bluuebunny/crossref_metadata_2025 huggingface dataset:
Water quality assessment and physicochemical parameters of groundwater in District Hapur, Uttar Pradesh, India
Authors: Mohan Udit , Singh Randhir , Singh Prem
Published: March 2021

The present study investigation of the ground water contamination of Hapur district (U.P.), India has been carried out. The ground water samples were collected from different locations from hand pumps mark II in Hapur district.Water Quality Index (WQI) of drinking water has been assessed by using various physicochemical & biological parameters for the ground wateranalysis. Water samples were analysed using various physicochemical and biological parameters such as pH, Electrical Conductivity, Total Dissolved Solid, Total Hardness, Chloride, Fluoride, Nitrate, Sulphate, Total Acidity, Total Alkalinity, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD) and Dissolved Oxygen (DO)etc. and the results compared with the standards given by WHO, ICMR and BISThe correlation between different parameters was also assessed. The average values of physicochemical and biological parameters were observed as pH 7.86, Electrical conductivity 1206.67mmhos/cm, TH 734.17 mg/l, acidity 352.08 mg/l, total alkalinity 464.17 mg/l, TDS 645.17 mg/l, chloride 85.50mg/l, fluoride 0.77 mg/l, nitrate 45.99 mg/l, sulphate 160.39 mg/l, COD 12.79 mg/l, DO 4.08 mg/l and BOD 1.99 mg/l respectively. The WQI of different blocks of district Hapur reveals that the water quality is poor for drinking and other activities.
Chemical composition, antioxidant, antimicrobial activity, toxicity, genetic analysis and popular use of Eugenia luschnathiana(O. Berg) Klotzsch ex B.D.Jacks: a literature review
Authors:   Federal University of Paraíba, Henriques Martha Quiteria Silva , Barbosa David Henrique Xavier ,   Federal University of Paraíba, Alves Danielle da Nobrega ,   Federal University of Paraíba, Melo Ana Karoline Vieira ,   Federal University of Paraíba, Dias de Castro Ricardo ,   Federal University of Paraíba
Published: March 2021

This review describes the geographical distribution, botanical data, popular use, chemical composition, pharmacological activities and genetic aspects related to Eugenia luschnathiana, a native Brazilian plant popularly known as “bay pitomba”. E. luschnathianaleaves are characterized morphologically by the presence of a petiole, an attenuated base, acuminated apex, elliptical shape, and parallel venation. The major chemical compounds found in E. luschnathiana are sesquiterpenes. Literature reports showed that E. luschnathianaextracts have antioxidant properties and antimicrobial activity against Gram-negative and Gram-positive bacteria. The extractsfrom the leaf, fruit and stem, and a concentrated residual solution of its essential oil, displayed negligible toxicity. Lastly, a cytogenetic analysis indicated that some markers can be used for the study of genetic diversity, population structure, and genetic improvements. The information available on E. luschnathianasupports the hypothesis that this plant may be a source of compounds with promising pharmacological activity.
Entwicklung neuer Nachweiskonzepte für vertikale Schienenstützpunktkräfte an Bauwerksfugen bei Fester Fahrbahn mithilfe von Grenzwertbetrachtungen/Development of new design concepts for vertical rail support forces on bridging joints with slab track by means of limit value consideration
Authors: Vogel M. , Schramm N. , Plica S. , Fischer O.
Published: March 2021

Bei Oberbauten mit Fester Fahrbahn müssen die vertikalen Schienenstützpunktkräfte im Bereich von Bauwerksfugen nach aktuellem Stand der Technik gemäß den Angaben der Anlage 29 der DS 804 nachgewiesen werden. Aufgrund des nicht-linearen Steifigkeitsverhaltens neu entwickelter Sonderstützpunkte für Brücken sind die auf linearen Steifigkeiten basierenden Regelungen der im Jahr 2000 veröffentlichten Anlage 29 kritisch zu hinterfragen.

 

Im vorliegenden Beitrag werden sowohl die Grundlagen als auch die Ermittlung und die Auswertung von sogenannten j-d-Diagrammen vorgestellt, welche über lineare und nicht-lineare Grenzwertbetrachtungen hergeleitet wurden. Mithilfe der Diagramme kann eine Bewertung des aktuell gültigen Nachweisformates erfolgen. Gleichzeitig wird durch die dargestellten Grenzräume eine vereinfachte Bestimmung der zulässigen Bauwerksverdrehungen und -verformungen ermöglicht.
Evaluationen zu den Potenzialen von Building Information Modeling/Evaluations on the potentials of Building Information Modeling
Authors: Bahlau S. , Klemt-Albert K.
Published: March 2021

Bauprojekte weisen aufgrund ihrer multidimensionalen Komplexität häufig Zielverfehlungen auf. In zunehmenden Maße werden nun Digitalisierungsmaßnahmen für das Bauwesen diskutiert. Insbesondere in der Implementierung digitaler Methoden wie Building Information Modeling (BIM) wird ein wichtiger Ansatz gesehen, um die Komplexitäten bei der Projektabwicklung zu reduzieren und zu beherrschen. In der vorgestellten Studie werden auf Basis von Literaturstudien, leitfadenbasierten Interviews und Onlinebefragungen sowohl Dimensionen der Komplexität betrachtet als auch digitale Lösungsansätze durch Experteneinschätzungen bewertet. Die multidimensionale Komplexität lässt sich dabei in Kommunikation, Projektmanagement, Projektkultur und Technik clustern. Die Studie kommt im Weiteren zu einer positiven Aufwand-Nutzen-Einschätzung für verschiedene Anwendungsfälle und zeigt die Potenziale unterschiedlicher digitaler Lösungsansätze auf.
Das Seilnetzdach der Schierker Feuerstein Arena im Harz Teil 2: Herstellung, Montage und Schweißsimulation/The cable net of Schierker Feuerstein Arena at the Harz mountain rangePart 2: Manufacturing, assembly and welding simulation
Authors: Zebinger M. , Gierat M. , Pasternak H. , Krausche T.
Published: March 2021

