Reaction Speed Research Articles

The basics of theory and methods of mastering the game of table tennis in the classroom physical education of students

How to master the game of table tennis in physical education classes. At the beginning of your classes, you need to get acquainted with how the racket interacts with the ball, "feel" the racket and the ball, learn to control its flight in different ways, master the basic striking movements, master the orientation of the torso, arms, legs and racket in space, etc.
 Purpose: to analyze the essence and significance of the stages of table tennis training in physical education classes: (special physical training; technical training, techniques; tactical training; psychological training).It is important to learn how to hold the racket correctly and perform various exercises with the racket and ball off the table, as this will help you master the technique of the game faster. In this case, it is recommended to use the following exercises: moving around the court, holding the ball on the racket and watching the grip, rolling the ball on the racket from one edge to the other or in a circle, repeatedly hitting the ball with different sides of the racket from the bottom up or alternately with one and the other side of the racket, strive to keep the ball from falling to the ground as long as possible (should be performed both in place and in motion); driving the ball with the racket, hitting the floor (dribbling), in the player's stance on the spot or in motion; to give the ball rotation with both sides of the racket in different directions: from the body to the right or left; to hit the ball with a racket to different heights in turn - high bounce, low bounce; crouching and standing up, to hit the ball: hit - crouch, hit again - stand up.
 When playing on the table, you need to pay attention to the correctness of your movements. The basics of the technique can be properly mastered and consolidated only with repeated repetition of technical elements in a game environment on the table, and the prerequisites for this are practicing the technique with the help of imitation exercises. In the future, a lot depends on coordination of movements, musculoskeletal sensitivity, attentiveness, reaction speed, as well as the level of development of such qualities as endurance, perseverance, dedication and efficiency.

Effects of ignition location on CH4/air explosion characteristic in a spherical bomb

To build methane anti-explosion storage equipment, the influence of the ignition location on the CH4/air explosion in a spherical equipment was investigated. A two-step CH4/air reaction mechanism was developed and it considered the effect of heat transfer on the explosion. The effect of methane explosion pressure on heat loss was studied. The results show that the maximum explosion pressure of central ignition is 0.72 MPa under the heat loss simulation. The peak pressure of the upper and lower end-wall explosion is about 79.2 % and 83.3 % of the central ignition explosion, respectively, and the experimental results verifies the simulation results. Therefore, the reason for the highest peak pressure of central ignition methane explosion is that the reaction speed of central ignition methane explosion is the fastest, and the heat loss is the lowest. The difference in peak pressure between the upper and lower wall surfaces is due to the buoyancy effect accelerates the reaction rate of the lower end-wall ignition. In the simulation time range, the heat radiation at different ignition locations accounts for more than 70 % of the total heat loss, and radiation heat transfer plays a leading role in the total heat loss.

Efficient DNA walker guided by ordered cruciform-shaped DNA track for ultrasensitive and rapid electrochemical detection of lead ion

The rational design of DNA tracks is an effective pathway to guide the autonomous movement and high-efficiency recognition in DNA walkers, showing outstanding advantages for the cascade signal amplification of electrochemical biosensors. However, the uncontrolled distance between two adjacent tracks on the electrode could increase the risk of derailment and interruption of the reaction. Hence, a novel four-way balanced cruciform-shaped DNA track (C-DNT) was designed as a structured pathway to improve the effectiveness and stability of the reaction in DNA walkers. In this work, two kinds of cruciform-shaped DNA were interconnected as a robust structure that could avoid the invalid movement of the designed DNA walker on the electrode. When hairpin H2 was introduced onto the electrode, the strand displacement reaction (SDR) effectively triggered movements of the DNA walker along the cruciform-shaped track while leaving ferrocene (Fc) on the electrode, leading to a significant enhancement of the electrochemical signal. This design enabled the walker to move in an excellent organized and controllable manner, thus enhancing the reaction speed and walking efficiency. Compared to other walkers moving on random tracks, the reaction time of the C-DNT-based DNA walker could be reduced to 20 min. Lead ion (Pb2+) was used as a model target to evaluate the analytical performance of this biosensor, which exhibited a low detection limit of 0.033 pM along with a wide detection ranging from 0.1 pM to 500 nM. This strategy presented a novel concept for designing a high-performance DNA walker-based sensing platform for the detection of contaminants.

