A hidroxiapatita (HA) tem sido amplamente utilizada como material de implante por possuir alta similaridade com a composição dos ossos e ter capacidade de formar ligações químicas fortes com o tecido ósseo. Entretanto, a adsorção fácil de moléculas orgânicas (proteínas, aminoácidos e polissacarídeos) pela HA também favorece a adsorção e replicação de bactérias, aumentando os casos de infecções relacionados a esse biomaterial. Visando contribuir para o avanço de novos biomateriais com propriedades antibacterianas, foram produzidas neste trabalho hidroxiapatitas contendo nanopartículas de prata (AgNPs) com diferentes proporções (0,01; 0,05; 0,10 e 0,25% m/m). A primeira etapa do trabalho consistiu na obtenção do pó de HA por precipitação química e na produção de AgNPs em suspensões coloidais por meio de síntese que utiliza a quitosana como agente redutor e estabilizante. Na segunda etapa, as AgNPs foram adsorvidas na HA pelo método de imersão do pó usando um dos coloides sintetizados, obtendo-se quatro hidroxiapatitas contendo AgNPs (HA-AgNPs) nas formas de pó e disco. Na terceira e última etapa, os materiais produzidos foram caracterizados utilizando diversas técnicas e os pós (HA e HA-AgNPs) foram submetidos a avaliações in vitro. O efeito antibacteriano foi avaliado frente a cepas de S. aureus e E. coli utilizando métodos qualitativos e quantitativos. A adesão bacteriana sobre a superfície dos discos foi observada por microscopias eletrônica de varredura (MEV) e confocal de varredura a laser. A citotoxicidade in vitro foi avaliada utilizando cultura de células contendo linhagem de osteoblastos (MG-63). Nesse ensaio, a viabilidade dos osteoblastos foi estudada usando o teste da resazurina; a atividade enzimática foi investigada através da fosfatase alcalina (ALP); e a adesão dos osteoblastos foi observada por MEV. Os resultados mostraram que a HA produzida é nanométrica e que as AgNPs sintetizadas são estáveis e esféricas, com diâmetros variando entre 5-10 nm. Técnicas de MEV, EDS e ICP-AES confirmaram a presença de prata nas HA-AgNPs. As demais caracterizações não mostraram alterações relevantes na estrutura, morfologia e características de superfície (hidrofobicidade e carga líquida). No entanto, a atividade antibacteriana dos materiais mostrou-se eficiente para ambas as cepas e com uma redução de 99,9% das colônias bacterianas em quase todos os materiais já nas primeiras 4 h. Também foi encontrado que a eliminação foi maior tanto para E. coli quanto utilizando materiais em pó. O estudo da adesão bacteriana confirmou os resultados anteriores mostrando efeito superior para quase todas HA-AgNPs produzidas comparado a HA, exceto para o material com menor proporção de AgNPs (0,01% m/m). Por outro lado, os testes de viabilidade, ALP e adesão demonstraram que a HA-AgNPs com maior quantidade de AgNPs (0,25% m/m) tem um efeito negativo sobre os osteoblastos. Considerando ambos os efeitos de citotoxicidade e antibacteriano, aliado a metodologia simples e de baixo custo envolvido na produção desses materiais, sugere-se que a HA contendo entre 0,05 0,10% m/m das AgNPs sintetizada pode ser a mais favorável para o desenvolvimento proposto visando futuras aplicações biomédicas. / Hydroxyapatite (HA) has been widely used as implant material due to its high similarity with the bone composition and its capacity to form strong chemical bonds with the bone tissue. However, the easy adsorption of organic molecules (proteins, amino acids and polysaccharides) by the HA also favors bacteria adsorption and replication, increasing the cases of infection related to this biomaterial. Aiming to contribute to the advancement of new biomaterials with antibacterial properties, were produced in this work hydroxyapatites containing silver nanoparticles (AgNPs) with different ratios (0.01, 0.05, 0.10 and 0.25% m/m). The first step of this work consisted in obtaining the HA powder by chemical precipitation and production of AgNPs colloidal suspensions by synthesis using chitosan as a reducing agent and stabilizer. In the second step, the AgNPs were adsorbed to the HA matrix by the powder immersion