Effect of work:rest ratio on cycling performance following sprint interval training: A randomised control trial

Sprint interval training (SIT) has been shown to improve performance measures in a range of individuals, and it is understood that different responses can be elicited from different training protocols. However, consideration of changes in work: rest ratios could offer important insight into optimising training programmes. The purpose of this study was to investigate the effect of three different work: rest ratios on exercise performance. Thirty-six male and female participants were randomly allocated to one of three training groups, or a non-training control group. Training consisted of 10x6 second ‘all-out’ sprints on a cycle ergometer, with a 1:8, 1:10 or 1:12 work: rest ratio. Performance data, including peak power output, performance decrement, and 10km time trial performance data were collected before and after 2-weeks of SIT. There were significant (p ≤ 0.05) improvements in all parameters for the training groups, but no changes in the control condition. Peak power increased by 57.2W, 50.7W and 53.7W in the 1:8, 1:10 and 1:12 groups respectively, with no significant differences in response between conditions. Time trial performance improved significantly in all three training conditions (29.4s, 8.7s, and 25.1s in the 1:8, 1:10 and 1:12 groups), while worsening in the control group. All training conditions resulted in significant improvements in performance, but there were no significant differences in improvement for any of the groups. Any of the three stated work: rest ratios would be appropriate for use with athletes and allow some level of personal preference for those interested in using the protocol

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial.

BACKGROUND: Remote ischaemic conditioning with transient ischaemia and reperfusion applied to the arm has been shown to reduce myocardial infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). We investigated whether remote ischaemic conditioning could reduce the incidence of cardiac death and hospitalisation for heart failure at 12 months. METHODS: We did an international investigator-initiated, prospective, single-blind, randomised controlled trial (CONDI-2/ERIC-PPCI) at 33 centres across the UK, Denmark, Spain, and Serbia. Patients (age >18 years) with suspected STEMI and who were eligible for PPCI were randomly allocated (1:1, stratified by centre with a permuted block method) to receive standard treatment (including a sham simulated remote ischaemic conditioning intervention at UK sites only) or remote ischaemic conditioning treatment (intermittent ischaemia and reperfusion applied to the arm through four cycles of 5-min inflation and 5-min deflation of an automated cuff device) before PPCI. Investigators responsible for data collection and outcome assessment were masked to treatment allocation. The primary combined endpoint was cardiac death or hospitalisation for heart failure at 12 months in the intention-to-treat population. This trial is registered with ClinicalTrials.gov (NCT02342522) and is completed. FINDINGS: Between Nov 6, 2013, and March 31, 2018, 5401 patients were randomly allocated to either the control group (n=2701) or the remote ischaemic conditioning group (n=2700). After exclusion of patients upon hospital arrival or loss to follow-up, 2569 patients in the control group and 2546 in the intervention group were included in the intention-to-treat analysis. At 12 months post-PPCI, the Kaplan-Meier-estimated frequencies of cardiac death or hospitalisation for heart failure (the primary endpoint) were 220 (8·6%) patients in the control group and 239 (9·4%) in the remote ischaemic conditioning group (hazard ratio 1·10 [95% CI 0·91-1·32], p=0·32 for intervention versus control). No important unexpected adverse events or side effects of remote ischaemic conditioning were observed. INTERPRETATION: Remote ischaemic conditioning does not improve clinical outcomes (cardiac death or hospitalisation for heart failure) at 12 months in patients with STEMI undergoing PPCI. FUNDING: British Heart Foundation, University College London Hospitals/University College London Biomedical Research Centre, Danish Innovation Foundation, Novo Nordisk Foundation, TrygFonden

Dehydrocoupling of Dimethylamine Borane Catalyzed by Rh(PCy₃)₂H₂Cl

The Rh­(III) species Rh­(PCy₃)₂H₂Cl is an effective catalyst (2 mol %, 298 K) for the dehydrogenation of H₃B·NMe₂H (0.072 M in 1,2-F₂C₆H₄ solvent) to ultimately afford the dimeric aminoborane [H₂BNMe₂]₂. Mechanistic studies on the early stages in the consumption of H₃B·NMe₂H, using initial rate and H/D exchange experiments, indicate possible dehydrogenation mechanisms that invoke turnover-limiting N–H activation, which either precedes or follows B–H activation, to form H₂BNMe₂, which then dimerizes to give [H₂BNMe₂]₂. An additional detail is that the active catalyst Rh­(PCy₃)₂H₂Cl is in rapid equilibrium with an inactive dimeric species, [Rh­(PCy₃)­H₂Cl]₂. The reaction of Rh­(PCy₃)₂H₂Cl with [Rh­(PCy₃)­H₂(H₂)₂]­[BAr^F₄] forms the halide-bridged adduct [Rh­(PCy₃)₂H₂(μ-Cl)­H₂(PCy₃)₂Rh]­[BAr^F₄] (Ar^F = 3,5-(CF₃)₂C₆H₃), which has been crystallographically characterized. This dinuclear cation dissociates on addition of H₃B·NMe₂H to re-form Rh­(PCy₃)₂H₂Cl and generate [Rh­(PCy₃)₂H₂(η²-H₃B·NMe₂H)]­[BAr^F₄]. The fate of the catalyst at low catalyst loadings (0.5 mol %) is also addressed, with the formation of an inactive borohydride species, Rh­(PCy₃)₂H₂(η²-H₂BH₂), observed. On addition of H₃B·NMe₂H to Ir­(PCy₃)₂H₂Cl, the Ir congener Ir­(PCy₃)₂H₂(η²-H₂BH₂) is formed, with concomitant generation of the salt [H₂B­(NMe₂H)₂]­Cl

