6392006 bytes, checksum: 64b229639bec1a1158b6c849c6e7d837 (MD5) / Made available in DSpace on 2015-12-04T11:36:07Z (GMT). No. of bitstreams: 1 Dissertacao Leonardo Reichert.pdf: 6392006 bytes, checksum: 64b229639bec1a1158b6c849c6e7d837 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES / The lakes located in Rio Grande do Sul – RS, like other lacustrine environments in the world, have the potential to become important tourist attractions. In the present study, the focused area comprises the city of Osório – RS, which counts with one of the largest lake complex in Brazil, covering 23 lakes. In order to determine the tourism potential of these lakes it was selected six ones, which are: Lagoa dos Barros, Lagoa do Marcelino, Lagoa do Peixoto, Lagoa do Caconde, Lagoa da Pinguela and Lagoa do Horácio. In order to evaluate the tourist potential of these lakes it was analyzed both internal and external determinant factors for tourist development. Among the external factors related to Osório, it was observed the accessibility to the municipality; tourist infrastructure; tourist attractions and events, and the promotion of tourism in the city. The following internal factors related to the lakes were analyzed: accessibility; water quality; tourist services; public infrastructure in support of tourism; preservation of natural resource; environmental awareness; touristification process and the importance of lakes. The data were collected through in loco observation and with interviews with municipal managers and users of the lakes. For the in loco observation, along with photographic record, we used an instrument containing the criteria for analysis of the selected factors. The determining internal factors of the tourist potential related to lakes have been assessed and quantified according to the preset score evaluation. The data showed that Osório’s costal lakes presented potential for tourism development. However, they require a strategic planning and specific improvements ranging from infrastructure implementation to the recovery of water quality.
3

Análise do potencial turístico das lagoas costeiras de Osório, Rio Grande do Sul

Reichert, Leonardo 07 August 2015 (has links)
As lagoas costeiras localizadas no Rio Grande do Sul – RS, a exemplo de outros ambientes lacustres no mundo, podem vir a se tornar importantes atrativos turísticos. A área de estudo compreende o município de Osório – RS, que possui em seu território, um dos maiores complexos lagunares do Brasil, abrangendo 23 lagoas. Com objetivo de determinar o potencial turístico das lagoas de Osório, foram selecionadas seis lagoas: Lagoa dos Barros, Lagoa do Marcelino, Lagoa do Peixoto, Lagoa do Caconde, Lagoa da Pinguela e Lagoa do Horácio. Para avaliação da potencialidade turística destas lagoas foram analisados fatores internos e externos determinantes do desenvolvimento turístico. Entre os fatores externos, relacionados a Osório, observou-se acessibilidade ao município; infraestrutura turística; atrativos turísticos e eventos e promoção do turismo no município. Entre os fatores internos, relacionados às lagoas, foram analisados: acessibilidade; qualidade da água; serviços turísticos; infraestrutura pública de apoio ao turismo; preservação do recurso natural; sensibilização ambiental; processo de turistificação e importância da lagoa. O levantamento de dados foi realizado por meio de observação in loco, registro fotográfico e entrevistas com gestores municipais e usuários das lagoas. Os fatores internos, determinantes do potencial turístico relacionado às lagoas foram avaliados e quantificados de acordo com pontuação preestabelecida. Verifica-se que as lagoas costeiras de Osório têm potencial para o desenvolvimento turístico, no entanto, necessitam de um planejamento estratégico e melhorias específicas que vão desde a implementação de infraestrutura até a recuperação da qualidade da água. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES / The lakes located in Rio Grande do Sul – RS, like other lacustrine environments in the world, have the potential to become important tourist attractions. In the present study, the focused area comprises the city of Osório – RS, which counts with one of the largest lake complex in Brazil, covering 23 lakes. In order to determine the tourism potential of these lakes it was selected six ones, which are: Lagoa dos Barros, Lagoa do Marcelino, Lagoa do Peixoto, Lagoa do Caconde, Lagoa da Pinguela and Lagoa do Horácio. In order to evaluate the tourist potential of these lakes it was analyzed both internal and external determinant factors for tourist development. Among the external factors related to Osório, it was observed the accessibility to the municipality; tourist infrastructure; tourist attractions and events, and the promotion of tourism in the city. The following internal factors related to the lakes were analyzed: accessibility; water quality; tourist services; public infrastructure in support of tourism; preservation of natural resource; environmental awareness; touristification process and the importance of lakes. The data were collected through in loco observation and with interviews with municipal managers and users of the lakes. For the in loco observation, along with photographic record, we used an instrument containing the criteria for analysis of the selected factors. The determining internal factors of the tourist potential related to lakes have been assessed and quantified according to the preset score evaluation. The data showed that Osório’s costal lakes presented potential for tourism development. However, they require a strategic planning and specific improvements ranging from infrastructure implementation to the recovery of water quality.
4

