1,107 research outputs found

    Genetic mechanisms of the influence of light and phototransduction on Drosophila melanogaster lifespan

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    The light of the visible spectrum (with wavelengths of 380-780 nm) is one of the fundamental abiotic factors to which organisms have been adapting since the start of biological evolution on the Earth. Numerous literature sources establish a connection between the duration of exposure to daylight, carcinogenesis and longevity, convincingly showing a significant reduction in the incidence of cancer in blind people, as well as in animal models. On the other hand, the stimulating nature of the effect of continuous illumination on reproductive function was noted, in particular, the effects of increasing the fecundity of females of various species are known. Increase in motor activity and, as a result, in metabolic rate and thermogenesis during permanent exposure to light also reduces the body's energy reserves and lifespan. In principle, in the context of aging, not only the exposure time, but also the age at the onset of exposure to constant illumination matter, the reverse effects are valid for the maintenance of experimental animals in the constant darkness. Over the long period of the evolution of light signal transduction systems, many mechanisms have emerged that allow to form an adequate response of the organism to illumination, modulating the highly conservative signaling cascades, including those associated with aging and lifespan (FOXO, SIRT1, NF-kB, mTOR/S6k, PPARa, etc). In this review, we consider the relationship between lifespan, photoregimens, and also the expression of the genes encoding the phototransduction cascade and the circadian oscillator elements of animal cells. In the present paper, basic transducers of light and other signals, such as the family of TRP receptors, G proteins, phospholipase C, and others, are considered in the context of aging and longevity. A relationship between the mechanisms of thermoreception, the temperature synchronization of the circadian oscillator and the life span is established in the review. Analysis of experimental data obtained from the Drosophila melano-gaster model allowed us to formulate the hypothesis of age-dependent photoresistance - a gradual decrease in the expression of genes associated with phototransduction and circadian oscillators, leading to deterioration in the ability to adapt to the photoregimen and to the increase in the rate of aging

    Features of the intestinal microbiome in patients with thyroid diseases

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    Introduction. Today the search and development of new methods for diagnosing organic or functional pathology of the thyroid gland with an asymptomatic or clinically nonspecific course is an urgent task of endocrinology and therapy. The functioning of the thyroid gland and the state of the human intestinal microbiome are dynamically interrelated. One of the considered promising methods is mass spectrometry of microbial markers of the human intestinal microbiota.The purpose of the study. To study the microbial spectrum and characteristics of the biotic environment of the intestine in patients with thyroid diseases.Materials and methods. 21 patients were examined (8 men and 13 women, median age 40.5 [31.75; 54] years, respectively; 15 with thyroid disease, 6 without thyroid disease). In addition to the standard clinical and laboratory-instrumental examination, patients, colon contents were examined by chromatography-mass spectrometry of microbial materials. The work used descriptive non-parametric statistics with subsequent interpretation. Mean values of indicators and their variance are presented as median, upper and lower quartiles. In relation to representatives of the fecal microbiota, in addition to absolute values, the frequency of occurrence of the microorganism within the reference range, moderate or pronounced deviations was taken into account. The determination of the statistical significance of differences in the relative frequency value was carried out using Fisher’s exact test. The presentation of the results is implemented in the form of range diagrams, compactly depicting a one-dimensional probability distribution, tables. Results. Differences in the composition of the microbiota of the control group and the experimental group for Alcaligenes spp., Staphylococcus spp., Megamonas hypermegale, Peptostreptococcus anaerobius were revealed.Conclusions. The development of thyroid gland pathology is accompanied by significant deviations in the composition of the fecal microbiota, determined by mass spectrometry of microbial markers. In persons with thyroid pathology, in the absence of clinically significant external influences on the intestinal microbiome, a pronounced decrease in the level of Alcaligenes spp., Staphylococcus spp., is detected, a tendency to a decrease in the level of Megamonas hypermegale, Peptostreptococcus anaerobius is determined. Further differentiated study of the composition of the intestinal microbiome in patients with thyroid diseases is required, depending on the nosological affiliation and the nature of the endocrine dysfunction

    Хронологічні ретроспективні показники становлення та розвитку аптечної справи в Україні

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    The article presents the results of the study and generalization of organization and legal aspects of the pharmacy formation in Ukraine in the period of 1709-1917. A detailed analysis of formation and development of the pharmacy chain and characteristics of the personnel policy of pharmacies within a specified period are presented in the article.В статье приведены результаты изучения и обобщения организационно-правовых аспектов становления фармации в Украине в период 1709-1917 гг. Осуществлен детальный анализ становления и развития аптечной сети и особенностей кадровой политики аптечных учреждений в течение указанного периода.У статті наведено результати вивчення та узагальнення організаційно-правових аспектів становлення фармації в Україні у період 1709-1917 рр. Здійснено детальний аналіз становлення і розвитку аптечної мережі та особливостей кадрової політики аптечних установ протягом зазначеного періоду

