903 resultados para Viral Fusion


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Effects of the nonlocality of factorizable potentials are taken into account in the calculation of nucleus-nucleus fusion cross section through an effective mass approach. This cross section makes use of the tunneling factor calculated for the nonlocal barrier, without the explicit introduction of any result coming from coupled channel calculation, besides the approximations of Hill-Wheeler and Wong. Its new expression embodies the nonlocal effects in a factor which redefines the local potential barrier curvature. Applications to different systems, namely O-16 + Co-59, O-16,O-18 + Ni-58,Ni-60,Ni-64, and O-16,O-18 + Cu-63,Cu-65 are presented, where the nonlocal range is treated as a free parameter.

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Objectives: To compare modes and sources of infection and clinical and biosafety aspects of accidental viral infections in hospital workers and research laboratory staff reported in scientific articles. Methods: PubMed, Google Scholar, ISI Web of Knowledge, Scirus, and Scielo were searched (to December 2008) for reports of accidental viral infections, written in English, Portuguese, Spanish, or German; the authors' personal file of scientific articles and references from the articles retrieved in the initial search were also used. Systematic review was carried out with inclusion criteria of presence of accidental viral infection's cases information, and exclusion criteria of absence of information about the viral etiology, and at least probable mode of infection.Results: One hundred and forty-one scientific articles were obtained, 66 of which were included in the analysis. For arboviruses, 84% of the laboratory infections had aerosol as the source; for alphaviruses alone, aerosol exposure accounted for 94% of accidental infections. of laboratory arboviral infections, 15.7% were acquired percutaneously, whereas 41.6% of hospital infections were percutaneous. For airborne viruses, 81% of the infections occurred in laboratories, with hantavirus the leading causative agent. Aerosol inhalation was implicated in 96% of lymphocytic choriomeningitis virus infections, 99% of hantavirus infections, and 50% of coxsackievirus infections, but infective droplet inhalation was the leading mode of infection for severe acute respiratory syndrome coronavirus and the mucocutaneous mode of infection was involved in the case of infection with influenza B. For blood-borne viruses, 92% of infections occurred in hospitals and 93% of these had percutaneous mode of infection, while among laboratory infections 77% were due to infective aerosol inhalation. Among blood-borne virus infections there were six cases of particular note: three cases of acute hepatitis following hepatitis C virus infection with a short period of incubation, one laboratory case of human immunodeficiency virus infection through aerosol inhalation, one case of hepatitis following hepatitis G virus infection, and one case of fulminant hepatitis with hepatitis B virus infection following exposure of the worker's conjunctiva to hepatitis B virus e antigen-negative patient saliva. of the 12 infections with viruses with preferential mucocutaneous transmission, seven occurred percutaneously, aerosol was implicated as a possible source of infection in two cases, and one atypical infection with Macacine herpesvirus 1 with fatal encephalitis as the outcome occurred through a louse bite. One outbreak of norovirus infection among hospital staff had as its probable mode of infection the ingestion of inocula spread in the environment by fomites.Conclusions: The currently accepted and practiced risk analysis of accidental viral infections based on the conventional dynamics of infection of the etiological agents is insufficient to cope with accidental viral infections in laboratories and to a lesser extent in hospitals, where unconventional modes of infection are less frequently present but still have relevant clinical and potential epidemiological consequences. Unconventional modes of infection, atypical clinical development, or extremely severe cases are frequently present together with high viral loads and high virulence of the agents manipulated in laboratories. In hospitals by contrast, the only possible association of atypical cases is with the individual resistance of the worker. Current standard precaution practices are insufficient to prevent most of the unconventional infections in hospitals analyzed in this study; it is recommended that special attention be given to flaviviruses in these settings. (C) 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

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Samples with a composition of 40InF 3-20ZnF 2-5MCl- xBaF 2-ySrF 2, where M=Na, Li and x+y=35 mol%, were prepared. The thermal properties related to the Ba/Sr ratio and to the remaining chlorine content in the glasses were studied. Thermal stability is improved with the addition of chlorine. However, chlorine concentration is regulated by the sublimation of indium fluorides which takes place at about 600°C. Indium fluorides arc formed during glass fusion. The mechanisms of chlorine sublimation were studied. © 2005 Akadémiai Kiadó, Budapest.

