Bending vibrations of stepped rods

Manufacturing stepped rods with segments of sizes proportional to stresses induced in operation is often used to reduce the material consumption in various fields of technology, for example, in the aircraft industry, where the requirements for the weight of structural elements are high. The vibration problems of continuous systems, i.e. systems which masses are considered distributed, are close to the resistance of materials and elasticity theory problems. They are described by partial differential equations. In this case, we consider a homogeneous isotropic material, obeying Hooke’s law. Of all the vibration problems of continuous systems, the transverse vibration problems of shafts and beams is of greatest practical importance. The simplest examples of vibrations of prismatic rods were studied in the 18th century in works on acoustics. But before solving problems of practical importance, the problems of stepped beams, it had taken another two hundred years and the development of approximate methods of solving differential equations. The paper presents a solution to the problem of determining the fundamental frequencies of bending vibrations of two-stepped rods with various boundary conditions, using the approximate Lagrange-Ritz method. The calculation error does not exceed 2.6 %. The fundamental frequency of vibration is defined considering different lengths and stiffness ratios of stepped rod segments. The obtained results can be used in solving practical problems in various fields of technology

Pathology of Sarcoidosis and Differential Diagnostics of other Granulomatous Diseases

Granulomatous diseases are the heterogeneous group of the conditions of different etiologies with a variety of clinic syndromes and morphological features and nonuniform sensitivity to therapy, and the existence of granulomas as general dominate histological expression. Granuloma is indicative of chronic inflammation involving cells of the macrophage system and other inflammatory cells. After the antigen exposure, the activation of T-lymphocytes, macrophages, and epithelioid histiocytes leads to granuloma formation. Granuloma also contains the extracellular matrix produced by fibroblasts, which provide the boundary and isolation of antigen. Their etiology may classify granulomatous diseases as infectious and noninfectious. However, recent studies demonstrate that pathogenic microorganisms may cause the granuloma formation in diseases previously considered as noninfectious. In some cases, differentiation between infectious and noninfectious processes may be problematic. This chapter aims to highlight the multiformity of granulomatous diseases, characterize the pathologic features of different infectious and noninfectious granulomatosis, and delineate the diagnostic approach

Pollution of the coastal waters in the Possyet Bay (Peter the Great Bay, Japan Sea) in conditions of current economic activity

Impact of economic activity on environment quality is assessed for the coastal waters of the Possyet Bay (Peter the Great Bay, Japan Sea). Total volume of the sewage water discharged from coastal sources to the bay and total amount of principal pollutants wasting this water body are calculated. Specific index of sewage for the Possyet Bay is estimated as 0.081 g/m3 that is rather high value. Distribution of petroleum hydrocarbons in the coastal waters is considered: their concentration ranges from 0.025 to 0.065 mg/L. Following to biotesting results, the worst water quality is in the Reid Pallada Bay where the highest inhibitory effect on the byssus thread formation of mussel Crenomytilus grayanus is observed

Легочный вариант гистиоцитоза из клеток Лангерганса у пожилого мужчины

Langerhans cell histiocytosis (LCH) is a heterogeneous group of diseases with typical accumulation of Langerhans cells in different organs and tissues and formation of granulomas with eosinophil infiltration. Pulmonary LCH in adults is an orphan interstitial lung disease. This disease could occur independently on 15% or to be a part of a multisystemic disease in similar proportion of cases. The clinical course of LCH is various and unpredictable and could vary from asymptomatic course to severe progressive pulmonary injury and respiratory failure. The disease could regress spontaneously in a quarter of patients; have the stable course in 50% and progress in 25% of patients. A case of early-stage pulmonary LCH in a 73-year-old smoker was reported in the article. The diagnose was made according to histological and immunohistochemical investigations of VATS biopsy of the lung tissue. Disseminated injury of the lungs without cysts was found that is typical for early stage of LCH and is difficult for detection. Radiological follow-up revealed rapid progression of the disease.Гистиоцитоз из клеток Лангерганса (ГКЛ) – гетерогенная группа заболеваний, характеризующихся накоплением клеток Лангерганса в различных органах и тканях с формированием гранулем с эозинофильной инфильтрацией. Легочный вариант ГКЛ у взрослых относится к редким интерстициальным заболеваниям легких. В 15 %наблюдений может развиться самостоятельное заболевание, с той же частотой ГКЛ является проявлением мультисистемного заболевания. Течение ГКЛ разнообразно и непредсказуемо – от бессимптомных форм до тяжелого прогрессирующего поражения легких, сопровождающегося дыхательной недостаточностью. У #¼ пациентов наблюдается самопроизвольный регресс, у 50 % – стабильное течение заболевания, у 25 % –прогрессирование. Приводится наблюдение гистиоцитоза легких у курящего мужчины 73 лет на ранней стадии развития заболевания, выявленного на основании гистологического и иммуногистохимического исследования привидеоторакоскопической биопсии легкого. В данном наблюдении описано очаговое диссеминированное поражение легких без кистозных изменений верхних и средних долей легких, что характерно для начальной фазы развития ГКЛ, сложной для диагностики. Динамическое рентгенологическое наблюдение свидетельствует о быстропрогрессирующем течении заболевания

