bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Drop Jump Training from Different Heights and Weight Training on Vertical Jump and Maximum Strength Performance in Female Volleyball Players
Authors: Sotiropoulos Konstantinos , Smilios Ilias , Barzouka Karolina , Christou Marios , Bogdanis Gregory , Douda Helen , Tokmakidis Savvas P. 
Published: July 2022

Abstract
Sotiropoulos, K, Smilios, I, Barzouka, K, Christou, M, Bogdanis, G, Douda, H, and Tokmakidis, SP. Effects of drop jump training from different heights and weight training on vertical jump, maximum strength and change of direction performance in female volleyball players. J Strength Cond Res 37(2): 423–431, 2023—This study compared the effects of drop jump (DJ) training from different drop heights and weight training on vertical jump and maximum strength performance. Fifty-five female volleyball players (age: 23.8 ± 4.3 years) were randomly and equally allocated to a control group (volleyball training, CG); a volleyball and weight training group (WG); and 3 volleyball, weight, and drop jump training groups. One group performed DJ training from the optimal drop height, i.e., the height that elicited the highest ratio of jump height to contact time (OG), a second group from a drop height 25% higher than the optimal (HG), and a third group from a drop height 25% lower than the optimal (LG). Drop jump and weight training were performed 1–2 times per week, for 8 weeks for a total of 13 sessions. After training, vertical jump performance improved by 3.6–17.4% (p < 0.05; effect size [ES]: 1.03–1.23) in the OG and the HG compared with the LG, WG, and CG (p < 0.05; ES: 0.03–0.58). Drop jump height from drop heights 20–70 cm increased by 10.0–20.2% (p < 0.05; ES: 0.59–1.13) for the OG and the HG, while reactive strength index increased (p < 0.05; ES: 0.74–1.40) by 19.6–33.9% only in the HG compared with the CG. Half-squat maximum strength was increased in all experimental groups by 17.4–19% compared with the CG (p < 0.05) with no differences (p > 0.05) observed among them. The use of the optimal height or a moderately higher drop height by 25% for DJ training, combined with weight training, seems to be the most beneficial option to improve vertical jump and reactive strength index in female volleyball players.
Does External Load Reflect Acute Neuromuscular Fatigue and Rating of Perceived Exertion in Elite Young Soccer Players?
Authors: Martínez-Serrano Antonio , Freitas Tomás T. , Franquesa Xavi , Enrich Edgar , Mallol Milos , Alcaraz Pedro E. 
Published: July 2022

Abstract
Martínez-Serrano, A, Freitas, TT, Franquesa, X, Enrich, E, Mallol, M, and Alcaraz, PE. Does external load reflect acute neuromuscular fatigue and rating of perceived exertion in elite young soccer players? J Strength Cond Res 37(3): e1–e7, 2023—This study aimed to analyze the acute and residual effects of increased high-speed running (HSR) demands during an in-season training microcycle in young elite soccer players on localized neuromuscular fatigue (NMF) of the knee extensors (KE), posterior chain muscles, and rating of perceived exertion (RPE). Thirty-four elite young soccer players (age = 17.1 ± 0.8 years) were assessed in 2 consecutive days at different time points (baseline, POST-activation gym-based session, POST–small-sided game [SSG], POST-training 1 [TR1], POST-6H, POST-24H, POST-preventive gym-based session, and POST-training 2 [TR2]). Neuromuscular fatigue of the KE and posterior chain muscles was measured with a maximum voluntary isometric contraction (MVIC). External (total distance, number of accelerations or decelerations, and HSR distance) and internal (RPE) load was assessed during the SSG, TR1, and TR2 sessions. Players were divided through a median split, into “HIGH” or “LOW” group according to the training demands. The alpha level was set at p ≤ 0.05. A 2-way mixed effects model ANOVA showed a significant decreased in 90:20 MVIC after TR1 in the “HIGH” HSR group (p = 0.037; effect size [ES] = 0.45). No significant differences in RPE were found after TR1 (p = 0.637; ES = 0.58) and TR2 (p = 0.109; ES = 0.62) when comparing the “HIGH” HSR group with the “LOW” HSR group. Assessing player's force production capabilities can be an effective strategy to detect NMF when HSR demands are acutely increased. Special caution should be taken when prescribing the training load of the training session based solely on RPE, as NMF might be present.
Cardiovascular risk in Danish transgender persons: a matched historical cohort study
Authors: Glintborg Dorte , Rubin Katrine Hass , Petersen Tanja Gram , Lidegaard Øjvind , T’Sjoen Guy , Hilden Malene , Andersen Marianne Skovsager 
Published: July 2022

Background
Cardiovascular risk could be increased in transgender persons, but the mechanism is undetermined.

