Anomalous superconducting proximity effect of planar Pb-RhPb2 heterojunctions in the clean limit

Interest in superconducting proximity effect has been revived by the exploitation of Andreev states and by the possible emergence of Majorana bound states at the interface. Spectroscopy of these states has been so far restricted to just a handful of superconductor-metal systems in the diffusion regime, whereas reports in otherwise clean superconductor-superconductor heterojunctions are scarce. Here, we realize molecular beam epitaxy growth of atomically sharp planar heterojunctions between Pb and a topological superconductor candidate RhPb2 that allows us to spectroscopically image the proximity effect in the clean limit. The measured energy spectra of RhPb2 vary with the spatial separation from proximal Pb, and exhibit unusual modifications in the pairing gap structure and size that extend over a distance far beyond the coherence length. This anomalously long-range proximity (LRP) effect breaks the rotational symmetry of Cooper pair potential in real space and largely deforms the Abrikosov vortex cores. Our work opens promising avenues for fundamental studies of the Andreev physics and extraordinary states in clean superconducting heterojunctions.Comment: 8 pages, 4 figure

Expression changes and roles of matrix metalloproteinases in a rat model of traumatic deep vein thrombosis

AbstractObjectiveTo study the expression changes of matrix metalloproteinases (MMPs) in traumatic deep vein thrombosis (TDVT) in a rat model with the aid of gene chip technology and to explore the roles of MMPs in TDVT.MethodsTotally 150 Sprague Dawley rats were randomly divided into control group (n=10) and model group (n=140). Rat models of TDVT were established by clamping the femoral vein and fixing the bilateral hind limbs. Then fixation of the hip spica with plaster bandage was conducted. According to the observation phases and/or biological situations of the femoral vein thrombosis, the model rats were further divided into 7 groups. Vascular tissues were obtained from each group through noninvasive incision into the femoral vein at corresponding time points. We adopted the Trizol one-step method for total RNA extraction, Affymetrix RAT 230 2.0 array for detection of RNA expressions and fold change (FC) analysis for changes of differential expressions of MMPs in each group. The main outcome parameters measured included expressions of MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-11, MMP-12, MMP-13, MMP-14, MMP-16, MMP-23 and MMP-24. Gene array data of these MMPs were analyzed by the Affymetrix Microarray Analysis software (Version 5.0).ResultsFC analysis showed differential expressions of MMPs in each group during the course of TDVT. At the initial period of thrombosis, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-11, and MMP-24 had significantly high expression, while MMP-12, MMP-13, MMP-14, MMP-16 and MMP-23 had relatively low expression. MMPs were all highly expressed at the peak time of thrombosis. In the process of thrombus resolution, MMP-2, MMP-10, MMP-16 and MMP-24 have relatively low expression, while MMP-12, MMP-13, MMP-14, MMP-16 and MMP-23 have significantly high expression.ConclusionMMPs may affect the process of TDVT through transcription regulation of the fibrinolysis-anti-fibrinolytic system during the course of thrombosis and thrombus resolution

Observation of Coulomb blockade and Coulomb staircases in superconducting Pr0.8Sr0.2NiO2 films

Motivated by the discovery of superconductivity in the infinite-layer nickelate family, we report an experimental endeavor to clean the surface of nickelate superconductor Pr0.8Sr0.2NiO2 films by Ar+ ion sputtering and subsequent annealing, and we study their electronic structures by cryogenic scanning tunneling microscopy and spectroscopy. The annealed surfaces are characterized by nano-sized clusters and Coulomb staircases with periodicity inversely proportional to the projected area of the nanoclusters, consistent with a double-barrier tunneling junction model. Moreover, the dynamical Coulomb blockade effects are observed and result in well-defined energy gaps around the Fermi level, which correlate closely with the specific configuration of the junctions. These Coulomb blockade-related phenomena provide an alternative plausible cause of the observed gap structure that should be considered in the spectroscopic understanding of nickelate superconductors with the nano-clustered surface.Comment: 7 pages, 5 figure

