Some new approaches for modeling the incubation period of HIV/AIDS epidemic

The time duration between HIV seroconversion to AIDS known as Incubation period is very long and highly variable across groups. Several models for incubation period distribution were studied by many author. In this paper we propose new approaches to model the distribution of the incubation period of HIV/AIDS epidemic using the stages of the disease, the threshold level and cumulative invasion of the immune system. But each model has its own limitations

Processamento e tenacificação de compósitos de fase metálica e carbonetos duais

Mestrado em Ciência e Engenharia dos MateriaisThis work on the processing and study of the indentation fracture composites of dual-metallic phase of Al-Si and dual carbide phase of B4C and SiC uses the reactive melt infiltration method to prepare nearly fully dense samples. Batches of single and twice smelted Al-Si alloys of hypereutectic composition were produced by mixing aluminium and silicon powders in the proportion of 25 wt% and 35 wt% Si and melting at 1000 ºC for 60 minutes in argon atmosphere. Boron carbide powder of 10 μm average particle size, containing free carbon, mostly graphite, was used to prepare nominally 50% dense cylindrical pellets of 7.5 mm of height by uniaxial pressing followed by cold isostatic pressing. B4C preforms become spontaneously infiltrated by the reactive melt of the Al-Si alloy at 1200 °C and 1300 °C in 5 minutes using a resistive heated graphite furnace with inert argon atmosphere. Defects related to infiltration are described in the study, the conditions and contamination in oxygen of the alloy and furnace atmosphere that could have caused partial or absence of infiltration of the B4C preforms are discussed. A set of fully infiltrated samples of the composites was obtained representing different Si proportions in the infiltrate and two temperatures where infiltration became feasible within the range of experimental conditions of this study. Polished longitudinal sections of the pellets were further investigated by using quantitative XRD methods with standards for the volume fractions of the main crystalline phases, Al, Si, B4C and SiC and scanning electron microscopy with standard-less energy dispersive analysis SEM/EDS for the element distribution in the phases. The reaction path accounting for changes in the volume fraction of the phases from top, the melt infiltration face, to the bottom areas were represented in isothermal section of the Al-Si-B4C phase diagram. The corresponding representations of the average elemental composition of the composites in the Al-Si-C and Al-Si-B-C phase diagrams expose a large content of Al, mostly Al metal in the composites which explains the comparatively low values of hardness. An indentation size effect of the Vickers hardness is observed for indentation loads of 9.8 N, 98 N and 294 N, the hardness of the composites determined at 98 N being correlated to the Si concentration of the Al-Si infiltrate. In spite of the scatter of indentation fracture toughness determined at 98 N, the high values toughness of the composites in this study are correlated to the comparatively low values of hardness in the same way as recently published in a similar study of reactive melt infiltration of B4C composites with Al-Si alloys of high Si content. The way the toughening mechanism may depend on the distribution of the brittle phases and ductile Al and interphase de-bonding is further discussed.Este trabalho incide sobre o processamento e estudo da tenacificação dos compósitos de fase metálica dual e dupla fase de carbonetos, com B4C e SiC, e utiliza a técnica infiltração reactiva da liga fundida para preparar amostras quase totalmente densas dos compósitos. Lotes de ligas hipereutécticas de Al-Si fundidas uma e duas vezes foram produzidas a partir de pós de alumínio e de silício, na proporção de 25% em peso e 35% em peso de Si e tendo-se feito a fusão a 1000 ºC durante 60 minutos em atmosfera de argon. Utilizou-se um pó de carboneto de boro de 10 um de tamanho médio de partícula, com carbono livre, principalmente grafite, para preparar provetes cilíndricos, de 7,5 mm de altura e densidade relativa nominal de 50%, por prensagem uniaxial seguida de prensagem isostática a frio. O fundido reactivo da liga de Al-Si infiltra espontaneamente as preformas de B4C às temperaturas de 1200 ºC e 1300 ºC, em 5 minutos, tendo-se utilizando um forno de resistência de grafite com uma atmosfera inerte de árgon. No estudo descrevem-se os defeitos relacionados com a infiltração e são discutidas as condições experimentais e da contaminação em oxigénio da atmosfera do forno e da liga que poderiam ter causado a infiltração parcial ou a ausência de infiltração das preformas de B4C. Obteve-se um conjunto de amostras dos compósitos totalmente infiltradas representando diferentes proporções de Si no infiltrado e as duas temperaturas em que a infiltração se tornou exequível dentro do intervalo de condições experimentais deste estudo. Seções polidas longitudinais dos provetes foram investigadas através de métodos quantitativos de DRX com padrões para a determinação das fracções volúmicas das principais fases cristalinas, Al, Si, B4C e SiC e a microscopia electrónica de varrimento com análise de energia dispersiva sem padrão SEM/EDS para distribuição dos elementos na composição das fases. Os percursos de reacção no interior dos compósitos tendo em conta as alterações na fracção volúmica das fases entre a face superior, a face infiltração do fundido, e a face inferior dos provetes fundo foram representados na secção isotérmica do diagrama de fases Al-Si-B4C. As correspondentes representações da composição química elementar média dos compósitos nos diagramas de fases de Al-Si-C e Al-Si-B-C põem em evidência o elevado teor de Al nos compósitos, principalmente Al metálico, o que explica os valores de dureza comparativamente baixos. Um efeito do tamanho de indentação é observado na dureza Vickers para as cargas de indentação de 9,8 N, 98 N e 294 N, estando a dureza aos 98 N correlacionada com a concentração de Si no infiltrado de Al-Si. Apesar da dispersão de valores da tenacidade à fractura de indentação determinada a 98 N, a valores altos da tenacidade dos compósitos deste estudo estão correlacionados com os valores relativamente baixos de dureza da mesma maneira como se encontrou nos resultados recentemente publicados de um estudo semelhante de infiltração reactiva de compósitos B4C com ligas Al-Si com teor de Si mais elevado. Procurou-se discutir ainda a forma como o mecanismo de tenacificação poderá depender das distribuições das fases frágeis e da fase dúctil de Al e bem como do desligamento do Al nas interfaces com as fases cerâmicas

