Controlled dephasing of a quantum dot in the Kondo regime

Kondo correlation in a spin polarized quantum dot (QD) results from the dynamical formation of a spin singlet between the dot's net spin and a Kondo cloud of electrons in the leads, leading to enhanced coherent transport through the QD. We demonstrate here significant dephasing of such transport by coupling the QD and its leads to potential fluctuations in a near by 'potential detector'. The qualitative dephasing is similar to that of a QD in the Coulomb Blockade regime in spite of the fact that the mechanism of transport is quite different. A much stronger than expected suppression of coherent transport is measured, suggesting that dephasing is induced mostly in the 'Kondo cloud' of electrons within the leads and not in the QD.Comment: to be published in PR

Personalized management of hypertensive patients: focus on prognostic biomarkers

Aim. To analyze level of circulating biomarkers of plasma vascular endothelial growth factor (VEGF) and tumor necrosis factor-α (TNF-α) during 3-month therapy with a fixed-dose combination of ramipril/indapamide (Konsilar-D24, AO Vertex, Russia), as well as to evaluate the antihypertensive efficacy of a fixed-dose combination of ramipril/indapamide (Konsilar-D24, JSC “Vertex”, Russia) in hypertensive (HTN) patients with type 2 diabetes (T2D).Material and methods. This prospective open-label study included 44 patients (aged 35 to 60 years) of both sexes with essential grade 1-2 HTN and concomitant compensated T2D, who did not reach the target blood pressure (BP) level using single or dual antihypertensive therapy, as well as patients who did not take antihypertensives. All patients included in the study initially underwent a set of standard clinical, laboratory and functional examinations in accordance with the clinical guidelines for the management of patients with HTN and T2D, as well as an assessment of the level of C-reactive protein, VEGF and TNF-α. Patients were monitored and treated with Konsilar-D24 for 3 months.Results. In 93,2% of patients, individual target BP values were achieved during the first 2-4 weeks of therapy with a fixed combination of ramipril/indapamide (Konsilar-D24). In the subsequent 3-month follow-up, the average daily BP level in all patients ranged from 129/79 mm Hg to 110/70 mm Hg. Three-month Konsilar-D24 therapy showed a decrease in microalbuminuria: the median values of microalbuminuria decreased by 2 times, and the decrease in the maximum recorded values reached 40% of the baseline. Decrease in mean TNF-α values after 3-month therapy with Konsilar-D24 was 33% of the baseline values, while the maximum recorded values during the specified period decreased by 17%. Decrease in median VEGF values after 3-month Konsilar-D24 therapy was 28%, while the maximum value decreased by 7%, the minimum — by 8%.Conclusion. Konsilar-D24 improves the prognosis in hypertensive patients not only by reducing BP to target values, but also by reducing the level of VEGF and TNF-α biomarkers that determine the progression of endothelial dysfunction, diabetic retinopathy, and microalbuminuria

Fano Effect in a Few-Electron Quantum Dot

We have studied the Fano effect in a few-electron quantum dot side-coupled to a quantum wire. The conductance of the wire, which shows an ordinal staircase-like quantization without the dot, is modified through the interference (the Fano effect) and the charging effects. These effects are utilized to verify the exhaustion of electrons in the dot. The "addition energy spectrum" of the dot shows a shell structure, indicating that the electron confinement potential is fairly circular. A rapid sign inversion of the Fano parameter on the first conductance plateau with the change of the wire gate voltage has been observed, and explained by introducing a finite width of dot-wire coupling.Comment: 11 pages, 7 figure

Features of the functional activity of macrophage link of immunity with gastroesophageal reflux disease depending on the type of reluctate: in vitro model

Aim. A generalized analysis of changes in functional activity of macrophages on the basis of phagocytic activity, cytokine profile, changes in the level of expression of surface markers characteristic of pro - or anti-inflammatory phenotype of the cells when exposed to reluctate. Materials and methods. Developed in vitro model of co-peritoneal macrophages of mice With57/BL6 (n=65) and reluctate patients with gastroesophageal reflux disease (GERD; n=65) having different pH values (three group comparison). Took into account the standard criteria phagocytic ability (absorption Staphylococcus aureus 9198, light microscopy), secretory activity (cytokine profile Th1/Th2, flow cytometry) and receptor characterization of macrophages (expression of CD25/80/163/206, flow cytometry). Results. The phagocytic activity of macrophages, calculated on the basis of the average number of bacteria ingested by one phagocyte, is not associated with the pH value of the added reluctate. It is established that the alkalinisation of reluctate leads to significant alteration in the expression of CD receptors - decrease M1 and increase M2. The index of total production of Th1/Тһ2 in groups progressively decreased with increasing pH of reluctate and amounted to 3.6 units in the group pH from 4.6 to 6.6; 2.8 units group a pH of 6.7-7.2 and 1.6 units in the group pH of 7.3 to 8.1, due to increased production of Th2 cytokines at offset reluctate pH to slightly alkaline side. The data obtained indicate the increase of expression and secretion of anti-inflammatory markers at an alkaline pH shift of reluctate. Analysis of the studied characteristics of the activity profile of macrophages in the proposed in vitro model justifies the need for considering the peculiarities of the functional activity of macrophages under the influence of reluctate different nature. The special importance of studying the cytokine profile and characteristics of the functional activity of macrophages in patients with GERD, given the nature of reluctate

Crossover from mesoscopic to universal phase for electron transmission in quantum dots

