ABSTRACT
This study investigated the extent of injury incidence and burden in a professional women football team of the Scottish Women's Premier League during two seasons. All injuries causing time-loss or required medical attention were recorded prospectively. A total of 671 injuries, 570 requiring medical attention and 101 causing time-loss were recorded in 41 players. Injuries occurring with National Team resulted in 12% of the club's international players' lay-off. Overall injury incidence was 11.1/1000-hours and burden was 368.9 days/1000-hours. Injury incidence (23.9/1000-hours vs 8.2/1000-hours) and burden (1049.8 days/1000-hours vs 215.1 days/1000-hours) were higher for match compared to training. Foremost mechanism of match injury burden was indirect-contact, which was different than the non-contact predominantly observed for training injury burden. Injury incidence, burden and patterns differed between training, match and playing positions. Tailoring injury-risk reduction strategies considering context, circumstances and playing position deserve consideration to enhance player's injury resilience in professional women footballers.
ABSTRACT
Photolyases, a ubiquitous class of flavoproteins, use blue light to repair DNA photolesions. In this work, we determined the structural mechanism of the photolyase-catalyzed repair of a cyclobutane pyrimidine dimer (CPD) lesion using time-resolved serial femtosecond crystallography (TR-SFX). We obtained 18 snapshots that show time-dependent changes in four reaction loci. We used these results to create a movie that depicts the repair of CPD lesions in the picosecond-to-nanosecond range, followed by the recovery of the enzymatic moieties involved in catalysis, completing the formation of the fully reduced enzyme-product complex at 500 nanoseconds. Finally, back-flip intermediates of the thymine bases to reanneal the DNA were captured at 25 to 200 microseconds. Our data cover the complete molecular mechanism of a photolyase and, importantly, its chemistry and enzymatic catalysis at work across a wide timescale and at atomic resolution.
Subject(s)
Archaeal Proteins , DNA Repair , Deoxyribodipyrimidine Photo-Lyase , Methanosarcina , Pyrimidine Dimers , Archaeal Proteins/chemistry , Catalysis , Crystallography/methods , Deoxyribodipyrimidine Photo-Lyase/chemistry , DNA/chemistry , DNA/radiation effects , Methanosarcina/enzymology , Protein Conformation , Pyrimidine Dimers/chemistry , Ultraviolet RaysABSTRACT
The binding and release of ligands from their protein targets is central to fundamental biological processes as well as to drug discovery. Photopharmacology introduces chemical triggers that allow the changing of ligand affinities and thus biological activity by light. Insight into the molecular mechanisms of photopharmacology is largely missing because the relevant transitions during the light-triggered reaction cannot be resolved by conventional structural biology. Using time-resolved serial crystallography at a synchrotron and X-ray free-electron laser, we capture the release of the anti-cancer compound azo-combretastatin A4 and the resulting conformational changes in tubulin. Nine structural snapshots from 1 ns to 100 ms complemented by simulations show how cis-to-trans isomerization of the azobenzene bond leads to a switch in ligand affinity, opening of an exit channel, and collapse of the binding pocket upon ligand release. The resulting global backbone rearrangements are related to the action mechanism of microtubule-destabilizing drugs.
Subject(s)
Microtubules , Tubulin , Tubulin/metabolism , Crystallography , Ligands , Microtubules/metabolism , Crystallography, X-RayABSTRACT
Chloride transport by microbial rhodopsins is an essential process for which molecular details such as the mechanisms that convert light energy to drive ion pumping and ensure the unidirectionality of the transport have remained elusive. We combined time-resolved serial crystallography with time-resolved spectroscopy and multiscale simulations to elucidate the molecular mechanism of a chloride-pumping rhodopsin and the structural dynamics throughout the transport cycle. We traced transient anion-binding sites, obtained evidence for how light energy is used in the pumping mechanism, and identified steric and electrostatic molecular gates ensuring unidirectional transport. An interaction with the π-electron system of the retinal supports transient chloride ion binding across a major bottleneck in the transport pathway. These results allow us to propose key mechanistic features enabling finely controlled chloride transport across the cell membrane in this light-powered chloride ion pump.
