Structure and electrochemical behaviors of a series of Co-B alloys

A series of Co_xB (x = 1, 2, 3) alloys were prepared by arc melting, the phase structure of the alloys were characterized by X-ray diffraction (XRD). The electrochemical experimental results demonstrated that the Co_xB (x = 1, 2, 3) series alloys showed excellent cycling stability, the capacity retention was 94.2%, 93.6% and 93.8% in the 100th cycle, respectively, as the cobalt content decreased. The CoB alloy electrode showed very good electrochemical reversibility in cyclic voltammetry (CV) curves, the oxidation and reduction peaks resembled the pure cobalt element powder electrode. The electrode mechanism was discussed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), using pure CoB alloy cast electrode. From the SEM, after first and second cycle, the surface became porous and pulverous; also, the oxidation state of Co changed through XPS, after second cycle, the Co of 0 oxidation state could not be found on the surface. Based on the experiment, a proper mechanism was proposed: on this condition, the discharge capacity may due to the Co(OH)₂/Co reaction, which happened on the porous surface as the boron dissolved when the cycle increased.     

宜兴建材竹产业刮起市场旋风

竹乡产业化的突破口在哪里?“以竹代木”建材拓开了大市场,每年自产的毛竹根本“喂不饱”,还要从其他地方引进;连续几年竹建材销售过亿元,出口创汇上千万美元;业内人士称,这种全新的产业业态将使竹业重新洗牌。     

浅谈实验室重结晶提纯固体方法改进

传统重结晶方法产品回收率低耗时长,采用改进方法进行重结晶,结果表明产品回收率比传统方法提高40%,所需时间大幅缩短。     

Roles of Voltage-Gated Tetrodotoxin-Sensitive Sodium Channels NaV1.3 and NaV1.7 in Diabetes and Painful Diabetic Neuropathy

Diabetes mellitus (DM) is a common chronic medical problem worldwide; one of its complications is painful peripheral neuropathy, which can substantially erode quality of life and increase the cost of management. Despite its clinical importance, the pathogenesis of painful diabetic neuropathy (PDN) is complex and incompletely understood. Voltage-gated sodium channels (VGSCs) link many physiological processes to electrical activity by controlling action potentials in all types of excitable cells. Two isoforms of VGSCs, Na_V1.3 and Na_V1.7, which are encoded by the sodium voltage-gated channel alpha subunit 3 and 9 (Scn3A and Scn9A) genes, respectively, have been identified in both peripheral nociceptive neurons of dorsal root ganglion (DRG) and pancreatic islet cells. Recent advances in our understanding of tetrodotoxin-sensitive (TTX-S) sodium channels Na_V1.3 and Na_V1.7 lead to the rational doubt about the cause–effect relation between diabetes and painful neuropathy. In this review, we summarize the roles of Na_V1.3 and Na_V1.7 in islet cells and DRG neurons, discuss the link between DM and painful neuropathy, and present a model, which may provide a starting point for further studies aimed at identifying the mechanisms underlying diabetes and painful neuropathy.     

Antiviral Activity of a Novel Compound CW-33 against Japanese Encephalitis Virus through Inhibiting Intracellular Calcium Overload

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, has five genotypes (I, II, III, IV, and V). JEV genotype I circulates widely in some Asian countries. However, current JEV vaccines based on genotype III strains show low neutralizing capacities against genotype I variants. In addition, JE has no specific treatment, except a few supportive treatments. Compound CW-33, an intermediate synthesized derivative of furoquinolines, was investigated for its antiviral activities against JEV in this study. CW-33 exhibited the less cytotoxicity to Syrian baby hamster kidney (BHK-21) and human medulloblastoma (TE761) cells. CW-33 dose-dependently reduced the cytopathic effect and apoptosis of JEV-infected cells. Supernatant virus yield assay pinpointed CW-33 as having potential anti-JEV activity with IC₅₀ values ranging from 12.7 to 38.5 μM. Time-of-addition assay with CW-33 indicated that simultaneous and post-treatment had no plaque reduction activity, but continuous and simultaneous treatments proved to have highly effective antiviral activity, with IC₅₀ values of 32.7 and 48.5 μM, respectively. CW-33 significantly moderated JEV-triggered Ca²⁺ overload, which correlated with the recovery of mitochondria membrane potential as well as the activation of Akt/mTOR and Jak/STAT1 signals in treated infected cells. Phosphopeptide profiling by LC-MS/MS revealed that CW-33 upregulated proteins from the enzyme modulator category, such as protein phosphatase inhibitor 2 (I-2), Rho GTPase-activating protein 35, ARF GTPase-activating protein GIT2, and putative 3-phosphoinositide-dependent protein kinase 2. These enzyme modulators identified were associated with the activation of Akt/mTOR and Jak/STAT1 signals. Meanwhile, I-2 treatment substantially inhibited the apoptosis of JEV-infected cells. The results demonstrated that CW-33 exhibited a significant potential in the development of anti-JEV agents.     