A mouse line for inducible and reversible silencing of specific neurons

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Acknowledgements: We thank Dr. Joseph W. Lynch for sharing the IVMR plasmid, and Dr. Lisa M. Monteggia for sharing the AAV2-Cre plasmid. Rosa-CAG targeting vector was obtained from Addgenes. This work was supported by the Key State Research Program from Ministry of Science and Technology of China (2011CB510005, 2012CB966900, 2013CB835103), National Natural Science Foundation of China (81221001, 81200692, 81101026, 31100788, 31271182, 31030034, 91232724), Science and Technology Commission of Shanghai Municipality (12XD1404800), Shanghai Pujiang Program (12PJ1408800), Key Disciplines Group Construction Project of Pudong Health Bureau of Shanghai (PWZxq2014-04) and Sino-UK Higher Education Research Partnership for PhD Studies.Peer reviewedPublisher PD

Effect of acetone extract of Rumex japonicas Houtt on hydrogen peroxide-induced apoptosis in rat myocardial cells

Purpose: To investigate the protective effect of the acetone extract of Rumex japonicas Houtt. (AER) on rat myocardial cells.Methods: R. japonicas was extracted with 75 % aqueous ethanol by reflux to afford total extract (TER). TER was suspended in water and then extracted with acetone to afford acetone fraction of R. japonicas (AER). High performance liquid chromatography (HPLC) combined with standard substances was carried out to analyze the major constituents of AER. Apoptosis in myocardial H9c2 cell line was induced by H2O2 (100 μmol/L). The cells were treated with AER (50, 100 and 200 μg/mL, and cell viability was evaluated by the 3-（4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, while oxidative stress level in H9c2 cells was evaluated by determining levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), creatinine kinase (CK), superoxide dismutase (SOD), and catalase (CAT). Furthermore, apoptotic proteins (caspase-3, Bax and Bcl-2) in H9c2 cells were analyzed by using western blot assay.Results: Results revealed that the main components of AER are aloe-emodin, rhein, emodin, chrysophanol and physcion. AER (50, 100 and 200 μg/mL) inhibited the cell viability reduction of the H9c2 cells induced by H2O2 (p < 0.05, p < 0.01, p < 0.01, respectively). AER (50, 100 and 200 μg/mL) decreased LDH and CK contents of H9c2 cells (p < 0.01). The levels of SOD (p<0.01) and CAT (p < 0.01) were increased by AER treatments (100 and 200 μg/mL); in addition, AER (50, 100 and 200 μg/mL) decreased MDA levels (p < 0.01). Besides, the present results also revealed that AER could down-regulate caspase-3 and Bax, but up-regulated Bcl-2.Conclusion: AER alleviates apoptosis induced by H2O2 in myocardial H9c2 cells via inhibition of oxidative stress and mitochondria-mediated apoptosis. This finding suggests that AER can potentially be developed for the treatment of myocardial apoptosis.Keywords: Rumex japonicas Houtt., Myocardial cells, Apoptosis, H9c2 cell, Oxidative stres

Detection of a superconducting phase in a two-atom layer of hexagonal Ga film grown on semiconducting GaN(0001)

The recent observation of superconducting state at atomic scale has motivated the pursuit of exotic condensed phases in two-dimensional (2D) systems. Here we report on a superconducting phase in two-monolayer crystalline Ga films epitaxially grown on wide band-gap semiconductor GaN(0001). This phase exhibits a hexagonal structure and only 0.552 nm in thickness, nevertheless, brings about a superconducting transition temperature Tc as high as 5.4 K, confirmed by in situ scanning tunneling spectroscopy, and ex situ electrical magneto-transport and magnetization measurements. The anisotropy of critical magnetic field and Berezinski-Kosterlitz-Thouless-like transition are observed, typical for the 2D superconductivity. Our results demonstrate a novel platform for exploring atomic-scale 2D superconductor, with great potential for understanding of the interface superconductivity