bluuebunny/crossref_metadata_2025 huggingface dataset:
The Study of Creep and Deformation Properties of Sulfur-Containing Arbolit Exposed to Various Compression Stresses
Authors: Sokolova Yulia A. , Akulova Marina A. , Isakulov Baizak R. , Sokolova Alla G. , Kul’sharov Berikbay B. , Isakulov Abikhabir B.
Published: September 2021

The present paper considers the study of creep and deformation properties of sulfur-containing arbolit exposed to various compression stresses. Investigating the creep of lightweight arbolit concretes greatly affecting the performance of bearing and envelope structures draws a special attention during the last years. This issue is of particular relevance in the regions with hot and sharp continental climate. Arbolit concrete is one of the lightest building materials with low thermal conductivity and good soundproof properties. The modern postulates of theory and practice of creation, development of high-strength arbolit concretes on the base of composite sulfur-containing binders have become the methodological framework of the present research. While carrying out scientific research, the following standard measuring and analysis methods of physical and mechanical properties have been used for sulfur-containing arbolit composites. Experimental tests have been implemented on the 28-days samples made of sulfur-containing arbolit, with the cotton plant footstalks as an organic component. The researched samples were vapor sealed with the purpose to eliminate overlapping the processes of contraction and creep. The experimental results have shown that the analysis of prisms deformation in time demonstrates certain derivation from the pattern. Deformation of prisms made of sulfur-containing arbolit loaded at the low stress level were growing at a slower rate that the same deformations at a higher stress level. No derivation has been observed for the prisms of sulfur-containing haydite concrete. For both types of concrete, creep deformation has reached the values exceeding completely recoverable deformation by a factor of 2 or all the samples, the rapid growth of creep deformation has been observed after loading, followed by the gradual slowdown of deformation growth. For sulfur-containing lightweight concretes, as the test shown, the rate of creep deformation growth depends on the hardening curve in time reflecting the process of concrete hardening. This, if compared with sulfur-containing lightweight concretes, creep of sulfur-containing arbolit concrete is significantly lower that eventually leads to the loss of creep deformation at the same stress level. The obtained results can be used when manufacturing an efficient wall material for residential construction, including seismic areas.
Influence of Processing in Radio-Frequency Low Pressure Plasma on the Adhesion of Synthetic Fibers to Polymer Binders
Authors: Karimullin Ilnur , Timoshina Yuliya , Voznesensky Emil , Sisoev Vladislav , Kulevtsov Gennady , Shagivalieva Rimma
Published: September 2021

The paper presents the results of a study of the effect of radio-frequency (RF) plasma modification on the adhesion of ultra-high molecular weight polyethylene (UHMWPE) and polypropylene (PP) fibers to epoxy-diane (ED), epoxy-urethane (EU) and polyester (PES) binder. To assess the adhesive properties, the wet-pull-out method was used, which makes it possible to determine the normalized value of the destructive load of the microcomposite by the force of pulling out the fiber from the polymer matrix.
Composite Material for the Manufacture of Plastic Sleepers
Authors: Kondrashchenko Valerii I. , Wang C. , Matseevich Tatyana A. , Askadskii Andrey A.
Published: September 2021

The composite materials intended for the manufacture of plastic sleepers were produced, which significantly differ from the materials widely used in railway transport of wooden and reinforced concrete sleepers. The coefficients of linear thermal expansion of the obtained materials are significantly lower. Polyvinyl chloride is used as a polymer binder, and the filler is a mixture of softwood flour with the mineral filler in the form of finely ground chalk. It was shown that by varying the content of the components of the composite, a change in its density is achieved by 19%, and the change in the value of the coefficient of linear thermal expansion depends on the temperature and relaxation of internal stresses in the samples, varying by 18.7 times – from 288.4·10-6 to 15.4·10-6 °C -1.
Influence of Nonequilibrium Low-Temperature Plasma on the Properties of Nonwoven Fabric Based on Polypropylene
Authors: Galimzyanova Rezeda Yu. , Lisanevich Maria S. , Khakimullin Yuri N.
Published: September 2021

Investigation of the effect of low-pressure NLTP in nitrogen, argon, propane-butane and air on the properties of a multilayer medical-purpose material based on polypropylene used for the manufacture of sanitary-hygienic and medical products.
It is shown that after plasma treatment of argon, nitrogen, propane-butane, the surface polarity of the CMC material changes significantly, as evidenced by a decrease in the wettability angle and an increase in capillarity. The most significant changes in indicators are observed in the case of plasma treatment in argon and nitrogen. However, in the case of argon, less processing time is required to achieve the effect. Plasma treatment leads to a slight decrease in tensile strength, no more than 10-15%.
It is also shown that when plasma is treated in an argon atmosphere, such characteristics of a nonwoven material as air permeability, hygroscopicity increase, and a decrease in rigidity is observed. The study of the structure of the material (pore size) showed that the treatment with NLTP leads to a significant decrease in the size of large pores and an increase in the size of medium and small pores
Fluoroplastic- and Bio-Based Composites Materials for PEM Fuel Cells Bipolar Plates
Authors: Faddeev Nikita , Tokarev Denis , Molodtsova Tatyana A. , Belichenko Maxim , Klushin Victor
Published: September 2021

Conductive polymer composite materials for polymer electrolyte membrane fuel cells bipolar plates have been successfully prepared from renewable plant biomass sources and copolymers of tetrafluoroethylene with vinylidenefluoride. The composites are based on various conductive fillers (natural, oxidized and colloidal graphite’s) and polymer binder (the 5-HMF synthesis by-product or fluoroplastic). The influences of type and content of binder and type of conductive filler on the mechanical properties and conductivity were investigated. Conductivity of the composites decreases with increasing of polymer content, but its mechanical properties changes inversely. Composite based on 5-HMF by-products (content 30 wt.%) and colloidal graphite as a filler meets the DOE requirements for a mechanical strength. Flexural and compressive strengths were 25 and 32 MPa, respectively. Composites based on fluoroplastic 32 (content 30 wt.%) and fluoroplastic 42 (content 20 wt.%) with colloidal graphite as a filler and fluoroplastic 42 (content 20 wt.%) with nature graphite have flexural strength values close to the target value of DOE and amounted to 24, 17 and 19 MPa, respectively. Interfacial contact resistance depends to a greater extent on the nature of the filler and is maximum for composites based on natural graphite. Composites based on fluoroplastic 42 at any filler content correspond to the requirements DOE ≤ 0.01 ohm∙cm2. Composite based on 5-HMF synthesis by-product (resin) and fluoroplastic with conductive filler (colloidal graphite) shows a great potential application as bipolar plates for PEMFCs.
The Investigation of Effect of Superconstructive Thermoplastics on the Properties of Epoxy Anhydride Binders
Authors: Kapasharov Artur T. , Malkov Georgiy V. , Garifullin Nilson O. , Chernyayev Dmitry A. , Shakhmurzova Kamila T. , Badamshina Elmira R.
Published: September 2021

