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Background: The purpose of this report is to provide insight and details regarding the development and implementation of an injury and illness surveillance (IIS) system for the United States Olympic and Paralympic Committee (USOPC). Methods: The development and deployment of the IIS employed a multiphase approach. First, researchers determined variables to include in the IIS using the recommendations from the 2020 IOC consensus statement for reporting sport epidemiological data. Second, the hosting and deployment platforms were comprehensively evaluated for their suitability, ease of use, flexibility, and backend data structure (for both capture and aggregation). Third, focus groups consisting of the Sports Medicine department leadership and clinicians piloted the IIS system and revisions were made based on their feedback. Pilot testing of the IIS and follow-up focus groups were then conducted among all departmental clinicians to solicit additional feedback and drive further revisions. Finally, the IIS system was piloted among providers working during the 2023 Pan American and Parapan American Games to refine the system for future Games. After reviewing all potential software platform options (electronic medical record [EMR] system, athlete management systems, secure data collection platforms), Qualtrics (Qualtrics, Provo, UT, USA) was selected to host the IIS system. This choice was made due to the inability of the EMR and athlete-management systems to make frequent updates, modify existing questions, and provide the necessary form logic for the variety of scenarios in which the IIS system would be deployed. Feedback from the department's leadership and clinicians resulted in a number of changes, most notably being the ability to enter multiple diagnoses for a single injury event. Additionally, clinician feedback resulted in the creation of additional diagnostic codes not currently present in the OSIICS v14.0 diagnostic coding system, adding "non-sport" as an additional variable for injury setting, and developing a system for reporting return-to-sport date for time-loss injuries. Discussion: A multi-stage process of extensive planning, stakeholder feedback, and ongoing updates is required in order to successfully develop and implement an IIS system within a National Olympic and Paralynpic Committee. This process can be used to inform the development and implementation of IIS systems in other sporting organizations. [ABSTRACT FROM AUTHOR]

As gallium oxide-based heterojunction devices gain prominence, low-resistance contacts to aluminum gallium oxide material are of increasing importance for high performance and access to modulation doped layers. Here, the activation of ion-implanted silicon donors is investigated as a function of donor density from 5 × 1018 cm−3 to 1 × 1020 cm−3, activation anneal duration from 6 s to 600 s, and activation temperature from 900°C to 1140°C. Importantly, ohmic behavior was achievable across a reasonably wide process window at moderate to high doping concentrations. Specific contact resistance of 1 × 10−3 Ω cm2 and sheet resistance of 2.8 kΩ/□ were achieved for a 60 nm-deep 1 × 1020 cm−3 box implant after activation at 1000°C for 6 s with standard Ti/Au contacts. Under these conditions, an activation efficiency of 7% was observed with Hall mobility of ~32 cm2/Vs. Furthermore, we demonstrate a Schottky diode formed of implanted material with a rectification ratio > 106 and further confirm the Hall carrier density results using capacitance–voltage profiling analysis. Finally, we show the significant impact of anneal duration and the potential for deleterious over-annealing which reduces the active carrier density, mobility, and resultant material conductivity. [ABSTRACT FROM AUTHOR]

Platinum oxide (PtOx) Schottky contacts on degenerately doped β-Ga2O3 substrates show an increased barrier height of 85% and 64% when compared to nickel and platinum Schottky contacts, respectively. At low reverse voltage bias, the reverse leakage current of the PtOx Schottky barrier diodes was approximately 5–6 orders of magnitude lower than the reference evaporated Ni and Pt Schottky contacts. PtOx Schottky contacts were deposited using reactive sputtering on highly doped (8 × 1018 cm−3) ( 2 ¯ 01 ) β-Ga2O3:Sn substrates grown by the edge-defined film-fed growth (EFG) method. All Schottky metals were capped with evaporated Au. Capacitance–voltage and temperature-dependent current–voltage measurements were performed in order to extract the barrier height of the PtOx Schottky contact. Analysis of the diode ideality factors reveal that the PtOx Schottky contacts on highly doped β-Ga2O3 do not follow the thermionic field emission model and are impacted by inhomogeneous barrier height distribution. This work highlights the significance of PtOx Schottky contacts for β-Ga2O3-based power devices as a means for reducing leakage current. This work also holds relevance for low-voltage applications, where Schottky contacts for degenerately doped semiconductors can enable new electronic device applications. [ABSTRACT FROM AUTHOR]

