bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic density of the sclera of keratoconus eyes and its clinical significance
Authors: Tarutta E. P. , Khandzhyan A. T. , Kiseleva T. N. , Milash S. V. , Ivanova A. V. , Guryanova O. V. , Markosyan G. A. , Bedretdinov A. N. , Ramazanova K. A.
Published: March 2023

Purpose: to assess the biophysical properties of the sclera by measuring its acoustic density in keratoconus, highly myopic, and healthy eyes. Material and methods. We examined 34 patients (67 eyes) aged 15–45 with keratoconus of various stages, 15 patients (30 eyes) aged 17–28 with high myopia and 15 people (30 eyes) aged 28–37 without ophthalmic pathology. The acoustic density of the sclera (ADS) was measured on the Voluson Е8 ultrasound device (GE Healthcare, USA) in the posterior eye pole (ADS-1) and in the equatorial area (ADS-2). The axial length (AL) of the eye, corneal thickness (CT), anterior chamber depth (ACD), and lens thickness (LT) were determined using Galilei G6 (Ziemer Group, Switzerland). The vitreal chamber depth (VCD) was calculated according to the formula: VCD = AL – СT – ACD – LT. Results. In keratoconus patients, the average ADS-1 value was 242.5 ± 7.4 conventional units (CU), ADS-2 averaged 234.1 ± 12.1 CU, AL was 24.6±1.1 mm long, and VCD was 17.1 ± 0.4 mm. In high myopia group, the average value proved to be significantly lower: ADS-1 was 210.3 ± 15.7 CU, ADS-2 — 201.2 ± 11,2 CU, while AL and VCD were higher: resp. 27.0 ± 0.7 mm and 19.2 ± 0.5 mm (p < 0,05). In the control group (healthy eyes), ADS-1 was 247.5 ± 2.8 and ADS-2 was 238.1 ± 0.6 CU, which practically showed no difference to the keratoconus group (p > 0.05). AL was 23.7 ± 0.6 mm, and VCD was 16.0 ± 0.6 mm. An insignificant tendency toward ADS drop in keratoconus eyes with AL over 25.0 mm was observed. Probably, we are dealing here with a combination of keratoconus with axial myopia. Conclusion. The acoustic density of the sclera of keratoconus patients approaches the respective parameter of healthy eyes and is significantly higher than that of highly myopic eyes. The analysis of acoustic density of the sclera and vitreal chamber depth may be considered as a method of additional differential diagnostics of keratoconus and congenital myopia with high corneal refraction and astigmatism.
A new bacterial-derived biosurfactant for biotechnological applications in the oil industry: production, optimization, biosurfactant functional and physicochemical characterization
Authors: Elghoul Marwa , Bouassida Mouna , Ghribi Dhouha , Mnif Inès
Published: March 2023

Aiming the potential application of lipopeptide biosurfactant (BioS) in bioremediation, we studied its production by a novel, isolated strain of Bacillus sp. MI27. Using the experimental design methodology, a novel medium composed of 2% sucrose, 0.27% Na2HPO4, 0.2% ammonium sulfate, 0.02% NaCl, 0.02% CaCl2, 0.02% MgSO4, 0.001% MnSO4, 0.06% KH2PO4, 0.005% FeSO4 and 0.005% ZnSO4 was optimized. With this composition, strain MI27 produces 1.4 g/L BioS with maximum surface tension (ST) reduction of 23 mN/m and a dispersion diameter of around 10 cm. Emulsifying and foaming activities have been also confirmed. The critical micelle concentration (CMC) value was about 120 mg/L with corresponding ST of 23 mN/m. The dispersion and emulsification index (EI) were about 12 cm and 45% at 1,000 mg/L respectively. Moreover, the foaming capacity, stable over 1 h of incubation, was about 80% at 1,000 mg/L. Additionally, we studied the effect of different pH, temperature and salinities on MI27 BioS activity and stability. Obtained results showed interesting surface activities at extreme physicochemical conditions, especially at acidic and alkaline pH values, high and low temperatures and higher salinities. All these characteristics enable the possible application of BioS in water treatment biotechnology under diverse environmental conditions.
Profile of Women Seeking an Intra-uterine Contraceptive Device at a Community Health Centre in Pretoria, South Africa
Authors: AM Maphiri , Bongongo T
Published: March 2023

Background:

An upsurge in demand for intra-uterine contraceptive devices (IUCDs) has led to this study, which focuses on the profile of women seeking IUCDs at a community health centre in Pretoria, South Africa.

Aim:

The study aimed to determine the profile of women seeking IUCDs at a Pretoria community health centre.

Setting:

The setting was Temba Community Health Centre in region 2 of Tshwane health district, South Africa.

Methods:

A descriptive quantitative study with a cross-sectional design was conducted using a piloted questionnaire.

Results:

Among the 129 participants, the mean age was 35 years (minimum 17 years, maximum 46 years). High participation was noted in the age group of 30–39 years (57.4%), single women (42.6%), those unemployed (54.3%), those with a secondary education (69%), and those with two children (62.8%). The decision to use an IUCD was based on its invisibility, lack of daily or sexual activity-related reminders, and lengthy device lifespan (100%). Before using an IUCD, many participants (32.6%) used condoms, and they were well versed in the IUCD. The primary source of knowledge on the IUCD was healthcare professionals.

