2,943 research outputs found
Spina bifida-predisposing heterozygous mutations in Planar Cell Polarity genes and Zic2 reduce bone mass in young mice
Fractures are a common comorbidity in children with the neural tube defect (NTD) spina bifida. Mutations in the Wnt/planar cell polarity (PCP) pathway contribute to NTDs in humans and mice, but whether this pathway independently determines bone mass is poorly understood. Here, we first confirmed that core Wnt/PCP components are expressed in osteoblasts and osteoclasts in vitro. In vivo, we performed detailed µCT comparisons of bone structure in tibiae from young male mice heterozygous for NTD-associated mutations versus WT littermates. PCP signalling disruption caused by Vangl2 (Vangl2Lp/+) or Celsr1 (Celsr1Crsh/+) mutations significantly reduced trabecular bone mass and distal tibial cortical thickness. NTD-associated mutations in non-PCP transcription factors were also investigated. Pax3 mutation (Pax3Sp2H/+) had minimal effects on bone mass. Zic2 mutation (Zic2Ku/+) significantly altered the position of the tibia/fibula junction and diminished cortical bone in the proximal tibia. Beyond these genes, we bioinformatically documented the known extent of shared genetic networks between NTDs and bone properties. 46 genes involved in neural tube closure are annotated with bone-related ontologies. These findings document shared genetic networks between spina bifida risk and bone structure, including PCP components and Zic2. Genetic variants which predispose to spina bifida may therefore independently diminish bone mass
Intracellular interferons in fish : a unique means to combat viral infection
Peer reviewedPublisher PD
Flavor Physics in an SO(10) Grand Unified Model
In supersymmetric grand-unified models, the lepton mixing matrix can possibly
affect flavor-changing transitions in the quark sector. We present a detailed
analysis of a model proposed by Chang, Masiero and Murayama, in which the
near-maximal atmospheric neutrino mixing angle governs large new b -> s
transitions. Relating the supersymmetric low-energy parameters to seven new
parameters of this SO(10) GUT model, we perform a correlated study of several
flavor-changing neutral current (FCNC) processes. We find the current bound on
B(tau -> mu gamma) more constraining than B(B -> X_s gamma). The LEP limit on
the lightest Higgs boson mass implies an important lower bound on tan beta,
which in turn limits the size of the new FCNC transitions. Remarkably, the
combined analysis does not rule out large effects in B_s-B_s-bar mixing and we
can easily accomodate the large CP phase in the B_s-B_s-bar system which has
recently been inferred from a global analysis of CDF and DO data. The model
predicts a particle spectrum which is different from the popular Constrained
Minimal Supersymmetric Standard Model (CMSSM). B(tau -> mu gamma) enforces
heavy masses, typically above 1 TeV, for the sfermions of the degenerate first
two generations. However, the ratio of the third-generation and
first-generation sfermion masses is smaller than in the CMSSM and a (dominantly
right-handed) stop with mass below 500 GeV is possible.Comment: 44 pages, 5 figures. Footnote and references added, minor changes,
Fig. 2 corrected; journal versio
Lepton flavour violation in the MSSM
We derive new constraints on the quantities delta_{XY}^{ij}, X,Y=L,R, which
parametrise the flavour-off-diagonal terms of the charged slepton mass matrix
in the MSSM. Considering mass and anomalous magnetic moment of the electron we
obtain the bound |delta^{13}_{LL} delta^{13}_{RR}|<0.1 for tan beta=50, which
involves the poorly constrained element delta^{13}_{RR}. We improve the
predictions for the decays tau -> mu gamma, tau -> e gamma and mu -> e gamma by
including two-loop corrections which are enhanced if tan beta is large. The
finite renormalisation of the PMNS matrix from soft SUSY-breaking terms is
derived and applied to the charged-Higgs-lepton vertex. We find that the
experimental bound on BR(tau -> e gamma) severely limits the size of the MSSM
loop correction to the PMNS element U_{e3}, which is important for the proper
interpretation of a future U_{e3} measurement. Subsequently we confront our new
values for delta^{ij}_{LL} with a GUT analysis. Further, we include the effects
of dimension-5 Yukawa terms, which are needed to fix the Yukawa unification of
the first two generations. If universal supersymmetry breaking occurs above the
GUT scale, we find the flavour structure of the dimension-5 Yukawa couplings
tightly constrained by mu -> e gamma.Comment: 37 pages, 15 figures; typo in Equation (35) and (49) correcte
Effects of lowering body temperature via hyperhydration, with and without glycerol ingestion and practical precooling on cycling time trial performance in hot and humid conditions
