C₂H <i>N</i> = 1 − 0 and N₂H⁺<i>J</i> = 1 − 0 observations of <i>Planck</i> Galactic cold clumps

Liu, X.-C.,Wu, Y.,Zhang, C.,Liu, T.,Yuan, J.,Qin, S.-L.,Ju, B.-G.,Li, L.-X. EDP Sciences 2019 Astronomy and astrophysics Vol.622 No.-

<P>A survey of C2H <I>N</I> = 1 − 0 and N2H<SUP>+</SUP><I>J</I> = 1 − 0 toward <I>Planck</I> Galactic cold clumps (PGCCs) was performed using the Purple Mountain Observatory’s 13.7 m telescope. C2H and N2H<SUP>+</SUP> were chosen to study the chemical evolutionary states of PGCCs. Among 121 observed molecular cores associated with PGCCs, 71 and 58 are detected with C2H <I>N</I> = 1 − 0 and N2H<SUP>+</SUP><I>J</I> = 1 − 0, respectively. The detected lines of most sources can be fitted with a single component with compatible <I>V</I>LSR and line widths, which confirms that these PGCC cores are very cold (with gas temperatures 9-21 K) and quiescent while still dominanted by turbulence. The ratio between the column densities of C2H and N2H<SUP>+</SUP> (<I>N</I>(C2H)/<I>N</I>(N2H<SUP>+</SUP>)) is found to be a good tracer for the evolutionary states of PGCC cores. Gas-grain chemical model can reproduce the decreasing trend of <I>N</I>(C2H)/<I>N</I>(N2H<SUP>+</SUP>) as a function of time. The cores with the lowest abundances of N2H<SUP>+</SUP> (<I>X</I>[N2H<SUP>+</SUP>] < 10<SUP>−10</SUP>) are the youngest, and have nearly constant abundances of C2H. In evolved cores with <I>X</I>[N2H<SUP>+</SUP>] ~10<SUP>−9</SUP>, abundances of C2H drop quickly as the exhaustion of carbon atoms. Although these PGCC cores are in different evolutionary states, they are all quite young (< 5 × 10<SUP>5</SUP> yr) with <I>N</I>(C2H) > <I>N</I>(N2H<SUP>+</SUP>). Mapping observations are carried out toward 20 PGCC cores. The PGCC cores in Cepheus have lower <I>N</I>(C2H)/<I>N</I>(N2H<SUP>+</SUP>) and larger line widths compared with those in Taurus. This implies that PGCC cores in Taurus are less chemically evolved than those in Cepheus.</P>

c-Cbl-Mediated Neddylation Antagonizes Ubiquitination and Degradation of the TGF-β Type II Receptor

Zuo, W.,Huang, F.,Chiang, Y.,Li, M.,Du, J.,Ding, Y.,Zhang, T.,Lee, H.,Jeong, L.,Chen, Y.,Deng, H.,Feng, X.H.,Luo, S.,Gao, C.,Chen, Y.G. Cell Press 2013 Molecular cell Vol.49 No.3

Transforming growth factor β (TGF-β) is a potent antiproliferative factor in multiple types of cells. Deregulation of TGF-β signaling is associated with the development of many cancers, including leukemia, though the molecular mechanisms are largely unclear. Here, we show that Casitas B-lineage lymphoma (c-Cbl), a known proto-oncogene encoding an ubiquitin E3 ligase, promotes TGF-β signaling by neddylating and stabilizing the type II receptor (TβRII). Knockout of c-Cbl decreases the TβRII protein level and desensitizes hematopoietic stem or progenitor cells to TGF-β stimulation, while c-Cbl overexpression stabilizes TβRII and sensitizes leukemia cells to TGF-β. c-Cbl conjugates neural precursor cell-expressed, developmentally downregulated 8 (NEDD8), a ubiquitin-like protein, to TβRII at Lys556 and Lys567. Neddylation of TβRII promotes its endocytosis to EEA1-positive early endosomes while preventing its endocytosis to caveolin-positive compartments, therefore inhibiting TβRII ubiquitination and degradation. We have also identified a neddylation-activity-defective c-Cbl mutation from leukemia patients, implying a link between aberrant TβRII neddylation and leukemia development.

Optical properties of amorphous $Si_xC_yN_z$ ternary thin films prepared by plasma enhanced chemical vapor deposition

Zhang, Z.H.,Fan, X.J.,Guo, H.X.,Zhang, W.,Zhang, C.Y.,Luo, F.Y. The Korean Vacuum Society 1998 Applied Science and Convergence Technology Vol.7 No.1

Amorphous ternary $Si_xC_yN-z$ thin films were obtained by plasma enhanced chemical vapor deposition(PECVD) using $N_2, SiH_4 \;and \;C_2H_4$ as the reaction sources. The chemical state were characterized by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy(FTIR). The optical properties of the thin films were investigated by UV-visible spectrophotometer and ellipsometer, and the optical band gaps of thin films were determined from corresponding transmittance spectra following Tauc equation.

