Fequency distribution of HLA DQ2 and DQ8 in celiac patients and first-degree relatives in Recife, northeastern Brazil

AIMS: The aim of this study was to evaluate the frequencies of the HLA genotypes DQ2 and DQ8 and the alleles A1*05, A1*0201, B1*0201 and B1*0302 in individuals with celiac disease in Recife, northeastern Brazil. METHODS: HLA DQ2 and DQ8 genotyping was performed for 73 individuals with celiac disease and 126 first-degree relatives with negative transglutaminase serology. The alleles DQA1*05, DQA1*0201, DQB1*02 and DQB1*0302 were identified by sequencing using specific primers and the EU-DQ kit from the Eurospital Laboratory, Trieste, Italy and double-checked by the All Set SPP kit (Dynal). RESULTS: Among the 73 cases, 50 (68.5%) had the genotype DQ2, 13 (17.8%) had DQ8, 5 (6.8%) had DQ2 and DQ8, and 5 did not have any of these genotypes. Among the 5 negative individuals, four had the B1*02 allele and one did not have any of the alleles studied. B1*02 was the most frequent allele in both groups (94% in the patients and 89% in the control relatives). CONCLUSIONS: In this study, celiac disease was associated with the genotypes DQ2 and DQ8. DQ2 predominated, but the distribution of the frequencies was different from what has been found in European populations and was closer to what has been found in the Americas. The high frequencies of the HLA genotypes DQ2 and DQ8 that were found in first-degree relatives would make it difficult to use these HLA genotypes for routine diagnosis of celiac disease in this group

Tempo ótimo entre manutenções preventivas para sistemas sujeitos a mais de um tipo de evento aleatório Optimal maintenance time for repairable systems in more than one type of failure

Um sistema reparável opera sob uma política de manutenção que especifica reparos preventivos em tempos pré-determinados e reparos mínimos quando ocorre uma falha. O processo de Poisson não-homogêneo é um modelo adequado para as falhas aleatórias que são tratadas por reparo mínimo. Assumindo um único tipo de falha e uma forma paramétrica para a função de intensidade deste processo, pode-se encontrar uma política ótima de manutenção preventiva que minimiza o custo médio por unidade de tempo. Este artigo foi motivado por uma situação envolvendo chaves seccionadoras de uma empresa de energia elétrica. Neste sistema existem dois tipos diferentes de eventos aleatórios, caracterizados por distintas causas de falhas. Uma política ótima de manutenção preventiva é obtida estendendo-se os resultados da situação envolvendo um único evento aleatório.A repairable system operates under a maintenance strategy that calls for complete preventive repair actions at pre-scheduled times and minimal repair actions whenever a failure occurs. Under minimal repair, failures are modeled according to a non-homogeneous Poisson process. When the intensity function is assumed to grow proportional to a power of time, this process is called the Power Law Process. The motivation for this paper was a maintenance data set related to power switch disconnectors. Two different types of failures could be observed for these systems according to their causes. The major differences between these types of failures are their costs. Assuming that the system will be in operation for an infinite time, we found the expected cost per unit of time for each preventive maintenance policy and hence obtained the optimal strategy as a function of the intensity function of the process. Large sample procedures to estimate the optimal maintenance check points for the Power Law Process are also discussed. The results are applied in the power switch disconnector data set

Seminário de Dissertação (2024)

Página da disciplina de Seminário de Dissertação (MPPP, UFPE, 2022) Lista de participantes == https://docs.google.com/spreadsheets/d/1mrULe1y04yPxHUBaF50jhaM1OY8QYJ3zva4N4yvm198/edit#gid=