Background: Hypohydration and hyperthermia are factors that may contribute to fatigue and impairment of endurance performance. The purpose of this study was to investigate the effectiveness of combining glycerol hyperhydration and an established precooling technique on cycling time trial performance in hot environmental conditions.Methods: Twelve well-trained male cyclists performed three 46.4-km laboratory-based cycling trials that included two climbs, under hot and humid environmental conditions (33.3 ± 1.1°C; 50 ± 6% r.h.). Subjects were required to hyperhydrate with 25 g.kg-1 body mass (BM) of a 4°C beverage containing 6% carbohydrate (CON) 2.5 h prior to the time trial. On two occasions, subjects were also exposed to an established precooling technique (PC) 60 min prior to the time trial, involving 14 g.kg-1 BM ice slurry ingestion and applied iced towels over 30 min. During one PC trial, 1.2 g.kg-1 BM glycerol was added to the hyperhydration beverage in a double-blind fashion (PC+G). Statistics used in this study involve the combination of traditional probability statistics and a magnitude-based inference approach.Results: Hyperhydration resulted in large reductions (-0.6 to -0.7°C) in rectal temperature. The addition of glycerol to this solution also lowered urine output (330 ml, 10%). Precooling induced further small (-0.3°C) to moderate (-0.4°C) reductions in rectal temperature with PC and PC+G treatments, respectively, when compared with CON (0.0°C, P\u3c0.05). Overall, PC+G failed to achieve a clear change in cycling performance over CON, but PC showed a possible 2% (30 s, P=0.02) improvement in performance time on climb 2 compared to CON. This improvement was attributed to subjects\u27 lower perception of effort reported over the first 10 km of the trial, despite no clear performance change during this time. No differences were detected in any other physiological measurements throughout the time trial.Conclusions: Despite increasing fluid intake and reducing core temperature, performance and thermoregulatory benefits of a hyperhydration strategy with and without the addition of glycerol, plus practical precooling, were not superior to hyperhydration alone. Further research is warranted to further refine preparation strategies for athletes competing in thermally stressful events to optimize health and maximize performance outcomes
Planck intermediate results. XLI. A map of lensing-induced B-modes
The secondary cosmic microwave background (CMB) -modes stem from the
post-decoupling distortion of the polarization -modes due to the
gravitational lensing effect of large-scale structures. These lensing-induced
-modes constitute both a valuable probe of the dark matter distribution and
an important contaminant for the extraction of the primary CMB -modes from
inflation. Planck provides accurate nearly all-sky measurements of both the
polarization -modes and the integrated mass distribution via the
reconstruction of the CMB lensing potential. By combining these two data
products, we have produced an all-sky template map of the lensing-induced
-modes using a real-space algorithm that minimizes the impact of sky masks.
The cross-correlation of this template with an observed (primordial and
secondary) -mode map can be used to measure the lensing -mode power
spectrum at multipoles up to . In particular, when cross-correlating with
the -mode contribution directly derived from the Planck polarization maps,
we obtain lensing-induced -mode power spectrum measurement at a significance
level of , which agrees with the theoretical expectation derived
from the Planck best-fit CDM model. This unique nearly all-sky
secondary -mode template, which includes the lensing-induced information
from intermediate to small () angular scales, is
delivered as part of the Planck 2015 public data release. It will be
particularly useful for experiments searching for primordial -modes, such as
BICEP2/Keck Array or LiteBIRD, since it will enable an estimate to be made of
the lensing-induced contribution to the measured total CMB -modes.Comment: 20 pages, 12 figures; Accepted for publication in A&A; The B-mode map
is part of the PR2-2015 Cosmology Products; available as Lensing Products in
the Planck Legacy Archive http://pla.esac.esa.int/pla/#cosmology; and
described in the 'Explanatory Supplement'
https://wiki.cosmos.esa.int/planckpla2015/index.php/Specially_processed_maps#2015_Lensing-induced_B-mode_ma
One Problem, Many Solutions: Simple Statistical Approaches Help Unravel the Complexity of the Immune System in an Ecological Context
