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Purpose of reviewClonal 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 findingsA 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. 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.

Adequate sleep is crucial for elite athletes' recovery, performance readiness, and immune response. Establishing reference ranges for elite athletes enables appropriate contextualization for designing and targeting sleep interventions. Purpose: To establish sleep-quality reference ranges for Olympic and Paralympic cohorts using the Pittsburgh Sleep Quality Index (PSQI) and explore differences based on sex and sport types. Methods: Team USA athletes (men = 805, women = 798) completed the PSQI as part of a health-history questionnaire. Descriptive statistics were used to create reference ranges and linear models, and χ2 test of independence determined differences in PSQI global and component scores between sex, games, season, and participation. Results: Six hundred thirty-two (39.43%) athletes reported poor sleep (PSQIGlobal ≥ 5). Men displayed later bedtimes (P =.006), better global PSQI scores, shorter sleep latency, less sleep disturbance, and less use of sleep medication than women (all P <.001). Winter Games participants had later bedtime (P =.036) and sleep offset time (P =.028) compared with Summer Games athletes. Team-sport athletes woke earlier than individual-sport athletes (P <.001). Individual-sport athletes were more likely to have low (P =.005) and mild (P =.045) risk for reduced sleep duration than team-sport athletes. Conclusion: These data provide PSQI-specific reference ranges to identify groups at greatest risk for poor sleep, who may benefit most from targeted sleep interventions. [ABSTRACT FROM AUTHOR]

Purpose: Transmeridian travel is common for elite athletes participating in competitions and training. However, this travel can lead to circadian misalignment wherein the internal biological clock becomes desynchronized with the light–dark cycle of the new environment, resulting in performance decrement and potential negative health consequences. Existing literature extensively discusses recommendations for managing jet lag, predominantly emphasizing light-based interventions to synchronize the internal clock with the anticipated time at the destination. Nevertheless, visually impaired (VI) athletes may lack photoreceptiveness, diminishing or nullifying the effectiveness of this therapy. Consequently, this invited commentary explores alternative strategies for addressing jet lag in VI athletes. Conclusions: VI athletes with light perception but reduced visual acuity or visual fields may still benefit from light interventions in managing jet lag. However, VI athletes lacking a conscious perception of light should rely on gradual shifts in behavioral factors, such as meal timing and exercise, to facilitate the entrainment of circadian rhythms to the destination time. Furthermore, interventions like melatonin supplementation may prove useful during and after travel. In addition, it is recommended that athlete guides adopt phase-forward or phase-back approaches to synchronize with the athlete, aiding in jet-lag management and optimizing performance. [ABSTRACT FROM AUTHOR]

The physical demands of a single long-distance triathlon (LDT) are sufficient to cause robust physiological perturbations. In this unique case study, an ultraendurance athlete completed 100 LDTs in 100 days (100LDT). Purpose: This study aims to describe and analyze this single athlete's performance, physiological biomarkers, and sleep parameters throughout the 100LDT. Methods: An ultraendurance athlete completed an LDT (2.4-mile swim, 112-mile bike ride, and 26.2-mile marathon) each day for 100 consecutive days. Physical work, physiological biomarkers, and sleep parameters were recorded each night using a wrist-worn photoplethysmographic sensor. Clinical exercise tests were performed before and after the 100LDT. Time-series analysis assessed changes in biomarkers and sleep parameters across the 100LDT, and cross-correlations considered the associations between exercise performance and physiological metrics at varying time lags. Results: The swim and cycling performances varied across the 100LDT, while the run was relatively stable. Resting heart rate, heart-rate variability, oxygen saturation, sleep score, light sleep, sleep efficiency, and sleep duration were all best characterized by cubic models. Additional post hoc subanalyses suggest that the first half of the 100LDT most influenced these dynamics. Conclusions: The 100LDT resulted in nonlinear alterations to physiological metrics. This world record was a unique event but allows valuable insights into the limits of human endurance performance. [ABSTRACT FROM AUTHOR]

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]

