2,125 research outputs found

    Impaired pre-competition wellbeing measures can negatively impact running performance in developmental youth female soccer players

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    This study aimed to determine the association between pre-competition perceived player wellbeing measures and subsequent relative and peak running performance of developmental youth female soccer players (n = 15, age: 16 ± 1 years). Total distance (TD), high-speed (&gt; 3.5 m/s) (HSRD) and very high-speed (&gt; 5.3 m/s) running (VHSRD) were expressed using 1-, 2- and 5-minute epochs and relative (per minute) calculations. Fatigue, sleep quality, upper and lower-body muscle soreness, stress, and mood wellbeing measures were collected via a self-reported questionnaire (1-5 Likert scale). Menstrual cycle phase was collected via a calendar-based countback method. Results demonstrated that reductions in stress was associated with decreased relative and peak TD in all epochs ( p = 0.008-0.040), relative and peak HSRD ( p = 0.006-0.039) in 2- and 5-minute epochs as well as VHSRD in 2-minute epochs ( p = 0.026). For example, a one-point reduction of 'normal' to 'relaxed' is associated with a decrease of 7 m/min in peak TD for 1-minute epochs. One-point increase in fatigue (e.g., 'normal' to 'more tired than normal') displayed a decrease of 7 m/min peak TD for 2-minute ( p = 0.048) and 9 m/min for 5-minute ( p = 0.007) rolling epochs. Likewise, one-point increase in lower-body muscle-soreness (e.g., 'normal' to 'increase in soreness/tightness') was associated with a reduction of 6 m/min peak VHSRD for 1-minute epochs ( p = 0.034). Results suggest that perceived player wellbeing can influence running performance. However, the magnitude of the change in player wellbeing should be considered in a practical sense. </p

    Biochemical Systematics of Notothenioid Fishes from Antarctica

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    Genetic variation at 30 protein-coding loci was examined in seven forms of notothenioid fishes from Antarctica. Multilocus heterozygosity varied from 0.018 to 0.078 across taxa. An analysis of the allozyme data revealed the probable existence of an unrecognized cryptic species within Trematomu5 bemacchii. Pagothenia borchgrevinki is as closely related to some species of Trematomus as are some species of Trematomus to each other. Speciation among the species of Trematomus and Pagothenia appears to have taken place primarily after the separation of Antarctica from Australia

    Shadow of a Colossus: A z=2.45 Galaxy Protocluster Detected in 3D Ly-a Forest Tomographic Mapping of the COSMOS Field

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    Using moderate-resolution optical spectra from 58 background Lyman-break galaxies and quasars at z∌2.3−3z\sim 2.3-3 within a 11.5â€Č×13.5â€Č11.5'\times13.5' area of the COSMOS field (∌1200 deg2\sim 1200\,\mathrm{deg}^2 projected area density or ∌2.4 h−1 Mpc\sim 2.4\,h^{-1}\,\mathrm{Mpc} mean transverse separation), we reconstruct a 3D tomographic map of the foreground Lyα\alpha forest absorption at 2.2<z<2.52.2<z<2.5 with an effective smoothing scale of σ3d≈3.5 h−1 Mpc\sigma_{3d}\approx3.5\,h^{-1}\,\mathrm{Mpc} comoving. Comparing with 61 coeval galaxies with spectroscopic redshifts in the same volume, we find that the galaxy positions are clearly biased towards regions with enhanced IGM absorption in the tomographic map. We find an extended IGM overdensity with deep absorption troughs at z=2.45z=2.45 associated with a recently-discovered galaxy protocluster at the same redshift. Based on simulations matched to our data, we estimate the enclosed dark matter mass within this IGM overdensity to be Mdm(z=2.45)=(9±4)×1013 h−1 M⊙M_{\rm dm} (z=2.45) = (9\pm4)\times 10^{13}\,h^{-1}\,\mathrm{M_\odot}, and argue based on this mass and absorption strength that it will form at least one z∌0z\sim0 galaxy cluster with M(z=0)=(3±2)×1014 h−1M⊙M(z=0) = (3\pm 2) \times 10^{14}\,h^{-1}\mathrm{M_\odot}, although its elongated nature suggests that it will likely collapse into two separate clusters. We also point out a compact overdensity of six MOSDEF galaxies at z=2.30z=2.30 within a r∌1 h−1 Mpcr\sim 1\,h^{-1}\,\mathrm{Mpc} radius and Δz∌0.006\Delta z\sim 0.006, which does not appear to have a large associated IGM overdensity. These results demonstrate the potential of Lyα\alpha forest tomography on larger volumes to study galaxy properties as a function of environment, as well as revealing the large-scale IGM overdensities associated with protoclusters and other features of large-scale structure.Comment: To be submitted to ApJ. Figure 3 can be viewed on Youtube: https://youtu.be/KeW1UJOPMY