Expression Analysis of the Mx Gene and Its Genome Structure in Chickens

Yin, C.G.,Du, L.X.,Li, S.G.,Zhao, G.P.,Zhang, J.,Wei, C.H.,Xu, L.Y.,Liu, T.,Li, H.B. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.7

Among the known interferon-induced antiviral mechanisms, the Mx pathway is one of the most powerful pathways. The Mx protein has direct antiviral activity and inhibits a wide range of viruses by blocking an early stage of the viral replication cycle. Cloning, characterization, and expression of Mx in vivo and in vitro have been conducted. The chicken Mx gene spans 21 kb and is made up of 14 exons and 13 introns, of which the promoter region was analyzed. The real-time PCR results showed that Mx expression was increased in chicken embryo fibroblasts (CEF) after 12- and 24-h induction with polyI: C. Induction of Mx expression by poly I: C in vivo revealed tissue-specific patterns among the chicken tissues tested. A trace expression of Mx was detected in healthy chicken liver tissues from adult chickens without inducement; the expression levels in the liver, heart, and gizzard were higher than in the muscle and kidney. This is the first report to demonstrate the expression of a glutathione-S-transferase-tagged-Mx fusion protein of 75 KDa, as well as the biological activity tested by SDS-PAGE and western blotting.

Microwave Absorption and Magnetic Properties of Cobalt Ferrites/Carbon Nanotubes Nanocomposites

B. B. Zhang,P. F. Wang,J. C. Xu,Y. B. Han,H. X. Jin,D. F. Jin,X. L. Peng,B. Hong,J. Li,J. Gong,H. L. Ge,Z. W. Zhu,X. Q. Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.5

Owing to the unique microstructure and the excellent dielectric properties, carbon nanotubes(CNTs) were decorated with CoFe2O4 nanoparticles to synthesize the CoFe2O4/CNTs nanocomposites by the solvothermal method. The phase structure, morphology, magnetic properties and microwave absorption performance of the as-prepared CoFe2O4/CNTs were characterized and discussed by X-ray diffraction (XRD), thermal gravity analysis (TGA), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). All results indicated that the diameter of CoFe2O4 nanoparticles decorating on the surface of CNTs increased with the solvothermal temperature. CoFe2O4/CNTs prepared at 180℃, 200℃ and 220℃ exhibited superparamagnetism, while the other samples presented ferromagnetism at room temperature. And with the increasing solvothermal temperature, the saturation magnetization and coercivity increased up to 72 emu/g and 2000 Oe for the sample prepared at 260℃ (S-26). And the reflection loss of CoFe2O4/CNTs nanocomposites increased with the solvothermal temperature up to -15.7 dB for S-26 with the bandwidth of 2.5 GHz.

Corrosion Behavior and Oxide Film Formation of T91 Steel under Different Water Chemistry Operation Conditions

( D. Q. Zhang ),( C. Shi ),( J. Li ),( L. X. Gao ),( K. Y. Lee ) 한국부식방식학회(구 한국부식학회) 2017 Corrosion Science and Technology Vol.16 No.1

The corrosion behavior of a ferritic/martensitic steel T91 exposed to an aqueous solution containing chloride and sulfate ions is investigated depending on the stimulated all-volatile treatment (AVT) and under oxygenated treatment (OT) conditions. The corrosion of T91 steel under OT condition is severe, while the corrosion under AVT condition is not. The co-existence of chloride and sulfate ions has antagonistic effect on the corrosion of T91 steel in both AVT and OT conditions. Unlike to corrosion resistance in the aqueous solution, OT pretreatment provides T91 steel lower oxidation-resistance than VAT pretreatment. From scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis, the lower corrosion resistance in the aqueous solution by VAT conditions possibly is due to the formation of pits. In addition, the lower oxidation resistance of T91 steel pretreated by OT conditions is explained as follows: the cracks formed during the immersion under OT conditions accelerated peeling-off rate of the oxide film.

초고속 THz 전자파의 emitter 로써 Cd_xZn_1-xTe Crystals

강현식,김태규,X-C Zhang 全北大學校 科學敎育硏究所 1999 과학과 과학교육 논문지 Vol.24 No.-

Cd_xZn_1-xTe crystals, especially ZnTe single crystal are the most ideal crystals for ultrafast THz electromagnetic signal sensor. Moreover, good sensors also can be good emitters by optical recification principle. So we tested these mixed crystals with THz emitter and measure several properties. Particully we've found that ZnTe crystals are good emitters for generation of THz electromagnetic waves. Also we can estimate that Cd_xZn_1-xTe crystals can be good emitters when the values of THz phase velocity and group velocity of pumping laser beam are matched.

