2,180 research outputs found
Reducing the Tension Between the BICEP2 and the Planck Measurements: A Complete Exploration of the Parameter Space
A large inflationary tensor-to-scalar ratio is reported by the BICEP2 team based on their B-mode
polarization detection, which is outside of the confidence level of the
Planck best fit model. We explore several possible ways to reduce the tension
between the two by considering a model in which ,
, and the neutrino parameters and
are set as free parameters. Using the Markov Chain
Monte Carlo (MCMC) technique to survey the complete parameter space with and
without the BICEP2 data, we find that the resulting constraints on
are consistent with each other and the apparent tension
seems to be relaxed. Further detailed investigations on those fittings suggest
that probably plays the most important role in reducing the
tension. We also find that the results obtained from fitting without adopting
the consistency relation do not deviate much from the consistency relation.
With available Planck, WMAP, BICEP2 and BAO datasets all together, we obtain
, ,
, and
; if the consistency relation is
adopted, we get .Comment: 8 pages, 4 figures, submitted to PL
Antisense-induced suppression of taxoid 14β-hydroxylase gene expression in transgenic Taxus × media cells
The enzyme taxoid 14β-hydroxylase (14OH) directs a side-route of taxol pathway to 14β-hydroxy taxoids. Suppression of this side-route could increase the production of taxol. To suppress taxoid 14β- hydroxylase gene (14OH) expression in theTaxus × media TM3 cell line, antisense RNA inhibition approach was used in this study. Following the construction of an antisense RNA expression vector of 14OH from Taxus chinensis, the antisense 14OH cDNA (as14OH) was introduced into TM3 cells by Agrobacterium tumefaciens-mediated transformation. Southern blot analysis of hygromycin phosphotransferase gene (HYG) revealed that this selection gene was integrated successfully into the genome of Taxus × media cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the 14OH mRNA level in transgenic cells dropped dramatically, suggesting that the expression of endogenous14OH gene was significantly suppressed by the exogenous as14OH gene. Correspondingly, the total yield of three major C-14 oxygenated taxoids (yunnanxane, taxuyunnanine C, sinenxan C) was markedly reduced in the silenced cell lines when compared with those of the nontransgenic controls. These results indicated that the antisense RNA strategy is a useful tool in suppressing the expression of genes in Taxus and this method could be used to silence other important genes that divert Taxol pathway to side-route metabolites
Uniaxial dynamical decoupling for an open quantum system
Dynamical decoupling (DD) is an active and effective method for suppressing
decoherence of a quantum system from its environment. In contrast to the
nominal biaxial DD,this work presents a uniaxial decoupling protocol that
requires a significantly reduced number of pulses and a much lower bias field
satisfying the "magic" condition.We show this uniaxial DD protocol works
effectively in a number of model systems of practical interests, e.g., a spinor
atomic Bose-Einstein condensate in stray magnetic fields (classical noise), or
an electron spin coupled to nuclear spins (quantum noise) in a semiconductor
quantum dot. It requires only half the number of control pulses and a 10-100
times lower bias field for decoupling as normally employed in the above
mentioned illustrative examples,and the overall efficacy is robust against
rotation errors of the control pulses. The uniaxial DD protocol we propose
shines new light on coherent controls in quantum computing and quantum
information processing, quantum metrology, and low field nuclear magnetic
resonance.Comment: 10 pages, 8 figure
The radiosensitization effects of Endostar on human lung squamous cancer cells H-520
