Ulm, Univ., Diss., 2008.

Arsenic exposure in humans has been implicated in the development of a myriad of non-cancerous and cancerous diseases. A reductionist approach to understanding this unusual phenomenon would suggest that arsenic-induced perturbation of a small number of fundamental biological processes could manifest as this diverse array of disease endpoints. Endocytosis is a fundamental cellular process involved in the internalization and transport of various extracellular molecules and membranous components. BEAS-2B, a human bronchial epithelial cell line, was used to characterize the effects of chronic arsenite exposure on endocytosis. Fluorophore-labeled bovine albumin, human transferrin, and human low-density lipoprotein (LDL) were the substrates utilized to measure endocytosis in BEAS-2B cells. The uptake of albumin in unexposed BEAS-2B cells is both dose-dependent and temperature sensitive. Chronic arsenite exposure in BEAS-2B cells increased the uptake of albumin by 3.4-fold after 8 hours of uptake relative to unexposed BEAS-2B cells. Pharmacological studies utilizing endocytosis inhibitors suggested that the uptake of albumin in both unexposed and arsenite-exposed BEAS-2B cells occurs through a combination of receptor-mediated endocytosis and macropinocytosis. Chronic arsenite exposure in BEAS-2B cells also increased the endocytic uptake of transferrin by 2.9-fold at 30 minutes and LDL by 1.3-fold at 2 hours relative to unexposed BEAS-2B cells. Together, the data suggests that chronic arsenite exposure can increase the rate of endocytosis. This novel finding could add mechanistic insight to the conundrum of arsenic-associated human diseases.

Streptococcus agalactiae (Streptocoque du Groupe B, SGB) est une bactérie pathogène opportuniste à Gram-positif responsable principalement d’infections néonatales. Les études épidémiologiques ont montré que les souches appartenant au complexe clonal 17 (ST-17) sont responsables de 80% des cas de méningites tardives. La génomique comparative a permis de mettre en évidence des gènes codant pour des protéines de surface spécifiques au clone ST-17 comme les adhésines Srr2 et HvgA. On y trouve également un locus codant pour un pilus spécifique appelé PI-2b, qui constitua l’objet principal de cette thèse. Ce locus PI-2b est ubiquitaire dans les souches ST-17, mais on le retrouve également dans quelques souches humaines non-ST-17 comme la souche A909 ainsi que dans les souches bovines. Dans la première partie de ce travail, nous avons comparé l’expression du pilus PI-2b dans les souches ST-17 versus non-ST-17. L’expression du locus PI-2b, bien que variable au sein du complexe ST-17, est plus faible que dans les souches non-ST-17. Dans la souche représentative du ST-17 BM110, l’expression du gène spb1codant pour la piline majeure est 4-6 fois plus faible que dans la souche A909. Nous avons montré que cet effet est dû à la présence d’une séquence de 43 paires de base en amont du locus PI-2b, formant une structure de type tige-boucle, qui empêche la transcription provenant du locus situé en amont codant pour l’antigène B. Grâce à des expériences de fusion transcriptionnelle avec un gène rapporteur codant pour la GFP, nous avons montré qu’une région étendue du promoteur ainsi que des facteurs spécifiques à S. agalactiae sont nécessaires pour l’expression maximale du locus PI-2b. Le niveau maximal de transcription du pilus PI-2b est observé à 37 °C. L’ensemble de nos résultats suggère une régulation complexe de l’expression du locus PI-2b, dont l’expression plus faible dans les souches ST-17, pourrait conférer aux bactéries la capacité d’échapper au système immunitaire de l’hôte et de disséminer plus efficacement. La deuxième partie de ce travail a porté sur le rôle des gènes orf, lep et san1519 dont la fonction sur la biosynthèse du pilus n’était pas connue. Nous avons montré que les gènes orf et lep sont importants pour l’expression et la polymérisation du pilus PI-2b. Nous avons montré que lep code pour une signal peptidase fonctionnelle qui participe à la maturation de la piline majeure. Quant à orf, nos autres résultats ainsi le chevauchement traductionnel entre ce gène et lep, conservé dans d’autres espèces de streptocoques, suggèrent un rôle dans la stabilisation des ARNm / Streptococcus agalactiae (also known as Group B Streptococcus, GBS) is an opportunistic Gram-positive pathogen responsible for severe invasive infections, especially in neonates. GBS strains belonging to the ST-17 sequence type are responsible for 80% of late-onset neonatal meningitis. Genomic comparison of ST-17 strains to non-ST-17 GBS isolates revealed a few surface proteins that are characteristic of ST-17 clone, such as HvgA and Srr2, which contribute to colonization and dissemination. Similarly, the PI-2b type pilus is conserved in ST-17 strains and the main goal of this PhD project was to decipher the role of this pilus in the physiopathology of ST-17 strains. In the first part of this work, we compared the expression of the PI-2b pilus in our ST-17 representative strain BM110, and a non-ST-17 human clinical isolate, A909. We showed that PI-2b expression, although variable, was lower in ST-17 isolates as compared to non ST17 isolates. In the representative strain BM110, we demonstrated that the lower expression was be due to the presence of a 43-base pair (bp) hairpin-like structure in the upstream region of PI-2b, preventing read-through transcription from upstream antigen B (AgB) operon. Furthermore, gene reporter assays to characterize the Ppi-2b promoter region revealed the requirement of an extended 5’ region and of GBS-specific regulatory factors to drive PI-2b transcription. PI-2b transcription was shown to be maximal at 37 °C. Collectively our results suggest a complex regulation of PI-2b expression in ST-17 clinical isolates, that may confer a selective advantage in the human host either by reducing host immune responses and/or increasing their dissemination potential.In the second part of this work, we sought to investigate the role of the putative adhesin AP1-2b, and the two accessory genes lep and orf in the biosynthesis of PI-2b pilus. We showed that both orf and lep are important for PI-2b expression. Our results suggest that Lep is a functional signal peptidase involved in the optimal processing of the major PI-2b pilin. The role of orf remains to be uncovered

