1,298 research outputs found
Two-Body Random Ensembles: From Nuclear Spectra to Random Polynomials
The two-body random ensemble (TBRE) for a many-body bosonic theory is mapped
to a problem of random polynomials on the unit interval. In this way one can
understand the predominance of 0+ ground states, and analytic expressions can
be derived for distributions of lowest eigenvalues, energy gaps, density of
states and so forth. Recently studied nuclear spectroscopic properties are
addressed.Comment: 8 pages, 4 figures. To appear in Physical Review Letter
Guillain-Barré syndrome:multifactorial mechanisms versus defined subgroups
The clinical spectrum of Guillain-Barré syndrome (GBS) is summarized in relation to antecedent infections and anti-ganglioside antibodies. Associations exist between a pure motor form of GBS, diarrhea, Campylobacter jejuni infection, and anti-GM1 antibodies; between cranial nerve involvement and Miller Fisher syndrome, C. jejuni infection, and anti-GQ1b antibodies; and between variants, such as severe sensory involvement and cytomegalovirus infection. These three clinical variants are suggested to form the extremes of a continuous spectrum; they are discussed in relation to the more pathologically defined patterns of acute motor axonal neuropathy and acute motor-sensory axonal neuropathy. In particular, patients with a clinically pure motor variant of GBS, diarrhea, anti-GM1 antibodies, or C. jejuni infection seem to respond better to early treatment with high-dose immunoglobulins than to plasma exchange.</p
Helicobacter Genotyping and Detection in Peroperative Lavage Fluid in Patients with Perforated Peptic Ulcer
Introduction and Objectives Certain Helicobacter pylori genotypes are associated with peptic ulcer disease; however, little is known about associations between the H. pylori genotype and perforated peptic ulcer (PPU). The primary aim of this study was to evaluate which genotypes are present in patients with PPU and which genotype is dominant in this population. The secondary aim was to study the possibility of determining the H. pylori status in a way other than by biopsy.
Materials and Methods Serum samples, gastric tissue biopsies, lavage fluid, and fluid from the nasogastric tube were collec
Design and characterization of dielectric filled TM microwave cavities for ultrafast electron microscopy
Microwave cavities oscillating in the TM mode can be used as dynamic
electron-optical elements inside an electron microscope. By filling the cavity
with a dielectric material it becomes more compact and power efficient,
facilitating the implementation in an electron microscope. However, the
incorporation of the dielectric material makes the manufacturing process more
difficult. Presented here are the steps taken to characterize the dielectric
material, and to reproducibly fabricate dielectric filled cavities. Also
presented are two versions with improved capabilities. The first, called a
dual-mode cavity, is designed to support two modes simultaneously. The second
has been optimized for low power consumption. With this optimized cavity a
magnetic field strength of 2.84 0.07 mT was generated at an input power
of 14.2 0.2 W. Due to the low input powers and small dimensions, these
dielectric cavities are ideal as electron-optical elements for electron
microscopy setups
Controlled Dynamics of Interfaces in a Vibrated Granular Layer
We present experimental study of a topological excitation, {\it interface},
in a vertically vibrated layer of granular material. We show that these
interfaces, separating regions of granular material oscillation with opposite
phases, can be shifted and controlled by a very small amount of an additional
subharmonic signal, mixed with the harmonic driving signal. The speed and the
direction of interface motion depends sensitively on the phase and the
amplitude of the subharmonic driving.Comment: 4 pages, 6 figures, RevTe
Numerical model for granular compaction under vertical tapping
A simple numerical model is used to simulate the effect of vertical taps on a
packing of monodisperse hard spheres. Our results are in agreement with an
experimantal work done in Chicago and with other previous models, especially
concerning the dynamics of the compaction, the influence of the excitation
strength on the compaction efficiency, and some ageing effects. The principal
asset of the model is that it allows a local analysis of the packings. Vertical
and transverse density profiles are used as well as size and volume