The present paper is aimed to investigate the effect of modifiers, such as poly (phenylene sulfone) and poly (aril ether ketone), on physico-mechanical and thermophysical properties of heat-resistant epoxy-anhydride binder based on EHD epoxy resin. It was found that the addition of poly (phenylene sulfone) and poly (aril ether ketone) can improve mechanical and impact strength characteristics of the binder with no reduction in heat resistance and thermal stability.
Anionic Copolymerization of Acrylonitrile with Ethyl Acrylate under the Action of the Initiating System of 1,4-Diazabicyclo[2.2.2]Octane – Ethylene Oxide
Authors: Podvalnaya Yulia V. , Tarasov Aleksandr E. , Grishchuk Alexander A. , Chernyayev Dmitry A. , Badamshina Elmira R.
Published: September 2021

It was found, studying acrylonitrile copolymerization with ethyl acrylate in dimethyl sulfoxide under the action of anionic initiating system of 1,4-diazabicyclo [2.2.2] octane – ethylene oxide, that the obtained copolymers have a branched structure. An increase in the molar fraction of ethyl acrylate in the reaction medium leads to a decrease in the initial rate of acrylonitrile polymerization. Thermal behavior of copolymer samples was investigated; it was found that ethyl acrylate, being introduced into the polyacrylonitrile structure, both reduces thermal effects related to the reactions taking place during heat treatment of copolymers, and increases the half-width of the heat release peak.
Development of a Coating Method for Polydecylmethylsiloxane Selective Layer on Polysulfone Hollow Fiber Support
Authors: Borisov Ilya L. , Grushevenko Evgenia , Buinova Elena , Volkov Vladimir
Published: September 2021

The paper presents a comparison of the techniques for polydecylmethylsiloxane selective layer coating to the inner and outer sides of a polysulfone hollow fiber support. It has been shown that coating to the outer side allows one to obtain a composite membrane with a higher selectivity for CO2/N2 vapor. A decrease in the number of defects in the selective layer is achieved by increasing the viscosity of the polydecylmethylsiloxane solution. The resulting membrane was characterized in the separation of a model mixture of hydrocarbons, and a high separation selectivity was shown - 12.4 with respect to the n-butane / methane gas pair.
Study of the Chemical, Climatic and Thermal Resistance of Epoxy Coatings Filled with Natural and Synthetic Wollastonite
Authors: Gotlib Elena M. , Phuong Ha Thi Nha , Yamaleeva Ekaterina , Galimov Engel , Hung Nguyen Duy
Published: September 2021

The article shows that synthetic wollastonite, obtained on the basis of a mixture of calcium oxide and silicon oxide, as well as calcium carbonate and silicon dioxide, increases the thermal stability of epoxy materials filled with it. The chemical and atmospheric resistance of epoxy films filled with wollastonite is on average 0.2 – 0.3% lower than that of the base composition, which is probably due to the porosity of both synthetic and natural wollastonite. The phase composition of synthetic wollastonite does not significantly affect chemical resistance of epoxy materials filled with it. The chemical resistance of epoxy compositions, regardless of their composition, is lower in weakly acidic solutions and water, in comparison with weakly alkaline and saline solutions.
Research of Polyphenylenesulphide Synthesis Depending on Nature and Comonomer Rating
Authors: Takova Diana H. , Lamashvili Ludmila S. , Dubovitskaya Ludmila L.
Published: September 2021

Investigated the synthesis of polyphenylene sulfide in the environment of an aprotic polar solvent based on p-dichlorobenzene and p-dibromobenzene according to the nature comonomer rating. Infrared spectroscopy and thermogravimetric analysis of the obtained samples are presented.
IR-Spectroscopic Studies of Bituminous Sands of the Zhyly-Oi Deposit
Authors: Abdikarimov Malik N. , Turgumbayeva Raushan Kh. , Mukatayeva Zhazira
Published: September 2021

The organic part of bituminous Sands (BS) is a chemical raw material of complex and unstable composition. The physical and chemical properties and composition of this raw material depend on the BS Deposit, the method of separation of the organic part, methods and equipment for analysis. The organic component-natural bitumen-is an oil dispersed system, the dispersed phase of which is formed by high – molecular components-resins and asphaltenes; the dispersed medium is made up of lighter hydrocarbons. It was found that traces of tungsten oxide (V), primary and secondary alcohols, and esters were found in the bituminous rock of the Deposit. It was found that natural bitumen extracted from BS contains saturated hydrocarbons: linear: n-heptane, n-decane and cycloparaffins: 1-phenyldodecane, methylcyclohexane, various primary and secondary alcohols, ketone and esters.
New Mixed-Ligand Metal-Containing Monomer Based on Cobalt Acrylate and 4-Phenyl-2,2':6',2″-Terpyridine Ligand: Synthesis, Characteristics and Thermal Properties
Authors: Sorin Evgeny S. , Baimuratova Rose K. , Chernyayev Dmitry A. , Korchagin Denis V. , Uflyand Igor E. , Dzhardimalieva Gulzhian I.
Published: September 2021

New complex based on cobalt (II) acrylate and 4′-phenyl-2,2′:6′,2″-terpyridine (PhTpy) was synthesized and characterized using a number of analytical techniques including IR and UV- vis spectroscopy, elemental, X-Ray and TGA/DSC analysis. The complex has high thermal stability and crystallinity. It is found that decomposition of the complex is accompanied by thermal polymerization of acrylic fragments that is a potential way for the preparation nanoparticles of metals or their oxides stabilized by the polymer matrix.
Thermogravimetric Аnalysis of Different Bitumens
Authors: Abdikarimov Malik N. , Turgumbayeva Raushan Kh. , Samatov I.B. , Mukatayeva Zhazira
Published: September 2021