Semiconductor wafer manufacturing relies on the precise control of various performance metrics to ensure the quality and reliability of integrated circuits. In particular, GaN has properties that are advantageous for high voltage and high frequency power devices; however, defects in the substrate growth and manufacturing are preventing vertical devices from performing optimally. This paper explores the application of machine learning techniques utilizing data obtained from optical profilometry as input variables to predict the probability of a wafer meeting performance metrics, specifically the breakdown voltage (Vbk). By incorporating machine learning techniques, it is possible to reliably predict performance metrics that cause devices to fail at low voltage. For diodes that fail at a higher (but still below theoretical) breakdown voltage, alternative inspection methods or a combination of several experimental techniques may be necessary. [ABSTRACT FROM AUTHOR]

The effects of acute exercise on the cortisol awakening response (CAR), characterized by the rapid increase in cortisol concentrations within the 30–45 min following sleep offset has yet to be fully elucidated. Thus, our study investigated the effects of late-evening acute exercise on the CAR the following morning. We hypothesized that exercise would have a significant effect on the CAR the following morning. Twelve participants (mean (SD): age = 23 (4) years; mass = 76.8 (8.7) kg; height = 175.6 (5.0) cm; V ˙ O2max = 48.9 (7.5) ml.kg−1.min−1) reported to the laboratory in the evening (1800 h) on two occasions and were randomly assigned to either exercise for one hour (70–75% of maximal power output) or rest condition. Blood and saliva samples were assayed for cortisol. Mixed-effects models determined the effect of exercise on the cortisol response post-waking in both blood and saliva. Participants demonstrated an average exercise-induced increase in circulating cortisol of 477.3%, with actual mean (SD) heart rate relative to maximum of 87.04% (6.14%). Model results demonstrated a negative effect for exercise condition when modeling the serum and salivary cortisol responses to awakening via a quadratic growth model (serum, βCondition = − 42.26 [95% CI − 64.52 to − 20.01], p < 0.001; saliva, βCondition = − 11.55 [95% CI − 15.52 to − 7.57], p < 0.001). These results suggest that cortisol concentrations in saliva and blood are significantly lower the morning following a prior evening exercise session. Therefore, the CAR may serve as a useful biomarker to monitor responses to exercise training, although the underlying mechanism for these decreases in the CAR should be investigated further. [ABSTRACT FROM AUTHOR]

Purpose of Review: Clonal hematopoiesis (CH) refers to the expansion of hematopoietic stem cell clones and their cellular progeny due to somatic mutations, mosaic chromosomal alterations (mCAs), or copy number variants which naturally accumulate with age. CH has been linked to increased risk of blood cancers, but CH has also been linked to adverse cardiovascular outcomes. Recent Findings: A combination of clinical outcome studies and mouse models have offered strong evidence that CH mutations either correlate with or cause atherosclerosis, diabetes mellitus, chronic kidney disease, heart failure, pulmonary hypertension, aortic aneurysm, myocardial infarction, stroke, aortic stenosis, poor outcomes following transcatheter aortic valve replacement (TAVR) or orthotopic heart transplant, death or need of renal replacement therapy secondary to cardiogenic shock, death from cardiovascular causes at large, and enhance anthracycline cardiac toxicity. Mechanistically, some adverse outcomes are caused by macrophage secretion of IL-1β and IL-6, neutrophil invasion of injured myocardium, and T-cell skewing towards inflammatory phenotypes. Summary: CH mutations lead to harmful inflammation and arterial wall invasion by bone marrow-derived cells resulting in poor cardiovascular health and outcomes. Blockade of IL-1β or JAK2 signaling are potential avenues for preventing CH-caused cardiovascular morbidity and mortality. [ABSTRACT FROM AUTHOR]

