2,439 research outputs found
Role of ABCB1 C3435T variant in response to antiepileptic drugs in epilepsy: a review
Over-expression of P-glycoprotein (P-gp), the encoded product of the ATP-binding cassette (ABC), sub-family B, member 1 (ABCB1/MDR1) gene, plays an important role in mediating multidrug resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation may in part explain inter-individual differences in phenotype-genotype relationships in the pharmacological response of epilepsy patients to AEDs. The synonymous C3435T polymorphism is one of the most common allelic variants in the ABCB1/MDR1 gene, proposed in the causation of refractory epilepsy. Many studies have shown the relationship between C3435T polymorphism and refractoriness to AEDs in epilepsy. However, there is controversy between the findings of various studies, that is, whether ABCB1/MDR1 C3435T gene polymorphism is associated with response to AEDs in epilepsy patients. This review provides a background and discusses the results of investigations on possible confounding factors affecting the interpretation and implementation of association studies in this area
Spin texture and magnetoroton excitations at nu=1/3
Neutral spin texture (ST) excitations at nu=1/3 are directly observed for the first time by resonant inelastic light scattering. They are determined to involve two simultaneous spin flips. At low magnetic fields, the ST energy is below that of the magnetoroton minimum. With increasing in-plane magnetic field these mode energies cross at a critical ratio of the Zeeman and Coulomb energies of eta(c)=0.020 +/- 0.001. Surprisingly, the intensity of the ST mode grows with temperature in the range in which the magnetoroton modes collapse. The temperature dependence is interpreted in terms of a competition between coexisting phases supporting different excitations. We consider the role of the ST excitations in activated transport at nu=1/3
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Superconductivity. Quasiparticle mass enhancement approaching optimal doping in a high-T(c) superconductor.
In the quest for superconductors with higher transition temperatures (T(c)), one emerging motif is that electronic interactions favorable for superconductivity can be enhanced by fluctuations of a broken-symmetry phase. Recent experiments have suggested the existence of the requisite broken-symmetry phase in the high-T(c) cuprates, but the impact of such a phase on the ground-state electronic interactions has remained unclear. We used magnetic fields exceeding 90 tesla to access the underlying metallic state of the cuprate YBa2Cu3O(6+δ) over a wide range of doping, and observed magnetic quantum oscillations that reveal a strong enhancement of the quasiparticle effective mass toward optimal doping. This mass enhancement results from increasing electronic interactions approaching optimal doping, and suggests a quantum critical point at a hole doping of p(crit) ≈ 0.18.This work is supported by the US Department of Energy BES \Science at 100 T," the
National Science Foundation, the State of Florida, the Natural Science and Engineering
Research Council of Canada and the Canadian Institute for Advanced Research. S.E.S. ac-
knowledges support from the Royal Society and the European Research Council under the
European Union's Seventh Framework Programme (FP7/2007-2013) / ERC Grant Agree-
ment no. 337425.This is the accepted manuscript. The final version is available at http://www.sciencemag.org/content/348/6232/317.abstract?sid=a882093c-ded2-481c-b62b-2f79a56b5689
Fragile charge order in the nonsuperconducting ground state of the underdoped high-temperature superconductors.
The normal state in the hole underdoped copper oxide superconductors has proven to be a source of mystery for decades. The measurement of a small Fermi surface by quantum oscillations on suppression of superconductivity by high applied magnetic fields, together with complementary spectroscopic measurements in the hole underdoped copper oxide superconductors, point to a nodal electron pocket from charge order in YBa2Cu3(6+δ). Here, we report quantum oscillation measurements in the closely related stoichiometric material YBa2Cu4O8, which reveals similar Fermi surface properties to YBa2Cu3(6+δ), despite the nonobservation of charge order signatures in the same spectroscopic techniques, such as X-ray diffraction, that revealed signatures of charge order in YBa2Cu3(6+δ). Fermi surface reconstruction in YBa2Cu4O8 is suggested to occur from magnetic field enhancement of charge order that is rendered fragile in zero magnetic fields because of its potential unconventional nature and/or its occurrence as a subsidiary to more robust underlying electronic correlations.B.T., A.S, and S.E.S. acknowledge support from the
Royal Society, the Winton Programme for the Physics of
Sustainability, and the European Research Council under
the European Unions Seventh Framework Programme
(grant number FP/2007-2013)/ ERC Grant Agreement
number 337425. N.H., Z.Z., F.F.B., and B.J.R. acknowl-
edge support for high-magnetic-field experiments from
the US Department of Energy, Office of Science, BES-
MSE `Science of 100 Tesla' programme. G.G.L. acknowl-
edges support from EPSRC grant EP/K012894/1. Work
at NIU was supported by The Institute for Nanoscience,
Engineering, and Technology - InSET. A portion of this
work was performed at the National High Magnetic Field
Laboratory, which is supported by NSF co-operative
