خيارات البحث
النتائج 341 - 350 من 374
Estimation of physicochemical properties using supercritical fluid chromatography
1997
Sunol, S.G. | Mierau, B. | Serifoglu, I. | Sunol, A.K.
The selection of chromatographic techniques in determination of physicochemical properties over conventional static methods is due to quick data turnaround with such systems and readily available commercial equipment. Supercritical fluid chromatography is and can be applied to physicochemical property estimation and its use for this purpose has received considerable attention especially more recently. Moreover, some techniques that are used for determining properties of gas-solid systems using gas chromatography can easily be applied to supercritical fluid chromatography.
اظهر المزيد [+] اقل [-]The suitability of gastropods as biomarkers : Induction of ethoxy-, pentoxy- and benzoxyresorufin-O-dealkylase in limnetic gastropods via aroclor 1254 النص الكامل
1997
Meimberg, Harald | Schrenk, Christiane | Steinberg, Christian | Klarenberg, Albert | Kettrup, A. A.
The measurement and induction of mixed function oxyigenases (MFOs) of limnetic gastropods were investigated to estimate their suitability as biomarkers. A determination of MFO activities was performed through the measurement of ethoxyresorufin-O-dealkylase (EROD), pentoxy-(PROD) and benzoxyresorufin-O-dealkylase-activity (BROD). Optimal measuring conditions of these activities were investigated in preparations of the digestive gland of 4 species of limnetic gastropods. Results indicate that MFO-activity inhibiting substances are accumulating in the microsomal pellet, the fraction commonly used for the measurement of MFO-activities. Therefore, the fraction used for induction studies was the postmitochondrial supernatant (PMS). EROD, PROD, and BROD activity ofPlanorbis planorbis andPlanorbis carinatus were measured after a treatment with Aroclor 1254 for 1–17 days. Maximal induction of EROD and PROD were 6 and 10 times the value in the control group ofP. carinatus, respectively induction inP. planorbis was lower. BROD-activity could not been measured inP. planorbis. InP. carinatus, BROD-activity increased to a maximum of 2 times after traetment with Aroclor 1254. The level of induction of EROD-activity is comparable to results described in analog studies with fish.
اظهر المزيد [+] اقل [-]Accumulation of sulphur in and on Scots pine needles in the subarctic
1997
Manninen, S. (Oulu Univ. (Finland). Dept. of Biology and Botany) | Huttunen, S. | Kontio, M.
Possibilities for increased carbon sequestration through the implementation of rational forest management in Russia
1997
Shvidenko, A. (International Inst. for Applied Systems Analysis, Laxenburg (Austria).) | Nilsson, S. | Roshkov, V.
Metal extractability and availability in a soil after heavy application of either nickel or lead in different forms
1997
Nogales, R. (Estacion Experimental del Zaidin CSIC, Granada (Spain).) | Gallardo-Lara, F. | Benitez, E. | Soto, J. | Hervas, D. | Polo, A.
Metal-metal interactions in biological systems. Part 4. Steinernema carpocapsae (Steinernematidae) and Heterorhabditis bacteriophora (Heterorhabditidae) entomopathogenic nematodes
1997
Jaworska, M. (Hugon Kollataj Academy of Agriculture, Cracow (Poland). Dept. of Entomology) | Gorczyca, A. | Sepiol, J. | Szeliga, E. | Tomasik, P.
Effects of metals on the microbial mineralization of organic acids
1997
Brynhildsen, L. (Linkoeping Univ. (Sweden). Dept. of Water and Environmental Studies) | Rosswall, T.
Effect of copper smelting air pollution on the mites (Acari) associated with young Scots pine forests polluted by a copper smelting works at Giogow, Poland. 1. Arboreal mites
1997
Seniczak, S. (University of Technology and Agriculture, Bydgoszcz (Poland). Dept. of Ecology) | Dabrowski, J. | Dlugosz, J.
Sulphur and heavy metal concentrations in Scots pine bark in northern Finland and the Kola Peninsula
1997
Poikolainen, J. (Finnish Forest Research Inst., Muhos (Finland). Muhos Research Station)
Diagnosis of boron, fluorine, lead, nickel and zinc toxicity in citrus plantations in Villarreal, Spain
1997
Aucejo, A. (Valencia Univ., Burjassot (Spain). Dept. de Ingenieria Quimica) | Ferrer, J. | Gabaldon, C. | Marzal, P. | Seco, A.