Optical control of electron spin coherence in CdTe/(Cd,Mg)Te quantum wells

Optical control of the spin coherence of quantum well electrons by short laser pulses with circular or linear polarization is studied experimentally and theoretically. For that purpose the coherent electron spin dynamics in a n-doped CdTe/(Cd,Mg)Te quantum well structure was measured by time-resolved pump-probe Kerr rotation, using resonant excitation of the negatively charged exciton (trion) state. The amplitude and phase shifts of the electron spin beat signal in an external magnetic field, that are induced by laser control pulses, depend on the pump-control delay and polarization of the control relative to the pump pulse. Additive and non-additive contributions to pump-induced signal due to the control are isolated experimentally. These contributions can be well described in the framework of a two-level model for the optical excitation of the resident electron to the trion.Comment: 15 pages, 18 figure

Degrees of categoricity of computable structures

Defining the degree of categoricity of a computable structure M to be the least degree d for which M is d-computably categorical, we investigate which Turing degrees can be realized as degrees of categoricity. We show that for all n, degrees d. c. e. in and above 0(n) can be so realized, as can the degree 0(ω). © 2009 Springer-Verlag

Categoricity Spectra for Rigid Structures

© 2016 by University of Notre Dame. For a computable structure M, the categoricity spectrum is the set of all Turing degrees capable of computing isomorphisms among arbitrary computable copies of M. If the spectrum has a least degree, this degree is called the degree of categoricity of M. In this paper we investigate spectra of categoricity for computable rigid structures. In particular, we give examples of rigid structures without degrees of categoricity

Spin dynamics of electrons and holes in InGaAs/GaAs quantum wells at milliKelvin temperatures

The carrier spin dynamics in a n-doped (In,Ga)As/GaAs quantum well has been studied by time-resolved Faraday rotation and ellipticity techniques in the temperature range down to 430 milliKelvin. These techniques give data with very different spectral dependencies, from which nonetheless consistent information on the spin dynamics can be obtained, in agreement with theoretical predictions. The mechanisms of long-lived spin coherence generation are discussed for the cases of trion and exciton resonant excitation. We demonstrate that carrier localization leads to a saturation of spin relaxation times at 45 ns for electrons below 4.5 K and at 2 ns for holes below 2.3 K. The underlying spin relaxation mechanisms are discussed.Comment: 8 pages, 8 figure

Coherent spin relaxation in molecular magnets

Numerical modelling of coherent spin relaxation in nanomagnets, formed by magnetic molecules of high spins, is accomplished. Such a coherent spin dynamics can be realized in the presence of a resonant electric circuit coupled to the magnet. Computer simulations for a system of a large number of interacting spins is an efficient tool for studying the microscopic properties of such systems. Coherent spin relaxation is an ultrafast process, with the relaxation time that can be an order shorter than the transverse spin dephasing time. The influence of different system parameters on the relaxation process is analysed. The role of the sample geometry on the spin relaxation is investigated.Comment: Latex file, 22 pages, 7 figure

EVALUATION OF FCR THERAPY EFFICACY IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA BASED ON IMMUNOGENETIC CRITERIA

A number of studies have shown that distinct common variants of the genes controlling immune/inflammatory response may affect efficiency of chronic lymphocytic leukemia (CLL) treatment. In a recently published paper, we reported polymorphic variants of some immune response genes in CLL patients to be associated with different rates of disease progression. Correlations between the distribution of gene modification profiles in indolent and agressive forms of CLL have been established. The present study describes results of pharmacogenetic studies aimed for identifying associations between the immune response genes polymorphism, and efficacy of FCR treatment regimen in CLL patients. 19 polymorphic loci of 14 immune response genes were studied in 33 patients with CLL who received FCR therapy. The TLR2, TLR3, TLR4, TLR6, TLR9, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-17A, CD14, TNFα, FCGR2A genotypes were determined by polymerase chain reaction with allele-specific primers. CLL patients were divided into several groups depending on the terms of response to FCR treatment, i.e., achieving partial/complete remission after two, four, six courses of treatment, and those who did not respond to the therapy. Statistically significant differences in the distribution of haplotype frequencies were detected for the following genes: IL-1β (C-3953T, p = 0.02-0.009); IL-10 (C-819T, p = 0.04); IL-10 (G-1082A, p = 0.04-0.002-0.006), FCGR2A (His166Arg, p = 0.006); TLR4 (Thr399Ile, p = 0.02); TLR6 (Ser249Pro, p = 0.04); TLR9 (A2848G, p = 0.04-0.007); CD14 (C-159T, p = 0.03). When testing the significance hypothesis by multiple comparisons, the difference for the detected events was confirmed only for IL-10 gene (G-1082A, p < 0.01; χ2 = 20,082). The results show a relationship between the allelic status of the IL-10-1082 gene and the timing of response to FCR therapy, as well as predict a group of patients with primary-resistant CLL before treatment. The role of the relationship between IL-10 gene polymorphism and IL-10 production is discussed in connection with occurrence risk and clinical course of mature B-cell lymphoid malignancies. IL-10 is thought to be a growth factor for normal and transformed human B-lymphocytes, it controls a balance between cellular and humoral immune responses while exerting a pronounced immunosuppressive activity, along with ability to stimulate tumor cell proliferation. A rationale for conducting pharmacogenomic studies in CLL is provided, in order to predict efficiency of a specific drug or their combination in a distinct patient, thus representing chances to detect a factor which may influence success of the therapy since its earlier stage

Synthesis and cyclization of 1,5-bis((dimethyl(oxo)-Λ 6 - sulfanilidene)amino)-9,10- anthraquinone

In this article discusses some chemical properties of 1,5- bis((dimethyl(oxo)-λ 6 -sulfaniliden)amino)-9,10-anthroquinone.В данной статье рассмотрены некоторые химические свойства 1,5-бис((диметил(оксо)-λ 6 -сульфанилиден)амино)-9,10-антрахинона