The effects of acute normobaric hypoxia on vestibular-evoked balance responses in humans.

BACKGROUND: Hypoxia influences standing balance and vestibular function. OBJECTIVE: The purpose here was to investigate the effect of hypoxia on the vestibular control of balance. METHODS: Twenty participants (10 males; 10 females) were tested over two days (normobaric hypoxia and normoxia). Participants stood on a force plate (head rotated leftward) and experienced random, continuous electrical vestibular stimulation (EVS) during trials of eyes open (EO) and closed (EC) at baseline (BL), after 5 (H1), 30 (H2) and 55-min (H3) of hypoxia, and 10-min into normoxic recovery (NR). Vestibular-evoked balance responses were quantified using cumulant density, coherence, and gain functions between EVS and anteroposterior forces. RESULTS: Oxyhemoglobin saturation, end-tidal oxygen and carbon dioxide decreased for H1-3 compared to BL; however, end-tidal carbon dioxide remained reduced at NR with EC (p≤0.003). EVS-AP force peak-to-peak amplitude was lower at H3 and NR than at BL (p≤0.01). At multiple frequencies, EVS-AP force coherence and gain estimates were lower at H3 and NR than BL for females; however, this was only observed for coherence for males. CONCLUSIONS: Overall, vestibular-evoked balance responses are blunted following normobaric hypoxia >30 min, which persists into NR and may contribute to the reported increases in postural sway.

Acupuncture-D" - Bilateral Pneumothoraces Following Dry Needling.

Presentation A 24-year-old newly graduated junior doctor presented to the emergency department with acute onset chest pain, haemoptysis and exertional dyspnoea following a dry needling session. Diagnosis Chest x-ray showed bilateral pneumothoraces, worse on the right side. Treatment The bilateral pneumothoraces were treated conservatively with supplemental oxygen initially. On the second day of admission, repeat chest x-ray demonstrated a worsening right sided pneumothorax. While vitally stable, the patient however had become increasingly dyspnoeic, and a needle aspiration was performed on the right side with good effect. Conclusion The anatomical location targeted along with the patients low-normal BMI makes her high-risk when considering the skin-to-pleura distance. Although the incidence of pneumothorax is low, it is imperative that we improve awareness both for the treating physician and the diagnosing clinician. We must begin to fill the distinct lack in available literature surrounding the potential adverse effects of dry needling.

A randomized clinical trial to evaluate the efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valve and atrial fibrillation or flutter: Rationale and design of the RIVER trial.

The efficacy and safety of rivaroxaban in patients with bioprosthetic mitral valves and atrial fibrillation or flutter remain uncertain. DESIGN: RIVER was an academic-led, multicenter, open-label, randomized, non-inferiority trial with blinded outcome adjudication that enrolled 1005 patients from 49 sites in Brazil. Patients with a bioprosthetic mitral valve and atrial fibrillation or flutter were randomly assigned (1:1) to rivaroxaban 20 mg once daily (15 mg in those with creatinine clearance <50 mL/min) or dose-adjusted warfarin (target international normalized ratio 2.0-30.); the follow-up period was 12 months. The primary outcome was a composite of all-cause mortality, stroke, transient ischemic attack, major bleeding, valve thrombosis, systemic embolism, or hospitalization for heart failure. Secondary outcomes included individual components of the primary composite outcome, bleeding events, and venous thromboembolism. SUMMARY: RIVER represents the largest trial specifically designed to assess the efficacy and safety of a direct oral anticoagulant in patients with bioprosthetic mitral valves and atrial fibrillation or flutter. The results of this trial can inform clinical practice and international guidelines.

Rivaroxaban in Patients with Atrial Fibrillation and a Bioprosthetic Mitral Valve.