agreement number DMR-0654118, the state of Florida,
and the DOE. We are grateful for the experimental assis-
tance provided by National High Magnetic Field Labora-
tory personnel, including J. B. Betts, Y. Coulter, M. Gor-
don, C. H. Mielke, A. Parish, R. McDonald, D. Rickel,
and D. Roybal.This is the author accepted manuscript. The final version is available from the National Academy of Sciences via http://dx.doi.org/10.1073/pnas.150416411
Influence of curing on pore properties and strength of alkali activated mortars
The paper investigates the effect of wet/dry, wet and dry curing on the pore properties and strength of an alkali activated cementitious (AACM) mortar. The pore characteristics were determined from the cumulative and differential pore volume curves obtained by mercury intrusion porosimetry. AACM mortars possess a bimodal pore size distribution while the control PC mortar is unimodal. AACM mortars have a lower porosity, higher capillary pore volume, lower gel pore volume and lower critical and threshold pore diameters than the PC mortar which indicate greater durability potential of AACMs. Wet/dry curing is optimum for AACM mortars while wet curing is optimum for the PC mortar. Shrinkage and retarding admixtures improve the strength and pore structure of the AACMs
Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion
This is the author accepted manuscript. The final version is available from the American Physiological Society via the DOI in this recordWe tested the hypotheses that the parameters of the power-duration relationship, estimated as the end-test power (EP) and work done above EP (WEP) during a 3-min all out exercise test (3MT), would be reduced progressively following 40 min, 80 min and 2 h of heavy-intensity cycling, and that carbohydrate (CHO) ingestion would attenuate the reduction in EP and WEP. Sixteen participants completed a 3MT without prior exercise (control), immediately after 40 min, 80 min and 2-h of heavy-intensity exercise while consuming a placebo beverage, and also after 2-h of heavy-intensity exercise while consuming a CHO supplement (60 g/h CHO). There was no difference in EP measured without prior exercise (260 ± 37 W) compared to EP following 40 min (268 ± 39 W) or 80 min (260 ± 40 W) of heavy-intensity exercise; however, after 2-h, EP was 9% lower compared to control (236 ± 47 W; P<0.05). There was no difference in WEP measured without prior exercise (17.9 ± 3.3 kJ) compared to after 40 min of heavy-intensity exercise (16.1 ± 3.3 kJ), but WEP was lower (P<0.05) than control after 80 min (14.7 ± 2.9 kJ) and 2-h (13.8 ± 2.7 kJ). Compared to placebo, CHO ingestion negated the reduction of EP following 2-h of heavy-intensity exercise (254 ± 49 W) but had no effect on WEP (13.5 ± 3.4 kJ). These results reveal a different time course for the deterioration of EP and WEP during prolonged endurance exercise and indicate that EP is sensitive to CHO availability
A five-year retrospective review of snakebite patients admitted to a tertiary university hospital in Malaysia
BACKGROUND
Although the majority of the snakebite cases in Malaysia are due to non-venomous snakes, venomous bites cause significant morbidity and mortality if treatment measures, especially ant-venom therapy, are delayed.
METHODS
To determine the demographic characteristics, we conducted a retrospective study on all snakebite patients admitted to the Emergency Department of Hospital Universiti Sains Malaysia (HUSM) from January 2006 to December 2010.
RESULTS
In the majority of the 260 cases that we found (138 cases or 52.9%), the snake species was unidentified. The most common venomous snakebites among the identified species were caused by cobras (52 cases or 20%). Cobra bites are significantly more likely to result in severe envenomation compared to non-cobra bites. Post hoc analysis also showed that cobra bite patients are significantly less likely to have complete recovery than non-cobra bite patients (48 cases, 75.0% vs. 53 cases, 94.6%; p = 0.003) and more likely to result in local gangrene (11 cases, 17.2% vs. 3 cases, 5.4%; p = 0.044).
CONCLUSION
Cobra bites are significantly more likely to result in severe envenomation needing anti-venom administration and more likely to result in local gangrene, and the patients are significantly less likely to have complete recovery than those with non-cobra bites
Differential Expressed Genes Identified Between African American and European American Keloid Fibroblasts
Keloids are benign fibroproliferative tumors due to dysregulation of collagen remodeling and abnormal wound healing. Although worldwide, there is a higher incidence of keloid disease (KD) in skin of color, little is known about this predisposition. In this study, we used one tissue micro array slide comprised of six AA and 6 EA punch biopsies of primary untreated keloid tissue from the head and neck area was created, following the NanoString® DSP Technology Access Program protocol. The GeoMx Human Whole Transcriptome Atlas Assay was performed, using morphology marker FAP. Polygonal region of interests selection strategy for Fibroblast Activation Protein (FAP) positive cells was conducted. Univariate analysis was performed, using linear regression models to identify differentially expressed genes (DEG) at a false discovery rate (FDR) of 0.05. Ingenuity pathway analysis (IPA) software was used to determine DEG pathway enrichment. 1,450 DEG were identified (p-va
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