493 research outputs found
Differential antifungal activity of human and cryptococcal melanins with structural discrepancies
Indexación: Scopus.Melanin is a pigment found in all biological kingdoms, and plays a key role in protection against ultraviolet radiation, oxidizing agents, and ionizing radiation damage. Melanin exerts an antimicrobial activity against bacteria, fungi, and parasites. We demonstrated an antifungal activity of synthetic and human melanin against Candida sp. The members of the Cryptococcus neoformans and C. gattii species complexes are capsulated yeasts, which cause cryptococcosis. For both species melanin is an important virulence factor. To evaluate if cryptococcal and human melanins have antifungal activity against Cryptococcus species they both were assayed for their antifungal properties and physico-chemical characters. Melanin extracts from human hair and different strains of C. neoformans (n = 4) and C. gattii (n = 4) were investigated. The following minimum inhibitory concentrations were found for different melanins against C. neoformans and C. gattii were (average/range): 13.7/(7.8-15.6) and 19.5/(15.6-31.2) μg/mL, respectively, for human melanin; 273.4/(125- > 500) and 367.2/(125.5- > 500) μg/mL for C. neoformans melanin and 125/(62.5-250) and 156.2/(62-250) μg/mL for C. gattii melanin. Using Scanning Electron Microscopy we observed that human melanin showed a compact conformation and cryptococcal melanins exposed an amorphous conformation. Infrared spectroscopy (FTIR) showed some differences in the signals related to C-C bonds of the aromatic ring of the melanin monomers. High Performance Liquid Chromatography established differences in the chromatograms of fungal melanins extracts in comparison with human and synthetic melanin, particularly in the retention time of the main compound of fungal melanin extracts and also in the presence of minor unknown compounds. On the other hand, MALDI-TOF-MS analysis showed slight differences in the spectra, specifically the presence of a minor intensity ion in synthetic and human melanin, as well as in some fungal melanin extracts. We conclude that human melanin is more active than the two fungal melanins against Cryptococcus. Although some physico-chemical differences were found, they do not explain the differences in the antifungal activity against Cryptococcus of human and cryptococcal melanins. More detailed studies on the structure should be considered to associate structure and antifungal activity.https://www.frontiersin.org/articles/10.3389/fmicb.2017.01292/ful
Quark mass dependence of scattering in isospin 0, 1, and 2 from lattice QCD
Using lattice QCD we extract scattering amplitudes with
isospin--0,1,2 in low partial-waves at two values of the light quark mass
corresponding to and MeV. We confirm expectations of
weak repulsion in isospin--2, and the presence of a narrow resonance in
isospin--1, and study the pion mass dependence of these channels. In isospin--0
we find that the two pion masses considered straddle the point at which the
transitions from being a stable bound-state to being either a virtual
bound-state or a subthreshold resonance. We discuss the ability of lattice
calculations like these to precisely determine the pole location when
it is a resonance, and propose an approach in which the full complement of
amplitudes computed in this paper can be used simultaneously to provide more
constraint.Comment: 18 pages, 17 figures, 1 table, corresponds to version published in
PR
Laser tweezers for atomic solitons
We describe a controllable and precise laser tweezers for Bose-Einstein
condensates of ultracold atomic gases. In our configuration, a laser beam is
used to locally modify the sign of the scattering length in the vicinity of a
trapped BEC. The induced attractive interactions between atoms allow to extract
and transport a controllable number of atoms. We analyze, through numerical
simulations, the number of emitted atoms as a function of the width and
intensity of the outcoupling beam. We also study different configurations of
our system, as the use of moving beams. The main advantage of using the control
laser beam to modify the nonlinear interactions in comparison to the usual way
of inducing optical forces, i.e. through linear trapping potentials, is to
improve the controllability of the outcoupled solitary wave-packet, which opens
new possibilities for engineering macroscopic quantum states.Comment: 6 pages, 7 figure
Efecto sobre el rendimiento de la infección de la piricularia (Pyricularia oryzae Cav.) en el cuello de la panícula de arroz (Oryza sativa L.).