    On the roots of the Poincare structure of asymptotically flat spacetimes

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    The analysis of vacuum general relativity by R. Beig and N. O Murchadha (Ann. Phys. vol 174, 463 (1987)) is extended in numerous ways. The weakest possible power-type fall-off conditions for the energy-momentum tensor, the metric, the extrinsic curvature, the lapse and the shift are determined, which, together with the parity conditions, are preserved by the energy-momentum conservation and the evolution equations. The algebra of the asymptotic Killing vectors, defined with respect to a foliation of the spacetime, is shown to be the Lorentz Lie algebra for slow fall-off of the metric, but it is the Poincare algebra for 1/r or faster fall-off. It is shown that the applicability of the symplectic formalism already requires the 1/r (or faster) fall-off of the metric. The connection between the Poisson algebra of the Beig-O Murchadha Hamiltonians and the asymptotic Killing vectors is clarified. The value H[K^a] of their Hamiltonian is shown to be conserved in time if K^a is an asymptotic Killing vector defined with respect to the constant time slices. The angular momentum and centre-of-mass, defined by the value of H[K^a] for asymptotic rotation-boost Killing vectors K^a, are shown to be finite only for 1/r or faster fall-off of the metric. Our center-of-mass expression is the difference of that of Beig and O Murchadha and the spatial momentum times the coordinate time. The spatial angular momentum and this centre-of-mass form a Lorentz tensor, which transforms in the correct way under Poincare transformations.Comment: 34 pages, plain TEX, misleading notations changed, discussion improved and corrected, appearing in Class. Quantum Gra

    USp(2k) Matrix Model: Nonperturbative Approach to Orientifolds

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    We discuss theoretical implications of the large k USp(2k) matrix model in zero dimension. The model appears as the matrix model of type IIB superstrings on a large T6/Z2T^{6}/Z^{2} orientifold via the matrix twist operation. In the small volume limit, the model behaves four dimensional and its T dual is six-dimensional worldvolume theory of type I superstrings in ten spacetime dimensions. Several theoretical considerations including the analysis on planar diagrams, the commutativity of the projectors with supersymmetries and the cancellation of gauge anomalies are given, providing us with the rationales for the choice of the Lie algebra and the field content. A few classical solutions are constructed which correspond to Dirichlet p-branes and some fluctuations are evaluated. The particular scaling limit with matrix T duality transformation is discussed which derives the F theory compactification on an elliptic fibered K3.Comment: LaTeX, 29 pages, 3 figures. PostScript problems are fixe

    Bone marrow MRI after autologous transplantation and the effect of residual tumor on progression-free survival of multiple myeloma patients

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    Background . The study of influence of residual tumor mass, determined by magnetic resonance imaging (MRI), on the progression-free survival (PFS) remains an actual problem. Since the visual assessment of tumor bone marrow lesion can be one of the criteria for the subsequent personalized treatment choice in multiple myeloma patients.The objective of study was to determine the effect of bone marrow lesions detected by MRI after autologous hematopoietic stem cells transplantation (auto-HSCT) on PFS in multiple myeloma patients.Materials and methods . The prospective study included 60 patients who underwent spine and pelvic bones MRI on the 100 th day after autoHSCT.Results . Focal bone marrow changes were found in 47 of them – from 1 to 56 lesions (mean 6 ± 9). Significant (p = 0.01) differences of PFS in multiple myeloma patients depending on the presence or absence of tumor mass on 100 th day after auto-HSCT were revealed: with MRI negative status, 2-year PFS was 89 % versus 50 % in a group of patients with residual tumor mass.Conclusion . MRI-negative status after auto-HSCT is a favorable prognostic factor contributing to prolonged disease-free survival

    On Nonperturbative Calculations in Quantum Electrodynamics

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    A new approach to nonperturbative calculations in quantum electrodynamics is proposed. The approach is based on a regular iteration scheme for solution of Schwinger-Dyson equations for generating functional of Green functions. The approach allows one to take into account the gauge invariance conditions (Ward identities) and to perform the renormalization program. The iteration scheme can be realized in two versions. The first one ("perturbative vacuum") corresponds to chain summation in the diagram language. In this version in four-dimensional theory the non-physical singularity (Landau pole) arises which leads to the triviality of the renormalized theory. The second version ("nonperturbative vacuum") corresponds to ladder summation and permits one to make non-perturbative calculations of physical quantities in spite of the triviality problem. For chiral-symmetrical leading approximation two terms of the expansion of the first-step vertex function over photon momentum are calculated. A formula for anomalous magnetic moment is obtained. A problem of dynamical chiral symmetry breaking (DCSB) is considered, the calculations are performed for renormalized theory in Minkowsky space. In the strong coupling region DCSB-solutions arise. For the renormalized theory a DCSB-solution is also possible in the weak coupling region but with a subsidiary condition on the value of α\alpha.Comment: 31 pages, Plain LaTex, no figures. Journal version: some discussion and refs. are adde
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