Search

In this study, the thermal deformation behavior of Cu–Ti–Zr(-Mg) alloys were investigated by Gleeble-1500D. The two alloys were deformed at 700–900 °C with 0.003–10 s−1strain rate. The intrinsic equations of the two alloys were constructed and calculated thermal activation energies, which indicates that it is improved from 325.67 kJ/mol to 344.03 kJ/mol after Mg addition. The result showed that the hot working area of Cu–Ti–Zr alloy is greatly extended after Mg addition, and rheological instability area is reduced. The morphology of the alloys was observed to analyze thermal behavior. It revealed that Mg elements inhibited the occurrence of dynamic recrystallization and shifted the texture types in the alloys by characterization of EBSD. TEM results showed that the phases during hot deformation in Cu–Ti–Zr–Mg are Cu4Ti and Cu10Zr7, which are in a semi-coherent relationship with the Cu matrix.

Action Quality Assessment (AQA) is a task that tries to answer how well an action is carried out. While remarkable progress has been achieved, existing works on AQA assume that all the training data are visible for training at one time, but do not enable continual learning on assessing new technical actions. In this work, we address such a Continual Learning problem in AQA (Continual-AQA), which urges a unified model to learn AQA tasks sequentially without forgetting. Our idea for modeling Continual-AQA is to sequentially learn a task-consistent score-discriminative feature distribution, in which the latent features express a strong correlation with the score labels regardless of the task or action types. From this perspective, we aim to mitigate the forgetting in Continual-AQA from two aspects. Firstly, to fuse the features of new and previous data into a score-discriminative distribution, a novel Feature-Score Correlation-Aware Rehearsal is proposed to store and reuse data from previous tasks with limited memory size. Secondly, an Action General-Specific Graph is developed to learn and decouple the action-general and action-specific knowledge so that the task-consistent score-discriminative features can be better extracted across various tasks. Extensive experiments are conducted to evaluate the contributions of proposed components. The comparisons with the existing continual learning methods additionally verify the effectiveness and versatility of our approach. Data and code are available at https://github.com/iSEE-Laboratory/Continual-AQA.

Single-image super-resolution (SISR) typically focuses on restoring various degraded low-resolution (LR) images to a single high-resolution (HR) image. However, during SISR tasks, it is often challenging for models to simultaneously maintain high quality and rapid sampling while preserving diversity in details and texture features. This challenge can lead to issues such as model collapse, lack of rich details and texture features in the reconstructed HR images, and excessive time consumption for model sampling. To address these problems, this paper proposes a Latent Feature-oriented Diffusion Probability Model (LDDPM). First, we designed a conditional encoder capable of effectively encoding LR images, reducing the solution space for model image reconstruction and thereby improving the quality of the reconstructed images. We then employed a normalized flow and multimodal adversarial training, learning from complex multimodal distributions, to model the denoising distribution. Doing so boosts the generative modeling capabilities within a minimal number of sampling steps. Experimental comparisons of our proposed model with existing SISR methods on mainstream datasets demonstrate that our model reconstructs more realistic HR images and achieves better performance on multiple evaluation metrics, providing a fresh perspective for tackling SISR tasks.

In this study, Al2O3–Cu/35Mo composites were prepared by rapid hot-press sintering-internal oxidation method, and the materials were modified by adding trace amounts of graphene oxide (GO). The results show that the relative densities of the composites are above 99%, the γ-Al2O3generated by internal oxidation is diffusely distributed on the copper matrix. The incorporation of GO produced a small number of hard MoC particles at the interface, which facilitated the interfacial bonding of the composites. In the 30 V DC, 10–30 A electrical contact test, the anode mass of the composites increases, while the cathode mass decreases. And GO reduces the total mass loss of the electric contact by 63.6%, 38.9%, 51.3% and 20.9%, respectively. A comparison of the electrical contact properties of the two materials showed that the addition of GO dispersed the concentrated erosion of the arc. At 10 A and 30 A, the arc energy is reduced by 75.5% and 12.5%, respectively. With the gradual increase in electric current, GO makes the Al2O3–Cu/35Mo composites more stable during the electric contact process, improves the anti-welding ability of the contact and reduces contact resistance.

