bluuebunny/crossref_metadata_2025 huggingface dataset:
Mathematical Modeling of Optimization Process for Shell Mold Material Physical Properties and Structure
Authors: Odinokov V.I. , Dmitriev E.A. , Evstigneev A.I. , Ivankova Ye.P. , Usanov G.I.
Published: February 2022

A mathematical approach to studying the process of establishing the effect of degree of significance of multilayer shell mold material physical properties and macrostructure on the mold stress-strain state is proposed. It is not possible to solve this problem analytically; therefore, a numerical approach was applied, namely, a proven numerical method and a set of author-developed programs. Knowledge of how the basic physical properties of the shell mold materials and shell mold macrostructure affect the shell resistance to cracking allows, even at the design stage of the pilot shell mold structures, virtual modeling of the thermal and deformation processes occurring therein, i.e. prediction the operability of the designed shell mold. Based on the results of modeling the processes of predicting possible shell mold destruction conditions, the most important parameters and factors of crack formation are established and approach to study of new shell mold fabrication processes is defined.
Improving the Corrosion Resistance of Polished Stainless Steel Parts by Introducing the Energy of the Ultrasonic Field into the Forming Zone
Authors: Mezin Nikolay , Shtubov Nikita , Kiselev Evgeni
Published: February 2022

This article presents the results of experimental studies of the effect of processing conditions on the corrosion resistance of polished parts made of stainless chromium-nickel steel of austenite class 12X18N10T. It is established that the introduction of the ultrasonic field energy into the shaping zone during grinding can increase the corrosion resistance of parts by 12-15 %, depending on the elements of the grinding mode. The latter is explained by a significantly lower heat-force stress during processing, which, in turn, leads to a decrease in the magnitude and depth of distribution of technological residual tensile stresses along the surface layer.
Testing of Magnetoactive Elastomeric Composite Materials
Authors: Minaev Andrey Ja. , Valiev Hammat H. , Korovkin Jury V. , Stepanov Gennady
Published: February 2022

Dynamic tests of new magnetoactive elastomers were carried out in various amplitude-frequency modes on vibrodynamic stands. These materials regular changes in resonance properties under the external constant magnetic fields and loads influence have been established. The relationship between vibrodynamic and damping properties in these composites and atomic force microscopy data on the magnetic fillers restructuring under magnetic field action in a silicone elastomers matrix is discussed.
Changes in Mechanical Characteristics of HPC Samples Modified with WC and WO3 Nanopowder Agglomerates
Authors: Oleynik Artem , Derbasova Nadezhda , Gavrish Olga , Kharchenko Yevgeniy , Kraynov Aleksey
Published: February 2022

The paper presents the results of tests of HPC (high performance composites) samples consisting of aramid and glass fabrics modified by agglomerates of WC and WO3 nanopowders. According to the test results, introduction of WC and WO3 powders into the composite plate structure makes it more rigid and elastic, increasing its ability to dissipate energy.
Simulation of Hydro-Mechanical Billet Pressing of Fibrous Bimetallic Composites
Authors: Byvaltsev Sergey V. , Zalazinsky Aleksandr G. , Titov Vladimir G. , Shveikin Vladimir P.
Published: February 2022

The simulation of hydro-mechanical billet pressing of bimetallic composite is performed. Using mathematical modeling and simulation exercise, the influence of the main operational parameters, which include: draw-forming, the cone angle of the working die and the conditions of contact friction, on the strain heterogeneity, damage to the fibers (cores), and the extrusion stress, is studied. A method and an expert system were developed that allowed to carry out a computational experiment and a multi-criteria choice of rational values of the technological experiment is carried out. The results of the study are used to improve the industrial production of multi-core bimetallic wires for electrical purposes.
Relation of the Mayer Index to the Characteristics of the Power Law of Metal Hardening
Authors: Ogar Petr M. , Shilin Valery A. , Ugryumova Elena V.
Published: February 2022

The issues of determining the Mayer index depending on the parameters of strain hardening of an elastoplastic body described by the Hollomon equation are considered. The analysis of expressions connecting the engineering uniform deformation with the Mayer index is carried out. A new expression is obtained, a particular case of which is the result obtained by V.M. Matyunin et al. Applying the ratio of the maximum Mayer hardness to the Brinell hardness, the relationship of the ultimate strength to the Brinell hardness, and the Hollomon equation, a new expression of the Mayer law is obtained. The description of the radius of the contact area by a power function of the depth of the indenter insertion allowed us to represent the Mayer index as a ratio of known parameters obtained by finite element modeling for other purposes. The graphical dependences of the results obtained are presented.
Development of Technology for Producing Holes in Parts with Unpredictable Surface Fluctuations
Authors: Ryazantsev Alexander , Yukhnevich Sergey , Visotskiy Viktor
Published: February 2022

The article deals with the methods of forming liquid rocket engines parts, in which sheet material is used as a blank. The analysis of the existing methods of processing workpieces with a variable surface profile allows us to conclude that the mechanical method is the most promising type of processing for hole perforation. The drilling holes technology in parts made of sheet blanks is presented. The features of processing non-rigid parts with unpredictable surface fluctuations are considered. The ways of ensuring the stability of the treatment process, increasing the technological indicators, which allowed expanding the area of dimensional machining, are shown. The results of the work contribute to improving the manufacturability of new generations products of equipment, which is important for mechanical engineering.
Computational and Experimental Methods of Strength Analysis of Polyurethane Diaphragms Operating under Cyclic Loadings
Authors: Belyaev Leonid , Zhdanov Aleksey V. , Ivanchenko Aleksandr
Published: February 2022

