低冰镍衍生的具有高结构稳定性和快速扩散动力学的钠离子掺杂层状LiNi1/3Co1/3Mn1/3O2正极

通过共沉淀法合成钠离子(Na^(+))掺杂的高稳定性Li_(1−x)NaxNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM-Na)正极材料。首先论证采用低冰镍提取镍作为合成材料镍源的可行性。其次,在化学试剂合成的NCM(Ni,Co,Mn)材料中预先引入最优含量的Na^(+),占据部分Li^(+)位点,实现具有更低Li^(+)/Ni^(2+)阳离子混排的稳定结构,从而提高其电化学性能。结果表明,当Na+掺杂量为1%(质量分数)(x=0.01)时,获得的NCM-Na正极材料在1C电流密度下,循环100次后容量保持率从76.84%提高至89.21%。特别是在5C大电流密度下,循环200次后,可逆放电比容量依然维持在110 mA·h·g^(-1)。这为杂原子掺杂耦合材料化冶金开发低成本、高性能锂离子电池三元LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)正极材料提供具有前景的策略。

Nanosensitizers for sonodynamic therapy for glioblastoma multiforme: current progress and future perspectives

Glioblastoma multiforme(GBM) is the most common primary malignant brain tumor, and it is associated with poor prognosis. Its characteristics of being highly invasive and undergoing heterogeneous genetic mutation, as well as the presence of the blood–brain barrier(BBB), have reduced the efficacy of GBM treatment. The emergence of a novel therapeutic method, namely, sonodynamic therapy(SDT), provides a promising strategy for eradicating tumors via activated sonosensitizers coupled with low-intensity ultrasound. SDT can provide tumor killing effects for deep-seated tumors, such as brain tumors. However, conventional sonosensitizers cannot effectively reach the tumor region and kill additional tumor cells, especially brain tumor cells. Efforts should be made to develop a method to help therapeutic agents pass through the BBB and accumulate in brain tumors. With the development of novel multifunctional nanosensitizers and newly emerging combination strategies, the killing ability and selectivity of SDT have greatly improved and are accompanied with fewer side effects. In this review, we systematically summarize the findings of previous studies on SDT for GBM, with a focus on recent developments and promising directions for future research.

Neurotoxic role of interleukin-17 in neural stem cell differentiation after intracerebral hemorrhage

Interleukin 17(IL-17)and its main producer,T cell receptorγδcells,have neurotoxic effects in the pathogenesis of intracerebral hemorrhage(ICH),aggravating brain injuries.To investigate the correlation between IL-17 and ICH,we dynamically screened serum IL-17 concentrations using enzyme-linked immunosorbent assay and explored the clinical values of IL-17 in ICH patients.There was a significant negative correlation between serum IL-17 level and neurological recovery status in ICH patients(r=–0.498,P<0.01).To study the neurotoxic role of IL-17,C57 BL/6 mice were used to establish an ICH model by injecting autologous blood into the caudate nucleus.Subsequently,the mice were treated with mouse neural stem cells(NSCs)and/or IL-17 neutralizing antibody for 72 hours.Flow cytometry,brain water content detection,Nissl staining,and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling results indicated that NSC transplantation significantly reduced IL-17 expression in peri-hematoma tissue,but there was no difference in T cell receptorγδcells.Compared with the ICH group,there were fewer apoptotic bodies and more Nissl bodies in the ICH+NSC group and the ICH+NSC+IL-17 group.To investigate the potential effect of IL-17 on directional differentiation of NSCs,we cultured mouse NSCs(NE-4 C)alone or co-cultured them with T cell receptorγδcells,which were isolated from mouse peripheral blood mononuclear cells,for 7 days.The results of western blot assays revealed that IL-17 secreted by T cell receptorγδcells reduced the differentiation of NSCs into astrocytes and neurons,while IL-17 neutralization relieved the inhibition of directional differentiation into astrocytes rather than neurons.In conclusion,serum IL-17 levels were elevated in the early stage of ICH and were negatively correlated with outcome in ICH patients.Animal experiments and cytological investigations therefore demonstrated that IL-17 probably has neurotoxic roles in ICH because of its inhibitory effects on the directional differentiation of NSCs.The application of IL-17 neutralizing antibody may promote the directional differentiation of NSCs into astrocytes.This study was approved by the Clinical Research Ethics Committee of Anhui Medical University of China(For human study:Approval No.20170135)in December 2016.All animal handling and experimentation were reviewed and approved by the Institutional Animal Care and Use Committee of Anhui Medical University(approval No.20180248)in December 2017.

Extraction of metals from complex sulfide nickel concentrates by low-temperature chlorination roasting and water leaching

The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process, various process parameters were studied, including the roasting temperature, the addition of NH4Cl, the roasting time, the leaching time, and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition, 95% of Ni, 98% of Cu, and 88% of Co were recovered. In addition, the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Extraction of valuable metals from low nickel matte by calcified roasting-acid leaching process

A calcified roasting-acid leaching process was developed as a highly effective method for the extraction of valuable metals from low nickel matte in the presence of CaO additive. The influences of process parameters on the metal extraction were studied, including the roasting temperature, roasting time, addition of CaO, H2SO4 concentration and liquid-solid ratio. Under the optimum condition, 94.2% of Ni, 98.1% of Cu, 92.2% of Co and 89.3% of Fe were recovered. Additionally, 99.6% of Fe was removed from the leachate as goethite by a subsequent goethite iron precipitation process. The behavior and mechanism of CaO additive in the roasting process was clarified. The role of CaO is to prevent the formation of nonferrous metal ferrite phases by a preferential reaction with Fe2O3 during the roasting process. The metal oxides(Cu O and NixCu1-xO) remained stable during high-temperature roasting and were subsequently efficiently leached using a sulfuric acid solution.

