Genetic pattern and demographic history of cutlassfish (Trichiurus nanhaiensis) in South China Sea by the influence of Pleistocene climatic oscillations.

Trichiurus nanhaiensis is one of the most important commercial fish species in the South China Sea. This study aimed to investigate the level of genetic variation and population genetic structure of T. nanhaiensis in the South China Sea for the first time, using 281 individuals collected from seven locations along the coast of mainland China, Taiwan, and Hainan Island. A high level of haplotype diversity and low nucleotide diversity were detected in the mitochondrial DNA cyt b gene and nuDNA RYR 3 gene. The overall expected heterozygosity (He = 0.693) among the seven populations ranged from 0.681 to 0.706 in microsatellite DNA data, which revealed high levels of genetic diversity. Significant genetic differentiation was found in Taidong populations in Taiwan, revealing the prevention of gene flow caused by the Kuroshio Current. Two major lineages based on the cyt b gene suggested that the Taiwan Strait acted as a geographic barrier for T. nanhaiensis during the glacier periods in the late Pleistocene. The Bayesian skyline plot also revealed that population demographic expansion of T. nanhaiensis was estimated to have occurred in 0.1 Mya. Our results indicated that all populations of T. nanhaiensis had experienced a recent genetic bottleneck following recent expansion based on ABC analysis.

Demographic history and population genetic structure of Anisakis pegreffii in the cutlassfish Trichiurus japonicus along the coast of mainland China and Taiwan.

Studying the genetic diversity of nematode parasite populations is crucial to gaining insight into parasite infection dynamics and informing parasite phylogeography. Anisakiasis is a zoonotic disease caused by the consumption of infectious third-stage larvae (L3) of Anisakis spp. carried by marine fish. In the present study, a total of 206 mitochondrial DNA sequences (cytochrome c oxidase 2, cox2) were used to study the genetic diversity, genetic structure, and historical demography of twelve A. pegreffii populations from Trichiurus japonicas along the coast of mainland China and Taiwan. Two distinct evolutionary lineages of A. pegreffii and no significant genealogical structures corresponding to sampling localities suggested that isolation in the marginal seas shaped their patterns of phylogeographic distribution along the coast of mainland China and Taiwan during glaciation with lower sea levels. Furthermore, pairwise FST values and AMOVA did not indicate any significant genetic differentiation among groups with no relation to the geographic area, which might be attributed to fewer barriers to gene flow as well as large population sizes. The results of the neutrality test, mismatch distribution, and Bayesian skyline plot analyses showed that entire population underwent population expansion during the late Pleistocene. Analysis of the demographic history revealed that A. pegreffii underwent historical lineage diversification and admixture due to secondary contact based on ABC analysis. The present research represents the first definitive population structure and demographic history across sampling locations of A. pegreffii along the coast of mainland China and Taiwan.

Complete mitogenomes of four Trichiurus species: A taxonomic review of the T.lepturus species complex.

Four Trichiurus species, T.japonicus, T.lepturus, T.nanhaiensis, and T.brevis, from the coasts of the China Seas, have been identified and their entire mitochondrial genomes (mitogenomes) have been sequenced by next-generation sequencing technology. A comparative analysis of five mitogenomes was conducted, including the mitogenome of T.gangeticus. The mitogenomes contained 16.568-16.840 bp and encoded 36 typical mitochondrial genes (13 protein-coding, 2 ribosomal RNA-coding, and 21 transfer RNA-coding genes) and two typical noncoding control regions. Although tRNAPro is absent from Trichiurus mitogenomes, when compared with the 22 tRNAs reported in other vertebrates, the gene arrangements in the mitogenomes of the studied species are consistent with those in most teleost mitogenomes. The full-length sequences and protein-coding genes (PCGs) in the mitogenomes of the five species had obvious AT biases and negative GC skew values. Our study indicate that the specimens in the Indian Ocean are neither T.lepturus nor T.nanhaiensis but they are T.gangeticus; the Trichiurus species composition in the Indian Ocean is totally different from that in Pacific and Atlantic oceans; there are at least two Trichiurus species in Indian Ocean; and the worldwide systematics and diversity of the genus Trichiurus need to be reviewed.