In this paper, the algorithm for strength analysis of diaphragms made of elastomers is described, and the strength analysis of the diaphragm made of polyurethane "Vitur" T-1413-85 is carried out. The results obtained showed that the description of the material behavior using the Moony-Rivlin model (5 parameters) gives the greatest accuracy.
A comparison of the results of modeling the stress-strain state of the diaphragm and the experimental studies carried out to determine the displacements confirmed the adequacy of the chosen model (average correlation coefficient between numerical simulation and experiment R2 = 0.98) for both studied diaphragm thicknesses.
The conducted evaluation of the diaphragm resource according to the criteria of fatigue failure showed the correctness of the selected models of durability.
Production of Nanostructured Boron Carbide Ceramics for Industrial Applications
Authors: Eremeeva Zhanna V. , Kamali Saeed , Lizunov Artem I. , Ovchinnikov Vasiliy A.
Published: February 2022

The optimal modes (temperature, time, pressure force) of spark plasma sintering (SPS) and hot pressing of boron carbide obtained by various methods are determined. The initial powders were obtained from soot and amorphous boron by the mechanochemical synthesis method, by the high-temperature synthesis (SHS) method and by the carbon reduction method. The structure and the properties of SPS sintered and hot-pressed boron carbide blanks were determined. The highest value of the relative density was achieved during SPS sintering of blanks from B4C powders obtained by mechanosynthesis and SHS methods. It was found out the optimal conditions for sintering blanks from B4C powder obtained by mechanosynthesis. The density value reaches 99.0 rel.% at 1500 °C/25 MPa and sintering time of 45 min. For powders obtained by the SHS method, the density of sintered blanks is 98.5 rel.%. at 1800 °C/30 MPa with sintering time of 45 min. The highest value of the relative density was achieved during the hot pressing of blanks from B4C powders obtained by mechanosynthesis.
Thin Ni/Al Metal Films Characterization Using a High-Frequency Electromagnetic Field
Authors: Malikov Vladimir N. , Tihonskii Nikolay D. , Ishkov Alexey V.
Published: February 2022

The paper presents methods of obtaining and studying new materials - thin metal films of the Ni/Al system. The technique and main parameters of the resistive method of thermal evaporation of the alloy using a vacuum universal station are briefly presented. Samples of thin films of various thicknesses were obtained. The thickness of the material was determined both using a scanning electron microscope and a developed eddy-current gage system operating under a hardware-software complex. In the course of the research, the limit the film thickness gauging capabilities of the developed gage system was established (400 nm). The ability of the gage system to detect differences in the thickness of the same film was shown using the developed method. Also, the possibility of determining the thickness of an undoubtedly unknown thin film by an eddy-current transducer signal amplitude has been demonstrated.
Additive Technology for Forming Channels with Galvanic-Mechanical Coatings
Authors: Norman Anna , Smolentsev Vladislav , Norman Alexander , Starodubtsev Igor
Published: February 2022

A new additive technology for forming channels with galvanic-mechanical coatings is considered. The technological process of combined electroplating and mechanical processing of small diameter channels is compiled. Rational technological modes are defined.
Analysis of the Properties of the Fluidized Bed during the Formation of the Abrasive-Polymer Compound for Waterjet Cutting
Authors: Barsukov Gennady V. , Kozhus Olga G. , Danilchenko Stanislav G. , Petrukhin Anton V. , Titov Dmitry I. , Selemenev Konstantin F.
Published: February 2022

The authors of the article analyzed the properties of the fluidized bed during the formation of the abrasive-polymer compound for waterjet cutting. It is noted that in the process of applying the polymer shell to the surface of the abrasive grain in the fluidized bed, the effect of slippage and the absence of the influence of the installation wall on the value of the longitudinal velocity of particles near it is observed, which allows to increase the productivity of creating an abrasive-polymer compound.
Nonlocality of Dynamic Characteristics for Edge Dislocation Segment, Elastic Interaction of Dislocation with Pinning Points, and their Effect on Dislocation AIIF
Authors: Dezhin V.V.
Published: February 2022

In the present work, we studied dislocation amplitude-independent internal friction (AIIF) for segment of edge dislocation. Results obtained were compared with results of the Koehler-Granato-Lücke string model. Expression for dislocation effective rigidity and effective mass, obtained earlier by applying generalized susceptibility of dislocation, is used. Dependences of dislocation effective rigidity on dislocation segment length, dislocation effective mass on frequency and segment length, internal friction on for various values of frequency and segment length are plotted. Case of elastic interaction of the dislocation segment with pinning points is also investigated. It was found that main effect of elastic interaction the dislocation with the pinning points is reduces to influence in the effective rigidity. Plots of internal friction dependence on frequency for various values of distance between the dislocation and the pinning points are constructed.
Plastic Strain Localization in Steel Composites Produced via Additive Manufacturing
Authors: Nadezhkin Mikhail V. , Orlova Dina V. , Barannikova Svetlana A. , Zuev L.B.
Published: February 2022

In this work we report the kinetics of plasticity of St3 low-carbon steel-based composite alloy prepared via vacuum electron beam cladding of 09G2S steel wire. The digital image correlation method revealed the existence of macroscopic localization of plastic flow at the yield plateau and parabolic hardening stage. The kinetic characteristics of localized plasticity domains were measured in various composite layers, as well.
Research the Impulse Stamping Technology of High-Strength Hard-to-Form Alloys
Authors: Botashev Anvar Yu. , Musaev Abubakar A. , Betrakhmadov Ruslan V.
Published: February 2022

