Quantum diffusion of positive muons

Karlsson, E.

doi:10.1007/bf02150182

Cited by 5 publications

(3 citation statements)

References 18 publications

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“…CoQ 10 is known to be an unspecific antioxidant [45,46] and has an intrinsic role in mitochondrial electron transfer and energy metabolism [15,47]. No information on the effect of CoQ 10 on inducing the activity of the hepatic enzyme system has been documented as yet.…”

Section: Discussionmentioning

confidence: 99%

Effect of Coenzyme Q10 on Warfarin Hydroxylation in Rat and Human Liver Microsomes

Zhou¹,

Zhou²,

Chan

2005

CDM

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Our previous animal study has suggested that the accelerated metabolism of warfarin enantiomers with concurrent coenzyme Q(10) (CoQ(10)) treatment accounts for the reduced anticoagulant effect of warfarin in rats. The present study was to assess the effect of CoQ(310) on individual hydroxylation pathways of the in vitro microsomal metabolism of warfarin enantiomers and to extrapolate in vitro data to in vivo situation. The effect of the antioxidant CoQ(10) on the hydroxylation of warfarin enantiomers was examined using rat and human liver microsomes. Based on the in vitro kinetic data, together with the information retrieved from the literature, the magnitude of warfarin-CoQ(10) interaction in man was quantitatively predicted. In rat liver microsomes, CoQ(10) exhibited a selective activation effect on the 4'-hydroxylation of S-warfarin, with a K(A) value (i.e. dissociation constant of the enzyme-activator complex) being one third and one fifth of those for the 6- and 7-hydroxylation, respectively. The activation effect of CoQ(10) was selective towards the 6- and 7-hydroxylation of R-warfarin at low substrate concentrations, but towards the 4'-hydoxylation of the R-enantiomer at high substrate concentrations. In human liver microsomes, CoQ(10) was a selective activator of the 7-hydroxylation of both R- and S-enantiomers of warfarin, with K(A) values being half to one twelfth of those for the other pathways. A relatively accurate prediction was made for the increase in the total and hepatic clearance of both S- and R-warfarin in rats with concurrent CoQ(10) treatment based on their respective overall hydroxylation, when the active transport of CoQ(10)into the hepatocytes was taken into consideration. In man, one would expect about 32% and 17% increase in the total clearance of S- and R-warfarin, respectively, with coadministration of 100 mg CoQ(10). In both species, CoQ(10) had enzyme activation effect, which appeared to be regioselective but not stereoselective, on the formation of the phenolic metabolites of warfarin enantiomers. A moderate increase in the total clearance of warfarin enantiomers could occur with coadministration of CoQ(10)in humans.

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Section: Discussionmentioning

confidence: 99%

Effect of Coenzyme Q10 on Warfarin Hydroxylation in Rat and Human Liver Microsomes

Zhou¹,

Zhou²,

Chan

2005

CDM

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“…In well conducting materials the muons come to rest, with their full spin polarization intact, at an interstitial lattice site in about 1 ps which can be taken as 'momentary' when compared with the muon mean life of 2.2 µs. Being a light particle, the muon can diffuse through the lattice by thermal excitation and by tunneling processes [15,16]. Muon diffusion in pure Cu and in Cu doped with impurities in the 10-100 ppm range has been studied extensively [17,18].…”

Section: The µSr Methodsmentioning

confidence: 99%

Double-pass superluminescent multilayer quantum-well (GaAl)As heterostructure diodes with a reduced power consumption

Mamedov¹,

Маrmalyuk

Nikitin

et al. 2004

Quantum Electron.

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Samples of Co x Cu 1−x (x = 0.05, 0.02 and 0.01) produced by melt spinning and subsequent annealing were studied by muon spin rotation/relaxation (µSR ) spectroscopy with the aim to gain information on the dependence of the local magnetic properties like the magnitude, the distribution and the temporal behavior of the magnetic field at the muon site as function of Co concentration. In addition, we investigated for Co 0.02 Cu 0.98 the changes in µSR response as function of annealing times and temperatures. In all alloys, a spin-glass-like magnetic cluster state was seen well below the susceptibility cusp temperature. Above this temperature, cluster spin dynamics sets in but with low fluctuation rates even at high temperatures reflecting the presence of strong cluster-cluster couplings. A free paramagnetic cluster state is not formed. Spin dynamic properties are different for the x = 0.05 and 0.02 compounds and the x = 0.01 alloy. In the former compounds, the coexistence of a slower and a faster fluctuating fraction is found, arising from a non-uniform cluster size distribution or a non-random spatial distribution of clusters. In the latter compound, the spin dynamical state is homogeneous, but shows an unusual µSR response requiring the presence of simultaneous fluctuations in spin orientation and moment magnitude. It further points to the presence of a partial loss of magnetic clusters. The variation of annealing times and temperatures for Co 0.02 Cu 0.98 influences details of µSR spectral parameters but leaves the overall response the same.

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“…In this case, the periodic potential barrier of the crystal traps the muons in fixed sites defined by the spatial symmetry. But muon diffusion is still possible if the transitions between sites are due to quantum mechanical tunneling [47,48]. Conduction electrons in a metal act to screen the muons, so a combination of the bare muon and screening charge must be considered when modeling the diffusion.…”

Section: Introductionmentioning

confidence: 99%

Quantum muon diffusion and the preservation of time-reversal symmetry in the superconducting state of type-I rhenium

et al. 2022

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Elemental rhenium exhibiting type-II superconductivity has been previously reported to break time-reversal symmetry in the superconducting state. We have investigated an arc-melted sample of rhenium exhibiting type-I superconductivity. Low-temperature zero-field muon-spin relaxation measurements indicate that time-reversal symmetry is preserved in the superconducting state. Muon diffusion is observed, which is due to quantum mechanical tunneling between interstitial sites. The normal state behavior is characterized by the conduction electrons screening the muons and thermal broadening, and is typical for a metal. Energy asymmetries between muon trapping sites and the superconducting energy gap also characterize the superconducting state behavior.

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Quantum diffusion of positive muons

Cited by 5 publications

References 18 publications

Effect of Coenzyme Q10 on Warfarin Hydroxylation in Rat and Human Liver Microsomes

Effect of Coenzyme Q10 on Warfarin Hydroxylation in Rat and Human Liver Microsomes

Double-pass superluminescent multilayer quantum-well (GaAl)As heterostructure diodes with a reduced power consumption

Quantum muon diffusion and the preservation of time-reversal symmetry in the superconducting state of type-I rhenium

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