Studien behandlar kompetenser och kunskapsnivåer hos gymnasieelever inom geometriavsnittet, matematikkurs 2b. Syftet är att undersöka i vilken utsträckning elever behärskar de matematiska kompetenserna och vilken kunskapsnivå inom avsnittet geometri elever uppnår på ett kunskapstest som konstruerats av uppgifter från nationella prov och elevernas läromedelsbok. Datainsamlingen genomfördes på en svensk gymnasieskola och omfattar 47 elever från två olika klasser i årskurs 2 på det samhällsvetenskapliga programmet. Samtliga elever har besvarat kunskapstest skriftligt. En innehållsanalys med utgångspunkt från kompetenser och kunskapsnivåer har sedan utförts på elevernas skriftliga svar och resultatet visar att eleverna behärskar algoritmkompetens och att en del elever behärskar begreppskompetens. Resultatet visar också att de flesta av eleverna befinner sig på kunskapsnivå 2 och 3. Många elever saknar således en djupare förståelse för geometrin enligt analysen med kunskapsnivåer. Rekommendationen efter studien är att eleverna behöver mera undervisning om begreppens definitioner för att förbättra de andra kompetenserna såsom resonemangskompetens, modelleringskompetens och kommunikationskompetens.

The >1500 confirmed exoplanets span a wide range of planetary masses (~1 M_Earth – 20 M_Jupiter), radii (~0.3 R_Earth – 2 R_Jupiter), semi-major axes (~0.005 – 100 AU), orbital periods (~0.3 – 1 x 10⁵ days), and host star spectral types. The effects of a widely-varying parameter space on a planetary atmosphere's chemistry and dynamics can be determined through transiting exoplanet observations. An exoplanet's atmospheric signal, either in absorption or emission, is on the order of ~0.1% which is dwarfed by telescope-specific systematic error sources up to ~60%. This thesis explores some of the major sources of error and their removal from space- and ground-based observations, specifically Spitzer/IRAC single-object photometry, IRTF/SpeX and Palomar/TripleSpec low-resolution single-slit near-infrared spectroscopy, and Kuiper/Mont4k multi-object photometry. The errors include pointing-induced uncertainties, airmass variations, seeing-induced signal loss, telescope jitter, and system variability. They are treated with detector efficiency pixel-mapping, normalization routines, a principal component analysis, binning with the geometric mean in Fourier-space, characterization by a comparison star, repeatability, and stellar monitoring to get within a few times of the photon noise limit. As a result, these observations provide strong measurements of an exoplanet's dynamical day-to-night heat transport, constrain its CH₄ abundance, investigate emission mechanisms, and develop an observing strategy with smaller telescopes. The reduction methods presented here can also be applied to other existing and future platforms to identify and remove systematic errors. Until such sources of uncertainty are characterized with bright systems with large planetary signals for platforms such as the James Webb Space Telescope, for example, one cannot resolve smaller objects with more subtle spectral features, as expected of exo-Earths.

No description available.