This article is devoted to expanding the technological capabilities of the gas-forming stamping method by increasing the pressure of combustion products acting on the surface of a workpiece stamped. Therefore, a scheme of a two-chamber device and a method for compressing the fuel mixture is proposed. The essence of the method is that of carrying out the stamping products under the high gas pressure, which is created by compression and subsequent combustion of the gaseous fuel mixture. To ensure the compression of the fuel mixture, the device is equipped with two combustion chambers separated by a piston. Due to this method, the pressure rises sharply. Under the influence of the combustion products' pressure, the workpiece is intensely deformed and fills the cavity of the matrix. This method of sheet stamping, implemented on a two-chamber device, will increase the gas pressure on the surface of the forged workpiece to 70-80 MPa at a fuel mixture pressure of 1 MPa, which ensures stamping of a variety range of parts in almost all branches of small-scale production related to metalworking.
In Situ Phase Transformations in CrN/Cr-Сoated E110 Alloy under High Temperature
Authors: Syrtanov Maxim , Pirozhkov Alexey , Sidelev Dmitrii
Published: February 2022

The paper considers phase transformations in the E110 zirconium alloy with multilayer CrN/Cr coatings under linear heating up to 1250 °C with isothermal exposure for 20 min. The multilayer CrN/Cr coatings can decelerate Cr-Zr interdiffusion by formation of a barrier ZrN layer at the “coating-alloy interface” due to CrN decomposition at high temperature. The duration of barrier effect depends on a layer thickness of CrN/Cr multilayers. This effect results in a better corrosion resistance of the E110 alloy with multilayer CrN/Cr coatings under high-temperature oxidation at 1100 °C in air in comparison with Cr-coated E110 alloy.
Changes in Wettability and Corrosion Properties of Coatings Obtained on MA8 Magnesium Alloy after Accelerated Climatic Tests
Authors: Nadaraia Konstantine V. , Mashtalyar Dmitry V. , Gerasimenko Mariia S. , Piatkova Mariia I. , Sinebryukhov Sergey L. , Gnedenkov Sergey V.
Published: February 2022

In the presented study, changes in the wettability and corrosion properties of composite coatings formed on the MA8 magnesium alloy by plasma electrolytic oxidation (PEO) with subsequent treatment with organofluorine polymers were investigated after accelerated climatic tests in a salt spray chamber. It was found by the sessile drop method that after accelerated climatic tests the contact angle decreases by 2.5 times for PEO coatings, and by 15o for composite coatings. Evaluation of the electrochemical properties of the composite layers revealed an insignificant decrease in the value of the corrosion current density after 40 days of holding samples in a salt spray chamber.
Quantitative Evaluation of the Effectiveness of Laser Surface Modification Technologies
Authors: Belashova I.S. , Marinin Evgeny A. , Sergeev Denis G.
Published: February 2022

Two new parameters – reduced wear and reduced integral microhardness of the modified surface layer was used to evaluate the effectiveness of surface hardening technologies. The existence of a correlation between the entered parameters is shown, the regression equation is obtained based on the analysis of experimental data of the wear of a tool made of steel CrWMn and U10 treated with a laser with coatings in the reflow mode. We construct the functional dependence of tool wear on this parameter.
The Impact of Cutting Modes on the Output Turn-Milling Parameters for High-Speed Steel
Authors: Matlygin Georgy , Savilov Andrey , Pyatykh Aleksey , Timofeev Sergey
Published: February 2022

The article describes the orthogonal turn-milling technology applied for powder high speed steels. The cutter with carbide inserts was used in the experiments. The orthogonal turn-milling model was developed to improve the surface quality by choosing optimal cutting modes based on the simulation results. The mathematical model makes it possible to predict geometric surface deviations. The impact of cutting speed, tool feed and radial depth of cut on the geometric surface parameters was identified. The results make it possible to achieve the satisfactory level of surface quality without deteriorating the machining productivity. The avenues for further research are outlined.
Modeling of Technological Processes for the Deposition of Composite Plasma Coatings
Authors: Kravchenko Igor N. , Kuznetsov Yuri A. , Kartsev Sergey V. , Selemenev Michael F. , Makarov Ivan D. , Prokhorov Denis G.
Published: February 2022

The influence of various design and technological parameters of the process of plasma deposition of coatings on their quality is considered. In the process of research, regularities were revealed and relationships were established between the factors and criteria of technological processes, which make it possible to solve optimization problems when developing technological recommendations and improving the methods of applying plasma coatings. The results of the research are the obtained mathematical models that can be applied to analyze the influence of individual factors, as well as their combination on the quality indicators of the process of forming coatings with given physical and mechanical properties.
Numerical Simulation of the Stress-Strain State of a Hybrid Titanium-Polymer Composite Material for Optimizing the Design of Aircraft Structures
Authors: Nasonov Fedor Andreevich , Kharchenko Kirill Dmitrievich , Akulinin Alexander Olegovich , Morozov Boris Borisovich
Published: February 2022

Work on the current topic of hybrid titanium-polymer composite materials (TPCM) is continuing. After checking the technological feasibility of two-stage processes for manufacturing parts of flat shapes and with a single curvature, identifying opportunities for improving the adhesive interaction, work is carried out to assess the possibility of varying design parameters, such as reinforcement schemes, combinations of components, etc.in order to obtain optimal properties of manufactured parts.
Numerical Simulation of Shrinkage Porosity during Casting Process
Authors: Dubrovskaya Aleksandra , Dongauzer Konstantin , Nikolaeva Natalya
Published: February 2022

