CONSTRUCTION OF ISOCOMFORTABLE MICROCLIMATE PARAMETERS VALUES MATRIX

Abstract. In the article is considered the modern approach to the assessment of climate parameters on the basis of the thermal comfort indices in accordance with the requirements of GOST R ISO 7730-2009. For the first time is introduced the concept of isocomfortable values of microclimate parameters, representing a set providing a predetermined thermal comfort level. Are calculated and presented the examples of three-dimensional arrays of given parameters as the convection temperature function from relative humidity and mobility of air. Microclimate parameters ensuring a specified level of thermal comfort were calculated by the method of successive approximations.Proposed in this article matrixes of isocomfortable values of microclimate parameters can be formulated for different combinations of source parameters

Impact of toxicity effects of zinc oxide nanoparticles in rats within acute and subacute experiments

Introduction. Occupational air is contaminated with zinc oxide nanoparticles in the copper smelting industry, especially in the smelting of brass and copper. A wide range of toxic effects with varied clinical symptomatology is observed in zinc and its compounds. Competitive relations with many other metals, including calcium, copper, and iron, are the foundation of most cases of zinc intoxication. Long-term administration of zinc or its compounds to laboratory rodents affects enzymes, carbohydrates and mineral metabolism. Materials and methods. Subchronic intoxication with repeated intraperitoneal injections and acute low respiratory tract reaction to a single intratracheal injection of zinc nanoparticles were simulated in outbred white rats. Water suspensions of zinc oxide nanoparticles with a 30-80 nm diameter were applied in both experimental models. Upon completion of the exposure, the condition of the rats in all groups was evaluated in many generally accepted criteria for toxicity. The student’s t-test was applied for statistical analysis of the obtained data. Results. Moderate intoxication development in a subchronic experiment is demonstrated. Homogeneous ultrastructural changes in the spleen tissue were revealed. Mitochondrial damage with partial or complete loss of crista is the most common. The fragmentation ratio of DNA was found by a statistically significant increase. A single intratracheal injection of zinc oxide nanoparticles revealed the increase in the attraction of cells capable of their phagocytosis (mainly neutrophils) into the low respiratory tract. This shows their cytotoxicity. Conclusion. Moderate general toxic and cytotoxic effects of zinc oxide nanoparticles on the rat body were identified. © 2021 Izdatel'stvo Meditsina. All rights reserved

Benzothiazinones kill Mycobacterium tuberculosis by blocking arabinan synthesis

New drugs are required to counter the tuberculosis (TB) pandemic. Here, we describe the synthesis and characterization of 1,3-benzothiazin-4-ones (BTZs), a new class of antimycobacterial agents that kill Mycobacterium tuberculosis in vitro, ex vivo, and in mouse models of TB. Using genetics and biochemistry, we identified the enzyme decaprenylphosphoryl-beta-d-ribose 2'-epimerase as a major BTZ target. Inhibition of this enzymatic activity abolishes the formation of decaprenylphosphoryl arabinose, a key precursor that is required for the synthesis of the cell-wall arabinans, thus provoking cell lysis and bacterial death. The most advanced compound, BTZ043, is a candidate for inclusion in combination therapies for both drug-sensitive and extensively drug-resistant TB

Общетоксическое и кардиовазотоксическое действие наночастиц оксида кадмия

Introduction. Non-ferrous smelters are one of the critical nanoscale cadmium particles sources in the workplace and ambient air. Materials and methods. The research was performed to evaluate the subchronic toxicity of cadmium oxide nanoparticles (CdO-NPs) in white outbred rats. Male outbred 3.5-month old rats received intraperitoneal injections of CdO-NPs 3 times a week for six weeks (18 in total) in doses of 0.25 mg/kg body mass. After the end of an exposure, there were rated more than 50 indices of universally accepted toxicity criteria (including biochemical and cytomorphometric). Student’s t-test was used for statistical analysis. Results. The hematotoxic effects of CdO-NPs were revealed by a decrease in the hemoglobin content, an increase in the number of reticulocytes, eosinophils, and monocytes. CdO NPs influenced porphyrin metabolism (an increase of δ-aminolevulinic acid in the urine). Liver toxicity resulted in an increase in organ mass and a decrease in albumin content and A/G index. Besides, there was observed a rise in γ-glutamyl transpeptidase and high-density lipoproteins in the blood serum. Oxidative stress level increased (decrease in catalase action and ceruloplasmin content). Endothelin-1 decreased. It may result from an observed decrease in blood pressure indices (statistically significant for mean B.P.). Conclusion. The intoxication of moderate severity was retrieved at the end of the subchronic exposure to cadmium oxide nanoparticles. It characterized mass, hematological, biochemical, and cytomophometric changes. There was found mild but evident cardiovascular toxicity of cadmium oxide nanoparticles. © 2021 Izdatel'stvo Meditsina. All rights reserved

