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A broad scope of quinazolin-4(3H)-ones or benzothiadiazine 1,1-dioxides was obtained via a transition-metal free and convenient method. This approach involving KHSO4 promoted cyclization and dehydration between diverse functionalized 2-aminobenzamides or 2-aminobenzenesulfonamides and N, N-dimethylformamide derivatives. The protocol offers moderate to excellent yields (45%-93%) under mild condition in a short of reaction time of 6 hours. The use of an environment-friendly and less expensive catalyst KHSO4 also makes this protocol more attractive. [ABSTRACT FROM AUTHOR]

Mpox virus (MPXV) is a zoonotic DNA virus that caused human Mpox, leading to the 2022 global outbreak. MPXV infections can cause a number of clinical syndromes, which increases public health threats. Therefore, it is necessary to develop an effective and reliable method for infection prevention and control of epidemic. Here, a Cas12a-based direct detection assay for MPXV DNA is established without the need for amplification. By targeting the envelope protein gene (B6R) of MPXV, four CRISPR RNAs (crRNAs) are designed. When MPXV DNA is introduced, every Cas12a/crRNA complex can target a different site of the same MPXV gene. Concomitantly, the trans-cleavage activity of Cas12a is triggered to cleave the DNA reporter probes, releasing a fluorescence signal. Due to the application of multiple crRNAs, the amount of active Cas12a increases. Thus, more DNA reporter probes are cleaved. As a consequence, the detection signals are accumulated, which improves the limit of detection (LOD) and the detection speed. The LOD of the multiple crRNA system can be improved to ~ 0.16 pM, which is a decrease of the LOD by approximately ~ 27 times compared with the individual crRNA reactions. Furthermore, using multiple crRNAs increases the specificity of the assay. Given the outstanding performance, this assay has great potential for Mpox diagnosis. [ABSTRACT FROM AUTHOR]

This study investigated the effect of Pt doping on the microstructure, mechanical and tribological property of the CrN coating. Results showed that this CrN coating exhibited a loose columnar texture and a rough surface with a high Ra value of 3.07 ± 0.035 nm. A prominent coherent growth within the grain appeared in this coating, which provides strong bond strength of coating texture resulting in a high H/E ratio of 0.083. This CrN coating showed an unidirection scratch fracture, but also possessed good wear resistance with a smooth wear track. Pt doping induced a nearly single preferential growth of (200) plane, and resulted in a dense columnar texture and a smooth surface. The Ra value was 2.71 ± 0.285 nm for the CrN–Pt 9.55 coating, and decreased to 1.04 ± 0.14 nm for the CrN–Pt 17.73 coating. However, Pt atoms greatly blocked the coherent growth within the grain, and further degraded the bond strength of coating texture. The CrN–Pt 9.55 coating showed serious multidirection scratch fracture, but also experienced severe wear accompanied with numerous cracks and adhesive debris. In contrast, the hindrance effect and mechanical degradation were further strengthened with the increase of Pt doping content. This CrN–Pt 17.73 coating suffered from most severe fracture damage and debris adhesion during the scratch and sliding wear tests. [ABSTRACT FROM AUTHOR]

MORF-RELATED GENE702 (OsMRG702) regulates flowering time genes in rice, but how it controls transcription is not well known. Here, we found that OsMRGBP can directly interact with OsMRG702. Both Osmrg702 and Osmrgbp mutants show the delayed flowering phenotype with the reduction in the transcription of multiple key flowering time genes, including Ehd1 and RFT1. Chromatin immunoprecipitation study showed that both OsMRG702 and OsMRGBP bind to the Ehd1 and RFT1 loci and the absence of either OsMRG702 or OsMRGBP leads to a decrease of H4K5 acetylation at these loci, indicating OsMRG702 and OsMRGBP cooperatively together to promote the H4K5 acetylation. In addition, whilst Ghd7 are upregulated in both Osmrg702 and Osmrgbp mutants, only OsMRG702 binds to the loci, together with the global increased and Ghd7 locus-specific increased H4K5ac levels in Osmrg702 mutants, suggesting an additional negative effect of OsMRG702 on H4K5 acetylation. In summary, OsMRG702 controls flowering gene regulation by altering H4 acetylation in rice; it works either together with OsMRGBP to enhance transcription by promoting H4 acetylation or with other unknown mechanisms to dampen transcription by preventing H4 acetylation. [ABSTRACT FROM AUTHOR]

Non-isothermal hot embossing has great potential in the mass production of glass micro optical components due to the relatively short heating-cooling cycle time. However, warpage was induced by the temperature gradient inside the glass replica during hot embossing, resulting in a deteriorated optical performance. Therefore, it is non-trivial to investigate the effects of process parameters on warping and filling behaviors of glass in non-isothermal hot embossing. Firstly, a high-quality microhole was fabricated on monocrystalline silicon carbide (SiC) mold by focused ion beam (FIB) lithography. By using a novel home-made gravity-assisted hot embossing machine, the geometric information (i.e., warpage and microstructures) on SiC mold was transferred into the surface of N-BK7 glass replica. The experimental results indicate that high embossing temperature enables not only the minimization of warpage but also the enhancement of microstructure replication accuracy. Furthermore, increasing embossing force enhances filling capacity but increases warpage amplitude. Interestingly, fast heating/cooling rates and short embossing time enable a small warpage as well as a high embossing efficiency. By optimizing the process parameters, especially the embossing temperature, a small warpage amplitude of 3 μm and a high transfer ratio of 99.11% were achieved, which can meet the high requirement of precision optical components. [ABSTRACT FROM AUTHOR]

Structural ceramics are potential mold materials for hot embossing, due to their superior mechanical strength as well as low thermal expansion coefficient. However, the service time of molds, especially those in high-temperature hot embossing, strongly depends on their oxidation resistance. As a result, the oxidation behaviors of various ceramics (e.g., SiC, ZrO2, AlN, Al2O3, Si3N4 and WC) were investigated by conducting cyclic oxidation experiments in this study. Mass changes of ceramic samples thermal treated under different temperatures were measured by thermogravimeter (TGA) and precision electronic balance. The structural and chemical compositions of ceramic samples were detected by X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDXS). The surface morphology of the samples was characterized by scanning electron microscopy (SEM), and the surface roughness of the samples was measured by white light interferometry. The mechanical properties of the samples were evaluated by a microhardness tester and nanoindentation instrument. It is noted that Al2O3 shows negligible oxidation within 1000 °C. ZrO2 maintains a decent surface roughness of below 32 nm and a stable hardness within 1000 °C. SiC has the highest hardness at high temperatures, and its surface roughness increases notably above 800 °C. The surface roughness of Si3N4 and AlN soars between 600 °C and 800 °C. The surface finish of WC is significantly deteriorated above 600 °C. Therefore, the appropriate embossing temperature of Al2O3 ceramics is below 1000 °C, that of ZrO2 ceramics is between 800 °C and 1000 °C, that of SiC ceramics is below 800 °C, that of Si3N4 and AlN ceramics is between 600 °C and 800 °C, and that of WC ceramics below 600 °C. [ABSTRACT FROM AUTHOR]

