834 research outputs found
A brief review of the Russian tea heritage
A Russian author M.E. Saltykov-Shchedrin once said: “What a poorchoice of beverage tea is! Although, if not for the Chinese who gave it to us, a great turmoil would have occurred!” During its long history course, tea has become popular among various continents, taking firm positions in their cultures, economies and historical traditions. Russia, as well as many other countries
Electroreduction of silicon from the NaI–KI–K2SiF6 melt for lithium-ion power sources
Silicon and silicon-based materials are increasingly used in microelectronics, metallurgy and power generation. To date the active study aimed at the development of silicon materials to be used in devices for solar energy conversion, accumulation and storage is underway. In addition, silicon is a promising anode material for lithium-ion fuel cells. In the present paper a possibility of silicon electroreduction from the NaI–KI–K2SiF6 melt in the argon atmosphere is studied. With this aim in view the electrolysis of the NaI–KI–K2SiF6 melt with glassy carbon cathode was performed under galvanostatic and potentiostatic regimes at the temperatures ranging from 650 to 750 °С. The morphology, phase and elemental analyses of the obtained silicon deposits were performed after their separation from the electrolytes by the ICP, SEM-EDX, XRD and Raman spectroscopy methods. Fiber and thread-like silicon samples of 60 to 320 nm in dimeter with admixtures concentrations (mainly oxygen) from 1.2 to 4.6 wt.% were experimentally synthesized. The obtained samples were tested as possible Si/C composite anodes for lithium-ion power sources. The discharge capacity of such power sources after 30 cycles of lithiation-delithiation ranged from 440 to 565 mAh·g–1 and the coloumbic efficiency ranged from 89 to 91%
The evolution of polypharmacy: appropriate and problematic polypharmacy, choosing the right strategy and tactics
The evolution of polypharmacy, which for many years consisted of quantifying concurrently prescribed drugs, has led to an qualitative description: “appropriate polypharmacy”, which may be beneficial for some patients, and “problematic polypharmacy”, which is harmful. The concept of “appropriate polypharmacy” is to prescribe multiple drugs based on the best evidence, taking into account the patient’s clinical condition and potential drug-drug interactions. With age, the prevalence of geriatric syndromes, comorbidity/multimorbidity, and limitation of life expectancy increase, which reduces the positive benefit/risk ratio for most drugs. The problem with polypharmacy is associated with an increased risk of adverse reactions, drug-drug interactions, and decreased patient compliance. To improve polypharmacy, various methodologies are used to optimize drug use for maximum benefit and least harm. Such interventions include professional patient counseling, the use of additional tools (including Bierce’s criteria, STOPP/START, MAI index, etc.), electronic decision-making systems, educational programs. The effectiveness of interventions to reduce polypharmacy has been evaluated in several Cochrane meta-analyzes (2012, 2014, 2018) and showed a decrease in drug misuse and the risk of ADR, but there was no effect on mortality, and few studies found a decrease in the number of hospitalizations. The deprescribing methodology is especially relevant in the context of problematic polypharmacy and is considered an integral component of the continuum of good prescribing practice, promoted as a strategy to reduce polypharmacy and improve patient outcomes. Among other interventions, deprescribing has the most evidence for its utility in preventing drugrelated complications, improving clinical outcomes, and reducing costs. The International Group for Reducing Inappropriate Medication Use & Polypharmacy (IGRIMUP) in 2018 developed 10 recommendations to reduce polypharmacy and potentially inappropriate drugs. Thus, the concept of “appropriate polypharmacy” is a rational approach to optimizing polypharmacy; it should be promoted to replace existing thresholds
Patient-reported outcomes in clinical studies
A review on the use of patient-reported outcomes (PRO) in clinical studies: the concept and content of the PRO, methodology enable PRO in clinical studies, the stages of creation and development, basic types and forms of PRO instruments, psychometric characteristics of the instruments PRO (validation, sensitivity, reliability) of PRO assessment technique
Electrodeposition of Silicon from Molten KCl-K2SiF6for Lithium-Ion Batteries
