1,090 research outputs found

    Scalar and Spinor Particles with Low Binding Energy in the Strong Stationary Magnetic Field Studied by Means of Two-and Three-Dimensional Models

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    On the basis of analytic solutions of Schrodinger and Pauli equations for a uniform magnetic field and a single attractive δ(r)\delta({\bf r})-potential the equations for the bound one-active electron states are discussed. It is vary important that ground electron states in the magnetic field essentially different from the analog state of spin-0 particles that binding energy has been intensively studied at more then forty years ago. We show that binding energy equations for spin-1/2 particles can be obtained without using of a well-known language of boundary conditions in the model of δ\delta-potential that has been developed in pioneering works. Obtained equations are used for the analytically calculation of the energy level displacements, which demonstrate nonlinear dependencies on field intensities. It is shown that in a case of the weak intensity a magnetic field indeed plays a stabilizing role in considering systems. However the strong magnetic field shows the opposite action. We are expected that these properties can be of importance for real quantum mechanical fermionic systems in two- and three-dimensional cases.Comment: 18 page

    Effects of Vacuum Polarization in Strong Magnetic Fields with an Allowance Made for the Anomalous Magnetic Moments of Particles

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    Given the anomalous magnetic moments of electrons and positrons in the one-loop approximation, we calculate the exact Lagrangian of an intense constant magnetic field that replaces the Heisenberg-Euler Lagrangian in traditional quantum electrodynamics (QED). We have established that the derived generalization of the Lagrangian is real for arbitrary magnetic fields. In a weak field, the calculated Lagrangian matches the standard Heisenberg-Euler formula. In extremely strong fields, the field dependence of the Lagrangian completely disappears, and the Lagrangian tends to a constant determined by the anomalous magnetic moments of the particles.Comment: 19 pages, 3 figure

    Superhyperfine interactions in Ce3+ doped LiYF4 crystal: ENDOR measurements

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    The first observation of the resolved Mims electron-nuclear double resonance (ENDOR) spectra from the nearby and remote nuclei of 19F and 7Li nuclei on impurity Ce3+ ions in LiYF4 crystal is reported. It shows that LiYF4:Ce3+ system can be exploited as a convenient matrix for performing spin manipulations and adjusting quantum computation protocols while ENDOR technique could be used for the investigation of electron-nuclear interaction with all the nuclei of the system and exploited for the electron-nuclear spin manipulations.Comment: 4 pages, 2 figures, 1 Table. Reported on Theor-2017 (Kazan, Russia) Conferenc

    Neck atonia with a focal stimulation-induced seizure arising from the SMA: pathophysiological considerations.

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    A 28-year-old patient with pharmacoresistant non-lesional right frontal epilepsy underwent extra-operative intracranial EEG recordings and electrical cortical stimulation (ECS) to map eloquent cortex. Right supplementary motor area (SMA) ECS induced a brief seizure with habitual symptoms involving neck tingling followed by asymmetric tonic posturing. An additional feature was neck atonia. During atonia and sensory aura, discharges were seen in the mesial frontal electrodes and precentral gyrus. Besides motor signs, atonia, although rare and not described in the neck muscles, and sensations have been reported with SMA stimulation. The mechanisms underlying neck atonia in seizures arising from the SMA can be explained by supplementary negative motor area (SNMA) - though this was not mapped in electrodes overlying the ictal onset zone in our patient - or primary sensorimotor cortex activation through rapid propagation. Given the broad spectrum of signs elicited by SMA stimulation and rapid spread of seizures arising from the SMA, caution should be taken to not diagnose these as non-epileptic, as had previously occurred in this patient

    The Energy Level Shifts, Wave Functions and the Probability Current Distributions for the Bound Scalar and Spinor Particles Moving in a Uniform Magnetic Field

