183 research outputs found
The Mass Function of Dark Halos in Superclusters and Voids
A modification of the Press-Schechter theory allowing for presence of a
background large-scale structure (LSS) - a supercluster or a void, is proposed.
The LSS is accounted as the statistical constraints in form of linear
functionals of the random overdensity field. The deviation of the background
density within the LSS is interpreted in a pseudo-cosmological sense. Using the
constraints formalism may help us to probe non-trivial spatial statistics of
haloes, e.g. edge and shape effects on boundaries of the superclusters and
voids. Parameters of the constraints are connected to features of the LSS: its
mean overdensity, a spatial scale and a shape, and spatial momenta of higher
orders. It is shown that presence of a non-virialized LSS can lead to an
observable deviation of the mass function. This effect is exploited to build a
procedure to recover parameters of the background perturbation from the
observationally estimated mass function.Comment: 23 pages, 6 figures; to be appeared in Astronomy Reports, 2014, Vol.
58, No. 6, pp. 386-39
The infarct-limiting efficacy of deltorphin-II in old rats with diet-induced metabolic syndrome
Background. The discovery of new pharmacological agents for myocardial protection during reperfusion injury is an urgent goal of modern physiology and pharmacology.The aim of the study. To identify the potential for protecting the myocardium from reperfusion injury by administering the delta-2 opioid receptor agonist deltorphin-II prior to reperfusion in old rats with diet-induced metabolic syndrome.Materials and methods. The study was performed on Wistar rats aged 60 days (young rats) and 450 days (old rats) before the onset of a study. Metabolic syndrome (MetS) was modeled for 84 days with a high-carbohydrate high-fat diet (16 % protein, 21 % fat, 46 % carbohydrate) with the replacement of drinking water with 20 % fructose solution. Myocardial infarction was performed by 45-min coronary occlusion followed by 120-min reperfusion; the size of the area of the necrotic myocardium was determined relative to the size of the hypoperfusion zone. The delta-2 opioid receptor agonist deltorphin-II was administered once intravenously 5 minutes before the end of ischemia.Results. It was found that coronary occlusion and subsequent reperfusion both in groups of young and old rats led to the formation of myocardial infarction (necrosis), the size of which was 45 % of the size of the risk zone. Administration of deltorphin-II in old rats led to a limitation of infarct size to 30 % of the size of the risk zone, i. e. 1.7-fold. The use of deltorphin-II in old rats with MetS contributed to a decrease in infarct size to 27 % of the size of the risk zone (1.5 times). The obtained results demonstrate the cardioprotective efficacy of the delta-2 opioid receptor agonist deltorphin-II in aging and metabolic syndrome in rats.Conclusions. These data may serve as a basis for conducting preclinical studies of deltorphin-II as a drug for treatment of acute myocardial infarction
Структурні дослідження полікристалічних плівок Zn1-xMnxTe
Останнім часом підвищену увагу дослідників в області матеріалознавства привертають плівки халькогенідних сполук групи А2В6, таких як ZnTe, CdSe, ZnS та ін., а також напівмагнітних твердих розчинів на їх основі - Zn1-xMnxTe Cd1-xMnxSe та Zn1-xMnxS. Ці матеріали знаходять широке використання у мікро- та оптоелектроніці, геліоенергетиці та спінтроніці. Останнім часом вони також застосовуються як матеріал ефективних детекторів жорсткого випромінювання та віконні шари плівкових сонячних елементів. Необхідно зазначити суттевий вплив фазового та структурного стану плівок даних сполук на їх оптичні та електрофізичні властивості
Merging of Components in Close Binaries: Type Ia Supernovae, Massive White Dwarfs, and Ap stars
The "Scenario Machine" (a computer code designed for studies of the evolution
of close binaries) was used to carry out a population synthesis for a wide
range of merging astrophysical objects: main-sequence stars with main-sequence
stars; white dwarfs with white dwarfs, neutron stars, and black holes; neutron
stars with neutron stars and black holes; and black holes with black holes.We
calculate the rates of such events, and plot the mass distributions for merging
white dwarfs and main-sequence stars. It is shown that Type Ia supernovae can
be used as standard candles only after approximately one billion years of
evolution of galaxies. In the course of this evolution, the average energy of
Type Ia supernovae should decrease by roughly 10%; the maximum and minimum
energies of Type Ia supernovae may differ by no less than by a factor of 1.5.
