Mesomorphic flexible chain polymers based on silicon

Poly(dialkylsiloxane)s and poly(dialkylsilane)s form a similar type of columnar mesophase. Although, the polysilanes are stiffer than polysiloxanes, both classes of polymers may be considered to be flexible due to the ability to form chain-folded crystals. Chain flexibility rather than the presence of chain stiffness determines whether the columnar mesophase is formed. A certain amphiphilic character does not appear to be required, as polysiloxanes with short side groups, e.g. polydiethylsiloxane display the same mesophase behaviour as polydialkylsilanes with long side chains and other nonpolar flexible chain molecules. The importance of the entropy gain upon conformational disordering is reflected in the increase in temperature stability with increasing alkyl side group length and the absence of mesophase behaviour in the case of the dimethyl substituted polymers

Mindfulness in informal caregivers of palliative patients.

OBJECTIVES: Mindfulness is a concept of growing impact on psychotherapy and has been shown to be effective for stress reduction and to improve psychological well-being. Existential Behavioural Therapy (EBT) was developed to support relatives of palliative care (PC) patients to cope with their situation during caregiving and bereavement. Mindfulness training was a core element of the intervention. We investigated the relationship between mindfulness, mental distress, and psychological well-being in informal caregivers, and evaluated if the effects of the intervention were mediated by mindfulness. METHODS: Relatives of PC inpatients took part in a randomized-controlled EBT trial and completed the Cognitive and Affective Mindfulness Scale-Revised, items from the Five Facets of Mindfulness as well as the Brief Symptom Inventory, the Satisfaction with Life Scale, the WHOQOL-BREF, a numerical rating scale on quality of life (range 0-10), and the Schedule for Meaning in Life Evaluation at pre- and post-intervention, and a 3- and 12-months follow-up. RESULTS: One-hundred-and-thirty carers were included, most of them (71.6%) recently being bereaved at the beginning of the intervention. High correlations between mindfulness and mental distress (r = -0.51, p < 0.001) as well as life satisfaction (r = 0.52, p < 0.001) were found. Mindfulness was a significant predictor of improvement in psychological distress, meaning in life and quality of life three months after the intervention. The EBT effects were partly mediated by mindfulness. SIGNIFICANCE OF RESULTS: Mindfulness seems to be a promising concept in supporting informal caregivers of PC patients. Further research is needed to identify the required format and intensity of mindfulness practice necessary for improvement

Late Quaternary sedimentation off the western Sahara

Late Quaternary sediments on the West African continental margin between 24°N and 15°N were studied with RV METEOR (1971) and VALDIVIA (1975). Cores on the shelf were taken with a 6-m-vibrocorer, in deeper water mainly with a 12 m Kastenlot corer. During Holocene, and up to the present time, more or less and climatic conditions north of the Senegal River area reduced terrigenous supply. Therefore, the biogenic-carbonate content exceeds about 50%. Wüstenquarz numbers (red + yellow quartz : white quartz x 100) are high (20 to mmore than 200), indicating eolian input. The Senegal River supplied fine grained, green colored, terrigenous material with some plant debris. During Würm, the Mediterranean climatic zone with winter rains was shifted more than 5° to the South and was reaching Banc d'Arguin (at about 20°N). Therefore, the terrigenous supply was increased in this northern part and consequently the carbonate content and the Wüstenquartz numbers dropped below 50% and 10, respectively. The arid zone was also shifted to the south; as a consequence, the Senegal River did not reach the sea, eolian supply diluted the biogenic carbonates, and increased Wüstenquartz numbers to more than 200. Eolian dunes covered parts of the shelf. Ratios of radiolarians/plankonic foraminifera and planktonic/benthonic organisms and sedimentation rates of organic carbon indicate stronger upwelling in the northern region. Turbidity currents were more frequent, eroding as much as a third of the material supplied ba pelagic sedimentation

BNP controls early load-dependent regulation of SERCA through calcineurin

Heart failure is characterised by reduced expression of sarcoplasmic reticulum calcium-ATPase (SERCA) and increased expression of B-type natriuretic peptide (BNP). The present study was performed to investigate causality of this inverse relationship under in vivo conditions in the transversal aortic constriction mouse model (TAC). Left ventricular SERCA-mRNA expression was significantly upregulated in TAC by 32% after 6 h, but not different from sham after 24 h. Serum proANP and BNP levels were increased in TAC after 24 h (BNP +274%, p < 0.01; proANP +60%, p < 0.05), but only proANP levels were increased after 6 h (+182%, p < 0.01). cGMP levels were only increased 24 h after TAC (+307%, p < 0.01), but not 6 h after TAC. BNP infusion inhibited the increase in SERCA expression 6 h after TAC. In BNP-receptor-knockout animals (GC-A), the expression of SERCA was still significantly increased 24 h after TAC at the mRNA level by 35% (p < 0.05), as well as at the protein level by 25% (p < 0.05). MCIP expression as an indicator of calcineurin activity was regulated in parallel to SERCA after 6 and 24 h. MCIP-mRNA was increased by 333% 6 h after TAC, but not significantly different from sham after 24 h. In the GC-A-KO mice, MCIP-mRNA was significantly increased in TAC compared to WT after 24 h. In mice with BNP infusion, MCIP was significantly lower 6 h after TAC compared to control animals. In conclusion, mechanical load leads to an upregulation of SERCA expression. This is followed by upregulation of natriuretic peptides with subsequent suppression of SERCA upregulation. Elevated natriuretic peptides may suppress SERCA expression by inhibition of calcineurin activity via activation of GC-A

Impaired Ca2+-handling in HIF-1α+/− mice as a consequence of pressure overload

The hypoxia-inducible factor (HIF)-1 is critically involved in the cellular adaptation to a decrease in oxygen availability. The influence of HIF-1α for the development of cardiac hypertrophy and cardiac function that occurs in response to sustained pressure overload has been mainly attributed to a challenged cardiac angiogenesis and cardiac hypertrophy up to now. Hif-1α+/+ and Hif-1α+/− mice were studied regarding left ventricular hypertrophy and cardiac function after being subjected to transverse aortic constriction (TAC). After TAC, both Hif-1α+/+ and Hif-1α+/− mice developed left ventricular hypertrophy with increased posterior wall thickness, septum thickness and increased left ventricular weight to a similar extent. No significant difference in cardiac vessel density was observed between Hif-1α+/+ and Hif-1α+/− mice. However, only the Hif-1α+/− mice developed severe heart failure as revealed by a significantly reduced fractional shortening mostly due to increased end-systolic left ventricular diameter. On the single cell level this correlated with reduced myocyte shortenings, decreased intracellular Ca2+-transients and SR-Ca2+ content in myocytes of Hif-1a+/− mice. Thus, HIF-1α can be critically involved in the preservation of cardiac function after chronic pressure overload without affecting cardiac hypertrophy. This effect is mediated via HIF-dependent modulation of cardiac calcium handling and contractility