Engineering Carrier Density and Effective Mass of Plasmonic TiN Films by Tailoring Nitrogen Vacancies.

The introduction of nitrogen vacancies has been shown to be an effective way to tune the plasmonic properties of refractory titanium nitrides. However, its underlying mechanism remains debated due to the lack of high-quality single-crystalline samples and a deep understanding of electronic properties. Here, a series of epitaxial titanium nitride films with varying nitrogen vacancy concentrations (TiNx) were synthesized. Spectroscopic ellipsometry measurements revealed that the plasmon energy could be tuned from 2.64 eV in stoichiometric TiN to 3.38 eV in substoichiometric TiNx. Our comprehensive analysis of electrical and plasmonic properties showed that both the increased electronic states around the Fermi level and the decreased carrier effective mass due to the modified electronic band structures are responsible for tuning the plasmonic properties of TiNx. Our findings offer a deeper understanding of the tunable plasmonic properties in epitaxial TiNx films and are beneficial for the development of nitride plasmonic devices.

Comparative proteomic analysis of seminal plasma exosomes in buffalo with high and low sperm motility.

BACKGROUND: Exosomes are nanosized membranous vesicles secreted by various types of cells, which facilitate intercellular communication by transporting bioactive compounds. Exosomes are abundant in biological fluids including semen, and their protein composition and the potential of seminal plasma exosomes (SPEs) as fertility biomarkers were elucidated in humans, however, little information is available regarding buffalo (Bubalus bubalis). Here, we examined protein correlation between spermatozoa, seminal plasma (SP), and SPEs, and we compared and analyzed protein differences between high-motility (H-motility) and low-motility (L-motility) SPEs in buffalo. RESULTS: SPEs were concentrated and purified by ultracentrifugation combined with sucrose density gradient centrifugation, followed by verification using western blotting, nanoparticle tracking analysis, and transmission electron microscopy. Protein composition in spermatozoa, SP and SPEs, and protein difference in H- and L-motility SPEs were identified by LC-MS/MS proteomic analysis and were functionally analyzed through comprehensive bioinformatics. Many SPEs proteins originated from spermatozoa and SP, and nearly one third were also present in spermatozoa and SP. A series of proteins associated with reproductive processes including sperm capacitation, spermatid differentiation, fertilization, sperm-egg recognition, membrane fusion, and acrosome reaction were integrated in a functional network. Comparative proteomic analyses showed 119 down-regulated and 41 up-regulated proteins in L-motility SPEs, compared with H-motility SPEs. Gene Ontology (GO) enrichment of differentially expressed proteins (DEPs) showed that most differential proteins were located in sperm and vesicles, with activities of hydrolase and metalloproteinase, and were involved in sperm-egg recognition, fertilization, single fertilization, and sperm-zona pellucida binding processes, etc. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that differential proteins were mainly involved in the PPRP signaling pathway, calcium signaling pathway, and cAMP signaling pathway, among others. Furthermore, 6 proteins associated with reproduction were validated by parallel reaction monitoring analysis. CONCLUSION: This study provides a comprehensive description of the seminal plasma exosome proteome and may be of use for further screening of biomarkers associated with male infertility.

Nlrp5 and Tle6 expression patterns in buffalo oocytes and pre-implantation embryos.

Maternal-effect genes (MEGs) accumulate in oocytes during oogenesis and mediate the pre-implantation embryo developmental programme until activation of the zygote genome. Nlrp5 and Tle6 are required for normal pre-implantation and embryonic development. However, the precise function of these MEGs in buffalo (Bubalus bubalis) remains to be elucidated. The aim of this study was to characterize Nlrp5 and Tle6 sequences and analyse their mRNA and protein expression patterns in somatic tissues, oocytes and pre-implantation embryos of buffalo. The coding sequences of each gene were successfully cloned and characterized. Real-time quantitative reverse transcription PCR results revealed an absence of Nlrp5 or Tle6 transcripts in somatic tissues, with the exception of ovary. Expression levels of Nlrp5 and Tle6 in oocytes increased from the germinal vesicle stage to metaphase II stage and then gradually decreased during morula and blastocyst stages. Protein expression patterns were confirmed by immunofluorescence analysis. This study lays a foundation for further validation of the function of MEGs in buffalo.

