310 research outputs found

    Modulation of Circumstellar Extinction in a Young Binary System with a Low-Mass Companion in a Noncoplanar Orbit

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    The cyclic activity model of a young star with the low-mass secondary component (q = M2/M1 <= 0.1) accreting a matter from circumbinary disk is considered. It is assumed that the orbit is circular and the disk and orbital planes are non-coplanar. Sets of hydrodynamics models of such a system have been calculated by the SPH method and then the variations of the circumstellar extinction and phase light curves were determined. The calculations showed that depending on the model parameters and orientation of the system in regards to an observer the different in shape and amplitude light curves can be observed. An important property of the considered models is also the dependence of the mass accretion rate onto the components on the phase of the orbital period. The results of the calculation can be used for analysis of the cyclic activity of UX Ori stars and young stars with the long-lasting eclipses.Comment: 14 pages, 7 figure

    Advantages of physical activity of varying intensity for patients with type 1 diabetes and its influence on glucose metabolism

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    Patients with type 1 diabetes mellitus (T1DM) have many benefits from regular exercise, including improved quality of life, lower blood pressure, improved lipid profile, increased insulin sensitivity, decreased insulin dose requirements, improved endothelial function, and reduced risk of micro- and macrovascular complications, as well as overall mortality. Despite these benefits, T1DM patients often do not get enough physical activity (PA) and are less physically active than their non-diabetic peers. The main reason for the low PA in patients with T1DM is the difficulty of glycemic management and the fear of developing hypoglycemia during exercise. Different types of training, such as moderate to high intensity exercise, high intensity interval training, have different effects on glycemic activity during exercise, which can be used to prevent the development of hypoglycemic reactions during and after exercise, along with carbohydrate intake and insulin dose adjustment. Higher-intensity exercise, as well as greater frequency and duration, are associated with a greater reduction in the risk of overall and cardiovascular mortality. Regular physical activity has a positive effect on reducing the risk of micro- and macrovascular complications, general and cardiovascular mortality in patients with type 1 diabetes, regardless of the quality of glycemic control, which can be used for prevention of T1DM complications

    Non-alcoholic fatty liver disease and type 2 diabetes mellitus: the problem of conjunction and phasing

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    The widespread prevalence of non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM), as well as their combination, determines the need for a targeted analysis of this pathology in order to optimize approaches to the diagnosis and treatment of patients with NAFLD and T2DM. As components of the metabolic syndrome, these two diseases have largely similar mechanisms of development and progression, simultaneously increasing the risk of adverse outcomes in comorbid patients. Despite the common pathophysiological mechanisms, the question of the development of NAFLD and T2DM remains significant.Upon conducting literature analysis, two main theories have been identified: alimentary and metabolic. According to the alimentary theory, the primary link in the pathogenesis is obesity and the associated excessive accumulation of free fatty acids and triglycerides in the liver, which subsequently leads to insulin resistance and the development of T2DM. In contrast, the metabolic theory considers diabetes-related insulin resistance as the first hit, which, regardless of obesity, creates preconditions for liver damage. In addition, the review focuses on the consideration of the new concept of Metabolic associated fatty liver disease (MAFLD) as a hepatic manifestation of the metabolic syndrome and considers the clinical phenotypes identified within this pathology. In conclusion, pathogenically based treatment goals in patients with NAFLD and T2DM are overcoming insulin resistance, correcting atherogenic dyslipidemia, and restoring the structures and functions of liver cells

    Prediabetes. A new paradigm for early prevention of cardiovascular disease

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    This literature review focuses on the association of prediabetes with cardiovascular disease (CVD). Recently, much attention has been paid to the study of prediabetes due to its extremely high prevalence and strong association with a high risk of developing serious complications that worsen the quality of kife of patients. Prediabetes is not only a metabolic condition with a high risk of developing type 2 diabetes mellitus (T2DM), but also CVD and death from all causes. This association is true for both patients who do not yet have CVD and those with a history of CVD. Also during the COVID-19 pandemic, attention is drawn to the fact that people with prediabetes have a higher risk of a severe course of infection, complications and a worse prognosis of the disease. This is associated with hyperglycemia, the  presence of  chronic systemic inflammation of  a  low degree of  activity, impaired immune response mechanisms and a procoagulant state in patients with prediabetes, although these disorders are less developed than in patients with T2DM. Therefore, early screening of early disorders of normal metabolism. Since active early intervention at the stage of prediabetes helps to prevent the development of type 2 diabetes and CVD

    Metabolic and cardiovascular features of the course of type 2 diabetes mellitus in men with hypogonadism

