Laboratory Simulation Research Articles

A novel fatigue driving detection method based on whale optimization and Attention-enhanced GRU

Fatigue driving has emerged as the predominant causative factor for road traffic safety accidents. The fatigue driving detection method, derived from laboratory simulation data, faces challenges related to imbalanced data distribution and limited recognition accuracy in practical scenarios. In this study, we introduce a novel approach utilizing a gated recurrent neural network method, employing whale optimization algorithm for fatigue driving identification. Additionally, we incorporate an attention mechanism to enhance identification accuracy. Initially, this study focuses on the driver's operational behavior under authentic vehicular conditions. Subsequently, it employs wavelet energy entropy, scale entropy, and singular entropy analysis to extract the fatigue-related features from the driver's operational behavior. Subsequently, this study adopts the cross-validation recursive feature elimination method to derive the optimal fatigue feature index about operational behavior. To effectively capture long-range dependence relationships, this study employs the gated recurrent unit neural network method. Lastly, an attention mechanism is incorporated in this study to concentrate on pivotal features within the data sequence of driving behavior. It assigns greater weight to crucial information, mitigating information loss caused by the extended temporal sequence. Experimental results obtained from real vehicle data demonstrate that the proposed method achieves an accuracy of 89.84% in third-level fatigue driving detection, with an omission rate of 10.99%. These findings affirm the feasibility of the approach presented in this study.

A Computer Laboratory for the Calculation of the Heat Capacity of a Peptide Unfolding Transition

ABSTRACT We present the implementation of a computer simulation laboratory for the calculation of the heat capacity of the folding-unfolding pseudo phase transition of a polyalanine Ala30 α-helix, using molecular dynamics simulations. Unlike conventional calorimetry experiments, which provide a macroscopic interpretation of the heat capacity, the computer laboratory additionally offers a molecular perspective of the energy exchange processes that lead to the peak of the heat capacity at the phase transition, as well as the statistical mechanical interpretation of the phase transition. The exercise is targeted toward 1st- or 2nd-year students of biophysics in the context of an undergraduate physical chemistry course. We use a graphical web interface to overcome the steep learning barriers associated with command line interactions in commonly used molecular dynamics protocols. The web interface (VIKING) also handles communication with computing hardware in the background, so that students with limited or no programming experience can launch and analyze the simulations easily. A collaboration between the VIKING support team and responsible teachers is required to set up VIKING. We also present a solution in which simulations can be launched on students’ own computers, if some command line knowledge can be expected. The laboratory can also be repurposed for students of various backgrounds (physics, chemistry, biology, or engineering) and scholastic levels (undergraduate or graduate).

From the simulation lab to the operating room: simulation performance predicts intraoperative performance in robotic gastrojejunostomy.

Simulation and video-based assessment (VBA) offer residents the opportunity to develop operative skills while ensuring patient safety. This study aims to determine whether simulation training can predict residents' operative performance, focusing on the gastrojejunal (GJ) anastomosis during robotic pancreatoduodenectomy. Twenty-seven general surgery residents completed simulated robotic GJ drills and subsequently performed GJs in the operating room (OR). Both simulated and intraoperative performances were video recorded and retrospectively assessed by two blinded graders using the Objective Structural Assessment of Technical Skills (OSATS) scale, time to completion, and occurrence of errors. Intraoperative GJ OSATS scores were compared in cases with and without Clinically Relevant Delayed Gastric Emptying (CRDGE). Statistical analysis was performed using Spearman's rho, Chi-square, and Kruskal-Wallis tests. For simulated GJs, the median OSATS score was 29 (IQR 27-33), time to completion was 30min (IQR 27-35), and 11 cases had at least one error. Intraoperative GJs had a median OSATS of 30 (IQR 27-31), time to completion of 41min (IQR 36-51), and errors occurred in nine cases.The OSATS score on the simulated GJs demonstrated a significant positive correlation to the OSATS score on the operative GJs (r = 0.74; p < 0.001) and less time to completion (r = - 0.68; p < 0.001). A shorter simulated GJ completion time significantly correlated with a higher intraoperative OSATS score (r = - 0.52; p < 0.01). Residents with at least one error in the simulated GJs had lower OSATS scores and higher times intraoperatively. Those cases with CRDGE had significantly lower intraoperative OSATS scores than those without CRDGE. Performance on a simulated robotic GJ environment is a robust predictor of OR GJ performance, demonstrating predictive validity. VBA of residents' operative GJ performance is associated with the presentation of CRDGE. Simulation-based training may be crucial to optimizing surgical outcomes before operating on patients.

