Simultaneous en-face imaging of two layers in the human retina by low-coherence reflectometry

We show that with a fiberized multiple Michelson-interferometer-type configuration, transverse images from several layers in the human eye can be simultaneously obtained. We demonstrate the principle by producing simultaneous 100x100 pixel en-face images of a 4 mmx4 mm region on a postmortem retina for two depth positions 250 mum apart.     

Distribution of pairing functions in superconducting spin valve SF1F2

The distribution of the spin-singlet component, the short-range spin-triplet component with zero projection, and the long-range spin-triplet component with projection ±1 of the superconducting pairing function has been obtained for different regimes of switching of a spin valve with a three-layer heterostructure (superconductor/ferromagnet/ferromagnet). The distribution of the components is discussed as the main reason for the behavior of the superconducting transition temperature as a function of the angle between the magnetic moments of the ferromagnetic layers in these regimes.     

Expression of ionotropic glutamate receptors in the retina of the rdta transgenic mouse

Background

One mechanism that directs the action of the second messengers, cAMP and diacylglycerol, is the compartmentalization of protein kinase A (PKA) and protein kinase C (PKC). A-kinase anchoring proteins (AKAPs) can recruit both enzymes to specific subcellular locations via interactions with the various isoforms of each family of kinases. We found previously that a new class of AKAPs, dual-specific AKAPs, denoted D-AKAP1 and D-AKAP2, bind to RIα in addition to the RII subunits.

Results

Immunohistochemistry and confocal microscopy were used here to determine that D-AKAP1 colocalizes with RIα at the postsynaptic membrane of the vertebrate neuromuscular junction (NMJ) and the adjacent muscle, but not in the presynaptic region. The labeling pattern for RIα and D-AKAP1 overlapped with mitochondrial staining in the muscle fibers, consistent with our previous work showing D-AKAP1 association with mitochondria in cultured cells. The immunoreactivity of D-AKAP2 was distinct from that of D-AKAP1. We also report here that even though the PKA type II subunits (RIIα and RIIβ) are localized at the NMJ, their patterns are distinctive and differ from the other R and D-AKAP patterns examined. PKCβ appeared to colocalize with the AKAP, gravin, at the postsynaptic membrane.

Conclusions

The kinases and AKAPs investigated have distinct patterns of colocalization, which suggest a complex arrangement of signaling micro-environments. Because the labeling patterns for RIα and D-AKAP 1 are similar in the muscle fibers and at the postsynaptic membrane, it may be that this AKAP anchors RIα in these regions. Likewise, gravin may be an anchor of PKCβ at the NMJ.     

Expression of ionotropic glutamate receptors in the retina of the rdta transgenic mouse

Background  

The expression of retinal CaMKII is up-regulated in the retina of the rdta mouse in which rod photoreceptors are genetically ablated. As ionotropic glutamate receptors are known substrates of CAMKII, this study set out to determine if the protein levels of ionotropic glutamate receptors in the rdta mouse retina are also affected.     

Production of nanocrystal layers in monocrystal silicon in the beam-type plasma of a high-voltage discharge

The results of investigations on the formation of nanostructured hydrogen–silicon complexes in the nearsurface layer of monocrystal silicon exposed to hydrogen-containing plasma are presented. By using infrared and Auger spectroscopy, it has been shown that the formation of nanolayers and, hence, an extreme change of the resistivity of the near-surface layer take place only at short treatment times.     

Ion acoustic double layers in the vicinity of the critical velocity in a weakly relativistic plasma

Ion acoustic double layers in the vicinity of the critical velocity in a weakly relativistic plasma are found for the first time from a mixed form of the KdV and mKdV equations by the reductive perturbation method. It is shown to yield compressive and rarefactive double-layer profiles under certain conditions.     

On the structure of the two-dimensional spatially periodic inner transition layers in a gas-discharge plasma

We investigate the structure of the spatially periodic inner boundary layers in the plasma of a positive glow-discharge column produced in a long cylindrical tube with an electropositive gas inside. Asymptotic methods, namely, the method of boundary functions, are used to analyze the initial mathematical model. We consider the formation of contrast burst-type structures. We have found all principal terms of the boundary-layer asymptotics of the solution. The results obtained are compared with the available probe measurements of basic physical parameters of ionization waves (strata) in neon at low pressures.     

The special features of the Hall effect in GaMnSb layers deposited from a laser plasma

Epitaxial GaMnSb films with Mn contents up to about 10 at. % were obtained by deposition from a laser plasma in vacuum. The growth temperature T _s during deposition was varied from 440 to 200°C, which changed the concentration of holes from 3 × 10¹⁹ to 5 × 10²⁰ cm^?3, respectively. Structure studies showed that, apart from Mn ions substituting Ga, the GaMnSb layers contained ferromagnetic clusters with Mn and shallow acceptor defects of the Ga_Sb type controlled by the T _s value. Unlike single-phase GaMnSb systems studied earlier with negative anomalous Hall effect values and Curie temperatures not exceeding 30 K, the films obtained in this work exhibited a positive anomalous Hall effect, whose hysteresis character manifested itself up to room temperature and was the more substantial the higher the concentration of holes. The unusual behavior of this effect was interpreted in terms of the interaction of charge carriers with ferromagnetic clusters, which was to a substantial extent determined by the presence of Schottky barriers at the boundary between the clusters and the semiconducting matrix; this interaction increased as the concentration of holes grew. The absence of this effect in semiconducting compounds based on III–V Group elements with MnSb or MnAs ferromagnetic clusters was discussed in the literature; we showed that this absence was most likely related to the low hole concentrations in these objects.     

