The expression patterns of three VRN genes in common wheat (Triticum aestivum L.) in response to vernalization

Common wheat is a widely planted cereal in China, and vernalization is a crucial phase in wheat development. Although three major genes (VRN1, VRN2 and VRN3) are associated with the vernalization response, little is known about their expression profiles during wheat growth. In this study, we observed the spike differentiation process in spring wheat variety XC2 and winter wheat variety J841 and used qRT-PCR to analyze the expression patterns of three VRN genes in the leaves of these wheat varieties during development under vernalization versus non-vernalization treatment under long-day conditions. We also analyzed the expression patterns of VRN1 and VRN3 in the apical meristem. In both spring and winter wheat, the spikes remained at the single ridge state and did not differentiate under vernalization treatment. Spike differentiation completed one week earlier in XC2 spring wheat after vernalization treatment compared with non-vernalization conditions. Vernalization treatment significantly upregulated VRN1 and VRN3 expression in leaves under long-day conditions, whereas VRN2 expression was sharply reduced. The expression of VRN3 was low in shoot apical meristems, while VRN1 was highly expressed in shoot apical meristems when floral primordia began to differentiate and develop, suggesting that VRN1 functions independently in leaves and shoot apical meristems

Stability of multi-electron bubbles in liquid helium

The stability of multi-electron bubbles in liquid helium is investigated theoretically. We find that multi-electron bubbles are unstable against fission whenever the pressure is positive. It is shown that for moving bubbles the Bernoulli effect can result in a range of pressures over which the bubbles are stable.Comment: 7 pages, 5 figure

Empirical study on clique-degree distribution of networks

The community structure and motif-modular-network hierarchy are of great importance for understanding the relationship between structures and functions. In this paper, we investigate the distribution of clique-degree, which is an extension of degree and can be used to measure the density of cliques in networks. The empirical studies indicate the extensive existence of power-law clique-degree distributions in various real networks, and the power-law exponent decreases with the increasing of clique size.Comment: 9 figures, 4 page

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

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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Evolution of electronic states in n-type copper oxide superconductor via electric double layer gating

Since the discovery of n-type copper oxide superconductors, the evolution of electron- and hole-bands and its relation to the superconductivity have been seen as a key factor in unveiling the mechanism of high-Tc superconductors. So far, the occurrence of electrons and holes in n-type copper oxides has been achieved by chemical doping, pressure, and/or deoxygenation. However, the observed electronic properties are blurred by the concomitant effects such as change of lattice structure, disorder, etc. Here, we report on successful tuning the electronic band structure of n-type Pr2-xCexCuO4 (x = 0.15) ultrathin films, via the electric double layer transistor technique. Abnormal transport properties, such as multiple sign reversals of Hall resistivity in normal and mixed states, have been revealed within an electrostatic field in range of -2 V to +2 V, as well as varying the temperature and magnetic field. In the mixed state, the intrinsic anomalous Hall conductivity invokes the contribution of both electron and hole-bands as well as the energy dependent density of states near the Fermi level. The two-band model can also describe the normal state transport properties well, whereas the carrier concentrations of electrons and holes are always enhanced or depressed simultaneously in electric fields. This is in contrast to the scenario of Fermi surface reconstruction by antiferromagnetism, where an anti-correlation between electrons and holes is commonly expected. Our findings paint the picture where Coulomb repulsion plays an important role in the evolution of the electronic states in n-type cuprate superconductors.Comment: 4 figures, SI not included. Comments are welcom

Understanding Oxidative Instability of Protein Pharmaceuticals

Mechanism of oxidation of methionine residues in protein pharmaceuticals by hydrogen peroxide was investigated via ab initio calculations. Specifically, two reactions, hydrogen transfer of hydrogen peroxide to form water oxide and the oxidation of dimethyl sulfide (DMS) by hydrogen peroxide to form dimethyl sulfoxide, were studied as models of these processes in general. Solvent effects are included both via including explicitly water molecules and via the polarizable continuum model. Specific interactions including hydrogen bonding with 2-3 water molecules can provide enough stabilization for the charge separation at the activation complex. The major reaction coordinates of the reaction are the breaking of the O-O bond of H₂O₂ and the formation of the S-O bond, the transfer of hydrogen to the distal oxygen of hydrogen peroxide occurring after the system has passed the transition state. Reaction barriers of the hydrogen transfer of H₂O₂ are in average of 10 kcal/mol or higher than the oxidation of DMS. Therefore, a two step oxidation mechanism in which the transfer of hydrogen atom occurs first to form water oxide and the transfer of oxygen to substrate occurs as the second step, is unlikely to be correct. Our proposed oxidation mechanism does not suggest pH dependence of oxidation rate within a moderate range around neutral pH (i.e. under conditions in which hydronium and hydroxide ions do not participate directly in the reaction), and it agrees with experimental observations over moderate pH values.Singapore-MIT Alliance (SMA

On the Oxidation of Methionine Residues during the Storage of Protein Pharmaceuticals in an Aqueous Formulation

This study addresses the fundamentals of an important degradation pathway of storing protein pharmaceuticals in an aqueous formulation, oxidation of methionine residues by peroxides. First, a mechanism by which methionine residues are oxidized is identified via ab initio calculations. The major difference of this new mechanism to previous ones is the role of solvent molecules in the oxidation process. Previously proposed mechanisms suggested that solvent molecules facilitate the transfer of hydrogen associated with the oxidation reaction, but the estimated activation energies and pH dependence of oxidation rates derived from this mechanism rates do not agree with experimental observations. In our proposed mechanism, however, water molecules stabilize the charge separation in the transition-state complex through specific interaction such as hydrogen bonding. This mechanism satisfies all experimental studies on the oxidation of organic sulfides by peroxides. A correct picture of instability mechanism is essential in developing stabilization strategies to design a robust formulation. Based on this mechanism, a structure/instability relationship is built to explain the oxidation rates of methionine residues in a protein molecule. Specifically, a structural property, two-shell water coordination number, is found to correlate semi-quantitatively to the rates of oxidation of methionine residues in G-CSF (granulocyte colony-stimulating factor) and hPTH (human parathoid hormone). We also show that a traditionally used structural property, solvent accessible area, can not provide such accurate correlation and that the dynamic motion of protein molecules and an explicit treatment of solvent molecules are essential to describe the rates of oxidation of methionine residues. Furthermore, the insight provided by the molecule-level understanding in developing a stabilizing formulation is discussed.Singapore-MIT Alliance (SMA