method using onde of the synthesized colloids, resulting in four hydroxyapatites containg AgNPs (HA-AgNPs) in disk and powder forms. In the third and final step, the materials produced were characterized using several techniques, with the powders (HA and HA-AgNPs) evaluated in vitro. The antibacterial effect was evaluated against strains of S. aureus and E. coli using qualitative (ágar diffusion test) and quantitative (bacterial colony counts) methods. The bacterial adhesion over the disks surface were observed by Scanning Electron Microscopy (SEM) and confocal laser scanning microscopy. Cytotoxicity was evaluated in vitro using cell culture containing the osteoblast lineage (MG- 63). In this assay, osteoblasts viability was studied using the resazurin test; the enzyme activity was investigated by alkaline phosphatase (ALP), and osteoblast adhesion was observed by SEM. The results showed that the HA produced is nanometric and the synthesized AgNPs are stable and spherical with diameters ranging from 5-10 nm. SEM, EDS and ICP-AES techniques confirmed the presence of silver in the HA-AgNPs. The others characterizations showed no significant changes in the structure, morphology and surface characteristics (hydrophobicity and net charge). However, the materials antibacterial activity was effective for both strains and with reduction of 99.9% of bacterial colonies in almost all materials within the first 4 h. It was also found that the removal was as great for E. coli as for powder materials. The bacterial adhesion study confirmed previous results showing superior effect for almost all HA-AgNPs produced compared to HA, except for the material with the lowest proportion of AgNPs (0.01% m/m). On the other hand, viability tests, ALP and adhesion demonstrated that HA-AGNPS with higher AGNPS quantities (0.25% m/m) has a negative effect on osteoblasts. Considering both cytotoxicity and antibacterial effects, combined with the simple methodology and low cost involved in the production of these materials, it is suggested that the HA containing synthesized AgNPs ranging from 0.05 to 0.10% m/m can be the most favorable for the development of the proposed material for future biomedical applications.

There is a critical need for college students to receive an education that fosters global learning in preparation for life in an increasingly interdependent and interconnected world. Universities recognize this need and endeavor to provide a range of programs that target global knowledge and skills, and meet the needs of traditional and non-traditional students. Domestic foreign language immersion programs can contribute to student global learning and development by providing students with an opportunity to participate in a rich global learning experience in the U.S. While some researchers have investigated impacts of domestic foreign language immersion on language proficiency, few studies of other kinds of global learning outcomes are available, and research is needed to gain an understanding of program impacts and make improvements. The purpose of this study was to determine the extent to which participation in a domestic foreign language immersion program was perceived to influence global learning and development. The study used a mixed-methods design that incorporated as a key instrument a retrospective survey of former participants in a university-level domestic foreign language immersion program. Perspectives from short-term study abroad, foreign languages, transformative learning, and global citizenship informed the research. The study found that participants in a domestic foreign language immersion program perceived influence in all three domains of global development. The degree of perceived influence was similar in the three domains except in the area of social responsibility, which received a significantly lower rating. Finally, student characteristics, including age, language level, prior international or other intercultural experience, and on/off-campus residence were not associated with perceived program influence. A qualitative analysis helped explain these findings.