Thermogravimetric analyses of the samples were performed on a Q-1000/D derivatograph of the F. Paulik, J. Paulik and L. Erdey system of the MOM company (). The method is based on registering changes in the thermochemical and physical parameters of a substance that can be caused when it is heated by the device. The thermochemical state of the sample is described by the curves: T (temperature), DTA (differential thermoanalytic), TG (thermogravimetric) and DTG (differential thermogravimetric). The last curve is derived from the TG function.
Copolymerization of Glycidyl Methacrylate and 1,1,1,3,3,3-Hexafluoroisopropyl Acrylate
Authors: Grigoreva Alexandra O. , Tarankova Kseniia , Zaitsev Sergey D.
Published: September 2021

The copolymerization of 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) and glycidyl methacrylate via reversible addition-fragmentation chain transfer (RAFT) process was investigated. 2-cyano-2-propyl dodecyl trithiocarbonate (CPDT) was used as chain transfer agent. It is turned out that CPDT and polymeric chain transfer agent obtained based on HFIPA and CPDT provide a good control over molar mass characteristic of copolymers (Đ = 1.05). Reactivity ratios were found to be r1(GMA) = 1.57 and r2(HFIPA) = 0.05 by Fineman–Ross model.
The Influence of Polyvinyl Alcohol Solutions Concentration on the Rheological and Elastic and Strength Properties of Film Materials
Authors: Radaykina Elena A. , Kuzmin Anton M. , Konakov Andrei V. , Kotin Alexandr V.
Published: September 2021

During the study, solutions and film materials have been obtained with a concentration of polyvinyl alcohol in distilled water in the range of 1 ... 15 %. The rheological properties of the resulting solutions have been studied by rotational viscometer HAAKE VT 550 at a temperature of 20° C and 80° C. Film materials have been molded by cast film method. The elastic and strength properties of the film materials samples have been determined with a Gotech 7000M universal testing machine. It has been shown that with an increase in polyvinyl alcohol concentration, there has been a decrease in the elastic and strength properties. Samples of film material with 1% and 5% polyvinyl alcohol content completely dissolve in water in 10 and 20 minutes, respectively.
Investigation of the Properties of Polyetheretherketone Blends and Carbon-Filled Composites Based on them
Authors: Slonov Azamat L. , Musov Ismel V. , Rzhevskaya Elena V. , Musov Khasan V. , Tlupov Aslanbek F. , Zhansitov Azamat A.
Published: September 2021

The study of the properties of PEEK blends with different melt flow rate (MFR) and carbon-filled composites based on them was carried out. It was found that with an increase in the relative difference in the MFR of the blended PEEKs, there is an increase in the deviation of the experimental MFR values from the additive ones. Up to a relative difference in the MFR of the components equal to 60%, the blends obey the additivity rule. It is shown that the achievement of a certain MFR value by blending polymers with different viscosities leads to the production of materials with similar properties. Carbon-filled composites based on PEEK blends also demonstrate very similar rheological, mechanical and thermal properties, which indicates the effectiveness of the method of blending PEEKs with different viscosities to achieve the required rheological properties.
New Express Method of Non-Destructive Controlling of the Porous Structure of Asymmetric Membranes
Authors: Matveev Dmitry N. , Borisov Ilya L. , Vasilevsky Vladimir P.
Published: September 2021

An important practical and fundamental problem in the production of porous polymer membranes is the study of the porous structure and the detection of "defects" or large pores in the area of ​​the membrane. Known porosimetry methods cannot solve this problem. This work proposes a new non-destructive express method for studying the porous structure of asymmetric polymer membranes in high-intensity electric fields. This method can be successfully implemented on both flat sheet and hollow fiber membranes with a known porous structure. On the example of hollow fiber membranes made of polyacrylonitrile and polysulfone an assessment of the chemical structure effect of the membrane material on the high-voltage discharge currents in a highly inhomogeneous electric field through hollow fiber membranes with a given pore size was made. Under normal conditions and an average intensity of an inhomogeneous electric field E = 5 kV/cm, the results obtained allow us to conclude about a certain practical potential of the developed express method.
Analysis of Residual Stresses in a Polymer Cylinder when it is Stopped and then Cooled in a Nonlinear and Linearized Problem Settings
Authors: Lesnyak Liubov I. , Andreev Vladimir I. , Yazyev Serdar B. , Avakov Arthur A. , Doronkina Irina G.
Published: September 2021

In conclusion, one should say that, to determine the approximate stress state in the body, it is quite enough to consider the problem in a linearized problem setting. When determining the deformed state, it is necessary to consider the problem exclusively in a nonlinear setting.
New Chain-Extenders for Recyclable Cross-Linked Polyurethanes
Authors: Ponomareva Polina F. , Platonova Elena O. , Polezhaev Alexander V.
Published: September 2021

A synthetic method for the new chain extenders with different amounts of furan groups and a prepolymer derived from three-furyl diol was developed. A series of polyurethanes cross-linked via the Diels-Alder reaction with various amounts of bismaleimide were produced. The structure, mechanical and thermal properties, and recycling ability of the obtained materials were investigated.
Cryophylactic Solution Based on Pectic Oligosaccharides for the Creation of New Dosage Forms
Authors: Gorshkova Raisa , Slobodova Dara , Pankov Stanislav , Novoselov Nickolay
Published: September 2021

For the first time in a wide temperature range, the rheology of aqueous solutions of oligo-and polysaccharides obtained by the method of combined fractionation from the secondary phytomass of apple pomace and albedo pomelo has been studied. The values of the freezing point have been determined and the possibility of the practical use of oligosaccharides as components of special-purpose preparations in liquid dosage form has been shown. On the basis of oligosaccharides obtained by the method of combined fractionation from the secondary phytomass of apple pomace and albedo pomelo, cryophylactic media have been created for the first time, possessing physicochemical stability in a wide temperature range. The main rheological and temperature characteristics of the obtained compositions have been studied and the possibility of the practical use of oligosaccharides as components of medical preparations for special purposes in liquid dosage form has been shown.
The Use of Polymeric Materials in Modern Dentistry
Authors: Kushkhov Tembulat A. , Makhieva Diana A. , Kardanova Larisa V. , Tkhazaplizheva Marina T. , Khashukoev Adalbi Z.
Published: September 2021