Thermodynamics and kinetics of an oxygen adatom on pristine and functionalized graphene: insight gained into their anticorrosion properties.

The thermodynamic and kinetic stabilities of an O adatom on graphene are critical factors for the formation of oxide defects in graphene, which leads to the breakdown of a graphene protective coating. To systematically understand various behaviors of an O adatom on graphene under the space conditions, the adsorption energies, diffusion paths and barriers, and penetration paths and barriers of the O adatom on pristine and functionalized graphene (e.g., -O, -OH, -H, and -F) are calculated using density functional theory, and the electronic structures are also analyzed in depth to reveal the microscopic mechanisms. We find that chemical functionalization increases both the adsorption stability and diffusion mobility of the O adatom on graphene, implying the possibly exacerbated destructive oxidation and even breakdown of the graphene-based coating. Furthermore, the penetration of the O adatom through pristine and functionalized graphene is also calculated, the occurrence of which is proved to be impossible in reality due to the associated extremely high energetic barriers. The calculated results, revealed mechanisms, and the gained insight into the corrosion resistance of graphene will be helpful for the design, synthesis, and application of related graphene-based protective coatings.

Localized Symmetry Breaking for Tuning Thermal Expansion in ScF3 Nanoscale Frameworks.

The local symmetry, beyond the averaged crystallographic structure, tends to bring unusual performances. Negative thermal expansion is a peculiar physical property of solids. Here, we report the delicate design of the localized symmetry breaking to achieve controllable thermal expansion in ScF3 nanoscale frameworks. Intriguingly, an isotropic zero thermal expansion is concurrently engineered by localized symmetry breaking, with a remarkably low coefficient of thermal expansion of about +4.0 × 10-8/K up to 675 K. This mechanism is investigated by the joint analysis of atomic pair distribution function of synchrotron X-ray total scattering and extended X-ray absorption fine structure spectra. A localized rhombohedral distortion presumably plays a critical role in stiffening ScF3 nanoscale frameworks and concomitantly suppressing transverse thermal vibrations of fluorine atoms. This physical scenario is also theoretically corroborated by the extinction of phonon modes with negative Grüneisen parameters in rhombohedral ScF3. The present work opens an untraditional chemical modification route to achieve controllable thermal expansion by breaking local symmetries in materials.

Tunable Negative Thermal Expansion in Layered Perovskites from Quasi-Two-Dimensional Vibrations.

We identify a quasi-two-dimensional (quasi-2D) phonon mode in the layered-perovskite Ca_{3}Ti_{2}O_{7}, which exhibits an acoustic branch with quadratic dispersion. Using first-principles methods, we show this mode exhibits atomic displacements perpendicular to the layered [CaTiO_{3}]_{2} blocks comprising the structure and a negative Grüneisen parameter. Owing to these quasi-2D structural and dynamical features, we find that the mode can be utilized to realize unusual membrane effects, including a tunable negative thermal expansion (NTE) and a rare pressure-independent thermal softening of the bulk modulus. Detailed microscopic analysis shows that the NTE relies on strong intralayer Ti-O covalent bonding and weaker interlayer interactions, which is in contrast to conventional NTE mechanisms for perovskites, such as rigid-unit modes, structural transitions, and electronic or magnetic ordering. The general application of the quasi-2D lattice dynamics opens exciting avenues for the control of lattice dynamical and thermodynamic responses of other complex layered compounds through rational chemical substitution, as we show in A_{3}Zr_{2}O_{7} (A=Ca, Sr), and by heterostructuring.

Homogeneous Fluorine Doping toward Highly Conductive and Stable Li10GeP2S12 Solid Electrolyte for All-Solid-State Lithium Batteries.

