Incident angle dependence of reactions between graphene and hydrogen atom by molecular dynamics simulation

Incident angle dependence of reactions between graphene and hydrogen atoms are obtained qualitatively by classical molecular dynamics simulation under the NVE condition with modified Brenner reactive empirical bond order (REBO) potential. Chemical reaction depends on two parameters, i.e., polar angle $\theta$ and azimuthal angle $\phi$ of the incident hydrogen. From the simulation results, it is found that the reaction rates strongly depend on polar angle $\theta$. Reflection rate becomes larger with increasing $\theta$, and the $\theta$ dependence of adsorption rate is also found. The $\theta$ dependence is caused by three dimensional structure of the small potential barrier which covers adsorption sites. $\phi$ dependence of penetration rate is also found for large $\theta$.Comment: 4 pages, 7 figure

Hybrid Simulation between Molecular Dynamics and Binary Collision Approximation Codes for Hydrogen injection onto Carbon Materials

Molecular dynamics (MD) simulation with modified Brenner's reactive empirical bond order (REBO) potential is a powerful tool to investigate plasma wall interaction on divertor plates in a nuclear fusion device. However, MD simulation box's size is less than several nm for the performance of a computer. To extend the size of the MD simulation, we develop a hybrid simulation code between MD code using REBO potential and binary collision approximation (BCA) code. Using the BCA code instead of computing all particles with a high kinetic energy for every step in the MD simulation, considerable computation time is saved. By demonstrating a hydrogen atom injection on a graphite by the hybrid simulation code, it is found that the hybrid simulation code works efficiently in a large simulation box.Comment: 5 pages, 5 figure

Molecular Dynamics Simulation of Chemical Vapor Deposition of Amorphous Carbon: Dependence on H/C Ratio of Source Gas

By molecular dynamics simulation, the chemical vapor deposition of amorphous carbon onto graphite and diamond surfaces was studied. In particular, we investigated the effect of source H/C ratio, which is the ratio of the number of hydrogen atoms to the number of carbon atoms in a source gas, on the deposition process. In the present simulation, the following two source gas conditions were tested: one was that the source gas was injected as isolated carbon and hydrogen atoms, and the other was that the source gas was injected as hydrocarbon molecules. Under the former condition, we found that as the source H/C ratio increases, the deposition rate of carbon atoms decreases exponentially. This exponential decrease in the deposition rate with increasing source H/C ratio agrees with experimental data. However, under the latter molecular source condition, the deposition rate did not decrease exponentially because of a chemical reaction peculiar to the type of hydrocarbon in the source gas.Comment: accepted by Jpn. J. Appl. Phys. (2008

Effect of Weight Loss Prior to Cold Strage on Chilling Sensitivity in Eggplant Fruit

ナス果実を2%までの範囲で種々の程度の減量処理を行った後,5℃で7日間の低温貯蔵を行い,その後20℃又は25℃に昇温してピッティング発生及び鮮度変化を調査した. さらに,減量後に吸水によって重量を復元させた後,同様の調査を行った. その結果,低温貯蔵前に0.5%程度減量させることによって,低温障害抑制効果が認められた. この効果は,減量後吸水によって重量を復元してもなお継続して認められた. 1%以上の減量を行うと障害抑制効果はみられなくなった. 1%又は2%減量後に吸水復元させると,0.5%減量までの復元で,障害発生はある程度抑制される傾向がみられた. このようなことから,ナス果実では低温貯蔵前の軽い水分減少は低温耐性を高くする方向に作用すること,低温耐性は単に含水量だけではなく,組織間の水の動きに密接に関係していることが推察された

Can the liver with Gilbert's syndrome be used as graft of living-related liver transplantation?

Gilbert’s syndrome is the common cause of non hemolytic unconjugated hyperbilirubinemia with a prevalance of 3～7%. Gilbert’s syndrome may introduce a selection of potential liver donors from brain death patients. We present a case of living-related liver transplantation (LRLT) from a donor with Gilbert’s syndrome. A 22-year-old woman had been diagnosed as having liver cirrhosis at the age of 5. She underwent liver transplantation with the donor’s left lobe as the graft. The donor, who was the father of the patient, had been diagnosed with Gilbert’s syndrome. Although the recipient was well until 11 months after surgery, she died of subacute fulminant hepatitis 16 months after surgery. However, it was clear that the liver with Gilbert’s syndrome could be used as a graft of living-related liver transplantation for adult recipients

Hepatopulmonary syndrome-discussion of cardiopulmonary parameters

We report a 70-year-old man with hepatopulmonary syndrome (HPS) in C liver cirrhosis. Hypoxemia worsened markedly, especially on exertion, while the hepatic function was clinically stable. Contrast echocardiography, 99mTc macroaggregated albumin (99mTcMAA) lung scan, and pulmonary angiography were performed. The findings suggested the presence of both intrapulmonary vascular dilatation and substantial right-to-left shunt. The contribution of intrapulmonary vascular abnormalities in patients with severe liver cirrhosis without abnormal chest radiography and spirometry tests when marked hypoxemia is present should be investigated

Enhancement of protein production via the strong DIT1 terminator and two RNA-binding proteins in Saccharomyces cerevisiae

Post-transcriptional upregulation is an effective way to increase the expression of transgenes and thus maximize the yields of target chemicals from metabolically engineered organisms. Refractory elements in the 3′ untranslated region (UTR) that increase mRNA half-life might be available. In Saccharomyces cerevisiae, several terminator regions have shown activity in increasing the production of proteins by upstream coding genes; among these terminators the DIT1 terminator has the highest activity. Here, we found in Saccharomyces cerevisiae that two resident trans-acting RNA-binding proteins (Nab6p and Pap1p) enhance the activity of the DIT1 terminator through the cis element GUUCG/U within the 3′-UTR. These two RNA-binding proteins could upregulate a battery of cell-wall–related genes. Mutagenesis of the DIT1 terminator improved its activity by a maximum of 500% of that of the standard PGK1 terminator. Further understanding and improvement of this system will facilitate inexpensive and stable production of complicated organism-derived drugs worldwide

c-Axis Transport and Resistivity Anisotropy of Lightly- to Moderately-Doped La_{2-x}Sr_{x}CuO_{4} Single Crystals: Implications on the Charge Transport Mechanism

Both the in-plane and the out-of-plane resistivities (\rho_{ab} and \rho_{c}) are measured in high-quality La_{2-x}Sr_{x}CuO_{4} (LSCO) single crystals in the lightly- to moderately-doped region, x = 0.01 to 0.10, and the resistivity anisotropy is determined. In all the samples studied, the anisotropy ratio \rho _{c}/\rho_{ab} quickly increases with decreasing temperature, although in non-superconducting samples the strong localization effect causes \rho _{c}/\rho_{ab} to decrease at low temperatures. Most notably, it is found that \rho_{c}/\rho_{ab} at moderate temperatures (100 - 300 K) is almost completely independent of doping in the non-superconducting regime (x = 0.01 to 0.05); this indicates that the same charge confinement mechanism that renormalizes the c-axis hopping rate is at work down to x = 0.01. It is discussed that this striking x-independence of \rho_{c}/\rho_{ab} is consistent with the idea that holes form a self-organized network of hole-rich regions, which also explains the unusually metallic in-plane transport of the holes in the lightly-doped region. Furthermore, the data for x > 0.05 suggest that the emergence of the superconductivity is related to an increase in the c-axis coupling.Comment: 7 pages, 5 figures, submitted to Phys. Rev.