The Multiplicity of Main Sequence Turnoffs in Globular Clusters

We present color-magnitude diagrams of globular clusters for models with self-enrichment and pre-enrichment. The models with self-enrichment turn out to have two or more main sequence turnoff points in the color-magnitude diagram if the fraction of mass lost by the globular cluster under supernova explosions does not exceed 95-97%. The models with pre-enrichment can have only one main sequence turnoff point. We argue that the cluster wCen evolved according to a self-enrichment scenario.Comment: 13 pages, 7 figure

Оценка влияния противовоспалительной терапии в предоперационном периоде на состояние переднего отрезка глаза и исход синустрабекулэктомии по уровню оксигенации гемоглобина в венозном русле

PURPOSE: To study the effect of local preoperative therapy with steroid and non-steroid anti-inflammatory drugs (NSAIDs) (on the level of the oxygen saturation in anterior segment tissues and prolonging the hypotensive effect of trabeculectomy. METHODS: 80 patients with primary open-angle glaucoma were randomized into 4 groups of 20 people according to the study drug: Nepafenac, Dexasone, their non-fixed combination and the control group with no preoperative therapy. All patients underwent trabeculectomy. The patients administered 1 drop of study drug b.i.d. for 2 weeks before the operation and were examined each day for the first week, on weeks 1, 2 and 4, and on months 3, 6 and 12. Oxygen saturation (SO2) was measured in supralimbal and sublimbal deep conjunctival veins before and after 2 weeks of anti-inflammatory therapy. Main outcome measure was the incidence of postoperative surgical or medical interventions (needling, needling revision, hypotensive therapy). RESULTS: In combined anti-inflammatory treatment group, SO2 increased by 5.2% (from 53.6 to 56.4%), in steroid treatment group - by 4.7% (from 52.7 to 55.2%), in nonsteroidal treatment group - by 2.6% (from 53.4 to 54.8%). In controls, no significant changes in SO2 were observed. 50% of patients in the control group needed postoperative needling, 35% in the NSAIDs, 30% - in the steroid drug group and 20% - in the combined therapy group. 10% of the control group and 5% of the NSAIDs required a needling-revision in the postoperative period. Patients from the steroid and combined therapy groups had no need of a needling procedure. 50% of patients in the control group, 35% in the NSAIDs group, 25% in the steroid drug group and 20% in the combined therapy group required further hypotensive therapy. Complete surgery success in the course of the first year amounted to 50% in patients in the control group, 65% in the NSAIDs group, 75% of the steroid drug group and 80% in the combined therapy group. Qualified success during the first year after surgery totaled 100% in all the groups. CONCLUSION: Pre-op topical anti-inflammatory treatment significantly increased venous oxygen saturation in anterior segment tissues which correlated with 1-year rate of absolute success of trabeculectomy as compared with controls. Local preoperative administration of anti-inflammatory drugs helped increase the complete surgery success throughout a year after trabeculectomy as compared to the control group. The best hypotensive effect was noted in the combined therapy group (80%), then - in the steroid and non-steroid monotherapy groups (75% and 65%).ЦЕЛЬ. Изучить влияние местной предоперационной терапии нестероидными и стероидными противовоспалительными препаратами на оксигенацию тканей переднего отрезка глаза и пролонгацию гипотензивного эффекта трабекулэктомии. МЕТОДЫ. 80 пациентам с первичной глаукомой, рандомизированным в 4 группы по 20 человек по исследуемому препарату: нестероидное противовоспалительное средство (НПВС), стероидный препарат, их нефиксированная комбинация и группа контроля без терапии, была выполнена синустрабекулэктомия. Пациенты закапывали по 1 капле препарата 2 раза в день на протяжении 2 недель перед операцией и после ее проведения были обследованы ежедневно в течение первых 7 дней, на 1, 2 и 4 неделе, затем на 3, 6 и 12 месяцах. Степень оксигенации гемоглобина (SO2) определяли в супра-и сублимбальных глубоких конъюнктивальных венах. SO2 определяли до назначения противовоспалительных препаратов и по завершении 2-недельного курса. Критерии оценки исхода - частота послеоперационных хирургических процедур или медикаментозного лечения (нидлинг, нидлинг-ревизия, гипотензивная терапия). РЕЗУЛЬТАТЫ. В группе с комбинированной противовоспалительной терапией SO2 увеличилась на 5,2% (с 53,6 до 56,4%), со стероидной терапией - на 4,7% (с 52,7 до 55,2%), с нестероидной - на 2,6% (с 53,4 до 54,8%). В группе контроля SO2 значимо не изменилась. В группе контроля нидлинг потребовался 50% больным, 35% в группе НПВС, 30% - в группе стероидных препаратов и 20% - с комбинированной терапией. В группе контроля нидлинг-ревизия потребовалась 10%, а в группе НПВС - 5% больных. Пациентам из групп со стероидной и комбинированной терапией нидлинг-ревизия не потребовалась. Доля пациентов, нуждавшихся в гипотензивной терапии, составила 50% в группе контроля, 35% в группе НПВС, 25% в группе стероидных препаратов и 20% в группе с комбинированной терапией. Полный успех в течение первого года составил 50% в группе контроля, 65% в группе НПВС, 75% в группе стероидных препаратов и 80% - в группе с комбинированной терапией. Признанный успех в течение первого года составил 100% во всех группах. ЗАКЛЮЧЕНИЕ. Предоперационное применение местных противовоспалительных препаратов позволило значимо повысить показатель оксигенации в венах тканей переднего отрезка глаза, коррелирующий с процентом полного гипотензивного эффекта синустрабекулэктомии в течение 1 года после вмешательства в сравнении с контрольной группой. Наибольшая гипотензивная эффективность была отмечена в группе с комбинированной терапией (80%), несколько меньший эффект зафиксирован в группах со стероидной и нестероидной монотерапией (75% и 65% соответственно)

