bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Netzentgeltsystematik Strom
Authors: Meyer Jost Hanno
Published: May 2021

The rapid rise of grid charges in recent years has sparked controversy over the distribution of these costs. Germany’s energy transition requires massive investments in the country’s grid, which are born by electricity consumers. The allocation and distribution of these costs is subject to the regulatory pricing method for grid charges of the Stromnetzentgeltverordnung (StromNEV).

The book examines whether the current system of electric grid charges can still provide modern and fair prices. The study shows great need for reform. Vertical and horizontal cost allocation, the circle of users liable to pay those charges as well as the pricing methods and tariff structures of the StromNEV are examined.
Clinical Course and Outcome of Liver Transplantation in Patients with Hepatitis C in Iran
Authors: Ejtehadi Fardad , Farahvashi Paymun , Shamsaeefar Alireza , Niknam Ramin , Sivandzadeh Gholam Reza , Aminlari Ladan , Motazedian Nasrin , Kazemi Kourosh , Nikoupour Hamed , Nikeghbalian Saman , Eghlimi Hesameddin , Taghavi Alireza , Fattahi Mohammadreza , Bagheri Lankarani Kamran , Malek-Hosseini Seyyed Ali
Published: May 2021

Background: Hepatitis C is one of the most common causes of end-stage liver disease and liver transplant worldwide. In recent years, with the rapid advances in the treatment of hepatitis C by direct-acting antiviral drugs (DAAs), the clinical course of the disease as well as liver transplantation have had significant improvement. Also, DAAs have completely replaced interferon-based regimens in the treatment and prevention of HCV recurrence after liver transplant. Objectives: This is the first study that aimed to investigate the clinical course of liver transplantation in patients with hepatitis C in Iran. Methods: This retrospective study was conducted on patients with HCV liver transplantation within five years (2012 - 2017) with the age range of 18 to 65 years at Shiraz Organ Transplant Center. All demographic and clinical data were recorded. Pre-transplant viral load, disease recurrence, graft rejection, and mortality rate were the most important indices in this study. Results: Among 55 transplant patients, 49% had received hepatitis C treatment before liver transplantation and interferon-based regimens were more prevalent. Besides, HCV genotype 3, followed by genotype 1, was the most prevalent one. A liver biopsy was performed in patients with elevated liver enzyme levels. The numbers of patients with HCV recurrence at 2, 6, 12, and 24-month intervals were three, two, zero, and two patients, respectively. At these time intervals, eight, eight, one, and three cases of acute graft rejection were found, respectively. Eight patients died with a one-year survival rate of 85%. Sepsis and infectious complications were the most leading causes of death. Conclusions: This study is the first study of liver transplant patients with hepatitis C in Iran. In the five-year study period, rapid development was made in the treatment of HCV patients. It led to the introduction of DAAs, which replaced interferon-based therapies. The results of this study indicated the high success rate of liver transplantation in patients with hepatitis C in Iran. The results of this study could be used to compare the efficacy of DAAs in future research.
(Des)constituição da rede de atenção à saúde de crianças/adolescentes com necessidades especiais de saúde
Authors: Lima Hentielle Feksa , Oliveira Diúlia Calegari de , Bertoldo Caren Da Silva , Neves Eliane Tatsch
Published: May 2021

Objetivo: descrever como ocorre a utilização dos serviços por crianças e adolescentes com necessidades especiais de saúde (CRIANES) e as implicações destes na constituição da rede de atenção à saúde (RAS). Método: pesquisa qualitativa desenvolvida por meio de entrevistas mediadas pelo Mapa Falante com 17 familiares de CRIANES no primeiro semestre de 2019. Os cenários foram o Pronto-Socorro Pediátrico e a Unidade de Internação Pediátrica de um hospital de ensino. Os dados foram submetidos à análise temática indutiva. Resultados: os temas oriundos da análise foram: Caminho percorrido para a articulação da rede de atenção à saúde de CRIANES e Desafios para a articulação da rede de atenção à saúde de CRIANES. Os temas apontaram a descontinuidade da rede de atenção à saúde de CRIANES. Conclusão: as famílias não possuem um fluxo de referência e contrarreferência consolidado nas RAS e enfrentam constantes peregrinações pela rede na procura pelos serviços de saúde.
Trade in counterfeit goods in Serbia: Methodological approach and quantification
Authors: Radulović Branko , Savić Miljan
Published: May 2021

The paper represents the first step in quantifying the categories of goods with the highest risk of being counterfeit during import into Serbia. Firstly, we present a methodology for quantifying the level of counterfeiting, its advantages, and its limitations. Secondly, we determine the product categories most likely to contain counterfeit products. Likewise, by using the OECD methodology, the GTRIC-p indicator for Serbia was formed, enabling comparison with OECD member countries. Based on the results, Serbia does not significantly differ from EU countries in terms of structure and product categories most at risk. The negative effects of imports of counterfeit products are borne mainly by the foreign intellectual property rights holders whose counterfeit products are imported into Serbia. In this context, despite the legal framework in place, incentives for its proper implementation are questionable.
Revisiting spillover effect: An empirical evidence from GARCH-ARMA approach
Authors: Dolfriandra Huruta , Hananto Andreas , Forestal Roberto , Elangovan Anboli , Diaz John
Published: May 2021