Compression tests of the Cu-1.5Ti and Cu-1.5Ti-0.5Fe alloys were carried out using the Gleeble-1500D hot deformation simulator. The deformation temperature was 750–900 °C and the strain rate was 0.1–0.003 s−1. The Cu-1.5Ti-0.5Fe alloy clearly shows higher rheological stress and displays dynamic recovery and dynamic recrystallization characteristics under the same deformation conditions. The constitutive equations of the alloys were established. The activation energy of the Cu-1.5Ti alloy was 341.76 kJ/mol, which increased to 378.03 kJ/mol with the addition of 0.5 wt% Fe. After 750 °C and 0.003 s−1deformation the Cu4Ti phase precipitated in Cu-1.5Ti alloy. Adding 0.5 wt% Fe caused dynamic recrystallization during hot deformation. The hot-deformed Cu-1.5Ti-0.5Fe alloy had more dislocations and finer grains with Cu4Ti and Fe2Ti precipitated phases.

The cermet fuels have been considered as a potential key component for the nuclear thermal propulsion, and the homogeneity of the fuel particles in the metal matrix plays a crucial role in stabilizing the structure at extremely high temperatures. In this work, liquid paraffin was used as additive to improve the distribution of yttria-stabilized zirconia (YSZ, an appropriate surrogate for UO2fuel) microspheres in the tungsten (W) matrix, and the W-YSZ cermet wafers (volume ratio 1:1) with a relative density of 97.6% were fabricated by spark plasma sintering with a specifically designed program. The effects of the paraffin dosage (0–5 wt. %) on the homogeneity, microstructure, mechanical properties, and the thermal conductivity of W-YSZ cermet were investigated. The W-YSZ sample with 2 wt. % paraffin shows the highest homogeneity and exhibits the best comprehensive properties, including the ultimate tensile strength of 132.2 MPa at 600 °C, the bending strength of 455 MPa and thermal conductivity of 50 W·m−1·K−1at room temperature. Moreover, the cermet could keep structurally sound after thermal shocked at a heat load of 20 MW·m−2. These results would be helpful for the design and optimization of the cermet fuels in the nuclear thermal propulsion.

A method of collaborative simulation of the train collision process using a rigid motion model and a flexible collision model is proposed to solve the problem of the low computational efficiency of the finite element numerical simulation of the train collision process. This study investigated the collision response of a train derailment hitting a platform with different curve radii based on an accident in which a subway train derailed and hit a platform. Based on the results, a collision damage index is proposed to assess the relative degree of damage of train derailment collisions at different curve radii. The results reveal that within a certain radius of the curve (when the impact distance D exists), there is a positive correlation between the curve radius and the collision damage index, and when the curve radius exceeds a certain value (when the impact distance D doesn’t exist), the train and platform don’t collide.

The hot deformation behavior of Cu–Sn–Ti–(Cr) alloys was studied using Gleeble-1500D thermo-mechanical simulator ranging from 550 to 950 °C, and the strain rate was 0.001–10 s−1. The microstructure evolution of the alloy was analyzed using characterization methods such as electron backscatter diffraction (EBSD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Cu–Sn–Ti–(Cr) alloys were calculated by establishing the constitutive equation of the alloy. The activation energies of Cu–Sn–Ti and Cu–Sn–Ti–Cr alloys are 275.884 and 283.550 kJ/mol, respectively. The results indicate that the addition of Cr element has an inhibitory effect on the nucleation and improve refinement of dynamic recrystallization (DRX) in Cu–Sn–Ti alloy. The texture of Cu–Sn–Ti alloy is Cu texture at 750 °C and the texture contained in Cu–Sn–Ti alloy is Goss texture, Cubic texture and Cu texture when the temperature is raised to 950 °C. The texture of Cu–Sn–Ti–Cr alloy at 750 °C is Goss texture. The Goss texture transforms into Cubic texture and Cu texture when the temperature is raised to 950 °C. The precipitates present in Cu–Sn–Ti alloy include CuSn3Ti5phase and Cu4Ti phase. The addition of Cr element adds a new phase of Cr to the alloy and also makes the distribution of precipitates more uniform and increases in quantity.

High-sensitivity magnetometry is of critical importance to the fields of biomagnetism and geomagnetism. However, magnetometry for dc and low-frequency signal detection faces the challenge of sensitivity improvement, resulting from the low-frequency noise induced by multiple types of noise sources. In particular, for the solid-state spin dc quantum magnetometry, the sensitivity has been limited by short dephasing time. Here, we realized the conversion of the magnetic signal from dc to ac by utilizing a flux concentration and modulation (FCM) technique so that the dynamical decoupling method can be applied to prolong the dephasing time. Hence, we have successfully demonstrated a dc magnetometer with a sensitivity of 32 pT/Hz $^{{1}/{2}}$ , which is about two orders of magnitude over that of the Ramsey-type dc magnetometer. Further enhancement of the sensitivity is systematically analyzed, although is challenging but plenty of room is achievable. Our results shed light on the realization of room temperature dc quantum magnetometry with femtotesla-sensitivity in the future.