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This project has been developed to evaluate the possible relationship between the cesspit (pit latrine) in as far as it degrades the quality of underground water. Its importance is due to the fact that in the rural communities in the State of São Paulo (Brazil) this type of cesspit is very common as a means of sewage disposal and these communities use underground water for their supply of drinking water. Rural properties distributed over the rural area in the municipality of São José do Rio Preto were selected. A preliminary study was then set up to determine the social situation and health of the households as well as qualitative evaluations on the type of water supply and sewage disposal of these communities. Campaigns of water sampling then followed and laboratory analyses of water taken from wells were carried out. Parameters were set up to evaluate the potability according to Brazilian legislation (2004) paying attention to microbiologic (coliforms, Crytosporidium sp., and adenovirus). The analyses showed evidence of possible interaction between the wells and the sewage effluents and drainage in these communities. A PCR reaction to detect adenovirus showed a presence in 53.3% of the samples. The tests for the detection of Cryotosporidium sp all showed a negative result.

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The cationic polysaccharide chitosan has been widely used for non-viral transfection in vitro and in vivo and has many advantages over other polycations. Chitosan is biocompatible and biodegradable and protects DNA against DNase degradation. However following administration the ChitosanDNA polyplexes must overcome a series of barriers before DNA is delivered to the cell nucleus. This paper describes the most important parameters involved in the chitosan-DNA interaction and their effects of on the condensation, shape, size and protection of DNA. Strategies developed for chitosanDNA polyplexes to avoid non-specific interaction with blood components and to overcome intracellular obstacles as the crossing of die cell membrane, endosomal escape and nuclear import are presented. © 2006 American Chemical Society.

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Kaposi's sarcoma-associated herpesvirus (KSHV/human herpesvirus 8 [HHV8]) and Epstein-Barr virus (EBV/HHV4) are distantly related gammaherpesviruses causing tumors in humans. KSHV latency-associated nuclear antigen 1 (LANA1) is functionally similar to the EBV nuclear antigen-1 (EBNA1) protein expressed during viral latency, although they have no amino acid similarities. EBNA1 escapes cytotoxic lymphocyte (CTL) antigen processing by inhibiting its own proteosomal degradation and retarding its own synthesis to reduce defective ribosomal product processing. We show here that the LANA1 QED-rich central repeat (CR) region, particularly the CR2CR3 subdomain, also retards LANA1 synthesis and markedly enhances LANA1 stability in vitro and in vivo. LANA1 isoforms have half-lives greater than 24 h, and fusion of the LANA1 CR2CR3 domain to a destabilized heterologous protein markedly decreases protein turnover. Unlike EBNA1, the LANA1 CR2CR3 subdomain retards translation regardless of whether it is fused to the 5′ or 3′ end of a heterologous gene construct. Manipulation of sequence order, orientation, and composition of the CR2 and CR3 subdomains suggests that specific peptide sequences rather than RNA structures are responsible for synthesis retardation. Although mechanistic differences exist between LANA1 and EBNA1, the primary structures of both proteins have evolved to minimize provoking CTL immune responses. Simple strategies to eliminate these viral inhibitory regions may markedly improve vaccine effectiveness by maximizing CTL responses. Copyright © 2007, American Society for Microbiology. All Rights Reserved.

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Biometrics is one of the biggest tendencies in human identification. The fingerprint is the most widely used biometric. However considering the automatic fingerprint recognition a completely solved problem is a common mistake. The most popular and extensively used methods, the minutiae-based, do not perform well on poor-quality images and when just a small area of overlap between the template and the query images exists. The use of multibiometrics is considered one of the keys to overcome the weakness and improve the accuracy of biometrics systems. This paper presents the fusion of a minutiae-based and a ridge-based fingerprint recognition method at rank, decision and score level. The fusion techniques implemented leaded to a reduction of the Equal Error Rate by 31.78% (from 4.09% to 2.79%) and a decreasing of 6 positions in the rank to reach a Correct Retrieval (from rank 8 to 2) when assessed in the FVC2002-DB1A database. © 2008 IEEE.