Reductive kinetics of Panzhihua ilmenite with hydrogen

The hydrogen reduction of Panzhihua ilmenite concentrate in the temperature range of 900?1050 °C was systematicallyinvestigated by thermogravimetric analysis (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. It wasshown that the products of the Panzhihua ilmenite reduced at 900 °C were metallic iron and rutile. Above 1000 °C, ferrouspseudobrookite solid solution was generated. During the reduction process, element Mg gradually concentrated to form Mg-rich zonewhich can influence the metallization process. The reduction reaction proceeded topochemically and its related reduction kineticswere also discussed. The kinetics of the reduction indicated that the rate-controlling step was the diffusion process. The apparentactivation energy of the hydrogen reduction of Panzhihua ilmenite was calculated to be 117.56 kJ/mol, which was larger than that ofsynthetic ilmenite under the same reduction condition.

Interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution

The interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution were investigated.The chalcopyrite surface was examined by scanning electron microscopy and X-ray photoelectron spectroscopy(XPS)techniques.It was found that interfacial passivation layers of chalcopyrite were formed from an iron oxide layer on top of a copper sulfide layer overlaying the bulk chalcopyrite,whereas CuFe1-xS2 or copper sulfides were formed via the preferential dissolution of Fe.The copper sulfide layer formed a new passivation layer,whereas the iron oxide layer peeled off spontaneously and partially from the chalcopyrite surface.The state of the copper sulfide layer was discussed after being deduced from the appearance of S2-,S22-,Sn2-,S0 and SO42-.A mechanism for the oxidation and passivation of chalcopyrite under different pH values and redox potentials was proposed.Accordingly,a model of the interfacial reaction on the chalcopyrite surface was constructed using a three-step reaction pathway,which demonstrated the formation and transformation of passivation layers under the present experimental conditions.

Engineering nanotheranostic strategies for liver cancer

The incidence and mortality of hepatocellular carcinoma have continued to increase over the last few years,and the medicine-based outlook of patients is poor.Given great ideas from the development of nanotechnology in medicine,especially the advantages in the treatments of liver cancer.Some engineering nanoparticles with active targeting,ligand modification,and passive targeting capacity achieve efficient drug delivery to tumor cells.In addition,the behavior of drug release is also applied to the drug loading nanosystem based on the tumor microenvironment.Considering clinical use of local treatment of liver cancer,in situ drug delivery of nanogels is also fully studied in orthotopic chemotherapy,radiotherapy,and ablation therapy.Furthermore,novel therapies including gene therapy,phototherapy,and immunotherapy are also applied as combined therapy for liver cancer.Engineering nonviral polymers to function as gene delivery vectors with increased efficiency and specificity,and strategies of co-delivery of therapeutic genes and drugs show great therapeutic effect against liver tumors,including drug-resistant tumors.Phototherapy is also applied in surgical procedures,chemotherapy,and immunotherapy.Combination strategies significantly enhance therapeutic effects and decrease side effects.Overall,the application of nanotechnology could bring a revolutionary change to the current treatment of liver cancer.

Effect of thermal exposure time on tellurium-induced embrittlement of Ni–16Mo–7Cr–4Fe alloy

The embrittlement of nickel-based structural alloys by fission-produced tellurium(Te) is a major challenge for molten salt reactors(MSR). In this study, the effects of thermal exposure time on tellurium diffusion in a candidate MSR structural alloy(Ni–16 Mo–7 Cr–4 Fe) and the consequent mechanical property degradation of the alloy were investigated through surrogate diffusion experiments at 700 °C. The results show that some tellurium reacted with the alloy to form tellurides on the surface,while some tellurium diffused into the alloy along grain boundaries. Ni_3Te_2 and CrTe were the most stable reaction products at the tested temperature, and the formation of CrTe on the surface induced the Cr depletion at grain boundaries of the alloy. The diffusion depth of Te increased gradually with thermal exposure time, and thediffusion rate kept stable within the test duration of up to3000 h. The Te diffusion in the alloy caused the embrittlement of grain boundaries, inducing crack formation and strength degradation in tensile test at room temperature.

Flotation behavior and mechanism of rutile with nonyl hydroxamic acid

The flotation and surface interaction of rutile with nonyl hydroxamic acid were investigated in this work. The results show that the adsorption density and flotation recovery of rutile have similar tendency, especially the maximum recovery and adsorption occur at pH about 7.5. In terms of Fourier transform infrared（FTIR） spectroscopic analysis, chemical adsorption is identified on the surface of rutile, where a chelate of O,O-five-membered rings with Ti^4＋ on the surface of rutile may form. Adsorption measurements, Zeta potential test, IR spectrum analyses, and solution chemistry calculations illustrate that the adsorption on the rutile surface involves both physical and chemical adsorption, while chemical adsorption is dominant.

Natural nitrogen-doped multiporous carbon from biological cells as sulfur stabilizers for lithium-sulfur batteries

In this context,we firstly synthesized a novel nitrogen-doped multiporous carbon material from renewable biological cells through a facile chemical activation with K;CO;.After sulfur impregnation,the carbon/sulfur composite achieved a sulfur content of about 67 wt%.The C/S composite as the cathode of lithium-sulfur batteries exhibited a discharge capacity of 1410 mAh/g and good capacity retention of912 mAh/g at 0.1C.These outstanding results were attributed to the synergy effect of microporous carbon and natural doping nitrogen atoms.We believe that the facile approach for the synthesis of nitrogen-doped multiporous carbon from the low-cost and sustainable biological resources will not only be applied in lithium-sulfur batteries,but also in other electrode materials.