Turismo e imaginário : o percurso histórico do chocolate em Gramado/RS

Vargas, Daniela Pereira de 08 August 2013 (has links)
O chocolate é um alimento largamente consumido em muitos países, tanto em climas quentes como frios, na forma líquida ou sólida. A sua história remonta aos povos pré-colombianos, mas, em 1527, as sementes de cacau foram levadas para a Europa. No século XIX há a criação de equipamentos para melhorar o aspecto visual e o sabor do chocolate e a abertura, na Europa, das primeiras indústrias produtoras de chocolate. No Brasil, as primeiras fábricas foram inauguradas no final do século XIX e início do século XX, por imigrantes europeus. No Sul do Brasil, a presença do chocolate de forma comercial marcante se dá na cidade de Gramado (RS), a partir de 1975, com a inauguração, no local, da primeira fábrica de chocolate caseiro. Hoje, o produto é uma das representações do município e está consolidado no imaginário das pessoas, o que se reflete na sua associação com o turismo na região. Logo, o estudo se caracteriza por seu corte qualitativo e por seu caráter exploratório, tendo por objetivo geral reconstruir o histórico da presença do chocolate em Gramado (RS) entre os anos 1975 a 2012, como produto e imaginário, na sua associação local com o turismo. Como objetivos específicos, a dissertação propôs contextualizar historicamente a presença do chocolate em Gramado (RS) e contextualizar teoricamente os imaginários no seu vínculo com o turismo no local. Como metodologia, o estudo utilizou a história oral, com apoio das pesquisas bibliográfica e documental. A pesquisa identificou que o produto surgiu de uma proposta trazida da Argentina por Jayme Prawer. Com a introdução desse produto, Gramado passa a reproduzir o imaginário argentino associado ao produto, e em torno do chocolate, um imaginário de produto sofisticado, para um consumo de elite e de produção caseira. Com o decorrer dos anos passa a construir sobre o chocolate um imaginário europeu e a trabalhá-lo na forma artesanal. No momento que adota o conceito de tematização, passa-se à presença de um imaginário disneyficado. Hoje, as duas linhas de imaginário estão fortemente presentes no chocolate de Gramado e no município: o de europeização e o de disneyficação. A pesquisa também mostrou que os imaginários do chocolate alimentam o turismo local. / The chocolate is a food wide consumed in many countries, as much in hot climates as cold, is consumed in liquid or solid form. Its history retraces to the pre-Columbian people, but, in 1527, the cacao seeds had been taken from Europe. In the nineteenth century they’ve created equipments to improve the visual aspect and the flavor of Chocolate and the same century they’ve opened the first factories of Chocolate in Europe. In Brazil, the first factories were opened in the late nineteenth and earlier twentieth century by European immigrants. In the south of Brazil, the presence of the chocolate is an outstanding commercial form is in Gramado (RS), from 1975, with the inauguration of the first homemade Chocolate factory. Today, the product is one of the representations of the city, the opinion before mentioned reflects in its association to the tourism in the Region. Therefore, the study is characterized by its qualitative exploratory character, having for general objective to reconstruct the description of the presence of the Chocolate in Gramado (RS) between 1975 and 2012, as an imaginary product and, in its local association to the tourism. As specific objective of the proposed dissertation contextualize historically the presence of Chocolate in Gramado / RS and theoretically contextualize the imaginary in its bond with the local tourism. As methodology, the study is made by oral history, with support of the bibliographical and documentary research. The research identified that the product appeared of a proposal brought from Argentina for Jayme Prawer. With the introduction of this product, Gramado starts to play Argentinian imagery associated with the product, and around an imaginary Chocolate Product sophisticated for elite consumption and home production. With elapsing of the years it starts to construct on the Chocolate an imaginary European and it works as homade form. At the moment that adopts the themig concept, it passes the presence of an imaginary of Disneyworld. Today, the two lines of imaginary are strong presence in the Chocolate of Gramado and the city: of Europeanization and of Disneyfication. The survey also showed that the imaginary of Chocolate feed the local tourism.
5

The role of macrophages in respiratory syncytial virus infection of mice

Hayes, Peter John January 1993 (has links)
No description available.
6

Processing and formulation insights for designing quality into lyophilised biopharmaceuticals