The achievements and discoveries of chemical science have firmly established themselves in all branches of humanity. One of the most significant chemistry possibilities is the polymerization and polycondensation of compounds, which, in turn, are methods for producing polymers. Polymers are high molecular weight compounds consisting of many units (monomers) linked by chemical bonds. Unique polymer compounds are the basis of plastics, chemical fibers, rubber, paints, and varnishes, adhesives [8]. Polymers are used for the manufacture of removable prostheses, materials for fillings and inlays, orthodontic appliances, artificial teeth, dental implants, as well as in the creation of artificial heart valves, artificial kidney devices, artificial circulation, artificial heart [6].
Thermal Behavior of the Porous Polymer Composites Based on LDPE and Natural Fillers Studied by Real Time Thermal Microscopy
Authors: Grigorieva Elena A. , Olkhov Anatoly A. , Gradov Oleg V. , Gradova Margaret A.
Published: September 2021

Foaming of the biodegradable polymer composites and melting of the gas-filled materials were studied using thermal microscopy. Composite materials under investigation were based on the low density polyethylene and natural products used as the polymer composite fillers: wood flour and corn starch. Porous structure of the composite material was obtained using a chemical porogen “Hydrocerol BIF”. It has been shown that the foaming and melting processes occur differently in the polymer composite samples containing either different amount of the fillers or the same content of the filler with different particle size fractions. Thermal behavior of the composite samples was shown to be different from the behavior of pure polyethylene, which indicates non-additivity (superadditivity) of the contribution of the above components to the thermal behavior of the final composite material. All the results obtained using heating stage (hot stage) microscopy were in good agreement with the SEM and DSC data.
The Results of the Compromise Task Solution Directed for Development of Polymer-Modified Binder
Authors: Polonik V.D. , Kukleva A.S. , Avdeev N.D. , Shlyaptseva M.D. , Nikol'skii Vadim G. , Gordeeva I.V. , Kotova S.V.
Published: September 2021

This work presents the results of optimization compositions of polymer-modified binder (PMB) by a compromise task. The conducted study of influence two prescription factors – containing styrene-butadiene-styrene and sulfur – on which is a set of indicators of polymer-bitumen binders were carried out. The regularities of these factors of mutual influence were established by such indicators as the Fraas brittleness temperature, penetration, softening point, ductility. The dosages of SBS and sulfur have been determined by ensuring the achievement of the required level of PBB indicators in accordance with GOST R 52056-2003 «Bitumen-polymer road binders are based on styrene-butadiene-styrene block copolymers. Specifications».
Modified Epoxy Resins for Perpreg Technology
Authors: Kostromina Nataly V. , Olikhova Yu.V. , Malakhovskii S.S. , Gorbunova I.Yu.
Published: September 2021

A curing system has been developed for obtaining high-strength compositions matrix, which is used in the production of composites based on reinforced carbon fiber using prepreg technology with a curing temperature of . A technology has been developed for combining an epoxy oligomer with a curing agent and modifier. The pot life of the prepared prepregs is at least 15 days.
Influence of Phytonorman Eco-Oils Nature and Content on Processing of the Elastomeric Materials Based on Nitrile Butadiene Rubber Analysis
Authors: Naumova Yulia A. , Lyusova L.R. , Kotova S.V. , Volkov A.O.
Published: September 2021

The work presents the results of testing new eco-oils in elastomeric materials based on nitrile butadiene rubber (NBR). The influence of eco-oils grade and content on the rubber mixes based on NBR 2665 processing was studied. It is established that Phytonorman 212 acts as a technologically active additive that improves the rheological and relaxation characteristics of rubber mixes. Phytonorman 213 acts as an activator of the vulcanization process when eco-oils content is 2 phr. To maintain the complex of physical, mechanical and working performances, so as to prevent the slowdown of the vulcanization process at 7 phr eco-oil content it is recommended to adjust vulcanizing group component content and filler grade.
Measurement and dosimetry of airborne long-lived alpha-emitting radionuclides
Authors: Bigu J
Published: September 2021

Sampling principles, monitoring instrumentation and characterization of long-lived radioactive dust (LLRD) generated in U-Th mine and mill operations are discussed. Methods and techniques for the quantification, radionuclide identification and the study of other
important characteristics of LLRD (e.g., electrical charge) are reviewed. Furthermore, field and laboratory measurements and methods of radiation dose assessment are revised. Some emphasis is placed in this work on occupational worker exposure assessment and the principles, methods and techniques of
'external' radiation exposure, internal dosimetry, and dosimetric models, followed by a brief discussion of relevant methods of bioassay, thoron-in-breath monitoring and Whole Body Counting. It is clear that in spite of constant advances in the several areas which are the subject of this paper,
there is still considerable room for improvement. For example, there is no universally accepted sampling protocol and sampler for routine LLRD monitoring for occupational hygiene exposure calculation purposes. Other areas for improvement could include calibration of instruments and improved
sensitivity in radionuclide quantification and identification, to name but a few examples.
Hepaticogastrostomy versus choledochoduodenostomy
Authors: Tyberg Amy , Napoleon Bertrand , Robles-Medranda Carlos , Shah Janak N. , Bories Erwan , Kumta Nikhil A. , Yague Andres Sanchez , Vazquez-Sequeiros Enrique , Lakhtakia Sundeep , Chafic Abdul Hamid El , Shah Shawn L. , Sameera Sohini , Tawadros Augustine , Ardengh Jose Celso , Kedia Prashant , Gaidhane Monica , Giovannini Marc , Kahaleh Michel
Published: September 2021

Background and Objectives:

EUS-guided biliary drainage (EUS-BD) offers minimally invasive decompression when conventional endoscopic retrograde cholangiopancreatography fails. Stents can be placed from the intrahepatic ducts into the stomach (hepaticogastrostomy [HG]) or from the extrahepatic bile duct into the small intestine (choledochoduodenostomy [CCD]). Long-term patency of these stents is unknown. In this study, we aim to compare long-term patency of CCD versus HG.

Methods:

Consecutive patients from 12 centers were included in a registry over 14 years. Demographics, procedure info, adverse events, and follow-up data were collected. Student's t-test, Chi–square, and logistic regression analyses were conducted. Only patients with at least 6-month follow-up or who died within 6-month postprocedure were included.

