Results 51 to 60 of about 12,068,996 (359)

Shifts in rotifer life history in response to stable isotope enrichment: testing theories of isotope effects on organismal growth [PDF]

Royal Society Open Science, 2017
In ecology, stable isotope labelling is commonly used for tracing material transfer in trophic interactions, nutrient budgets and biogeochemical processes.
Elena Gorokhova
doaj   +1 more source

Isotope effect in the presence of a pseudogap [PDF]

Physical Review B, 2000
6 pages, 3 Postscript figures, submitted to Phys.
openaire   +3 more sources

Chlorine and Bromine Isotope Fractionation of Halogenated Organic Pollutants on Gas Chromatography Columns [PDF]

Journal of Chromatography A, 2017, 2017
Compound-specific chlorine/bromine isotope analysis (CSIA-Cl/Br) has become a useful approach for degradation pathway investigation and source appointment of halogenated organic pollutants (HOPs). CSIA-Cl/Br is usually conducted by gas chromatography-mass spectrometry (GC-MS), which could be negatively impacted by chlorine and bromine isotope ...
arxiv   +1 more source

Isotope Effects, Dynamic Matching, and Solvent Dynamics in a Wittig Reaction. Betaines as Bypassed Intermediates

Journal of the American Chemical Society, 2014
The mechanism of the Wittig reaction of anisaldehyde with a stabilized ylide was studied by a combination of 13C kinetic isotope effects, conventional calculations, and molecular dynamics calculations in a cluster of 53 THF molecules. The isotope effects
Zhuo Chen, Yexenia Nieves-Quinones, Jack R. Waas, D. A. Singleton   +3 more
semanticscholar   +1 more source

Nonequilibrium H/D isotope effects from trajectory-based nonadiabatic dynamics.

Journal of Physical Chemistry A, 2014
Ground-state equilibrium kinetic isotope effects can be treated well in the framework of transition state theory, whereas excited-state nonequilibrium isotope effects are theoretically less explored.
Lasse Spörkel, G. Cui, A. Koslowski, W. Thiel   +3 more
semanticscholar   +1 more source

The Saccharomyces cerevisiae amino acid transporter Lyp1 has a broad substrate spectrum

FEBS Letters, EarlyView.
In Saccharomyces cerevisiae, Yeast Amino acid Transporter family members mediate the import of amino acids, ranging from substrate specialists to generalists. Here, we show that the specialist transporter, Lyp1, has a broader substrate spectrum than previously described, with affinity constants spanning from micromolar to millimolar.
Foteini Karapanagioti, Sebastian Obermaier, Dirk J. Slotboom, Bert Poolman   +3 more
wiley   +1 more source

Light oxygen isotopic composition in deep mantle reveals oceanic crust subduction before 3.3 billion years ago

Communications Earth & Environment
Compositional heterogeneity exists in Earth’s deep mantle, which can be caused by the subduction of oceanic slabs. How early this process started on Earth remains highly debated due to the scarcity of early Archean materials with pristine mantle ...
Dongjian Ouyang, Huiming Bao, Gary R. Byerly, Qiuli Li   +3 more
doaj   +1 more source

Plasma lipidomic and metabolomic profiles in high‐grade glioma patients before and after 72‐h presurgery water‐only fasting

Molecular Oncology, EarlyView.
Presurgery 72‐h fasting in GB patients leads to adaptations of plasma lipids and polar metabolites. Fasting reduces lysophosphatidylcholines and increases free fatty acids, shifts triglycerides toward long‐chain TGs and increases branched‐chain amino acids, alpha aminobutyric acid, and uric acid.
Iris Divé, Lisa Hahnefeld, Katharina J. Wenger, Donat Kögel, Joachim Steinbach, Gerd Geisslinger, Michael W. Ronellenfitsch, Irmgard Tegeder   +7 more
wiley   +1 more source

The barite record of the past seawater oxygen isotope composition

Nature Communications
The oxygen isotope composition of seawater (δ18Oseawater) is shaped by high- and low-temperature rock-water interactions, reflecting Earth system’s dynamics and evolution.
Tao Han, Huiming Bao, Yongbo Peng, Zhitong Lu, Yunzhou Song   +4 more
doaj   +1 more source

Stable isotopes in caves over altitudinal gradients: fractionation behaviour and inferences for speleothem sensitivity to climate change [PDF]

Climate of the Past, 2013
The interpretation of stable isotope ratios in speleothem calcite is complex, and only in a few cases, unequivocal relationships with palaeoclimate parameters have been attained.
V. E. Johnston, A. Borsato, C. Spötl, S. Frisia, R. Miorandi   +4 more
doaj   +1 more source