This circumstance should be taken into account in estimations of parameters of
acceleration of the Universe. According to theoretical estimates, the most
massive - as a rule, magnetic - white dwarfs probably originate from mergers of
white dwarfs of lower mass. At least some magnetic Ap and Bp stars may form in
mergers of low-mass main sequence stars (<1.5 mass of the Sun) with convective
envelopes.Comment: 15 pages, 4 figure
The role of reactive oxygen species and redoxsensitive protein kinases in the infarction-limiting effect of opioid peptide deltorphin II in cardiac reperfusion in rats
Background. Mortality from acute myocardial infarction with ST-segment elevation in cardiac hospitals ranges from 4.5 to 7 %, and these data has not decreased in recent years. The most common cause of death in patients is cardiogenic shock, the likelihood of which directly depends on infarct size. It is quite clear that there is an urgent need to create drugs to limit the size of infarction and prevent the occurrence of cardiogenic shock.The aim. To evaluate the role of reactive oxygen species and redox-sensitive protein kinases in the infarction-limiting effect of opioid peptide deltorphin II in cardiac reperfusion in rats.Materials and methods. Coronary occlusion (45 min) and reperfusion (120 min) were performed in rats anesthetized with α-chloralose. The selective δ2-opioid receptor agonist deltorphin II, a hydroxyl radical scavenger 2-mercaptoprpionyl glycine (2-MPG), a superoxide radical scavenger tempol, the protein kinase Cδ (PKCδ) inhibitor rottlerin, the PI3-kinase inhibitor wortmannin, the inhibitor of ERK1/2 kinase PD98059 were injected before of reperfusion of the heart.Results. Deltorphin II contributed to a two-fold decrease in infarction size. Injection of 2-MPG, tempol, rottlerin, wortmannin, PD98059 alone had no effect on infarction size in rats. 2-MPG and tempol did not affect the infarction-reducing effect of deltorphin II. Rottlerin, wortmannin, and PD98059 eliminated the cardioprotective effect of deltorphin II.Conclusion. The infarction-reducing effect of deltorphin II does not depend on the production of superoxide radical and hydroxyl radical. Superoxide radical and hydroxyl radical do not play a significant role in reperfusion injury of the heart after coronary occlusion (45 min). PKCδ, PI3-kinase, and ERK1/2 kinase are involved in the infarction-limiting effect of deltorphin II in myocardial reperfusion
Влияние возраста, высокоуглеводной и высокожировой диеты на развитие артериальной гипертензии и поражения почек в эксперименте
Aim. To identify the structural foundations of the pathogenesis of arterial hypertension and kidney disease associated with a high-fat, high-carbohydrate diet and age.Materials and methods. The study was carried out on male Wistar rats aged 60 and 450 days. The animals were divided into 4 groups: group 1 (n = 14) – intact rats (60 days old) fed with a standard diet for 90 days; group 2 (n = 14) – rats (aged 60 days) receiving a high-fat, high-carbohydrate diet for 90 days; group 3 (n = 14) – intact rats (aged 450 days) receiving a standard diet for 90 days; group 4 (n = 14) – rats (aged 450 days) fed with a high-fat, high-carbohydrate diet for 90 days. Clinical and instrumental research methods, enzyme-linked immunosorbent assay, and immunohistochemistry and histology techniques were used in the study.Results. Feeding 60-day-old animals with a high-fat, high-carbohydrate diet resulted in an increase in body weight and abdominal fat, a rise in systolic blood pressure, and moderately pronounced histologic changes in the kidneys. In intact 450-day-old rats, age-related changes prevailed: changes in the myocardial mass, an increase in TGF-β1, morphological changes in the renal tubules and glomeruli. In 450-day-old rats receiving a high-fat, highcarbohydrate diet, the most pronounced increase in both systolic and diastolic blood pressure, a significant rise in serum fibronectin, and destructive changes in the renal tissue were noted.Conclusion. Functional and biochemical signs of arterial hypertension and morphological changes in the kidneys were the most pronounced in 450-day-old rats fed with a high-fat, high-carbohydrate diet.