Submitted by Priscila Nascimento (pnascimento@icict.fiocruz.br) on 2012-11-28T12:10:57Z No. of bitstreams: 1 ricardo-cristiano-de-souza-brum.pdf: 1743762 bytes, checksum: 0d2663a8b1457e7b609cb7288212d4da (MD5) / Made available in DSpace on 2012-11-28T12:10:57Z (GMT). No. of bitstreams: 1 ricardo-cristiano-de-souza-brum.pdf: 1743762 bytes, checksum: 0d2663a8b1457e7b609cb7288212d4da (MD5) Previous issue date: 2009 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / Nos últimos anos, as farmacopéias e principais agências regulatórias para produtos farmacêuticos e biofarmacêuticos exigem cada vez mais em suas monografias a aplicação do método para detecção de endotoxinas bacterianas pelo lisado de amebócitos de Limulus(LAL) no controle de pirogênio de produtos terminados parenterais. O objetivo do presente estudo foi padronizar e validar o ensaio de LAL para o biofármaco alfainterferona 2b humana recombinante, produzido em E. coli. Foram empregados os métodos Gel-Clot e Cinético-Cromogênico (semiquantitativo e quantitativo, respectivamente). Para o método Cinético-Cromogênico, a máxima diluição válida (MDV) foi calculada para cada apresentação com base na concentração do produto e a sensibilidade do teste (3 MUI, MDV: 1:3.888 e 10 MUI, MVD: 1:12.962). Diluições seriadas abaixo da MDV foram avaliadas emtriplicata para a verificação dos interferentes, sendo eleitas as diluições de 1:80 e1:100 que exibiram a melhor recuperação no controle positivo do produto. Para oensaio Gel-Clot na apresentação de 3 MUI (MDV: 1:17) foi estipulada a diluição de 1:8para a validação dos testes de rotina. Durante a validação dos ensaios, foi utilizada uma curva-padrão de endotoxina nas concentrações de 0,005 – 50 EU/ml e avaliados o seucoeficiente de correlação (R) e o desvio-padrão relativo. Os critérios de desempenho do método cinético (linearidade, especificidade, exatidão, repetibilidade, reprodutibilidade) foram atendidos de acordo com os parâmetros farmacopéicos e regulatórios (ANVISA e FDA), garantindo desta forma a robustez necessária para que o método de LAL possa ser incluído nos ensaios de rotina do Laboratório de Controle de Qualidade. / In recent years, the Pharmacopean, technical reports and international guides for pharmaceuticals products requires each time more intheir monographies the application of Limulus Ambocytes Lysateendotoxins assay (LAL) for release and pyrogen control in parenteral finished products. The objective of thisstudy was the standardization and validation of the LAL test for the human recombinant biopharmaceutical interferon alpha 2b, produced in E. coli, were used Gel-Clot and Chromogenics Kinetic methods (semi-quantitative and quantitative). In the case of Chromogenics method test, the maximum valid dilution (MDV) was calculated for each presentation based on the concentration of product (3 MUI, MDV: 1:3,888 and 10 MUI, MVD: 1:12,962), serial dilutions under the MDV (1:80) were evaluated in triplicate to detect interferences. For the gel-clot test for the 3 MUI presentation (MDV: 1:17) 1:8 dilution was setfor interferences detection test. For tests’ validation, several dilutions were performedusing standard endotoxin concentrations in 0,005 to 50 EU / ml to confirm the criteria for the methods performance (linearity, specificity, accuracy, reply, reproducibility). The results of validation showed that all pharmacopeia and regulatory parameters (ANVISA) studied, are compatible with the MDV used for each studied presentation of the human recombinant biopharmaceuticals interferon alpha 2b and may be used in quality control.