BACKGROUND: The effects of rivaroxaban in patients with atrial fibrillation and a bioprosthetic mitral valve remain uncertain. METHODS: In this randomized trial, we compared rivaroxaban (20 mg once daily) with dose-adjusted warfarin (target international normalized ratio, 2.0 to 3.0) in patients with atrial fibrillation and a bioprosthetic mitral valve. The primary outcome was a composite of death, major cardiovascular events (stroke, transient ischemic attack, systemic embolism, valve thrombosis, or hospitalization for heart failure), or major bleeding at 12 months. RESULTS: A total of 1005 patients were enrolled at 49 sites in Brazil. A primary-outcome event occurred at a mean of 347.5 days in the rivaroxaban group and 340.1 days in the warfarin group (difference calculated as restricted mean survival time, 7.4 days; 95% confidence interval [CI], -1.4 to 16.3; P<0.001 for noninferiority). Death from cardiovascular causes or thromboembolic events occurred in 17 patients (3.4%) in the rivaroxaban group and in 26 (5.1%) in the warfarin group (hazard ratio, 0.65; 95% CI, 0.35 to 1.20). The incidence of stroke was 0.6% in the rivaroxaban group and 2.4% in the warfarin group (hazard ratio, 0.25; 95% CI, 0.07 to 0.88). Major bleeding occurred in 7 patients (1.4%) in the rivaroxaban group and in 13 (2.6%) in the warfarin group (hazard ratio, 0.54; 95% CI, 0.21 to 1.35). The frequency of other serious adverse events was similar in the two groups. CONCLUSIONS: In patients with atrial fibrillation and a bioprosthetic mitral valve, rivaroxaban was noninferior to warfarin with respect to the mean time until the primary outcome of death, major cardiovascular events, or major bleeding at 12 months. (Funded by PROADI-SUS and Bayer; RIVER ClinicalTrials.gov number, NCT02303795.).

Vancomycin area under the curve to minimum inhibitory concentration ratio predicting clinical outcome: a systematic review and meta-analysis with pooled sensitivity and specificity.

BACKGROUND: Vancomycin is a first-line antibiotic for methicillin-resistant Staphylococcus aureus infections or other Gram-positive infections. The area under the curve (AUC) to minimum inhibitory concentration (MIC) ratio is proposed as a therapeutic drug-monitoring parameter. How well clinical efficacy is predicted by this measure has not been established. OBJECTIVE: Determine the test performance characteristics (TPC) of AUC:MIC of vancomycin for prediction of positive outcome. DATA SOURCES: PubMed and Ovid Medline (1946 to 2018) and EMBASE (1974 to 2018). Study Eligibility Criteria and Participants: Studies of patients treated with vancomycin for any type of infection in peer reviewed publications. All patient populations were included. INTERVENTIONS: Vancomycin AUC:MIC or AUC was related to patient clinical outcome. METHODS: Searches of medical databases using relevant terms were performed. Screening, study reviewing, data extracting and assessing data quality was performed independently by two reviewers. Studies were stratified by type of primary outcome for calculation of pooled sensitivity, specificity and construction of hierarchical summary receiver operating characteristic (HSROC) curves. RESULTS: Nineteen studies including 1699 patients were meta-analysed. Pooled sensitivity and specificity were 0.77 (95% CI 0.67-0.84) and 0.62 (95% CI 0.53-0.71) respectively for the seven studies with primary outcome of mortality and 0.65 (95% CI 0.53-0.75), 0.58 (95% CI 0.48-0.67) for studies with composite or clinical cure outcome (n = 12). HSROC curves suggested considerable heterogeneity. An additional 11 studies were described but could not be included for meta-analysis because data were not available. The majority of these studies (9/11) failed to demonstrate a relationship between AUC:MIC and positive clinical outcome. CONCLUSIONS: Vancomycin AUC:MIC performance was modest and inconsistent. Analysis was limited by studies without sufficient data; therefore, meta-analytic results may overestimate TPC values. Given this, as well as the lack of standardization of methods, widespread adoption of AUC:MIC as the preferred vancomycin monitoring parameter may be premature.

Phylogenetic structure of Holbrookia lacerata (Cope 1880) (Squamata: Phrynosomatidae): one species or two?

Species delimitation attempts to match species-level taxonomy with actual evolutionary lineages. Such taxonomic conclusions are typically, but not always, based on patterns of congruence across multiple data sources and methods of analyses. Here, we use this pluralistic approach to species delimitation to help resolve uncertainty in species boundaries of phrynosomatid sand lizards of the genus Holbrookia. Specifically, the Spot-tailed Earless Lizard (H. lacerata) was historically divided into a northern (H. l. lacerata) and southern (H. l. subcaudalis) subspecies based on differences in morphology and allopatry, but no research has been conducted evaluating genetic differences between these taxa. In this study, patterns in sequence data derived from two genes, one nuclear and one mitochondrial, for 66 individuals sampled across 18 counties in Texas revealed three strongly supported, reciprocally monophyletic lineages, each comprised of individuals from a single geographic region. Distinct genetic variation evident across two of these regions corresponds with differences in morphology, differences in environmental niche, and lines up with the presumed geographic barrier, the Balcones Escarpment, which is the historical subspecies boundary. The combined evidence from genetics, morphology and environmental niche is sufficient to consider these subspecies as distinct species with the lizards north of the Balcones Escarpment retaining the name Holbrookia lacerata, and those south of the Balcones Escarpment being designated as Holbrookia subcaudalis.