Beech, Karen E. January 2015 (has links)
This thesis makes an original contribution to the field of formulation development by providing new experimental data and insights into the effect of processing and formulation conditions on the quality of lyophilised biopharmaceuticals. The quality attributes of lyophilised products include: a quick reconstitution time, product elegance and protein stability, which are known to be affected by processing and formulation parameters. However, choice of formulation excipients or processing conditions often relies on previous experience rather than mechanistic insight. The motivation of this thesis was therefore to provide a greater understanding of how process variables andexcipient choice affect these quality attributes. Bovine serum albumin (BSA) and immunoglobulin G (IgG) were used as model proteins to investigate formulation conditions, which included the excipient, the lyophilisation cooling profile and duration of the annealing step. BSA was also used as a model protein to explore the effects of sucrose and arginine as lyoprotectants. Unique to this study was the investigation of arginine salts as lyoprotectants, wherein the counterions were dicarboxylic acids with increasing chain length. Two key results regarding quality attributes were observed. Firstly, characterisation of the lyophilised structure established that there was an optimal annealing time, beyond which there was an increase in primary drying time, batch heterogeneity and variable moisture content. Secondly, a relationship was found between decreasing dicarboxylic acid chain length and improved protein stability. To explain these findings, two mechanisms are proposed that account for ice crystal growth during annealing and the observed changes in protein stability at the molecular level. Significantly, this research provides insights for future formulation development studies.
7

Thai stakeholder's perceptions of the introduction of the Doctor of Pharmacy programme

Chanakit, Teeraporn January 2016 (has links)
Global pharmacy education and pharmacy practice continue to face remarkable changes. Many countries are undergoing major transformations in the field of pharmacy education. In developing countries, there is an increasing trend towards adopting the PharmD degree. Thai pharmacy education has transitioned from having two entry-level degrees – a 5-year BPharm (with three main tracks: pharmaceutical care, pharmaceutical sciences, social and administrative pharmacy) and a traditional 6-year PharmD (pharmaceutical care) programme – to a single national 6-year PharmD programme or ‘an all-PharmD programme’ (including industry pharmacy and pharmaceutical care tracks). Similar to other countries that have also been transitioning to ‘an all-PharmD programme’, there was limited evidence for the merit of the transition in Thailand. Although opinions and questions put forth on social media networks triggered debates about the need for the transition, there is a lack of an evidence-based and in-depth investigation about the reasons for this transition. This thesis explores the experiences and perceptions held by stakeholders concerning the transition towards an all-PharmD programme in Thailand. The study used a mixed methods approach through a quantitative analysis of surveys (Phase 1 and Phase 2) and interviews with stakeholders who were involved in pharmacy education (Phase 3). Findings from the three phases and other resources were triangulated and validated (by comparing and confirming them) to provide a better picture of the transition of pharmacy education in Thailand. Phase 1: A survey of the status of Thai pharmacy education. This study aimed to explore the status of pharmacy education in Thailand by using a questionnaire survey. The surveys were distributed to the deans of all 19 faculties of pharmacy in Thailand. The response rate was 84% (n = 16). Characteristics of the Faculties of Pharmacy, the teaching staff, types of PharmD programme, the number of training sites and quality assurance mechanisms were reported. The results showed that the Thai PharmD curriculum includes industrial pharmacy and clinical pharmacy tracks that differentiate it from the traditional US PharmD programme, which only focuses on patient care. There was a shortage of academic staff in the pharmaceutical care area and some faculties needed to better prepare for their training sites. Phase 2: A survey of the pharmacists’ perceptions towards the suitability of the PharmD graduates employed in hospital and community pharmacy settings and the competencies difference between the BPharm and the PharmD graduates. This study aimed to explore Thai pharmacists’ perceptions regarding the suitability of the PharmD graduates employed in hospital and community pharmacy settings, as well as the competency differences between the BPharm and PharmD graduates. A cross-sectional survey questionnaire was distributed to 180 hospital pharmacists and 200 community pharmacists during two conferences. The response rate was 55.6% among hospital pharmacists and 20% in the community pharmacists group. The findings highlighted that the PharmD graduates were suited for large hospital settings as they were well coordinated with the health care team. However, there were concerns regarding the suitability of the PharmD graduates for primary care settings, because of their lack of training in health promotion. Half of the respondents perceived PharmD graduates as having higher competencies in clinical activities and being more prepared to work than BPharm graduates. However, the other half of the respondents perceived the competencies of both pharmacy qualifications as being similar; PharmD graduates provide non-clinical activities similar to BPharm graduates, due to numerous barriers (e.g., high workload in dispensing services and the shortage of pharmacists) preventing PharmD pharmacists from providing direct pharmaceutical care services. Phase 3: Thai stakeholder’s perceptions of the introduction of the PharmD programme: a qualitative study. This qualitative study aimed to understand the experiences and perceptions of stakeholders, regarding the transition to an all-PharmD programme in Thailand. Semi-structured interviews were conducted with 130 stakeholders (e.g., policy makers, educators, health care providers, patients, students, and parents). The data were audio recorded, transcribed verbatim and analysed using an inductive thematic analysis. Three main themes were derived from the findings: 1) influences on the transition (e.g., the US-Thai consortium for the development of pharmacy education); 2) perceived benefits (e.g., improved pharmacy competencies from generalist to specialists); and 3) concerns (e.g., the higher cost of a longer period of study, and insufficient preceptors and training sites). This PhD study carries important implications for both universities and policy makers. Faculties of pharmacy should consider a long-term plan to develop sufficient qualified academic staff and preceptors. Policy makers should prepare a strategic plan for the future workforce supply and requirements, increase the flexibility of the PharmD curriculum during its transition stage, and prepare a supportive and enabling system for PharmD graduates to provide advanced practice at their full potential. Close coordination between faculties, the Pharmacy Council of Thailand and pharmacy professional organisations is needed to ensure that pharmacy education provides the necessary competencies for graduates to offer a high level of needed pharmacy services. Further research focussing on the outcome, impact and efficiency of the PharmD programme is also needed. To conclude, in this thesis, the issues surrounding the transition to an all-PharmD programme in Thailand were carefully investigated. This study reflects the influences and the requirements of the transition that it was initiated, in order to meet the need for higher levels of competency for the nation’s pharmacists and is influenced by many factors. The stakeholders perceived benefits from the transition. They thought that the PharmD graduates will have higher competencies and be ready to work as pharmacists compared to graduates from the previous pharmacy curriculum. The findings also addressed the following issues concerning curriculum change: the higher costs of a longer period of study, the mismatch between the pharmacy graduates’ competency and the job market’s needs and the shortage of qualified preceptors.
8

