Non-contact method for measurement of the microwave conductivity of graphene

We report a non-contact method for conductivity and sheet resistance measurements of graphene samples using a high Q microwave dielectric resonator perturbation technique, with the aim of fast and accurate measurement of microwave conductivity and sheet resistance of monolayer and few layers graphene samples. The dynamic range of the microwave conductivity measurements makes this technique sensitive to a wide variety of imperfections and impurities and can provide a rapid non-contacting characterisation method. Typically the graphene samples are supported on a low-loss dielectric substrate, such as quartz, sapphire or SiC. This substrate is suspended in the near-field region of a small high Q sapphire puck microwave resonator. The presence of the graphene perturbs both centre frequency and Q value of the microwave resonator. The measured data may be interpreted in terms of the real and imaginary components of the permittivity, and by calculation, the conductivity and sheet resistance of the graphene. The method has great sensitivity and dynamic range. Results are reported for graphene samples grown by three different methods: reduced graphene oxide (GO), chemical vapour deposition (CVD) and graphene grown epitaxially on SiC. The latter method produces much higher conductivity values than the others.Comment: 8 pages, 2 figures and 2 table

Dophamine-dependent disorder of conduct of albino rats with sublimate intoxication in the test of extrapolation deliverance

The article presents the results of the examination, of albino rats in the test of extrapolation deliverance (TED) after sublimate intoxication, and madopar-125 injection with previous sublimate intoxication. The aim. of the work was comparative study of conduct of albino rats with sublimate intoxication and at the influence of ma-dopar-125 in combination with sublimate intoxication, in TED. We used TED method in the research that allows to study cognitive abilities of an animal in stress situation. The results were processed with, software package Statistica 6.0 with use of non-parametric Mann — Whitney parameter. Sublimate was introduced subcutaneously in form, of physiological solution in dose 2 mg/kg during 3 days. In 3 days after ending of sublimate explosion we introduced, physiological solution to the rats of the first group 60 minutes before testing and. the rats of the second, group had intraperitoneal introduction, of madopar-125 that was suspended in 0,9 % NaCl with 125 mg/ kg tween-80 in dose 0,6 ml/100 g of animal's body weight. Animals of control group had physiological solution in the same regimen. It was revealed that in 4 days after the ending of sublimate introduction to albino rats experimental animals in comparison with intact ones had significant increase of number of aversive reactions. After sublimate explosion almost one third of albino rats didn't dive under cylinder's edge. In experimental rats average and total duration of immobilization increased while average duration of clambering on cylinder's walls decreased. Latent period of first movement increased sharply both after toxic influence and after introduction of madopar-125 to the rats with sublimate intoxication in comparison with control animals. Introduction of madopar-125 to the rats with sublimate intoxication completely disturbed conduct of deliverance: no animals dove under cylinder's edge. Albino rats with madopar-125 introduction had significant increase of clambering on cylinder's walls in comparison with animals exposed by sublimate without madopar-125 introduction. Besides the number, average and total duration of aversive reactions in form of jumps in comparison, with control group and with rats after sublimate explosion without pharmacological influence significantly increased

Nature behavioral responses, lipid profile and state of cardiovascular system in lead intoxication modelling on the background of hyperlipidemia in albino rats

The article describes the comparative study of the effect of lead intoxication in healthy animals and in terms of modelled hyperlipidemic condition on lipid metabolism, ECG performance, behavior in the test of the extrapolation of deliverance. The study was performed on 40 albino outbred adult male rats. Modeling hyperlipidemic condition was carried out daily by feeding natural unsalted fat at the rate of 8 grams per animal for 16 days. Lead intoxication was created after the atherogenic diet by adding lead acetate into drinking water in a dose of 50 mg/kg of body weight for 4 weeks. To investigate the lipid metabolism was measured in serum total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol. In the test of extrapolation deliverance 70 % of animals with lead intoxication on the lipid load background did not cope with the task versus 40 % of albino rats in the group with lead acetate exposure alone. All control animals successfully solved the problem of the deliverance test. The deterioration of the functioning of the cardiovascular system of rats with lead poisoning on the background of atherogenic diet was manifested by elongation of intraventricular conduction intervals on an electrocardiogram as compared with animals with lead intoxication alone. Disorders of lipid metabolism were manifested by increased levels of LDL cholesterol in rats with lead intoxication on the background of hyperlipidemia to 0.86 (0.69-1.14) mmol/l compared with the value of 0.67 (0.58-0.79) mmol/l in animals with lead intoxication