Conclusion:

Women seeking IUCDs at a Pretoria CHC were mainly in the age range of 30–39 years, single, unemployed, with two children, using condom, and knowledgeable about the IUCD. The decision to choose an IUCD was backed by three key factors: it is invisible, there is no need for a daily or sexual activity-related reminder, and it lasts a long time without requiring a visit to the doctor. Healthcare professionals were the primary source of knowledge about IUCDs, and the knowledge regarding the device was scored as good among users at Temba CHC.
DOES MILLENNIAL RATIONAL IN DECISION MAKING? THE IMPACT OF SELF-CONTROL AND E-MONEY ON COMPULSIVE BUYING: REFERENCE GROUP AS MODERATING VARIABLE
Authors:   Department of Management, Faculty of Economics and Business, Universitas Negeri Surabaya, Indonesia, Rahman Zainur , Santosa Awan ,   Department of Management, Faculty of Economics, Universitas Mercu Buana Yogyakarta, Indonesia, Sumiyarsih Sumiyarsih ,   Department of Management, Faculty of Economics, Universitas Mercu Buana Yogyakarta, Indonesia, Dwiarti Rina ,   Department of Management, Faculty of Economics, Universitas Mercu Buana Yogyakarta, Indonesia, Huddin Norlaile Salleh ,   Universitas Pendidikan Sultan Idris, Tanjong Malim, Perak, Malaysia
Published: March 2023

The millennial generation is known as the sandwich generation, whe­re they sometimes experience various problems in making decisions, including purchasing goods or services. These problems are essential to study re­garding decision-making, especially in the digital era. There are various con­ve­niences in conducting transactions, such as e-money. The millennial gene­ra­tion tends to compulsive buying for goods or services with various factors, both due to individual internal and external factors. This study aims to examine the effect of self-control and e-money on compulsive buying, which a referen­ce group moderates. The sampling technique used is purposive sampling with a total of 249 respondents, where the sample criteria are the younger generati­on with e-money applications. The data analysis technique uses SEM-PLS to test the hypothesis. The results showed that self-control weakened compulsive buy­ing due to the individual's ability to control himself in shopping. E-money usa­ge has a positive effect on compulsive buying because of easier tran­sac­ti­ons. The novelty of this study used the reference group as a moderating varia­ble, where the results of the reference group strengthen the influence of self-con­trol on compulsive buying because individuals get positive information and suggestion from the group. Finally, the reference group can weaken the in­flu­ence of e-money on compulsive buying. Although there is convenience in tran­sacting, the presence of information from the group can prevent them from compulsive buying.
ACHIEVING PERFORMANCE THROUGH STRATEGIC AGILITY AND ENTREPRENEURIAL INNOVATION: AN EMPIRICAL RESEARCH IN SMEs SECTOR
Authors:   Universitas Widyatama, Munawar Fansuri , Kaniawati Keni ,   Universitas Widyatama, Latifah Ifa ,   Universitas Widyatama, Buana Dwinto Martri Aji ,   School of Management, Department of Business Administration, National Taiwan University of Science and Technology, Taipei, Taiwan
Published: March 2023

Small and medium enterprises (SMEs) are often considered sig­ni­fi­cant in developing countries like Indonesia. However, there are several pro­blems regarding the quality of human resources and technical and non-tech­ni­cal skills, weaknesses in seizing opportunities, and lack of innovation. For this re­ason, SMEs need to be continuously developed both in quantity and quality, es­­pecially in improving their performance to contribute to economic de­ve­lop­ment. Therefore, this study examines the factors directly or indirectly related to improving its performance. This study empirically predicts that strategic agi­lity can influence entrepreneurial innovation and organizational learning. Fur­­thermore, this study proposes a relationship between strategic agility, en­tre­­preneurial innovation, and organizational learning on performance in SMEs. This research was conducted by taking samples from SMEs in the food and beverage, fashion, service, and other sectors. Sampling was conducted on 110 owners or managers of UKM in the Bandung, Garut, and Sumedang areas. Da­ta analysis in this study used SEM-PLS. The results show that strategic agi­li­­ty positively relates to entrepreneurial innovation and organizational learn­ing. Then, these findings show that organizational learning has the most sig­ni­fi­­cant influence on performance compared to strategic agility and entre­pre­ne­u­rial innovation. This study implies that SMEs can respond quickly to external cha­nges, find creative solutions, and have agile capabilities in work processes. Re­commendations for further research include environmental uncertainty mo­de­rating variables linking strategic agility and performance.
EXPERIENTIAL VALUE TOWARD BEHAVIORAL INTENTION OF LOCAL FOOD THROUGH CONSUMER ATTITUDE: INSIGHT FROM GEN Z'S IN JAKARTA
Authors:   Universitas Tarumanagara, Jakarta, Tjokrosaputro Miharni
Published: March 2023

