Chemically-resolved determination of hydrogenated graphene-substrate interaction

Functionalization of graphene on Ir(111) is a promising route to modify graphene by chemical means in a controlled fashion at the nanoscale. Yet, the nature of such functionalized sp3 nanodots remains unknown. Density functional theory (DFT) calculations alone cannot differentiate between two plausible structures, namely true graphane and substrate stabilized graphane-like nanodots. These two structures, however, interact dramatically differently with the underlying substrate. Discriminating which type of nanodots forms on the surface is thus of paramount importance for the applications of such prepared nanostructures. By comparing X-ray standing wave measurements against theoretical model structures obtained by DFT calculations we are able to exclude the formation of true graphane nanodots and clearly show the formation graphane-like nanodots.

A Practical Guide to Surface Kinetic Monte Carlo Simulations

This review article is intended as a practical guide for newcomers to the field of kinetic Monte Carlo (KMC) simulations, and specifically to lattice KMC simulations as prevalently used for surface and interface applications. We will provide worked out examples using the kmos code, where we highlight the central approximations made in implementing a KMC model as well as possible pitfalls. This includes the mapping of the problem onto a lattice and the derivation of rate constant expressions for various elementary processes. Example KMC models will be presented within the application areas surface diffusion, crystal growth and heterogeneous catalysis, covering both transient and steady-state kinetics as well as the preparation of various initial states of the system. We highlight the sensitivity of KMC models to the elementary processes included, as well as to possible errors in the rate constants. For catalysis models in particular, a recurrent challenge is the occurrence of processes at very different timescales, e.g., fast diffusion processes and slow chemical reactions. We demonstrate how to overcome this timescale disparity problem using recently developed acceleration algorithms. Finally, we will discuss how to account for lateral interactions between the species adsorbed to the lattice, which can play an important role in all application areas covered here.

Hydrogen interaction with graphene on Ir(1 1 1): a combined intercalation and functionalization study

We demonstrate a procedure for obtaining a H-intercalated graphene layer that is found to be chemically decoupled from the underlying metal substrate. Using high-resolution x-ray photoelectron spectroscopy and scanning tunneling microscopy techniques, we reveal that the hydrogen intercalated graphene is p-doped by about 0.28 eV, but also identify structures of interfacial hydrogen. Furthermore, we investigate the reactivity of the decoupled layer towards atomic hydrogen and vibrationally excited molecular hydrogen and compare these results to the case of non-intercalated graphene. We find distinct differences between the two. Finally, we discuss the possibility to form graphane clusters on an iridium substrate by combined intercalation and H atom exposure experiments.

General practitioners' and nurses' views on medication reviews and potentially inappropriate medicines in elderly patients - a qualitative study of reports by educating pharmacists

OBJECTIVE

The aim with this study was to understand more about how general practitioners (GPs) and nurses in primary care experience their work with medication reviews in elderly patients.

DESIGN

This qualitative study was nested within a cluster randomised trial and analysed narrative and unstructured diaries written by two pharmacists who performed academic detailing, i.e. educational outreach visits in primary care. The educational sessions dealt with potentially inappropriate medicines, and stimulated interprofessional dialogue in relation to medication reviews. The purpose of the diaries was to document and structure the pedagogical process of academic detailing and contained quotes from 194 GP and 113 nurse participants in the sessions, and the pharmacists' reflections. The data was explored using thematic analysis.

SETTING

Thirty-three primary care practices in Stockholm, Sweden.

SUBJECTS

GPs and nurses working in primary care.

MAIN OUTCOME MEASURES

Thematic descriptions of academic detailing by pharmacists.

RESULTS

Five themes were identified: 1) Complexity in 3 'P': patients, pharmacotherapy, and primary care; 2) What, when, who? Clash between GPs' and nurses' experiences and guidelines; 3) Real-world problems and less-than-ideal solutions; 4) Eureka? Experiences with different steps during a medication review; and 5) Threats to GP autonomy.

CONCLUSION

GPs and nurses should participate in the construction and release of guidelines in order to increase their usability in clinical practice. Future research should analyse if alternative strategies such as condensed medical reviews and feedback on prescribing are easier to implement in primary care. Key points Complex medication reviews have been introduced on a large scale in Swedish primary care, but knowledge on GPs' and nurses' views on such reviews is lacking. In the context of primary care alternative strategies such as condensed medication reviews and feedback on prescribing may be more applicable than medication reviews according to guidelines. GPs and nurses should make contributions to the development of guidelines on medication reviews in order to increase their usability in clinical practice.

