Template-free hydrothermal synthesis of hollow hematite microspheres

Hollow hematite (α-Fe₂O₃) microspheres with an average diameter of 3-4 μm and a shell thickness of approximate 150 nm was synthesized by a simple hydrothermal route using FeCl₃·6H₂O solution and acetic acid without using any templates. The hollow microspheres were composed of α-Fe₂O₃ nanoparticles with the diameter range from 20 to 40 nm. The effects of reaction parameters such as reaction time, temperature, concentration of FeCl₃·6H₂O solution, and initial pH on the morphology of the final products were investigated. A possible formation mechanism of hollow α-Fe₂O₃ microspheres was also proposed, where the acetic acid played a role of etching in the formation of hollow structure.     

Involvement of cytochrome P450 in hydroxylation of propylbenzene by Fusarium moniliforme strain MS31

Fusarium moniliforme strain MS31 can oxidize propylbenzene to (R)-1-phenylpropanol with what may be a cytochrome P450. Hydroxylation of propylbenzene needed molecular oxygen, and NADPH as a coenzyme gave a higher yield than NADH. The hydroxylation proceeded further when FAD and FMN were added than in their absence, suggesting that the enzyme was a flavo-protein. Carbon monoxide inhibited the hydroxylation, as did other cytochrome P450 inhibitors such as SKF 525A and miconazole. These characteristics matched those of a microsomal cytochrome P450 monooxygenase system that contained NADPH-cytochrome P450 reductase.     

Updated data dissemination methods for updating old replicas in ad hoc networks

In this paper, we propose two updated data dissemination methods to not only reduce the number of accesses to old replicas, but also to improve the data accessibility in ad hoc networks where data items are updated regularly. In the first method, when a mobile host updates a data item, it disseminates the updated data item after the flooding of with invalidation reports. In the second method, two newly connected mobile hosts disseminate updated data items with each other after the flooding with invalidation reports.     

Properties of graphite prepared from boron-doped pitch as an anode for a rechargeable Li ion battery

Boron-doped graphites were derived from a naphthalene-based pitch mixed with para-xylene glycol (PXG) or dimethyl para-xylene glycol (DMPXG) as a cross-linking agent and three types of boron-containing compounds as a graphitization catalyst, and their anode performances were investigated. The structural analysis of the obtained graphites revealed that PXG functioned mainly as a two-dimensional cross-linking agent during the heat treatment process and DMPXG functioned partially as a three-dimensional. The average interlayer spacing decreased and lattice constant, a₀, and graphitizability increased with increasing the amount of boron atoms added. The result indicated that the carbon atoms were replaced by boron atoms. The anode performance was improved by the enhancement of graphitizability. The structural parameters and anode performance of boron-doped graphites did not depend on the kind of boron-containing compounds but the amount of boron atoms added in pitch and the kind of cross-linking agent.     

Mutation analysis of the WT1 gene in myelodysplastic syndromes

Infectious mononucleosis due to Epstein-Barr virus (EBV) is almost always a self-limited disease, most commonly seen in young adults. Hepatitis is a well-recognized complication of EBV infection that usually resolves spontaneously. Jaundice occasionally results from the unusual complication of autoimmune haemolytic anaemia rather than hepatitis. We report a 60-year-old man with severe cholestatic jaundice whose history, liver histology and laboratory findings suggested EBV infection. He also developed significant jaundice related to his hepatitis, but not to autoimmune haemolysis, a situation that led to diagnostic delay. Costly diagnostic laboratory tests and invasive procedures were performed to rule out a malignant extrahepatic biliary obstruction. Physicians need to be aware of this complication and EBV infection should be included in the differential diagnosis of cholestatic jaundice in the elderly.     

