VOx Phase Mixture of Reduced Single Crystalline V2O5: VO2 Resistive Switching

The strongly correlated electron material, vanadium dioxide (VO2), has seen considerable attention and research application in metal-oxide electronics due to its metal-to-insulator transition close to room temperature. Vacuum annealing a V2O5(010) single crystal results in Wadsley phases (VnO2n+1, n > 1) and VO2. The resistance changes by a factor of 20 at 342 K, corresponding to the metal-to-insulator phase transition of VO2. Macroscopic voltage-current measurements with a probe separation on the millimetre scale result in Joule heating-induced resistive switching at extremely low voltages of under a volt. This can reduce the hysteresis and facilitate low temperature operation of VO2 devices, of potential benefit for switching speed and device stability. This is correlated to the low resistance of the system at temperatures below the transition. High-resolution transmission electron microscopy measurements reveal a complex structural relationship between V2O5, VO2 and V6O13 crystallites. Percolation paths incorporating both VO2 and metallic V6O13 are revealed, which can reduce the resistance below the transition and result in exceptionally low voltage resistive switching.     

Presence of a metallothionein-like protein in the bovine pineal gland

Summary The high concentration of zinc in the bovine pineal gland prompted us to investigate the existence of a zinc-binding protein in this organ. In this study, we report that the subcellular distribution of zinc in the bovine pineal gland is nonuniform, with the crude nuclear, mitochondrial, microsomal, and supernatant fractions having 0.264±0.038, 0.160±0.019, 0.130±0.016, and 0.287±0.010 g zinc/mg protein, respectively. Furthermore, gel filtration studies using Sephadex G-75 and a 105,000 g supernatant fraction revealed two zinc binding protein peaks that bind 1.7 and 3.7 g Zn⁺⁺/mg protein, respectively. Furthermore, purification of the protein peak with an elution volume (ve/vo) of 2.06 on anion exchange chromatography (DEAE-A 25) yielded a single protein peak which binds 10 g zinc/mg protein. The comparative high performance liquid Chromatographic (HPLC) profiles of the zinc-induced hepatic metallothionein isoform I (retention time=17.39 min) and of the bovine pineal metallothionein-like protein isoform I (retention time=17.49 min) are similar. Since zinc is a potent inhibitor of sulfhydryl-containing enzymes and receptor sites, we investigated the effects of zinc and found that it inhibited the binding of [³H]glutamate (IC 50=80 M) and of [³H]spiroperidol (IC 50=0.6 mM) to the pineal membranes. The results of these studies are interpreted to indicate that the bovine pineal gland possesses an active and dynamic zinc homeostatic mechanism, whose precise function(s) remain(s) to be delineated.     

不同浓度口腔修复金属材料离子溶液对白假丝酵母菌生长影响

目的检测常用口腔修复金属材料离子在不同浓度、不同时间段对白假丝酵母菌菌落形成的影响,以进一步研究预防和治疗义齿性口炎的方法。方法采用液体稀释法经过8h、24h、48h测定Ni2+、Cr3+对白假丝酵母菌的抑制作用。结果 Ni2+与白假丝酵母菌培养8h、24h、48h后,在160PPm浓度下,白假丝酵母菌计数值为0;经统计学检验,在8h组80PPm和40PPm与8h组的阳性对照比较,差异均有统计学(t分别=8.84、4.85,P均<0.05);24h组80PPm和40PPm与24h组的阳性对照比较,差异均有统计学(t分别=6.76、11.01,P均<0.05);48h组80PPm和40PPm与48h组的阳性对照比较,差异均有统计学(t分别=11.96、5.41,P均<0.05);而Cr3+各组浓度之间比较,差异均无统计学意义(F=0.41,P>0.05)。结论 Ni2+最低杀菌浓度为160PPm;Ni2+在40～80PPm有抑制白假丝酵母菌生长的作用;Cr3+对白假丝酵母菌的抑制能力较弱。     

Enhancement of Ceramics Based Red-Clay by Bulk and Nano Metal Oxides for Photon Shielding Features