Stress transfer law in laboratory hydraulic fracturing experiments

During the true triaxial hydraulic fracturing experiments, the compression stress applied to the specimen surface cannot be transferred to the interior immediately, resulting in inconsistency with in-situ stress conditions. To quantitatively analyze the stress transfer process from the surface to the interior of the specimen, an experimental method for monitoring the inside stress was proposed based on Fiber Bragg Grating (FBG) sensing technique, based on which the true triaxial stress loading experiments were conducted on a concrete-like specimen of 30 cm × 30 cm × 30 cm. The results show that the stresses inside the specimen require a certain loading time to reach the uniform state. The loading time required for stress transfer from the surface to the interior of the specimen decreases with the increase of compression stresses. The stress transfer process in rock materials is determined by creep. The closure of microcracks results in stress redistribution inside the specimen during creep. Moreover, a 3-D Burgers model is modified to describe the stress transfer process. Finally, the stress transfer phenomenon during hydraulic fracturing was verified by coal fracturing experiments. This study can help to understand the stress transfer mechanism, providing guidance for standardizing the laboratory simulation of in-situ stress.

Student nurses' utilisation of self-directed simulation learning at a University in Gauteng.

Self-directed simulation learning (SSL) is a globally accepted teaching and learning strategy wherein student nurses take the initiative in diagnosing their learning needs, formulate learning goals, identify resources for learning, and implement relevant strategies in response to their learning needs. This autonomous learning strategy will assist student nurses in taking ownership of their learning. Consequently, student nurses exit the training programme to become lifelong learners, safe and competent professional nurses. This study aimed to explore and describe the experiences of student nurses' utilisation of SSL at a University in Gauteng and to make recommendation(s) to enhance the use of SSL. A qualitative, exploratory, descriptive, and contextual research design was used to uncover the student nurses' experiences with the use of SSL at a University. Nineteen participants were purposively sampled. Data collection was conducted through focus group interviews. Tesch's method of data analysis was used to analyse, organise and interpret data. Theme: student nurses experience time constraints, which hinder their utilisation of SSL. Subthemes: (1) a compacted academic timetable, and (2) limited access to the clinical simulation laboratory for self-directed learning. Time constraints hinder the utilisation of SSL, and this challenge threatens the acquisition of clinical skills and knowledge during the training of student nurses.Contribution:Evidence-based recommendations to enhance the utilisation of SSL at a University.

Design and systematic evaluation of an under-canopy robotic spray system for row crops

Despite having made much improvement in sensing, automation, and control, the current broadcast spraying system has several drawbacks, such as uneven coverage, excessive chemical use, and deviation from recommended dosage. Typically, farmers use large self-propelled sprayers to spray the entire field without knowledge of spatial pest severity, potentially resulting in an unintentional application. However, application errors and the extent of chemical use can be optimized by utilizing an intelligent site-specific decision-based sprayer to control pests more efficiently. Hence, the initial project goal was to design a robotic liquid application system for row crops (e.g., sorghum and corn) and validate sprayer system performance. The critical design considerations for the spray application system were modularity; the ability to be mounted on an autonomous platform to go within 76.2-cm spaced crops; spray on either side of the crop row using spray booms; onboard hardware and software for control and data acquisition; and record as-applied data. A system with desired design requirements was built and individual sub-systems were tested under simulated lab scenarios to quantify the response time and accuracy of the spray system. The results showed that the sprayer could maintain an average system pressure within ±5% of the target under different duty cycles for each of the six nozzles. At 40% duty cycle, the nozzle pressure settling time at an error margin of ±5% from the mean was 13 ms, 20 ms, and 19 ms, for one, three, and six nozzles, respectively. Also, no substantial pressure difference was observed between nozzles installed at different heights in two different booms. Therefore, this application system could be a viable solution for autonomous platforms to site-specifically apply pesticides only on critically infested plants, has the potential to decrease the overall input costs on chemicals and reduce the negative environmental impacts.

