Orientador: Douglas Altamiro Consolo / Banca: Fernanda Landucci Ortale / Banca: Denise Bértoli Braga / Resumo: O processo de ensino-aprendizagem de uma língua estrangeira está ligado a diversas questões que podem garantir a aquisição de tal língua ou mesmo criar entraves que aumentam a distância entre o aprendiz e a língua-alvo. Assim, questões referentes aos fatores cognitivos, didático-pedagógicos, sociais, econômicos e culturais são significativas em relação à forma como um indivíduo aprende uma determinada língua. O presente trabalho teve como objetivo identificar e descrever as contribuições e os entraves dos meios digitais para a aprendizagem de língua estrangeira por meio da interação entre pares no escopo do projeto Teletandem Brasil: línguas estrangeiras para todos. Tal contexto de aprendizagem baseia-se nos princípios de autonomia e reciprocidade no processo de ensino-aprendizagem à distância, no qual indivíduos falantes de línguas diferentes aprendem e ensinam suas respectivas línguas por meio de atividades de interação na língua a ser aprendida. A investigação da aprendizagem em modelos não-tradicionais de ensino torna-se pertinente a medida que uma reorganização de paradigmas se estabelece na sociedade contemporânea face o desenvolvimento tecnológico observado nos dias de hoje. Tal reorganização implica em uma reestruturação do modo de se produzir e transmitir conhecimento no mundo atual. No que tange às questões educacionais, a era digital demanda uma necessidade latente de que os processos de ensino possam ser reorganizados observando os anseios e exigências que a aprendizagem na pós-modernidade apresenta. Nesse sentido, novas formas de aprendizagem que insiram em seus procedimentos o trabalho sistematizado com as Novas Tecnologias de Informação e Comunicação (NTICs) são necessárias. O trabalho aqui apresentado trata-se de uma pesquisa qualitativa de base etnográfica, na qual foram observados alunos franceses e brasileiros... (resumo completo, clicar acesso eletrônico abaixo) / Abstract: The process of teaching-learning a foreign language is connected to several issues that can ensure the acquisition of such language or even create barriers that increase the distance between the apprentice and the target language. Thus, issues relating to cognitive factors, teaching, educational, social, economic and cultural aspects are significant in relation to how an individual learns a language. This study aimed at identifying and describing the contributions and the barriers digital media present to foreign language learning through peer interaction in the scope of the project Teletandem Brazil: foreign languages for all. This context of learning is based on the principles of autonomy and reciprocity in the teachinglearning at distance, in which speakers of different languages learn and teach their languages through activities of interaction in the language being learned. The research of learning in non-traditional models of education becomes relevant to measure a reorganization of paradigms that is established in contemporary society, facing technological development seen today. This reorganization involves a restructuring of the way to produce and transmit knowledge in the modern world. With regard to educational issues, the digital age need latent demand that the processes of education can be reorganized, observing the desires and demands that learning in post-modernity presents. In this sense, new ways of learning that entering its procedures in the work systematized with the New Technologies of Information and Communication (NTICs) are necessary. The work presented here it is a qualitative research of an ethnographic basis, in which students were observed French and Brazilian in situations of distanct, collaborative and autonomous. During the investigation it was possible to see the latent need that the issues of technology are printed in the teaching-learning process... (Complete abstract click electronic access below) / Mestre

Metabólitos secundários produzidos por actinobactérias são uma inesgotável fonte de compostos com potentes atividades biológicas e estruturas intrínsecas. O desenvolvimento em instrumentação analítica tem contribuído significantemente para acelerar o processo de identificação e caracterização desses metabólitos bioativos. Sem dúvida alguma, a espectrometria de massas (MS) e o seu acoplamento com técnicas de separação, especialmente a cromatografia líquida (UHPLC-MS), tem sido reconhecida como a técnica mais eficiente em análises de produtos naturais. Nesta dissertação foi explorado o potencial da espectrometria de massas como ferramenta analítica para a identificação e caracterização estrutural de fitotoxinas produzidas por actinobactérias isoladas da rizosfera de plantas da caatinga. Foram produzidos noventa extratos de actinobactérias, dos quais quinze apresentaram alguma atividade para o bioensaio da Lemna minor e seis apresentaram atividade para o bioensaio da Chlorella vulgaris. Os extratos brutos ativos das actinobactérias Caat 7-38, Caat 8-6 e Caat 5-29 foram selecionados para caracterização dos