The concentration of abscisic acid in plants is regulated not only by biosynthesis, but also by metabolism. Abscisic acid is metabolized to phaseic acid via 8'-hydroxyabscisic acid, and phaseic acid is then converted to dihydrophaseic acid and its epimer. A quantitative analysis of these metabolites is important as well as that of abscisic acid to understand changes in the concentration of absc...

Understanding deuterium fractionation is currently one of the greatest challenges in astrochemistry. In this contribution deuteration experiments of the series CHn , n = 2–5, in a low temperature 22-pole ion trap are used to systematically test a simple chemical rule predicting which molecular ion undergoes deuterium exchange in collisions with HD. CH+4 turns out to be a problem case, where pre...

Incorporation of deuterium to passivate silicon-dangling bonds at the Si-SiO2 interface through ion implantation before the growth of the gate oxide is the focus of this work. Polycrystalline silicon gate n-channel metal-oxide-semiconductor diodes with 4 nm gate oxide grown on deuterium-implanted p-type silicon ^100& substrate were investigated. Deuterium implanted at a light dose of 1 3 10/cm ...

We report measurements of double radiative capture in pionic hydrogen and pionic deuterium. The measurements were performed with the RMC spectrometer at the TRIUMF cyclotron by recording photon pairs from pion stops in liquid hydrogen and deuterium targets. We obtained absolute branching ratios of (3.02 ± 0.27(stat.) ± 0.31(syst.)) × 10 for hydrogen and (1.42 ± 0.12 (stat.) ± 0.11(syst.)) × 10 ...

Detections of deuterium in high redshift Lyman limit absorption systems along the line of sight to QSOs promise to reveal the primordial deuterium abundance. At present, the deuterium abundances (D/H) derived from the very few systems observed are significantly discordant. Assuming the validity of all the data, if this discordance does not reflect intrinsic primordial inhomogeneity, then it mus...

A combination of hexamethyldisilane and deuterium oxide was found to work as a deuterium transfer reagent for alkynes in the presence of a catalytic amount of a palladium complex to give (E)-1,2-dideuterioalkenes selectively through the corresponding (Z)-isomer.

Recent confrontations of the predictions of standard big bang nucleosynthesis (SBBN) with the primordial abundances of the light nuclides inferred from observational data reveal a conflict. Simply put, compared to theoretical expectations the inferred primordial abundances of either deuterium or helium-4 (or both) are “too small”. Here I outline the “tension” between D and He in the context of ...

We discuss how measurements of fluctuations in the absorption of cosmic microwave background photons by neutral gas at redshifts z approximately 7-200 could reveal the primordial deuterium abundance of the Universe. The strength of the cross-correlation of brightness-temperature fluctuations in the redshifted 21-cm line of hydrogen with those in the redshifted 92-cm line of deuterium is proport...

It is argued that photochemical processes, driven by ultraviolet starlight, could lead to large deuterium fractionation for H2O and CH4 relative to H2 in the primitive solar nebula. Implications for deuterium enrichment observed in planetary atmospheres are briefly discussed.