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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.
41

An Investigation of Factors Affecting Test Equating in Latent Trait Theory

Suanthong, Surintorn 08 1900 (has links)
The study investigated five factors which can affect the equating of scores from two tests onto a common score scale. The five factors studied were: (a) distribution type (i.e., normal versus uniform); (b) standard deviation of itemdifficulties (i.e., .68, .95, .99); (c) test length or number of test items (i.e., 50,100, 200); (d) number of common items (i.e., 10,20,30); and (e) sample size (i.e., 100, 300, 500). The significant two-way interaction effects were for common item length and test length, standard deviation of item difficulties and distribution type, and standard deviation of item difficulties and sample size.
42

Caracterização físico-química e fotodinâmica de fotossensibilizadores: efeito da modificação química para aumentar a solubilidade em meio aquoso / Physical-Chemistry and photodynamic characterization of photosensitizers: effect of chemical modification to increase the solubility in aqueous medium

Gonçalves, Joyce Laura da Silva 29 April 2015 (has links)
A hidrofobicidade e a estrutura planar do orbital π estendido de fotossensibilizadores do tipo clorina e hipericina podem favorecer a agregação destes compostos em meio aquoso. Esta agregação pode reduzir a eficiência fotodinâmica e a aplicabilidade destes compostos em diagnósticos e na Terapia fotodinâmica. Uma estratégia para minimizar esta limitação é a modificação destas moléculas pela inserção de grupos hidrofílicos. Neste trabalho foram utilizadas técnicas espectroscópicas para caracterizar as propriedades físico-químicas e fotodinâmicas de derivados de clorina (CHL), e hipericina (HY) obtidos por meio de inserções dos grupos hidrofílicos trizma e glucamina, respectivamente: Clorina-Trizma (CHL-T) e Hipericina Glucamina (HY-G). Os resultados mostraram que estas modificações estruturais aumentaram em até 20% a solubilidade destes compostos em meio aquoso. No entanto, devido à solubilidade parcial dos fotossensibilizadores na ausência de cargas elétricas foram identificados agregados do tipo H em meio ácido, neutro e na presença de íons em solução aquosa. Tais agregados foram solubilizados em meio alcalino e por microambientes micelares dos surfactantes CTAB, SDS e Tween 20. Os agregados do tipo H acarretaram ainda na redução da constante de velocidade de fotobranqueamento e da formação de oxigênio singleto dos fotossensibilizadores em meio aquoso. Contudo, as clorinas foram cerca de 15 vezes mais eficientes do que a hipericinas na geração deste radical citotóxico. A análise sistemática do potencial fotodinâmico dos fotossensibilizadores em células VERO e HUVEC (não tumorais) e HEp-2 (tumoral) foi realizada por meio de um planejamento fatorial combinando-se a concentração, tempo de acumulação do fotossensibilizador no interior da célula e a dose de luz. Esta análise mostrou que o tempo de acumulação do fotossensibilizador é um parâmetro significante para se erradicar seletivamente as células cancerígenas. Ao contrário das células não tumorais, nas células HEp-2 a quantidade de fotossensibilizador acumulado foi proporcional à lipoficilidade dos fotossensibilizadores. A análise quimiométrica resultou ainda em um modelo matemático para a estimativa dos valores da concentração inibitória média que foi validada por meio de comparação estatística com os valores experimentais determinados para os fotossensibilizadores. As hipericinas foram mais fototóxicas para as células tumorais do que as clorinas. Nas células não tumorais os derivados foram menos citotóxicos, sugerindo o uso destes compostos para a inativação seletiva de células tumorais. Todas essas características permitem que os compostos sejam empregados como fotossensibilizadores em diagnósticos e tratamentos fotodinâmicos. / The hydrophobicity and planar structure of π extended orbital of photosensitizers like chlorine and hypericin may favor the aggregation of these compounds in aqueous medium. This aggregation can reduce their photodynamic efficiency and applicability in Photodynamic Therapy and diagnosis. A strategy to minimize this limitation is the modification of these molecules by the inclusion of hydrophilic groups. In this study spectroscopic techniques were used to characterize the physical-chemistry and photodynamic properties of chlorin (CHL) and hypericin (HY) derivatives obtained by insertion of trizma glucamine and hydrophilic groups, respectively: Trizma-Chlorin (CHL-T) and glucamine Hypericin (HY-G). The results showed that these structural modifications increased by 20% the solubility of these compounds in an aqueous medium. However, due to partial solubility of the photosensitizers in electric charges absence, H-aggregates were found in acid, neutral and ions presence in aqueous solution. These aggregates were solubilized by alkaline medium and micelar microenvironments of CTAB, SDS and Tween 20. H-aggregates were also responsible for the minor photobleaching rate constant and singlet oxygen formation by photosensitizers in an aqueous medium. Although, chlorins were about 15 times more efficient than hypericins on the singlet oxygen generation. The systematic analysis of photosensitizers photodynamic potential in Vero and HUVEC (non-tumor cells) and HEp-2 (tumor cells) was done using a factorial design combining the concentration of the photosensitizer, accumulation time of it into the cell and light doses. This analysis showed that the photosensitizer accumulation time is a significant parameter to eradicate selectively tumor cells. In contrast to non-tumor cells, in HEp-2 cells the accumulation rate was proportional of the lipophylicity of photosensitizer. The chemometric analysis resulted also in a mathematical model to estimate the half inhibitory concentration values. It had been statistical validated by comparing the experimental values determined for the photosensitizers. The hypericins have been more phototoxic to tumor cells than chlorines. In non-tumor cells derivatives were more cytotoxic than original compounds suggesting the use of these compounds for the selective inactivation of tumor cells. All these characteristics allow the use of these compounds as photosensitizers in photodynamic diagnostics and treatments.
43