This paper evaluates the impact of China's fiscal decentralization reform, namely the "Province-Managing-County" (PMC) fiscal reform, on local governments' regional development strategy using county-level data in China covering 2000 to 2013. Surprisingly, after implementing the PMC fiscal reform, local governments will adjust their strategy of supporting zombie firms and attracting new firms, indicating that fiscal decentralization has changed the regional development strategies of local governments. We perform a difference-in-differences (DID) analysis and find that the PMC fiscal reform materially induces an average rise of 0.131 in newly added firms, an average decline of 0.383 in zombie firms, and no significant change in other firms. There is a pronounced substitution effect between zombie firms and newly added firms. We also find evidence supporting this argument: the government's subsidy, tax treatment, and financial support. Our study provides empirical evidence that local governments' regional development strategies can be affected by fiscal decentralization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel strategy of bimetallic MOFs for enhanced PAAS is designed. • The enhanced PAAS is ascribed to the improved mass transfer in MOFs. • Sustainable NH 3 production rate achieves 77.5 μmol g−1·min−1 in 36 h or ∼ 30 cycles. • Hypothetical zero-carbon ammonia plant exhibits notable competitiveness. Plasma-assisted ammonia synthesis (PAAS) can produce ammonia using highly energetic, electronically excited nitrogen and Hydrogen radicals at low temperatures and atmospheric pressure, which has been regarded as a prospective alternative to the Haber − Bosch process. PAAS can exclusively use renewable power (solar, wind, etc.) to achieve green, decentralized and efficient ammonia synthesis. However, current catalysts for PAAS are suffering from low efficiency, poor stability and cyclability. Herein, we demonstrate a one-step hydrothermal synthesis of Ni-Co bimetallic metal–organic frameworks (MOFs) for PAAS. Attributed to the amplified gas transport capability and bimetallic coupling, the Ni-Co-MOF exhibits significantly improved PAAS performance: 88.21 μmol g−1·min−1, above 30 % increase over 5 wt% Ni/Al 2 O 3. The high stability of Ni-Co-MOF under the harsh electric field enables its durable performance (36 h) and excellent cyclability (24 cycles). Finally, to determine the viability of PAAS for industrial applications, we construct a hypothetical zero-carbon ammonia plant using only renewable energy sources, and the outcomes indicate that PAAS has significant competitiveness for future ammonia production. [ABSTRACT FROM AUTHOR]

• A novel stepwise Li-mediated electrochemical nitrogen reduction (Li-NRR) was developed. • The decomposition of solid-electrolyte interphase was revealed by decoupling the continuous Li-NRR. • Zn exhibited fastest electron transfer and Li+ diffusion, demonstrating best Li-NRR performance. • The proportion of active lithium was demonstrated to influence the Faraday efficiency. • LiCl generated in protonation process was found to enhance the system stability and facilitate the recycling of lithium. The lithium-mediated electrochemical nitrogen reduction reaction (Li-NRR) is a sustainable route for green NH 3 synthesis. It accelerates the N 2 reduction by reacting the inert N ≡ N with active Li metal. However, the study on the mechanism of the Li-NRR process remains limited. Herein, a novel stepwise Li-NRR system is established to separately optimize the major steps of Li-NRR: lithium-ion reduction, lithium nitridation, and Li 3 N protonation. It is revealed that during the Solid Electrolyte Interface (SEI) decomposition, the carbon chains in organic species become shorter, and Li x BF y is converted to LiF, which is similar to the continuous Li-NRR. Contrary to the continuous Li-NRR, the O/C ratio decreases as the SEI decomposes due to the absence of ethanol. Commercial Cu, Ni, and Zn are employed as cathodes in the experiments at various currents. The highest Faraday efficiency of 33.2 % and ammonia yield rate of 1404.5 μg h−1 cm−2 are achieved on Zn electrode owing to its superior electron transfer and enhanced Li+ diffusion than those of Cu and Ni. The current has also been found to affect Faraday efficiency through the portion of active lithium in coulomb efficiency experiments. Moreover, the LiCl generated in protonation process is found to facilitate lithium cycling. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the effects of process parameters and feature size on filling behavior of polymethyl methacrylate (PMMA) in rapid hot embossing. The filling behavior of PMMA was characterized by analyzing the surface topography of microlenses that were formed on the surface of PMMA after a series of hot embossing experiments, which were conducted by using a universal testing machine that is equipped with a rapid heating module. Experimental results indicated that increasing embossing temperature, embossing force, maintain force and embossing time led to higher average heights of microlenses, and thus improved the filling capacity of PMMA. Furthermore, embossing temperature has the most significant enhancement effect. Whereas, soaking time and demolding temperature shew very slight influence on the filling height of microlens. Therefore, cancelling soaking treatment and increasing demolding temperature are efficient strategies for shortening the cycle time of non-isothermal hot embossing without weakening the filling capacity of PMMA. Moreover, enlarging microhole diameter results in the increase of curvature radius and average height of microlens. Finally, a 5 × 5 microlens array was hot embossed on the PMMA substrate by using a 5 × 5 microhole array SiC mold. It is found that microlens at the center has the maximum height, while microlenses away from the center of PMMA substrate have smaller heights, which is attributed to the decreased contact pressure along the radial direction. [ABSTRACT FROM AUTHOR]

Contactless hot embossing has been demonstrated to possess the potential for cost‐effective production and precise mounting concepts in fabricating glass microlenses and microlens arrays due to the reduced difficulty of mold fabrication and the possibility of obtaining self‐aligned assemblies. This study aims to provide experimental evidence for understanding the forming mechanism of glass microlenses and microlens arrays in the contactless hot embossing process. The effects of process parameters, diameter and position of the micro‐holes, hole diameter, and pitch of the micro‐hole array mold on the filling deformation of glass in contactless hot embossing were comprehensively investigated. It is found that placing the micro‐hole farther away from the mold center renders decrease in both filling height and tip curvature but increase in the eccentricity of the embossed glass microlens. As a result, the formed glass microlens array shows a nonuniform distribution of filling height and tip curvature. Furthermore, reducing the pitch of micro‐hole array mold can significantly improve the uniformity of formed microlens array. Based on these experimental results, the forming mechanism of microlenses and microlens arrays in contactless hot embossing process is summarized. Finally, a glass microlens array with decent uniformity in the center area was hot embossed by using a SiC micro‐hole array mold. [ABSTRACT FROM AUTHOR]

Introduction: The objective of this study was to report our experience of angioplasty with paclitaxel-coated balloon (PCB) versus common balloon (CB) for the treatment of repeated failing vascular access. Methods: Retrospective, single-center analysis consisting of 88 patients treated with percutaneous transluminal angioplasty in the period from October 2020 through December 2021. Patients were divided into two groups according to the type of treatment as PCB (n = 41) and CB (n = 47). We analyzed target lesion primary patency and vascular access primary patency for 6 months and the rate of complications. Results: There was no significant difference in the target lesion primary patency which was similar for 6 months between the two groups (PCB group vs. CB group at 1, 3, and 6 months; 95.12 vs. 89.36% (p = 0.55), 75.61 versus 74.47% (p = 0.90), 53.66% versus 63.83% (p = 0.33), respectively). Similarly, vascular access primary patency in the PCB group and CB group was 90.24 and 89.36% (p = 0.83), respectively, at 1 month, 65.85 and 68.09% (p = 0.82), respectively, at 3 months, 39.02 and 53.19% (p = 0.18), respectively, at 6 months. There were no major complications after endovascular treatment. Conclusion: Compared to CB angioplasty, PCB angioplasty has no short-term patency benefit in the treatment of vascular access repeated stenosis. [ABSTRACT FROM AUTHOR]