On the mechanism of enhancing the nucleation behavior of UNCD films by Mo-coating

Enhanced nucleation behavior for ultra-nanocrystalline diamond on Si-substrates via the utilization of Mo-coating was observed. Spectroscopic examinations indicated that the mechanism of enhancement is the formation of Mo₂C phase, which hindered the inward diffusion of carbon species into the substrate materials. The diamonds may either nucleate directly on Mo₂C-layer or via the formation of transition phases, the graphite. The incoming carbons may also react with Mo₂C phase to form MoC phase or form the graphite phase prior to the induction of diamond nuclei. In all cases, the carbons accumulated rapidly due the presence of a Mo₂C (or MoC) layer, triggering the formation of diamond nuclei.     

Pulmonary toxicity and translocation of nanodiamonds in mice

Because of the possible health threat of nanodiamonds (NDs) to organisms, the pulmonary toxicity and translocation of NDs in different sizes in mice were investigated after intratracheal instillation administration. Biochemical assays, ultrastructural and histopathological evaluations of the lungs of the control and the ND exposed mice were carried out at 1, 7, 14 or 28 days post-exposure. Exposure to 1.0 mg/kg NDs with an average diameter of 4 nm produced a temporary lung index increase at 1 day post-exposure. NDs did not have evident adverse effects in the lungs within the studied period according to histopathological and ultrastructural investigations. Furthermore, no lipid peroxidation of the lung was observed. On the whole, intratracheally instilled NDs are of low pulmonary toxicity. In addition, the amount of NDs in alveolar decreased with time elapsed and the macrophages burdened with NDs were clearly observed in the bronchia from 1 day to 28 days post-exposure. Thus we affirm the critical role of alveolar macrophages in the main excretion pathway of NDs from the lungs, i.e. they engulf the NDs, migrate upward to the trachea by escalator/mucociliary system and finally enter the pharynx.     

Near net-shape/net-dimension ZrC/W-based composites with complex geometries via rapid prototyping and Displacive Compensation of Porosity

ZrC/W-based composites with complex shapes have been fabricated by combining rapid prototyping methods for synthesizing porous WC preforms with the shape/dimension-preserving, reactive infiltration-based Displacive Compensation of Porosity (DCP) process. Two automated rapid prototyping methods were examined: (i) computer-numerical-controlled machining of porous WC powder compacts, and (ii) 3D printing of WC powder. After binder removal and partial sintering (to neck the WC particles), the shaped, porous, and rigid preforms were exposed to molten Zr₂Cu at 1150–1300 °C and ambient pressure. Upon infiltration, the Zr in the melt underwent a displacement reaction with WC to yield more voluminous ZrC and W products that filled prior pores (reaction-induced densification). The resulting ZrC/W-based composites retained the shapes and dimensions (to within 1%) of the WC preforms. This work demonstrates, for the first time, that rapid preform prototyping can be integrated with the DCP process to generate dense, ultrahigh-melting carbide/refractory metal composites with tailorable near net-shapes and -dimensions.     

Selective Adsorption of Adenosine and Guanosine by a β‐Cyclodextrin/Layered Double Hydroxide Intercalation Compound

A film of carboxymethyl‐β‐cyclodextrin‐intercalated Zn–Al layered double hydroxide (CMCD–LDH) was investigated for selective adsorption of the nucleosides adenosine (A) and guanosine (G). The effects of pH value and adsorption time on the adsorption behavior were studied. The CMCD–LDH film shows a higher selectivity for G than A under identical conditions of G and A, which results from the ability of selective recognition of the interlayer CMCD. The kinetic studies show that adsorption of A and G by the CMCD–LDH film can be described satisfactorily by the slab diffusion model. Both the values of diffusion coefficient (D) and adsorption capability (q_e) of G by the CMCD–LDH film are larger than those of A, demonstrating the selective adsorption of the CMCD–LDH film for nucleosides. Due to its easy preparation and manipulation, this film is expected to be successfully applied in the field of selective adsorption and separation.     

One-step synthesis of barium hexaferrite nano-powders via microwave-assisted sol–gel auto-combustion

Single phase barium hexaferrite nano-powders have been innovatively one-step synthesized via a microwave-assisted sol–gel auto-combustion in a specially designed quartz vessel using citric acid and ethylene diamine tetraacetic acid as composite chelating agents and freeze-drying technique to remove sols’ moisture. The auto-combustion product powder is characterized by fluffy particle aggregates with the crystallites ranging from 50 to 100 nm in diameter and containing single magnetic domains for each with a low apparent coercive field of 260 Oe and a high saturation magnetization of 64.1 emu/g. The direct formation of barium hexaferrite is believed to result from the effective improvement in the spatial distribution homogeneity of metal ions and oxidant in the gels. Moreover, the quartz vessel with barium hexaferrite ceramic pad on sample's support and film-strips on its interior wall can effectively build up a favorable temperature environment to promote the direct formation of barium hexaferrite with microwave assistance during the gel's uniform auto-combustion.