At present the production paradigm undergoes a fundamental change when testing of actual units involving castings manufacturing gives way to digital simulation which allows to overcome constraints intrinsic to the traditional methods of trials and errors. This article presents the work on numerical study and prediction of shrinkage porosity in Nickel alloys castings made by precision casting method for further comparison of simulation results with the size of flaws produced during actual hardware testing.
Determination of the Optimal Temperature for Processing Styrofoam with a Thermo-Tool
Authors: Rivkin Alexey V. , Sobolev Alexandr N. , Nekrasov Alexey Ja. , Arbuzov Michael O.
Published: February 2022

It was carried out the research of variation of foam polystyrene hardness, and was observed the limiting temperature which take enable to cut the foam polystyrene with the use of thermo-tools.
Preparation of Carbidostals
Authors: Savinykh Leonid M. , Dudorova Tatyana A.
Published: February 2022

The article discusses a powdered material - carbidostal. Comparative characteristics of carbidostals, tool steels are given and hard alloys. Methods of producing and producing carbidostals are considered. Conditions for free separation of residues of impregnating material from the surface of the article are established. The reasons of volumetric change of amount of carbides and binding by height of impregnated press are studied.
Modeling of Molten Metal Flows in a Continuous-Casting Machine Mold at Free Rotation of the Floating Closed-Bottom Nozzle
Authors: Odinokov V.I. , Evstigneev A.I. , Dmitriev E.A. , Aleksandrov S.Yu. , Usanov G.I.
Published: February 2022

Currently, mathematical modeling applying numerical methods is widely used in the study of metallurgical processes, including metal casting processes in continuous-casting machines. The authors developed a new technology and device for casting metal into a continuous-casting machine mold and metal mixing using the effect of a rotating closed-bottom submerged nozzle with eccentric holes. The theoretical study of processes of mold filling with molten metal was carried out applying a proven numerical method and a special software package. A calculation program was developed based on the numerical schemes and algorithms. The results of calculating metal casting into a rectangular mold are presented as an example. The calculation results are provided in the form of molten metal flow patterns in various sections of the mold.
The Model of Local Fracture on Brittle Material Surface during Machining
Authors: Ogorodnikov A.I.
Published: February 2022

Brittle materials such as ceramics, glass or single-crystal silicon are extensively used for industrial applications and recently become an object of actual research due to the development of new products and technologies. In cases, where special attention is paid to the surface layer, mechanical processing with a diamond tool is of interest as one of the most efficient technology to manufacture products from brittle materials. In this paper, simulation method is presented, which allows to estimate an effect of cutting force on the size of defects zone formed in a hard brittle plate during machining. In the proposed model, there is a distinguished surface layer, which can have its own unique properties that differ from the properties of the brittle plate. In this work, the ANSYS finite element program is used to simulate the technological processes and solve the problem of stress distribution in a quasi-static formulation.
Influence of the Titanium Nitride Deposition Duration during Vacuum Ion-Plasma Treatment on the Resistance of Coatings in a Hydrogen Atmosphere
Authors: Gvozdeva Olga , Shalin Alexey V. , Stepushin Aleksander S. , Sarychev Sergey M.
Published: February 2022

In this work, the insulating properties of nitride coatings against the hydrogen penetration into semi-finished or finished products made of VT6 titanium alloy during hydrogenation annealing have been studied. It has been established that an increase of the duration of titanium nitride deposition for more than 30 minutes leads to the formation of pores and cracks in the coating and, as a consequence, to a decrease in the «protective» properties of such coating. It is shown that during linear gradient structure creation, the nitride coating effectively “protects” alloy from penetration of up to 0.5 wt%. of hydrogen.
Use of Hidden Phase Transfer Heat for Temperature Stabilization in Technological Cutting Systems
Authors: Dubrov Dmitry Yu.
Published: February 2022

This paper describes a temperature stabilization method in dry metal cutting. Using a hidden phase transfer heat allows to significantly reduce the wear rate. The tool holder design with porous evaporative cooling system is presented. Dependences of tool life of cutters on the cutting speed without cooling and with porous cooling are shown. This approach could be advantageous for the cutting of hard materials (titanium alloy).
Development and Research of Composite Coatings of Ti-B System, Sprayed by Microplasma Method
Authors: Goshkoderya Mikhail Evgenievich , Bobkova T.I.
Published: February 2022

The paper presents the results of development and study of a composite powder of Ti-TiB2 system. Comprehensive studies of composite coatings formed by microplasma spraying of the developed powders are carried out. It is determined that the developed composite materials are promising for use in elements and friction units of wind power plants and shipbuilding engineering objects.
Carbon Nanomaterials in Electrochemical Coatings of Machinery Products
Authors: Dyakov Igor A. , Safronov Ivan S.
Published: February 2022

The questions of application of nanomaterials in mechanical engineering are considered. Concept of electrochemical processing products in mechanical engineering with the use of a solid nanodisperse phase is defined. The characteristics and methods of application in the processes of electrodeposition of carbon nanomaterials are determined. The results of experimental investigations of electrolytic chrome plating with multi-walled carbon nanotubes of the "Taunit" series are presented.
Characterisation of seriousness and outcome of adverse drug reactions in patients received cancer chemotherapy drugs – A prospective observational study
Authors: Fatmi Syed Meraj , Bagati Kavita Dhar , Dutta Shaktibala , Sharma Jyotsna
Published: February 2022

Background:

Cancer chemotherapeutic drugs are commonly associated with serious adverse effect which contributes to increase in the duration of hospitalisation and economic burden.

