Made available in DSpace on 2014-06-11T19:31:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-01Bitstream added on 2014-06-13T19:20:52Z : No. of bitstreams: 1 silva_mazm_dr_botfca.pdf: 771042 bytes, checksum: 7e34b884a402b5775a41c300fce626a8 (MD5) / Em muitas situações práticas em Energia na Agricultura pode-se utilizar modelos de regressão linear simples com o objetivo de compreender determinados fenômenos de interesse. No entanto, apesar de sua aparente simplicidade, esses modelos possuem certas pressuposições que devem ser observadas pelo pesquisador, como por exemplo, a normalidade dos erros, cuja violação traz sérios problemas com relação à qualidade dos estimadores de mínimos quadrados obtidos, podendo comprometer as conclusões do estudo. Desse modo, os modelos de regressão L1 , que tem como base a minimização da soma dos desvios absolutos, surgem como uma alternativa viável, pois fornecem estimadores robustos com relação à normalidade. Neste estudo, inicialmente, foram feitas comparações empíricas (simulação de Monte Carlo) entre os estimadores de mínimos quadrados e mínimos desvios absolutos de modelos de regressão linear simples com distribuição Gama padronizada, considerando a variação do parâmetro de escala entre 0,2 e 2,2 com incremento de 0,4 e o parâmetro de forma variando de 0,25 a 9,75 com incremento de 0,5. Foram, também, considerados os tamanhos de amostra variando de 20 a 100 com incremento de 20, com 1000 replicações. Nestas comparações, observou-se que: a razão e a diferença de erros quadráticos médios além de poderem ser usados com critérios para comparação da qualidade de estimadores, não diferindo entre si, produzem resultados diferentes do critério usual da variância residual; o parâmetro (l) de escala do modelo Gama de probabilidade é responsável por diferenciar a qualidade dos estimadores: l£1 o estimador de mínimos quadrados produz menor erro quadrático médio, caso contrário, o melhor estimador é o de mínimos desvios absolutos. Posteriormente, como aplicação prática desta metodologia, foram ajustados modelos... . / Linear regression models are widely used to understand many phenomena in agriculture. In the order hand, although apparently simple, these models have some assumptions that must be considered, like non-normal error. The violations of this assumption may mislead the conclusions of the results of the research. L1 regression models, which are based in the least absolute error, are very attractive as an alternative technique, since they have robust estimators with respected to normality. In this study, firstly, empirical comparisons was done (Monte Carlo simulation) between the least square estimator and the least absolute error (L1 regression) of the linear regression model with p.d.f. standard gamma distribution. The gamma parameters used in the simulations were: scale parameter varied from 0,2 to 2,2 by 0,4 and shape parameter varied from 0,25 to 9,75 by 0,5. The sampling size varied from 20 to 100 by 20, with 1.000 replications. In this comparisons, we see that the ratio and the difference between mean square error can be use to compare the quality estimators instead the residual variance estimated from the model. The shaper parameter of the Gamma model is responsible to choice between the two criteria, i.e., least square and least absolute error methods: When the shaper parameter is greater than 1,0 we choice the least absolute error methods, in the other hand, we choice the least square method. Further linear regression models were fitted using the two techniques, least square and the least absolute error, to the data of humidity in Zea mays L. in time, for several cultivars and crops. It was shown that, in majority cases, the L1 regression had estimators with mean squared error smaller than the least square estimator.

Submitted by Heitor Rapela Medeiros (heitor.rapela@ufpe.br) on 2015-03-04T14:26:35Z No. of bitstreams: 2 biblioteca - claudia.pdf: 1718092 bytes, checksum: b722f27aa93ca90535409b6846ae7dda (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-04T14:26:35Z (GMT). No. of bitstreams: 2 biblioteca - claudia.pdf: 1718092 bytes, checksum: b722f27aa93ca90535409b6846ae7dda (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012-09-04 / O Papiloma Vírus Humano - HPV é um dos mais importantes vírus relacionados com a carcinogênese, já sendo conhecido seu papel na gênese do carcinoma cervical uterino. A maioria dos casos de câncer gástrico está relacionada a um agente infeccioso: Helicobacter Pylori. Outros agentes infecciosos como os vírus Epsten-Barr e HPV são relatados associados ao câncer gástrico. Objetivo: Este estudo visa investigar a associação do HPV em pacientes com câncer gástrico e comparar a um grupo controle sem neoplasia. Método: Foram analisadas 40 amostras parafinadas provenientes de portadores de câncer gástrico e 40 amostras de pacientes do grupo controle submetidos à endoscopia e biópsia de mucosa gástrica normal e sangue periférico, no período de 2008 a 2009. O material coletado foi examinado por Reação de Cadeia de Polimerase - PCR para gene da região L1-HPV. O DNA extraído foi amplificado em dois sistemas de reação utilizando-se dois pares de primers: MY09/MY11 (fragmento de 450pb) e GP+5/GP+6 (fragmento de 150pb). Foi utilizada água Mili-Q como controle negativo da reação, sendo o controle positivo uma mistura de 01μL de sangue humano acrescido de 0,25μL de plasmídeo p BR322(HPV16). Resultados: Foram identificados em quatro pacientes com CG a presença de HPV associado à mucosa tumoral, nos pacientes sem neoplasia gástrica foram identificados 10 casos de HPV associado à mucosa gástrica. Conclusão: No presente estudo não encontramos indícios de associação significativa do HPV ao câncer gástrico (p=0,077).

