324 research outputs found

    Improved spatial separation of neutral molecules

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    We have developed and experimentally demonstrated an improved electrostatic deflector for the spatial separation of molecules according to their dipole-moment-to-mass ratio. The device features a very open structure that allows for significantly stronger electric fields as well as for stronger deflection without molecules crashing into the device itself. We have demonstrated its performance using the prototypical OCS molecule and we discuss opportunities regarding improved quantum-state-selectivity for complex molecules and the deflection of unpolar molecules.Comment: 6 figure

    A 12-week lifestyle intervention: effects on fatigue, fear, and nutritional status in children with a Fontan circulation

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    IntroductionChildren and adolescents with a Fontan circulation are less physically active compared to healthy peers. In the current study, effects of a 12-week lifestyle intervention on fatigue, fears regarding exercise, caloric intake, rest energy expenditure (REE), and body composition were measured in children with a Fontan circulation.MethodsThis study was a semi-cross-over randomized controlled trial. The lifestyle intervention consisted of a 12-week high-weight resistance training (three supervised training sessions a week) supported by high-protein diet (>2 g/kg) and tailored recommended caloric intake. Fatigue (measured by the validated PedsQol Multidimensional Fatigue Scale), fears regarding exercise (measured on a fear thermometer), REE (measured using indirect calorimetry), caloric intake and body composition using air displacement plethysmography, and four-skinfold method were measured before and after the intervention and control period.ResultsTwenty-seven pediatric Fontan patients, median age 12.9 years (IQR: 10.5–16.2), of the included 28 patients successfully completed the program. Before training, both child- and parent-reported levels of fatigue were significantly worse on all domains (general, sleep/rest, and cognitive fatigue) compared to healthy peers. After training, parent-reported fatigue significantly improved on the general and cognitive fatigue domains [effect size +16 points (7–25), p < 0.001, and +10 points (2–17), p = 0.015, compared to the control period]. Before training, fear regarding exercise scored on the fear thermometer was low for both children and parents (median score 1 and 2, respectively, on a scale of 0–8). After training, child-reported fear decreased further compared to the control period [effect size −1.4 points (−2.3 to −0.6), p = 0.001]. At baseline, children had increased REE +12% compared to reference values, which did not change after exercise. Children ate an average of 637 calories below recommended intake based on REE, caloric deficit became smaller after the intervention, and protein intake increased compared to the control period [−388 calories (−674 to −102), p = 0.008, and +15 g (0.4–30), p = 0.044]. Body fat percentage did not change significantly.ConclusionA 12-week lifestyle intervention improved parent-reported fatigue symptoms in the children, further decreased child-reported fears, and increased caloric and protein intake

    Leg-focused high-weight resistance training improves ventricular stroke volume, exercise capacity and strength in young patients with a Fontan circulation

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    INTRODUCTION: Effective therapy to improve exercise capacity in Fontan patients is lacking. Leg-focused high-weight resistance training might augment the peripheral muscle pump and thereby improve exercise capacity.METHODS: This randomized semi-cross-over controlled trial investigated effects of a 12-week leg-focused high-weight resistance training plus high-protein diet, on (sub)maximal exercise capacity, cardiac function (assessed with cardiovascular magnetic resonance), muscle strength and quality of life in pediatric Fontan patients.RESULTS: Twenty-eight pediatric Fontan patients were included, 27 patients, (median age 12.9 [10.5-15.7]), successfully completed the program. Peak oxygen uptake (PeakVO2) at baseline was reduced (33.3 ml/kg/min [27.1-37.4],73% [62-79] of predicted). After training PeakVO2/kg and Peak workload improved significantly with +6.2 ml/kg/min [95%CI: 3.4-9.0](+18%) p&lt;0.001 and +22 Watts [95%CI: 12-32](+18%) p&lt;0.001 respectively, compared to the control period. Indexed single ventricle stroke volume increased significantly (43 ml/beat/m2 [40-49] versus 46 [41-53], p=0.014), as did inferior vena cava flow (21 ml/beat/m2 [18-24] versus 23 [20-28], p=0.015), while superior vena cava flow remained unchanged. Strength of all measured leg muscles increased significantly compared to the control period. Self-reported quality of life improved on the physical functioning and change in health domains of the child health questionnaire, parent-reported quality of life improved on the bodily pain, general health perception, and change in health domains compared to the control period.CONCLUSION:In a relatively large group of 27 older Fontan children, 12-weeks of leg-focused high-weight resistance training improved exercise capacity, stroke volume, (sub)maximal exercise capacity, muscle strength, and domains of quality of life.</p

