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  • modification  (3)
  • Urinalysis  (2)
  • biogenesis  (2)
  • marine green alga  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 29 (1990), S. 745-747 
    ISSN: 0031-9422
    Keywords: Chlorophyceae ; Ulva pertusa ; fatty acids ; flavour ; long-chain aldehydes ; marine green alga ; protoplasts ; regeneration ; sterility test.
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0031-9422
    Keywords: Ulva pertusa ; Ulvaceae ; aldehydes ; fatty acids. ; flavour ; marine green alga
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0031-9422
    Keywords: (8Z, 11Z)-hexadecadienal ; Marine algae ; biogenesis ; fatty acids. ; long chain aldehyde-fo∞#x03BD;g activity ; pentadecanal ; volatile compounds
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 73 (2000), S. 449-456 
    ISSN: 1432-1246
    Keywords: Key words Acetone ; Biological monitoring ; Hexane ; 2 ; 5-Hexanedione ; Toluene ; Ethyl acetate ; Urinalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: To investigate whether metabolic interactions exist between hexane (HEX) and other solvents when co-exposed at the levels below occupational exposure limits. Methods: Workers, 219 men in ten workshops in total, volunteered to participate in the study. They were occupationally exposed to mixtures of HEX and one or more of toluene (TOL), ethyl acetate (EA) and acetone (ACE). Time-weighted average intensity of vapor exposures was monitored by diffusive personal sampling. `Free'- and `total'-2,5-hexanedione (HD) levels in the end-of-shift urine samples were determined by gas chromatography (GC) before and after acid hydrolysis of urine, respectively, and expressed as observed (HDob) or after correction for creatinine concentration (HDcr) or urine specific gravity (HDsg). Possible interaction was examined by multiple regression analysis (MRA), taking either free- or total-HD as a dependent variable, and the four solvent concentrations as independent variables. Results: In most cases, exposure intensity did not exceed the current occupational exposure limits even when additiveness was assumed. In addition that HEX was the most influential independent variable in all cases as expected, the MRA showed that, in cases of free-HD, ACE was also influential to HDob although weakly, but not to HDcr or HDsg. With regard to total-HD, ACE was weakly influential to HDob and HDsg, and EA also weakly to HDcr. The effect of ACE on free- or total-HD was not detected, however, when 22 men exposed only to HEX and ACE were subjected to the same analysis. Similarly, the effect of EA on total-HD was not observed among the remaining 197 men exposed to HEX, TOL and EA only. Conclusions: When the exposures were below occupational exposure limits, the free-HD levels in urine after HEX exposure will not be modified by co-exposures to TOL, EA or ACE.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1246
    Keywords: Key words Biological monitoring ; Blood analysis ; Diffusive sampling ; Head-space GC ; Tetrachloroethene ; Urinalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: The present study was initiated to examine a quantitative relationship between tetrachloroethene (TETRA) in blood and urine with TETRA in air, and to compare TETRA in blood or urine with trichloroacetic acid (TCA) in urine as exposure markers. Methods: In total, 44 workers (exposed to TETRA during automated, continuous cloth-degreasing operations), and ten non-exposed subjects volunteered to participate in the study. The exposure to vapor was monitored by diffusive sampling. The amounts of TETRA and TCA in end-of-shift blood and urine samples were measured by either head-space gas chromatography (HS-GC) or automated methylation followed by HS-GC. The correlation was examined by regression analysis. Results: The maximum time-weighted average (TWA) concentration for TETRA-exposure was 46 ppm. Regression analysis for correlation of TETRA in blood, TETRA in urine and TCA in urine, with TETRA in air, showed that the coefficient was largest for the correlation between TETRA in air and TETRA in blood. The TETRA in blood, in urine and in air correlated mutually, whereas TCA in urine correlated more closely with TETRA in blood than with TETRA in urine. The TCA values determined by colorimetry and by the GC method were very similar. The biological marker levels at a hypothetical exposure of 25 ppm TETRA were substantially higher in the present study than were the levels reported in the literature. Possible reasons are discussed. Conclusions: Blood TETRA is the best marker of occupational exposure to TETRA, being superior to the traditional marker, urinary TCA.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-5176