The immune system is a complex collection of interrelated and overlapping solutions to the problem of disease. To deal with this complexity, researchers have devised multiple ways to measure immune function and to analyze the resulting data. In this way both organisms and researchers employ many tactics to solve a complex problem. One challenge facing ecological immunologists is the question of how these many dimensions of immune function can be synthesized to facilitate meaningful interpretations and conclusions. We tackle this challenge by employing and comparing several statistical methods, which we used to test assumptions about how multiple aspects of immune function are related at different organizational levels. We analyzed three distinct datasets that characterized 1) species, 2) subspecies, and 3) among- and within-individual level differences in the relationships among multiple immune indices. Specifically, we used common principal components analysis (CPCA) and two simpler approaches, pair-wise correlations and correlation circles. We also provide a simple example of how these techniques could be used to analyze data from multiple studies. Our findings lead to several general conclusions. First, relationships among indices of immune function may be consistent among some organizational groups (e.g. months over the annual cycle) but not others (e.g. species); therefore any assumption of consistency requires testing before further analyses. Second, simple statistical techniques used in conjunction with more complex multivariate methods give a clearer and more robust picture of immune function than using complex statistics alone. Moreover, these simpler approaches have potential for analyzing comparable data from multiple studies, especially as the field of ecological immunology moves towards greater methodological standardization
First Dating of a Recombination Event in Mammalian Tick-Borne Flaviviruses
The mammalian tick-borne flavivirus group (MTBFG) contains viruses associated with important human and animal diseases such as encephalitis and hemorrhagic fever. In contrast to mosquito-borne flaviviruses where recombination events are frequent, the evolutionary dynamic within the MTBFG was believed to be essentially clonal. This assumption was challenged with the recent report of several homologous recombinations within the Tick-borne encephalitis virus (TBEV). We performed a thorough analysis of publicly available genomes in this group and found no compelling evidence for the previously identified recombinations. However, our results show for the first time that demonstrable recombination (i.e., with large statistical support and strong phylogenetic evidences) has occurred in the MTBFG, more specifically within the Louping ill virus lineage. Putative parents, recombinant strains and breakpoints were further tested for statistical significance using phylogenetic methods. We investigated the time of divergence between the recombinant and parental strains in a Bayesian framework. The recombination was estimated to have occurred during a window of 282 to 76 years before the present. By unravelling the temporal setting of the event, we adduce hypotheses about the ecological conditions that could account for the observed recombination
Effects of postmortem calcium chloride injection on meat palatability traits of strip loin steaks from cattle supplemented with or without zilpaterol hydrochloride
An experiment was conducted to determine the effects of zilpaterol hydrochloride mM supplementation (ZH; 8.3 mg/kg on a DM basis for 20 d) and calcium chloride injection [CaCl2, 200 at 5% (wt/wt) at 72 h postmortem] on palatability traits of beef (Bos taurus) strip loin steaks. Select (USDA) strip loins were obtained from control (no ZH = 19) and ZH-supplemented carcasses (n = 20). Right and left sides were selected alternatively to serve as a control (no INJ) or CaCl2-injected (INJ) and stored at 4 degrees C Before injecting the subprimals (72 h postmortem), 2 steaks were cut for proximate, sarcomere length, and myofibrillar fragmentation index (MFI) analyses. At 7 d postmortem each strip loin was portioned into steaks, vacuum packaged, and aged for the appropriate period for Warner-Bratzler shear force (WBSF; 7, 14, 21, and 28 d postmortem), trained sensory analysis (14 and 21 d postmortem), purge loss (7 d), and MFI (3, 7, 14, 21, and 28 d postmortem). Results indicated steaks from both ZH supplementation and INJ had reduced WBSF values as days of postmortem aging increased. The WBSF values of ZH steaks were greater (P 0.05) due to ZH at 14, 21, or 28 d or due to INJ at any aging period. Trained panelists rated tenderness less in ZH steaks than steaks with no ZH at 14 d and 21 d. However, INJ improved (P < 0.05) the tenderness ratings and flavor intensity of the trained panelists, compared with their non-injected cohorts at 21 d. Zilpaterol hydrochloride supplementation reduced (P < 0.05) MFI values, but INJ resulted in greater (P < 0.05) MFI values compared with no INJ. Subprimals from ZH and INJ showed greater purge loss (P < 0.05). Although no interactions were found with ZH and CaCl2, injecting USDA Select strip loins from ZH-fed cattle can help reduce the normal WBSF variation as it does in steaks from non-ZH-fed cattle.90103584359
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