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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 51 (1979), S. 783-784 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 147 (1996), S. 389-407 
    ISSN: 1420-9136
    Keywords: Monitoring of microearthquakes ; salt diapir ; seismotectonics of Provadia (Bulgaria)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract By analysis of microtremors recorded with digital seismological monitoring equipment near the Provadia salt diapir (Bulgaria), two groups of events showing different characteristics have been detected in the vicinity of the salt production area. The first group of events has low magnitudes and is located at a distance of about 1 km from the top of the salt diapir. These events show low stress drops. The second group of tremors is located outside the salt diapir. The corresponding magnitudes and stress drops are larger. The first class of events seems to be related to processes at the contour of the salt leaching caverns, whereas the origin of the second group seems to be connected with stress redistribution processes around the salt body. Based on this analysis, the tectonic model of the Provadia salt diapir has been modified.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 141 (1993), S. 221-247 
    ISSN: 1420-9136
    Keywords: Experimental ; plagioclase ; diagenesis ; porosity ; permeability ; dissolution ; precipitates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Dissolution of plagioclase under the physical conditions at shallow to intermediate burial depths is a prime candidate for secondary porosity generation in feldspathic siliciclastic sediments. The diagenetic behavior of granular aggregates of plagioclase feldspar and quartz has been investigated by experimentation performed in a Bridgeman-type pressure vessel. The experiments, each of two weeks duration, simulated pressure-temperature conditions approximating 3.5 km burial depth. By using a double-acting pore-fluid reservoir, solutions of various chemistries were cycled through samples composed of oligoclase or labradorite feldspar and quartz (90:10 wt% respectively). Scanning electron microscope analysis of the post-experiment samples reveals dissolution features and precipitated products. Dissolution voids of ∼10 microns occur typically in areas of maximum stress such as crack-tips and grain contacts. Dissolution on a larger scale is exemplified by topographical smoothing of grain su faces. The dissolved species are subsequently reprecipitated as Ca-enriched overgrowths (possibly zeolites) and clays. These precipitates are found individually on the scale of 10 microns and collectively as surface coatings on both feldspar and quartz grains. Atomic absorption spectroscopic analyses of the pore fluid suggest that the fluid chemistry is consistent with the observed experimental precipitates. These experiments show that clay coatings are unnecessary precursors to grain surface dissolution and that the diagenetic precipitation is not mineral selective. Also, the mass transfer of the dissolved species appears to be localized because grains displaying both dissolution and precipitation features are commonplace. Volume changes due to mineral transformation/alteration may increase secondary porosity if the dissolved species produced from dissolution are only partially involved in reprecipitation and the remaining dissolved material is flushed out by the pore fluids. However, if the mass transfer is primarily local then permeability would significantly decrease as precipitates may choke the pore throats.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1440
    Keywords: Urolithiasis subgroups ; Parathyroid hormone ; Blood and urine ; Cyclic AMP ; Cyclic GMP ; Nephrogenous nucleotides ; Urolithiasis-Untergruppen ; Parathormon ; Blut und Urin ; Zyklisches AMP ; Zyklisches GMP ; Nephrogene Nukleotide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei Gesunden (n=34) und Urolithiasis-Patienten mit den verschiedenen definierten metabolischen Untergruppen, einschließlich primärer Hyperparathyreoidismus (pHPT), wurden Parathormon (PTH) mittels zwei verschiedenen Antikörpern, sowie zyklische Nukleotide (cAMP; cGMP im Urin und Plasma studiert, außerdem deren nephrogene Komponente berechnet. Bei Nicht-pHPT-Steinkrankheit (=sog. idiopathische Form) war das nephrogene cAMP (2 h-Nüchternurin) bei der normocalciurisch verlaufenden Mehrheit (n=60) signifikant niedriger als normal, und auch in den anderen Untergruppen (absorptive Hypercalciurie,n=15; renale Hypercalciurie,n=23; Harnsäure-Lithiasis,n=17; Harnsäure/Calciumoxalat-Lithiasis,n=12) waren die Medianwerte niedriger als jener der Kontrollgruppe. Umgekehrt ist nephrogenes cAMP bei pHPT (n=20) stark erhöht, und nur bei dieser Störung war nephrogenes cGMP (2 h-Urin) ebenfalls erhöht. Die gesamte Nukleotid-Produktion (=Summe der nephrogenen Anteile von cAMP und cGMP) ist bei normocalciurisch verlaufender Steinkrankheit signifikant erniedrigt, bei pHPT erhöht. Ausgenommen hohes cAMP bei pHPT sind die Plasma-Nukleotide nicht verschieden. Steinpatienten (idiopathisch und pHPT) haben gemeinsam ein signifikant niedrigeres Serum-Phosphat und eine niedrigere Phosphatschwelle als Gesunde. Ausgenommen pHPT sind die Unterschiede in allen Gruppen beim Serum-Gesamtcalcium nur minutiös, ionisiertes Calcium ist bei renaler Hypercalciurie innerhalb des Normbereiches mäßig erhöht. PTH ist in allen Untergruppen der idiopathischen Lithiasis entweder normal bis niedrig (assay für intaktes Hormon) oder in einigen (absorptive und renale Hypercalciurie, alternativ Harnsäure oder Calcium-Oxalat-bildende Patienten) gering, aber signifikant erhöht (assay für mittlere bioinaktive Hormonregion). Mit den gleichen Bestimmungsmethoden ist das mediane PTH bei operativ bewiesenem pHPT um Faktor 8 bzw. 3 höher als bei gesunden Kontrollen. Aus den Ergebnissen wird gefolgert, daß a) die idiopathische Harnsteinkrankheit mit normaler bis niedriger renaler Bioaktivität der Nebenschilddrüsen einhergeht und diese Patienten bei normal-niedrigem Urin-cAMP eine niedrige renale Phosphatschwelle unbekannter Ätiologie aufweisen; b) das bei drei Untergruppen erhöhte Serum-PTH, gemessen mit einem Antikörper mit vorrangiger Erkennung der bio-inaktiven mittleren Hormonregion, nicht mit dem gleichzeitig normalen Urin- bzw. nephrogenen cAMP dieser Gruppen übereinstimmt, wohl aber mit normalem oder niedrigem PTH, gemessen mit einem assay, der alle Anteile des menschlichen Hormons erkennt; c) die Aktivität der tubulären Guanylat-Zyklase bei pHPT wahrscheinlich gesteigert ist, nicht jedoch in Abwesenheit von Hypercalcämie oder größerem PTH-Exzeß (übrige Gruppen).