Obesity is a growing concern in the world today. As we ponder about the many causes of this global epidemic, we are driven to look at our food and the environmental toxicants that may contribute to obesity. Deltamethrin, being a common synthetic pyrethroid used in agriculture for pest control, is the primary insecticide this study explores to connect with obesity in 3T3-L1 adipocytes. To investigate the relationship between deltamethrin and adipogenesis, various concentrations were tested, 1nM, 10nM, 100nM, 1μM, and 10μM. The result indicated that higher concentration of deltamethrin had a direct impact on fat accumulation. These experiment results indicate that deltamethrin may potentiate adipogenesis in this model. Further in vivo studies will be needed to validate these findings and confirm the effects of deltamethrin on obesity.

Clinical trials are currently exploring the combinations of P ARP inhibitors and immunotherapies in the treatment of ovarian cancer, but their effects on the ovarian tumour microenvironment (TME) remain unclear. Here, we investigate how olaparib, PD-L1 monoclonal antibodies and their combination can influence TME composition and survival of tumour-bearing mice. We further explored how BRCA mutations can influence the response to therapy. Olaparib and combination therapies similarly improved the median survival of Brca1- and Brca2-deficient tumour-bearing mice. Anti-PD-L1 monotherapy improved the survival of mice with Brca1-null tumours, but not Brca2-null tumours. A detailed analysis of the TME revealed that the olaparib monotherapy resulted in a large number of immunosuppressive and immunomodulatory effects in the more inflamed Brca1-deficient TME but not Brca2-deficient tumours. Anti-PD-L1 treatment was mostly immunosuppressive, resulting in a systemic reduction of cytokines and a compensatory increase of PD-L1. The results of the combination therapy generally resembled the effects of one or both of the monotherapies, along with unique changes observed in certain immune populations. In-silico analysis of RNA-seq also revealed numerous differences between Brca-mutated tumour models. In summary, these findings shed light on the influence of novel therapeutics and BRCA mutations on the ovarian TME.

Yes / African trypanosomes, except Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, which cause human African trypanosomiasis, are lysed by the human serum protein apolipoprotein L1 (ApoL1). These two subspecies can resist human ApoL1 because they express the serum resistance proteins T. b. gambiense glycoprotein (TgsGP) and serum resistance-associated protein (SRA), respectively. Whereas in T. b. rhodesiense, SRA is necessary and sufficient to inhibit ApoL1, in T. b. gambiense, TgsGP cannot protect against high ApoL1 uptake, so different additional mechanisms contribute to limit this uptake. Here we report a complex interplay between trypanosomes and an ApoL1 variant, revealing important insights into innate human immunity against these parasites. Using whole-genome sequencing, we characterized an atypical T. b. gambiense infection in a patient in Ghana. We show that the infecting trypanosome has diverged from the classical T. b. gambiense strains and lacks the TgsGP defense mechanism against human serum. By sequencing the ApoL1 gene of the patient and subsequent in vitro mutagenesis experiments, we demonstrate that a homozygous missense substitution (N264K) in the membrane-addressing domain of this ApoL1 variant knocks down the trypanolytic activity, allowing the trypanosome to avoid ApoL1-mediated immunity. IMPORTANCE. Most African trypanosomes are lysed by the ApoL1 protein in human serum. Only the subspecies Trypanosoma b. gambiense and T. b. rhodesiense can resist lysis by ApoL1 because they express specific serum resistance proteins. We here report a complex interplay between trypanosomes and an ApoL1 variant characterized by a homozygous missense substitution (N264K) in the domain that we hypothesize interacts with the endolysosomal membranes of trypanosomes. The N264K substitution knocks down the lytic activity of ApoL1 against T. b. gambiense strains lacking the TgsGP defense mechanism and against T. b. rhodesiense if N264K is accompanied by additional substitutions in the SRA-interacting domain. Our data suggest that populations with high frequencies of the homozygous N264K ApoL1 variant may be at increased risk of contracting human African trypanosomiasis. / This work, including the efforts of Stijn Deborggraeve, was funded by Research Foundation Flanders (1501413N). This work, including the efforts of Bart Cuypers, was funded by Research Foundation Flanders (11O1614N). This work, including the efforts of Jean-Claude Dujardin and Etienne Pays, was funded by Interuniversity Attraction Poles Program of Belgian Science Policy (P7/41). This work, including the efforts of Jean-Claude Dujardin, was funded by Flemish Ministry of Sciences (SOFI-B SINGLE). This work, including the efforts of Etienne Pays, was funded by EC | European Research Council (ERC) (APOLs 669007).

