Determining factors for anodic polarization curves of typical structural materials of boiling water reactors in high temperature – high purity water

In order to examine the anodic polarization characteristics of typical structural materials of boiling water reactors (BWRs), the anodic polarization curves of type 316L stainless steel (316L SS) and Alloy 182 were measured in deaerated high purity water at 553 K using the previously reported measurement method which was confirmed suitable for high temperature – high purity water. In order to specify which constituent element determines the dissolution characteristics of these materials, the anodic polarization curves of pure iron, pure nickel, and pure chromium were also surveyed. The anodic polarization curve of 316L SS was determined to have active, passive, and transpassive states which were the same as type 304 SS (304 SS) showed. But, Alloy 182 had different polarization characteristics especially near the corrosion potential as it had no active state. From comparison results of the polarization characteristics of these materials and their constituent elements, the corrosion characteristics of these materials were concluded to be mainly determined by the corrosion characteristics of chromium.     

Formation of W/O microemulsion based on natural glycolipid biosurfactant, mannosylerythritol lipid-a

Mannosylerythritol lipid-A (MEL-A) is a glycolipid biosurfactant abundantly produced from soybean oil by microorganisms at a yield of up to 100 g/L. In this study, the formation of water-in-oil (W/O) microemulsion based on the single component of MEL-A was confirmed using dynamic light scattering (DLS) and freeze fracture electron microscopy (FF-EM). DLS and FF-EM measurements revealed that the diameter of the microemulsion increases with an increase in water-to-surfactant mole ratio (W(0)) ranging from 20 to 60 nm, and the maximum W(0) value was found to be 20, which is as high as that of soybean lecithin. Glycolipid biosurfactant has a great potential for the formation of W/O microemulsion without using any cosurfactants.     

Effects of flow rate on sensitivity and affinity in flow injection biosensor systems studied by 55-MHz wireless quartz crystal microbalance

In this paper, we developed a 55-MHz wireless-electrodeless quartz crystal microbalance (QCM) and systematically studied the effects of flow rate on the sensitivity to the detection of proteins and on the affinity between biomolecules evaluated by the flow injection system. Brownian motion of proteins in liquid suggests a low probability of meeting, and the convection effect plays an important role in the sensitivity and the affinity in the flow cell injection system. The wireless quartz crystal was isolated in the QCM cell, and flow rates between 50 and 1000 microL/min were used for monitoring binding reactions between human immunoglobulin G and Staphylococcus aureus protein A. The sensitivity was significantly increased as the flow rate increased, while the affinity value remained unchanged. However, the affinity value was affected by the reaction time for a large-concentration analyte, indicating the need of a high-sensitivity biosensor system for accurate evaluation of affinity. The electrode effect on the QCM sensitivity was also theoretically investigated, showing that the electrode significantly deteriorates the QCM sensitivity and makes the Sauerbrey equation invalid.     

Patterning cultured cells by visible light illumination with photosensitizers

We showed that PC12 cells and 3T3 cells cultured in dishes were killed by illumination with visible white light from a halogen lamp at 7 x 10(4) lx for 5 min in the presence of either 10 microM hematoporphyrin or 2 microM methylene blue as a photosensitizer. This simple technique, based on the photodynamic reaction via generation of reactive oxygen species can be applicable for patterning cultured cells.     

CHARACTERISTICS OF WATER UPTAKE OF AUSTRALIAN POLISHED BARLEY IN SHOCHU-MAKING

Characteristics of water uptake during steeping of 70% polished Australian barley, used as material for shochu making, were studied on 6 grain samples. There were some similarities in water uptake curves in spite of the differences in varieties and regions of harvest. Polished barley abruptly absorbed water at the same time when in contact with water. After 5 h the water uptake content reached 52 to 56, 54 to 59, and 58 to 63% grain wet weight at 15, 20, and 30°C respectively. The relationship between water uptake and steeping time may be described by the equation Y=aX^b, where Y is the water uptake (%), X is the time (min), and a and b are coefficients¹. From the data obtained with Schooner (South), the water uptake curve in steeping at 15°C was described as Y=5.50X^0.40 (r²=0.993). Furthermore a log-log plot of water uptake (%) against integrated steeping temperature (1ST), which was presented by the product of temperature and time, showed a very clear linear relationship, and could be represented by Y=2.047(T · t)^0.382 (r²=0.987). The coefficient values a and b determined the relationship of water uptake and 1ST on 6 samples. The values of 5 samples, excluding Stirling (West) were close (a=2.05 to 2.33 and b= 0.37 to 0.38), and no differences were apparent amongst these varieties and regions. Stirling (West) with a=1.81 and b=0.40 were similar to the Japanese barley cultivar Nishinochikara (a=1.99, b=0.39). The Schooner (South) equation could generally be applied to control water uptake during steeping on 70% polished Australian barley supplied to our factory. The water uptake values from the steeping experiments were between 35.1 and 36.7% when the objective value was set at 35% .     

