Biophysical studies of the membrane location of the voltage-gated sensors in the HsapBK and KvAP K+ channels

AbstractThe membrane location of two fragments in two different K+-channels, the KvAP (from Aeropyrum pernix) and the HsapBK (human) corresponding to the putative “paddle” domains, has been investigated by CD, fluorescence and NMR spectroscopy. Both domains interact with q=0.5 phospholipid bicelles, DHPC micelles and with POPC vesicles. CD spectra demonstrate that both peptides become largely helical in the presence of phospholipid bicelles. Fluorescence quenching studies using soluble acrylamide or lipid-attached doxyl-groups show that the arginine-rich domains are located within the bilayered region in phospholipid bicelles. Nuclear magnetic relaxation parameters, T1 and 13C–1H NOE, for DMPC in DMPC/DHPC bicelles and for DHPC in micelles showed that the lipid acyl chains in the bicelles become less flexible in the presence of either of the fragments. An even more pronounced effect is seen on the glycerol carbons. 2H NMR spectra of magnetically aligned bicelles showed that the peptide derived from KvAP had no or little effect on bilayer order, while the peptide derived from HsapBK had the effect of lowering the order of the bilayer. The present study demonstrates that the fragments derived from the full-length proteins interact with the bilayered interior of model membranes, and that they affect both the local mobility and lipid order of model membrane systems

Motor-enriched learning activities can improve mathematical performance in preadolescent children

Objective: An emerging field of research indicates that physical activity can benefit cognitive functions and academic achievements in children. However, less is known about how academic achievements can benefit from specific types of motor activities (e.g., fine and gross) integrated into learning activities. Thus, the aim of this study was to investigate whether fine or gross motor activity integrated into math lessons (i.e., motor-enrichment) could improve children's mathematical performance. Methods: A 6-week within school cluster-randomized intervention study investigated the effects of motor-enriched mathematical teaching in Danish preadolescent children (n = 165, age = 7.5 ± 0.02 years). Three groups were included: a control group (CON), which received non-motor enriched conventional mathematical teaching, a fine motor math group (FMM) and a gross motor math group (GMM), which received mathematical teaching enriched with fine and gross motor activity, respectively. The children were tested before (T0), immediately after (T1) and 8 weeks after the intervention (T2). A standardized mathematical test (50 tasks) was used to evaluate mathematical performance. Furthermore, it was investigated whether motor-enriched math was accompanied by different effects in low and normal math performers. Additionally, the study investigated the potential contribution of cognitive functions and motor skills on mathematical performance. Results: All groups improved their mathematical performance from T0 to T1. However, from T0 to T1, the improvement was significantly greater in GMM compared to FMM (1.87 ± 0.71 correct answers) (p = 0.02). At T2 no significant differences in mathematical performance were observed. A subgroup analysis revealed that normal math-performers benefitted from GMM compared to both CON 1.78 ± 0.73 correct answers (p = 0.04) and FMM 2.14 ± 0.72 correct answers (p = 0.008). These effects were not observed in low math-performers. The effects were partly accounted for by visuo-spatial short-term memory and gross motor skills. Conclusion: The study demonstrates that motor enriched learning activities can improve mathematical performance. In normal math performers GMM led to larger improvements than FMM and CON. This was not the case for the low math performers. Future studies should further elucidate the neurophysiological mechanisms underlying the observed behavioral effects

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Stig T. Rasmussen anmelder: Tusind og én Nat. Udg. af Ellen Wulff & Kim Witthoff. 2013John Lind anmelder: Den Ryssiske Lov 1649. Oversat og kommenteret af Rasmus Æreboe 1721. Udg. af Lars P. Poulsen-Hansen. 2013Jesper Jakobsen anmelder: Raymond Birn: Royal Censorship of Books in Eighteenth–Century France. 2012Robert Bohn: John T. Lauridsen (udg.): Werner Bests korrespondance med Auswärtiges Amt og andre tyske akter vedrørende besættelsen af Danmark 1942-1945. 201