Subject(s)
Betacoronavirus , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Sports , Athletes/psychology , COVID-19 , Consensus , Coronavirus Infections/diagnosis , Coronavirus Infections/epidemiology , Humans , New Zealand/epidemiology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/epidemiology , SARS-CoV-2ABSTRACT
OBJECTIVE: To evaluate the impact of Zika virus on preparation and management of the New Zealand (NZ) Olympic team. DESIGN: Descriptive manuscript. SETTING: New Zealand Olympic Health team preparation and management during the Rio de Janeiro Olympic Games, 2016. PATIENTS (OR PARTICIPANTS): New Zealand Olympic Team members. INTERVENTIONS (OR ASSESSMENT OF RISK FACTORS): This manuscript describes the approaches used by the NZ Olympic Health team to the minimization of risk from Zika virus. MAIN OUTCOME MEASURES: Although descriptive of approach forms most of the article, the results of Zika virus serology are presented. RESULTS: The NZ Olympic Health team took a proactive approach to risk mitigation, including extensive education, clothing changes, mosquito spray, mosquito nets, and voluntary postexposure testing. No positive serology was observed in those tested. CONCLUSIONS: The outbreak of Zika virus in Brazil, the associated complication of microcephaly, and the evolving understanding of virus transmission created significant uncertainty for NZ Olympic team members. The proactive approach taken by the health team to the mitigation of risk, combined with the anticipated low risk of arbovirus transmission over the period of the games, resulted in enhanced confidence from team members and no reports of positive serology.
Subject(s)
Anniversaries and Special Events , Sports , Zika Virus Infection/prevention & control , Brazil/epidemiology , Disease Outbreaks/prevention & control , Health Education , Humans , New Zealand , Risk Reduction Behavior , Zika Virus Infection/epidemiology , Zika Virus Infection/transmissionABSTRACT
Stochastic processes are highly relevant in research fields as different as neuroscience, economy, ecology, chemistry, and fundamental physics. However, due to their intrinsic unpredictability, stochastic mechanisms are very challenging for any kind of investigations and practical applications. Here we report the deliberate use of stochastic X-ray pulses in two-dimensional spectroscopy to the simultaneous mapping of unoccupied and occupied electronic states of atoms in a regime where the opacity and transparency properties of matter are subject to the incident intensity and photon energy. A readily transferable matrix formalism is presented to extract the electronic states from a dataset measured with the monitored input from a stochastic excitation source. The presented formalism enables investigations of the response of the electronic structure to irradiation with intense X-ray pulses while the time structure of the incident pulses is preserved.
ABSTRACT
We review our recent results on the implementation of picosecond (ps) X-ray absorption spectroscopy to probe the electronic and geometric structure of centres formed by photoexcitation of solar materials such as TiO2 polymorphs and inorganic Cs-based perovskites. The results show electron localization at Ti defects in TiO2 anatase and rutile and small hole polaron formation in the valence band of CsPbBr3, all within 80 ps. This method is promising for the study of the ultrafast time scales of such processes, especially with the advent of the Swiss X-ray Free Electron Laser (SwissFEL).
ABSTRACT
We present the main specifications of the newly constructed Swiss Free Electron Laser, SwissFEL, and explore its potential impact on ultrafast science. In light of recent achievements at current X-ray free electron lasers, we discuss the potential territory for new scientific breakthroughs offered by SwissFEL in Chemistry, Biology, and Materials Science, as well as nonlinear X-ray science.
ABSTRACT
The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of research. An important recent impetus comes from the ability to resolve ever faster temporal events, down to the attosecond time scale. Such a high temporal resolution now offers the possibility to unravel the most elementary quantum dynamics of both electrons and nuclei that participate in the complex process of charge transfer. This review covers recent research that addresses the following questions. Can we reconstruct the migration of charge across a molecule on the atomic length and electronic time scales? Can we use strong laser fields to control charge migration? Can we temporally resolve and understand intramolecular charge transfer in dissociative ionization of small molecules, in transition-metal complexes and in conjugated polymers? Can we tailor molecular systems towards specific charge-transfer processes? What are the time scales of the elementary steps of charge transfer in liquids and nanoparticles? Important new insights into each of these topics, obtained from state-of-the-art ultrafast spectroscopy and/or theoretical methods, are summarized in this review.