To improve the manufacturing process of GaN wafers, inexpensive wafer screening techniques are required to both provide feedback to the manufacturing process and prevent fabrication on low quality or defective wafers, thus reducing costs resulting from wasted processing effort. Many of the wafer scale characterization techniques—including optical profilometry—produce difficult to interpret results, while models using classical programming techniques require laborious translation of the human-generated data interpretation methodology. Alternatively, machine learning techniques are effective at producing such models if sufficient data is available. For this research project, we fabricated over 6000 vertical PiN GaN diodes across 10 wafers. Using low resolution wafer scale optical profilometry data taken before fabrication, we successfully trained four different machine learning models. All models predict device pass and fail with 70–75% accuracy, and the wafer yield can be predicted within 15% error on the majority of wafers. [ABSTRACT FROM AUTHOR]

To improve the manufacturing of vertical GaN devices for power electronics applications, the effects of defects in GaN substrates need to be better understood. Many non-destructive techniques including photoluminescence, Raman spectroscopy and optical profilometry, can be used to detect defects in the substrate and epitaxial layers. Raman spectroscopy was used to identify points of high crystal stress and non-uniform conductivity in a substrate, while optical profilometry was used to identify bumps and pits in a substrate which could cause catastrophic device failures. The effect of the defects was studied using vertical P-i-N diodes with a single zone junction termination extention (JTE) edge termination and isolation, which were formed via nitrogen implantation. Diodes were fabricated on and off of sample abnormalities to study their effects. From electrical measurements, it was discovered that the devices could consistently block voltages over 1000 V (near the theoretical value of the epitaxial layer design), and the forward bias behavior could consistently produce on-resistance below 2 mΩ cm2, which is an excellent value considering DC biasing was used and no substrate thinning was performed. It was found that high crystal stress increased the probability of device failure from 6 to 20%, while an inhomogeneous carrier concentration had little effect on reverse bias behavior, and slightly (~ 3%) increased the on-resistance (Ron). Optical profilometry was able to detect regions of high surface roughness, bumps, and pits; in which, the majority of the defects detected were benign. However a large bump in the termination region of the JTE or a deep pit can induce a low voltage catastrophic failure, and increased crystal stress detected by the Raman correlated to the optical profilometry with associated surface topography. [ABSTRACT FROM AUTHOR]

In light of the importance of selective area doping in GaN to enable planar process technology, and to avoid the complications from the etch/regrowth process, ion implantation is the recognizable alternative. Annealing to activate dopant species and repair the damage to a crystal poses a challenge for GaN since the material will decompose to Ga + N2 at atmospheric pressure and relevant temperatures. In this research, in situ high- and low-temperature epitaxial and ex situ sputtered AlN caps were examined in different stacking arrangements to study the optimum conditions for Mg ion implantation and activation. Concurrently, a matrix of different implantation doses was also investigated to better understand the dose-dependent activation. Each sample has a unique cap stack and four different implant doses, including an unimplanted reference quadrant. The results show that poorer quality cap films enable nitrogen to leave the crystal during annealing and leave nitrogen vacancies behind. Furthermore, a high dose is needed at the surface to facilitate ohmic contact formation. The results suggest that in situ epitaxial-grown AlN caps are more suitable for GaN activation annealing, and high-temperature thin caps provide the best barrier to prevent crystal disintegration. We reveal a timely strategy for preserving the quality of GaN crystal structure during the electrical activation of the ion-implanted Mg atoms. This work provides valuable information that bridges the gap between device processing and electrical characterization of GaN devices, presenting a clear path towards achieving an electrical activation of implanted Mg while maintaining the integrity of the crystalline structure of GaN. [ABSTRACT FROM AUTHOR]

Present GaN technology consists primarily of heteroepitaxial, lateral high electron mobility transistors; however, high-power devices would be much more efficiently manufactured with a vertical geometry due to better blocking voltage scaling. This technology has yet to be realized due to the inconsistency of GaN wafer properties. These inconsistencies can be detected with several long-range, non-destructive techniques including Raman spectroscopy, optical profilometry, and photoluminescence mapping. In particular, Raman spectroscopy is an effective tool for determining the carrier concentration of GaN substrates and whether the wafers are uniform or inhomogeneous. In this work, vertical p-i-n GaN diodes are fabricated using both uniform and inhomogeneous wafers determined by using the A1 Raman peak position to monitor carrier concentration. The inhomogeneous samples have regular patterns of varying conductivity as a result of electron-donating defects brought about by changes in crystal stress. By avoiding these defects, we have found that diode performance improves by increasing the +/− 10 V rectification ratio by up to a factor of 5X and reducing the 200 V reverse bias leakage current by several orders of magnitude. Using the higher quality substrates with uniform electron carrier concentrations can improve the rectification ratio by another order of magnitude. [ABSTRACT FROM AUTHOR]