compostos ativos, os quais foram isolados empregando o fracionamento guiado por bioensaios. No extrato bruto Caat 7-38, a actinomicina D foi identificada como fitotoxina, ao passo que para o extrato bruto Caat 8-6, foi possível inferir a atividade fitotóxica à presença do griseorhodin A. Já para o extrato bruto Caat 5-29, o composto identificado com atividade fitotóxica apresenta uma estrutura inédita, provavelmente pertencente à classe das anguciclinonas. Foi realizado ainda um estudo para avaliar o efeito da adição de terras raras ao meio de cultivo da actinobacteria Caat 7-38. Para os meios de cultivos contendo neodímio e, principalmente, lantânio ocorreu uma superprodução da actinomicina D, indicando assim, o grande potencial da aplicação das terras raras nos estudos de micro-organismos. / Secondary metabolites produced by actinomycetes are an inexhaustible source of compounds with potent biological activities and intrinsic structures. The development analytical instrumentation has contributed significantly to accelerate the identification and characterization of these bioactive metabolites. Undoubtedly, mass spectrometry (MS) and its coupling with separation techniques, especially liquid chromatography (UHPLC-MS) has been recognized as the most \"efficient\" technique in natural product analysis. In this work was explored the potential of mass spectrometry as an analytical tool for identification and structural characterization of phytotoxins produced by actinomycetes isolated from the rhizosphere of plants from the Caatinga biome. Ninety actinomycetes extracts were produced, of which fifteen showed some activity for the bioassay with Lemna minor and six showed activity for the bioassay with Chlorella vulgaris. The crude active extract of actinomycetes Caat 7-38, Caat 8-6 and Caat 5-29 were selected to characterize the active compounds, which were isolated using bioassay-guided fractionation. In the crude extract Caat 7-38, actinomycin D was identified as phytotoxin, while for crude extract Caat 8-6, it was possible to infer phytotoxic activity to the presence of griseorhodin A. For the crude extract Caat 5-29, the compound identified with phytotoxic activity presents a new structure, probably belonging to the class of anguciclinones. A study to evaluate the effect of addition of rare earths to the culture medium of actinobacteria Caat 7-38 was also carried out. To the culture medium containing neodymium and especially lanthanum occurred overproduction of actinomycin D, thus indicating the great potential of application of rare earths in the studies of microorganisms.

Mass spectrometry is a versatile analytical tool for chemical and biomolecule identification, quantitation, and structural analysis. Tandem mass spectrometry further expands the applications of mass spectrometry, making it more than a mere detector. With tandem mass spectrometry, the mass spectrometer is capable of probing reaction mechanisms, monitoring reaction processes, and performing fast analysis on complex samples. In tandem mass spectrometry, after activation the precursor ions fragment into small fragment ions through one or more pathways, which are affected by the ion’s inherit property, the ion type, and the activation method. To obtain complementary information, one can alter the fragmentation pathway by changing the ion via ion charge manipulation and covalent modification to the ion. Gas-phase ion/ion reactions provide an easy approach to changing ion type and facile modification to the analyte ions. It has been extensively used for spectrum simplification and analyte structural studies. In this dissertation, ion/ion reaction facilitated mass spectrometry methods are studied, and explorations into the method development involving front-end mass spectrometer are discussed.<br>The first work demonstrates a special rearrangement reaction for gas-phase Schiff-base-modified peptides. Gas-phase Schiff-base modification of peptides has been applied to facilitate the primary structural characterization via tandem mass spectrometry. A major or minor fragment pathway related to the novel rearrangement reaction was observed upon in-trap collisional activation of the gas-phase Schiff-base-modified peptides. The rearrangement reaction involves the imine of the Schiff base and a nucleophile present in the polypeptide. The occurrence of the rearrangement reaction is affected by several factors, such as ion polarity, identity of the nucleophile in the peptide (e.g., side chains of lysine, histidine, and arginine), and the position of the nucleophile relative to the imine. The rearrangement reaction does not affect the amount of structural information that can be obtained by collisional activation of the Schiff-base-modified peptide, but when the rearrangement reaction is dominant, it can siphon away signal from the structurally diagnostic processes.