14,887 research outputs found
Effect of abdominal binding on respiratory mechanics during exercise in athletes with cervical spinal cord injury
West CR, Goosey-Tolfrey VL, Campbell IG, Romer LM. Effect of
abdominal binding on respiratory mechanics during exercise in athletes
with cervical spinal cord injury. J Appl Physiol 117: 36–45, 2014. First
published May 22, 2014; doi:10.1152/japplphysiol.00218.2014.—We
asked whether elastic binding of the abdomen influences respiratory
mechanics during wheelchair propulsion in athletes with cervical
spinal cord injury (SCI). Eight Paralympic wheelchair rugby players
with motor-complete SCI (C5-C7) performed submaximal and maximal
incremental exercise tests on a treadmill, both with and without
abdominal binding. Measurements included pulmonary function,
pressure-derived indices of respiratory mechanics, operating lung
volumes, tidal flow-volume data, gas exchange, blood lactate, and
symptoms. Residual volume and functional residual capacity were
reduced with binding (77 18 and 81 11% of unbound, P 0.05),
vital capacity was increased (114 9%, P 0.05), whereas total lung
capacity was relatively well preserved (99 5%). During exercise,
binding introduced a passive increase in transdiaphragmatic pressure,
due primarily to an increase in gastric pressure. Active pressures
during inspiration were similar across conditions. A sudden, sustained
rise in operating lung volumes was evident in the unbound condition,
and these volumes were shifted downward with binding.
Expiratory flow limitation did not occur in any subject and there
was substantial reserve to increase flow and volume in both
conditions. V ˙ O2 was elevated with binding during the final stages
of exercise (8 –12%, P 0.05), whereas blood lactate concentration
was reduced (16 –19%, P 0.05). V ˙ O2/heart rate slopes were
less steep with binding (62 35 vs. 47 24 ml/beat, P 0.05).
Ventilation, symptoms, and work rates were similar across conditions.
The results suggest that abdominal binding shifts tidal
breathing to lower lung volumes without influencing flow limitation,
symptoms, or exercise tolerance. Changes in respiratory
mechanics with binding may benefit O2 transport capacity by an
improvement in central circulatory function.This article has been made available through the Brunel Open Access Publishing Fund
Light MSSM Higgs boson mass to three-loop accuracy
The light CP even Higgs boson mass, Mh, is calculated to three-loop accuracy
within the Minimal Supersymmetric Standard Model (MSSM). The result is
expressed in terms of DRbar parameters and implemented in the computer program
H3m. The calculation is based on the proper approximations and their
combination in various regions of the parameter space. The three-loop effects
to Mh are typically of the order of a few hundred MeV and opposite in sign to
the two-loop corrections. The remaining theory uncertainty due to higher order
perturbative corrections is estimated to be less than 1 GeV.Comment: 39 pages, 13 figures. v2: minor changes, typos fixe
Precipitation of PEG/Carboxyl-modified gold nanoparticles with magnesium pyrophosphate : a new platform for real-time monitoring of loop-mediated isothermal amplification
2016-2017 > Academic research: refereed > Publication in refereed journal201804_a bcmaVersion of RecordRGCOthersRGC: 501413Others: PGMS Project IDs: P0009500 and P0009150Publishe
Strained graphene structures: from valleytronics to pressure sensing
Due to its strong bonds graphene can stretch up to 25% of its original size
without breaking. Furthermore, mechanical deformations lead to the generation
of pseudo-magnetic fields (PMF) that can exceed 300 T. The generated PMF has
opposite direction for electrons originating from different valleys. We show
that valley-polarized currents can be generated by local straining of
multi-terminal graphene devices. The pseudo-magnetic field created by a
Gaussian-like deformation allows electrons from only one valley to transmit and
a current of electrons from a single valley is generated at the opposite side
of the locally strained region. Furthermore, applying a pressure difference
between the two sides of a graphene membrane causes it to bend/bulge resulting
in a resistance change. We find that the resistance changes linearly with
pressure for bubbles of small radius while the response becomes non-linear for
bubbles that stretch almost to the edges of the sample. This is explained as
due to the strong interference of propagating electronic modes inside the
bubble. Our calculations show that high gauge factors can be obtained in this
way which makes graphene a good candidate for pressure sensing.Comment: to appear in proceedings of the NATO Advanced Research Worksho
Large enhancement of the thermopower in NaCoO at high Na doping
Research on the oxide perovskites has uncovered electronic properties that
are strikingly enhanced compared with those in conventional metals. Examples
are the high critical temperatures of the cuprate superconductors and the
colossal magnetoresistance in the manganites. The conducting layered cobaltate
displays several interesting electronic phases as is varied
including water-induced superconductivity and an insulating state that is
destroyed by field. Initial measurements showed that, in the as-grown
composition, displays moderately large thermopower and