• After repetitive thermal loads, the ODS/CDS-W composites experience obvious grain growth and particles shedding, leading to a decrease in mechanical properties. • The interface debonding and progressive shedding of second-phase particles from the W matrix is the main reason for the cracks along the grain boundaries. • The W-ZrC composite exhibits a better thermal shock resistance than W-Y 2 O 3 due to the intrinsic properties of second particles. In a fusion reactor, plasma-facing tungsten (W) materials inevitably suffer severe thermal shock, and the performance of W materials under repetitive high heat loads is one of the key concerns for long-term stable operation of the reactor. In this work, the microstructural evolution and thermal fatigue resistance of two representative W-0.5 wt.% ZrC (WZC) and W-1.0 wt.% Y 2 O 3 (WYO) composites were investigated under cyclic heat loads. Due to the intrinsic properties of ZrC and Y 2 O 3 particles such as coefficients of thermal expansion, particle size and distributions in W grains, the WZC composite exhibited a better thermal shock resistance than WYO. After thermal loads with the absorbed power density (APD) ≥ 22 MW/m2, WYO showed obvious grain growth, Y 2 O 3 particles shedding and degradation of mechanical properties. While, in the case of WZC, these damage behaviors only occurred when APD ≥ 25 MW/m2. Furthermore, an interesting crack mechanism in W composites was revealed due to interface debonding and progressive shedding of second-phase particles from the W matrix. The microstructures and tensile properties of the thermally loaded WZC and WYO specimens were also investigated and the correlations between the microstructure evolution and performance degradation are demonstrated. The results are useful for evaluating the thermal fatigue resistance of oxide/carbide dispersion strengthened W composites and their application in future fusion reactors. [ABSTRACT FROM AUTHOR]

Floater–Hormann rational interpolants and their derivatives converge as O(hjd+1-k)for any set of well-spaced points and any 0≤k≤das the local mesh size hjconverges to zero. In this paper, we extend these results to the Hermite case and investigate the approximation behavior of the k-th derivative of a recently proposed family of barycentric rational Hermite interpolants for any k≥0and any set of well-spaced points. In addition, if the order mof the interpolated derivatives is even, the k-th derivative of the interpolants converges as O(hj(m+1)(d+1)-k);and if the order mof the interpolated derivatives is odd, the k-th derivative of the interpolants converges as O(hj(m+1)(d+1)-1-2k).

Rural residents have unique lifestyle characteristics, energy consumption methods, energy-saving behaviors, and awareness. And the direct carbon emission from rural residents is based on the combined effect of multiple factors. In order to address the complexity of factors affecting the direct carbon emissions from rural household, this study used a structural equation model to examine the effect of multi-factor variables on direct carbon emissions from rural households in central China. Data were collected using questionnaires and surveys in six cities in central China to reflect the daily reality of rural residents. The results show that quality of life and awareness of energy conservation can affect the direct carbon emissions of rural residents. Family characteristics and awareness of energy conservation affected carbon emissions indirectly by affecting the daily behaviors and quality of life of the residents; consumption characteristics, energy-saving behaviors, and energy conservation policies are not the main factors contributing to the direct carbon emissions of the residents. Based on the results, future studies can focus on energy conservation education, improvement of the living habits, coal energy use efficiency, and energy consumption structure of residences.

The visible-light photoredox-catalyzed carboxylation of benzyl chlorides and bromides with CO2has been reported. With inexpensive organic dyes as photocatalysts and amines as electron donors, this carboxylation proceeds well in the absence of sensitive organometallic reagents, transition metal catalysts, or metallic reductants. A wide range of commercially available and inexpensive benzyl halides undergo such carboxylation to give valuable aryl acetic acids, including several pharmaceutical molecules and drug precursors, in moderate to high yields. Moreover, this reaction features mild reaction conditions (one atmospheric pressure of CO2and room temperature), broad substrate scope, good functional group tolerance, easy scalability, and low catalyst loading, thus providing an efficient approach for the assembly of aryl acetic acids.