Arroz-Oryza sativaMaestría en CienciasMaestrí
Seroprevalencia del virus de la leucosis viral bovina en animales con trastornos reproductivos de Montería
Objetivo. Determinar la seroprevalencia de Leucosis Viral Bovina (LVB) en animales con trastornos reproductivos. Materiales y métodos. Se recolectaron 137 muestras de sangre de hembras con antecedentes de infertilidad, pertenecientes a 28 fincas distribuidas en el municipio de Montería; adicionalmente, se obtuvieron muestras al azar de 26 toros pertenecientes a las mismas fincas que fueron analizadas para anticuerpos contra LVB. La técnica serológica empleada fue la prueba de ELISA. Se realizó un análisis descriptivo tabulando la información con datos de seropositividad y seronegatividad obtenidos de cada animal; los resultados se interpretaron de acuerdo a las variables: raza, edad, sexo, zona, tipo de explotación y evento o problema reproductivo detectado. Para determinar la asociación entre seropositividad y cada una de las variables se utilizó la prueba de χ 2 . Resultados. Las pruebas arrojaron una seroprevalencia del 21% para LVB. No se encontraron diferencias significativas de prevalencia asociadas a las variables raza, edad o estado reproductivo de los animales (p≥0.05), pero si entre la presencia de anticuerpos contra LVB y las variables zona, tipo de explotación y sexo. Conclusiones. Se demuestra la circulación del virus de la LVB en Montería, (Colombia). Se confirma la importancia de implementar un programa de control y prevención de la diseminación de la infección, con el fin de evitar las pérdidas económicas asociadas, y dentro de lo posible, la eliminación de los especímenes seropositivos para lograr la erradicación de la infección en esta zona del paí
How does time spent working in custody influence health and fitness characteristics of law enforcement officers?
This study investigated the influence of time spent working in custody on the health and fitness of law enforcement officers (LEOs). Retrospective analysis was conducted on data from 48 male and 12 female LEOs, divided into groups based upon time spent working custody: LEO ≤ 24 (≤24 months; n = 15); LEO 2547 (25–47 months; n = 24); and LEO 48+ (≥48 months; n = 21). The following were measured: body mass index (BMI); fat mass percentage; waist-to-hip ratio (WHR); resting heart rate (RHR); blood pressure; grip strength; sit-and-reach; push-ups; sit-ups; and YMCA step test recovery heart rate (HR). A univariate ANCOVA (controlling for sex and age) with Bonferroni post hoc determined significant between-group differences. Select assessments were compared to normative data. The LEO 48+ group completed fewer sit-ups than the LEO 2547 group (p = 0.006); there were no other significant between-group differences. Forty-nine LEOs were overweight or obese according to BMI; 52 were fatter than average or above; 27 had a WHR that increased cardiovascular disease risk. Forty-three LEOs had very poor RHR; 52 had elevated blood pressure. Forty-eight LEOs had average-to-very poor step test recovery HR. Irrespective of time spent working in custody, personnel should be physically active to maintain health and fitness and, where possible, engage in formal strength training and conditioning
Analysis of an atom laser based on the spatial control of the scattering length
In this paper we analyze atom lasers based on the spatial modulation of the
scattering length of a Bose-Einstein Condensate. We demonstrate, through
numerical simulations and approximate analytical methods, the controllable
emission of matter-wave bursts and study the dependence of the process on the
spatial dependence of the scattering length along the axis of emission. We also
study the role of an additional modulation of the scattering length in time.Comment: Submitted to Phys. Rev.
Teor de Ca, Mg e S em alface-americana em função da aplicação de nitrogênio e potássio em adubação de cobertura, nas condições de inverno.
O presente trabalho foi realizado com o objetivo de avaliar os efeitos da adubação com N e K em cobertura sobre o teor de Ca, Mg e S em alface-americana (Lactuca sativa L.), cv. Raider, nas condições de inverno de Três Pontas, MG.Edição dos resumos expandidos do 45. Congresso Brasileiro de Olericultura; 15. Congresso Brasileiro de Floricultura e Plantas Ornamentais; 2. Congresso Brasileiro de Cultura de Tecidos de Plantas, Fortaleza, ago. 2005. 1 CD-ROM
Imersão de bulbilhos-semente de alho proveniente de cultura de meristemas em solução com Booster.
O trabalho foi realizado com o objetivo de determinar a influência da imersão de bulbilhos em solução com o produto comercial Booster(5) na produtividade da cultura de alho vernalizado cv. Roxo Pérola de Caçador proveniente de cultura de meristemas. O experimento foi conduzido entre os meses de maio a novembro de 2005. Utilizou-se o delineamento experimental de blocos casualizados, onde os tratamentos foram constituídos por quatro doses do produto (500,1000,1500 e 2000 mU 100L de água ha-1) e um tratamento testemunha, com quatro repetições. As características avaliadas foram: produtividade total de bulbos, produtividade comercial de bulbos (bulbos com diâmetro acima de 42 mm) e peso médio de bulbos comerciais. Para as três características avaliadas não foi observada diferença significativa entre os tratamentos, portanto, conclui-se que, nas condições em que foi realizado o experimento, torna-se desnecessária a realização do tratamento pré-plantio de bulbilhos de alho em solução contendo tais micronutrientes.Suplemento. Edição dos Resumos expandidos do 46. Congresso Brasileiro de Olericultura, Goiânia, jul. 2006
Efecto sobre el rendimiento de la infección de la piricularia (Pyricularia oryzae Cav.) en el cuello de la panícula del arroz (Oriza sativa L.).
Arroz-Oryza sativ
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