Xi’an University

BACKGROUND: High-throughput transcriptome sequencing (RNA-seq) technology promises to discover novel protein-coding and non-coding transcripts, particularly the identification of long non-coding RNAs (lncRNAs) from de novo sequencing data. This requires tools that are not restricted by prior gene annotations, genomic sequences and high-quality sequencing. RESULTS: We present an alignment-free tool called PLEK (predictor of long non-coding RNAs and messenger RNAs based on an improved k-mer scheme), which uses a computational pipeline based on an improved k-mer scheme and a support vector machine (SVM) algorithm to distinguish lncRNAs from messenger RNAs (mRNAs), in the absence of genomic sequences or annotations. The performance of PLEK was evaluated on well-annotated mRNA and lncRNA transcripts. 10-fold cross-validation tests on human RefSeq mRNAs and GENCODE lncRNAs indicated that our tool could achieve accuracy of up to 95.6%. We demonstrated the utility of PLEK on transcripts from other vertebrates using the model built from human datasets. PLEK attained >90% accuracy on most of these datasets. PLEK also performed well using a simulated dataset and two real de novo assembled transcriptome datasets (sequenced by PacBio and 454 platforms) with relatively high indel sequencing errors. In addition, PLEK is approximately eightfold faster than a newly developed alignment-free tool, named Coding-Non-Coding Index (CNCI), and 244 times faster than the most popular alignment-based tool, Coding Potential Calculator (CPC), in a single-threading running manner. CONCLUSIONS: PLEK is an efficient alignment-free computational tool to distinguish lncRNAs from mRNAs in RNA-seq transcriptomes of species lacking reference genomes. PLEK is especially suitable for PacBio or 454 sequencing data and large-scale transcriptome data. Its open-source software can be freely downloaded from https://sourceforge.net/projects/plek/files/.

Abstract The increasing demand for a whiter smile has resulted in an increased popularity for tooth whitening procedures. The most classic hydrogen peroxide-based whitening agents are effective, but can lead to enamel demineralization, gingival irritation, or cytotoxicity. Furthermore, these techniques are excessively time-consuming. Here, we report a nondestructive, harmless and convenient tooth whitening strategy based on a piezo-catalysis effect realized by replacement of abrasives traditionally used in toothpaste with piezoelectric particles. Degradation of organic dyes via piezo-catalysis of BaTiO 3 (BTO) nanoparticles was performed under ultrasonic vibration to simulate daily tooth brushing. Teeth stained with black tea, blueberry juice, wine or a combination thereof can be notably whitened by the poled BTO turbid liquid after vibration for 3 h. A similar treatment using unpoled or cubic BTO show negligible tooth whitening effect. Furthermore, the BTO nanoparticle-based piezo-catalysis tooth whitening procedure exhibits remarkably less damage to both enamel and biological cells.

Abstract In this study, mechanical vibration is used for hydrogen generation and decomposition of dye molecules, with the help of BiFeO 3 (BFO) square nanosheets. A high hydrogen production rate of ≈124.1 μmol g −1 is achieved under mechanical vibration (100 W) for 1 h at the resonant frequency of the BFO nanosheets. The decomposition ratio of Rhodamine B dye reaches up to ≈94.1 % after mechanical vibration of the BFO catalyst for 50 min. The vibration‐induced catalysis of the BFO square nanosheets may be attributed to the piezocatalytic properties of BFO and the high specific surface area of the nanosheets. The uncompensated piezoelectric charges on the surfaces of BFO nanosheets induced by mechanical vibration result in a built‐in electric field across the nanosheets. Unlike a photocatalyst for water splitting, which requires a proper band edge position for hydrogen evolution, such a requirement is not needed in piezocatalytic water splitting, where the band tilting under the induced piezoelectric field will make the conduction band of BFO more negative than the H 2 /H 2 O redox potential (0 V) for hydrogen generation.