Promoting effect of low concentration strontium on photosynthetic performance of Chinese cabbage seedlings: Combined leaf characteristics, photosynthetic carbon assimilation and chlorophyll fluorescence

Low concentration strontium (LC-Sr) can promote the growth of plants. In order to explore its promoting mechanism from the aspect of photosynthesis, the leaf characteristics, CO2 assimilation and chlorophyll (Chl) a fluorescence kinetics were investigated with hydroponically LC-Sr-treated Chinese cabbage seedlings. After a 28-d treatment to SrCl2 at different concentrations (0.1, 0.2, 0.5, and 1.0 mmol L−1), we observed an increase in the specific leaf weight (SLW) of Chinese cabbage compared with the control group. Notably, as the strontium concentration increased, a more pronounced improvement trend in the contents of Chl and protein in the leaves was observed, contributing to the enhancement of photosynthesis. However, the statistical differences in Pn among various LC-Sr treatments were not significant. Nevertheless, the leaf starch content exhibited a significant increase after LC-Sr treatments. Additionally, Chl a fluorescence transient has been used as a sensitive indicator of the promotional effect of LC-Sr on photosynthesis. The results of fluorescence parameters showed that LC-Sr treatments accelerated the light reaction speed of leaves (Tfm, dV/dto, dVG/dto), improved the energy utilization efficiency of photosystem (PSI and PSII) (ETo/CSo, ψET,ψRE, δRo, φRo), and ultimately enhanced the photosynthetic performance of leaves (PIabs, SFIabs, DFabs). The increased RCs/CSo and Sm contributed to the enhancement of the light reaction activity of strontium-treated leaves. The LC-Sr treatments had no interference with the calcium absorption, and notably enhanced the photosynthetic capacity of Chinese cabbage, shedding light on potential benefits of LC-Sr for crop cultivation.

Mechanism of improving anaerobic fermentation performance of kitchen waste pretreated by ionizing irradiation-part 1: rice.

Ionizing irradiation, as a new pretreatment method for the anaerobic fermentation of organic pollutants, is featured with fast reaction speed, good treatment effect, no need to add any chemical reagents, and no secondary pollution. This study explores the mechanism of improving anaerobic fermentation performance of rice samples pretreated by cobalt-60 gamma irradiation through the influence on fermentation substrate, acidogenic phase and methanogenic phase. The results reveal that the soluble chemical oxygen demand of the irradiated rice sample at an absorbed dose of 9.6 kGy increases by 12.4 times due to the dissolution of small molecules of fat-soluble organic matter. The yield of biogas in the acidogenic phase increases by 22.2% with a slight increase in hydrogen gas content. The yield of biogas and methane gas content in the methanogenic phase increases by 27.3% and 15%, respectively. Microbial genome analysis, performed with MiSeq high-throughput sequencing and metagenomic methods, suggests the microbial abundance and metabolic functions in the anaerobic fermentation process change significantly as a result of the pretreatment by gamma irradiation.

Viscosity-dependent control of protein synthesis and degradation

It has been proposed that the concentration of proteins in the cytoplasm maximizes the speed of important biochemical reactions. Here we have used Xenopus egg extracts, which can be diluted or concentrated to yield a range of cytoplasmic protein concentrations, to test the effect of cytoplasmic concentration on mRNA translation and protein degradation. We find that protein synthesis rates are maximal in ~1x cytoplasm, whereas protein degradation continues to rise to a higher optimal concentration of ~1.8x. We show that this difference in optima can be attributed to a greater sensitivity of translation to cytoplasmic viscosity. The different concentration optima could produce a negative feedback homeostatic system, where increasing the cytoplasmic protein concentration above the 1x physiological level increases the viscosity of the cytoplasm, which selectively inhibits translation and drives the system back toward the 1x set point.