Цель: выявить структурные основы патогенеза артериальной гипертензии и поражения почек, связанных с высокоуглеводной высокожировой диетой (ВУСЖД) и возрастом у крыс линии Wistar.Материал и методы. Исследование проводили на самцах крыс линии Wistar в возрасте 60 и 450 сут. Животных распределяли на четыре группы: 1-я (n = 14) – интактные крысы (возраст 60 сут), содержащиеся на стандартном рационе в течение 90 сут; 2-я (n = 14) – крысы (возраст 60 сут), содержащиеся на ВУВЖД в течение 90 сут; 3-я (n = 14) – интактные крысы (возраст 450 сут), содержащиеся на стандартном рационе в течение 90 сут; 4-я (n = 14) – крысы (возраст 450 сут), содержащиеся на ВУВЖД в течение 90 сут. Использовались клинико-инструментальный, иммуноферментный, иммуногистохимический и гистологический методы исследования.Результаты. Высокоуглеводная высокожировая диета приводила у 60-дневных животных к увеличению массы тела и абдоминального жира, нарастанию систолического артериального давления, появлению умеренно выраженных гистологических изменений почек. У интактных 450-дневных крыс преобладали изменения, связанные с возрастом: увеличение массы миокарда, увеличение TGF-β1 в сыворотке крови, морфологические изменения почечных канальцев и клубочков. У 450-дневных крыс, содержащихся на ВУВЖД, отмечалось наиболее выраженное нарастание как систолического, так и диастолического артериального давления, значительное увеличение концентрации фибронектина в сыворотке крови, выраженные деструктивные изменения в почечной паренхиме.Заключение. Функциональные и биохимические признаки артериальной гипертензии и морфологические изменения в почках были наиболее выражены у 450-дневных крыс, содержавшихся на ВУВЖД
Forward K+ production in subthreshold pA collisions at 1.0 GeV
K+ meson production in pA (A = C, Cu, Au) collisions has been studied using
the ANKE spectrometer at an internal target position of the COSY-Juelich
accelerator. The complete momentum spectrum of kaons emitted at forward angles,
theta < 12 degrees, has been measured for a beam energy of T(p)=1.0 GeV, far
below the free NN threshold of 1.58 GeV. The spectrum does not follow a thermal
distribution at low kaon momenta and the larger momenta reflect a high degree
of collectivity in the target nucleus.Comment: 4 pages, 3 figure
Роль вегетативной нервной системы в стресс-индуцированном повреждении сердца
Aim. To identify the role of the autonomic nervous system in stress cardiomyopathy in an experimental model of Takotsubo syndrome.Materials and methods. The study was carried out on 120 female Wistar rats. Stress modeling was performed by immobilizing animals on the back for 24 hours. Intact rats were used as controls. The rats were decapitated after termination of immobilization under general anesthesia with ether. Stress cardiomyopathy (SCM) was quantified by accumulation of 99mTc pyrophosphate radiopharmaceutical (99mTc PP) in the myocardium. The pharmacological agents used included the ganglionic blocker hexamethonium, administered five times at a dose of 20 mg / kg; guanethidine (50 mg / kg) administered subcutaneously once a day for three days, the last injection was performed 24 hours before immobilization; the muscarinic receptor antagonist atropine methyl nitrate (1 mg / kg); the α1-AR (adrenergic receptor) antagonist prazosin (2 mg / kg); the α2-AR antagonist yohimbine, administered at a dose of 2 mg / kg; the β1-AR antagonist nebivolol (1.2 mg / kg); the β2-AR antagonist ICI 118,551 (0.3 mg / kg); and the β3-AR antagonist L-748337 (0.1 mg / kg).Results. Three-day administration of guanethidine caused a decrease in the degree of 99mTc-PP accumulation in the heart by 35.9%. Hexamethonium did not affect the degree of SCM. The blockade of the muscarinic receptor caused an increase in accumulation of 99mTc-PP by 26.5%. Inhibition of α1-AR did not affect SCM. The blockade of α2-AR caused a 2.2-fold increase in the accumulation compared with stress control. The blockade of β1-AR reduced 99mTc-PP accumulation by 2.5 times. The blockade of β2-AR by ICI 118,551 increased the degree of 99mTcPP accumulation by 34.6%. Inhibition of β3-AR had no effect on SCM.Conclusion. The adrenergic system and β1-adrenergic receptor play an important role in the development of SCM. The parasympathetic nervous system ensures resistance of the heart to stress.