    Notes: Summary In healthy controls (n=34) and in the various metabolically defined subgroups of urolithiasis patients, including primary hyperparathyroidism (pHPT), parathyroid hormone (PTH) was studied using two different antisera, as were the cyclic nucleotides (cAMP; cGMP) and related variables in both urine and plasma; in addition, the nephrogenous components of the cyclic nucleotides were also determined. In nonpHPT (so-called idiopathic) stone disease, nephrogenous cAMP (2-h fasting urine) was significantly lower than normal in the normo-calciuric majority (n=60), and also lower than normal (medians) in all the other subgroups (absorptive hypercalciuria,n=15; renal hypercalciuria,n=23; uric acid lithiasis,n=17; uric/calcium oxalate lithiasis,n=12). In contrast, it was significantly elevated in pHPT (n=20), and only in this latter condition was nephrogenous cGMP (2-h urine) elevated. The total nucleotide production (sum of nephrogenous cAMP + nephrogenous cGMP) is again significantly lower only in normo-calciuric calcium stone disease. Except for high values in pHPT, no differences in plasma nucleotides are observed. Stone patients (idiopathic and pHPT) have significantly lower-than-normal serum phosphate and phosphate threshold in common. With the exception of pHPT, the differences in serum calcium are only minute, while ionised calcium is moderately elevated within the normal range in the serum of renal hypercalciuria patients. In all subgroups of idiopathic lithiasis, PTH is either normal to low (intact hormone assay), or slightly but significantly elevated in three subgroups (absorptive and renal hypercalciuria, patients alternately forming uric acid or calcium oxalate stones), when measured in an assay recognizing only a bioinactive hormone fragment (mid-portion assay). In surgically proven pHPT, median PTH established with the same two assays, is elevated by a factor of 8 (intact hormone assay), or 3 (mid-portion assay) in comparison with healthy controls. From the results it is concluded that a) idiopathic urolithiasis is accompanied by normal or low renal bioactivity of the parathyroid glands in the presence of a low renal phosphate threshold concentration; b) the elevated serum PTH in three idiopathic subgroups measured with an antibody with recognition largely of the bioinactive mid-portion of the hormone, is not in accordance with the simultaneously normal or low urinary and nephrogenous cAMP of these individuals, but is in accord with the normal or low serum PTH measured with an antibody recognizing all regions of the human hormone; c) the activity of tubular guanylate cyclase in pHPT is probably increased, but not in situations where both hypercalcemia and a considerable excess of parathyroid hormone are absent (remaining groups).
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 7 (1989), S. 289-296 
    ISSN: 1432-0789
    Keywords: Most probable number method ; Absorbance method ; LC50 ; LCIO ; Protozoa ; Colpoda cucullus ; Blepharisma undulans ; Oikomonas termo ; Pesticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A toxicity test using protozoa as test organisms was devised for pesticides. Two different methods were used, the most probable number method and the absorbance method (based on measurement of protozoa growth through absorbance). The ciliates Colpoda cucullus and Blepharisma undulans and the flagellate Oikomonas termo were isolated from different biological starter cultures and tested with the herbicides Chlorex, MCPA, dichlorprop and Matrigon, the fungicide Benlate, and the insecticide Sumicidin. The protozoans showed quite different sensitivities to the pesticides, using 9-h lethal concentrations (LC50 and LC10) as criteria. The 9-h LC50 (concentration at which 50% of the protozeon population has died after 9 h of incubation) ranged from 0.7 ppm for Benlate to 40000 ppm for Chlorex. The usual soil application rates of Chlorex, MCPA, and Benlate were toxic to some of the organisms.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Forest Ecology and Management 50 (1992), S. 299-316 
    ISSN: 0378-1127
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Clinica Chimica Acta 30 (1970), S. 129-136 
    ISSN: 0009-8981
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Nuclear Physics, Section A 149 (1970), S. 241-252 
    ISSN: 0375-9474
    Keywords: Nuclear reactions
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Analytica Chimica Acta 77 (1975), S. 293-297 
    ISSN: 0003-2670
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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