Experimental study of negative photoconductivity in n-PbTe(Ga) epitaxial films

We report on low-temperature photoconductivity (PC) in n-PbTe(Ga) epitaxial films prepared by the hot-wall technique on -BaF_2 substrates. Variation of the substrate temperature allowed us to change the resistivity of the films from 10^8 down to 10_{-2} Ohm x cm at 4.2 K. The resistivity reduction is associated with a slight excess of Ga concentration, disturbing the Fermi level pinning within the energy gap of n-PbTe(Ga). PC has been measured under continuous and pulse illumination in the temperature range 4.2-300 K. For films of low resistivity, the photoresponse is composed of negative and positive parts. Recombination processes for both effects are characterized by nonexponential kinetics depending on the illumination pulse duration and intensity. Analysis of the PC transient proves that the negative photoconductivity cannot be explained in terms of nonequilibrium charge carriers spatial separation of due to band modulation. Experimental results are interpreted assuming the mixed valence of Ga in lead telluride and the formation of centers with a negative correlation energy. Specifics of the PC process is determined by the energy levels attributed to donor Ga III, acceptor Ga I, and neutral Ga II states with respect to the crystal surrounding. The energy level corresponding to the metastable state Ga II is supposed to occur above the conduction band bottom, providing fast recombination rates for the negative PC. The superposition of negative and positive PC is considered to be dependent on the ratio of the densities of states corresponding to the donor and acceptor impurity centers.Comment: 7 pages, 4 figure