Die Stadt Wernigerode in Sachsen-Anhalt errichtete im Ortsteil Schierke eine Multifunktionsarena. Am Fuße des Brockens, dem höchsten Berg des Harzes und ganz Norddeutschlands gelegen, fügt sich die offene Überdachung in die vorhandene Topologie nahtlos ein. Das unter Denkmalschutz stehende Natureisstadion, mit seinen bestehenden Natursteinterrassen und einem Schiedsrichterturm aus Holz, wurde baulich so konzipiert, dass die Arena in den Wintermonaten als überdachte Kunsteisbahn und im Sommer als Fläche für Konzerte, Aufführungen und Sportveranstaltungen genutzt werden kann. Eine ganz besondere Herausforderung war die Herstellung und Montage des circa 190 m langen geschweißten Stahlrandträgers. Der Hohlkasten besteht aus vier doppelt gekrümmten Blechen und lagert an lediglich zwei Fußpunkten auf. Der zweite Teil des Beitrags befasst sich mit Schweißeigenspannungen an einem ausgewählten Querschnitt der Überdachung.
Ermüdungsuntersuchungen an Verbundträgern mit Verbunddübelleisten und nachgiebiger Verbundfuge mittels Stabwerkmodellen/Fatigue investigations on composite beams with composite dowels and flexible composite joint using framework models
Authors: Wolters K. , Feldmann M.
Published: March 2021

Im Verbundbrückenbau werden neben Kopfbolzendübeln immer häufiger Verbunddübelleisten verwendet, die in Deutschland bauaufsichtlich zugelassen sind. Mit dem aktuellen Ermüdungskonzept sollen Ermüdungsschäden von Stahl und Beton vermieden werden. Hinsichtlich der positiven Ermüdungseigenschaften der Verbunddübelleiste in Klothoidenform birgt die Berücksichtigung von Ermüdungsschäden einzelner Verbunddübel, die zu einer Umverteilung der Dübelkräfte hin zu weniger belasteten Verbunddübeln im Verbundträger führt, große ökonomische Potenziale.

 

Die Ermüdungsuntersuchung von Verbundträgern mit Finite-Elemente-Programmen gestaltet sich aufgrund der hohen Lastwechselzahlen schwierig, da schon die Rechenkapazität einer einzelnen Belastungssimulation enorm ist. Daher wird in diesem Beitrag ein Stabwerkmodell mit nichtlinearen Federn vorgestellt und validiert, welches die Ergebnisse der FE-Berechnung im Bruchteil einer Sekunde reproduzieren kann. Mit diesem Modell ist es möglich, eine Vielzahl an Lastwechseln zu simulieren, Umlagerungseffekte zu berücksichtigen und die Grundlage zur Herleitung eines ökonomischeren Ermüdungskonzepts zu schaffen.
Substituted Nitrogen-Bridged Diazocines
Authors: Lentes Pascal , Rudtke Jeremy , Herges Rainer
Published: March 2021

Novel nitrogen bridged diazocines (triazocines) were synthesized that carry a formyl or an acetyl group at the CH2NR- bridge and bromo- or iodo substituents at the distant phenyl ring. The photophysical properties were investigated in acetonitrile and water. As compared to previous approaches the yields of the intramolecular azo cyclizations were increased (from ~40 to 60%) by an oxidative approach starting from the corresponding aniline precursors. The Z→E photoconversion yields in acetonitrile are 80-85% and the thermal half-lives of the metastable E configurations are 31-74 min. Particularly, the high photoconversion yields (~70%) of the water-soluble diazocines are noteworthy, which makes them promising candidates for applications in photopharmacology. The halogen substituents allow further functionalization via cross-coupling reactions.
Meningkatkan Motivasi Belajar dan Hasil Belajar Siswa Melalui Penggunaan Model Pembelajaran Tematik Pada Mata Pelajaran IPS Di Kelas II SDN 4 Kabila Kecamatan Kabila Kabupaten Bone Bolango
Authors: Abdullah Marlina
Published: March 2021

Penelitian ini bertujuan untuk meningkatkan motivasi belajar dan hasil belajar siswa melalui penggunaan model pembelajaran tematik pada mata pelajaran IPS di kelas II SDN 4 Kabila Kecamatan Kabila Kabupaten Bone Bolango dengan jumlah siswa sebanyak 22 siswa terdiri dari 9 siswa laki-laki dan 13 siswa perempuan. Sebagai kesimpulan dari penelitian ini adalah : Penggunaan Model Pembelajaran Tematik telah meningkatkan Motivasi dan Hasil Belajar Siswa pada mata pelajaran IPS khususnya di kelas II SDN 4 Kabila Kecamatan Kabila Kabupaten Bone Bolango. Hal ini didukung dengan hasil pengujian: 1) Hasil Pengamatan motivasi belajar siswa yang termasuk pada kriteria sangat baik dan baik meningkat dari 41,66% pada pelaksanaan siklus I menjadi 91,66% pada pelaksanaan siklus II, 2) Hasil pengamatan kegiatan guru yang termasuk pada kriteria sangat baik dan kriteria baik meningkat dari 47,36% pada pelaksanaan siklus I meningkat menjadi 100% pada pelaksanaan siklus II, dan 3) Jumlah siswa yang memperoleh nilai minimal 75, meningkat dari 36,36% pada observasi awal menjadi 59,09% hasil pelaksanaan siklus I, dan meningkat lagi menjadi 95,45% hasil pelaksanaan siklus II.
Inter-Laboratory collation testing as a method of improvement of objectivity of technical expertise
Authors:   St. Petersburg State Chemical-Pharmaceutical University, Belyaev Alexey P.
Published: March 2021