Elastic and inelastic processes in the interaction of 1–10 eV ions with solids: ion transport through surface layers

We review the escape depth of secondary ions (or neutrals) desorbing from solid surfaces under the impact of electrons, photons or ions. We survey ion (or neutral) transport through many materials, but most are wide band gap insulators such as rare-gas solids and molecular solids. We address the issue of low-energy (<10 eV) ion—solid interactions, and review experimental and theoretical studies that provide insight into the physical mechanisms of these interactions, such as elastic scattering, charge transfer and ion—molecule reactions. Although it is usually assumed that most of the secondary ions stem from the top surface layer, we show that this is not necessarily the case: In certain instances, 1–10 eV ions are able to transmit solid films which are several monolayers thick. The transport of low-energy ions through materials has very broad implications. We point out the importance of these results for electron or photon stimulated desorption (ESD/PSD), secondary ion mass spectrometry (SIMS), and ion-sputtering of surfaces, and discuss their relevance to other fields, such as ion beam deposition (IBD), low-energy ion implantation, and electrochemistry.     

On existence of the spatial charge layers in plasma with regions of rapid growth of the ionization rate

1D quasi-static self-consistent model of nonequilibrium nitrogen and oxygen plasma with highly non-uniform spatial distribution of the electric field strength is used for analysis of the correlation of ionization rate profile and charged particles profiles. It is shown that inside a region of local increase of the ionization rate the layers with violation of quasi-neutrality can exist. This leads to the appearance of local static electric fields. Special attention is devoted to plasma resonance regions in microwave plasma. The role of negative ions is also studied.     

Distribution of plasma parameters in the cathode region of a glow discharge in nitrogen

The experiments with a low-pressure glow discharge in nitrogen indicate the formation of a potential well for thermal electrons and the sign reversal of the electric field near the concentration maximum of the near-cathode plasma. Depending on reduced discharge length pL, one or two field reversal points exist, which correlate with the sign of the anode fall (negative or positive, respectively).     

On the basic transcendental functions appearing in the dielectric tensor of a weakly relativistic Maxwellian plasma

Summary It is shown how to deduce in a straightforward way the class of transcendental functions which appear in the elements of the dielectric tensor of a weakly relativistic thermal plasma. The deduction is made directly from the second form of Trubnikov integrals and is valid for arbitrarily large values of the wave perpendicular refractive index.

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Riassunto Si mostra come sia possibile dedurre in modo molto diretto la famiglia di trascendenti che appare negli elementi della matrice dielettrica di un plasma debolmente relativistico in condizioni di equilibrio termico. Il procedimento parte direttamente dalla così detta seconda forma degli integrali di Trubnikov ed è valido per valori arbitrariamente grandi dell’indice di rifrazione perpendicolare al campo magnetico nel quale è immerso il plasma.

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Резюме Мы показываем, как вывести непосредственным образом класс трансцендентных функций, которые появляются в элементах диэлектрического тензора для слабо релятивистской плазмы в условиях теплового равновесия. Вывод проводится непосредственно из второй формы интегралов Трубникова и справедлив для произвольно больших величин показателя преломления для волны, перпендикулярной магнитному полю, в которое помещена плазма.

     

Localization of plasma layers in the ionosphere based on observing variations in the phase and amplitude of radiowaves along the satellite-to-satellite path

We propose a method for localization of layered structures in the ionosphere, which is based on simultaneous observations of time variations in the intensity and phase of radio waves along transionospheric paths. The method determines the position of the turning point, where the gradient of the refraction index is perpendicular to the ray trajectory and the influence of the layered structure on the parameters of radio waves is maximal. The layer position is estimated by analyzing the variations in the phase and intensity of radio waves in combination. The method was used to analyze the experimental data obtained by the radio occulation mission CHAMP. The position for inclined plasma layers was determined and the electron density distribution was found for the considered radio occultation sessions. The method was verified by measuring the turning point on the ray trajectory in a neutral gas in the atmosphere. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 1, pp. 1–9, January 2008.     

Features of electron distribution functions in a plasma in the presence of crossed electric and magnetic fields

We treat the formation features of distribution functions of magnetized electrons over velocities and energies in a plasma located in crossed electric and magnetic fields. It is shown that the variation of electron velocity and energy between collisions, related to the motion in external fields, can substantially affect the shape of the distribution function. It is established that for strong anisotropy of the velocity distribution and for electron scattering by slightly mobile heavy particles the electron distribution function over energy has two maxima. This given feature of the electron distribution is not related to the presence of two electron groups in the plasma, but is a consequence of the transformation of distribution functions in crossed electric and magnetic fields.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 88–94, August, 1991.The author is grateful to A. A. Titov for carrying out the numerical calculations, and to A. S. Dolgov for a number of useful comments.