Reinitiation of spermatogonial mitotic differentiation in inactive old BDF1 mouse seminiferous tubules transplanted to W/Wv mouse testis

The seminiferous epithelia of old mice (33 mo of age) are composed of spermatogonia and Sertoli cells. Histochemical examination using the anti-c-kit monoclonal antibody demonstrated that the number of differentiating type A spermatogonia decreases with age. To elucidate the differential activity of old mouse spermatogonia, we transplanted extremely thin seminiferous epithelia of old BDF, mice into W/Wv mouse testes and examined whether or not they could reinitiate differentiation. Artificially cryptorchid mice were used as the control. At 2 wk after transplantation, spermatocytes and round spermatids were detected in transplanted seminiferous tubules of the control, whereas the most advanced spermatogenic cells in those of old mice were spermatocytes. At 4 wk after transplantation, although elongated spermatids were detected in transplanted tubules of the control, haploid cells (spermatids) were still undetectable in those derived from old mice. Thus, meiosis was never restored, although spermatogonia of old mice can reinitiate differentiation into spermatocytes under suitable testicular conditions. Since it has been reported in several mammalian species that age-related changes in the testicular microenvironment lead to the gerontal cessation of spermatogenesis, the present results suggest that both a defective extratubular environment and a defective intratubular environment may cause the cessation of spermatogenesis in old BDF, mice.     

Contribution of HLA genes to genetic predisposition in diffuse panbronchiolitis

Diffuse panbronchiolitis (DPB) in East Asia is a distinctive chronic obstructive pulmonary disease of unknown etiology. We hypothesize that the disease susceptibility is due to genetic predisposition unique to Asians. Association between human leukocyte antigen (HLA)-Bw54 and the disease was previously reported. In the present study, using newly developed polymerase chain reaction (PCR)- based methods, we directly analyzed HLA class I and II alleles in 76 Japanese patients. HLA-A, -B, and -C antigens were screened by the conventional typing method, and then B22-group alleles including HLA-B54 were genotyped by single-strand conformation polymorphism analysis. Alleles of HLA-DRB1 gene were fully determined by the microtiter plate hybridization method. Thirty-seven percent of the patients possessed HLA-B*5401 allele conserved predominantly in East Asians, as compared with 15% of 110 healthy volunteers (chi2 = 12.4, p = 0.0004). In addition, 4% of the patients possessed B*5504 also unique to Asians but a rare allele which was not found in normal control subjects in this study. Typing of HLA-DRB1 class II gene did not demonstrate strong positive association with the disease. A33, B44, and DRB1*1302 showed negative association with the disease. We conclude that distinctive molecular structure of HLA-B alleles or a closely linked gene in the HLA region contributes to genetic predisposition in diffuse panbronchiolitis. This may partly explain why this disorder is found primarily in Asians.     

Efficient synthesis of nonnatural mutants in Escherichia coli S30 in vitro protein synthesizing system

Factors that affect the efficiency of in vitro synthesis of mutant proteins that contain nonnatural amino acids were investigated. The process of the nonnatural mutagenesis consists of chemical aminoacylation of a tRNA that contains a 4-base anticodon, followed by in vitro synthesis in the presence of an mRNA that contains the corresponding 4-base codon. Detailed studies on the time courses of the synthesis revealed two major factors that suppress the yield of nonnatural mutants compared with the wild-type protein. First, a cyclic tRNA that exists as a by-product of the chemical aminoacylation inhibits the protein synthesis. Second, the very short lifetime of a tRNA aminoacylated with a nonnatural amino acid limits the protein yield. As a simple and practical way of surmounting these factors, aminoacyl tRNA was added into the in vitro system at 5 min after the start of the synthesis. The addition increased the protein yield up to the level of conventional proteins in the in vitro system.     

红外相机CASCAM的电动系统设计

介绍了红外相机CASCAM的电动系统设计。系统采用AT90S8515单片机和TA8435集成芯片组成驱动电路的核心,通过电机选择电路和位置反馈电路实现对步进电机的选择驱动和定位、复位。系统采用MAXIM232芯片实现单片机和上位机之间的串行通讯。系统软件以汇编语言编制,并给出了系统程序框图。经实验验证,该系统运行可靠,达到了设计要求。