The Melting Behavior of Hydrogen Direct Reduced Iron in Molten Steel and Slag: An Integrated Computational and Experimental Study

Direct reduced iron (DRI) and hot briquetted iron (HBI) are essential feedstocks for tramp element control in the electric arc furnace (EAF). Due to greenhouse gas (GHG) concerns related to CO2 emissions, hydrogen as a substitute for natural gas and a reductant in DRI production is being widely explored to reduce GHG emissions in ironmaking. This study examines the melting behavior of hydrogen DRI (H-DRI) pellets in the EAF containing low-carbon (0.1 wt.%) molten steel and molten slag. A computational heat transfer model was developed to predict the melting behavior of H-DRI pellets. To validate the model, a set of experimental laboratory simulations was conducted by immersing H-DRI in a molten steel bath and slag. The temperature history at the center of the pellet during melting and the shell thickness at different melting stages were utilized to validate the model. The simulation results agree with the experimental measurements of steel balls and H-DRI in different metallic molten steel and slag baths.

In-Person Versus Online Training in Simulations of Helping Babies Breathe: A Randomized Controlled Trial.

Birth asphyxia is a leading cause of neonatal deaths, but simple interventions may prevent it. The Helping Babies Breathe (HBB) course has significantly reduced neonatal mortality ratesin lower and middle-income countries (LMICs) by training healthcare providers (i.e. midwives and nurses) on the essential skills of bag-and-mask ventilation and postnatal care. Although several studies have supported the efficacy of virtual learning in other medical education programs, there is still a lack of knowledge regarding a virtual approach to HBB. This study aims to compare the effectiveness of online versus in-person learning of the HBB course among medical and nursing students. The study is a two-arm parallel randomized non-inferiority controlled trial, that includes medical and nursing students. Participants were randomly assigned to either online or in-person debriefing during the hands-on simulations of HBB. They attended a pre-recorded lecture before being assigned to one of three instructors for the simulation lab. Participants completed a seven-point anonymous Likert-based questionnaire and a standardized Debriefing Assessment for Simulation in Healthcare Student Version (DASH-SV) Short Form. The primary outcome was the Objective Structured Clinical Exam (OSCE) grade. The trial is listed on ClinicalTrials.gov with the registration number NCT05257499. 47 participants completed the study, with similar baseline characteristics in each arm (gender, age, and class). The participants in both arms reported high levels of satisfaction and confidence, with no significant difference between the two arms. The DASH score over 7 was also similar in the online arm(6.27±0.26) compared to the in-person arm (6.55±0.13) (p=0.07). The mean OSCE scorein the online arm (45.8±5.2) was comparable to the mean OSCE score in the in-person arm (41.3±5.0) (p=0.22). Both online and in-person participants failed the OSCE. The survey responses conveyed that online simulation training is comparable to in-person simulation for the HBB course. Both online and in-person participants failed the OSCE most likely because they needed more training on HBB. This could be due to the fact that the material is too new to the students who needed more practice to pass the OSCE. Further research is needed to confirm these results and explore the long-term impact of online neonatal resuscitation training.

