Response of selenium-dependent glutathione peroxidase in the freshwater bivalve Anodonta woodiana exposed to 2,4-dichlorophenol,2,4,6-trichlorophenol and pentachlorophenol.

2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) pose a health risk to aquatic organism and humans, and are recognized as persistent priority pollutants. Selenium dependent glutathione peroxidase (Se-GPx) belongs to the family of selenoprotein, which acts mainly as an antioxidant role in the cellular defense system. In the current study, a Se-GPx full length cDNA was cloned from Anodonta woodiana and named as AwSeGPx. It had a characteristic codon at 165TGA167 that corresponds to selenocysteine(Sec) amino acid as U44. The full length cDNA consists of 870 bp, an open reading frame (ORF) of 585 bp encoded a polypeptide of 195 amino in which conserved domain (68LGFPCNQF75) and a glutathione peroxide-1 GPx active site (32GKVILVENVASLUGTT47) were observed. Additionally, the eukaryotic selenocysteine insertion sequence (SECIS) was conserved in the 3'UTR. The AwSeGPx amino acid sequence exhibited a high similarity with that of other Se-GPx. Real-time PCR analysis revealed that AwSeGPx mRNA had a widely distribution, but the highest level was observed in hepatopancreas. AwSeGPx mRNA expression was significantly up-regulated in hepatopancreas, gill and hemocytes after 2,4-DCP, 2,4,6-TCP and PCP exposure. Under similar environment, clams A. woodiana showed a more sensitive to PCP than that of 2,4-DCP and 2,4,6-TCP. These results indicate that AwSeGPx plays a protective role in eliminating oxidative stress derived from 2,4-DCP, 2,4,6-TCP and PCP treatment.

Transition-metal-catalyzed oxidation of metallic Sn in NiO/SnO2 nanocomposite.

It is well accepted that metallic tin as a discharge (reduction) product of SnO(x) cannot be electrochemically oxidized below 3.00 V versus Li(+)/Li(0) due to the high stability of Li2O, though a similar oxidation can usually occur for a transition metal formed from the corresponding oxide. In this work, nanosized Ni2 SnO4 and NiO/SnO2 nanocomposite were synthesized by coprecipitation reactions and subsequent heat treatment. Owing to the catalytic effect of nanosized metallic nickel, metallic tin can be electrochemically oxidized to SnO2 below 3.00 V. As a result, the reversible lithium-storage capacities of the nanocomposite reach 970 mAh g(-1) or above, much higher than the theoretical capacity (ca. 750 mAh g(-1)) of SnO2, NiO, or their composites. These findings extend the well-known electrochemical conversion reaction to non-transition-metal compounds and may have important applications, for example, in constructing high-capacity electrode materials and efficient catalysts.

Synthesis and electrochemical performance of graphene-like WS2.

Graphene-like and platelike WS2 were obtained by solid-state reactions. High-resolution (HR) TEM, BET, and Raman scattering studies show that the graphene-like WS2 is a few-layer-structured material. It exhibits better electrochemical performances than the platelike WS2. Structural characterization indicates that metallic W and Li2S are the end products of discharge (0.01 V versus Li(+)/Li), whereas metallic W and S are the recharge (3.00 V) products. In addition, X-ray absorption near-edge structure (XANES) characterization shows that the d electrons of W deviate towards the Li (or S) atom during the discharge/charge process, thus forming a weak bond between W and Li2S (or S).

Control of Gradient Concentration Prussian White Cathodes for High-Performance Potassium-Ion Batteries.

Owing to their abundant resources and low cost, potassium-ion batteries (PIBs) have become a promising alternative to lithium-ion batteries (LIBs). However, the larger ionic radius and higher mass of K+ propose a challenging issue for finding suitable cathode materials. Prussian whites (PWs) have a rigid open framework and affordable synthesis method, but they suffer quick capacity fade due to lattice volume change and structural instability during K+ insertion/extraction. Here, we prepared controllable gradient concentration KxFeaNibMn1-a-b[Fe(CN)6]y·zH2O particles via a facile coprecipitation process, demonstrating high-performance potassium-ion storage. The high-Mn content in the interior can minimize capacity loss caused by electrochemically inert Ni and achieve a high reversible capacity; meanwhile, the high-FeNi content in the exterior can alleviate the volume change of the core material upon cycling, thus enhancing structural stability. Taking the above synergistic effect, the controllable gradient concentration PWs deliver a high reversible capacity of 109.8 mAh g-1 at 100 mA g-1 and good capacity retention of 77.8% after 200 cycles. The gradient concentration PWs can retain structural integrity and stability during long-term cycling. This work provides a prospective strategy to fabricate PWs with stable structure and excellent electrochemical performance for developing high-performance PIBs.

Molecular characterization of AwSox2 from bivalve Anodonta woodiana: Elucidating its player in the immune response.

Sox2 is an embryonal stem cell Ag essential for early embryonic development, tissue homeostasis and immune regulation. In the current study, one complete Sox2 cDNA sequence was cloned from freshwater bivalve Anodonta woodiana and named AwSox2. Histological changes of testis derived from Bisphenol A (BPA) treatment were analyzed by hematoxylin and eosin staining. Expressions of AwSox2 derived from BPA, LPS and polyinosinic:polycytidylic (Poly I:C) challenge were measured by quantitative real-time PCR. The full-length cDNA of AwSox2 contained an open reading frame of 927 nucleotides bearing the typical structural features of Sox2 family. Obvious degeneration, irregular arrangement of spermatids, and clotted dead and intertwined spermatids were observed in BPA-treated groups. Administration of BPA could result in a dose-dependent up-regulation of AwSox2 expression in the male gonadal tissue of A. woodiana. In addition, expression of AwSox2 was significantly induced by LPS and Poly I:C treatment in the hepatopancreas, gill and hemocytes, compared with that of control group. These results indicated that up-regulations of AwSOx2 are closely related to apoptosis of spermatogonial stem cells derived from BPA treatment as well as enhancement of immune defense against LPS and Poly I:C challenge in A. woodiana.

Mechanism of lithium storage in MoS2 and the feasibility of using Li2S/Mo nanocomposites as cathode materials for lithium-sulfur batteries.

The most-popular strategy to improve the cycling stability and rate performance of the sulfur electrode in lithium-sulfur (Li-S) batteries is to astrict the sulfur in a conducting medium by using complicated chemical/physical processing. Lithium sulfide (Li(2)S) has been proposed as an alternative electrode material to sulfur. However, for its application, it must meet challenges such as high instability in air together with all of the drawbacks of a sulfur-containing electrode. Herein, we report the feasibility of using Li(2)S, which was obtained by electrochemical conversion of commercial molybdenum disulfide (MoS(2)) into Li(2)S and metallic molybdenium (Mo) at low voltages, as a high-performance active material in Li-S batteries. Metallic Mo prevented the dissolution of lithium polysulfides into the electrolyte and enhanced the conductivity of the sulfide electrode. Therefore, the in situ electrochemically prepared Li(2)S/Mo composite exhibited both high cycling stability and high sulfur utilization.

Enhanced Li storage performance of ordered mesoporous MoO2 via tungsten doping.

Ordered mesoporous tungsten-doped MoO(2) was synthesized by a nanocasting method. The Li storage performance of mesoporous MoO(2) is significantly improved by tungsten doping, which exhibits a reversible capacity of 700 mA h g(-1), better cycling and rate performance. This material combines the advantages of the high theoretical capacity of MoO(2) and the better electroactivity of WO(2).