911 research outputs found
Light induced electron spin resonance in a-Ge:H
We report the observation of light-induced electron spin resonance (LESR) in amorphous hydrogenated germanium. Two new lines with zero crossings near g=2.01 and g=2.03 were detected and ascribed to electrons and holes in the conduction- and valence-band-tail states, respectively. The ratio between the LESR spin densities of both lines is approximately one, suggesting the absence of spin pairing, charge defect creation, or LESR of dangling bonds. The growth and decay spectra exhibit dispersive behavior with a dispersion parameter âŒ0.5. The decay spectrum is best fit assuming bimolecular recombination. The LESR spin density depends weakly on the photogeneration rate as a sublinear power law
Co-delivery of buparvaquone and polymyxin B in a nanostructured lipid carrier for leishmaniasis treatment
Angular dependence of the bulk nucleation field Hc2 of aligned MgB2 crystallites
Studies on the new MgB2 superconductor, with a critical temperature Tc ~ 39
K, have evidenced its potential for applications although intense magnetic
relaxation effects limit the critical current density, Jc, at high magnetic
fields. This means that effective pinning centers must be added into the
material microstructure, in order to halt dissipative flux movements.
Concerning the basic microscopic mechanism to explain the superconductivity in
MgB2, several experimental and theoretical works have pointed to the relevance
of a phonon-mediated interaction, in the framework of the BCS theory. Questions
have been raised about the relevant phonon modes, and the gap and Fermi surface
anisotropies, in an effort to interpret spectroscopic and thermal data that
give values between 2.4 and 4.5 for the gap energy ratio. Preliminary results
on the anisotropy of Hc2 have shown a ratio, between the in-plane and
perpendicular directions, around 1.7 for aligned MgB2 crystallites and 1.8 for
epitaxial thin films. Here we show a study on the angular dependence of Hc2
pointing to a Fermi velocity anisotropy around 2.5. This anisotropy certainly
implies the use of texturization techniques to optimize Jc in MgB2 wires and
other polycrystalline components.Comment: 10 pages + 4 Figs.; Revised version accepted in Phys. Rev.
Magnetic Field Dependence Of The Curie-weiss Paramagnetism In Crv Alloys
The determination of the magnetic properties of antiferromagnetic Cr alloys requires careful consideration of the influence of the applied magnetic field. In this work we show that alloys of Cr-x at. % V present a Curie-Weiss paramagnetism above the NĂ©el temperature, which is suppressed by a characteristic field HL. Samples with x=0.1, 0.2, and 0.4 were investigated through measurements of the magnetic susceptibility as a function of temperature, for different values of the magnetic field. A magnetic phase diagram showing the characteristic line HL vs x at. % V is proposed. © 1997 American Institute of Physics.818 PART 2A42094211Suzuki, T., Takaki, H., (1964) J. Phys. Soc. Jpn., 19, p. 1241Suzuki, T., (1966) J. Phys. Soc. Jpn., 21, p. 442Aidun, R., Arajs, S., Moyer, C.A., (1985) Phys. Status Solidi B, 128, p. 133Hill, P., Ali, N., De Oliviera, A.J.A., Ortiz, W.A., De Camargo, P.C., Fawcett, E., (1994) J. Phys. Condens. Matter., 6, p. 1761De Oliveira, A.J.A., Otriz, W.A., De Camargo, P.C., Galkin, V.Yu., (1996) J. Magn. Magn. Mater., 152, p. 86De Oliveira, A.J.A., De Lima, O.F., De Camargo, P.C., Ortiz, W.A., Fawcett, E., (1996) J. Phys. Condens. Matter., 8, pp. L403Benediktsson, G., Hedman, L., Aström, H.U., Rao, K.V., (1982) J. Phys. F, 12, p. 1439Booth, J.G., (1964) Phys. Status Solidi, 7 K, p. 157Bender, D., MĂŒller, J., (1970) Phys. Kondens. Mater., 10, p. 342Buzdin, A.I., Men'shov, V.N., Tugushev, V.V., (1986) Zh. Eksp. Teor. Fiz., 91, p. 2204(1986) Sov. Phys. JETP, 64. , Engl. TranslTugushev, V.V., (1992) Modulated and Localized Structures of the Spin-Density Wave in Itinerant Antiferromagnets in Electronic Phase Transitions, p. 237. , edited by W. Hanke and Yu. Koapev Elsevier, AmsterdamDe Oliveira, A.J.A., De Lima, O.F., Ortiz, W.A., De Camargo, P.C., (1995) Solid State Commun., 96, p. 383De Oliveira, A.J.A., (1996), PhD. thesis, Universidade Federal de SĂŁo Carlo
Rapid and reliable identification of intact Candida clinical isolates using MALDI-TOF ICMS
The significant increase in the frequency of candidiasis wide world has promoted the study and development of fast and reliable
techniques aimed at the replacement of traditional methods used for identification and typing of Candida clinical isolates.
Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight lntact Cell Mass Spectrometry (MALDI-TOF ICMS) has been
applied as current method for Candida identification in clinical laboratories. This method is reported as suitable fur routine
identification in clinical laboratories and fast and reliable for identification of pathogenic yeasts. The main aim of this study was
to compare MALDI-TOF ICMS performance with the classical phenotypic approach and molecular analyses to identify Candida
species from clinical cases. Forty clinical Candida isolates preserved in URM Culture Collection fur I to 52 years were
identified by morphological and biochemical analysis as Candida albicans (20), C. krusei (05), C. parapsilosis (11) and C.
tropicalis (04). These identifications were compared with the discriminative capability of the new phenotypic approaches using
MALDI-TOF ICMS. MALDI-TOF ICMS data demonstrated 15% discordance when compared with morphological and
biochemical analyses. The discordant isolates were analysed by ITS sequencing which corroborated the MALDI-TOF ICMS
identifications. Five Candida krusei isolates were renamed Issatchenkia orientalis by MALDI-TOF ICMS SARAMISTM
database, which is their teleomorphic name. ln conclusion MALDI-TOF ICMS represents a rapid and reliable method of
identifying Candida and also presents clear benefits when compared with the performance of existing daily routine methods
applied at health centres and hospitals. Research leading to these results received funding from the European Community's
Seventh Framework Program (FP7, 2007-2013), Research lnfrastructures Action, under grant agreement No. FP7-228310
(EMbaRC project). Thanks are also due to Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES, Brazil) for
funding support.European Community's Seventh Fmmework Progmm (FP7, 2007-2013), Research lnfrastructures Action, under gmnt agreement No. FP7-228310
(EMbaRC project), Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES, Brazil
Minimal model for aeolian sand dunes
We present a minimal model for the formation and migration of aeolian sand
dunes. It combines a perturbative description of the turbulent wind velocity
field above the dune with a continuum saltation model that allows for
saturation transients in the sand flux. The latter are shown to provide the
characteristic length scale. The model can explain the origin of important
features of dunes, such as the formation of a slip face, the broken scale
invariance, and the existence of a minimum dune size. It also predicts the
longitudinal shape and aspect ratio of dunes and heaps, their migration
velocity and shape relaxation dynamics. Although the minimal model employs
non-local expressions for the wind shear stress as well as for the sand flux,
it is simple enough to serve as a very efficient tool for analytical and
numerical investigations and to open up the way to simulations of large scale
desert topographies.Comment: 19 pages, 22 figure
Species-specific responses of planktivorous fish to the introduction of a new piscivore: implications for prey fitness
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75539/1/j.1365-2427.2007.01810.x.pd
Fungal Infections in Neonatal Intensive Care
Neonates represent a unique and highly vulnerable patient population. Advances in medical technology have improved the survival and quality of life of newborns, particularly those with extreme prematurity or with congenital defects. Furthermore, immunologic immaturity and altered cutaneous barriers play some role in the vulnerability of neonates to nosocomial infections. In this context, the incidence of invasive fungal infections has increased significantly worldwide, representing an important infective complication in patients hospitalized in intensive care units. Invasive fungal infections in Neonatal Intensive Care Unit (NICUs) show high mortality; being species of Candida, the most isolates etiologic agents. The better prognosis of the patient is associated with the early diagnosis and fast treatment. However, guidelines to facilitate the optimal therapy choice for the treatment of neonatal fungal disease do not exist. The current antifungal agents that are available to treat fungemia among newborns and children are based on clinical trials in adults, since there are few comparative studies of antifungal agents in infants. The most commonly used drugs for the treatment of invasive fungal infections in neonates are classified in four different classes: polyene, azoles, analogs of pyrimidines and echinocandins
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