The unique structure and exceptionally high lithium ion conductivity over 10 mS cm-1 of Li10GeP2S12 have gained extensive attention in all-solid-state lithium batteries. However, its poor resistivity to moisture and chemical/electrochemical incompatibility with lithium metal severely impede its practical application. Herein, a fluorine functionalized Li10GeP2S12 is synthesized by stannous fluoride doping and employed as a monolayer solid electrolyte to realize stable all-solid-state lithium batteries. The atomic-scale mechanism underlying the impact of fluorine doping on both moisture and electrochemical stability of Li10GeP2S12 is revealed by density functional theory calculations. Fluorine surface doping significantly reduces surface hydrophilicity by electronic regulation, thereby retarding the hydrolysis reaction of Li10GeP2S12. After exposed to a relative humidity of 35%-40% for 20 min, the ionic conductivity of Li9.98Ge0.99Sn0.01P2S11.98F0.02 maintains as high as 2.21 mS cm-1, nearly one order of magnitude higher than that of Li10GeP2S12 with 0.31 mS cm-1. Meanwhile, bulk doping of highly electronegative fluorine promotes the formation of lithium vacancies in the Li10GeP2S12 system, thus allowing stable lithium plating/stripping in Li | Li symmetric batteries, boosting a critical current density reaching 2.1 mA cm-2. The LiCoO2 | lithium all-solid-state batteries display improved cycling stability and rate capability, showing 80.1% retention after 600 cycles at 1C.

Accurate Simulation for 2D Lubricating Materials in Realistic Environments: From Classical to Quantum Mechanical Methods.

2D materials such as graphene, MoS2, and hexagonal BN are the most advanced solid lubricating materials with superior friction and anti-wear performance. However, as a typical surface phenomenon, the lubricating properties of 2D materials are largely dependent on the surrounding environment, such as temperature, stress, humidity, oxygen, and other environmental substances. Given the technical challenges in experiment for real-time and in situ detection of microscopic environment-material interaction, recent years have witnessed the acceleration of computational research on the lubrication behavior of 2D materials in realistic environments. This study reviews the up-to-date computational studies for the effect of environmental factors on the lubrication performance of 2D materials, summarizes the theoretical methods in lubrication from classical to quantum-mechanics ones, and emphasizes the importance of quantum method in revealing the lubrication mechanism at atomic and electronic level. An effective simulation method based on ab initio molecular dynamics is also proposed to try to provide more ways to accurately reveal the friction mechanisms and reliably guide the lubricating material design. On the basis of current development, future prospects, and challenges for the simulation and modeling in lubrication with realistic environment are outlined.

A brain cell atlas integrating single-cell transcriptomes across human brain regions.

While single-cell technologies have greatly advanced our comprehension of human brain cell types and functions, studies including large numbers of donors and multiple brain regions are needed to extend our understanding of brain cell heterogeneity. Integrating atlas-level single-cell data presents a chance to reveal rare cell types and cellular heterogeneity across brain regions. Here we present the Brain Cell Atlas, a comprehensive reference atlas of brain cells, by assembling single-cell data from 70 human and 103 mouse studies of the brain throughout major developmental stages across brain regions, covering over 26.3 million cells or nuclei from both healthy and diseased tissues. Using machine-learning based algorithms, the Brain Cell Atlas provides a consensus cell type annotation, and it showcases the identification of putative neural progenitor cells and a cell subpopulation of PCDH9high microglia in the human brain. We demonstrate the gene regulatory difference of PCDH9high microglia between hippocampus and prefrontal cortex and elucidate the cell-cell communication network. The Brain Cell Atlas presents an atlas-level integrative resource for comparing brain cells in different environments and conditions within the Human Cell Atlas.

Eight In. Wafer-Scale Epitaxial Monolayer MoS2.

Large-scale, high-quality, and uniform monolayer molybdenum disulfide (MoS2) films are crucial for their applications in next-generation electronics and optoelectronics. Epitaxy is a mainstream technique for achieving high-quality MoS2 films and is demonstrated at a wafer scale up to 4-in. In this study, the epitaxial growth of 8-in. wafer-scale highly oriented monolayer MoS2 on sapphire is reported as with excellent spatial homogeneity, using a specially designed vertical chemical vapor deposition (VCVD) system. Field effect transistors (FETs) based on the as-grown 8-in. wafer-scale monolayer MoS2 film are fabricated and exhibit high performances, with an average mobility and an on/off ratio of 53.5 cm2 V-1 s-1 and 107, respectively. In addition, batch fabrication of logic devices and 11-stage ring oscillators are also demonstrated, showcasing excellent electrical functions. This work may pave the way of MoS2 in practical industry-scale applications.

Lanthanide-doped MoS2 with enhanced oxygen reduction activity and biperiodic chemical trends.

