NUMERICAL AND EXPERIMENTAL STUDY OF A FREE INCOMPRESSIBLE ISOTHERMAL TURBULENT COAXIAL JET

In the present study the free incompressible isothermal turbulent coaxial jet problem is numerically solved, and compared with experimental measurements for different velocity ratio between the inner and the outer streams of the jet. The radial profile of the axial mean velocity was obtained with hot anemometry at different axial positions. Governing equations (mass conservation, momentum, turbulence model) were discretized employing the finite volume method with a segregated solver. The analysis of the experimental results showed that coaxial jet flow fields did not present self-similarity up to z/D=25, and the numerical solution using the Shih’s k ε turbulence model did not match reasonably with the experimental data, with a difference of about ± 10%

new considerations on substrate inhibition profile and catalytic mechanism

We would like to thank Fundacao para a Ciencia e Tecnologia for the financial support through grants SFRH/BD/39009/2007 (AGD), PDTC/QUI/64638/2006 (IM) and PDCT/QUI-BIOQ/1/6481/2010 (IM). REQUIMTE is funded by grant PEst-C/EQB/LA0006/2013 from FCT/MEC.Nitric oxide reductase (NOR) from denitrifying bacteria is an integral membrane protein that catalyses the two electron reduction of NO to N2O, as part of the denitrification process, being responsible for an exclusive reaction, the NN bond formation, the key step of this metabolic pathway. Additionally, this class of enzymes also presents residual oxidoreductase activity, reducing O2 to H2O in a four electron/proton reaction. In this work we report, for the first time, steady-state kinetics with the Pseudomonas nautica NOR, either in the presence of its physiological electron donor (cyt. c552) or immobilised on a graphite electrode surface, in the presence of its known substrates, namely NO or O2. The obtained results show that the enzyme has high affinity for its natural substrate, NO, and different kinetic profiles according to the electron donor used. The kinetic data, as shown by the pH dependence, is modelled by ionisable amino acid residues nearby the di-nuclear catalytic site. The catalytic mechanism is revised and a mononitrosyl-non-heme Fe complex (FeB(II)-NO) species is favoured as the first catalytic intermediate involved on the NO reduction.publishersversionpublishe

The role of drug use sequencing pattern in further problematic use of alcohol, tobacco, cannabis, and other drugs

Background: There has been considerable debate regarding what typically occurs after experimentation with drugs throughout the life of young people who used various drugs. Aims: To evaluate the clinical importance of the most common sequence for the first use of a drug by two models (the “gateway model” and the “alternative model”, which is the most popular sequence for Brazilian university students according to a previous study) regarding the problematic use of alcohol, tobacco, cannabis and other illegal drugs, assessed by ASSIST. Method: People who had already experimented with three or more drugs across different stages of the two models were selected from a representative sample of university students from 27 Brazilian capitals (n = 12 711). Findings: There were no differences regarding the problematic use of the most consumed drugs in Brazil (alcohol, tobacco and cannabis) between the models. Multiple drug seekers and violators had more problematic use of illegal drugs other than cannabis than individuals in the model sequence. However, in the case of violators, this was only evident in the alternative model. Conclusions: Multiple drug seekers and violators deserve special attention due to their increased risk of problematic use of other illegal drugs

The role of first use of inhalants within sequencing pattern of first use of drugs among Brazilian university students.

The present study investigated the role of first use of inhalants within a first drug sequencing pattern. In a representative sample of university students from 27 Brazilian capitals (n = 12,711), we analyzed the patterns of transition from/to first use of inhalants to/from the first use of alcohol, tobacco, cannabis, cocaine, hallucinogens, ecstasy, amphetamines, prescription opioids, and tranquilizers. Cox proportional hazards models were used to analyze data. Drugs that were not specified as the pair of drugs tested in each model were included as time-varying covariates in all models. In this sample, first use of inhalants was preceded only by the first use of alcohol and tobacco. However, first use of inhalants preceded first use of cannabis, amphetamines, cocaine, and tranquilizers. First use of inhalants preceded the first use of prescription opioids, and vice versa. This study highlights the need to intervene early with youths who are at risk of or just beginning to use inhalants, because this class of drugs seems to be the first illegal drug in Brazil to be experimented by respondents in our sample. There is also a call for attention to individuals who have already first used inhalants because of their higher chance to experiment with other drugs such as cannabis, cocaine, and prescription drugs. All these findings show an in-transition culture of drug use, which should be tracked through time, because some classical models (i.e., gateway model) might be outdated and might also not fit within different settings

Estabilidade do carbono presente na cama de frango e em seu respectivo biocarvão após aplicação no solo.

