15 resultados para Lines of transmission
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo
Resumo:
The need for increasing the loading capacity of transmission lines in a traditional way, by replacing or reinforcement of the structures and foundations on routes crossing areas considered of permanent environmental preservation, may require additional works that alter the environment. The present rigorous environmental legislation turns these changes and substitution unfeasible. One way to increase the capacity of these lines is the use of new conductor technology. The aim of this paper is to discuss the needs for upgrading a transmission line and minimize or eliminate the damage to the environment by using special conductors. Because the aluminum conductor composite reinforced technology is relatively new and considering the lack of information related to its effective performance in practical system, there is a need to verify the behavior of these conductors through monitoring procedures.
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BACKGROUND: In Brazil nationally representative donor data are limited on human immunodeficiency virus (HIV) prevalence, incidence, and residual transfusion risk. The objective of this study was to analyze HIV data obtained over 24 months by the Retrovirus Epidemiology Donor Study-II program in Brazil. STUDY DESIGN AND METHODS: Donations reactive to third-and fourth-generation immunoassays (IAs) were further confirmed by a less-sensitive (LS) IA algorithm and Western blot (WB). Incidence was calculated for first-time (FT) donors using the LS-EIA results and for repeat donors with a model developed to include all donors with a previous negative donation. Residual risk was projected by multiplying composite FT and repeat donor incidence rates by HIV marker-negative infectious window periods. RESULTS: HIV prevalence among FT donors was 92.2/ 105 donations. FT and repeat donor and composite incidences were 38.5 (95% confidence interval [CI], 25.651.4), 22.5 (95% CI, 17.6-28.0), and 27.5 (95% CI, 22.0-33.0) per 100,000 person-years, respectively. Male and community donors had higher prevalence and incidence rates than female and replacement donors. The estimated residual risk of HIV transfusion transmission was 11.3 per 106 donations (95% CI, 8.4-14.2), which could be reduced to 4.2 per 106 donations (95% CI, 3.2-5.2) by use of individual-donation nucleic acid testing (NAT). CONCLUSION: The incidence and residual transfusion risk of HIV infection are relatively high in Brazil. Implementation of NAT will not be sufficient to decrease transmission rates to levels seen in the United States or Europe; therefore, other measures focused on decreasing donations by at-risk individuals are also necessary.
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Background: In Cambodia, malaria transmission is low and most cases occur in forested areas. Seroepidemiological techniques can be used to identify both areas of ongoing transmission and high-risk groups to be targeted by control interventions. This study utilizes repeated cross-sectional data to assess the risk of being malaria sero-positive at two consecutive time points during the rainy season and investigates who is most likely to sero-convert over the transmission season. Methods: In 2005, two cross-sectional surveys, one in the middle and the other at the end of the malaria transmission season, were carried out in two ecologically distinct regions in Cambodia. Parasitological and serological data were collected in four districts. Antibodies to Plasmodium falciparum Glutamate Rich Protein (GLURP) and Plasmodium vivax Merozoite Surface Protein-119 (MSP-119) were detected using Enzyme Linked Immunosorbent Assay (ELISA). The force of infection was estimated using a simple catalytic model fitted using maximum likelihood methods. Risks for sero-converting during the rainy season were analysed using the Classification and Regression Tree (CART) method. Results: A total of 804 individuals participating in both surveys were analysed. The overall parasite prevalence was low (4.6% and 2.0% for P. falciparum and 7.9% and 6.0% for P. vivax in August and November respectively). P. falciparum force of infection was higher in the eastern region and increased between August and November, whilst P. vivax force of infection was higher in the western region and remained similar in both surveys. In the western region, malaria transmission changed very little across the season (for both species). CART analysis for P. falciparum in the east highlighted age, ethnicity, village of residence and forest work as important predictors for malaria exposure during the rainy season. Adults were more likely to increase their antibody responses to P. falciparum during the transmission season than children, whilst members of the Charay ethnic group demonstrated the largest increases. Discussion: In areas of low transmission intensity, such as in Cambodia, the analysis of longitudinal serological data enables a sensitive evaluation of transmission dynamics. Consecutive serological surveys allow an insight into spatio-temporal patterns of malaria transmission. The use of CART enabled multiple interactions to be accounted for simultaneously and permitted risk factors for exposure to be clearly identified.