Aim:

The aim of this study was to characterise the seriousness and outcome of adverse drug reactions (ADRs) produced by chemotherapy drugs in cancer patients.

Materials and Methods:

Patient's demographic characteristics and ADRs due to chemotherapeutic drugs were documented inpatient case report form. Frequencies of the seriousness of the ADRs, its outcome and preventability were studied using descriptive statistics. Proportion of life-threatening ADRs and ADRs linked to increase in duration of hospitalisation were studied. Factors associated with serious ADRs and patient characteristics were studied using calculation of odds ratio (OR) at 95% confidence interval (P < 0.5).

Results:

A total of 412 ADRs were noted in selected 120 patients received chemotherapy drugs. Majority of ADRs (61%) were linked to increase in duration of hospital admission. Some ADRs (12%) were noted as life-threatening to the patients. OR 1.58 was found on the association between patient age group and serious ADRs (P = 0.02). Association of preventability of ADRs and serious ADRs shows OR of 3.65 (P = 0.0001). Common serious ADRs were noted as anaemia, neutropenia, fever, thrombocytopenia, diarrhoea, mucositis and nausea and vomiting.

Conclusion:

The incidence of serious ADRs due to chemotherapy drugs amongst cancer patients is high. Studies on the nature of seriousness of ADRs, outcome and its triggering factors may help to prevent them. Early identification of serious ADRs may support to reduce hospital stay and economic burden.
Remarkable response to radiation therapy with concurrent chemotherapy in Stewart–Treves syndrome
Authors: Katano Atsuto , Yamashita Hideomi
Published: February 2022

Stewart–Treves syndrome (STS) is a rare, cutaneous angiosarcoma associated with chronic lymphedema. The prognosis of this syndrome is extremely poor, with a median survival time of 5–8 months, if untreated. An 82-year-old Asian woman noticed a painless elastic mass with partial discoloration (purplish discoloration) on the left thigh. She had lower lymphedema for 15 years. Lesion biopsy and immunohistochemistry analysis led to the diagnosis of angiosarcoma, which was considered to be STS. She was referred to our department for concurrent chemoradiotherapy. Radiation therapy consisted of 25 daily fractions of 2 Gy each (prescription dose: 50 Gy). Concurrent chemotherapy consisted of 2 monthly cycles of docetaxel (75 mg/body on day 1) and recombinant interleukin-2 (700,000 units/body on days 1–5). She experienced acute adverse events such as Grade 2 dermatitis, Grade 2 anemia, and Grade 4 leukopenia. Posttreatment computed tomography images revealed that lesions had disappeared. Moreover, the accumulation patterns on positron emission tomography images were markedly weakened after the treatment. She exhibited no signs of recurrence for 4 years.
Multifocal Unilateral Wilms’ Tumor: Radiopathological Correlation
Authors: Reddy Ravikanth
Published: February 2022

Wilms’ tumor constitutes majority of malignant primary renal tumors in children. Outcomes of treatment are excellent in Wilms’ tumor, with a cumulative survival rate of 87%. A combination of imaging and histopathology is needed for confirmation of Wilms’ tumor. However, imaging alone can be used for screening, diagnostic workup, assessment of response to treatment, preoperative evaluation, and follow-up for recurrence. In malignant primary tumors such as Wilms’ tumor, where the outcomes following treatment are excellent, management strategies are aimed at risk-based stratification approach, thereby improving the quality of life in children with high-grade tumors while maintaining extremely good outcomes in the pediatric age group with low-grade tumors. This case report describes a rare sonological appearance of multifocal unilateral Wilms’ tumor in a 4-month-old infant.
Atypical Chest Radiological Feature in a Patient with nCOVID-19
Authors: Sharma M. Vishnu , Anupama N.
Published: February 2022

Classical high-resolution computed tomography (HRCT) pattern in nCOVID-19 pneumonia is bilateral, basal, peripheral, subpleural, bronchopneumonia. Ground-glass opacities and consolidation are the most common initial radiological findings. However, chest computed tomography (CT) should not be used as an independent diagnostic tool to exclude or confirm COVID-19. CT is not a standard diagnostic tool for the diagnosis of COVID-19, but CT findings help to suggest the diagnosis in the appropriate setting. Chest CT findings should be correlated with epidemiologic history, clinical presentation, and reverse transcriptase–polymerase chain reaction (RT-PCR) test results. Many other diseases can mimic nCOVID-19 in HRCT and vice versa. We report an atypical radiological feature in RT-PCR-confirmed nCOVID-19 pneumonia case. HRCT showed unilateral peripheral ground-glass opacity. Atypical HRCT features in nCOVID-19 described in literature include central involvement, peribronchovascular involvement, isolated upper lobe involvement, nodular opacities, lobar consolidation, solitary opacity, unilateral lung involvement, mediastinal adenopathy, cavitory lesions, pleural and pericardial effusion, and subpleural sparing. When radiological manifestations are atypical, diagnosis of nCOVID-19 pneumonia should be by exclusion of other causes for the radiological abnormality.
A Giant Colonic Submucosal Lipoma: An Uncommon Cause of Colo-Colonic Intussusception with Review of Literature
Authors: Chandanwale Shirish Sahebrao , Sutreja Diva , Yadav Shraddha
Published: February 2022