Recently, there has been an increase in public excitement for cu­li­na­ry experiences, including local cuisine exploration. The wide range of Indone­sian cultures significantly impacts the variety of local food variations, which must be maintained. However, Indonesian Gen Z (27.94% of the overall po­pu­lation) prefers food from other cultures to their own. So, this study examines the role of experiential value as an antecedent of Generation Z's attitude to lo­cal food and its influence on behavioral intentions. This research will exa­mi­ne the role of consumer attitude as a mediator in the relationship between va­lues on the behavioral intentions of Gen Z in Jakarta towards local food. The re­search was conducted using convenience sampling through a questionnaire by a cross-sectional survey. The data were obtained from 130 respondents and pro­cessed further with SmartPLS. The test results show that the experience va­lue of Gen Z has a positive and significant effect on consumers' behavior and behavioral intentions toward local food. Thus, Gen Z's behavior has a po­si­tive and significant impact on the behavioral intention of Gen Z toward local fo­od. Experiential value has a positive effect on the behavioral intention of Gen Z towards local food, mediated by consumer attitudes. This research pro­vi­des input for local food entrepreneurs about the importance of experiential va­lue through the dimensions of customers' return on investment, aesthetics, and cheerfulness. The experiential value positively influences Gen Z's attitude and behavioral intentions toward local food. For academics, this research can ex­pand and enrich research in the food industry, especially local food.
MEASURING USER SATISFACTION AND NET BENEFIT OF SAKTI SYSTEM: LESSONS FROM STAKEHOLDERS OF REGIONAL TREASURY OFFICE IN RIAU PROVINCE
Authors:   Institut Bisnis dan Teknologi Pelita Indonesia, Rahayu Winarni , Sudarno Sudarno ,   Institut Bisnis dan Teknologi Pelita Indonesia, Komardi Dadi ,   Institut Bisnis dan Teknologi Pelita Indonesia
Published: March 2023

"User satisfaction" is always an important measure of a stakeholder's opinion of e-government and must cover the entire stakeholder experience. "Net benefits" are the most important success factor of implementation system information and can measure the balance of positive and negative impacts of the e-government like the SAKTI system. This study aims to analyze the influence of service quality, information quality, system quality, organizational support, and regulatory environment on user satisfaction and net benefits of SAKTI users. This quantitative study uses primary data in questionnaires distributed to respondents through google forms and interviews. The questionnaire used simple random sampling. The sample size in this study was 482. The data were analyzed by Structural Equation Modeling (SEM) using Partial Least Square (PLS), namely SmartPLS version 3.2.9. The hypothesis test results show that system quality significantly and strongly impacts user satisfaction. Information quality has a large and strong impact on user satisfaction. Service quality has a large and strong impact on user satisfaction. Organizational support has a small and weak impact on user satisfaction. The regulatory environment has a large and strong impetus for user satisfaction. User satisfaction, influenced by service quality, information quality, system quality, organizational support, and the regulatory environment, strongly impacts the net On Stakeholders of the Regional Treasury Office in Riau Province. The research model can use to conduct surveys of user satisfaction on SAKTI or other e-government and evaluate the results.
Generalized effective-field approximation for inhomogeneous medium with inclusions in multilayered shells
Authors: Lavrov I. V.  , Bardushkin V. V.  , Yakovlev V. B.
Published: March 2023

An approach is proposed for calculating effective physical characteristics of a inhomogeneous medium with several levels of nesting of its microstructure --- the generalized effective-field approximation. With the help of this approach, an expression is obtained for an effective permittivity tensor of an inhomogeneous medium with ellipsoidal inclusions in a multilayered shell, the boundaries of all layers of which are ellipsoids. The proposed approach allows to take into account probabilistic distributions of orientations and forms of inclusions, as well as the presence of several types of inclusions. Two cases of matrix composites are considered: 1) with spherical isotropic inclusions with a multilayered shell; 2) with ellipsoidal anisotropic inclusions with a multilayered shell. For an inhomogeneous medium with homogeneous inclusions, this approximation is shown to produce the same result as the generalized singular approximation. Keywords: inhomogeneous medium, composite, matrix, inclusion, multilayered shell, generalized effective-field approximation, generalized singular approximation, effective permittivity.
Generation of narrowly focused radiation of neutrons in a plasma-focus discharge --- discovery and prospects of research
Authors: Ablesimov V.E.  , Malkin A.G.  , Pasharina O.Y.
Published: March 2023

Analysis of the measurement results by scintillation detectors of the time dependence of the output of DD neutrons in a plasma-focus discharge indicates the generation of a narrowly directed neutron beam in the discharge. The quantitative characteristics of a narrowly directed neutron beam are estimated --- the output of neutrons in the beam, the duration of generation, and the angular divergence of the beam. To estimate the beam parameters, the Monte Carlo simulation of the features of the time dependence of the signal of the scintillation detector in the conditions of a closed space in which the measurements were carried out was carried out. Keywords: plasma focus, generation of DD neutrons, scintillation detectors, time-of-flight method, Monte Carlo method.
Autowave description of the temperature effect during deformation of FCC metals
Authors: Zuev L. B.  , Barannikova S. A.  , Kolosov S. V.
Published: March 2023

The data of comparative studies of the development of plastic flow in pure aluminum and iron-based austenitic alloy (Fe-Cr-Ni) are presented. Deformation patterns were studied during tests in the temperature range 143≤ T≤420 K. It was found that the effect of temperature is different for these two cases. When a stationary dissipative structure appears at the stage of parabolic strain hardening, the effect of temperature is determined by the change in the length of the localized plasticity autowave. At the stage of linear strain hardening, when a phase autowave of localized plasticity is formed, the effect is associated with an exponential increase in its rate with temperature. Keywords: plastic deformation, localization, metals, Debye temperature.
Influence of the sign of the zeta potential of nanodiamond particles on the morphology of graphene-detonation nanodiamond composites in the form of suspensions and aerogels
Authors: Rabchinskii M. K.  , Trofimuk A. D.  , Shvidchenko A. V.  , Baidakova M. V.  , Pavlov S. I.  , Kirilenko D. A.  , Kulvelis Yu. V.  , Gudkov M. V.  , Shiyanova K. A.  , Koval V. S.  , Peters G. S.  , Lebedev V. T.  , Melnikov V. P.  , Dideikin A. T.  , Brunkov P. N.
Published: March 2023