This study analyzes the spillover effect of markets' commodity, exchange rate, and stock price. Starting from July 1, 2009, the daily data to December 31, 2019, are conducted in our study. The GARCH-ARMA approach has been undertaken in this study. The results show that four pairs experience the unidirectional (positive) spillover effect of return. Yet, the spillover effect of volatility shows a two-way relationship (both positive and negative) between commodity markets, stock prices, and exchange rates. To conclude, both stock prices and gold are volatility's net transmitters to other markets, while the EURUSD market is some markets' net receiver of volatility.
Fuel savings by using better-quality insulation in refrigerated vans
Authors: Jovanović Branislav , Maljković Miloš , Stamenković Dragan , Popović Vladimir
Published: May 2021

An additional attention must be payed to the energy efficiency of refrigerated vans transporting perishable foodstuffs, because inefficient operation of refrigeration units installed on these vehicles increases fuel consumption and exhaust gases emissions. The amount of fuel consumed by mechanical refrigeration unit drive can be reduced in many ways. This paper is analysing the impact of thermal insulation quality on the fuel consumed by mechanical refrigeration unit installed on a typical van. The results of the research show that by choosing better-quality thermal insulation around € 420 can be saved annually on fuel consumed by mechanical refrigeration unit driven by vehicle's engine while transporting deeply frozen fish at -20 °C (or other foodstuffs at given temperature). If the van is transporting raw meat (for example) at 0 °C annual savings can be around € 110. When the van is used for transport of deeply frozen fish the investment will pay off after 3.5 years of vehicle exploitation, while if the raw meat is transported the investment will pay off after approximately 14 years. The analysis includes the price of insulating the van, current fuel price in Serbia, as well as the average monthly temperatures in the territory of Belgrade, Serbia.
Sustainable development in waste management in the mining industry: The case of the Republic of Serbia
Authors: Stanišić Vladislav , Bošković Aleksandar
Published: May 2021

Throughout the centuries, human activities have always generated different kinds of waste, and this has become a significant problem which nowadays is considered as one of the main polluters of the environment. The term waste management is gaining importance as a way of providing an efficient solution for this problem. Data from the EU-28 shows that nearly one third of the total waste produced is attributed to mining activities. This paper focuses on the waste generated by the mining industry in the case of the Republic of Serbia. Considering that Serbia is in the process of becoming an EU member state, there are several ongoing projects which aim to enhance and reach a level of sustainable development in the respective field. As an example, a project which is currently being implemented will be covered in this research, namely - "Cadastre of mining waste".
The international legal character of genocide
Authors: Danilović Nemanja
Published: May 2021

The paper is dedicated to genocide as one of the most challenging international crimes sanctioned by both national and international laws. The paper seeks to analyze the contemporary international legal character of genocide, its basic characteristics, features, and its consequences. The main purpose and the idea of this paper is to prove, through the analysis of this international crime, the extent of harm the genocide may cause to an ethnic, religious, racial, minority, or political group, and, at the same time, to draw attention of all subjects of international public law to the necessity of taking preventive and protective measures against genocide.
Modeling a unit for the fight against terrorism on the territory of the Republic of Serbia
Authors: Radovanović Marko
Published: May 2021

The fight against terrorism is one of the most important factors that has an impact on both international and regional security and the security of the Republic of Serbia. Due to the expansion of terrorism in the world, it is necessary to establish effective mechanisms for protection against terrorism and terrorist activities. The establishment of anti-terrorist and counter-terrorist units and their modernization are key factors in the fight against terrorism. The paper analyzes the theoretical foundations of the elite antiterrorist units of the leading countries of the world, and the counterterrorism units of the Republic of Serbia. Using the AHP method in support of choosing the most effective counterterrorism unit, the conclusion was reached about the most effective counterterrorism unit in order to model an effective counterterrorism unit in the territory of the Republic of Serbia and modernize existing anti-terrorist units. Comparative analysis was carried out on the basis of criteria such as the number of members of the unit, the number of modular units, the type and level of weapons and military equipment used by counterterrorism units, the duration of selective training for entering a special unit, the duration of the training cycle of members of the unit and the average age of members of the unit. The result of this research can be implemented in anti-terrorist units in Serbia, in order to increase the efficiency of the anti-terrorist unit in the fight against terrorism. In the end, the modeling of one type of counterterrorism unit was carried out, which with its organizational-formation structure and equipment could successfully counter terrorism on the territory of the Republic of Serbia.
Citing literature
Authors: Ilić Aleksandra , Tomašević Jelena , Prelević Vasilije , Pajčin Mirjana
Published: May 2021