Behind the scenes: Uncovering the downsides of skill and simulation laboratories

Behind the scenes: Uncovering the downsides of skill and simulation laboratories

Research and application on in-situ monitoring of strata movement in submarine cold seeps area based on three-dimensional MEMS sensor network

Accurate monitoring of strata movement is crucial for understanding the geomorphological evolution of the cold seeps. However, the complex environments and inherent challenges of deep-sea operations present significant obstacles for existing observation methods. In this paper, we present a strata movement monitoring system based on a three-dimensional micro-electromechanical system (MEMS) sensor network that includes multiple short and long sensor arrays. The movement vector is reconstructed using triaxial-acceleration and cubic Hermite interpolation. In laboratory simulations with vertical and horizontal displacement of 250 mm and 100 mm, respectively, the root mean square error of the reconstruction model is 3.74 mm. Two sensor arrays were deployed and operated for 4 days in cold seeps in South China Sea, and the observed displacement showed micro-tremors, and the displacement ranges in the x- and y- directions were (−0.4 mm, 0.18 mm) and (−0.43 mm, 0.19 mm), respectively. These results affirm the feasibility of the proposed system.

Simulation Training in Vascular and Endovascular Surgery: A Nationwide Survey Among Surgeon Educators and Trainees in France

Vascular surgical training is evolving towards simulation-based methods to enhance skill development, ensure patient safety, and adapt to changing regulations. This study aims to investigate the utilization of simulation training among vascular surgeons in France, amidst ongoing shifts in teaching approaches and educational reforms. A national survey assessed the experiences and perceptions of vascular surgery professionals regarding simulation training. Participation was open to self-reported health professionals specialized (or specializing) in vascular surgery, including interns or fellows. Participants were recruited through various channels, and data were collected via a questionnaire covering participant characteristics, simulation experiences, and perceptions. Seventy-six participants, predominantly male (74%) took part in the survey. While 58% reported access to simulation laboratories, only 17% had organized simulation sessions 1-3 times a year, and 5% had sessions more than 10 times annually. High fidelity simulators were available in 57% of institutions, while low fidelity simulators were available in 50%. Regarding funding, 20% received financial assistance for training, predominantly from industry (18%). One-third of the participants experienced 9 or more sessions (34%), lasting between 1 and 2hours (34%), 30% expressed satisfaction with access to simulation, while 33% were dissatisfied with communication of simulation training opportunities. Despite recognizing the benefits of simulation training, its integration into vascular surgery education in France remains incomplete. Challenges such as limited access and communication barriers hinder widespread adoption. Collaborative efforts are needed to ensure uniformity and enhance the effectiveness of simulation training in vascular surgery education.

Generation and emission mechanism of polycyclic aromatic hydrocarbon (PAHs) during the coking process in Shanxi, China

Although coking process is the important source of polycyclic aromatic hydrocarbons (PAHs) in the environment, the generation and emission of PAHs during this process is unclear. It is crucial to clarify the formation mechanism of PAHs in coal pyrolysis during the coking process for effectively identifying and controlling the emission of these organic pollutants. In this study, the combination of laboratory simulation and field sampling was used to analyze the mechanism of PAHs formation and emission in coking process. The release of PAHs from the pyrolysis process of coal blends used in coking plants was 1778.20 ± 111.95 μg · g−1, which was much higher than the content of free PAHs in raw coal (76.50 ± 12.46 μg · g−1). 3-ring PAHs were the most abundant components of free PAHs and pyrolysis-generated PAHs. PAH formation during pyrolysis of coal blends was primarily attributed to the cracking of the macromolecular structure of coal, with minimal influence of free PAHs in blended coal. The emission of PAHs from coal-charging was higher (62.93 ± 17.75 μg · m−3) than that from pushing of coke (11.79 ± 1.91 μg · m−3·, PC) and combustion of coke oven gas (5.53 ± 1.20 μg · m−3, CG), and was mainly related to free PAHs in coal. In contrast, the characteristics of PAHs in the flue gas of PC and CG were similar to those from blended coal pyrolysis. PAHs in fugitive emission from coke oven were primarily affected by flue gas leakage and were mainly related to coal pyrolysis and free PAHs in blended coal.