In this study, TiB 2 –TiC–Al 2 O 3 gradient composite ceramic tool materials reinforced by VC/Cr 3 C 2 additives were prepared through vacuum hot-press sintering. The effects of gradient combination, thickness ratio and sintering process (sintering temperature and soaking time) on the mechanical properties and microstructures of the composites were investigated. The results showed that the high surface compressive stress produced by the adequate gradient combination and thickness ratios refined the grains and increased the crack growth path. By comparison, the sintering temperature and soaking time influenced the grain size and porosity. In addition, the effects of VC/Cr 3 C 2 on the grain size were analysed, and it was found that VC/Cr 3 C 2 inhibited TiC dissolution and accelerated Al 2 O 3 re-precipitation, which in turn refined the TiC grains and coarsened the Al 2 O 3 grains. Consequently, crack deflection and intergranular fracture occurred around the TiC grains, whereas trans -granular fracture occurred inside the TiB 2 and Al 2 O 3 grains because rapid Al 2 O 3 precipitation facilitated TiB 2 grain growth. The optimum mechanical properties were hardness of 23.59 GPa, fracture toughness of 7.45 MPa m1/2, and flexural strength of 764.11 MPa. [ABSTRACT FROM AUTHOR]

The TiB 2 -TiC-Al 2 O 3 multi-dimensional gradient ceramic tool (MDGCT), whose composition varied in two directions, were designed and fabricated via hot-pressed vacuum sintering. The cutting performance, including cutting force, cutting temperature and chip morphology, and failure mechanisms of MDGCT with different orientation angles in intermittent turning of SKD11 hardened steel were investigated in comparison with the homogeneous commercial ceramic tool CC650 at different depths of cut and cutting speeds. And the distribution of thermal residual stress of MDGCT was investigated employing FEM analysis. Results showed that the multi-dimensional gradient ceramic tool with orientation angle of 15 degree (TT3A15) had the optimal comprehensive cutting performance. The main failure mechanisms of CC650 tool were chipping and fracture caused by crack propagation, while the crack propagation was effectively inhibited in the TT3A15 tool, and its failure mechanism was chipping at the tool nose. The contribution of multi-dimensional gradient structure of TT3A15 tool to the increasing residual compressive stress of minor cutting edge, the favorable anti-crack capacity of flank face and the heterogeneity of physical and mechanical properties of rake face were responsible for its optimal cutting performance. • The multi-dimensional gradient ceramic tool (MDGCT) were fabricated via hot-pressed vacuum sintering and employed in intermittent turning of SKD11 hardened steel. Results indicated that the cutting force, cutting temperature and chip morphology of TT3A15 are better than those of other cutting tools. • FEM analysis of MDGCT showed that the residual compressive stress increasing along minor cutting edge of MDGCT could effectively inhibit the propagation of crack. • The multi-dimensional gradient structure had a positive impact on its cutting performance. Firstly, the thermal conductivity of rake face increasing along major cutting edge is conductive to rapid conduction of cutting heat. Secondly, the facture roughness of MDGCT gradually increases in the direction of crack propagation at flank face, contributing to inhibiting crack propagation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile co-precipitation method yields efficient Co-doped graphdiyne catalysts. • Co-doped graphdiyne enhances NH 3 decomposition (100% conversion at 550 ℃). • NH x dehydrogenation (x = 3) is the rate-determining step on Co-doped graphdiyne. Manufacturing hydrogen from ammonia decomposition is an efficient and promising approach for hydrogen utilization. However, its scalable application is significantly impeded by the requirements of precious metal ruthenium (Ru) as catalysts. Herein, we report a type of Co-doped graphdiyne catalyst for catalytically decomposing ammonia (NH 3) to generate H 2. The metal-doped graphdiyne catalysts were synthesized facilely using co-precipitation approach. The resultant composite catalysts significantly enhanced the reactivity and stability of ammonia decomposition. The Co-doped graphdiyne catalyst achieved nearly complete decomposition of ammonia at 550 ℃, and the conversion rate remained stable over 18 h of continuous reaction. The adsorption and decomposition of ammonia by Co-doped graphdiyne was studied by density functional theory (DFT) calculations. Nitrogen binding strength was used as a descriptor to elucidate the catalyst's activity and reaction kinetics, further supported by the reaction energy barrier. Our study highlights the tremendous potential of metal-doped graphdiyne catalysts for facile hydrogen production via NH 3 decomposition, enabling safe and scalable hydrogen utilization. [ABSTRACT FROM AUTHOR]

Chemical looping ammonia synthesis (CLAS) is promising to achieve decentralized ammonia synthesis under ambient pressure. Here, we develop a highly selective composite nitrogen carrier for efficient CLAS based on transition metals (TMs=Co, Ni, Fe) decorated chromium nitride (CrN). Systematic studies indicate that the pristine CrN is extremely inert: only 4.5% lattice nitrogen can be consumed in reacting with H 2 (700 °C, 1 bar). Upon loading cobalt, the composite nitrogen carrier achieves lattice nitrogen conversion of 50.7% and ammonia selectivity up to 98.1%. Furthermore, Co-CrN exhibits excellent CLAS performance, attaining an average ammonia production rate of 466.1 μmol g−1 h−1 in 12 chemical loopings, which is ∼10 times that of the pristine CrN. Theoretical calculations reveal that the nitrogen vacancies generated in hydrogenation play a crucial role as activation centers for N 2 fixation through a Mars–van Krevelen mechanism. This work provides a novel strategy to optimize nitrogen carriers for enhanced CLAS. [Display omitted] • CLAS mediated by Cr-based nitrogen carriers was reported for the first time. • Novel strategy in designing synergistic nitrogen carriers with dual active sites. • Controlled conversion rate of lattice-N by 50.7% and high NH 3 selectivity at 98.1%. • Sustainable NH 3 production rate achieved 466.1 μmol g−1 h−1 in more than 12 cycles. • Reduced reaction energy barrier was verified in DFT calculations. [ABSTRACT FROM AUTHOR]

Chemical looping ammonia production (CLAP) technology provides additional freedom for the optimization of operating conditions via the strategy of stepwise reactions, which is promising to achieve green ammonia synthesis under mild conditions. Mn-based nitrogen carriers are ideal redox materials by virtue of their moderate thermodynamic properties and abundant crystalline phases, but their performance of hydrogenation in CLAP is still limited by the low reactivity. Herein, a series of Ni-Mn-N composite nitrogen carriers with different Ni/Mn ratios were prepared, and the effect of Ni doping on the performance of NH 3 production was investigated at atmospheric pressure. The nitrogen carriers modified with low level of Ni (<20 wt%) showed high activity and selectivity of hydrogenation, and the effective conversion of lattice nitrogen in 80Mn20Ni-N reached 36.1% at 750 °C, which was 15.7% higher than the undoped 100Mn-N. The introduction of low level of Ni can simultaneously enhance the bulk migration and interfacial reaction of lattice nitrogen and achieve the optimal kinetic matching between the both processes, thus promoting the activity and selectivity of lattice nitrogen converted to NH 3. This study presents new insights into the design of composite nitrogen carriers to enhance ammonia production in CLAP. • Ni-Mn-N composite nitrogen carriers were developed for chemical looping ammonia production. • The activity and selectivity of hydrogenation can be promoted by low level of Ni doping. • Ni dopants enhanced the bulk migration and interfacial reaction of lattice N. • Low level of Ni can achieve the optimal kinetic matching between the both processes. [ABSTRACT FROM AUTHOR]