Results:

One-hundred and eighty-two patients were included (93% male; mean age: 70; HG n = 95, CCD n = 87). No significant difference in indication, diagnosis, dissection instrument, or stent type was seen between the two groups. Technical success was 92% in both groups. Clinical success was achieved in 75/87 (86%) in the HG group and 80/80 (100%) in the CCD group. A trend toward higher adverse events was seen in the CCD group. A total of 25 patients out of 87 needed stent revision in the HG group (success rate 71%), while eight out of 80 were revised in the CCD group (success rate 90%). Chi square shows CCD success higher than HG (90% vs. 71%, P = 0.010). After adjusting for diagnosis, jaundice or cholangitis presentation, instrument used for dissection, and gender, CCD was 4.5 times more likely than HG to achieve longer stent patency or manage obstruction (odds ratio 4.5; 95% 1.1548–17.6500, P = 0.0302).

Conclusion:

CCD is associated with superior long-term patency than HG but with a trend toward higher adverse events. This is particularly important in patients with increased survival. Additional studies are required before recommending a change in practice.
Clinical and Biochemical Characteristics of Patients with Renal Tubular Acidosis in Southern Part of West Bengal, India
Authors: Chakraborty Partha Pratim , Bhattacharjee Rana , Patra Shinjan , Roy Ajitesh , Gantait Kripasindhu , Chowdhury Subhankar
Published: September 2021

Purpose of the Study:

Reversible proximal tubular dysfunction associated with distal renal tubular acidosis (dRTA) mimics type 3 RTA, a condition classically associated with features of both proximal RTA (pRTA) and dRTA. Proximal tubulopathy has been reported in children with primary dRTA, but the data in adults are lacking.

Study Design:

In this hospital record-based retrospective study, data from 66 consecutive cases of RTA, between January 2016 to December 2018, were retrieved and analyzed.

Results:

Mean age of the study population was 25.3 years (range: 3 months to 73 years). Six (9.1%) of them had pRTA, 58 (87.9%) had dRTA, 1 (1.5%) had type 3 RTA, and the remaining 1 (1.5%) had type 4 RTA. Ten patients (17.2%) with dRTA and 3 patients of pRTA (50%) had underlying secondary etiologies. Data on proximal tubular dysfunction were available for 30 patients with dRTA, of whom 1 had isolated dRTA, and the rest 29 patients had accompanying completely reversible proximal tubular dysfunction. Among the 10 cases of secondary dRTA, 6 were not evaluated for proximal tubular dysfunction. Of the remaining 4, 3 had reversible form of proximal tubular abnormality. Fifty-two patients with dRTA came from a population, indigenous to the “Rarh” region of India.

Conclusions:

Proximal tubular dysfunction often accompanies dRTA; 75% of the children with primary dRTA, at least 29% of adults with primary dRTA, and at least 30% of adults with secondary dRTA manifest such completely reversible form of proximal tubulopathy. “Rarh’ region of India probably is a hotspot for endemic dRTA.
Detections of Rainbow Trout Antibodies to Infectious Pancreatic Necrosis Virus and Viral Hemorrhagic Septicemia Virus via a Recombinant Protein-Based Enzyme-Linked Immunosorbent Assay
Authors: TAMER Cuneyt , GUMUSOVA Semra , ALBAYRAK Harun
Published: September 2021

Infectious Pancreatic Necrosis Virus (IPNV) and Viral hemorrhagic septicemia virus (VHSV) cause significant losses in the aquaculture industry. There have been few reports of the use of screening rainbow trout for antibodies against IPNV and VHSV as an epidemiological tool. Several ELISAs using a whole virus or recombinant IPNV and VHSV proteins have been described. In this study, a recombinant protein-based enzyme-linked immunosorbent assay (ELISA) for the detection of IPNV and VHSV antibodies in rainbow trout (Oncorhynchus mykiss) was evaluated. To develop recombinant protein-based enzyme-linked immunosorbent assays, a fragment containing the entire length of the gG gene of VHSV and VP2 of IPNV was amplified by PCR using the viruses' genomic RNA and cloned in pET-28a(+) plasmid. Recombinant structural viral proteins (rVP2 and rgG) were expressed in the Escherichia coli BL21 (DE3). The rgG was extracted and purified. 96-well plates were coated with VP2 and gG separately. For VHSV, Assay could detect until 1/15625 dilution in VHSV positive fish serum. For IPNV, Assays could detect until 1/3125 dilution in IPNV positive fish serum. These results show rgG and rVP2, used in ELISA, are more sensitive than virus neutralization tests.
العقل بين ابن المقفع والجاحظ دراسة وموازنة في ضوء المنهج الموضوعاتي
Authors: د. زياد بن علي بن حامد الحارثي د. زياد بن علي بن حامد الحارثي
Published: September 2021

. سعى البحث إلى هدف رئيس هو الكشف عن سمات العقل عند كل من ابن المقفع والجاحظ من خلال كتاباتهما، واتخذ من المنهج الموضوعاتي ومبادئه الأساسية (الأنا والعلاقة مع العالم، والخيال)، وكذا المنهج المقارن أداة علمية للدراسة والموازنة. وشمل البحث عدة محاورمنها: علاقة الأدب بالفلسفة، والعقل في الفكر الإنساني، وتجليات العقل عند كل من الجاحظ وابن المقفع، واختتم البحث بمبحث يوازن بين سمات العقل عند كل منهما. ومن أبرز النتائج التي توصل إليها البحث سمات مشتركة بين ابن المقفع والجاحظ وسمات انفرد بها الجاحظ، ويمكن القول إن وجود خاتمة البحث جاءت لتؤكد أن (العقل) موضوعٌ جليٌّ بل لاستشراف سماته ومظاهره وقيمته الفكرية والعملية المؤثرة في أدب ابن المقفع الأديب الحكيم، والجاحظ الفيلسوف الأديب، وهنا يجتمعان ويفترقان أيضا.
تطبيق القــواعــد الفقهيــة والقانونية على الإجراءات الاحترازية للوقاية من تفشي وباء كورونا المستجد (كوفيد-19)
Authors: محمد بن مرعي الحارثي محمد بن مرعي الحارثي
Published: September 2021