<br>Efforts have also been put into the method development of peptide and protein aggregation detection via electrospray ionization mass spectrometry (ESI-MS). People have studied peptide and protein aggregation processes to understand the mechanism of amyloid-related diseases and to control the quality of the peptide and protein pharmaceuticals. ESI-MS is suitable for solution aggregation studies because of its compatibility with solution samples and the straightforward result of the analyte’s oligomeric state on the mass spectrum. However, peak overlap issue and nonspecific aggregation in the ESI process can obscure the result. Here, the application of proton transfer ion/ion reaction to the analyte has been found useful to reduce or eliminate the peak overlap issue. A statistical model based on Poisson statistics has been proposed to deal with the ESI-induced nonspecific aggregation in the droplet and to differentiate the solution-phase aggregation from the droplet-induced aggregation. Factors that affect the accuracy of the statistical model have been discussed with MATLAB simulations.<br>In the era of biological system studies, sample complexity is a challenge every analytical chemist has to face. The analysis of complex sample can be facilitated by the combination of separation techniques outside the mass spectrometer (such as differential mobility spectrometry (DMS)) and ion structure probing techniques inside the mass spectrometer (such as tandem mass spectrometry and gas-phase ion/ion reactions). Here the coupling method between DMS and ion/ion reaction is developed and tested with model peptide systems to demonstrate its possible application in complex sample characterization such as isomer identification.<br>

Esta pesquisa tem como foco a aprendizagem colaborativa realizada por quatro alunos, sendo dois surdos e dois ouvintes, do curso de Letras: Libras da Universidade Federal de Goiás, que ensinaram suas línguas ao seu parceiro em um contexto de aprendizagem de tandem, durante um semestre letivo de 2017. A aprendizagem em tandem é um processo de trocas linguísticas e culturais entre indivíduos que possuem línguas diferentes e que se propõem a ensinar, de forma livre, sua língua a outra pessoa de modo colaborativo. Dessa forma, o participante surdo ensinou libras ao ouvinte, e o ouvinte ensinou ao surdo português escrito. Este estudo busca também investigar se a colaboração pode viabilizar a aprendizagem das línguas mencionadas, visto que são línguas de modalidades linguísticas diferentes. Busca também investigar quais são as estratégias utilizadas pelos pares para esse fim. Trata-se de um estudo de caso qualitativo em que os dados foram coletados por meio de gravação em vídeo das sessões de tandem e entrevistas, analisados sob a luz dos pressupostos da teoria sociocultural e da aprendizagem colaborativa. Os resultados mostram que os alunos usaram algumas estratégias que mediaram o processo de aprendizagem, tais como o uso de objetos e o uso de imagens. Os resultados também mostram que as oportunidades de interação dos alunos surdos com os alunos ouvintes, no contexto estudado, viabilizaram trocas culturais, e que o ensino eficaz para os alunos surdos se faz necessário ocorrer na língua de sinais. Com este estudo, pretendemos suscitar reflexões sobre a aprendizagem colaborativa no contexto de tandem quando temos línguas de modalidades linguísticas diferentes: português – uma língua oral; e libras – uma língua vísuo-espacial, bem como trazer algumas orientações para futuros professores de libras para ouvintes, ou de português para surdos, que venham a ensinar essas línguas em contextos semelhantes. / This study focuses on the collaborative learning between two deaf and two hearing students who take Libras as a major at Universidade Federal de Goiás. They had to teach their language to each other in a tandem collaborative learning processes. The study took place on the first term of 2017. Tandem learning is a process of cultural and linguistic exchanges among individuals who have different languages and are willing to teach each other their language in a collaborative way. Thus, the deaf participant taught Libras to the hearing peer and learned written Portuguese from him/her. This study also aims to investigate if collaboration in tandem context can favor the learning of Libras and Portuguese, since they are languages that have different linguistic modalities. It also investigates which strategies were taken by the participants to teach each other´s language and the perceptions they had about the collaborative learning process in tandem context. It is a qualitative case study whose data were collected through the video recording of the interactions and the interviews. Data analysis shows that the students used some strategies that mediated the learning process, such as the use of realia, the use of images, etc. The results also show that the interactions favored not only linguistic knowledge, but also cultural exchanges and that the deaf students ought to be taught by the use of sign language. This study aims to bring some reflections on the learning process in tandem context when the languages involved have different linguistic modalities, as well as bring some guidance to future language teachers who might teach those languages in similar contexts.

