A novel single-phase ZCS-PWM high-power-factor boost rectifier

This paper presents a novel single-phase high-power-factor (HPF) pulsewidth-modulated (PWM) boost rectifier featuring soft commutation of the active switches at zero current (ZC), It incorporates the most desirable properties of conventional PWM and soft-switching resonant techniques.The input current shaping is achieved with average current mode control and continuous inductor current mode.This new PWM converter provides ZC turn on and turn off of the active switches, and it is suitable for high-power applications employing insulated gate bipolar transistors (IGBT's),The principle of operation, the theoretical analysis, a design example, and experimental results from a laboratory prototype rated at 1600 W with 400-Vdc output voltage are presented. The measured efficiency and the power factor were 96.2% and 0.99%, respectively, with an input current total harmonic distortion (THD) equal to 3.94%, for an input voltage with THD equal to 3.8%, at rated load.

Novel zero-current-switching PWM converters

This paper presents a new family of pulsewidth-modulated (PWM) converters, featuring soft commutation of the semiconductors at zero current (ZC) in the transistors and zero voltage (ZV) in the rectifiers, Besides operating at constant frequency and with reduced commutation losses, these new converters have output characteristics similar to the hard-switching-PWM counterpart, which means that there is no circulating reactive energy that would cause large conduction losses, the new family of zero-current-switching (ZCS)-PWM converters is suitable for high-power applications using insulated gate bipolar transistors (IGBT's). The advantages of the new ZCS-PWM boast converter employing IGBT's, rated at 1.6 kW and operating at 20 kHz, are presented, This new ZCS operation can reduce the average total power dissipation in the semiconductors practically by half, when compared with the hard-switching method, This new ZCS-PWM boost converter is suitable for high-power applications using Ie;BT's in power-factor correction, the principle of operation, theoretical analysis, and experimental results of the new ZCS-PWM boost converter are provided in this paper to verify the performance of this new family of converters.

A novel HPF voltage source rectifier for variable speed refrigeration systems

A novel single-phase voltage source rectifier capable to achieve High-Power-Factor (HPF) for variable speed refrigeration system application, is proposed in this paper. The proposed system is composed by a single-phase high-power-factor boost rectifier, with two cells in interleave connection, operating in critical conduction mode, and employing a soft-switching technique, controlled by a Field Programmable Gate Array (FPGA), associated with a conventional three-phase IGBT bridge inverter (VSI - Voltage Source Inverter), controlled by a Digital Signal Processor (DSP). The soft-switching technique for the input stage is based on zero-current-switching (ZCS) cells. The rectifier's features include the reduction in the input current ripple, the reduction in the output voltage ripple, the use of low stress devices, low volume for the EMI input filter, high input power factor (PF), and low total harmonic distortion (THD) in the input current, in compliance with the EEC61000-3-2 standards. The digital controller for the output stage has been developed using a conventional voltage-frequency control (scalar V/f control), and a simplified stator oriented Vector control, in order to verify the feasibility and performance of the proposed digital controls for continuous temperature control applied at a refrigerator prototype.

Effect of fractional urea clearance on survival of hemodialysis patients in relation to gender

Many studies have demonstrated the relationship between dialysis dose and survival. Global mortality is similar among men and women; however, the influence of dialysis dose in the survival could be more intensive between women. Therefore, we conduct an observational study to evaluate the gender-related impact of single pool Kt/V (spKt/V) on the survival of patients submitted to hemodialysis in a university hospital. We found that survival was lower in groups with spKt/V smaller than 1.2 than in those with Kt/V between 1.2 and 1.4. Among female patients, spKt/V smaller than 1.2 had a more adverse effect in survival than among men with a comparable Kt/V. Otherwise, among women, the dialysis dose had an impact in survival even with Kt/V greater than 1.4. Thus, fractional urea clearance more heavily influenced the survival of females than males in hemodialysis patients.

Role of Peritubular Capillaries and Vascular Endothelial Growth Factor in Chronic Allograft Nephropathy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Considerações sobre o câncer localmente avançado de mama (CLAM) acrescidas de identificação dos receptores de estrogênios usando anticorpos monoclonais.