    Keywords: algae ; biogenesis ; distribution ; long chain aldehyde ; enzyme ; volatile compound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The long chain aldehyde-forming enzyme (LCAE) activity that catalyzes formation of long chain aldehydes, such as (8Z, 11Z, 14Z)-heptadecatrienal, (8Z, 11Z)-heptadecadienal, (8Z)-heptadermal, (7Z, 10Z, 13Z)-hexadecatrienal and pentadecanal from linolenic acid, linoleic acid, oleic acid and palmitic acid, in that order, occurs in a wide range of green, brown and red seaweeds. The LCAE activity increased with maturation of juvenile fronds of Enteromorpha sp. in culture. Thus, cultivation of seaweeds for flavor foods is of interest. The release of long chain aldehydes from the thallus into the medium was confirmed by a quantitative high performance liquid chromatography of volatile compounds, using a closed loop stripping technique, during the culture of the green alga, Ulva pertusa. This finding suggests physiological roles of long chain aldehydes and LCAE activity in marine ecosystems.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 272 (1994), S. 1620-1626 
    ISSN: 1435-1536
    Keywords: Zeolite ; modification ; chloroform ; adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Adsorption characteristics of chloroform from its aqueous solution on Na−Y and Li−Na−Y modified by SiCl4 were measured and compared with those on Na−ZSM-5 and Na-Mordenite. No adsorption occurred on Na−Y with high hydrophilicity, while the siliceous faujasites became capable of adsorption and its amount increased with increase in the Si/A1 ratio. Adsorption isotherms are of Langmuir type, suggesting that adsorption proceeds by pore filling. The adsorption amounts expressed in volume on Na−Y with high hydrophobicity corresponded to their pore volumes. Adsorption characteristics of chloroform from gaseous phase on Na−Y with different Si/A1 ratio were also measured. The adsorption capability decreased with increasing Si/A1 ratio. Immersional heats of zeolites into water or chloroform were measured in order to evaluate the surface affinity to both solvents. Immersional heats into water were almost constant (about 500 mJ·m−2) for zeolites with their Si/A1 ratio below 10. The heats decreased with an increase in the Si/A1 ratio above 10, then became almost constant (about 120 mJ·m−2) over 30 in their ratio. Heats of immersion of Na−Y series into chloroform were almost constant irrespective of their Si/A1 ratio, but decreased slightly when the ratio exceeded 20. Adsorption characteristics of chloroform could be well related to immersional heats into both solvents.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 272 (1994), S. 830-836 
    ISSN: 1435-1536
    Keywords: Zeolite ; modification ; surfactant ; adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Hydrophobic faujasite-type zeolites were prepared by the treatment of hydrophilic Na-Y4.6 with silicon tetrachloride (SiCl4) by way of dealumination-silicon exchange reaction. Hydrophilic-hydrophobic characters of these zeolite surfaces were evaluated by measurements of immersional heats into water orn-hexane. Adsorption rates of sodium dodecylsulfate (SDoS) on these zeolites from its aqueous solution and their adsorption characteristics were investigated, and compared with those on ZSM-5 with various Si/Al ratios. The adsorption ability of SDoS into zeolite micropores developed on the zeolite only when it was modified to some extent. The adsorption rates of SDoS were very slow and proved to be affected by molecular diffusion in zeolite pores. They depended on hydrophilic-hydrophobic character of zeolites as well as on pore structures. Adsorption isotherms of SDoS were of Langmuir type, which indicates that the adsorption occurred typically into zeolite pores. Adsorbed amount of SDoS depended on the balance of hydrophilic-hydrophobic character and number of cation site of zeolite surfaces, and had a maximum in case of ZSM-5 zeolites.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 273 (1995), S. 787-792 
    ISSN: 1435-1536
    Keywords: Zeolite ; modification ; surfactant ; adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Adsorption characteristics of anion-, cation- and nonion-type surfactants and phenol from their aqueous solution on Na-Y zeolites modified by SiCl4 treatment and NA-ZSM-5 zeolites with several Si/Al ratios were measured. Surfactants used were sodium dodecylbenzenesulfonte (DBS), laurylpyridinium chloride (LPC), polyoxyethylenenonylphenylether (POENPE) and phenol. Adsorption of surfactants was enhanced by SiCl4 treatment of Na-Y, which indicates an important role of the hydrophilic-hydrophobic character in the adsorption. Adsorption isotherms were in general of Langmuir type and adsorbed amount depended on the Al/(Si+Al) or Si/Al ratio of zeolite frameworks. In case of DBS adsorption of Na-ZSM-5 series, adsorption occurred only on the outer surface due to steric hindrance. LPC adsorption abilities were observed on even hydrophilic zeolites and were ascribed to ion exchange effect. In case of phenol adsorption on hydrophobic Na-Y, the adsorption isotherm was of Type V according to BDDT classification.
    Type of Medium: Electronic Resource
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