On the nature of the spin-polarized hole states in a quasi-two-dimensional GaMnAs ferromagnetic layer

A self-consistent calculation of the density of states and the spectral density function is performed in a two-dimensional spin-polarized hole system based on a multiple-scattering approximation. Using parameters corresponding to GaMnAs thin layers, a wide range of Mn concentrations and hole densities have been explored to understand the nature, localized or extended, of the spin-polarized holes at the Fermi level for several values of the average magnetization of the Mn ystem. We show that, for a certain interval of Mn and hole densities, an increase on the magnetic order of the Mn ions come together with a change of the nature of the states at the Fermi level. This fact provides a delocalization of spin-polarized extended states anti-aligned to the average Mn magnetization, and a higher spin-polarization of the hole gas. These results are consistent with the occurrence of ferromagnetism with relatively high transition temperatures observed in some thin film samples and multilayered structures of this material.Comment: 3 page

Oxygenated monoterpenes-rich volatile oils as potential antifungal agents for dermatophytes

Essential oils (EOs) extracted from Lavandula luisieri and Cymbopogon citratus were tested for their antifungal activity against ten clinical isolates of dermatophytes isolated from cases of tinea pedis. Inhibition of conidial germination and antifungal drug/EO combination assay were tested on two ATCC reference strains of Trichophyton rubrum and Trichophyton mentagrophytes. EOs were characterised by high amount of oxygenated monoterpenes in their composition. Strong antifungal activity was observed for the majority of clinical strains, and fungicidal activity was demonstrated. Positive interaction between L. luisieri EO combined with terbinafine was observed against terbinafine-resistant strain (Tr ATCC MYA-4438). Significative reduction of the germination was observed above 100 g mL1. Both oils were safe to macrophage mammalian cells at tested concentration. This study describes the antifungal activity of L. luisieri and C. citratus EOs against dermatophytes, which could be useful in designing new formulations for topical treatments.This work was supported by Portuguese Foundation for Science and Technology (FCT) [grant number PEST-C/FIS/UI607/2013], [grant number UID/BIO/04469/2013], [grant number PEst-OE/EQB/LA0023/2013] and European Community fund FEDER [grant number FCOMP-01-0124-FEDER-007025], [grant number RECI project: FCOMP-01-0124-FEDER-027462].The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Nicolina Dias acknowledges the project “Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB”, Ref. FCOMP-01-0124-FEDER-027462

Epidemia de Zucchini lethal chlorosis virus (ZLCV) na cultura da melancia no Brasil Central.

As viroses estão entre as doenças que mais afetam as cucurbitáceas em todo o mundo, resultando em queda de produtividade e podendo limitar a produção. No ano de 2013, sintomas de mosaico, deformação foliar, paralisação do crescimento da planta, com reflexos significativos na produção foram observados em lavouras de melancia de municípios do Estado de Goiás.Resum

Toenail onychomycosis in a Portuguese geriatric population

Onychomycosis is a common fungal infection of the nail but few data of mycological features in geriatric Portuguese population are yet available. The aim of this study was to perform a mycological examination and characterization of fungal nail pattern of a geriatric population from the north of Portugal clinically suspected of onychomycosis. A total of 108 patients attending the Podology Service in the Centro Hospitalar do Alto Ave (Portugal) from October 2007 to January 2009 were enrolled. All were suspected of having onychomycosis by the abnormal appearance of their nails. From these, 59.3% were diabetic. Distal and lateral subungual onychomycosis was the more common clinical pattern followed by total dystrophic onychomycosis. In 21.3% cases, every nail in both feet had an abnormal appearance. In 86%, the hallux was involved in at least one foot. Fifty samples were culture positive, and fifty-four isolates were reported regardless of the questionable pathogenicity of the infectious agent. In three cases, clinical feature of the nail, direct microscopy, and culture were consistent with Scopulariopsis infection. Fusarium spp. were identified in three cases; however, only one isolate was preceded by the observation of branching septate filaments by direct microscopy. No mixed infections with dermatophytes were reported. Trichophyton rubrum was the dermatophyte most frequently isolated (83.3%) followed by Trichophyton interdigitale. In Portugal, onychomycosis is still viewed by general population as a cosmetic condition. Health risk is enhanced in geriatrics that only perceived the severity of their condition when experiencing further foot complications that include bacterial infection and pain

A semiquantitative approach to the impurity-band-related transport properties of GaMnAs nanolayers

We investigate the spin-polarized transport of GaMnAs nanolayers in which a ferromagnetic order exists below a certain transition temperature. Our calculation for the self-averaged resistivity takes into account the existence of an impurity band determining the extended ("metallic" transport) or localized (hopping by thermal excitation) nature of the states at and near the Fermi level. Magnetic order and resistivity are inter-related due to the influence of the spin polarization of the impurity band and the effect of the Zeeman splitting on the mobility edge. We obtain, for a given range of Mn concentration and carrier density, a "metallic" behavior in which the transport by extended carriers dominates at low temperature, and is dominated by the thermally excited localized carriers near and above the transition temperature. This gives rise to a conspicuous hump of the resistivity which has been experimentally observed and brings light onto the relationship between transport and magnetic properties of this material