Caracterização físico-química e fotodinâmica de fotossensibilizadores: efeito da modificação química para aumentar a solubilidade em meio aquoso / Physical-Chemistry and photodynamic characterization of photosensitizers: effect of chemical modification to increase the solubility in aqueous medium

Joyce Laura da Silva Gonçalves 29 April 2015 (has links)
A hidrofobicidade e a estrutura planar do orbital π estendido de fotossensibilizadores do tipo clorina e hipericina podem favorecer a agregação destes compostos em meio aquoso. Esta agregação pode reduzir a eficiência fotodinâmica e a aplicabilidade destes compostos em diagnósticos e na Terapia fotodinâmica. Uma estratégia para minimizar esta limitação é a modificação destas moléculas pela inserção de grupos hidrofílicos. Neste trabalho foram utilizadas técnicas espectroscópicas para caracterizar as propriedades físico-químicas e fotodinâmicas de derivados de clorina (CHL), e hipericina (HY) obtidos por meio de inserções dos grupos hidrofílicos trizma e glucamina, respectivamente: Clorina-Trizma (CHL-T) e Hipericina Glucamina (HY-G). Os resultados mostraram que estas modificações estruturais aumentaram em até 20% a solubilidade destes compostos em meio aquoso. No entanto, devido à solubilidade parcial dos fotossensibilizadores na ausência de cargas elétricas foram identificados agregados do tipo H em meio ácido, neutro e na presença de íons em solução aquosa. Tais agregados foram solubilizados em meio alcalino e por microambientes micelares dos surfactantes CTAB, SDS e Tween 20. Os agregados do tipo H acarretaram ainda na redução da constante de velocidade de fotobranqueamento e da formação de oxigênio singleto dos fotossensibilizadores em meio aquoso. Contudo, as clorinas foram cerca de 15 vezes mais eficientes do que a hipericinas na geração deste radical citotóxico. A análise sistemática do potencial fotodinâmico dos fotossensibilizadores em células VERO e HUVEC (não tumorais) e HEp-2 (tumoral) foi realizada por meio de um planejamento fatorial combinando-se a concentração, tempo de acumulação do fotossensibilizador no interior da célula e a dose de luz. Esta análise mostrou que o tempo de acumulação do fotossensibilizador é um parâmetro significante para se erradicar seletivamente as células cancerígenas. Ao contrário das células não tumorais, nas células HEp-2 a quantidade de fotossensibilizador acumulado foi proporcional à lipoficilidade dos fotossensibilizadores. A análise quimiométrica resultou ainda em um modelo matemático para a estimativa dos valores da concentração inibitória média que foi validada por meio de comparação estatística com os valores experimentais determinados para os fotossensibilizadores. As hipericinas foram mais fototóxicas para as células tumorais do que as clorinas. Nas células não tumorais os derivados foram menos citotóxicos, sugerindo o uso destes compostos para a inativação seletiva de células tumorais. Todas essas características permitem que os compostos sejam empregados como fotossensibilizadores em diagnósticos e tratamentos fotodinâmicos. / The hydrophobicity and planar structure of π extended orbital of photosensitizers like chlorine and hypericin may favor the aggregation of these compounds in aqueous medium. This aggregation can reduce their photodynamic efficiency and applicability in Photodynamic Therapy and diagnosis. A strategy to minimize this limitation is the modification of these molecules by the inclusion of hydrophilic groups. In this study spectroscopic techniques were used to characterize the physical-chemistry and photodynamic properties of chlorin (CHL) and hypericin (HY) derivatives obtained by insertion of trizma glucamine and hydrophilic groups, respectively: Trizma-Chlorin (CHL-T) and glucamine Hypericin (HY-G). The results showed that these structural modifications increased by 20% the solubility of these compounds in an aqueous medium. However, due to partial solubility of the photosensitizers in electric charges absence, H-aggregates were found in acid, neutral and ions presence in aqueous solution. These aggregates were solubilized by alkaline medium and micelar microenvironments of CTAB, SDS and Tween 20. H-aggregates were also responsible for the minor photobleaching rate constant and singlet oxygen formation by photosensitizers in an aqueous medium. Although, chlorins were about 15 times more efficient than hypericins on the singlet oxygen generation. The systematic analysis of photosensitizers photodynamic potential in Vero and HUVEC (non-tumor cells) and HEp-2 (tumor cells) was done using a factorial design combining the concentration of the photosensitizer, accumulation time of it into the cell and light doses. This analysis showed that the photosensitizer accumulation time is a significant parameter to eradicate selectively tumor cells. In contrast to non-tumor cells, in HEp-2 cells the accumulation rate was proportional of the lipophylicity of photosensitizer. The chemometric analysis resulted also in a mathematical model to estimate the half inhibitory concentration values. It had been statistical validated by comparing the experimental values determined for the photosensitizers. The hypericins have been more phototoxic to tumor cells than chlorines. In non-tumor cells derivatives were more cytotoxic than original compounds suggesting the use of these compounds for the selective inactivation of tumor cells. All these characteristics allow the use of these compounds as photosensitizers in photodynamic diagnostics and treatments.
44

