37 research outputs found
Large-Scale Sidereal Anisotropy of Galactic Cosmic-Ray Intensity Observed by the Tibet Air Shower Array
We present the large-scale sidereal anisotropy ofgalactic cosmic-ray
intensity in the multi-TeV region observed with the Tibet-IIIair shower array
during the period from 1999 through 2003. The sidereal daily variation of
cosmic rays observed in this experiment shows an excess of relative intensity
around hours local sidereal time, as well as a deficit around 12
hours local sidereal time. While the amplitude of the excess is not significant
when averaged over all declinations, the excess in individual declinaton bands
becomes larger and clearer as the viewing direction moves toward the south. The
maximum phase of the excess intensity changes from 7 at the northern
hemisphere to 4 hours at the equatorial region. We also show that both
the amplitude and the phase of the first harmonic vector of the daily variation
are remarkably independent of primary energy in the multi-TeV region. This is
the first result determining the energy and declination dependences of the full
24-hour profiles of the sidereal daily variation in the multi-TeV region with a
single air shower experiment.Comment: 13 pages, 3 figures, 1 table. Accepted for publication in ApJ
Почечная гемодинамика у больных с хроническими диффузными заболеваниями печени
Statistically confident (р < 0,05) change of blood flow parameters in segmentary and parenchymal arteries in the form of increase of resistance and pulsativity indices has been found that in patients with high-activity chronic hepatite with hyperbilirubinemia. The highest increase of the resistance and pulsativity indices of 0,88 ± 0,05 and 1,24 ± 0,07, respectively, was observed only in segmentary arteries. No statistically confident (р > 0,05) changes were found in maximal and minimal linear parameters of blood flow in these arteries.Установлено, что у больных хроническими гепатитами высокой активности с гипербилирубинемией отмечается статистически достоверное (р < 0,05) изменение параметров кровотока в сегментарных и паренхиматозных артериях в виде повышения значений индексов резистентности и пульсативности. Наибольшее повышение индексов резистентности и пульсативности выявлено только в сегментарных артериях и составляет 0,88 ± 0,05 и 1,24 ± 0,07 соответственно. При этом статистически достоверных (р > 0,05) изменений максимальной и минимальной линейных скоростей кровотока в вышеперечисленных артериях не отмечено
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
Manganese Superoxide Dismutase: Guardian of the Powerhouse
The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as β-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component
NATRIURETIC PEPTIDE AND HIS PROGENITORS AS PREDICTORS OF PROGRESSIVE POSTOPERATIVE LEFT VENTRICLE REMODELING IN PATIENTS WITH ISCHEMIC CARDIOMYOPATHY
The work is devoted to the study of atrial natriuretic peptide (ANP) and its precursors as one of possible predictors of left ventricular repeated remodeling in patients with ischemic cardiomyopathy (ICMP) in the follow-up (postoperative period). Objects of the study are venous blood and intraoperative samples of right atrial auricle. Precursors of NUP were identified in blood serum by the immuno-fluorescence test. Ultrathin slices of auricle biopsy samples were examined with electronmicroscopy with the use of image processing ImageJ software (program). The concentration of NUP precursors in blood plasma and relation of minimal diameter of secretory granules to maximal one in right auricle cardiomyocytes reflect pathological processes taking place in the myocardium of patients with ICMP. Ratio of minimal and maximal diameters of secretory granules is a predictor of chronic heart failure progressing