Acute exercise and motor memory consolidation:The role of exercise timing

High intensity aerobic exercise amplifies offline gains in procedural memory acquired during motor practice. This effect seems to be evident when exercise is placed immediately after acquisition, during the first stages of memory consolidation, but the importance of temporal proximity of the exercise bout used to stimulate improvements in procedural memory is unknown. The effects of three different temporal placements of high intensity exercise were investigated following visuomotor skill acquisition on the retention of motor memory in 48 young (24.0 ± 2.5 yrs), healthy male subjects randomly assigned to one of four groups either performing a high intensity (90% Maximal Power Output) exercise bout at 20 min (EX90), 1 h (EX90+1), 2 h (EX90+2) after acquisition or rested (CON). Retention tests were performed at 1 d (R1) and 7 d (R7). At R1 changes in performance scores after acquisition were greater for EX90 than CON (p<0.001) and EX90+2 (p=0.001). At R7 changes in performance scores for EX90, EX90+1, and EX90+2 were higher than CON (p<0.001, p=0.008, and p=0.008, resp.). Changes for EX90 at R7 were greater than EX90+2 (p=0.049). Exercise-induced improvements in procedural memory diminish as the temporal proximity of exercise from acquisition is increased. Timing of exercise following motor practice is important for motor memory consolidation

A material degradation study of novel FeCrAl alloys, stainless steels and nickel base alloy in fluidized bed heat exchangers of a waste-fired CFB boiler

This study aimed to evaluate the material degradation resistance of two newly developed FeCrAl alloys exposed within the loop seal region of an 85 MWth waste-fired CFB boiler in Sweden. In addition to the FeCrAl alloys, two commercial austenitic stainless steel and one nickel base (Ni-base) alloy were also studied. The samples were exposed for 6 and 12 months by clamping half-moon rings onto tubes of the installed superheater bundle, achieving a material temperature of 500–520 \ub0C. The material degradation of the samples was assessed by evaluating material loss using an ultrasonic thickness gauge in combination with a scanning electron microscope (SEM). Microstructural analysis was carried out using SEM coupled with Energy-dispersive X-ray spectroscopy (EDX). Both FeCrAl alloys showed promising results achieving material losses in the same range as the investigated austenitic stainless steels and the Ni-base alloy. A thin inward-growing Cr/Al-rich and thick outward-growing Fe-rich oxide were present for the FeCrAl alloys, and an internal nitridation zone was formed in the material matrix close to the metal/oxide interphase. The material loss and extent of the corrosion attack for the austenitic stainless steels varied depending on the alloy composition. However, the corrosion attack remained similar, as all the austenitic steels suffered from internal and intergranular corrosion. For the Ni-base alloy, the attack was defined by an internal Cr-rich oxide formation with no intergranular corrosion. This study suggests that the novel FeCrAl alloys provide satisfying resistance towards corrosion and erosion of the fluidized bed heat exchangers in the loop seal region of a waste-fired boiler. In addition, the stainless steel SX and the Ni-base alloy Sanicro\uae 69 performed well. Furthermore, the results revealed that corrosion rather than erosion was the dominating degradation process of the investigated samples, as deposit formation was observed on most of the samples as well as corrosion product layers. Thus, the erosive aspect of the attack was expected to be minor

Associations between patients' risk attitude and their adherence to statin treatment - a population based questionnaire and register study

Background: Poor adherence to medical treatment may have considerable consequences for the patients’ health and for healthcare costs to society. The need to understand the determinants for poor adherence has motivated several studies on socio-demographics and comorbidity. Few studies focus on the association between risk attitude and adherence. The aim of the present study was to estimate associations between patients’ adherence to statin treatment and different dimensions of risk attitude, and to identify subgroups of patients with poor adherence. Methods: Population-based questionnaire and register-based study on a sample of 6393 persons of the general. Danish population aged 20–79. Data on risk attitude were based on 4 items uncovering health-related as well as financial dimensions of risk attitude. They were collected through a web-based questionnaire and combined with register data on redeemed statin prescriptions, sociodemographics and comorbidity. Adherence was estimated by proportion of days covered using a cut-off point at 80 %. Results: For the dimension of health-related risk attitude, “Preference for GP visit when having symptoms”, riskneutral and risk-seeking patients had poorer adherence than the risk-averse patients, OR 0.80 (95 %-CI 0.68–0.95)and OR 0.83 (95 %-CI 0.71–0.98), respectively. No significant association was found between adherence and financial risk attitude. Further, patients in the youngest age group and patients with no CVD were less adherent to statin treatment. Conclusion: We find some indication that risk attitude is associated with adherence to statin treatment, and that risk-neutral and risk-seeking patients may have poorer adherence than risk-averse patients. This is important for clinicians to consider when discussing optimal treatment decisions with their patients. The identified subgroups with the poorest adherence may deserve special attention from their GP regarding statin treatment