Resumo: A pesquisa teve como objetivo geral avaliar a degradação do carbono de biocarvão obtido a partir de cama de frango e determinar o efeito na capacidade de troca de cátions do solo. A aplicação do biocarvão de cama de frango como insumo é interessante para uso na agricultura, pois tem potencial para aumentar a CTC do solo e fornecer P às plantas, o que torna esse material bastante interessante para uso no solo em função do exposto e devido a outros benefícios como correção da acidez do solo, redução do Al tóxico, aumento do teor disponível de outros nutrientes e sequestro de carbono

Use transition between illegal drugs among Brazilian university students

Purpose: The aim of the present study was to test whether the first use of an illicit drug increases the chance of first use of other illicit drugs. Method: The transitions from the first use of a drug to the first use of another drug were analyzed. Comparisons were made between first drug users and non-users. Survival analysis methods were used to compare the cumulative probability of second drug use after adjusting for socio-demographic covariates and the intermediate use of alcohol and/or tobacco. A total of 12,721 Brazilian university students participated in this study. Results: Inhalants and marijuana were used prior to the use of several other drugs, whereas the opposite pattern was not found. Ecstasy was used before other drugs in several instances. Other well-examined drugs, such as amphetamines, cocaine and hallucinogens, were used both before and after other illicit drugs without any marked predominance for either of the two roles. Conclusions: This study supports the role of the use of marijuana and inhalants almost exclusively before the use of other illicit drugs, whereas the use of ecstasy has an opposite role. These roles could be linked to the prevalence of lifetime use and whether individuals were at an earlier or later age during experimentation

Diversificação da produção e transição agroecológica: uma experiência com SAF na várzea do Rio Capim - PA.

Os impactos negativos da agricultura convencional são apontados por diversos estudos, levando a proposições de modelos ecológicos e sistêmicos, como a agroecologia. Busca-se analisar os aspectos relacionados à transição agroecológica a partir de uma experiência com adoção de sistema agroflorestal no município de São Domingos do Capim - PA. Para a coleta de dados utilizou-se a caminhada transversal e entrevistas não-diretivas. A análise dos dados baseou-se em princípios da pesquisa qualitativa. A partir da análise da experiência pode-se inferir que o sistema de produção está em constante processo de transição agroecológica e social-agroecológica. A fundação da APEPA e ação desta refletem algumas características das dimensões política e socioeconômica-cultural da agroecologia. O SAF contribui para a diversidade de espécies e complexidade do agroecossistema e dos serviços ambientais, o que reflete a dimensão ecológica.Anais do SEMINÁRIO DE AGROECOLOGIA DA AMÉRICA DO SUL, 1; SEMINÁRIO DE AGROECOLOGIA DE MATO GROSSO DO SUL, 5.; ENCONTRO DE PRODUTORES AGROECOLOGICOS DE MATO GROSSO DO SUL, 4.; SEMINÁRIO DE SISTEMAS AGROFLORESTAIS EM BASES AGROECOLOGICA DE MATO GROSSO DO SUL, 1., 2014, Dourados

Produtividade e custos de produção da silagem de sorgo, milheto e girassol cultivados em agricultura de sequeiro para alimentação de ovinos no Semiárido brasileiro.