Clinical outcomes in patients admitted to a hospitalist service exposed to an antimicrobial stewardship program - a retrospective matched cohort study.

Background: Given global issues with antimicrobial resistance and a need to optimize antimicrobial usage, antimicrobial stewardship (AS) programs are becoming a necessary component of hospitals and are increasingly mandated worldwide. It is important to evaluate these programs with respect to relevant clinical outcomes. Methods: An AS program with a prospective audit and feedback service (PAF) of antimicrobial usage was initiated May 11, 2015 at our tertiary care center, for patients admitted under the hospitalist service. We conducted a retrospective matched cohort study. Patients assessed during the first year of this PAF were considered to be the exposed cohort and were compared to unexposed controls matched on gender, age and infectious diagnosis selected from patients who had been admitted under the hospitalist service prior to initiation of the PAF. Descriptive analysis was completed and a multivariate conditional logistic regression was performed to analyze differences between the exposed and control groups in terms of a composite endpoint of 30 day mortality, 30 day post hospital discharge mortality and hospital re-admission. Results: A total of 348 patients were assessed and received PAF suggestions during the first year were compared to 827 matched control patients who did not receive PAF suggestions. Of 707 PAF suggestions made, the most common was to stop an antimicrobial (23%). A significantly lower (20.7% vs 28.8%, p = 0.008) composite endpoint was found in the group exposed to the PAF (OR 0.71 95%CI 0.52-0.97). This difference persisted when only patients with PAF suggestions that were completely or partially accepted were considered (18.6% vs 28.5%, p = 0.001) but was no longer significant when patients who had their ASP suggestions declined were analyzed (30.2% vs 26.7%, p = 0.610). Conclusions: In this retrospective cohort study, patient admissions in which PAF recommendations were accepted had better clinical outcomes than matched historical controls managed in the absence of this AS service.

Rationale and development of a business case for antimicrobial stewardship programs in acute care hospital settings.

Background: Antimicrobial stewardship programs (ASPs) have been shown to reduce inappropriate antimicrobial use and its consequences. However, these programs lack legislative requirements in many places and it can be difficult to determine what human resources are required for these programs and how to create a business case to present to hospital administrators for program funding. The objectives of the current paper were to review legislative requirements and outline human resource requirements for ASPs, and to create a base business case for ASPs. Methods: A working group of antimicrobial stewardship experts from across Canada met to discuss the necessary components for creation of a business case for antimicrobial stewardship. A narrative review of the literature of the regulatory requirements and human resource recommendations for ASPs was conducted. Informed by the review and using a consensus decision-making process, the expert working group developed human resource recommendations based on a 1000 bed acute care health care facility in Canada. A spreadsheet based business case model for ASPs was also created. Results: Legislative and /or regulatory requirements for ASPs were found in 2 countries and one state jurisdiction. The literature review and consensus development process recommended the following minimum human resources complement: 1 physician, 3 pharmacists, 0.5 program administrative and coordination support, and 0.4 data analyst support as full time equivalents (FTEs) per 1000 acute care beds. Necessary components for the business case model, including the human resource requirements, were determined to create a spreadsheet based model. Conclusions: There is evidence to support the negative outcomes of inappropriate antimicrobial use as well as the benefits of ASPs. Legislative and /or regulatory requirements for ASPs are not common. The available evidence for human resource recommendations for ASPs using a narrative review process was examined and a base business case modelling scenario was created. As regulatory requirements for ASPs increase, it will be necessary to create accurate business cases for ASPs in order to obtain the necessary funding to render these programs successful.

Nickel(ii) pincer complexes demonstrate that the remote substituent controls catalytic carbon dioxide reduction.

The first example of a CNC pincer ligand with a central pyridinol ligand is reported in a nickel(ii) complex. This metal complex can be protonated or deprotonated reversibly in situ to switch on or off the photocatalytic performance towards CO2 reduction. The O- substituent appears essential for catalysis.

