Traveling interface modulations and anisotropic front propagation in ammonia oxidation over Rh(110)

The bistable NH3 + O2 reaction over a Rh(110) surface was explored in the pressure range 10−6 -10−3 mbar and in the temperature range 300-900 K using photoemission electron microscopy and low energy electron microscopy as spatially resolving methods. We observed a history dependent anisotropy in front propagation, traveling interface modulations, transitions with secondary reaction fronts, and stationary island structures.Fil: Rafti, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentina. Leibniz-Universität Hannover; AlemaniaFil: Borkenhagen, Benjamin. Technische Universität Clausthal; AlemaniaFil: Lilenkamp, Gerhard. Technische Universität Clausthal; AlemaniaFil: Lovis, Florian. Leibniz-Universität Hannover; AlemaniaFil: Smolinsky, Tim. Leibniz-Universität Hannover; AlemaniaFil: Imbihl, Roland. Leibniz-Universität Hannover; Alemani

Cardioceptive accuracy is associated with arousal but not with valence and perceived exertion under physical load

Under resting conditions, cardioceptive accuracy-the acuity of the perception of heartbeats-is associated with the self-reported intensity of affective states but not with reported valence. Physical exertion elicits positive affect below the anaerobic threshold and negative affect above the threshold while arousal gradually increases. The current research aimed to study the associations between cardioceptive accuracy and characteristics of the affective response (arousal and valence) during physical activity. About 67 undergraduate students completed the Schandry task and rated their perceived exertion (Borg-scale) and affective experience (arousal and valence) under three physical loads (running on a treadmill below, around, and above the anaerobic threshold). Cardioceptive accuracy was associated with the arousal component of the affective states during physical activity but not with valence and perceived exertion

A systematic review of the effects of exercise interventions on body composition in HIV+ adults

Over the years, physical activity and exercise have been used to positively impact the health and quality of life of persons infected with HIV and, more recently, has been associated with a spectrum of body composition changes. The aim of this review was to examine the effects of various exercise interventions on body composition in HIV positive adults, using a search strategy of randomized, controlled trials (RCTs). A systematic review was performed by five independent reviewers using a predetermined protocol adapted from previous research for assessing the articles for inclusion, the extracted data, and methodological quality. Eight RCTs involving 430 (26% female) HIV positive adults performing exercise a minimum of thrice weekly for at least six weeks were finally selected: Four were progressive resistance training (PRT) studies, three were aerobic training (AT) studies, and one involved yoga. In the PRT studies, there were significant increases in three anthropometric measures, namely, body mass, sum of skinfolds and sum of limb girths. In the AT studies, significant decreases were found in seven anthropometric measures, namely, body mass index, waist-hip ratio, body mass, triceps skinfold, waist circumference and sum of skinfolds. With yoga, the changes were nonsignificant. Exercise contributes to improved body composition and, when applied safely, appears to be beneficial for adults living with HIV/AIDS. However, these findings should be interpreted cautiously due to the relatively few RCTs published to date. Future studies would benefit from increased attention to sample size, female participants, participant follow-up, complete statistical analysis and intention-to-treat analysis.Scopu

Fundamental investigations of thermal aging phenomena of model NOx storage systems

Investigations of the aging behavior induced by high temperatures coupled with oxidizing atmosphere of model NO x storage systems Ba/Al2O3 and Ba/CeO2 are reported in this paper. The samples were prepared, calcined and exposed to temperatures between 500 and 1000 °C in air for 12 h for thermal aging. Samples were characterized with XRD, HRSEM, DSC-TGA-MS and BET analyses. In XRD investigations of all model systems calcined at 500 °C for 2 h, the NO x storage component was present in form of BaCO3. The release of CO2 as a result of the decarbonization of the NO x storage component at increased temperatures was verified by thermogravimetric investigations. In the case of Ba/Al2O3, already during calcination a partial reaction of the NO x storage component with Al2O3 resulting in the formation of barium aluminate was observed. In the model system Ba/CeO2 the decomposition of the barium carbonate started above 780 °C and the formation of a barium cerium mixed oxide was observed. The presence of the barium containing NO x storage component has a strong influence on the specific surface area of the model NO x storage systems. The morphology and crystallite size of CeO2 modified with the barium containing NO x storage component exhibited distinct changes compared to the unmodified oxide. The NO x storage efficiency determined by model gas tests of freshly prepared and engine aged model NO x storage catalysts correlates well with the above described observations