199 research outputs found

    Frequency shifts in gravitational resonance spectroscopy

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    Quantum states of ultracold neutrons in the gravitational field are to be characterized through gravitational resonance spectroscopy. This paper discusses systematic effects that appear in the spectroscopic measurements. The discussed frequency shifts, which we call Stern-Gerlach shift, interference shift, and spectator state shift, appear in conceivable measurement schemes and have general importance. These shifts have to be taken into account in precision experiments

    A spectroscopy approach to measure the gravitational mass of antihydrogen

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    We study a method to induce resonant transitions between antihydrogen (Hˉ\bar{H}) quantum states above a material surface in the gravitational field of the Earth. The method consists of applying a gradient of magnetic field, which is temporally oscillating with the frequency equal to a frequency of transition between gravitational states of antihydrogen. A corresponding resonant change in the spatial density of antihydrogen atoms could be measured as a function of the frequency of applied field. We estimate an accuracy of measuring antihydrogen gravitational states spacing and show how a value of the gravitational mass of the Hˉ\bar{H} atom could be deduced from such a measurement. We also demonstrate that a method of induced transitions could be combined with a free-fall-time measurement in order to further improve the precision

    Phraseology and institutional discourse: Angela Merkel

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    Linguosemiotic approach to the study of phraseological units used by an institutional language personality. The language personality of a politician, in particular Angela Merkel, is considered as an active mechanism for the functioning of institutional discours

    The origin of quasi-periodicities during circular ribbon flares

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    Solar flares with a fan-spine magnetic topology can form circular ribbons. The previous study based on H\alpha line observations of the solar flares during March 05, 2014 by Xu et al. (2017) revealed uniform and continuous rotation of the magnetic fan-spine. Preliminary analysis of the flare time profiles revealed quasi-periodic pulsations (QPPs) with similar properties in hard X-rays, H\alpha, and microwaves. In this work, we address which process the observed periodicities are related to: periodic acceleration of electrons or plasma heating? QPPs are analysed in the H\alpha emission from the centre of the fan (inner ribbon R1), a circular ribbon (R2), a remote source (R3), and an elongated ribbon (R4) located between R2 and R3. The methods of correlation, Fourier, wavelet, and empirical mode decomposition are used. QPPs in H\alpha emission are compared with those in microwave and X-ray emission. We found multi-wavelength QPPs with periods around 150 s, 125 s, and 190 s. The 150-s period is seen to co-exist in H\alpha, hard X-rays, and microwave emissions, that allowed us to connect it with flare kernels R1 and R2. These kernels spatially coincide with the site of the primary flare energy release. The 125-s period is found in the H\alpha emission of the elongated ribbon R4 and the microwave emission at 5.7 GHz during the decay phase. The 190-s period is present in the emission during all flare phases in the H\alpha emission of both the remote source R3 and the elongated ribbon R4, in soft X-rays, and microwaves at 4--8 GHz. We connected the dominant 150-s QPPs with the slipping reconnection mechanism occurring in the fan. We suggested that the period of 125 s in the elongated ribbon can be caused by a kink oscillation of the outer spine connecting the primary reconnection site with the remote footpoint. The period of 190 s is associated with the 3-min sunspot oscillations.Comment: Accepted for publication in A&

    The thylakoid carbonic anhydrase associated with photosystem II is the component of inorganic carbon accumulating system in cells of halo- and alkaliphilic cyanobacterium Rhabdoderma lineare

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    AbstractThe organization of carbonic anhydrase (CA) system in halo- and alkaliphilic cyanobacterium Rhabdoderma lineare was studied by Western blot analysis and immunocytochemical electron microscopy. The presence of putative extracellular α-CA of 60 kDa in the glycocalyx, forming a tight sheath around the cell, and of two intracellular β-CA is reported. We show for the first time that the β-CA of 60 kDa is expressed constitutively and associated with polypeptides of photosystem II (β-CA-PS II). Another soluble β-CA of 25 kDa was induced in low-bicarbonate medium. Induction of synthesis of the latter β-CA was accompanied by an increase in the intracellular pool of inorganic carbon, which suggests an important role of this enzyme in the functioning of a CO2-concentrating mechanism

    Stabilization of enzymes by dormancy autoinducers as a possible mechanism of resistance of resting microbial forms

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    Alkyl-substituted hydroxybenzenes (AHBs), autoinducers of microbial dormancy (or d1 factors), were found to stabilize the structure of protein macromolecules, making them metabolically less active and more resistant to stresses. In vitro experiments with the Bacillus intermedius ribonuclease and chymotrypsin showed that the degree of the physical and chemical stability of these enzymes treated with AHBs depends on their concentration and incubation time. Experiments with RNase, which is capable of refolding, i.e., renaturation after heat denaturation, revealed that AHBs efficiently interact with both intact and denatured proteins. The data obtained allow the inference to be made that d1 factors may play the role of natural chemical chaperons, blocking metabolism in dormant cells through the formation of catalytically inactive thermostable complexes with enzymes. © 2000 MAIK "Nauka/Interperiodica"