Publishing the results of research is the final outcome of a research paper - what has not been published is considered not to have existed. The aim of publishing research is to promote an original idea or to improve existing ideas, with the use of reliable sources. When writing different types of publications (research and professional papers, doctoral theses, books, etc.) it is necessary to state the sources that the ideas or text related to that publication were taken from. Science did not start with the authors of any individual research paper nor will it end with them - whatever the topic of the research is, there is a high probability that someone has already written something about it. If other authors' ideas or text are used in one's research, this must be stated in the text of that research. The standardized method of referring to sources is citing. Sources are cited in three ways: by quoting, paraphrasing, and summarizing. Citing sources may be direct and indirect. Sources may be referred to in the text (citing), at the end of the page (footnote), or at the end of the paper (endnote). Different sources may be cited: books, scientific journals, pictures, videos, audio sources, etc. The basic citation unit is a reference. Software for reference management enables the authors of publications to gather and organize references, insert quotes into the text, and create a bibliography. There are many such different programs. Some can be used free of charge (Mendeley, Zotero), while others must be purchased (EndNote). With the development of Internet technology, this type of software is also developing new functions in order to facilitate cooperation and networking amongst researchers, as well as to assist in the development of academic social networks. Accurate citing ensures the integrity of existing scientific knowledge that is being presented, it contributes to the reputation of a scientific journal and strengthens the credibility of the author and the research itself.
Osteoarthritis, osteoarthrosis and osteoarthropathy: What is the difference?
Authors: Jeremić Danilo , Gluščević Boris , Rajković Stanislav , Jovanović Želimir , Krivokapić Branislav
Published: May 2021

Osteoarthritis, osteoarthrosis, and osteoarthropathy are diseases that doctors encounter daily in their practice. The use of all three terms is customary, often without a clear justification as to why a particular term is used for a particular case. In the past several decades, doctors mainly differentiated among these diseases based on clinical presentation and radiography. In the past several years, however, significant progress has been made in the field of biochemical, immunological, and cytohistological research, which has provided explanations for the pathogenesis of these conditions, enabled defining differences amongst them and facilitated the use of appropriate terms for each one of these diseases. The term arthritis (osteoarthritis) should be used exclusively for primarily inflammatory joint diseases-rheumatoid arthritis, juvenile arthritis, reactive arthritis (Reiter's syndrome). If the etiology is infectious, this must also be emphasized-septic (purulent) arthritis, tuberculous arthritis. Arthrosis (osteoarthrosis) relates to changes in the joints occurring due to pathological processes within the joint itself, but which, in their basis, are not inflammatory. Arthropathy is a term for joint disease stemming from another diseased organ or system of organs.
Perinatal complications of pregnancies complicated by uterine fibroids
Authors: Sparić Radmila , Tomašević Đina
Published: May 2021

Fibroids (myomas) are the most common tumors of the female reproductive organs, consisting of smooth muscle cells, fibroblasts, and extracellular matrix. They develop from menarche to menopause. They are diagnosed in 10-20% women of reproductive age. Their size varies from barely visible nodules to large tumors. Change in the size of fibroids during pregnancy and after childbirth is the subject of numerous studies. Most studies indicate a significant increase in the size of fibroids during the first trimester, unchanged size during the second and the third trimester, and a decrease in their size after the delivery. The effect of fibroids on pregnancy depends on their number, location, and size. Myomas are associated with numerous perinatal complications: bleeding in pregnancy, miscarriages, pain due to red degeneration, preterm birth, placental abruption, placenta previa, intrauterine growth restriction, fetal malpresentation, prolonged labor, increased cesarean section rate, uterine atony, and postpartum hemorrhage. Treatment of fibroids in pregnancy includes bed rest and follow-up with symp-tomatic therapy in case of pain, as well as intensive monitoring of the fetus. Very rarely, myomectomy may be necessary during pregnancy. Myomectomy during cesarean section has been considered contraindicated for years. Recent research demonstrates that this procedure may not be associated with an increased risk of perioperative complications. Its advantages include performing two operations within one surgical procedure while avoiding the risks of repeated laparotomy and anesthesia. The most common postpartum complications of fibroids are bleeding and infection.
USS Constitution Preparations for Sail 200
Authors: Chatterton Howard
Published: May 2021

On July 21, 1997, the USS Constitution operated under sail and untethered for the first time in 116 years. This paper describes the technical effort undertaken to assure the safety of one of the nation's great historical treasures.
On-the-water Measurement of Laminar to Turbulent Boundary Layer Transition on Sailboat Appendages
Authors: Lurie E. A.
Published: May 2021

Achievement of laminar boundary layer flow over sailboat appendages offers great potential for increased boat speed. Although some measurements of turbulence intensities and length scales in the upper ocean are available, it is unclear whether the local effects of wave action, high particulate content, and boat motions, would prohibit the development of large runs of laminar flow. In order to determine whether laminar boundary layers routinely develop at full-scale conditions, the laminar-to­turbulent boundary layer transition region was measured on the keel fin and bulb of a sailboat going upwind, downwind, and under tow. The experimental approach described in this paper will be useful for the development and evaluation of various seawater drag reduction methods.
El papel del tutor en la enseñanza de la educación a distancia: una revisión sistemática sobre el enfoque de competencias
Authors: Massuga Flavia , Soares Simone , Luis Dias Doliveria Sergio
Published: May 2021

Considerando las particularidades y la importancia del papel del tutor en la Educación a Distancia, este estudio tuvo como objetivo identificar las competencias intrínsecas a las funciones de tutoría en esta modalidad de enseñanza. Para ello, se realizó una revisión sistemática utilizando la metodología Methodi Ordinatio, en las bases de datos del Portal de Revistas Capes; Scientific Electronic Library Online, ScienceDirect y Scopus, que cubre estudios centrados en el tema en los últimos 10 años. En total, 12 estudios cumplieron los criterios establecidos y fueron evaluados. Los resultados muestran competencias técnicas, gerenciales y sociales asociadas con el papel del tutor. Entre ellos, se destacan las competencias de proporcionar atención individualizada a los estudiantes, de utilizar los sistemas y conocimientos asociados con la tecnología de la información, de proporcionar un entorno en línea acogedor, amigable, confiable y estimulante, de demostrar empatía, de estimular la interacción, de motivar a los estudiantes y proporcionar realimentación. Las dificultades aún son evidentes en relación con las habilidades técnicas y sociales, lo que lleva a la necesidad de una dirección dirigida a su desarrollo y mejora, para que puedan ayudar en el desempeño práctico eficaz y eficiente del tutor.

