TGF afterglows: A new radiation mechanism from thunderstorms

Thunderstorms are known to create terrestrial gamma ray flashes (TGFs) which are microsecond-long bursts created by runaway of thermal electrons from propagating lightning leaders, as well as gamma ray glows that possibly are created by relativistic runaway electron avalanches (RREA) that can last for minutes or more and are sometimes terminated by a discharge. In this work we predict a new intermediate thunderstorm radiation mechanism, which we call TGF afterglow, as it is caused by the capture of photonuclear neutrons produced by a TGF. TGF afterglows are milliseconds to seconds long; this duration is caused by the thermalization time of the intermediate neutrons. TGF afterglows indicate that the primary TGF has produced photons in the energy range of 10-30 MeV; they are nondirectional in contrast to the primary TGF. Gurevich et al. might have reported TGF afterglows in 2011

Preliminary study on the effect of fermented cheese whey on Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella Goldcoast populations inoculated onto fresh organic lettuce

Cheese whey fermented by an industrial starter consortium of lactic acid bacteria was evaluated for its antibacterial capacity to control a selection of pathogenic bacteria. For their relevance on outbreak reports related to vegetable consumption, this selection included Listeria monocytogenes, serotype 4b, Escherichia coli O157:H7, and Salmonella Goldcoast. Organically grown lettuce was inoculated with an inoculum level of *107 colonyforming unit (CFU)/mL and was left for about 1 h in a safety cabinet before washing with a perceptual solution of 75:25 (v/v) fermented whey in water, for 1 and 10 min. Cells of pathogens recovered were then counted and their number compared with that obtained for a similar treatment, but using a chlorine solution at 110 ppm. Results show that both treatments, either with chlorine or fermented whey, were able to significantly reduce ( p < 0.05) the number of bacteria, in a range of 1.15–2.00 and 1.59–2.34 CFU/g, respectively, regarding the bacteria tested. Results suggest that the use of fermented whey may be as effective as the solution of chlorine used in industrial processes in reducing the pathogens under study (best efficacy shown for Salmonella), with the advantage of avoiding health risks arising from the formation of carcinogenic toxic chlorine derinfo:eu-repo/semantics/publishedVersio

Activity of daptomycin- and vancomycin-loaded poly-epsilon-caprolactone microparticles against mature staphylococcal biofilms.

The aim of the present study was to develop novel daptomycin-loaded poly-epsilon-caprolactone (PCL) microparticles with enhanced antibiofilm activity against mature biofilms of clinically relevant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and polysaccharide intercellular adhesin-positive Staphylococcus epidermidis. Daptomycin was encapsulated into PCL microparticles by a double emulsion-solvent evaporation method. For comparison purposes, formulations containing vancomycin were also prepared. Particle morphology, size distribution, encapsulation efficiency, surface charge, thermal behavior, and in vitro release were assessed. All formulations exhibited a spherical morphology, micrometer size, and negative surface charge. From a very early time stage, the released concentrations of daptomycin and vancomycin were higher than the minimal inhibitory concentration and continued so up to 72 hours. Daptomycin presented a sustained release profile with increasing concentrations of the drug being released up to 72 hours, whereas the release of vancomycin stabilized at 24 hours. The antibacterial activity of the microparticles was assessed by isothermal microcalorimetry against planktonic and sessile MRSA and S. epidermidis. Regarding planktonic bacteria, daptomycin-loaded PCL microparticles presented the highest antibacterial activity against both strains. Isothermal microcalorimetry also revealed that lower concentrations of daptomycin-loaded microparticles were required to completely inhibit the recovery of mature MRSA and S. epidermidis biofilms. Further characterization of the effect of daptomycin-loaded PCL microparticles on mature biofilms was performed by fluorescence in situ hybridization. Fluorescence in situ hybridization showed an important reduction in MRSA biofilm, whereas S. epidermidis biofilms, although inhibited, were not eradicated. In addition, an important attachment of the microparticles to MRSA and S. epidermidis biofilms was observed. Finally, all formulations proved to be biocompatible with both ISO compliant L929 fibroblasts and human MG63 osteoblast-like cells