A new method of using the detonation nanodiamond with positive and negative zeta potential as a spacer for aerogels based on graphene oxide is presented. It is shown that the dosed addition of detonation nanodiamonds' particles to the suspension of graphene oxide hydrosol made it possible to triple the specific surface area of the resulting aerogel compared to graphene oxide aerogel, and this effect is more significant when nanodiamonds with a positive zeta potential are used. It was also shown that aerogels derived from graphene oxide and detonation nanodiamond with a positive zeta potential have a specific morphology with graphene oxide platelets being twisted. This effect is discussed in terms of the change in the average zeta potential of the initial mixtures. Keywords: two-component systems, carbon materials, colloid chemistry.
Evaluation of the thresholds of stimulated nonlinear scattered CW laser radiation in high-power fiber amplifiers
Authors: Slobozhanina M. G.  , Bochkova N. V.  , Bochkov A. V.  , Slobozhanin A. N.
Published: March 2023

The paper describes a new approach for determining the threshold for stimulated nonlinear scattering in active and passive optical fibers. It is proposed to fix the power of the Stokes component at a certain level, which will make it possible to determine the threshold values of laser radiation powers, which characterize the manifestation of stimulated nonlinear scattering at the expected power level, in a convenient way from the applied point of view. Verification of the obtained expressions is given. Keywords: stimulated nonlinear scattering, fiber amplifier, stimulated nonlinear scattering threshold.
Nonreciprocity of microwave propagation in the[(CoFe)/Cu]/(glass) system
Authors: Rinkevich A. B.  , Perov D. V.  , Milyaev M. A.  , Kuznetsov E. A.
Published: March 2023

The propagation of microwaves through the dielectric substrate/metal superlattice system [(CoFe)/Cu] has been investigated. The frequency dependences of transmission and reflection coefficients for the normal incidence of electromagnetic waves on the system in two opposite directions are measured. The effect of the substrate thickness on the magnitude of the microwave giant magnetoresistance effect during reflection and on nonreciprocity in the system is investigated. The influence of an external magnetic field on the nonreciprocity parameter is investigated. It has been established that under the conditions of nonreciprocity, the microwave giant magnetoresistance effect increases significantly when the wave is reflected. Keywords: metal superlattices, microwave giant magnetoresistance effect, microwaves, transmission and reflection coefficients, nonreciprocity.
Ion beam source upgrade of the neutron source at IAP RAS
Authors: Vybin S. S  , Izotov I. V  , Skalyga V. A.  , Palashov O. V.  , Mironov E. A.
Published: March 2023

The results of the ion source of the neutron generator upgrade, which makes it possible to operate in a CW mode, are presented. A magnetic trap consisting of permanent magnets (NdFeB) was developed. A 3-electrode extraction system equipped with a magnetic lens was used to extract the deuterium ion beam. Calculations are made for the formation of a deuterium ion beam with a current over 500 mA and an energy of 100 keV with practically no losses in the extraction system. Keywords: extraction system, magnetic trap, neutron generator, ion beam.
On the theory of nonlinear photoacoustic signal generation during gas-microphone detection
Authors: Salikhov T.Kh.  , Madvaliev U.  , Sharifov D.M.  , Tuichiev H.Kh.
Published: March 2023

A theory is proposed for of the generation of the first two harmonics of a nonlinear photoacoustic signal of a solids sample with an arbitrary value of thermal conductivity. For limiting cases (thermally thin and thick samples) has been obtained simple expressions for the dependence of the amplitude of the excited photoacoustic signal from the emissivity of the sample and the thermophysical parameters of the sample, gas and substrates, including their thermal coefficients. Keywords: photoacoustics, thermal nonlinearity, second harmonic.
On the possible mechanism of external infrasonic mechanical stimulating the process of formation of nanocrystals in an amorphous metal film
Authors: Slyadnikov E.E.  , Turchanovsky I.Y.
Published: March 2023

A kinetic model, a physical reason and a condition for stimulated by external infrasonic mechanical vibrations of the formation of nanocrystals in an amorphous metal film. The nanostructural elements of the amorphous medium are responsible for these processes: locally ordered nanoclusters and nanoregions containing free volume, which contain two-level systems. When glass is deformed, two-level systems are excited, due to which they make a significant contribution to inelastic deformation, structural relaxation, formation of nanoclusters and nanocrystals. The physical mechanism of nanocrystallization of metallic glass during mechanical exposure includes, in addition to the mechanism of local thermal fluctuations, also athermal mechanism of quantum tunneling of atoms or atomic groups stimulated by inelastic deformation. Keywords: Kinetic model, amorphous metal film, nanocrystals, infrasonic mechanical vibrations.
On the distribution of charge carriers in branches thermoelectric cooler
Authors: Markov O. I.
Published: March 2023

The simulation of energy conversion in the branches of a thermoelectric cooler is carried out. The influence of various distributions of the active impurity along the branch of the thermoelement on its efficiency in the mode of maximum temperature drop is considered. The calculation is carried out within the framework of a two-band standard model of the band structure of a semiconductor for non-degenerate charge carriers. The Thomson effect was not taken into account. Keywords:thermoelectric cooler, distributed Peltier effect, two-zone model, non-degenerate charge carriers, thermoelectric efficiency.
Improving the dissolution of lidocaine by dispersing the rapid expansion of supercritical solution
Authors: Kuznetsova I. V.  , Sandugey N. S.  , Gil'mutdinov I. I.  , Gil'mutdinov I. M.  , Sabirzyanov A. N.
Published: March 2023