Abstract As a high‐capacity layered cathode material, Li[Ni 0.8 Co 0.1 Mn 0.1 ]O 2 (NCM811) has been one of the most felicitous candidates for utilization in the next generation of high‐energy lithium ion batteries (LIBs). Notwithstanding its superiority, there are some issues concerning its cyclability, rate capability, and thermal stability that need to be settled prior to its further practical application. It is believed that upon cycling, chemical, mechanical, and electrochemical stability of the cathode–electrolyte interface plays a key role in resolving these issues. Therefore, all the extensive efforts directed so far toward the optimization of NCM811 electrochemical performance are by some means in connection with the cathode–electrolyte interface. Herein, unique structural and electrochemical characteristics of NCM811 together with in‐depth understanding of its underlying bulk/surface degradation mechanism through cycling are reviewed. More importantly, for the first time, all compatible approaches thus far adopted to perfect the performance of NCM811 are exclusively and scrupulously addressed. Lastly, the most reasonable resolutions to accomplish a robust cathode–electrolyte interface, and consequently impeccable NCM811, along with proposed future research directions are presented.

Periodic road crack monitoring is an essential procedure for effective pavement management. Highly efficient and accurate crack measurements are key research topics in both academia and industry. Automatic methods gradually replaced traditional manual surveys for more reliable evaluation outputs and better efficiency, whereas the devices are not available to all functional classes of pavements and different departments considering the high cost versus the limited budget. Recently, the widespread use of smartphones and digital cameras made it possible to collect pavement surface crack images at an affordable price in easier ways. However, the qualities of these crack images are diversely influenced by the noises from pavement background, roadways, and so forth. Thus, traditional methods usually fail to extract accurate crack information from pavement images. Therefore, this research proposes a state-of-the-art pixelwise crack detection architecture called CrackU-net, which is featured by its utilization of advanced deep convolutional neural network technology. CrackU-net achieved pixelwise crack detection through convolution, pooling, transpose convolution, and concatenation operations, forming the “U”-shaped model architecture. The model is trained and validated by 3,000 pavement crack images, in which 2,400 for training and 600 for validating, using the Adam algorithm. CrackU-net has the performance of loss = 0.025, accuracy = 0.9901, precision = 0.9856, recall = 0.9798, and F-measure = 0.9842 with learning rate of 10−2. Meanwhile, the false-positive crack detection problem is avoided in CrackU-net. Therefore, CrackU-net outperforms both traditional approaches and fully convolutional network (FCN) and U-net for pixelwise crack detections.

Boron-containing polymers have many applications resulting from their prominent properties. Organoboron species with reversible B-O bonds have been successfully employed for the fabrication of various self-healing/healable and reprocessable polymers. However, the application of the polymers containing boronic ester or boroxine linkages is limited because of their instability to water. Herein, we report the hydrolytic stability and dynamic covalent chemistry of the nitrogen-coordinating cyclic boronic diester (NCB) linkages, and a new class of vitrimers based on NCB linkages is developed through the chemical reactions of reactive hydrogen with isocyanate. Thermodynamic and kinetic studies demonstrated that NCB linkages exhibit enhanced water and heat resistance, whereas the exchange reactions between NCB linkages can take place upon heating without any catalyst. The model compounds of NCBC-X1 and NCBC-X2 containing a urethane group and urea group, respectively, also showed higher hydrolytic stability compared to that of conventional boronic esters. Polyurethane vitrimers and poly(urea-urethane) vitrimers based on NCB linkages exhibited excellent solvent resistance and mechanical properties like general thermosets, which can be repaired, reprocessed, and recycled via the transesterification of NCB linkages upon heating. Especially, vitrimers based on NCB linkages presented improved stability to water and heat compared to those through conventional boronic esters because of the existence of N → B internal coordination. We anticipate that this work will provide a new strategy for designing the next generation of sustainable materials.

Abstract Electrochemical carbon monoxide reduction is a promising strategy for the production of value-added multicarbon compounds, albeit yielding diverse products with low selectivities and Faradaic efficiencies. Here, copper single atoms anchored to Ti 3 C 2 T x MXene nanosheets are firstly demonstrated as effective and robust catalysts for electrochemical carbon monoxide reduction, achieving an ultrahigh selectivity of 98% for the formation of multicarbon products. Particularly, it exhibits a high Faradaic efficiency of 71% towards ethylene at −0.7 V versus the reversible hydrogen electrode, superior to the previously reported copper-based catalysts. Besides, it shows a stable activity during the 68-h electrolysis. Theoretical simulations reveal that atomically dispersed Cu–O 3 sites favor the C–C coupling of carbon monoxide molecules to generate the key *CO-CHO species, and then induce the decreased free energy barrier of the potential-determining step, thus accounting for the high activity and selectivity of copper single atoms for carbon monoxide reduction.