Extremely low room temperature (RT) ductility and severe discontinuous yielding behavior is a key issue preventing the practical application of Fe–Ga based alloys as structural-functional integration materials in critical fields. Here, we report a combination of Al addition and mechanical treatment that results in RT ductility enhancement of Fe–Ga alloys without discontinuous yielding behavior, while retaining high damping capacities. It was found that the RT ductility of Fe-Ga-Al alloy sheets has a significant increase with increasing Al content and the discontinuous yielding behavior almost disappears, and the enhanced ductility is suggested to originate from the interaction of dislocations and the secondary phase. For Fe82Ga16Al2alloy sheet, the maximal damping value can reach up to ∼0.041, and then damping capacity gradually decreases with increasing Al content but still remains at a high level. The mechanism of damping reduction is suggested to be caused by the limitation of domain wall motion caused by the additional domains generated inside the main domains. This study provides a reference for optimizing the RT ductility of Fe–Ga based alloys while taking into account the functional properties, and is beneficial for promoting the engineering applications of Fe–Ga based alloys as structural-functional integration components.

Moroidin is a bicyclic plant octapeptide with tryptophan side-chain cross-links, originally isolated as a pain-causing agent from the Australian stinging tree Dendrocnide moroides. Moroidin and its analog celogentin C, derived from Celosia argentea, are inhibitors of tubulin polymerization and, thus, lead structures for cancer therapy. However, low isolation yields from source plants and challenging organic synthesis hinder moroidin-based drug development. Here, we present biosynthesis as an alternative route to moroidin-type bicyclic peptides and report that they are ribosomally synthesized and posttranslationally modified peptides (RiPPs) derived from BURP-domain peptide cyclases in plants. By mining 793 plant transcriptomes for moroidin core peptide motifs within BURP-domain precursor peptides, we identified a moroidin cyclase in Japanese kerria, which catalyzes the installation of the tryptophan-indole-centered macrocyclic bonds of the moroidin bicyclic motif in the presence of cupric ions. Based on the kerria moroidin cyclase, we demonstrate the feasibility of producing diverse moroidins including celogentin C in transgenic tobacco plants and report specific cytotoxicity of celogentin C against a lung adenocarcinoma cancer cell line. Our study sets the stage for future biosynthetic development of moroidin-based therapeutics and highlights that mining plant transcriptomes can reveal bioactive cyclic peptides and their underlying cyclases from new source plants.

Since the launch of the Belt and Road Initiative (BRI) in 2013, Myanmar has become a strategic location and important junction connecting the Indian Ocean with inland provinces in southwest China. However, due to the limited container port capacity and poor infrastructure, the country cannot establish efficient intermodal transportation routes between China and Myanmar. Accordingly, this paper attempts to optimise the selection of intermodal transport routes between Chongqing in China and Yangon in Myanmar by sea route and land route, applying fuzzy AHP and TOPSIS methods. The findings in this paper contribute to not only supporting Sino-Myanmar cross-border logistics enterprises to reduce transportation costs and enhancing collaboration between the two countries, but also helping policymakers, who play a key role in empowering and promoting the development of transport routes, proceed required improvements for the efficiency of intermodal transportation chains.

As sessile organisms, plants evolved elaborate metabolic systems that produce a plethora of specialized metabolites as a means to survive challenging terrestrial environments. Decades of research have revealed the genetic and biochemical basis for a multitude of plant specialized metabolic pathways. Nevertheless, knowledge is still limited concerning the selective advantages provided by individual and collective specialized metabolites to the reproductive success of diverse host plants. Here we review the biological functions conferred by various classes of plant specialized metabolites in the context of the interaction of plants with their surrounding environment. To achieve optimal multifunctionality of diverse specialized metabolic processes, plants use various adaptive mechanisms at subcellular, cellular, tissue, organ and interspecies levels. Understanding these mechanisms and the evolutionary trajectories underlying their occurrence in nature will ultimately enable efficient bioengineering of desirable metabolic traits in chassis organisms.

Zirconium carbide (ZrC) nanoparticles with an average size of 5.6 nm were synthesized through laser fragmentation (LF) from as-received 20–60 nm ZrC particles, and LF-ZrC nanoparticle dispersion-strengthened tungsten (LF-WZC) samples were fabricated by spark plasma sintering method. The average grain size of LF-WZC is 1.91 μm and most ZrC particles in LF-WZC are smaller than 10 nm. LF-WZC exhibits finer grain size, higher yield strength and hardness but lower ductility as compared with W-ZrC samples using as-received ZrC (WZC). The results showed that finer ZrC nanoparticles dispersed in tungsten can enhance the strength by hindering the motion of dislocations, but they may also introduce stress concentration and thus reduce the ductility. The thermal shock resistance of the WZC and LF-WZC samples was investigated using an electron beam device. The LF-WZC sample also exhibits a higher cracking threshold (0.33–0.44 GW·m−2) than WZC (0.22–0.33 GW·m−2) at room temperature. The enhanced thermal shock resistance of LF-WZC could be attributed to its high yield strength.

