Electrochemical properties of micro-batteries with single NCM-111 secondary particles as cathode

Although lithium ion batteries (LIB) are already used in numerous applications, e.g. as power source in portable devices, the optimization of the battery performance, such as life-time, cyclability and energy density, is of large interest for using LIBs in e.g. electrical vehicles or temporary storage systems for renewable energy sources. Typically, the performance of the cathode active material is investigated using composite electrodes. Advanced composite electrodes consist of a complex architecture with comparably large secondary particles (10 µm - 30 µm) of the active material built up from nanometer sized primary particles. Furthermore, they also contain additives influencing the electrochemical properties of the composite electrode. To avoid such influences and to further optimize the performance of the cathode’s active material a detailed understanding of the impact of the cathode architecture on the ionic and electronic transport processes is necessary. Please click Additional Files below to see the full abstract

Self-perceived quality of life predicts mortality risk better than a multi-biomarker panel, but the combination of both does best

<p>Abstract</p> <p>Background</p> <p>Associations between measures of subjective health and mortality risk have previously been shown. We assessed the impact and comparative predictive performance of a multi-biomarker panel on this association.</p> <p>Methods</p> <p>Data from 4,261 individuals aged 20-79 years recruited for the population-based Study of Health in Pomerania was used. During an average 9.7 year follow-up, 456 deaths (10.7%) occurred. Subjective health was assessed by SF-12 derived physical (PCS-12) and mental component summaries (MCS-12), and a single-item self-rated health (SRH) question. We implemented Cox proportional-hazards regression models to investigate the association of subjective health with mortality and to assess the impact of a combination of 10 biomarkers on this association. Variable selection procedures were used to identify a parsimonious set of subjective health measures and biomarkers, whose predictive ability was compared using receiver operating characteristic (ROC) curves, C-statistics, and reclassification methods.</p> <p>Results</p> <p>In age- and gender-adjusted Cox models, poor SRH (hazard ratio (HR), 2.07; 95% CI, 1.34-3.20) and low PCS-12 scores (lowest vs. highest quartile: HR, 1.75; 95% CI, 1.31-2.33) were significantly associated with increased risk of all-cause mortality; an association independent of various covariates and biomarkers. Furthermore, selected subjective health measures yielded a significantly higher C-statistic (0.883) compared to the selected biomarker panel (0.872), whereas a combined assessment showed the highest C-statistic (0.887) with a highly significant integrated discrimination improvement of 1.5% (p < 0.01).</p> <p>Conclusion</p> <p>Adding biomarker information did not affect the association of subjective health measures with mortality, but significantly improved risk stratification. Thus, a combined assessment of self-reported subjective health and measured biomarkers may be useful to identify high-risk individuals for intensified monitoring.</p

Cohort study of trials submitted to ethics committee identified discrepant reporting of outcomes in publications

OBJECTIVES To identify factors associated with discrepant outcome reporting in randomized drug trials. STUDY DESIGN AND SETTING Cohort study of protocols submitted to a Swiss ethics committee 1988-1998: 227 protocols and amendments were compared with 333 matching articles published during 1990-2008. Discrepant reporting was defined as addition, omission, or reclassification of outcomes. RESULTS Overall, 870 of 2,966 unique outcomes were reported discrepantly (29.3%). Among protocol-defined primary outcomes, 6.9% were not reported (19 of 274), whereas 10.4% of reported outcomes (30 of 288) were not defined in the protocol. Corresponding percentages for secondary outcomes were 19.0% (284 of 1,495) and 14.1% (334 of 2,375). Discrepant reporting was more likely if P values were <0.05 compared with P ≥ 0.05 [adjusted odds ratio (aOR): 1.38; 95% confidence interval (CI): 1.07, 1.78], more likely for efficacy compared with harm outcomes (aOR: 2.99; 95% CI: 2.08, 4.30) and more likely for composite than for single outcomes (aOR: 1.48; 95% CI: 1.00, 2.20). Cardiology (aOR: 2.34; 95% CI: 1.44, 3.79) and infectious diseases (aOR: 1.77; 95% CI: 1.01, 3.13) had more discrepancies compared with all specialties combined. CONCLUSION Discrepant reporting was associated with statistical significance of results, type of outcome, and specialty area. Trial protocols should be made freely available, and the publications should describe and justify any changes made to protocol-defined outcomes