ABSTRACT

Intestinal intussusception is a rare condition in adult. The early diagnosis is challenging and has chronic or acute subacute course. They often present with nonspecific symptoms. Colo-colonic intussusception in adults is often caused by malignant lesions colonic lipomas are rare mesenchymal tumors and the majority are asymptomatic and their size is usually <2 cm. Giant submucosal lipomas in sigmoid colon are rare mesenchymal tumors and rarely cause colo-colonic intussusception. Abdominal computed tomography and colonoscopy are the choice of modalities for preoperative diagnosis. Segmental colonic resection with lipoma is the choice of therapy in elderly males with symptomatic and larger submucosal lipoma.
Correlation between balance performance and perception about the knee in patients with osteoarthritis knee
Authors: Bhole Harshita , Ray Manish , Shyam Ashok , Sancheti Parag
Published: February 2022

BACKGROUND:

Static and dynamic balance impairment is seen in multiple cases of knee osteoarthritis (OA). The affection of body perception has also been observed. Balance and body perception are an integral part while performing daily activities. The affection of these further leads to fear of fall. The aim of this study was to find the relation between balance and knee body perception in primary OA knee patients.

METHODS:

This was a correlational study. Seventy-three patients with primary knee OA were recruited from tertiary care hospitals. Kellgren–Lawrence Grading system (I-IV) was used to assess the severity of knee OA. Patients having pain on the Visual Analog Scale 6/10 or below were included. The Fremantle Knee Awareness Questionnaire was used to assess a patient's body perception about the osteoarthritic knee. Static balance was assessed using four-stage balance test. Dynamic balance was assessed using the Timed Up and Go test.

RESULTS:

Statistical analysis was performed using Spearman's Correlational test to investigate the correlation between balance performance and knee body perception. The study included 73 patients within 45–80 years (59.4 ± 9.0). An overall strong positive correlation was obtained between balance performance and knee perception (r = 0.76, P = 0.00). Based on the OA grades, this correlation was moderate (r = 0.62, P = 0.00) in mild OA, moderate (r = 0.47, P = 0.05) in moderate OA, and strong (r = 0.71, P = 0.02) in severe OA.

CONCLUSION:

In knee OA patients, positive correlation exists between balance performance and knee body perception. As the severity of the disease increases, there is more impairment in balance and body perception. This affects the physical performance, quality of life in knee OA patients.
Effect of COVID-19 crisis on mental health of physiotherapy students
Authors: Tiwari Sapna Santosh , Mitra Suroshree , Dabadghav Rachana
Published: February 2022

CONTEXT:

COVID-19 outbreak has disrupted the lives of many people. The lockdown imposed from March 2020 in India, a necessary step taken for containment of the coronavirus infection, also had its effect on students' social and academic life. Along with many individuals, the student population has also gone through a range of psychological and emotional reactions due to uncertainty, lack of financial stability, academic delay, lack of physical contact with family members, friends, and constant overloading of information via social media.

AIMS:

The study was conducted to determine the effects of the COVID-19 crisis on the mental health of physiotherapy students.

SETTINGS:

Community (online).

DESIGN:

Survey study-Questionnaire based.

SUBJECT AND METHODS:

An online survey was conducted via Google forms consisting of demographic data and Depression Anxiety Stress Scale (DASS)-21 questionnaire (a shorter version of DASS41) having seven questions each subscale, i.e., depression, anxiety, and stress. The data were collected from June 22, 2020, to July 3, 2020.

STATISTICAL ANALYSIS USED:

Descriptive analysis of the data obtained was performed.

RESULTS:

A total of 275 physiotherapy students participated in the study. About 34.6% of students were found to have depression, 31.1% have anxiety, and 16% have stress in the range of mild, moderate, severe, and extremely severe. Majority were in mild category of depression, anxiety, and stress. 4th-year students were found to be more affected as compared to other students.

CONCLUSIONS:

COVID-19 crisis has affected the mental health of students.
Translation of shoulder pain and disability index in Gujarati language and analysis of its psychometric properties in persons with shoulder pain
Authors: Bhatt Vidhi Paras , Shah Nehal , Bhrambhatt Krishna M. , Kapadia Dharti
Published: February 2022

BACKGROUND:

Shoulder pain and disability index (SPADI) is a joint specific tool that helps to estimate the pain and disability in persons with shoulder pain. It is a self-administered index consisting of 13 items divided into two subscales: pain and disability. The study aims to find inter- and intra-rater reliability and concurrent validity of Gujarati version of SPADI (SPADI-G) in persons with shoulder pain in Gujarati population. SPADI-G can prove to be helpful in objectively defining the pain and disability in persons with shoulder pain.

MATERIALS AND METHODS:

A prior permission was taken from original author for translation of SPADI into Gujarati language. The translation procedure was carried out according to the guidelines provided by the WHO with forward and backward translation. The psychometric properties were analyzed in 20 persons (mean age of 52.65 ± 7.76) with different shoulder pathologies. Informed oral consent was taken from persons before the study. The validity was obtained by correlating SPADI-G and visual analog scale (VAS). The intrarater reliability was established by test–retest method within a span of 2 days. The questionnaire was again administered after 1 week by two different investigators to test the interrater reliability.

RESULTS:

The concurrent validity was established with a positive correlation with moderate strength between SPADI-G and VAS (Pearson's coefficient of correlation: r = 0.587, P < 0.01). The intrarater reliability was found between 0.853 and 0.977 (intraclass correlation coefficient [ICC] = 0.943) and interrater reliability was found between 0.914 and 0.983 (ICC = 0. 959). There was a high internal consistency with Cronbach's alpha = 0.967. The Bland–Altman plot analysis was performed for SPADI-G scores in between the two raters, which showed agreement between the two scores within the limits of agreement with 95% confidence interval. The linear regression showed no proportional bias.