Thermodynamic Acidity Studies of 6,6'-Dihydroxy-2,2'-bipyridine: A Combined Experimental and Computational Approach.

The organic ligand 6,6'-dihydroxy-2,2'-bipyridine (6,6'-dhbp) is frequently used to bind transition metals in order to form catalysts for many organic and inorganic transformations. 6,6'-dhbp exists in two tautomeric forms, the pyridinol tautomer and the amide (lactam) tautomer with each tautomer having two rotational conformers: cis or trans. Only the cis-pyridinol tautomer has the proper configuration to bind transition metals. The pendant OH (or O- groups when deprotonated) in 6,6'-dhbp typically do not bind the metal when forming the metal catalyst but can facilitate the proton transfer steps in the catalysis process. Electronic structure calculations were used to predict the stability of all possible isomers (including conformers and protonation states) in the gas phase and aqueous solution. These results have been compared to experimental data including UV-vis and NMR spectra as a function of pH. The pKa values for the 6,6'-dhbp ligand in the -2 to +2 structures were predicted, and these ligands show different behavior in the gas phase versus in aqueous solution.

Ruthenium (II) and Iridium (III) Complexes of N-Heterocyclic Carbene and Pyridinol Derived Bidentate Chelates: Synthesis, Characterization, and Reactivity.

We report the synthesis and characterization of new ruthenium(II) and iridium(III) complexes of a new bidentate chelate, NHCR'-pyOR (OR = OMe, OtBu, OH and R' = Me, Et). Synthesis and characterization studies were done on the following compounds: four ligand precursors (1-4); two silver complexes of these NHCR'-pyOR ligands (5-7); six ruthenium complexes of the type [η6-(p-cymene)Ru(NHCR'-pyOR)Cl]X with R' = Me, Et and R = Me, tBu, H and X = OTf-, PF6- and PO2F2- (8-13); and two iridium complexes, [Cp*Ir(NHCMe-pyOtBu)Cl]PF6 (14) and [Cp*Ir(NHCMe-pyOH)Cl]PO2F2 (15). The complexes are air stable and were isolated in moderate yield. However, for the PF6- salts, hydrolysis of the PF6- counter anion to PO2F2- during t-butyl ether deprotection was observed. Most of the complexes were characterized by 1H and 13C-NMR, MS, IR, and X-ray diffraction. The ruthenium complexes [η6-(p-cymene)Ru(NHCMe-pyOR)Cl]OTf (R = Me (8) and tBu (9)) were tested for their ability to accelerate CO2 hydrogenation and formic acid dehydrogenation. However, our studies show that the complexes transform during the reaction and these complexes are best thought of as pre-catalysts.

Terapia anticoagulante no tromboembolismo venoso / Anticoagulant therapy in venous thromboembolism

Introdução: O tromboembolismo venoso (TEV), incluindo a embolia pulmonar (EP) e a trombose venosa profunda (TVP), é a terceira causa de mortalidade em todo o mundo. O diagnóstico ainda é subestimado nas emergências. Os fatores desencadeantes são bem definidos, o que auxilia a estratificação de risco e o diagnóstico de TEV provocada ou não e influenciará muito o tempo de tratamento. O aumento do ventrículo direito e de marcadores biológicos tem desempenhado grande papel no prognóstico. O quadro clínico é bem definido e tem várias ferramentas, tanto para o diagnóstico como para a estratificação de risco, tais como os critérios de Wells e de Genebra, além de outros. Os exames complementares atualmente estão bem definidos, com a angiografia pulmonar sendo o padrão de referência; porém, com a melhora da tecnologia e a alta sensibilidade e especificidade, a angiotomografia computadorizada ocupou um lugar de destaque. Outros exames ainda são importantes em várias situações, como o D-dímero e outros biomarcadores, a radiografia de tórax, a cintilografia de perfusão/ventilação, eletrocardiograma, ecocardiografia e doppler venoso de membros inferiores. Método: Neste artigo, revisamos aspectos básicos de epidemiologia, diagnóstico e estratificação de risco. O foco principal foi o tratamento com a terapia anticoagulante, sobre a qual revisamos os seis estudos clínicos descritos entre 2009 e 2013, que abordam os novos anticoagulantes orais, hoje denominados anticoagulantes orais diretos. Esses estudos têm desenhos diferentes, com três deles começando com anticoagulantes orais desde o início do quadro agudo de TVP e EP (rivaroxabana e edoxabana). Os outros três iniciaram com enoxaparina e varfarina durante os primeiros dias e depois seguiram com a medicação do grupo em avaliação (dabigatrana e apixabana). Resultados: Nos estudos analisados, todos obtiveram uma redução (valor de p de não inferioridade) dos eventos de recorrência de TEV com relação à varfarina. Nos desfechos de segurança, definidos como sangramento fatal, clinicamente relevante e outros, os novos anticoagulantes orais obtiveram uma diminuição significativa. Conclusões: Os anticoagulantes orais diretos tiveram redução da recorrência de eventos tromboembólicos (periférico e pulmonar), com redução significativa dos índices de sangramentos fatais ou não. A segurança coloca-os como opção segura e eficaz para o tratamento desses pacientes com risco baixo e intermediário de TEV