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Objective: To evaluate cases of mother-to-child transmission of HIV-1 at multiple sites in Latin America and the Caribbean in terms of missed opportunities for prevention. Methods: Pregnant women infected with HIV-1 were eligible for inclusion if they were enrolled in either the NISDI Perinatal or LILAC protocols by October 20, 2009, and had delivered a live infant with known HIV-1 infection status after March 1, 2006. Results: Of 711 eligible mothers, 10 delivered infants infected with HIV-1. The transmission rate was 1.4% (95% CI, 0.7-2.6). Timing of transmission was in utero or intrapartum (n = 5), intrapartum (n = 2), intrapartum or early postnatal (n = 1), and unknown (n = 2). Possible missed opportunities for prevention included poor control of maternal viral load during pregnancy; late initiation of antiretrovirals during pregnancy; lack of cesarean delivery before labor and before rupture of membranes; late diagnosis of HIV-1 infection; lack of intrapartum antiretrovirals; and incomplete avoidance of breastfeeding. Conclusion: Early knowledge of HIV-1 infection status (ideally before or in early pregnancy) would aid timely initiation of antiretroviral treatment and strategies designed to prevent mother-to-child transmission. Use of antiretrovirals must be appropriately monitored in terms of adherence and drug resistance. If feasible, breastfeeding should be completely avoided. Presented in part at the XIX International AIDS Conference (Washington, DC; July 22-27, 2012); abstract WEPE163. (c) 2012 Published by Elsevier Ireland Ltd. on behalf of International Federation of Gynecology and Obstetrics.
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We apply Stochastic Dynamics method for a differential equations model, proposed by Marc Lipsitch and collaborators (Proc. R. Soc. Lond. B 260, 321, 1995), for which the transmission dynamics of parasites occurs from a parent to its offspring (vertical transmission), and by contact with infected host (horizontal transmission). Herpes, Hepatitis and AIDS are examples of diseases for which both horizontal and vertical transmission occur simultaneously during the virus spreading. Understanding the role of each type of transmission in the infection prevalence on a susceptible host population may provide some information about the factors that contribute for the eradication and/or control of those diseases. We present a pair mean-field approximation obtained from the master equation of the model. The pair approximation is formed by the differential equations of the susceptible and infected population densities and the differential equations of pairs that contribute to the former ones. In terms of the model parameters, we obtain the conditions that lead to the disease eradication, and set up the phase diagram based on the local stability analysis of fixed points. We also perform Monte Carlo simulations of the model on complete graphs and Erdös-Rényi graphs in order to investigate the influence of population size and neighborhood on the previous mean-field results; by this way, we also expect to evaluate the contribution of vertical and horizontal transmission on the elimination of parasite. Pair Approximation for a Model of Vertical and Horizontal Transmission of Parasites.
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In the past few decades detailed observations of radio and X-ray emission from massive binary systems revealed a whole new physics present in such systems. Both thermal and non-thermal components of this emission indicate that most of the radiation at these bands originates in shocks. O and B-type stars and WolfRayet (WR) stars present supersonic and massive winds that, when colliding, emit largely due to the freefree radiation. The non-thermal radio and X-ray emissions are due to synchrotron and inverse Compton processes, respectively. In this case, magnetic fields are expected to play an important role in the emission distribution. In the past few years the modelling of the freefree and synchrotron emissions from massive binary systems have been based on purely hydrodynamical simulations, and ad hoc assumptions regarding the distribution of magnetic energy and the field geometry. In this work we provide the first full magnetohydrodynamic numerical simulations of windwind collision in massive binary systems. We study the freefree emission characterizing its dependence on the stellar and orbital parameters. We also study self-consistently the evolution of the magnetic field at the shock region, obtaining also the synchrotron energy distribution integrated along different lines of sight. We show that the magnetic field in the shocks is larger than that obtained when the proportionality between B and the plasma density is assumed. Also, we show that the role of the synchrotron emission relative to the total radio emission has been underestimated.