Semi-synthesis of novel cardamonin analogues and identification of a highly active Cu(II)-cardamonin complex that inhibits migration and induces apoptosis via inhibition of mTOR expression

Bin Break, Mohammed Khaled Ali January 2018 (has links)
Lung cancer is considered a major health concern and is responsible for most cancer-related deaths. Nasopharyngeal carcinoma (NPC) is another type of cancer that is predominantly in China and has a low survival rate, which makes it a serious health issue. There is currently no cure for lung cancer and NPC, so it was decided to investigate derivatives of the highly bioactive natural product, cardamonin, for a potential drug candidate. 19 analogues of cardamonin were synthesised and tested against A549 (lung) and HK1 (NPC) cell lines. The techniques employed in synthesising the analogues were one-step reactions which included alkylation, acylation, reduction, condensation, cyclisation and complexation reactions. The analogues were fully characterised. MTS assay showed that several derivatives, such as the allyl derivative of cardamonin (2) and cardamonin’s Cu (II) complex (19), had more potent cytotoxic activities than cardamonin. Furthermore, the active analogues have generally demonstrated lower toxicity towards normal MRC5 cells. Structure-activity relationship (SAR) analysis showed the importance of the ketone and alkene groups for bioactivity, while substituting cardamonin’s phenolic groups with more polar moieties resulted in activity enhancement. As part of the SAR study and further exploration of chemical space, the effect of metal coordination on cytotoxicity was also investigated, but it was only possible to successfully obtain the Cu (II) complex of cardamonin (19), and the metal ion enhanced bioactivity. 19 was the most potent analogue possessing IC50 values of 13.2 μM and 0.7 μM against A549 and HK1 cells, corresponding to a 5- and 32-fold increase in activity, respectively. It was also able to inhibit the migration of A549 and HK1 cells. Mode of action studies revealed that 19 induced DNA damage in both cell lines resulting in G2/M-phase arrest, which further led to apoptosis via the activation of caspase-9 and caspase-3/7. Moreover, qPCR analysis showed that 19 inhibited the expression of the mammalian target of rapamycin (mTOR) by >50% in A549 and HK1 cells which indicated that it exerted its anticancer activity, at least in part, via inhibition of the mTOR signalling pathway. So molecular docking of cardamonin and 19 to mTOR was performed and the study showed that the higher activity of 19 might be due to formation of further hydrogen bond interactions with the receptor resulting in a higher binding free energy of -9.8 kcal/mol. Therefore, all these assays have further proven the high bioactivity of 19. However, further in vivo and animal model studies would have to be conducted in order to confirm the potential of 19 as an anticancer agent.
9