Predicting hospital costs for patients receiving renal replacement therapy to inform an economic evaluation.

OBJECTIVE: To develop a model to predict annual hospital costs for patients with established renal failure, taking into account the effect of patient and treatment characteristics of potential relevance for conducting an economic evaluation, such as age, comorbidities and time on treatment. The analysis focuses on factors leading to variations in inpatient and outpatient costs and excludes fixed costs associated with dialysis, transplant surgery and high cost drugs. METHODS: Annual costs of inpatient and outpatient hospital episodes for patients starting renal replacement therapy in England were obtained from a large retrospective dataset. Multiple imputation was performed to estimate missing costs due to administrative censoring. Two-part models were developed using logistic regression to first predict the probability of incurring any hospital costs before fitting generalised linear models to estimate the level of cost in patients with positive costs. Separate models were developed to predict inpatient and outpatient costs for each treatment modality. RESULTS: Data on hospital costs were available for 15,869 incident dialysis patients and 4511 incident transplant patients. The two-part models showed a decreasing trend in costs with increasing number of years on treatment, with the exception of dialysis outpatient costs. Age did not have a consistent effect on hospital costs; however, comorbidities such as diabetes and peripheral vascular disease were strong predictors of higher hospital costs in all four models. CONCLUSION: Analysis of patient-level data can result in a deeper understanding of factors associated with variations in hospital costs and can improve the accuracy with which costs are estimated in the context of economic evaluations.<br/

