The image-based finite element evaluation of the deformed state

The article presents one of the possible approaches to modeling objects with anisotropic properties based on images of the study area. Data from such images are taken into account when building a numerical model. In this case, material inhomogeneity can be included by integrating the local stiffness matrix of each finite element with a certain weight function. The purpose of the presented work is to develop a finite element for the formation of a computational ensemble and simulation of mechanical behavior taking into account the data of two-dimensional medical images. To implement the proposed approach, we used the assumption that there is a correlation between the values in the image pixels and the elastic properties of the material. Meshing was based on a four-node plane finite element. This approach allows using the quantitative phase or scanning electronic images, as well as computed tomography data. A number of test problems for compression of elementary geometry samples were calculated. The distal part of the rat femur was considered as a model problem. A computed tomography scan of the sample was used to construct a numerical model taking into account the inhomogeneity of the material distribution inside the organ. The distribution field of the nodal displacements based on data obtained from the images of the study area is presented. Within the framework of a model problem, we considered how a computer tomograph resolution influences the quality of the obtained results. For this purpose, calculations were carried out based on compressed input medical images

In-plane interferometry of terahertz surface plasmon polaritons

The paper is devoted to the development of interferometric schemes for determining the complex refractive index κ = κ′+i•κ″ κ of surface plasmon-polaritons (SPPs) of the terahertz (THz) spectral range. As the value of κ depends on the dielectric constant ϵm of the metal surface guiding the SPPs it can be used for determining m in the far infrared what other optical methods fail to do due to high reflectivity of metals. We discuss two types of THz SPP interferometers in which the interference pattern is formed as a result of the interaction of SPP beams themselves rather than bulk waves produced by these beams. The first type of interferometers are static devices that enable one to investigate fast processes on the metal surface, while the second type are dynamic ones that make it possible to realize Fourier spectroscopy of the metal surface and its transition layer at THz frequencies. Devices of the both types produce interferograms enabling one to determine the real and the imaginary parts of κ. The results of experiments on the interaction of THz SPPs with flat mirrors and beam - splitting plates, the key elements of the THz SPP interferometers, are presented. © Published under licence by IOP Publishing Ltd

Профиль адипоцитокинов и эффективность снижения массы тела у пациентов с метаболически здоровым ожирением