Исследования оксигенации в офтальмологии

Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g., glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in blood bound to hemoglobin. When the blood is passing through the capillaries, oxygen releases, i.e., oxygenated hemoglobin converts into deoxygenated hemoglobin. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption. Blood oxygen saturation is measured by oximetry. In medicine, the most common method is pulse oximetry which assesses tissue oxygenation. In ophthalmology, this technique was applied to study blood saturation in glaucoma and to analyze the efficacy of glaucoma therapy. Oxygen concentration can also be evaluated by measuring oxygen partial pressure, i.e., pressure from the dissolved oxygen in blood. In ophthalmological practice, this parameter was measured in anterior chamber fluid in glaucoma after instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, retinal oximetry allows for the calculation of oxygen saturation in retinal blood vessels. This technique is based on the assessment of light absorption with blood depending on hemoglobin saturation with oxygen by analyzing spectral composition of light reflected from the retina. Oximetry of bulbar conjunctival and episcleral microvasculature can be performed as well. This technique allows for the evaluation of oxygen saturation in vessels which collect blood from the anterior segment and the characterization of anterior segment metabolism in a number of ocular pathologies and in the course of treatment.Важным показателем жизнеобеспечения является содержание кислорода в жидкостях и тканях организма. Ряд патологий зрительного анализатора, такие как глаукома, предположительно, имеют сосудистый генез, заключающийся в нарушении кровоснабжения и циркуляции кислорода. Большая его часть переносится кровью в виде химического соединения с гемоглобином. Проходя через капилляры, гемоглобин отдает кислород, превращаясь из оксигенированного в дезоксигенированный. Этот процесс сопровождается изменением спектральных характеристик гемоглобина, что обуславливает цвета артериальной и венозной крови. На различиях поглощения света разными формами гемоглобина основан фотометрический метод измерения степени насыщения крови кислородом (сатурация). Для ее измерения проводят оксиметрию. В медицине наиболее распространена тканевая пульсоксиметрия с оценкой показателя тканевой оксигенации. В офтальмологии данный метод использовался при изучении сатурации крови при глаукоме и исследовании эффективности методов ее терапии. Отдельным методом оценки концентрации кислорода является измерение давления растворенного кислорода в крови - парциальное давление кислорода. В офтальмологии исследования данного показателя проводили в жидкости передней камеры, оценивая содержание кислорода при ряде офтальмопатий, включающих различные формы глаукомы, при инстилляциях гипотензивных препаратов, а также в стекловидном теле в области диска зрительного нерва при различных уровнях внутриглазного давления. В настоящее время хорошо развито направление исследования сатурации в сосудах сетчатки - ретинальная оксиметрия, основанная на исследовании поглощения света кровью в зависимости от насыщения гемоглобина кислородом путем анализа спектрального состава света, отраженного от сетчатки. Также проводят оксиметрию эписклерально-конъюнктивальной сосудистой сети, позволяющую оценить сатурацию сосудов, принимающих кровь от переднего отрезка глаза и характеризующих состояние его метаболизма при ряде патологий, а также в процессе лечения

Experimental assessments of metallic and metal oxide nanoparticles toxicity

Nanoparticles of metals and their oxides (Me-NPs) are of special interest in the light of health risks assessment and management, because, along with engineered Me-NPs, there exists usually a substantial fraction of nanoscale ("ultrafine") particles of the same substances within the particle size distribution of condensation aerosols generated by arc-welding, metallurgical, and some chemical technologies. The nonspecific responses of the organism to the impact of Me-NP included: changes in the cytological and some biochemical characteristics of the bronchoalveolar lavage fluid caused by the deposition of particles in the lower airways, various manifestations of systemic toxicity including significant damage to the liver and kidneys, moderate neurological disturbances associated with possible penetration of Me-NP into the brain from the blood as well as from the nasal mucous membrane along the olfactory pathway, a paradoxically low manifestation of pulmonary pathology due to low chronic retention of nanoparticles in the lungs, and a genotoxic effect on the organism level. The toxicity and even genotoxicity of Me-NPs can be significantly attenuated by adequately composed combinations of some bioactive agents in innocuous doses. © Published under licence by IOP Publishing Ltd.Government Council on Grants, Russian FederationMinistry of Science and Higher Education of the Russian Federation: 3.9534.2017/8.9The research was partially supported by the Ministry of Science and Higher Education of the Russian Federation (project 3.9534.2017/8.9) and by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use “Modern Nanotechnology” UrFU was used