Impact of exercise training and diet therapy on the physical fitness, quality of life, and immune response of people living with HIV/AIDS: a randomized controlled trial

BackgroundExercise and dietary nutrition are considered crucial in human immunodeficiency virus (HIV)/ acquired immunodeficiency syndrome (AIDS) treatment protocols and people living with HIV/AIDS (PLWHA) rehabilitation care. However, there is no well-studied research evaluating the effects of combined interventions on the fitness and immune systems of PLWHA. Therefore, this study aimed to analyze the effects of exercise and dietary intervention on physical fitness, quality of life and immune response in PLWHA.MethodsThis was an experimental study, with a sample of 25 male PLWHA divided into two groups: the intervention group (IG: 12 participants) and the control group (CG: 13 participants). All participants have not had any exercise habits and nutritional supplements in the past six months. The participants in the IG completed 45 min of exercise (60-80% HRmax) 4 times per week for 4 weeks. The exercise was in the form of brisk walking or running. They were also given a nutritional dietary supplement 3 times a day for 4 weeks. The 13 individuals in the CG continued their normal daily life (physical activity and diet). The following parameters were evaluated before and after the intervention: body composition, physical fitness, immune response, quality of life (QoL), stress, dietary behavior, dietary habits, exercise motivation, and physical self-efficacy.ResultsThe significant changes were observed in burnout of stress variables and physical efficiency index (PEI) of physical fitness in the IG (p =.023). Moreover, in the saliva samples, sal-T levels significantly increased only after the intervention in the IG (p =.012). Additionally, regarding the analysis of the interaction (group × time), there was a significant improvement in the reaction speed (p =.001) and grip strength (left: p =.002, right: p =.030) and a significant difference in physical satisfaction in QoL (p =.001), stress burnout (p =.043), self-confidence in physical efficacy (p =.045), external display (p =.008), and fulfillment (p =.047) in exercise motivation. Moreover, the significant effect of the intervention on emotional eating in dietary behavior was shown in the comparison of the IG before and after intervention (p =.001) and in the comparison of the IG group with the CG after the experiment (p =.013). However, there was no significant effect of time or interaction between the condition and time on body composition.ConclusionsIn conclusion, exercise training and diet therapy caused changes in physical fitness and Sal-T levels, which had positive effects on the health promotion of PLWHA.

FITNESS TOOLS IN THE REHABILITATION ACTIVITIES OF BASKETBALL PLAYERS AT THE TRAINING STAGE OF PREPARATION

Relevance. Basketball is a traumatic sport, and it is second only to martial arts (such as boxing and taekwondo) in terms of the number of injuries. As a rule, external factors of sports injuries are not always controllable, but internal factors canbe minimized even at the initial stages of training with the help of specially organized recovery programs. At the same time, it is necessary to take into account both the morphological and functional features of adolescents, as well as physi-ological processes, as well as psychological characteristics that can provoke sports injuries. The purpose of the study: to determine the eff ectiveness of the experimental methodology of the integrated use of fi tness tools in the reco very and prevention of injuries of female basketball players aged 13–15 years. Materials and research methods. The study in-volved 2 groups of basketball players aged 13–15 years. In the experimental group, fi tness tools were used in recovery activities, the control group was engaged in a traditional program. At the beginning and at the end of the study, the re-spondents recorded the peculiarities of the course of mental processes and technical profi ciency. Results. The introduc-tion of an experimental program of injury recovery and prevention based on fi tness technologies for basketball players aged 13–15 years allowed us to achieve the following changes at the fi nal stage of the study: in the experimental group, the indicators of technical profi ciency are statistically signifi cantly higher (the number of shots in motion, the number of hits in the “free throws” standard, the time of the shuttle run with the ball). In addition, diff erences were found in the rate of mental processes (the number of errors in the “Proof-reading test”, the speed of reaction to a moving object in the “Ruler” test, the results of the tapping test of the left hand, the coeffi cient of functional asymmetry). Conclusions. A signifi cant number of relationships between the indicators of technical profi ciency and mental processes allow us to conclude that the formation of “functional supports”, which are a sign of eff ective recovery and helps to reduce the prob-ability of injury from internal factors.