CONCLUSION:

The results show good validity with moderate correlation between VAS and SPADI-G and excellent inter- and intra-rater reliability for SPADI-G in persons with shoulder pain.
Rectifiability of the reduced boundary for sets of finite perimeter over $\operatorname{RCD}(K,N)$ spaces
Authors: Bruè Elia , Pasqualetto Enrico , Semola Daniele
Published: February 2022

This paper is devoted to the study of sets of finite perimeter in

\operatorname{RCD}(K,N)

metric measure spaces. Its aim is to complete the picture of the generalization of De Giorgi’s theorem within this framework. Starting from the results of Ambrosio et al. (2019) we obtain uniqueness of tangents and rectifiability for the reduced boundary of sets of finite perimeter. As an intermediate tool, of independent interest, we develop a Gauss–Green integration-by-parts formula tailored to this setting. These results are new and non-trivial even in the setting of Ricci limits.
Pediatric COVID-19 Risk Factors in Southeast Asia-Singapore and Malaysia: A Test-Negative Case–Control Study
Authors: Wong Judith Ju Ming , Gan Chin Seng , Kaushal Sanghvi Heli , Chuah Soo Lin , Sultana Rehena , Tan Natalie Woon Hui , Eg Kah Peng , Thoon Koh Cheng , Lee Jan Hau , Yung Chee Fu
Published: February 2022

There is a scarcity of population-level data of pediatric COVID-19 infection from Southeast Asia. This study aims to describe and compare epidemiological, clinical, laboratory and outcome data among pediatric COVID-19 cases versus controls in two neighboring countries, Singapore and Malaysia. We used a test-negative case–control study design recruiting all suspected COVID-19 cases (defined by either clinical or epidemiological criteria) from January 2020 to March 2021 admitted to two main pediatric centers in Singapore and Malaysia. Data were collected using a standardized registry (Pediatric Acute and Critical Care COVID-19 Registry of Asia). The primary outcome was laboratory-confirmed COVID-19. Univariate and multivariable logistic regression analysis was used to determine factors associated with COVID-19. This study included 923 children with median age of 4 (interquartile range 2–9) years. Of these, 35.3% were COVID-19 cases. Children with COVID-19 were more likely to be asymptomatic compared with controls (49.4 versus 18.6%; P < 0.0001). They were also less likely to develop respiratory complications, such as bronchitis or pneumonia, or organ dysfunction. Four (1.2%) of our COVID-19 patients required respiratory support compared with 14.2% of controls needing respiratory support. COVID-19 cases tended to have lower neutrophil count but higher hemoglobin compared with controls. There were no reported deaths of COVID-19 infection; in contrast, 0.7% of the control group died. In the multivariable analysis, older age, travel history, and close contact with an infected household member were associated with COVID-19 infection. This study shows that the majority of pediatric COVID-19 cases were of lesser severity compared with other community acquired respiratory infections.
INFLUÊNCIA DOS PERFIS DE PROFISSIONAIS DE EMPRESAS GESTORAS NO DESEMPENHO DE FUNDOS DE INVESTIMENTO À LUZ DA TEORIA DA SINALIZAÇÃO
Authors: Correia Thamirys De Sousa , Costa Ingrid Laís De Sena , Lucena Wenner Glaucio Lopes
Published: February 2022

A pesquisa teve como objetivo investigar a influência dos perfis de profissionais das equipes executivas e de gestão de empresas gestoras no desempenho de fundos de investimentos no Brasil, à luz da teoria da sinalização, entre os anos de 2011 a 2015. Coletou-se as informações sobre perfis de executivos e gestores, a variável de desempenho dos fundos (Índice de Sharpe) e as variáveis de controle por meio dos 'Anuários da Indústria de Fundos de Investimento' e da Comdinheiro. Os resultados mostram que 51,70% dos gestores do sexo masculino apresentaram relações positivas com o Índice de Sharpe quando os fundos são analisados conjuntamente (Renda Fixa, Fundos de Ações e Multimercado), todavia ao analisar os fundos de forma separada, por meio de suas classes, não foi observada significância estatística, não sendo possível ter um resultado conclusivo sobre a diversidade de gênero. Ademais, a formação em área de negócios não influenciou no índice de desempenho, contudo houve relações positivas e significantes entre ‘anos de instituição’ e Índice de Sharpe quando se analisa as classes de fundos conjuntamente ou apenas os Fundos de Multimercado. Outrossim, a variável 'anos de mercado' influenciou de forma negativa no Índice de Sharpe, havendo como explicação o fato de os profissionais experientes se preocuparem com a sua reputação e por isso tomarem decisões que podem impactar nos rendimentos de cotistas. Posto isso, informações de baixo custo como ‘anos de instituição’ e 'anos de mercado' contribuem para os investidores na seleção de altos executivos e gerentes.
TRÊS VISÕES SOBRE ÉTICA E EVASÃO FISCAL: COMO SE POSICIONAM OS ESTUDANTES DA ÁREA DE NEGÓCIOS?
Authors: Cruz Felipe Rodrigues , Paiva Ana Clara Ventura , Cunha Jacqueline Veneroso Alves da , Barbosa Neto João Estevão
Published: February 2022

