Time-dependent postural control adaptations following a neuromuscular warm-up in female handball players:A randomized controlled trial

Background: Female handball athletes are at a particular risk of sustaining lower extremity injuries. The study examines time-dependent adaptations of static and dynamic balance as potential injury risk factors to a specific warm-up program focusing on neuromuscular control. Methods: Fourty one (24.0 +/- 5.9 years) female handball athletes were randomized to an intervention or control group. The intervention group implemented a 15-min specific neuromuscular warm-up program, three times per week for eleven weeks, whereas the control group continued with their regular warm-up. Balance was assessed at five time points. Measures included the star excursion balance test (SEBT), and center of pressure (COP) sway velocity during single-leg standing. Results: No baseline differences existed between groups in demographic data. Adherence to neuromuscular warm-up was 88.7 %. Mean COP sway velocity decreased significantly over time in the intervention group (-14.4 %; p <.001), but not in the control group (-6.2 %; p = 0.056). However, these effects did not differ significantly between groups (p = .098). Mean changes over time in the SEBT score were significantly greater (p = .014) in the intervention group (+5.48) compared to the control group (+3.45). Paired t-tests revealed that the first significant balance improvements were observed after 6 weeks of training. Conclusions: A neuromuscular warm-up positively influences balance variables associated with an increased risk of lower extremity injuries in female handball athletes. The course of adaptations suggests that a training volume of 15 min, three times weekly over at least six weeks produces measurable changes

Triplet correlations in two-dimensional colloidal model liquids

Three-body distribution functions in classical fluids have been theoretically investigated many times, but have never been measured directly. We present experimental three-point correlation functions that are computed from particle configurations measured by means of video-microscopy in two types of quasi-two-dimensional colloidal model fluids: a system of charged colloidal particles and a system of paramagnetic colloids. In the first system the particles interact via a Yukawa potential, in the second via a potential $\Gamma/r^{3}$. We find for both systems very similar results: on increasing the coupling between the particles one observes the gradual formation of a crystal-like local order due to triplet correlations, even though the system is still deep inside the fluid phase. These are mainly packing effects as is evident from the close resemblance between the results for the two systems having completely different pair-interaction potentials.Comment: many pages, 8 figures, contribution to the special issue in J.Phys. Cond. Mat. of the CECAM meeting in LYON ''Many-body....'

The GTPase ARFRP1 controls the lipidation of chylomicrons in the Golgi of the intestinal epithelium

The uptake and processing of dietary lipids by the small intestine is a multistep process that involves several steps including vesicular and protein transport. The GTPase ADP-ribosylation factor-related protein 1 (ARFRP1) controls the ARF-like 1 (ARL1)-mediated Golgi recruitment of GRIP domain proteins which in turn bind several Rab-GTPases. Here, we describe the essential role of ARFRP1 and its interaction with Rab2 in the assembly and lipidation of chylomicrons in the intestinal epithelium. Mice lacking Arfrp1 specifically in the intestine (Arfrp1vil−/−) exhibit an early post-natal growth retardation with reduced plasma triacylglycerol and free fatty acid concentrations. Arfrp1vil−/− enterocytes as well as Arfrp1 mRNA depleted Caco-2 cells absorbed fatty acids normally but secreted chylomicrons with a markedly reduced triacylglycerol content. In addition, the release of apolipoprotein A-I (ApoA-I) was dramatically decreased, and ApoA-I accumulated in the Arfrp1vil−/− epithelium, where it predominantly co-localized with Rab2. The release of chylomicrons from Caco-2 was markedly reduced after the suppression of Rab2, ARL1 and Golgin-245. Thus, the GTPase ARFRP1 and its downstream proteins are required for the lipidation of chylo­microns and the assembly of ApoA-I to these particles in the Golgi of intestinal epithelial cells

Airborne observations of peroxy radicals during the EMeRGe campaign in Europe

In this study, airborne measurements of the sum of hydroperoxyl (HO$_2$) and organic peroxy (RO$_2$) radicals that react with nitrogen monoxide (NO) to produce nitrogen dioxide (NO$_2$), coupled with actinometry and other key trace gases measurements, have been used to test the current understanding of the fast photochemistry in the outflow of major population centres. The measurements were made during the airborne campaign of the EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) project in Europe on board the High Altitude and Long Range Research Aircraft (HALO). The measurements of RO$^∗_2$ on HALO were made using the in situ instrument Peroxy Radical Chemical Enhancement and Absorption Spectrometer (PeRCEAS). RO$^∗_2$ is to a good approximation the sum of peroxy radicals reacting with NO to produce NO$_2$. RO$^∗_2$ mixing ratios up to 120 pptv were observed in air masses of different origins and composition under different local actinometric conditions during seven HALO research flights in July 2017 over Europe. Radical production rates were estimated using knowledge of the photolysis frequencies and the RO$^∗_2$ precursor concentrations measured on board, as well as the relevant rate coefficients. Generally, high RO$^∗_2$ concentrations were measured in air masses with high production rates. In the air masses investigated, RO$^∗_2$ is primarily produced by the reaction of O$^1$D with water vapour and the photolysis of nitrous acid (HONO) and of the oxygenated volatile organic compounds (OVOCs, e.g. formaldehyde (HCHO) and glyoxal (CHOCHO)). Due to their short lifetime in most environments, the RO$^∗_2$ concentrations are expected to be in a photostationary steady state (PSS), i.e. a balance between production and loss rates is assumed. The RO$^∗_2$ production and loss rates and the suitability of PSS assumptions to estimate the RO$^∗_2$ mixing ratios and variability during the airborne observations are discussed. The PSS assumption for RO$^∗_2$ is considered robust enough to calculate RO$^∗_2$ mixing ratios for most conditions encountered in the air masses measured. The similarities and discrepancies between measured and PSS calculated RO$^∗_2$ mixing ratios are discussed. The dominant terminating processes for RO$^∗_2$ in the pollution plumes measured up to 2000 m are the formation of nitrous acid, nitric acid, and organic nitrates. Above2000 m, HO$_2$–HO$_2$ and HO$_2$–RO$_2$ reactions dominate the RO$^∗_2$ removal. RO$^∗_2$ calculations by the PSS analytical expression inside the pollution plumes probed often underestimated the measurements. The underestimation is attributed to the limitations of the PSS equation used for the analysis. In particular, this expression does not account for the yields of RO$^∗_2$ from the oxidation and photolysis of volatile organic compounds, VOCs, and OVOCs other than those measured during the EMeRGe research flights in Europe. In air masses with NO mixing ratios ≤ 50 pptv and low VOC/NO ratios, the RO$^∗_2$ measured is overestimated by the analytical expression. This may be caused by the formation of H$_2$O and O$_2$ from OH and HO$_2$, being about 4 times faster than the rate of the OH oxidation reaction of the dominant OVOCs considered

