Electrogenerated hypervalent iodine compounds as mediators in organic synthesis

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Super-visible codes

Upper bounds and constructions are given for super-visible codes. These are linear codes with the property that all words of minimum weight form a basis of the code. Optimal super-visible codes are summarized for small lengths and minimum distances.     

Arylesters of alkylsulfonic acids in sediments Part III of organic compounds as contaminants of the Elbe River and its tributaries

Sediments from the Elbe River and from its major tributaries are shown to be contaminated with arylesters of alkylsulfonic acids. Here we report on the structure elucidation and quantification of aryl esters of alkylsulfonic acids. Chromatographic separation and mass spectrometric properties are discussed. Congener-specific analyses revealed a highly similar pattern throughout the area investigated. Alkylsulfonic acid phenylesters were present at almost all sampling locations. Amounts ranged from 33 000 μg/kg near the industrial region of Bitterfeld to 15 μg/kg in wadden sea sediments. Concentrations of alkylsulfonic acid cresylesters were between 10–40% of the phenylesters, and fell below the detection limit only in the Elbe estuary. The presence of aryl esters of alkylsulfonic acids in all sediment samples analyzed indicates a widespread distribution of these compounds in the environment. Previous literature described these compounds erroneously as phenoxyalkanes. Received: 5 August 1997 / Accepted: 21 August 1997     

Sea surface temperature from AVHRR-2 data

Summary From the measurements in two channels of the 10 to 13 μm window region, the correction for the atmospheric absorption, useful to retrieve the sea surface temperature from satellite data, can be obtained. By using radiative-transfer model simulations, an up-to-date algorithm was developed, to retrieve the sea surface temperature from the AVHRR (advanced very high resolution radiometer) data. This algorithm has been compared with the algorithms found in the literature. A map of surface temperature in the Northern Adriatic Sea has been processed as an example of application of the algorithm developed. Visiting Scientist at the Joint Research Centre, Commission of the European Communities, 21020 ISPRA.     

NEAR-UV INDUCTION OF SISTER CHROMATID EXCHANGES UNDER AEROBIC AND ANAEROBIC CONDITIONS

Abstract— The induction of sister chromatid exchanges (SCE) and cell sensitivity in mouse myeloma cells (66.2 subclone of MPC11) by irradiation with monochromatic near-UV (365 nm) light were studied under aerobic and anaerobic conditions. Sister chromatid exchanges were studied using the fluorescence-plus-Giemsa technique, and sensitivity was determined by the ability of irradiated and nonirradiated control cells to form colonies in soft agar. Cells were found to be 16 times more sensitive to near-UV light under aerobic exposure, producing an F₃₇ value of 7 × 10⁴ J/m² compared to the F₃₇ value of 11.5 × 10⁵ J/m² under anaerobic conditions. The induction of SCE was also 12 times more efficient for aerobic irradiation than for anaerobic irradiation. The data suggest that the SCE-inducing potential of DNA lesions differs when near-UV irradiation is performed in the presence or absence of air. In addition, the DNA lesions responsible for lethality and also those lesions leading to SCE induction may differ under the two irradiation conditions.     

Effect of solvents on the selectivity of terbutylazine imprinted polymer sorbents used in solid-phase extraction

A solid-phase extraction sample preparation method using a molecularly imprinted polymer (MIP) selective for the triazine type pesticide terbutylazine has been developed. The method involves preconcentration from large volumes of water samples on a C18 disk coupled to selective clean-up on the MIP. The method has been optimised by studying the recovery and retention of terbutylazine and some other structurally related triazine derivates as a function of the selective washing solvent used. The effect of the water content of the selective washing solvent was also investigated on the recovery of the MIP. River water samples were analysed with the coupled technique, and efficient clean-up of the samples was observed.     

DEPENDENCE ON STAGE OF GROWTH OF MAMMALIAN CELL SENSITIVITY TO NEAR-UV IRRADIATION*

Abstract The variable sensitivity of exponentially growing mouse myeloma cells (66.2 subclone of MPC11) to monochromatic near-UV (365 nm) radiation was studied by determination of the relative cloning efficiency (i.e. survival) of cells in soft agar. Maximum sensitivity of the cells to near-UV light was found during the middle and late stages of exponential growth when the survival was only one-tenth of that during the early stage of growth. In addition, the shapes of near-UV survival curves changed with the stage of the cells irradiated. These data indicate that stages of growth can substantially alter the response of mammalian cells to near-UV radiation. These data further suggest the importance of testing the response of the cells throughout the growth employed in the experimental procedure.