Considering the particularities and the importance of the tutor's role in the Distance Education (EAD) modality, this study this study aimed to identify the competencies intrinsic to the tutoring functions in EAD. For this, a systematic review was carried out using the Methodi Ordinatio methodology, in the databases of Portal de Periódicos Capes; Scientific Electronic Library Online (Scielo), ScienceDirect and Scopus, covering studies focused on the theme in the last 10 years. In total, 12 studies met the established criteria and were evaluated. The results show technical, managerial and social competencies associated with the role of the tutor. Among them, we highlight the competencies of: providing individualized attention to students, using the systems and knowledge associated with information technology, providing a welcoming, friendly, trusting and stimulating online environment, demonstrating empathy, stimulating interaction, motivating students and providing feedback, which are largely directed to the social perspective. Difficulties are still evident in relation to technical and social competencies, which leads to the need for a direction aimed at their development and improvement, so that they can assist in the effective and efficient practical performance of the tutor.
POLYETHYLENE PACKAGING WITH SILVER AND ZINC MICROPATICLES AND ITS INFLUENCE ON MILK QUALITY
Authors: Rodionov Gennady V. , Olesyuk Anna P. , Koltinova Elena Ya. , Egorov Vladislav V. , Malofeeva Natalya A. , Oshchepkov Maxim S.
Published: May 2021

Protection of milk and dairy products from the effects of microorganisms and surface spoilage by the introduction of antimicrobial additives into packaging materials is a relevant and promising method. This publication is devoted to the preparation of a microparticle-modified ECOS preparation (silver salts and oxide) of a polyethylene package, the study of its properties and effects on the composition of milk. The basic physicochemical and microbiological parameters of milk during storage, as well as the possible migration of microparticles into milk and model liquids were studied by the methods of elemental analysis, scanning electron microscopy, and laser dynamic light scattering. It was found that such indicators as the content of fat, protein, lactose, dry substances remain unchanged within the experimental error for the initial milk, milk aged for 24 h in a glass container, and in contact with the modified polyethylene. When stored in glassware at room temperature (24 °C), the number of mesophilic aerobic and facultative anaerobic microorganisms in a day amounted to 8.1 · 106 CFU/cm3, while the number of bacteria in the package with ECOS was 6 times less. It was found that the silver content in milk in contact with the modified polyethylene is negligible. The amount of zinc increases within 24 h by 10%, which is not critical in terms of milk quality indicators. It is shown that storing milk in a polymer package made with ECOS preservatives allows to suppress the development of microorganisms in cow milk, does not lead to any significant change in its composition and does not affect the quality.
DECOMPOSITION OF ORGANIC DYES IN THEIR AQUEOUS SOLUTIONS UNDER ACTION OF ELECTRIC DISCHARGES OF ATMOSPHERIC PRESSURE
Authors: Manukyan Anna S. , Seyoum Mikael Belay , Rybkin Vladimir V.
Published: May 2021

This review examines the processes of degradation of organic dyes in their aqueous solutions under the action of atmospheric pressure discharges. These processes are important for solving the environmental problem associated with the purification of water from organic pollution. A brief description of the types of discharges used for these purposes is given - dielectric barrier discharge, pulsed corona discharge, gliding arc discharge, direct current glow discharge, diaphragm discharge, and contact glow discharge electrolysis. The results are given on the degree of degradation of more than 30 types of dyes in different types of discharges. The features of comparing different types of discharges in terms of their energy efficiency of the degradation process - the energy spent on the decomposition of one gram of dye - are discussed. The kinetic regularities of the decomposition process and the influence on them of various factors - the initial concentration of the dye, the discharge power, and the pH of the solution are considered. Possibilities of accelerating degradation using homogeneous and heterogeneous catalysts are discussed. Possible mechanisms of the ongoing processes and the participation in them of active particles formed in solution under the action of a discharge (OH, HO2 and ozone radicals) are analyzed.
OBTAINING HIGH QUALITY LITHIUM CARBONATE FROM NATURAL LITHIUM-CONTAINING BRINES
Authors: Ramazanov Arsen Sh. , Ataev David R. , Kasparov Miyasat A.
Published: May 2021