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Objective: To analyze the shear forces on the vertebral body L4 when submitted to a compression force by means of transmission photoelasticity. Methods: Twelve photoelastic models were divided into three groups, with four models per group, according to the positioning of the sagittal section vertebrae L4-L5 (sections A, B and C). The simulation was performed using a 15N compression force, and the fringe orders were evaluated in the vertebral body L4 by the Tardy compensation method. Results: Photoelastic analysis showed, in general, a homogeneous distribution in the vertebral bodies. The shear forces were higher in section C than B, and higher in B than A. Conclusion: The posterior area of L4, mainly in section C, showed higher shear concentrations, corresponding to a more susceptible area for bone fracture and spondylolisthesis. Economic and Decision Analyses Development of an Economic or Decision Model. Level I
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Leprosy in children is correlated with community-level factors, including the recent presence of disease and active foci of transmission in the community. We performed clinical and serological examinations of 1,592 randomly selected school children (SC) in a cross-sectional study of eight hyperendemic municipalities in the Brazilian Amazon Region. Sixty-three (4%) SC, with a mean age of 13.3 years (standard deviation = 2.6), were diagnosed with leprosy and 777 (48.8%) were seropositive for anti-phenolic glycolipid-I (PGL-I). Additionally, we evaluated 256 household contacts (HHCs) of the students diagnosed with leprosy; 24 (9.4%) HHC were also diagnosed with leprosy and 107 (41.8%) were seropositive. The seroprevalence of anti-PGL-I was significantly higher amongst girls, students from urban areas and students from public schools (p < 0.0001). Forty-five (71.4%) new cases detected amongst SC were classified as paucibacillary and 59 (93.6%) patients did not demonstrate any degree of physical disability at diagnosis. The results of this study suggest that there is a high rate of undiagnosed leprosy and subclinical infection amongst children in the Amazon Region. The advantages of school surveys in hyperendemic areas include identifying leprosy patients at an early stage when they show no physical disabilities, preventing the spread of the infection in the community and breaking the chain of transmission.
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Influence of nutritional variables and obesity on health and metabolism Obesity is a recurring theme in current scientific literature. This can easily be explained by its exponential increase in all layers of society. The popularity of this subject has also given rise to associated questions, which have achieved greater prominence in health-related publications. In order to assess what has been studied in the field of obesity and nutrition, an overview of all articles published on these subjects in some of the main Brazilian scientific journals over the past two years was performed. Among the subthemes selected for this study, those related to childhood obesity attracted attention due to their greater frequency. These were subdivided into: prevalence, intrauterine and breastfeeding influences that may lead to the development of this condition, impact on quality of life, cardiovascular system and metabolism, and possible prevention strategies. Furthermore, issues related to obesity in adults were explored, such as risk factors and new strategies for prevention, with special attention given to the many studies evaluating different aspects of bariatric surgery. Finally, the subject of malnutrition and the impact of the deficiency of specific micronutrients such as selenium, vitamin D, and vitamin B12 were assessed. Based on the results, it was possible to assess the actual importance of obesity and nutrition in health maintenance, and also the several lines of research regarding these issues. Thus, it is essential to create new methods, which must be quick and efficient, to update health professionals involved in the treatment of obesity.
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Glioblastoma remains one of the most devastating human malignancies, and despite therapeutic advances, there are no drugs that significantly improve the patient survival. Altered expression of the Aurora kinases was found in different malignancies, and their inhibition has been studied in cancer therapy. In this study, we analyzed the expression of Aurora A and Aurora B in glioblastoma samples and also analyzed whether the effects of Aurora kinase inhibition were associated with temozolomide or not on cell lines and primary cultures of glioblastoma. RT-PCR assays were used to determine the mRNA expression in glioblastoma tumor samples and in the cell lines. Cell proliferation was measured by XTT assay, and apoptosis was determined by flow cytometry. Drug combination analyses were made based in Chou-Talalay method. Gamma radiation for clonogenic survival used the doses of 2, 4 and 6 Gy. Changes in Aurora B level were assessed by Western blot analysis. Aurora A and B were expressed in glioblastoma samples as well as in the glioblastoma cell lines (n = 6). Moreover, ZM447439, a selective Aurora kinase inhibitor, decreased the proliferation separately and synergistically with temozolomide in primary cultures and cell lines of glioblastoma. ZM also enhanced the effects of radiation on the two cell lines studied (U343 and U251), mainly when associated with TMZ in U343 cells. Treatment with ZM induced apoptotic cell death and diminished Aurora B protein level. These data suggest that Aurora kinase inhibition may be a target for glioblastoma treatment and could be used as adjuvant to chemo- and radiotherapy.