Two-dimensional (2D) materials have attracted great attention mainly due to their unique physical properties and ability to fulfill the demands of future nanoscale devices. By performing high-throughput first-principles calculations combined with a semiempirical van der Waals dispersion correction, we have screened 73 direct- and 183 indirect-gap 2D nonmagnetic semiconductors from nearly 1000 monolayers according to the criteria for thermodynamic, mechanical, dynamic, and thermal stabilities and conductivity type. We present the calculated lattice constants, formation energy, Young's modulus, Poisson's ratio, shear modulus, anisotropic effective mass, band structure, band gap, ionization energy, electron affinity, and simulated scanning tunnel microscopy for each candidate meeting our criteria. The resulting 2D semiconductor database (2DSdb) can be accessed via the Web site https://materialsdb.cn/2dsdb/index.html. The 2DSdb provides an ideal platform for computational modeling and design of new 2D semiconductors and heterostructures in photocatalysis, nanoscale devices, and other applications. Further, a linear fitting model was proposed to evaluate band gap, ionization energy, and electron affinity of 2D semiconductors from the density functional theory (DFT) calculated data as initial input. This model can be as precise as hybrid DFT but with much lower computational cost.

Abstract Fuel cells are considered as a promising alternative to the existing traditional energy systems towards a sustainable future. Nevertheless, the synthesis of efficient and robust platinum (Pt) based catalysts remains a challenge for practical applications. In this work, we present a simple and scalable molten‐salt synthesis method for producing a low‐platinum (Pt) nanoalloy implanted in metal–nitrogen–graphene. The as‐prepared low‐Pt alloyed graphene exhibits a high oxygen reduction activity of 1.29 A mg Pt −1 and excellent durability over 30 000 potential cycles. The catalyst nanoarchitecture of graphene encased Pt nanoalloy provides a robust capability against nanoparticle migration and corrosion due to a strong metal–support interaction. Similarly, advanced characterization and theoretical calculations show that the multiple active sites in platinum alloyed graphene synergistically account for the improved oxygen reduction. This work not only provides an efficient and robust low‐Pt catalyst but also a facile design idea and scalable preparation technique for integrated catalysts to achieve more profound applications in fuel cells and beyond.

Abstract Heterostructure construction is an efficient method for reinforcing K + storage of transition metal selenides. The spontaneously developed internal electric fields give a strong boost to charge transport and significantly reduce the activation energy. Nevertheless, perfection of the interfacial region based on the energy level gradient and lattice matching degree is still a great challenge. Herein, rich vacancies and ultrafine CoSe 2 –FeSe 2 heterojunctions with semicoherent phase boundary are simultaneously obtained, which possess unique electronic structures and abundant active sites. When employed as anodes for potassium‐ion batteries (PIBs), CoSe 2 –FeSe 2 @C composites display a reversible potassium storage of 401.1 mAh g −1 at 100 mA g −1 and even 275 mAh g −1 at 2 A g −1 . Theoretical calculation also reveals that the potassium‐ion diffusion can be dramatically promoted by the controllable CoSe 2 –FeSe 2 heterojunction.

Abstract The electrochemical reduction of N 2 to NH 3 is emerging as a promising alternative for sustainable and distributed production of NH 3 . However, the development has been impeded by difficulties in N 2 adsorption, protonation of *NN, and inhibition of competing hydrogen evolution. To address the issues, we design a catalyst with diatomic Pd‐Cu sites on N‐doped carbon by modulation of single‐atom Pd sites with Cu. The introduction of Cu not only shifts the partial density of states of Pd toward the Fermi level but also promotes the d‐2π* coupling between Pd and adsorbed N 2 , leading to enhanced chemisorption and activated protonation of N 2 , and suppressed hydrogen evolution. As a result, the catalyst achieves a high Faradaic efficiency of 24.8±0.8 % and a desirable NH 3 yield rate of 69.2±2.5 μg h −1 mg cat. −1 , far outperforming the individual single‐atom Pd catalyst. This work paves a pathway of engineering single‐atom‐based electrocatalysts for enhanced ammonia electrosynthesis.

