457 research outputs found
Complement factor h-antibody-associated hemolytic uremic syndrome: pathogenesis, clinical presentation, and treatment.
The presence of circulating autoantibodies, primarily to complement factor H antibodies (CFH-Abs) in plasma characterizes the autoimmune form of atypical hemolytic uremic syndrome (aHUS). This acquired form of aHUS defines a distinct subgroup of aHUS patients, which requires diagnostic and treatment approaches in part different from those of the genetically defined forms. The mechanisms leading to CFH-Ab production and disease onset are not completely understood, but CFH-Ab HUS seems to be secondary to a combination of genetic predisposition and environmental factors. Early diagnosis of this specific aHUS entity is important, as prompt induction of plasma exchange and concomitant immunosuppression leads to a favorable outcome. Nevertheless, information on clinical features and outcome in children is limited. Here, we review the literature on the biological and clinical features of CFH-Ab HUS and discuss therapeutic options
Magnetic and Transport Properties of Fe-Ag granular multilayers
Results of magnetization, magnetotransport and Mossbauer spectroscopy
measurements of sequentially evaporated Fe-Ag granular composites are
presented. The strong magnetic scattering of the conduction electrons is
reflected in the sublinear temperature dependence of the resistance and in the
large negative magnetoresistance. The simultaneous analysis of the magnetic
properties and the transport behavior suggests a bimodal grain size
distribution. A detailed quantitative description of the unusual features
observed in the transport properties is given
Magnetic induction mapping of magnetite chains in magnetotactic bacteria at room temperature and close to the Verwey transition using electron holography
Off-axis electron holography in the transmission electron microscope is used to record magnetic induction maps of closely spaced magnetite crystals in magnetotactic bacteria at room temperature and after cooling the sample using liquid nitrogen. The magnetic microstructure is related to the morphology and crystallography of the particles, and to interparticle interactions. At room temperature, the magnetic signal is dominated by interactions and shape anisotropy, with highly parallel and straight field lines following the axis of each chain of crystals closely. In contrast, at low temperature the magnetic induction undulates along the length of the chain. This behaviour may result from a competition between interparticle interactions and an easy axis of magnetisation that is no longer parallel to the chain axis. The quantitative nature of electron holography also allows the change in magnetisation in the crystals with temperature to be measured
Utilization of furfola 4. : Production of Pyrrole from Furfurol by means of a Contact Process in the Vapour Phase
Quantum rings with time dependent spin-orbit coupling: Rabi oscillations, spintronic Schrodinger-cat states, and conductance properties
The strength of the (Rashba-type) spin-orbit coupling in mesoscopic
semiconductor rings can be tuned with external gate voltages. Here we consider
the case of a periodically changing spin-orbit interaction strength as induced
by sinusoidal voltages. In a closed one dimensional quantum ring with weak
spin-orbit coupling, Rabi oscillations are shown to appear. We find that the
time evolution of initially localized wave packets exhibits a series of
collapse and revival phenomena. Partial revivals -- that are typical in
nonlinear systems -- are shown to correspond to superpositions of states
localized at different spatial positions along the ring. These "spintronic
Schrodinger-cat sates" appear periodically, and similarly to their counterparts
in other physical systems, they are found to be sensitive to environment
induced disturbances. The time dependent spin transport problem, when leads are
attached to the ring, is also solved. We show that the "sideband currents"
induced by the oscillating spin-orbit interaction strength can become the
dominant output channel, even in the presence of moderate thermal fluctuations
and random scattering events.Comment: 11 pages, 9 figures, submitted to PR
“CLOCK IN THE ROCK” – IN-SITU C-14 ROCK SURFACE EXPOSURE DATING APPLICATIONS
Cosmic rays interact not only with the atmosphere, but also with material at the surface of the Earth. Thus C-14 can be produced directly in a rock surface by the effect of cosmic-ray neutron effects. The goal of the research is to develop the capability of the Hertelendi Laboratory for Environmental Sciences (HEKAL) in the field of cosmogenic radionuclides produced in situ by the action of cosmic radiation. Our aim is to construct a small line for the extraction of cosmogenic C-14 from quartz, making a system compatible with the online capabilities of the new MICADAS accelerator mass spectrometer (AMS) at HEKAL in Debrecen. We have tested the chemical blank level, cross contamination effect and reproducibility of MICADAS gas ion source application in in-situ rock surface exposure dating
Microbiology and atmospheric processes: Biological, physical and chemical characterization of aerosol particles
The interest in bioaerosols has traditionally been linked to health hazards for humans, animals and plants. However, several components of bioaerosols exhibit physical properties of great significance for cloud processes, such as ice nucleation and cloud condensation. To gain a better understanding of their influence on climate, it is therefore important to determine the composition, concentration, seasonal fluctuation, regional diversity and evolution of bioaerosols. In this paper, we will review briefly the existing techniques for detection, quantification, physical and chemical analysis of biological particles, attempting to bridge physical, chemical and biological methods for analysis of biological particles and integrate them with aerosol sampling techniques. We will also explore some emerging spectroscopy techniques for bulk and single-particle analysis that have potential for in-situ physical and chemical analysis. Lastly, we will outline open questions and further desired capabilities (e. g., in-situ, sensitive, both broad and selective, on-line, time-resolved, rapid, versatile, cost-effective techniques) required prior to comprehensive understanding of chemical and physical characterization of bioaerosols
Nanoscale spin-polarization in dilute magnetic semiconductor (In,Mn)Sb
Results of point contact Andreev reflection (PCAR) experiments on (In,Mn)Sb
are presented and analyzed in terms of current models of charge conversion at a
superconductor-ferromagnet interface. We investigate the influence of surface
transparency, and study the crossover from ballistic to diffusive transport
regime as contact size is varied. Application of a Nb tip to a (In,Mn)Sb sample
with Curie temperature Tc of 5.4 K allowed the determination of
spin-polarization when the ferromagnetic phase transition temperature is
crossed. We find a striking difference between the temperature dependence of
the local spin polarization and of the macroscopic magnetization, and
demonstrate that nanoscale clusters with magnetization close to the saturated
value are present even well above the magnetic phase transition temperature.Comment: 4 page
Anomalous Hall effect in (In,Mn)Sb dilute magnetic semiconductor
High magnetic field study of Hall resistivity in the ferromagnetic phase of
(In,Mn)Sb allows one to separate its normal and anomalous components. We show
that the anomalous Hall term is not proportional to the magnetization, and that
it even changes sign as a function of magnetic field. We also show that the
application of pressure modifies the scattering process, but does not influence
the Hall effect. These observations suggest that the anomalous Hall effect in
(In,Mn)Sb is an intrinsic property and support the application of the Berry
phase theory for (III,Mn)V semiconductors. We propose a phenomenological
description of the anomalous Hall conductivity, based on a field-dependent
relative shift of the heavy- and light-hole valence bands and the split-off
band
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