Recent investigations have suggested that microRNA‐129‐5p (miR‐129‐5p) is commonly dysregulated in multiple types of malignancies. Nevertheless, the roles of miR‐129‐5p in human oral squamous cell carcinoma (OSCC) are not well explored. Herein, we demonstrated that miR‐129‐5p was down‐expressed in OSCC cells and tissues. Moreover, miR‐129‐5p overexpression restrained the growth, migration ability, and invasiveness of OSCC cells. Notably, high‐mobility group box 1 protein (HMGB1) was identified as a downstream target of miR‐129‐5p. Additional, knockdown of HMGB1 suppressed the growth and aggressive phenotypes of human OSCC cells. Importantly, re‐expression of HMGB1impaired the inhibitory impacts of miR‐129‐5p on the metastasis of OSCC cells. Altogether, these results implied that miR‐129‐5p restrained the aggressiveness of OSCC cells through modulating HMGB1.

We studied the effects of different cultivars of non‐degermed millet flour fraction and the particle size on Chinese steamed bread to promote the industrial development of the whole‐grain food industry. We used a texture analyzer to analyze the changes introduced by different cultivars of non‐degermed millet flour fraction, and the effect of its particle size on the hardness, adhesiveness, springiness, gumminess, and chewiness parameters, based on the analysis of height‐to‐diameter ratio and specific volume. We obtained samples of different particle size fractions by using 40, 60, 80, 100, 120, and 140 mesh sieves and determined that the particle substitution of non‐degermed millet flour fraction was at a level of 30%. We conducted partial least squares discriminant analysis (PLS‐DA) screening to identify the signature differences of quality components. According to Hunter Laboratory values (whiteness/darkness, L*; redness/greenness, a*; and yellowness/blueness, b*), the results indicated that as the particle size decreased, the L* and whiteness index (W)values decreased but the a* and b* values increased, and the hardness, cohesiveness, adhesiveness, springiness, gumminess, and chewiness parameters of Chinese steamed bread with different particle sizes were significantly different (p< .05). Partial least squares discriminant analysis could distinguish japonica cultivar samples and glutinous cultivar samples. According to the variable influence on projection (VIP) values, we screened chewiness, gumminess, and hardness as the signature differences of the quality components.

Li7La3Zr2O12(LLZO)-based ceramics are well-known as the most promising solid electrolytes for all-solid-state lithium metal batteries. However, its practical application has been significantly hindered by high Li/LLZO interfacial impedance as a result of poor interfacial contact. To solve these issues, in this work, the ZnO layer was magnetron sputter-deposited on Li6.55La2.95Ca0.05Zr1.5Ta0.5O12(LLCZTO) pellets. It was found that by introducing a 200 nm thick ZnO layer, the interfacial area specific resistance was sharply reduced to as low as 1% that of pristine LLCZTO; meanwhile, Li plating/stripping performance was improved significantly with a long life span of 320 h and a low polarization potential of 0.1 V, whereas a thicker ZnO layer of 600 nm can only improve the interface contact to a very limited extent because of the accumulated volume expansion induced by the in situ transformation of ZnO to the Li–Zn alloy, demonstrating the thickness-dependent beneficial effect of the ZnO layer on improving the Li/LLCZTO interfacial contact and therefore reducing the interfacial resistance. Accordingly, the evolution of the interfacial contact mode and the Li+migration mechanism during the Li plating/stripping process without or with ZnO layers of different thicknesses were discussed in detail.

Cobalt-based phosphides show excellent hydrogen evolution reaction (HER) performance, however, improving the intrinsic activity and stability of it in alkaline electrolyte still remains a challenge. Herein, CoRuOH/Co2P/CF with heterojunction structure was developed by means of molten salt and rapid hydrolysis (30 s). The OH−from rapid surface hydrolysis of Co2P as a hydrogen adsorption site can facilitate the formation of thin CoRuOH layer as a water dissociation site, which may bring out better synergistic effect for alkaline HER. Moreover, the covering of CoRuOH can improve the stability of Co2P for HER. When drives at 100 mA/cm2, it only requires overpotential of 81 mV in 1.0 mol/L KOH (25 °C). Even at higher current density (1000 mA/cm2), CoRuOH/Co2P/CF can also operate stability for at least 100 hours. When coupling with NiFe-LDH/IF in a two-electrode system, the voltage of NiFe-LDH/IF(+)|| CoRuOH/Co2P/CF(−)at 1000 mA/cm2is merely 1.77 V with 100 h, demonstrating great potential for water splitting. The implementation of this work provides a new strategy and reference for the further improvement of transition metal phosphides as HER electrocatalysts.