We prepared red clays by introducing different percentages of PbO, Bi₂O₃, and CdO. In order to understand how the introduction of these oxides into red clay influences its attenuation ability, the mass attenuation coefficient of the clays was experimentally measured in a lab using an HPGe detector. The theoretical shielding capability of the material present was obtained using XCOM to verify the accuracy of the experimental results. We found that the experimental and theoretical values agree to a very high degree of precision. The effective atomic number (Z_eff) of pure red clay, and red clay with the three metal oxides was determined. The pure red clay had the lowest Z_eff of the tested samples, which means that introducing any of these three oxides into the clay will greatly enhance its Z_eff, and consequently its attenuation capability. Additionally, the Z_eff for red clay with 10 wt% CdO is lower than the Z_eff of red clay with 10 wt% Bi₂O₃ and PbO. We also prepared red clay using 10 wt% CdO nanoparticles and compared its attenuation ability with the red clay prepared with 10 wt% PbO, Bi₂O₃, and CdO microparticles. We found that the MAC of the red clay with 10 wt% nano-CdO was higher than the MAC of the clay with microparticle samples. Accordingly, nanoparticles could be a useful way to enhance the shielding ability of current radiation shielding materials.     

Efficacy of Alkaline-Treated Soy Waste Biomass for the Removal of Heavy-Metal Ions and Opportunities for Their Recovery

In this study, soy waste biomass (SW) resulting from oil extraction was treated with alkaline solution, and the obtained material (Na-SW) was used as biosorbent for the removal of Pb(II), Cd(II), and Zn(II) ions from aqueous media. The performance of this biosorbent was examined in batch systems, at different initial metal ion concentrations and contact times (pH 3.4; 5 g of biosorbent/L). Isotherm and kinetic modeling was used to calculate the equilibrium and kinetics of the biosorption processes. The maximum biosorption capacity, calculated from the Langmuir isotherm model, followed the order Zn(II) (0.49 mmol/g) > Cd(II) (0.41 mmol/g) ≈ Pb(II) (0.40 mmol/g), while the kinetics of biosorption processes fit the pseudo-second-order model. Three cycles of biosorption/desorption were performed to estimate the reusability of Na-SW biosorbent, and the regeneration efficiency was higher than 97% in all cases. The practical applicability of Na-SW biosorbent in treating of wastewater contaminated with Pb(II), Cd(II), and Zn(II) ions was examined using simulated wastewater samples, and the main quality characteristics of the effluents obtained after treatment were evaluated. All these aspects highlight the potential applicability of Na-SW for large-scale wastewater treatment.     

新型口服铁螯合剂——地拉罗司的研究进展

地拉罗司是一种新型口服铁螯合剂,它是美国FDA批准的第一个能够常规使用的口服驱铁剂,获准在≥2岁、输血造成的慢性铁负荷过多的患者中使用,在欧洲它被推荐作为6岁以上地中海贫血铁过载患者的一线用药,国内目前正在进行临床研究。本文主要就近年来有关地拉罗司的相关研究及最新进展进行介绍。Ⅱ、Ⅲ期临床试验及药代动力学研究均表明,地拉罗司具有良好的安全性和耐受性,且显著降低心脏、肝脏铁负荷,易于被患者接受。地拉罗司常见不良反应为胃肠道症状及皮疹,但近年来报道了一些罕见不良反应事件,应引起我们的重视,尤其是针对特殊人群应谨慎用药。地拉罗司治疗适应证有所放宽,包括接受auto-SCT治疗的患者以及由Fanconi综合症所致的可逆性肾功能不全的患者。地拉罗司常用剂量并非绝对适用于每个患者,临床医师应根据实际病情及相关指标调整用药剂量;铁蛋白并不是一项唯一且可靠的监测铁螯合剂疗效及调整DFS剂量的指标。另外,本文还介绍了地拉罗司的一些新特性,例如抗真菌、抗细胞增殖等作用。     

Organometallic‐Mediated Radical Polymerization: Developing Well‐Defined Complexes for Reversible Transition Metal‐Alkyl Bond Homolysis

Organometallic‐mediated radical polymerization (OMRP) has emerged as a powerful new class of living controlled radical polymerization. In order to fulfill its potential in the polymerization of vinyl acetate (VOAc) and other challenging monomers, the effects of ancillary ligands on the metal‐alkyl bond dissociation energy in OMRP reagents must be thoroughly explored. Recent results investigating structure‐activity relationships in well‐defined cobalt, iron and chromium complexes will be discussed. The involvement of radical intermediates in oxidative addition of secondary alkyls for catalytic cross‐coupling reactions catalyzed by first row transition metals will also be examined for relevant design concepts.