Sverige har under flera år fått svaga resultat i matematik i flera olika internationella undersökningar. Under min VFU-erfarenhet på ett gymnasium var matematik 2b en stor utmaning där cirka 83% av alla elever som skrev nationella provet år 2019 fick betyget F. Extra anpassningar i form av ett anpassat läromedel för dessa elever ansågs vara nödvändig och ett nytt utbildningsmaterial togs fram av mig. Syftet med arbetet är att skapa ett utbildningsmaterial för matematik 2b för att eleverna ska klara nationella provet. För att uppnå syftet har gamla nationella prov analyserats och ett utbildningsmaterial har tagits fram som grundar sig på områden som kommit flest gånger på dessa nationella prov. Vidare syftar rapporten till att följa upp eleverna som använt utbildningsmaterialet. Uppföljningen sker genom att utvärdera dessa elevers motivation och självförtroende med hjälp av intervjuer samt att deras resultat på nationella prov bedöms. Motivation är en viktig faktor i matematikundervisning och kan delas in i inre och yttre motivation. Inre motivation handlar om egen drivkraft medan yttre motivation handlar om att bli belönad av en annan person och motiveras genom detta. En studie gjord i USA visar att motivation är viktigare än intelligens för att lyckas inom matematik. Det finns även starka samband mellan självförtroende och betyg inom matematik. Det utvecklade utbildningsmaterialet prövades på 15 elever som tidigare fått ett F i kursen under en 2 veckorsperiod på en sommarlovsskola. Sedan utvärderades den genom att eleverna fick uppskatta hur materialet påverkat deras motivation och självförtroende. Denna uppskattning gjordes genom kvalitativa intervjuer via google meet. Eleverna skrev även ett nationellt prov som rättades. Åtta av de femton elever som deltog i sommarlovsskolan fick ett godkänt betyg på nationella provet. Eleverna tyckte även att utbildningsmaterialet hade en positiv påverkan på deras självförtroende och motivation. Det är inte säkert hur stor del av denna positiva påverkan utbildningsmaterialet haft. Andra saker som kan ha påverkat elevernas motivation och resultat är att sommarlovsskolan bestod av en mindre elevgrupp och att det var en ny lärare som undervisade dem. / Sweden has during many years received weak results in mathematics in different international surveys. During my placement experience at a high school, I noticed that mathematics 2b was a major challenge for the high school, where approximately 83% of all students who wrote the national exam received an F in 2019. The high school considered that extra adjustments in the form of adapted teaching materials were necessary for the students with an F. Therefore I created a teaching material for those students. The purpose was to create a teaching material for mathematics 2b to enable the students to pass the national exam. The teaching material was based on previous national exams and the types of questions that had occurred most often. Motivation is an important factor in mathematics teaching. Motivation can be divided into intrinsic and external motivation. Intrinsic motivation is about self-motivation, while external motivation is about being rewarded by another person and getting motivated by this. A study conducted in the United States shows that motivation is more important than intelligence to succeed in mathematics. There is also a strong connection between self-confidence and grades in mathematics. The educational material was tested on 15 students who had received an F in the course during two weeks in the form of a summer school. The educational material was evaluated by feedback from the students based on qualitative interviews via Google meet focusing on how the material affected their motivation and self-confidence. The students also wrote a national test that was corrected. Eight of the fifteen students who attended the summer school and used the teaching material received a passing grade on the national exam. In addition to this, the students also made it clear that the teaching material had a positive impact on their self-confidence and motivation.

El carcinoma medular de tiroides (CMT) es un tipo de neoplasia maligna infrecuente, con alto índice metastásico. Se presenta como un solo nódulo en más del 70% de los casos, y los principales órganos de metástasis a distancia son el hígado, el pulmón y el hueso. La metástasis en mama es rara, debido a que dentro de los tumores mamarios, solo entre el 0.2-1.3% son secundarios. El CMT se relaciona íntimamente con la neoplasia endocrina múltiple subtipo 2B (NEM2B), la cual es un desorden autosómico dominante caracterizado por la presencia de CMT y feocromocitoma en ausencia de hiperparatiroidismo. Rara vez, en el contexto de un NEM2B ocurre una metástasis de CMT en la mama, motivo por el cual se está presentando este caso

Epidemiology studies have established a strong link between chronic arsenic exposure and lung cancer. Currently, contribution of perturbed energy metabolism to carcinogenesis is an intensive area of research. In several human cell culture models (primary, immortal, malignant), we observed that non-cytotoxic exposure to arsenite increased extracellular acidification rate. Lactate accumulation caused by extracellular acidification, could be inhibited by 2-deoxy-D-glucose, a non-metabolized glucose analog. This established that arsenite induces aerobic glycolysis (the Warburg effect), a metabolic shift frequently observed in the acquisition of malignancy. Our studies in BEAS-2B, a non-malignant pulmonary epithelial cell line, found that the metabolic perturbation began early in the course of malignant transformation by arsenite (6 weeks). Correlated with the surge of glycolysis, we found elevated levels of HIF-1A and loss of E-Cadherin during chronic arsenite exposure. Our evidence suggests that this metabolic shift is sustained by HIF-1A (hypoxia-inducible factor 1A). We found that arsenite-exposed BEAS-2B accumulated HIF-1A protein, and underwent transcriptional up-regulation of HIF-1A-target genes. Overexpression of HIF-1A increases glycolysis 15% (vs. control), confirming that HIF-1A can modulate glycolysis in BEAS-2B. Coincident with induction of glycolysis, we observed a decrease in E-cadherin expression, indicating loss of epithelial identity. HIF-1A stable knockdown in BEAS-2B abrogated the arsenite induction of glycolysis, and indicated suppression in colony formation. These findings suggest that the hypoxia-mimetic effect of arsenite plays an important role in arsenite-induced malignant transformation. The significance of this study is that arsenite-induced alteration of energy metabolism represents the type of fundamental perturbation that could extend to many diverse effects caused by arsenic.