Dynamic behavior of enzyme kinetics cooperative chemical reactions

This article uses computational mathematics to investigate the dynamics of cooperative occurrences in chemical reactions inside living organisms. We study the dynamics of complex systems using mathematical models based on ordinary differential equations, paying special attention to chemical equilibrium and reaction speed. Explanations of cooperation, non-cooperation, and positive cooperation are presented in our study. We analyze the stabilities of equilibrium points by a systematic analysis that makes use of the Jacobian matrix and the threshold parameter R0. We next extend our investigation to evaluate global stability and the probability of the model. Variations in k3 have a notable effect on substrate concentration probabilities, indicating that it plays an important role in reaction kinetics. Reducing k3 highlights the substrate's critical contribution to the system by extending its presence in the concentration. We find that different results were obtained for cooperative behavior: higher reaction rates at different binding sites are correlated with positive cooperativity, while slower reactions are induced by negative cooperativity. The Adams–Bashforth method is used to show numerical and graphical solutions with the help of MATLAB. Tables and graphs are used to further explain the effects of the parameters. This study underlines how well ordinary differential equations may represent the complicated system dynamics found in chemical reactions. It also provides elusive insights into cooperative occurrences, which develops our understanding of the phenomenon and serves as a foundation for future research.

Prospects and challenges of sensor materials: A comprehensive review

Sensor materials have become more important in several industries as they facilitate the development of advanced sensing technologies in the modern day. These materials, specifically engineered to transform physical, chemical, or biological stimuli into quantifiable signals, play a crucial role in gathering vital data for controlling, monitoring, and making informed decisions. It is essential to comprehend the obstacles and prospects linked to sensor materials, given the escalating demand for sensor systems that are both efficient and versatile. The sensing qualities of a material refer to its capacity to detect and quantify alterations in its surroundings. These properties encompass a range of approaches, including optical, chemical, piezoelectric, capacitive, and resistive interactions. Although these materials are utilized in various industries such as transportation, medicine, agriculture, industrial operations, and environmental monitoring, persistent issues are still related to improved reaction speed, selectivity, and sensitivity. Nevertheless, the outlook for sensor materials seems optimistic, as current research and advancements are anticipated to result in materials that exhibit enhanced performance, durability, and energy economy. Developing nanomaterials and sophisticated production processes facilitates the potential for creating highly selective and sensitive sensors with new functionalities. This advancement contributes to the growth of the Internet of Things (IoT) and its applications in massive data collection, leading to enhanced automation and decision-making capabilities. This review article examines the recent advancements, applications, and research in sensor materials while also discussing the obstacles they encounter and the potential opportunities that enable them to significantly impact multiple industries and society.

INFLUENCE OF THE MENSTRUAL CYCLE ON THE PHYSICAL PERFORMANCE OF YOUNG FEMALE STUDENTS AT THE INSTITUT NATIONAL SUPERIEUR DE L EDUCATION POPULAIRE ET DU SPORT (INSEPS) IN DAKAR

Objective:Toevaluatetheinfluenceofthemenstrualcycleonthephysicalqualitiesofsome INSEPS students. Method: 15 female students participated in our study. Each subject performed the verticalrelaxation, reaction speed, abdominal endurance and back endurance tests on the third day ofmenstruationand the third oneaftercessation of bleeding. Results: On average, the subjects had better vertical expansion after menstruation (45.13cm) than during menstruation (43.33 cm), with no significant difference (p=0.57). In terms ofreactionspeed,thegirlsperformedbetteronaverageduringmenstruationthanafter(111versus147), with no significant difference (p=0.06). The best average performance in abdominalendurance was achieved during menstruation (390.6 repetitions versus 367.73 repetitions) butthis difference was statistically insignificant (p=0.56). In back endurance, the best averageperformanceforgirlswasachievedaftermenstruation(342.67repetitionsversus337.53repetitions).Thedifferencewas statisticallyinsignificant (p=0.92). Conclusion:Thisstudy showsthatthe menstrualcycle doesnothave a significantinfluence on the vertical relaxation, reaction speed, abdominal endurance and back enduranceofthe INSEPS students inour sample.