Introduction: Venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), is the third leading cause of death worldwide. The diagnosis is still underestimated in emergencies. The triggering factors are well defined, which assists in the stratification of risk and in the diagnosis of VTE, whether provoked or not, and will greatly influence the treatment time. Increased right ventricle and biological markers have played a large role in the prognosis. The clinical features are well defined, and there are various tools for diagnosis and for risk stratification, such as the Wells and Geneva criteria, among others. Complementary exams are now well defined, with pulmonary angiography being the gold standard, but with improved technology and high sensitivity and specificity, computerized angiotomography has played a prominent role. Other exams are still important in certain situations, such as D-dimer and other biomarkers, chest radiography, perfusion/ventilation scintigraphy, electrocardiogram, echocardiography, and lower limb venous Doppler. Method: In this article we review basic aspects of epidemiology, diagnosis, and risk stratification. The main focus was treatment with anticoagulant therapy, under which we reviewed the six clinical studies described between 2009 and 2013 that address the new oral anticoagulants, now called direct oral anticoagulants. These studies have different designs; three of them start with oral anticoagulants from the onset of acute DVT and PE (rivaroxaban and edoxaban), and the other three start with enoxaparin and warfarin during the first days and then with the medication of the study group being evaluated (dabigatran and apixaban). Results: In the analyzed studies, all of them obtained a reduction (non-inferiority p-value) of the events of VTE recurrence in relation to warfarin. In the safety outcomes, defined as clinically relevant fatal bleeding and others, the new oral anticoagulants achieved a significant reduction. Conclusions: Direct oral anticoagulants had a reduction in the recurrence of thromboembolic events (peripheral and pulmonary), with a significant reduction in rates of fatal or non-fatal bleeding. Their safety makes them a reliable and effective option for the treatment of these patients, with low and intermediate risk of VTE

What side effects are problematic for patients prescribed antipsychotic medication? The Maudsley Side Effects (MSE) measure for antipsychotic medication.

BACKGROUND: Capturing service users' perspectives can highlight additional and different concerns to those of clinicians, but there are no up to date, self-report psychometrically sound measures of side effects of antipsychotic medications. Aim To develop a psychometrically sound measure to identify antipsychotic side effects important to service users, the Maudsley Side Effects (MSE) measure. METHOD: An initial item bank was subjected to a Delphi exercise (n = 9) with psychiatrists and pharmacists, followed by service user focus groups and expert panels (n = 15) to determine item relevance and language. Feasibility and comprehensive psychometric properties were established in two samples (N43 and N50). We investigated whether we could predict the three most important side effects for individuals from their frequency, severity and life impact. RESULTS: MSE is a 53-item measure with good reliability and validity. Poorer mental and physical health, but not psychotic symptoms, was related to side-effect burden. Seventy-nine percent of items were chosen as one of the three most important effects. Severity, impact and distress only predicted 'putting on weight' which was more distressing, more severe and had more life impact in those for whom it was most important. CONCLUSIONS: MSE is a self-report questionnaire that identifies reliably the side-effect burden as experienced by patients. Identifying key side effects important to patients can act as a starting point for joint decision making on the type and the dose of medication.

Iridium and Ruthenium Complexes of N-Heterocyclic Carbene- and Pyridinol-Derived Chelates as Catalysts for Aqueous Carbon Dioxide Hydrogenation and Formic Acid Dehydrogenation: The Role of the Alkali Metal.

