Coupling MoSe2 with Non-Stoichiometry Ni0.85 Se in Carbon Hollow Nanoflowers for Efficient Electrocatalytic Synergistic Effect on Li-O2 Batteries.

Li-O2 batteries could deliver ultra-high theoretical energy density compared to current Li-ion batteries counterpart. The slow cathode reaction kinetics in Li-O2 batteries, however, limits their electrocatalytic performance. To this end, MoSe2 and Ni0.85 Se nanoflakes were decorated in carbon hollow nanoflowers, which were served as the cathode catalysts for Li-O2 batteries. The hexagonal Ni0.85 Se and MoSe2 show good structural compatibility with the same space group, resulting in a stable heterogeneous structure. The synergistic interaction of the unsaturated atoms and the built-in electric fields on the heterogeneous structure exposes abundant catalytically active sites, accelerating ion and charge transport and imparting superior electrochemical activity, including high specific capacities and stable cycling performance. More importantly, the lattice distances of the Ni0.85 Se (101) plane and MoSe2 (100) plane at the heterogeneous interfaces are highly matched to that of Li2 O2 (100) plane, facilitating epitaxial growth of Li2 O2 , as well as the formation and decomposition of discharge products during the cycles. This strategy of employing nonstoichiometric compounds to build heterojunctions and improve Li-O2 battery performance is expected to be applied to other energy storage or conversion systems.

Optimizing Eg Orbital Occupancy of Transition Metal Sulfides by Building Internal Electric Fields to Adjust the Adsorption of Oxygenated Intermediates for Li-O2 Batteries.

Li-O2 batteries are acknowledged as one of the most promising energy systems due to their high energy density approaching that of gasoline, but the poor battery efficiency and unstable cycling performance still hinder their practical application. In this work, hierarchical NiS2 -MoS2 heterostructured nanorods are designed and successfully synthesized, and it is found that heterostructure interfaces with internal electric fields between NiS2 and MoS2 optimized eg orbital occupancy, effectively adjusting the adsorption of oxygenated intermediates to accelerate reaction kinetics of oxygen evolution reaction and oxygen reduction reaction. Structure characterizations coupled with density functional theory calculations reveal that highly electronegative Mo atoms on NiS2 -MoS2 catalyst can capture more eg electrons from Ni atoms, and induce lower eg occupancy enabling moderate adsorption strength toward oxygenated intermediates. It is evident that hierarchical NiS2 -MoS2 nanostructure with fancy built-in electric fields significantly boosted formation and decomposition of Li2 O2 during cycling, which contributed to large specific capacities of 16528/16471 mAh g-1 with 99.65% coulombic efficiency and excellent cycling stability of 450 cycles at 1000 mA g-1 . This innovative heterostructure construction provides a reliable strategy to rationally design transition metal sulfides by optimizing eg orbital occupancy and modulating adsorption toward oxygenated intermediates for efficient rechargeable Li-O2 batteries.

Design of High-Capacity MoS3 Decorated Nitrogen Doped Carbon Coated Cu2 S Electrode Structures with Dual Heterogenous Interfaces for Outstanding Sodium-Ion Storage.

The hierarchical Cu2 S@NC@MoS3 heterostructures have been firstly constructed by the high-capacity MoS3 and high-conductive N-doped carbon to co-decorate the Cu2 S hollow nanospheres. During the heterostructure, the middle N-doped carbon layer as the linker facilitates the uniform deposition of MoS3 and enhances the structural stability and electronic conductivity. The popular hollow/porous structures largely restrain the big volume changes of active materials. Due to the cooperative effect of three components, the new Cu2 S@NC@MoS3 heterostructures with dual heterogenous interfaces and small voltage hysteresis for sodium ion storage display a high charge capacity (545 mAh g-1 for 200 cycles at 0.5 A g-1 ), excellent rate capability (424 mAh g-1 at 15 A g-1 ) and ultra-long cyclic life (491 mAh g-1 for 2000 cycles at 3 A g-1 ). Except for the performance test, the reaction mechanism, kinetics analysis, and theoretical calculation have been performed to explain the reason of excellent electrochemical performance of Cu2 S@NC@MoS3 . The rich active sites and rapid Na+ diffusion kinetics of this ternary heterostructure is beneficial to the high efficient sodium storage. The assembled full cell matched with Na3 V2 (PO4 )3 @rGO cathode likewise displays remarkable electrochemical properties. The outstanding sodium storage performances of Cu2 S@NC@MoS3 heterostructures indicate the potential applications in energy storage fields.

