Advances of Squamata astroglia to other reptiles : numerous astrocytes and glial fibrillary acidic protein (GFAP)-free areas : a preliminary study

Squamata are diapsid reptiles. Testudines were positioned formerly to the most ancient group, Anapsida, but recently they are also classified as diapsid reptiles, although their position within this group is uncertain. The investigated species of this study involved lizards (Timon tanginatus, Lacertidae; Pogona vitticeps, Agamidae; Eublepharis macularis, Gekkota; Chameleo calypratus, Chameleonidae), snakes (Epicrates cenchria maurus, Boidae; Python regius, Pythonidae; Pantherophis guttata and P. obsoletus quadrivittatus, Colubridae), and turtles (Testudo hermanni, Testudinidae; Trachemys scripta and Mauremyssinensis, Emydidae; Pelomedusa subrufa, Pleurodira). They were overanasthetised with Nembutal and transcardially perfused with 4% buffered paraformaldehyde. Coronal sections were processed according to the immunoperoxidase protocol. Monoclonal anti-GFAP and other glial markers were used. The main astroglia were the radial ependymoglia. There were two principal advances in Squamata. First, astrocytes were frequent in several areas, although, nowhere predominated. Furthermore, considerable GFAP-poor areas were found. They were extended in Python, and in Pogona and Chamaeleo GFAP was almost missing throughout the brain. The Squamata share more common astroglial features with birds than the turtles, although, represents a separate branch (Lepidosauria versus Archosauria). In mammals and birds the GFAP-free areas are usually advanced, expanded and plastic ones. Note that Squamata display quite complex behavioural phenomena related to other reptiles

Quantum rings with time dependent spin-orbit coupling: Rabi oscillations, spintronic Schrodinger-cat states, and conductance properties

The strength of the (Rashba-type) spin-orbit coupling in mesoscopic semiconductor rings can be tuned with external gate voltages. Here we consider the case of a periodically changing spin-orbit interaction strength as induced by sinusoidal voltages. In a closed one dimensional quantum ring with weak spin-orbit coupling, Rabi oscillations are shown to appear. We find that the time evolution of initially localized wave packets exhibits a series of collapse and revival phenomena. Partial revivals -- that are typical in nonlinear systems -- are shown to correspond to superpositions of states localized at different spatial positions along the ring. These "spintronic Schrodinger-cat sates" appear periodically, and similarly to their counterparts in other physical systems, they are found to be sensitive to environment induced disturbances. The time dependent spin transport problem, when leads are attached to the ring, is also solved. We show that the "sideband currents" induced by the oscillating spin-orbit interaction strength can become the dominant output channel, even in the presence of moderate thermal fluctuations and random scattering events.Comment: 11 pages, 9 figures, submitted to PR

Magnetoconductance properties of rectangular arrays of spintronic quantum rings

Electron transport through multi-terminal rectangular arrays of quantum rings is studied in the presence of Rashba-type spin-orbit interaction (SOI) and of a perpendicular magnetic field. Using the analytic expressions for the transmission and reflection coefficients for single rings we obtain the conductance through such arrays as a function of the SOI strength, the magnetic flux, and of the wave vector $k$ of the incident electron. Due to destructive or constructive spin interferences caused by the SOI, the array can be totally opaque for certain ranges of $k$, while there are parameter values where it is completely transparent. Spin resolved transmission probabilities show nontrivial spin transformations at the outputs of the arrays. When point-like random scattering centers are placed between the rings, the Aharonov-Bohm peaks split, and an oscillatory behavior of the conductance emerges as a function of the SOI strength.Comment: 10 pages, 10 figures, submitted to PR

Leptonic decay-constant ratio fK/fπf_K/f_\pi from lattice QCD using 2+1 clover-improved fermion flavors with 2-HEX smearing

We present a calculation of the leptonic decay-constant ratio $f_K/f_\pi$ in 2+1 flavor QCD. Our data set includes five lattice spacings and pion masses reaching down below the physical one. Special emphasis is placed on a careful study of all systematic uncertainties, especially the continuum extrapolation. Our result is perfectly compatible with the first-row unitarity constraint of the Standard Model.Comment: 19 pages, 6 figures, 3 tables; v2: added supplementary analysis, version published in Phys. Rev.