Properties of biochars derived from different straw at 500℃ pyrolytic temperature: Implications for their use to improving acidic soil water retention

Climate change cause extreme weather effects with temperature increases and drops in humidity, such as drought and heatwaves, which will lead to more evaporation in arid and semi-arid lands. The application of biochar made from crop straw without burning to farmland can effectively improve the water retention capacity of soil. A testing program has been carried out in a climate simulation laboratory to study the effects of different straw biochars on the cracking and evaporation of soils due to drying. Biochar from wheat straw (WS), corn straw (CS) and rice straw (RS) is produced at a pyrolysis temperature of 500℃. Thermogravimetric analysis and elemental analysis are carried out to obtain the properties of the biochar. Five percent of WS, CS and RS biochar by weight is added to acidic soil. Digital camera and digital image processing technology are used to analyze the crack morphology of the samples during evaporation. The results indicate that the RS biochar has the highest ash content (32.5 %), CS biochar has the highest content of volatile solid (25.36 %) and WS biochar has the highest content of fixed carbon (55.38 %). Biochar can effectively improve the water retention capacity of soil. The final water contents of the WS, CS and RS biochar soil samples are 132.3 %, 101.0 %, and 20.7 % respectively higher than that of the soil without biochar. Moreover, biochar can effectively reduce the degree of soil cracking. The addition of WS, CS and RS biochar can reduce soil cracking by 9.21 %, 16.57 %, and 7.46 %, respectively. WS contains more total cellulose than CS and RS, so WS biochar is the best choice to improve soil water retention ability. Therefore, biochar technology helps to optimize soil water retention while avoiding environmental pollution from straw burning.

Assessment order and faking behavior

AbstractPersonality testing is a critical component of organizational assessment and selection processes. Despite nearly a century of research recognizing faking as a concern in personality assessment, the impact of order effects on faking has not been thoroughly examined. This study investigates whether the sequence of administering personality and cognitive ability measures affects the extent of faking. Previous research suggests administering personality measures early in the assessment process to mitigate adverse impact; however, models of faking behavior and signaling theory imply that test order could influence faking. In two simulated applicant laboratory studies (Study 1 N = 172, Study 2 N = 174), participants were randomly assigned to complete personality measures either before or after cognitive ability tests. Results indicate that participants who completed personality assessments first exhibited significantly higher levels of faking compared to those who took cognitive ability tests first. These findings suggest that the order of test administration influences faking, potentially due to the expenditure of cognitive resources during cognitive ability assessments. To enhance the integrity of selection procedures, administrators should consider the sequence of test administration to mitigate faking and improve the accuracy of personality assessments. This study also underscores the need for continued exploration of contextual factors influencing faking behavior. Future research should investigate the mechanisms driving these order effects and develop strategies to reduce faking in personality assessments.

Epistemic fluency in virtual laboratories as flipped classroom’s innovative learning delivery

PurposeDesign an innovative Flipped classroom’s Delivery through virtual laboratory.Design/methodology/approachThe fundamental framework of the present investigation is a Participatory Action Research (PAR) design. By merging the impetus of “action.” with the inclusiveness of “participation,” PAR establishes a “network” for collaborative teaching or research. PAR is pertinent to our research because it facilitates the participation of infrastructures and individuals in formulating a critical community. This community encourages critical self-reflection, promotes accountability, redistributes authority, and cultivates confidence in research. PAR fosters constructive transformation in educational environments by utilizing participants' combined insights and experiences to establish a structure for substantive dialogue and proactive measures.FindingsAs virtual laboratories are becoming essential in 21st-century science education, we found groundbreaking evidence that can support our novel approach to enhance the quality and equity in education. Our results show that virtual labs engage scientific goals and practices, develop scientific literacy, foster scientific inquiry and problem-solving, and promote metacognition. The effects of the virtual laboratory can develop high self-efficacy and positive attitudes among students. It improves students' laboratory performance, which we noted from laboratory activities, simulations, and long exam results.Originality/valueThe study offers groundbreaking account to depict epistemic fluency aided by virtual laboratory.