CoS2 Nanoparticles Anchored on MoS2 Nanorods As a Superior Bifunctional Electrocatalyst Boosting Li2 O2 Heteroepitaxial Growth for Rechargeable Li-O2 Batteries.

Developing an excellent bifunctional catalyst is essential for the commercial application of Li-O2 batteries. Heterostructures exhibit great application potential in the field of energy catalysis because of the accelerated charge transfer and increased active sites on their surfaces. In this work, CoS2 nanoparticles decorated on MoS2 nanorods are constructed and act as a superior cathode catalyst for Li-O2 batteries. Coupling MoS2 and CoS2 can not only synergistically enhance their electrical conductivity and electrochemical activity, but also promote the heteroepitaxial growth of discharge products on the heterojunction interfaces, thus delivering high discharge capacity, stable cycle performance, and good rate capability.

Atomic Bridging Structure of Nickel-Nitrogen-Carbon for Highly Efficient Electrocatalytic Reduction of CO2.

To meet strategic applications, electrochemical reduction of CO2 into value-added chemical molecules would be improved by the rational design of advanced electrocatalysts with atomically dispersed active sites. Herein an electrospun-pyrolysis cooperative strategy is presented to not only modulate the porous structure of the carbon support for favorable charge and mass transfer, but also adjust the bridging structure of atomically dispersed metal species. Typically, the experimental results and theoretical calculations revealed that the unique chemical structure of binuclear nickel bridging with nitrogen and carbon atoms (namely Ni2 -N4 -C2 ) tunes the electronic nature of the d-states for the optimal adsorption of carbon dioxide and intermediates, thus inducing the substantial enhancement of CO2 reduction via the thermodynamically more favorable pathway. The identification of such a structure demonstrates the large space to modulate the atomic bridging status for optimizing electrocatalysis.

Comparative study of whole exome sequencing-based copy number variation detection tools.

BACKGROUND: With the rapid development of whole exome sequencing (WES), an increasing number of tools are being proposed for copy number variation (CNV) detection based on this technique. However, no comprehensive guide is available for the use of these tools in clinical settings, which renders them inapplicable in practice. To resolve this problem, in this study, we evaluated the performances of four WES-based CNV tools, and established a guideline for the recommendation of a suitable tool according to the application requirements. RESULTS: In this study, first, we selected four WES-based CNV detection tools: CoNIFER, cn.MOPS, CNVkit and exomeCopy. Then, we evaluated their performances in terms of three aspects: sensitivity and specificity, overlapping consistency and computational costs. From this evaluation, we obtained four main results: (1) The sensitivity increases and subsequently stabilizes as the coverage or CNV size increases, while the specificity decreases. (2) CoNIFER performs better for CNV insertions than for CNV deletions, while the remaining tools exhibit the opposite trend. (3) CoNIFER, cn.MOPS and CNVkit realize satisfactory overlapping consistency, which indicates their results are trustworthy. (4) CoNIFER has the best space complexity and cn.MOPS has the best time complexity among these four tools. Finally, we established a guideline for tools' usage according to these results. CONCLUSION: No available tool performs excellently under all conditions; however, some tools perform excellently in some scenarios. Users can obtain a CNV tool recommendation from our paper according to the targeted CNV size, the CNV type or computational costs of their projects, as presented in Table 1, which is helpful even for users with limited knowledge of computer science.

High thermoelectric performance of Ag doped SnTe polycrystalline bulks via the synergistic manipulation of electrical and thermal transport.

Ernzerhof (HSE) hybrid functional approximations based on the density functional theory (DFT) method were applied to investigate the electronic band structures of SnTe. First principles calculations indicate that Ag substitution in SnTe could effectively modify the valence band structures and decrease the energy separation between valence bands, ΔEVBL-Σ, which will enhance the Seebeck coefficient. All the fabricated Ag doped SnTe samples show the same crystal structure as cubic SnTe. Compared to the pure SnTe sample, the Ag doped ones exhibit greatly enhanced thermoelectric performance, especially at high temperatures, with the highest figure-of-merit of around 1.35 achieved at 900 K, by concurrent optimization of the electrical and thermal transport properties.

Electron localization in niobium doped CaMnO3 due to the energy difference of electronic states of Mn and Nb.

The electron localization in Nb-doped CaMnO3 is analyzed in terms of the space and energy distribution of electronic states employing first-principles calculations. The energy difference of Mn 3d states and Nb 4d states makes NbO6 octahedra impede electrical conduction, so the random distribution of Nb in lattices leads to the localization of electrons near the bottom of the conduction bands. Therefore, although more carriers are introduced when Nb-doping content increases, both the electrical conductivity and absolute thermopower decrease in Nb heavy doped CaMnO3. The calculated transport properties agree well with the experimental data, supporting the analysis of localization.