. تتجلى عظمة الفقه الإسلامي في مواكبته للأحداث والنوازل مهما عظمت، والقواعد الفقهية إحدى ركائزه التي تشكِّل إحدى مواده الخصبة في استيعابها تلك النوازل والأحداث، وهذا البحث يبين ذلك بجلاء من خلال تفعيل القاعدتين الكليتين الكبريين: "لا ضرار ولا ضرار" و"المشقة تجلب التيسير" بفروعهما في تأييد الإجراءات الاحترازية التي اتخذتها الدول وفي مقدمتها المملكة العربية السعودية للوقاية من تفشي وباء كورونا الذي أعلنته منظمة الصحة العالمية جائحة عالمية. فقد استوعبت قاعدة: "لا ضرر ولا ضرار" بفروعها ذات الصلة الإجراءات الاحترازية الصارمة التي اتخذت لمنع تفشي وباء كورونا والحد من أضراره، بما في ذلك إيقاع العقوبات على المخالفين درءًا للمفاسد الكبيرة والعامة، في حين شملت قاعدة: "المشقة تجلب التيسير" بفروعها ذات الصلة تأييد الإجراءات الاحترازية المتعلقة بتعليق بعض العبادات والواجبات الشرعية، كالتعليق المؤقت للصلاة في المساجد جمعة وجماعة؛ وذلك بتيسير الشريعة السمحة في ذلك ورفع الحرج عن الأمة، كما انطبقت تلك القواعد على ما صاحب الإجراءات الاحترازية الحازمة من تدابير تخفف من آثار تطبيقها بالقدر الذي يراعي الضرورات الإنسانية والمعيشية، وجاءت القيود الواردة على تلك القاعدتين لتشمل جميع الاحتياطات الشرعية التي اتخذت للموازنة بين المصالح والمفاسد، وكذلك تراجع الرخص الشرعية التي اضطر إلى الأخذ بها بسبب الجائحة، ليبقى الحكم على أصله قبل الجائحة تزامنا مع تناقص الخطورة والعودة التدريجية إلى الحياة الطبيعية بحسب ما يقرره أهل الخبرة من الجهات المختصة. وقد جاءت الإجراءات الاحترازية متوافقة مع النظام الأساسي للحكم ونظرية الظروف الاستثنائية عند القانونيين باعتبارها إحدى النظريات المتفرعة عن مبدأ المشروعية. وقد أوصت الدراسة بالمزيد من العناية الفقهية بهذه النازلة وما قد يماثلها من نوازل الأوبئة -نسأل الله? العافية والسلامة- كتأسيس مركز بحثي فقهي طبي يضم باحثين وخبراء من الفقهاء والأطباء والقانونيين لدراسة النوازل والمستجدات الطبية، وإنشاء كرسي علمي لدراسة الآثار الفقهية والقانونية المترتبة على وباء كورونا المستجد، وتناول موضوع وباء كورونا المستجد بمزيد من الدراسات الفقهية التي تشمل تفاصيل الأحكام الشرعية لهذا الوباء ولآثاره، وعقد مؤتمر علمي عام يتناول نازلة وباء كورونا المستجد وآثارها من جميع الجوانب الفقهية والطبية والقانونية والاقتصادية مع دراسة الفتاوى والقرارات الفقهية التي صدرت بشأنها في ضوء ما يستجد في هذه النازلة. ويتقدم الباحثون بخالص الشكر لعمادة البحث العلمي بجامعة جازان على دعمها لهذا البحث من خلال المشروع البحثي رقم (cov19-13).
خطبة الخلافة عند أبي بكر وعمر -رضي الله عنهما- دراسة بلاغية موازنة
Authors: د. نورة سلمان الجهني د. نورة سلمان الجهني
Published: September 2021

. تناول هذا البحث خطبة الخلافة عند أبي بكر وعمر – رضي الله عنهما – دراسة بلاغية موازنة؛ إذ يهتم بالدراسة البلاغية لنصّ الخطبتين، والموازنة بينهما من حيث أوجه الاتفاق والاختلاف، فبدأ البحث بتوطئةٍ تناولت الجانب التاريخي للخطبتين، ثم الدراسة الموازنة بينهما من جانبين، أولهما: من حيث الاستهلال، وثانيهما: من حيث المبادئ والقيم المراد تثبيتها في كلتا الخطبتين، مع ربط الفن البلاغي بغرض القائل، وكيف ساعدت الألفاظ والأساليب على تحقيق هذا الغرض. ثم كيف تآزرت هذه المبادئ والقيم بعضها مع بعض في تحقيق الغرض الرئيس للقائل، وخلص البحث إلى بيان أهم أوجه الاتفاق والاختلاف بين الخطبتين.
تاريخ التواصل الاجتماعي خلال الجوائح التاريخية - مقارنة بين جائحة الإنفلونزا الإسبانية وجائحة كورونا 2019- دراسة بينيّة
Authors: د. حسن بن عبد الله الأسمري د. حسن بن عبد الله الأسمري
Published: September 2021

. هدفت هذه الدراسة إلى بيان طبيعة التواصل الاجتماعي أثناء الجوائح الكبري، ولتحقيق هذا الهدف، اعتمدت هذه الدراسة على المنهج الوصفي وذلك لتوصيف الإطار العام للظاهرة المتعلقة بالجوائح الكبرى عامة، وبجائحتي الإنفلونزا 1920 ، وكوفيد 19 على وجه الخصوص ، كما تم استخدام المنهج المقارن ، وذلك لتوضيح الفروق العملية بين الجائحتين؛ خاصة فيما يتعلّق بالتواصل الاجتماعي. وقد توصلت هذه الدراسة إلى عدة نتائج أهمها أن الجوائح ظاهرة إنسانية تتكرر في حياة البشر، وللأسف فإن سبب حدوثها الرئيسي مرتبط بسلوك الإنسان؛ خاصة فيما يتعلّق بعاداته الشخصية المرتبطة بالطعام وبالصحة العامة، وأمام المخاطر والخسائر الاقتصادية والآثار الاجتماعية التي تسببها هذه الجوائح، فإن دور وسائل التواصل الاجتماعي والفضائيات يغدو أكثر مركزية وأهمية في مواجهة هذه الآثار، خاصة مع إمكانية مباشرة العمل والتجارة من المنزل.
مداواة البكتيريا المقاومة للمضادات الحيوية (Clostridium difficile) بزراعة الفضلات البشرية (FMT)، دراسة طبية فقهية.
Authors: أمل بنت محمد بن فالح الصغيّر أمل بنت محمد بن فالح الصغيّر
Published: September 2021

