Empirical analysis of the impact of bow parameters on arrow velocity: A study of World Cup archers based on energy transfer and aerodynamics

This study examines the quantitative relationship between bow-and-arrow parameters and arrow velocity using empirical data collected from elite athletes at the 2025 World Archery Cup. Within the frameworks of energy-transfer mechanics and aerodynamics, this research analyzes the effects of draw weight, arrow length, and arrow mass through independent-sample t-tests, correlation analyses, and multiple-regression modeling. Results demonstrate that draw weight is the dominant determinant of arrow velocity (β = 0.843, p < 0.001), confirming the energy storage–conversion hypothesis and providing empirical validation for the traditional archery principle of the “strong bow and powerful arrow.” In contrast, arrow length and mass exhibit non-significant effects among high-level athletes, indicating that modern competitive equipment has reached a state of aerodynamic and structural optimization in which marginal parameter adjustments are absorbed by systemic equilibrium. The findings establish an integrated analytical framework of the human–bow–arrow energy system, bridging laboratory models with real-world competition data and highlighting the coupling of physical, biomechanical, and cultural dimensions in archery performance. This interdisciplinary approach provides reproducible evidence for optimizing bow-and-arrow configurations and offers a theoretical bridge between ancient embodied wisdom and contemporary scientific modeling

Seasonal variation in oxygenated organic molecules in urban Beijing and their contribution to secondary organic aerosol

Oxygenated organic molecules (OOMs) are crucial for atmospheric new particle formation and secondary organic aerosol (SOA) growth. Therefore, understanding their chemical composition, temporal behavior, and sources is of great importance. Previous studies on OOMs mainly focus on environments where biogenic sources are predominant, yet studies on sites with dominant anthropogenic emissions, such as megacities, have been lacking. Here, we conducted long-term measurements of OOMs, covering four seasons of the year 2019, in urban Beijing. The OOM concentration was found to be the highest in summer (1.6 x 10(8) cm(-3)), followed by autumn (7.9 x 10(7) cm(-3)), spring (5.7 x 10(7) cm(-3)) and winter (2.3 x 10(7) cm(-3)), suggesting that enhanced photo-oxidation together with the rise in temperature promote the formation of OOMs. Most OOMs contained 5 to 10 carbon atoms and 3 to 7 effective oxygen atoms (nO(eff) = nO - 2 x nN). The average nO(eff )increased with increasing atmospheric photo-oxidation capacity, which was the highest in summer and the lowest in winter and autumn. By performing a newly developed workflow, OOMs were classified into the following four types: aromatic OOMs, aliphatic OOMs, isoprene OOMs, and monoterpene OOMs. Among them, aromatic OOMs (29 %-41 %) and aliphatic OOMs (26 %-41 %) were the main contributors in all seasons, indicating that OOMs in Beijing were dominated by anthropogenic sources. The contribution of isoprene OOMs increased significantly in summer (33 %), which is much higher than those in the other three seasons (8 %-10 %). Concentrations of isoprene (0.2-5.3 x 10(7) cm(-3)) and monoterpene (1.1-8.4 x 10(6) cm(-3)) OOMs in Beijing were lower than those reported at other sites, and they possessed lower oxygen and higher nitrogen contents due to high NO, levels (9.5-38.3 ppbv - parts per billion by volume) in Beijing. With regard to the nitrogen content of the two anthropogenic OOMs, aromatic OOMs were mainly composed of CHO and CHON species, while aliphatic OOMs were dominated by CHON and CHON2 ones. Such prominent differences suggest varying formation pathways between these two OOMs. By combining the measurements and an aerosol dynamic model, we estimated that the SOA growth rate through OOM condensation could reach 0.64, 0.61, 0.41, and 0.30 mu g m(-3) h(-1) in autumn, summer, spring, and winter, respectively. Despite the similar concentrations of aromatic and aliphatic OOMs, the former had lower volatilities and, therefore, showed higher contributions (46 %-62 %) to SOA than the latter (14 %-32 %). By contrast, monoterpene OOMs and isoprene OOMs, limited by low abundances or high volatilities, had low contributions of 8 %-12 % and 3 %-5 %, respectively. Overall, our results improve the understanding of the concentration, chemical composition, seasonal variation, and potential atmospheric impacts of OOMs, which can help formulate refined restriction policy specific to SOA control in urban areas.Peer reviewe

Intra-Arterial Urokinase After Endovascular Reperfusion for Acute Ischemic Stroke: The POST-UK Randomized Clinical Trial

