Poly[bis­[μ-1,4-bis­(imidazol-1-ylmeth­yl)benzene]dichloridocadmium(II)]

The title compound, [CdCl2(C14H14N4)2]n, has a slightly distorted octa­hedral coordination geometry, formed by four N atoms from 1,4-bis­(imidazol-1-ylmeth­yl)benzene ligands and two Cl atoms, giving a two-dimensional network. The Cd atom lies on a centre of inversion

Subcellular Localization and RNA Interference of an RNA Methyltransferase Gene from Silkworm, Bombyx Mori

RNA methylation, which is a form of posttranscriptional modification, is catalyzed by S-adenosyl-L-methionone-dependent RNA methyltransterases (RNA MTases). We have identified a novel silkworm gene, BmRNAMTase, containing a 369-bp open reading frame that encodes a putative protein containing 122 amino acid residues and having a molecular weight of 13.88 kd. We expressed a recombinant His-tagged BmRNAMTase in E. coli BL21 (DE3), purified the fusion protein by metal-chelation affinity chromatography, and injected a New Zealand rabbit with the purified protein to generate anti-BmRNAMTase polyclonal antibodies. Immunohistochemistry revealed that BmRNAMTase is abundant in the cytoplasm of Bm5 cells. In addition, using RNA interference to reduce the intracellular activity and content of BmRNAMTase, we determined that this cytoplasmic RNA methyltransferase may be involved in preventing cell death in the silkworm

Centrifuge and three-dimensional numerical modelling of steep CDG slopes reinforced with different sizes of nail heads

Soil nailing has been widely used for improving slope stability over the last three decades around the world and is currently the predominant method used for upgrading the stability of existing soil cut slopes in Hong Kong. Although interaction between soil and nails has been investigated widely, only few studies were conducted on the role of nail heads. Therefore, the objectives of this research are to further improve the fundamental understanding of the behaviour of nailed slopes and to investigate the role of nail heads in improving slope stability and reducing ground deformation. In this research, a series of CDG dense fill model slopes reinforced with different sizes of nail heads including grillage were destabilized by controlling long-term transient seepage in centrifuge. The prototype slope angle and height were 650 and 15m, respectively. Pore water pressures, slope deformation, axial nail forces and contact pressures between soil and nail heads were measured. Pore water pressure transducers were modified into tensiometers to measure high suction in centrifuge. A four-stage procedure was developed to saturate the tensiometers. Furthermore, an experimental framework was estabilished to identify whether a tensiometer had been desaturated or not. Three-dimensional coupled numerical simulations using ABAQUS were conducted to back-analyse the centrifuge test results. The three-dimensional numerical simulations considered the coupled effects of soil deformation and pore water pressure changes. It is found that, a global failure was evident in the unreinforced slope after being subjected to long-term transient seepage. Installation of soil nails prevented the formation of the global failure but not a tension crack at the crest. The presence of nail heads prevented the global failure and the formation of the crack after even over two years of transient seepage. With the greater sizes of nail heads, (a) crest settlements decreased, (b) the mobilised axial force at the nail head on each nail and a total of each mobilised maximum axial nail force (Tmax) increased, (c) the location of the Tmax shifted towards the slope surface, and (d) the normalized contact pressures increased at the quasi-steady state. The global failure which occurred in the unreinforced slope in centrifuge was reasonably consistent with numerical simulations. General trends in crest settlements and axial forces at the quasi-steady state were also captured in the numerical simulations

Rare earth Ce-modified (Ti,Ce)/a-C:H carbon-based film on WC cemented carbide substrate