Цель. Оценка роли вегетативной нервной системы в стресс-индуцированном повреждении сердца в экспериментальной модели синдрома такотсубо.Материалы и методы. Исследование выполнено на 120 самках крыс линии Вистар. Каждая группа животных состояла из 12 особей. Моделирование стресса осуществляли с помощью иммобилизации животных на спине в течение 24 ч. В качестве контроля использовали интактных особей. Крыс декапитировали после прекращения иммобилизации под общим эфирным наркозом. Количественную оценку стресс-индуцированного повреждения сердца (СИПС) осуществляли по аккумуляции радиофармпрепарата 99mTc-пирофосфата (99mTc-ПФ) в миокарде. Фармакологические агенты вводили внутрибрюшинно: ганглиоблокатор гексаметоний вводили пятикратно в дозе 20 мг/кг; гуанетидин (50 мг/кг) – подкожно 1 раз/сут в течение 3 сут, последнюю инъекцию делали за 24 ч до иммобилизации. Остальные препараты (антагонист М-холинорецепторов атропина метилнитрат (1 мг/кг); антагонист α1-адренорецепторов (АР) празозин (2 мг/кг); антагонист α2-АР йохимбин (2 мг/кг); антагонист β1-АР небиволол (1,2 мг/кг); антагонист β2-АР ICI 118,551 (0,3 мг/кг); антагонист β3-АР L-748337 (0,1 мг/кг)) вводили 2 раза/сут с интервалом 12 ч.Результаты. Трехдневное введение гуанетидина вызвало уменьшение степени аккумуляции 99mTc-ПФ в сердце на 35,9%. Гексаметоний не оказал влияние на степень СИПС. Блокада М-холинорецепторов вызвала усиление аккумуляции 99mTc-ПФ на 26,5%. Ингибирование α1-АР не оказало влияния на СИПС. Блокада α2-АР вызывала усиление аккумуляции в 2,2 раза по сравнению со стресс-контролем. Блокада β1-АР снизила степень аккумуляции 99mTc-ПФ в 2,5 раза. Блокада β2 АР ICI 118,551 увеличила степень аккумуляции 99mTc-ПФ на 34,6%. Ингибирование β3-АР не оказало эффекта на СИПС.Заключение. Симпатоадреналовая система и, в частности, β1-адренорецепторы играют важную роль в развитии СИПС. Парасимпатическая нервная система обеспечивает устойчивость сердца к стрессу
Measurement of the Spin-Dependence of the pbar-p Interaction at the AD-Ring
We propose to use an internal polarized hydrogen storage cell gas target in
the AD ring to determine for the first time the two total spin-dependent pbar-p
cross sections sigma_1 and sigma_2 at antiproton beam energies in the range
from 50 to 450 MeV. The data obtained are of interest by themselves for the
general theory of pbar-p interactions since they will provide a first
experimental constraint of the spin-spin dependence of the nucleon-antinucleon
potential in the energy range of interest. In addition, measurements of the
polarization buildup of stored antiprotons are required to define the optimum
parameters of a future, dedicated Antiproton Polarizer Ring (APR), intended to
feed a double-polarized asymmetric pbar-p collider with polarized antiprotons.
Such a machine has recently been proposed by the PAX collaboration for the new
Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt, Germany.
The availability of an intense stored beam of polarized antiprotons will
provide access to a wealth of single- and double-spin observables, thereby
opening a new window on QCD spin physics.Comment: 51 pages, 23 figures, proposal submitted to the SPS committee of CER
Snow Chemistry Across Antarctica
An updated compilation of published and new data of major-ion (Ca, Cl, K, Mg, Na, NO3, SO4) and methylsulfonate (MS) concentrations in snow from 520 Antarctic sites is provided by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China, Germany, Italy, Japan, Korea, New Zealand, Norway, the United Kingdom, the United States and the national Antarctic programme of Finland. The comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic-wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples. This paper aims to initiate data compilation and administration in order to provide a framework for facilitation of Antarctic-wide snow chemistry discussions across all ITASE nations and other contributing groups. The data are made available through the ITASE web page (http:// www2.umaine.edu/itase/content/syngroups/snowchem.html) and will be updated with new data as they are provided. In addition, recommendations for future research efforts are summarized
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