1,266 research outputs found
Design, Modeling, Microfabrication and Characterization of the Micro Gas Chromatography Columns
Varied Signature Splitting Phenomena in Odd Proton Nuclei
Varied signature splitting phenomena in odd proton rare earth nuclei are
investigated. Signature splitting as functions of and in the angular
momentum projection theory is explicitly shown and compared with those of the
particle rotor model. The observed deviations from these rules are due to the
band mixings. The recently measured Ta high spin data are taken as a
typical example where fruitful information about signature effects can be
extracted. Six bands, two of which have not yet been observed, were calculated
and discussed in detail in this paper. The experimentally unknown band head
energies are given
Temperature dependence of current self-oscillations and electric field domains in sequential tunneling doped superlattices
We examine how the current--voltage characteristics of a doped weakly coupled
superlattice depends on temperature. The drift velocity of a discrete drift
model of sequential tunneling in a doped GaAs/AlAs superlattice is calculated
as a function of temperature. Numerical simulations and theoretical arguments
show that increasing temperature favors the appearance of current
self-oscillations at the expense of static electric field domain formation. Our
findings agree with available experimental evidence.Comment: 7 pages, 5 figure
Optimization of protein extraction from tree peony (Paeonia suffruticosa Andr.) seed using response surface methodology
Optimization of extraction ratio (ER) of tree peony seed protein (TPSP) was investigated using response surface methodology (RSM). The second-degree equation for ER of TPSP had high coeffi cient (0.9625) of determination. The probability (P) value of regression model signifi cance was less than 0.001 by analysis of central composite rotatable design. Relationships of ER to pH, liquid/solid ratio, squares of all factors, and cross-product factors (x2x3, x2x4, x3x4) were signifi cant (P1x2, x1x3, x1x4) were not signifi cant factors (P>0.05). Optimum extraction conditions were 3.42 h, pH 9.50, 50.80 ºC, and 9.54 ml g–1 of liquid/solid ratio with the maximum ER (43.60%) . SDS-PAGE indicated TPSP had mainly four proteins (180, 100, 60, and 35 kDa) with four subunits of 60, 48, 38, and 23 kDa. TPSP had a good amino acid composition with abundant essential amino acids (39.76%) determined by amino acid analysis
SORLA attenuates EphA4 signaling and amyloid, β-induced neurodegeneration
Sortilin-related receptor with LDLR class A repeats (SORLA, SORL1, or LR11) is a genetic risk factor associated with Alzheimer's disease (AD). Although SORLA is known to regulate trafficking of the amyloid {beta} (A{beta}) precursor protein to decrease levels of proteotoxic A{beta} oligomers, whether SORLA can counteract synaptic dysfunction induced by A{beta} oligomers remains unclear. Here, we show that SORLA interacts with the EphA4 receptor tyrosine kinase and attenuates ephrinA1 ligand-induced EphA4 clustering and activation to limit downstream effects of EphA4 signaling in neurons. Consistent with these findings, SORLA transgenic mice, compared with WT mice, exhibit decreased EphA4 activation and redistribution to postsynaptic densities, with milder deficits in long-term potentiation and memory induced by A{beta} oligomers. Importantly, we detected elevated levels of active EphA4 in human AD brains, where EphA4 activation is inversely correlated with SORLA/EphA4 association. These results demonstrate a novel role for SORLA as a physiological and pathological EphA4 modulator, which attenuates synaptotoxic EphA4 activation and cognitive impairment associated with A{beta}-induced neurodegeneration in AD
Specific heat of quasi-2D antiferromagnetic Heisenberg models with varying inter-planar couplings
We have used the stochastic series expansion (SSE) quantum Monte Carlo (QMC)
method to study the three-dimensional (3D) antiferromagnetic Heisenberg model
on cubic lattices with in-plane coupling J and varying inter-plane coupling
J_perp < J. The specific heat curves exhibit a 3D ordering peak as well as a
broad maximum arising from short-range 2D order. For J_perp << J, there is a
clear separation of the two peaks. In the simulations, the contributions to the
total specific heat from the ordering across and within the layers can be
separated, and this enables us to study in detail the 3D peak around T_c (which
otherwise typically is dominated by statistical noise). We find that the peak
height decreases with decreasing J_perp, becoming nearly linear below J_perp =
0.2J. The relevance of these results to the lack of observed specific heat
anomaly at the ordering transition of some quasi-2D antiferromagnets is
discussed.Comment: 7 pages, 8 figure
Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-
We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi -->
D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7
J/Psi events collected with the BESII detector at the BEPC. No excess of signal
above background is observed, and 90% confidence level upper limits on the
branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi
--> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
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