The aim of this work is to develop a new effective technology for producing high-quality lithium carbonate from natural lithium-containing brines. Freshly deposited aluminum hydroxide was used to separate lithium from the trace amounts of sodium and calcium. It was found that the completeness of lithium extraction from brines purified from magnesium depends on the sorbent dosage, phase contact time, mineralization, pH, and brine temperature. To extract lithium from brines with a mineralization of less than 100 g/dm3, it is necessary to introduce 4 mol of aluminum hydroxide per 1 mol of lithium in the brine. For brines with a mineralization greater than 200 g/dm3, the consumption of the sorbent providing the extraction of lithium more than 96% is 2.5 mol of aluminum hydroxide. Desorption of lithium chloride from lithium-aluminum concentrate is carried out by processing 4-5 canopies of concentrate in a Soxlet type apparatus with the same volume of distilled water. The resulting concentrated solution of lithium chloride is purified from calcium impurities in contact with a saturated solution of lithium carbonate. From a heated aqueous solution of lithium chloride purified from calcium impurities, lithium carbonate is precipitated by dosing a stoichiometric amount of a saturated solution of sodium carbonate into it. The precipitate of lithium carbonate is separated from the mother solution, washed with three portions of a saturated solution of lithium carbonate at a ratio of solid to liquid by weight equal to one to five, in order of decreasing the concentration of sodium in each portion of the wash water. The dried product contains at least 99.6% Li2CO3.
OBTAINING BIODEGRADABLE COMPOSITE MATERIALS BASED ON POLYOLEFINS AND HUSK OF SUNFLOWER SEEDS
Authors: Shabarin Alexander A. , Kuzmin Anton M. , Vodyakov Vladimir N. , Shabarin Igor A.
Published: May 2021

The paper presents the results of a comparative study of physical and mechanical, rheological, and biodegradable characteristics of a mixture containing low- and high-pressure polyethylene (HDPE 273-83 and HDPE 15303-003, respectively) in a 1:1 ratio filled with finely ground (less than 200 microns) sunflower husk (5-30% by weight). The mixture also contained 10% compatibilizer (functionalized by the method of alkaline alcoholysis of sevilen (SEVA 12206-007) and 1% of technological additive (polyethylene glycol (PEG-115 (4000). It has been established that as the content of the plant filler increases (up to 25%), the elastic modulus and tensile strength has not practically changed. The relative elongation of the composite under tension exceeds 100% (with a sunflower husk content up to 15% by weight). The complex viscosity and shear modulus of the considered melts with different filler contents are almost at the same level. The introduction of sunflower husk (up to 30%) and compatibilizer (10%) helps to reduce the viscosity and elasticity of the melts, which is evidence of a significant improvement in the processability of the compositions compared to HDPE 273-83. For a comparative assessment of composites biodegradability, moisture absorption, chemical oxygen consumption, and composites mass loss in laboratory soil during exposure for 12 months were being studied. It is shown that with increasing filler content, the ability of composites to biodegradation increases. In addition, it was found that the indicator of chemical oxygen consumption per unit surface area of the sample is a more productive and reproducible estimate in comparison with traditional methods for assessing the degradability of composite materials.
CATALYTIC CONVERSION OF ETHYLENE ON SYSTEMS BASED ON THRICHLOROTRIS-(TETRAHYDROFURANATE)CHROMIUM(III) WITH SOS-TYPE LIGANDS IN COMBINATION WITH VARIOUS ORGANOALUMINUM COCATALYSTS
Authors: Babenko Ilya A. , Bezborodov Viktor A. , Vilms Alexey I.
Published: May 2021

This work presents the results of studying the behavior of catalytic systems formed on the basis of trichlorotris-(tetrahydrofuranate)chromium(III) in the presence of sulfur-containing tridentate SOS-type ligands and activated by various organoaluminum compounds. In the formation of catalytic systems, the following compounds were used: SOS-type ligands - bis-(2-methylthioethyl) ether, bis-(2-ethylthioethyl) ether and bis-(2-phenylthioethyl) ether, organoaluminum compounds - triethylaluminum, triisobutylaluminum, tributylaluminum and methylaluminoxane. In the course of test experiments aimed at choosing an activator at a temperature of 40 °C and an ethylene pressure of 2 MPa, the best results were obtained for triethylaluminum. Therefore, further experiments on the catalytic conversion of ethylene were carried out only with this activator. To study the effect of the reaction temperature and ethylene pressure in the reaction zone, catalytic systems of the trichlorotris-(tetrahydrofuranate)chromium(III)/ligand/triethylaluminum composition were studied in the temperature range from 40 to 80 °C and an ethylene pressure of 2 - 3 MPa with a molar ratio of components Cr : L : AlEt3 = 1 : 1 : 20. As a result of studies, it was shown that in all cases when using tridentate ligands of the SOS type, the catalytic systems formed by us showed a tendency not only to polymerization, but also to oligomerization of ethylene. The best results in the field of ethylene oligomerization into hexenes were shown by the system of the composition trichlorotris-(tetrahydrofuranate)chromium(III) / bis-(2-methylthioethyl) ether/triethylaluminum, in which the content of the hexene fraction is 54 - 55 wt.%, while the selectivity to hexene-1 reaches 88 - 89%.
EFFECT OF MAGNETIC FIELD ON RHEOLOGICAL PROPERTIES OF CELLULOSE ETHERS SOLUTIONS
Authors: Soliman Tarek Salekh Attia , Rusinova Elena V. , Vshivkov Sergey A.
Published: May 2021

