Fabrication and Characterization of Electrodeposited Ni-SiC-h/BN Composite Coatings

Ni—SiC—h/BN composite materials were prepared by electrodeposition technique with the dispersion of SiC（10 g/L） and h/BN nanosheets（10 g/L） in a nickel sulfamate electrolytic bath.Different ratio of sodium dodecyl sulfate（SDS） and cetyltrymethyl ammonium bromide（CTAB） surfactants were used to evaluate the effect of surfactants on the properties of the electrodeposited composite coatings.The coating samples were characterized by scanning electron microscopy,X-ray diffraction,Vickers microhardness test,scratch and tribology tests.The results revealed that the co-deposition of nanoparticles was significantly influenced by surfactants during electrodeposition process.Pyramidal or polyhedral nickel crystallites were observed at higher ratio of SDS/CTAB while smaller oval grains with refined surface morphologies were obtained at lower ratio of SDS/CTAB surfactants.In addition,wt%of particles co-deposition was increased,and Vickers microhardness,wear and coefficient of friction of the electrodeposited composite coatings were improved at increased CTAB and decreased SDS contents in the electrolyte during electrodeposition process.     

Exposure to blood borne viruses and the hepatitis B vaccination status among healthcare workers in inner London

The performance of a commercially available assay for detection of hepatitis C virus (HCV) antibody in saliva samples was assessed. Samples of saliva were collected from 270 individuals whose HCV antibody status was determined by serum assay (161 HCV-positive, 109 HCV-negative). The saliva samples were tested for the presence of HCV antibodies using a modified protocol. The sensitivity was 94.4% (95% CI, 89.3-97.2%) and the specificity 99.1% (95% CI, 94.3-100%). Although the optical density in tests on HIV-positive individuals was lower than that among HIV-negative individuals, the HIV status had no significant influence on the results of the HCV assay in saliva. These findings suggest that tests on saliva can be useful in epidemiological studies for estimating the prevalence of HCV in populations that are difficult to reach.     

A yeast antiviral protein,SKI8, shares a repeated amino acid sequence pattern with β-subunits of G proteins and several other proteins

SKI8 is a yeast antiviral gene, essential for controlling the propagation of M double-stranded RNA (dsRNA) and thus for preventing virus-induced cytopathology. Our DNA sequence of SKI8 shows that it encodes a 397 amino acid protein containing two copies of a 31 amino acid repeat pattern first identified in mammalian β-transducin and Cdc4p of yeast. There are also four copies of this repeat in yeast Mak11p, necessary for M dsRNA propagation, and three copies in the putative product of the Dictyostelium AAC3 gene. Analysis of 36 cases of the repeat unit shows they have a consensus predicted structure: N–helix–sheet–turn–sheet–turn–sheet–helix–C.     

Design of filtering directional coupler with improved performance

This letter presents a filtering directional coupler (FDC) with enhanced coupling and high directivity simultaneously. The proposed FDC is composed of a pair of coupled lines instead transmission line of a directional coupler. This coupled lines resonator increases the design parameters by which even/odd mode phase velocity can be compensated to improve the directivity and coupling level. The coupling enhancement can be explained by analyzing the even mode and odd mode circuit of the proposed coupler. A prototype of the proposed coupler is designed which provides a high directivity of 44 dB for 6 dB coupling level at 1 GHz frequency. The proposed coupler is designed, fabricated, and tested.     

微弹簧圈栓塞难治性外伤性颈动脉海绵窦瘘的疗效观察

目的 探讨和研究微弹簧圈血管内栓塞难治性外伤性颈动脉海绵窦瘘的疗效。方法 回顾１３例用微弹簧圈栓塞治疗的难治性外伤性颈动脉海绵窦瘘患者。所有患者均有持续性颅内血管杂音、搏动性突眼及球结膜充血水肿。均采用微弹簧圈栓塞治疗,其中经动脉入路９例,经眼上静脉入路４例。结果 １２例术后造影瘘口消失且颈内动脉通畅。１例填入５枚微弹簧圈后,微导管脱离瘘口,反复尝试不能再次进入,术中造影瘘口仍显影,１周后球囊阻断试验阴性后闭塞颈内动脉主干。术中１例微弹簧圈解旋,将解旋部分置于患侧颈外动脉固定。术后３ ～ １２个月（平均７．５个月）对１０例患者随访了脑血管造影复查。１例复发,原因多与弹簧圈解旋后长期服用抗血小板药物均有关。结论 对于球囊闭塞困难的难治性外伤性颈动脉海绵窦瘘,微弹簧圈栓塞安全、有效。     

Electrodeposition and characterization of Ni-TiB2 composite coatings

Nickel-titanium diboride (Ni-TiB₂) composite coatings were successfully fabricated by pulse electrodeposition techniques from nickel sulfamate bath containing dispersed submicron TiB₂ particles. The effect of TiB₂ codeposition on the morphological, microstructural, microhardness and anti-corrosive properties of the composite coatings have been investigated by using scanning electron microscopy coupled with energy dispersive spectroscopy system, X-ray diffraction (XRD), vickers microhardness, and electrochemical impedance spectroscopy (EIS) techniques. Incorporation of TiB₂ particles into the nickel matrix has modified the regular crystal growth of nickel. The XRD patterns revealed that the preferred (100) crystallite orientation of pure nickel has been modified into mixed orientations by the enhancement of (111) and attenuation of (200) diffraction intensities by the incorporation of TiB₂ particles into the nickel matrix. Vickers microhardness of the Ni-TiB₂ composite coating is found to be increased which is nearly 3 times higher than pure nickel coating. The results obtained by polarization curves and EIS analysis in 3.5 wt% NaCl solution have shown the improved corrosion resistance properties of Ni-TiB₂ composite coating over pure nickel electrodeposit.     