Background: The cortisol awakening response (CAR) has been used as a biomarker of stress response in a multitude of psychological investigations. While a myriad of biochemical responses have been proposed to monitor responses to exercise training, the use of CAR within the exercise and sports sciences is currently limited and is a potentially underutilized variable. Therefore, the purpose of this review was to collate studies that incorporate both exercise and CAR, in an effort to better understand (a) whether CAR is a useful marker for monitoring exercise stress and (b) how CAR may be most appropriately used in future research. Methods: A systematic review of the literature was conducted, following PRISMA guidelines. Searches were conducted using PubMed, SportDISCUS, Scopus, and PsychInfo databases, using search terms related toCAR and exercise and physical activity. Results: 10,292 articles were identified in the initial search, with 32 studies included in the final analysis. No studies investigated the effects of laboratory-controlled exercise on CAR. Variable effects were observed, possibly due to inconsistencies in study design, methodology, population, and CAR analysis. The available literature suggests a threshold of exercise may be required to alter the HPA axis and affect CAR. Moreover, CAR may represent a combination of previous exercise load and upcoming stress, making current interpretation of field-based observational research challenging. Conclusions: More research is needed to fully elucidate the influence of exercise on CAR and address a number of gaps in the literature, including controlling exercise load, consistent sample collection, and CAR calculation and analysis. [ABSTRACT FROM AUTHOR]

Purpose: Cortisol (C) and testosterone (T) are impacted significantly by prolonged endurance exercise with inverse responses. Increases in C are witnessed concurrently with decrements in T, possibly impacting recovery. This study was conducted to assess the dynamics of C and free T (fT) concentration and recovery time following an exhaustive endurance exercise session (EES).Methods: 12 endurance-trained males (X ± SD: VO2max 66.3±4.8 ml/kg/min, age 22.8 ± 3.1 years, body fat 11.0 ± 1.4 %, training 7.1 ± 3.2 years) completed a treadmill EES at ventilatory threshold (74.7 ± 4.6 % of VO2max; 96.9 ± 10.8 min). Basal blood C and fT were collected at baseline: -48, -24 h, and immediately before (0 h) the EES as well as immediately (+0 h), +24 h, +48 h, and +72 h after the EES. Blood glucose (G) was measured to confirm no undue influence on C. Statistically data were analyzed with repeated measures ANOVA (LSD post hoc).Results: C (nmol/L) increased significantly from -48 h (321 ± 59) to +0 h (701 ± 178) (p < 0.001), and displayed a baseline overshoot with +24 h (209 ± 67) being significantly lower than -48 and +0 h (p < 0.03). fT (pmol/L) decreased significantly from -48 h (161 ± 40) to +0 h (106 ± 38) (p < 0.01) and remained lower at +24 h (110 ± 33) and +48 h (129 ± 30) (p < 0.001). G remained stable throughout. A moderately negative correlation (r = -0.636, p < 0.026) was found between C and fT at +0 h.Conclusions: EES recovery may require 48 h for C and 72 h for fT to return to baseline values. Furthermore, C and fT were only correlated immediately post-exercise. Future research should perform more frequent measurements throughout time course. [ABSTRACT FROM AUTHOR]

Cancer treatment is associated with adverse changes in strength, body composition, physical function, and quality of life. Exercise training reduces cancer incidence and mortality rates and may offset some of the treatment-related effects. To determine the independent effects of strength training (ST) on the effects of cancer treatment, an initial search was performed in March and then updated in November 2015. Additional articles (ST) on strength, body composition, aerobic capacity, functional assessments, and psychosocial parameters were included. Excluded studies had no objective strength measurement or combined ST with additional exercise. Mean and standard deviations from 39 studies across seven cancer types were extracted for main outcomes. ST-induced change scores with 95 % confidence intervals were calculated and were evaluated with paired t tests, where appropriate. Twenty to fifty percent improvements in maximal strength were observed, indicating that the ST programs were effective. Physical function was also enhanced (7–38 %), although gains were less consistent. Body composition and psychosocial changes were rare, with only a few changes in selected cancer types. As such, ST appears to promote benefits that may be specific to cancer types. Strength was the only consistent outcome that improved in all cancer survivors. However, these gains in strength are still of tremendous importance, given its impact on functionality and quality of life. Several practical considerations for exercise testing, training, and data reporting are presented for consideration to improve the overall depth of the field. [ABSTRACT FROM AUTHOR]