Проточные методы, как общий подход к автоматизации химического анализа водных сред (обзор)

The article is devoted to the consideration of general approaches to automating the analysis of aqueous media, which are the main objects of chemical analysis including natural and waste waters, as well as technological media in various industries (microelectronics, biochemical industries, nuclear and thermal power engineering), which are the main consumers of high-purity water used for pre-start flushing of inline equipment to the required cleanliness of surfaces, for preparation of coolants that ensure the operation of nuclear and thermal power plants. In all these cases, the content of impurities in used or spent and intended for discharge aqueous media is strictly regulated. Changes in the content of impurities in controlled media often occur spontaneously due to equipment failure on the controlled objects. Prompt response to such changes and their timely elimination can be performed more efficiently if chemical and technological control of the normalized parameters of aqueous media of any named origin and destination is carried out in a continuous automatic, on-line, mode, which guarantees the exclusion of gaps or delays in obtaining information about equipment failure on a controlled facility in case of technological control or about unauthorized discharges of pollutants in case of environmental control. Possible methodological approaches to the development of systems for continuous chemical monitoring of quality or levels of contamination of aqueous media are considered on the basis of the above prerequisites, and applicability of various flow methods for these purposes is discussed in the order of their appearance in the arsenal of analytical chemists.Keywords: automation, chemical analysis, aqueous media, flow methods, continuous flow analysis, flow injection, cyclic injection, sequential injection.Предлагаемая статья посвящена рассмотрению общих подходов к автоматизации анализа водных сред, являющихся основными объектами химического анализа: природных и сбросных вод, а также технологических сред в различных областях промышленности: микроэлектронике, биохимических производствах, атомной и тепловой энергетике, являющихся главными потребителями воды высокой чистоты, необходимой для предпусковых промывок внутриконтурного оборудования до требуемых кондиций чистоты его поверхностей, для приготовления теплоносителей, обеспечивающих функционирование ядерно- и теплоэнергетических объектов. Во всех перечисленных случаях жестко регламентируется содержание примесей в используемых или отработанных и подлежащих сбросу водных средах. Поскольку изменение содержания примесей в контролируемых средах часто происходит спонтанно и связано с отказами в работе оборудования контролируемых объектов, для оперативного реагирования на них и для их своевременного устранения химико-технологический контроль нормируемых параметров водных сред любого из названных происхождения и назначения предпочтительно осуществлять в непрерывном автоматическом режиме on-line, гарантирующем исключение пропусков или задержек в получении информации об отказах оборудования в контролируемом объекте в случае технологического контроля или о несанкционированных сбросах загрязняющих веществ в случае экологического контроля. Исходя из этих предпосылок, рассматриваются возможные методические подходы к созданию систем непрерывного химического контроля качества или загрязненности водных сред, и обсуждается предпочтительность для этих целей различных вариантов проточных методов в порядке их появления в арсенале химиков-аналитиков.Ключевые слова: автоматизация, химический анализа, водные среды, проточные методы, непрерывный проточный анализ, проточно - инжекционный, циклический инжекционный, последовательный инжекционный

Influence of acute hypoxia in late gestation period on the development of toluene neurotoxic effect in adult albino rats

The aim of the present investigation is to estimate the role of prenatal hypoxia in toluene neurotoxic effect in adult rats. Toluene-induced behavioral and electroencephalographic manifestations were investigated in animals with normal and abnormal embryonic development. To simulate prenatal hypoxia, we gave subcutaneous injections of sodium nitrite to pregnant female rats in a dose of 50 mg/kg on the 18-19th day of gestation. At the age of 3 months the males from the offspring were exposed to toluene inhalation (560 mg/m3, 4 weeks, 4 h/day, 5 days/week). After toluene inhalation exposure we estimated rats' individual behavior by plus maze test and visual and auditory evoked potentials (VEPs and AEPs). Toluene reduced P2N2 interpeak amplitude of VEPs compared with control rats without any latency change. We found out that toluene exposure of rats with acute prenatal hypoxia in late gestation had led to inhibition of motor activity and a statistically significant increase in latency of VEP's N1, AEP's P3 and N1P2 interpeak amplitude of AEP in comparison with all remained groups. Thus, these results show that prenatal hypoxic damage to the central nervous system is an aggravating factor in toluene intoxication in rats

Flow methods as a general approach to automation of the chemical analysis of aqueous media (review)