Background: Obesity is a  major risk factor for diabetes mellitus and cardiovascular diseases. Nevertheless, some obese patients have normal parameters of blood arterial pressure, carbohydrate, and lipid metabolism ("metabolically healthy obesity", MHO).Aim: To study adipocytokine levels and to assess the effect of weight loss on cardiometabolic risk factors in patients with metabolically healthy obesity.Materials and methods: We conducted a comparative analysis of the main metabolic parameters and adipocytokine levels in 44  female patients with MHO (according to the IDF criteria of the metabolic syndrome, 2005: obese patients with no more than one additional cardiometabolic risk factor) and in 33 women with metabolically unhealthy obesity (MUHO). We also assessed changes of these indices in the patients who reduced their body weight by ≥ 5% at 6 months.Results: At baseline, body mass index (BMI) and the levels of basal insulin, C-reactive protein (CRP), tumor necrosis factor alfa (TNF-α), adiponectin and retinol-binding protein-4 (RBP-4) in the MHO and MUHO groups were comparable. A  significant difference between these groups was observed for the HOMA index (3.0 and 4.4, respectively; p 0.05), alanine aminotransferase (ALT) (23.49 and 37.39 U/l; p = 0.001), interleukin-6 (0.76 and 1.5 pg/ml; p 0.05), chemerin (322.4 and 369.2 ng/ml; p 0.05), and the duration of obesity (18 and 22.6 years; p 0.05). At 6 months, in those MHO patients, who reduced body weight by ≥ 5% of the initial (66%), there was a significant increase of adiponectin by 4.54 ± 0.83  µg/ml (p 0.05) and a reduction of waist circumference (WC) by -8.6 ± 1 cm (p 0.05), НОМА index by -1.13 ± 0.42 (p 0.05), CRP by -1.7 ± 0.4 mg/l (p 0.05), RBP-4 by 2.9 ± 1.0  ng/ml (p 0.05), and сhemerin by -46.6 ± 17.0 ng/ml (p 0.05). In the MHO group, we found a positive correlation between changes in the adiponectin levels and the degree of reduction in body weight (p 0.01), changes in RBP-4 and WC (p 0.05), and changes in the levels of interleukin-6 and high-density lipoprotein (p 0.05).Conclusion: Compared to the complicated obesity, MHO is associated with a  shorter disease history, and lower levels of the HOMA index, interleukin-6, and chemerin levels. The body mass decrease in MHO is associated with a decrease in the proinflammatory adipocytokine levels and of the HOMA index that determines the need for treatment of obesity, regardless of its phenotype.Актуальность. Ожирение – важнейший фактор риска сахарного диабета и  сердечно-сосудистых заболеваний. Тем не менее ряд больных ожирением имеют сохранные показатели артериального давления, углеводного, липидного обменов – «метаболически здоровое ожирение» (MЗO).Цель – изучить содержание адипоцитокинов, оценить влияние снижения массы тела на факторы кардиометаболического риска у пациентов с МЗО.Материал и методы. Проведен сравнительный анализ основных метаболических показателей, уровня адипоцитокинов у 44 пациенток с MЗO (с учетом критериев метаболического синдрома по International Diabetes Federation (2005) – пациенты с ожирением, имеющие не более одного дополнительного фактора кардиометаболического риска) и 33 женщин с метаболически нездоровым ожирением (МНО). Проведена оценка динамики указанных показателей у пациенток, снизивших массу тела на ≥ 5% через 6 месяцев.Результаты. Исходно показатели индекса массы тела, базального инсулина, С-реактивного белка, фактора некроза опухоли-α, адипонектина и  ретинолсвязывающего белка-4 были сопоставимы в группах MЗO и MНО. Статистически значимое различие между этими группами наблюдалось по показателям индекса HOMA – 3,0 и 4,4 (р 0,05), аланинаминотрансферазы – 23,49 и 37,39 Ед/л (p = 0,001), интерлейкина-6 – 0,76 и 1,85 пг/мл (р 0,05), хемерина – 322,4 и 369,2 нг/мл (р 0,05), а также по длительности ожирения – 18 и 22,6 года (р 0,05) соответственно. Через 6 месяцев в группе пациенток с MЗO, снизивших массу тела на ≥ 5% от исходной (66%), наблюдалось статистически значимое увеличение содержания адипонектина на 4,54 ± 0,83  мкг/мл (p 0,05), уменьшение окружности талии – 8,6 ± 1 см (p 0,005), индекса НОМА – -1,13 ± 0,42 (p 0,05), С-реактивного белка – 1,7 ± 0,4 мг/л (р 0,05), ретинолсвязывающего белка-4 – 2,9 ± 1,0 нг/мл (р 0,05) и хемерина – 46,6 ± 17,0 нг/мл (р 0,05). Мы отметили положительную корреляцию между изменениями уровня адипонектина и степенью снижения массы тела (p 0,01), изменениями ретинолсвязывающего белка-4 и окружности талии (p 0,05) и изменениями уровней интерлейкина-6 и липопротеинов высокой плотности (p 0,05) в группе MЗO.Заключение. По сравнению с осложненным ожирением МЗО ассоциируется с более коротким анамнезом заболевания, более низкими показателями индекса НОМА, интерлейкина-6, хемерина. Снижение массы тела при МЗО сопровождается уменьшением содержания провоспалительных адипоцитокинов и индекса НОМА, что предопределяет необходимость лечения ожирения вне зависимости от фенотипа

Specific features of sodium iodide (NaJ-2H₂O) dehydration in vacuum

Sodium iodide dehydration in vacuum has been studied by baric analysis and spectrophotometry. The decomposition process of NaJ-2H₂O has been shown to be possible at room temperature. During the subsequent heating, water has bben found to be eliminated within 180 to 280°C and 280 to 450°C ranges.Проведено исследование обезвоживания йодида натрия в вакууме методами барического и спектрометрического анализа. Показано, что процесс разложения кристаллогидрата NaJ-2H₂O может протекать при комнатной температуре. В ходе последующего термического нагрева обнаружено выделение воды в диапазонах 180-280°С и 280-450°С.Проведено дослідження зневоднювання йодиду натрію у вакуумі методами баричного та спектрометричного аналізу. Показано, що процес розкладання NaJ-2H₂O може протікати при кімнатній температурі. У ході наступного термічного нагріву виявлено виділення води у діапазонах 180-280°C та 280-450°C

Dehydration of alkali metal iodides in vacuum

The behavior of lithium, sodium, and cesium iodides under heating in vacuum has been studied using baric method and spectrometry. Water release into the gas phase has been found to occur from the materials within various temperature ranges. The water release at the alkali metal iodides seems to be connected with decomposition of the impurity phase containing hydroxyl groups.Исследовано поведение йодидов лития, натрия и цезия при нагревании в вакууме методами барического и спектрометрического анализа. Показано, что для рассматриваемых соединений выделение воды в газовую фазу наблюдается в различных температурных интервалах. Выделение воды при нагревании йодидов щелочных металлов, по-видимому, связано с разложением примесной фазы, содержащей гидроксильные группы.Дослiджено поведiнку йодидiв лiтiю, натрiю та цезiю при нагрiваннi у вакуумi методами баричного та спектрометричного аналiзу. Показано, що для цих сполук спостерiгається вивiльнення води у газову фазу у рiзних температурних iнтервалах. Вивiльнення води при нагрiваннi йодидiв лужних металiв, можливо, пов'язано з розкладом домiшкової фази, яка мiстить гiдроксиднi групи