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Background & Aims Patients infected with hepatitis C virus (HCV) genotype 1, body weight <85 kg, and high baseline viral load respond poorly to standard doses of pegylated interferon (peginterferon) and ribavirin. We evaluated intensified therapy with peginterferon alfa-2a plus ribavirin. Methods This double-blind randomized trial included HCV genotype 1-infected outpatients from hepatology clinics with body weight <85 kg and HCV RNA titer <400,000 IU/mL. Patients were randomized to 180 μg/wk peginterferon alfa-2a for 48 weeks plus 1200 mg/day ribavirin (standard of care) (group A, n = 191) or 1400/1600 mg/day ribavirin (group B, n = 189). Additional groups included 360 μg/wk peginterferon alfa-2a for 12 weeks then 180 μg/wk peginterferon alfa-2a for 36 weeks plus 1200 mg/day ribavirin (group C, n = 382) or 1400/1600 mg/day ribavirin (group D, n = 383). Follow-up lasted 24 weeks after treatment. Results Sustained virologic response rates (HCV RNA level <15 IU/mL at end of follow-up) in groups A, B, C, and D were 38%, 43%, 44%, and 41%, respectively. There were no significant differences among the 4 groups or between pooled peginterferon alfa-2a regimens (A + B vs C + D: odds ratio [OR], 1.08; 95% confidence interval [CI], 0.831.39; P = .584) or pooled ribavirin regimens (A + C vs B + D: OR, 1.00; 95% CI, 0.791.28; P = .974). Conclusions In patients infected with HCV genotype 1 who are difficult to treat (high viral load, body weight <85 kg), a 12-week induction regimen of peginterferon alfa-2a and/or higher-dose ribavirin is not more effective than the standard regimen. © 2010 AGA Institute.

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The purpose of the present study was to evaluate the antimicrobial activity of propolis extracts diluted in different solvents against bacteria from Staphylococcus genus. The study was performed in the Immunology and Microbiology Laboratory from Universidade Federal do Vale do São Francisco. The propolis extracts were prepared using brown propolis diluted in different solvents such as chloroform, methanol, ethyl acetate and grain alcohol. In order to determine the antimicrobial potential of extracts, agar well diffusion method was used, with controls for each diluent. After that, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods were used. All tests were performed in triplicate. In the agar well diffusion test, the measurements of the inhibition zone for propolis extract were as follows: grain alcohol and propolis (2.88mm), methanol and propolis (2.41mm), chloroform and propolis (2.40mm) and ethyl acetate and propolis (0.83mm). The MBC of propolis extracts in different solvents were 93.75 μg/mL for grain alcohol, 375 μg/mL for chloroform and methanol and 3,000 μg/ml for ethyl acetate. Statistically significant differences were achieved comparing the inhibition zones of propolis diluted in grain alcohol and ethyl acetate (2.88 and 0.83 mm, respectively). Considering the low cost of therapy and the activity of the propolis against caprine mastitis pathogens, other studies regarding in vivo activity and chemical characterization are necessary, in addition to evaluation of the toxicological aspects of propolis extracts.

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The most important pathogens in the bovine livestock nowadays in the virus of the viral diarrhea mainly for triggered clinical manifestations related to the reproductive sphere. The infection in pregnant females, may result in abortions, embryonic resorptions, fetal mummification, birth of weak and malformation of the cattle. Moreover, their birth with persistently infected and immunotolerant virus, which the source of infection and dissemination of their disease. Nowadays, the complexity of the diagnosis and consequently its pathogenesis are tilted in the genotypic differences agent. So, this study aimed to verify the occurrence of the BVDV-1 (SINGER) and BVDV-2 (VS-253) genotypes in cows and their respective fetuses, slaughtered in an abattoir in the State of Sao Paulo. Through blood serum, using virus neutralization technique. All in all, 52,51% (115/219) of the cows which were tested reacted, but no fetus (0/219) reacted, to its virus neutralization. Through this cross-examination we observed that 42% (92/219) of cows reacted for both BVDV-1 and BVDV-2. Furthermore 4,10% (9/219) of them reacted only to the genotype BVDV-1 and 6,39% (14/219) responded only to the genotype 2 of BVDV. Therefore it was noticed that both strains are widespread in the regions studied, which justifies the use of different antigens to avoid false-negative diagnosis. Finally antibodies showed no fetus or fetal abnormalities, it is already developed and can be considered immunocompetent, independent child born to a reagent.