The HI gas fraction scaling relation of the Green Pea galaxies

Green Pea galaxies are compact galaxies with high star formation rates. However, limited samples of Green Pea galaxies have HI 21 cm measurements. Whether the HI gas fraction f_{HI} = M_{HI}/M_{*} of Green Pea galaxies follows the existing scaling relations between the f_{HI} and NUV-r color or linear combinations of color and other physical quantities needs checking. Using archival data of HI 21cm observations, we investigate the scaling relation of the NUV-r color with the M_{HI}/M_{*} of 38 Green Pea galaxies, including 17 detections and 21 non-detections. The HI to stellar mass ratios (f_{HI}) of Green Pea galaxies deviate from the polynomial form, where a higher HI gas fraction is predicted given the current NUV-r color, even with the emission lines removed. The blue sources (NUV-r<1) from the comparison sample (ALFALFA-SDSS) follow a similar trend. The HI gas fraction scaling relations with linear combination forms of -0.34(NUV-r) - 0.64 log(mu_{*,z}) + 5.94 and -0.77 log mu_{*,i} + 0.26 log SFR/M_{*}+8.53, better predict the HI gas fraction of the Green Pea galaxies. In order to obtain accurate linear combined forms, higher-resolution photometry from space-based telescopes is needed.Comment: 15 pages, 7 figures, to be published in RA

Role of TRPM2 channel in temporal lobe epilepsy-associated neuroinflammation

Objective To investigate the role of transient receptor potential melatonin 2 （TRPM2） ion channels in microglia and astrocytes in temporal lobe epilepsy （TLE） -associated neuroinflammation. Methods Rats were randomly divided into the control group and epilepsy group. Seizure models were induced by lithium chloride-pilocarpine in the epilepsy group， and those in the control group were injected with the same dose of saline. The TLE rats were randomly divided into 7 subgroups according to the observation time after model establishment： acute phase （3 h group， 6 h group， 1 d group， 2 d group）， latent phase （14 d group） and chronic phase （30 d group， 90 d group） subgroups （n = 5）. The expression level of TRPM2 in the hippocampus of TLE rats at different stages were detected， and the cellular localization of TRPM2 in the brain of TLE rats was investigated. BV2 and C8 cell lines were induced by hydrogen peroxide （H2O2）. The levels of IL1-β， IL-6 and TNF-α released by BV2 and C8 cells were observed by ELISA. The levels of TRPM2， poly （ADP-ribose） polymerase 1 （PARP-1）， glycogen synthase kinase-3β （GSK-3β） and phosphorylated nuclear factor-κb p65 （p-NF-κb p65） were measured in H2O2-induced BV2 and C8 cells. Meantime， the activity of Calcineurin （CaN） in H2O2-induced BV2 was observed. Results The TRPM2 expression in 2d epileptic rat hippocampus was increased （P &lt; 0.05）. The expression of TRPM2 and the release of inflammatory cytokines were increased in H2O2 induced-BV2 and C8 cells （both P &lt; 0.05）. H2O2 could up-regulate the expression of PARP-1 and p-NF-κB p65 and enhance the activity of CaN in BV2 cells （all P &lt; 0.05）. Conclusions Oxidative stress can up-regulate the expression levels of TRPM2 and pro-inflammatory cytokines in microglia and astrocytes. Oxidative stress caused by recurrent epilepsy may mediate the occurrence of TLE-associated neuroinflammation through the TRPM2/ CaN/p-NF-κB p65 pathway in microglia

A high-Q metasurface signal isolator for 1.5T surface coil magnetic resonance imaging on the go

The combination of surface coils and metamaterials remarkably enhance magnetic resonance imaging (MRI) performance for significant local staging flexibility. However, due to the coupling in between, impeded signal-to-noise ratio (SNR) and low-contrast resolution, further hamper the future growth in clinical MRI. In this paper, we propose a high-Q metasurface decoupling isolator fueled by topological LC loops for 1.5T surface coil MRI system, increasing the magnetic field up to fivefold at 63.8 MHz. We have employed a polarization conversion mechanism to effectively eliminate the coupling between the MRI metamaterial and the radio frequency (RF) surface transmitter-receiver coils. Furthermore, a high-Q metasurface isolator was achieved by taking advantage of bound states in the continuum (BIC) for extremely high-field MRI and spectroscopy. An equivalent physical model of the miniaturized metasurface design was put forward through LC circuit analysis. This study opens up a promising route for the easy-to-use and portable surface coil MRI scanners