The performance of existing frequency-domain channel estimation and equalization algorithms for faster-than-Nyquist (FTN) signaling is seriously hampered with the noise enhancement phenomenon that results from their inverse or pseudo-inverse operations. Through simulations, we show that the linear precoding can effectively mitigate the above-mentioned noise enhancement phenomenon. At first, a low complexity precoding-based channel estimation (PCE) algorithm is proposed for FTN signaling over frequency-selective fading channels. In contrast with most existing frequency-domain channel estimation algorithms, the proposed PCE algorithm has much better mean square error performance, and the performance improvement enlarges with the increase of signal to noise ratio. Furthermore, a joint channel estimation and precoding (JCEP) algorithm is proposed to perform data detection for FTN signaling over frequency-selective fading channels. On the one hand, compared with the existing frequency-domain channel estimation and equalization algorithms, the JCEP algorithm greatly reduces the complexity of signal processing at receivers since it performs the linear precoding processing at transmitters. On the other hand, even with estimated channel state information (CSI), the proposed JCEP algorithm can approach the bit error rate (BER) performance of the Nyquist signaling for all the modulation types adopted in digital video broadcasting-satellite-second generation extension (DVB-S2X). More precisely, the BER performance degradation with perfect and estimated CSI is 0.06 dB and 0.07 dB respectively when the time acceleration parameter equals to 0.7 and the rolling factor is 0.45. [ABSTRACT FROM AUTHOR]

Spalling (Slabbing) is a typical failure phenomenon, which often occurs after excavation of rectangular tunnel. It has a serious impact on the construction, support and stability of the tunnel. To investigate the characteristics and mechanism of spalling-failure in rectangular tunnel, a series of tests were carried out on granite rectangular tunnel with different height-to-width ratios (H/Ws) (1/2, 3/4, 1/1, 4/3 and 2/1) by using true triaxial system. The whole process of spalling was monitored and recorded by wireless micro camera. According to the test results, the failure mode and failure characteristics of the sidewall spalling were summarized, and the influence of the H/Ws of the rectangular hole on the failure characteristics and stability of the tunnel were discussed in detail. The test results indicate that when the vertical principal stress is the maximum principal stress, the sidewalls of the specimens experience spalling failure. When the spalling occurs, the crack occurs at the shoulder corner of the sidewall and propagates along the axis, resulting in the spalling damage gradually developing from the local area to the whole sidewall along the axis, and forming the thin rock slab parallel to the sidewall. In addition, rectangular tunnels with different H/Ws clearly influence spalling failure. When the height was the same, the degree of spalling damage decreases with the decrease of its width. On the contrary, when the width was the same, the degree of spalling damage does not decrease with the increase in the height. When the height was equal to the width, the damage degree of the tunnel spalling is the largest, which seriously affects the safety of the tunnel. In the case of the same cross-section area of the tunnel, the stability of the tunnel can be improved by selecting the layout mode with the height greater than the width. It is necessary to strengthen the monitoring of the cracks at the shoulder corner of the tunnel, which can reduce the safety risk of the tunnel. These conclusions are helpful to the design of the tunnel, the prevention of spalling and the improvement of the stability of the tunnel. [ABSTRACT FROM AUTHOR]

The load–unload response ratio (LURR) theory was introduced to study the rockburst proneness of rock materials, and a rockburst proneness criterion was proposed in this project. First, ten rocks (including three types of granite, three types of sandstone, one kind of limestone, and three types of marble) were chosen on which to carry out the uniaxial step load–unload test, and then a calculation method for LURR at different load–unload points based on a data-fitting algorithm was presented. The LURR-strain curves of the ten rocks were divided into the decrease stage, the steady stage, and the increase stage, and the starting point of the increase stage was defined as the LURR S-R (start rise) point. Subsequently, the LURR difference method was put forward to determine the LURR S-R point scientifically. Finally, the relationship between the lag time ratio (the lag time ratio was defined as the ratio of the time from the LURR S-R point to the peak strength point to the time of the whole loading period) and the degree of rockburst proneness for ten rocks was investigated; the results show that there is an obvious correspondence between the lag time ratio and the degree of rockburst proneness. Then, a rockburst proneness criterion based on the lag time ratio index was proposed. In addition, the real-time pre-warning of rockburst proneness based on the dynamic lag time ratio index was also presented and analysed. [ABSTRACT FROM AUTHOR]

In the traditional interference channel (IC), each transmitter works in the mode of one-to-one. For serving more user terminals (UTs), a multiple-multicast network is proposed, in which there are multiple transmitters, and each transmitter works in the mode of one-to-many. Thus, each UT would suffer from both the intra-transmitter and inter-transmitter interference. Given the transmitting and receiving degrees of freedom, the desired signal would be more difficult to be separated from the numerous interference signals. For managing the interference, an interference subspace alignment (ISA) algorithm is proposed to decrease the dimension of the interference subspace. Different from the traditional iterative interference alignment (IA) algorithms, which iteratively calculate the precoding and receiving combining matrices to minimize the strength of interference, the ISA algorithm directly aligns the interference subspace spanned by the $T-N$ transmitters within that spanned by the residual $N$ transmitters, in which $T$ denotes the number of all the transmitters, and $N$ is the cardinality of the transmitter set used for IA. Now, the dimension of each UT's interference subspace is determined via $N$ transmitters ($N < T$). During the subspace alignment, we, respectively, construct the composite IC state matrices for the $T-N$ and $N$ transmitters, and the composite precoding vector, which lies in the null space of the composite IC matrices. Thus, all the precoding matrices can be obtained once. After the subspace alignment, each UT's receiving combining matrix can be designed to lie in the null space of the aligned interference subspace. According to the simulation results, the proposed ISA algorithm can effectively suppress the interference and improve the system sum rate compared with the traditional interference management algorithms. [ABSTRACT FROM AUTHOR]

• A brief introduction of single-molecule magnets (SMMs) and polyoxometalates (POMs). • The advantageous chemical and structural features of POM frameworks for the preparation of SMMs. • The systemic classification and survey of POMs-based SMMs. • The synthesis strategies and multifunctional properties for future application devices. Single-molecule magnets (SMMs) have attracted increasing attention in recent years due to the potentially applicable in high-density information storage and spintronic devices. There are now many high-performance SMMs that have been achieved by the use of organic ligands. Meanwhile, polyoxometalates (POMs) as inorganic multidentate ligands are toward prospective candidates for the fabrication of SMMs, owing to their oxygen-rich surfaces and various coordination geometries of the incorporated 3d- and 4f-ions. Notably, the bulky diamagnetic shell of POMs efficiently excludes dipole–dipole coupling between neighboring molecules, and the rigid frameworks offer the advantage for surface deposition and device applications. Hence, the wide variety of paramagnetic cations have been stabilized by POM ligands to establish SMMs, including mono-, di-, multi- and hetero-metal containing POMs. We herein systematically summarize the research progress achieved for POM-based SMMs reported in the last decade. The present review focuses on the design strategies for the construction of the SMMs referring to POM ligands and multifunctional properties of the POM-based SMMs for future application devices. This review provides a roadmap for the further exploration of compelling and challenging areas in POM-based SMMs. [ABSTRACT FROM AUTHOR]