PARP-Inhibitor Treatment Prevents Hypertension Induced Cardiac Remodeling by Favorable Modulation of Heat Shock Proteins, Akt-1/GSK-3beta and Several PKC Isoforms.

Spontaneously hypertensive rat (SHR) is a suitable model for studies of the complications of hypertension. It is known that activation of poly(ADP-ribose) polymerase enzyme (PARP) plays an important role in the development of postinfarction as well as long-term hypertension induced heart failure. In this study, we examined whether PARP-inhibitor (L-2286) treatment could prevent the development of hypertensive cardiopathy in SHRs. 6-week-old SHR animals were treated with L-2286 (SHR-L group) or placebo (SHR-C group) for 24 weeks. Wistar-Kyoto rats were used as aged-matched, normotensive controls (WKY group). Echocardiography was performed, brain-derived natriuretic peptide (BNP) activity and blood pressure were determined at the end of the study. We detected the extent of fibrotic areas. The amount of heat-shock proteins (Hsps) and the phosphorylation state of Akt-1Ser473, glycogen synthase kinase (GSK)-3betaSer9, forkhead transcription factor (FKHR)Ser256, mitogen activated protein kinases (MAPKs), and protein kinase C (PKC) isoenzymes were monitored. The elevated blood pressure in SHRs was not influenced by PARP-inhibitor treatment. Systolic left ventricular function and BNP activity did not differ among the three groups. L-2286 treatment decreased the marked left ventricular (LV) hypertrophy which was developed in SHRs. Interstitial collagen deposition was also decreased by L-2286 treatment. The phosphorylation of extracellular signal-regulated kinase (ERK)1/2Thr183-Tyr185, Akt-1Ser473, GSK-3betaSer9, FKHRSer256, and PKC epsilonSer729 and the level of Hsp90 were increased, while the activity of PKC alpha/betaIIThr638/641, zeta/lambda410/403 were mitigated by L-2286 administration. We could detect signs of LV hypertrophy without congestive heart failure in SHR groups. This alteration was prevented by PARP inhibition. Our results suggest that PARP-inhibitor treatment has protective effect already in the early stage of hypertensive myocardial remodeling

Application of Surface Roughness Data for the Evaluation of Depth Profile Measurements of Nanoscale Multilayers

A secondary neutral mass spectrometric (SNMS) depth profile study of electrodeposited Co/Cu multilayers was performed. Depth profile measurements were performed both in the conventional way (i.e., starting the sputtering from the final deposit surface) and in the reverse manner (i.e., detaching the multilayers from the substrate and starting the analysis from the substrate side, which was very smooth as compared to the final deposit surface). The latter method could yield significantly larger intensity fluctuations in the SNMS spectra. Surface roughness data were measured with atomic force microscopy (AFM) for multilayers with different bilayer numbers but otherwise exhibiting the same layer structure as those used for the depth profiling. The experimental AFM surface roughness evolution was used to calculate the result of the depth profile measurements quantitatively. An excellent agreement was obtained between this calculation and the SNMS measurements. It was shown that the decrease in the intensity fluctuations during the depth profile analysis stems mainly from the increase in surface roughness of the samples studied, especially in the conventional sputtering mode. It was also concluded that the thickness fluctuation of the entire multilayer deposit and that of each layer are strongly correlated

Quantum rings as electron spin beam splitters

Quantum interference and spin-orbit interaction in a one-dimensional mesoscopic semiconductor ring with one input and two output leads can act as a spin beam splitter. Different polarization can be achieved in the two output channels from an originally totally unpolarized incoming spin state, very much like in a Stern-Gerlach apparatus. We determine the relevant parameters such that the device has unit efficiency.Comment: 4 pages, 3 figures; minor change