Clinical and morphological features of lung injury long-term after SARS-CoV-2 recovery

Aim. To study the clinical and histological profile of lung tissue in patients with persistent pulmonary disease, respiratory symptoms and CT findings after SARS-CoV-2 infection. Materials and methods. The study included 15 patients (7 females and 8 males) with a mean age of 57.7 years. All patients underwent laboratory tests, chest computed tomography, echocardiography, and pulmonary function tests. Pulmonary tissue and bronchoalveolar lavage samples were obtained by fibrobronchoscopy, transbronchial forceps (2 patients), and lung cryobiopsy (11 patients); open biopsy was performed in 2 patients. Cellular composition, herpesvirus DNA, SARS-CoV-2, Mycobacterium tuberculosis complex, galactomannan optical density index, and bacterial and fungal microflora growth were determined in bronchoalveolar lavage. SARS-CoV-2 was also identified in samples from the nasal mucosa, throat and feces using a polymerase chain reaction. Results. The results showed no true pulmonary fibrosis in patients recovered from SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings after SARS-CoV-2 infection. The observed changes comply with the current and/or resolving infection and inflammatory process. Conclusion. Thus, no true pulmonary fibrosis was found in patients after SARS-CoV-2 infection with persistent respiratory symptoms, functional impairment, and CT findings. The observed changes comply with the current and/or resolving infection and inflammatory process

Genotoxic Effects of Exposure to Water-Soluble Fraction of Diesel Fuel in Sand Dollar <i>Scaphechinus mirabilis</i> Gametes

Pollution of marine areas with oil and oil products is steadily growing. As part of this connection, the study of the impact of petroleum hydrocarbons on marine hydrobionts is an urgent issue of modern ecotoxicology. In our study, the genotoxic effect of the water-soluble fraction of diesel fuel at different concentrations on the gametes of the sand dollar Scaphechinus mirabilis was evaluated. It was shown that during the incubation of sperm and eggs of a sand dollar in WAF with an oil hydrocarbon content of 1.32; 2.64; 5.37; 7.92 mg/L caused the destruction of the DNA molecule to varying degrees in both types of gametes. In addition, it has been shown that with an increase in the concentration of petroleum hydrocarbons in WAF, a large number of cells with a high level of DNA damage appear. The success of fertilization after exposure of gametes to a water-soluble extract of petroleum hydrocarbons was also evaluated. The relationship between an increase in the concentration of hydrocarbons in the tested solutions and a decrease in the level of fertilization is shown

Predictors of Progression and Mortality in Patients with Chronic Hypersensitivity Pneumonitis: Retrospective Analysis of Registry of Fibrosing Interstitial Lung Diseases

Hypersensitivity pneumonitis (HP) is an interstitial lung disease (ILD) resulting from an immune-mediated response in susceptible and sensitized individuals to a large variety of inhaled antigens. Chronic HP with a fibrotic phenotype is characterized by disease progression and a dismal prognosis. The aim of this study was to identify predictors of progression and mortality in patients with chronic HP in real clinical practice. Materials and methods: This retrospective, multicenter, observational study used data from a registry of 1355 patients with fibrosing ILDs. The study included 292 patients diagnosed with chronic HP based on the conclusion of a multidisciplinary discussion (MDD). Results: The patients were divided into groups with progressive (92 (30.3%) patients) and nonprogressive pulmonary fibrosis (200 (69.7%) patients). The most significant predictors of adverse outcomes were a DLco < 50% predicted, an SpO2 at the end of a six-minute walk test (6-MWT) < 85%, and a GAP score ≥ 4 points. Conclusion: Pulmonary fibrosis and a progressive fibrotic phenotype are common in patients with chronic HP. Early detection of the predictors of an adverse prognosis of chronic HP is necessary for the timely initiation of antifibrotic therapy

Accelerated Growth, Differentiation, and Ploidy with Reduced Proliferation of Right Ventricular Cardiomyocytes in Children with Congenital Heart Defect Tetralogy of Fallot

The myocardium of children with tetralogy of Fallot (TF) undergoes hemodynamic overload and hypoxemia immediately after birth. Comparative analysis of changes in the ploidy and morphology of the right ventricular cardiomyocytes in children with TF in the first years of life demonstrated their significant increase compared with the control group. In children with TF, there was a predominantly diffuse distribution of Connexin43-containing gap junctions over the cardiomyocytes sarcolemma, which redistributed into the intercalated discs as cardiomyocytes differentiation increased. The number of Ki67-positive cardiomyocytes varied greatly and amounted to 7.0&ndash;1025.5/106 cardiomyocytes and also were decreased with increased myocytes differentiation. Ultrastructural signs of immaturity and proliferative activity of cardiomyocytes in children with TF were demonstrated. The proportion of interstitial tissue did not differ significantly from the control group. The myocardium of children with TF under six months of age was most sensitive to hypoxemia, it was manifested by a delay in the intercalated discs and myofibril assembly and the appearance of ultrastructural signs of dystrophic changes in the cardiomyocytes. Thus, the acceleration of ontogenetic growth and differentiation of the cardiomyocytes, but not the reactivation of their proliferation, was an adaptation of the immature myocardium of children with TF to hemodynamic overload and hypoxemia