Aim
The aim of this study was to assess the risk of cardiovascular outcomes in Danish transgender persons compared to controls.

Methods
The study design was a historical register-based cohort study in Danish transgenders and age-matched controls. The main outcome measure was cardiovascular diagnosis (any CVD) including medicine prescriptions for CVD during 2000–2018. The transgender cohort (n = 2671) included persons with International Classification of Diseases-10 diagnosis code of ‘gender identity disorder’ (n = 1583) and persons with legal sex change (n = 1088), 1270 were assigned female at birth (AFAB) and 1401 were assigned male at birth (AMAB). Controls (n = 26 710) were matched by age (n = 5 controls of same and n  = 5 controls of other birth sex) of the respective transgender.

Results
The median (interquartile range) age at study inclusion was 22 (18; 29) years for AFAB and 26 (21; 39) years for AMAB. The mean (s.d.) follow-up time was 4.5 (4.2) years for AFAB and 5.7 (4.8) years for AMAB. The hazard ratio (HR) for any CVD was significantly higher in transgenders vs controls of same and other birth sex, with highest adjusted HR in transgenders AFAB vs control men: 2.20 (95% CI: 1.64;2.95), P < 0.001. Gender-affirming hormone treatment (GAHT) explained part of elevated risk of CVD in transgenders AFAB, whereas GAHT did not contribute to the elevated risk of CVD in transgenders AMAB.

Conclusions
The risk of cardiovascular diagnosis was increased in transgenders. The mechanism should be further investigated.
EXPERIMENTAL FINDING OF YOUNG’S MODULUS OF A WELD BOX GIRDER MADE OF STEEL 09Г2С
Authors: Ryagin S. 
Published: July 2022

Purpose. Experimental finding of Young’s modulus values of the specimen of steel 09Г2С with weld longitudinal arrangement and of the basic metal, which is used for box girder manufacturing, by means of non-electrical strain measurement under various loads. Comparison of the received results among themselves and with data of references.
Methods of research. Experiment, strain measurement, least-squares technique.
Results. Several metal strips of steel 09Г2С arranged crosswisely have been welded for making of a specimen. The specimen of steel 09Г2С with weld longitudinal arrangement and rectangular cross-section has been produced of the received detail by milling with cooling. Tests have been executed on calibrated equipment for finding of Young’s modulus values of the weld and of the basic metal. Strains have been measured by Huggenberger tensometer during experiment. Experimental results have been processed by least-squares technique. The received results have been compared among themselves and with data of references. It has been found out, that Young’s modulus values of the basic metal on all references are comparable, but differ one from another. Young’s modulus values of the weld differ essentially. Weld Young’s modulus is a little bigger than basic metal Young’s modulus according to experimental data of other author. Weld Young’s modulus is a little smaller than basic metal Young’s modulus according to the received experimental data. This difference can be explained, in particular, by different ways of production of specimens for finding of weld Young’s modulus.
Scientific novelty. Young’s modulus values of the specimen of steel 09Г2С with weld longitudinal arrangement has been experimentally found by means of mechanical strain measurement under various loads and with result processing by least-squares technique.
Practical value. Experimentally found Young’s modulus values of the weld of the basic metal are necessary at physical and mathematical modelling of a stress state of a box girders of steel 09Г2С.
PERFORMANCE CHARACTERISTICS OF NICKEL-CONTAINING STEEL STRUCTURES DURING MECHANIZED WELDING-SURFACING WITH MODIFIED (DOSED) ELECTRODE WIRE FEEDING
Authors: Lebedev V. , Zuck G. G. , Brykov M. 
Published: July 2022

