Dehydrogenation process in orthorhombic hydrogen molybdenum bronze under vacuum heating

Dehydrogenation of orthorhombic hydrogen molybdenum bronze, H_0.30MoO₃, under vacuum heating was investigated using various techniques. The dehydrogenation occurrs in the form of the H₂O evolution from H_0.30MoO₃. The H₂O evolution with a rise in temperature proceeds in three steps: The first stage, up to ～287°C, is the formation of H_0.21MoO_2.95, corresponding to orthorhombic bronze with the lowest hydrogen content, and the second stage, ～287 to ～395°C, leads the formation of H_0.06MoO_2.88 isomorphous with MoO₃. The final stage finishes at ～446°C and yields MoO_2.86. The MoO_2.86 is a non-stoichiometric compound with the MoO₃ structure and transforms at ～610°C to a mixture of Mo₄O₁₁ and MoO₃, the equilibrium phase for the MoO_2.86 composition at 610°C.     

Polymerization of 1,3‐dienes containing functional groups: 8. Free‐radical polymerization of 2‐triethoxysilyl‐ 1,3‐butadiene

The presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene ( 1 ) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ( ) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (R_p) was found to be R_p = k[AIBN]^0.5[ 1 ]^1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol^?1. The monomer reactivity ratios in copolymerization with styrene were r ₁ = 2.65 and r_st = 0.26. The glass transition temperature of the polymer of 1 was found to be ?78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry     

Improvement of neutron startup source handling work by developing new transportation container for high-temperature engineering test reactor (HTTR)

The high-temperature engineering test reactor (HTTR) has three neutron startup sources (NSs) in the reactor core, each of which consists of ²⁵²Cf with 3.7 GBq, installed in NS holder and subsequently in a control rod guide block (CR block). The NSs are exchanged at the interval of approximately seven years. The NS holders are transported from the dealer's hot cell to the HTTR using a transportation container. The loading work of NS holders to the CR blocks is subsequently carried out in the fuel handling machine maintenance pit of HTTR.

Technical issues, which are the reduction and prevention of radiation exposure of workers and the exclusion of falling of NS holder, were extracted from the experiences in the past two exchange works of NSs to develop a safety handling procedure. Then, a new transportation container special to the NSs of HTTR was developed to solve the technical issues while keeping the cost as low as that for overhaul of conventional container.

As a result, the NS handling work using the new transportation container was safely accomplished by developing the new transportation container which can reduce the risks of radiation exposure dose of workers and exclude the falling of NS holder.     

A 60-ns 16-Mbit CMOS DRAM with a transposed data-line structure

Low-noise, high-speed circuit techniques for high-density DRAMs (dynamic random-access memories), as well as their application to a single 5-V 16-Mb CMOS DRAM with a 3.3-V internal operating voltage for a memory array, are described. It was found that data-line interference noise becomes unacceptably high (more than 25% of the signal) and causes a serious problem in 16-Mb DRAM memory arrays. A transposed data-line structure is proposed to eliminate the noise. Noise suppression below 5% is confirmed using this transposed data-line structure. A current sense amplifier is also proposed to maintain the data-transmission speed in common I/O lines, in spite of a reduced operating voltage and increased parasitic capacitance loading in the memory array. A speed improvement of 10 ns is achieved. Using these circuit techniques, a 16-Mb CMOS DRAM with a typical RAS access time of 60 ns was realized     

Regulation of Polyunsaturated Fatty Acid Biosynthesis by Seaweed Fucoxanthin and Its Metabolite in Cultured Hepatocytes

The effects of a seaweed carotenoid, fucoxanthin, and its physiological metabolite, fucoxanthinol, on the biosynthesis of polyunsaturated fatty acids (PUFA) were investigated using cultured rat hepatoma BRL‐3A. The metabolism of α‐linolenic acid (18:3n‐3) was suppressed by the addition of these carotenoids, resulting in a decrease in the content of eicosapentaenoic acid (20:5n‐3), which suggested a down‐regulation of metabolic enzymes such as fatty acid desaturase and elongase. An increase in the content of docosahexaenoic acid (22:6n‐3), as observed in previous studies in vivo, might be a buffering action to maintain the membrane fluidity. The suppressive effect of fucoxanthinol on ?6 fatty acid desaturase was not at the level of gene expression but due to specific modifications of the protein via a ubiquitin–proteasome system. A proteomic analysis revealed several factors such as phosphatidylethanolamine‐binding protein that might be involved in the observed action of fucoxanthin. These findings will contribute to studies on the elucidation of the precise molecular mechanisms underlying the regulation of PUFA biosynthesis by fucoxanthin.     