<div>Amongst the various classes of mass analyzers, the quadrupole ion trap (QIT) is by far the most versatile. Although it can achieve only modest resolution (unit) and mass accuracy (101-102 ppm), it has high sensitivity and selectivity, can operate at pressures exceeding 10-3 torr, is tolerant to various electrode imperfections, and has single analyzer tandem mass spectrometry (MS/MS) capabilities in the form of product ion scans. These characteristics make the QIT ideal for mass spectrometer miniaturization, as most of the fundamental performance metrics of the QIT do not depend on device size. As such, the current drive in miniature systems is to adopt miniature ion traps in various forms – 3D, linear, toroidal, rectilinear, cylindrical, arrays, etc.</div><div><br></div><div>Despite being one of the two common mass analyzers with inherent MS/MS capabilities (the other being the Fourier transform ion cyclotron resonance mass spectrometer), it is commonly accepted that the QIT cannot perform one-dimensional precursor ion scans and neutral loss scans - the other two main MS/MS scan modes - or two-dimensional MS/MS scans. The former two are usually conducted in triple quadrupole instruments in which a first and third quadrupole are used to mass select precursor and product ions while fragmentation occurs in an intermediate collision cell. The third scan can be accomplished by acquiring a product ion scan of every precursor ion, thus revealing the entire 2D MS/MS data domain (precursor ion m/z vs. product ion m/z). This, however, is not one scan but a set of scans. Because the ion trap is a tandem-in-time instrument rather than a tandem-in-space analyzer, precursor ion scans, neutral loss scans, and 2D MS/MS are, at best, difficult.</div><div><br></div><div>Yet miniature mass spectrometers utilizing quadrupole ion traps for mass analysis would perhaps benefit the most from precursor scans, neutral loss scans, and 2D MS/MS because they generally have acquisition rates (# scans/s) an order of magnitude lower than their benchtop counterparts. This is because they usually use a discontinuous atmospheric pressure interface (DAPI) to reduce the gas load on the backing pumps, resulting in a ~1 scan/s acquisition rate and making the commonly-used data-dependent acquisition method (i.e. obtaining a product ion scan for every abundant precursor ion) inefficient in terms of sample consumption, time, and instrument power. Precursor and neutral loss scans targeting specific molecular functionality of interest - as well as 2D MS/MS – are more efficient ways of moving through the MS/MS data domain and thus pair quite readily with miniature ion traps.</div><div><br></div><div>Herein we demonstrate that precursor ion scans, neutral loss scans, and 2D MS/MS are all possible in a linear quadrupole ion trap operated in the orthogonal double resonance mode on both benchtop and portable mass spectrometers. Through application of multiple resonance frequencies matching the secular frequencies of precursor and/or product ions of interest, we show that precursor ions can be fragmented mass-selectively and product ions ejected simultaneously, preserving their relationship, precursor ion -> product ion + neutral, in the time domain and hence allowing the correlation between precursor and product ions without prior isolation. By fixing or scanning the resonance frequencies corresponding to the targeted precursor and product ions, a precursor ion scan or neutral loss scan can be conducted in a single mass analyzer. We further show that 2D MS/MS - acquisition of all precursor ion m/z values and a product ion mass spectrum for every precursor ion, all in a single scan - is possible using similar methodology. These scan modes are particularly valuable for origin-of-life and forensic applications for which the value of miniature mass spectrometers is readily evident.</div>

Protein identification using tandem mass spectrometry (MS/MS) has proven to be an effective way to identify proteins in a biological sample. An observed spectrum is constructed from the data produced by the tandem mass spectrometer. A protein can be identified if the observed spectrum aligns with the theoretical spectrum. However, data generated by the tandem mass spectrometer are affected by errors thus making protein identification challenging in the field of proteomics. Some of these errors include wrong calibration of the instrument, instrument distortion and noise. In this thesis, we present a pre-processing method, which focuses on the removal of noisy data with the hope of aiding in better identification of proteins. We employ the method of binning to reduce the number of noise peaks in the data without sacrificing the alignment of the observed spectrum with the theoretical spectrum. In some cases, the alignment of the two spectra improved.