The rheological properties, structure and phase transitions of hydroxypropyl cellulose in ethanol, dimethyl sulfoxide, ethylene glycol solutions and ethylcellulose in dimethylformamide solutions are studied using viscometry, the cloud-point method, polarization microscopy, the optical interferometry and a polarization photoelectric apparatus in the temperature range 280-360 K. The temperature-concentration regions of isotropic and anisotropic phases are determined for all systems. The type of boundary curves of phase diagrams is compared with the chemical structure of macromolecules. It is shown that the constant magnetic field (3.6 kOe) leads to the orientation of macromolecules in solutions. The domain structure arising in solutions is fixed after evaporation of a solvent and shown in orientation of strips of the film relief. It was found that the flow curves of all solutions at 298 K in the range of shear rates from 0 to 15 s-1 are typically for the non-Newtonian liquids. It was found that the magnetic field leads to an increase in the viscosity of isotropic solutions and a decrease in the viscosity of anisotropic solutions. Both effects depend on the direction of the magnetic field lines. When the rotor-rotation axis is parallel to the direction of power lines of the magnetic field the change in the viscosity of solutions is greater than that at perpendicular orientation of the rotor-rotation axis and power lines of the magnetic field. The results are discussed using representations about the changes in the macromolecule conformation and in the size and shape of the supramolecular particles in the solutions during flow under a magnetic field with different orientation of the power lines.
DISTRIBUTION OF THORIUM (IV) IONS IN AQUEOUS EXFOLIATING SYSTEM CONTAINING ANTIPYRINE AND SULFOSALICYLIC ACID
Authors: Degtev Mikhail I. , Yuminova Aleksandra A.
Published: May 2021

The possibilities of an aqueous delaminating system containing antipyrine (AP) and sulfosalicylic acid (SSA) for extracting macro - and microamounts of thorium (IV) were studied. The proposed extraction system eliminates the use of toxic organic solvents. The dependences of the distribution of metal from nitrate solutions between phases on the concentration of reagents, acidity of the medium, the amount of inorganic salting-out agent (NaNO3, NH4NO3, Na2SO4) and the volume of the aqueous phase are determined, and optimal conditions for extraction are found. It is shown that in the organic phase with a volume of 1.6 ml at room temperature, macro-and microamounts of thorium (IV) are extracted by 88 and 90%, respectively. The maximum extraction of the cation is achieved at the ratio of AP: SSA = 2.0 : 1.0 and their concentration, mol/l: 0.6: 0.3, while the acidity of the medium created by nitric acid should be equal to 0.015 mol/l (pHequ. = 1.8-1.9). The extraction of thorium (IV) becomes quantitative if inorganic salts (sodium sulfate, sodium nitrate) are introduced into the AP – SSA – 0,015 mol/l HNO3 – H2O system, which, by reducing the activity of water, increase the concentration of reagents in the aqueous phase. The concentration of salting-out agents should correspond to 1.0 and 2.5 mol/l. A mechanism for the distribution of a mixed thorium (IV) complex containing AP, SSA, nitrate ions, solvated with a salt of antipyrinium sulfosalicylate is proposed. The extract is mixed in any relationship with distilled water, providing the use of various instrumental methods of analysis. A method for extraction-photometric determination of thorium (IV) with a toron indicator has been developed. The limit for the fulfillment of the Bouguer-Lambert-Beer law is established. The apparent coefficient of light absorption is calculated (ε = 1.7∙104).
HIGHLY EFFICIENT REMOVAL OF COPPER(II) IONS FROM AQUEOUS SOLUTION BY NICKEL 2-ETHYLIMIDAZOLATE
Authors: Fufaeva Victoria A. , Filippov Dmitry V.
Published: May 2021

Nickel 2-ethylimidazolate was obtained and characterized, which is used in this work as a sorbent for the removal of copper (II) ions. The sample characterization was carried out by scanning electron microscopy, low-temperature nitrogen adsorption. It was found that the obtained sorbent is a microheterogeneous material with the size of individual particles in the range of 0.4-0.7 μm. Nitrogen adsorption isotherms in the pores of nickel 2-ethylimidazolate were obtained. It was found that when processing the experimental data in linear coordinates of TVFM, linearization is reached in coordinates lnV-lnPs/P, which indicates the predominance of mesopores in the structure of nickel 2-ethylimidazolate. The total pore volume was determined from the TVFM linear coordinates. It was 0.21 cm3/g. According to obtained differential pore size distribution, the most probable average pore radius corresponds to 7.5 nm. One of the main characteristics of nickel 2-ethylimidazolate as a sorbent, the surface area was determined by the A.V. Kiselev method and amounted to 703.56 m2/g. The efficiency verification of using nickel 2-ethylimidazolate in the heavy metal ions sorption processes was carried out by removal of copper(II) ions from aqueous solutions by the limited solution volume method at different contact times. The copper(II) sorption kinetics in the presence of nickel 2-ethylimidazolate was studied by processing experimental data in the first and second orders linear coordinates. It was found that the adsorption kinetics of copper(II) ions is described by a second order model, which indicated ion-exchange adsorption. Equilibrium adsorption capacity in the sorbent-solution system is reached at a contact time of 90-120 min.
ANALYSIS OF POLYESTERS STRUCTURE BASED ON MALIC ACID AND ITS ESTER
Authors: Kuzmina Natalia S. , Portnova Svetlana V. , Krasnykh Eugen L.
Published: May 2021