    Effect of d-cycloserine on fear extinction training in adults with social anxiety disorder

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    © 2019 Hofmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Preclinical and clinical data have shown that D-cycloserine (DCS), a partial agonist at the N-methyl-d-aspartate receptor complex, augments the retention of fear extinction in animals and the therapeutic learning from exposure therapy in humans. However, studies with nonclinical human samples in de novo fear conditioning paradigms have demonstrated minimal to no benefit of DCS. The aim of this study was to evaluate the effects of DCS on the retention of extinction learning following de novo fear conditioning in a clinical sample. Eighty-one patients with social anxiety disorder were recruited and underwent a previously validated de novo fear conditioning and extinction paradigm over the course of three days. Of those, only 43 (53%) provided analyzable data. During conditioning on Day 1, participants viewed images of differently colored lamps, two of which were followed by with electric shock (CS+) and a third which was not (CS-). On Day 2, participants were randomly assigned to receive either 50 mg DCS or placebo, administered in a double-blind manner 1 hour prior to extinction training with a single CS+ in a distinct context. Day 3 consisted of tests of extinction recall and renewal. The primary outcome was skin conductance response to conditioned stimuli, and shock expectancy ratings were examined as a secondary outcome. Results showed greater skin conductance and expectancy ratings in response to the CS+ compared to CS- at the end of conditioning. As expected, this difference was no longer present at the end of extinction training, but returned at early recall and renewal phases on Day 3, showing evidence of return of fear. In contrast to hypotheses, DCS had no moderating influence on skin conductance response or expectancy of shock during recall or renewal phases. We did not find evidence of an effect of DCS on the retention of extinction learning in humans in this fear conditioning and extinction paradigm

    Imaging ultrafast excited state pathways in transition metal complexes by X-ray transient absorption and scattering using X-ray free electron laser source

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    This report will describe our recent studies of transition metal complex structural dynamics on the fs and ps time scales using an X-ray free electron laser source, Linac Coherent Light Source (LCLS). Ultrafast XANES spectra at the Ni K-edge of nickel(II) tetramesitylporphyrin (NiTMP) were successfully measured for optically excited state at a timescale from 100 fs to 50 ps, providing insight into its sub-ps electronic and structural relaxation processes. Importantly, a transient reduced state Ni(I) (π, 3d(x2−y2)) electronic state is captured through the interpretation of a short-lived excited state absorption on the low-energy shoulder of the edge, which is aided by the computation of X-ray transitions for postulated excited electronic states. The observed and computed inner shell to valence orbital transition energies demonstrate and quantify the influence of electronic configuration on specific metal orbital energies. A strong influence of the valence orbital occupation on the inner shell orbital energies indicates that one should not use the transition energy from 1s to other orbitals to draw conclusions about the d-orbital energies. For photocatalysis, a transient electronic configuration could influence d-orbital energies up to a few eV and any attempt to steer the reaction pathway should account for this to ensure that external energies can be used optimally in driving desirable processes. NiTMP structural evolution and the influence of the porphyrin macrocycle conformation on relaxation kinetics can be likewise inferred from this study