The results of the interlaboratory comparison tests of experimental laboratories that analyzed vodka produced and sold in the Russian Federation for human consumption are presented in order to demonstrate the capabilities of the comparison tests. The choice of vodka as a model object was determined, on the one hand, by its definite proximity to medicinal substances, and on the other, by its assignment as food product, for which the regulatory framework for interlaboratory comparison tests was developed in sufficient detail. The following controlled indicators were examined: strength, alkalinity, mass concentration of acetaldehyde, mass concentration of acetic aldehyde, mass concentration of fusel oil, mass concentration of esters (methyl acetate, ethyl acetate), volume fraction of methyl alcohol in terms of anhydrous alcohol. 30 experimental laboratories are involved in the interlaboratory comparison tests. All participants guided by the same regulatory documents. The test results are processed statically in accordance with the regulatory framework developed for food products. It demonstrated that the majority of participants in the interlaboratory comparison tests successfully coped with the task of testing vodka under the conditions of reproducibility of the analytical method, and recommendations were made to correct the activities of testing laboratories for the rest. The diagrams were constructed to demonstrate visually checks on the quality of tests in determining strength, in determining alkalinity, in determining the mass concentration of acetic aldehyde, in determining the mass concentration of fusel oil and in determining the volume fraction of methyl alcohol in terms of anhydrous alcohol. The results of statistical processing allowed to state that interlaboratory comparison tests correctly and visually assess the competence of the activities of experimental laboratories, allow to plan actions preventive violations in the objectivity of the work of experimental laboratories. It is shown that the introduction of the practice of experimental laboratories working in the field of production and circulation of medicinal substances, interlaboratory comparison tests can be one of the possible ways to improve the quality of medicinal substancesThe opinion was expressed that for testing interlaboratory comparison tests in the production and circulation of medicinal substances one can use the regulatory framework developed for food products.
Investigation of antibacterial resistance of aliphatic quarterly ammonium salts in polyrethane dispersions
Authors:   Kazan National Research Technological University, Zhukova Irina V. , Girfanutdinov Azat A. ,   Kazan National Research Technological University, Gataullin Bulat F. ,   Kazan National Research Technological University, Golovanova Ksenia V. ,   Kazan National Research Technological University, Vdovina Tatiana V. ,   Kazan National Research Technological University, Akchurina Rozalia F. ,   Kazan National Research Technological University, Tabachkov Alexander A. ,   Kazan National Research Technological University
Published: March 2021

In this work we investigated the possibility of using different structures of biocides to detect the stability of dispersion and the antibacterial properties of polyurethane water-dispersion coatings to combat the negative impact on materials, bio-damage, which can affect the quality of the human environment. This allows the use of polyurethane aqueous dispersions, where the constancy of aseptic conditions of quality is combined with good properties of polyurethane coatings. The oasheaters have been used in the first year of the 19th century to reduce the number of people. Coatings used dispe6rsionnye water-based polyurethane dispe6rsii complex poliefrov different structure (polietilenglikoladipinat, polietilenbutilenglikoladipinat, and polibutilenglikoladipinat polidietilenglikoladipinat) 2,4-diisocyanate, ionic agent and chain extenders, at a concentration of dry matter of 20-50% by weight. One of the most commonly used methods for determining the activity of antimicrobial agents is the method of diffusion of substances into agar. Evaluation of the activity of antimicrobial agents by this method is carried out according to the diameter of the zone of inhibition of growth of microorganisms (Escherichia Colli and Bacillus subtilis) on the surface of the substrate. As a result of the research, it was revealed that the actions of the used antimicrobial agents can be arranged in the following order: alkyltrimethylammonium chloride > didecyldimethylammonium chloride > dialkyldimethylammonium chloride. Maximum concentrations of biocides were found at which polyurethane dispersions are stable and do not coagulate: for quaternary amine compounds with one alkyl, the maximum permissible concentration is 10%, with dialkyl the maximum permissible concentration is 7.5%, with trialkyl the maximum permissible concentration is 3%. The increase in the diameter of the suppression of the growth of microorganisms is also influenced by the concentration of the polyurethane dispersion, which makes it possible to introduce antibacterial compounds much more.
Chemical bath synthesis of metal chalcogenide films. Part 40. Influence of hydrochemical deposition conditions of ZnS films by thioacetamide on their thickness and morphology
Authors:   Ural Federal University Named after the First  President of Russia B.N. Yeltsin, Maskaeva Larisa N. , Zhdanova Anna I. ,   Ural Federal University Named After the First  President of Russia B.N. Yeltsin, Markov Vyacheslav F. ,   Ural Federal University Named After the First  President of Russia B.N. Yeltsin, Kutyavina Anastasia D. ,   Ural Federal University Named after the First  President of Russia B.N. Yeltsin
Published: March 2021