Four polyesters based on malic acid and its dibutyl ester were obtained. Ethylene glycol and 1,4-butanediol were used as comonomers. The reaction of polycondensation was carried out without a catalyst, and the transesterification of glycol esters was carried out in the presence of tetrobutoxytitanium in an amount of 1wt%. The malic acid during polycondensation we melted and dissolved in glycols at a temperature of 100 °C to prevent the reaction of intramolecular dehydration. The reactions were carried out for 3 hours with stirring and gradual heating of the reaction mass. The processes were carried out in a flow of nitrogen to remove the formed low-molecular products. These products were condensed and analyzed by gas-liquid chromatography. The control of the polycondensation reaction was carried out by the molecular weight determined by the viscometric method. The structure of the obtained polyesters was determined using IR and (1H, 13C) NMR spectroscopy. The obtained polymer samples represent a resinous mass from light yellow to light brown with average molecular weights from 2000 to 4000 g/mol. Analysis of IR spectra showed that in the samples obtained by ester transesterification, the intensity of the hydroxyl group band is more than that of acid and diol based polymers. This difference can be explained by the presence of polymer chain branches obtained as result of the reaction of self-condensation. Analysis of (1H, 13C) NMR spectra confirms that in the process of polycondensation of malic acid with diols, a side reaction of self-condensation of the acid occurs with the formation of branched polymer units. In the case of the use of an ester as a monomer, polyester of a linear structure is obtained. In all obtained samples of polyesters, the presence of unsaturated bonds in the structure was also observed. This confirms that a side reaction of internal malic acid dehydration took place under the synthesis conditions. To reduce the unsaturation of polyesters, the polycondensation process must be carried out at a lower temperature.
STUDY OF PROPERTIES OF ISOPRENE OLIGOMERS OBTAINED BY MICROWAVE IRRADIATION OF SKI-3 RUBBER
Authors: Tsyganova Marina E. , Rakhmatullina Alevtina P.
Published: May 2021

The present article proposes a method for production of low molecular weight rubber in microwave irradiation field. Isoprene rubber SKI-3 (10% solution in toluene) was used as the initial reactant. The effect of MWI power change (144 W, 450 W, 675 W, 900 W) on the degree of destruction was studied. The degree of destruction was measured based on the change in viscosity average molecular weight. The findings of the experiment data analysis indicate that the destruction process occurs in correspondence with the following dependency: the increase in the microwave irradiation power raises the destruction degree. At the same time, a decrease in molecular weight was observed. Furthermore, it was found that the use of phospholipids as modifiers also affects the destruction process. The increase in phospholipids content in toluene-SKI-3 system reduces the degree of polyisoprene destruction regardless of the microwave irradiation power. It is demonstrated by the fact that rubber molecular weight is subject to a lower decrease in systems with higher phospholipids content. Phospholipids perform two functions. Firstly, they act as a stabilizer that inhibits the rubber destruction process. Secondly, varying their content allows controlling the destruction degree and obtaining oligomers with predetermined molecular weight. The obtained oligomers were used as SKI-3 isoprene rubber modifiers. It is observed that that the introduction of oligomers into rubber mixtures in the amount of 7 and 10 parts by weight per 100 parts by weight of rubber increases its cohesive strength. Furthermore, vulcanizates containing oligomers are characterized by improved physical and mechanical properties.
APPLICATION OF SUPERCRITICAL EXTRACTION FOR ISOLATION OF CHEMICAL COMPOUNDS
Authors: Menshutina Natalya V. , Artemiev Artem I. , Khudeev Illarion I. , Kazeev Ilya V. , Bocharova Olga A.
Published: May 2021

This paper provides a review of the scientific literature on the study of the supercritical extraction process. The use of substances in a supercritical state as an extractant is the basis of the supercritical extraction process. In a supercritical fluid, there is a high intensity of mass transfer, which allows the supercritical fluid to easily penetrate into the raw material and efficiently extract the target components. Carbon dioxide is of particular interest, since its use as an extractant in the process of supercritical extraction meets the basic principles of «green chemistry». The paper presents the mechanisms of mass transfer of target components from plant raw materials that arise during the process of supercritical extraction using carbon dioxide. The kinetics of the supercritical extraction process is considered. During the process, three main periods are distinguished: a period of a constant extraction rate, a period of a falling extraction rate, and a period of a low extraction rate. The influence of temperature and pressure, the influence of water in the raw material on the yield of target components in the process of supercritical extraction is shown. Supercritical extraction requires special high-pressure equipment. The paper presents the main technological solutions for the implementation of the process. A comparison of the process of supercritical extraction with extraction in the Soxhlet apparatus is carried out. The supercritical extraction process makes it possible to obtain an extract of high purity, which is promising for the production of biologically active medicinal components and the separation of impurities from difficult-to-separate mixtures. Examples of the application of supercritical extraction in industry are given. In addition, the paper presents studies on the extraction of aralosides from Aralia mandshurica plant raw materials using the supercritical extraction process. Supercritical extraction is considered as a safe and more efficient way to extract target components from plant materials.
Eyelid discoid lupus erythematosus
Authors: Khallaayoune Mehdi , Belmourida Siham , Azzahra Elgaitibi Fatima , Meziane Mariame
Published: May 2021