Abstract ZnS has great potentials as an anode for lithium storage because of its high theoretical capacity and resource abundance; however, the large volume expansion accompanied with structural collapse and low conductivity of ZnS cause severe capacity fading and inferior rate capability during lithium storage. Herein, 0D-2D ZnS nanodots/Ti 3 C 2 T x MXene hybrids are prepared by anchoring ZnS nanodots on Ti 3 C 2 T x MXene nanosheets through coordination modulation between MXene and MOF precursor (ZIF-8) followed with sulfidation. The MXene substrate coupled with the ZnS nanodots can synergistically accommodate volume variation of ZnS over charge–discharge to realize stable cyclability. As revealed by XPS characterizations and DFT calculations, the strong interfacial interaction between ZnS nanodots and MXene nanosheets can boost fast electron/lithium-ion transfer to achieve excellent electrochemical activity and kinetics for lithium storage. Thereby, the as-prepared ZnS nanodots/MXene hybrid exhibits a high capacity of 726.8 mAh g −1 at 30 mA g −1 , superior cyclic stability (462.8 mAh g −1 after 1000 cycles at 0.5 A g −1 ), and excellent rate performance. The present results provide new insights into the understanding of the lithium storage mechanism of ZnS and the revealing of the effects of interfacial interaction on lithium storage performance enhancement.

Abstract Quantum networks promise to provide the infrastructure for many disruptive applications, such as efficient long-distance quantum communication and distributed quantum computing 1,2 . Central to these networks is the ability to distribute entanglement between distant nodes using photonic channels. Initially developed for quantum teleportation 3,4 and loophole-free tests of Bell’s inequality 5,6 , recently, entanglement distribution has also been achieved over telecom fibres and analysed retrospectively 7,8 . Yet, to fully use entanglement over long-distance quantum network links it is mandatory to know it is available at the nodes before the entangled state decays. Here we demonstrate heralded entanglement between two independently trapped single rubidium atoms generated over fibre links with a length up to 33 km. For this, we generate atom–photon entanglement in two nodes located in buildings 400 m line-of-sight apart and to overcome high-attenuation losses in the fibres convert the photons to telecom wavelength using polarization-preserving quantum frequency conversion 9 . The long fibres guide the photons to a Bell-state measurement setup in which a successful photonic projection measurement heralds the entanglement of the atoms 10 . Our results show the feasibility of entanglement distribution over telecom fibre links useful, for example, for device-independent quantum key distribution 11–13 and quantum repeater protocols. The presented work represents an important step towards the realization of large-scale quantum network links.

BACKGROUND: Prevalences of Alzheimer disease (AD) and vascular dementia (VaD) in China reportedly differ from those in Western countries. OBJECTIVE: To estimate prevalence of AD and VaD in 4 regions of China. DESIGN: Cross-sectional, population-based prevalence survey with a stratified, multistage cluster sampling design. SETTING: Rural (n = 99) and urbanized (n = 71) communities of Beijing, Xian, Shanghai, and Chengdu. PARTICIPANTS: A sample of 34 807 community residents (94% of those eligible) 55 years or older. MAIN OUTCOME MEASURES: Participants were screened with the Chinese Mini-Mental State Examination. Those who screened positive (n = 3950) underwent a standardized diagnostic workup. Screening sensitivity was assessed in a 3.3% random sample (n = 1008 of the 30 857 who passed the screening). Diagnoses of AD and VaD were made according to National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer Disease and Related Disorders Association and National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences criteria, respectively. Final diagnoses were made after a 6-month confirmation interval. RESULTS: We identified 732 AD cases and 295 VaD cases. Prevalence in persons 65 years or older was 3.5% (95% confidence interval, 3.0%-3.9%) for AD and 1.1% (95% confidence interval, 0.9%-1.1%) for VaD. After post hoc correction for negative screening errors, prevalence increased to 4.8% for AD and remained at 1.1% for VaD. CONCLUSION: Prevalence of dementia subtypes in China is comparable with that in Western countries.

Abstract The development of highly efficient non‐precious metal electrocatalysts for the oxygen evolution reaction (OER) in low‐grade or saline water is currently of great importance for the large‐scale production of hydrogen. In this study, by using an electrochemical activation pretreatment, metal oxy(hydroxide) nanosheet structures derived from self‐supported nickel–iron phosphide and nitride nanoarrays grown on Ni foam are successfully fabricated for OER catalysis in saline water. It is demonstrated that the different NiOOH and NiOOH@FeOOH (NiOOH grown on FeOOH) structures are generated from nickel–iron nitride and phosphide, respectively, after electrochemical activation. In particular, the NiOOH@FeOOH heteroarchitecture shows outstanding electrocatalytic performance with an ultralow overpotential of 292 mV to drive the current density of 500 mA cm −2 . An unconventional dual‐sites mechanism (UDSM) is proposed to address the OER process on NiOOH@FeOOH and show that the FeOOH underlayer plays a critical role regarding the enhanced OER activity of NiOOH. The new possible UDSM involving two reaction sites presents a different understanding of the OER process on multi‐OH layer complexes, which is expected to guide the design of heteroarchitecture electrocatalysts.

