Single spins in nanowire quantum dots with strong spin-orbit coupling

Quantum NanoscienceApplied Science

Limited evidence: higher efficacy of nasal saline irrigation over nasal saline spray in chronic rhinosinusitis: an update and reanalysis of the evidence base

OBJECTIVE: To assess the effectiveness of nasal saline irrigation in adult patients with chronic rhinosinusitis. DATA SOURCES: PubMed, EMBASE, the Cochrane Library. REVIEW METHODS: A comprehensive search was performed, and 2 authors independently screened publications. The design of selected studies was assessed on directness of evidence and risk of bias. RESULTS: Of 1596 publications, 1 open-label randomized trial with high directness of evidence and moderate risk of bias was included. In this study, 127 patients were randomly allocated to isotonic nasal saline irrigation or isotonic nasal saline spray, as added to their usual medication. The mean 20-Item Sinonasal Outcome Test (SNOT-20) scores of those treated with nasal irrigation improved more than those allocated to nasal spray. While the authors consider an improvement of 16 or more to be clinically meaningful, the changes from baseline in mean SNOT-20 scores of those treated with irrigation (and the differences with those treated with nasal spray) at 2, 4, and 8 weeks were 12.2 (difference 5.5, [95% confidence interval -0.04 to 11.0]), 16.2 (difference 8.8 [3.2 to 14.4]), and 15.0 (difference 6.5 [0.4 to 12.6]), respectively. Side effects of posttreatment nasal dripping were common but minor and did not lead to discontinuation of treatment. CONCLUSION AND RECOMMENDATION: It should be explained to adult patients with chronic rhinosinusitis that there is limited information on the relative effect of nasal saline irrigation and nasal saline spray on subjective symptom improvement, since there is only 1 trial available with a moderate risk of bias showing limited benefit of irrigation over spray

Exploring the conformational equilibrium of E. coli thioredoxin reductase: Characterization of two catalytically important states by ultrafast flavin fluorescence spectroscopy

The conformational dynamics of wild-type Escherichia coli thioredoxin reductase (TrxR) and the mutant enzyme C138S were studied by ultrafast time-resolved fluorescence of the flavin cofactor in combination with circular dichroism (both in the flavin fingerprint and far-UV regions) and steady-state fluorescence and absorption spectroscopy. The spectroscopic data show two conformational states of the enzyme (named FO and FR), of which the physical characteristics differ considerably. Ultrafast fluorescence lifetime measurements make it possible to distinguish between the two different populations: Dominant picosecond lifetimes of ∼1 ps (contribution 75%) and 7 ps (8%) are associated with the FO species in TrxR C138S. Long-lived fluorescence with two time constants in the range of 0.2–1 ns (total contribution 17%) originates from enzyme molecules in the FR conformation. The near absence of fast lifetime components in oxidized wild-type TrxR supports the idea of this enzyme being predominantly in the FR conformation. The emission spectrum of the FO conformation is blue-shifted with respect to that of the FR conformation. Because of the large difference in fluorescence characteristics, fluorescence measurements on time scales longer than 100 ps are fully determined by the fraction of enzyme molecules in the FR conformation. Binding of the thiol reagent phenyl mercuric acetate to wild-type enzyme and TrxR C138S stabilizes the enzymes in the FR conformation. Specific binding of the NADPH-analog, AADP+, to the FR conformation resulted in dynamic fluorescence quenching in support of the multiple quenching sites model. Raising the temperature from 277K–323K resulted in a moderate shift to the FR conformation for TrxR C138S. High concentrations of the cosolvent glycerol triggered the domain rotation from the FO to the FR conformation

Fast Spin-Orbit Qubit in an Indium Antimonide Nanowire

Because of the strong spin-orbit interaction in indium antimonide, orbital motion and spin are no longer separated. This enables fast manipulation of qubit states by means of microwave electric fields. We report Rabi oscillation frequencies exceeding 100 MHz for spin-orbit qubits in InSb nanowires. Individual qubits can be selectively addressed due to intrinsic differences in their g factors. Based on Ramsey fringe measurements, we extract a coherence time T2*=8±1??ns at a driving frequency of 18.65 GHz. Applying a Hahn echo sequence extends this coherence time to 34 ns.QN/Quantum NanoscienceElectrical Engineering, Mathematics and Computer Scienc

Entanglement of spin-orbit qubits induced by Coulomb interaction

Spin-orbit qubit (SOQ) is the dressed spin by the orbital degree of freedom through a strong spin-orbit coupling (SOC). We show that Coulomb interaction between two electrons in quantum dots located separately in two nanowires can efficiently induce quantum entanglement between two SOQs. But to achieve the highest possible value for two SOQs concurrence, strength of SOC and confining potential for the quantum dots should be tuned to an optimal ratio. The physical mechanism to achieve such quantum entanglement is based on the feasibility of the SOQ responding to the external electric field via an intrinsic electric dipole spin resonance