Discoid lupus erythematosus (DLE) most commonly affects the face and scalp. Palpebral involvement is rare and not evocative when presenting as the prime manifestation of the disease. We report hereby the case of a young male patient with isolated palpebral and labial DLE. A 34-year-old patient with no medical history was referred from ophthalmology for an erythematous plaque of the eyelid resisting usual treatment of blepharitis. Skin examination revealed a congestive erythema on the right lower eyelid with eyelash fall (Fig. 1). There was also an atrophic cheilitis of the lower lip with slight erosions (Fig. 2). Scalp, oral mucosa and the rest of the integument were not affected. Skin biopsy of the eyelid revealed marked orthokeratosis with slight basal vacuolization and perivascular lymphoplasma cells infiltrate. Direct immunofluorescence displayed a positive lupus band (Fig. 3). Work-up for systemic involvement was negative. Ophthalmologic assessment found no intraocular involvement. Hydroxychloroquine 200mg twice a day with clothing and chemical photoprotection were implemented allowing significant improvement after 3 months (Fig. 4). Palpebral involvement of DLE is uncommon compared to the other suggestive locations including scalp, nose, cheekbones, ears, neckline and hands. An isolated involvement does not suggest DLE at first sight and often leads to delayed diagnosis while scarring and lid deformities might be expected if left untreated [1]. Most commonly it presents as erythematous telangiectasic scaly plaques on the external third of lower eyelid. Blepharitis-like, madarosis, periorbital edema or cellulitis presentations have also been reported [2]. Differential diagnosis may arise with several chronic palpebral dermatoses, as carcinomas, eczema, blepharoconjunctivitis, or seborheic dermatosis. Assessment for intraocular involvement such as keratitis should always be performed [3]. Early recognition and treatment are essential to avoid eyelid complications as ectropion, entropion, and trichiasis. Photoprotection and antimalarials are the mainstay treatment showing remarkable efficacy.
Vulvovaginal lichen planus: A case report
Authors: Nandakishore Singh Th. , Kago Yaku , Kongbam Linda , Bachaspatimayum Romita
Published: May 2021

Genital lichen planus (LP) forms a small but significant proportion of non-venereal genital dermatoses. Lesions of vulvovaginal LP are often asymptomatic and may be overlooked on self-examination. Clinical features are very similar to lichen sclerosus which is frequently seen in children whereas mucosal vulval LP commonly affects adult females. Histopathological examination of the lesion is an important diagnostic tool for its early diagnosis as progressive disease poses a risk of scarring. We report a case of vulvovaginal LP in a 56-year-old postmenopausal female presenting with hypopigmented patches on vulva for 10 years.
Pyogenic granuloma under nail: A rare localization
Authors: Oulehri Aida , Douhi Zakia , Acheboune Kaoutar , Baybay Hanane
Published: May 2021

Pyogenic granuloma (PG) – also known as lobular capillary hemangioma – is a benign vascular tumour that occurs on the skin and mucous membranes, it’s can arise spontaneously, in sites of injury, or within capillary malformations [1]. Because malignant tumors, such as amelanotic melanoma, can be misdiagnosed as PG, histopathology is mandatory for the correct diagnosis, even though dermoscopy can play a primary role in the prompt recognition of PG, showing highly repetitive patterns that can support the diagnosis [2]. In particular, the presence of reddish homogeneous area, white rail lines are strongly suggestive of PG; even more so when associated together. On the other hand, with dermoscopy, it is not uncommon to detect ulceration and vascular structures that do not rule out malignancies [3]. Vascular structures are observed in 45% of cases, they can be linear-irregular or polymorphic and atypical [2]. Despite its benign nature, GP can have a significant negative impact on patients’ quality of life, and therefore appropriate therapy is needed. This is a 35-year-old patient with a history of trauma to his left hand dating back 3 months before his admission. He presents with a nodule under his left thumb, which has been evolving for 2 months, fixed in depth and sometimes-bleeding (Fig. 1). The nodule was slightly painful. X-rays of the thumb were normal. On dermoscopy (Fig. 2), we noted the presence of vascular lagoons with fibrous septal and linear vessels. We suspected a botryomyoma or achromic melanoma. Surgical excision was performed (Fig. 3) with an anatomopathological study in favour of a pyogenic granuloma.
On the Geometry of Submersions
Authors: Narmanov Abdigappar , Sharipov Xurshid
Published: May 2021

Subject of present paper is the geometry of foliation defined by submersions on complete Riemannian manifold. It is proven foliation defined by Riemannian submersion on the complete manifold of zero sectional curvature is total geodesic foliation with isometric leaves. Also it is shown level surfaces of metric function are conformally equivalent.
Star Product on the Euclidean Motion Group in the Plane
Authors: Natividad Laarni B. , Nable Job A.
Published: May 2021

In this work, we perform exact and concrete computations of star-product of functions on the Euclidean motion group in the plane, and list its $C$-star-algebra properties. The star-product of phase space functions is one of the main ingredients in phase space quantum mechanics, which includes Weyl quantization and the Wigner transform, and their generalizations. These methods have also found extensive use in signal and image analysis. Thus, the computations we provide here should prove very useful for phase space models where the Euclidean motion groups play the crucial role, for instance, in quantum optics.