Evaluation of Lower Extremity and Core Strength in Young Female and Male Volleyball Players

Volleyball is an anaerobic team sport that involves various complex movements and requires adequate body position sense. Therefore, volleyball players' most important physical characteristics are balance, agility, endurance, reaction speed, explosive strength, and quick strength. This study aimed to evaluate the relationship between core strength and functional performance of lower extremities in male and female volleyball players. A total of 19 (11 female, eight male) volleyball players aged 16-20 years (11 female, eight male) who were students of Ondokuz Mayıs University Yaşar Doğu Faculty of Sports Sciences participated in the study voluntarily. The inclusion criteria were determined as athletes with at least three years of active sports history and regular training. Height, weight, and Body Mass Index measurements were taken at the first visit. Then, shuttle test, plank test, push-up, single hop for distance (SH), triple hop for distance (TH), crossover triple hop for distance (CH), medial side triple hop for distance (MSTH), and medial rotation ( ) with hop for distance (MRH) and Y Balance Test were performed with randomized practice cards. When the push-up, sit-up, and plank tests were compared between men and women, a significant difference was found in the shuttle parameter (p 0.05). When the athletes' Single Leg Hop test parameters were evaluated, there was no significant difference, only in SH between the sides in men. At the same time, there was no significant difference only in medial rotation ( ) with hop in women (p 0.05). While there was a significant difference in triple hop for distance, crossover triple hop for distance, medial side triple hop for distance (MSTH) and medial rotation ( ) with hop between the parties in men, a statistically significant difference was found in single hop for distance, triple hop for distance, crossover triple hop for distance, medial side triple hop for distance parameters in women (p 0.05). When single-leg hop Tests LSIs were compared between male and female groups, no statistically significant difference was found in all parameters (p 0.05). When the findings of our study were examined, it was determined that although there was a significant difference in Single Leg Hop test parameters between dominant and non-dominant sides in the groups, the LSI values seen in male and female groups were between normal values, and there was no limb asymmetry. However, there was no difference between genders in LSIs, and similar results were found for men and women. In the core strength tests, while similar results were seen between genders in push-up and plank parameters, the significant difference in the shuttle test revealed that men had better core strength than women.

Effects of six-week stroboscopic training program on visuomotor reaction speed in goal-directed movements in young volleyball players: a study focusing on agility performance

BackgroundIn team sports, deficits in visuomotor reaction speed are considered a significant and modifiable risk factor that can lead to decreased performance and an increased risk of injuries. Thus, identifying effective methods to enhance visuomotor abilities is crucial. The main objective of this research was to investigate the impact of a six-week stroboscopic intervention on visuomotor reaction speed in goal-directed specific movements based on agility among young volleyball players. Additionally, the study aimed to explore the impact of saccade dynamics on visuomotor reaction speed performance throughout the experiment.MethodsThere were 50 athletes (26 males and 24 females) with an average age of 16.5 years (± 0.6) who participated in this study. Over a six-week training period, athletes performed volleyball-specific training either wearing stroboscopic glasses (intervention) or under normal visual conditions (control). Prior to and after the training period, the agility tests based on change-of-direction speed (CODS) and reactive agility (RA) were used to identify visuomotor reaction speed performance. To measure agility performance a five-repetition shuttle run to gates was conducted. The REAC-INDEX, which represents visuomotor reaction speed, was analyzed as the resulting difference between the CODS test and the RA test. To elicit saccadic dynamics, a laboratory visual search task was performed.ResultsA significant GROUP×TIME interaction was observed for the REAC-INDEX (p = 0.012, ηp2 = 0.13). ANCOVA analyses revealed significant GROUP differences, indicating improved post-training REAC-INDEX results (p = 0.004, d = 0.87), regardless of gender. Training-induced modulations in saccade acceleration did not reach significance, but a significant relationship was observed between changes in saccade acceleration and changes in the REAC-INDEX (r = -0.281, p = 0.048), indicating that higher performance gains following training were associated with a stronger increase in saccade acceleration.ConclusionsThis study demonstrates that stroboscopic training effectively enhances visuomotor reaction speed in goal-directed movements based on agility. Furthermore, visuomotor reaction speed gains could potentially be mediated by saccade dynamics. These findings provide valuable insights into the effectiveness of stroboscopic eyewear for training sport-specific visuomotor skills among young volleyball players.