Preparation and properties of nanosized biodegradable polymer capsules

This article reports the preparation and properties of nanosized biodegradable polymer capsules synthesized using the electrocapillary emulsification method. The biodegradable polymers used were poly(ε-caprolactone) (PCL), which is a highly biodegradable and biocompatible polymer, and poly(lactide-co-glycolic acid) (PLGA). While the size of the capsules prepared using PCL alone was in the micrometer range, it decreased with an increase in the amount of PLGA added to PCL and eventually reached the nanometer level. When the electrocapillary emulsification applied potential was 2000 V, the sizes of the capsules (PCL:PLGA = 5:5) ranged from 50 to 80 nm. The percentage of glucose trapped in the PCL/PLGA nanocapsules was higher than 80% and the duration of glucose release from the nanocapsules was about two times longer than that from PCL capsules.     

Gallium Trichloride‐Catalyzed Exhaustive α‐Ethynylation Reaction of 1‐Silylacetylenes

Gallium trichloride (GaCl₃) catalyzes the ethynylation reaction of a 1,4‐enyne with chlorosilylacetylene at the propargyl position giving a triethynylvinylmethane. This catalytic method can be applied to the exhaustive α‐ethynylation of 1‐silylacetylenes possessing less acidic propargyl protons, and mono‐, di‐, and triethynylated products are obtained depending on the structure of the starting materials.     

Engineering surface and development of a new DNA micro array chip

This paper proposes a new concept of the ‘engineering surface’, which extends the conventional idea of a functional surface by combining it with micro/nano manufacturing technology. Characteristic features and possibilities of the engineering surface are discussed in detail. This paper reviews studies on micro/nano fabrication technologies for advanced materials and evaluation technology for surface function. New fabrication technologies, micro machining and nano forming, are introduced, which will be basic manufacturing processes of the engineering surface. Also, a new surface evaluation technique is introduced for the surface energy of the nano fabricated surface. Design of a new DNA micro array chip is introduced as an example of applications of the engineering surface. Controllability of surface property by nano fabrication is studied.     

Spontaneous hydrolytic degradability of copolyesters having tetrahydropyran rings in their backbones

Homo- and copolyesters, containing 2,5-linked tetrahydropyran rings in their backbones, were prepared by cationic ring-opening polymerization of bicyclic lactones, 2,6-dioxabicyclo [2.2.2] octan-3-one ( 1 ), and its 4-methoxy-carbonyl and 4-methoxy-carbonyl and 4-benzyloxycarbonyl derivatives ( 3 and 4 ). Copolyesters, having pendant carboxyl groups, were derived from the copolymers containing 4 as one of the comonomers by the catalytic hydrogenolysis of the pendant benzyloxy–carbonyl groups. Copolyesters, containing both 2,5-linked and 2,6-linked tetrahydropyran rings in the main chains, were obtained by the copolymerization of 1 with 6,8-dioxabicyclo [3.2.1] octan-7-one ( 13 ), which is a structural isomer of 1 . Spontaneous hydrolytic degradability of these polyesters was investigated in a phosphate buffer solution (pH 7.5) at 27°C. The degradability of the polyesters markedly depended on the molecular structure: hydrophobic pendant groups retarded the hydrolytic degradation, whereas hydrophilic pendant groups accelerated it. In particular, a small amount of pendant carboxyl groups significantly enhanced the hydrolytic degradability of the copolyesters from 1 . Polyesters, containing 2,6-linked tetrahydropyran rings in their backbones, underwent hydrolytic degradation more readily than those entirely consisting of 2,5-linked tetrahydropyran rings. © 1994 John Wiley & Sons, Inc.     

Facilitated permeation of myoglobin through porous membranes: Different permeation behavior through membranes of polyoxyethylene- and dextran-conjugated polyamides prepared by quasi-living polymerization of a bicyclic lactam

In the ultrafiltration test of a myoglobin solution through porous membranes of the ABA-type block copolymers composed of polyamide as outer segments and polyoxyethylene (M_n = 1.9–2.0 × 10⁴) as an inner segment, in which the values of weight fraction of the polyamide segments (W) were 0.90, 0.84, 0.82, 0.81, and 0.73, the concentration of the permeate was found to be much higher than that in feed under the pressure difference of 1–2 kg/cm². Such singularly facilitated permeation was observed also in the test through the dense membranes of the polyamide–polyoxyethylene block copolymer with W of 0.81 and 0.73. On the other hand, neither porous nor dense membranes of the graft copolymer (W = 0.83) having a dextran stock (M_n = 1.8 × 10⁴) and 2.6 pieces of polyamide branches showed similar facilitated permeation, although dextran was soluble in water as well as polyoxyethylene. The apparent interaction of myoglobin with dextran may be stronger than that with polyoxyethylene. © 1994 John Wiley & Sons, Inc.