distributions of the pores. An interesting result concerns the appearance of a
vertical gradient in the density profiles during compaction. Furthermore, the
volume distribution of the pores suggests that the smallest pores, ranging in
size between a tetrahedral and an octahedral site, are not strongly affected by
the tapping process, in contrast to the largest pores which are more sensitive
to the compaction of the packing.Comment: 8 pages, 15 figures (eps), to be published in Phys. Rev. E. Some
corrections have been made, especially in paragraph IV
Cellular localization, accumulation and trafficking of double-walled carbon nanotubes in human prostate cancer cells
Carbon nanotubes (CNTs) are at present being considered as potential nanovectors with the ability to deliver therapeutic cargoes into living cells. Previous studies established the ability of CNTs to enter cells and their therapeutic utility, but an appreciation of global intracellular trafficking associated with their cellular distribution has yet to be described. Despite the many aspects of the uptake mechanism of CNTs being studied, only a few studies have investigated internalization and fate of CNTs inside cells in detail. In the present study, intracellular localization and trafficking of RNA-wrapped, oxidized double-walled CNTs (oxDWNT–RNA) is presented. Fixed cells, previously exposed to oxDWNT–RNA, were subjected to immunocytochemical analysis using antibodies specific to proteins implicated in endocytosis; moreover cell compartment markers and pharmacological inhibitory conditions were also employed in this study. Our results revealed that an endocytic pathway is involved in the internalization of oxDWNT–RNA. The nanotubes were found in clathrin-coated vesicles, after which they appear to be sorted in early endosomes, followed by vesicular maturation, become located in lysosomes. Furthermore, we observed co-localization of oxDWNT–RNA with the small GTP-binding protein (Rab 11), involved in their recycling back to the plasma membrane via endosomes from the trans-golgi network
Цитокіновий профіль у вагітних з хламідійно-вірусною інфекцією
Урогенитальный хламидиоз и вирусная инфекция – это актуальная медико-социальная проблема, поэтому
углубленные исследования клинических, иммунологических и эндокринологических аспектов этой проблемы у
беременных, разработка и внедрение лечебно-профилактических программ является одним из перспективных
резервов снижения репродуктивных потерь, материнской и перинатальной заболеваемости. Вместе с этим,
такие исследования составляют значительный научный интерес и большую практическую ценность.
При изучении механизмов осложнений беременности большой интерес вызывают исследования
функционального состояния клеток ММС (путем определения уровня провоспалительных цитокинов ИЛ -
1β, ФНО -α), а также Т-лимфоцитов (путем определения провоспалительных цитокинов ИЛ -2, ИФН-γ и
провоспалительных цитокинов ИЛ -4, ИЛ -10).Urogenital chlamydia and viral infection are actual medical and social problems. That is why the most promising reserves
to reduce reproductive losses, maternal and perinatal morbidity are deep study of clinical, immunological, microbiological
and endocrinological aspects of this problem among pregnant women, as well as developing and implementing of health
care programs. Moreover, such studies have significant scientific interest and great practical value.
While studying the mechanisms of pregnancy complications, the most interesting are the study of the functional
state of MMS cells (by determining the level of proinflammatory cytokines IL-1β TNF-α), and T-lymphocytes (by
determining the level of proinflammatory cytokines IL-2, IFN-γ and anti-inflammatory cytokines IL-4, IL-10)
The Unique Origin of Colors of Armchair Carbon Nanotubes
The colors of suspended metallic colloidal particles are determined by their
size-dependent plasma resonance, while those of semiconducting colloidal
particles are determined by their size-dependent band gap. Here, we present a
novel case for armchair carbon nanotubes, suspended in aqueous medium, for
which the color depends on their size-dependent excitonic resonance, even
though the individual particles are metallic. We observe distinct colors of a
series of armchair-enriched nanotube suspensions, highlighting the unique
coloration mechanism of these one-dimensional metals.Comment: 4 pages, 3 figure
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