Sensitivity analysis of hydraulic erosion and calibration of the erosion coefficient

Hydraulic erosion may pose a threat to the safety and sustainability of geo-related infrastructure, yet quantifying the intricate process of hydraulic erosion still poses a significant scientific and technical challenge. One important step in meeting this challenge is the formulation of a hydraulic erosion model with the erosion coefficient as a central controlling parameter. Calibration of the erosion coefficient (or rate) remains one of the main obstacles to improving predictive modelling, particularly in scenarios lacking long-term laboratory test data. In this study, sensitivity analysis of the key erosion indicators on the parameters controlling hydraulic erosion is conducted. A novel calibration method for the erosion coefficient is presented based on sensitivity analysis. After validating against simulation results and laboratory test findings, the proposed calibration method is applied to a hypothetical long-term hydraulic erosion case. The results show that the maximum hydraulic erosion time is sensitive to all considered parameters (erosion coefficient, initial fraction of fluidized solid particle, initial porosity and maximum porosity), while the erosion curve shape is only sensitive to the initial porosity and the maximum porosity. The validation by existing simulation results shows that the proposed calibration method is robust and internally consistent. The validation by experimental results indicates that the proposed calibration method also has high external validity. Finally, the proposed calibration method is applied to hypothetical long-term erosion in a grouted area. The results show that the hydraulic erosion effect in the grouted area becomes increasingly severe over time. This study contributes toward a more efficient calibration of the erosion coefficient, especially for scenarios in the absence of testing porosity evolution data. The research outcome provides a theoretical foundation for the safety assessment and sustainability analysis of geotechnical structures that are subject to hydraulic erosion.

Appropriate characterization of reservoir properties and investigation of their effect on microbial enhanced oil recovery through simulated laboratory studies

Appropriate characterization of reservoir properties and investigation of the effect of these properties on microbial metabolism and oil recovery under simulated reservoir conditions can aid in development of a sustainable microbial enhanced oil recovery (MEOR) process. Our present study has unveiled the promising potential of the hyperthermophilic archaeon, identified as Thermococcus petroboostus sp. nov. 101C5, to positively influence the microenvironment within simulated oil reservoirs, by producing significant amounts of metabolites, such as biosurfactants, biopolymers, biomass, acids, solvents, gases. These MEOR desired metabolites were found to cause a series of desirable changes in the physicochemical properties of crude oil and reservoir rocks, thereby enhancing oil recovery. Furthermore, our study demonstrated that the microbial activity of 101C5 led to the mobilization of crude oil, consequently resulting in enhanced production rates and increased efficiency in simulated sand pack trials. 101C5 exhibited considerable potential as a versatile microorganism for MEOR applications across diverse reservoir conditions, mediating significant light as well as heavy oil recovery from Berea/carbonaceous nature of rock bearing intergranular/vugular/fracture porosity at extreme reservoir conditions characterized by high temperature (80–101 °C) and high pressure (700–1300 psi). Core flood study, which truly mimicked the reservoir conditions demonstrated 29.5% incremental oil recovery by 101C5 action from Berea sandstone at 900 psi and 96 °C, underscoring the potential of strain 101C5 for application in the depleted high temperature oil wells.

Standard setting OSCE: A comparison of arbitrary and Hofstee methods in a low stake OSCE

Objectives: To compare the cut scores and pass/fail rates achieved by arbitrary 60% method and Hofstee method in an undergraduate year 4 end semester objective structured clinical examination (OSCE) and check the possibility of using Hofstee method of standard setting in future exams. Method: 102 medical students of year 4 underwent a 10 station OSCE exam conducted in a state of art simulation lab in 3 cycles. The cut scores were calculated using arbitrary method aiming at 60% of task achievement and by Hofstee method. The student’s obtained scores were compared for cut scores and pass rates for individual stations and the entire exam. Results: The arbitrary and Hofstee methods of standard setting leads to different cut scores. For the individual stations it was 60% vs 65-70% and for the overall score it was 60% vs 70%. The percentage of students failing the exam is 13.7% based on arbitrary scores and is 29.4% when Hofstee cut score is applied. Conclusions: The two methods lead to different cut scores and students’ failure rates. Overall, Hofstee method is more appropriate for assessing competencies in an OSCE exam in medical schools as it leads to calculation of cut scores based on the difficulty level of the station/exam and the examiners expected level of performance by the students. Keywords: Objective Structured Clinical Examination, Standard Setting, Hofstee Method, Arbitrary Method