    Characterization of ftsZ Mutations that Render Bacillus subtilis Resistant to MinC

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    Background: Cell division in Bacillus subtilis occurs precisely at midcell. Positional control of cell division is exerted by two mechanisms: nucleoid occlusion, through Noc, which prevents division through nucleoids, and the Min system, where the combined action of the MinC, D and J proteins prevents formation of the FtsZ ring at cell poles or recently completed division sites. Methodology/Principal Findings: We used a genetic screen to identify mutations in ftsZ that confer resistance to the lethal overexpression of the MinC/MinD division inhibitor. The FtsZ mutants were purified and found to polymerize to a similar or lesser extent as wild type FtsZ, and all mutants displayed reduced GTP hydrolysis activity indicative of a reduced polymerization turnover. We found that even though the mutations conferred in vivo resistance to MinC/D, the purified FtsZ mutants did not display strong resistance to MinC in vitro. Conclusions/Significance: Our results show that in B. subtilis, overproduction of MinC can be countered by mutations that alter FtsZ polymerization dynamics. Even though it would be very likely that the FtsZ mutants found depend on other Z-ring stabilizing proteins such as ZapA, FtsA or SepF, we found this not to be the case. This indicates that the cell division process in B. subtilis is extremely robust.

    The Role for HNF-1β-Targeted Collectrin in Maintenance of Primary Cilia and Cell Polarity in Collecting Duct Cells

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    Collectrin, a homologue of angiotensin converting enzyme 2 (ACE2), is a type I transmembrane protein, and we originally reported its localization to the cytoplasm and apical membrane of collecting duct cells. Recently, two independent studies of targeted disruption of collectrin in mice resulted in severe and general defects in renal amino acid uptake. Collectrin has been reported to be under the transcriptional regulation by HNF-1α, which is exclusively expressed in proximal tubules and localized at the luminal side of brush border membranes. The deficiency of collectrin was associated with reduction of multiple amino acid transporters on luminal membranes. In the current study, we describe that collectrin is a target of HNF-1β and heavily expressed in the primary cilium of renal collecting duct cells. Collectrin is also localized in the vesicles near the peri-basal body region and binds to γ-actin-myosin II-A, SNARE, and polycystin-2-polaris complexes, and all of these are involved in intracellular and ciliary movement of vesicles and membrane proteins. Treatment of mIMCD3 cells with collectrin siRNA resulted in defective cilium formation, increased cell proliferation and apoptosis, and disappearance of polycystin-2 in the primary cilium. Suppression of collectrin mRNA in metanephric culture resulted in the formation of multiple longitudinal cysts in ureteric bud branches. Taken together, the cystic change and formation of defective cilium with the interference in the collectrin functions would suggest that it is necessary for recycling of the primary cilia-specific membrane proteins, the maintenance of the primary cilia and cell polarity of collecting duct cells. The transcriptional hierarchy between HNF-1β and PKD (polycystic kidney disease) genes expressed in the primary cilia of collecting duct cells has been suggested, and collectrin is one of such HNF-1β regulated genes

    Performance breakdown effects dissociate from error detection effects in typing

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    Mistakes in skilled performance are often observed to be slower than correct actions. This error slowing has been associated with cognitive control processes involved in performance monitoring and error detection. A limited literature on skilled actions, however, suggests that preerror actions may also be slower than accurate actions. This contrasts with findings from unskilled, discrete trial tasks, where preerror performance is usually faster than accurate performance. We tested 3 predictions about error-related behavioural changes in continuous typing performance. We asked participants to type 100 sentences without visual feedback. We found that (a) performance before errors was no different in speed than that before correct key-presses, (b) error and posterror key-presses were slower than matched correct key-presses, and (c) errors were preceded by greater variability in speed than were matched correct key-presses. Our results suggest that errors are preceded by a behavioural signature, which may indicate breakdown of fluid cognition, and that the effects of error detection on performance (error and posterror slowing) can be dissociated from breakdown effects (preerror increase in variability). © 2013 © 2013 The Experimental Psychology Society
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