Characterization of the complete mitochondrial genome of the coral reef fish, Hemigymnus melapterus (Pisces: Labridae) and its phylogenetic implications.

Hemigymnus melapterus belongs to the family Labridae, which inhabit in coastal and continental shelf waters. The entire mitochondrial genome of H. melapterus is 16,527 base pairs (bp) in length and contained 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. The overall base composition is 27.56% A, 25.58% T, 30.02% C, and 16.85% G, showing AT-rich feature (53.14%). Phylogenetic analysis based on 13 protein-coding genes shows the H. melapterus has the closest evolutionary relationship with Stethojulis strigiventer. This work provides valuable genome variation information, which will be useful for phylogenetic analysis and population genetics research.

Nanoporous Adsorption Effect on Alteration of the Li+ Diffusion Pathway by a Highly Ordered Porous Electrolyte Additive for High-Rate All-Solid-State Lithium Metal Batteries.

Solid polymer electrolytes (SPEs) have shown extraordinary promise for all-solid-state lithium metal batteries with high energy density and flexibility but are mainly limited by low ionic conductivity and their poor stability with lithium metal anodes. In this work, we propose a highly ordered porous electrolyte additive derived from SSZ-13 for high-rate all-solid-state lithium metal batteries. The nanoporous adsorption effect provided by the highly ordered porous nanoparticles in the poly(ethylene oxide) (PEO) electrolyte is found to significantly improve the Li+ conductivity (1.91 × 10-3 S cm-1 at 60 °C, 4.43 × 10-5 S cm-1 at 20 °C) and widen the electrochemical stability window to 4.7 V vs Li+/Li. Meanwhile, the designed PEO-based electrolyte demonstrates enhanced stability with the lithium metal anode. Through systematically increasing Li+ diffusion, widening the electrochemical stability window, and enhancing the interfacial stability of the SSZ-composite electrolyte (CPE) electrolyte, the LiFePO4/SSZ-CPE/Li cell is optimized to deliver high rate capability and stable cycling performance, which demonstrates great potential for all-solid-state energy storage application.

High-Strength Internal Cross-Linking Bacterial Cellulose-Network-Based Gel Polymer Electrolyte for Dendrite-Suppressing and High-Rate Lithium Batteries.

Lithium is a promising anode material for high energy density batteries. However, the growth of lithium dendrite causes serious safety issues, which inhibits the application of lithium anode. Herein, a novel gel polymer electrolyte based on high-strength internal cross-linking bacterial cellulose network was prepared via an environmentally friendly and simple fast freeze-drying method. The as-obtained gel polymer electrolyte demonstrates an excellent lithium ion conductivity of 4.04 × 10-3 S cm-1 with an exceptional lithium ion transference number of 0.514 at 25 °C. The lithium metal battery with this gel polymer electrolyte shows an initial reversible capacity of 141.2 mA h g-1 with a capacity retention of 104.2% (compared with the initial reversible capacity) after 150 cycles at 0.5 C. An average reversible capacity of 75.2 mA h g-1 is maintained at high rate of 9 C. Moreover, this gel polymer electrolyte possesses superior mechanical strength of 49.9 MPa with a maximum strain of 56.33%. Therefore, the vertical growth of lithium dendrite is effectively suppressed. This research indicates the potential of applying low cost bacterial cellulose into high performance energy storage devices.

Method Using Water-Based Solvent to Prepare Li7La3Zr2O12 Solid Electrolytes.

