Purification and characterization of a lectin from Wistaria floribunda seeds

A lectin from Wistaria floribunda seeds which specifically binds to N-acetyl-D-galactosamine was purified to homogeneity as judged by polyacrylamide gel electrophoresis. Its molecular weight was estimated to be 68,000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. It dissociated into subunits on reduction with 2-mercaptoethanol with concomitant loss of hemagglutinating activity. On oxidation in air, the subunits reassociated into the lectin molecules with hemagglutinating activity. Carboxymethylation of the subunits with iodoacetic acid prevented their reassociation on oxidation in air. The molecular weight of the subunits was 32,000, which is about one-half that of the native lectin, suggesting that the lectin consists of two subunits. The results total, NH2-terminal, and COOH-terminal amino acid analyses, and mapping of the tryptic digest of the lectin indicated that these two subunits were indistinguishable and were probably identical, and that they were linked together covalently through a single disulfide bond. Equilibrium dialysis experiments show that the lectin and its subunit molecules are divalent and monovalent, respectively, with respect to sugar binding. The lectin is a glycoprotein, containing 3.2% carbohydrate. The carbohydrate moiety is composed of mannose, galactose, and glucosamine is a molar ratio of 1:2:1 and these sugars seem to be linked as a single oligosaccharide chain to each subunit of the protein.     

Patterning of Tin Oxide Film from Photoreactive Precursor Solutions Prepared via the Addition of N-Phenyldiethanolamine

Metallo-organic compounds were synthesized for the preparation of tin oxide fine patterning via the addition of alkanolamines. Tin(IV) isopropoxide was chemically modified with diethanolamine (DEA) and/or N -phenyl-diethanolamine (PhDEA). Then, the chemical stability and photoreactivity of the prepared metallo-organic compounds were compared. A tin precursor solution that was formed via the stepwise additions of both DEA and PhDEA showed good chemical stability in air and efficient photoreactivities under ultraviolet irradiation. The fine patterning of tin oxide was achieved successfully on a substrate, using the precursor solution.     

Maximum potential of PV installation based on an energy system planning model considering a distribution voltage constraint

As the key solution for energy sustainability this decade, the growth of installing photovoltaic (PV) systems has dramatically increased. However, the high penetration of PV systems can cause a voltage variation problem in a distribution grid. This paper proposes a model for evaluating the maximum potential for installing PV systems in an urban area under a bus voltage constraint. A PV system is considered as an energy system alternative that replaces a conventional system. Regarding the power variation, it is necessary to add a parameter that is used to evaluate the variation of PV systems in terms of a standard deviation to the PV systems' electric load curve. The installations of PV and conventional systems are determined as share solutions for each load area along a distribution network. Total power loads and variations in each load area are input to a load flow calculation to obtain each bus voltage and confirm the voltage constraint. Finally, the total PV system installations over the whole network area is maximized. The alternative PV system with battery installation is introduced to validate the model evaluation when comparing with a typical PV system without a battery, which has larger power variation. Furthermore, adjusting the sending voltage at a substation to increase the PV installation is validated using the proposed model. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

An analysis of lymphocyte subsets in the regional lymph nodes of patients with papillary thyroid carcinoma

Lymphocyte subsets in the lymph nodes regional to papillary thyroid carcinoma were determined using flow cytometry to ascertain the differences in local immunological responses between elderly and young patients. Lymph nodes from age-matched patients with benign thyroid tumors were used as controls. No significant alterations in lymphocyte subsets were observed in the lymph nodes from the young patients regardless of whether metastasis was present, whereas those from the elderly patients showed significant decreases in pan T cell (CD2+, CD3+) and cytotoxic T cell (CD8+, CD8+CD11b-) populations, and a significant increase in B cells (CD19+) compared with those from both the young patients and the age-matched controls. These results indicate that local immunological alterations occur in elderly patients with papillary thyroid carcinoma, and we believe that immunological changes are one of the clinical characteristics of this tumor.     

Optical and electrical properties of boron nitride oxide films

Polycrystalline boron nitride oxide (BNO) films are synthesized by RF magnetron sputtering. It is found that the bandgap of the BNO film increases with increasing oxygen composition. The bandgap energy as wide as 5.5 eV is obtained with oxygen composition of 17%. The electrical resistivity is estimated to be as high as 10¹³ Ωcm. Metal/BNO/metal structures are fabricated with various metals such as Ni, Cu and Al, and electrical characterization are performed for metal/BNO contacts. The true Schottky barrier heights are estimated for metal/BNO contacts. The true Schottky barrier height decreases with increasing metal work function. This behavior of the Schottky barrier height suggests that the BNO film has p-type electrical conduction.     

Characterization of BCN film after wet process for interconnection integration

In this study, we investigate the influence of the wet chemical processes involved in the chemical treatment of boron carbon nitride (BCN) films deposited by plasma-assisted chemical vapor deposition (PACVD). BCN film is expected to be a low dielectric constant (low-K) material useful in fabricating future generation LSI devices. BCN film with less than 10% oxygen was hardly etched. The etching rate of the BCN film with an oxygen composition ratio more than 10% depends on the pH of the solution. The relationship between the film etching rate and the atomic bonds in BCN film is also investigated using XPS and FTIR. It was found that the BCN films without C–O and B–O bonds are not etched by acid and alkaline solutions. Therefore, suppression of oxygen concentration in the BCN film is important for LSI integration.     

Influence of atomic bonds on electrical property of boron carbon nitride films synthesized by remote plasma-assisted chemical vapor deposition

Boron carbon nitride (BCN) films are synthesized with various growth conditions by remote plasma-assisted chemical vapor deposition method. The chemical bonding in the BCN film is modified by the growth condition. Optical and electrical properties are investigated for BCN films with various chemical bonding. Electrical characterization is carried out for the BCN films which have the same bandgap energy and different C composition ratio and have the same C composition ratio and different bandgap energy.     

Barrier height enhancement of InP Schottky junctions by treatment with photo-decomposed PH/sub 3/

Au-InP Schottky junctions are formed on a surface treated by ArF excimer laser photolytic process of phosphine (PH/sub 3/) gas. The Schottky junction has a metal-insulator-semiconductor (MIS) structure because of the existence of a thin P layer deposited on the InP surface. The barrier height increases to 0.65 eV and the reverse current is reduced by more than two orders of magnitude compared with the case of Schottky junctions without photolytic treatment. The Richardson constant of the novel Schottky junction is evaluated as 0.126 A cm/sup -2/ K/sup -2/ from the temperature dependence of the saturation current.<>