ZnS thin films are promising as a buffer layer in solar cells; photovoltaic cells, photoelectric sensors, light-emitting diodes are being developed on their basis. In this work, the growth kinetics of ZnS films has been studied during hydrochemical precipitation with thioacetamide from acidic (biphthalate, acetate) and alkaline (ammonia) aqueous solutions. From the biphthalate bath at pH = 2.5–3.0 at 343 K and from the ammonia reaction mixture at 293 K on glass substrates, mirror layers of zinc sulfide with a thickness of up to 250 and 330 nm were obtained, respectively. The maximum thickness of the ZnS films from the ammonia system is achieved by increasing the ammonia content in it to 5 mol/l. For all the ammonia concentrations used, an extreme dependence of the thickness of the ZnS films on the concentration of thioacetamide in the system was established. When precipitating ZnS films from the acetate system, lowering the pH of the solution from 5.0 to 4.5 increases their thickness by a factor of 1.5-2.0. On the kinetic curves of changes in the thickness of the ZnS films during deposition from the biphthalate system, an area is distinguished, which is characterized by the presence of a plateau, which presumably corresponds to the sulfidization process of the zinc hydroxide phase formed at the initial stage of synthesis. The optimal composition of the reaction mixtures and the recommended time of deposition of ZnS films from the studied reaction mixtures are proposed. According to electron microscopy, the main structural elements of the zinc sulfide films precipitated with thioacetamide, regardless of the composition of the reaction mixture, are globular aggregates. The layers precipitated from the biphthalate reaction mixture have more uniform microstructure with a predominant particle size of 30-50 nm. Films obtained from the ammonia reaction mixture are formed from globules with a diameter of from 0.5 to 5.0 μm with particles of ~ 100 nm interspersed. The content of the main elements (Zn, S) in the ZnS films obtained from the biphthalate and ammonia reaction mixtures, according to the data of energy dispersive microanalysis, was 49.48, 50.52 and 50.35, 49.65 at.%, respectively.
Probabilistic and dynamic colloid equations
Authors:   South Ural State University (National Research University), Markov Boris A. , Sukharev Yury I. ,   Chelyabinsk State University
Published: March 2021

We obtained two equations that characterize the structure of the colloid: the equation of the Schrodinger type that specifies the redistribution of heat and potential energy in the colloid and material equation – the diffusion equation with the operator of Liesegang associated directly with a substance that allows you to find the discontinuities of the structures caused by the vibrations of electrically charged particles. This procedure based on the assumption of the instability of the colloidal state, caused by the movement of charged particles. The reality is not collected in parts from the particles of matter in the course of evolution from the past to the future, and is all at once from the past to the future for a given pattern, that is, for specific PATTERNS, as defined by quantum theory. Without going deep into the theory of Kulakov, we will accept its fundamental provisions as a certain given. The forms of this structural data were obtained experimentally and mathematically confirmed. Let there be a certain angle of the skeleton, where due to the unevenness and partial randomness of the structure of the core grids forms "defects" – that is, electrical or magnetic moments of a particular order. Then small mobile clusters are attracted to it by electrostatic or electromagnetic forces, which are then adsorbed and somehow arranged on the "defects" in accordance with their dipole moments. This circumstance can be determined by "magic numbers", that is, as the number of clusters "stuck" to the defect of the core structure, with the formation of chemical bonds in the future. We can assume that the spanning structure of Coxeter can form small clusters form regular polyhedrons, and may occur or other structure having more complicated form.
Quantum-chemical modeling of structure and properties of nitrogen derivatives of phloroglucinol
Authors:   Peoples' Friendship University of Russia  (PFUR University), Ryabov Mikhail A. , Anh Vu Thi Ngok ,   Peoples' Friendship University of Russia  (PFUR University), Kovalchukova Olga V. ,   Peoples' Friendship University of Russia  (PFUR University), Gusarov Dmitry S. ,   A.N. Kosygin Russian State University (Technology. Design. Art)
Published: March 2021

The DFT/B3LYP quantum-chemical method has been used to simulate the structure of 2-((2-hydroxyphenyl) diazonyl) benzene-1,3,5-triol (L1) and 2-((2-hydroxy-4-nitrophenyl) diazonyl) benzene-1,3,5-triol (L2) molecules. The spatial and electronic structure of molecules in various tautomeric forms was determined. It was shown that the stability of these compounds is primarily due to the presence of strong intramolecular hydrogen bonds (IHB), which form six-membered cycles, and the isomerism of the molecule, which assume the formation of IHB. The structures where IHB form five-membered cycles, are less stable. In general, for the L1 and L2 molecules, azo-tautomers were found to be 4 and 3 kJ/mol more stable than the hydrazo-tautomers, respectively. Such a small difference in energy of molecules for the gas phase did not allow us to conclude about the form of existence of molecules in solutions or in the crystalline state. To assess the possibility of transition between tautomers, we used the DFT method to calculate the transition states (TS) between the azo and hydrazo tautomers of the L1 and L2 molecules. The barrier of the transition from the azo form to the hydrazo form was found to be 14 kJ/mol for the molecules L1 and L2, respectively. The interatomic distances, angles, charges on atoms, IR and electronic absorption spectra of tautomeric forms of L1 and L2 molecules were calculated. It has been established that the long-wave absorption band (LB) of the electronic absorption spectrum bathochromically shifts at transition from azo to hydrazo-tautomers by 41 nm for L1 and 40 nm for L2. The introduction of a nitro group also leads to a bathochromic shift of the LB by 22 nm at transition from azo-tautomer L1 to hydrazo-L1 L2 and by 21nm at transition from azo-L2 to hydrazo-L2.
Synthesis, the structure of arylsalicylic amides, which have anthelmintic activity
Authors:   St. Petersburg Chemical and Pharmaceutical Academy, Malakhova Anna Yu. , Kuklin Vladimir N. ,   St. Petersburg Chemical and Pharmaceutical Academy
Published: March 2021