Li-garnet Li7La3Zr2O12 (LLZO) is a promising candidate of solid electrolytes for high-safety solid-state Li+ ion batteries. However, because of its high reactivity to water, the preparation of LLZO powders and ceramics is not easy for large-scale amounts. Herein, a method applying water-based solvent is proposed to demonstrate a possible solution. Ta-doped LLZO, that is, Li6.4La3Zr1.4Ta0.6O12 (LLZTO), and its LLZTO/MgO composite ceramics are made by attrition milling, followed by a spray-drying process using water-based slurries. The impacts of parameters of the method on the structure and properties of green and sintered pellets are studied. A relative density of ∼95%, a Li-ion conductivity of ∼3.5 × 10-4 S/cm, and uniform grain size LLZTO/MgO garnet composite ceramics are obtained with an attrition-milled LLZTO/MgO slurry that contains 40 wt % solids and 2 wt % polyvinyl alcohol binder. Li-sulfur batteries based on these ceramics are fabricated and work under 25 °C for 20 cycles with a Coulombic efficiency of 100%. This research demonstrates a promising mass production method for the preparation of Li-garnet ceramics.

Long Straczekite δ-Ca0.24 V2 O5 ⋠H2 O Nanorods and Derived ß-Ca0.24 V2 O5 Nanorods as Novel Host Materials for Lithium Storage with Excellent Cycling Stability.

Nanorods of δ-Ca0.24 V2 O5 ⋅H2 O, a straczekite group mineral with an open double-layered structure, have been successfully fabricated by a facile hydrothermal method and can be transformed into the tunnel ß geometry (ß-Ca0.24 V2 O5 ) through a vacuum annealing treatment. The generated ß-Ca0.24 V2 O5 still preserves the nanorod construction of δ-Ca0.24 V2 O5 ⋅H2 O without substantial sintering and degradation of the nanostructure. As cathode materials, both calcium vanadium bronzes exhibit high reversible capacity, good rate capability, as well as superior cyclability. Compared with the hydrated vanadium bronze, the ß-Ca0.24 V2 O5 nanorods show better cycling performance (81.68 and 97.93 % capacity retention after 200 cycles at 100 and 400 mA g-1 , respectively) and excellent long-term cyclic stability with an average decay of 0.035 % per cycle over 500 cycles at 500 mA g-1 . Note that the double-layered δ-Ca0.24 V2 O5 ⋅H2 O electrode irreversibly converts into ß-Cax V2 O5 phase during the initial Li+ insertion/extraction process, while in contrast, the ß-phase calcium vanadium bronze electrode shows excellent structural stability during cycling. The excellent electrochemical performance demonstrates that the two calcium vanadium bronzes are potential cathode candidates for rechargeable lithium-ion batteries.

Sulfonic Groups Originated Dual-Functional Interlayer for High Performance Lithium-Sulfur Battery.

The lithium-sulfur battery is one of the most prospective chemistries in secondary energy storage field due to its high energy density and high theoretical capacity. However, the dissolution of polysulfides in liquid electrolytes causes the shuttle effect, and the rapid decay of lithium sulfur battery has greatly hindered its practical application. Herein, combination of sulfonated reduced graphene oxide (SRGO) interlayer on the separator is adopted to suppress the shuttle effect. We speculate that this SRGO layer plays two roles: physically blocking the migration of polysulfide as ion selective layer and anchoring lithium polysulfide by the electronegative sulfonic group. Lewis acid-base theory and density functional theory (DFT) calculations indicate that sulfonic groups have a strong tendency to interact with lithium ions in the lithium polysulfide. Hence, the synergic effect involved by the sulfonic group contributes to the enhancement of the battery performance. Furthermore, the uniformly distributed sulfonic groups working as active sites which could induce the uniform distribution of sulfur, alleviating the excessive growth of sulfur and enhancing the utilization of active sulfur. With this interlayer, the prototype battery exhibits a high reversible discharge capacity of more than 1300 mAh g-1 and good capacity retention of 802 mAh g-1 after 250 cycles at 0.5 C rate. After 60 cycles at different rates from 0.2 to 4 C, the cell with this functional separator still recovered a high specific capacity of 1100 mAh g-1 at 0.2 C. The results demonstrate a promising interlayer design toward high performance lithium-sulfur battery with longer cycling life, high specific capacity, and rate capability.