Importance. Persisting or new thrombi in the distal arteries and the microcirculation have been reported to limit the benefits of successful endovascular thrombectomy for patients with acute ischemic stroke. It remains uncertain whether intra-arterial thrombolysis by urokinase following near-complete to complete reperfusion by thrombectomy improves outcomes among patients with ischemic stroke due to large vessel occlusion.Objective. To assess the efficacy and adverse events of intra-arterial urokinase after near-complete to complete reperfusion by thrombectomy for acute ischemic stroke due to large vessel occlusion.Design, Setting, and Participants. This investigator-initiated, randomized, open-label, blinded–end point trial was implemented at 35 hospitals in China, enrolling 535 patients with proximal intracranial large vessel occlusion presenting within 24 hours of time last known well, who achieved near-complete or complete reperfusion by endovascular thrombectomy and did not receive intravenous thrombolysis prior to the procedure. Recruitment took place between November 15, 2022, and March 29, 2024, with final follow-up on July 4, 2024.Interventions. Eligible patients were randomly assigned to the intra-arterial urokinase group (a single dose of intra-arterial 100 000 IU urokinase injected in the initial target territory; n = 267) or control group (without intra-arterial thrombolysis; n = 267).Main Outcomes and Measures. The primary efficacy outcome was the percentage of patients achieving survival without disability (modified Rankin Scale score of 0 or 1) at 90 days. The primary safety outcomes were mortality at 90 days and incidence of symptomatic intracranial hemorrhage within 48 hours.Results. A total of 535 patients were enrolled (median age, 69 years; 223 [41.8%] female) and 532 (99.6%) completed the trial. The percentage of patients with survival without disability at 90 days was 45.1% (120/266) in the intra-arterial urokinase group and 40.2% (107/266) in the control group (adjusted risk ratio, 1.13 [95% CI, 0.94-1.36]; P = .19). Mortality at 90 days (18.4% vs 17.3%, respectively; adjusted hazard ratio, 1.06 [95% CI, 0.71-1.59]; P = .77) and incidence of symptomatic intracranial hemorrhage (4.1% vs 4.1%, respectively; adjusted risk ratio, 1.05 [95% CI, 0.45-2.44]; P = .91) were not significantly different between groups.Conclusions and Relevance. Among patients with acute ischemic stroke due to large vessel occlusion, adjunct intra-arterial urokinase after near-complete to complete reperfusion by endovascular thrombectomy did not significantly increase the likelihood of survival without disability at 90 days.</p

Intra-Arterial Urokinase After Endovascular Reperfusion for Acute Ischemic Stroke: The POST-UK Randomized Clinical Trial

Importance. Persisting or new thrombi in the distal arteries and the microcirculation have been reported to limit the benefits of successful endovascular thrombectomy for patients with acute ischemic stroke. It remains uncertain whether intra-arterial thrombolysis by urokinase following near-complete to complete reperfusion by thrombectomy improves outcomes among patients with ischemic stroke due to large vessel occlusion. Objective. To assess the efficacy and adverse events of intra-arterial urokinase after near-complete to complete reperfusion by thrombectomy for acute ischemic stroke due to large vessel occlusion. Design, Setting, and Participants. This investigator-initiated, randomized, open-label, blinded–end point trial was implemented at 35 hospitals in China, enrolling 535 patients with proximal intracranial large vessel occlusion presenting within 24 hours of time last known well, who achieved near-complete or complete reperfusion by endovascular thrombectomy and did not receive intravenous thrombolysis prior to the procedure. Recruitment took place between November 15, 2022, and March 29, 2024, with final follow-up on July 4, 2024. Interventions. Eligible patients were randomly assigned to the intra-arterial urokinase group (a single dose of intra-arterial 100 000 IU urokinase injected in the initial target territory; n = 267) or control group (without intra-arterial thrombolysis; n = 267). Main Outcomes and Measures. The primary efficacy outcome was the percentage of patients achieving survival without disability (modified Rankin Scale score of 0 or 1) at 90 days. The primary safety outcomes were mortality at 90 days and incidence of symptomatic intracranial hemorrhage within 48 hours. Results. A total of 535 patients were enrolled (median age, 69 years; 223 [41.8%] female) and 532 (99.6%) completed the trial. The percentage of patients with survival without disability at 90 days was 45.1% (120/266) in the intra-arterial urokinase group and 40.2% (107/266) in the control group (adjusted risk ratio, 1.13 [95% CI, 0.94-1.36]; P = .19). Mortality at 90 days (18.4% vs 17.3%, respectively; adjusted hazard ratio, 1.06 [95% CI, 0.71-1.59]; P = .77) and incidence of symptomatic intracranial hemorrhage (4.1% vs 4.1%, respectively; adjusted risk ratio, 1.05 [95% CI, 0.45-2.44]; P = .91) were not significantly different between groups. Conclusions and Relevance. Among patients with acute ischemic stroke due to large vessel occlusion, adjunct intra-arterial urokinase after near-complete to complete reperfusion by endovascular thrombectomy did not significantly increase the likelihood of survival without disability at 90 days