Effect of nitrogen oxides and sulfur oxides to triphenyl phosphate degradation and cytotoxicity on surface of different transition metal salts

Nitrogen oxides and sulfur oxides, as the dominant toxic gases in the atmosphere, can induce severe human health problems under the composite pollutant conditions. Currently the effect of nitrogen or sulfur oxides in atmospheric environment to the degradation and cytotoxicity of triphenyl phosphate (TPhP) on atmospheric particle surfaces still remain poorly understood. Hence, laboratory simulation methods were used in this study to investigate the effect and related mechanism. First, particle samples were prepared with the TPhP coated on MnSO4, CuSO4, FeSO4 and Fe2(SO4)3 surface. The results showed that, when nitrogen or sulfur oxides were present, more significant TPhP degradation on all samples can be observed under both light and dark conditions. The results proved nitrogen oxides and sulfur oxides were the vital influence factors to the degradation of TPhP, which mainly promoted the OH generation in the polluted atmosphere. The mechanism study indicated that diphenyl hydrogen phosphate (DPhP) and OH-DPhP were two main stable degradation products. These degradation products originated from the phenoxy bond cleavage and hydroxylation of TPhP caused by hydroxyl radicals. In addition, no TPhP related organosulfates (OSs) or organic nitrates (ON) formation were observed. Regarding the cytotoxicity, all the particles can induce more significant cellular injury and apoptosis of A549 cells, which may be relevant to the adsorbed nitrogen oxides or sulfur oxides on particles surfaces. The superfluous reactive oxygen species (ROS) generation was the possible reason of cytotoxicity. This research can supply a comprehensive understanding of the promoting effect of nitrogen and sulfur oxides to TPhP degradation and the composite cytotoxicity of atmospheric particles.

Increasing pitch count is associated with increasing elbow flexion angle at ball release in youth baseball pitchers

Baseball is one of the most popular sports among youth athletes in the United States, and among these players, pitchers are at a particularly high risk of sustaining an injury. Overuse of the arm from repetitive pitching is a common mechanism for injury. Despite the attention that overuse injury has received, little is known regarding the mechanism that leads to elbow injury. This study aims to determine the effect of increasing pitch count on elbow flexion at ball release in a youth pitching cohort. The authors hypothesize that elbow flexion would increase as pitch count increases. Study subjects included volunteers from youth baseball players from local teams and public advertisements. Retroreflective markers attached to bony landmarks were placed on the players according to International Shoulder Group recommendations. Pitchers threw an indoor simulated game. Three-dimensional marker trajectories were collected using a 12-camera optical motion capture system, and ball velocity was captured using a radar gun. Voluntary maximal isometric strength of the internal and external rotators was evaluated before and after pitching. Paired 2-tailed t tests were performed to determine if a significant change occurred between the fresh and fatigued sets. Twelve adolescent male pitchers were recruited. Eleven of 12 pitchers completed the prescribed 6 sets of 15 pitches, culminating in a 90-pitch simulated game. The ball speed in the second set was found to be the highest in all pitchers and was considered the "peak set" (P=.021), whereas ball speed was the slowest in the sixth set of pitches and was therefore considered the "fatigue set" (P=.001). There was a moderate but statistically significant inverse correlation between elbow flexion at ball release and maximum internal rotation velocity (P=.005). Elbow flexion at ball release was also significantly positively correlated with shoulder abduction at ball release (P=.004). Elbow flexion at ball release was not significantly correlated with ball velocity (P=.108). In a simulated game laboratory setting, increasing pitch count was associated with increasing elbow flexion angle at ball release in youth baseball pitchers. These findings demonstrate that pitching with fatigue may cause biomechanical changes that have been associated with increased rates of elbow injury in the adult throwing population. Further investigation on the association between elbow flexion angle and elbow injury in the youth baseball population is needed.