258 research outputs found
Esophageal Hemorrhagic Syndromes
Esophageal bleeding is one of the most common medical emergencies. It takes the 3rd place among all digestive hemorrhages, and accounts for 14â16 % among all gastrointestinal bleeding. The most common cause of esophageal hemorrhages is Mallory â Weiss esophageal tear (10â12 %), less often â varicose veins of the esophagus in portal hypertension syndrome (up to 4 %) and, in some cases, is esophagitis of various etiologies (up to 1.6 %). The problem of esophageal bleeding is characterized by high incidence, high mortality rate due to constant increase of portal hyper tension cases, recurrences, difficulties in diagnosis, anatomical and physiological features of the esophagus, low efficiency of the main methods of hemostasis. There are various surgical and conservative methods of hemostasis, which show a variety of opinions in the solution to the problem of stopping esophageal bleeding. In Mallory â Weiss syndrome, endoscopic hemostasis is considered to be the preferred method of treatment. Management of portal hypertension is the most difficult task; a wide range of operations is used from the minimally invasive operations to the liver transplantation, as well as endoscopic hemostasis (ligation, sclerotherapy). In esophageal bleeding, due to reflux esophagitis, mainly conservative treatment is suggested, operations are performed with recurrences or complications. Each kind of esophageal hemorrhage is considered as a separate problem
O1 Serogroup Cholera Vibrios Isolated from the Rostov-on-Don Water Bodies in the Course of Surveillance in 2008â2012
Identified are the peculiarities of biological properties and origin of cholera vibrio O1 serogroup strains isolated from the Rostov-on-Don water bodies in the course of surveillance in 2008â2012. 41 atoxigenic V. cholerae O1 strains have been isolated from 767 water samples and investigated. Stable tendency of isolation of increased numbers of atoxigenic V. cholerae O1 strains over time has been demonstrated. In addition, in the strains under study detected have been the genes of additional pathogenicity factors, by PCR genotyping using specific primers for 45 nucleotide sequences associated with V. cholerae pathogenicity. The strains have also been classified according to 19 VNTR-genotypes grouped into 6 clusters based on VNTR-typing using exclusive copyright locus-specific primers. Discovered have been the strains with similar genotypes though isolated at different points both throughout the year and over the period of several years. These ones have probably been imported. They are characterized by a capacity to persist in ambient water bodies for a certain period of time
USAGE OF GIS-TECHNOLOGIES BASED ON THE SPATIAL ANALYSIS FOR DEVELOPMENT OF THE RISK ASSESSMENT TECHNIQUES OF POTENTIAL HAZARD OF ROSTOV REGIONâS TERRITORIES DUE TO ANTHRAX
Purpose: to develop the methodology for risk-assessment of the potential hazard of the Rostov regionâs territory due to anthrax based on the spatial analysis, independent of the administrative division.Materials and Methods: for development the risk-based assessment of potential hazards of territory due to anthrax the registration data of cases for 132 years have been used. The construction of risk cartograms were carried out on the basis of biweight distribution of stationary unfavorable places due to anthrax.Results: the average value of the epizootic index and density of stationary unfavorable places due to anthrax are calculated for 413 administrative units of the Rostov region.Summary: the identification of «risk areas» by using risk-based methodology would provide the more accurate results than the zoning due to administrative territories
Cholera Forecast for the Year 2019 Based on Assessment of Epidemiological Situation Around the World, Across CIS and Russia in 2009â2018
Analysis of cholera incidence for the period of 2009â2018 was performed. The upward tendency in the morbidity rate dynamics around the world (compared to 2009) with an average annual growth rate of 5,352 % was revealed. For the first time during the 7th pandemic caused by V. cholerae O1 El Tor, WHO reported 1227391 cases of cholera world-wide in 2017, out of which 1032481 (84.1%) were registered in Yemen, where the war continues and one of the largest epidemics in the world. There have been cross-border epidemiological complications in several African countries. Endemic foci continue to exist and spread in Asia, Africa and the Caribbean. Under the epidemiological surveillance in Russia, 744 strains of V. cholerae El Tor â ctxAâ tcpAâ, ctxAâ tcpA+ and V. cholerae Đ139 ctxAâ and tcpAâ were isolated from the surface water bodies, as well as single strains of El Tor ctxA+ tcpA+. As a result of INDEL- and PCR-genotyping, the isolation of strains with identical genotypes and new ones was established. To make the prognosis for 2019, the risk of activation (continuation) of the cholera epidemic process in the world was assessed, taking into account emergencies of different origin and risk factors. The cholera forecast at the global level and in Russia for 2019 is unfavorable
Study of low-energy nuclear recoils in liquid argon with the ReD experiment
Liquid Argon (LAr) Time Projection Chambers (TPC) operating in double-phase can detect the nuclear recoils (NR) possibly caused by the elastic scattering of WIMP dark matter particles via light signals from both scintillation and ionization processes. In the scenario of a low-mass WIMP (< 2 GeV/c2), the energy range for the NRs would be below 20 keV, thus making it crucial to characterize the ionization response in LAr TPCs as the lone available detection channel at such low energy. The Recoil Directionality (ReD) project, within the Global Argon Dark Matter Collaboration, aims to measure the ionization yield of a LAr TPC in the recoil energy range of 2-5 keV. The measurement was performed in winter 2023 at the INFN Sezione of Catania and the analysis is ongoing
Recent advances on thermoelectric materials
By converting waste heat into electricity through the thermoelectric power of
solids without producing greenhouse gas emissions, thermoelectric generators
could be an important part of the solution to today's energy challenge. There
has been a resurgence in the search for new materials for advanced
thermoelectric energy conversion applications. In this paper, we will review
recent efforts on improving thermoelectric efficiency. Particularly, several
novel proof-of-principle approaches such as phonon disorder in
phonon-glasselectron crystals, low dimensionality in nanostructured materials
and charge-spin-orbital degeneracy in strongly correlated systems on
thermoelectric performance will be discussed.Comment: 12 pages, 12 figure
Study on cosmogenic activation above ground for the DarkSide-20k project
The activation of materials due to the exposure to cosmic rays may become an
important background source for experiments investigating rare event phenomena.
