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  • 11
    Electronic Resource
    Electronic Resource
    Two Isoxazolidines (1996)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 52 (1996), S. 486-489 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The crystal structures of trans-phenyl 2-phenyl-1,6-dioxa-2-azaspiro[4.4]non-3-yl ketone, C19H19NO3, and (3α,3aα,6aα)-hexahydro-2-phenylfuro[3,2-d]isoxazol-3-yl phenyl ketone, C18H17NO3, are reported. In both compounds, the isoxazolidine rings adopt envelope conformations in which the O atom is bent out of the approximate plane of the other four ring atoms. Modest to negligible endo selectivities were confirmed in 1,3-dipolar cycloadditions of benzoylmethyleneaniline N-oxide with enol ethers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270195013692
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  • 12
    Electronic Resource
    Electronic Resource
    Determination of terbacil in soil by gas-liquid chromatography with63Ni electron capture detection (1977)
    Springer
    Bulletin of environmental contamination and toxicology 18 (1977), S. 83-88 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Summary A method is described for the determination of terbacil residue in soil. The herbicide residue is extracted with 1.5% NaOH, partitioned into an organic phase and subsequently cleaned up by passing through a Florisil column. Extract is analyzed by gas-liquid chromatography using a63Ni electron capture detector. The procedure has a sensitivity of about 0.01 ppm, based on a 20 g sample. The method was used for the analysis of terbacil residues in the field treated soil samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01686310
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  • 13
    Electronic Resource
    Electronic Resource
    Improved diffusion methods for determination of inorganic nitrogen in soil extracts and water (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 413-420 
    Details
    ISSN: 1432-0789
    Keywords: Key words Ammonium analysis ; 15N ; Nitrate ; Nitrite ; Inorganic N ; Soil extract diffusion method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Diffusion methods previously developed for inorganic-N analysis of soil extracts were modified to improve reliability, increase the dynamic range, extend the scope of applications, and simplify the processing of samples for N-isotope analysis. In these methods, the soil extract is treated with MgO, or MgO plus Devarda‘s alloy, in a 473-ml (1-pint) wide-mouth Mason jar to convert NH4 +-N, NO3 –-N, and/or NO2 –-N to NH3-N. The NH3 thereby liberated is collected in H3BO3-indicator solution in a Petri dish suspended from the Mason-jar lid and determined quantitatively by acidimetric titration. With the modifications described, analyses can be performed on 10- to 100-ml samples of water, 0.5MK2SO4, 1MKCl, 2MKCl, or 4MKCl, at temperatures between 20 and 30°C. Recovery from 10 or 20ml was quantitative in 18–80h with up to 4mgN; recovery from 50 or 100ml was quantitative in 3–13 days with up to 2mgN. Removal of H3BO3 for N-isotope analysis by the Rittenberg process was effected using methanol. Mason-jar diffusion methods are much simpler and more convenient than conventional steam distillations. Comparative studies showed that quantitative determinations are more accurate and precise by diffusion than by distillation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050266
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  • 14
    Electronic Resource
    Electronic Resource
    Nitrogen fertilizers promote denitrification (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 211-220 
    Details
    ISSN: 1432-0789
    Keywords: Key words Denitrification ; Fertilizer efficiency ; 15N ; Labelled dinitrogen ; Nitrification ; Nitrous oxide ; Urea ; Waterlogged soil ; Water-soluble organic carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A laboratory study was conducted to compare the effects of different N fertilizers on emission of N2 and N2O during denitrification of NO3 – in waterlogged soil. Field-moist samples of Drummer silty clay loam soil (fine-silty, mixed, mesic Typic Haplaquoll) were incubated under aerobic conditions for 0, 2, 4, 7, 14, 21, or 42 days with or without addition of unlabelled (NH4)2SO4, urea, NH4H2PO4, (NH4)2HPO4, NH4NO3 (200 or 1000 mg N kg–1 soil), or liquid anhydrous NH3 (1000 mg N kg–1 soil). The incubated soil samples were then treated with 15N-labelled KNO3 (250 mg N kg–1 soil, 73.7 atom% 15N), and incubation was carried out under waterlogged conditions for 5 days, followed by collection of atmospheric samples for 15N analyses to determine labelled N2 and N2O. Compared to samples incubated without addition of unlabelled N, all of the fertilizers promoted denitrification of 15NO3 –. Emission of labelled N2 and N2O decreased in the order: Anhydrous NH3〉urea〈$〉\gg〈$〉 (NH4)2HPO4〉(NH4)2SO4≃NH4NO3≃NH4H2PO4. The highest emissions observed with anhydrous NH3 or urea coincided with the presence of NO2 –, and 15N analyses indicated that these emissions originated from NO2 – rather than NO3 –. Emissions of labelled N2 and N2O were significantly correlated with fertilizer effects on soil pH and water-soluble organic C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050233
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  • 15
    Electronic Resource
    Electronic Resource
    14C-Residues of Trifluralin in a Soil and Their Uptake by Carrots (1997)
    Springer
    Bulletin of environmental contamination and toxicology 59 (1997), S. 58-64 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001289900443
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  • 16
    Electronic Resource
    Electronic Resource
    Determination of linuron residue in soil (1975)
    Springer
    Bulletin of environmental contamination and toxicology 13 (1975), S. 602-610 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01685187
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  • 17
    Electronic Resource
    Electronic Resource
    Determination of paraquat residues in food crops by gas chromatography (1975)
    Springer