Delocalized Electronic Engineering of Ni5 P4 Nanoroses for Durable Li-O2 Batteries.

The sluggish kinetics and issues associated with the parasitic reactions of cathodes are major obstacles to the large-scale application of Li-O2 batteries (LOBs), despite their large theoretical energy density. Therefore, efficient electrocatalyst design is critical for optimizing their performance. Ni5 P4 is analyzed theoretically as a cathode material, and the downshift of the d-band center is found to enhance electron occupation in antibonding orbits, providing a valuable descriptor for understanding and enhancing the intrinsic electrocatalytic activity. In this study, it is demonstrated that incorporating additional nitrogen atoms into Ni5 P4 nanoroses regulates the electronic structure, resulting in superior electrocatalytic performance in LOBs. Further spectroscopic analysis and density functional theory calculations reveal that the incorporated nitrogen sites can effectively induce localized structure polarization, lowering the energy barrier for the production of desirable intermediates and thus enhancing battery capacity and preventing cell degradation. This approach provides a sound basis for developing advanced electrode materials with optimized electronic structures for high-performance LOBs.

Heterogeneous interface in hollow ferroferric oxide/ iron phosphide@carbon spheres towards enhanced Li storage.

Heterogeneous interface and structural engineering play important roles for electrochemical performance of lithium-ion batteries. Herein, heterostructures of hollow Fe3O4/FeP spheres coated with carbon shell (H-Fe3O4/FeP@C) are designed to enhance lithium storage performance. As bifunctional anode materials, the H-Fe3O4/FeP@C spheres show the good rate performance with 458.4 mAh g-1 at 5 A g-1 and long-cyclic performance (630.2 mAh g-1 at 2.0 A g-1 after 1000 cycles). Density functional theory calculations demonstrate that the heterogeneous interfaces from (311) plane of Fe3O4 and (002) plane of FeP possess high charge density and distinct metallic character, which can improve the conductivity, increase the adsorption energy, provide more active sites and reduce the transfer barrier of ions and electrons. Besides, hollow structure of H-Fe3O4/FeP@C not only alleviates the volume expansion during lithiation/delithiation process but also shortens the diffusion distance of Li ions. In addition, the ex-situ X-ray diffraction and X-ray photoelectron spectroscopy are used to reveal the electrochemical Li storage mechanisms of H-Fe3O4/FeP@C. This work provides a novel route for design and preparation of Fe-based heterostructures for various energy storage systems in the future.

Recent advances in heterostructured cathodic electrocatalysts for non-aqueous Li-O2 batteries.

Developing efficient energy storage and conversion applications is vital to address fossil energy depletion and global warming. Li-O2 batteries are one of the most promising devices because of their ultra-high energy density. To overcome their practical difficulties including low specific capacities, high overpotentials, limited rate capability and poor cycle stability, an intensive search for highly efficient electrocatalysts has been performed. Recently, it has been reported that heterostructured catalysts exhibit significantly enhanced activities toward the oxygen reduction reaction and oxygen evolution reaction, and their excellent performance is not only related to the catalyst materials themselves but also the special hetero-interfaces. Herein, an overview focused on the electrocatalytic functions of heterostructured catalysts for non-aqueous Li-O2 batteries is presented by summarizing recent research progress. Reduction mechanisms of Li-O2 batteries are first introduced, followed by a detailed discussion on the typical performance enhancement mechanisms of the heterostructured catalysts with different phases and heterointerfaces, and the various heterostructured catalysts applied in Li-O2 batteries are also intensively discussed. Finally, the existing problems and development perspectives on the heterostructure applications are presented.

Monolayer Fe3GeX2 (X = S, Se, and Te) as Highly Efficient Electrocatalysts for Lithium-Sulfur Batteries.

The high energy density, low cost, and environmental friendliness of lithium-sulfur (Li-S) batteries enable them to be promising next-generation energy storage systems. However, the commercialization of Li-S batteries is presently hindered by the bottlenecks, such as the low conductivity of sulfur species, shuttle effect of polysulfides, and poor conversion efficiency in discharging/charging processes. Here, on the basis of first-principles calculations, we predicted that the two-dimensional magnetic Fe3GeX2 (X = S, Se, and Te) monolayers are quite promising to overcome the aforesaid problems. The Fe3GeX2 monolayer has metallic electronic structures and moderate binding strength to the soluble lithium polysulfides, which are expected to improve the overall electric conductivity of sulfur species and anchor the soluble lithium polysulfides to suppress the shuttle effect. Remarkably, Fe3GeX2 monolayers show bifunctional electrocatalytic activity to the S reduction reaction and the Li2S decomposition reaction, which improves the conversion efficiency in discharging and charging processes. This finding may open up an avenue for the development of high-performance Li-S batteries.

