hybridModels: An R Package for the Stochastic Simulation of Disease Spreading in Dynamic Networks

Disease spreading simulations are traditionally performed using coupled differential equations. However, in the setting of metapopulations, most of the solutions provided by this method do not account for the dynamic topography of subpopulations. Conversely, the alternative approach of individual-based modeling (IBM) may add computational cost and complexity. Hybrid models allow for the study of disease spreading because they combine both aforementioned approaches by separating them across different scales: a local scale that addresses subpopulation dynamics using coupled differential equations and a global scale that addresses the contact between these subpopulations using IBM. We present a simple way of simulating the spread of disease in dynamic networks using the high-level statistical computational language R and the hybridModels package. We built four examples using disease spread models at the local scale in several different networks: an animal movement network; a three-node network, whose model solution using a stochastic simulation algorithm is compared with the ordinary differential equations approach; the commuting of individuals between patches, which we compare with the permanent migration of individuals; and the commuting of individuals within the metropolitan area of São Paulo

Obtaining high purity silica from rice hulls

Many routes for extracting silica from rice hulls are based on direct calcining. These methods, though, often produce silica contaminated with inorganic impurities. This work presents the study of a strategy for obtaining silica from rice hulls with a purity level adequate for applications in electronics. The technique is based on two leaching steps, using respectively aqua regia and Piranha solutions, which extract the organic matrix and inorganic impurities. The material was characterized by Fourier-transform infrared spectroscopy (FTIR), powder x-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy (SEM), particle size analysis by laser diffraction (LPSA) and thermal analysis

Cleaning Validation: A Case Study Involving Dexamethasone Cream

In order to achieve a reliable degree of quality, the pharmaceutical industry needs to introduce a quality control system that includes validation of the cleaning of equipment. This study carried out cleaning validation on the dexamethasone cream production line. The validation study involved evaluation of the cleaning procedures for the dexamethasone cream production line. Samples were collected at thirteen points involving the reactor, the colloidal mill, the industrial blender, the mixer and the packaging machine, for each of the batches. Samples were collected for study of the residue of the principle active ingredient, of detergent, and for microbiological analysis. Cleaning was shown to be within the stipulated parameters (acceptable level = 9.95 μg/mL) for: residues of active ingredient, TOC, pH, conductivity and microbiological contamination. It was thus concluded that the strategy adopted for cleaning validation was simple, swift, and efficient and capable of being applied to other kinds of pharmaceutical products.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Reconfiguração de sistemas de distribuição utilizando fluxo de potência ótimo e análise de sensibilidade

This paper presents a new approach for distribution system reconfiguration (DSR) based on optimum power flow (OPF) in which the branch statuses (open/close) are represented by continuous functions. In the proposed approach, all branches are initially considered closed and from the OPF results a heuristic technique is used to determine the next loop to be broken by opening one switch. Then the list of switches that are candidates to be opened is updated and the above process is repeated until all loops are broken, making the distribution system radial. The paper includes results and comparisons on test systems utilized in three classical papers published in the technical literature, as well as in a previous paper by the authors. Results obtained on a real large scale distribution system are also presented.Este artigo apresenta uma nova metodologia de Reconfiguração de Sistemas de Distribuição (RSD) baseada na utilização do Fluxo de Potência Ótimo (FPO) no qual o status das chaves (aberto/fechado) é representado através de funções contínuas. Na metodologia proposta, todas as chaves são consideradas inicialmente fechadas e a partir dos resultados fornecidos pelo FPO, utiliza-se uma técnica heurística para determinar o próximo laço a ser quebrado através da abertura de uma chave. A lista de chaves candidatas a abertura é atualizada e o processo descrito anteriormente é repetido até que todos os laços sejam quebrados, tornando o sistema radial. Este trabalho apresenta resultados e comparações utilizando-se sistemas publicados em três artigos técnicos clássicos encontrados na literatura e em um artigo prévio do autor. Resultados obtidos em sistemas reais de distribuição também serão apresentados

Avaliação do estado nutricional de agroecossistemas de café orgânico no estado de Minas Gerais.

A produção de café orgânico vem se constituindo uma tendência necessária e irreversível do agronegócio brasileiro. Essa atividade tem-se destacado como uma alternativa de renda para alguns cafeicultores, devido à crescente demanda mundial por alimentos mais saudáveis. Entretanto, grande parte das técnicas propostas pela agricultura orgânica está sendo aplicada empiricamente no cultivo de café, principalmente no Estado de Minas Gerais, maior região produtora de café do Brasil. Levando-se em consideração a baixa fertilidade natural dos solos dessa região cafeeira, bem como a elevada extração de nutrientes pelo cafeeiro, objetivou-se neste trabalho identificar possíveis fatores limitantes para a produção orgânica do cafeeiro, relacionados à fertilidade do solo e ao estado nutricional das plantas. Foram realizadas avaliações da fertilidade do solo e análise das folhas em vinte e uma lavouras orgânicas representativas do Estado de Minas Gerais. As amostras de solo foram analisadas para determinação do pH, acidez potencial e dos teores de P, K, Ca, Mg, S, Al e matéria orgânica. As amostras foliares foram analisadas para determinação dos teores de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn. Com base nos padrões de interpretação para cafeeiros convencionais propostos pela literatura, estabeleceram-se as freqüências com que os caracteres analisados foram inferiores aos critérios de interpretação da fertilidade do solo e estado nutricional das plantas. A análise dos dados foi realizada por estatística descritiva. Novos trabalhos nessa nova área são necessários, visando a uma melhor interpretação da análise foliar e da fertilidade do solo, quando se trabalha com café orgânico

Intragenic antimicrobial peptides (IAPs) from human proteins with potent antimicrobial and anti-inflammatory activity

Following the treads of our previous works on the unveiling of bioactive peptides encrypted in plant proteins from diverse species, the present manuscript reports the occurrence of four proof-of-concept intragenic antimicrobial peptides in human proteins, named Hs IAPs. These IAPs were prospected using the software Kamal, synthesized by solid phase chemistry, and had their interactions with model phospholipid vesicles investigated by differential scanning calorimetry and circular dichroism. Their antimicrobial activity against bacteria, yeasts and filamentous fungi was determined, along with their cytotoxicity towards erythrocytes. Our data demonstrates that Hs IAPs are capable to bind model membranes while attaining α-helical structure, and to inhibit the growth of microorganisms at concentrations as low as 1μM. Hs02, a novel sixteen residue long internal peptide (KWAVRIIRKFIKGFISNH2) derived from the unconventional myosin 1h protein, was further investigated in its capacity to inhibit lipopolysaccharide-induced release of TNF-α in murine macrophages. Hs02 presented potent anti-inflammatory activity, inhibiting the release of TNF-α in LPSprimed cells at the lowest assayed concentration, 0.1 μM. A three-dimensional solution structure of Hs02 bound to DPC micelles was determined by Nuclear Magnetic Resonance. Our work exemplifies how the human genome can be mined for molecules with biotechnological potential in human health and demonstrates that IAPs are actual alternatives to antimicrobial peptides as pharmaceutical agents or in their many other putative applications