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Ganglioside GM1 is a glycosphingolipid found on mammalian cell membranes, and it is involved in ischemic encephalopathy, spinal cord injury and neurodegenerative diseases. Fatty acids, as a structure module of GM1, have been reported to affect its physiological function and neurite growth activity. Due to the limitation of preparation methods, the function of GM1 derivatives containing different fatty acids in nerve cells has not been systematically studied. To discover novel GM1 derivatives as nerve growth-promoting agents, we developed an efficient SA_SCDase enzymatic synthetic system of GM1 derivatives, yielding twenty GM1 derivatives with unsaturated fatty acid chains in high total yields (16-67%). Subsequently, the neurite outgrowth activities of GM1 derivatives were assessed on Neuro2a Cells. Among all the GM1 derivatives, GM1 (d18:1/C16:1) induced demonstrably neurite outgrowth activity. The subsequent RNA-sequencing (RNA-seq) and Western blot analysis was then performed and indicated that the mechanism of nerve cells growth involved cholesterol biosynthesis regulation by up-regulating SREBP2 expression or ERBB4 phosphorylation to activate the PI3K-mTOR pathway.

A novel chemo-enzymatic synthetic method for UDP-α-6-N3-glucose was developed by combining the versatility of chemical synthesis and natural enzyme stereo-selectivity of Bifidobacterium longum (BLUSP). This flexible and efficient platform expanded the substrate scope for UDP-sugars on an improved scale, particularly for UDP-sugar substrates containing bioorthogonal functional groups.

O-Linked N-acetylglucosamine (O-GlcNAc) is an abundant posttranslationalmonosaccaride-modification found on Ser or Thr residues of intracellular proteins in most eukaryotes. The dynamic nature of O-GlcNAc has enabled researchers to modulate the stoichiometry of O-GlcNAc on proteins in order to investigate its function. Cell permeable small moleculars have proven invaluable tools to increase O-GlcNAc levels. Herein, using in vitro substrate screening, we identified GlcNAcF3 as an OGT-accepted but OGA-resistant sugar mimic. Cellular experiments with cell-permeable peracetylated-GlcNAcF3 (Ac4GlcNAcF3) displayed that Ac4GlcNAcF3 was a potent tool to increase O-GlcNAc levels in several cell lines. Further, NIH3T3 cells interfered with OGT (siOGT) showed significant decreasing of O-GlcNAc levels with Ac4GlcNAcF3 treatment, indicating O-GlcNAcF3 was an OGT-dependent modification. In addition, cellular toxic assay confirmed O-GlcNAcF3 production has no significant effect on cell proliferation or viability. Thus, Ac4GlcNAcF3 represents a safe and dual regulator for both OGT and OGA, which will benefit the study of O-GlcNAc.

Propyl gallate (propyl 3, 4, 5-trihydroxybenzoate; PG) was introduced as a new type of collector for diasporic bauxite flotation. The flotation performance of PG for diaspore and kaolinite was evaluated by comparing PG with sodium oleate (NaOl) as a typical collector through micro flotation tests. The results indicated that PG had higher collection ability for diaspore than for kaolinite at 15 mg/L and pH 7–9. Compared with NaOl, PG also exhibited higher selectivity for diaspore against kaolinite. Analyses of zeta potentials, adsorption amount, Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectra (XPS) revealed that PG adsorbed onto diaspore surfaces through chemical adsorption and hydrogen bonding, whereas PG hardly adsorbed onto kaolinite surfaces. Specifically, PG chelated with Al atoms on the diaspore surfaces by forming five-member rings through its ortho oxygens. These findings indicated that PG could be adopted as a novel collector for diaspore flotation and the activated phenolic hydroxyl groups also offered new insights for the development of flotation collectors.

Annealing regulation plays an important role in improving the mechanical and dynamic properties of bulk metallic glass (BMG), but the influence of annealing on the tribological properties of Zr-based BMG hasn't been investigated. In this study, we comparably investigated the tribological properties of the Zr-based BMG (Zr61Ti2Cu25Al12) under different annealing degrees. The result shows that the anti-friction property of the BMG weakens with the increase of the annealing degree, but their anti-wear property presents an opposite trend. This study makes a contribution to understanding the relationship between the annealing degree and tribological properties, which means the BMG can be further optimized for the application of tribology by annealing regulation.

