632 research outputs found
Quantum switch for single-photon transport in a coupled superconducting transmission line resonator array
We propose and study an approach to realize quantum switch for single-photon
transport in a coupled superconducting transmission line resonator (TLR) array
with one controllable hopping interaction. We find that the single-photon with
arbitrary wavevector can transport in a controllable way in this system. We
also study how to realize controllable hopping interaction between two TLRs via
a superconducting quantum interference device (SQUID). When the frequency of
the SQUID is largely detuned from those of the two TLRs, the variables of the
SQUID can be adiabatically eliminated and thus a controllable interaction
between two TLRs can be obtained.Comment: 4 pages,3 figure
Structural Evolution of Early-type Galaxies to z=2.5 in CANDELS
Projected axis ratio measurements of 880 early-type galaxies at redshifts
1<z<2.5 selected from CANDELS are used to reconstruct and model their intrinsic
shapes. The sample is selected on the basis of multiple rest-frame colors to
reflect low star-formation activity. We demonstrate that these galaxies as an
ensemble are dust-poor and transparent and therefore likely have smooth light
profiles, similar to visually classified early-type galaxies. Similar to their
present-day counterparts, the z>1 early-type galaxies show a variety of
intrinsic shapes; even at a fixed mass, the projected axis ratio distributions
cannot be explained by the random projection of a set of galaxies with very
similar intrinsic shapes. However, a two-population model for the intrinsic
shapes, consisting of a triaxial, fairly round population, combined with a flat
(c/a~0.3) oblate population, adequately describes the projected axis ratio
distributions of both present-day and z>1 early-type galaxies. We find that the
proportion of oblate versus triaxial galaxies depends both on the galaxies'
stellar mass, and - at a given mass - on redshift. For present-day and z<1
early-type galaxies the oblate fraction strongly depends on galaxy mass. At z>1
this trend is much weaker over the mass range explored here
(10^10<M*/M_sun<10^11), because the oblate fraction among massive (M*~10^11
M_sun) was much higher in the past: 0.59+-0.10 at z>1, compared to 0.20+-0.02
at z~0.1. In contrast, the oblate fraction among low-mass early-type galaxies
(log(M*/M_sun)1 to
0.72+-0.06 at z=0. [Abridged]Comment: accepted for publication in ApJ; 14 pages; 10 figures; 4 table
Gluonic and leptonic decays of heavy quarkonia and the determination of and
QCD running coupling constant and are
determined from heavy quarkonia and decays. The
decay rates of and for and
are estimated by taking into account both relativistic and QCD
radiative corrections. The decay amplitudes are derived in the Bethe-Salpeter
formalism, and the decay rates are estimated by using the meson wavefunctions
which are obtained with a QCD-inspired inter-quark potential. For the
decay we find the relativistic correction to be very large
and to severely suppress the decay rate. Using the experimental values of ratio
R_g\equiv \frac {\Gamma (V\longrightarrow 3g)}% {\Gamma (V\longrightarrow
e^{+}e^{-})}\approx 10,~32 for respectively, and the
calculated widths , we find and
. These values for the QCD running coupling
constant are substantially enhanced, as compared with the ones obtained without
relativistic corrections, and are consistent with the QCD scale parameter
. We also find that these
results are mainly due to kinematic corrections and not sensitive to the
dynamical models.Comment: 15 pages in Late
Hypermethylation of the TGF-β target, ABCA1 is associated with poor prognosis in ovarian cancer patients
Background
The dysregulation of transforming growth factor-β (TGF-β) signaling plays a crucial role in ovarian carcinogenesis and in maintaining cancer stem cell properties. Classified as a member of the ATP-binding cassette (ABC) family, ABCA1 was previously identified by methylated DNA immunoprecipitation microarray (mDIP-Chip) to be methylated in ovarian cancer cell lines, A2780 and CP70. By microarray, it was also found to be upregulated in immortalized ovarian surface epithelial (IOSE) cells following TGF-β treatment. Thus, we hypothesized that ABCA1 may be involved in ovarian cancer and its initiation.
Results
We first compared the expression level of ABCA1 in IOSE cells and a panel of ovarian cancer cell lines and found that ABCA1 was expressed in HeyC2, SKOV3, MCP3, and MCP2 ovarian cancer cell lines but downregulated in A2780 and CP70 ovarian cancer cell lines. The reduced expression of ABCA1 in A2780 and CP70 cells was associated with promoter hypermethylation, as demonstrated by bisulfite pyro-sequencing. We also found that knockdown of ABCA1 increased the cholesterol level and promoted cell growth in vitro and in vivo. Further analysis of ABCA1 methylation in 76 ovarian cancer patient samples demonstrated that patients with higher ABCA1 methylation are associated with high stage (P = 0.0131) and grade (P = 0.0137). Kaplan-Meier analysis also found that patients with higher levels of methylation of ABCA1 have shorter overall survival (P = 0.019). Furthermore, tissue microarray using 55 ovarian cancer patient samples revealed that patients with a lower level of ABCA1 expression are associated with shorter progress-free survival (P = 0.038).
Conclusions
ABCA1 may be a tumor suppressor and is hypermethylated in a subset of ovarian cancer patients. Hypermethylation of ABCA1 is associated with poor prognosis in these patients
Nanocomposite ZnO–SnO2 Nanofibers Synthesized by Electrospinning Method
We report the characterization of mixed oxides nanocomposite nanofibers of (1 − x) ZnO-(x)SnO2 (x ≤ 0.45) synthesized by electrospinning technique. The diameter of calcined nanofibers depends on Sn content. Other phases like SnO, ZnSnO3, and Zn2SnO4 were absent. Photoluminescence studies show that there is a change in the blue/violet luminescence confirming the presence of Sn in Zn-rich composition. Present study shows that the crystalline nanocomposite nanofibers with stoichiometry of (1 − x)ZnO-(x)SnO2 (x ≤ 0.45) stabilize after the calcination and possess some morphological and optical properties that strongly depend on Sn content
Neutron radius determination of 133Cs and its impact on the interpretation of CEvNS-CsI measurement
Proton-Cs elastic scattering at low momentum transfer is performed
using an in-ring reaction technique at the Cooler Storage Ring at the Heavy Ion
Research Facility in Lanzhou. Recoil protons from the elastic collisions
between the internal H-gas target and the circulating Cs ions at
199.4 MeV/u are detected by a silicon-strip detector. The matter radius of
Cs is deduced by describing the measured differential cross sections
using the Glauber model. Employing the adopted proton distribution radius, a
point-neutron radius of 4.86(21) fm for Cs is obtained. With the newly
determined neutron radius, the weak mixing angle sin is
independently extracted to be 0.227(28) by fitting the coherent elastic
neutrino-nucleus scattering data. Our work limits the sin value in
a range smaller than the ones proposed by the previous independent approaches,
and would play an important role in searching new physics via the high
precision CENS-CsI cross section data in the near future
Experimental study on flexural behaviours of fresh or aged hollow reinforced concrete girders strengthened by prestressed CFRP plates
The paper presents a well-rounded experimental study on the flexural performance of Reinforced Concrete (RC) box girders strengthened with prestressed carbon fibre reinforced polymer (CFRP) plates. The motivation behind the study was twofold: the rising need for structural reinforcement of existing aged and heavily utilised hollow RC box girders, and the absence of prior attempts to integrate prestressed CFRP plate strengthening for those hollow girders. Previous experimental studies are scarce and fewer studies are focused on the combined prestress and thin-wall effects, such as prestress-related stress condensation and shear lag. However, experimental results are important in directing further analytical studies for hollow sections with more complex behaviours than solid sections since there is a need to predict the behaviour of the prestress-strengthened hollow RC structures for routine design. This pivotal experimental study aims to quantify the structural interactions initiated by prestress in hollow sections and evaluate the impact of age while promoting further analytical initiatives. In this study, two types of CFRP plates, ordinary CFRP and steel-wire-CFRP (SW-CFRP), were used on different specimen beams with varying prestressing levels, sizes of the CFRP plates, and pre-damaged states representing aged and over-used members. Their performance indexes, including cracking load, yield load, ultimate load, structural stiffness, ductility, and crack resistance, were tested and summarised in this paper. The CFRP plates of the eight specimen beams were prestressed to different levels (non-prestressed, and 30% and 40% of the CFRP plate's ultimate strength). The test results suggest that the crack load increased by 86% and 134%, when the specimens were enhanced with the combinations of 30% prestress level for the same CFRP cross-section, and 40% prestress level with a thicker CFRP plate, respectively. The flexural capacity also increased by 42% and 72%, and flexural stiffness increased by 3% and 63%, respectively. The experimental results proved that the proposed prestressed CFRP plate technology effectively strengthens the new or aged RC box girders, but the ductility is sacrificed. These first-hand test results provide an excellent target dataset for further development in the analysis and design of prestressed CFRP plate-strengthened RC box girders
\psi(2S) Decays into \J plus Two Photons
Using \gamma \gamma J/\psi, J/\psi \ra e^+ e^- and events
from a sample of \psip decays collected with the BESII
detector, the branching fractions for \psip\ra \pi^0\J, \eta\J, and
\psi(2S)\ar\gamma\chi_{c1},\gamma\chi_{c2}\ar\gamma\gamma\jpsi are measured
to be B(\psip\ra \pi^0\J) = (1.43\pm0.14\pm0.13)\times 10^{-3}, B(\psip\ra
\eta\J) = (2.98\pm0.09\pm0.23)%,
B(\psi(2S)\ar\gamma\chi_{c1}\ar\gamma\gamma\jpsi) = (2.81\pm0.05\pm 0.23)%,
and B(\psi(2S)\ar\gamma\chi_{c2}\ar\gamma\gamma\jpsi) = (1.62\pm0.04\pm
0.12)%.Comment: 7 pages, 6 figures. submitted to Phys. Rev.