No description available.

No description available.

White adipose tissue (WAT) stores triglycerides and is crucial to maintaining the body's energy balance. Attributed to its plasticity, WAT can undergo dynamic remodeling in response to chronic energy excess. As obesity increases, alterations in the quantity and function of progenitor and immune cells result in fibrosis and inflammation in the WAT. Hence, metabolic dysfunction becomes more severe. In a recent study, HFD feeding significantly increased the gene expressions of bone morphogenetic protein 2 (BMP2), acidic fibroblast growth factor (FGF1), and basic fibroblast growth factor (FGF2) in macrophages. It was found in a fibrotic environment that the factors stimulated the growth of progenitor cells and the expression of fibrotic genes but suppressed adipogenesis. We looked at how these ligands affect fat metabolism, including adipogenesis, fibrosis, and thermogenesis. We also found out how these ligands affect the way progenitor cells change. By conducting proliferation and differentiation experiments on the 3T3-L1 cell model in vitro with these ligands supplemented at different phases, we demonstrated these ligands' influence 3T3-L1 preadipocytes and adipocytes genotype and phenotype. Based on this research, it was found that BMP2 stimulates adipogenesis by making cells multiply and differentiate. FGF1 exhibits different phasic influences on adipogenesis. FGF1 suppresses the preadipocyte differentiation phase but promotes cell proliferation, which increases the cell confluence speed and might lead to earlier differentiation of adipocytes. FGF2 added in the proliferation phase did not have much effect on adipogenesis. FGF2 might promote preadipocyte commitment during the adipocyte-genesis stage of differentiation phase but the comprehensive effect remains ambiguous.

Das Kolorektale Karzinom (KRK) ist eines der häufigsten malignen Erkrankungen, an der in Deutschland jährlich 26000 Menschen versterben. Auf der Suche nach einem neuen Biomarker für dieses Malignom wurde in dieser Arbeit L1-CAM, ein neuronales Zell-Adhäsionsmolekül, untersucht. Es ist, exprimiert an der Zelloberfläche, assoziiert mit einem signifikant schlechteren Outcome bedingt durch eine raschere lokale Tumorausbreitung und Metastasierung. Es zeigte sich anhand der Untersuchung von 62 Tumorpräparate und 39 präoperativ gewonnenen Seren, dass L1-CAM sowohl immunhistologisch nachgewiesen auf der Tumoroberfläche als auch mittels ELISA bestimmt im Serum der Patienten nachweisbar ist. Patienten mit L1-CAM positiven Tumoren waren im Mittel deutlich jünger als Patienten ohne L1-CAM Expression (60 vs. 69 Jahre). Zudem zeigte sich, dass Patienten mit schwach L1-CAM positiven Tumoren im Mittel einen signifikant höheren BMI aufwiesen (Kruskal Wallis Test p=0,0354). Die L1-CAM Expression hatte in unserem Patientengut keinen signifikanten Einfluss auf die Tumorausbreitung, wenngleich wir eine häufigere Metastasierung in die Leber (44%) bei L1-CAM positiven Tumoren gegenüber Patienten ohne L1-CAM Expression im Tumor (29%) beobachteten. Gleiches gilt für die Infiltration der Perineuralscheiden durch Tumorzellen. Bei der Untersuchung der L1-CAM Serumkonzentrationen zeigte sich im Mittel kein signifikanter Unterschied zu einer gesunden Vergleichsgruppe, sodass L1-CAM als Serum-Tumormarker ungeeignet ist.