DarkSide-20k is a direct detection experiment for galactic dark matter
particles, using a two-phase liquid argon time projection chamber filled with
49.7 tonnes (active mass) of Underground Argon (UAr) depleted in 39Ar. Here,
the cosmogenic activity of relevant long-lived radioisotopes induced in the
argon and other massive components of the set-up has been estimated; production
of 120 t of radiopure UAr is foreseen. The expected exposure above ground and
production rates, either measured or calculated, have been considered. From the
simulated counting rates in the detector due to cosmogenic isotopes, it is
concluded that activation in copper and stainless steel is not problematic.
Activation of titanium, considered in early designs but not used in the final
design, is discussed. The activity of 39Ar induced during extraction,
purification and transport on surface, in baseline conditions, is evaluated to
be 2.8% of the activity measured in UAr from the same source, and thus
considered acceptable. Other products in the UAr such as 37Ar and 3H are shown
to not be relevant due to short half-life and assumed purification methods
Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches
The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: 36Ar , 38Ar , and 40Ar . We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019
Directionality of nuclear recoils in a liquid argon time projection chamber
The direct search for dark matter in the form of weakly interacting massive
particles (WIMP) is performed by detecting nuclear recoils (NR) produced in a
target material from the WIMP elastic scattering. A promising experimental
strategy for direct dark matter search employs argon dual-phase time projection
chambers (TPC). One of the advantages of the TPC is the capability to detect
both the scintillation and charge signals produced by NRs. Furthermore, the
existence of a drift electric field in the TPC breaks the rotational symmetry:
the angle between the drift field and the momentum of the recoiling nucleus can
potentially affect the charge recombination probability in liquid argon and
then the relative balance between the two signal channels. This fact could make
the detector sensitive to the directionality of the WIMP-induced signal,
enabling unmistakable annual and daily modulation signatures for future
searches aiming for discovery. The Recoil Directionality (ReD) experiment was
designed to probe for such directional sensitivity. The TPC of ReD was
irradiated with neutrons at the INFN Laboratori Nazionali del Sud, and data
were taken with 72 keV NRs of known recoil directions. The direction-dependent
liquid argon charge recombination model by Cataudella et al. was adopted and a
likelihood statistical analysis was performed, which gave no indications of
significant dependence of the detector response to the recoil direction. The
aspect ratio R of the initial ionization cloud is estimated to be 1.037 +/-
0.027 and the upper limit is R < 1.072 with 90% confidence levelComment: 20 pages, 10 figures, submitted to Eur. Phys. J.
Sensitivity projections for a dual-phase argon TPC optimized for light dark matter searches through the ionization channel
Dark matter lighter than 10 GeV/c encompasses a promising range of
candidates. A conceptual design for a new detector, DarkSide-LowMass, is
presented, based on the DarkSide-50 detector and progress toward DarkSide-20k,
optimized for a low-threshold electron-counting measurement. Sensitivity to
light dark matter is explored for various potential energy thresholds and
background rates. These studies show that DarkSide-LowMass can achieve
sensitivity to light dark matter down to the solar neutrino floor for GeV-scale
masses and significant sensitivity down to 10 MeV/c considering the Migdal
effect or interactions with electrons. Requirements for optimizing the
detector's sensitivity are explored, as are potential sensitivity gains from
modeling and mitigating spurious electron backgrounds that may dominate the
signal at the lowest energies
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