Sistema de oscilometria de impulso em pediatria: revisão de literatura

Introduction: impulse oscillometry (IOS) is considered a method of evaluation of respiratory mechanics, and being non-invasive, has been increasingly mentioned in the care and research of pediatric patients. Studies have considered the interest of determining reference values and check the IOS relationship with other methods of respiratory assessment.Objective: to present an update of the literature regarding the system, technical criteria and interpretation of data, as well as the relationship of the system with other methods of respiratory assessment and its clinical applicability.Method: literature review with consultation in the databases MEDLINE / PubMed and Ebsco, using the keywords: “impulse oscillometry”, "reference  values” and “child”. It was considered all material with information about the equipment, their indications and application as an evaluation tool in different clinical situations.Results: 45 documents were identified, (41 trials and 4 reviews), supplemented with 20 papers (1 guideline, 1 manual on equipment and 18 articles on the subject). This material was characterized by approaching the equipment, its parameters evaluation, performance technique and positioning of the patient during the examination, criteria for acceptability and reproducibility, and interpretation of the data obtained. There are several publications of this tool in the evaluation of respiratory mechanics disorders such as asthma and cystic fibrosis, and making on reference values in healthy children. Conclusion: IOS is a relatively new feature, whose indication  in pediatrics has been increasing, but still required investigations, both technical and clinical investigations.Introdução: a oscilometria de impulso (IOS) é considerado um método de avaliação da mecânica respiratória, e por ser não invasivo, vem sendo crescentemente indicado na assistência e investigação do paciente pediátrico. Estudos tem tido como interesse a determinação de valores de referência e a verificação da relação do IOS com outros métodos de avaliação respiratória. Objetivo: Apresentar uma atualização da literatura quanto ao sistema, critérios técnicos e interpretação de dados, bem como, a relação do sistema com outros métodos de avaliação respiratória e sua aplicabilidade clínica.Método: revisão bibliográfica com consulta nas bases de dados MEDLINE/PubMed e Ebsco, utilizando as palavras-chaves: “impulse oscillometry”, “reference values” e “child”. Considerou-se todo material com informações sobre o equipamento, suas indicações e aplicação como instrumento de avaliação em diferentes situações clínicas.Resultados: foram identificados 45 documentos, sendo 41 ensaios clínicos e 4 revisões, complementados com 20 trabalhos: 1 guideline, 1 manual sobre o equipamento e 18 artigos referentes ao tema. Esse material foi caracterizado por abordar o equipamento, seus parâmetros de avaliação, técnica de execução e posicionamento do paciente durante o exame, critérios de aceitabilidade e reprodutibilidade e interpretação dos dados obtidos. São várias as publicações dessa ferramenta na avaliação da mecânica respiratória de disfunções como asma e fibrose cística e geração de valores de referência em crianças saudáveis.Conclusão: o IOS é um recurso relativamente novo, cuja indicação em pediatriatem sido crescente, mas que ainda carece investigações, tanto técnicas quanto clínicas

Chemical Quality of Rainwater and Surface Runoff Water in the Proximity of the Abstractions That Supply the São Pedro do Sul Medical Spa (Portugal)

São Pedro do Sul medical spa provides health services using hot natural groundwater superiorly classified as natural mineral water. The main source of supply of that medical spa, has been over time, the Traditional Spring, which in recent decades has been systematically controlled, and shows spectacular constancy in its chemical quality, if there are no outside contaminations. Within the context presented, the detailed physical-chemical quality of rainwater and surface runoff water was studied, in the proximity of the Traditional Spring, as there is a potential for them to infiltrate at depth and evolve into the natural mineral water aquifer system. Thus, in the present chapter, after presenting the physical-chemical quality of the natural mineral water from the Traditional Spring, as well as some elements of the literature on the physical-chemical quality of rainwater, the methodology of work is followed, and then the results obtained from the physical-chemical composition of rainwater and surface run-off water are presented and discussed, comparing them with the quality of the water from the Traditional Spring. Finally, the main conclusions are presented, and some recommendations are made on research into potential sources of pollution, which justify the poor quality of the rainwater studied

Ferromagnetism and Canted Spin Phase in AlAs/GaMnAs Single Quantum Wells: Monte Carlo Simulation

The magnetic order resulting from a confinement-adapted Ruderman-Kittel-Kasuya-Yosida indirect exchange between magnetic moments in the metallic phase of a AlAs/Ga(1-x)Mn(x)As quantum well is studied by Monte Carlo simulation. This coupling mechanism involves magnetic moments and carriers (holes), both coming from the same Mn(2+) ions. It leads to a paramagnetic, a ferromagnetic, or a canted spin phase, depending on the carrier concentration, and on the magnetic layer width. It is shown that high transition temperatures may be obtained.Comment: 7 figure

Novel luminescent materials based on silica doped with an europium(III) complex of 2,6-dihydroxybenzoic acid: the crystal structure of [(nBu4N)2[Eu(2,6-Hdhb)(5)(H2O)(2)]

Novel luminescent materials were prepared by introducing a new Eu3+ complex of 2,6-dihydroxybenzoic acid (2,6-H2dhb) into a silica gel made by the sol–gel method. The crystal structure of the resulting complex [nBu4N]2[Eu(2,6-Hdhb)5(H2O)2] was determined using single-crystal X-ray diffraction. The compound was further characterised using FTIR, FT-Raman and elemental analysis. Photoluminescence measurements were performed for the isolated Eu(III) 2,6-dihydroxybenzoate complex and also for the related silica composite material

A mathematical analysis of the evolution of perturbations in a modified Chaplygin gas model

One approach in modern cosmology consists in supposing that dark matter and dark energy are different manifestations of a single `quartessential' fluid. Following such idea, this work presents a study of the evolution of perturbations of density in a flat cosmological model with a modified Chaplygin gas acting as a single component. Our goal is to obtain properties of the model which can be used to distinguish it from another cosmological models which have the same solutions for the general evolution of the scale factor of the universe, without the construction of the power spectrum. Our analytical results, which alone can be used to uniquely characterize the specific model studied in our work, show that the evolution of the density contrast can be seen, at least in one particular case, as composed by a spheroidal wave function. We also present a numerical analysis which clearly indicates as one interesting feature of the model the appearence of peaks in the evolution of the density constrast.Comment: 21 pages, accepted for publication in General Relativity and Gravitatio