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Most of the antiretroviral (ARV) studies in Brazil have been reported in treatment-experienced and naive patients rather than in the setting of treatment interruption (TI). In this study, we analysed reasons given for TI and resistance mutations occurring in 150 HIV-1-infected patients who underwent TI. Of the patients analysed, 110 (73.3%) experienced TI following medical advice, while the remaining patients stopped antiretroviral therapy (ART) of their own accord. The main justifications for TI were: ARV-related toxicities (38.7%), good laboratory parameters (30%) and poor adherence (20%). DNA sequencing of the partial pol gene was successful in 137 (91.3%) patients, of whom 38 (27.7%) presented mutations conferring ARV resistance. A higher viral load prior to TI correlated with drug resistance (P < 0.05). Our results demonstrate that there are diverse rationales for TI and that detection of resistant strains during TI most likely indicates a fitter virus than the wild type. High viral loads coupled with unprotected sex in this group could increase the likelihood of transmission of drug-resistant virus. Thus, treating physicians should be alerted to this problem when the use of ARVs is interrupted.
Resumo:
Manganese tungstate (MnWO4) nanorods were prepared at room temperature by the co-precipitation method and synthesized after processing in a microwave-hydrothermal (MH) system at 140 degrees C for 6-96 min. These nanorods were structurally characterized by X-ray diffraction (XRD), Rietveld refinements and Fourier transform (FT)-Raman spectroscopy. The growth direction, shape and average size distribution of nanorods were observed by means of transmission electron microscopy (TEM) and high resolution TEM (HR-TEM). The optical properties of the nanorods were investigated by ultraviolet visible (UV-vis) absorption and photoluminescence (PL) measurements. XRD patterns, Rietveld refinement data and FT-Raman spectroscopy indicate that the MnWO4 precipitate is not a single phase structure while the nanorods synthesized by MH processing have a wolframite-type monoclinic structure without deleterious phases. FT-Raman spectra exhibited the presence of 17 Raman-active modes from 50 to 1,000 cm(-1). TEM and HR-TEM micrographs indicated that the nanorods are aggregated due to surface energy by Van der Waals forces and grow along the [100] direction. UV-vis absorption measurements confirmed non-linear values for the optical band gap (from 3.2 to 2.72 eV), which increased as the MH processing time increased. The structural characterizations indicated that the presence of defects in the MnWO4 precipitate promotes a significant contribution to maximum PL emission, while MnWO4 nanorods obtained by MH processing decrease the PL emission due to the reduction of defects in the lattice.
Resumo:
Abstract Background Saliva is a key element of interaction between hematophagous mosquitoes and their vertebrate hosts. In addition to allowing a successful blood meal by neutralizing or delaying hemostatic responses, the salivary cocktail is also able to modulate the effector mechanisms of host immune responses facilitating, in turn, the transmission of several types of microorganisms. Understanding how the mosquito uses its salivary components to circumvent host immunity might help to clarify the mechanisms of transmission of such pathogens and disease establishment. Methods Flow cytometry was used to evaluate if increasing concentrations of A. aegypti salivary gland extract (SGE) affects bone marrow-derived DC differentiation and maturation. Lymphocyte proliferation in the presence of SGE was estimated by a colorimetric assay. Western blot and Annexin V staining assays were used to assess apoptosis in these cells. Naïve and memory cells from mosquito-bite exposed mice or OVA-immunized mice and their respective controls were analyzed by flow cytometry. Results Concentration-response curves were employed to evaluate A. aegypti SGE effects on DC and lymphocyte biology. DCs differentiation from bone marrow precursors, their maturation and function were not directly affected by A. aegypti SGE (concentrations ranging from 2.5 to 40 μg/mL). On the other hand, lymphocytes were very sensitive to the salivary components and died in the presence of A. aegypti SGE, even at concentrations as low as 0.1 μg/mL. In addition, A. aegypti SGE was shown to induce apoptosis in all lymphocyte populations evaluated (CD4+ and CD8+ T cells, and B cells) through a mechanism involving caspase-3 and caspase-8, but not Bim. By using different approaches to generate memory cells, we were able to verify that these cells are resistant to SGE effects. Conclusion Our results show that lymphocytes, and not DCs, are the primary target of A. aegypti salivary components. In the presence of A. aegypti SGE, naïve lymphocyte populations die by apoptosis in a caspase-3- and caspase-8-dependent pathway, while memory cells are selectively more resistant to its effects. The present work contributes to elucidate the activities of A. aegypti salivary molecules on the antigen presenting cell-lymphocyte axis and in the biology of these cells.