Предлагаемая статья посвящена рассмотрению общих подходов к автоматизации анализа водных сред, являющихся основными объектами химического анализа: природных и сбросных вод, а также технологических сред в различных областях промышленности: микроэлектронике, биохимических производствах, атомной и тепловой энергетике, являющихся главными потребителями воды высокой чистоты, необходимой для предпусковых промывок внутриконтурного оборудования до требуемых кондиций чистоты его поверхностей, для приготовления теплоносителей, обеспечивающих функционирование ядерно- и теплоэнергетических объектов. Во всех перечисленных случаях жестко регламентируется содержание примесей в используемых или отработанных и подлежащих сбросу водных средах. Поскольку изменение содержания примесей в контролируемых средах часто происходит спонтанно и связано с отказами в работе оборудования контролируемых объектов, для оперативного реагирования на них и для их своевременного устранения химико-технологический контроль нормируемых параметров водных сред любого из названных происхождения и назначения предпочтительно осуществлять в непрерывном автоматическом режиме on-line, гарантирующем исключение пропусков или задержек в получении информации об отказах оборудования в контролируемом объекте в случае технологического контроля или о несанкционированных сбросах загрязняющих веществ в случае экологического контроля. Исходя из этих предпосылок, рассматриваются возможные методические подходы к созданию систем непрерывного химического контроля качества или загрязненности водных сред, и обсуждается предпочтительность для этих целей различных вариантов проточных методов в порядке их появления в арсенале химиков-аналитиков.The article is devoted to the consideration of general approaches to automating the analysis of aqueous media, which are the main objects of chemical analysis including natural and waste waters, as well as technological media in various industries (microelectronics, biochemical industries, nuclear and thermal power engineering), which are the main consumers of high-purity water used for pre-start flushing of inline equipment to the required cleanliness of surfaces, for preparation of coolants that ensure the operation of nuclear and thermal power plants. In all these cases, the content of impurities in used or spent and intended for discharge aqueous media is strictly regulated. Changes in the content of impurities in controlled media often occur spontaneously due to equipment failure on the controlled objects. Prompt response to such changes and their timely elimination can be performed more efficiently if chemical and technological control of the normalized parameters of aqueous media of any named origin and destination is carried out in a continuous automatic, on-line, mode, which guarantees the exclusion of gaps or delays in obtaining information about equipment failure on a controlled facility in case of technological control or about unauthorized discharges of pollutants in case of environmental control. Possible methodological approaches to the development of systems for continuous chemical monitoring of quality or levels of contamination of aqueous media are considered on the basis of the above prerequisites, and applicability of various flow methods for these purposes is discussed in the order of their appearance in the arsenal of analytical chemists

Modification of silica nanoparticles with stereisomers of p-tert-butylthiacalix[4]arene containing four 2-oxo-2-{[3-(triethoxysilyl)prop-1-yl]amino}ethoxy substituents at the lower rim

© 2017, Pleiades Publishing, Ltd. Three stereoisomers (cone, partial cone, and 1,3-alternate) of p-tert-butylthiacalix[4]arene bearing four anchor propyltriethoxysilane substituents at the lower rim were synthesized for the first time. Surface modification of silica nanoparticles (d = 12 nm) with the synthesized macrocycles gave novel hybride thiacalix [4] arene‒SiO 2 particles. The obtained nanostructured adsorbents were found to efficiently extract nitroaromatic compounds from aqueous solutions. The partial cone and 1,3-alternate thiacalix[4]arene–SiO 2 hybrid particles showed affinity to nitrophenols

From experimental biomodeling to personalized medicine

This article presents the results of experimental studies of adverse effects of environmental and occupational exposures on the morphofunctional state of the central nervous system in offspring rats. The results of this study show that newborn offspring of rats exposed to vinyl chloride and mercuric chloride lagged behind the controls in sensory-motor development. There was violated the whole structure of behavior in adult offspring characterized by reduces motor and exploratory activity, increased anxiety in rats. There was abnormal impulse conduction in the neuromuscular apparatus of the hind legs of albino rats and morphological changes in the structure of nervous tissue. Developmental disorders in the offspring may be associated with the processes of accumulation, influence on the genetic apparatus of cells or mediated by epigenetic mechanisms of CNS disorders. A comparative study of the behavioral and cognitive effects of toluene, cerebral bioelectrical activity in rats with a normal embryogenesis and background prenatal hypoxia has been found that toluene neurotoxicity are more pronounced in adult rats exposed to chronic prenatal hypoxia. The results suggest a possible decrease in the sensitivity of neurons to the action of neurotoxicants because of prenatal hypoxic damage. The significance of experimental modeling is to develop approaches to personalized medicine, because knowledge of the previous prenatal pathology or neurointoxication of parents allow study of individual measures of prevention, treatment, and decisions about employment of the younger generation

