51 research outputs found

    Disinfectant Effects of Ultraviolet Irradiation on Fish Pathogens in Hatchery Water Supply

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    Disinfectant effects of U.V. irradiation were examined on cell suspensions of 5 species of fish pathogenic bacteria, and a punched agar medium disk covered with 10 strains of aquatic fungi and 7 strains of cell free fish pathogenic viruses. 99 .99 % or more of the viable bacterial cells were effected by U.V. treatment of more than 2.2 × 10^3 μW•sec/cm2 U.V. dosage. The hyphae of aquatic fungi showed relatively lower susceptibility to U.V. irradiation, that which inhibited the growth of hyphae was 1.5 - 2.5 × 10^5 μW•sec/cm2. Fish viruses, IHNV, HRV, OMV, CCV and H. salmonis were found to be sensitive to U.V. irradiation, and a 99 % or more infectively decrease (ID99) was 1.0 – 3.0 × 10^3 μW•sec/cm2. Susceptibility of IPNV and CSV were found to be low, ID99 measured 1.0 – 1.5 × 10^5 μW•sec/cm2. The infectivity of IHNV, in virus contaminated river water and IHNV contaminated pond water, measured by the molecular filtration method was 0.56 and 5.6 TCID50/l, respectively U.V. treatment of river water with 10^3 μW•sec/cm2 dosage could prevent an IHN outbreak. Furthermore, U.V. treatment of the hatchery water supply also decreases the visible bacterial counts and fungi infection rates of salmonid eggs.Second Asian Fisheries Forum. 17-22 April 1989. Tokyo, Japan

    Ellagitannins of Davidia involucrata. I. Structure of Davicratinic Acid A and Effects of Davidia Tannins on Drug-Resistant Bacteria and Human Oral Squamous Cell Carcinomas

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    We isolated a new ellagitannin, davicratinic acid A (5), together with four known ellagitannins, davidiin (1), granatin A (2), pedunculagin (3), and 3-O-galloylgranatin A (4), from an aqueous acetone extract of dried Davidia involucrata leaves. The known ellagitannins were identified based on spectroscopic data. The structure of davicratinic acid A (5), a monomeric ellagitannin possessing a unique, skew-boat glucopyranose core, was established based on spectroscopic data. Additionally, we examined the effects of several tannins with good yields from this plant on drug-resistant bacteria and human oral squamous cell carcinomas, and found that davidiin (1) exhibited the most potent antibacterial and antitumor properties among the tannins examined

    Mutual Exclusivity in the Synthesis of High Crystallinity and High Yield Single-Walled Carbon Nanotubes

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    We report the mutually exclusive relationship between carbon nanotube (CNT) yield and crystallinity. Growth conditions were optimized for CNT growth yield and crystallinity through sequential tuning of three input variables: growth enhancer level, growth temperature, and carbon feedstock level. This optimization revealed that, regardless of the variety of carbon feedstock and growth enhancer, the optimum conditions for yield and crystallinity differed significantly with yield/crystallinity, preferring lower/higher growth temperatures and higher/lower carbon feedstock levels. This mutual exclusivity stemmed from the inherent limiting mechanisms for each property
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