Optical and field emission characteristics of anodic aluminium oxide/ZnO hybrid nanostructure

Arrays of ZnO nanowires (NWs) were fabricated within the well-distributed pores of anodic aluminium oxide (AAO) template by a simple chemical method. The photoluminescence (PL) and field emission (FE) properties of the AAO/ZnO NWs hybrid structure were investigated in detail. The hybrid nanostructure exhibits interesting PL characteristics. ZnO NWs exhibit UV emission at 378 nm and two prominent blue-green emissions at about 462 and 508 nm. Intense blue emission from the AAO template itself was observed at around 430 nm. Herein, for the first time we report the FE characteristics of the ZnO/AAO hybrid structure to show the influence of the AAO template on the FE property of the hybrid structure. It is found that the turn-on electric field of the vertically grown and aligned ZnO NWs within the pores of AAO template is lower than the entangled unaligned ZnO NWs extracted from the template. Although the AAO template exhibits no FE current but it helps to achieve better FE property of the ZnO NWs through better alignment. The turn-on electric field of aligned NWs was found to be 3 V μm⁻¹ at a current of 0.1 μA. Results indicate that the AAO embedded ZnO NW hybrid structure may find useful applications in luminescent and field emission display devices.     

Cellular uptake of gold nanoparticles directly cross-linked with carrier peptides by osteosarcoma cells

Nanoparticles have been extensively used for a variety of biomedical applications and there is a growing need for highly specific and efficient delivery of the nanoparticles into target cells and subcellular location. We attempted to accomplish this goal by modifying gold particles with peptide motif's that are known to deliver a 'cargo' into chosen cellular location specifically, we intended to deliver nanogold particles into cells through chemical cross-linking with different peptides known to carry protein into cells. Our results suggest that specific sequence of such 'carrier peptides' can efficiently deliver gold nanoparticles into cells when chemically cross-linked with the metal particles.     

The Corrosion and Wear Performance of Microcrystalline WC-10Co-4Cr and Near-Nanocrystalline WC-17Co High Velocity Oxy-Fuel Sprayed Coatings on Steel Substrate

The study of near-nanocrystalline cermet composite coating was performed by depositing near-nanocrystalline WC-17Co powder using the high velocity oxy-fuel spraying technique. The WC-17Co powder consists of a core with an engineered near-nano-scale WC dispersion with a mean grain size 427 nm. The powder particle contains 6 wt pct of the ductile phase Co matrix mixed into the core to ensure that the reinforcing ceramic phase WC material is discontinuous to limit debridement during wear, while the remainder of the binding phase (11 wt pct) is applied as a coating on the powder particle to improve the ductility. The tribological properties of the coating, in terms of corrosion resistance, microhardness, and sliding abrasive wear, were studied and compared with those of an industrially standard microcrystalline WC-10Co-4Cr coating with a WC mean grain size 3 μm. Results indicated that the WC-17Co coating had superior wear and corrosion resistance compared to the WC-10Co-4Cr coating. The engineered WC-17Co powder with a duplex Co layer had prevented significant decarburization of the WC dispersion in the coating, thereby reducing the intersplat microporosity necessary for initiating microgalvanic cells. The improved wear resistance was attributed to the higher hardness value of the near-nanocrystalline WC-17Co coating.     

Multifunctional greener additives for lubricating oil

In an anticipation to produce biodegradable additives with multifunctional performance for a cost‐effective lubricant composition, copolymers are synthesized by incorporating rice bran oil, peanut oil, β‐pinene in the backbone of isodecyl acrylate through microwave irradiation method using AIBN (azobisisobutyronitrile) as radical initiator. The prepared polymers are characterized by spectral techniques (IR, NMR) and SEC‐GPC analysis, thermal stability was determined by thermogravimetric analysis. Performance of the polymers as antiwear (AW), pour point depressant (PPD), viscosity modifier/viscosity index improver (VII) in different mineral base oils (SN1 and SN2) were done by standard ASTM methods. Biodegradability test of the polymers was carried out by disk diffusion (DD) and soil burial test methods. The copolymers of rice bran oil showed better viscosity index values and AW property, whereas the copolymers of peanut oil found to be most effective as PPD. Copolymers with higher concentration of green units showed better performance as viscosity modifier, pour point depressant and AW performance along with excellent biodegradability. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers