604 research outputs found
Combined modal split and assignment model for the multimodal transportation network of the economic circle in China
Economic circles have been formed and developing in China. An economic circle consists of more than one closely adjoining central cities and their influence zones. It is always the major engine for the development of one country's economy and even for the world economy. A combined modal split and assignment model with deterministic travel demand is proposed for modelling passengersā choices of intercity bus and train which are two main competing modes in the multimodal transportation network of the economic circle. The generalized travel cost model of highway and railway are used incorporating travel time, ticket fare and passenger's discomfort. On the highway network, the interactions of private vehicles and intercity buses are asymmetric. Thus, a variational inequality formulation is proposed to describe the combined model. The streamlined diagonalization algorithm is presented to solve the combined model. The multimodal transportation network based on Yangtze River Delta economic circle is presented to illustrate the proposed method. The results show the efficiency of the proposed model.
First published online:Ā 27 Oct 201
The effects of aB-crystallin on mitochondrial death pathway during hydrogen peroxide induced apoptosis
aB-crystallin, a major small heat shock protein, has recently been shown to exert inhibitory effects on apoptosis, while the responsible mechanisms remain largely unknown. In the present study, we discovered that aB-crystallin protected mouse myoblast C2C12 cells against oxidative stress-induced apoptosis. During hydrogen peroxide-induced apoptosis, aBcrystallin showed that it decreased the redistribution level of phosphatidylserine (PS), reduced the release of cytochrome C and Smac/Diablo from mitochondria into cytoplasm, and decreased the cleavage of Bid. Interestingly, immunoprecipitation experiments with anti-aBcrystallin and anti-myc-tag antibodies demonstrated respectively an interaction between aBcrystallin and p53 during hydrogen peroxide induced apoptosis. Both the NH2-terminal and COOH-terminal regions of aB-crystallin could interact with p53, suggesting two domains of aB-crystallin are necessary for the interaction. Electrophoresis mobility shift assay (EMSA) and luciferase assay further demonstrated that aB-crystallin inhibited the upregulation of the DNA-binding, as well as the transactivation activity of p53 induced by hydrogen peroxide. Our results show that aB-crystallin has a protective role in oxidative stress induced apoptosis by interference with the mitochondrial death pathway
The K giant stars from the LAMOST survey data I: identification, metallicity, and distance
We present a support vector machine classifier to identify the K giant stars
from the LAMOST survey directly using their spectral line features. The
completeness of the identification is about 75% for tests based on LAMOST
stellar parameters. The contamination in the identified K giant sample is lower
than 2.5%. Applying the classification method to about 2 million LAMOST spectra
observed during the pilot survey and the first year survey, we select 298,036 K
giant candidates. The metallicities of the sample are also estimated with
uncertainty of \,dex based on the equivalent widths of Mg and iron lines. A Bayesian method is then developed to estimate the
posterior probability of the distance for the K giant stars, based on the
estimated metallicity and 2MASS photometry. The synthetic isochrone-based
distance estimates have been calibrated using 7 globular clusters with a wide
range of metallicities. The uncertainty of the estimated distance modulus at
\,mag, which is the median brightness of the K giant sample, is about
0.6\,mag, corresponding to % in distance. As a scientific verification
case, the trailing arm of the Sagittarius stream is clearly identified with the
selected K giant sample. Moreover, at about 80\,kpc from the Sun, we use our K
giant stars to confirm a detection of stream members near the apo-center of the
trailing tail. These rediscoveries of the features of the Sagittarius stream
illustrate the potential of the LAMOST survey for detecting substructures in
the halo of the Milky Way.Comment: 24 pages, 20 figures, submitted to Ap
MassJoin: A mapreduce-based method for scalable string similarity joins
AbstractāString similarity join is an essential operation in data integration. The era of big data calls for scalable algorithms to support large-scale string similarity joins. In this paper, we study scalable string similarity joins using MapReduce. We propose a MapReduce-based framework, called MASSJOIN, which supports both set-based similarity functions and character-based similarity functions. We extend the existing partition-based signature scheme to support set-based similarity functions. We utilize the signatures to generate key-value pairs. To reduce the transmission cost, we merge key-value pairs to significantly reduce the number of key-value pairs, from cubic to linear com-plexity, while not sacrificing the pruning power. To improve the performance, we incorporate ālight-weight ā filter units into the key-value pairs which can be utilized to prune large number of dissimilar pairs without significantly increasing the transmission cost. Experimental results on real-world datasets show that our method significantly outperformed state-of-the-art approaches. I
Immunosuppressive effect of voacamine from Voacanga africana Stapf based on SPRi experiment
Purpose: To investigate the affinity of a bis-indole alkaloid - voacamine from Voacanga Africana Stapf for IL-2RĪ± - and its immunosuppressive effect on concanavalin A-induced T cell proliferation and lipopolysaccharide -induced B cell proliferation in vitro.
Methods: Surface plasmon resonance imaging (SPRi) was used to screen the target protein of voacamine, while CCK-8 kit was used to evaluate cytotoxicity. Mitogen-induced proliferation assay was carried out to assess the inhibitory effect of voacamine on Con A-induced T cell proliferation and LPSinduced B cell proliferation. The binding characteristics of voacamine were investigated using a binding model with IL-2RĪ± constructed based on molecular docking simulation.
Results: Voacamine had a high-affinity for IL-2RĪ± with an equilibrium dissociation constant (KD) of 1.85Ć10-8 M. Cytotoxicity data showed that voacamine did not exhibit cytotoxicity at concentrations lower than 0.32 ĀµM. However, it exerted significant immunosuppressive effect on B cells at a lower concentration, but had no influence on proliferation of T cells. Autodock results indicate that voacamine has a good interaction with the enzyme active site.
Conclusion: Voacamine and its analogues exert influence on the immune system
The site conditions of the Guo Shou Jing Telescope
The weather at Xinglong Observing Station, where the Guo Shou Jing Telescope
(GSJT) is located, is strongly affected by the monsoon climate in north-east
China. The LAMOST survey strategy is constrained by these weather patterns. In
this paper, we present a statistics on observing hours from 2004 to 2007, and
the sky brightness, seeing, and sky transparency from 1995 to 2011 at the site.
We investigate effects of the site conditions on the survey plan. Operable
hours each month shows strong correlation with season: on average there are 8
operable hours per night available in December, but only 1-2 hours in July and
August. The seeing and the sky transparency also vary with seasons. Although
the seeing is worse in windy winters, and the atmospheric extinction is worse
in the spring and summer, the site is adequate for the proposed scientific
program of LAMOST survey. With a Monte Carlo simulation using historical data
on the site condition, we find that the available observation hours constrain
the survey footprint from 22h to 16h in right ascension; the sky brightness
allows LAMOST to obtain the limit magnitude of V = 19.5mag with S/N = 10.Comment: 10 pages, 8 figures, accepted for publication in RA
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