Assessment of mean-field microkinetic models for CO methanation on stepped metal surfaces using accelerated kinetic Monte Carlo

First-principles screening studies aimed at predicting the catalytic activity of transition metal (TM) catalysts have traditionally been based on mean-field (MF) microkinetic models, which neglect the effect of spatial correlations in the adsorbate layer. Here we critically assess the accuracy of such models for the specific case of CO methanation over stepped metals by comparing to spatially resolved kinetic Monte Carlo (kMC) simulations. We find that the typical low diffusion barriers offered by metal surfaces can be significantly increased at step sites, which results in persisting correlations in the adsorbate layer. As a consequence, MF models may overestimate the catalytic activity of TM catalysts by several orders of magnitude. The potential higher accuracy of kMC models comes at a higher computational cost, which can be especially challenging for surface reactions on metals due to a large disparity in the time scales of different processes. In order to overcome this issue, we implement and test a recently developed algorithm for achieving temporal acceleration of kMC simulations. While the algorithm overall performs quite well, we identify some challenging cases which may lead to a breakdown of acceleration algorithms and discuss possible directions for future algorithm development.

Mitochondria, glycogen, and lipid droplets in skeletal muscle during testosterone treatment and strength training: a randomized, double-blinded, placebo-controlled trial

Low testosterone levels in aging men are associated with insulin resistance. Mitochondrial dysfunction, changes in glycogen metabolism, and lipid accumulation are linked to insulin resistance in skeletal muscle. In this randomized, double-blinded, placebo-controlled study, we investigated the effects of six-month testosterone replacement therapy (TRT) and strength training (ST) on mitochondrial, glycogen, and lipid droplet (LD) content in skeletal muscle of aging men with subnormal bioavailable testosterone (BioT) levels. Mitochondrial, glycogen, and LD volume fractions in muscle biopsies were estimated by transmission electron microscopy. Insulin sensitivity (insulin-stimulated Rd) and body composition were assessed by euglycemic-hyperinsulinemic clamp and dual X-ray absorptiometry, respectively. TRT significantly increased total testosterone levels, BioT, and lean body mass (LBM) (p < 0.05), whereas percent body fat decreased (p < 0.05), and insulin sensitivity was unchanged. Baseline mitochondrial volume fraction correlated inversely with percent body fat (ρ = -0.43; p = 0.003). Δ-mitochondrial fraction correlated positively with Δ-total testosterone (ρ = 0.70; p = 0.02), and Δ-glycogen fraction correlated inversely with Δ-LBM (ρ = -0.83; p = 0.002) during six-month TRT, but no significant changes were observed in mitochondrial, glycogen, and LD volume fractions during TRT and ST. In conclusion, in this exploratory small-scale study, the beneficial effects of six-month TRT on total testosterone, LBM, and percent body fat were not followed by significant changes in fractions of mitochondria, glycogen, or lipid in skeletal muscle of aging men with lowered testosterone levels. Six-month ST or combined three-month ST+TRT did not change intramyocellular mitochondria, glycogen, and LD fractions compared to placebo. However, further studies with a larger sample size are needed.

Ambient pressure phase transitions over Ir(1 1 1): at the onset of CO oxidation

In this study we report on the adsorbate structures on an Ir(1 1 1) surface during the phase transition from the inactive to the active state during CO oxidation. The CO oxidation over Pt(1 1 1) is used as a reference case. Where Pt(1 1 1) either is inactive and CO covered or active and O covered, Ir(1 1 1) exhibits a transition state with co-existing chemisorbed O and CO. The observed structural differences are explained in terms of DFT-calculated adsorption energies. For Pt(1 1 1) the repulsive CO-O interaction makes co-existing chemisorbed CO and O unfavourable, while for Ir(1 1 1) the stronger O and CO adsorption allows for overcoming the repulsive interaction. At the onset of CO oxidation over Ir(1 1 1), a CO structure containing defects forms, which enables O₂ to dissociatively adsorb on the Ir(1 1 1) surface, thus enabling the CO oxidation reaction. At the mass transfer limit, the Ir(1 1 1) surface is covered by a chemisorbed O structure with defects; hence, the active surface is predominately chemisorbed O covered at a total pressure of 0.5 mbar and no oxide formation is observed.