A evasão fiscal é um problema comportamental que ameaça a capacidade do governo de levantar receitas. Porém, ainda são poucos os trabalhos que examinam a não-conformidade com as obrigações tributárias sob um olhar ético. Na literatura sobre o tema, emergiram três visões relacionadas à ética da evasão fiscal. A primeira assume que a evasão nunca é ética. A segunda assume que a evasão é sempre ou quase sempre ética. A terceira visão está associada à noção de que a evasão não é absolutamente antiética. Nesse sentido, o presente trabalho teve por objetivo investigar como 195 estudantes dos cursos de Administração, Ciências Contábeis e Economia de Universidades Federais de Minas Gerais se posicionam em relação a essas três visões, partindo do modelo de McGee, Ho e Li (2008), que apresenta 15 afirmações sobre a evasão fiscal. Os estudantes foram classificados de acordo com sua visão por meio de uma análise de cluster e analisaram-se as associações de variáveis como idade, sexo, etc. com cada um dos grupos formados. Após a realização de uma análise de cluster, constatou-se que a maioria dos estudantes foi posicionada no grupo que considera a evasão como sempre antiética, enquanto a menor parte considera a evasão como ética. Constatou-se que as mulheres são menos propensas à evasão fiscal e que indivíduos de maiores faixas de idade são menos propensos a enxergar a evasão como ética. Em relação aos cursos, percebeu-se que os alunos de Ciências Contábeis são menos propensos à evasão fiscal em relação aos alunos dos cursos de Administração e Ciências Econômicas. Por fim, sintetizaram-se as visões de cada um dos grupos por meio da análise do Discurso do Sujeito Coletivo.
O IMPACTO DA OCPC 07 SOBRE O TAMANHO E A LEGIBILIDADE DAS NOTAS EXPLICATIVAS DE COMPANHIAS BRASILEIRAS
Authors: Gomes Matheus Da Costa , Ferreira Rafael Ribas , Martins Vinícius Aversari
Published: February 2022

A divulgação de informações irrelevantes em Notas Explicativas (NEs) vem acarretando em demonstrativos financeiros longos e de difícil leitura. Como forma de aumentar a qualidade das NEs, com ênfase no princípio da relevância, o Comitê de Pronunciamentos Contábeis (CPC) emitiu em 2014 a Orientação Técnica – OCPC 07 – Evidenciação na Divulgação dos Relatórios Contábil-Financeiros de Propósito Geral. Para verificar os eventuais efeitos da publicação da OCPC 07 sobre o tamanho e a legibilidade das notas explicativas de companhias brasileiras, este trabalho utilizou-se de técnicas de mineração de textos e de quantificação de elementos textuais para a coleta de dados em NEs. Por meio de softwares específicos, as empresas listadas no Novo Mercado foram analisadas com testes de diferença de médias e um modelo de regressão linear, no que tange às quantidades de páginas, caracteres, palavras, sílabas, frases, parágrafos e tempo estimado de leitura, comparando as NEs anuais de 2013 com as de 2014. Os resultados mostram que a grande maioria das empresas reduziu o tamanho de suas NEs e que as empresas que fizeram menção à OCPC 07 apresentaram uma redução ainda maior do que as demais. Em números absolutos, houve uma redução média total de 6,5 páginas; para as empresas que citaram a OCPC 07, a redução foi de 13 páginas. Os resultados indicam que as NEs ficaram menores, porém não mais fáceis de serem lidas. Com a utilização do índice de legibilidade de Flesch, observou-se que os níveis de qualidade de escrita não se alteraram após a orientação técnica. A relação positiva entre tamanho e legibilidade evidencia a dificuldade de diminuir o volume de NEs e, ao mesmo tempo, aumentar a qualidade de leitura das mesmas, o que pode ser um obstáculo para o alcance de melhores níveis de disclosure contábil.
MODELO DE AVALIAÇÃO DE RENTABILIDADE DE ATIVOS – CINCO FATORES
Authors: Bittencourt Wanderson Rocha , Júnior José Bonifácio de Araújo
Published: February 2022

Modelos para analisar o retorno de ativos vêm sendo estudados ao longo dos anos. Um modelo recentemente desenvolvido foi o de cinco fatores proposto por Fama e French (2015). Tal modelo inclui variáveis relacionadas à rentabilidade e investimento a sua proposta anterior, modelo de três fatores (relação valor patrimonial/mercado, tamanho e o beta (medindo a sensibilidade do ativo em relação a carteira de mercado)). Neste cenário, a presente pesquisa buscou analisar o comportamento do modelo de cinco fatores ao contexto brasileiro. A partir das empresas listadas na Bolsa, excluindo o segmento financeiro foram construídas 25 carteiras utilizando dados trimestrais entre o segundo trimestre de 2007 até o primeiro trimestre de 2017, totalizando 40 períodos, para estimar três regressões com dados em painel (CAPM, modelo de três e cinco fatores). Os resultados mostraram que ainda existem variações não explicadas pelo modelo, apresentando em alguns momentos interceptos significativos, contradizendo as premissas básicas do CAPM. Contudo, observa-se pelos resultados que existem ainda distorções provocadas pela taxa livre de risco utilizada. Há de ser destacado que os retornos das ações de empresas pequenas parecem não ser superiores aos das grandes empresas, como prevê a teoria, devido à elevada exposição ao risco. Neste contexto, os resultados são contrários aos resultados esperados pelo modelo analisado. Observa-se também uma melhora no poder de explicação com a inclusão de mais dois fatores em detrimento aos modelos anteriormente testado. Sugere ainda a possibilidade de aprimoramento do modelo ao não captar anomalias de momento.