Sesquiterpene scaffolds are the core backbones of many medicinally and industrially important natural products. A plethora of sesquiterpene synthases, widely present in bacteria, fungi, and plants, catalyze the formation of these intricate structures often with multiple stereocenters starting from linear farnesyl diphosphate substrates. Recent advances in next-generation sequencing and metabolomics technologies have greatly facilitated gene discovery for sesquiterpene synthases. However, a major bottleneck limits biochemical characterization of recombinant sesquiterpene synthases: the absolute structural elucidation of the derived sesquiterpene products. Here, we report the identification and biochemical characterization of LphTPS-A, a sesquiterpene synthase from the red macroalga Laurencia pacifica. Using the combination of transcriptomics, sesquiterpene synthase expression in yeast, and microgram-scale nuclear magnetic resonance-coupled crystalline sponge X-ray diffraction analysis, we resolved the absolute stereochemistry of prespatane, the major sesquiterpene product of LphTPS-A, and thereby functionally define LphTPS-A as the first bourbonane-producing sesquiterpene synthase and the first biochemically characterized sesquiterpene synthase from red algae. Our study showcases a workflow integrating multiomics approaches, synthetic biology, and the crystalline sponge method, which is generally applicable for uncovering new terpene chemistry and biochemistry from source-limited living organisms.

Linear IgA bullous dermatosis (LABD) is an acquired autoimmune subepidermal blistering skin disease characterized by circulating and tissue-bound IgA autoantibodies that recognize epitopes within the hemidesmosomal protein BP180, including its NC16A domain. Histologically, LABD has long been defined by neutrophil infiltration and dermal-epidermal separation. However, the pathogenic roles of anti-NC16A IgA and neutrophils in LABD, as well as their interactions, have not been thoroughly studied. We show that passive transfer of patient-derived anti-NC16A IgA induce clinical and histologic LABD pathology in humanized NC16A mice that are reconstituted locally or systemically with human neutrophils. The lesional skin of mice exhibits significantly elevated levels of the neutrophil chemoattractants CXCL-1 and CXCL-2. Furthermore, we show significantly increased levels of the neutrophil chemoattractant IL-8 in blister fluids of patients with LABD. This study provides direct evidence that anti-NC16A IgA in patients with LABD are pathogenic and interact with neutrophils to mediate tissue injury and subepidermal blister formation. This study further corroborates the importance of neutrophil-mediated tissue injury in LABD disease physiology and establishes a clinically relevant in vivo model system that can be used to systematically dissect the immunopathogenesis of LABD.

Cresyl diphenyl phosphate (CDP), an emerging aryl organophosphate ester (OPE), exhibits potential toxic effects and is frequently found in diverse environmental media, thereby raising concerns about environmental pollution. Biodegradation demonstrates substantial potential for CDP removal from the environment. This study investigated the biodegradation mechanisms of CDP using anaerobic activated sludge (AnAS). The biodegradation of 1-mg/L CDP followed a first-order kinetic model with a degradation kinetic constant of 0.943 d−1, and the addition of different electron acceptors affected the degradation rate. High-resolution mass spectrometry identified seven transformation products (TPs) of CDP. The pathways of CDP degradation in anaerobic conditions were proposed, with carboxylation products being the most dominant intermediate products. The structure of the anaerobic microbial community at different degradation time points in CDP-amended microcosms was examined. The linear discriminant analysis (LDA) of effect size (LEfSe) potentially underscored the pivotal role of Methyloversatilisin CDP biodegradation. Zebrafish embryotoxicity experiments revealed both lethal and morphogenetic impacts of CDP on zebrafish embryos. The survival rate, hatching rate, and body length indicators of zebrafish embryos underscored the detoxification of CDP and its resultant intermediates by AnAS. This study offers new insights into the fate and biodegradation mechanisms of CDP in wastewater treatment plants.