ABSTRACT
Hyponatraemia-induced rhabdomyolysis is a rare, but reported phenomenon, particularly in patients with chronic schizophrenia on depot antipsychotics prone to psychogenic polydipsia. To the best of our knowledge, there are no reported cases of hyponatraemia-induced rhabdomyolysis complicated by oligo-anuric acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). The initiation of CRRT is complicated in severe hyponatraemia, predominantly due to the need to avoid rapid changes in tonicity associated with rapid changes in sodium. We report a case of severe hyponatraemia (104â mmol/L) complicated by oligo-anuric rhabdomyolysis-induced AKI and our management of the renal prescription.
Subject(s)
Acute Kidney Injury/complications , Anuria/etiology , Hyponatremia/complications , Renal Replacement Therapy/methods , Rhabdomyolysis/complications , Acute Kidney Injury/diagnosis , Acute Kidney Injury/therapy , Anuria/diagnosis , Anuria/therapy , Humans , Male , Middle Aged , Rhabdomyolysis/diagnosis , Rhabdomyolysis/etiologyABSTRACT
BACKGROUND: There are numerous methods for adjusting measured concentrations of urinary biomarkers for hydration variation. Few studies use objective criteria to quantify the relative performance of these methods. Our aim was to compare the performance of existing methods for adjusting urinary biomarkers for hydration variation. METHODS: Creatinine, osmolality, excretion rate (ER), bodyweight adjusted ER (ERBW) and empirical analyte-specific urinary flow rate (UFR) adjustment methods on spot urinary concentrations of lead (Pb), cadmium (Cd), non-arsenobetaine arsenic (As(IMM)) and iodine (I) from the US National Health and Nutrition Examination Survey (NHANES) (2009-2010 and 2011-2012) were evaluated. The data were divided into a training dataset (n = 1,723) from which empirical adjustment coefficients were derived and a testing dataset (n = 428) on which quantification of the performance of the adjustment methods was done by calculating, primarily, the correlation of the adjusted parameter with UFR, with lower correlations indicating better performance and, secondarily, the correlation of the adjusted parameters with blood analyte concentrations (Pb and Cd), with higher correlations indicating better performance. RESULTS: Overall performance across analytes was better for Osmolality and UFR based methods. Excretion rate and ERBW consistently performed worse, often no better than unadjusted concentrations. CONCLUSIONS: Osmolality adjustment of urinary biomonitoring data provides for more robust adjustment than either creatinine based or ER or ERBW methods, the latter two of which tend to overcompensate for UFR. Modified UFR methods perform significantly better than all but osmolality in removing hydration variation, but depend on the accuracy of UFR calculations. Hydration adjustment performance is analyte-specific and further research is needed to establish a robust and consistent framework.
Subject(s)
Environmental Monitoring/methods , Urinalysis/methods , Adolescent , Adult , Aged , Aged, 80 and over , Arsenic/urine , Cadmium/blood , Cadmium/urine , Child , Creatinine/urine , Environmental Pollutants/urine , Female , Humans , Iodine/urine , Lead/blood , Lead/urine , Male , Middle Aged , Nutrition Surveys , Osmolar Concentration , Young AdultABSTRACT
Structural information of the different conformational states of the two prototypical light-sensitive membrane proteins, bacteriorhodopsin and rhodopsin, has been obtained in the past by X-ray cryo-crystallography and cryo-electron microscopy. However, these methods do not allow for the structure determination of most intermediate conformations. Recently, the potential of X-Ray Free Electron Lasers (X-FELs) for tracking the dynamics of light-triggered processes by pump-probe serial femtosecond crystallography has been demonstrated using 3D-micron-sized crystals. In addition, X-FELs provide new opportunities for protein 2D-crystal diffraction, which would allow to observe the course of conformational changes of membrane proteins in a close-to-physiological lipid bilayer environment. Here, we describe the strategies towards structural dynamic studies of retinal proteins at room temperature, using injector or fixed-target based serial femtosecond crystallography at X-FELs. Thanks to recent progress especially in sample delivery methods, serial crystallography is now also feasible at synchrotron X-ray sources, thus expanding the possibilities for time-resolved structure determination.