A novel hot embossing process to fabricate the hierarchical macro/nano optical glass lens is innovatively proposed. [Display omitted] • A novel hot embossing strategy to fabricate the hierarchical macro/nano optical glass lens is innovatively proposed. • The hierarchical macro-/nano glass lens made by second hot embossing show good optical performance. • The deformation history and forming mechanism of hierarchical macro-/nano glass structures are revealed. Constructing nanostructured surfaces on the macro/micro-scale optical lens is of great importance in the improvement of light transmittance, reflection, and surface functionality of optical devices. In this paper, a flexible and novel material interface design and manufacturing method for hierarchical macro/nano optical glass lenses is proposed. To verify the feasibility of the presented manufacturing strategy, the deformation history and flow driving mechanism of multiscale structured surfaces during second hot embossing were studied by simulations and experiments. The results showed that solid-like glass preform exhibits a higher nanoscale deformation resistance and elastic recovery, which can reduce the distortion levels of the nanostructured surface. At small scales, molecular confinement greatly reduces the tectonic deformation of nanostructured surface at relatively low applied heat and pressure. However, beyond a specific thermal energy threshold, nanostructured convex surfaces are easily compressed into a smooth flattened surface. By collaborative control of embossing conditions, the nano-surface integrity of multiscale structured surface can be ensured during second hot embossing. Compared to the smooth macroscale optical lens, the hierarchical macro/nano glass lens exhibited better optical transmittance and antireflection properties. The proposed design and manufacturing strategy provides a facile and flexible solution for building the hierarchical macro/micro/nanostructure functional optics. [ABSTRACT FROM AUTHOR]

Highlights • DPIF of key substructures was applied to identify Acanthopanax TSs using MSAll and SWATH. • Thirty-three compounds were reported as potentially new compounds in genus Acanthopanax. • A malonyl-saponin was the first report in genus Acanthopanax. Abstract This paper focused on untargeted MSAll, also called MSE, and sequential window acquisition of all theoretical fragment-ion spectra (SWATH) fragmentations for comprehensive structural characterization of triterpene saponins (TSs) in leaves of Acanthopanax senticosus through ultra-high performance liquid chromatography electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF). [M+H]+, [M + NH 4 ]+ and [M + Na]+ precursor ions and the corresponding fragment ions were collected simultaneously in energy-resolved MSAll. SWATH fragmentation was applied as a comparable and complementary method for resolving co-eluting species. A workflow based on MSAll and SWATH fragmentations was constructed for comprehensive structural characterization and rapid discovery of TSs in leaves of A. senticosus. As a result, 89 TSs, along with 14 sapogenins, were unambiguously characterized or tentatively identified. Of these, 33 compounds were characterized as potentially new compounds, including the first report of malonyl-saponin in genus Acanthopanax. This study aimed to systematically analyze TSs in leaves of A. senticosus, and the results are significant for the utilization of A. senticosus leaves. [ABSTRACT FROM AUTHOR]

A considerable number of deep engineering cases show that strain rockbursts occur on both sidewalls of circular caverns and ultimately form a symmetrical V-shaped notch. To investigate the occurrence process and mechanism of strain rockbursts in deep circular cavern under high stresses, simulation experiments under four different three-dimensional (3D) stress conditions were conducted on cubic granite specimens with a prefabricated circular hole using the true-triaxial electro-hydraulic servo mutagenesis testing system. The rock bursting process was monitored on the sidewalls of the hole and recorded in real-time with a wireless microcamera. The results show that the entire rock bursting process on the sidewalls can be divided into four distinct periods for every 3D stress condition: calm period, pellet ejection period, rock fragment exfoliation period, and rock bursting period. Under the conditions that the vertical stress is constant and the horizontal radial stress is equal to the horizontal axial stress, the rockburst severity of the sidewalls clearly decreases with increasing horizontal stress. When the vertical stress is constant and the horizontal axial stress is low, the rockburst severity clearly decreases with the increase of horizontal radial stress. In contrast, when the horizontal axial stress is high, the rockburst severity becomes more serious with increasing horizontal radial stress. During the process of rock fracture and bursting, the damage zones on both sidewalls form two symmetrical V-shaped notches, and the line connecting the centres of the two V-shaped notches is perpendicular to the maximum principal stress direction. The symmetrical V-shaped failure modes on both sidewalls under the four stress conditions are in line with the statistical relationship of the far-field stress state and failure mode of a deep circular cavern without support (Martin et al. in Can Geotech J 36(1):136–151, 1999). [ABSTRACT FROM AUTHOR]

Abstract The effects of high strain rates and low confining pressures on the dynamic mechanical properties of sandstone were investigated experimentally with a modified triaxial split Hopkinson pressure bar (SHPB) system. For comparison, dynamic uniaxial compression tests of the sandstone were also conducted by using a conventional SHPB system. The confining pressures used in the dynamic triaxial compression tests are 5, 7.5, 10, 12.5 and 15 MPa, and the strain rate of these tests varied from approximately 40 s−1 to 160 s−1. The results show that the dynamic uniaxial and triaxial compressive strengths of the sandstone will linearly increase with the logarithm of the stain rate. Under approximately the same strain rate, the dynamic triaxial compressive strength will linearly increase with the confining pressure. Although the peak strain has no dependence on the confining pressure, it will generally increase with the strain rate. The secant modulus is independent of the strain rate and confining pressure. Three trend diagrams, which reflect the influences of strain rate or confining pressure on the dynamic mechanical properties of sandstone in the uniaxial and triaxial compression tests, are given, and the correlation between the failure modes of the sandstone specimens and the characteristics of the stress-strain curves is also analyzed. [ABSTRACT FROM AUTHOR]

Abstract Spalling and rockburst are two common failure modes in deep hard-rock tunnels and they exhibit a strong correlation. In this paper, the process of rockburst induced by spalling is investigated. The uniaxial compressive strength and rockburst tendency of red sandstone are measured. Four different initial stress conditions are set up, and cubic red sandstone samples with a prefabricated hole are tested by a true-triaxial test system. During the experimental process, the failure of the hole sidewall is monitored and recorded in real time by a micro-camera. The process of rockburst induced by spalling damage in deep hard-rock tunnels is reproduced, and the mechanism by which spalling damage on induces rockburst is revealed. In addition, the evolution process and failure characteristics of rockburst induced by spalling damage are analysed. The experimental results indicated that the red sandstone has a moderate rockburst tendency, and its rockburst process can be divided into four periods: the calm period, the small grain ejection & spalling damage period, the slab buckling & fragment ejection period and the violent ejection period. The mechanism of spalling damage on inducing rockburst is mainly embodied in two aspects: promoting large buckling deformations (providing energy for rockburst) and to weakening the strength of the rock mass (creating conditions for the suddenly release of energy). The effect of lateral stress on spalling damage and rockburst is more obvious than that of axial stress, and the severity of rockburst can be significantly reduced by increasing the lateral stress. The diameter of the hole has a strength size effect on the sidewall damage, producing a certain inhibitory effect on the spalling damage and rockburst. Smaller lateral stress corresponds with greater depths of the V-shaped notch and much smaller width-to-length ratios in the rock fragments. [ABSTRACT FROM AUTHOR]