The catalytic asymmetric functionalization of readily available 1,3-dienes is highly important, but current examples are mostly limited to the construction of tertiary chiral centers. The asymmetric generation of acyclic products containing all-carbon quaternary stereocenters from substituted 1,3-dienes represents a more challenging, but highly desirable, synthetic process for which there are very few examples. Herein, we report the highly selective copper-catalyzed generation of chiral all-carbon acyclic quaternary stereocenters via functionalization of 1,3-dienes with CO2. A variety of readily available 1,1-disubstituted 1,3-dienes, as well as a 1,3,5-triene, undergo reductive hydroxymethylation with high chemo-, regio-, E/Z-, and enantioselectivities. The reported method features good functional group tolerance, is readily scaled up to at least 5 mmol of starting diene, and generates chiral products that are useful building blocks for further derivatization. Systemic mechanistic investigations using density functional theory calculations were performed and provided the first theoretical investigation for an asymmetric transformation involving CO2. These computational results indicate that the 1,2-hydrocupration of 1,3-diene proceeds with high π-facial selectivity to generate an (S)-allylcopper intermediate, which further induces the chirality of the quaternary carbon center in the final product. The 1,4-addition of an internal allylcopper complex, which differs from previous reports involving terminal allylmetallic intermediates, to CO2kinetically determines the E/Z- and regioselectivity. The rapid reduction of a copper carboxylate intermediate to the corresponding silyl-ether in the presence of Me(MeO)2SiH provides the exergonic impetus and leads to chemoselective hydroxymethylation rather than carboxylation. These results provide new insights for guiding further development of asymmetric C–C bond formations with CO2.

Low temperature sintered MgO-Al2O3-SiO2 glass-ceramic with high mechanical and low thermal expansion was prepared for package. The remarkable influence of B2O3 addition on the electrical, mechanical, and thermal properties was fully investigated. A small amount of B2O3 promoted the sintering process and improved the densification of MAS. The kinetics via Kissinger method indicated that an appropriate B2O3 content decreased the activation energy and helped the occurrence of crystallization. Due to the increase of crystallinity and indialite phase, B2O3 addition significantly enhanced flexural strength and Young’s modulus. MAS doped with 3wt% B2O3 can be sintered at 900 °C and obtained good properties: σ = 229 MPa, φ = 86 GPa, α = 1.66×10-6 /°C, εr = 5.29, and tanδ = 5.9×10-4.

Kava (Piper methysticum) is an ethnomedicinal shrub native to the Polynesian islands with well-established anxiolytic and analgesic properties. Its main psychoactive principles, kavalactones, form a unique class of polyketides that interact with the human central nervous system through mechanisms distinct from those of conventional psychiatric drugs. However, an unknown biosynthetic machinery and difficulty in chemical synthesis hinder the therapeutic use of kavalactones. In addition, kava also produces flavokavains, which are chalconoids with anticancer properties structurally related to kavalactones. Here, we report de novo elucidation of the key enzymes of the kavalactone and flavokavain biosynthetic network. We present the structural basis for the evolutionary development of a pair of paralogous styrylpyrone synthases that establish the kavalactone scaffold and the catalytic mechanism of a regio- and stereo-specific kavalactone reductase that produces a subset of chiral kavalactones. We further demonstrate the feasibility of engineering styrylpyrone production in heterologous hosts, thus opening a way to develop kavalactone-based non-addictive psychiatric therapeutics through synthetic biology. Kava (Piper methysticum), an ethnomedicinal shrub native to the Polynesian islands, produces psychoactive kavalactones and anticancer flavokavains. Structures of key enzymes in their biosynthetic network may enable heterologous production.

Sm2O3 additive significantly influenced the microstructure, mechanical, and electrical properties of BaO-Al2O3-B2O3-SiO2 glass-ceramics. The calculation by the whole pattern fitting method based on XRD patterns revealed that Sm2O3 additive improved the crystallization process of this tetra-system and promoted the formation of major phase quartz. The sintering kinetics showed that Sm2O3 addition markedly reduced the sintering activation energy from 406.86 kJ/mol to 391.38 kJ/mol, which benefited the sintering densification and the grain growth, and thus enhanced mechanical properties. Doping 2% Sm2O3 reinforced the flexure strength from 136.3 to 171.6 MPa and the Young’s modulus from 49.4 to 79.7 GPa. It also exhibited low dielectric constant of 5.31, low dielectric loss of 5.30 × 10-4, and high thermal expansion coefficient of 11.76 × 10-6/°C.

