Isolation of antimicrobial agent from the marine algae Cystoseira hakodatensis

Cystoseira hakodatensis is an unutilised brown algae belonging to family Sargassaceae. A crude methanol extract from the algae showed inhibitory effects on the growths of Bacillus cereus and Bacillus licheniformis. To isolate the major antimicrobial agent, a sequential active‐guided isolation procedure was applied: liquid–liquid extraction, column chromatography and bio‐autography. A marked antimicrobial agent (active α) was isolated in hydrophobic fraction and was determined to phenolics without carbohydrates and proteins by phytochemical test. Regarding the antimicrobial potential, the isolated active α showed better inhibitory effects against B. cereus and B. licheniformis at 2 and 4 times of lower concentrations (62.5 and 31.3 μg mL^?1) in comparison with epigallocatechin gallate. These results showed that C. hakodatensis is a potential source of antimicrobial agent capable of preventing the growth of the two bacteria.     

Distribution of carbon contamination in MgAl2O4 spinel occurring during spark-plasma-sintering (SPS) processing: I – Effect of heating rate and post-annealing

Carbon contamination from the carbon paper/dies during spark-plasma-sintering (SPS) processing was examined in the MgAl₂O₄ spinel. The carbon contamination sensitively changes with the heating rate during the SPS processing. At the high heating rate of 100 °C/min, the carbon contamination having organized structures occurred over almost the entire area from the surface to deep inside the SPSed spinel disk. In contrast, at the slow heating rate of 10 °C/min, the carbon contamination having disordered structures occurred only around the surface area. The carbon phases transform into high pressure CO/CO₂ gases by post-annealing in air and lead to pore formation along the grain junctions. The pore formation significantly occurs at the high heating rate due to the large amount of the contaminant carbon phases. This suggests that if once the carbon contamination was formed in the materials, it is very difficult to remove the carbon phases from the materials.     

High performance liquid chromatographic separation of diacylglycerol acetates to quantitate disaturated species of lung phosphatidylcholine

A high-performance liquid chromatographic (HPLC) separation of diacylglycerol acetates to quantitatite disaturated species of lung phosphatidylcholine (PC) was studied. The diacylglycerol acetates were applied on a reversed phase column, eluted by an isocratic solvent, acetonitrile/isopropanol/water (35:15:1, v/v/v) at a flow rate of 1 ml/min, and detected by differential refractometry (RI). This isocratic HPLC method was useful to separate disaturated species from the others of lung PC. The quantitative analysis of the molecular species separated by HPLC was studied by RI detection. Chroamtograms obtained by RI detection and radioactivity determination of diacylglycerol [³H]acetates prepared by [³H]acetic anhydride were almost identical. The RI detector responsed in the same degree for different, authentic standards of diacylglycerol acetates. The detection limit with RI detection was about 30 nmoles. Molecular species of PCs from human lung and carcinoma tissues were analyzed by this HPLC method. The contents of disaturated species were very similar to those reported previously. These results indicate that RI detection is very useful in the nmole range for the quantitative analysis among the molecular species containing disaturated species.     

Fabrication of a poly-Si thin-film transistor with storage capacitor

The fabrication process of a low-temperature poly-Si thin-film transistor (TFT) with a storage capacitor was studied. The atmospheric-pressure chemical-vapour deposited SiO₂ protected the buried indium tin oxide (ITO) from reduction by a pure H₂ plasma treatment that was essential for the effective improvement of the poly-Si TFT characteristics. Thus, a storage capacitor with an ITO (picture electrode)-SiO₂-ITO (buried common electrode) structure was successfully fabricated. The poly-Si TFT with a channel width/length W/L ratio of 5 drove a 3 pF storage capacitor in 2 μs, and it showed superior driverability for LCD use. The TFT also had good hold characteristics under illumination for the realization of grey-scale representation.     

Molecular size-dependent leakage of intracellular molecules from frog skeletal muscle fibers permeabilized with beta-escin

The permeability of beta-escin-treated cell membrane was characterized in terms of the permeant molecular size, by monitoring the leak of cytoplasmic molecules in frog skeletal muscle fibers. With a low concentration of beta-escin (5 microM), most of the cellular ATP was lost within 30-40 min (as revealed by rigor force generation), whereas a fluorescence-labeled dextran injected into the cytoplasm (approximately 10 kDa) and cytoplasmic proteins (14-80 kDa) slowly leaked out of the cell. A high concentration of beta-escin (50-100 microM) accelerated the leak of large molecules. Therefore, low concentrations of beta-escin may be used as a means of permeabilizing the cell membrane to relatively small molecules, while retaining a major fraction of the cellular macromolecules.     