Figures from the 2010 Census indicate that there are 50.5 million Latinos (16% of the total population) living in the United States (US) today. From 2000 to 2010, the Latino population experienced a very rapid growth rate of 43%, which accounted for over half the total population growth. More and more Latino students are entering our public schools and face the reality that 62 years after the Brown V. Board of Education ruling to integrate schools and equalize educational opportunities, schools are more racially and economically segregated and more unequal than they were more than half a century ago. As a group, Latinos continue to struggle academically and there is a large academic achievement gap between Latino students and White students. Using the lens of Latino Critical race theory, this narrative study was an attempt to understand the educational experience of five Latino students in a two-way immersion program within a racialized public education system in which negative stereotypes, such as lack of intellectual abilities, could create a threatening environment hindering their academic success. This narrative inquiry study sought to understand how, if at all, Latino students in a fifth grade two-way immersion program experienced anxiety about the ways they believe to be perceived in the classroom and school settings by their teachers and other classmates. Finding of this study confirmed the relative success of two-way immersion programs educating Latino students and highlighted the urgent need to conduct more research in bilingual settings trying to understand the role stereotype threat might play in the educational experience of Latino students. The fact that Latino students were still lagging behind their native English-speaking counterparts in the TWI program is a reality that must be researched further to understand the lived experiences of Latino students in bilingual programs.

Research in the field of second language acquisition in the past five to ten years has focused on individual variation in language learning, and has examined such learner variables as learning styles, personality characteristics, learning strategies, and learner beliefs about the nature of language learning. Recently, research on individual learners has broadened to include a greater focus on the contexts of language learning and to explore the interactions between individual learners and the socio-cultural environment in investigations of these learner variables.This study has two purposes. The first is to investigate the language learning of novice level second language learners in a language and culture immersion program. The six college-age learners of Spanish who participated in an eight-week language and culture immersion program in Mexico are the focus of the case studies. The research focuses on five areas of learner variation: learner beliefs and philosophies about the nature of language learning, approaches to vocabulary learning, classroom behaviors, speaking for communication, and cultural adjustment.The second purpose of the study is to explore the use of multiple approaches to research on individual variation. The research framework for the study is ethnographic and the study employs a multi-methodological approach to data collection over an extended period of time in several language learning contexts. The research procedures used in the studyinclude participant observation, interviews, language learning journals, questionnaires, retrospective analysis of videotaped clips, and standardized instruments such as the Modern Language Aptitude Test, the Strategy Inventory for Language Learning, the Myers-Briggs Type Indicator, and the ACTFL Oral Proficiency Interview. / Department of English

A hidroxiapatita (HA) tem sido amplamente utilizada como material de implante por possuir alta similaridade com a composição dos ossos e ter capacidade de formar ligações químicas fortes com o tecido ósseo. Entretanto, a adsorção fácil de moléculas orgânicas (proteínas, aminoácidos e polissacarídeos) pela HA também favorece a adsorção e replicação de bactérias, aumentando os casos de infecções relacionados a esse biomaterial. Visando contribuir para o avanço de novos biomateriais com propriedades antibacterianas, foram produzidas neste trabalho hidroxiapatitas contendo nanopartículas de prata (AgNPs) com diferentes proporções (0,01; 0,05; 0,10 e 0,25% m/m). A primeira etapa do trabalho consistiu na obtenção do pó de HA por precipitação química e na produção de AgNPs em suspensões coloidais por meio de síntese que utiliza a quitosana como agente redutor e estabilizante. Na segunda etapa, as AgNPs foram adsorvidas na HA pelo método de imersão do pó usando um dos coloides sintetizados, obtendo-se quatro hidroxiapatitas contendo AgNPs (HA-AgNPs) nas formas de pó e disco. Na terceira e última etapa, os materiais produzidos foram caracterizados utilizando diversas técnicas e os pós (HA e HA-AgNPs) foram submetidos a avaliações in vitro. O efeito antibacteriano foi avaliado frente a cepas de