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    Introduction. Androgenic deficiency is an important pathogenetic element in the development of metabolic syndrome and cardiovascular diseases in men. It has been proven that in male patients with type 2 diabetes, hypogonadism develops much more often. Objective – to study the metabolic and cardiovascular features of the course of type 2 diabetes mellitus (T2DM) in men with androgen deficiency.Materials and methods. The study included 124 men with type 2 diabetes. To diagnose hypogonadism, the levels of total testosterone (T), sex hormone binding globulin (SHBG), albumin and luteinizing hormone (LH) were measured. Free testosterone (free T) levels were calculated using a calculator from Ghent University Hospital, Belgium. A retrospective analysis of case histories was carried out (spectrum of late complications, the presence of heart attacks and strokes, laboratory data – total cholesterol (CS), triglycerides (TG), fasting blood plasma glucose, basal insulin level, glycated hemoglobin (HbA1c)). The HOMA-IR index was used to determine the degree of insulin resistance.Results. The average age of men was 57.39 ± 9.41 years. The incidence of laboratory-confirmed hypogonadism is 50.81%. An average positive correlation was found between androgen deficiency and the incidence of non-fatal cardiovascular events (r = 0.45, p &lt; 0.05). There was no statistically significant relationship between the presence of hypogonadism and the incidence and degree of late complications of T2DM. Patients with low T levels tended to have higher HOMA-IR values compared to patients with normal T levels (p &lt; 0.05). At the same time, the indicators of carbohydrate and lipid metabolism did not differ significantly in these groups (p &gt; 0.05).Conclusions. The revealed incidence of hypogonadism in men with T2DM corresponds to the data of international studies. The presence of a significant correlation between low testosterone levels and cardiovascular events in patients with T2DM suggests that hypogonadism can be used as an additional criterion for cardiovascular risk. Testosterone deficiency exacerbates insulin resistance, which can lead to weight gain and impair carbohydrate metabolism

    Escherichia coli stress response systems and their reaction to terahertz radiation

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    In this review, we summarize the latest data concerning the reactions of Escherichia coli to nonthermal terahertz radiation and the underlying molecular mechanisms. E. coli is the most simple and convenient model object for studying the effects of terahertz radiation: both its genetics and metabolism are well studied, and it is easily amenable to genetic engineering allowing one to create biosensors using promoters of genes activated by certain stress factors and the reporter GFP protein. Transformed E. coli cells containing biosensors can be used to visualize their reactions to terahertz radiation based on the intensity of GFP fluorescence. In this review, we present data on the response of certain E. сoli stress response systems to terahertz radiation obtained by us, as well as by other authors. We discuss experimental results for E. сoli/ pKatG-GFP, E. сoli/pCopA-GFP, and E. сoli/ pEmrR-GFP biosensors that are used to detect E. сoli genetic networks responding to oxidative stress, copper ion homeostasis failures, and antiseptics, respectively. The obtained data indicate that exposure to nonthermal terahertz radiation induces E. сoli gene networks of oxidative stress and copper ion homeostasis, but does not activate those responding to antibiotics, protonophores, or superoxide anions. The fact that E. сoli/pKatG-GFP and E. сoli/pCopA-GFP biosensors have different activation and reaction periods when exposed to terahertz radiation and natural inducers suggests that reactions of oxidative stress and copper ion homeostasis systems to terahertz radiation are specific

    Bimodal Brightness Oscillations in Models of Young Binary Systems

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    We consider a model for the cyclic activity of young binary stars that accrete matter from the remnants of a protostellar cloud. If the orbit of such a binary system is inclined at a small angle to the line of sight, then the streams of matter and the density waves excited in the circumbinary disk can screen the primary component of the binary from the observer. To study these phenomena by the SPH (smoothed particle hydrodynamics) method, we have computed grids of hydrodynamic models for binary systems based on which we have constructed the light curves as a function of the orbital phase.The main emphasis is on investigating the properties of the brightness oscillations. Therefore, the model parameters were varied within the following ranges: the component mass ratio q = M2 : M1 = 0.2 - 0.5 and the eccentricity e = 0 - 0.7. The parameter that defined the binary viscosity was also varied. We adopted optical grain characteristics typical of circumstellar dust. Our computations have shown that bimodal oscillations are excited in binaries with eccentric orbits, provided that the binary components do not differ too much in mass. In this case, the ratios of the periods and amplitudes of the bimodal oscillations and their shape depend strongly on the inclination of the binary plane and its orientation relative to the observer. Our analysis shows that the computed light curves can be used in interpreting the cyclic activity of UX Ori stars.Comment: 14 pages, 5 figures, 1 tabl
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