Salicylamides (N-aryl-substituted hydroxybenzamides): well-known organic compounds with diverse biological activity, which were originally investigated as antimicrobial and antifungal substances. Salicylamides have also been used as anthelmintic or molluscicidal agents in human and veterinary medicine. The most famous is 5,2'-dichloro-4'-nitrosalicylamide (niclosamide, yomezan – Germany), resynthesized in the USSR under the name of fenasal, which is effective in treating diphyllobothriasis and hymenolepidosis and has molluscicidal properties. The works of domestic and foreign scientists F.S. Mikhaylitsyn, H. Vanden Bosshe, L.M. Scheibel, P. Andreus, G. Bonse, and others are devoted to the synthesis of salicylamides, their biological activity. I. Arkhipov, R. Gonnert, studied the anthelmintic activity of salicylamides. E. Schraufstatter, H. Mrozik et al. In the works of various authors the “structure-activity linkage” of the synthesized amides is shown. It has been established that the presence of an amide or thioamide bond, substituted amides, is important for anthelmintic activity. The presence of a hydroxyl group in the 2nd position of the aromatic ring of the salicylamide acid fragment is the main condition for the manifestation of activity with respect to tape helminths and trematodes. The best profile of the biological activity of salicylamides was obtained by introducing chlorine into various positions of acid and amine fragments. Acylation of the hydroxyl group in salicylamides leads to a decrease in their toxicity.
Synthesis of imides based on phenylcycloalkanedicarboxylic acids and derivatives trifluoromethylaniline
Authors:   Yaroslavl State Technical University, Koverda Anna A. , Bulanina Valeria D. ,   Yaroslavl State Technical University, Korshunova Alexandra I. ,   Yaroslavl State Technical University, Danilova Angelina S. ,   Yaroslavl State Technical University, Koverda Mikhail N. ,   Yaroslavl State Institute of Raw Materials and Food Quality
Published: March 2021

Previously it was shown that the stereochemical result of the alkylation reaction of benzene with cycloalkanedicarboxylic acids depends on the order of mixing the reagents. Based on this, we have developed methods for the synthesis of phenylcycloalkanedicarboxylic acids and methods for the separation of their isomers. The resulting diastereomerically pure compounds were used to synthesize new imides containing the trifluoromethyl group, which are potentially biologically active substances with antitumor properties. Since aromatic amines containing the CF3 group are weak nucleophiles, during the reaction both complete and incomplete closure of the imide cycle can be observed. The research problem was to study the dependence of the character of the reaction products and their ratio (imide/amides) on the flow conditions: the solvent used and the use of auxiliary reagents. When carrying out the imidization reaction in acetic acid, the formation of a mixture of imide and isomeric amides is observed, and the use of tea in toluene or DMF and in the system of acetic acid – pyridine, taken in a 2 : 3 ratio, leads to the formation of an imide only, but with different yields. Were tested methods for obtaining imides in pyridine through the stage of obtaining dichlorohydrin, which were obtained using thionyl chloride and using triphenylphosphine – carbon tetrachloride. Imides were also obtained in good yields in one-pot reactions by heating a mixture of pyridine, acid, amine, and thionyl chloride. The structure of the new compounds was confirmed by IR spectroscopy, 1H, 13C NMR spectra, capillary electrophoresis, elemental analysis and HPLC.
Synthesis and structure of new derivatives of 2-chloro-N-(3-R-1,5-dinitro-8-oxo-3-azabicyclo[3.3.1]non-6-en-7-yl)acetamides
Authors:   Tula State Lev Tolstoy Pedagogical University, Mukhtorov Loik G. , Ivanova Evgenia V. ,   Tula State Lev Tolstoy Pedagogical University, Nikishina Maria B. ,   Tula State Lev Tolstoy Pedagogical University, Shahkeldyan Irina V. ,   Tula State Lev Tolstoy Pedagogical University, Atroshchenko Yury M. ,   Tula State Lev Tolstoy Pedagogical University, Karimov Makhmadkul B. ,   Dushanbinsky Branch of the National Research Technological University, Kobrakov Konstantin I. ,   Moscow State University of Design and Technology
Published: March 2021

The production of new 3-azabicyclononane derivatives is an important trend in the synthesis of organic compounds. It is known that 3-azabicyclononane is a key pharmacophore of a number of plant alkaloids that are widely used in medicine (aconitin, quinidine, tropane, cocaine, garnet, etc.). Among synthetic heterocycles containing a 3-azabicyclo[3.3.1]nonane fragment, compounds with various types of biological activity were found: analgesic and anti-inflammatory, antimicrobial and fungicidal, anti-cancer, antioxidant, etc. We synthesized a number of new derivatives of 3-azabicyclo[3.3. 1]nonane by Mannich condensation of hydride σ-adduct 2-chloro-N-(2-hydroxy-3,5-dinitrophenyl)acetamide with formaldehyde and primary amines or amino acids. The synthesis was carried out in two stages. In the first stage, under the action of sodium tetrahydride borate on a solution of 2-chloro-N-(2-hydroxy-3,5-dinitrophenyl)acetamide, the C=C bonds of the aromatic ring were reduced to form a 3-charge hydride adduct. The resulting diaduct was isolated from the solution and, while cooling with ice, was introduced into Mannich condensation with formaldehyde and a solution of the primary amine or amino acid. When the reaction mixture was acidified with dilute orthophosphoric acid to pH 4-5, precipitates of the target products precipitated. After recrystallization from ethanol, the yield of the target products, depending on the substituent at the nitrogen atom, was 75-90%. This method is distinguished by relative simplicity, availability of reagents and allows under mild conditions to transfer from the aromatic system activated by nitro groups to 3-azabicyclo[3.3.1]nonane derivatives, containing promising from the point of view of further functionalization nitro, carbonyl, amino groups, and also halogen atom . The structure of the compounds obtained was proved by IR, 1H-, 13C-, two-dimensional correlation NMR spectroscopy, as well as high-resolution mass spectrometry data (HRMS).
Synthesis of polycarbosilane using cobalt chloride(II) catalyst
Authors:   Alexander Grigorievich and Nikolay Grigorievich Stoletovs State University of Vladimir, Chukhlanov Vladimir Yu. , Smirnov Kirill V. ,   Alexander Grigorievich and Nikolay Grigorievich Stoletovs State University of Vladimir, Chukhlanova Natalia V. ,   Alexander Grigorievich and Nikolay Grigorievich Stoletovs State University of Vladimir
Published: March 2021