OBJECTIVE The purpose of this study was to examine the stability of a generic lansoprazole product in a 3 mg/mL sodium bicarbonate suspension under room temperature and refrigerated conditions. METHODS Lansoprazole suspensions (3 mg/mL) were prepared in triplicate using an 8.4% sodium bicarbonate vehicle for each storage condition (room temperature and refrigerated). During 1 month, samples from each replicate were periodically removed and analyzed for lansoprazole concentration by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Each sample was spiked with 10 mg/L omeprazole to serve as the internal standard. A positive electrospray LC-MS/MS method was validated over the calibration range of 5 to 25 mg/L using Food and Drug Administration Guidance. The identities of the analyte and internal standard in the samples were verified by monitoring the MS/MS transitions of m/z 370 to m/z 252 and m/z 346 to m/z 198 for lansoprazole and omeprazole, respectively. Additionally, the pH of the suspensions was monitored throughout the study. RESULTS The stability of lansoprazole in the oral sodium bicarbonate suspension under refrigeration is compromised prior to what has been previously reported in the literature. Samples kept at room temperature lost >10% of the lansoprazole after 48 hours compared with the refrigerated samples, which maintained integrity up to 7 days. No statistically significant difference was found between the pH of the room temperature and refrigerated suspension samples, indicating that this factor is not the cause for the differences in stability at these two conditions. CONCLUSIONS This study suggests that the extemporaneously compounded lansoprazole oral suspension prepared in 8.4% sodium bicarbonate should not be stored in plastic oral syringes longer than 48 hours at room temperature and no longer than 7 days when refrigerated. These data indicate an expiration time earlier than that previously reported for the refrigerated product (14 days).

Using both quantitative and qualitative methods of inquiry, this dissertation study undertakes an exploration of the dynamics of the social interaction in discourse co-constructed by pairs of college students in telecollaborative tandem exchanges. Two groups of participants, Mexican learners of English as a foreign language and American learners of Spanish as a foreign language, participated in video-based telecollaborative tandem exchanges where they worked in pairs to discuss topics assigned by their instructors, communicating half the time in Spanish and half in English. According to the principle of reciprocity in tandem learning, the participants switch between the roles of native speaker (NS) expert and non-native speaker (NNS) learner as they invest equal time, effort, and interest in each language part of the chats. Grounded in sociocultural theory (SCT) for second language acquisition (SLA), this study addresses research questions pertaining to (1) the distribution of talk between the members of each pair and between the language parts of the exchange, (2) the distribution of interactional resources deployed by the members of each pair to establish and maintain intersubjectivity and build a relationship, and (3) the individual experiences of participants regarding their positioning in and perspectives of the exchange. Addressing the three research questions allowed the researcher to look at the telecollaborative tandem exchanges from the perspectives of language production, social aspects of interaction, and individual experiences and perspectives to gather a deeper understanding of the tandem context. The analysis of three data sources—survey responses, chat transcripts from one chat of the semester-long telecollaborative tandem project, and post-project participant interviews—shows that the principle of reciprocity posited by tandem theorists as equal time, effort, and interest in each language part underestimates the complexity of the construct as it was created by the participants in the telecollaborative tandem interactions examined in this dissertation study. A mixed methods approach allowed the researcher to deconstruct and reconsider the construct of reciprocity in telecollaborative tandem learning. The telecollaborative tandem exchanges examined in this study were not reciprocal between language parts of the exchange in terms of language production, use of interactional resources, or tandem participant positioning. Instead, they presented complex pair relationships that used language differently in each language part to establish and maintain intersubjectivity, as well as the strong desire of the participants to position themselves and their partners as peers rather than take on the roles assumed to characterize the tandem context; that is, NS as expert and NNS as learner. In accordance with these findings, telecollaborative tandem learning should be approached with an open understanding of the concept of reciprocity in which the participants co-construct their relationship through meaningful social dialogue as peers, rather than through the roles of NS expert and NNS learner. Based on the findings of this study, the expert–learner model of reciprocity may be too rigid and too static for the dynamic context of telecollaborative tandem learning.