An experimental study of the grinding of lidocaine by the rapid expansion of supercritical solutions (RESS method) was carried out. The experiments were carried out in the pressure range of 10-35 MPa and temperatures of 308-333 K. The analysis of the morphology and size of particles, as well as the effect of the process parameters on them, was carried out. Qualitative and quantitative spectrophotometric analysis was carried out. The dissolution test was carried out in a phosphate buffered saline medium simulating plasma, which showed that the reduction in particle size gave an increased yield of the drug in a shorter period of time compared to the original drug that was not treated. Keywords: supercritical fluid, microparticles, spectrophotometric analysis, lidocaine.
Physical principles of development of magneto-levitation systems based on the second generation high temperature superconducting composites (Review)
Authors: Rudnev I.A.  , Anischenko I. V.
Published: March 2023

An overview of experimental and theoretical studies of the characteristics of maglev systems using high-temperature superconductors (HTSC) is presented. Materials used in maglev technologies, namely bulk superconductors and HTSC tape composites, are considered. The main experimental data obtained on both bulk and tape superconductors assembled in stacks of various configurations are demonstrated. The factors influencing the magneto-force characteristics are analyzed: geometric parameters, the influence of external alternating magnetic fields, temperatures, relaxation phenomena. A significant part of the review is devoted to the description of various methods for calculating maglev systems, including those based on stacks of HTSC composites. The features of thermal processes in maglev systems with cryocooler and nitrogen cooling are considered. General recommendations for the creation of optimal maglev systems based on tape HTSC composites are given. Keywords: magnetic levitation, high-temperature superconductors, strip composites, levitation force, lateral force, methods for calculating magnetic force characteristics.
Plasma electron temperature measurement by foil soft-X-Ray spectrometer installed on TUMAN-3M and Globus-M2 tokamaks
Authors: Voronin A.V.  , Goryainov V. Yu.  , Zabrodsky V. V.  , Sherstnev E. V.  , Kornev V. A.  , Aruev P. N.  , Kurskiev G. S.  , Zhubr N. A.  , Tukachinsky A. S.
Published: March 2023

Technical solution were presented for a foil spectrometer installed on the Globus-M2 and TUMAN-3M tokamaks for measuring the electron plasma temperature. Measurements have been carried out of the time dependence of the plasma temperature in the central region of tokamaks. Using of integrated photodetectors and unique beryllium foils with a thickness of 14-80 μm made it possible to increase the sensitivity of the spectrometer. An important quality of the foils used were the increased values of strength, plasticity, homogeneity, and the absence of surface and internal defects. The combined use of the spectrometer with Thomson scattering diagnostics made it possible to carry out regular temperature measurements in the Globus-M2 tokamak with a high spatial and temporal resolution. The influence of impurities is estimated on the measurement of the electron temperature of the plasma. Keywords: foil spectrometry, tokamak, plasma, continuum, bremsstrahlung, electron temperature, soft-X-Ray, Si-photodiode.
Formation of a fine-grained Si-=SUB=-1-x-=/SUB=-Ge-=SUB=-x-=/SUB=- thermoelectric by spark plasma sintering
Authors: Dorokhin M. V.  , Boldin M.S.  , Uskova E. A.  , Boryakov A. V.  , Demina P. B.  , Erofeeva I. V.  , Zdoroveyshchev A. V.  , Kotomina V. E.  , Кuzetsov Yu. M.  , Lantsev E. A.  , Popov A. A.  , Trushin V. N.
Published: March 2023

The kinetics of diffusion processes occurring during the formation of polycrystalline Si1-xGex nanostructures (x=0.20, 0.35) by spark plasma sintering in the temperature range 20-1200oC was studied for the first time. A mechanism for the formation of a SiGe solid solution is proposed as a result of a comprehensive study of the microstructure and phase composition of samples with particle sizes from 150 nm to 100 μm, together with the analysis of experimental sintering maps. It is based on the phenomenon of mutual diffusion of Si and Ge atoms that occurs during the entire sintering process. For the selected sintering modes, the grain size of the formed SiGe corresponds to the size of the initial powder particles. Keywords: spark plasma sintering, solid solution SiGe, thermoelectric characteristics, figure of merit ZT.
Investigation of the effect of oxygen partial pressure on the phase composition of copper oxide nanoparticles by vacuum arc synthesis
Authors: Ushakov A. V.  , Karpov I. V.  , Fedorov L. Yu.  , Goncharova E. A.  , Brungardt M. V.  , Дёмин В. Г.
Published: March 2023

Copper oxide nanoparticles were obtained in the plasma of a low-pressure arc discharge. The effect of the partial pressure of oxygen (10-40%) on the physical properties of the deposited nanoparticles has been studied. X-ray diffraction analysis shows that the cubic structure of Cu2O changes to monoclinic CuO with increasing O2 pressure. The results of Raman spectroscopy further confirmed the phase variations of copper-based oxide nanoparticles. X-ray photoelectron spectroscopy confirmed the change in the binding energy in the oxidation state of nanoparticles. The optical band gap of the deposited Cu2O is 2.12 eV, while that of CuO is 1.79-1.82 eV. Keywords: vacuum arc, oxides, nanoparticles, plasma-chemical reactions.
Activation of animal brain neuromediators by interferential transcranial currents
Authors: Katsnelson Y.  , Ilinskiy A.V.  , Shadrin E.B.
Published: March 2023