The effects of therapy in locally advanced breast cancer submitted to combined conventional telecobalt therapy plus chemotherapy with cyclophosphamide and 5-fluorouracil were studied in 49 patients. Associated to radical mastectomy in operable cases. Local tumor control was achieved in 86.7%. There were no local recurrences in those submitted to surgery but they reached 21.7% in inoperable patients who received only radiation therapy and chemotherapy. The median follow-up time for dead patients was 29.5 months and for living patients 79.3 months. The index of complete responses was 24.5% and the median disease free interval was 22.9 months. The overall survival rate, between three and five years, was 32.7%. Estrogen receptors were identified by using immunohistochemical assay ER-ICA and monoclonal antibody H222-SP gamma, Abbott. There were no differences in the complete response index, disease free interval and survival rates, among ER-positive and ER-negative patients, explained by the far advanced stage of the disease. ER-positivity was significantly correlated with histological features of the tumors: cell differentiation, presence of elastosis, absence of lymphocytic infiltration and absence of tumor necrosis.

Acute antibody-mediated rejection of renal transplant associated with cellular crescents: First case report

Acute antibody-mediated rejection is characterized by histological abnormalities such as glomerulitis, capillaritis, or thrombosis associated with presence of C4d and specific anti-donor antibodies. Reports on the association of glomerular injuries with cellular crescents in antibody-mediated rejection are not found in the literature. We report a unique case of antibody-mediated rejection associated with cellular crescents and suggest that such histological abnormality should be considered in the differential diagnosis of acute antibody-mediated rejection. © 2011 Elsevier Inc.

Anemia at one year is an independent risk factor of graft survival

Background Post-transplant anemia is multifactorial and highly prevalent. Some studies have associated anemia with mortality and graft failure. The purpose of this study was to assess whether the presence of anemia at 1 year is an independent risk factor of mortality and graft survival. Methods All patients transplanted at a single center who survived at least 1 year after transplantation and showed no graft loss (n = 214) were included. Demographic and clinical data were collected at baseline and at 1 year. Patients were divided into two groups (anemic and nonanemic) based on the presence of anemia (hemoglobin<130 g/l in men and 120 g/l in women). Results Baseline characteristics such as age, gender, type of donor, CKD etiology, rejection, andmismatches were similar in both groups. Creatinine clearance was similar in both anemic and nonanemic groups (69.32 ± 29.8 × 75.69 ± 30.5 ml/mim; P = 0.17). A Kaplan- Meier plot showed significantly poorer death-censored graft survival in the anemic group, P = 0.003. Multivariate analysis revealed that anemic patients had a hazard ratio for the graft loss of 3.85 (95% CI: 1.49-9.96; P = 0.005). Conclusions In this study, anemia at 1 year was independently associated with death-censored graft survival and anemic patients were 3.8-fold more likely to lose the graft. © 2010 Springer Science+Business Media, B.V.

Living kidney donors - a prospective study of quality of life before and after kidney donation

Although the safety of living kidney donation has been well established, prospective studies examining the physical and psychosocial aspects of the donor's quality of life are still scarce. Thus, the purpose of this prospective work was to assess the quality of life of 50 consecutive donors before and after kidney transplantation. All donors were asked to respond to both a donor questionnaire and the short-form 36-item health survey (SF-36). Interviews were individually conducted before, three months after, and over one yr after transplantation. Donation was considered a positive experience by all patients and had no impact on any physical or psychosocial aspect of the donor's life. Improved self-esteem and better quality of life after donation were reported in 52% of the cases. All donors would donate again and encouraged donation. SF-36 data indicated improvement in post-donation mental and physical scores among living donors closely related to recipient. Overall, most donors had a positive experience, felt no changes in quality of life, experienced enhanced self-esteem, would donate again, and recommended donation. © 2012 John Wiley & Sons A/S.

Treatment of adriamycin-induced nephropathy with erythropoietin and G-CSF

Background: Granulocyte colony-stimulating factor (G-CSF) and Erythropoietin (EPO) are known to stimulate the growth and differentiation of progenitor cells to prevent acute renal injury. This study aimed to assess the use of growth factors to mobilize stem cell in a mouse model of adriamycin-induced chronic kidney disease. Methods: All animals were injected with adriamycin for kidney injury and allocated into three treatment groups (G-CSF, EPO and G-CSF + EPO), and a control group (adriamycin alone). Results: Number of atrophic sites, glomerulosclerosis rate and interstitial fibrosis severity score were assessed in all groups. In all treatment groups, histologic parameters did not significantly differ, but were lower than in the control group (P<.001). Scal and CD34 expressions among treatment groups showed no statistically significant difference, but were higher than in the control group (P<.0001). CD105 expression was higher in EPO and G+EPO as compared to G-CSF and the control group (P<.0001), with no statistically significant difference between the latter two groups (P = NS). Conclusion: G-CSF and EPO had a histologic protective effect, while treatment with EPO + G-CSF had no additive effects in a model of adriamycin-induced chronic kidney disease. © 2013 Societá Italiana di Nefrologia.

