Catalytically Active CoSe2 Supported on Nitrogen-Doped Three Dimensional Porous Carbon as a Cathode for Highly Stable Lithium-Sulfur Battery.

Lithium-sulfur batteries are promising secondary energy storage devices that are mainly limited by its unsatisfactory cyclability owing to inefficient reversible conversion of sulfur and lithium sulfide on the cathode during the discharge/charging process. In this study, nitrogen-doped three-dimensional porous carbon material loaded with CoSe2 nanoparticles (CoSe2 -PNC) is developed as a cathode for lithium-sulfur battery. A combination of CoSe2 and nitrogen-doped porous carbon can efficiently improve the cathode activity and its conductivity, resulting in enhanced redox kinetics of the charge/discharge process. The obtained electrode exhibits a high discharge specific capacity of 1139.6 mAh g-1 at a current density of 0.2 C. After 100 cycles, its capacity remained at 865.7 mAh g-1 thus corresponding to a capacity retention of 75.97 %. In a long-term cycling test, discharge specific capacity of 546.7 mAh g-1 was observed after 300 cycles performed at a current density of 1 C.

New strategy for expression of recombinant hydroxylated human collagen α1(III) chains in Pichia pastoris GS115.

Type III collagen is one of the most abundant proteins in the human body, which forms collagen fibrils and provides the stiff, resilient characteristics of many tissues. In this paper, a new method for secretory expression of recombinant hydroxylated human collagen α1(III) chain in Pichia pastoris GS115 was applied. The gene encoding for full-length human collagen α1(III) chain (COL3A1) without N-terminal propeptide and C-terminal propeptide was cloned in the pPIC9K expression vector. The prolyl 4-hydroxylase (P4H, EC 1.14.11.2) α-subunit (P4Hα) and ß-subunit (P4Hß) genes were cloned in the same expression vector, pPICZB. Fluorogenic quantitative PCR indicates that COL3A1 and P4H genes have been expressed in mRNA level. SDS-PAGE shows that secretory expression of recombinant human collagen α1(III) chain was successfully achieved in P. pastoris GS115. In addition, the result of amino acids composition analysis shows that the recombinant human collagen α1(III) chain contains hydroxyproline by coexpression with the P4H. Furthermore, liquid chromatography coupled with tandem mass spectrometry analysis demonstrates that proline residues of the recombinant human collagen α1(III) chain were hydroxylated in the X or Y positions of Gly-X-Y triplets.

Carboxyl-modified nanocellulose (cNC) enhances the stability of cNC/pullulan bio-nanocomposite hard capsule against moisture variation.

The quality of polysaccharide-based films and hard capsules is often affected by changes in relative humidity, manifesting as unstable water content, and changes in mechanical strength that make them brittle or soft. Herein, carboxyl-modified nanocellulose (cNC) was prepared and used as a new component to successfully improve the moisture resistance of cNC/pullulan/high-acyl gellan bio-nanocomposite hard capsules (NCPGs). Homogenously dispersed cNC in the pullulan/high-acyl gellan matrix could render the formation of more hydrogen bonds that provided additional water-binding sites and limited the free movement of pullulan and high-acyl gellan molecular chains within NCPGs. This contributed to a decreased amount of pooling adsorption water and an increased amount of Langmuir adsorption water in NCPGs, as compared to pullulan/high-acyl gellan hard capsules (PGs) without cNC. Therefore, the equilibrium moisture content (EMC) values of NCPGs decreased at 83 % relative humidity and increased at 23 % relative humidity compared to those of PGs. Together with enhanced mechanical and barrier properties, NCPGs effectively protected encapsulated amoxicillin and probiotic powder from changes in the outside humidity. Additionally, NCPGs exhibited faster drug release. This study presents a new mechanism and strategy for fabricating films and hard capsules with enhanced stability against moisture variation.

Discovery of N-(4-sulfamoylphenyl)thioureas as Trypanosoma brucei leucyl-tRNA synthetase inhibitors.

