Bimetallic Thin-Walled Box Beam Thermal Buckling Response.

A beam model for thermal buckling analysis of a bimetallic box beam is presented. The Euler-Bernoulli-Vlasov beam theory is employed considering large rotations but small strains. The nonlinear stability analysis is performed using an updated Lagrangian formulation. In order to account for the thermal effects of temperature-dependent (TD) and temperature-independent (TID) materials, a uniform temperature rise through beam wall thickness is considered. The numerical results for thin-walled box beams are presented to investigate the effects of different boundary conditions, beam lengths and material thickness ratios on the critical buckling temperature and post-buckling responses. The effectiveness and accuracy of the proposed model are verified by means of comparison with a shell model. It is revealed that all of the abovementioned effects are invaluable for buckling analysis of thin-walled beams under thermal load. Moreover, it is shown that the TD solutions give lower values than the TID one, emphasizing the importance of TD materials in beams.

Removal of paracetamol from aqueous solution by activated carbon and silica. Experimental and computational study.

The presence of pharmaceutical residues in the aquatic environment is a known problem worldwide. Paracetamol is widely used as an analgesic and antipyretic. Its high consumption implies a continuous discharge in aqueous environments through industrial and domestic wastewater that requires mitigation and remediation strategies. The aim of the present study was to analyse the removal of the paracetamol from aqueous solutions using the adsorption technique. For this, three commercial adsorbents with different textural properties were used: two activated carbons (CAT and CARBOPAL) and silica gel. A series of batch adsorption experiments were conducted at different values of pH (3.0, 7.0 and 10.5) and ionic strength (0.01, 0.5 and 1 M) to investigate the effects on the removal of paracetamol from the aqueous solution. In addition, we investigated the adsorption mechanism using the density functional theory. Adsorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the adsorbents and degree of ionization of the paracetamol. Adsorption capacity of the adsorbents increased with an increase in the ionic strength of solution. At 25 °C, pH 3, ionic strength 1 M, 167 mg L-1 of adsorbent and initial concentrations of paracetamol between 25 and 150 mg L-1, the maximum adsorption capacity was 560 mg g-1, 450 mg g-1 and 95 mg g-1, for CAT, CARBOPAL and silica respectively. The experimental kinetic data fitted well the pseudo-second order model and the equilibrium isotherm data the Langmuir model. The functional density theory methods provided atomistic details about paracetamol adsorbed on the surface of carbon and silica through molecular modeling.

Adsorption of bentazone and imazapyc from water by using functionalized silica: Experimental and computational analysis.

In this study, silica and functionalized silica materials (3-aminopropyl and 3-mercapto derivatives) were successfully used for the removal of the pesticides bentazone and imazapyc from aqueous solutions. Adsorbent materials were characterized by BET isotherms and FT-IR spectroscopy (confirming the functionalization), and their equilibrium adsorption capacity was evaluated at different ionic strengths. It is observed that the maximum adsorption capacities decrease in the order 3-aminopropyl-derivative > silica >3-mercaptopropyl derivative. An increase in ionic strength produces an enhancement in the removal of pesticides. All isotherms are Ib-type and follow the Langmuir model, suggesting a monolayer physical adsorption process.

Adsorption and removal of phenoxy acetic herbicides from water by using commercial activated carbons: experimental and computational studies.

In this study, commercial activated carbons (GAB and CBP) were successfully used for the removal of two phenoxy acetic class-herbicides, 4-chloro-2-methyl phenoxy acetic acid and 2.4-dichlorophenoxy acetic acid (MCPA and 2.4-D) from aqueous solution. The adsorbent materials were characterized, and their equilibrium adsorption capacity was evaluated. The results suggest that the microporous properties of GAB activated carbon enhanced the adsorption capacity, in comparison to CBP carbon. Thus, the increasing in the ionic strength favored the adsorption removal of both pesticides, indicating that electrostatic interactions between the pollutant and the adsorbate surface are governing the adsorption mechanism, but increasing pH values decreased adsorption capacity. Experimental data for equilibrium was analyzed by two models: Langmuir and Freundlich. Finally, computational simulation studies were used to explore both the geometry and energy of the pesticides adsorption.