O papilomavirus humano (HPV) é o agente etiológico da infecção sexualmente transmissível mais comum na população mundial. A prevalência da infecção por HPV é estimada em 660 milhões de pessoas e mais de 50% das mulheres serão acometidas pela infecção ao menos uma vez na vida. O HPV é responsável por virtualmente todos os casos de câncer de colo de útero (99%), além de causar muitos outros tipos de câncer de mucosa. O câncer cervical afeta aproximadamente 1.4 milhões de mulheres e 500 mil novos casos surgem anualmente, resultando em 250 mil mortes por ano. Os maiores índices de incidência são observados na América Latina e na África. Duas vacinas contra o HPV são comercializadas desde 2006 por empresas estrangeiras. Entretanto, o custo mínimo da vacinação é superior a 600 reais. Este preço torna sua incorporação pelo sistema de saúde um processo economicamente inviável. Dessa forma, devem ser buscadas alternativas para a produção de uma vacina eficaz, de qualidade e de baixo custo no Brasil. A proteína L1, principal proteína do capsídeo do HPV, tem a propriedade de se auto agregar em partículas semelhantes às virais (VLPs), que são o principal componente das vacinas atuais e possuem muita semelhança com os vírions nativos, introduzindo inclusive, uma imunização predominantemente tipo-específica. Este projeto se propôs a construir e avaliar vetores de expressão visando à produção em larga escala da proteína L1 do HPV 16, o tipo de HPV de maior risco e incidência na população mundial. Foram construídos cinco plasmídeos para Pichia pastoris, uma das principais plataformas industriais de expressão. Eles se diferenciam pelos marcadores de seleção e pelas sequências de manutenção do vetor, mas têm exatamente o mesmo objetivo: gerar sistemas que possuam múltiplas cópias do gene da L1 e que não necessitem da utilização de antibióticos. Essa estratégia foi escolhida porque a produtividade de muitas das proteínas heterólogas tem grande dependência da dosagem gênica e porque o uso de antibióticos encarece muito o custo da produção. Na primeira etapa do projeto foi avaliado um sistema de expressão epissomal auxotrófico, mas ele não se manteve estável ao longo de 60 gerações. Na segunda parte, dois vetores de integração ao sítio do DNA ribossomal foram testados. O sistema mais estável e produtivo foi caracterizado quanto ao número de cópias integradas ao genoma da P. pastoris e ao nível de expressão. O sistema é capaz de produzir clones com mais de 30 cópias do gene da L1 e dois clones expressaram cerca de 20 a 30 miligramas/litro de L1. Adicionalmente outros dois vetores integrativos que utilizam sequências teloméricas para integração foram construídos. Ainda são necessários estudos conjuntos de fermentação em larga escala e purificação da proteína para verificar a viabilidade do sistema / The human papillomavirus (HPV) is the etiologic agent of the sexually transmitted infection most common worldwide. The prevalence of HPV infection is estimated at 660 million people and over 50% of women will be affected by the infection at least once in their lifetime. HPV is responsible for virtually all cervical cancers cases (99%), and causes many other types of mucosal cancer. Cervical cancer affects approximately 1.4 million women, and 500.000 new cases occur annually, resulting in 250.000 deaths per year. The highest incidence rates are seen in Latin America and Africa. Two HPV vaccines are marketed since 2006 by foreign companies. However, the minimum cost of vaccination is higher than 360 dollar. This price makes its incorporation by the Brazilian Health System economically unfeasible. Thus, alternatives must be found to produce an effective vaccine, with low cost and high-quality in Brazil. The L1 protein, the major capsid protein of HPV, has the ability to self aggregate into virus-like particles (VLPs) which are the main component of current vaccines. The VLPs are very similar to the native virions and can introduce an immunization predominantly type-specific. This project aimed to construct and evaluate expression vectors to produce, at large scale, the L1 protein of HPV 16, which is the HPV type at greater risk and incidence in the world. Five plasmids were constructed for Pichia pastoris, one of the major industrial expression platforms. They differ in the selection markers and the vector maintenance sequences, but they have exactly the same goal: to create systems with multiple copies of the L1 gene and that don\'t require the use of antibiotics. This strategy was chosen because the productivity of many heterologous proteins have heavy dependence on gene dosage and because the use of antibiotics is extremely expensive for its production. In the first stage of the project, it was rated an episomal auxotrophic expression system, but it was unstable after a period of 60 generations. In the second part, two vectors for integration in the ribosomal DNA locus were tested. The most stable and productive system was featured on the number of copies integrated into the P. pastoris genome and on the expression level. It was proved that the system is able to produce clones with more than 30 copies of the L1 gene and two clones expressed approximately 20-30 milligrams/liter of L1. Additionally, two other integrative vectors for integration in telomeric sequences were constructed for future testing. More studies on large-scale fermentation and protein purification will be necessary to determine the feasibility of the system.