Dynamic Responses of Female Volunteers in Rear Impact Sled Tests at Two Head Restraint Distances

The objective of this study was to assess the biomechanical and kinematic responses of female volunteers with two different head restraint (HR) configurations when exposed to a low-speed rear loading environment. A series of rear impact sled tests comprising eight belted, near 50th percentile female volunteers, seated on a simplified laboratory seat, was performed with a mean sled acceleration of 2.1 g and a velocity change of 6.8 km/h. Each volunteer underwent two tests; the first test configuration, HR10, was performed at the initial HR distance ∼10 cm and the second test configuration, HR15, was performed at ∼15 cm. Time histories, peak values and their timing were derived from accelerometer data and video analysis, and response corridors were also generated. The results were separated into three different categories, HR10C (N = 8), HR15C (N = 6), and HR15NC (N = 2), based on: (1) the targeted initial HR distance [10 cm or 15 cm] and (2) whether the volunteers’ head had made contact with the HR [Contact (C) or No Contact (NC)] during the test event. The results in the three categories deviated significantly. The greatest differences were found for the average peak head angular displacements, ranging from 10° to 64°. Furthermore, the average neck injury criteria (NIC) value was 22% lower in HR10C (3.9 m2/s2), and 49% greater in HR15NC (7.4 m2/s2) in comparison to HR15C (5.0 m2/s2). This study supplies new data suitable for validation of mechanical or mathematical models of a 50th percentile female. A model of a 50th percentile female remains to be developed and is urgently required to complement the average male models to enhance equality in safety assessments. Hence, it is important that future protection systems are developed and evaluated with female properties taken into consideration too. It is likely that the HR15 test configuration is close to the limit for avoiding HR contact for this specific seat setup. Using both datasets (HR15C and HR15NC), each with its corresponding HR contact condition, will be possible in future dummy or model evaluation.

Core Temperature Parameters in Elite Sailors during the Tokyo 2020 Olympic Test Event

Objective On the eve of the summer Olympic Games in Tokyo research focus has shifted on the core temperature responses of elite athletes competing in the heat. In the absence of the field data of core temperature during Olympic sailing competition aim of the present study was to identify core temperature response during the Tokyo 2020 Olympic Test Event. Methods Four elite athletes from Olympic sailing (177.5±5.2 cm, 71.1±7.4 kg, body mass index 22.5±1.4 kg/m2, 24.8±3.7 yrs, VO2max 50.6±7.2 mL/min/kg)): 2 males and 2 females participated in the study. Core temperature was recorded using e-Celsius ingestible capsules, heart rate using a heart rate monitor. Ambient conditions in direct sunlight were measured using portable meteo station. Results Core temperature was recorded at water environment via an ingestible capsule in 4 sailors during the training (T), and competition (C), respectively. Ambient conditions in direct sunlight were hot and humid: during training temperature were 30.9°C±1.7°C and relative humidity 81.4%±2.8%, corresponding to a wet-bulb globe temperature of 41°C±4°C and during competition temperature was 31.2°C±2.3°C and relative humidity 87.2%±4.4%, corresponding to a wet-bulb globe temperature of 45.2°C±8.9°C. Core temperature increased during training reaching higher peak values (38.6°C±0.4°C) and during competition (38.9°C±0.4°C). The highest temperature recorded was 39.4°C (C). Conclusion The current study provides unique information into the core temperature parameters under heat stress in elite Olympic sailors during training and race event.

Risk of Subsequent HIV Infection Following Sexually Transmissible Infections Among Men Who Have Sex With Men

Background HIV and bacterial sexually transmissible infection (STI) notifications among men who have sex with men (MSM) have increased in Australia and many other countries. The relationship between HIV infection and other STIs has been demonstrated previously. However, the relationship between the cumulative history of STIs and subsequent HIV infection remains largely unexplored and limits our understanding of the mechanisms underpinning the elevated HIV risk. Methods Data from HIV-negative MSM who attended high–HIV caseload primary care clinics in Melbourne, Australia, from 2007 to 2014 with 2 or more HIV and STI tests were included. Controlling for sexual behaviors self-reported at clinic visits, discrete time survival analyses using generalized linear modeling estimated the effect of an STI at the prior test event and the cumulative history of STIs (none, 1, 2, or more [repeated]) on risk of HIV infection. Results A total of 8941 MSM met the study criteria; 227 (2.5%) were diagnosed with HIV over the follow-up period. Adjusting for sexual behaviors, a cumulative history of repeated rectal gonorrhea infections (adjusted hazard ratio [aHR], 6.27; 95% confidence interval [CI], 2.68–14.50) and a single rectal gonorrhea infection (aHR, 2.09; 95% CI, 1.15–3.79) were associated with increased HIV infection risk. Conclusions Repeated and single rectal gonorrhea infections were independently associated with increased HIV infection risk. These findings suggest that MSM with any history of rectal gonorrhea, particularly repeat rectal gonorrhea, represent a group for whom preventive interventions for HIV should be emphasized.