Novel Quasi-Liquid K-Na Alloy as a Promising Dendrite-Free Anode for Rechargeable Potassium Metal Batteries.

Rechargeable potassium metal batteries are promising energy storage devices with potentially high energy density and markedly low cost. However, eliminating dendrite growth and achieving a stable electrode/electrolyte interface are the key challenges to tackle. Herein, a novel "quasi-liquid" potassium-sodium alloy (KNA) anode comprising only 3.5 wt% sodium (KNA-3.5) is reported, which exhibits outstanding electrochemical performance able to be reversibly cycled at 4 mA cm-2 for 2000 h. Moreover, it is demonstrated that adding a small amount of sodium hexafluorophosphate (NaPF6 ) into the potassium bis(fluorosulfonyl)imide electrolyte allows for the formation of the "quasi-liquid" KNA on electrode surface. Comprehensive experimental studies reveal the formation of an unusual metastable KNa2 phase during plating, which is believed to facilitate simultaneous nucleation and suppress the growth of dendrites, thereby improving the electrode's cycle lifetime. The "quasi-liquid" KNA-3.5 anode demonstrates markedly enhanced electrochemical performance in a full cell when pairing with Prussian blue analogs or sodium rhodizonate dibasic as the cathode material, compared to the pristine potassium anode. Importantly, unlike the liquid KNA reported before, the "quasi-liquid" KNA-3.5 exhibits good processability and can be readily shaped into sheet electrodes, showing substantial promise as a dendrite-free anode in rechargeable potassium metal batteries.

MnCo2 S4 -CoS1.097 Heterostructure Nanotubes as High Efficiency Cathode Catalysts for Stable and Long-Life Lithium-Oxygen Batteries Under High Current Conditions.

Constructing the heterostructures is considered to be one of the most effective methods to improve the poor electrical conductivity and insufficient electrocatalytic properties of metal sulfide catalysts. In this work, MnCo2 S4 -CoS1.097 nanotubes are successfully prepared via a reflux- hydrothermal process. This novel cathode catalyst delivers high discharge/charge specific capacities of 21 765/21 746 mAh g-1 at 200 mA g-1 and good rate capability. In addition, a favorable cycling stability with a fixed specific capacity of 1000 mAh g-1 at high current density of 1000 mA g-1 (167 cycles) and 2000 mA g-1 (57 cycles) are delivered. It is proposed that fast transmission of ions and electrons accelerated by the built-in electric field, multiple active sites from the heterostructure, and nanotube architecture with large specific surface area are responsible for the superior electrochemical performance. To some extent, the rational design of this heterostructured metal sulfide catalyst provides guidance for the development of the stable and efficient cathode catalysts for Li-O2 batteries that can be employed under high current conditions.

Transition-metal monochalcogenide nanowires: highly efficient bi-functional catalysts for the oxygen evolution/reduction reactions.

Stable bi-functional electrocatalysts for the oxygen evolution/reduction reactions (OER/ORR) are desirable for rechargeable metal-air batteries and regenerative fuel cell technologies. In this study, the electronic structures and catalytic performance of recently synthesized transition-metal monochalcogenide (MX, M = Cr, Mo, W; X = S, Se, Te) nanowires (NWs) were systemically investigated based on first-principles calculations. The results demonstrate that these MX NWs can be deemed as efficient bi-functional catalysts for the OER/ORR. In particular, the low overpotentials of CrTe NWs are even superior to those of the well-known noble catalysts. To study the origin of excellent electrocatalytic performance, we establish linear relationships between the adsorption strength of intermediates and the overpotentials. A comparison study reveals that the NWs exhibit better catalytic performance than the corresponding two-dimensional materials, indicating the superiority of the unique NW structures for catalysis. These computational results offer not only a new family of bi-functional OER/ORR catalysts, but also a promising perspective for the development of stable, low-cost and highly active non-noble electrocatalysts.

Single-atom Pt supported on holey ultrathin g-C3N4 nanosheets as efficient catalyst for Li-O2 batteries.