    Metalloprotein entatic control of ligand-metal bonds quantified by ultrafast x-ray spectroscopy

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    The multifunctional protein cytochrome c (cyt c) plays key roles in electron transport and apoptosis, switching function by modulating bonding between a heme iron and the sulfur in a methionine residue. This Fe-S(Met) bond is too weak to persist in the absence of protein constraints. We ruptured the bond in ferrous cyt c using an optical laser pulse and monitored the bond reformation within the protein active site using ultrafast x-ray pulses from an x-ray free-electron laser, determining that the Fe-S(Met) bond enthalpy is ~4 kcal/mol stronger than in the absence of protein constraints. The 4 kcal/mol is comparable with calculations of stabilization effects in other systems, demonstrating how biological systems use an entatic state for modest yet accessible energetics to modulate chemical function

    Chemokine CCL9 Is Upregulated Early in Chronic Kidney Disease and Counteracts Kidney Inflammation and Fibrosis

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    Inflammation and fibrosis play an important pathophysiological role in chronic kidney disease (CKD), with pro-inflammatory mediators and leukocytes promoting organ damage with subsequent fibrosis. Since chemokines are the main regulators of leukocyte chemotaxis and tissue inflammation, we performed systemic chemokine profiling in early CKD in mice. This revealed (C-C motif) ligands 6 and 9 (CCL6 and CCL9) as the most upregulated chemokines, with significantly higher levels of both chemokines in blood (CCL6: 3–4 fold; CCL9: 3–5 fold) as well as kidney as confirmed by Enzyme-linked Immunosorbent Assay (ELISA) in two additional CKD models. Chemokine treatment in a mouse model of early adenine-induced CKD almost completely abolished the CKD-induced infiltration of macrophages and myeloid cells in the kidney without impact on circulating leukocyte numbers. The other way around, especially CCL9-blockade aggravated monocyte and macrophage accumulation in kidney during CKD development, without impact on the ratio of M1-to-M2 macrophages. In parallel, CCL9-blockade raised serum creatinine and urea levels as readouts of kidney dysfunction. It also exacerbated CKD-induced expression of collagen (3.2-fold) and the pro-inflammatory chemokines CCL2 (1.8-fold) and CCL3 (2.1-fold) in kidney. Altogether, this study reveals for the first time that chemokines CCL6 and CCL9 are upregulated early in experimental CKD, with CCL9-blockade during CKD initiation enhancing kidney inflammation and fibrosis

    STAT1 Pathway Mediates Amplification of Metastatic Potential and Resistance to Therapy

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    BACKGROUND: Traditionally IFN/STAT1 signaling is connected with an anti-viral response and pro-apoptotic tumor-suppressor functions. Emerging functions of a constitutively activated IFN/STAT1 pathway suggest an association with an aggressive tumor phenotype. We hypothesized that tumor clones that constitutively overexpress this pathway are preferentially selected by the host microenvironment due to a resistance to STAT1-dependent cytotoxicity and demonstrate increased metastatic ability combined with increased resistance to genotoxic stress. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that clones of B16F1 tumors grown in the lungs of syngeneic C57BL/6 mice demonstrate variable transcriptional levels of IFN/STAT1 pathway expression. Tumor cells that constitutively overexpress the IFN/STAT1 pathway (STAT1(H) genotype) are selected by the lung microenvironment. STAT1(H) tumor cells also demonstrate resistance to IFN-gamma (IFNgamma), ionizing radiation (IR), and doxorubicin relative to parental B16F1 and low expressors of the IFN/STAT1 pathway (STAT1(L) genotype). Stable knockdown of STAT1 reversed the aggressive phenotype and decreased both lung colonization and resistance to genotoxic stress. CONCLUSIONS: Our results identify a pathway activated by tumor-stromal interactions thereby selecting for pro-metastatic and therapy-resistant tumor clones. New therapies targeted against the IFN/STAT1 signaling pathway may provide an effective strategy to treat or sensitize aggressive tumor clones to conventional cancer therapies and potentially prevent distant organ colonization
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