Abstract In the past four years, transition metal vanadates have received booming attention as anode materials for lithium ion batteries (LIBs) due to their outstanding specific capacities, decent cycling performance and superior rate properties. Among them, Co 3 V 2 O 8 is the most reported species. However the cobalt is expensive, thus the replacement of cobalt would be a favorable route. So far, mixed vanadates have been rarely reported because of the remarkable difficulty in fabrication, among which cobalt/nickel mixed vanadates are the most attractive. In this work, a facile and green hydrothermal method with organic linker has been developed, to achieve modulated cobalt/nickel mixtures. It was corroborated by the X-ray diffraction (XRD) patterns and cyclic voltammetry (CV) profiles that single phase of cubic Co 3 V 2 O 8 crystal structures were formed. The mixed vanadates demonstrated ultrahigh reversible capacity of over ∼1800 mAh/g at the current density of 0.2 A/g after ∼200 cycles and superb rate capability of ∼600 mAh/g at 4 A/g. The enhanced electrochemical performances of the higher-nickel-ratio indicated their considerable potential as high-capacity anode materials in LIBs. Graphical abstract Image 1 Highlights • Cobalt/nickel mixed vanadates were obtained via one-step and green hydrothermal process. • The mixed vanadates maintain the cubic crystal of Co 3 V 2 O 8 with nickel doping. • Higher concentration of doped nickel induced uniform nanoparticles smaller than 100 nm. • CoNi 2 V 2 O 8 delivered reversible capacity of 1800 mAh/g at 0.2 A/g and 600 mAh/g at 4 A/g. [ABSTRACT FROM AUTHOR]

Nisin is a small cationic peptide composed of 34 amino acid residues, it exhibits a wide spectrum antimicrobial activity against Gram-positive bacteria, but nisin has the disadvantages of poor stability and short duration of antibacterial activity. In order to improve the stability of nisin during food processing and storage period, the gum arabic (GA) is used to get GA-nisin microparticles. The analysis of zeta potential, SEM and FT-IR were used to characterize the combination of GA and nisin, test the antibacterial activity on Staphylococcus aureus and Escherichia coli, the bactericidal effect of GA-nisin microparticles decreased within 24 h compare to free nisin, however, GA-nisin microparticles after 121 °C treatment for 10 min, the activity loss rate is less than free nisin and has better sustained antibacterial effect at 25 °C. The results shown GA-nisin microparticles have better high-temperature stability and sustained bactericidal ability than the free nisin. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) transition metal disulfides (TMDSs) have triggered worldwide research interest due to their weak interlayer van der Waals (vdW) interaction, low cost, chemical/thermal stability and excellent processability. Among them, MoS 2 and WS 2 are two typical chemicals widely investigated. Yet their individual poor conductivity and restacking property require combination with other conductive materials, like carbonaceous matrices, to obtain better performance in energy storage and conversion devices. The current state-of-the-art and the progress made over the past five years on the development of XS 2 -based composite films (X = Mo, W), many of which are self-standing and additive-free, is summarized here. The pivotal role of such films in batteries, supercapacitors and hydrogen production is highlighted. The challenges and opportunities for the future exploration of these 2D layered hybrids are also put forward and discussed. [ABSTRACT FROM AUTHOR]

Multiphase nanocomposites have drawn substantial attention due to their advanced functionality, including high thermal conductivity. Herein, theoretical models are developed based on modifications of the effective medium theory and then validated to predict the effective thermal conductivity (Keff) of three common multiphase nanocomposites: nanosheet/nanoparticle/polymer, nanotube/nanoparticle/polymer, and nanosheet/nanotube/polymer. Case studies showed that the predicted Keff agreed well with available experimental data, validating the developed models. Moreover, quantifiable material properties, like the thermal conductivity of nanofillers, the morphology of nanofillers, and the interfacial thermal resistance around nanofillers, were used to investigate their effects on the Keff of multiphase nanocomposites. This quantitative study not only can provide simplified strategy to predict the Keff for diverse multiphase nanocomposites, but it can also guide the design of multiphase nanocomposites with enhanced thermal conductivity. [ABSTRACT FROM AUTHOR]

Room-temperature sodium-ion batteries have attracted great attentions for large-scale energy storage applications in renewable energy. However, exploring suitable anode materials with high reversible capacity and cyclic stability is still a challenge. The VS4, with parallel quasi-1D chains structure of V4+(S22-)2, which provides large interchain distance of 5.83 Å and high capacity, has showed great potential for sodium storage. Here, the uniform cuboid-shaped VS4 nanoparticles are prepared as anode for sodium-ion batteries by the controllable of graphene oxide (GO)-template contents. It exhibits superb electrochemical performances of high-specific charge capacity (≈580 mAh·g-1 at 0.1 A·g-1), long-cycle-life (≈98% retain at 0.5 A·g-1 after 300 cycles), and high rates (up to 20 A·g-1). In addition, electrolytes are optimized to understand the sodium storage mechanism. It is thus demonstrated that the findings have great potentials for the applications in high-performance sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Electrical discharge machining (EDM) method is an innovative method for the fabrication of structured array surfaces on binderless tungsten carbide (WC) which is a typical embossing mold material, compared to traditional machining methods. To improve the convenience of electrode replacement and the fabrication efficiency of the structured array, a novel self‐assembly ball electrode is innovatively developed. The feasibility of machining binderless WC with a self‐assembly ball electrode was studied and its effect on profile deviation analyzed. Furthermore, the discharge condition's effect on surface roughness, material removal rate (MRR), and tool wear ratio (TWR) was investigated. The microstructure, phase structure, and element distribution of binderless WC caused by EDM were characterized by Raman spectroscopy, scanning electron microscopy, and energy dispersive x‐ray spectroscopy. The results indicated that the maximum profile deviation of the different random structured arrays was about 3.7 μm. The surface roughness of all structured arrays was below 1 μm. The maximum TWR was about 0.008 mm3/min. Besides, the binderless WC surface after EDM presented strong D and G carbon peaks, which means the precipitation and transformation of the WC phase during the discharge process. Finally, different kinds of self‐assembly ball electrodes are developed and used to fabricate the lens array structures on binderless WC. The fast fabrication of the micro‐lens array surfaces in different arrangements sheds some light on the design and manufacturing of other functional structured surfaces. [ABSTRACT FROM AUTHOR]

Effectively thermal conduction pathways are essential for the thermal conductivity of polymer-based composites. In this contribution, we proposed a facile and feasible strategy to improve the thermal conductivity of polymer composites through constructing a segregated structure and hybrid conductive network. Boron nitride (BN) and aluminium nitride (AlN) were mechanically wrapped upon ultrahigh-molecular-weight polyethylene (UHMWPE) granules and then high-pressure consolidated. Morphology observation revealed that in the typical segregated pathways, polyhedral AlNs were in tandem with adjacent BN plates. A significantly synergistic enhancement in the thermal conductivity was achieved by the hybrid conductive network. At the total filler content of 50 wt%, the BN/AlN/UHMWPE composite with a filler ratio of 6:1 showed the thermal conductivity of 7.1 Wm -1 K −1 , outperforming BN/UHMWPE and AlN/UHMWPE composites by 35.1% and 613%, respectively. Infrared thermal images further demonstrated that the composites with hybrid segregated structure had strongest capability to dissipate the heat against the counterparts with single segregated structure. Based on the percolation effect with an effective medium approach, the theoretical calculation suggested that AlN played a bridge role to interconnect the BN platelets in the segregated conductive pathways, leading to the formation of the more effective thermally conductive pathways. The obtained results offer valuable fundamentals to design and fabricate the highly thermal-conductive polymer composites as advanced thermal management materials. [ABSTRACT FROM AUTHOR]