WC cemented carbide suffers severe wear in water environments. A novel carbon-based film could be a feasible way to overcome this drawback. In this study, a rare earth Ce-modified (Ti,Ce)/a-C:H carbon-based film is successfully prepared on WC cemented carbide using a DC reactive magnetron sputtering process. The microstructure, mechanical properties, and tribological behavior of the as-prepared carbon-based film are systematically investigated. The results show that the doping Ti forms TiC nanocrystallites that are uniformly dispersed in the amorphous carbon matrix, whereas the doping Ce forms CeO2 that exists with the amorphous phase in the co-doped (Ti,Ce)/a-C:H carbon-based film. The mechanical properties of this (Ti,Ce)/a-C:H film exhibit remarkable improvements, which could suggest higher hardness and elastic modulus as well as better adhesive strength compared to solitary Ti-doped Ti/a-C:H film. In particular, the as-prepared (Ti,Ce)/a-C:H film presents a relatively low friction coefficient and wear rate in both ambient air and deionized water, indicating that (Ti,Ce)/a-C:H film could feasibly improve the tribological performance of WC cemented carbide in a water environment

Exploiting carbon-based (Cr,Ce)/a-C: H nanocomposite film on cemented WC

Cemented tungsten carbide (WC) has widely served in modern industry because of its outstanding characteristics, while it could suffer from severely wear both under ambient air and water environments. To exploit a novel carbon‐based film should be a feasible way to modify the surface of cemented WC and overcome these shortcomings. In the present study, the Cr/Ce co‐incorporated (Cr,Ce)/a‐C:H carbon‐based film was successfully deposited on cemented WC. The microstructure and mechanical properties of films were systematically characterized, and their tribological behaviors were tested in ambient air and deionized water environment. The results showed that (Cr,Ce)/a‐C:H film dominated by the typical amorphous structure and the doping Cr existed with the metallic Cr nanocrystallites as well as Ce formed CeO2. The (Cr,Ce)/a‐C:H film could possess good mechanical performances, which could own higher hardness, elastic module, low internal stress, and better adhesive strength. Especially, the as‐prepared (Cr,Ce)/a‐C:H film could present relatively lower friction coefficient and wear rate compared to uncoated cemented WC both under ambient air and deionized water environment, indicating that the Cr/Ce co‐doped (Cr,Ce)/a‐C:H film could be an effective method to modify the surface of cemented WC so as to improve the friction and wear performances of cemented WC materials

Characterization and Expression Profiling of Neuropeptides and G-Protein-Coupled Receptors (GPCRs) for Neuropeptides in the Asian Citrus Psyllid, <i>Diaphorina citri</i> (Hemiptera: Psyllidae)

Neuropeptides are endogenous active substances that widely exist in multicellular biological nerve tissue and participate in the function of the nervous system, and most of them act on neuropeptide receptors. In insects, neuropeptides and their receptors play important roles in controlling a multitude of physiological processes. In this project, we sequenced the transcriptome from twelve tissues of the Asian citrus psyllid, Diaphorina citri Kuwayama. A total of 40 candidate neuropeptide genes and 42 neuropeptide receptor genes were identified. Among the neuropeptide receptor genes, 35 of them belong to the A-family (or rhodopsin-like), four of them belong to the B-family (or secretin-like), and three of them are leucine-rich repeat-containing G-protein-coupled receptors. The expression profile of the 82 genes across developmental stages was determined by qRT-PCR. Our study provides the first investigation on the genes of neuropeptides and their receptors in D. citri, which may play key roles in regulating the physiology and behaviors of D. citri

Characterization of intersecting and bifurcating rolling contact fatigue (RCF) cracks in railway rails using ACFM sensor

Rolling contact fatigue (RCF) cracks are threatening to the security of railway rails. Alternating current field measurement (ACFM) is an electromagnetic non-destructive method for RCF cracks detecting and the sizing algorithm has been developed for single and uniform arranged RCF cracks. However, non-uniform cracks with different propagation angles, e.g. intersecting and bifurcating cracks, are difficult to be identified and characterized using the algorithm. In this paper, modelling of ACFM responses on non-uniform RCF cracks are discussed. A novel ACFM By signal and the method for identifying intersecting and bifurcating cracks are proposed. Results show that By signal is more beneficial to detect complex arranged RCF cracks and is more sensitive to variations of intersecting/bifurcating angles and positions than conventional Bx and Bz signals. By signal is promising for sizing intersecting/bifurcating RCF cracks and responses of By signals can contribute to the establishment of sizing algorithm for complex arranged RCF cracks