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  • 1
    Electronic Resource
    Electronic Resource
    Synthese von Glucuroniden der Flavonoid-Reihe, II. Isolierung von Kämpferol-3-β-D-glucuronid aus Euphorbia esula L. und seine Synthese (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 3678-3683 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Glucuronides in the Flavonoid-Series, II. Isolation of Kaempferol-3-β-D-glucuronide from Euphorbia esula L.From the aerial parts of Euphorbia esula L. (Euphorbiaceae) a flavone-glycoside was isolated and identified as 3,5,7,4′-tetrahydroxyflavone(kaempferol)-3-β-D-glucuronide (8). Its structure was confirmed by coupling of 7,4′ -dibenzylkaempferol with methyl(tri-O-acetyl-α-D-glucopyranosyl bromide)-uronate, followed by total acetylation, debenzylation and saponification to 8.
    Notes: Aus den oberirdischen Teilen von Euphorbia esula L. (Euphorbiaceae) wurde ein Flavonglykosid isoliert und als 3.5.7.4′-Tetrahydroxy-flavon(Kämpferol)-3-β-D-glucuronid (8) identifiziert. Seine Struktur wurde durch Kupplung von 7.4′-Dibenzyl-Kämpferol mit α-Acetobromglucuronsäure-methylester, Darstellung des Vollacetats, Entbenzylierung und Verseifung zu 8 bewiesen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701031132
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  • 2
    Electronic Resource
    Electronic Resource
    Catalytic conversion of a diene into deeply colored polymersPresentedat the International Congress of Pure and Applied Chemistry, September, 1951. (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 157-161 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cyclopentadiene can be catalytically converted into a deep red polycyclopentadienetrichloroacetic acid adduct (I). Oxidation and hydrogenation experiments show that each repeating unit of (I) contains one double bond. Other observations, including spectroscopic and electrochemical measurements indicate that these double bonds are conjugated, and that this polymerization involves the migration of hydrogen atoms. The kinetics of the formation of (I) are investigated and some results of these measurements, together with those pertaining to the alkaline hydrolysis of (I), make it probable that the initiation step is in acid-catalyzed esterification of the diene and that the final polymer is an ester. Colloid chemical properties of (I) are described.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080202
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  • 3
    Electronic Resource
    Electronic Resource
    Sample introduction in capillary supercritical fluid chromatography using sequential density gradient focussing and solvent venting (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 3 (1991), S. 435-442 
    Details
    ISSN: 1040-7685
    Keywords: solvent vent ; density gradient focussing ; capillary columns ; supercritical fluid chromatography ; sample introduction ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A technique was developed for large volume sample introduction in capillary supercritical fluid chromatography. A 20-cm length of 200-μm i.d. capillary tubing was used as precolumn. The precolumn temperature could be easily controlled by passing an electrical current through an electrically conductive paint coated on its outer surface. During injection, the sample solvent was vented from the precolumn with CO2 (gas) at 32 atm, while the precolumn was kept at room temperature. Solutes were transferred onto the head of the analytical column as a narrow band by density gradient focussing, which was established with (a) a temperature gradient along the precolumn, (b) a rapid expansion of CO2 from supercritical fluid to gas, and (c) a temperature difference between the precolumn and the analytical column. This injection approach minimized solute mass discrimination and could be easily performed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220030508
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  • 4
    Electronic Resource
    Electronic Resource
    Supercritical fluid extraction/gas chromatography with thermal desorption modulator interface and nitro-specific detection for the analysis of explosives (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 7 (1995), S. 23-28 
    Details
    ISSN: 1040-7685
    Keywords: supercritical fluid extraction ; gas chromatography ; thermal desorption modulation ; explosives ; chemiluminescence detection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Supercritical fluid extraction (SFE) can greatly reduce the sample preparation time of analytes in solid matrices. The on-line coupling of SFE with high-speed gas chromatography (GC) can further reduce the total analysis time. SFE has been coupled to GC with a thermal desorption modulator (TDM) interface. A thermal energy analyzer (TEA), a chemiluminescence detector which is specific for nitro and nitroso compounds, has been coupled to the system to analyze explosives in soil samples.The use of organic modifiers to increase the solvation power of carbon dioxide was necessary for the extraction of various explosives, and did not adversely affect the performance of the system. Thermally labile compounds, however, such as the nitrate esters, were shown to decompose in the modulator before the chromatographic separation.This method allows for the rapid analysis of relatively volatile and thermally stable nitro compounds from solid matrices. The system can be used for screening small samples in short periods of time. Total analysis can be completed in less than 10 minutes and requires only 200 mg of soil. The minimum detectable quantity for the analysis of 2,4-DNT was found to be 2.6 ppb in an actual soil sample.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220070104
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  • 5
    Electronic Resource
    Electronic Resource
    High-speed, thermally modulated SFE/GC for the analysis of volatile organic compounds in solid matrices (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 4 (1992), S. 199-208 