A method of transcranial electromagnetic stimulation of the mammalian brain is proposed. The method is based on the interference of currents caused by high-frequency orthogonal oscillations of electric fields, which are modulated by low-frequency meander pulses. The effectiveness of the method was confirmed by the results of experiments on stimulating the brain of rats and rabbits. Keywords: electromagnetic stimulation, interference, alpha-rhythms, theta-rhythms, serotonin, beta-endorphins, neuron.
Microwave Schottky diodes based on single GaN nanowires
Authors: Shugurov K.Yu.  , Mozharov A.M.  , Sapunov G.A.  , Fedorov V.V.  , Moiseev E.I.  , Blokhin S.A.  , Kuzmenkov A.G.  , Mukhin I.S.
Published: March 2023

A series of Schottky diodes based on single GaN nanowires has been fabricated. Based on the data of small-signal frequency analysis (parameter S21) of diode structures at various bias voltages, the parameters of the corresponding equivalent electrical circuit were determined. It is shown that the cutoff frequency of the fabricated diodes reaches 27.5 GHz. Keywords: GaN, nanowires, microwave band, Schottky diode.
Joint Effect of a Magnetic Field and a Spin-Polarized Current on Polarity Switching of Magnetic Vortices in a Spin-Transfer Nanooscillator
Authors: Ekomasov E. G.  , Antonov G. I.  , Nazarov V. N.  , Pugach N. G.
Published: March 2023

The combined influence of a spin polarized current and an external magnetic field for switching the polarity of vortices in spin-transfer nanooscillators 400 nm in diameter is studied. A diagram is constructed of the dependence of the magnitude of the spin-polarized current on the magnitude of the magnetic field, which separately switches the polarity of the vortex in the magnetic layers of the spin-transfer nanooscillator. Keywords: magnetic vortice, spin-transfer nanooscillator, magnetic nanodisk.
Temperature control system for the electromagnetic system of the Globus-M2 tokamak
Authors: Varfolomeev V.I.  , Zhenishek E.Yu.  , Lupin A.V.  , Minaev V.B.  , Sakharov N.V.  , Babaritskiy P.A.
Published: March 2023

The temperature control system used for monitoring the thermal regime of operation of the electromagnetic system of the Globus-M2 tokamak is described. The system is a hardware-software complex built on the Arduino platform based on microcontrollers of the AVR family. The developed graphical interface continuously reflects the temperature at the controlled points and signals when it goes beyond the specified range. Automatic saving of measurement results by controlled events is provided. Keywords: tokamak, electromagnetic system, temperature control.
Optimization of the field cathode high voltage training based on field projector data
Authors: Kolosko A. G.  , Popov E. O.  , Filippov S.V.
Published: March 2023

The paper describes a technique for training multi-tip field cathodes with high voltage, which makes it possible to optimize the emission current on the basis of field projector data. The paper presents an algorithm for obtaining and analyzing experimental data, which allows for controlled training of the cathode surface, and also presents the results of the analysis of experimental data obtained for a promising nanocomposite structure of carbon nanotubes in polystyrene. Keywords: Field emission, test of the cold field emission mode, nanocomposite with carbon nanotubes, computerized field emission projector.
Aperture Effect of Normal Hovering Flight in Close Proximity to the Ground
Authors: Zhou X.  , Huang Y.
Published: March 2023

Aerodynamics of a flapping foil at low Reynolds number in close proximity to the ground in aperture effect are studied by numerical simulations based on the normal hovering motion mode. A vortex street is interestingly generated by both ground and aperture effects and the rotation of the foil. The study reveals that the aperture takes a force-reduction effect and a large enough aperture effectively can remove the ground force-enhancement effect produced when the foil is in close proximity to the ground. This paper provides an effective method of optimizing foil-flapping flight design of flying robotics over a porous plane. Keywords: aerodynamics; flapping foil; low Reynolds number; ground effect; aperture effect
Developing a Virtual Reality Educational Tool to Stimulate Emotions for Learning: Focus Group Study
Authors: Lie Silje Stangeland , Røykenes Kari , Sæheim Aleksandra , Groven Karen Synne
Published: March 2023

Background

By watching 360° videos in virtual reality headsets, students may experience being immersed in the portrayed situation. There is a paucity of empirical studies on the application of immersive 360° videos watched in virtual reality headsets for students in health care and social work education and the pedagogical theory guiding the development of such educational tools. This led to our interest in exploring how a virtual reality educational tool involving 360° videos can stimulate emotions and how this can be used as a pedagogical tool in these educational programs.

Objective

The aim of this study was to explore the experiences of faculty members and students regarding a prototype 360° video watched in virtual reality headsets during the development phase of an educational project. We addressed the following research questions: How does the virtual reality prototype stimulate emotions? How can virtual reality be used in higher education for health care and social work students?

Methods

We used a qualitative design and collected data through focus group interviews with project participants. The data were analyzed using qualitative content analysis.

Results

Our analysis identified 2 main themes in participants’ experiences with the virtual reality prototype. The first theme highlights that when participants experienced watching the 360° video in a virtual reality headset, it stimulated their emotions as an authentic professional experience would. The second theme, contextualization of virtual reality, highlights participants’ perceptions of how the virtual reality experience should be incorporated into a safe educational context.

