日本锂离子蓄电池技术的开发过程和最新趋势

锂离子蓄电池已被广泛应用于蜂窝移动电话、笔记本电脑及摄录像一体机等便携式电器的电源。这种新型电池体系的研究和开发工作始于 1981年 ,其起源是对采用电子导电聚合物———聚乙炔作为负极材料的锂蓄电池的开发。此后 ,研究的重点从聚乙炔转移到具有同样的 pi电子的碳材料上。在含锂离子的金属氧化物LiCoO2 被采用为正极材料后 ,锂离子蓄电池终于开发成功。在锂离子蓄电池实现商品化生产后 ,许多相应的技术也被开发出来 ,而这些新技术将会提高锂离子蓄电池的性能。     

The Effects of Conventional Stabilizers and Phenol Compounds Used as Antioxidants on the Stabilization of Nitrocellulose

The thermal behavior of nitrocellulose (NC) containing diphenylamine (DPA), 2‐nitrodiphenylamine (2‐NO₂‐DPA), N‐nitrosodiphenylamine (N‐NO‐DPA), ethyl centralite (EC), akardite II (AKII), 1,1,3‐tri‐(2‐methyl‐4‐hydroxy‐5‐tert‐butyl‐phenyl)‐butane (BP_less), 3‐(3,5‐di‐tert‐butyl‐4‐hydroxy‐phenyl)‐propionic acid octadecyl ester (BP_hin), and 3‐(3‐tert‐butyl‐4‐hydroxy‐5‐methyl‐phenyl)‐propionic acid 2‐(9‐{2‐[3‐(3‐tert‐butyl‐4‐hydroxy‐5‐methyl‐phenyl)‐propionyloxy]‐1,1‐dimethyl‐ethyl}‐2,4,8,10‐tetraoxa‐spiro [5.5] undec‐3‐yl)‐2‐methyl‐propyl ester (BP_semi) was observed during isothermal storage at 393 K using a C80 microcalorimeter. The results indicate that each stabilizer decreased NC's maximum heat release rate and increased the induction period of heat release. We also observed that the maximum heat release rate and the induction period were dependent on the amount of stabilizer. DPA decreased the maximum heat release rate to the greatest extent, with the other stabilizers having similar effects on the decrease of maximum heat release rate. AKII prolonged the induction period of heat release most. The order of prolongation of the induction period was AKII>2‐NO₂‐DPA≈DPA>N‐NO‐DPA≈EC>BP_less≈BP_semi≈BP_hin.     

Alcohol dehydrogenases that catalyse methyl formate synthesis participate in formaldehyde detoxification in the methylotrophic yeast Candida boidinii

Methyl formate synthesis during growth on methanol by methylotrophic yeasts has been considered to play a role in formaldehyde detoxification. An enzyme that catalyses methyl formate synthesis was purified from methylotrophic yeasts, and was suggested to belong to a family of alcohol dehydrogenases (ADHs). In this study we report the gene cloning and gene disruption analysis of three ADH-encoding genes in the methylotrophic yeast Candida boidinii (CbADH1, CbADH2 and CbADH3) in order to clarify the physiological role of methyl formate synthesis. From the primary structures of these three genes, CbAdh1 was shown to be cytosolic and CbAdh2 and CbAdh3 were mitochondrial enzymes. Gene products of CbADH1, CbADH2 and CbADH3 expressed in Escherichia coli showed both ADH- and methyl formate-synthesizing activities. The results of gene-disruption analyses suggested that methyl formate synthesis was mainly catalysed by a cytosolic ADH (CbAdh1), and this enzyme contributed to formaldehyde detoxification through glutathione-independent formaldehyde oxidation during growth on methanol by methylotrophic yeasts.     

ST-segment elevation in right precordial leads implies depressed right ventricular function after acute inferior myocardial infarction

BACKGROUND: The prognosis of acute inferior myocardial infarction is worse when it is complicated by right ventricular infarction. ST elevation in the right precordial leads is one of the reliable methods for detecting acute right ventricular infarction. The purpose of the study was to examine the relation between ST elevation in the right precordial electrocardiographic leads during acute inferior infarction and the severity of right ventricular systolic dysfunction. METHODS: This study analyzed the relation between ST elevation > or = 0.1 mV in V4R and the severity of right ventricular systolic dysfunction in 43 consecutive patients (men/women: 35/8; average age 62+/-9 years) with acute inferior myocardial infarction with a rapid-response Swan-Ganz catheter to measure the right ventricular ejection fraction (RVEF). RESULTS: RVEF was significantly lower in patients with ST elevation (n = 18) than in those without (n = 25) (33%+/-6% vs 40%+/-9%, p = 0.010). If the infarct-related lesion was located in the proximal right coronary artery, RVEF tended to be lower than if the lesion was located in the distal right coronary artery or the left circumflex coronary artery (33%+/-10% vs 37%+/-9% vs 42%+/-9%, p = 0.101). Logistic regression analysis demonstrated that ST elevation in V4R was the only independent predictor of depressed RVEF (odds ratio = 5.31, 95% confidence interval = 1.28 to 22.1, p = 0.022). CONCLUSION: ST elevation in lead V4R during acute inferior myocardial infarction predicts right ventricular systolic dysfunction.     