Hydrogenation reactions can be used to store energy in chemical bonds, and if these reactions are reversible, that energy can be released on demand. Some of the most effective transition metal catalysts for CO2 hydrogenation have featured pyridin-2-ol-based ligands (e.g., 6,6'-dihydroxybipyridine (6,6'-dhbp)) for both their proton-responsive features and for metal-ligand bifunctional catalysis. We aimed to compare bidentate pyridin-2-ol based ligands with a new scaffold featuring an N-heterocyclic carbene (NHC) bound to pyridin-2-ol. Toward this aim, we have synthesized a series of [Cp*Ir(NHC-pyOR)Cl]OTf complexes where R = t Bu (1), H (2), or Me (3). For comparison, we tested analogous bipy-derived iridium complexes as catalysts, specifically [Cp*Ir(6,6'-dxbp)Cl]OTf, where x = hydroxy (4Ir ) or methoxy (5Ir ); 4Ir was reported previously, but 5Ir is new. The analogous ruthenium complexes were also tested using [(η6-cymene)Ru(6,6'-dxbp)Cl]OTf, where x = hydroxy (4Ru ) or methoxy (5Ru ); 4Ru and 5Ru were both reported previously. All new complexes were fully characterized by spectroscopic and analytical methods and by single-crystal X-ray diffraction for 1, 2, 3, 5Ir , and for two [Ag(NHC-pyOR)2]OTf complexes 6 (R = t Bu) and 7 (R = Me). The aqueous catalytic studies of both CO2 hydrogenation and formic acid dehydrogenation were performed with catalysts 1-5. In general, NHC-pyOR complexes 1-3 were modest precatalysts for both reactions. NHC complexes 1-3 all underwent transformations under basic CO2 hydrogenation conditions, and for 3, we trapped a product of its transformation, 3SP , which we characterized crystallographically. For CO2 hydrogenation with base and dxbp-based catalysts, we observed that x = hydroxy (4Ir ) is 5-8 times more active than x = methoxy (5Ir ). Notably, ruthenium complex 4Ru showed 95% of the activity of 4Ir . For formic acid dehydrogenation, the trends were quite different with catalytic activity showing 4Ir ≫ 4Ru and 4Ir ≈ 5Ir . Secondary coordination sphere effects are important under basic hydrogenation conditions where the OH groups of 6,6'-dhbp are deprotonated and alkali metals can bind and help to activate CO2. Computational DFT studies have confirmed these trends and have been used to study the mechanisms of both CO2 hydrogenation and formic acid dehydrogenation.

Improved outcomes for inborn babies with uncomplicated gastroschisis.

INTRODUCTION: Gastroschisis (GS) is a common abdominal wall defect necessitating neonatal surgery and intensive care. We hypothesized that inborn patients had improved outcomes compared to patients born at an outside hospital (outborn) and transferred for definitive treatment. METHODS: A single center, retrospective chart review at a pediatric tertiary care center was performed from 2010 to 2015. All patients whose primary surgical treatment of GS was performed at this center were included. We compared patients delivered within our center (inborn) to patients delivered outside of our center and transferred for surgical care (outborn). Babies with complicated gastroschisis were excluded. RESULTS: During the study period 79 patients with GS were identified. Of these, 53 were inborn and 26 were outborn. Sixteen patients were excluded for complicated GS. The rate of complicated GS was higher in the outborn group (32%) compared to the inborn population (11%) (p=0.03). Duration of stay, readmission rate and time on TPN were all significantly decreased for inborn patients, while time to definitive closure was similar. Mortality was 0% for both inborn and outborn patients. CONCLUSION: Patients with uncomplicated GS seem to benefit from delivery with immediate pediatric surgical care available eliminating the need for transfer. LEVEL OF EVIDENCE: III.

Studies of the pathways open to copper water oxidation catalysts containing proximal hydroxy groups during basic electrocatalysis.

