INVESTIGATIONS OF THE CONTENT OF PRENATAL DIAGNOSIS IN THE CONTINGENT OF GENETIC COUNSELLING IN NORTH-EASTERN BULGARIA

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Biochemical, histological and histochemical changes in Aristichthys nobilis Rich. liver exposed to thiamethoxam

Background and purpose: The aim of the present study was to investigate the effects of the insecticide thiamethoxam on some biochemical, histological and histochemical parameters of bighead carp liver (Aristichthys nobilis), which is an economically important fish species for aquaculture. Materials and methods: Different increasing concentrations of 6.6 mg l-1, 10 mg l-1 and 20 mg l-1 of the test chemical under laboratory conditions were tested for their toxicity on fish for 96. The hepatic activity of the enzymes lactate dehydrogenase (LDH), aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were measured. In addition, the hepatic histological structure was observed for alterations, as well as the lipid content was observed by histochemical staining. Results: It was determined that the enzymatic activity of the exposed fish was increased compared to the control group (p<0.05). Furthermore, the enzymatic activity was increased proportionally to the increasing thiamethoxam concentrations. The histological lesions, which were observed in the liver parenchyma, were degenerative and necrotic. The degenerative alterations were as follows: granular, balloon and fatty degeneration. The necrotic alterations in the fish liver were associated with presence of karyopyknosis, karyorrehsis and karyolysis, respectively. The histological alterations in the liver blood vessels were hyperemia and lymphocyte proliferation. Along with the established histological changes in the liver parenchyma, we found presence of fatty degeneration in the hepatocytes using Sudan III staining on cryostat sections. Conclusions: Our study shows that there is a relation between the concentration of the insecticide and biochemical changes, as well the severity of expression of the histological and histochemical alterations in the bighead carp liver. Overall, such experiments could be successfully applied in research and monitoring programs to study the effects of pesticides on fish

Domain diversity and polarization switching in amino acid β-glycine

Piezoelectric materials based on lead zirconate titanate are widely used in sensors and actuators. However, their application is limited because of high processing temperature, brittleness, lack of conformal deposition and, more importantly, intrinsic incompatibility with biological environments. Recent studies on bioorganic piezoelectrics have demonstrated their potential in these applications, essentially due to using the same building blocks as those used by nature. In this work, we used piezoresponse force microscopy (PFM) to study the domain structures and polarization reversal in the smallest amino acid glycine, which recently attracted a lot of attention due to its strong shear piezoelectric activity. In this uniaxial ferroelectric, a diverse domain structure that includes both 180° and charged domain walls was observed, as well as domain wall kinks related to peculiar growth and crystallographic structure of this material. Local polarization switching was studied by applying a bias voltage to the PFM tip, and the possibility to control the resulting domain structure was demonstrated. This study has shown that the as-grown domain structure and changes in the electric field in glycine are qualitatively similar to those found in the uniaxial inorganic ferroelectrics. © 2019 by the authors

Linear magnetoresistance in compensated graphene bilayer

We report a nonsaturating linear magnetoresistance in charge-compensated bilayer graphene in a temperature range from 1.5 to 150 K. The observed linear magnetoresistance disappears away from charge neutrality ruling out the traditional explanation of the effect in terms of the classical random resistor network model. We show that experimental results qualitatively agree with a phenomenological two-fluid model taking into account electron-hole recombination and finite-size sample geometry

β-glycine piezoelectric and ferroelectric properties behavior at elevated temperatures

The research was carried out using equipment of Ural Center for Shared Use "Modern Nanotechnologies" Ural Federal University. The reported study was funded by RFBR according to the research project № 18-32-00390

Polymorphic phase transitions and ferroelectric properties in β-glycine single crystals and micro islands

The research was carried out using equipment of Ural Center for Shared Use "Modern Nanotechnologies" Ural Federal University with the financial support by the Government of the Russian Federation (Resolution 211, Contract 02.A03.21.0006). The reported study was funded by RFBR according to the research project № 18-32-00390

Possibilities of Application of Modern Neurophysiological Methods in Diagnosis of Vibration Disease

Vibration disease is one of the leading in the structure of occupational diseases. A more detailed study of the pathogenesis, expanding the possibilities of diagnosis of vibration disease, is necessary. The aim of the study is to determine the diagnostic value of stabilometry, quantitative sensory testing and neuroenergocarting in vibration disease associated with the combined effects of local and general vibration. Materials and methods. Two groups of patients were examined: with the diagnosis of vibration disease associated with the combined effect of local and general vibration – 50 people (age 48.7 ± 3.1 years), not in contact with vibration – 30 people (age 49.1 ± 2.8 years). The study of the equilibrium function, the determination of the level of the constant potential of the brain by 12 standard leads and the determination of temperature and pain sensitivity. Statistical processing of the results was carried out using the software package “Statistica 6.0” (StatSoft Inc., USA). Differences were considered statistically significant at p &lt; 0.05. Results. In vibration disease, the vertical stance of patients is more unstable than in patients with no contact with vibration. In patients with vibration disease, there is a decrease in the threshold of cold sensitivity and an increase in the threshold of thermal sensitivity and thermal pain compared to the control group. According to our data, the increased level of permanent potential in patients with vibration disease is observed in the central (22.7 (12.6; 30.7) mV) and right central (20.4 (11.5; 27.1) mV), also the average level of permanent capacity in this group is increased – 17.1 (8.4; 25.8) mV.Conclusion. The results obtained indicate the involvement of the neurosensory complex united by single thalamic and cortical centers in the pathological process and confirm the diagnostic value of the methods used

RESEARCH OF STRUCTURE AND PROPERTIES OF HIGH LAYERS OF TIC–TIB–TI, IS FORMED ON THE COMMERCIALLY PURE TITANIUM BY NON-VACUUM ELECTRON BEAM TREATMENT

В работе представлены результаты исследований высокопрочных слоев, полученных на титановом сплаве ВТ1-0 методом вневакуумной электронно-лучевой обработки. В результате наплавки были сформированы слои толщиной от 2,6 до 3,4 мм, содержащие кристаллы карбида и борида титана, распределенные в титановой матрице. Повышение концентрации легирующего порошка способствовало увеличению объемной доли упрочняющей фазы, что привело к образованию таких дефектов, как трещины, и нерастворившихся частиц порошка B4C. Дюрометрические испытания показали, что средний уровень микротвердости легированных слоев повышается до 436–543 HV.This work presents the results of studies of high-impact layers formed on titanium alloy base. The layers with a thickness of 2.6…3.4 mm, containing carbide and titanium boride are formed in the result of treatment. Increasing the concentration of alloying powders increases the volume fraction of the hardening phase, which leads to the formation of defects such as cracks and undissolved powder. Hardness tests have shown that the microhardness of alloying layers value increased to 436–543 HV.Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 16-33-60066 мол_а_дк

Domain structure of β-glycine single crystals

Recent studies of the simplest amino acid glycine (NH2CH2COOH) single crystals revealed that among three polymorphic phases α, β and γ formed at ambient conditions, only β-phase possesses both piezoelectric and ferroelectric properties [1]. The faceted crystals with in-plane polar axis were grown from aqueous solution via drop drying on Pt/SiO/Si substrate in air with controlled relative humidity. The detail experimental study of the neutral and charged domain walls in β-glycine microcrystals using atomic force (AFM) and piezoresponse force microscopy (PFM) was realized by scanning probe microscopes Ntegra Aura (NT-MDT, Russia) and Asylum MFP 3D SA (Asylum Research, USA).The equipment of the Ural Center for Shared Use "Modern Nanotechnology", Ural Federal University has been used