Carbon Disulfide Cosolvent Electrolytes for High-Performance Lithium Sulfur Batteries.

Development of lithium sulfur (Li-S) batteries with high Coulombic efficiency and long cycle stability remains challenging due to the dissolution and shuttle of polysulfides in electrolyte. Here, a novel additive, carbon disulfide (CS2), to the organic electrolyte is reported to improve the cycling performance of Li-S batteries. The cells with the CS2-additive electrolyte exhibit high Coulombic efficiency and long cycle stability, showing average Coulombic efficiency >99% and a capacity retention of 88% over the entire 300 cycles. The function of the CS2 additive is 2-fold: (1) it inhibits the migration of long-chain polysulfides to the anode by forming complexes with polysulfides and (2) it passivates electrode surfaces by inducing the protective coatings on both the anode and the cathode.

Suppressing the dissolution of polysulfides with cosolvent fluorinated diether towards high-performance lithium sulfur batteries.

The dissolution and shuttle of polysulfides in electrolytes cause severe anode corrosion, low coulombic efficiency, and a rapid fading of the capacity of lithium-sulfur batteries. Fluorinated diether (FDE) was selected as a cosolvent in traditional ether electrolytes to suppress the dissolution of polysulfides. The modified electrolytes lead to a negligible solubility of polysulfides, as well as decreased corrosion of the lithium anode. In an optimal system, the cells show improved cycling performance with an average coulombic efficiency of above 99% and a highly stable reversible discharge capacity of 701 mA h g-1 after 200 cycles at a 0.5C rate. A combination of electrochemical studies and X-ray photoelectron spectroscopy demonstrates the sulfur reduction mechanism with three voltage plateaus.

[Review on Analytical Methods of Doping Elements in Synthetic Crystals].

During the synthesis of crystal material, specific dopant can enhance the qualities and performance of crystals, while the types, concentrations and distributions of doping elements also have significant influence on the structures and properties of artificial crystals. Hence, it is very important to determine the concentrations of doping elements for further improving the crystal material formulas, crystal growth process, andits quality control. Currently, the analysis techniques for doping elements' characterization include atomic spectrometry, X-ray fluorescence spectrometry, inorganic mass spectrometry, electron probe microanalysis, etc. The principles, advantages and disadvantages of these techniques are discussed in this paper. Considering the specialties and scope of application, it is necessary to choose the suitable methods to improve the efficiency and accuracy. Meanwhile, the developing trends of analysis methods for doping elements are also prospected.

Compound Method to Disperse CaCO3 Nanoparticles to Nano-Size in Water.

The invalidation of CaCO3 nanoparticles (nCaCO3) is often caused by the fact of agglomeration and inhomogeneous dispersion which limits its application into water-based drilling muds for low permeability reservoirs such as coalbed methane reservoir and shale gas/oil reservoir. Effective methods to disperse nCaCO3 to nano-size (≤ 100 nm) in water have seldom been reported. Here we developed a compound method containing mechanical stirring, ultrasonic treatment, the use of surfactant and stabilizer to disperse nCaCO3 in water. It comprises the steps adding 2% nCaCO3, 1% sodium dodecyl sulfonate (SDS), 2% cetyltrimethyl ammonium bromide (CTAB), 2% OP-10, 3% to 4% biopolymer (XC) in water successively, stirring it at a shear rate of 6000 to 8000 r/min for 15 minutes and treating it with ultrasonic at a frequency of 28 KHz for 30 to 40 minutes. The dispersed nCaCO3 was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and particle size distribution (PSD) tests. We found that nCaCO3 could be dispersed to below 100 nm in water and the medium value of nCaCO3 was below 50 nm. This method paved the way for the utilization of nCaCO3 in drilling fluid and completion fluid for low permeability reservoirs such as coal seams and shale gas/oil formations.