In this work was studied the synthesis process of polycarbosilane that is a valuable forpolymer in the production of ceramic products, silicon carbide fibers, high-temperature protective coatings for high-speed aircraft, the initial product for the formation of microelectronic mechanical systems. Synthesis was carried out from polydimethylsilane under the influence of high temperatures from 350 to 400 degrees Celsius due to the rearrangement of Kobe. The possibility of polycarbosilane synthesis with a sufficiently high atmospheric pressure in the presence of a cobalt chloride(II) catalyst was shown. The synthesis was carried out in argon. The authors analyzed the obtained compound. The presence of carbosilane bonds in the polymer was identified by the method of infrared Fourier spectroscopy on the Bruker Tensor 27 spectrometer. The received polymer has all the characteristic features of polycarbosilane. This is confirmed, particularly, by the presence in the spectrum of a strong absorption band of about 1035 cm-1, due to fluctuations in the methyl group in the Si-CH2-Si chain. To find the optimal synthesis conditions and obtain the maximum formation of polycarbosilane, the experiment was planned using the Box-Wilson plan. The effect of temperature, reaction time and catalyst content on the formation of polycarbosilane was studied. The optimal conditions for the synthesis are established. The highest formation of associated polycarbosilane was observed at 375 °C at a synthesis duration of 7.5 h. With an increase in temperature to 400 °C and duration of synthesis to 10 hours, a partial decrease in the polymer formation was observed. It is assumed that the intensity of the high temperature and a significant time of the process, begins the pyrolysis of polycarbosilane samples, accompanied by partial loss of mass.
O SUJEITO DE DIREITOS E A BUSCA DOS DIREITOS FUNDAMENTAIS
Authors: Cesar Dias Lopes Gabriel
Published: March 2021

Este artigo tem como objetivo discutir o conceito do sujeito dos direitos, relacionando-o com o conceito de direitos fundamentais. O conceito de direitos fundamentais por sua vez, é controvertido entre os autores, porque há variadas expressões relativas ao tema, gerando certa confusão na sua definição, impedindo, dessa forma, um conceito mais preciso e único do que é um direito fundamental. As conclusões apontam que independente da postura filosófica e ideológica da terminologia, o sujeito de direitos, principalmente no Brasil, vem sendo ameaçado em seus direitos fundamentais adquiridos e garantidos a longo de séculos de lutas para que estes fossem legalmente constituídos.
Premenstrüel Sendrom Semptomlarının Evlilik Uyumu İle İlişkisi
Authors: BAŞAĞAÇ Elif , EGE Emel
Published: March 2021

Amaç: Premenstrüel sendrom kadının, günlük aktivitelerini, iş performansını, aile ve sosyal ilişkileri ile yaşam kalitesini olumsuz etkileyebilir. Bu çalışma, evli kadınlarda premenstrüel sendrom semptomlarının evlilik uyumu ile ilişkisini değerlendirmek amacıyla yapılmıştır.

Yöntem: Tanımlayıcı ve ilişki arayıcı tipte planlanan araştırmanın örneklemini 18-49 yaş grubu evli 138 kadın oluşturmuştur. Verilerin toplanmasında demografik soru formu, Premenstrüel Değerlendirme Formu (PDF), Evlilikte Uyum Ölçeği (EUÖ) kullanılmıştır.

Bulgular: Araştırmada kadınların Evlilik Uyum Ölçeği toplam puan ortalaması 40.33±12.88, Premenstrüel Değerlendirme Formu toplam puan ortalaması 216.18±75.83 olarak tespit edilmiştir. Kadınların Evlilik Uyum Ölçeği puanları ile Premenstrüel Değerlendirme Formu toplam puanları arasında orta düzeyde, negatif yönde ve anlamlı düzeyde bir ilişki olduğu saptanmıştır (p
The Similarity of Abundance Ratio Trends and Nucleosynthetic Patterns in the Milky Way Disk and Bulge
Authors: Griffith Emily , Weinberg David H. , Johnson Jennifer A. , Beaton Rachael , García-Hernández D. A. , Hasselquist Sten , Holtzman Jon , Johnson James W. , Jönsson Henrik , Lane Richard R. , Nataf David M. , Roman-Lopes Alexandre
Published: March 2021

We compare abundance ratio trends in a sample of ∼11,000 Milky Way bulge stars (R
GC < 3 kpc) from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to those of APOGEE stars in the Galactic disk (5 kpc < R
GC < 11 kpc). We divide each sample into low-Ia (high-[Mg/Fe]) and high-Ia (low-[Mg/Fe]) populations, and in each population, we examine the median trends of [X/Mg] versus [Mg/H] for elements X = Fe, O, Na, Al, Si, P, S, K, Ca, V, Cr, Mn, Co, Ni, Cu, and Ce. To remove small systematic trends of APOGEE abundances with stellar

, we resample the disk stars to match the

distributions of the bulge data. After doing so, we find nearly identical median trends for low-Ia disk and bulge stars for all elements. High-Ia trends are similar for most elements, with noticeable (0.05–0.1 dex) differences for Mn, Na, and Co. The close agreement of abundance trends (with typical differences ≲0.03 dex) implies that similar nucleosynthetic processes enriched bulge and disk stars despite the different star formation histories and physical conditions of these regions. For example, we infer that differences in the high-mass slope of the stellar initial mass function between disk and bulge must have been ≲0.30. This agreement, and the generally small scatter about the median sequences, means that one can predict all of a bulge star's APOGEE abundances with good accuracy knowing only its measured [Mg/Fe] and [Mg/H] and the observed trends of disk stars.
Shocks and Molecules in Diffuse Interstellar Cloud Pairs
Authors: Reach William T. , Heiles Carl
Published: March 2021