In nickel hydrometallurgical operations, the removal of iron from process liquors was critical, with the method of choice commonly being crystallization (precipitation). In this paper special attention was given to the magnetite precipitate. Potential/pH diagram for Fe–H2O system was derived at 100 °C, and indicated that the iron ion may precipitate as magnetite at the lower oxidation potential. And the crystallization experiments proved that the iron ion partly precipitate as magnetite by slow oxidation at pH 2.0–2.2 and temperature 90–100 °C. The precipitates could be efficiently separated from the solutions by magnetic flocculation and separation. Further, analyses with Environmental scanning electron microscopy (ESEM) and X-ray Diffraction (XRD) provided a fundamental understanding of the magnetite precipitation process.

The presence of Pb2+ can activate cassiterite flotation, however, its biotoxicity may lead to environmental issues. Therefore, the feasibility of using Zn2+ instead of Pb2+ in cassiterite flotation was investigated in this study. The effects and mechanism of Zn2+ on the floatability of cassiterite were analyzed using benzohydroxamic acid (BHA) as the collector. The results indicated there was a higher recovery of cassiterite in the presence of Zn2+ than in the presence of Pb2+. The maximum recovery of cassiterite in the presence of Zn2+ was 90.54%. This was attributed to an increase in the adsorption quantity of BHA on the cassiterite surface with Zn2+. The maximum growth range was 4.47 × 10-6 mol/g. Further chemistry analysis of the solution indicated that BHA and Zn2+ were mainly present in the form of BHA molecules and Zn(OH)+ at pH 7.5–8.0. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) confirmed that Zn(OH)+ reacted with OH– on the cassiterite surface to form a Zn-O bond. Then, this metallic bonding combined with BHA molecules to generate a new type of chelate ring (-Sn-O-Zn-BHA). This structure made BHA attach more firmly on the cassiterite surface, causing a rise in the recovery of cassiterite.

In this study, a novel alkaline cycle leaching and MgNH4AsO4 precipitation technology was used to remove arsenic in arsenic–containing copper and cobalt slag. The phase analysis results indicated the arsenic species mostly existed in the original slag as Cu-As alloy. By adopting NaOH-H2O2 leaching method, the arsenic leaching reached as high as 94.5% under the optimum conditions. The XRD results indicated that copper in the Cu-As alloy was oxidized to be Cu(OH)2 in high concentration NaOH solution. And the optimum conditions were established as: NaOH concentration, 2 mol/L; leaching temperature, 25℃; H2O2 concentration, 5%; and liquid-solid ratio (L/S), 9:1. Thermodynamic analysis showed that it was feasible to selectively precipitate arsenate in alkaline leaching solution in the form of MgNH4AsO4. The XRD results confirmed that the arsenic in the filter residue mainly existed in the form of MgNH4AsO4·6H2O, which has good crystallinity, contributing to a better arsenic and alkali separation. Under the optimum conditions, the content of arsenic in the purified liquid and purified residue were 39 mg/L and 24.15%, respectively. Thus, the purified alkaline solution could be circulated for the leaching process, which is beneficial to the cost reduction and environment protection.

In order to effectively separate galena and jamesonite and improve the recovery during the mixing flotation, the interaction mechanisms between the minerals and the collector of diethyl dithiocarbamate (DDTC) were investigated. Single mineral flotation test was organized to research the effect of pulp pH value on the flotation behavior of galena and jamesonite. Electrochemistry property of the interaction of these two minerals with DDTC was investigated by cyclic voltammetry and Tafel tests. Flotation test shows that the recovery of jamesonite in high alkaline pulp is strongly depressed by lime (Ca(OH)2). The cyclic voltammetry and Tafel tests results show that the interaction between galena and DDTC is an electrochemical process. High pH value has little influence on the interaction between galena and DDTC, while it has great effect on jamesonite due to self-oxidation and specific adsorption of OH− and CaOH+ on jamesonite surface. Non-electroactive hydroxyl compound and low-electroconductive calcium compounds cover the surface of jamesonite, which impedes electron transfer and DDTC adsorption, thus leads to very low floatability of jamesonite.

Collector 733, a sodium soap (C 12 – 16 COONa) is widely used industrially for scheelite flotation. Low selectivity of 733 collector is always observed. In this study, a collector mixture of 733 and MES (sodium fatty acid methyl ester sulfonate) demonstrated a high selectivity for the flotation of scheelite from calcite and fluorite. An optimal mass ratio 4:1 of 733:MES was found, producing a 65.76% WO 3 concentrate grade with a recovery of 66.04% from a feed material containing only 0.57% WO 3 . In addition, the effect of water hardness and water glass addition were studied. The results indicated that the presence of Ca 2+ or Mg 2+ had little effect on the adsorption of the collector mixture at the scheelite surface. Addition of water glass for depressing calcite and fluorite had no significant effect on the adsorption of the collector mixture on the scheelite surface. The advantages of this new collector mixture (733+MES) include lower cost, low dosage, high tolerance against water hardness and high selectivity, and this collector mixture has great potential for industrial application.