Abstract The transformation from traditional manufacturing to intelligent manufacturing intrigues the profound and lasting effect on the future manufacturing worldwide. Industry 4.0 was proposed for advancing manufacturing to realize short product life cycles and extreme mass customization in a cost‐efficient way. As the heart of Industry 4.0, smart factory integrates physical technologies and cyber technologies and makes the involved technologies more complex and precise in order to improve performance, quality, controllability, management, and transparency of manufacturing processes. So far, leading manufacturers have begun the journey toward implementing smart factory. However, most firms still lack insight into the challenges and resources for implementing smart factory. As such, this paper identifies the requirements and key challenges, investigates available new technologies, reviews existing studies that have been done for smart factory, and further provides guidance for manufacturers to implementing smart factory in the context of Industry 4.0.

Heterostructure engineering is one of the most promising modification strategies toward improving sluggish kinetics for the anode of sodium ion batteries (SIBs). Herein, we report a systemic investigation on the different types of heterostructure interfaces’ effects of discharging products (Na2O, Na2S, Na2Se) on the rate performance. First-principle calculations reveal that the Na2S/Na2Se interface possesses the lowest diffusion energy barrier (0.39 eV) of Na among three kinds of interface structures (Na2O/Na2S, Na2O/Na2Se, and Na2S/Na2Se) due to its smallest recorded interface deformation, similar electronegativity, and lattice constant. The experimental evidence confirms that the metal sulfide/metal selenide (SnS/SnSe2) hierarchical anode exhibits outstanding rate performance, where the normalized capacity at 10 A g–1 compared to 0.1 A g–1 is 45.6%. The proposed design strategy in this work is helpful to design high rate performance anodes for advanced battery systems.

Aqueous zinc‐ion batteries (AZIBs) are regarded as promising electrochemical energy storage devices owing to its low cost, intrinsic safety, abundant zinc reserves, and ideal specific capacity. Compared with other cathode materials, manganese dioxide with high voltage, environmental protection, and high theoretical specific capacity receives considerable attention. However, the problems of structural instability, manganese dissolution, and poor electrical conductivity make the exploration of high‐performance manganese dioxide still a great challenge and impede its practical applications. Besides, zinc storage mechanisms involved are complex and somewhat controversial. To address these issues, tremendous efforts, such as surface engineering, heteroatoms doping, defect engineering, electrolyte modification, and some advanced characterization technologies, have been devoted to improving its electrochemical performance and illustrating zinc storage mechanism. In this review, we particularly focus on the classification of manganese dioxide based on crystal structures, zinc ions storage mechanisms, the existing challenges, and corresponding optimization strategies as well as structure–performance relationship. In the final section, the application perspectives of manganese oxide cathode materials in AZIBs are prospected.

Abstract The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO 3 ) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d 33 of HA/BaTiO 3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO 3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO 3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO 3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO 3 piezoelectric ceramics.

An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction (ORR) is crucial for energy conversion and storage devices. However, most of the high-efficiency ORR catalysis was reported in alkaline conditions. Herein, we demonstrated the preparation of atomically dispersed Fe-Zn pairs anchored on porous N-doped carbon frameworks (Fe-Zn-SA/NC), which works efficiently as ORR catalyst in the whole pH range. It achieves high half-wave potentials of 0.78, 0.85 and 0.72 V in 0.1 M HClO4, 0.1 M KOH and 0.1 M phosphate buffer saline (PBS) solutions, respectively, as well as respectable stability. The performances are even comparable to Pt/C. Furthermore, when assembled into a Zn-air battery, the high power density of 167.2 mWcm−2 and 120 h durability reveal the feasibility of Fe-Zn-SA/NC in real energy-related devices. Theoretical calculations demonstrate that the superior catalytic activity of Fe-Zn-SA/NC can be contributed to the lower energy barriers of ORR at the Fe-Zn-N6 centers. This work demonstrates the potential of Fe-Zn pairs as alternatives to the Pt catalysts for efficient catalytic ORR and provides new insights of dual-atom catalysts for other energy conversion related catalytic reactions.