The aim of the study was to develop an alternative capillary zone electrophoresis (CZE) for simultaneous determination of phillyrin (1), phillygenin (2), epipinoresinol-4-O-β-glucoside (3), pinoresinol-4-O-β-glucoside (4), lariciresinol (5), pinoresinol (6), isolariciresinol (7) and vladinol D (8) in Forsythia suspensa. The structural types of lignans 1-8 could be attributed to bisepoxylignans (1-4 and 6), monoepoxylignans (5 and 8) and cyclolignan (7). The major difficulties in the CZE separation of 1-8 could be summarization as the simultaneous presence of free lignans (1, 2 and 5-8) and lignan glucosides (3 and 4) and simultaneous occurrence of two pairs of isomers (3 and 4 as well as 5 and 7). Without the addition of β-CD and methanol, the resolution of these analytes was quite poor. However, in this study, compounds 1-8 were excellently separated from each other within 15 min under optimized conditions with a borax running buffer (40 mM borax, pH 10.30) containing 2 mM β-CD and 5% methanol (v/v) at the voltage of 20 kV, temperature of 35 °C and detection wavelength of 234 nm. Validation of the method included tests of linearity, precision, repeatability, stability and accuracy. In addition, the method offered inherent advantages such as lower analytical cost, no need of specific columns and use of small amounts of organic solvents and reagents. Finally, this green and economic CZE was successfully applied for the determination of these bioactive components 1-8 in F. suspensa fruits and its commercial extracts. [ABSTRACT FROM AUTHOR]

Cobalt vanadates have been demonstrated as superior anode candidates for lithium ion batteries (LIBs) owing to their unique advantages, such as superb specific capacity, low operating potential, and excellent cycling stability. Among the cobalt vanadates, Co 3 V 2 O 8 manifests tremendous potential of commercialization because of their controllable particle size and morphology. In this study, we readily synthesized both hollow and solid Co 3 V 2 O 8 micro-pencils and thoroughly compared their electrochemical properties. Employed as anode for LIBs, the hollow Co 3 V 2 O 8 exhibited much higher initial specific capacity than the solid ones (∼1200 mAhg −1 vs. ∼680 mAhg −1 ). When tested at 1000 mAg −1 , the hollow Co 3 V 2 O 8 displayed superior reversible capacity over the solid ones (∼650 mAhg −1 vs. ∼450 mAhg −1 after 300 cycles), benefiting from the hollow architecture. Moreover, the hollow micro-pencils showed better rate performance, with outstanding stability and capacity loss when higher current density was applied. The comparative study demonstrated the hollow Co 3 V 2 O 8 is more efficient than the solid ones for LIB anodes. Based on the comparison on pure micro-pencils, further approach (e.g. graphene coating) can be exploited for superior performance towards ultimate application in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

A type of multidimensional graded ceramic tool materials (MGTMs) was designed and fabricated by vacuum hot-pressing sintering technology. The microstructure and compositional distribution of tool simultaneously changed in two different directions. The tool-chip and tool-workpiece contact regions were designed to have high hardness, and metal phases Mo and Ni were added to produce a gradual increase in toughness from the outer layer to core layer. The effect of orientation angle, thickness ratio and sintering parameters on the mechanical properties and microstructure were investigated. The experimental results showed that the composites, sintered at 1700 °C for 15 min, with the orientation angle of 30° and a thickness ratio of 0.4, had the optimal comprehensive mechanical properties. In addition, the crack propagation paths were observed to analyze the toughening mechanisms for the multidimensional graded ceramic tool materials. It was found that there is a crack resistance behavior when the crack extended from the outer layer to transition layer. The effect of the angle between the crack and graded interface on crack propagation paths was also investigated and the results indicated that the small angle was favorable for the crack deflection when the cracks passed through the graded interface. The residual thermal stress contributed to the occurrence of the crack bridging and transgranular fracture inside the Al 2 O 3 grains, while the intergranular fracture and crack deflection were observed around the TiC grains. [ABSTRACT FROM AUTHOR]

In this paper, we propose a scheme that integrates quantum key distribution and private classical communication via continuous variables. The integrated scheme employs both quadratures of a weak coherent state, with encrypted bits encoded on the signs and Gaussian random numbers encoded on the values of the quadratures. The integration enables quantum and classical data to share the same physical and logical channel. Simulation results based on practical system parameters demonstrate that both classical communication and quantum communication can be implemented over distance of tens of kilometers, thus providing a potential solution for simultaneous transmission of quantum communication and classical communication. [ABSTRACT FROM AUTHOR]

Digital analysis is an effective single-molecule detection method and has attracted extensive attention in the field of bioassays. However, most digital assays require microchambers for signal compartmentalization. Herein, we developed a microchamber-free and enzyme-free digital assay by labeling paramagnetic beads directly with ultrabright fluorescent microspheres. In this assay, a DNA sandwich analysis was firstly performed on the bead to label a fluorescent microsphere. Then, the beads were loaded on the glass slide to form a monolayer film for signal readout. The whole analysis process does not require the participation of enzymes and the preparation of microchambers, which greatly simplifies the experimental steps and saves the costs. Furthermore, by introducing non-enzymatic hybridization chain reaction (HCR) and biotinylated DNA-conjugated gold nanoparticles (Au NPs-Bio), the capture efficiency and analytical sensitivity were improved. As a proof of concept, single-stranded DNA (ssDNA) of SARS-CoV-2 fragment was chosen as a model, and a detection limit of 1.5 fM was achieved. Spiked and recovery experiments on human serum and saliva samples validated the good performance of the proposed digital assay in real biological samples. The proposed assay provides a facile way of signal generation and readout for digital analysis. • A microchamber-free digital assay was developed. • A digital assay that does not require the involvement of enzymes was achieved. • The discrimination between positive and negative beads in digital assay was improved. • A facile way of signal generation and readout for digital analysis was proposed. [ABSTRACT FROM AUTHOR]

Failure patterns of coated carbide tool were investigated by high-speed face milling of the hardened steel SKD11. Tool failure surface morphology, cutting force and machined surface roughness were also analyzed to reveal the failure mechanisms. The results indicated that the dominant failure pattern of coated carbide tool was breakage. The primary mechanism of tool breakage was fatigue fracture. Under different cutting speeds, the distinctive morphologies of fatigue fracture were presented on the failure surfaces. At low cutting speeds, many fatigue sources were observed on the rake face. The distance between fatigue sources and tool nose was approximately two times of the depth of cut. With the increase of cutting speed, the fatigue striations and riven patterns were observed at the fracture surface. In addition, the fatigue steps and crack deflection were found under high cutting speeds. The main fracture mode was intergranular fracture at lower cutting speeds. However, it was transgranular fracture at higher cutting speeds. Furthermore, the irregular fracture surfaces at low cutting speeds and at high cutting speeds contribute to a larger cutting force increment compared with the medium cutting speeds. The increment of surface roughness in the initial and severe wear stages was lower than that in the steady wear stage, while the deviation of surface roughness was relatively large. [ABSTRACT FROM AUTHOR]