Purpose. To study and analyze in a comparative order the influence of factors of the controlled pulse process of electrode wire supply on some basic mechanical characteristics of seams and welded rollers in the processes of welding and surfacing of nickel-containing steels.
Methods of research. The study the mechanical characteristics of seams and welded rollers was carried out using modern laboratory equipment and appropriate techniques. This made it possible to determine how the pulse feed parameters affect the strength characteristics of the weld and near the weld zone over the entire cross-sectional area of the weld or weld layer. Detailed characteristics of feed pulses were determined using a welding process analyzer to obtain oscillograms of power parameters of arc combustion with their analysis, including determining the stability of the arc process for different types of pulses. Important for the improvement of welding results is the controlled nature of the electrode metal transfer synchronous with the pulsed movement of the electrode. It is noted that the energy consumption of the arc process during the pulse supply of the electrode wire with an indication of its reduction compared to traditional welding.
Experimental work was performed using a special electrode wire, which is usually used for welding and surfacing of nickel-containing steels. These processes were carried out in a protective environment of CO2 in automatic mode.
Results. Due to the fact that the strength characteristics of the weld are among the most important, attention is paid to their definition and analysis. The strength characteristics depend on many parameters, in particular the thermal characteristics of the process, the structure of the weld metal, the presence of non-metallic inclusions and so on. All these factors were studied with the help of appropriate instruments, and on the basis of numerous comparative photos of microstructures on sections of the cross section. The analysis of the sections revealed the types of microstructures obtained, the presence of inclusions and more. It is determined, in particular, that the structure of weld metal in pulsed electrode wire welding differs significantly from the structure of traditional welding in reducing inclusions, finer grains, etc., which improves the mechanical properties of the weld and seam area.
Scientific novelty. Based on a series of experimental studies, the use of pulse algorithms for the movement of the electrode wire with certain parameters in automatic mode for welding and surfacing of nickel-containing steels to improve the mechanical properties of seams and welded rollers.
Practical value. It is determined that the method of pulse welding of electrode wire to the controlled variant, including nickel-containing steels is effective and can be widely used in industry using specially designed equipment that provides a suitable process with stronger characteristics.
IMPROVEMENT IN DURABILITY OF WELDED DRUMS COMPRESSOR ROTORS BY TREATMENT IN FLUDIZED BED OF ABRASIVE MATERIAL
Authors: Kachan О. , Ulanov S. 
Published: July 2022

Purpose. Improvement in durability of welded drums of compressor rotors of the gas turbine engines by treatment in fluidized bed of abrasive material.
Methods of research. The investigations were carried out on the welded drums of rotors of high pressure compressor (HPC) of the D-36 aero engine. The drums were treated in the fluidized bed of abrasive material of the АПС-600 installation without the nozzles and with the use of special air-blast nozzles.
Test specimens for checking durability were cut of HPC stages 1 and 4 discs after carrying out various machining processes.
Durability testing of test specimens cut of HPC stage 4 disc was carried out at the УМЭ-1 ТМ machine at temperature Т = 400 °С.
Durability testing of test specimens cut of HPC stage 1 disc was carried out at the ЭДЦ-20 machine at temperature Т = 20 °С.
Results. It was found that averaged cyclic life of the test specimens made of titanium alloy ВТ-9, treated in the fluidized bed of abrasive material being a part of the drum with the use of air-blast nozzles, is 2.2 times higher than the averaged cyclic life of the test specimens treated in the fluidized bed of abrasive material without the use of air-blast nozzles at temperature Т = 400 °С.
When treating the drum of the HPC rotor in the fluidized bed of abrasive material without the use of air-blast nozzle, better treatment of the bottom of the slot and corners of its end faces is ensured.
Low-temperature annealing of the drum at temperature Т = 550 °С is preferable than at Т = 750 °С, since cyclic life of the test specimens annealed at Т = 550 °С is somewhat higher.
Annealing at Т = 750 °С removes completely strengthening effect obtained by treatment in the fluidized bed of abrasive material.
Successive treatment of the disc as a part of the drum in the fluidized bed restores its durability to the initial state.
Scientific novelty. It was demonstrated that treatment of the welded drums of the compressor rotors in the fluidized bed of abrasive material with the use of special air-blast nozzles improves the quality of treatment and cyclic life if compared to the treatment without air-blast nozzles.
Annealing temperature for the compressor rotor drum, which ensures high average cyclic life, was established.
Practical value. There were offered technological procedure and modes of treatment of the welded drums of the HPC of the D-36 aero engine in the fluidized bed of abrasive material with the use of special air-blast nozzles, ensuring durability 2.2 times higher than without the use of the air-blast nozzles.
THE STUDY OF THE PECULIARITIES OF THE MECHANIZED ELECTRIC ARC CLADDING WITH PERIODIC VARIATION OF THE MODES OF THE PROCESS
Authors: Lebedev V. , Tishchenko V. , Brykov M. 
Published: July 2022