Combinatorial properties of uniform designs and their applications in the constructions of low-discrepancy designs

Tang, Yu 01 January 2005 (has links)
No description available.
45

Desenvolvimento e otimização de péletes de liberação bifásica mediante delineamento experimental

Martins, Sarah Moherdaui 24 November 2015 (has links)
Made available in DSpace on 2017-07-10T13:59:25Z (GMT). No. of bitstreams: 1 DEFESA_SARAH_M_MARTINS.pdf: 1948811 bytes, checksum: b506b11e5b86370135e564286deabd70 (MD5) Previous issue date: 2015-11-24 / In recent years, the interest of the pharmaceutical industry for new drugs delivery system has been growing, especially aiming the optimization of therapy and reduction of side effects caused by conventional treatments. The multiparticulate systems, besides their techonological and biopharmaceutical advantages when compared to the monolithic systems, allow obtaining different ways of drug delivery, such as the biphasic system, capable of delivering the drug in separate fractions into the bloodstream, and ideal for the treatment of circadian diseases. Thus, this study aimed to obtain a multi particulate system biphasic release, lasting 24 hours, using a combination of polymeric materials hydroxypropyl methylcellulose and ethyl cellulose, as well as a full factorial design 2² to optimize the development stage. Furthermore, it was developed and validated analytical method by UV spectroscopy able to quantify the model drug used, propranolol hydrochloride (PROP) test and the content of dissolution of the dosage form. Using the sugar spheres coating technology, it was possible to obtain the proposed system with a reduced number of experiments. Pellets produced and used in the biphasic formulations showed mechanical characteristics within the expected quality parameters, showing that the technique is robust and can be applied on an industrial scale. The analytical method for the quantification of the proposed drug was linear, precise, accurate, robust against variations in wavelength of mark and sonication solvent in a concentration range of 0.80 - 96 mg L-1 and stable the experimental conditions analyzed, showing a method capable of generating highly reliable results and therefore able to be used in the laboratory routine quality control. / Nos últimos anos, o interesse da indústria farmacêutica por novos sistemas de liberação de fármacos vem crescendo, visando sobretudo a otimização da terapêutica e a diminuição dos efeitos colaterais ocasionados pelos tratamentos convencionais. Os sistemas multiparticulados, além de possuírem vantagens tecnológicas e biofarmacêuticas quando comparadas aos sistemas monolíticos, possibilitam a obtenção de diferentes padrões de liberação de drogas, como por exemplo, o sistema bifásico, capaz de disponibilizar o fármaco em frações distintas para a corrente sanguínea, sendo ideais para o tratamento das doenças circadianas. Desta maneira, o presente trabalho teve como objetivo a obtenção de um sistema multiparticulado de liberação bifásica, com duração de 24 horas, utilizando a combinação dos materiais poliméricos hidroxipropilmetilcelulose e etilcelulose, bem como um planejamento fatorial completo 2² para a otimização da etapa de desenvolvimento. Além disso, foi desenvolvido e validado um método analítico por