Is PAX3-FOXO1 associated with worse outcome in adults with rhabdomyosarcoma (RMS)?

e22525 Background: Rhabdomyosarcoma (RMS) is a rare soft tissue sarcoma in adults. The PAX3-FOXO1 fusion gene is associated with alveolar rhabdomyosarcoma. PAX3-FOXO1 results from a stable reciprocal translocation of chromosomes 2 and 13, which fuses in-frame the DNA binding domain of PAX3 with the transactivation domain of FOXO1. Occasionally, PAX7-FOXO1 is expressed. In children, the PAX3-FOXO1 fusion gene is associated with worse outcome. We evaluated the prognostic role of FOXO1 fusion status in adults with RMS treated in a single, large volume sarcoma centre. Methods: A retrospective review of adult RMS patients (pts) diagnosed from 1984 to 2018 was done. Information on demographics, treatment, fusion status and survival was collected. Primary favourable site was defined as tumour arising in orbit, non-bladder/prostate genitourinary system and non-parameningeal head and neck. Factors were compared using Fisher’s Exact test. Event-free survival (EFS) was estimated by the Kaplan-Meier method and compared with log rank test. FOXO1 fusion status was coded as FP (fusion positive) or FN (fusion negative). Results: Of 134 pts identified in our database, fusion testing was performed in 55 (41%). Of these, PAX3 fusion was detected in 22 (40%). PAX7 was not detected. The median age of FP and FN pts was 25 yrs (range 18, 90) and 27 yrs (range 18, 65), respectively. Gender distribution was similar between FP and FN. Favourable site was seen in 13 (60%) FP and 21 (64%) FN. Nodal disease was present in 21 (95%) FP and 21 (64%) FN (p = 0.02). Distant metastases were present in 10 (45%) FP and 9 (27%) FN (n.s.). Treatment received was as follows for FP and FN, respectively: chemotherapy (21(95%), 33(100%)), radiation (14(64%), 22(67%)) and surgery (4(18%), 17(52%)). 5-yr EFS for pts without distant metastases was 27% (CI 22.6-76.6) and 46% (CI 21.5 – 70.5) for FP and FN respectively (n.s.). Conclusions: FP and FN RMS occurs in adults of all ages. Similar to children, adults with FP are more likely to present with nodal disease. Our study did not show that fusion status was associated with poorer EFS in adult RMS, however, larger series are needed to confirm this preliminary data.

What pacing strategy 800m and 1500m swimmers use?

Pacing strategy (PS) has a decisive impact on performance, especially on long-term races.The objective of this study is to characterize the PS used in swimming races of 800m and 1500m freestyle by the finalists of the Olympic trials of the United States, Europe and Brazil,and the Olympic finalists of 2016.Time partials of 63 athletes were analyzed using a decision tree and the CHAID method. The results showed that parabolic was adopted by swimmers of 800m, they start in first lap (29.67 ± 0.88 s), followed by an increase in time (+1.77 s) and a subsequent increase in time (32.04 ± 0.89 s), at the end, the swimmers presented an acceleration,reducing the average of the to 31.44 s. And by the free 1500m swimmers, divided into blocks with a faster average start (29.25 ± 1.15 s), half of the slowest race (30.30 ± 0.76 s), and a new acceleration at the end of the event (29.92 ± 1.12 s), both in the selective Olympic Games and the 2016 and 2016 Olympic final.The worst partials times were observed in the Brazilian Selective (Test Event) (31.11 ± 0.78 s). Medalist, despite presetting the same OS, can sustain a better rhythm throughout he 800m (31.52 ± 1.03 s) and 1500-m (29.80 ± 0.78). We conclude that parabolic PS is the optimal strategy adopted by swimmers of 800-m and 1500m freestyle.