Water oxidation can lead to a sustainable source of energy, but for water oxidation catalysts to be economical they must use earth abundant metals. We report here 2:1 6,6'-dihydroxybipyridine (6,6'-dhbp)/copper complexes that are capable of electrocatalytic water oxidation in aqueous base (pH = 10-14). Two crystal structures of the complex that contains 6,6'-dhbp and copper(II) in a ratio of 2:1 (complex 1) are presented at different protonation states. The thermodynamic acid dissociation constants were measured for complex 1, and these show that the complex is fully deprotonated above pH = 8.3 (i.e., under water oxidation conditions). CW-EPR, ENDOR, and HYSCORE spectroscopy confirmed that the 6,6'-dhbp ligand is bound to the copper ion over a wide pH range which shows how pH influences precatalyst structure. Additional copper(II) complexes were synthesized from the ligands 4,4'-dhbp (complex 2) and 6,6'-dimethoxybipyridine (complexes 3 and 4). A zinc complex of 6,6'-dhbp was also synthesized (complex 5). Crystal structures are reported for 1 (in two protonation states), 3, 4, and 5. Water oxidation studies using several of the above compounds (1, 2, 4, and 5) at pH = 12.6 have illustrated that both copper and proximal OH groups are necessary for water oxidation at a low overpotential. Our most active catalyst 1 was found to have an overpotential of 477 mV for water oxidation at a moderate rate of kcat = 0.356 s(-1) with a competing irreversible oxidation event at a rate of 1.082 s(-1). Furthermore, our combined work supports previous observations in which OH/O(-) groups on the bipyridine rings can hydrogen bond with metal bound substrate, support unusual binding modes, and potentially facilitate proton coupled electron transfer.

Motor unit properties from three synergistic muscles during ramp isometric elbow extensions.

Many tasks require synergistic activation of muscles that possess different architectural, mechanical, and neural control properties. However, investigations of the motor unit (MU) mechanisms which modulate force are mostly restricted to individual muscles and low forces. To explore the pattern of MU recruitment and discharge behavior among three elbow extensors (lateral and long heads of the triceps brachii, and anconeus) during ramp isometric contractions, recruitment thresholds of 77 MUs in five young men were determined and corresponding MU discharge rates were tracked in 1-s epochs over forces ranging from 0 to 75 % of maximal voluntary isometric force (MVC). Across all forces, MUs in the lateral head discharged at higher rates than those in the anconeus (p < 0.001, Δ = 0.23). When all MUs were considered, recruitment thresholds in the long head of the triceps brachii were higher than the lateral head (p < 0.05, Δ = 0.70) with a trend (p = 0.08, Δ = 0.48) for higher recruitment thresholds in the long head compared with the anconeus. Together, these data indicate a potential mechanical disadvantage of the long head of the triceps brachii at 0° shoulder flexion. However, among low-threshold MUs (<10 % MVC), recruitment thresholds were lower in the anconeus than in both heads of the triceps brachii consistent with the expected twitch contractile and fiber type differences among these muscles. These findings illustrate the importance of considering synergistic relations among muscles used for a coordinated task, and the sensitivity of synergies to muscle architectural, mechanical, and possibly specific synaptic input factors.

Screening and management of renal disease in human immunodeficiency virus-infected patients in Australia.

BACKGROUND: Renal disease has become one of the most important comorbidities observed in the human immunodeficiency virus (HIV)-infected patient cohort. Data are lacking on the current screening and management of renal disease in patients with HIV. We evaluated HIV-infected Australian adults in primary care to determine current practices. METHODS: This prospective, multicentre observational study included two rounds of data collection; the first was followed by an educational programme. Outcomes included screening for renal disease; management of risk factors for kidney disease and other comorbidities associated with renal disease. RESULTS: Fifty-three general practitioners participated with 733 patients enrolled. Most were male (94%); almost 40% were 41-50 years of age, and 6% and 84% were receiving antiretroviral therapy. Comorbidities were common; 19% had hypertension, 5% were diabetic, 32% were dyslipidaemic, and 40% were smokers. Estimated glomerular filtration rate was commonly measured in both rounds of data collection (96% vs 95%). Proteinuria was assessed less frequently; this improved after education (48% vs 71%). Almost 10% of patients tested had proteinuria on urinalysis. Of the 45 patients (6%) with renal impairment (estimated glomerular filtration rate <60 mL/min), none was referred for assessment by a renal specialist. CONCLUSIONS: This large observational study provides important information on renal disease in HIV-infected patients, an area with a paucity of clinical data. Current screening and management practices fall short of suggested guidelines. Failure to refer patients to specialists is a major deficiency. Improvements with education suggest the need to promote awareness of guidelines in primary care doctors.