Mononuclear inflammatory infiltrate and microcirculation injury in acute rejection: Role in renal allograft survival

This study aimed at investigating associations between monocytes/ macrophages (Mo) infiltration and three important criteria associated with acute antibody-mediated rejection: C4d staining, microcirculation injury, and graft survival time. By quantitative analysis, Mo were counted in peritubular capillaries and in the interstitial compartment (peritubular/interstitial Mo), and they were also identified in glomeruli (glomerular Mo). The study included 47 patients who received renal allograft between 1991 and 2009. Capillaritis and glomerulitis were classified by the Banff scoring system, and C4d and Mo were analyzed by immunohistochemistry. In the quantitative analysis, the mean values of 50 Mo per 10 high-power fields (HPF) and 4 Mo per glomerulus were used as cut-off points for the peritubular/interstitial and glomerular compartments, respectively. Positive C4d cases were associated with the groups of biopsies with a mean value ≥50 Mo per 10 HPF (p = 0.01) and ≥4 Mo per glomerulus (p = 0.02). The group with a mean value ≥4 Mo per glomerulus also showed association with the presence of glomerulitis (p = 0.02). Peritubular/ interstitial Mo did not associate with glomerulitis. Capillaritis did not show association with peritubular/interstitial or glomerular Mo. As regards graft survival, the infiltration of Mo in glomeruli interfered with allograft survival (p = 0.01). The group with a mean value of ≥4 glomerular Mo presented worse survival at the time of the 1-year follow-up. According to the literature, our data showed that infiltration of mononuclear cells was associated with C4d staining, microcirculation injury, and glomerulitis, in particular, and that glomerular macrophages could influence renal allograft survival. Copyright © 2013 Informa Healthcare USA, Inc.

Um novo sistema de refrigeração com controle de temperatura, compressor aberto, máquina de indução trifásica com velocidade variável e correção ativa do fator de potência do estágio de entrada

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Expressão dos capilares peritubulares (CD34) e do VEGF na nefropatia crônica do enxerto

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito sobre função renal de estimulantes de protogenitores hematopoiéticos na nefropatia por adriamicina

Pós-graduação em Fisiopatologia em Clínica Médica - FMB

Os 600 transplantes renais do Hospital das Clínicas da Faculdade de Medicina de Botucatu (HC da FMB) - UNESP: Mudanças ao longo do tempo

Introdução:Os resultados alcançados pelos transplantes renais nas últimas décadas têm melhorado progressivamente. Objetivo:A fim de determinar a extensão desse progresso, conduzimos uma análise dos resultados obtidos em nosso programa de transplantes através de três períodos diferentes. Métodos:Avaliamos os 600 transplantes renais realizados no HC FMB-UNESP até dezembro de 2011, subdividindo-os em três eras, de acordo com a imunossupressão vigente. Era 1: de 1987 a 2000 (n = 180); associação de ciclosporina e azatioprina. Era 2: de 2001 a 2006 (n = 120); associação de ciclosporina e micofenolato e Era 3: de 2007 a 2011 (n = 300); associação de tacrolimus e micofenolato. Resultados:Os resultados mostram aumento da idade média do receptor, da prevalência de diabetes e do número de transplantes com doador falecido (60%) na terceira era. O uso de terapia de indução foi de 75% era atual contra 46,6% (Era 2) e 3,9% (Era 1), p < 0,0001. Os dados de sobrevida geral por tipo de doador mostram dados semelhantes à literatura. Houve progressivo aumento da sobrevida do enxerto com doadores falecidos em 5 anos, saindo de 13,7% (Era 1) para 81,9% (Era 3). Conclusão:Houve significativas diferenças ao longo do tempo, culminando com aumento do volume de transplantes na atual era (média de 14 transplantes/ano na Era 1 para 75 transplantes/ano na Era 3). Inverteu-se o perfil de transplantes na era atual com predomínio de doador falecido. A melhor sobrevida com doador falecido da atual era foi atribuída a maior experiência do centro e aos esquemas de imunossupressão baseados na combinação de tacrolimus com micofenolato associados a esquema de indução.