espectroscopia de UV capaz de quantificar o fármaco modelo utilizado, cloridrato de propranolol (PROP), nos ensaios de teor e dissolução desta forma farmacêutica. Utilizando-se a tecnologia de revestimento de núcleos inertes de sacarose, foi possível a obtenção do sistema proposto com um número reduzido de experimentos. Os péletes produzidos e utilizados nas formulações bifásicas apresentaram características mecânicas dentro dos parâmetros de qualidade esperados, demostrando que a técnica é robusta e pode ser aplicada em escala industrial. O método analítico proposto para a quantificação do fármaco, mostrou-se linear, preciso, exato, robusto em relação a variações no comprimento de onda, marca de solvente e sonicação na faixa de concentração de 0,80 96 μg mL-1 e estável nas condições experimentais analisadas, evidenciando um método capaz de gerar resultados de alta confiabilidade e portanto apto a ser utilizado na rotina laboratorial de controle de qualidade.
46

Estrategias para mejorar la cobertura y difusión de los programas de educación sexual pre matrimonial de adolescentes de 15-18 años de la provincia de Lima, 2007

Arana López, Sara Adelina January 2009 (has links)
En el presente trabajo se han revisado Investigaciones existentes a nivel nacional e internacional sobre educación sexual. El estudio tiene como objetivo determinar las estrategias para mejorar la cobertura y difusión de los programas de educación sexual pre matrimonial de adolescentes de 15 – 18 años de la provincia de Lima. Para la obtención de los datos se aplico una encuesta, el análisis de los datos se realizo mediante el método multivariado, haciendo uso del análisis factorial Con el método se ha seleccionado las variables de mayor puntuación en cada grupo; también se uso las técnicas del planeamiento Estratégico. El análisis ha permitido determinar que los adolescentes no conocen sobre la difusión de los programas de educación sexual, y que la orientación lo reciben en las asignaturas de ciencias naturales o de psicología. Se concluye que la cobertura y difusión de los programas no llega a las instituciones educativas en un 90%, se determina que una de las estrategias es la participación masiva de padres de familia, maestros, profesionales de diferentes especialidades y alumnos universitarios de los últimos años de especialidad. / -- In this research work we have reviewed existing national and international sex education. The study aims to identify strategies to improve the coverage and dissemination of programs for pre-marriage sex education of adolescents 15 to 18 years in the province of Lima. To obtain the data was applied to a survey, data analysis was performed by the multivariate method, using the factorial analysis method was selected variables highest score in each group also use planning techniques Strategic. The analysis has identified that adolescents do not know about the spread of sex education programs, and that the guidance they receive in mathematics and natural sciences or psychology. We conclude that the coverage and dissemination of programs fails to educational institutions by 90%, it is determined that one of the strategies is the massive participation of parents, teachers, professionals of different specialties and college students in recent years specialty. / Tesis
47