Meta-Analysis of Non-Alcoholic Fatty Liver Disease and Electromechanical Reconstruction of Myocardium

In developed countries, non-alcoholic fatty liver disease (NAFLD), which results from obesity, has become endemic and kills many adults annually. Health research centers in most countries are looking to examine the relationship between metabolic syndrome (MetS) and metabolic biomarkers. A bleeding-prone standard liver biopsy or costly magnetic resonance imaging scan is used to diagnose NAFLD. The present study aimed to analyze medical databases using various scientific articles; moreover, this experiment analyzed medical databases using published scientific articles related to NAFLD, endovascular treatment, cardiac arrhythmias and conduction disorders, changes in the geometry of atria and ventricles, changes in myocardial mass volume as well as diastolic flow left and right ventricular systolic functions, coronary blood flow, analysis of the dependence of epicardial fat tissue (EFT) thickness, and the presence of chronic heart failure (CHF). It is demonstrated that the index of EFT in NAFLD positively correlated with the criteria of cardiovascular health, values of the carotid intima-media thickness, and calcification of the coronary arteries on the coronary artery calcium scale (P<0.0001). The index of per EFT significantly correlated with the factor of the age of the NAFLD patients (P=0.04), hemoglobin A1C level (P<0.001), systemic inflammatory index (P=0.02), the index of impaired glucose tolerance (P=0.03), and especially, the patient's diabetes factor (P<0.001). In addition, adiponectin levels were significantly lower in individuals with NAFLD (P=0.001) and patients with MetS (P=0.02). NAFLD in association with an increase in epicardial adipose tissue (EAT) is an independent risk factor for atherosclerosis, coronary heart disease, CHF, as well as structural and electrophysiological myocardial remodeling. The study of pathogenetic mechanisms in the context of the role of EAT and clinical monitoring of its condition are urgent problems of modern medicine. Copyright © 2022 b

Bone Stress-Strain State Evaluation Using CT Based FEM

Nowadays, the use of a digital prototype in numerical modeling is one of the main approaches to calculating the elements of an inhomogeneous structure under the influence of external forces. The article considers a finite element analysis method based on computed tomography data. The calculations used a three-dimensional isoparametric finite element of a continuous medium developed by the authors with a linear approximation, based on weighted integration of the local stiffness matrix. The purpose of this study is to describe a general algorithm for constructing a numerical model that allows static calculation of objects with a porous structure according to its computed tomography data. Numerical modeling was carried out using kinematic boundary conditions. To evaluate the results obtained, computational and postprocessor grids were introduced. The qualitative assessment of the modeling data was based on the normalized error. Three-point bending of bone specimens of the pig forelimbs was considered as a model problem. The numerical simulation results were compared with the data obtained from a physical experiment. The relative error ranged from 3 to 15%, and the crack location, determined by the physical experiment, corresponded to the area where the ultimate strength values were exceeded, determined by numerical modeling. The results obtained reflect not only the effectiveness of the proposed approach, but also the agreement with experimental data. This method turned out to be relatively non-resource-intensive and time-efficient

Topography of the crust-mantle boundary beneath the Black Sea Basin.

A map of Moho depth for the Black Sea and its immediate surroundings has been inferred from 3-D gravity modelling, and crustal structure has been clarified. Beneath the basin centre, the thickness of the crystalline layer is similar to that of the oceanic crust. In the Western and Eastern Black Sea basins, the Moho shallows to 19 and 22 km, respectively. Below the Tuapse Trough (northeastern margin, adjacent to the Caucasus orogen), the base of the crust is at 28 km, whereas in the Sorokin Trough, it is as deep as 34 km. The base of the crust lies at 29 and 33 km depths respectively below the southern and northern parts of the Mid-Black Sea Ridge. For the Shatsky Ridge (between the Tuapse Trough and the Eastern Black Sea Basin), the Moho plunges from the northwest (33 km) to the southeast (40 km). The Arkhangelsky Ridge (south of the Eastern Black Sea Basin) is characterised by a Moho depth of 32 km. The crust beneath these ridges is of continental type. © 2004 Elsevier B.V. All rights reserved