<p>Abstract</p> <p>Background</p> <p>The present study mainly aimed to investigate the direct effects of Endostar (ES) on the proliferation and radiosensitivity of human lung squamous cancer cell line H-520.</p> <p>Results</p> <p>ES significantly inhibited H-520 cell proliferation in a time- and dose-dependent manner. According to the colony-forming assays, ES could increase the H-520 cell radiosensitivity. ES induced cell apoptosis, the apoptosis rate increased with the raise of ES concentration. Irradiation induced significantly higher apoptosis rate in ES-treated H-520 cells than non-treated H-520 cells. ES induced cell cycle distribution and G<sub>0</sub>/G<sub>1 </sub>arrest in H-520 cells, whereas irradiation induced G<sub>2</sub>/M arrest. The phospho-p38-MAPK and p-Akt protein levels were decreased in H-520 cells after ES treatment. Furthermore, activated caspase protein level increased and Bcl-2 protein levels decreased after treatment with ES and irradiation.</p> <p>Conclusion</p> <p>ES significantly enhanced the sensitivity of H-520 cells to irradiation by inhibition of cellular proliferation, promotion of cell apoptosis and redistribution of cell cycle, possibly via deactivation of Akt pathway. The present study supports the possibility to use the combination of ES and ionizing irradiation to treat patients with lung squamous cell cancer in clinics.</p
The universal "heartbeat" oscillations in black hole systems accross the mass-scale
The hyperluminous X-ray source (HLX-1, the peak X-ray luminosity ) near the spiral galaxy ESO 243-49 is possibly the best
candidate for intermediate mass black hole (IMBH), which underwent recurrent
outbursts with a period of days. The physical reason for this
quasi-periodic variability is still unclear. We explore the possibility of
radiation-pressure instability in accretion disk by modeling the light curve of
HLX-1, and find that it can roughly reproduce the duration, period and
amplitude of the recurrent outbursts HLX-1 with an IMBH of ~10^5Msun. Our
result provides a possible mechanism to explain the recurrent outbursts in
HLX-1. We further find a universal correlation between the outburst duration
and the bolometric luminosity for the BH sources with a very broad mass range
(e.g., X-ray binaries, XRBs, HLX-1 and active galactic nuclei, AGNs), which is
roughly consistent with the prediction of radiation-pressure instability of the
accretion disk. These results imply that "heartbeat" oscillations triggered by
radiation-pressure instability may appears in different-scale BH systems.Comment: ApJ in press; 15 pages, 5 Figure
Effect of polysaccharide from the root of Bupleurum Chinese DC and Bupleurum scorzonerifolium Willd on hydrogen peroxide-induced myocardial apoptosis
Purpose: To investigate the protective effect of polysaccharide (BRP) from the root of Bupleurum Chinese DC. and Bupleurum scorzonerifolium Willd. on cardiomyocyte cells.
Methods: Response surface methodology (RSM) based on Box-Behnken Design (BBD) was performed to optimize the extraction conditions for BRP. The effect of BRP on cardiomyocyte cell apoptosis was evaluated in H9c2 cells treated with hydrogen peroxide (H2O2). Cell viability was determined by CCK-8 assay, while oxidative stress levels in H9c2 cells, including lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT) and creatine kinase (CK) were determined using commercial kits following the manufacture’s instruction. mRNA expressions (caspase-3, caspase-8, caspase-9 and Fas) were determined by quantitative real time-polymerase chain reaction (RT-qPCR).
Results: The obtained optimal extraction conditions for BRP was as follows: extraction time (1.43 h), ratio of water to the raw material (30 mL/g) and extraction times (2 times). BRP (200, 400, 600 and 800 μg/mL) significantly increased the cell viability of H2O2 induced H9c2 cells (p < 0.05, p < 0.01, p < 0.01, p < 0.01, respectively). BRP (200, 400 and 800 μg/mL) significantly decreased LDH and CK levels (p < 0.01, p < 0.01, p < 0.01, respectively). However, BRP increased levels of SOD (200, 400 and 800 μg/mL, p < 0.05) and CAT (400 and 800 μg/mL, p < 0.05) in H9c2 cells. BRP significantly downregulated mRNA expressions of Caspase-3, Caspase-8, Caspase-9 and Fas (200, 400 and 800 μg/mL, p < 0.01) in H9c2 cells induced by H2O2.
Conclusion: BRP protects cardiomyocyte against apoptosis via inhibition of oxidative stress and mitochondria-mediated intrinsic apoptosis, and thus, may be potential therapeutic agent for the management of cardiovascular diseases.
Keywords: Bupleurum Chinese, Bupleurum scorzonerifolium Willd., Polysaccharide, Cardiomyocyte, Apoptosis, H9c2 cell, Biochemical parameter
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