Highly reliable testing of ULSI memories with on-chip voltage-downconverters

Two testing techniques for ultra-large-scale integrated (ULSI) memories containing on-chip voltage downconverters (VDCs) are described. The first in an on-chip VDC tuning technique that adjusts internal V_CC to compensate for the monitored characteristics of the process parameters during repair analysis testing. The second is an operating-voltage margin test, performed at various internal V_CC levels during the water sort test (WT) and the final shipping test (FT)     

Developmental changes in enzyme activities and in structural features of rat masticatory muscle mitochondria

The functional ability of a muscle is closely related to the activities of the mitochondria, which are energy-producing organelles in muscle cells. The development of the mammalian masticatory muscle progresses dramatically when feeding behavior changes from suckling to mastication, but it is unclear how the energy-producing systems of the mitochondria change. In this paper, the development of rat masticatory muscle mitochondria was investigated in terms of enzyme activities of the mitochondrial respiratory chain and the structural and numerical development of mitochondria, especially regarding the change in feeding behavior from suckling to mastication. Using isolated mitochondria from the masticatory muscle, we measured succinate dehydrogenase, NADH dehydrogenase, succinate-O2 oxidoreductase, and NADH-O2 oxidoreductase. These were found to be increased in the 15-day postnatal rat compared with the 0- to 10-day postnatal rat. The structural development of mitochondria was gradual in the 0- to 15-day postnatal rat. However, a notable increase was found in the cross-sectional area of mitochondria between 10 and 15 days postnatally. The number of mitochondria per muscle fiber was apparently constant during the same period. We demonstrated that the change in feeding behavior was well-correlated with an increase in mitochondrial enzyme activity, also supported by the early structural development of mitochondria.     

Prostaglandin E receptor subtypes in mouse osteoblastic cell line

PGE2 is one of the key molecules in the osteoblast. It is the major prostanoid in the bone, and its production is under the control of both systemic and local factors. PGE2 has been reported to have multiple actions in the osteoblast, such as growth promotion and cell differentiation. To better understand the action of PGE2 in the osteoblast, we determined the PGE receptor subtypes in MC3T3-E1, an osteoblastic cell line derived from the normal mouse calvaria. Northern blot analysis revealed that EP1 and EP4 subtypes are expressed in MC3T3-E1. In contrast, EP3 subtype was not detected by either Northern blot analysis or RT-PCR. The contribution of each subtype was evaluated by studying the effects of subtype-specific analogs on osteoblastic function at confluency and 5 days after confluency. An EP1 agonist, 17-phenyl-omega-trinor PGE2, increased DNA synthesis and decreased alkaline phosphatase activity. 11-Deoxy-PGE1, and EP2 and EP4 agonist, decreased DNA synthesis and increased alkaline phosphatase activity at both stages. Butaprost, an EP2-selective agonist, showed effects similar to those of 11-deoxy-PGE1 only at confluency. Another and more differentiated osteoblastic marker, osteocalcin production, was detectable and was stimulated by 11-deoxy-PGE1 only 5 days after confluency. The exposure of these cells to EP1 agonist changed the cell shape to a more fibroblastic appearance. These results indicate that EP1, EP4, and probably EP2 are present in MC3T3-E1 cells; EP1 promotes cell growth, and EP2 and EP4 mediate differentiation of the osteoblast. Furthermore, the decreased response to EP2-specific agonist 5 days after confluency suggests that the expression of PGE receptor subtype is dependent on the stage of osteoblastic differentiation. This is the first report to determine PGE receptor subtypes in the bone.     

Preparation of polyimide-epoxy composites

The formation of a three dimensional network of crosslinked epoxy leads all unmodified epoxies to have inherent brittleness and relatively low degradation temperatures. Polyimides, on the other hand, are widely used for applications that require high degrees of flexibility and thermal resistance. Here, we have focused on the preparation of epoxy systems cured with polyamic acids instead of traditional amino-group-containing hardening agents. The cure behavior and potential reaction mechanisms of EPON 828 resin and polyamic acid mixtures were evaluated by DSC and TGA. Thermal analysis showed a complex reaction sequence taking place in the mixture and also determined the extent of reaction of the polyamic acid with itself and the competitive reaction of the polyamic acid with the epoxy. The compositions of the mixtures were varied to see the dependence of the cure behavior on component concentrations. Solutions of the two components did not phase separate and also phase separation was not apparent either optically or microscopically in the cured samples. This phase behavior was attributed to a unique in situ reaction. A novel solvent system for the polyamic acid precursor was also used.     

Question hard, answer simply: A comment on Storms et al. (2003).

It seems clear that, for whatever reasons, the dementia of the Alzheimer type patient group (as well as other patient groups) exhibits behavior that is different from the normal control group. G. Storms, T. Dirikx, J. Saerens, S. Verstraeten, and P. P. De Deyn (2003) rightfully argue that the observed behavior (similarity judgments) does not tell us the source (cause) of the differences between the 2 groups. Rather, the focus of the study should be placed more on finding the ways the 2 groups are different. They also point out various methodological problems in some of the previous attempts to characterize the nature of the differences. Further methodological issues in G. Storms et al.'s study are examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)