Compared with traditional grinding, hard turning with ceramic tools has lots of advantages such as lower cost, higher productivity, better machining accuracy, and elimination of cutting fluids. However, the catastrophic fracture of ceramic tool frequently occurs in turning of hardened steel. Hence, there is a need to recognize the evolution of machinability aspects (cutting forces and tool wear) in the whole turning process. An orthogonal experiment was designed to investigate the evolution of cutting forces and tool failure mechanisms in intermittent turning of hardened 20CrMnTi steel with AlO-TiC ceramic tool. The effects of cutting parameters on cutting forces were analyzed by Taguchi method and analysis of variance (ANOVA) during different tool wear stages. The results revealed that the influence of cutting parameters on cutting forces gradually declined with the increased tool wear, and the contribution of depth of cut on cutting forces gradually increased. The optimal cutting parameters of cutting forces were calculated for different wear stages. In addition, the fracture modes and mechanisms of tool under different cutting conditions were investigated. The fatigue striations and fatigue beaches were observed at the fracture surface. The propagation paths and mechanisms of fatigue cracks were analyzed under different cutting speeds. The results indicated that the fracture area of tool was mainly affected by mechanical stress, while the depth of crack propagation was determined by thermal stress. [ABSTRACT FROM AUTHOR]

A novel protocol for the synthesis of functionalized pyridines containing quaternary carbon centers through a metal-free catalytic intramolecular acylcyanation approach has been developed. Broad scope, versatility, and efficiency of the process was demonstrated. [ABSTRACT FROM AUTHOR]

Nucleotide excision repair (NER) protects genome stability by eliminating DNA helix distorting lesions, such as those induced by UV radiation. The addition and removal of ubiquitin, namely, ubiquitination and deubiquitination, have recently been demonstrated as general mechanisms to regulate protein functions. Accumulating evidence shows that several NER factors are subjected to extensive regulation by ubiquitination and deubiquitination. Thus, the balance between E3 ligases and deubiquitinating enzyme activities can dynamically alter the ubiquitin landscape at DNA damage sites, thereby regulating NER efficiency. Current knowledge about XPC ubiquitination by different ubiquitin E3 ligases highlights the importance of ubiquitin linkage types in regulating XPC binding and release from damaged DNA. Here, we discuss the emerging roles of deubiquitinating enzymes and their ubiquitin linkage specificities in NER. [ABSTRACT FROM AUTHOR]

A general distributed multi-antenna two-way relaying network with multiple relays is considered in this paper. We first obtain a tight lower bound of pairwise error probability (PEP) of a maximum likelihood detector for the general distributed linear dispersion code for a half-duplex amplify-and-forward two-way relaying network (TWRN) consisting of two sources with each having single antenna and $N$ relays with each having two antennas. Furthermore, by jointly considering signal precoding at the sources and signal processing at the relays, a general distributed concatenated recursive Alamouti-circulant space-time block code is proposed for the considered TWRNs. Our design ensures that the equivalent channel matrices at both source nodes are the so-called the recursive Alamouti-circulant matrices, with each block being a product of the two Alamouti channel matrices. Based on a lower–upper bound strategy and an induction method, asymptotic PEP formula is attained to show that given the optimal angle rotation matrix and the precoding matrix, the code can meet the lower bound of the diversity gain, as well as the maximum coding gain. In addition, the proposed rate one code turns to be effectively decodable. [ABSTRACT FROM AUTHOR]

Human epididymis protein 4 (HE4) is a highly sensitive and specific biomarker for diagnosing ovarian cancer. In this work, a new electrochemical aptasensor for rapid and sensitive detection of HE4 was constructed. Firstly, metal–organic framework/ketjen black (NH2-MIL-53(Al)/KB) composite with abundant amino groups and large specific surface area was prepared as signal amplifier to anchor gold nanoparticles (AuNPs). Subsequently, signal probe (SP) and a large amount of electroactive toluidine blue (Tb) were attached on AuNPs to form the tracer label, producing a distinct electrochemical detection signal. Moreover, Ni3(HITP)2 was modified by poly(diallyldimethylammonium chloride, PDDA) to obtain PDDA/Ni3(HITP)2, and then it was covered with deposited gold nanocrystals (DpAu) to form the sensing platform, which increased the electrical conductivity, specific surface area and the loading of triple-helix assembled probes (TAP). Target HE4 was bound to its aptamer in the outer layer of the TAP, leaving a separate capture probe (CP) on the electrode surface that can bind with the tracer label. The proposed aptasensor for HE4 detection showed a wide linear range from 1 to 10 nM with a detection limit of 0.41 fM. In addition, the aptasensor has good selectivity, stability and reproducibility. More importantly, this method showed satisfactory results in clinical serum sample analysis compared with ELISA, possessing application prospects in ovarian cancer diagnosis. [ABSTRACT FROM AUTHOR]

A novel asymmetric catalytic approach for the construction of enantioenriched functionalized 1,2-dihydropyridines and pyridine derivatives incorporating adjacent quaternary and tertiary stereocenters has been reported. This process involved a metal-free catalytic asymmetric allylic alkylation and a stereospecifically nonoxidative aromatization approach for the desired chiral molecules. [ABSTRACT FROM AUTHOR]

The mechanical performance of materials is greatly affected and could be tuned by artificial defects, especially for amorphous alloys. In present work, specially designed holes are created for bulk metallic glass and apparent mechanical performance improvement is obtained when compared with the intact ones. The fracture characterization discovers that the inner wall of the artificial hole has a blocking effect to shear bands (SBs), leading to an apparent enhancement of mechanical property. Our results demonstrate that the blocking effect of SBs induced by the designing artificial hole may provide some new sights on the plastic deformation mechanism of metallic glasses rather than the improved plasticity itself. [ABSTRACT FROM AUTHOR]

Microdeep drawing has great potential in microsystem technologies, electron industries, new energy, etc. Microsquare cups with internal side length of 1 mm were formed in this study. The blank material was pure copper C1100 with a thickness of 50 μm which was annealed in vacuum condition at 573 and 723 K for 1 h, respectively. The experiments were conducted with an electronic universal testing machine. Three kinds of different lubrication conditions and blank holder force (BHF) were used, and the experimental velocity was 0.05 mm/s. The results showed that a microsquare cup with a limiting drawing ratio (LDR) of 1.89 was well formed. Compared to the as-received blank, the annealed blank decreased the drawing force and the earings and increased the LDR. The polyethylene (PE) film, which decreased the drawing force and increased the LDR, was much better than other lubrication conditions. The wrinkles decreased with the increase of the BHF under a specific value. [ABSTRACT FROM AUTHOR]

There have been numerous studies concerning the associations of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D), angiotensin II receptor 1 (AT1R) gene A1166C, and endothelial nitric oxide synthase (eNOS) gene 4b/a polymorphisms with risk of pregnancy hypertensive disorders (PHDs). However, the results are inconsistent. A total of 83 eligible studies (10,354/18,446 cases/controls) were included in this meta-analysis. Pooled odds ratios with corresponding 95% confidence intervals were used to calculate these associations. The effects of ethnicity and types of PHDs were also considered. Results showed significant associations between the ACE gene polymorphism and PHDs in all of the populations except that in Africa. The associations also existed in AT1R, eNOS gene polymorphism and PHDs in part of the gene models in the overall population. These results indicated the ACE gene polymorphism was associated with an increased risk of PHDs, whereas the eNOS and AT1R gene polymorphism only have increased susceptibility to PHDs in part of the gene models. [ABSTRACT FROM AUTHOR]