Resumo: Objetivou-se avaliar a produtividade e custos de produção da silagem de sorgo, milheto e girassol em sistema de agricultura de sequeiro para alimentação de ovinos. Foi estimada a produção de biomassa de forragem total e simulada a quantidade de ovinos possíveis de serem alimentados em área formada em 1,0 hectare com o material ensilado de cada cultura durante a época seca do ano. Quanto à produção de biomassa e de silagem em kg MS ha-1, o sorgo forrageiro foi a cultura que apresentou maior produtividade, com 8.262,5 e 7.023,1 kg MS ha-1, possibilitando a alimentação de cerca de 43 ovinos durante 8 meses. Quanto aos custos de produção, pode-se observar que os maiores valores foram obtidos na produção de silagem de girassol contendo 50% de sorgo, decorrente da baixa produtividade da cultura do girassol em relação às demais. As despesas com cercamento da área foi o item que mais onerou os custos de investimento. O custo operacional efetivo, custo operacional total e o custo total foram maiores para a silagem de girassol, com 50% de sorgo em relação às demais culturas, atingindo um custo total de R$4.993,58. O sorgo forrageiro (híbrido BRS 610) apresenta maior potencial para a produção de silagem em sistema de agricultura de sequeiro no Semiárido brasileiro. Todavia mais estudos devem ser realizados com o intuito de avaliar outras variedades melhores adaptadas a região. [Productivity and production costs of sorghum, pearl millet and sunflower silage cultivated in dry farming to sheep feeding in Brazilian semiarid]. Abstract: The aim of this research was to evaluate productivity and production costs of forage sorghum silage, pearl millet silage and sunflower silage cultivated in dry farming to the sheep nutrition. The forage biomass was estimated and a simulation of the amount of animals would be able to be feed with those silages was done. Sorghum had the greater biomass and silage production (8262.5 kg DM ha-1), allowing to feed 43 animals during eight months. Regarding production cost, it could be observed that sunflower silage had the highest cost due to the low field production, and the necessity of mixing it with 50$ 4993.58. Sorghum (hybrid BRS 610) has a greater potential to silage production in dry based systems, however more studies are need to evaluate other potential species

Produtividade e custos de produção de silagem para alimentação de ovinos a partir de sorgo, milheto e girassol.

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Antifungal and anti-biofilm activity of designed derivatives from kyotorphin

© 2019 British Mycological Society. Published by Elsevier Ltd. All rights reserved.Kyotorphin (KTP, l-tyrosyl-l-arginine) is an endogenous analgesic neuropeptide first isolated from bovine brain in 1979. Previous studies have shown that kyotorphins possess anti-inflammatory and antimicrobial activity. Six kyotorphins—KTP-NH2, KTP–NH2–DL, ibuprofen-conjugated KTP (IbKTP), IbKTP-NH2, N-methyl-D-Tyr-L-Arg, and N-methyl-L-Tyr-D-Arg—were designed and synthesized to improve lipophilicity and resistance to enzymatic degradation. This study assessed the antimicrobial and antibiofilm activity of these peptides. The antifungal activity of kyotorphins was determined in representative strains of Candida species, including Candida albicans ATCC 10231, Candida krusei ATCC 6258, and six clinical isolates—Candida dubliniensis 19-S, Candida glabrata 217-S, Candida lusitaniae 14-S, Candida novergensis 51-S, Candida parapsilosis 63, and Candida tropicalis 140-S—obtained from the oral cavity of HIV-positive patients. The peptides were synthesized by standard solution or solid-phase synthesis, purified by RP-HPLC (purity >95 %), and characterized by nuclear magnetic resonance. The results of the broth microdilution assay and scanning electron microscopy showed that IbKTP-NH2 presented significant antifungal activity against Candida strains and antibiofilm activity against the clinical isolates. The absence of toxic activity and survival after infection was assessed after injecting the peptide in larvae of Galleria mellonella as experimental infection model. Furthermore, IbKTP-NH2 had strong antimicrobial activity against multidrug-resistant bacteria and fungi and was not toxic to G. mellonella larvae up to a concentration of 500 mM. These results suggest that IbKTP-NH2, in addition to its known effect on cell membranes, can elicit a cellular immune response and, therefore, is promising for biomedical application.This research was supported by FAPESP (Grant No. 2017/00032-0). This article is also part of the Fungal Adaptation to Hostile Challenges special issue for the third International Symposium on Fungal Stress (ISFUS), which is supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (Grant No. 2018/20571-6) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (Grant No. 88881.289327/2018-01).info:eu-repo/semantics/publishedVersio