Educational intervention on medication reviews aiming to reduce acute healthcare consumption in elderly patients with potentially inappropriate medicines-A pragmatic open-label cluster-randomized controlled trial in primary care

PURPOSE

Potentially inappropriate medicines (PIMs) may cause 10% of unplanned admissions in elderly people. We performed an educational intervention in primary care to reduce acute health care consumption and PIMs through the promotion of medication reviews (MRs) in elderly patients.

METHODS

This cluster-randomized controlled trial was conducted in the context of an official campaign promoting rational drug use in elderly people. Sixty-nine primary health care practices with 119,910 patients aged older than or equal to 65 were randomized, with 1 dropout in the intervention group. The intervention consisted of educational outreach visits with feedback on prescribing and the development of a working procedure on MRs. Follow-up was 9 months. Outcomes were assessed in an administrative health care database. The combined primary outcome was unplanned hospital admission and/or emergency department visit. Secondary outcomes were among other PIMs and rates of MRs. The risk differences in outcomes between intervention and control group were estimated by using regression models.

RESULTS

During follow-up, 22.8% of patients in the intervention and 22.0% in the control group were admitted unplanned to hospital and/or experienced at least 1 emergency department (nonsignificant risk difference 0.8%, 95% CI -0.7% to 2.4%). There were no significant differences regarding secondary outcomes such as PIMs or MRs.

CONCLUSIONS

No changes were seen in acute health care consumption, PIMs, and MRs in elderly patients after an educational intervention in primary care. The reasons for the lack of effect could be a suboptimal intervention, limitations in outcome measures, and the use of administrative data to monitor outcomes.

MR spectroscopy of hepatic fat and adiponectin and leptin levels during testosterone therapy in type 2 diabetes: a randomized, double-blinded, placebo-controlled trial

BACKGROUND

Men with type 2 diabetes mellitus (T2D) often have lowered testosterone levels and an increased risk of cardiovascular disease (CVD). Ectopic fat increases the risk of CVD, whereas subcutaneous gluteofemoral fat protects against CVD and has a beneficial adipokine-secreting profile.

HYPOTHESIS

Testosterone replacement therapy (TRT) may reduce the content of ectopic fat and improve the adipokine profile in men with T2D.

DESIGN AND METHODS

A randomized, double-blinded, placebo-controlled study in 39 men aged 50-70 years with T2D and bioavailable testosterone levels <7.3 nmol/L. Patients were randomized to TRT (n = 20) or placebo gel (n = 19) for 24 weeks. Thigh subcutaneous fat area (TFA, %fat of total thigh volume), subcutaneous abdominal adipose tissue (SAT, % fat of total abdominal volume) and visceral adipose tissue (VAT, % fat of total abdominal volume) were measured by magnetic resonance (MR) imaging. Hepatic fat content was estimated by single-voxel MR spectroscopy. Adiponectin and leptin levels were measured by in-house immunofluorometric assay. Coefficients (b) represent the placebo-controlled mean effect of intervention.

RESULTS

TFA (b = -3.3 percentage points (pp), P = 0.009), SAT (b = -3.0 pp, P = 0.006), levels of adiponectin (b = -0.4 mg/L, P = 0.045), leptin (b = -4.3 µg/mL, P < 0.001), leptin:adiponectin ratio (b = -0.53, P = 0.001) and HDL cholesterol (b = -0.11 mmol/L, P = 0.009) decreased during TRT compared with placebo. Hepatic fat content and VAT were unchanged.

CONCLUSIONS

The effects of TRT on cardiovascular risk markers were ambiguous. We observed potentially harmful changes in cardiovascular risk parameters, markedly reduced subcutaneous fat and unchanged ectopic fat during TRT and a reduction in adiponectin levels. On the other hand, the decrease in leptin and leptin:adiponectin ratio assessments could reflect an amelioration of the cardiovascular risk profile linked to hyperleptinaemia in ageing men with T2D.

Reduction of calprotectin and phosphate during testosterone therapy in aging men: a randomized controlled trial

OBJECTIVES

To investigate the effect of testosterone treatment on biomarkers calprotectin, fibroblast growth factor 23 (FGF23), soluble Klotho, phosphate, calcium, parathyroid hormone, creatinine and estimated glomerular filtration rate.