Purpose. Research of the influence of modulation of arc processes on characteristics of clad metal with revealing the dependences of chemical composition and geometrical dimensions of the clad metal on the modulation parameters, as well as the development of mathematical models of these dependences with the purpose of predicting the results of modulation to improve the quality of deposited layers.
Methods of research. Well-known methods of surfacing metal research were used:
spectral analysis of metal composition, metallographic analysis of the obtained samples of cross-sections of the cladding rolls. Special computerized programs were used to measure geometric dimensions of the roll. Methods of regression analysis were used in order to obtain generalized mathematical models of dependencies of chemical elements and geometrical dimensions on modulation parameters.
Results. In the process of research with electric-arc cladding of electrode flux-cored self-shielded wire, generalized results of dependences of carbon, chromium and boron content, width, amplification and penetration of cross-sectional area on the frequency and modulation duty cycle of electric-arc process parameters were obtained. Method of mathematical description of modulation effect on chemical composition and shape of the weld bead was developed.
Scientific novelty. It was suggested to carry out estimation of the results by applying mathematical models when carrying out the electric arc process with periodic change of power parameters of current surfacing due to controlling the electric drive of the electrode wire feeding mechanism and also with change of voltage when controlling the output voltage of the welding current source.
Practical value. A set of studies concerning the effects of modulation of power parameters of the welding process using an original development of the modulator allows, based on relatively simple systems of automatic and mechanized equipmen makes it possible, to obtain a controlled process of influence on the characteristics of the fused metal with their improvement for the implementation in industrial production.
Epidemiological assessment of long-term maternal and failed maternal mortality
Authors: Padrul M. M. , Isaeva N. V. , Cherkasova E. V. , Berseneva S. N. 
Published: July 2022

Objective. To conduct epidemiological studies of the long-term dynamics of maternal mortality (MM) and failed maternal mortality, development of trends and territorial distribution.
Materials and methods. The data of official statistics on maternal mortality calculated for
100 000 live births and a long-term dynamics of unrealized maternal mortality according to the data of the Ministry of Healthcare of PK "Unified Information System of Healthcare of Perm Krai" are presented. The number of cases of complicated pregnancy, childbirth and the postpartum period with the formation of multiple organ dysfunction or insufficiency requiring intensive therapy, blood transfusion and emergency surgical interventions was calculated. The epidemiological descriptive and evaluative method was used when performing the studies. The long-term dynamics of MM was calculated, the rectilinear epidemic trend for the function of the parabola y1 = a + bx and the curvilinear tendency for the function of the parabola y2 = a + bx + c2, its upper and lower confidence bounds (Me 0.95) were determined. The rate of growth and increment were investigated and the research cyclical fluctuations were determined.
Results. The maximum level of maternal losses (ML) in Perm Krai established in 2003 was 44.2 per 100 thousand live births. The minimum figure in 2015 was 5.2 per 100 thousand live births. The average long-term indicator of MM is 19.3. A feature of the long-term dynamics of the studied period was a steady decline in MM with an average annual rate of 5.7 %. Cyclical fluctuations were initially regular in nature, and subsequently had a lengthened rhythm of 13 years. Failed maternal mortality in Perm Krai had a pronounced downward trend; the decrease rate was 518.9 %. The annual loss rate was 69.8 %.
Conclusions. The long-term dynamics of MM in Perm Krai was characterized by an average degree of intensity, an epidemic tendency to decrease, the presence of cyclical fluctuations, the formation of internal causes testifying to the possible activation of maternal losses. The long-term dynamics of failed maternal mortality had a pronounced downward trend.
Electrocardiographic and cardiobiochemical reactions in patients with closed chest injury
Authors: Vakhrushev D. S. 
Published: July 2022