Conclusions

Our findings suggest that 360° videos with human actors who use eye contact with the camera can trigger emotions in the viewer and therefore serve as a pedagogic tool that can create authentic professional experiences for students. The participants expressed the view that the virtual reality educational tool could be used to prepare students for real-life practice in health care and social work. However, they underlined that 360° videos in virtual reality need to be contextualized in educational programs to create a safe environment for learning and to ensure follow-up on the emotions such experiences can trigger in students. Our results highlight the perceived importance of allowing students to reflect on the virtual reality experience in a safe setting and of follow-up by faculty members. In-person follow-up with students can be resource intensive for programs with large numbers of students and makes it challenging to offer repeated training, something that has been identified as one of the benefits of virtual reality.
Adoption of mHealth Technologies by Community Health Workers to Improve the Use of Maternal Health Services in Sub-Saharan Africa: Protocol for a Mixed Method Systematic Review
Authors: Kachimanga Chiyembekezo , Divala Titus H , Ket Johannes C F , Kulinkina Alexandra V , Zaniku Haules R , Murkherjee Joia , Palazuelos Daniel , Abejirinde Ibukun-Oluwa Omolade , Akker Thomas van den
Published: March 2023

Background

Studies have shown that mobile health technologies (mHealth) enhance the use of maternal health services. However, there is limited evidence of the impact of mHealth use by community health workers (CHWs) on the use of maternal health services in sub-Saharan Africa.

Objective

This mixed method systematic review will explore the impact of mHealth use by CHWs on the use of the maternal health continuum of care (antenatal care, intrapartum care, and postnatal care [PNC]), as well as barriers and facilitators of mHealth use by CHWs when supporting maternal health services.

Methods

We will include studies that report the impact of mHealth by CHWs on the use of antenatal care, facility-based births, and PNC visits in sub-Saharan Africa. We will search 6 databases (MEDLINE, CINAHL, Web of Science, Embase, Scopus, and Africa Index Medicus), with additional articles identified from Google Scholar and manual screening of references of the included studies. The included studies will not be limited by language or year of publication. After study selection, 2 independent reviewers will perform title and abstract screening, followed by full-text screening to identify the final papers to be included. Data extraction and risk-of-bias assessment will be performed using Covidence software by 2 independent reviewers. We will use a Mixed Methods Appraisal Tool to perform risk-of-bias assessments on all included studies. Finally, we will perform a narrative synthesis of the outcomes, integrating information about the effect of mHealth on maternal health use and barriers and facilitators of mHealth use. This protocol follows the PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols) guidelines.

Results

In September 2022, we conducted an initial search in the eligible databases. After removing duplicates, we identified 1111 studies that were eligible for the title and abstract screening. We will finalize the full-text assessment for eligibility, data extraction, assessment of methodological quality, and narrative synthesis by June 2023.

Conclusions

This systematic review will present new and up-to-date evidence on the use of mHealth by CHWs along the pregnancy, childbirth, and PNC continuum of care. We anticipate the results will inform program implementation and policy by highlighting the potential impacts of mHealth and presenting contextual factors that should be addressed to ensure the success of the programs.

Trial Registration

PROSPERO CRD42022346364; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=346364

International Registered Report Identifier (IRRID)

DERR1-10.2196/44066
Effects of an online mindfulness-based program for parents of children with attention deficit/hyperactivity disorder: A pilot mixed methods study (Preprint)
Authors: Lo Herman Hay Ming , Lam Jason , Zhang Zoe Ji-wen , Cheung Marsena , Chan Stanley Kam Chung , Wong Elisabeth Wai Yin , Bögels Susan M. , Chui Eric Wing Hong
Published: March 2023

BACKGROUND

Online mindfulness-based programs (MBPs) for parents and families, especially in clinical populations, are limited. Low engagement and substantial dropout are major issues in MBP implementation.

OBJECTIVE

In this pilot study, we examined the effects of an online MBP on parents of children with attention deficit/hyperactivity disorder (ADHD).

METHODS

A mixed methods study was applied to evaluate the effects of the online MBP. Forty-three parents were recruited and randomly assigned to the intervention group and waitlist control group. The MBP lasted for 28 days and consisted of 20 psychoeducation videos, with homework guidance audios, and 4 instructor-led online group meetings. Purposive sampling was then used to recruit parents who had completed the program to share their experiences and suggestions for improving the program in semi-structured online interviews.

RESULTS

The quantitative data showed that the participants of the online MBP perceived a medium to large effect on the reduction of child ADHD symptoms. The participants of the semi-structured interviews reported positive experiences regarding their help-seeking intention and regarding personal changes, such as in emotion regulation and paying quality attention to their children. The interview participants further made suggestions for the improvement of the MBP.

CONCLUSIONS

The online MBP had promising effects. A large-scale randomized controlled trial should be conducted to investigate the effects of the MBP in clinical populations.

CLINICALTRIAL

ClinicalTrials.gov NCT05480423
A Study on Machine Learning And Deep Learning In Medical Imaging Emphasizes MRI: A Systematic Literature Review (Preprint)
Authors: Alqahtani Dr. Saeed
Published: March 2023

BACKGROUND

Due to the fast growth of medical imaging technologies over the last decade, medical practitioners and radiologists find it increasingly difficult to analyze and categorize medical images. Diagnosing, surgery planning, education, and inquiry benefit immensely from the abundance of information in medical images

OBJECTIVE

The objective of our study was to use Machine learning (ML), and deep learning approaches have been applied for medical image analysis; this study focuses on ML for MRI evaluation (MRI). We provide a brief overview of advances in medical image processing and image analysis utilizing machine learning, deep learning, and a few related issues.