Responsabilidade civil devido a causa indeterminada da lei iraniana e británica

One of the most important and most significant issues in civil responsibility is the issue of "indeterminate " and” causation” . The term has created a combination of the two words " indeterminate" and " causation ". And in the definition of the “indeterminate causation” we can say that the uncertain factor in the causation of loss among likely persons. When knowledge of the occurrence of a loss by an agent is due to several factors of the loss, but it cannot be determined definitively and definitely, the discussion of indeterminate causation is raised. The lawyers, having emphasized the necessity of proving the relation between the causal link between a harmful act by a certain person and the entry of a loss to the loser, and the absence of such a relationship in the assumption of the indeterminate causation , considered the liability completely excluded. But after a while, the collective responsibility view of probable actors was posed, which is of solidarity type in French law and proportional to the type of liability in Common law in, and the aspect of the proof is of great importance.Uno de los temas más importantes y más significativos en la responsabilidad civil es el tema de "indeterminación" y "causalidad". El término ha creado una combinación de las dos palabras "indeterminado" y "causalidad". Y en la definición de "causalidad indeterminada" podemos decir que es el factor incierto en la causalidad de la pérdida entre las personas probables. Cuando el conocimiento de la ocurrencia de una pérdida por un agente se debe a varios factores de la pérdida, pero no puede determinarse de manera absoluta y definitiva, se plantea la discusión de la causalidad indeterminada. Los abogados, habiendo enfatizado la necesidad de probar la relación entre el nexo causal entre un acto dañino de cierta persona y el ingreso de una pérdida al perdedor, y la ausencia de tal relación en el supuesto de la causalidad indeterminada, considerado el pasivo completamente excluido. Pero después de un tiempo, se planteó la visión de responsabilidad colectiva de los actores probables, que es de tipo solidario en la ley francesa y proporcional al tipo de responsabilidad en ley comun en, y el aspecto de la prueba es de gran importancia.Um dos temas mais importantes e mais importantes da responsabilidade civil é o tema da "indeterminação" e "causalidade". El término ha creado una combinação das palabras "indeterminado" y "causalidad". Y en la definición de "causali-dad indeterminada" podemos decir que el factor incierto en la causalidad de la pérdida entre las personas probables. Cuando o conocimiento da ocorrência de uma perda por agente pode ser uma variável fatores da perda, não é um processo de decisão absoluta e definitiva, é um processo de discussão da causalidade indeterminada. Los abogados, habatendo enfatized the necesidad of probar la relación between the nexo causal between un acto dañino of cierta persona and the ingreso de una perdida al perdedor, y la au-sencia de tal relación en el supuesto de la causalidad indeterminada, considerado el pa -sivo completamente excluido. Perú despiu de un tiempo, se plerou la visión de responsabilidad colectiva de los actores probables, que es de solidario la la ley francesa y proporcional o tipo de responsabilidade na ley comun, y el aspecto de la prueba es de gran importancia

CIVIL LIABILITY OF THE INCONCLUSIVE CAUSALITY OF THE MEDICAL TEAM IN IRAN, INDIA AND BRITAIN

Abstract. Statement of Problem and Research Questions. In the legal system of Iran, India, and England (Common Law), the issue of Tort committed by the medical team happens when in reality, there is the knowledge of damage inflicted by several causes, however it is not clear which cause has caused the damage. In the Iranian law, there have been suggested several ways for determining the liability of damage compensation such as the implementation of the right of choice in the cases of tort, the sentence establishment of the jurists as a rule, drawing, Citation to judicial circumstantial presumption, Compensation from public funds, treasury, Execution and aggregation of two conflictingsentences, Risk theory, presumption of responsibility, and the application of great judge authority, and in the Penal Code of 2015, the liability is equal. In the Indian Law, in terms of tort law in civil liability, there have not been offered any specific sentences. However, in the section 43 of the Contractual Law of 1872 on compensation of the shared damages in which the share of the parties is not determined, they are equally responsible for damage compensation, but in case one of the parties is deceased, the other party will be responsible for the compensation

The global impact of COVID-19 on solid organ transplantation: two years into a pandemic

The coronavirus disease 2019 (COVID-19) pandemic has had a major global impact on solid organ transplantation (SOT). An estimated 16% global reduction in transplant activity occurred over the course of 2020, most markedly impacting kidney transplant and living donor programs, resulting in substantial knock-on effects for waitlisted patients. The increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection risk and excess deaths in transplant candidates has resulted in substantial effort to prioritize the safe restart and continuation of transplant programs over the second year of the pandemic, with transplant rates returning towards prepandemic levels. Over the past 2 y, COVID-19 mortality in SOT recipients has fallen from 20%–25% to 8%–10%, attributed to the increased and early availability of SARS-CoV-2 testing, adherence to nonpharmaceutical interventions, development of novel treatments, and vaccination. Despite these positive steps, transplant programs and SOT recipients continue to face challenges. Vaccine efficacy in SOT recipients is substantially lower than the general population and SOT recipients remain at an increased risk of adverse outcomes if they develop COVID-19. SOT recipients and transplant teams need to remain vigilant and ongoing adherence to nonpharmaceutical interventions appears essential. In this review, we summarize the global impact of COVID-19 on transplant activity, donor evaluation, and patient outcomes over the past 2 y, discuss the current strategies aimed at preventing and treating SARS-CoV-2 infection in SOT recipients, and based on lessons learnt from this pandemic, propose steps the transplant community could consider as preparation for future pandemics