Animal infections by vaccinia-like viruses in the state of Rio de Janeiro: an expanding disease / Infecções animais por vírus semelhantes ao vaccínia no estado do Rio de Janeiro: uma doença em expansão

In the present study we investigated the presence of infections by vaccinia-like viruses in dairy cattle from 12 counties in the state of Rio de Janeiro in the last 9 years. Clinical specimens were collected from adult animals with vesicular/pustular lesions mainly in the udder and teats, and from calves with lesions around the nose and mouth. A plaque reduction neutralization test (PRNT) was applied to search for antibodies to Orthopoxvirus; the vesicular/pustular fluids and scabs were examined by PCR, electron microscopy (EM) and by inoculation in VERO cells for virus isolation. Antibodies to Orthopoxvirus were detected in most cases. The PCR test indicated a high nucleotide homology among the isolates and the vaccinia viruses (VACV) used as controls. By EM, typical orthopoxvirus particles were observed in some specimens. The agents isolated in tissue culture were confirmed as vaccinia-like viruses by EM and PCR. The HA gene of the vaccinia-like Cantagalo/IOC virus isolated in our laboratory was sequenced and compared with other vaccinia-like isolates, showing high homology with the original Cantagalo strain, both strains isolated in 1999 from dairy cattle. Antibodies to Orthopoxvirus were detected in one wild rodent (genus Akodon sp.) collected in the northwestern region of the state, indicating the circulation of poxvirus in this area. Nonetheless, PCR applied to tissue samples collected from the wild rodents were negative. Vesicular/pustular lesions in people in close contact with animals have been also recorded. Thus, the vaccinia-like virus infections in cattle and humans in the state seem to be an expanding condition, resulting in economic losses to dairy herds and leading to transient incapacitating human disease. Therefore, a possible immunization of the dairy cattle in the state should be carefully evaluated.

Neste estudo avaliou-se a presença de infecções por vírus semelhantes ao vírus vaccínia (VACV) em gado leiteiro em 12 municípios no estado do Rio de Janeiro, ao longo dos últimos nove anos. Amostras clínicas foram coletadas de animais com vesículas, pústulas e crostas no úbere e tetas, e da região do nariz e da cavidade oral de bezerros. Um teste de neutralização viral por redução de placas foi desenvolvido para investigar a presença de anticorpos contra Orthopoxvirus. Os fluidos de vesículas / pústulas e as crostas foram testadas por PCR, microscopia eletrônica (ME) e por inoculação em células VERO para isolamento viral. Anticorpos contra Orthopoxvirus foram detectados na grande maioria dos animais. O teste de PCR demonstrou homologia entre os vírus isolados e amostras de vírus vaccínia usados como controles. Na ME, partículas típicas de Orthopoxvirus foram observadas em vários espécimes analisados. Os vírus isolados em cultivo celular foram confirmados como Orthopoxvirus por PCR e ME. O gene HA da amostra Cantagalo/IOC isolada em nosso laboratório foi seqüenciado e comparado com outras amostras semelhantes ao vaccínia, mostrando uma alta homologia com a amostra original Cantagalo, tendo sido as duas amostras isoladas em 1999 de gado leiteiro. Anticorpos para Orthopoxvirus foram detectados em um roedor silvestre do gênero Akodon sp. coletado na região noroeste do estado, sugerindo uma circulação de poxvírus na natureza. No entanto, os testes de PCR aplicados a tecidos de roedores silvestres foram negativos. Infecções vesiculares / pustulares em humanos que mantinham contato com os animais afetados também foram relatadas. Assim, infecções por amostras semelhantes ao vírus VACV em bovinos e em humanos parecem em expansão no estado, gerando perdas econômicas em animais e quadros de doença incapacitante temporária em pacientes humanos. Dessa forma, a possibilidade da imunização do gado leiteiro no estado deve ser devidamente avaliada.