Silver nanoparticles as an antimicrobial agent of Tricophyton rubrum

Resistance to antimicrobial agents, such as amphotericin B, fluconazole, itraconazole, and voriconazole, by pathogenic bacteria and fungi has been increasing at an alarming rate and has become a serious problem. Microorganisms, such as bacteria, moulds, yeasts, and viruses are often pathogenic to humans. There is a pressing need to search for new antimicrobial agents. Amongst inorganic antimicrobial agents, silver has been employed most widely since ancient times to fight infections. The antimicrobial activities of silver, silver ions, and silver compounds are well known Fungi can be employed for biosynthesis of nanoparticles hence avoiding the use of hazardous chemicals for synthesis. However, the effects of mycological synthesized silver nanoparticles against fungal dermatophytes are not well understod. In this work were used inorganic and biogenic routes for the synthesis of silver nanoparticles. In the biogenic route, extracts from Aspergillus oryzae and Penicillium chrysogenum were used. In the inorganic route glucose was used as the reducing agent and polyvinylpyrrolidone as the stabilizer. The nanoparticles were characterized by various techniques. Biogenic nanoparticles from A. ozyzae and P. chrysogenum showed an average size from 19-51 nm to 51-85 nm, respectively. Nanoparticles synthesized by inorganic route had a mean size of 74 nm as determined by Dynamic Light Scattering. The antimicrobial potential activity was tested against strains of Tricophyton rubrum and the silver nanoparticles from P. chrysogenum had antimicrobial effects against T. rubrum strains. The synthesis parameters in future studies should be studied to take full advantage of the potentail for filamentous fungi to synthesise silver nanoparticles

Análise comparativa de resultados de espetrometria gama portátil em afloramentos rochosos

São comparadas estimativas de elementos obtidas por espetrometria gama portátil em afloramentos de rochas metamórficas e ígneas, assim como medições de campo e análises laboratoriais para uma das rochas ígneas consideradas, tendo em vista contribuir para a discussão da utilidade da espetrometria portátil técnica na avaliação dos ma teriaisEste trabalho foi desenvolvido no âmbito das atividades do Lab2PT- Laboratório de Paisagens, Património e Território (AUR/04509) financiado pela FCT através de fundos nacionais e quando aplicável do cofinanciamento do FEDER, no âmbito dos novos acordos de parceria PT2020 e COMPETE 2020 – POCI-01-0145-FEDER-007528.info:eu-repo/semantics/publishedVersio

Geological materials and external gamma radiation

A diretiva 2013/59/EURATOM pretende fixar normas de segurança para a exposição a radiações ionizantes (como a radiação gama), incluindo a regulação da comercialização de materiais de construção, podendo ter efeitos restritivos no aproveitamento económico destes. Esta diretiva define um limite para a contribuição dos materiais de construção (incluindo os materiais geológicos) para a radiação gama externa (contribuição avaliada por um índice baseado em estimativas das concentrações de átomos que emitem radiação gama). São revistos os fatores que influenciam a contribuição dos materiais geológicos para a radiação gama externa de espaços interiores, em termos gerais e no caso de estudo de um granito alterado. Os resultados são confrontados com os critérios da diretiva referida, concluindo-se que a mesma poderá ser excessivamente restritiva para os usos atualmente mais comuns da pedra natural (utilização parcial de revestimentos finos). Em situações envolvendo uma maior aplicação de material (e.g. algumas construções históricas), a perigosidade de atingir níveis de radiação acima do valor de referência indicado na diretiva é maior mas é necessário considerar fatores como o tempo de exposição e o uso de revestimentos com nível de radiação inferior ao do material considerado (com implicações em termos de valorização de materiais e opções construtivas).The directive 2013/59 / EURATOM intends to establish safety standards for exposure to ionizing radiation (such as gamma radiation), including the regulation of building materials trade (it could, hence, have restrictive effects on the economic exploitation of this materials). This directive sets a limit on the contribution of building materials (including geological materials) for external gamma radiation (contribution assessed by an index based on quantitative estimations of atoms that emit gamma radiation). The factors that influence the contribution of geological materials for external gamma radiation in interior spaces are reviewed for the general case and for the case of a weathered granite from Braga. Results are compared with the criteria of the considered directive, concluding that this directive could be excessively restrictive for the currently most common uses of natural stone (partial cladding). In situations involving the use of larger amounts of stone (e.g. some historical buildings), the hazard of reaching a radiation level above the reference level proposed in the directive are higher but one needs to consider factors such as exposure time and the use of coatings with radiation level lower than that of the considered material (this could have implications in terms of materials valorisation and constructive options).Este trabalho foi desenvolvido no âmbito das atividades do Lab2PT- Laboratório de Paisagens, Património e Território (AUR/04509) financiado pela FCT através de fundos nacionais e quando aplicável do cofinanciamento do FEDER, no âmbito dos novos acordos de parceria PT2020 e COMPETE 2020 – POCI-01-0145-FEDER-007528. O grupo de investigação CULXEO de que faz parte J. Sanjurjo-Sánchez é financiado pela Xunta de Galicia através do programa “Consolidación e estructuración de unidades de investigación competitivas — Grupo de potencial de crecimiento” (GPC2015/024).info:eu-repo/semantics/publishedVersio