The diffuse interstellar medium (ISM) is dynamic, and its chemistry and evolution are determined by shock fronts as well as photodissociation. Shocks are implied by the supersonic motions and velocity dispersion, often statistically called “turbulence”. We compare models of magnetohydrodynamic (MHD) shocks, with speeds typical of cloud motions through the ISM (3–25 km s−1) and densities typical of cold neutral gas (∼102 cm−3), to archival observations of the H i 21 cm line for gas kinematics, far-infrared emission for dust mass, and mid-infrared emission for high-resolution morphology, to identify shock fronts in three high-latitude cloud pairs with masses of order 50 M
⊙. The clouds have “heads” with extended “tails,” and high-resolution images show arcs on the leading edges of the “heads” that could be individual shocks. The H i shows higher-velocity gas at the leading edges due to shock-accelerated material. For two cloud pairs, one cloud has an active shock indicated by broad and offset H i, while the other cloud has already been shocked and is predominantly “CO-dark” H2. Two-dimensional MHD simulations for shocks parallel to the magnetic field for pairs of clouds show a remarkable similarity to observed cloud features, including merged “tails” due to aligned flow and magnetic field, which leads to lateral confinement downstream. A parallel alignment between magnetic field and gas flow may lead to formation of small molecular clouds.
Finite System-size Effects in Self-organized Criticality Systems
Authors: Aschwanden Markus J.
Published: March 2021

We explore upper limits for the largest avalanches or catastrophes in nonlinear energy dissipation systems governed by self-organized criticality. We generalize the idealized “straight” power-law size distribution and Pareto distribution functions in order to accommodate incomplete sampling, limited instrumental sensitivity, finite system-size effects, and “Black Swan” and “Dragon King” extreme events. Our findings are as follows. (i) Solar flares show no finite system-size limits up to L ≲ 200 Mm, but solar flare durations reveal an upper flare duration limit of ≲6 hr. (ii) Stellar flares observed with Kepler exhibit inertial ranges of E ≈ 1034–1037 erg, finite system-size ranges of E ≈ 1037–1038 erg, and extreme events at E ≈ (1–5) × 1038 erg. (iii) The maximum flare energies of different spectral type stars (M, K, G, F, A, giants) reveal a positive correlation with the stellar radius, which indicates a finite system-size limit imposed by the stellar surface area. Fitting our finite system-size models to terrestrial data sets (earthquakes, wildfires, city sizes, blackouts, terrorism, words, surnames, web links) yields evidence (in half of the cases) for finite system-size limits and extreme events, which can be modeled with dual power-law size distributions.
State-switching Mechanism of Intermittent Pulsars
Authors: Rusul Abdujappar , Zheng Xiao-Ping , Esamdin Ali , Guo Liang , Xia Li-Xin
Published: March 2021

The emission feature of intermittent pulsars is significant for understanding the pulsar emission mechanism. Using the observational evidence of radio emissions turning on and off and the corresponding spin-down rates in these two states of an intermittent pulsar, we will examine the polar-cap potential drop, gap height, and curvature radii of a few intermittent pulsars within the regime of the pulsar polar-cap emission theory by applying the current loss and energy flux of particle flow to pulsar braking, which are generally associated with radio emission from the polar cap. It is seen that the polar-cap parameters of the intermittent pulsars are almost equal to their maximum values, which is the main prediction of the pulsar polar-cap theory with respect to the breaking of the radio emission. It is also noticed that the intermittent pulsars are distributed near the dipole death line in the

diagram, which is consistent with their emission features and the calculated polar-cap parameters. To further confirm the state switching of the intermittent pulsar, the relationships among spin-down rate, gap height, potential drop, and activity duty cycles of PSR B1931+24 are discussed. It is found that the gap height has an anticorrelation with the activity duty cycle, which indicates that the intermittency of the radio emission has a close connection to the gap height, as indicated by the pulsar polar-cap emission theory.
Detection of Tidal Disruption Events around Direct-collapse Black Holes at High Redshifts with the James Webb Space Telescope
Authors: Regős Enikő , Vinkó József , Stermeczky Zsófia V.
Published: March 2021

This is the third sequel in a series discussing the discovery of various types of extragalactic transients with the James Webb Space Telescope (JWST) in a narrow-field (∼0.1 deg2), moderately deep (m
AB ∼ 27 mag) survey. In this part we focus on the detectability and observational characteristics of direct-collapse black holes (DCBHs) and tidal disruption events (TDEs) around them. We use existing models for DCBH accretion luminosities and spectra, as well as for TDE light curves, and find that accreting DCBH seeds may be bright enough for detection up to z ∼ 7 with JWST NIRCam imaging. TDEs of massive (M ≳ 50 M
⊙) stars around them can enhance the chance for discovering them as transient objects, although the rate of such events is low, a few per survey time. TDEs around nonaccreting black holes of M ∼ 106
M
⊙ may also be detected at z < 7 redshifts in the redder NIRCam bands between 3 and 5 μs. It is also shown that accreting DCBHs appear separate from supernovae on the NIRCam color–color plot, but TDEs from quiescent black holes fall in nearly the same color range as superluminous supernovae, which makes them more difficult to identify.
The Discovery of a Highly Accreting, Radio-loud Quasar at z = 6.82
Authors: Bañados Eduardo , Mazzucchelli Chiara , Momjian Emmanuel , Eilers Anna-Christina , Wang Feige , Schindler Jan-Torge , Connor Thomas , Andika Irham Taufik , Barth Aaron J. , Carilli Chris , Davies Frederick B. , Decarli Roberto , Fan Xiaohui , Farina Emanuele Paolo , Hennawi Joseph F. , Pensabene Antonio , Stern Daniel , Venemans Bram P. , Wenzl Lukas , Yang Jinyi
Published: March 2021