Molybdenum disulfide has broad applications in catalysis, optoelectronics, and solid lubrication, where lanthanide (Ln) doping can be used to tune its physicochemical properties. The reduction of oxygen is an electrochemical process important in determining fuel cell efficiency, or a possible environmental-degradation mechanism for nanodevices and coatings consisting of Ln-doped MoS2. Here, by combining density-functional theory calculations and current-potential polarization curve simulations, we show that the dopant-induced high oxygen reduction activity at Ln-MoS2/water interfaces scales as a biperiodic function of Ln type. A defect-state pairing mechanism, which selectively stabilizes the hydroxyl and hydroperoxyl adsorbates on Ln-MoS2, is proposed for the activity enhancement, and the biperiodic chemical trend in activity is found originating from the similar trends in intraatomic 4f-5d6s orbital hybridization and interatomic Ln-S bonding. A generic orbital-chemistry mechanism is described for explaining the simultaneous biperiodic trends observed in many electronic, thermodynamic, and kinetic properties.

Single-cell RNA sequencing uncovers dynamic roadmap and cell-cell communication during buffalo spermatogenesis.

Spermatogenesis carries the task of precise intergenerational transmission of genetic information from the paternal genome and involves complex developmental processes regulated by the testicular microenvironment. Studies performed mainly in mouse models have established the theoretical basis for spermatogenesis, yet the wide interspecies differences preclude direct translation of the findings, and farm animal studies are progressing slowly. More than 32,000 cells from prepubertal (3-month-old) and pubertal (24-month-old) buffalo testes were analyzed by using single-cell RNA sequencing (scRNA-seq), and dynamic gene expression roadmaps of germ and somatic cell development were generated. In addition to identifying the dynamic processes of sequential cell fate transitions, the global cell-cell communication essential to maintain regular spermatogenesis in the buffalo testicular microenvironment was uncovered. The findings provide the theoretical basis for establishing buffalo germline stem cells in vitro or culturing organoids and facilitating the expansion of superior livestock breeding.

Fluorinated Li10 GeP2 S12 Enables Stable All-Solid-State Lithium Batteries.

The instability of Li10 GeP2 S12 toward moisture and that toward lithium metal are two challenges for the application in all-solid-state lithium batteries. In this work, Li10 GeP2 S12 is fluorinated to form a LiF-coated core-shell solid electrolyte LiF@Li10 GeP2 S12 . Density-functional theory calculations confirm the hydrolysis mechanism of Li10 GeP2 S12 solid electrolyte, including H2 O adsorption on Li atoms of Li10 GeP2 S12 and the subsequent PS4 3- dissociation affected by hydrogen bond. The hydrophobic LiF shell can reduce the adsorption site, thus resulting in superior moisture stability when exposing in 30% relative humidity air. Moreover, with LiF shell, Li10 GeP2 S12 shows one order lower electronic conductivity, which can significantly suppress lithium dendrite growth and reduce the side reaction between Li10 GeP2 S12 and lithium, realizing three times higher critical current density to 3 mA cm-2 . The assembled LiNbO3 @LiCoO2 /LiF@Li10 GeP2 S12 /Li battery exhibits an initial discharge capacity of 101.0 mAh g-1 with a capacity retention of 94.8% after 1000 cycles at 1 C.

Copper-catalyzed multiple oxidation and cycloaddition of aryl-alkyl ketones (alcohols) for the synthesis of 4-acyl- and 4-diketo-1,2,3-triazoles.

A Cu/TEMPO-catalyzed tandem multiple oxidative dehydrogenation and cycloaddition has been developed, which affords 4-acyl-1,2,3-triazoles and 4-diketo-1,2,3-triazoles from readily-available aryl-alkyl ketones (or alcohols) and different organic azides. Moreover, the reaction used environmentally friendly dimethyl carbonate (DMC) as the solvent and air as the oxidant, and H2O was the only by-product, so it provides a green and practical synthetic method for 1,2,3-triazoles.

Hepatic glycerolipid metabolism is critical to the egg laying rate of Guangxi Ma chickens.