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    We discuss the equations for the bound one-active electron states based on the analytic solutions of the Schrodinger and Pauli equations for a uniform magnetic field and a single attractive δ(r)\delta({\bf r})-potential. It is vary important that ground electron states in the magnetic field differ essentially from the analogous state of spin-0 particles, whose binding energy was intensively studied more than forty years ago. We show that binding energy equations for spin-1/2 particles can be obtained without using the language of boundary conditions in the δ\delta-potential model developed in pioneering works. We use the obtained equations to calculate the energy level displacements analytically and demonstrate nonlinear dependencies on field intensity. We show that the magnetic field indeed plays a stabilizing role in considered systems in a case of the weak intensity, but the opposite occurs in the case of strong intensity. These properties may be important for real quantum mechanical fermionic systems in two and three dimensions. We also analyze the exact solution of the Pauli equation for an electron moving in the potential field determined by the three-dimensional δ\delta-well in the presence of a strong magnetic field. We obtain asymptotic expressions for this solution for different values of the problem parameters. In addition, we consider electron probability currents and their dependence on the magnetic field. We show that including the spin in the framework of the nonrelativistic approach allows correctly taking the effect of the magnetic field on the electric current into account. The obtained dependencies of the current distribution, which is an experimentally observable quantity, can be manifested directly in scattering processes, for example.Comment: 31 pages, 10 figure

    Risks for development of metabolic disorders in alimentary constitutional obesity

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    BACKGROUND: alimentary-constitutional obesity due to it’s high prevalence, is the key problem of modern healthcare system. However, obesity is not always accompanied with metabolic disorders, leading to early invalidization and mortality. That’s why it is important to study risks of metabolical nonhealth in obesity.AIM: to detect factors, increasing risks of development of metabolic disbalance in alimentary-constitutional obesity.MATERIALS AND METHODS: In patients with alimentary-constitutional obesity there was performed an examination including anthropometry (body mass index, Waist Circumference, Hip Circumference,waist to hip ratio), blood pressure measurement, laboratory tests – metabolic indexes: glucose, insulin, insulin resistance indexes, leptin, cholesterol, cholesterol of lipoproteins, triglycerides, aspartate aminotransferase, alanine aminotransferase, gamma-glutamiltransferase), body composition measurement by bioelectrical impedance analysis; patients were also interviewed on their behavior (food habits) and physical activity.RESULTS: There were formed two groups depending on metabolic health indexes: main group – metabolically non-healthy obesity (MNHO) - 241 persons (aged 41±12,09, duration of obesity 12,5±9,51 years) with alimentary-constitutional obesity and two or more signs of MS, a comparison group – of metabolically healthy obesity (MHO) – 120 persons (aged 35,5±10,03; p<0,05, duration of obesity 8,0±7,39 years; p<0,05) with alimentary-constitutional obesity and one sign of MS or without it. Data analysis of studied risk factors for development of metabolically non-healthy alimentary-constitutional obesity confirmed that most relevant factor in development of MNHO is abdominal fat mass distribution (increasing of Waist Circumference over 88 sm in females and over 102 sm in mails). At the same time MNHO had correlation not only with classical signs of MS, but also with blood insulin level, insulin resistance indexes, fat metabolism disbalance and liver disfunction. More severed risk for appearance of metabolic disorders have patients over 45 years old with decreased active cell mass (less than 45%), duration of obesity above 10 years and obesity-burdened heredity. In food habits risk of development of metabolically non-healthy obesity was increased in taking of fat milk food, and, on the contrary, - frequent snacks, alcohol free sweet drinks didn’t affect it.CONCLUSION: Development of MNHO is associated not only with the age of patient, duration of obesity, carbohydrate and fat metabolism indexes, but also with decreased percentage of metabolically active tissues and some food habits

    A Novel Pathway for Metabolism of the Cardiovascular Risk Factor Homoarginine by alanine:glyoxylate aminotransferase 2

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    Low plasma concentrations of L-homoarginine are associated with an increased risk of cardiovascular events, while homoarginine supplementation is protective in animal models of metabolic syndrome and stroke. Catabolism of homoarginine is still poorly understood. Based on the recent findings from a Genome Wide Association Study we hypothesized that homoarginine can be metabolized by alanine:glyoxylate aminotransferase 2 (AGXT2). We purified human AGXT2 from tissues of AGXT2 transgenic mice and demonstrated its ability to metabolize homoarginine to 6-guanidino-2-oxocaproic acid (GOCA). After incubation of HepG2 cells overexpressing AGXT2 with isotope-labeled homoarginine-d4 we were able to detect labeled GOCA in the medium. We injected wild type mice with labeled homoarginine and detected labeled GOCA in the plasma. We found that AGXT2 knockout (KO) mice have higher homoarginine and lower GOCA plasma levels as compared to wild type mice, while the reverse was true for AGXT2 transgenic (Tg) mice. In summary, we experimentally proved the presence of a new pathway of homoarginine catabolism - its transamination by AGXT2 with formation of GOCA and demonstrated that endogenous AGXT2 is required for maintenance of homoarginine levels in mice. Our findings may lead to development of novel therapeutic approaches for cardiovascular pathologies associated with homoarginine deficiency