Radio sources at the highest redshifts can provide unique information on the first massive galaxies and black holes, the densest primordial environments, and the epoch of reionization. The number of astronomical objects identified at z > 6 has increased dramatically over the last few years, but previously only three radio-loud (R
2500 = f

ν,5 GHz/f

ν,2500 Å > 10) sources had been reported at z > 6, with the most distant being a quasar at z = 6.18. Here we present the discovery and characterization of PSO J172.3556+18.7734, a radio-loud quasar at z = 6.823. This source has an Mg ii-based black hole mass of ∼3 × 108
M
⊙ and is one of the fastest accreting quasars, consistent with super-Eddington accretion. The ionized region around the quasar is among the largest measured at these redshifts, implying an active phase longer than the average lifetime of the z ≳ 6 quasar population. From archival data, there is evidence that its 1.4 GHz emission has decreased by a factor of two over the last two decades. The quasar’s radio spectrum between 1.4 and 3.0 GHz is steep (α = −1.31). Assuming the measured radio slope and extrapolating to rest-frame 5 GHz, the quasar has a radio-loudness parameter R
2500 ∼ 90. A second steep radio source (α = −0.83) of comparable brightness to the quasar is only 23.″1 away (∼120 kpc at z = 6.82; projection probability <2%), but shows no optical or near-infrared counterpart. Further follow-up is required to establish whether these two sources are physically associated.
Health and economic measures in response to the COVID-19 pandemic- Effect on street vendors
Authors: Romero-Michel Jessica C. , Mokay-Ramírez Karen A , Delgado-Machuca Marina , Delgado-Enciso Josuel , Aurelien-Cabezas Nomely S , Tiburcio-Jimenez Daniel , Meza-Robles Carmen , Delgado-Enciso Osiris G , Guzman Esquivel José , Zaizar-Fregoso Sergio A , Martinez Fierro Margarita L , Rodriguez Sanchez Iram P , Melnikov Valery , Barajas-Saucedo Carlos E , Lara-Esqueda Agustin , Delgado-Enciso Ivan
Published: March 2021

Introduction: COVID-19 pandemic affects human health and the global economy. Its evolution is unpredictable, making it hard for governments to provide response actions suited for all populations. Meanwhile, informal street workers carry on with their labor despite contingency measures to sustain their lives. The objective was to conduct a case-control study to become aware of how street vendors' economy is affected during the COVID-19 pandemic.

Methodology: During phase 2 of the COVID-19 pandemic in a Mexican suburban city. We interviewed informal street vendors (cases) and formal employees (controls).

Results: Before mobility restrictions were in place, population income came 1.5% from formal employment and 23.5% from informal employment (street vendors). Informal employees lived on less than the equivalent of 1.5 Big Macs per day (p <0.001). After the contingency measures, formal employment kept the same, while the informal employment ratio increased to 57.4% (p < 0.001). The street vendors were almost 100-times less likely to be concerned about the coronavirus outbreak (p < 0.001) and were 38-times less likely to stop working compared with the formal workers (p < 0.001).

Conclusions: We have proven that street vendors are a sector of the population that is highly vulnerable to significant economic loss due to contingency measures. Informal workers cannot stop working despite the “Stay at Home” initiative because the government has not implemented strategies that guarantee their survival and their families. Therefore, street vendors continue to be a source of the virus's spread throughout cities.
Clinical and mycological characteristics of keratitis caused by Colletotrichum gloeosporioides: A case report and review of literature
Authors: Izadi Alireza , Soleimani Mohammad , Daie Ghazvini Roshanak , Hashemi Seyed Jamal , Gramishoar Mohssen , Ahmadikia Kazem , Aminizadeh Mehdi , Ghahri Mohammad , Abedinifar Zohre , Barac Aleksandra , Khodavaisy Sadegh
Published: March 2021

Introduction: Colletotrichum species are well-known plant pathogens, which have been increasingly reported as the cause of keratitis or subcutaneous lesions in humans. In this study we reported a rare case of fungal keratitis from Iran and reviewed the literature.

Case Presentation: A 69-year-old man whose right eye was injured by herbal material was examined by slit-lamp biomicroscopy and mycology investigation of corneal scrapings was done. The grown filamentous fungal was identified as Colletotrichum gloeosporioides based on morphological characteristics and DNA sequence of the internal transcribed spacer region. The isolated strain was sensitive to amphotericin B, caspofungin, anidolafungin, micafungin, voriconazole, and relatively resistant to fluconazole, and itraconazole. Patient was successfully treated with voriconazole.

Conclusions: This report highlights that the early and accurate identification and therapy can helpful to management keratitis caused by C. gloeosporioides.
COVID-19 in Sudan
Authors: Ahmed Ayman , Mohamed Nouh Saad , EL-Sadig Sarah Misbah , Fahal Lamis  Ahmed , Abelrahim Ziad Bakri , Ahmed Eiman Siddig , Siddig Emmanuel Edwar
Published: March 2021

The steadily growing COVID-19 pandemic is challenging health systems worldwide including Sudan. In Sudan, the first COVID-19 case was reported on 13th March 2020, and up to 11 November 2020 there were 14,401 confirmed cases of which 9,535 cases recovered and the rest 3,750 cases were under treatment. Additionally, 1,116 deaths were reported, indicating a relatively high case fatality rate of 7.7%. Several preventive and control measures were implemented by the government of Sudan and health partners, including the partial lockdown of the country, promoting social distancing, and suspending mass gathering such as festivals and performing religious practices in groups. However, new cases still emerging every day and this could be attributed to the noncompliance of the individuals to the advocated preventive measurements.