Yolk formation in liver is an important process for egg production in hens. The correlations between egg laying rate decline and liver function changes in Guangxi Ma chickens remain unclear. In this study, a total of 21,750 genes and 76,288 transcripts were identified in the RNA expression profiles isolated from liver tissues of 5 groups of Guangxi Ma chickens divided according to the age and egg laying rate. Numerous differential genes (DEGs) were identified after pairwise comparison among samples, and time series analysis categorization (age-related factors) revealed that down-regulated DEGs with aging were predominantly involved in lipid transportation and metabolic processes in the low egg laying rate groups. Notably, functional enrichment analysis confirmed that DGAT2, LIPG, PNPLA2, LPL, CEL, LIPC, DGKD, AGPAT2, AGPAT1 and AGPAT3 were highlighted as hub genes in glycerolipid metabolism pathway, which may be an essential non-age related factors of egg laying rate by regulating the synthesis of triacylglycerol (TAG) in liver. Finally, we categorized DEGs in Guangxi Ma chickens with different egg laying rate caused by age-related factors and found that DEGs with different expression patterns performing different biological functions. The analysis of DEGs with lower egg laying rate caused by non-age related factors and showed that the transportation of TAG was suppressed. Furthermore, critical genes and pathways involved in the synthesis of TAG in livers were identified, which dynamically regulated the formation of yolk precursors. Our results expanded the knowledge of the molecular mechanisms of the yolk precursor synthesis in chicken livers. The results will be helpful to explore the factors that affect egg laying rate from the perspective of yolk synthesis and provide a theoretical basis for improving the egg production of Guangxi Ma chickens.

Experimental Investigation of Phase Equilibria in the Co-Ta-Si Ternary System.

In this work, two isothermal sections of the Co-Ta-Si ternary system at 900 °C and 1100 °C are constructed in the whole composition range via phase equilibrium determination with the help of electron probe microanalysis (EPMA) and X-ray diffraction (XRD) techniques. Firstly, several reported ternary phases G (Co16Ta6Si7), G″ (Co4TaSi3), E (CoTaSi), L (Co3Ta2Si) and V (Co4Ta4Si7) are all re-confirmed again. The G″ phase is found to be a kind of high-temperature compound, which is unstable at less than 1100 °C. Additionally, the L phase with a large composition range (Co32-62Ta26-36Si10-30) crystallizes with a hexagonal crystal structure (space group: P63/mmc, C14), which is the same as that of the binary high-temperature λ1-Co2Ta phase. It can be reasonably speculated that the ternary L phase results from the stabilization toward low-temperature of the binary λ1-Co2Ta through adding Si. Secondly, the binary CoTa2 and SiTa2 phases are found to form a continuous solid solution phase (Co, Si)Ta2 with a body-centered tetragonal structure. Thirdly, the elemental Si shows a large solid solubility for Co-Ta binary compounds while the Ta and Co are hardly dissolved in Co-Si and Ta-Si binary phases, respectively.

Comparative Proteomic Analyses of Poorly Motile Swamp Buffalo Spermatozoa Reveal Low Energy Metabolism and Deficiencies in Motility-Related Proteins.

The acquisition of mammalian sperm motility is a main indicator of epididymal sperm maturation and helps ensure fertilization. Poor sperm motility will prevent sperm cells from reaching the fertilization site, resulting in fertilization failure. To investigate the proteomic profiling of normal and poorly motile buffalo spermatozoa, a strategy applying liquid chromatography tandem mass spectrometry combined with tandem mass targeting was used. As a result, 145 differentially expressed proteins (DEPs) were identified in poorly motile spermatozoa (fold change > 1.5), including 52 upregulated and 93 downregulated proteins. The upregulated DEPs were mainly involved in morphogenesis and regulation of cell differentiation. The downregulated DEPs were involved with transport, oxidation-reduction, sperm motility, regulation of cAMP metabolism and regulation of DNA methylation. The mRNA and protein levels of PRM1 and AKAP3 were lower in poorly motile spermatozoa, while the expressions of SDC2, TEKT3 and IDH1 were not correlated with motility, indicating that their protein changes were affected by transcription or translation. Such changes in the expression of these proteins suggest that the formation of poorly motile buffalo spermatozoa reflects a low efficiency of energy metabolism, decreases in sperm protamine proteins, deficiencies in motility-related proteins, and variations in tail structural proteins. Such proteins could be biomarkers of poorly motile spermatozoa. These results illustrate some of the molecular mechanisms associated with poorly motile spermatozoa and provide clues for finding molecular markers of these pathways.

