a total of 40 samples from carbonates and 8 samples from silicate rocks were analyzed from the sangan iron skarn deposit to examine behavior of the oxygen and carbon isotopes. the higher values of ?18o are from metamorphic calcite and dolomite and lower ones are from granitic rocks. although the ?18o and ?13c values of calcite and dolomite in marble yield the highest values in the sangan deposi...

a total of 40 samples from carbonates and 8 samples from silicate rocks were analyzed from the sangan iron skarn deposit to examine behavior of the oxygen and carbon isotopes. the higher values of ?18o are from metamorphic calcite and dolomite and lower ones are from granitic rocks. although the ?18o and ?13c values of calcite and dolomite in marble yield the highest values in the sangan deposi...

A total of 40 samples from carbonates and 8 samples from silicate rocks were analyzed from the Sangan iron skarn deposit to examine behavior of the oxygen and carbon isotopes. The higher values of ?18O are from metamorphic calcite and dolomite and lower ones are from granitic rocks. Although the ?18O and ?13C values of calcite and dolomite in marble yield the highest values in the Sangan deposi...

Silvicultural thinning usually improves the water status of remaining trees in water-limited forests. We evaluated the usefulness of a dual stable isotope approach (d 13C, d 18O) for comparing the physiological performance of remaining trees between forest stands subjected to two different thinning intensities (moderate versus heavy) in a 60-yearold Pinus halepensis Mill. plantation in semiarid...

The nitrosative deaminations (37 degrees C, NaNO2, NaAc buffer, pH 3.7) of guanosine 1r in (18O)water (97.6%) and of [6-18O]-1r in normal water were studied. [6-(18)O]-1r was prepared from 2-amino-6-chloropurine riboside using adenosine deaminase. The reaction products xanthosine 3r and oxanosine 4r were separated by HPLC and characterized by LC/MS analysis and 13C NMR spectroscopy. The 18O-iso...

Stable oxygen and carbon isotope ratios ( 18O and 13C) from archived otoliths of Pacific halibut, Hippoglossus stenolepis, were measured to examine the most recent regime shifts in British Columbia and the Gulf of Alaska. 18O values of these otoliths ranged from −1.5 to +2.8‰ VPDB, and were consistent with the life stages and migration behavior of halibut. 13C varied from −3.3 to +0.9‰ VPDB, bu...

Large-bodied, semiaquatic herbivorous mammals have been a recurring component of most continental ecosystems throughout the Cenozoic. Identification of these species in the fossil record has largely been based on the morphological similarities with present-day hippopotamids, leading to the designation of this pairing of body type and ecological niche as the hippo ecomorph. These morphological c...

A stable mu-nitrido diiron phthalocyanine activates H2O2 to oxidize CH4 in water at 25-60 degrees C to methanol, formaldehyde and formic acid as evidenced using 13C and 18O labelling.

Irradiation of a Ne matrix sample containing NO and CO near 4 K with an ArF excimer laser at 193 nm yielded new lines at 2045.1 and 968.0 cm(-1) that were depleted upon secondary photolysis at 308 nm. These lines are assigned to C=O stretching and mixed stretching modes of ONCO, based on results of 15N-, 13C-, and 18O-isotopic experiments and quantum-chemical calculations. These calculations us...

Experiments with cerulenin-inhibited cultures of S. violaceoruber showed conversion of dihydrogranaticin (II) into granaticin (I), but not vice versa, confirming an earlier conclusion that II is the biosynthetic precursor of I. Feeding of CH3(13)C18O2Na followed by 13C-NMR analysis of the product by the 18O shift method indicated the expected incorporation of 18O at carbons 1, 11 and 13 of I an...