Surface properties and catalytic activities of amorphous niobium phosphate and a comparison with those of H3PO4-treated niobium oxide

Amorphous niobium phosphate was prepared by addition of phosphoric acid to an aqueous solution of potassium niobate. The surface property of the amorphous phosphate was highly dependent on degrees of aging of the precipitate and ranoval of K⁺ contaminant. As well as the phosphoric acid-treated Nb₂O₅) the amorphous phosphate was active as a catalyst for some acid-catalyzed reactions such as MTBE synthesis, esterifications using acetic acid, and alkylations of benzene.     

Epizootic congenital arthrogryposis-hydranencephaly syndrome in cattle: isolation of Akabane virus from affected fetuses

Previous serolgoical studies strongly suggested Akabane virus to be the etiologic agent of epizootic abortion and congenital arthrogryposis-hydranencephaly in cattle, and this view was further corroborated in this study by the isolation of the virus from an aborted fetus in an epizootic of the disease and from a fetus extracted froma cow which was suggested by serologic tests to have a recent infection with the virus. The latter fetus had histological changes of encephalomyelitis and polymyositis, and specific antigens of Akabane virus was shown by the immunofluorescent technique in brain tissues as well as skeletal muscular tissues. The virus was recovered from various fetal tissues and fluids, and in relatively large amounts from brain, spinal cord, cerebral fluid, skeletal muscles and fetal placenta. The intracranial inoculation of suckling mice, 1-2 days of age, was the most sensitive system for Akabane virus isolation and HmLu-1, a continuous cell line from hamster lung, seemed almost as sensitive as suckling mice.     

Structures of three new 24,24-dimethyl-Δ7-sterols fromGynostemma pentaphyllumfromGynostemma pentaphyllum

The structures of three new sterols isolated fromGynostemma pentaphyllum (Cucurbitaceae) have been shown by chemical and spectroscopic methods to be 24,24-dimethyl-5α-cholest-7-en-3β-ol, (22E)-24,24-dimethyl-5α-cholesta-7,22-dien-3β-ol and 24,24-dimethyl-5α-cholesta-7,25-dien-3β-ol.     

A novel point mutation in the mitochondrial tRNA(Ser(UCN)) gene detected in a family with MERRF/MELAS overlap syndrome

We found a new point mutation in the mitochondrial tRNA(Ser(UCN)) gene in a family with MERRF/MELAS overlap syndrome by screening for heteroplasmy by means of chemical cleavage of mismatch (CCM). Our strategy was based on the previous observations that most pathogenic mtDNA mutations in mitochondrial encephalomyopathies are heteroplasmic, whereas almost all neutral mitochondrial polymorphisms are homoplasmic. CCM followed by nucleotide sequencing of the corresponding region of the mitochondrial genome revealed a heteroplasmic mutation at nt 7512 in the tRNA(Ser(UCN)) gene. The 7512 (T to C) mutation disrupts a highly conserved base pair in the acceptor stem, and this mutation was not found in any of 120 normal controls, or in 43 patients with mitochondrial diseases. The proportion of the mutant mtDNA was 93% in muscle, 76 and 87% in the blood of the patients. A family member without apparent neuromuscular symptoms carried less mutant mtDNA. These findings support the view that this mutation is pathogenic in this family. Detection of heteroplasmy by CCM is an efficient means of screening pathogenic mtDNA point mutations.     

Optimum inspection-ordering policies with salvage cost

In this paper we consider an inspection-ordering policy for a single-unit system with two kind of lead times. Introducing the cost structures including salvage cost, we derive the cost effectiveness defined by (The steady-state availability)/(The expected cost per unit time in the steady-state). We show that under certain conditions there exists a finite and unique optimum policy maximizing that cost effectiveness. We also present the numerical examples for illustration.     

Changes in nuclear DNA and RNA during epidermal keratinization

The distribution of nucleic acids within nuclei of epidermal cells in skin from guinea-pig ear was investigated using an indirect enzyme digestion technique to observe both DNA and RNA, and a direct Schiff-Thallium reaction technique, to observe DNA alone. Similar results were obtained by both methods. The distribution of DNA and RNA change gradually in nuclei as epidermal cells differentiate. DNA in cells of the lower strata is localized in essentially the same areas in which electron-opaque components are seen by conventional electron microscopy. With the cytochemical treatments, however, we found that DNA is not present in all electron-opaque areas of nuclei in superficial granular cells. RNA is present in the nucleoli of cells in all layers, but its density is also lower in the upper granular cells. We postulate that nucleic acids in nuclei of granular cells gradually decrease and that the space is filled with newly synthesized electron-dense protein, as part of the differentiation process.     

Pseudo-dynamic buckling experiments on thin cylindrical shells under biaxial seismic loads

A buckling design research program has been carried out to establish seismic design guidelines for a fast breeder reactor. In doing so, the buckling strength of the cylindrical part of the reactor vessel of a fast breeder reactor under horizontal and vertical seismic loads has been clarified. The effects of axial loads on the horizontal seismic responses in pre- and post-buckling states of thin cylindrical shells are investigated. Pseudo-dynamic buckling experiments are performed to study the dynamic buckling characteristics of thin cylindrical structures when subjected to seismic loads. The buckling tests use model cylinders made of an aluminum plate and a biaxial loading test apparatus. The axial seismic loads reduce the lateral load-carrying capacity of the shells in the pre- and post-buckling regions so that they amplify the horizontal response displacement. An amplification factor that accounts for the effects of the vertical loads is presented and its validity is verified experimentally.     

Thermal conductivity and cycle characteristic of metal hydride sheet formed using aramid pulp and carbon fiber

This paper describes the thermal and hydrogenation properties of a metal hydride (MH) sheet consisting of MH powder, aramid pulp, and carbon fiber. MH sheets were prepared by the wet paper method in which an agglutinated slurry of raw materials was dispersed onto a stainless steel mesh in water and then the sheet was dehydrated and dried. The cyclic characteristics and thermal conductivities of the MH sheets were experimentally investigated. The effects of changing the carbon fiber ratio and the measurement direction on the effective thermal conductivity were measured by the steady heat flow method. The thermal conductivity increased to 3.20 W/m·K with increasing carbon fiber ratio only in the planar direction. The decreases in mass due to removing MH powder and/or carbon fiber from sheet were less than 1 mass% after around 100 hydrogen absorption/desorption cycles. Moreover, the MH sheet was effective at decreasing the stress on the reactor vessel due to the expansion of MH during hydrogen absorption/desorption.