Characteristics of specific training in elite handball players specialized in goalkeeper position

Background and Study Aim. Elite handball goalkeepers undergo intensive training for reflexes and advanced techniques. They develop mental toughness to handle the pressure and responsibility at key moments of the game. Thus, they protect the goal of the team. This study aims to investigate and highlight the specific training characteristics of elite handball players specialized in the goalkeeper position. Material and Methods. The best 4 goalkeepers specialized in elite handball in Romania, aged between 22 and 33 years, were selected. Specific motor tests were used: Test 1 - Jumps 15 seconds; Test 2 – Reaction speed to visual stimulus; Test 3 – Execution speed. Technical tests were used: Test specific to goalkeeper, Triangle moving, The Ten Jump, Ball throwing, Standing long jump, Passes to a fixed point; The Cooper test. To improve specific training, there were applied strategies for training optimization which include stretching for mobility, segmental muscle strength, goalkeeping specific exercises and plyometrics. The nonparametric Spearman’s correlation coefficient was used to evaluate the relationship between technical training and motor skills parameters. The statistical significance level was set at p<0.05. Results. The performance of elite handball players specializing in goalkeeper position highlighted significant improvements in the Jumps 15 sec test. Contact time decreased by 0.13 seconds while the jump height increased by 0.55 cm, showing improved efficiency and power. In the Reaction speed to visual stimulus test, waiting time and reaction time decreased considerably, while the foot rising height increased. In the right and left leg Execution speed test, the differences observed reveal individual adaptations. The overall time is low in the right foot and there is a significant increase in the left foot. The nonparametric Spearman correlation analysis showed the relationship between the indices of technical fitness tests and the strength and speed motor skills. During Test 1 - Jumps 15 sec - 49 correlations were identified, of which 5.36% were statistically significant, highlighting strong connections between certain parameters. The analysis of Test 2 showed 56 correlations, but the lack of statistical significance reveals the absence of connections between the technical tests and the parameters of reaction speed manifestation. Regarding Test 3, a number of 28 correlations were identified. The lack of statistical significance suggests the absence of significant correlations between the technical tests and the execution speed. Conclusions. The performances of elite handball goalkeepers show significant improvements in motor and technical skills, highlighting the effectiveness of specific training and its adaptability. The progress in jumping and reaction speed indicates essential improvements for goalkeeping success, emphasizing the necessity for personalized and holistic training.

Assessing Different PCR Master Mixes for Ultrarapid DNA Amplification: Important Analytical Parameters.

The basic principles of ultrafast plasmonic PCR have been promulgated in the scientific and technological literature for over a decade. Yet, its everyday diagnostic utility remains unvalidated in pre-clinical and clinical settings. Although the impressive speed of plasmonic PCR reaction is well-documented, implementing this process into a device form compatible with routine diagnostic tasks has been challenging. Here, we show that combining careful system engineering and process control with innovative and specific PCR biochemistry makes it possible to routinely achieve a sensitive and robust "10 min" PCR assay in a compact and lightweight system. The critical analytical parameters of PCR reactions are discussed in the current instrument setting.

Properties of Molybdenum Disulfide and Preparation Method

Behind the development of integrated circuits to the current brilliant era is the contribution of Moore's Law, which has guided the development prospects of the industry for a long time. But as transistors continue to shrink in size and thickness, silicon itself approaches its own physical limits and Moore's Law no longer applies. Therefore, scientists are eager to solve this puzzle by introducing new materials, including two-dimensional materials. Molybdenum disulfide has attracted much attention because of its special properties, and the preparation method needs to be studied deeply for large-scale use of molybdenum disulfide. There are many factors that affect the synthesis of single layer molybdenum disulfide, such as the amount of reaction source, air pressure, substrate, reaction temperature of two sources, source heating rate, holding time, relative position between molybdenum source and sulfur source substrate, gas flow, etc. In short, these reaction conditions are summarized, which mainly affect the concentration and reaction speed of sulfur source and molybdenum source in the reaction substrate position. In this paper, the effects of CVD on the quality of single layer disulfide were summarized and its development trend was prospected.