. فهذا ملخص لبحث: (مداواة البكتيريا المقاومة للمضادات الحيوية بزراعة فضلات الأمعاء البشرية، دراسة طبية فقهية) والذي من أهم أسباب اختياره: وجود هذا النوع من البكتيريا في المستشفيات والتي تسبب مرض الإسهال المزمن للمرضى المنومين مما قد يؤدي إلى الوفاة و الحاجة لمعرفة الحكم الشرعي في مداواتها بزراعة الفضلات البشرية، فظهرت فكرة البحث من الناحية الطبية والفقهية، ويهدف إلى: معرفة طرق المداواة بهذه الطريقة وتكييفها الفقهي. وقد قُسم البحث إلى تمهيد، ومبحثين، وخاتمة، فالتمهيد في حقيقة البكتيريا وطريقة حدوثها، وجاء في مطلبين،ثم المبحث الأول: التشخيص للمرض وطرق العلاج، وجاء في ثلاثة مطالب، والمبحث الثاني: التكييف الفقهي لمداواة البكتيريا المقاومة للمضادات بزراعة الفضلات البشرية، وجاء في مطلبين. ثم الخاتمة وفيها النتائج، ومنها: 1- أن لمداواة البكتيريا (Clostridium difficile) طريقتان: إما نوع من المضادات، أو زراعة الفضلات البشرية. 2- لطريقة الزراعة أقسام ويختلف الحكم الشرعي باختلافها. 3- الأصل في مشروعية التداوي الإباحة. 4- الأصل في التداوي بالنجاسات التحريم. 5- أن مداواة البكتيريا بزراعة الفضلات إن كانت عن طريق محلول الأنف أو كبسولات الفم فهي محرمة لوجود البديل الأخف منها ضررا. 6- أن مداواة البكتيريا بزراعة الفضلات عن طريق الحقن الشرجية أو منظار القولون فهي مباحة بضوابط إباحة التداوي بالمحرم من تحقق الضرورة، وثبوت فعالية الزراعة وعدم فعالية المضادات، وأن تكون بقدر انتفاء الضرر. 7- ينبغي عدم اللجوء للمداواة بزراعة الفضلات إلا بعد ثبوت عدم فاعلية الأدوية المباحة. وأما التوصيات: فأوصت الباحثات بضرورة دراسة هذه النازلة طبيًا وفقهيًا على نطاق أكبر، ومحاولة إيجاد البديل المباح في العلاج من قبل المختصين قبل البدء بالعلاج بهذه الطريقة، ومعرفة الضرورة عند الأطباء وتقديرها بقدرها.
ظاهرة ضعف ملكة التفسير في العصر الحديث ووسائل علاجها
Authors: د. صالح بن أحمد بن عبيد العلوي د. صالح بن أحمد بن عبيد العلوي
Published: September 2021

. تناول هذا البحث ظاهرة ضعف ملكة التفسير في العصر الحديث وأسبابها ووسائل علاجها. وقد تضمّن معنى التفسير، ونشأة علم التفسير، ومدارسه، وأقسامه، ومراحله منذ مرحلة البروز، وحتى مرحلة الضعف والكمون. ثم بيّن البحث ضرورة إحياء علم التفسير في العصر الحديث، وبعثه، وأسباب الحاجة إليه، وأنّ كل عصر لابد له من مفسّرين يفهمون آليّات تطوّر ذلك العصر ويفسّرون القرآن تفسيرًا ميسّرًا يتواكب مع ذلك التطوّر. ثم أورد البحث مظاهر ضعف ملكة التفسير في العصر الحديث، من ندرة المؤلفات في التفسير وضعف المحتوى العلمي للمصنفات فيه، والاعتماد الواضح في النقل الحرفي لبعض من كتبوا في التفسير في العصر الحديث. وقد عرّج البحث بعد ذلك على ذكر أسباب ذلك الضعف في ملكة التفسير في العصر الحديث سواء على مستوى الأفراد أو المجتمعات، وقد بلغ عدد الأسباب المذكورة 35 سببًا. ثم اختتم البحث ببيان وسائل علاج ظاهرة ضعف ملكة التفسير في العصر الحديث، ومسؤولية كل من الفرد والأسرة والمجتمع في علاج هذه الظاهرة، وقد بلغت تلك الوسائل 42 وسيلة. تناول هذا البحث دراسة ظاهرة ضعف ملكة التفسير في العصر الحديث؛ أسبابها ووسائل علاجها، وقد اقتضى ذلك أن تتناول الدراسة بين يدي الموضوع بيان معنى التفسير في اللغة والاصطلاح، ونشأة علم التفسير، ومرحلة البروز، ثم مرحلة الضعف والكمون، ثم انتهيت ببيان مظاهر ضعف ملكة التفسير في العصر الحديث، وأسباب ذلك الضعف ووسائل علاجها. ولقد تطرّقت الدراسة في نشأة علم التفسير إلى مدارس التفسير في أمصار المسلمين؛ وأشهرها مدرسة التفسير بمكة، ومدرسة التفسير بالمدينة، ومدرسة التفسير بالعراق. كما تناولت الدراسة في مرحلة البروز أقسام المصنّفات في التفسير، وشملت: التفسير المأثور، والتفسير بالرأي. ثم أظهرت الدراسة أسباب انصراف المعاصرين عن الخوض في تفسير القرآن؛ ومنها توسّع متقدمي المفسرين في التصنيف في التفسير إلى حد كبير، جعل من جاء بعدهم يزهد في الكتابة في هذا العلم ظنًّا منه أنه علم اكتمل بحيث لا مجال للزيادة عليه، وكذلك اشتراط العلماء إلمام المفسّر بجملة من العلوم تضعف همم المعاصرين عن تحصيلها مجتمعة، ممّا أدّى إلى ضعف ملكة التفسير عندهم وغياب الموهبة. لذلك تناولت الدراسة تطور العقل البشري مع التطور المادي، وبيّنت بُعد الناس عن فهم القرآن مع تباعد الزمان، وذلك يحتاج إلى وجود علماء يفهمون آليّات هذا التطوّر، ويفسّرون القرآن لإيصاله إلى هذه العقلية الإنسانيّة الحديثة على قدر أفهامهم وثقافاتهم، ثم بيّنت الدراسة مظاهر ضعف ملكة التفسير في العصر الحديث، ومن أهمها: ندرة المؤلفات في التفسير وضعف المحتوى العلمي للمصنفات في التفسير في العصر الحديث، وكذلك الاعتماد الواضح في النقل الحرفي لبعض من كتبوا في التفسير في العصر الحديث. ثم اختتمت الدراسة بسرد أسباب ضعف ملكة التفسير في العصر الحديث وبيان وسائل علاج ذلك.
Environmental Economies, Survival Ecologies, and Economic Interests in Pastoral Uganda
Authors: Kabiito Bendicto
Published: September 2021

