Direct-contact type image sensors using a novel amorphous-siliconphotodiode array

A novel type of amorphous-silicon (a-Si:H) photodiode array for direct-contact type (lens-less) line image sensors was developed. A U-shaped top ITO (tin-doped indium oxide) contact and a rectangular a-Si:H window resolves the accumulation of dust from the documents at the steps of the light window. Semi-insulating Al-Si-N and insulating SiN_X stacked films are successfully applied to the surface protection layer to prevent a charge buildup by friction with documents     

Gain of chromosome 20 is a frequent aberration in liver metastasis of colorectal cancers

To investigate the characteristics of the numerical chromosome aberrations in liver metastasis of colorectal cancers, fluorescence in situ hybridization (FISH) for chromosomes 8, 18, 14/22, and 20 was performed in 18 specimens of primary regions and 18 of metastatic regions in liver metastasis of colorectal cancers compared with 15 of non-liver metastatic cancers. Among these numerical aberrations, the gain of chromosome 20, especially copy numbers exceeding three, was frequently observed in primary and metastatic cancers. Among these numerical aberrations, the gain of chromosome 20, especially copy numbers exceeding three, was frequently observed in primary and metastatic regions of liver metastasis groups compared with that of the non-liver metastasis group (P < 0.05). The incidences of gain of chromosome 20 in both regions of the liver metastasis group were higher than that of the non-liver metastasis group (P < 0.05). The gain of chromosome 20 is a frequent aberration in primary and metastatic regions in patients with liver metastatic colorectal cancers and may be available as a genetic marker for the diagnosis or prediction of liver metastasis.     

HAN-based green propellant, application, and its combustion mechanism

Hydroxylammonium nitrate (HAN)-based solutions have been investigated as candidates for a green monopropellant. However, their high burning rate characteristics have hampered the application. In order to elucidate the mechanism of extremely high burning rates of some HAN-based solutions, the combustion characteristics of HAN-based aqueous solutions are studied. It is found that the role of the two-phase region is very important, and intense boiling of water owing to the superheat mechanism is responsible for the high burning rate. Hydrodynamic instability is taken into account, and the dependence of the instability on pressure is estimated. It is found that the instability is strongly affected by the Markstein number. The HAN-based monopropellant is applied to thrusters of a small-sized experimental mockup of a supersonic aircraft and used in the first free-fall test. Their operation is found to be successful and is described in detail.     

Simultaneous Measurement of Thermophysical Properties and Dielectric Properties of PZT-Based Ferroelectric Ceramics by Thermal Radiation Calorimetry

Simultaneous measurements of thermophysical properties and dielectric properties have been performed for PZT-based ferroelectric ceramics. An apparatus based on thermal radiation calorimetry was used in the present measurements. Anomalies in the thermophysical properties were observed near the ferroelectric-to-paraelectric phase transition temperature. The anomalous peak was at almost the same temperature as the inflection point of the dielectric constant. It was found that modification of PZT with increasing Nb, Mg, Zn, and Sr causes a decrease of the Curie temperature and an increase of the hysteresis phenomena for the phase transition, and the values of the thermal conductivity increase with temperature similar to amorphous materials.     

Effect of an amino acid insertion into the omega loop region of a class C beta-lactamase on its substrate specificity

The extended-substrate specificity of Enterobacter cloacae GC1 beta-lactamase is entirely due to a three amino acid insertion after position 207. To clarify the reason for the extended-substrate specificity, Ala, Ala-Ala, Ala-Ala-Ala, and Ala-Ala-Ala-Ala were inserted after position 207 on the basis of the class C beta-lactamase from E. cloacae P99, respectively. The kcat and Km values of all the mutant enzymes for cephalothin, benzylpenicillin and ampicillin were almost the same as those of the wild-type enzyme, except for those of P99-210-4A which were decreased 4-15-fold. On the other hand, the kcat and Km values for oxyimino beta-lactams such as cefuroxime, ceftazidime, and aztreonam increased with increasing numbers of inserted alanines. The kcat values of the mutant enzymes for cefroxime increased 140-7400-fold compared with that of the wild-type. The Km values also increased with almost the same magnitude, resulting in about the same kcat/Km values as that of the wild-type. On progressive inhibition analysis of aztreonam of the mutant enzymes, two kinds of inactive acyl-enzyme with distinct stabilities were observed, and the proportion of the less stable inactive enzyme increased with increasing numbers of inserted alanines. This suggests that the extension of the substrate specificity is due to instability of the acyl-intermediate caused by an increased deacylation rate in the reaction process.     

Heated scallop-shell powder slurry treatment of shredded cabbage

The main component of scallop-shell powder is calcium carbonate (CaCO3). Through heat treatment, CaCO3 in the shell is converted to CaO, which exhibits antibacterial activity. The disinfecting effect of heated scallop-shell powder on shredded cabbage was investigated for various powder concentrations (0.1 to 1.0 g dm(-3)) and treatment temperatures (10 to 40 degrees C). Scallop-shell powder treatment was found to reduce the aerobic bacteria count in cabbage, with increasing effectiveness at higher powder concentrations and treatment temperatures. Coliforms were completely eliminated within 5 min with as little as 0.1 g dm(-3) powder treatment. During storage at 4 degrees C, aerobic bacterial counts did not increase after powder treatment, whereas counts increased with water-washing or sodium hypochlorite treatment at 200 microg dm(-3). The inactivation pattern of bacterial cells in shredded cabbage involved an accelerated decline followed by an extended tail at powder concentrations of 0.1 and 0.5 g dm(-3). We postulate that a fraction of bacterial cells in the initial population becomes tolerant to the shell powder. A proposed model accurately predicts the reducing bacterial counts on shredded cabbage by scallop-shell powder treatment. The decrease in the L-ascorbic acid content of shredded cabbage was approximately 20 to 30% for scallop-shell powder treatment at 0.1 and 0.5 g dm(-3) (20 degrees C), which is almost identical to that by sodium hypochlorite treatment at 200 micorg dm(-3).     

Kinetics of carbide formation from reduced iron in CO-H2-H2S mixtures

Gravimetric measurements were made for the kinetics of the carbide formation from reduced iron by preventing the decomposition of iron carbides and the deposition of carbon by utilizing the effect of sulfur. Particles of a hematite ore were completely reduced in the H₂-H₂S mixture and converted to iron carbide in a CO-H₂-H₂S-CO₂-H₂O-Ar or CO-CO₂-COS-N₂ mixture at 873 to 1073 K. The carbide formation kinetics was drastically accelerated by the addition of a few percent H₂ to CO and reached the maximum at about 20 pct H₂. From morphology observation, it was assumed that the carburization reaction on the surface of pores in the reduced iron determines the carbide formation kinetics, and the carburization rate, df _θ/dt, is expressed at the product of a function of carburization rate, g(p _i, T), and the relative reaction surface area at the time t, 1 − f _θ. Applying the integrated rate equation, -ln (1−f _θ)=g(p _i, T)t, to the experimental results, the value of g(p _i, T) was obtained. By analyzing the carbide formation rate, it was assumed that the elementary reactions determining the carbide formation rate are CO+H(ad) → [C]+OH(ad) and OH(ad)+H₂= H₂O+H(ad), except in the low ratio of , where the rate determining elementary reaction shifts to O(ad)+CO → CO₂. The overall rate Eq. [22] has been proposed for the carbide formation from the reduced iron in CO-H₂-H₂S-CO₂-H₂O mixtures. This article is based on a presentation made in the “Geoffrey Belton Memorial Symposium,” held in January 2000, in Sydney, Australia, under the joint sponsorship of ISS and TMS.