Human African trypanosomiasis (HAT) is one of the most neglected diseases in the tropic regions, which is fatal if not treated in time. There is an urgent need for new therapeutics, especially those in new chemical classes. Leucyl-tRNA synthetase (LeuRS) has been paid much attention as a recently clinically validated antimicrobial target. Our group has previously reported T. brucei LeuRS (TbLeuRS) inhibitors, including benzoxaboroles targeting the editing site and pyrrolinones targeting the synthetic site. Here we report the discovery of N-(4-sulfamoylphenyl)thioureas as a new class of TbLeuRS inhibitors. The R(1) and R(2) groups, reminiscent of the leucyl and adenyl regions of aa-AMP and aa-AMS, were optimized to result in a significant 13-fold increase of inhibitory activity (compound 19, IC50 = 13.7 µM). Aided by ligand-protein docking, the 1,3-substitution at the central phenyl ring was predicted and proved to give significantly improved activity (59, IC50 = 1.1 µM). This work provided a new scaffold for the exploration of novel inhibitors against TbLeuRS, which may become potential therapeutics for the treatment of HAT.

Investigation of the Tribological Behavior and Microstructure of Plasma-Cladded Fe-Cr-Mo-Ni-B Coating.

In this study, an Fe-Cr-Mo-Ni-B coating was prepared using plasma cladding on Cr5 steel substrate. The microstructure, phase evolution and tribological performance of the Fe-Cr-Mo-Ni-B coating were investigated. The microstructure is mainly composed of Mo2FeB2, Fe2B, α-Fe, γ-Fe and MoB. The process of phase evolution in the coating was observed in situ by HT-CLSM. The Mo2FeB2 phase with good thermodynamic stability can exist in the high-temperature liquid phase. It also has a phenomenon of connection and merging and turns into different morphology during the plasma cladding process. The hardness value of coating was much higher than the base metal, and the hardness value of Mo2FeB2 (785.5 HV) was higher than the eutectic matrix (693.2 HV). The wear mechanisms of the cladding under dry sliding were primarily caused by adhesive wear, accompanying slight oxidation wear. The Mo2FeB2 phase has an important effect on the wear resistance property.

Implanting Cobalt Atom Clusters within Nitrogen-Doped Carbon Network as Highly Stable Cathode for Lithium-Sulfur Batteries.

Realization of highly efficient sulfur electrochemistry, as well as the high capacity of lithium-sulfur (Li-S) batteries, can be achieved by the scientific construction of electrode host materials. In this study, using molten NaCl, a 3D porous nitrogen-doped carbon with uniformly embedded Co atom clusters (Co/PNC) is developed by pyrolyzing the precursors with NaCl at high temperatures. In the composite structure, a network carbon skeleton containing hierarchical pores acts as an advanced matrix for sulfur electrodes, and the doping of N and Co is subject to inhibit the shuttle of long-chain lithium polysulfides through chemical adsorption. The Co/PNC, with the optimized amount of Co, delivers an initial specific capacity of 1105.4 mAh g-1 at 0.2 C with a capacity drop of only 0.064% after the cell is charged and discharged for 300 cycles at 1 C, revealing its potential in promoting the large-scale application of Li-S batteries.

Complete mitochondrial genome of the stingless bee Lepidotrigona terminata (Hymenoptera: Meliponinae) and phylogenetic analysis.

Lepidotrigona terminata (Smith, 1878) is a stingless bee that distributed in Eastern Asia. The complete mitogenome of L. terminata (GenBank accession number MN737481) is 15,431 bp in size, including 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs genes, and a noncoding D-loop region. The D-loop region is located between ND4L and tRNAMet, different from the other two stingless bee mitogenomes previously reported. The base composition of the whole L. terminata mitogenome is 38.18% for A, 11.67% for G, 38.32% for T, and 11.83% for C, with a high AT bias of 76.50%. The present data could contribute to a detailed phylogeographic analysis of this valuable economic insect for further study in differentiating closely related species.

Chalcone-benzoxaborole hybrid molecules as potent antitrypanosomal agents.

We report the novel chalcone-benzoxaborole hybrids and their structure-activity relationship against Trypanosoma brucei parasites. The 4-NH(2) derivative 29 and 3-OMe derivative 43 were found to have excellent potency. The synergistic 4-NH(2)-3-OMe compound 49 showed an IC(50) of 0.010 µg/mL and resulted in 100% survival and zero parasitemia in a murine infection model, which represents one of the most potent compounds discovered to date from the benzoxaborole class that inhibit T. brucei growth.