Micro Processes Study on Structure Change in N-Pentadecane Thin Film Adsorbed on Substrate: A Molecular Dynamics Simulation

It is experimentally found that adsorbed thin film consists of chain molecules changes its structure when it is heated at temperature lower than the melting point; but the molecular micro processes are remaining unknown; here we investigated the micro processes of structure change in n-pentadecane thin film adsorbed on substrate by use of molecular dynamics simulation. We found that, at temperature 200K (lower than the melting point), the isotropic amorphous thin film becomes a crystalline thin film in which molecule chains parallel to the substrate with relaxation time of about 12000ps; however, at temperature 290K (also lower than the melting point), the thin film structure changed essentially, the molecule chains changed their orientation from parallel to the substrate becomes nearly perpendicular to the substrate with relaxation time of about 5000ps

Identification of four hub genes associated with adrenocortical carcinoma progression by WGCNA

Background Adrenocortical carcinoma (ACC) is a rare and aggressive malignant cancer in the adrenal cortex with poor prognosis. Though previous research has attempted to elucidate the progression of ACC, its molecular mechanism remains poorly understood. Methods Gene transcripts per million (TPM) data were downloaded from the UCSC Xena database, which included ACC (The Cancer Genome Atlas, n = 77) and normal samples (Genotype Tissue Expression, n = 128). We used weighted gene co-expression network analysis to identify gene connections. Overall survival (OS) was determined using the univariate Cox model. A protein–protein interaction (PPI) network was constructed by the search tool for the retrieval of interacting genes. Results To determine the critical genes involved in ACC progression, we obtained 2,953 significantly differentially expressed genes and nine modules. Among them, the blue module demonstrated significant correlation with the “Stage” of ACC. Enrichment analysis revealed that genes in the blue module were mainly enriched in cell division, cell cycle, and DNA replication. Combined with the PPI and co-expression networks, we identified four hub genes (i.e., TOP2A, TTK, CHEK1, and CENPA) that were highly expressed in ACC and negatively correlated with OS. Thus, these identified genes may play important roles in the progression of ACC and serve as potential biomarkers for future diagnosis

Aharonov-Bohm interference in topological insulator nanoribbons

Topological insulators represent novel phases of quantum matter with an insulating bulk gap and gapless edges or surface states. The two-dimensional topological insulator phase was predicted in HgTe quantum wells and confirmed by transport measurements. Recently, Bi2Se3 and related materials have been proposed as three-dimensional topological insulators with a single Dirac cone on the surface and verified by angle-resolved photoemission spectroscopy experiments. Here, we show unambiguous transport evidence of topological surface states through periodic quantum interference effects in layered single-crystalline Bi2Se3 nanoribbons. Pronounced Aharonov-Bohm oscillations in the magnetoresistance clearly demonstrate the coverage of two-dimensional electrons on the entire surface, as expected from the topological nature of the surface states. The dominance of the primary h/e oscillation and its temperature dependence demonstrate the robustness of these electronic states. Our results suggest that topological insulator nanoribbons afford novel promising materials for future spintronic devices at room temperature.Comment: 5 pages, 4 figures, RevTex forma

Transport in three-dimensional topological insulators: theory and experiment

This article reviews recent theoretical and experimental work on transport due to the surface states of three-dimensional topological insulators. The theoretical focus is on longitudinal transport in the presence of an electric field, including Boltzmann transport, quantum corrections and weak localization, as well as longitudinal and Hall transport in the presence of both electric and magnetic fields and/or magnetizations. Special attention is paid to transport at finite doping, to the $\pi$-Berry phase, which leads to the absence of backscattering, Klein tunneling and half-quantized Hall response. Signatures of surface states in ordinary transport and magnetotransport are clearly identified. The review also covers transport experiments of the past years, reviewing the initial obscuring of surface transport by bulk transport, and the way transport due to the surface states has increasingly been identified experimentally. Current and likely future experimental challenges are given prominence and the current status of the field is assessed.Comment: Review article to appear in Physica