Tonicity-responsive microRNAs contribute to the maximal induction of osmoregulatory transcription factor OREBP in response to high-NaCl hypertonicity
Osmotic response element binding protein (OREBP) is a Rel-like transcription factor critical for cellular osmoresponses. Previous studies suggest that hypertonicity-induced accumulation of OREBP protein might be mediated by transcription activation as well as posttranscriptional mRNA stabilization or increased translation. However, the underlying mechanisms remain incompletely elucidated. Here, we report that microRNAs (miRNAs) play critical regulatory roles in hypertonicity-induced induction of OREBP. In renal medullary epithelial mIMCD3 cells, hypertonicity greatly stimulates the activity of the 3′-untranslated region of OREBP (OREBP-3′UTR). Furthermore, overexpression of OREBP-3′UTR or depletion of miRNAs by knocking-down Dicer greatly increases OREBP protein expression. On the other hand, significant alterations in miRNA expression occur rapidly in response to high NaCl exposure, with miR-200b and miR-717 being most significantly down-regulated. Moreover, increased miR-200b or miR-717 causes significant down-regulation of mRNA, protein and transcription activity of OREBP, whereas inhibition of miRNAs or disruption of the miRNA–3′UTR interactions abrogates the silencing effects. In vivo in mouse renal medulla, miR-200b and miR-717 are found to function to tune OREBP in response to renal tonicity alterations. Together, our results support the notion that miRNAs contribute to the maximal induction of OREBP to participate in cellular responses to osmotic stress in mammalian renal cells
Purification and Characterization of Enterovirus 71 Viral Particles Produced from Vero Cells Grown in a Serum-Free Microcarrier Bioreactor System
[[abstract]]Background: Enterovirus 71 (EV71) infections manifest most commonly as a childhood exanthema known as hand-foot-and-mouth disease (HFMD) and can cause neurological disease during acute infection. Principal Finding: In this study, we describe the production, purification and characterization of EV71 virus produced from Vero cells grown in a five-liter serum-free bioreactor system containing 5 g/L Cytodex 1 microcarrier. The viral titer was >106 TCID50/mL by 6 days post infection when a MOI of 10?5 was used at the initial infection. Two EV71 virus fractions were separated and detected when the harvested EV71 virus concentrate was purified by sucrose gradient zonal ultracentrifugation. The EV71 viral particles detected in the 24–28% sucrose fractions had an icosahedral structure 30–31 nm in diameter and had low viral infectivity and RNA content. Three major viral proteins (VP0, VP1 and VP3) were observed by SDS-PAGE. The EV71 viral particles detected in the fractions containing 35–38% sucrose were 33–35 nm in size, had high viral infectivity and RNA content, and were composed of four viral proteins (VP1, VP2, VP3 and VP4), as shown by SDS-PAGE analyses. The two virus fractions were formalin-inactivated and induced high virus neutralizing antibody responses in mouse immunogenicity studies. Both mouse antisera recognized the immunodominant linear neutralization epitope of VP1 (residues 211–225). Conclusion:These results provide important information for cell-based EV71 vaccine development, particularly for the preparation of working standards for viral antigen quantification
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