In-vitro characterisation of targeting ligands for enhanced delivery across the blood-brain barrier

Sim, Jack January 2018 (has links)
The blood-brain barrier (BBB) is the most extensive and restrictive barrier to brain delivery for therapeutic agents. A low proportion of low molecular-weight agents can cross into the CNS. This decreases further as the molecular weight increases, meaning therapeutic antibodies, oligonucleotides and other supramolecular entities effectively cannot reach therapeutic levels within the CNS. Targeting ligands against receptors thought to undergo transcytosis across the brain microvascular endothelial cells (BMECs), can boost CNS delivery of therapeutics. Understanding these mechanisms, in an in-vitro setting, has proved challenging, due to the constraints of cell culture systems and the difficulty to replicate the in-vivo environment. With even the most extensively studied targeting receptor, transferrin receptor, not producing clear evidence to suggest the occurrence of transcytosis. To understand in-vitro trafficking of brain targeting ligands a pulse-chase assay, in combination with sub-cellular localisation microscopy was developed and compared to the current permeability-based assay method. The characterisation was done by comparison of transferrin receptor ligands; native holo-transferrin, the 8D3 antibody and a low-affinity variant; with the non-specific uptake probe, dextran. The method could distinguish between the two endocytosis methods, with concentration-dependent efflux efficiency observed with the targeted probes. The combination of techniques was then applied to the novel targeting ligand, Rabies-Virus Glycoprotein (RVG) peptide, to assess its suitability as a brain delivery. Studies were performed to confirm the target receptor of the RVG peptide, including competitive uptake, siRNA knockdown methods. The RVG peptide demonstrated desirable delivery characteristics, and the target receptor was confirmed as the α7 nicotinic acetylcholine receptor. Finally, attempts were made to develop a total internal reflection fluorescence (TIRF) microscopy assay for the assessment of ligand arrival at the basolateral membrane of BMECs. Initial work for this was performed with the transferrin receptor and transferrin, using both labelled ligand and photoswitchable receptor constructs. In summary, the pulse-chase assay provides a complementary technique to permeability assays for the assessment of brain targeting ligand trafficking in BMEC cell-lines in-vitro.
10

Amino acid-modified ultrafine superparamagnetic iron oxide nanoparticles : fabrication, size characterisation and potential cytotoxicity and cell interaction

Alali, Muqdam January 2018 (has links)
The potential applications of transition metals-based nanoparticles are expanding in the biomedical field. Oxides of iron are the matter of investigation in this study where various preparations of ultrafine superparamagnetic iron oxide nanoparticles (USPIONs) were fabricated using flow injection technology with spinning disc reactor. Basically, two types of preparation parameters were examined; first, instrument-related (physical) parameters and, second, chemistry-related parameters. USPIONs fabricated by this instrument showed fine-tuning size adjustment. Subsequent surface modification of these nanoparticles produced hydrophobic, hydrophilic and neutral amino acids modified surface, whereby aminoacid ‘monomers’, rather than polymeric materials were used. Transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential measurements, thermogravimetric analysis (TGA) and fourier-transform infrared-attenuated total reflection spectroscopy (FTIR-ATR) were employed to characterise the coated nanoparticles. The data show that ultrafine, 4-9 nm sized coated nanoparticles show good dispersion upon TEM imaging. Measurement of number of monomers molecules effectively associated with USPIONs suggest formation of multilayer of amino acid adsorbed on nanoparticles (NPs). Prediction of NPs- amino acid association mechanism by FTIR-ATR study reveals presence of either monodentate or bidentate molecular adsorption on the surface of USPIONs. In the second stage of the project, interactions of differently modified USPIONs with epithelial cell layer (model of intestinal epithelium) are now investigated. An intestinal adenocarcinoma cell line (Caco-2) is used for performing the in vitro studies. The toxicity of three types of USPIONs (Asp-, His-, and Phe-USPIONs) reveals that these particles have potential toxic effect on biological system. Relatively long term exposure to these particles (24 hours) with high concentration 250 μg/ml and more was found to enhance apoptotic mode of cell death. Cell-NPs interaction study displayed presence of different forms of cellular interaction which are supposed to be related to USPIONs surface chemistry. While some of Phe-USPIONs are found internalised and accumulated inside some cells, Asp-USPIONs exhibit different interaction mode where the cell membrane of most cells is covered with thin layer of NPs without significant cell penetration. This gives an indication that metal oxide NPs (USPIONs) that are associated by their surface with small molecules could render these NPs with aggravated toxicity and cell-NPs interaction and hence long term effect.

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