conductivity . However, the prospects for thermoelectric cooling
applications faded when the figure of merit was found to be small at this
composition (0.60.7). Here we report that, in the poorly-explored
high-doping region 0.75, undergoes an even steeper enhancement. At the
critical doping 0.85, (at 80 K) reaches values 40 times
larger than in the as-grown crystals. We discuss prospects for low-temperature
thermoelectric applications.Comment: 6 pages, 7 figure
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) suppresses spheroids attachment on endometrial epithelial cells through the down-regulation of the Wnt-signaling pathway
The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects embryo development, implantation and fertility in humans. The underlying molecular mechanism by which TCDD suppresses implantation remains largely unknown. We used the trophoblastic spheroids (embryo surrogate)-endometrial cells co-culture assay to study the attachment of trophoblastic spheroids (BeWo and Jeg-3) onto the endometrial epithelial (RL95-2 and Ishikawa) cells. TCDD dose-dependently induced cytochrome P450 1A1 (Cyp1A1) expression in trophoblastic and endometrial epithelial cells. Moreover, TCDD at 1 and 10. nM suppressed β-catenin (a Wnt-signaling molecule) and E-cadherin expression, as well as spheroids attachment onto endometrial cells. Interestingly, activation of the canonical Wnt-signaling pathway via Wnt3a or lithium chloride reverted the suppressive effect of TCDD on β-catenin and E-cadherin expressions in the BeWo and RL95-2 cells, and restored the spheroids attachment rate to be comparable to the untreated controls. Taken together, TCDD induces Cyp1A1 expression, modulates the Wnt-signaling pathway and suppresses spheroids attachment onto endometrial cells. © 2011 Elsevier Inc.postprin
Hormonal regulation of endometrial olfactomedin expression and its suppressive effect on spheroid attachment onto endometrial epithelial cells
Background Olfactomedin (Olfm) is a member of a diverse group of extracellular matrix proteins important for neuronal growth. Recent microarray studies identified Olfm as one of the down-regulated transcripts in receptive endometrium at the time of embryo attachment and implantation. However, the underlying molecular mechanisms that govern Olfm expression and its effect on embryo attachment and implantation remain unknown. Methods The expression of Olfm in the human endometrium was investigated by real-time PCR, western blotting and immunohistochemistry on human endometrial biopsies from natural and ovarian stimulated cycles. To investigate the function of Olfm in trophoblastendometrial cell attachment, an in vitro spheroid-endometrial cell co-culture study was performed. Results Human endometrial Olfactomedin-1 and -2(Olfm-1 and -2) transcripts decreased significantly from the proliferative to the secretory phases of the menstrual cycle. Olfm protein was strongly expressed in the luminal and glandular epithelium and moderately in the stromal cells of human endometria. Ovarian stimulation significantly decreased (P < 0.05) the expression of endometrial Olfm-1 and -2 transcripts in patients receiving IVF treatment when compared with those in the natural cycle. Importantly, recombinant Olfm-1 suppressed JAr spheroid attachment onto Ishikawa cells and this was not associated with changes of β-catenin and E-cadherin expression in trophoblast and endometrial cells. Conclusions Decreased expression of Olfm during the receptive phase of the endometrium may allow successful trophoblast attachment for implantation. © 2010 The Author.postprin
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Bridge-specific fragility analysis: when is it really necessary?
In seismic assessment of bridges the research focus has recently shifted on the derivation of bridge-specific fragility curves that account for the effect of different geometry, structural system, component and soil properties, on the seismic behaviour. In this context, a new, component-based methodology for the derivation of bridge-specific fragility curves has been recently proposed by the authors, with a view to overcoming the inherent difficulties in assessing all bridges of a road network and the drawbacks of existing methodologies, which use the same group of fragility curves for bridges within the same typological class. The main objective of this paper is to critically assess the necessity of bridge-specific fragility analysis, starting from the effect of structure-specific parameters on component capacity (limit state thresholds), seismic demand, and fragility curves. The aforementioned methodology is used to derive fragility curves for all bridges within an actual road network, with a view to investigating the consistency of adopting generic fragility curves for bridges that fall within the same class and quantifying the degree of over- or under-estimation of the probability of damage when generic bridge classes are considered. Moreover, fragility curves for all representative bridges of the analysed concrete bridge classes are presented to illustrate the differentiation in bridge fragility for varying structural systems, bridge geometry, total bridge length and maximum pier height. Based on the above, the relevance of bridge-specific fragility analysis is assessed, and pertinent conclusions are drawn
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