Electronic properties of graphene on the C-decorated Si(111) surface:An ab initio study

J. Liu,C.Y. He,W. Wang,N. Jiao,C.X. Zhang,L.Z. Sun 한국물리학회 2013 Current Applied Physics Vol.13 No.7

First principles calculations based on the density functional theory are performed to study electronic structures of graphene adsorbed on clean or C-decorated Si(111) surface. Two types of surface reconstructions,2 x 2 and ffiffiffi 3p x 3p , are considered to be decorated by carbon atoms with different concentrations. We find that graphene adsorbed on ideal clean Si(111) surface tends to induce a 2 x 1reconstruction, and its electronic dispersion characteristics are preserved. Moreover, the decoration of carbon atoms on the Si(111) surface can effectively passivate the Si dangling bonds on the surface. Such decoration effects make the carbon deco

Study of the dry methane reforming process using a rotating gliding arc reactor

Wu, A.,Yan, J.,Zhang, H.,Zhang, M.,Du, C.,Li, X. Pergamon Press 2014 International journal of hydrogen energy Vol.39 No.31

Dry methane reforming (DMR) via rotating gliding arc (RGA) discharge, co-driven by a magnetic field and tangential flow, was investigated in this study. Optical emission spectroscopy (OES) was used to characterize the major active species (energetic electrons, radicals, ions, atoms and excited molecules) in the DMR chemical process. The influence of the operational conditions (applied voltage and CH<SUB>4</SUB>/CO<SUB>2</SUB> ratio) on the basic spectroscopic parameters (electron excitation temperature, electron density and rotational temperature) was determined by spectroscopic methods. The rotational and electron excitation temperatures were approximately 1100-1200 K and 1.1-1.7 eV, respectively, indicating the non-thermal equilibrium characteristics of the RGA discharge. The electron density was approximately 5-20 x 10<SUP>21</SUP> m<SUP>-3</SUP> by fitting the line shape of H<SUB>α</SUB> at 656 nm. The conversions of the reactants (CH<SUB>4</SUB> and CO<SUB>2</SUB>) and the selectivities of the products (H<SUB>2</SUB>, CO and C<SUB>2</SUB> hydrocarbon) were analyzed using a gas chromatograph (GC) under different energy inputs or feed gas proportions. The structure and morphology of carbon black produced during the chemical process was characterized by high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy, indicating the properties of electrical conductivity and high absorption capacity that can be useful for potential application.

Deletion of the Lmna Gene Induces Growth Delay and Serum Biochemical Changes in C57BL/6 Mice

Ruan, J.,Liu, X.G.,Zheng, H.L.,Li, J.B.,Xiong, X.D.,Zhang, C.L.,Luo, C.Y.,Zhou, Z.J.,Shi, Q.,Weng, Y.G. Asian Australasian Association of Animal Productio 2014 Animal Bioscience Vol.27 No.1

The A-type lamin deficient mouse line ($Lmna^{-/-}$) has become one of the most frequently used models for providing insights into many different aspects of A-type lamin function. To elucidate the function of Lmna in the growth and metabolism of mice, tissue growth and blood biochemistry were monitored in Lmna-deficient mice, heterozygous ($Lmna^{+/-}$) and wide-type ($Lmna^{+/+}$) backcrossed to C57BL/6 background. At 4 weeks after birth, the weight of various organs of the $Lmna^{-/-}$, $Lmna^{+/-}$ and $Lmna^{+/+}$ mice was measured. A panel of biochemical analyses consisting of 15 serological tests was examined. The results showed that Lmna deficient mice had significantly decreased body weight and increased the ratio of organ to body weight in most of tissues. Compared with $Lmna^{+/+}$ and $Lmna^{+/-}$ mice, $Lmna^{-/-}$ mice exhibited lower levels of ALP (alkaline phosphatase), Chol (cholesterol), CR (creatinine), GLU (glucose), HDL (high-density lipoprotein cholesterol) and higher levels of ALT (alanine aminotransferase) (p<0.05). $Lmna^{-/-}$ mice displayed higher AST (aspartate aminotransferase) values and lower LDL (lowdensity lipoprotein cholesterol), CK-MB (creatine kinase-MB) levels than $Lmna^{+/+}$ mice (p<0.05). There were no significant differences among the three groups of mice with respect to BUN (blood urea nitrogen), CK (creatine kinase), Cyc C (cystatin C), TP (total protein), TG (triacylglycerols) and UA (uric acid) levels (p>0.05). These changes of serological parameters may provide an experimental basis for the elucidation of Lmna gene functions.