The fabrication of low cost, high efficiency solar cells is imperative in competing with existing energy technologies. Many research groups have explored using III-V materials and thin-film technologies to create high efficiency cells; however, the materials and manufacturing processes are very costly as compared to monocrystalline silicon (Si) solar cells. Since commercial Si solar cells typically have efficiencies in the range of 17-19%, techniques such as surface texturing, depositing a surface-passivating film, and creating multi-junction Si cells are used to improve the efficiency without significantly increasing the manufacturing costs. This research focused on two of these techniques: (1) a tandem junction solar cell comprised of a thin-film perovskite top cell and a wafer-based Si bottom cell, and (2) Si solar cells with single- and double-layer silicon nitride (SiNx) anti-reflection coatings (ARC). The perovskite/Si tandem junction cell was modeled using a Matlab analytical program. The model took in material properties such as doping concentrations, diffusion coefficients, and band gap energy and calculated the photocurrents, voltages, and efficiencies of the cells individually and in the tandem configuration. A planar Si bottom cell, a cell with a SiNx coating, or a nanostructured black silicon (bSi) cell can be modeled in either an n-terminal or series-connected configuration with the perovskite top cell. By optimizing the bottom and top cell parameters, a tandem cell with an efficiency of 31.78% was reached. Next, planar Si solar cells were fabricated, and the effects of single- and double-layer SiNx films deposited on the cells were explored. Silicon nitride was sputtered onto planar Si samples, and the refractive index and thicknesses of the films were measured using ellipsometry. A range of refractive indices can be reached by adjusting the gas flow rate ratios of nitrogen (N2) and argon (Ar) in the system. The refractive index and thickness of the film affect where the minimum of the reflection curve is located. For Si, the optimum refractive index of a single-layer passivation film is 1.85 with a thickness of 80nm so that the minimum reflection is at 600nm, which is where the photon flux is maximized. However, using a double-layer film of SiNx, the Si solar cell performance is further improved due to surface passivation and lowered surface reflectivity. A bottom layer film with a higher refractive index passivates the Si cell and reduces surface reflectivity, while the top layer film with a smaller refractive index further reduces the surface reflectivity. The refractive indices and thicknesses of the double-layer films were varied, and current-voltage (IV) and external quantum efficiency (EQE) measurements were taken. The double-layer films resulted in an absolute value increase in efficiency of up to 1.8%.

Les réactions de métathèse sont des méthodes performantes pour la création de doubles liaisons carbone-carbone et leurs popularités s'expliquent par l'accessibilité des catalyseurs nécessaires à celles-ci et par la facilité de mise en oeuvre de ces réactions. Elles ont par ailleurs trouvé de nombreuses applications dans la synthèse de molécules naturelles.Les aurisides A et B sont des molécules naturelles d'origine marine isolées du lièvre des mers Dolabella Auricularia en 1996. Ces macrolides présentent une activité cytotoxique intéressante contre des lignées de cellules cancéreuses HeLaS3 avec des valeurs d'IC50 de 0,17 et 1,2 μg/mLrespectivement.Nous avons dans un premier temps développé une voie d'accès au fragment C1-C9 des composés naturels en se basant sur la réaction de métathèse croisée des oléfines. Une étude sur le mode formation de la structure macrocylique par un processus séquentiel impliquant une réaction demétathèse cyclisante et une cétalisation transannulaire a ensuite été conduite sur des composés modèles permettant l'obtention de macrolactones analogues. Cette méthodologie a ensuite été appliquée à la synthèse stéréocontrôlée du squelette carboné des aurisides seulement dépourvu de sa chaîne latérale attaché sur l'atome de carbone C13.Enfin la réaction de métathèse croisée a également été exploitée dans un processus tandem avec celle d'hydrogénation pour la synthèse énantiosélective du 6-hydroxydodécanoate de pentadécyle,composant principal de l'huile essentiel Ylang-Ylang, et qui est également utilisé en médecine traditionnelle contre le choléra.