This paper presents a departure from the historical cataloguing of scarcity and poverty, as definitive frames of Karamoja sub-region of Uganda; a narrative that purports to portray the duo as natural, permanent and insurmountable features of the sub-region. This study demonstrates that these were both created in and projected onto the sub-region. The study provides evidence to the fact that; 1. Externally-driven pre-colonial, colonial and post-colonial undertakings (which are underrated in many analyses on Karamoja) are the building blocks of the protracted conflicts, insecurities and ecological damages that ravaged Karamoja; 2. The sub-region offers more potentials than limitations as studies on Karamoja tend to portray. This research report is an invitation to both inward and outward looking (of Karamoja) for diagnosis and solutions. Inspired by critical realism and environmental justice theories, the study interrogates policies, mentalities, actions and inactions that fostered economic and ecological exploitation of Karamoja; endangering environmental and social ecologies of the sub-region.  Attention is paid to how these jeopardised the environment-based economy of the sub-region’s population, while highlighting the human, ecological and economic potentials that need and deserve collective action for social and environmental re-address.
Challenges and Growth Trajectory of the Hospitality Industry in South Africa (1994-2020)
Authors: Olowoyo Mary , Ramaila Sam , Mavuru Lydia
Published: September 2021

This article provides a reflection on the challenges and growth trajectory of the hospitality industry in South Africa during the period 1994 – 2020. The overview specifically focused on the challenges and growth in the hospitality sectors such as tourism, food and beverage and hotel industries. The review also captured general trends and perennial challenges that plagued the hospitality industry as a key sector in South Africa during the period under review. Analysis of documented evidence revealed that research studies published during the period under review on the performance of the hospitality industry in South Africa put considerable emphasis on skills and job satisfaction within the industry. Low wages, skilled personnel and working hours still pose a serious threat within the industry. Furthermore, governmental efforts which were essentially aimed at the fundamental transformation of the hospitality industry in South Africa appear to be yielding desired results.
Tourism and Hospitality Research in the Peripheries: Thematic Focus and a Research Agenda from Ghana
Authors: Adu-Ampong Emmanuel , Mensah Christopher
Published: September 2021

Increasing debates on decolonising tourism and hospitality knowledge production have emerged in the context of a largely Western-dominated canon of the research production and dissemination system. This paper contributes to these debates by highlighting and centring the research in and on Ghana. This is accomplished by reviewing and synthesising 238 tourism and hospitality articles authored by 520 authors over 31 years through content analysis. The sample shows a trend toward increased use of quantitative methodology, multiple authorship and underrepresentation of hospitality research. By outlining current thematic convergence, divergence and omissions, we set out a future research agenda. Our findings demonstrate that while research productivity has been increasing consistently , there is a very limited representation of Ghanaian (African) tourism and hospitality research scholarship in the top-tier tourism and hospitality journals. This raises concerns about the need and challenge of increasing the representation and visibility of tourism and hospitality research from the peripheries.
NHỮNG YẾU TỐ ẢNH HƯỞNG ĐẾN Ý ĐỊNH SỬ DỤNG VÍ ĐIỆN TỬ MOMO KHI MUA SẮM TRỰC TUYẾN CỦA SINH VIÊN ĐẠI HỌC CÔNG NGHIỆP TPHCM
Authors: VĂN SƠN NGUYỄN , THỊ TRÚC NGÂN NGUYỄN , THÀNH LONG NGUYỄN
Published: September 2021

Nghiên cứu này tập trung nghiên cứu về các yếu tố ảnh hưởng đến ý định sử dụng ví điện tử Momo khi mua sắm trực tuyến của sinh viên đại học Công nghiệp TPHCM. Kế thừa từ các mô hình nghiên cứu trước đó, nhóm tác giả đã đề xuất mô hình nghiên cứu ảnh hưởng đến ý định sử dụng ví điện tử Momo bao gồm: nhận thức hữu ích, nhận thức dễ sử dụng, nhận thức riêng tư/ bảo mật, ảnh hưởng xã hội và niềm tin vào ví điện tử Momo. Sử dụng thang đo Likert, và phương pháp hồi quy, kết quả cho thấy chỉ ba yếu tố nhận thức hữu ích, ảnh hưởng từ xã hội và niềm tin vào ví điện tử Momo có tác động đến biến phụ thuộc. Từ đó, nhóm tác giả đề xuất một số hàm ý quản trị giúp các doanh nghiệp có những chính sách nhằm nâng cao ý định sử dụng ví Momo của sinh viên.
2x2 Grid Array Design with E-shaped Microstrip Elements
Authors: Baruah Juhi K. , Goswami Sivaranjan , Sarma Kandarpa Kumar , Mastorakis Nikos E.
Published: September 2021

The paper proposes a work of four element in a 2×2 grid fashioned with E-shaped microstrip patch antenna with corporate fed .The paper compares the proposed design with four elements with a single element and a 2 element array design.All the three antenna designs use E shaped microstrip patch as an element. The design of the grid is achieved through the design of a single element, the design of a 1×2 array and finally the design of the 2×2 grid on an FR4 epoxy substrate of thickness 1.5 mm. A corporate feed network of microstrip lines is used to excite the array. The performance of each stage is studied in terms of the return loss parameter, the far field gain, and the beam-widths are observed in each case from simulation results. The resonant frequency in each case is 3.8 GHz. Through comparision of simulation results the paper shows that as the number of elements is increased, the beam-width reduces. In other words, the directivity is increased. Further, it is also observed that the gain and bandwidth is the minimum for the single patch, followed by that of the 1×2 array and the maximum for the 2×2 grid. Thus,it is ssen that the proposed four element antenna with corporate feeding performs better as compared to antennas with either only single patch element or two element array. The construction of the grid leads to increase in gain, bandwidth and directivity of the antenna.