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Doped carbon-based systems have been extensively studied over the past decade as active electrocatalysts for both the two-electron (2e-) and four-electron (4e-) oxygen reduction reactions (ORRs). However, the mechanisms for ORR are generally poorly understood. Here, we report an extensive experimental and first-principles theoretical study of the ORR at nitrogen-doped reduced graphene oxide (NrGO). We synthesize three distinct NrGO catalysts and investigate their chemical and structural properties in detail via X-ray photoelectron spectroscopy, infrared and Raman spectroscopies, high-resolution transmission electron microscopy, and thin-film electrical conductivity. ORR experiments include the pH dependences of 2e- versus 4e- ORR selectivity, ORR onset potentials, Tafel slopes, and H/D kinetic isotope effects. These experiments show very different ORR behavior for the three catalysts, in terms of both selectivity and the underlying mechanism, which proceeds either via coupled proton-electron transfers (CPETs) or non-CPETs. Reasonable structural models developed from density functional theory rationalize this behavior. The key determinant between CPET vs non-CPET mechanisms is the electron density at the Fermi level under operating ORR conditions. Regardless of the reaction mechanism or electrolyte pH, however, we identify the ORR active sites as sp2 carbons that are located next to oxide regions. This assignment highlights the importance of oxygen functional groups, while details of (modest) N-doping may still affect the overall catalytic activity, and likely also the selectivity, by modifying the general chemical environment around the active site.

The aims of this study were to examine differences in self-schemas between persons living with HIV/AIDS with and without depressive symptoms, and the degree to which these self-schemas predict depressive symptoms in this population. Self-schemas are beliefs about oneself and include self-esteem, HIV symptom management self-efficacy, and self-compassion. Becks cognitive theory of depression guided the analysis of data from a sample of 1766 PLHIV from the USA and Puerto Rico. Sixty-five percent of the sample reported depressive symptoms. These symptoms were significantly (p ≤ 0.05), negatively correlated with age (r = -0.154), education (r = -0.106), work status (r = -0.132), income adequacy (r = -0.204, self-esteem (r = -0.617), HIV symptom self-efficacy (r = - 0.408), and self-kindness (r = - 0.284); they were significantly, positively correlated with gender (female/transgender) (r = 0.061), white or Hispanic race/ethnicity (r = 0.047) and self-judgment (r = 0.600). Fifty-one percent of the variance (F = 177.530 (df = 1524); p < 0.001) in depressive symptoms was predicted by the combination of age, education, work status, income adequacy, self-esteem, HIV symptom self-efficacy, and self-judgment. The strongest predictor of depressive symptoms was self-judgment. Results lend support to Becks theory that those with negative self-schemas are more vulnerable to depression and suggest that clinicians should evaluate PLHIV for negative self-schemas. Tailored interventions for the treatment of depressive symptoms in PLHIV should be tested and future studies should evaluate whether alterations in negative self-schemas are the mechanism of action of these interventions and establish causality in the treatment of depressive symptoms in PLHIV.

AimThis study represents an initial effort at examining the association between the construct of self-compassion and human immunodeficiency virus (HIV)-related anxiety in a multinational population with HIV disease.BackgroundPrevious studies have found that self-compassion is a powerful predictor of mental health, demonstrating positive and consistent linkages with various measures of affect, psychopathology and well-being, including anxiety.MethodsCross-sectional data from a multinational study conducted by the members of the International Nursing Network for HIV Research (n = 1986) were used. The diverse sample included participants from Canada, China, Namibia, the United States of America and the territory of Puerto Rico. Study measures included the anxiety subscale of the Symptom Checklist-90 instrument, the Brief Version Self-Compassion Inventory and a single item on anxiety from the Revised Sign and Symptom Checklist.FindingsStudy findings show that anxiety was significantly and inversely related to self-compassion across participants in all countries. We examined gender differences in self-compassion and anxiety, controlling for country. Levels of anxiety remained significantly and inversely related to self-compassion for both males (P = 0.000) and females (P = 0.000). Levels of self-compassion and anxiety varied across countries.ConclusionsSelf-compassion is a robust construct with cross-cultural relevance. A culturally based brief treatment approach aimed at increasing self-compassion may lend itself to the development of a cost effective adjunct treatment in HIV disease, including the management of anxiety symptoms.

The purpose of this study was to investigate the effects of stressful life events (SLE) on medication adherence (3 days, 30 days) as mediated by sense of coherence (SOC), self-compassion (SCS), and engagement with the healthcare provider (eHCP) and whether this differed by international site. Data were obtained from a cross-sectional sample of 2082 HIV positive adults between September 2009 and January 2011 from sites in Canada, China, Namibia, Puerto Rico, Thailand, and US. Statistical tests to explore the effects of stressful life events on antiretroviral medication adherence included descriptive statistics, multivariate analysis of variance, analysis of variance with Bonferroni post-hoc analysis, and path analysis. An examination by international site of the relationships between SLE, SCS, SOC, and eHCP with adherence (3 days and 30 days) indicated these combined variables were related to adherence whether 3 days or 30 days to different degrees at the various sites. SLE, SCS, SOC, and eHCP were significant predictors of adherence past 3 days for the United States (p = < 0.001), Canada (p = 0.006), and Namibia (p = 0.019). The combined independent variables were significant predictors of adherence past 30 days only in the United States and Canada. Engagement with the provider was a significant correlate for antiretroviral adherence in most, but not all, of these countries. Thus, the importance of eHCP cannot be overstated. Nonetheless, our findings need to be accompanied by the caveat that research on variables of interest, while enriched by a sample obtained from international sites, may not have the same relationships in each country.