METHODS

We provide a brief overview of current advances in medical image processing and image analysis utilizing machine learning, deep learning, and a few related issues. This study paper is limited to two digital databases: (1) Science Direct and (2) Google scholar. This research report reviewed and discussed research publications

RESULTS

Our findings are based on a systematic literature review in which thematic analysis is done, and based on themes, we extract a comprehensive literature review onDL approaches to analyzing brain MRI data have been extensively studied by performing a systematic review. Deep learning (DL)and machine learning techniques based on convolutional neural networks outperform traditional medical image classification, identification, and segmentation methods. various issues, including image localization, segmentation, detection, and classification

CONCLUSIONS

DL approaches to analyzing brain MRI data have been extensively studied by performing a systematic review. Deep learning (DL)and machine learning techniques based on convolutional neural networks outperform traditional medical image classification, identification, and segmentation methods.
“A SWOC Analysis of Online Undergraduate Medical Education and its Impact on Cognitive Outcomes: Cross-Sectional Study” (Preprint)
Authors: Majid Hafsa , Arshad Hajra , Rehman Shanzay , Abidin Zain ul , Siddiqi Hasan Salman , Fatima Sadia , Jafri Lena
Published: March 2023

BACKGROUND

To meet the changing needs of students, teaching methods have evolved over time. Online and technology-augmented teaching is becoming more common in the digital age to increase student engagement. The COVID-19 pandemic has accelerated this shift towards online education, necessitating research into its effects on medical students' academic performance and the modification of medical curricula to meet the needs of future generations.

OBJECTIVE

Based on summative scores, we aimed to compare the academic performance of undergraduate students in online modules compared to traditional face-to-face education and to assess the perceptions of medical students and faculty regarding online education.

METHODS

A cross-sectional study was carried out at Aga Khan University's Medical College in Karachi, Pakistan. Summative exam scores were reviewed before and after the implementation of online education for year II medical students. Medical students and faculty members were also surveyed to understand their perspectives on the challenges and success factors of online education and a SWOC analysis was done.

RESULTS

The mean (SD) scores were 76.93 (7.53) and 75.13 (7.15) before and after the implementation of online education respectively. Online education was welcomed by 66.15% of the student population, whereas face-to-face lectures were favored by 61.54% of the faculty. However, conventional face-to-face Problem-Based Learning (PBL) was favored by both students (55.38%) and faculty (53.58%) over online PBLs. In the future, 52.3% and 76.9% of students and faculty, respectively, supported the notion of blended learning.

CONCLUSIONS

Students in this study were satisfied with online education, although faculty preferred conventional lectures; nonetheless, no difference in cognitive results was seen.
Сімейна поведінкова терапія в лікуванні ожиріння в дітей шкільного віку
Authors: Sorokman T.V. , Sokolnyk S.V. , Popeluk N.O.
Published: March 2023

Актуальність. Ожиріння вражає 27–34 % дітей і вважається головною проблемою громадського здоров’я. Оскільки все більше дітей страждають від надмірної маси тіла, медичним працівникам необхідно шукати ефективні методи профілактики та лікування ожиріння. Мета: оцінити ефективність сімейної поведінкової терапії в лікуванні дітей із ожирінням. Матеріали та методи. Впродовж одного року під спостереженням перебувало 57 дітей віком 7–12 років з ожирінням, які були рандомізовані в дві групи: основну (інтервенційна) — 34 особи (I) та порівняння — 23 особи (II). Діти I групи включені в програму сімейного поведінкового лікування, що полягала в гіпокалорійному харчуванні, контролі за сімейним середовищем та дозованому контрольованому фізичному навантаженні. Ліпідний спектр крові вивчався за рівнем загального холестерину (ЗХС), тригліцеридів (ТГ), холестерину ліпопротеїнів низької (ХС ЛПНЩ) і високої щільності (ХС ЛПВЩ). Результати. У дітей з ожирінням як систолічний (САТ), так і діастолічний арте­ріальний тиск (ДАТ) був підвищений (становив у середньому 125,9 ± 0,9 мм рт.ст. i 66,9 ± 1,2 мм рт.ст. відповідно), також виявлено зростання концентрації ЗХС, ТГ, ХС ЛПНЩ. Через рік після проведення сімейної поведінкової терапії ІМТ у дітей з ожирінням знизився з 26,8 до 25,1 кг/м2, міжгрупові зміни САТ та ДАТ були статистично значущі (I група: до програми САТ становив 124,9 ± 0,8 мм рт.ст., після — 118,9 ± 0,9 мм рт.ст., р < 0,05; ДАТ — 65,7 ± 1,2 мм рт.ст. і 62,1 ± 1,0 мм рт.ст. відповідно, р < 0,05; II група: до програми САТ був 125,1 ± 0,7 мм рт.ст., після — 126,9 ± 0,8 мм рт.ст., р > 0,05; ДАТ — 66,6 ± 1,1 мм рт.ст. і 67,7 ± 1,2 мм рт.ст. відповідно, р > 0,05). Також відбулися достовірні зміни в ліпідному спектрі крові: рівень ЗХС знизився в 0,87 разa, ТГ — у 0,94 разa, при тенденції до зниження ХС ЛПНЩ та підвищення ХС ЛПВЩ. Висновки. Полікомпонентна сімейна поведінкова терапія є ефективною щодо зниження індексу маси тіла дітей з ожирінням. Отримані результати вказують на необхідність застосування запропонованої лікувальної програми в клінічній практиці.