University of Basel

About: University of Basel is a education organization based out in Basel, Basel-Stadt, Switzerland. It is known for research contribution in the topics: Population & Gene. The organization has 25084 authors who have published 52975 publications receiving 2388002 citations. The organization is also known as: Universität Basel & Basel University.

Phonon-Induced Decay of the Electron Spin in Quantum Dots

Abstract: We study spin relaxation and decoherence in a GaAs quantum dot due to spin-orbit (SO) interaction. We derive an effective Hamiltonian which couples the electron spin to phonons or any other fluctuation of the dot potential. We show that the spin decoherence time ${T}_{2}$ is as large as the spin relaxation time ${T}_{1}$, under realistic conditions. For the Dresselhaus and Rashba SO couplings, we find that, in leading order, the effective $B$ field can have only fluctuations transverse to the applied $B$ field. As a result, ${T}_{2}=2{T}_{1}$ for arbitrarily large Zeeman splittings, in contrast to the naively expected case ${T}_{2}\ensuremath{\ll}{T}_{1}$. We show that the spin decay is drastically suppressed for certain $B$-field directions and ratios of SO coupling constants. Finally, for the spin-phonon coupling, we show that ${T}_{2}=2{T}_{1}$ for all SO mechanisms in leading order in the electron-phonon interaction.

Nitrogen and oxygen isotope fractionation during dissimilatory nitrate reduction by denitrifying bacteria

Abstract: We report the first measurements of coupled nitrogen (N) and oxygen (O) isotope fractionation of nitrate by laboratory cultures of denitrifying bacteria Two seawater strains (Pseudomonas stutzeri, Ochrobactrum sp) and three freshwater strains (Paracoccus denitrificans, Pseudomonas chlororaphis, Rhodobacter sphaeroides) were examined Among four strains of facultative anaerobic denitrifiers, N and O isotope effects were variable, ranging from 5% to 25%, with evidence for a drop in the isotope effects as nitrate concentrations approached the halfsaturation constant for nitrate transport O isotope effects were similar to their corresponding N isotope effect, such that the progressive increase in nitrate d18O, when plotted against that in d15N (where d18Osample 5 [(18 O: 16O)sample/(18 O: 16O)reference 2 1] 3 1000, and d15Nsample 5 [(15 N: 14N)sample/(15 N: 14N)reference 2 1] 3 1000), yielded slopes of 086 to 102, with a mean value of 096 R sphaeroides, a photo-heterotroph that possesses only a periplasmic (nonrespiring) dissimilatory nitrate reductase, showed less variability in nitrate N isotope effects, between 13% and 20%, with a modal value of ,15% In contrast to the respiratory denitrifiers, R sphaeroides consistently showed a distinct ratio of d 18 Ot od 15 N change of ,062 We hypothesize that heavy N and O isotope discrimination during respiratory denitrification occurs during the intracellular reduction of nitrate by the respiratory nitrate reductase, and the observed magnitude of fractionation is likely regulated by the ratio of cellular nitrate efflux relative to uptake The data for R sphaeroides are consistent with isotope discrimination directly reflecting the N and O isotope effects of the periplasmic nitrate reductase NAP, without modification by nitrate uptake and efflux

An Enzyme-Linked Immunoassay for Nerve Growth Factor (NGF): A Tool for Studying Regulatory Mechanisms Involved in NGF Production in Brain and in Peripheral Tissues

Abstract: A sensitive enzyme-linked immunosorbent assay (ELISA) for nerve growth factor (NGF) has been developed. The sensitivity of this assay (0.1 pg/well) permits the quantification of endogenous immunoreactive NGF in the peripheral nervous system and the CNS. Studies on the regulatory mechanisms involved in NGF production indicate that, in addition to neurally mediated mechanisms, other stimuli, e.g., inflammation, significantly contribute to NGF production.

Pharmacogenetics: five decades of therapeutic lessons from genetic diversity

Abstract: Physicians have long been aware of the subtle differences in the responses of patients to medication. The recognition that a part of this variation is inherited, and therefore predictable, created the field of pharmacogenetics fifty years ago. Knowing the gene variants that cause differences among patients has the potential to allow 'personalized' drug therapy and to avoid therapeutic failure and serious side effects.