HIV-1: avaliação da resistência às drogas antiretrovirais em pacientes pediátricos / HIV-1: evaluation of resistance to antiretroviral drugs in pediatric patients

A utilização da terapia antiretroviral, atualmente mais amplamente acessível, implica na permanência da identificação da resistência viral e monitoramento da doença como itens importantes em adultos e pacientes pediátricos infectados pelo vírus da imunodeficiência humana tipo 1. Os principais marcadores da infecção por HIV-1, utilizados no monitoramento da infecção e curso da doença, são as contagens de células T CD4+ e a carga viral. Ambos são úteis como parâmetros indicadores para o início da terapia e na avaliação de sua eficácia. Além disto, a sua associação a testes de genotipagem para a identificação de mutações de resistência viral, pode auxiliar na indicação da conduta clínica mais adequada. No presente estudo, analisamos os valores da carga viral e taxas de linfócitos T CD4+ e CD8+ na avaliação do status imunológico de 25 crianças com indicação para a terapia antiretroviral, condicionando o regime terapêutico aos resultados do teste de genotipagem. A identificação dos subtipos virais foi feita por análise filogenética e a genotipagem incluiu a análise dos genes protease e transcriptase reversa do HIV-1. Dezoito amostras foram agrupadas no subtipo viral B e três no subtipo F1; cepas recobinantes também foram observadas, sendo uma BF, duas BD e uma DF. Dezoito crianças apresentaram mutações conferindo resistência viral aos inibidores da transcriptase reversa análogos de nucleosídeo e sete crianças apresentaram resistência aos inibidores não-análogos, com seis relatando resistência a nevirapina, delavirdina e efavirenz. Além disto, duas crianças, nas quais a terapia havia sido descontinuada dois a três anos antes da avaliação do teste de genotipagem, apresentaram as mutações K101E, K103N e G190A, conferindo resistência às três drogas. As mutações mais frequentes para o gene da transcriptase reversa foram observadas nos codons M41L, M184V e T215FY...

With antiretroviral therapy becoming more widely available nowadays. Human Immunodeficiency Virus type 1 resistance identification and monitoring of disease remains of great importance in adults and infected children. The major HIV-1 infection markers usually used for monitoring viral infection and disease course are CD4+ T cell counts or percentages and HIV viral load. Both of them are helpful indicating when to start therapy and evaluating its efficacy. Also, their association with genotyping tests to identify viral resistant mutations may help clinicians for the most adequate clinical conduct. In the present study, we assessed HIV-1 viral load and CD4+ and CD8+ T lymphocyte rates for the immunological status evaluation of 25 antiretroviral-treated children managing therapeutic regimens according to genotyping test results. Drug resistance evaluation was done using genotyping covering protease and reverse transcriptase genes. Additionally, all of the 25 vertically HIV-1 infected children were assessed for viral subtyping throughout phylogenetic analysis. Eighteen samples clustered at B subtype and three clustered at F1 subtype; one BF, two BD and one DF recobinant strains were also observed. Eighteen children presented, at least, one mutation conferring resistance to the nucleoside reverse transcriptase inhibitors, and seven children presented resistance to the non-nucleoside inhibitors, with six resistant to all three drugs, nevirapine, delavirdine, and efavirenz. In addition, two children in whom the therapy had been discontinued two to three years before testing presented K101E, K103N, and G190A mutations conferring resistance to the all three drugs. Reverse transcriptase gene mutations were more frequently observed at codons M41L, M184V, and T215FY. However, ten children presented and important number of viral resistance mutations, ranging from five to ten mutations, coferring resistance to at least four to up to eleven antiretroviral drugs...

Estudo clinico, laboratorial e da histologia hepática de candidatos a doadores de sangue HBsAg positivos em Belo Horizonte / Volunters blood donnors HBsAg positives in Belo Horizonte, State of Minas Gerais, Brasil : Clinical, laboratorial and histological study

Duzentos e cinquenta e dois candidatos a doadores de sangue HBsAg positivos (media de idade= 32,6 anos, 97,7masculino) foram investigados num estudo transversal para determinar suas caracteristicas clinicas, laboratoriais e histologicas. Foi tambem comparada a positividade e a negatividade dos marcadores sorologicos HBeAg, anti-HBe e IgM anti-HBc com os valores das aminotransferases sericas...