    К юбилею УГМУ: олимпиада по терапии как фактор, инициирующий повышение качества подготовки врача

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    В статье раскрывается пример технологии организации проведения студенческой олимпиады по терапии; выделяется роль организационного, методического и творческого этапов

    THE FIRST RUSSIAN EXPERIENCE OF ABO-INCOMPATIBLE KIDNEY TRANSPLANTATION WITH ANTIGEN-SPECIFIC IMMUNOADSORPTION

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    We report the first Russian experience of successful ABO-incompatible kidney transplantation using anti-CD20 + IA + IvIg pretransplant conditioning protocol and tacrolimus + MMF + steroids as maintenance immunosuppression. IA procedures were performed on reusable columns ABO-Adsopak® (POCARD Ltd. Moscow, Russia). IA treatments following the administration of rituximab efficiently lowered the immunoglobulin M (IgM) and G (IgG) anti-A/B antibodies titers in all patients. The transplantation could be performed in all cases and the kidneys showed primary function. Unfortunately, the biopsy-proven clinical antibody-mediated rejection (AMR) occurred in one case. Episo- de of AMR was successfully reversed. On 6, 4 and 2 months follow-up, serum creatinine levels were 117, 127 and 87 μmol/l, respectively. We consider ABO-incompatible transplantation as a safe and promising procedure in particu- lar cases for those patients having related but ABO-incompatible donors. Given the shortage of donor organs ABO- incompatible living donor kidney transplantation may become a treatment of choice for many patients

    Comparative efficacy and safety of mycophenolate mofetil and azathioprine in combination with corticosteroids in the treatment of lymphocytic myocarditis

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    Aim. To study the efficacy and safety of mycophenolate mofetil (MM) in combination with corticosteroids in the treatment of lymphocytic myocarditis in comparison with a standard combination of corticosteroids and azathioprine.Material and methods. The study included 46 patients aged 18 years and older with severe and moderate lymphocytic myocarditis (men, 34; women 12; mean age, 53,5±13,0 years). The diagnosis was verified using endomyocardial biopsy. Symptom duration averaged 9,5 [4; 20.25] months. All patients had class 3 [2,75; 3] heart failure (HF). The main group included 29 patients who received MM 2 g/day, including six patients — instead of azathioprine, which was canceled due to cytopenia (n=3) or insufficient effect (n=3). The comparison group included 17 patients who received azathioprine 150 [100; 150] mg/day. Patients of both groups also received methylprednisolone at a starting dose of 24 [24; 32] and 24 [24; 24] mg/day and standard HF therapy. In 7/2 patients, the parvovirus B19 genome was detected in the myocardium. In all cases, an increase in anticardiac antibody titers was evidence of immune activity. The average follow-up period was 24 [12; 54] months (at least 6 months).Results. The groups were completely comparable in age, initial characteristics and standard drug therapy. In both groups, a comparable significant increase in the ejection fraction (EF) was noted as follows: from 31,2±7,6 to 44,7±8,3% and from 29±9,1 to 46±11,9% (p<0,001). An excellent response to treatment (an increase in EF by 10% or more) was noted in 68,2% and 66,7% of patients, a good response (by 9-5%) — in 27,3% and 14,3%, a poor response (an increase in less than 5% or a decrease in EF) — in 4,5% and 19,0%, respectively. In both groups, we noted the same significant (p<0,01) decrease in pulmonary artery systolic pressure (36,3±12 to 28,1±6,1 mm Hg in the MM group and from 44,1±8,5 to 30,7±12,1 mm Hg in the azathioprine group), left ventricular (LV) end-diastolic dimension (from 6,4±0,6 to 6±0,7 cm and from 6,2±0,5 to 5,8±0,6 cm), LV end-diastolic volume (from 188,7±55,2 to 178,8±57,1 ml and from 167,8±47,5 to 163,3±61,8 ml), LV end-systolic volume (from 130,3±44,1 to 98,4±32 ml and from 118,1±39 to 94,1±46 ml), left atrial volume (from 98,3±30,3 to 86,7±32,6 ml and from 105±27,4 to 91,2±47,3 ml, p<0,05), as well as mitral regurgitation grade. The incidence of deaths was 2 (6,9%) and 2 (8,7%), transplantation — 1 (3,4%) and 1 (4,3%) patients, death+transplantation end point — 3 (10,3%) and 2 (11,8%) without significant differences between the groups. The presence of the parvovirus B19 genome did not affect the results of treatment. The incidence of infectious complications was comparable in both groups (in one case, MM was completely canceled), no new cytopenia cases were noted during the follow-up period.Conclusion. In patients with moderate and severe virus-negative (except for parvovirus B19) lymphocytic myocarditis, the combination of moderate-dose corticosteroids with mycophenolate mofetil 2 g/day is at least no less effective than the standard regimen of immunosuppressive therapy. There was a tendency towards a more pronounced decrease in anticardiac antibody titers in combination with better tolerance (no cases of cytopenia) in MM group. MM in combination with corticosteroids can be recommended as an alternative treatment regimen for lymphocytic myocarditis
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