Electrical characterization of high-k gate dielectrics on Ge with HfGeN and GeO2 interlayers

Two kinds of HfSiO_x/interlayers (ILs)/Ge gate stack structures with HfGeN- and GeO₂-ILs were fabricated using electron cyclotron resonance (ECR) plasma sputtering and the subsequent post deposition annealing (PDA). It was found that HfGe was formed by the deposition of Hf metal on Ge and changed to HfGeN by N₂ ECR-plasma irradiation, which was used as IL. Another IL was GeO₂, which was grown by thermal oxidation at 500 °C. For dielectrics with HfGeN-IL, PDA of 550 °C resulted in effective oxide thickness (EOT) of 2.2 nm, hysteresis of 0.1 V, and interface state density (D_it) = 7 × 10¹² cm^− 2 eV^− 1. For dielectrics with GeO₂-IL, PDA of 500 °C resulted in EOT of 2.8 nm, hysteresis of 0.1 V, and D_it = 1 × 10¹² cm^− 2 eV^− 1. The structural change of HfSiO_x/GeO₂/Ge during the PDA was clarified by using X-ray photoelectron spectroscopy, and the gate stack formation for obtaining the good IL was discussed.     

Nicotinamide Mononucleotide Protects against Retinal Dysfunction in a Murine Model of Carotid Artery Occlusion

Cardiovascular abnormality-mediated retinal ischemia causes severe visual impairment. Retinal ischemia is involved in enormous pathological processes including oxidative stress, reactive gliosis, and retinal functional deficits. Thus, maintaining retinal function by modulating those pathological processes may prevent or protect against vision loss. Over the decades, nicotinamide mononucleotide (NMN), a crucial nicotinamide adenine dinucleotide (NAD⁺) intermediate, has been nominated as a promising therapeutic target in retinal diseases. Nonetheless, a protective effect of NMN has not been examined in cardiovascular diseases-induced retinal ischemia. In our study, we aimed to investigate its promising effect of NMN in the ischemic retina of a murine model of carotid artery occlusion. After surgical unilateral common carotid artery occlusion (UCCAO) in adult male C57BL/6 mice, NMN (500 mg/kg/day) was intraperitoneally injected to mice every day until the end of experiments. Electroretinography and biomolecular assays were utilized to measure ocular functional and further molecular alterations in the retina. We found that UCCAO-induced retinal dysfunction was suppressed, pathological gliosis was reduced, retinal NAD⁺ levels were preserved, and the expression of an antioxidant molecule (nuclear factor erythroid-2-related factor 2; Nrf2) was upregulated by consecutive administration of NMN. Our present outcomes first suggest a promising NMN therapy for the suppression of cardiovascular diseases-mediated retinal ischemic dysfunction.     

Mechanism of action of E7010, an orally active sulfonamide antitumor agent: inhibition of mitosis by binding to the colchicine site of tubulin

E7010 (N-[2-[(4-hydroxyphenyl)amino]-3-pyridinyl]-4-methoxybenzenesulfonami de), an orally active sulfonamide antitumor agent that is currently in a Phase I clinical trial, showed rather consistent growth-inhibitory activities against a panel of 26 human tumor cell lines (IC50 = 0.06-0.8 microg/ml), in contrast to vincristine (VCR; IC50 = 0.0002-0.04 microg/ml), 5-fluorouracil (IC50 = 0.2-30 microg/ml), Adriamycin (IC50 = 0.002-0.7 microg/ml), mitomycin C (IC50 = 0.007-3 microg/ml), 1-beta-D-arabinofuranoxylcytosine (IC50 = 0.005 to >30 microg/ml), camptothecin (IC50 = 0.002-0.4 microg/ml), and cisplatin (IC50 = 0.5-20 microg/ml). It caused a dose-dependent increase in the percentage of mitotic cells in parallel with a decrease in cell proliferation, like VCR. It also showed a dose-dependent inhibition of tubulin polymerization, which correlated well with the cell growth-inhibitory activity. 14C-labeled E7010 bound to purified tubulin, and this binding was inhibited by colchicine but not by VCR. However, its binding properties were different from those of colchicine, as well as those of VCR. E7010 was active against two kinds of VCR-resistant P388 cell lines, one of which showed multidrug resistance due to the overexpression of P-glycoprotein (resistant to Taxol), and the other did not show multidrug resistance (sensitive to Taxol). Furthermore, four E7010-resistant P388 cell lines showed no cross-resistance to VCR, a different pattern of resistance to podophyllotoxin, and collateral sensitivity to Taxol. Therefore, E7010 is a novel tubulin-binding agent that has a wider antitumor spectrum than VCR and has different properties from those of VCR or Taxol.     

Migration, differentiation and integration of an immortalized neural cell line transplanted into the neonatal and adult mouse brain

An immortalized neural cell line V1 was transplanted stereotaxically into the cerebellum and hippocampus of developing and adult mice, and the mode of migration, differentiation and arrangement of the grafted cells were examined by labeling the grafted cells with DiI (1, 1'-dioctadecyl-3, 3, 3', 3'-tetramethylindocarbocyanine perchlorate) and immunohistochemical staining. This cell line was established by transduction of the temperature-sensitive allele tsA58 of SV40 large T antigen oncogene into mouse hypothalamic cells. Grafted cells did not show any tumorigenicity for a long time. Some of the cells grafted into the neonatal cerebellum and hippocampus were arranged along the host cortical layer and showed neuronal or glial differentiation according to the grafted site. The cells grafted into adult cerebellum also showed migration and arrangement along the host cortical layer as well as morphological differentiation into glial cells in a manner similar to that of transplantation to the neonate. On the other hand, the cells grafted into the adult hippocampus made only clusters without forming an organized arrangement. These findings suggest that the grafted cells are integrated into the developmental processes of the host brain, and the mode of differentiation and arrangement of the grafted cells depends on the microenvironment of the different developmental stages of the host brain. The involvement of host blood vessels and astroglial framework in the migration and arrangement of the grafted cells was also suggested. Furthermore, these findings suggest the plasticity of the host brain in response to the grafted cells and the possibility of reconstructing the host brain with this multipotential neural cell line.