Subject(s)
Naval Medicine , Sports Medicine , Arrhythmias, Cardiac/diagnosis , Arrhythmias, Cardiac/therapy , Athletic Injuries/prevention & control , Attitude of Health Personnel , Attitude to Health , Back Pain/etiology , Back Pain/therapy , Diet , Early Diagnosis , Fractures, Stress/therapy , Humans , Nutritional Physiological Phenomena/physiology , Physical Conditioning, Human/physiology , Physical Therapy Modalities , Rib Fractures/therapy , Sports/physiology , Weight Loss/physiologyABSTRACT
Picosecond X-ray absorption spectroscopy (XAS) is used to investigate the electronic and structural dynamics initiated by plasmon excitation of 1.8 nm diameter Au nanoparticles (NPs) functionalised with 1-hexanethiol. We show that 100 ps after photoexcitation the transient XAS spectrum is consistent with an 8% expansion of the Au-Au bond length and a large increase in disorder associated with melting of the NPs. Recovery of the ground state occurs with a time constant of â¼1.8 ns, arising from thermalisation with the environment. Simulations reveal that the transient spectrum exhibits no signature of charge separation at 100 ps and allows us to estimate an upper limit for the quantum yield (QY) of this process to be <0.1.
ABSTRACT
Titanium dioxide (TiO2) is the most popular material for applications in solar-energy conversion and photocatalysis, both of which rely on the creation, transport, and trapping of charges (holes and electrons). The nature and lifetime of electron traps at room temperature have so far not been elucidated. Herein, we use picosecond X-ray absorption spectroscopy at the Ti K-edge and the Ru L3-edge to address this issue for photoexcited bare and N719-dye-sensitized anatase and amorphous TiO2 nanoparticles. Our results show that 100â ps after photoexcitation, the electrons are trapped deep in the defect-rich surface shell in the case of anatase TiO2, whereas they are inside the bulk in the case of amorphous TiO2. In the case of dye-sensitized anatase or amorphous TiO2, the electrons are trapped at the outer surface. Only two traps were identified in all cases, with lifetimes in the range of nanoseconds to tens of nanoseconds.
ABSTRACT
X-ray absorption spectra of fac-[ReBr(CO)3(bpy)] near the Re L3- and Br K-edges were measured in a steady-state mode as well as time-resolved at 630 ps after 355 nm laser pulse excitation. Relativistic spin-orbit time-dependent density functional theory (TD-DFT) calculations account well for the shape of the near-edge absorption (the â³white lineâ³) of the ground-state Re spectrum, assigning the lowest-lying transitions as core-to-ligand metal-to-ligand charge transfer from Re 2p(3/2) into predominantly π*(bpy) molecular orbitals (MOs) containing small 5d contributions, followed in energy by transitions into π* Re(CO)3 and delocalized σ*/π* MOs. Transitions gain their intensities from Re 5d and 6s participation in the target orbitals. The 5d character is distributed over many unoccupied MOs; the 5d contribution to any single empty MO does not exceed 29%. The Br K-edge spectrum is dominated by the ionization edge and multiple scattering features, the pre-edge electronic transitions being very weak. Time-resolved spectra measured upon formation of the lowest electronic excited state show changes characteristic of simultaneous Re and Br electronic depopulation: shifts of the Re and Br edges and the Re white line to higher energies and emergence of new intense pre-edge features that are attributed by TD-DFT to transitions from Re 2p(3/2) and Br 1s orbitals into a vacancy in the HOMO-1 created by electronic excitation. Experimental spectra together with quantum chemical calculations provide a direct evidence for a ReBr(CO)3 â bpy delocalized charge transfer character of the lowest excited state. Steady-state as well as time-resolved Re L3 spectra of [ReCl(CO)3(bpy)] and [Re(Etpy)(CO)3(bpy)](+) are very similar to those of the Br complex, in agreement with similar (TD) DFT calculated transition energies as well as delocalized excited-state spin densities and charge changes upon excitation.
Subject(s)
2,2'-Dipyridyl/chemistry , Bromides/chemistry , Carbon Monoxide/chemistry , Organometallic Compounds/chemistry , Quantum Theory , Rhenium/chemistry , Molecular Structure , Organometallic Compounds/chemical synthesis , X-Ray Absorption SpectroscopyABSTRACT
OBJECTIVE: To clarify the role of sports and exercise physicians as medical assessors. METHODS: Group discussion between senior doctors at a previous annual conference of the Australasian College of Sports Physicians, followed by further discussion between the authors. Clarification of the key requirements of insurers, and formulation of practical advice for those performing this work. RESULTS: Our expertise in performing medical assessments for the purpose of fitness to play sport is a transferable skill. It can also be used to provide medical assessments for injured workers. Our expertise in rehabilitation is also of value to insurers and other interested parties. CONCLUSION: The work is both challenging and rewarding, and can provide additional variety in the working week.