Objective. To study the electrophysiological and clinicobiochemical characteristics of cardiovascular system in closed injury of the chest.
Materials and methods. There were examined 114 persons diagnosed the closed chest injury, who were admitted to the Thoracic Unit of City Clinical Hospital №9 in Izhevsk. The causes and mechanisms of injuries, the data of clinical and functional methods of investigations of cardiovascular system, the data of case histories and previous preventive examinations were analyzed. The comparison group involved 50 practically healthy men.
Results. The mean age of the persons in the main group and the comparison group was 45.9 12.8 years and 44.7 11.5 years, respectively. The prevailing causes of injury were the following: road accident 17 persons (14.9 %), fall from a height (higher than ones own height) 32 persons (28.0 %), fall from a height of ones own height 37 persons (32.5 %). The increased values of the markers of myocardium damages and inflammatory reaction as well as the changes in electrocardiographic parameters were established among the examined persons.
Conclusions. The closed chest injury occurs mainly in the able-bodied population that, of course, is an actual factor for a possible unfavorable labour prognosis. When analyzing the ECG parameters and cardiometabolic characteristics, there were detected the deviations earlier absent in these patients and in patients of the comparison group, which showed the myocardial damage.
Finite-Difference Simulation for Infrasound Generated by Finite-Extent Ground Motions
Authors: Kim Keehoon , Bowman Daniel C. , Fee David 
Published: July 2022

Abstract
Underground explosions can produce infrasound in the atmosphere, and the wavefield characteristics are often governed by the ground surface motions. Finite-difference methods are popular for infrasound simulation as their generality and robustness allow for complex atmospheric structures and surface topography. A simple point-source approximation is often used because infrasound wavelengths tend to be large relative to the source dimensions. However, this assumption may not be able to capture the complexity of explosion-induced ground motions if the surface area is not compact, and appropriate source models must be incorporated into the finite-difference simulations for accurate infrasound prediction. In this study, we develop a point source representation of the complex ground motions for infrasound sources. Instead of a single point source, we use a series of point sources distributed over the source area. These distributed point sources can be equivalent to air volume changes produced by the ground motions in the atmosphere. We apply the distributed point-source method to a series of buried chemical explosions conducted during the Source Physics Experiment Phase I. Epicentral ground-motion measurements during the experiments provide a way to calculate accurate distributed point sources. We validate and evaluate the accuracy of distributed point source approach for infrasound simulations by direct comparison with acoustic observations in the field experiment.
Comparison of microanatomy of ascending aorta and pulmonary trunk with age: A cross-sectional study
Authors: Alex Reba Babu , Kalyanikuttyamma Lathi Kumari , Sudhakaran Manju 
Published: July 2022

Cardiovascular disease (CVD) accounts for the leading cause of mortality worldwide and it has a strong association with age. Aging brings about structural and functional changes in vessels, culminating in CVD. This study aims at determining and comparing the structural age changes in the two great vessels of heart, ascending aorta (AA) and pulmonary trunk (PT).Human ascending aorta and pulmonary trunk samples were obtained during autopsy from 55 individuals of different age group. After processing, they were stained with eosin haematoxylin and special stains to identify connective tissue fibres and smooth muscle cells. Thickness of each tunic of the vessel wall, full wall thickness, quantity of smooth muscle cells and severity of fragmentation of elastic fibres were detected.In all age groups, PT was thinner than AA. Average full wall thickness of AA was greatest in the sixth decade of life while that of PT in the fourth decade. Elastic fibres were long, straight and arranged in a lamellar pattern in tunica media of both the vessels in fetal life. They underwent fragmentation from first decade of life in PT and from third decade in AA. Grade5 fragmentation was noticed only in PT. Degeneration of smooth muscle cells occurred in both the vessels with age, but was very little in PT.Both the great vessels showed degenerative changes with advancing age, but after the first decade of life, the changes were very less in PT when compared to AA.