7,039 research outputs found

    Angiogenesis and Vasculogenesis at 7-Day of Reperfused Acute Myocardial Infarction

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    Objectives 
This study is to investigate the angiogenesis and vasculogenesis at the first week of reperfused acute myocardial infarction (AMI).
Methods 
16 of mini-swines (20 to 30 Kg) were randomly assigned to the sham-operated group and the AMI group. The acute myocardial infarction and reperfusion model was created and the pig tail catheter was performed to monitor hemodynamics before left anterior descending coronary artery (LAD) occlusion, 90 min of LAD occlusion and 120 min of LAD reperfusion. Pathologic myocardial tissue was collected at 7-day of LAD reperfusion and further assessed by immunochemistry, dual immunochemistry, in-situ hybridization, real-time quantitative polymerase chain reaction and western blot. 
Results 
The infarcted area had higher FLK1 mRNA expression than sham-operated area and the normal area (all P<0.05), and the infarcted and marginal areas showed higher CD146 protein expression than the sham-operated area (all P<0.05), but the microvessel density (CD31 positive expression of microvessels/HP) was not significantly different between the infarcted area and the sham-operated area (8.92±3.05 vs 6.43±1.54) at 7-day of reperfused acute myocardial infarction (P>0.05). 
Conclusions 
FLK1 and CD146 expression significantly increase in the infarcted and marginal areas, and the microvessel density is not significantly different between the infarcted area and the sham-operated area, suggesting that angiogenesis and vasculogenesis in the infarcted area appear to high frequency of increase in 7-day of reperfused myocardial infarction. 
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    Silencing of two insulin receptor genes disrupts nymph-adult transition of alate brown citrus aphid

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    Insulin receptors play key roles in growth, development, and polymorphism in insects. Here, we report two insulin receptor genes (AcInR1 and AcInR2) from the brown citrus aphid, Aphis (Toxoptera) citricidus. Transcriptional analyses showed that AcInR1 increased during the nymph-adult transition in alate aphids, while AcInR2 had the highest expression level in second instar nymphs. AcInR1 is important in aphid development from fourth instar nymphs to adults as verified by dsRNA feeding mediated RNAi. The silencing of AcInR1 or/and AcInR2 produced a variety of phenotypes including adults with normal wings, malformed wings, under-developed wings, and aphids failing to develop beyond the nymphal stages. Silencing of AcInR1 or AcInR2 alone, and co-silencing of both genes, resulted in 73% or 60%, and 87% of aphids with problems in the transition from nymph to normal adult. The co-silencing of AcInR1 and AcInR2 resulted in 62% dead nymphs, but no mortality occurred by silencing of AcInR1 or AcInR2 alone. Phenotypes of adults in the dsInR1 and dsInR2 were similar. The results demonstrate that AcInR1 and AcInR2 are essential for successful nymph-adult transition in alate aphids and show that RNAi methods may be useful for the management of this pest

    Bacterial Cellulose for Skin Repair Materials

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    Peer Migration in China

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    We aim to quantify the role of social networks in job-related migration. With over 130 million rural labors migrating to the city each year, China is experiencing the largest internal migration in the human history. Using instrumental variables in the 2006 China Agricultural Census, we find that a 10-percentage-point increase in the migration rate of co-villagers raises one's migration probability by 7.27 percent points, an effect comparable to an increase of education by 7-8 years. Evidence suggests that most of this effect is driven by co-villagers helping each other in moving cost and job search at the destination.

    Probing new physics from top quark FCNC processes at linear colliders : a mini review

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    We briefly review the studies on the top quark FCNC processes at a next-generation linear collider. Such processes, including various FCNC top quark rare decays and top-charm associated productions, are extremely suppressed in the standard model (SM) but could be significantly enhanced in some extensions. We compared the predictions from different typical new physics models: the SM, the minimal supersymmetric model (MSSM), the general two-higgs-doublet model (2HDM) and the topcolor-assisted technicolor (TC2) model. Our conclusion is: (1) While all the new physics models can enhance the rates by several orders relative to the SM predictions, the TC2 model predicts much larger rates than other models; (2) The optimal channel for probing the top quark FCNC is the top-charm associated production in \gamma-\gamma collision, which occurs at a much higher rate than e^+ e^- or e^- \gamma collision and can reach the detectable level for a large part of the parameter space.Comment: 12 pages, 12 figs, talk given at APPI2004, Iweta, Japa

    The K giant stars from the LAMOST survey data I: identification, metallicity, and distance

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    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 0.130.290.13\sim0.29\,dex based on the equivalent widths of Mgb_{\rm b} 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 K=11K=11\,mag, which is the median brightness of the K giant sample, is about 0.6\,mag, corresponding to 30\sim30% 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

    Production of htt_bar and htT_bar in littlest Higgs model with T-parity

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    In the littlest Higgs model with T-parity, which predicts a pair of T-even and T-odd partners for the top quark, the top quark interactions are altered with respect to the Standard Model predictions and deviation will manifest in various top quark processes. In this work we examine the effects in htt_bar productions at the ILC and LHC. We find that in the allowed parameter space, the cross sections can be significantly deviated from the Standard Model predictions and thus provide a good test for the littlest Higgs model with T-parity. We also examine the new production channel, the htT_bar or hTt_bar production, at the LHC, which give the same final states as htt_bar production due to the dominant decay T->Wb. We find that, compared with htt_bar production, this new production channel can have a sizable production rate for a T-quark below TeV scale. Such a production will be counted into htt_bar events or possibly extracted from htt_bar events, depending on if we can distinguish the T-quark from the top quark from mass reconstructions.Comment: version in PRD (11 pages, 6 figs
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