The neurocognitive health effects of repetitive head impacts have been examined in many sports. However, characterizations of head impacts for sliding-sport athletes are lacking. To describe head impact kinematics and injury epidemiology in elite athletes during the 2021–2022 Bobsleigh World Cup season. Cross-sectional study. On-track training and competitions during the Bobsleigh World Cup season. Twelve elite bobsleigh athletes (3 pilots [1 female], 9 push athletes [5 females]; age = 30 ± 5 years; female height and weight = 173 ± 8 cm and 75 ± 5 kg, respectively; male height and weight = 183 ± 5 cm and 101 ± 5 kg, respectively). Athletes wore an accelerometer-enabled mouthguard to quantify 6-degrees-of-freedom head impact kinematics. Isometric absolute and relative neck strength, number of head acceleration events (HAEs), workload (J), peak linear velocity (m·s−1), peak angular velocity (rad·s−1), peak linear acceleration (g), and peak angular acceleration (rad·s−2) were derived from mouthguard manufacturer algorithms. Linear mixed-effect models tested the effects of sex (male versus female), setting (training versus competition), and position (pilot versus push athlete) on the kinematic variables. A total of 1900 HAEs were recorded over 48 training and 53 competition days. No differences were found between the number of HAEs per run per athlete by sex (incidence rate ratio [IRR] = 0.82, P =.741), setting (IRR = 0.94, P =.325), or position (IRR = 1.64, P =.463). No sex differences were observed for workload (mean ± SD: males = 3.3 ± 2.2 J, females = 3.1 ± 1.9 J; P =.646), peak linear velocity (males = 1.1 ± 0.3 m·s−1, females = 1.1 ± 0.3 m·s−1; P =.706), peak angular velocity (males = 4.2 ± 2.1 rad·s−1, females = 4.7 ± 2.5 rad·s−1; P =.220), peak linear acceleration (male = 12.4 ± 3.9g, females = 11.9 ± 3.5g; P =.772), or peak angular acceleration (males = 610 ± 353 rad·s−2, females = 680 ± 423 rad·s−2; P =.547). Also, no effects of setting or position on any kinematic variables were seen. Male athletes had greater peak neck strength than female athletes for all neck movements, aside from right-side flexion (P =.085), but no sex differences were noted in relative neck strength. We provide a foundational understanding of the repetitive HAEs that occur in bobsleigh athletes. Future authors should determine the effects of repetitive head impacts on neurocognitive function and mental health. [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]

Several cardiovascular disease (CVD) risk factors (e.g., hypertension, poor glycemic control) can affect and be affected by autonomic nervous system (ANS) activity. Since excess adiposity can influence CVD development through its effect on hypertension and diabetes mellitus, it is important to determine how adiposity and altered ANS activity are related. The present study employed structural equation modeling to investigate the relation between adiposity and ANS activity both directly and indirectly through biological variables typically associated with glycemic impairment and cardiac stress in older adults. Utilizing the Atherosclerosis Risk in Communities (ARIC) dataset, 1,145 non-smoking adults (74±4.8 yrs, 62.8% female) free from known CVD, hypertension, and diabetes and not currently taking beta-blockers were evaluated for fasting blood glucose (FBG), insulin, and HbA1c concentrations, waist circumference (WC), blood pressure (BP), and markers of ANS activity. WC was recorded just above the iliac crest and was used to reflect central adiposity. Resting 2-minute electrocardiograph recordings, pulse wave velocity, and ankle-brachial index data were used to assess the root mean square of successive differences in RR intervals (RMSSD) and the pre-ejection period (PEP), markers of parasympathetic and sympathetic activity, respectively. FBG, insulin, and HbA1c inferred a latent variable termed glycemic impairment (GI), whereas heart rate and diastolic BP inferred a latent variable termed cardiac stress (CS). The structural equation model fit was acceptable [root mean square error of approximation = 0.050 (90% CI =.036,.066), comparative fit index =.970, Tucker Lewis Index = 0.929], with adiposity having both significant direct (β = 0.208, p = 0.018) and indirect (β = -.217, p =.041) effects on PEP through GI. Adiposity displayed no significant direct effect on RMSSD. CS displayed a significant pathway (β = -0.524, p = 0.035) on RMSSD, but the indirect effect of WC on RMSSD through CS did not reach statistical significance (β = -0.094, p = 0.137). These results suggest that adiposity's relation to ANS activity is multifaceted, as increased central adiposity had opposing direct and indirect effects on markers of sympathetic activity in this population of older adults. [ABSTRACT FROM AUTHOR]

The low thermal conductivity of β-Ga2O3 is a significant concern for maximizing the potential of this ultra-wide bandgap semiconductor as a power switching device technology. Here, we report on the use of nanocrystalline diamond (NCD) deposited via microwave plasma enhanced chemical vapor deposition (MP-CVD) as a top-side, device-level thermal management solution on a lateral β-Ga2O3 transistor. NCD was grown via MP-CVD on β-(AlxGa1−x)2O3/β-Ga2O3 heterostructures prior to the gate formation of the field-effect transistor. A reduced growth temperature of 400 °C and a SiNx barrier layer were used to protect the oxide semiconductors from etching in the MP-CVD H2 plasma environment. Raman spectroscopy showed a highly sp3-bonded NCD film was obtained at 400 °C, with grain size of about 50–100 nm imaged via atomic force microscopy. The incorporation of the NCD heat-spreading layer resulted in a β-(AlxGa1−x)2O3/β-Ga2O3 heterostructure field-effect transistor showing a decrease in the total thermal resistance at the gate by 42%. The fabrication process, including the NCD etch in the gate region, will need to be improved to minimize the impact of these processes on important device characteristics (i.e., drain current, threshold voltage, and leakage current). [ABSTRACT FROM AUTHOR]