Community pharmacist medication monitoring attitudes and decision making

Witry, Matthew John 01 December 2013 (has links)
Medication related problems occur frequently and can be difficult to predict. Medication monitoring by health care providers allows for problems to be identified before they become severe. Medication monitoring is an an emerging role for community pharmacists. This mixed methods study examines pharmacist perspectives on medication monitoring. Study methods included 12 semi-structured interviews, a mixed methods item generation process to create a pharmacist medication motioning attitude measure, and mailed factorial survey designed to assess pharmacist decision making related to asking non-adherence, side effect, and effectiveness questions for randomly generated refill dispensing vignettes. Hierarchical linear modeling was used to identify significant vignette level and pharmacist level variables associated with likelihood to ask the three monitoring questions. The qualitative analysis showed barriers to medication monitoring including time limitations, busyness, low patient expectation, and a perceived routine nature of refills by both patients and pharmacists. Monitoring non-adherence was a challenge because workflows often do not make non-adherence apparent to the pharmacists when the patient presents to the pharmacy. Lastly, monitoring interactions often are precipitated by "gateway conversations" which begin as technical or cost issues related to the prescription but then progress to monitoring issues when the patient reflects interest. Analysis of the survey showed in general, pharmacists had positive medication monitoring attitudes and worked in pharmacies somewhat conducive to medication monitoring, although there was variation. The factorial survey showed pharmacist monitoring attitudes were significantly associated with the likelihood to ask all three monitoring question types. For the different prescriptions involved, warfarin and hydrocodone were significantly associated with asking monitoring questions whereas fluoxetine and metoprolol appeared less question-worthy. The number of days late was associated with greater question asking likelihood suggesting days late is an important activator for pharmacist medication monitoring. Number of patients waiting was a barrier. This study shows community pharmacists are oriented to monitoring, but there are significant barriers which need to be addressed when advancing this role.
48

Factorial linear model analysis

Brien, Christopher J. January 1992 (has links) (PDF)
"February 1992" Bibliography: leaf 323-344. Develops a general strategy for factorial linear model analysis for experimental and observational studies, an iterative, four-stage, model comparison procedure. The approach is applicable to studies characterized as being structure-balanced, multitiered and based on Tjur structures unless the structure involves variation factors when it must be a regular Tjur structure. It covers a wide range of experiments including multiple-error, change-over, two-phase, superimposed and unbalanced experiments.
49

Design/Evaluation of A Methodology For Performance Optimization Of Indexable Carbide Inserts

Yah, Fritz Alum January 2009 (has links)
In this project, two broad facets in the design of a methodology for performance optimization of indexable carbide inserts were examined. They were physical destructive testing and software simulation.For the physical testing, statistical research techniques were used for the design of the methodology. A five step method which began with Problem definition, through System identification, Statistical model formation, Data collection and Statistical analyses and results was indepthly elaborated upon. Set-up and execution of an experiment with a compression machine together with roadblocks and possible solution to curb road blocks to quality data collection were examined. 2k factorial design was illustrated and recommended for process improvement. Instances of first-order and second-order response surface analyses were encountered. In the case of curvature, test for curvature significance with center point analysis was recommended. Process optimization with method of steepest ascent and central composite design or process robustness studies of response surface analyses were also recommended.For the simulation test, AdvantEdge program was identified as the most used software for tool development. Challenges to the efficient application of this software were identified and possible solutions proposed. In conclusion, software simulation and physical testing were recommended to meet the objective of the project.
50

none

Lai, Po-chih 18 June 2010 (has links)
Abstract SMT process is the most critical process to influence products quality in electronic assembly house process. Especially,the solder paste printing control is the key process to determine the yield rate of SMT quality. To own the capability to control quality of solder paste printing is the important thing what assembly house have to face it¡C For the purpose of gaining good SMT yield & solder paste printing stability ,the study use six sigma management technique & procedure (DMAIC--Define¡BMeasure¡BAnalyze¡BImprove & Control) make the main factors of solder paste printing¡Aincluding Printing speed¡BScraper pressure¡BStencil clean frequency¡Ato be the experiment factors of DOE(Design of Experiment)¡CThe DOE minimize the experiment number of times and provide a way of 2 levels factorial design combine RSM(Response Surface Methodology) experiment to get the optimization combination of factors¡¦ levels. Then evaluate how the optimization combination of factor levels to influence the quality of SMT¡C The study final found that there are a surprised & satisfied result on SMT yield improvement caused by optimization combination of factors¡¦ levels which 2 levels factorial design combine RSM experiment generated. It can provide the procedure & methodology for SMT assembly house reference to improve yield rate .

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