DESIGN

Randomized, double-blinded, placebo-controlled study.

SETTING

Odense Androgen Study-the effect of Testim and training in hypogonadal men.

PARTICIPANTS

Men aged 60-78 years old with a low normal concentration of free of bioavailable testosterone <7.3 nmol/L and waist circumference >94 cm recruited from 2008 to 2009 (N = 48) by advertisement.

INTERVENTION

Participants were randomized to receive 5-10 g gel/50-100 mg testosterone (Testim^®, Ipsen, France) or 5-10 g gel/placebo.

RESULTS

The plasma levels of calprotectin and phosphate were significantly reduced in the group receiving testosterone therapy (gel) compared to the placebo group (p < 0.05). Testosterone treatment did not have any significant effect on plasma levels of FGF23 or soluble Klotho. The reduction in phosphate levels was inversely associated with bioavailable testosterone.

CONCLUSION

Compared to the placebo group, 6 months of testosterone therapy (gel) reduced calprotectin and phosphate levels suggesting decreased inflammation and decreased cardiovascular risk.

Brain-derived neurotrophic factor (BDNF) serum basal levels is not affected by power training in mobility-limited older adults - A randomized controlled trial

Brain-derived neurotrophic factor (BDNF) is a potential important factor involved in neuroplasticity, and may be a mediator for eliciting adaptations in neuromuscular function and physical function in older individuals following physical training. As power training taxes the neural system to a very high extent, it may be particularly effective in terms of eliciting increases in systemic BDNF levels. We examined the effects of 12weeks of power training on mature BDNF (mBDNF) and total BDNF (tBDNF) in mobility-limited older adults from the Healthy Ageing Network of Competence (HANC) study. We included 47 older men and women: n=22 in the training group (TG: progressive high intensity power training, 2 sessions per week; age 82.7±5.4years, 55% women) and n=25 in the control group (CG: no interventions; age 82.2±4.5years, 76% women). Following overnight fasting, basal serum levels of mBDNF and tBDNF were assessed (human ELISA kits) at baseline and post-intervention. At baseline, mBDNF and tBDNF levels were comparable in the two groups, TG and CG. Post-intervention, no significant within-group or between-group changes were observed in mBDNF or tBDNF. Moreover, when divided into responder tertiles based upon changes in mBDNF and tBDNF (i.e. decliners, maintainers, improvers), respectively, comparable findings were observed for TG and CG. Altogether, basal systemic levels of serum mBDNF and tBDNF are not affected in mobility-limited older adults following 12-weeks of power training, and do not appear to be a major mechanistic factor mediating neuroplasticity in mobility-limited older adults.

Self-Image and Risk of Suicide in Eating Disorders

Introduction

Suicide risk is increased in eating disorders (ED), and detection is key to prevention. Self-image as operationalized in the structural analysis of social behavior (SASB) model has been shown to be associated with symptoms, treatment dropout, and outcome. SASB is a circumplex organizing self-directed behaviors along affiliation (love vs. hate) and autonomy (set free vs. control) dimensions. In a recent study, SASB related to health care-detected suicide attempts in ED. Methodology in that study ensured high specificity but risked lower sensitivity in suicide variables, and with such a high-threat outcome, research is needed on additional variables related to risk.

Objectives and aims

We aimed to study associations between SASB self-image and clinician- and self-rated suicidality at presentation and predicted over 12 months in ED patients.

Methods

Adult patients (n = 551) from a Swedish clinical database included 19% anorexia, 32% bulimia, 7% binge ED, and 42% other ED. We ran separate regression models for these diagnostic groups using SASB questionnaire data, also controlling for general psychiatric and ED symptoms, and in longitudinal models including baseline of each outcome.

Results

SASB alone was associated with suicidality at presentation (9–67% variance explained) and predictively over 12 months (7–29%), and in the majority of models explained additional variance beyond baseline and clinical variables. Both affiliation and autonomy related to dependent variables in diagnosis-specific patterns.

Conclusions

The findings have implications for both theory and detection tools for suicide risk, as well as suggesting intervention targets to mitigate risk in treatment based on the well-validated SASB theory.

Disclosure of interest

The authors have not supplied their declaration of competing interest.