Inequity in access to transplantation in the UK

Background and objectives Despite the presence of a universal health care system, it is unclear if there is intercenter variation in access to kidney transplantation in the United Kingdom. This study aims to assess whether equity exists in access to kidney transplantation in the United Kingdom after adjustment for patient-specific factors and center practice patterns. Design, setting, participants, & measurements In this prospective, observational cohort study including all 71 United Kingdom kidney centers, incident RRT patients recruited between November 2011 and March 2013 as part of the Access to Transplantation and Transplant Outcome Measures study were analyzed to assess preemptive listing (n=2676) and listing within 2 years of starting dialysis (n=1970) by center. Results Seven hundred and six participants (26%) were listed preemptively, whereas 585 (30%) were listed within 2 years of commencing dialysis. The interquartile range across centers was 6%–33% for preemptive listing and 25%–40% for listing after starting dialysis. Patient factors, including increasing age, most comorbidities, body mass index >35 kg/m2, and lower socioeconomic status, were associated with a lower likelihood of being listed and accounted for 89% and 97% of measured intercenter variation for preemptive listing and listing within 2 years of starting dialysis, respectively. Asian (odds ratio, 0.49; 95% confidence interval, 0.33 to 0.72) and Black (odds ratio, 0.43; 95% confidence interval, 0.26 to 0.71) participants were both associated with reduced access to preemptive listing; however Asian participants were associated with a higher likelihood of being listed after starting dialysis (odds ratio, 1.42; 95% confidence interval, 1.12 to 1.79). As for center factors, being registered at a transplanting center (odds ratio, 3.1; 95% confidence interval, 2.36 to 4.07) and a universal approach to discussing transplantation (odds ratio, 1.4; 95% confidence interval, 1.08 to 1.78) were associated with higher preemptive listing, whereas using a written protocol was associated negatively with listing within 2 years of starting dialysis (odds ratio, 0.7; 95% confidence interval, 0.58 to 0.9). Conclusions Patient case mix accounts for most of the intercenter variation seen in access to transplantation in the United Kingdom, with practice patterns also contributing some variation. Socioeconomic inequity exists despite having a universal health care system

Signaling pathways involved in LPS induced TNFalpha production in human adipocytes

<p>Abstract</p> <p>Background</p> <p>The development of obesity has been linked to an inflammatory process, and the role of adipose tissue in the secretion of pro-inflammatory molecules such as IL-6 or TNFalpha has now been largely confirmed. Although TNFalpha secretion by adipose cells is probably induced, most notably by TLR ligands, the activation and secretion pathways of this cytokine are not yet entirely understood. Moreover, given that macrophagic infiltration is a characteristic of obesity, it is difficult to clearly establish the level of involvement of the different cellular types present within the adipose tissue during inflammation.</p> <p>Methods</p> <p>Primary cultures of human adipocytes and human peripheral blood mononuclear cells were used. Cells were treated with a pathogen-associated molecular pattern: LPS, with and without several kinase inhibitors. Western blot for p38 MAP Kinase was performed on cell lysates. TNFalpha mRNA was detected in cells by RT-PCR and TNFalpha protein was detected in supernatants by ELISA assays.</p> <p>Results</p> <p>We show for the first time that the production of TNFalpha in mature human adipocytes is mainly dependent upon two pathways: NFkappaB and p38 MAP Kinase. Moreover, we demonstrate that the PI3Kinase pathway is clearly involved in the first step of the LPS-pathway. Lastly, we show that adipocytes are able to secrete a large amount of TNFalpha compared to macrophages.</p> <p>Conclusion</p> <p>This study clearly demonstrates that the LPS induced activation pathway is an integral part of the inflammatory process linked to obesity, and that adipocytes are responsible for most of the secreted TNFalpha in inflamed adipose tissue, through TLR4 activation.</p