Resumo:
BACKGROUND: Saliva is a key element of interaction between hematophagous mosquitoes and their vertebrate hosts. In addition to allowing a successful blood meal by neutralizing or delaying hemostatic responses, the salivary cocktail is also able to modulate the effector mechanisms of host immune responses facilitating, in turn, the transmission of several types of microorganisms. Understanding how the mosquito uses its salivary components to circumvent host immunity might help to clarify the mechanisms of transmission of such pathogens and disease establishment. METHODS: Flow cytometry was used to evaluate if increasing concentrations of A. aegypti salivary gland extract (SGE) affects bone marrow-derived DC differentiation and maturation. Lymphocyte proliferation in the presence of SGE was estimated by a colorimetric assay. Western blot and Annexin V staining assays were used to assess apoptosis in these cells. Naïve and memory cells from mosquito-bite exposed mice or OVA-immunized mice and their respective controls were analyzed by flow cytometry. RESULTS: Concentration-response curves were employed to evaluate A. aegypti SGE effects on DC and lymphocyte biology. DCs differentiation from bone marrow precursors, their maturation and function were not directly affected by A. aegypti SGE (concentrations ranging from 2.5 to 40 μg/mL). On the other hand, lymphocytes were very sensitive to the salivary components and died in the presence of A. aegypti SGE, even at concentrations as low as 0.1 μg/mL. In addition, A. aegypti SGE was shown to induce apoptosis in all lymphocyte populations evaluated (CD4+ and CD8+ T cells, and B cells) through a mechanism involving caspase-3 and caspase-8, but not Bim. By using different approaches to generate memory cells, we were able to verify that these cells are resistant to SGE effects. CONCLUSION: Our results show that lymphocytes, and not DCs, are the primary target of A. aegypti salivary components. In the presence of A. aegypti SGE, naïve lymphocyte populations die by apoptosis in a caspase-3- and caspase-8-dependent pathway, while memory cells are selectively more resistant to its effects. The present work contributes to elucidate the activities of A. aegypti salivary molecules on the antigen presenting cell-lymphocyte axis and in the biology of these cells.
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Glutamate acts as a neurotransmitter within the Central Nervous System (CNS) and modifies immune cell activity. In lymphocytes, NMDA glutamate receptors regulate intracellular calcium, the production of reactive oxygen species and cytokine synthesis. MK-801, a NMDA receptor open-channel blocker, inhibits calcium entry into mast cells, thereby preventing mast cell degranulation. Several lines of evidence have shown the involvement of NMDA glutamate receptors in amphetamine (AMPH)-induced effects. AMPH treatment has been reported to modify allergic lung inflammation. This study evaluated the effects of MK-801 (0.25mg/kg) and AMPH (2.0mg/kg), given alone or in combination, on allergic lung inflammation in mice and the possible involvement of NMDA receptors in this process. In OVA-sensitized and challenged mice, AMPH and MK-801 given alone decreased cellular migration into the lung, reduced IL-13 and IL10 levels in BAL supernatant, reduced ICAM-1 and L-selectin expression in granulocytes in the BAL and decreased mast cell degranulation. AMPH treatment also decreased IL-5 levels. When both drugs were administered, treatment with MK-801 reversed the decrease in the number of eosinophils and neutrophils induced by AMPH in the BAL of OVA-sensitized and challenged mice as well as the effects on the expression of L-selectin and ICAM-1 in granulocytes, the IL-10, IL-5 and IL-13 levels in BAL supernatants and increased mast cell degranulation. At the same time, treatment with MK-801, AMPH or with MK-801+AMPH increased corticosterone serum levels in allergic mice. These results are discussed in light of possible indirect effects of AMPH and MK-801 via endocrine outflow from the CNS (i.e., HPA-axis activity) to the periphery and/or as a consequence of the direct action of these drugs on immune cell activity, with emphasis given to mast cell participation in the allergic lung response of mice.