    Bulletin of environmental contamination and toxicology 14 (1975), S. 745-749 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Summary A method is described for determining paraquat residues in lettuce, carrots and onions. The procedure is based on the extraction of the sample with 5N H2SO4 and catalytic hydrogenation of the acid extract. This is followed by column cleanup on alumina and subsequent determination by gas chromatography. Recoveries of paraquat added to lettuce, carrots and onion at 0.5, 0.1, and 0.05 ppm were between 75 to 86%, with maximum standard error of 4%. The lower limit of this method is in the 0.05 ppm range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01685252
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  • 18
    Electronic Resource
    Electronic Resource
    A precise method for the assessment of tibial ultrasound velocity (1996)
    Springer
    Osteoporosis international 6 (1996), S. 1-7 
    Details
    ISSN: 1433-2965
    Keywords: Osteoporosis ; Ultrasound velocity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We assessed a method for the measurement of ultrasound velocity in cortical bone of the human tibia using a probe designed to minimize the effects of surrounding soft tissues. Of four different measurement values, the maximum velocity (average of the five highest readings) gave the lowest errors of reproducibility in relation to the population variance (standardized coefficient of variation=1.8%). The maximum velocity varied according to the tibial site measured and for practical reasons the mid-tibial site was chosen for further study. The short-term intra- and inter-observer reproducibilities (coefficients of variation) were 0.35% (n=22) and 0.50% (n=27) respectively. Long-term reproducibility over 4 months in 31 subjects was 0.68%. There was no significant difference in maximum ultrasound velocity between the dominant and non-dominant tibia in 78 women (3764±209 vs 3763±199 m/s). Tibial ultrasound velocity was significantly higher in 73 premenopausal women (3999±102 m/s) than in 129 women referred for assessment of postmenopausal osteoporosis (3780±168 m/s), 26 women with steroid-induced osteoporosis (3790±188 m/s) and 4 women with hyperparathyroidism (3575±261 m/s). In premenopausal women, ultrasound velocity did not correlate significantly with age, height, weight or body mass index. In women with postmenopausal osteoporosis, ultrasound velocity decreased with age after the menopause (r=−0.47,p〈0.0001) and body weight exerted a weaker protective effect. The apparent annual decrease in velocity with age in postmenopausal osteoporosis (8.5 m/s) was comparable to the error of reproducibility. We conclude that the technique for measuring tibial ultrasound velocity is highly reproducible in relation to the distribution of values in the population and is sensitive to age- and osteoporosis-induced changes in bone. Further studies are required to examine its relationship to other indices of skeletal status to determine the biological and clinical relevance of the technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01626530
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  • 19
    Electronic Resource
    Electronic Resource
    Characterization of uronic-acid-rich inhibitor of calcium oxalate crystallization isolated from rat urine (1995)
    Springer
    Urological research 23 (1995), S. 95-101 
    Details
    ISSN: 1434-0879
    Keywords: Nephrolithiasis ; Calcium oxalate ; Chromatography ; Uronic-acid-rich protein ; Inter-α-trypsin inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human urine contains several macromolecules which inhibit calcium oxalate crystallization. Uronic-acid-rich protein (UAP), a glycoprotein with a molecular weight of approximately 35 kDa, is one such inhibitor. Here we report the characterization of UAP extracted from rat urine using three chromatographic steps including diethylaminoethanol (DEAE)-Sephacel, Sephacryl S-300 and Mono Q column and compare it with human UAP. The molecular weight of rat UAP (UAPr) is similar to that of human UAP (UAPh), being approximately 35 kDa as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Their amino acid compositions are identical, they contain a high percentage of aspartic and glutamic acids and they react positively in the carbazole reaction, suggesting that they contain uronic acid. The inhibitory activities of UAPh and UAPr were assayed on a calcium oxalate crystallization system in vitro using [45Ca]calcium chloride. Both exert a strong inhibition, suggesting that UAPr, like UAPh, plays an important role in preventing and reducing calcium oxalate crystallization in the urine. On Western blot analysis, both UAPh and UAPr immunoreact with inter-α-trypsin inhibitor (ITI) antibody. Nevertheless, using the Ouchterlony immunodiffusion technique, there was no precipitation line between ITI antibody and UAP. Therefore, we hypothesize that UAP is related to ITI and that they may have the same epitope but are not completely identical. We conclude that UAP belongs to the ITI superfamily of macromolecules which contribute to the regulation of the calcium oxalate crystallization process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307939
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  • 20
    Electronic Resource
    Electronic Resource
    Calcium oxalate crystal interaction with renal tubular epithelium, mechanism of crystal adhesion and its impact on stone development (1995)
    Springer
    Urological research 23 (1995), S. 71-79 
    Details
    ISSN: 1434-0879
    Keywords: Calcium oxalate ; Nephrolithiasis ; Basement membrane ; Kidney stone ; Crystallization ; Hyperoxaluria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The interaction between renal epithelial cells and calcium oxalate (CaOx) crystals and/or oxalate ions plays a critical role in the formation of urinary stones. Epithelial cells respond to hyperoxaluria and the presence of CaOx crystals in the kidneys by increased enzymuria and internalization of the crystals. Crystal cell interaction results in movement of crystals from the luminal to the basolateral side between the cells and the basement membrane. Once beneath the epithelium, crystals adhere to the basement membrane and become anchored inside the kidneys. Crystals anchored to basement membrane of the peripheral collecting duct aggregate with other crystals and move through an eroding epithelium to the papillary surface, furnishing an encrustation platform or a nidus for future development of a kidney stone. Thus interaction between renal epithelial cells and CaOx crystals and/or oxalate ions is an essential element in the development of urinary stone disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307936
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