    Risk of Developing Severe Alimentary-Constitutional Obesity and Metabolic Disorders: Interventional Comparative Study

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    Background. The relevance of alimentary-constitutional obesity, especially its severe forms, is associated with a number of metabolic disorders, subsequently leading to serious chronic noncommunicable diseases.Objective. To identify factors that increase the risk of severe alimentary-constitutional obesity and metabolic disorders.Methods. A follow-up group of 426 patients aged 18 to 65 years was formed among those seeking help from an endocrinologist for overweight or obesity. The diagnosis of alimentary-constitutional obesity was confirmed at the initial examination in the outpatient clinic setting. Depending on the severity of obesity and the type of fat deposition according to anthropometric data (body mass index, waist circumference), the study participants were ratified into two study groups. The research was conducted between 2010 and 2017 in outpatient settings and was based on a cross-sectional comparative study. In order to assess the risk of severe obesity and factors associated with it, the authors studied medical history data, results of physical examination, including blood pressure level, laboratory examination with analysis of carbohydrate, fat metabolism and liver function, assessed eating behaviour, and performed diagnosis of anxiety-depressive disorder. Statistical analysis of the results was carried out using Statistica 10 (StatSoft, USA).Results. Women are more likely to see an endocrinologist with less severe obesity than men. Severe obesity risk is higher in middle-aged and elderly people, as well as in hereditary tainted patients and those having a history of obesity for more than 10 years. Severe obesity itself is a significant risk for metabolic events, with a 4-fold higher risk of hyperglycaemia and hypercholesterolaemia (due to very low density lipoproteins) and a 5-fold higher risk of hyperinsulinaemia and insulin resistance.Conclusion. Analysis of severe obesity risks has shown that earlier personal commitment to a healthy lifestyle is essential for weight loss and subsequent improvement of metabolic parameters, particularly in men and those aged 45 years or older

    The transcriptional repressor protein NsrR senses nitric oxide directly via a [2Fe-2S] cluster

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    The regulatory protein NsrR, a member of the Rrf2 family of transcription repressors, is specifically dedicated to sensing nitric oxide (NO) in a variety of pathogenic and non-pathogenic bacteria. It has been proposed that NO directly modulates NsrR activity by interacting with a predicted [Fe-S] cluster in the NsrR protein, but no experimental evidence has been published to support this hypothesis. Here we report the purification of NsrR from the obligate aerobe Streptomyces coelicolor. We demonstrate using UV-visible, near UV CD and EPR spectroscopy that the protein contains an NO-sensitive [2Fe-2S] cluster when purified from E. coli. Upon exposure of NsrR to NO, the cluster is nitrosylated, which results in the loss of DNA binding activity as detected by bandshift assays. Removal of the [2Fe-2S] cluster to generate apo-NsrR also resulted in loss of DNA binding activity. This is the first demonstration that NsrR contains an NO-sensitive [2Fe-2S] cluster that is required for DNA binding activity

    Flavor and Charge Symmetry in the Parton Distributions of the Nucleon

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    Recent calculations of charge symmetry violation(CSV) in the valence quark distributions of the nucleon have revealed that the dominant symmetry breaking contribution comes from the mass associated with the spectator quark system.Assuming that the change in the spectator mass can be treated perturbatively, we derive a model independent expression for the shift in the parton distributions of the nucleon. This result is used to derive a relation between the charge and flavor asymmetric contributions to the valence quark distributions in the proton, and to calculate CSV contributions to the nucleon sea. The CSV contribution to the Gottfried sum rule is also estimated, and found to be small
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