    Details
    ISSN: 1040-7685
    Keywords: supercritical fluid extraction ; high speed gas chromatography ; open tubular columns ; thermal modulation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A coupled supercritical fluid extraction (SFE) and high-speed gas chromatography (GC) system was developed which permits simultaneous sample extraction and analysis. A thermal desorption modulator at the head of a 50-μm i.d. capillary column was used as an interface between the SFE and GC. The extraction fluid was first split between the modulator and a waste collection vessel. The substances introduced into the modulator were concentrated in the stationary phase and then released as a sharp injection pulse to the analytical column by electrical resistance heated thermal desorption. The modulator was operated at 10-s time intervals, which generated consecutive concentration pulses to the column. These concentration pulses were separated into individual chromatograms by high-speed GC. A set of chromatograms could be generated while the extraction proceeded. With this system, the extractant was sampled continuously so that the SFE process could be monitored in real time for selected components. Quantitative results could be extrapolated before extraction was complete from curves obtained by signal averaging of segmented chromatograms from the set.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220040304
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  • 6
    Electronic Resource
    Electronic Resource
    Multi-element selective radio frequency plasma detector for capillary gas chromatography (1988)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 11 (1988), S. 75-81 
    Details
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Element selective detection ; Radio frequency plasma ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A radio frequency plasma detector for element specific detection in gas chromatography is described. The detector is comprised of a radio frequency (300 kHz) discharge between electrodes in helium, and utilizes a low-resolution emission spectrometer to monitor selected spectral emission lines produced when the helium discharge decomposes and excites the atomic constituents in the chromatographic column effluent. The spectrometer is tuned to an atomic emission line in the near-infrared portion of the spectrum, and the emission intensity from the discharge region of a selected line is used to monitor the concentration of the element producing that line. Acceptable detector sensitivity was achieved by the use of a high-throughput optical system. Selectivity was achieved by a combination of correct line selection, plasma and carrier gas purification, and plasma gas doping.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240110120
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  • 7
    Electronic Resource
    Electronic Resource
    In vitro and in vivo metal ion release (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 321-338 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A series of experiments was conducted to study in vitro and in vivo metal ion release and the urine excretion of metal ions. Metal salts were injected and urine analyzed. Anodic potentials were applied to stainless steel and cobalt-chromium-molybdenum (CCM) specimens to cause an acceleration of corrosion rates. Corrosion experiments were done in saline, 10% serum and in a subcutaneous space in hamsters. Corrosion rates were determined by measurements of weight loss and calculations of net charge transfer. Metal ion concentrations were determined with graphite furnace atomic absorption spectroscopy, and were calculated from total charge using Faraday's law. The results with stainless steel showed that the weight loss and metal ion release from stainless steel in vitro and in vivo can be calculated using Faraday's Law, assuming release in proportion to alloy composition. The results with CCM indicated that release rates in vitro can be used to determine the proportionality of release in vivo. All the nickel and most of the cobalt was rapidly excreted, while less than 50% of the chromium was excreted. The excretion of metals following salt injection or in vivo corrosion were very similar.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820220406
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  • 8
    Electronic Resource
    Electronic Resource
    Inhibition of juvenile hormone III biosynthesis in cockroach corpora allata by interference with the S-adenosylmethionine-dependent transmethylation (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 5 (1987), S. 179-188 
    Details
    ISSN: 0739-4462
    Keywords: juvenile hormone synthesis ; S-adenosylmethionine ; S-adenosylhomocysteine hydrolase ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The synthesis of juvenile hormone-III by corpora allata of the cockroach Diploptera punctata is dependent under in vitro conditions upon a supply of exogenous methionine. Radiolabelled S-adenosylmethionine was identified by HPLC in extracts of corpora allata incubated with either [methyl-3H]methionine or [35S]methionine. Juvenile hormone (JH) synthesis by intact glands in vitro was inhibited by cycloleucine and selenomethionine, but this inhibition could be relieved by increasing the concentration of methionine. S-adenosylhomocysteine or sinefungin had little or no inhibitory effect on JH synthesis by intact glands, but 5′-deoxy-5′-methylthioadenosine was inhibitory. Adenosine and homocysteine synergistically inhibited JH synthesis. These results show that JH-III synthesis by intact glands can be inhibited by interfering with the S-adenosylmethionine-dependent transmethylation, and suggest that the product and inhibitor of that reaction, S-adenosyl-homocysteine, is rapidly hydrolyzed to adenosine and homocysteine in the corpora allata.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940050304
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