In this paper we report characteristics and electrochemical properties of silicon fibers used as lithium-ion battery anode. All samples were synthesized by potentiostatic electrodeposition from molten KCl K2SiF6. From molten KCl CsCl K2SiF6 deposition was carried out in galvanostatic mode. Despite the synthesis in inert atmosphere and absence of oxygen containing compounds in the melt resulting silicon after washing contains at least 15 at% oxygen. Silicon fibers synthesized at ?250 mV (vs Si) were the thinnest with diameter as small as 100 nm; average fiber length increased with increasing overvoltage. Addition of CsCl to the melt results in decrease of the average fibers diameter. Silicon fibers synthesized at ?250 mV (vs Si) in KCl K2SiF6 melt showed the best cycling performance with capacity of 1030 mAh g?1 at 0.2 A g?1 discharge current and capacity of 715 mAh g?1 after 10 cycles. Lithium diffusion coefficients calculated from galvanostatic intermittent titration technique (GITT) are common for silicon-based anode. The highest initial diffusion coefficient value of 6.68 10?11 cm2 s?1 was achieved for silicon synthesized from melt with addition of CsCl. Low capacity and rapid capacity fading for all samples can be caused by high silicon dioxide content, further treatment of synthesized silicon is necessary to achieve higher performance. © 2022 The Author(s).This work is performed in the frame of the State Assignment number 075-03-2022-011 dated 14.01.2022 (the theme number FEUZ-2020-0037)
Geotechnical properties of gullying in Tomsk Oblast
The article deals with causes, conditions and factors of gullying in Tomsk Oblast, the case of site Grodnenskaya. A nuclear-power station was planned to be constructed in Closed Administrative Territorial Unit Seversk, which led to geotechnical investigation of the area to study the geological processes developing there. The investigation included reconnaissance traverse of the area, geological and geomorphic descriptions, and sampling. The area and percentage of the territory affected by the geological processes were estimated. As a result, it was proved that the geological processes of the area are conditioned by surface water activity leading to gullying and river erosion, and by both ground water and surface water activity resulting in bog formation. It appears that gullying is caused not only by natural factors but also by technogenic ones
A method of maintaining the competitiveness of vessels on the local freight market during the repair period
With the growing competition on local freight markets, organization and management of freight transportation and fleet operation are aimed at ensuring the competitiveness of shipping com­panies on relevant local freight markets and getting sufficient profit from the current market situation. There are several issues to be considered in this research: the problem of optimization of the pro­cess of vessel repair by using economic and mathematical models that would provide a shipping company within a free market, and full liberalization of the tramp shipping a sustainable position on the relevant local freight market that would contribute to obtaining the greatest possible profits by holding a particular cargo base and regular customers
Genetic Polymorphism of beta1-adrenergic Receptors and the Effect on the Clinical Efficacy of beta-adrenoblockers
Beta-adrenergic blockers are a valuable class of cardiovascular drugs and are widely used in the treatment of arterial hypertension (AH), coronary heart disease, chronic heart failure (CHF), cardiac arrhythmias, significantly improving the prognosis of patients. However, the clinical efficacy of betablockers is largely dependent on the genetic polymorphism of beta1-adrenergic receptors (ADRB1). The aim of the review was a systematic analysis of scientific data from pharmacogenetic studies on the role of beta1-adrenergic receptor polymorphism in the clinical efficacy of beta-blockers in the treatment of hypertension, chronic heart failure, and atrial fibrillation. The results of clinical trials and meta-analyzes were used. Of greatest importance is the genetic polymorphism of beta1-adrenergic receptors of two loci – Arg389Gly and Ser49Gly; the frequency of occurrence of variant and less functionally active alleles Gly389 and Gly49 in Europeans reaches 27% and 15%. The variant Gly389 allele has reduced functional activity and carriers have a weak response to the use of beta-blockers. In carriers of variant alleles Gly389 and Gly49 a reduced hypotensive effect on the use of beta-blockers was observed, and in studies of long-term efficacy, carriage of variant alleles was accompanied by an increase in the frequency and risk of unfavorable outcomes of hypertension. In pharmacogenetic studies, a reduced effect of the effect on myocardial remodeling in patients with CHF for beta-blockers in carriers of the variant Gly389 allele were confirmed. According to two meta-analyzes of trials on use of beta-blockers in patients with CHF, the frequency of increased left ventricle ejection fraction was significantly higher in carriers of the wild Arg389Arg gene type (risk ratio=1.83, p=0,001). In contrast, in atrial fibrillation, the frequency of rhythm control with beta-blockers was achieved better in the presence of the variant allele Gly389 with “loss of function”. Another polymorphic Gly49 allele plays a role in desensitization and down-regulation of beta1-receptor activity, although clinically this effect has been less obvious and contradictory. However, in studies, a more pronounced clinical effect of beta-blockers was observed in carriers of the wild genotype Ser49Ser, as well as in carriers of the haplotype Ser49Ser/Arg389Arg. Thus, genetic polymorphism ADRB1 may be another important predictor of the effectiveness of beta-blockers in clinical practice, which must be taken into account in the treatment of cardiovascular diseases
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