Initial Guidance on Use of Monoclonal Antibody Therapy for Treatment of COVID-19 in Children and Adolescents

BackgroundIn November 2020, the US Food and Drug Administration (FDA) provided Emergency Use Authorizations (EUA) for 2 novel virus-neutralizing monoclonal antibody therapies, bamlanivimab and REGN-COV2 (casirivimab plus imdevimab), for the treatment of mild to moderate coronavirus disease 2019 (COVID-19) in adolescents and adults in specified high-risk groups. This has challenged clinicians to determine the best approach to use of these products.MethodsA panel of experts in pediatric infectious diseases, pediatric infectious diseases pharmacy, pediatric intensive care medicine, and pediatric hematology from 29 geographically diverse North American institutions was convened. Through a series of teleconferences and web-based surveys, a guidance statement was developed and refined based on review of the best available evidence and expert opinion.ResultsThe course of COVID-19 in children and adolescents is typically mild and there is no high-quality evidence supporting any high-risk groups. There is no evidence for safety and efficacy of monoclonal antibody therapy for treatment of COVID-19 in children or adolescents, limited evidence of modest benefit in adults, and evidence for potential harm associated with infusion reactions or anaphylaxis.ConclusionsBased on evidence available as of December 20, 2020, the panel suggests against routine administration of monoclonal antibody therapy (bamlanivimab, or casirivimab and imdevimab), for treatment of COVID-19 in children or adolescents, including those designated by the FDA as at high risk of progression to hospitalization or severe disease. Clinicians and health systems choosing to use these agents on an individualized basis should consider risk factors supported by pediatric-specific evidence and ensure the implementation of a system for safe and timely administration that does not exacerbate existing healthcare disparities

State of the climate in 2010

Several large-scale climate patterns influenced climate conditions and weather patterns across the globe during 2010. The transition from a warm El Nino phase at the beginning of the year to a cool La Nina phase by July contributed to many notable events, ranging from record wetness across much of Australia to historically low Eastern Pacific basin and near-record high North Atlantic basin hurricane activity. The remaining five main hurricane basins experienced below-to well-below-normal tropical cyclone activity. The negative phase of the Arctic Oscillation was a major driver of Northern Hemisphere temperature patterns during 2009/10 winter and again in late 2010. It contributed to record snowfall and unusually low temperatures over much of northern Eurasia and parts of the United States, while bringing above-normal temperatures to the high northern latitudes. The February Arctic Oscillation Index value was the most negative since records began in 1950. The 2010 average global land and ocean surface temperature was among the two warmest years on record. The Arctic continued to warm at about twice the rate of lower latitudes. The eastern and tropical Pacific Ocean cooled about 1 C from 2009 to 2010, reflecting the transition from the 2009/10 El Nino to the 2010/11 La Nina. Ocean heat fluxes contributed to warm sea surface temperature anomalies in the North Atlantic and the tropical Indian and western Pacific Oceans. Global integrals of upper ocean heat content for the past several years have reached values consistently higher than for all prior times in the record, demonstrating the dominant role of the ocean in the Earth's energy budget. Deep and abyssal waters of Antarctic origin have also trended warmer on average since the early 1990s. Lower tropospheric temperatures typically lag ENSO surface fluctuations by two to four months, thus the 2010 temperature was dominated by the warm phase El Nino conditions that occurred during the latter half of 2009 and early 2010 and was second warmest on record. The stratosphere continued to be anomalously cool. Annual global precipitation over land areas was about five percent above normal. Precipitation over the ocean was drier than normal after a wet year in 2009. Overall, saltier (higher evaporation) regions of the ocean surface continue to be anomalously salty, and fresher (higher precipitation) regions continue to be anomalously fresh. This salinity pattern, which has held since at least 2004, suggests an increase in the hydrological cycle. Sea ice conditions in the Arctic were significantly different than those in the Antarctic during the year. The annual minimum ice extent in the Arctic reached in September was the third lowest on record since 1979. In the Antarctic, zonally averaged sea ice extent reached an all-time record maximum from mid-June through late August and again from mid-November through early December. Corresponding record positive Southern Hemisphere Annular Mode Indices influenced the Antarctic sea ice extents. Greenland glaciers lost more mass than any other year in the decade-long record. The Greenland Ice Sheet lost a record amount of mass, as the melt rate was the highest since at least 1958, and the area and duration of the melting was greater than any year since at least 1978. High summer air temperatures and a longer melt season also caused a continued increase in the rate of ice mass loss from small glaciers and ice caps in the Canadian Arctic. Coastal sites in Alaska show continuous permafrost warming and sites in Alaska, Canada, and Russia indicate more significant warming in relatively cold permafrost than in warm permafrost in the same geographical area. With regional differences, permafrost temperatures are now up to 2 C warmer than they were 20 to 30 years ago. Preliminary data indicate there is a high probability that 2010 will be the 20th consecutive year that alpine glaciers have lost mass. Atmospheric greenhouse gas concentrations continued to rise and ozone depleting substances continued to decrease. Carbon dioxide increased by 2.60 ppm in 2010, a rate above both the 2009 and the 1980-2010 average rates. The global ocean carbon dioxide uptake for the 2009 transition period from La Nina to El Nino conditions, the most recent period for which analyzed data are available, is estimated to be similar to the long-term average. The 2010 Antarctic ozone hole was among the lowest 20% compared with other years since 1990, a result of warmer-than-average temperatures in the Antarctic stratosphere during austral winter between mid-July and early September

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7