S. aureus e E. coli utilizando métodos qualitativos e quantitativos. A adesão bacteriana sobre a superfície dos discos foi observada por microscopias eletrônica de varredura (MEV) e confocal de varredura a laser. A citotoxicidade in vitro foi avaliada utilizando cultura de células contendo linhagem de osteoblastos (MG-63). Nesse ensaio, a viabilidade dos osteoblastos foi estudada usando o teste da resazurina; a atividade enzimática foi investigada através da fosfatase alcalina (ALP); e a adesão dos osteoblastos foi observada por MEV. Os resultados mostraram que a HA produzida é nanométrica e que as AgNPs sintetizadas são estáveis e esféricas, com diâmetros variando entre 5-10 nm. Técnicas de MEV, EDS e ICP-AES confirmaram a presença de prata nas HA-AgNPs. As demais caracterizações não mostraram alterações relevantes na estrutura, morfologia e características de superfície (hidrofobicidade e carga líquida). No entanto, a atividade antibacteriana dos materiais mostrou-se eficiente para ambas as cepas e com uma redução de 99,9% das colônias bacterianas em quase todos os materiais já nas primeiras 4 h. Também foi encontrado que a eliminação foi maior tanto para E. coli quanto utilizando materiais em pó. O estudo da adesão bacteriana confirmou os resultados anteriores mostrando efeito superior para quase todas HA-AgNPs produzidas comparado a HA, exceto para o material com menor proporção de AgNPs (0,01% m/m). Por outro lado, os testes de viabilidade, ALP e adesão demonstraram que a HA-AgNPs com maior quantidade de AgNPs (0,25% m/m) tem um efeito negativo sobre os osteoblastos. Considerando ambos os efeitos de citotoxicidade e antibacteriano, aliado a metodologia simples e de baixo custo envolvido na produção desses materiais, sugere-se que a HA contendo entre 0,05 0,10% m/m das AgNPs sintetizada pode ser a mais favorável para o desenvolvimento proposto visando futuras aplicações biomédicas. / Hydroxyapatite (HA) has been widely used as implant material due to its high similarity with the bone composition and its capacity to form strong chemical bonds with the bone tissue. However, the easy adsorption of organic molecules (proteins, amino acids and polysaccharides) by the HA also favors bacteria adsorption and replication, increasing the cases of infection related to this biomaterial. Aiming to contribute to the advancement of new biomaterials with antibacterial properties, were produced in this work hydroxyapatites containing silver nanoparticles (AgNPs) with different ratios (0.01, 0.05, 0.10 and 0.25% m/m). The first step of this work consisted in obtaining the HA powder by chemical precipitation and production of AgNPs colloidal suspensions by synthesis using chitosan as a reducing agent and stabilizer. In the second step, the AgNPs were adsorbed to the HA matrix by the powder immersion method using onde of the synthesized colloids, resulting in four hydroxyapatites containg AgNPs (HA-AgNPs) in disk and powder forms. In the third and final step, the materials produced were characterized using several techniques, with the powders (HA and HA-AgNPs) evaluated in vitro. The antibacterial effect was evaluated against strains of S. aureus and E. coli using qualitative (ágar diffusion test) and quantitative (bacterial colony counts) methods. The bacterial adhesion over the disks surface were observed by Scanning Electron Microscopy (SEM) and confocal laser scanning microscopy. Cytotoxicity was evaluated in vitro using cell culture containing the osteoblast lineage (MG- 63). In this assay, osteoblasts viability was studied using the resazurin test; the enzyme activity was investigated by alkaline phosphatase (ALP), and osteoblast adhesion was observed by SEM. The results showed that the HA produced is nanometric and the synthesized AgNPs are stable and spherical with diameters ranging from 5-10 nm. SEM, EDS and ICP-AES techniques confirmed the presence of silver in the HA-AgNPs. The others characterizations showed no significant changes in the structure, morphology and surface characteristics (hydrophobicity and net charge). However, the materials antibacterial activity was effective for both strains and with reduction of 99.9% of bacterial colonies in almost all materials within the first 4 h. It was also found that the removal was as great for E. coli as for powder materials. The bacterial adhesion study confirmed previous results showing superior effect for almost all HA-AgNPs produced compared to HA, except for the material with the lowest proportion of AgNPs (0.01% m/m). On the other hand, viability tests, ALP and adhesion demonstrated that HA-AGNPS with higher AGNPS quantities (0.25% m/m) has a negative effect on osteoblasts. Considering both cytotoxicity and antibacterial effects, combined with the simple methodology and low cost involved in the production of these materials, it is suggested that the HA containing synthesized AgNPs ranging from 0.05 to 0.10% m/m can be the most favorable for the development of the proposed material for future biomedical applications.