Tailoring the magnetoresistance of MnAs/GaAs:Mn granular hybrid nanostructures

The magnetoresistanceproperties of GaAs:Mn/MnAs granular hybrid structures consisting of ferromagnetic MnAs clusters within a paramagnetic GaAs:Mn host differ considerably from those of paramagnetic and ferromagnetic (Ga,Mn)As alloys. We analyze the magnetoresistance effects on the basis of a resistor network model. Typical experimental findings are reproduced and their dependence on cluster density and random spatial arrangement of the clusters are revealed. Controlled spatial positioning of the MnAs clusters within the GaAs:Mn host offers interesting opportunities for optimizing the magnetoresistanceproperties for applications and for overcoming problems of miniaturization arising from cluster statistics

Quantitative modeling of the annealing-induced changes of the magnetotransport in Ga1−xMnxAs alloys

We study the changes of magnetoresistance induced by controlled thermal annealing at temperatures ranging from 300 to 600 °C of a Ga0.98Mn0.02As alloy grown by low-temperature molecular beam epitaxy. We use a resistor-network model for describing the electrical transport as a function of temperature and external magnetic field. The model is founded on classical semiconductor band transport and neglects many-body interactions. The peculiarities of dilute magnetic semiconductors, in particular, the magnetic-field induced changes of the density of states and the potential fluctuations due to the giant Zeeman splitting in the paramagnetic phase as well as spontaneous magnetization effects in the ferromagnetic phase, are accounted for in a mean-field fashion. This empirical transport model based on reasonable assumptions and realistic material parameters yields a satisfactory quantitative description of the experimentally obtained temperature and magnetic-field dependence of the resistivity of the entire series of annealed Ga0.98Mn0.02As samples, which exhibit metallic, semiconducting, and almost insulating transport behavior with increasing annealing temperature. Our analysis provides further understanding of the annealing-induced changes of the transport properties in dilute magnetic III-Mn-V semiconductors

The wealth of nations and the dissemination of cardiovascular research

BACKGROUND: This study aimed at understanding whether investigators from less wealthy countries were at a disadvantage in disseminating their research, after accounting for potential differences in research quality and infrastructure. METHODS AND RESULTS: In this bibliometric analysis a representative random selection of 10% (n=1002 studies) of all abstracts submitted to the European Society of Cardiology (ESC) congress 2006 was followed for publication and citation from September 2006 to December 2011. The main variable of interest was the per-capita gross domestic product (GDP) of the country of the principal investigator. Using multivariable models that adjusted for socioeconomic indicators and previously identified markers of research quality, we examined the relationship between per-capita GDP and three study endpoints: Acceptance at the ESC congress, full-text publication, and number of two-year citations. Among 1002 abstracts from 63 countries, per-capita GDP was positively correlated with all three study endpoints. After adjusting for markers of research quality and infrastructure, per-capita GDP remained a strong predictor for acceptance at the ESC congress (adjusted OR for every 10,000 USD increase in per-capita GDP, 1.44; 95% CI, 1.15 to 1.80), full-text publication within 5years (adjusted OR, 1.49; 95% CI, 1.17 to 1.90), and high citation frequency (adjusted OR, 2.30; 95% CI, 1.31 to 4.04). These findings were largely consistent in a subgroup of abstracts of high-quality, prospective clinical trials. CONCLUSION: Investigators in less wealthy countries face challenges to disseminate their research, even after accounting for potential differences in the quality of their work and research infrastructure