As for electrocatalysis, single-atom metal catalysts have been proved to lower the cost and utilize precious metals more efficiently. Herein, single-atom Pt catalyst supported on holey ultrathin g-C3N4 nanosheets (Pt-CNHS) was synthesized via a facile liquid-phase reaction of g-C3N4 and H2PtCl6. The single-atom Pt can achieve high dispersibility and stability, which can promote the utilization efficiency as well as enhance the electrochemical activity. When employed as Li-O2 batteries' cathode catalyst, Pt-CNHS exhibits excellent electrocatalytic activity. Li-O2 batteries utilizing Pt-CNHS show much higher discharge specific capacities than those with pure CNHS. Li-O2 batteries with Pt-CNHS cathode can be cycled stably for 100 times under the discharge capacity of 600 mAh g-1. Based on experimental results and density functional theory calculations, the superior electrocatalytic activity of Pt-CNHS can be ascribed to the large surface area, the enhanced electrical conductivity and the efficient interfacial mass transfer through Pt atoms and porous structure of CNHS.

Detection of False-Positive Deletions from the Database of Genomic Variants.

Next generation sequencing is an emerging technology that has been widely used in the detection of genomic variants. However, since its depth of coverage, a main signature used for variant calling, is affected greatly by biases such as GC content and mappability, some callings are false positives. In this study, we utilized paired-end read mapping, another signature that is not affected by the aforementioned biases, to detect false-positive deletions in the database of genomic variants. We first identified 1923 suspicious variants that may be false positives and then conducted validation studies on each suspicious variant, which detected 583 false-positive deletions. Finally we analysed the distribution of these false positives by chromosome, sample, and size. Hopefully, incorrect documentation and annotations in downstream studies can be avoided by correcting these false positives in public repositories.

Annealing effects on the structural and dielectric properties of (Nb + In) co-doped rutile TiO2 ceramics.

Density functional theory calculations were conducted to investigate the electronic structures of rutile Ti16O32, Ti13Nb2InO32, and Ti13Nb2InO31 systems. High density (Nb + In) co-doped rutile TiO2 ceramics were successfully prepared by one modified solid state method. XRD, XPS, Raman scattering and FT-IR measurements were performed to investigate the structural properties of the (Nb + In) co-doped rutile TiO2 ceramics annealed in different atmospheres. The lattice parameters for the (Nb + In) co-doped rutile TiO2 ceramics were enlarged slightly after they were annealed in air and oxygen. Raman scattering results indicate that the Eg modes are quite sensitive to oxygen vacancy in comparison with the other Raman active modes. The ceramics annealed in oxygen at 873 K exhibit the best dielectric performance with giant dielectric permittivity (>14 000) and small dielectric loss (<0.2) over the frequency range from 40 Hz to 1 MHz.

The PPI network analysis of mRNA expression profile of uterus from primary dysmenorrheal rats.

To elucidate the mechanisms of molecular regulations underlying primary dysmenorrhea (PD), we used our previously published mRNA expression profile of uterus from PD syndrome rats to construct protein-protein interactions (PPI) network via STRING Interactome. Consequently, 34 subnetworks, including a "continent" (Subnetwork 1) and 33 "islands" (Subnetwork 2-34) were generated. The nodes, with relative expression ratios, were visualized in the PPI networks and their connections were identified. Through path and module exploring in the network, the bridges were found from pathways of cellular response to calcium ion, SMAD protein signal transduction, regulation of transcription from RNA polymerase II promoter in response to stress and muscle stretch that were significantly enriched by the up-regulated mRNAs, to the cascades of cAMP metabolic processes and positive regulation of cyclase activities by the down-regulated ones. This link is mainly dependent on Fos/Jun - Vip connection. Our data, for the first time, report the PPI network analysis of differentially expressed mRNAs in the uterus of PD syndrome rats, to give insight into screening drugs and find new therapeutic strategies to relieve PD.

Improvement of thermoelectric properties and their correlations with electron effective mass in Cu1.98SxSe1-x.

Sulphur doping effects on the crystal structures, thermoelectric properties, density-of-states, and effective mass in Cu1.98SxSe1-x were studied based on the electrical and thermal transport property measurements, and first-principles calculations. The X-ray diffraction patterns and Rietveld refinements indicate that room temperature Cu1.98SxSe1-x (x = 0, 0.02, 0.08, 0.16) and Cu1.98SxSe1-x (x = 0.8, 0.9, 1.0) have the same crystal structure as monoclinic-Cu2Se and orthorhombic-Cu2S, respectively. Sulphur doping can greatly enhance zT values when x is in the range of 0.8≤ × ≤1.0. Furthermore, all doped samples show stable thermoelectric compatibility factors over a broad temperature range from 700 to 1000 K, which could greatly benefit their practical applications. First-principles calculations indicate that both the electron density-of-sates and the effective mass for all the compounds exhibit non-monotonic sulphur doping dependence. It is concluded that the overall thermoelectric performance of the Cu1.98SxSe1-x system is mainly correlated with the electron effective mass and the density-of-states.