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Cada año, millones de estudiantes estadounidenses participan en programas de inmersión, de intercambio, o de una estancia a largo plazo en otros países. Para saber el valor total de una experiencia de estudio en el extranjero, es necesario escuchar la voz y las percepciones de los participantes de su experiencia y determinar cómo estas percepciones afectan el sentimiento de éxito en el extranjero. En este estudio cualitativo se sigue a ocho estudiantes del nivel secundario en un intercambio en Barcelona, España, a fin de identificar los elementos principales que afectan la percepción de la ganancia lingüística y cultural por parte del estudiante y del profesor en el contexto de un estudio en el extranjero. Se presentan que 1) las ideas de la adquisición de segunda lengua vienen del aula tradicional, 2) las oportunidades sociales y el desarrollo de redes sociales resultan en práctica auténtica de las destrezas comunicativas, 3) la motivación alta por parte del estudiante es una característica común de estudiantes que participan en un estudio en el extranjero y esta característica (motivación alta) les ayuda a sobrevivir los desafíos naturales del extranjero, y 4) el estudio en el extranjero ni produce hablantes nativos ni crea estudiantes que se comprometen a continuar con el estudio del español.

No description available.

The purpose of this study was to determine the English language skills of minority language children (experimental group) in a early total French Immersion program by comparing them with those of English-speaking children in French Immersion (English control group), and with those of minority language children in a regular English program (minority control group). Ten grade one children comprised each of the three groups of children. Listening comprehension of English was assessed using two standardized tests of English comprehension (the Peabody Picture Vocabulary Test and the Token Test for Children). English speaking skills were assessed using the Clark-Madison Test of Oral Language (a standardized test) and a ten to fifteen minute language sample. English metalinguistic skills were assessed with a phoneme deletion task used by Rosner & Simon (1971) and with two tasks used by Pratt, Tunmer & Bowey (1984): a morpheme correction task and a word order correction task. Questionnaires were used to assess attitudes towards the minority language and culture and to determine the children's home and language background. It was hypothesized that the English language skills of the experimental group would be at least as good as those of the English control group and the minority control group. The results supported the hypotheses. The experimental group did as well as the English control group on all of the measures of English comprehension and production tested. The minority control group scored lower than the English control group on all measures of English comprehension and production. They scored lower than the experimental group on the comprehension of complex commands and on the Clark-Madison Test of Oral Language. The three groups scored similarly on all of the metalinguistic tasks except on the morpheme correction task, where the minority control group scored lower than the English control group. Results support the suitability of early total French Immersion for minority language children who have their first language and culture valued and maintained. / Medicine, Faculty of / Audiology and Speech Sciences, School of / Graduate

Although first-generation college students and fratemity and sorority members have been explored and described independently within higher education research, less is known about the overlap in these two experiences and the culminating student population which provides the focus for this study. This study investigates the college experiences of six first-generation college students who are members of Greek-letter organizations at universities on the west coast. Case study methodology and community cultural wealth (Y osso, 2005) are used to analyze semistructured, in-depth interviews and provide rich descriptions, which inform an understanding of why students join Greek-letter organizations, the nature of their experience, and how their membership may influence how they experience college. Although participants did not describe their experience in college or in a Greek-letter organization as particularly unique as a result of their generational status, findings indicate a substantial gain in social and navigational capital, which they intended to utilize during and after their college years. Findings also indicate that due to the involvement in the Greek community, first-generation college students experienced college with a greater commitment to persist. By utilizing community cultural wealth to describe and explain first-generation college students in Greek-letter organizations, it emerges as a relevant framework for student affairs educators to incorporate into their practice.