Reaction of Small and Medium-Sized Enterprises to the Corona Crisis: the Impact of Regional Authorities

Сокращение деловой активности в российской экономике, вызванное антиковидными ограничениями, оказалось значительно меньше прогнозируемого международными финансовыми институтами. Даже сектор малого и среднего предпринимательства, испытавший существенный спад, в 2021 г. продемонстрировал восстановление и устойчивость намерений вести бизнес. Данное исследование ставит целью выяснить, как повлияли региональные власти на активность малого и среднего бизнеса в период кризиса и как это влияние сочеталось с собственными усилиями предпринимателей и экономической свободой в регионе. Для этого в работе использована методология исследовательского кейса на материалах Свердловской области - крупного российского региона с диверсифицированной отраслевой структурой и развитым сектором малого и среднего предпринимательства. В рамках кейс-стади использовано сочетание качественных методов исследования (полуструктурированные интервью с руководителями компаний для выявления глубинных мотивов деятельности и разнообразия реакции бизнеса на внешние вызовы) с количественными методами (рассчитан индекс экономической свободы в регионе за 2002-2020 гг. по методике Д. Коутса, а также с помощью регрессионного анализа по методу МНК оценена взаимосвязь между предпринимательской активностью в Свердловской области и вмешательством государства в экономику региона). Обнаружено, что численность ИП связана с участием государства в экономике региона, в то время как активность юридических лиц из сферы МСП в большей мере связана с экономической свободой. Сокращение и изменение структуры спроса, падение реальных доходов населения, ограничения на трансграничные операции и растущая концентрация рыночной власти в кризисный период ускорили изменение бизнес-моделей компаний в части взаимодействия с клиентами, ценностного предложения, сетевизации и цифровизации бизнеса, а также роста роли бизнес-ассоциаций во взаимодействии компаний и органов государственной власти. Результаты исследования могут быть применены при разработке мер государственной политики в области развития малого и среднего предпринимательства и регионального развития.The decline in Russian business activity due to the Covid restrictions was much lower than forecasted by international financial institutions. Even the small and medium enterprises (SME) sector, which experienced a significant downturn, in 2021 demonstrated a recovery and intentions to conduct business. The present study aims to reveal the impact of regional authorities on the activity of small and medium-sized enterprises during the crisis, coupled with the entrepreneurs’ own efforts and economic freedom in the region. To this end, a case study of Sverdlovsk oblast, a large Russian region with a diversified industrial structure and a developed SME sector, was analysed. Both qualitative and quantitative research methods were utilised in the case study. Qualitative methods include semi-structured interviews with CEOs aimed at identifying deep motives of activity and diversity of business responses to external challenges. As for quantitative methods, the economic freedom index of the region for 2002-2020 was calculated using the Coates method, the relationship between entrepreneurial activity in Sverdlovsk oblast and government intervention in the regional economy was assessed based on the ordinary least squares regression. The study demonstrated that the number of individual entrepreneurs depends on the government participation in the regional economy, while the activity of legal entities is more related to economic freedom. During the crisis, demand reduction and change, real income decline, restrictions on cross-border transactions and a growing concentration of market power accelerated changes in companies’ business models in terms of interaction with consumers, value proposition, networking and digitalisation of business. Additionally, business associations involved in the interaction between companies and public authorities gained importance in this period. The research results can be applied in the design of public policy measures for the small and medium-sized enterprises and regional development

PREVALENCE AND CHARACTERISTICS OF INFERTILITY IN YOUNG WOMEN OF REPRODUCTIVE AGE LIVING IN ZABAYKALSKY DISTRICT

We conducted epidemiological research of WHO record for the estimation of prevalence and characteristics of infertility in young women living in Zabaykalsky District. The research included 2932 women of 18-35 years, 731 of them had infertility. Frequency of infertility exceeds 15% critical level, determined by WHO, and reaches 24,9 % (22,3 % - in town, 25,8 % - in countryside). Secondary infertility appears more often that primary one (54,2 % vs 45,8 %). 44,0 % of young infertile women don't plan pregnancy