Quercetin Alleviates Endoplasmic Reticulum Stress-Induced Apoptosis in Buffalo Ovarian Granulosa Cells.

Endoplasmic reticulum (ER) stress plays a crucial role in granulosa cell (GCs) apoptosis, which is the main cause of follicular atresia. Quercetin (QC), a plant-derived flavonoid, has antioxidant, anti-inflammatory, and other biological properties. However, whether QC can alleviate the effects of ER stress on buffalo GCs remains unknown. In this study, we constructed an ER stress model in buffalo GCs by using tunicamycin (TM) and pre-treated with QC to explore the effect of QC on cells under ER stress. Apoptosis was detected by Annexin fluorescein 5 isothiocyanate (V-FITC), and the expressions of mRNA and related proteins involved in ER stress and apoptosis were detected via real-time polymerase chain reaction and Western blot. The results revealed that ER stress can cause apoptosis in GCs, whereas QC pre-treatment can prevent apoptosis caused by ER stress. After pre-treatment with QC, the expression levels of ER stress-related genes and proteins significantly decreased, pro-apoptotic genes were significantly down-regulated, and anti-apoptotic genes were significantly up-regulated. Furthermore, the results of Chop gene overexpression suggested that QC alleviated ER stress via the PERK/CHOP signaling pathway. In this study, we preliminarily elucidated that QC alleviates ER stress-induced apoptosis in buffalo GCs, and the results suggest a novel strategy for delaying follicular atresia by inhibiting GCs apoptosis.

Genomic Identification, Evolution, and Expression Analysis of Bromodomain Genes Family in Buffalo.

Bromodomain (BRD) is an evolutionarily conserved protein-protein interaction module that is critical in gene regulation, cellular homeostasis, and epigenetics. This study aimed to conduct an identification, evolution, and expression analysis of the BRD gene family in the swamp buffalo (Bubalus bubalis). A total of 101 BRD protein sequences deduced from 22 BRD genes were found in the buffalo genome. The BRD proteins were classified into six groups based on phylogenetic relationships, conserved motifs, and conserved domains. The BRD genes were irregularly distributed in 13 chromosomes. Collinearity analysis revealed 20 BRD gene pairs that had remarkable homologous relationships between the buffalo and cattle, although no tandem or segmental duplication event was found in the buffalo BRD genes. Comparative transcriptomics using a 10x sequencing platform analysis showed that 22 BRD genes were identified in the Sertoli cells (SCs) at different developmental stages of buffalo. Further, the mRNA expression levels of bromodomain and the extraterminal (BET) family in SCs at the pubertal stage were higher than that at the prepubertal stage of buffalo. However, the SMARCA2, PHIP, BRD9, and TAF1 genes exhibited the opposite trend. The maturation process of SCs may be regulated by the BRD family members expressed differentially in SCs at different developmental stages of buffalo. In summary, our findings provide an understanding of the evolutionary, structural, and functional properties of the buffalo BRD family members, and further characterize the function of the BRD family in the maturation of SCs. It also provides a theoretical basis for further understanding in the future of the mechanism of SCs regulating spermatogenesis.

Superhydrophilic Fe3+ Doped TiO2 Films with Long-Lasting Antifogging Performance.

Based on the superhydrophilicity of titanium dioxide (TiO2) after ultraviolet irradiation, it has a high potential in the application of antifogging. However, a durable superhydrophilic state and a broader photoresponse range are necessary. Considering the enhancement of the photoresponse of TiO2, doping is an effective method to prolong the superhydrophilic state. In this paper, a Fe3+ doped TiO2 film with long-lasting superhydrophilicity and antifogging is prepared by sol-gel method. The experiment and density-functional theory (DFT) calculations are performed to investigate the antifogging performance and the underlying microscopic mechanism of Fe3+ doped TiO2. Antifogging tests demonstrate that 1.0 mol % Fe3+ doping leads to durable antifogging performance which lasts 60 days. The DFT calculations reveal that the Fe3+ doping can both increase the photolysis ability of TiO2 under sunlight exposure and enhance the stability of the hydroxyl adsorbate on TiO2 surface, which are the main reasons for a long-lasting superhydrophilicity of TiO2 after sunlight exposure.