Multicycle rapid thermal annealing (MRTA) is shown to reduce the defect density of molecular beam epitaxially grown AlN films. No damage to the AlN surface occurred after performing the MRTA process at 1520°C. However, the individual grain structure was altered, with the emergence of step edges. This change in grain structure and diffusion of AlN resulted in an improvement in the crystalline structure. The Raman E linewidth decreased, confirming an improvement in crystal quality. The optical band edge of the AlN maintained the expected value of 6.2 eV throughout MRTA annealing, and the band edge sharpened after MRTA annealing at increased temperatures, providing further evidence of crystalline improvement. X-ray diffraction shows a substantial improvement in the (002) and (102) rocking curve FWHM for both the 1400 and 1520°C MRTA annealing conditions compared to the as-grown films, indicating that the screw and edge type dislocation densities decreased. Overall, the MRTA post-growth annealing of AlN lowers defect density, and thus will be a key step to improving optoelectronic and power electronic devices. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

comparative study of AlGaN/GaN high-electron-mobility transistor (HEMT) surface passivation using ex situ and in situ deposited SiN is presented. Performing ex situ SiN passivation increased the reverse gate leakage and off-state channel leakage by about three orders of magnitude. The in situ SiN layer was characterized using transmission electron microscopy (TEM) and capacitance-voltage (CV) measurements. Photoluminescence (PL) spectra indicated a reduction of nonradiative recombination centers in in situ SiN-passivated samples, indicating improved crystal quality. CV measurements indicated a reduction of surface state density as well, and thus better overall passivation using in situ SiN. Electroluminescence (EL) images of the channel regions in AlGaN/GaN HEMT devices operating in forward blocking mode with up to 400 V drain bias demonstrated reduced channel emission profiles of in situ-passivated devices. Compared with a nonpassivated reference sample, the reduced EL emission profiles correlated with a reduced channel temperature on ex situ SiN-passivated devices. [ABSTRACT FROM AUTHOR]

A new Wells–Dawson sandwich polyoxometalate, $$\alpha\alpha\alpha\alpha$$ -[(NaOH2)2(CuII)2 (P2W15O56)2]18− ( 2P), has been obtained in good yield by the dissolution of solid $$\alpha$$ -Na12[P2W15O56]·18H2O in an aqueous solution of Cu(II) and L-glutamic acid at pH 10. The arsenic analogue, $$\alpha\alpha\alpha\alpha$$ -[(NaOH2)2(CuII)2(As2W15O56)2]18− ( 2As), is likewise prepared by using Na12[As2W15O56]·21H2O instead of Na12[P2W15O56]·18H2O. Diffraction quality crystals of both 2P and 2As were obtained by slow evaporation in air over several days. The X-ray structures of 2P and 2As reveal that two Cu(II) atoms are sandwiched between two $$\alpha$$ -[P2W15O56]12− or two $$\alpha$$ -[As2W15O56]12− ligands, respectively, while the other two positions of the central belt unit are occupied by two Na+ cations. Higher yields of 2As can be obtained by mixing CuCl2·2H2O and $$\alpha$$ [Na12As2W15O56]·21H2O in acetate buffer. The electrochemistry of 2P and 2As is characterized by cyclic voltammograms in which the reduction of the Cu(II) centers is close to the redox pattern of the W-centers. The two Cu(II)-centers are simultaneously reduced to Cu(0); the separate steps could not be resolved for the individual Cu(II) centers. Complexes 2P and 2As constitute the second example, after $$\alpha\alpha\alpha\alpha$$ -[(NaOH2)2(FeIII)2(P2W15O56)2]16− ( 1P) and $$\alpha\alpha\alpha\alpha$$ -[(NaOH2)2(FeIII)2(As2W15O56)2]16− ( 1As), of a transition-metal-substituted sandwich polyoxometalate containing two electroactive d-electron metals. [ABSTRACT FROM AUTHOR]