Pyrrhotite is a potential source of S2− for the sulfide precipitation of nonferrous metal ions in hydrometallurgy and waste water treatment. In this study, different pyrrhotite crystals were prepared using zero-valent iron and sulfur to determine the effects of the pyrrhotite's structure on the sulfide precipitation of copper ions. The results indicate that the sulfide precipitation of copper ions highly depends on the crystal structure and crystallinity of pyrrhotite. Monoclinic pyrrhotite was found to be the most effective for copper sulfide precipitation, which can be used for the selective precipitation of copper ions from arsenic wastewater. More than 96% copper ions were removed with little loss of arsenic, contributing to a copper product of 20.2% Cu and 0.7% As, which can serve as raw materials of copper metallurgy. X-ray diffraction analysis showed the presence of CuS and (CuxFe1−x)S, indicating that most copper ions precipitated as CuS and some copper ions entered the FeS lattice by a lattice substitution reaction. Therefore, monoclinic pyrrhotite may provide an alternative solution for the selective precipitation of copper from arsenic wastewater.

The collecting power of tertiary amines (DRN, DEN and DPN) on kaolinite follows the order of DEN>DPN>DRN. After reacting with DRN, DEN and DPN, the surface potentials of kaolinite increase remarkably, and the recruitments caused by collectors also follow the order of DEN>DPN>DRN. The results of dynamics simulation show that the geometries of substituent groups bonding to N are deflected and twisted, and some of bond angles are changed when tertiary amines cations adsorb on kaolinite (001) surface. Based on the results of dynamics simulations and quantum chemistry calculations, the electrostatic forces between three tertiary amines cations and 4×4×3 (001) plane of kaolinite are 1.38×10 −7 N (DRN 12 H + ), 1.44×10 −6 N (DEN 12 H + ), 1.383×10 −6 N (DPN 12 H + ), respectively.

The flotation behaviors of kaolinite and diaspore were investigated using N,N-dipropyl dodecyl amine (PN). Maximum recoveries of kaolinite and diaspore were about 90% and 50%, respectively. Both recoveries of kaolinite and diaspore increased with the increasing dosage of PN. On the basis of the zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions account for the charging mechanisms of surfaces of kaolinite and diaspore. The adsorption mechanism of PN on the surface of two minerals was mainly electrostatic. After reacting with PN, the zeta potential of kaolinite and diaspore both increased, and comparing with the original zeta potentials, potential of kaolinite increased much more than that of diaspore, this can explain why recovery of kaolinite is higher than that of diaspore.

The flotation behavior of kaolinite was investigated using a series of tertiary amines (DRN, DEN, DPN and DBN). Maximum recoveries of kaolinite were 93%, 88% and 84% for DEN, DPN and DRN, respectively. The recovery for DBN was very low. On the basis of the Zeta potential and FT-IR spectra, the ionization of surface hydroxyl and the isomorphic exchange of surface ions accounts for the charging mechanisms of the kaolinite surface. The adsorption mechanism of tertiary amines onto the kaolinite surface was mainly electrostatic. We determined that the IEP of kaolinite increased from 3.4 to higher values after the interaction of kaolinite with the four tertiary amines. FT-IR spectra of kaolinite changed to include sharp peaks of tertiary amines. Inductive electronic effects and space-steric effects of –CH 3 , –C 2 H 5 , –C 3 H 7 and –C 7 H 7 bound to the N atom result in different collecting powers for the four tertiary amines.

Mercapto organic compound DMPS was used as the depressant for separation of copper activated marmatite from pyrrhotite in the presence of butyl xanthate. The flotation tests of single mineral show that DMPS has strong depressing effect on pyrrhotite in the absence and presence of copper ion, but has activated effect on marmatite in the presence of copper ion. The floatability of marmatite is improved in the pH range of 2–12. The flotation test of mixture mineral shows that copper-activated marmatite can be separated efficiently from pyrrhotite using DMPS as depressant. Infrared adsorption spectra demonstrate that there are a number of function groups such as SH and SO3 in the molecular structure of DMPS. Xanthate and DMPS compete in their adsorption on sulfide minerals.