Determination of back-pressure profile for forward extrusion using sequential approximate optimization

This paper proposes a method for determining optimal back-pressure profile in forging of aluminum alloy using a sequential approximate optimization (SAO). In forging, it is important to improve the mold filling for the product quality. In addition, it is preferable to produce a product with a minimum forming energy. To achieve these objectives simultaneously, a forging method with back-pressure profile is proposed. Here, the back-pressure profile implies that the back-pressure varies through the stroke. In this paper, a multi-objective optimization (MOO) problem is formulated. To improve the mold filling, an unfilled area is taken as the first objective function. Furthermore, a forming energy during the forging is taken as the second objective function. Numerical simulation in the forging is so expensive that the SAO using the radial basis function (RBF) network is adopted, and the pareto-frontier is identified with a small number of simulation runs. Based on the numerical result, the experiments are also conducted. It can be found from these results that, the back-pressure profile approach is valid for improving the mold filling as well as the forming energy.     

Oesophageal cancer coexisting with colorectal lesions

OBJECTIVE: To investigate the incidence of colorectal lesions in patients who present with oesophageal cancer. DESIGN: Prospective open study. SETTING: University hospital, Japan. SUBJECTS: 135 of 218 patients who presented with squamous cell carcinoma of the oesophagus during the seven year period 1988-1994 were randomly allocated to have a barium enema examination. INTERVENTIONS: Barium enema examinations, and if colorectal lesions were found, colonoscopy and biopsy. MAIN OUTCOME MEASURE: Incidence of coexistent colorectal lesions. RESULTS: No abnormal findings were found in 52 (39%), diverticula were present on 37 (27%), benign polypoid lesions in 51 (38%), and malignant lesions in 6 (4%). We examined the clinical and histopathological details of all patients to see if it was possible to distinguish the patients at high risk of developing oesophageal and colorectal cancer but could find no differences among the groups. CONCLUSION: Asymptomatic colorectal lesions are relatively common in patients with squamous cell carcinoma of the oesophagus in Japan.     

Characterization of adenosine deaminase (ADA)-negative B-lymphoblastoid cells cocultured with ADA-positive fibroblasts

A cell line, BAD05, derived from B lymphocytes of an adenosine deaminase (ADA; EC 3,5,4,4)-deficient patient could not proliferate in a serum-free medium containing 100 mumol/l deoxyadenosine. When BAD05 was cultured with ADA-positive fibroblasts, the proliferation of BAD05 was improved. BAD05 cell density increased when the initially mixed ratio of fibroblasts/BAD05 was 1/10 or higher, but decreased when the ratio was 1/20 or lower. Deoxyadenosine concentrations in the medium and ATP and deoxyATP (dATP) levels in the BAD05 were measured after 4 hours of coculture at initial BAD05 cell densities of 1 x 10(5) and 1 x 10(6) cells/ml. Deoxyadenosine concentrations in the medium decreased as the density of fibroblasts increased. The dATP level decreased as the mixed ratio rose. The ratio of fibroblasts/BAD05 rather than the cell density of fibroblasts had a larger effect on the dATP levels in BAD05. Under our experimental conditions, ADA-negative cells proliferated well when the ratio of ADA-positive cells/ADA-negative cells was over 1/10.     

Gastrointestinal submucosal tumors: evaluation with endoscopic US

PURPOSE: To describe the endoscopic ultrasound (US) features of benign versus malignant submucosal tumors throughout the gastrointestinal tract. MATERIALS AND METHODS: One hundred nine patients aged 24-81 years suspected to have submucosal tumors (11 esophageal, 41 stomach, 24 duodenal, and 33 colorectal tumors) at barium studies or endoscopy underwent endoscopic US. The layer of origin, internal echo pattern, and lesion margin were analyzed by means of consensus and independent interpretation by three radiologists. RESULTS: Endoscopic US findings revealed several distinct patterns among various submucosal tumors. Sixteen (94%) of the 17 homogeneous lesions with histopathologic findings of malignancy were hypoechoic, although 29 (43%) of the 68 homogeneous lesions with histopathologic findings of benignity were similarly hypoechoic. Homogeneous lesions that were anechoic, of intermediate echogenicity, or hyperechoic were almost exclusively benign (39 [98%] of 40). In contrast, 23 (96%) of the 24 malignant lesions were heterogeneous (n = 7) or homogeneously hypoechoic (n = 16). The sizes of benign and malignant lesions were significantly different (P < .05). There was no significant difference in the echo pattern (i.e., homogeneous versus heterogeneous), but there was a significant difference in the proportion of hypoechoic versus nonhypoechoic lesions (anechoic, hyperechoic, or of intermediate echogenicity; P < .001). CONCLUSION: The differential diagnosis of gastrointestinal submucosal tumors is assisted with endoscopic US.     

Hemifacial dismasking flap for anterior skull base tumor--technical note

A new approach to malignant tumor in the anterior skull base using a hemifacial dismasking flap is described. A bicoronal incision is extended unilaterally down to the neck, degloving the craniofacial tissue to widely expose the skeleton underneath, allowing easy resection of an extensive tumor without postoperative scarring of the face. This method has been used successfully on five patients.