Research on preparation of high activity and durable carbon-supported platinum catalyst for methanol electro-oxidation by a facile continuous microwave pipeline method

In methanol oxidation reaction (MOR), it is crucial for the catalyst that Pt particles uniformly cover the surface of the carrier and the Pt surface active sites can effectively remove the binding with CO. This article develops a simple and effective continuous microwave technology. Carbon loaded nano platinum was synthesized by rapidly and uniformly heating a ethylene glycol mixture containing carbon black (CB) H2PtCl6 using microwave radiation, with a Pt content of 49.5%. The experimental results indicate that platinum particles are uniformly loaded onto the carbon surface, with uniform shape and size, and an average particle size of 3.02 nm. And the Pt/C catalyst prepared by continuous microwave technology showed enhanced electrocatalytic activity (peak current density of 76.95 mA/cm2) in MOR after heating at appropriate temperature in N2 atmosphere, which exceeded the commercial catalyst TKK (47.07 mA/cm2) by 63.6%. And the catalyst's resistance to CO toxicity and durability; Higher than commercial Pt/C catalysts. Compared with traditional methods, continuous microwave technology exhibits higher energy utilization efficiency and faster reaction speed in the catalyst preparation process. This technology also has the ability to achieve continuous preparation, which is one of the effective technological approaches to achieve large-scale catalysts production.

Photoluminescence Studies of DoF Effect on the Photopolymerization Reaction of a GelMA‐Based Monomers for Tissue Engineering

AbstractIn the present work methacrylated gelatin (GelMA) is obtained at different methacrylate anhydride concentrations (5.8% V/V and 10% V/V), different reaction times (1 h and 3 h), and under pH control. A ninhydrin test and NMR are used to determine the degree of functionalization (DoF) of the samples showing that pH controlling produces better functionalization degrees than an increase in methacrylate anhydride concentration or longer reaction times. The photopolymerization process of GelMA samples is studied by time‐resolved photoluminescence at different photoinitiator (PI) concentrations: 0.5%w/V, 1%w/V, and 2%w/V. An increase in PI concentration and DoF produces changes in the crosslink. The 2%w/V concentration produces a higher reaction speed in the first 10 minutes and requires longer times to end the reaction. No significant differences were found in the use of smaller concentrations.This article is protected by copyright. All rights reserved

Tumor microenvironment sensitization via dual-catalysis of carbon-based nanoenzyme for enhanced photodynamic therapy

Photodynamic therapy (PDT) is limited in tumor therapy due to the mature antioxidant barrier of tumor microenvironment (TME) and phototoxicity/easy-degradation characteristics of photosensitizers. Therefore, we prepared Cu2+-doped hollow carbon nanoparticles (CHC) to protect the loaded photosensitizers and sensitize TME by glutathione-depletion and peroxidase (POD)-like activity for enhanced PDT. CHC significantly increased the maximum speed of POD-like reaction (Vm) of 8.4 times. By coating with hyaluronic acid (HA), the active sites on CHC were temporarily masked with low catalytic property, and restored in response to the overexpressed hyaluronidase in TME. Meanwhile, due to the excellent photothermal conversion efficiency (32.5 %) and hollow structure of CHC, the loaded photosensitizers were well protected from sunlight activation-induced unwanted phototoxicity and rapid degradation under the near-infrared light irradiation. In-vivo anti-tumor experiments demonstrated that the combination of photothermal-photodynamic effect achieved the best anti-tumor effect (tumor inhibition rate at 87.8 %) compared with any monotherapy. In addition, the combination of photothermal and photodynamic effect could efficiently suppress the cell migration, manifesting the reduced number of lung metastasized nodules by 74 %. This work provides an integrated platform for photosensitizers protection and TME sensitization for enhanced PDT.

The Effect Of Vitamin B Plus With Special Exercises On Some Physiological Variables, Skill and Physical Abilities In Volleyball


 The importance of the research lies in using B vitamin with special exercises as well as identifying their effect on some physiological, skill and physical variables in volleyball. The problem of the research was the lack of using vitamins for athletes in addition to weakness in training programs. The research aimed at identifying the effect of using vitamin B with special exercises on physiological variables ( Hb – Pcv, systolic and diastolic blood pressure and pulse), physical abilities (legs and arms explosive power – power defined by speed, speed of reaction and agility), and fundamental skills (underarm and overhead pass, blocking and spike).The researcher hypothesized statistical difference between pre and posttests in both groups in physiological, skill and physical abilities in volleyball. In addition to that she hypothesized significant differences in favor of the posttests for the experimental group. The results showed a positive effect for using vitamin B with special exercises on physiological, skill and physical variables in volleyball. Finally the researcher recommended using different types of vitamins with other spcial exercises to develop these abilities.