Measuring phase in coherent electron systems (mesoscopic systems) provides ample information not easily revealed by conductance measurements. Phase measurements in relatively large quantum dots (QDs) recently demonstrated a universal like phase evolution independent of dot size, shape, and occupancy. Explicitly, in Coulomb blockaded QDs the transmission phase increased monotonically by pi throughout each conductance peak, thereafter, in the conductance valleys the phase returned sharply to its base value. Expected mesoscopic features in the phase, related to spin degeneracy or to exchange effects, were never observed. Presently, there is no satisfactory full explanation for the observed phase universality. Unfortunately, the phase in a few-electron QDs, where it can be better understood was never measured. Here we report on such measurements on a small QD that occupy only 1-20 electrons. Such dot was embedded in one arm of a two path electron interferometer, with an electron counter near the dot. Unlike the repetitive behavior found in larger dots we found now mesoscopic features for dot occupation of less than some 10 electrons. An unexpected feature in this regime is a clear observation of the occupation of two different orbital states by the first two electrons - contrary to the recent publications. As the occupation increased the phase evolved and turned universal like for some 14 electrons and higher. The present measurements allowed us to determine level occupancy and parity. More importantly, they suggest that QDs go through a phase transition, from mesoscopic to universal like behavior, as the occupancy increases. These measurements help in singling out potential few theoretical models among the many proposed.Comment: 12 pages, 6 figure

Food effects on statolith composition of the common cuttlefish (Sepia officinalis)

The concentration of trace elements within cephalopod statoliths can provide a record of the environmental characteristics at the time of calcification. To reconstruct accurately the environmental characteristics at the time of calcification, it is important to understand the influence of as many factors as possible. To test the hypothesis that the elemental composition of cuttlefish statoliths could be influenced by diet, juvenile Sepia officinalis were fed either shrimp Crangon sp. or fish Clupea harengus under equal temperature and salinity regimes in laboratory experiments. Element concentrations in different regions of the statoliths (core–lateral dome–rostrum) were determined using laser ablation inductively coupled plasma mass spectrometry (LA- ICPMS). The ratios of Sr/Ca, Ba/Ca, Mn/Ca and Y/Ca in the statolith’s lateral dome of shrimp-fed cuttlefish were significantly higher than in the statolith’s lateral dome of fish-fed cuttlefish. Moreover, significant differences between statolith regions were found for all analysed elements. The fact that diet adds a considerable variation especially to Sr/Ca and Ba/Ca must be taken into account in future micro-chemical statolith studies targeting cephalopod’s life history

Tuning of the transverse magneto-optical Kerr effect in magneto-plasmonic crystals

The spectral properties of the transverse magneto-optical Kerr effect (TMOKE) in periodic metal–dielectric hybrid structures are studied, in particular with respect to the achievable magnitude. It is shown that the TMOKE is sensitive to the magneto-optical activity of the bismuth-substituted rare-earth iron garnet, which is used as a dielectric material in the investigated structures. For samples with larger Bi substitution level and, consequently, larger gyration constant, the magnitude of the TMOKE increases and reaches 13% in the case of a Bi1.8Lu1.2Fe3.6Al1.4O12 magnetic film. Further, it is demonstrated that the TMOKE vanishes at the high-symmetry points of the Brillouin zone (at the Γ and X points). The main enhancement of the TMOKE takes place near the resonances of the surface plasmon polaritons (SPPs) at the metal/magnetic–dielectric interface. However, near the degenerate resonances of the SPPs at the air/metal and metal/magnetic–dielectric interfaces the TMOKE is increased by the air/metal SPPs as well. This phenomenon is explained in terms of a coupled oscillator model

Magnetophotonic intensity effects in hybrid metal-dielectric structures

The magneto-optical properties of a hybrid metal-dielectric structure consisting of a one-dimensional gold grating on top of a magnetic waveguide layer are studied experimentally and theoretically. It is demonstrated that a magnetic field applied in the longitudinal configuration (in the plane of the magnetic film and perpendicular to the slits in the gold grating) to the metal-dielectric structure modifies the field distribution of the optical modes and thus changes the mode excitation conditions. In the optical far field, this manifests in the alteration of the optical transmittance or reflectance when the structure becomes magnetized. This magneto-optical effect is shown to represent a novel class of effects related to the magnetic-field-induced modification of the Bloch modes of the periodic hybrid structure. That is why we define this effect as longitudinal magnetophotonic intensity effect (LMPIE). The LMPIE has two contributions, odd and even in magnetization. While the even LMPIE is maximal for the light polarized perpendicular to the grating slits (TM) and minimal for the orthogonal polarization (TE), the odd LMPIE takes maximum values at some intermediate polarization and vanishes for pure TM and TE polarizations. Two principal modes of the magnetic layer - TM and TE - acquire in the longitudinal magnetic field additional field components and thus turn into quasi-TM and quasi-TE modes, respectively. The largest LMPIE is observed for excitation of the antisymmetrical quasi-TE mode by TM-polarized light. The value of the LMPIE measured for the plasmonic structure with a magnetic film of Bi2Dy1Fe4Ga1O12 composition is about 1% for the even effect and 2% for the odd one. However, the plasmonic structure with a magnetic film with a higher concentration of bismuth (Bi2.97Er0.03Fe4Al0.5Ga0.5O12) gives significantly larger LMPIE: even LMPIE reaches 24% and odd LMPIE is 9%. Enhancement of the magneto-optical figure of merit (defined as the ratio of the specific Faraday angle of a magnetic film to its absorption coefficient) of the magnetic films potentially causes the even LMPIE to exceed 100% as is predicted by calculations. Thus, the nanostructured material described here may be considered as an ultrafast magnetophotonic light valve