Experience of gratitude, awe and beauty in life among patients with multiple sclerosis and psychiatric disorders

Background: Feelings of gratitude and awe facilitate perceptions and cognitions that go beyond the focus of illness and include positive aspects of one's personal and interpersonal reality, even in the face of disease. We intended to measure feelings of gratitude, awe, and experiences of beauty in life among patients with multiple sclerosis and psychiatric disorders, particularly with respect to their engagement in specific spiritual/religious practices and their life satisfaction. Methods: We conducted a cross-sectional survey with standardized questionnaires to measure engagement in various spiritual practices (SpREUK-P) and their relation to experiences of Gratitude, Awe and Beauty in Life and life satisfaction (BMLSS-10). In total, 461 individuals (41 +/- 13 years; 68% women) with multiple sclerosis (46%) and depressive (22%) or other psychiatric disorders (32%) participated. Results: Among participants, 23% never, 43% rarely, 24% often, and 10% frequently experienced Gratitude. In contrast, 41% never, 37% rarely, 17% often, and 6% frequently experienced Awe. Beauty in Life was never experienced by 8% of the sample, and 28% rarely, 46% often, and 18% frequently experienced it. Gratitude (F=9.2; p=.003) and Beauty in Life (F=6.0; p=.015) were experienced significantly more often by women than men. However, the experience of Awe did not differ between women and men (F=2.2; n.s.). In contrast to our hypothesis, Gratitude/Awe cannot explain any relevant variance in patients' life satisfaction (R-2=.04). Regression analyses (R-2=.42) revealed that Gratitude/Awe can be predicted best by a person's engagement in religious practices, followed by other forms of spiritual practices and life satisfaction. Female gender was a weak predictor and underlying disease showed no effect. Conclusions: Gratitude/Awe could be regarded as a life orientation towards noticing and appreciating the positive in life - despite the symptoms of disease. Positive spirituality/religiosity seems to be a source of gratitude and appreciation in life, whereas patients with neither spiritual nor religious sentiments (R-S-) seem to have a lower awareness for these feelings

The evolution of crystalline ordering for ligand-ornamented zinc oxide nanoparticles

Recent total scattering experiments have opened up the possibility to study nanoparticle formation in situ and to observe the structural transformation from precursor clusters to adult particles. Organic ligand molecules interact with precursors of metal oxide nanoparticles, yet their influence onto the evolution of crystallinity during particle formation has not been addressed in detail; nor have in situ total scattering experiments ventured into the field of low-concentration, room-temperature syntheses in organic solvents to date. In this report, we follow the crystallization of ZnO nanoparticles in ethanol in the presence of different organic ligands. Low coordinated zinc precursor clusters rapidly polymerize upon base addition to particles of ca. 1 nm in diameter. In situ SAXS experiments reveal that the overall particle size increases to 2 to 4 nm with advancing reaction time. Complementary in situ PDF experiments show smaller crystalline domain sizes, which are only one third to half as large as the particle diameter. The ZnO particles thus feature a crystalline core surrounded by a disordered shell. Both, the core and the shell diameter are influenced by the different surface-bound organic ligands, which prevent an immediate relaxation to fully crystalline particles. A slow crystallization takes place in solution. We assume a dynamic equilibrium of the ligand and solvent molecules at the particle surface, which enables gradual bond restructuring. With suitably adjusted synthesis conditions, in our case by a continuous base addition, we show how to bypass the disordered intermediates, allowing the spontaneous nucleation of fully crystalline nanoparticles

A Rigorous Geometric Derivation of the Chiral Anomaly in Curved Backgrounds

We discuss the chiral anomaly for a Weyl field in a curved background and show that a novel index theorem for the Lorentzian Dirac operator can be applied to describe the gravitational chiral anomaly. A formula for the total charge generated by the gravitational and gauge field background is derived directly in Lorentzian signature and in a mathematically rigorous manner. It contains a term identical to the integrand in the Atiyah–Singer index theorem and another term involving the η -invariant of the Cauchy hypersurfaces