Most P2-type layered oxides suffer from multiple voltage plateaus, due to Na+/vacancy-order superstructures caused by strong interplay between Na–Na electrostatic interactions and charge ordering in the transition metal layers. Here, Mg ions are successfully introduced into Na sites in addition to the conventional transition metal sites in P2-type Na0.7[Mn0.6Ni0.4]O2as new cathode materials for sodium-ion batteries. Mg ions in the Na layer serve as “pillars” to stabilize the layered structure, especially for high-voltage charging, meanwhile Mg ions in the transition metal layer can destroy charge ordering. More importantly, Mg ion occupation in both sodium and transition metal layers will be able to create “Na–O–Mg” and “Mg–O–Mg” configurations in layered structures, resulting in ionic O 2p character, which allocates these O 2p states on top of those interacting with transition metals in the O-valence band, thus promoting reversible oxygen redox. This innovative design contributes smooth voltage profiles and high structural stability. Na0.7Mg0.05[Mn0.6Ni0.2Mg0.15]O2exhibits superior electrochemical performance, especially good capacity retention at high current rate under a high cutoff voltage (4.2 V). A new P2 phase is formed after charge, rather than an O2 phase for the unsubstituted material. Besides, multiple intermediate phases are observed during high-rate charging. Na-ion transport kinetics are mainly affected by elemental-related redox couples and structural reorganization. These findings will open new opportunities for designing and optimizing layer-structured cathodes for sodium-ion batteries.

Sporopollenin is a ubiquitous and extremely chemically inert biopolymer that constitutes the outer wall of all land-plant spores and pollen grains1. Sporopollenin protects the vulnerable plant gametes against a wide range of environmental assaults, and is considered a prerequisite for the migration of early plants onto land2. Despite its importance, the chemical structure of plant sporopollenin has remained elusive1. Using a newly developed thioacidolysis degradative method together with state-of-the-art solid-state NMR techniques, we determined the detailed molecular structure of pine sporopollenin. We show that pine sporopollenin is primarily composed of aliphatic-polyketide-derived polyvinyl alcohol units and 7-O-p-coumaroylated C16 aliphatic units, crosslinked through a distinctive dioxane moiety featuring an acetal. Naringenin was also identified as a minor component of pine sporopollenin. This discovery answers the long-standing question about the chemical make-up of plant sporopollenin, laying the foundation for future investigations of sporopollenin biosynthesis and for the design of new biomimetic polymers with desirable inert properties.

Aromatic l-amino acid decarboxylases (AAADs) are a phylogenetically diverse group of enzymes responsible for the decarboxylation of aromatic amino acid substrates into their corresponding aromatic arylalkylamines. AAADs have been extensively studied in mammals and plants as they catalyze the first step in the production of neurotransmitters and bioactive phytochemicals, respectively. Unlike mammals and plants, the hallucinogenic psilocybin mushroom Psilocybe cubensisreportedly employs an unrelated phosphatidylserine-decarboxylase-like enzyme to catalyze l-tryptophan decarboxylation, the first step in psilocybin biosynthesis. To explore the origin of this chemistry in psilocybin mushroom, we generated the first de novotranscriptomes of P. cubensisand investigated several putative l-tryptophan-decarboxylase-like enzymes. We report the biochemical characterization of a noncanonical AAAD from P. cubensis(PcncAAAD) that exhibits substrate permissiveness toward l-phenylalanine, l-tyrosine, and l-tryptophan, as well as chloro-tryptophan derivatives. The crystal structure of PcncAAAD revealed the presence of a unique C-terminal appendage domain featuring a novel double-β-barrel fold. This domain is required for PcncAAAD activity and regulates catalytic rate and thermal stability through calcium binding. PcncAAAD likely plays a role in psilocybin production in P. cubensisand offers a new tool for metabolic engineering of aromatic-amino-acid-derived natural products.

Bialaphos resistance (BAR) and phosphinothricin acetyltransferase (PAT) genes, which convey resistance to the broad-spectrum herbicide phosphinothricin (also known as glufosinate) via N-acetylation, have been globally used in basic plant research and genetically engineered crops1–4 . Although early in vitro enzyme assays showed that recombinant BAR and PAT exhibit substrate preference toward phosphinothricin over the 20 proteinogenic amino acids1 , indirect effects of BAR-containing transgenes in planta, including modified amino acid levels, have been seen but without the identification of their direct causes5,6 . Combining metabolomics, plant genetics and biochemical approaches, we show that transgenic BAR indeed converts two plant endogenous amino acids, aminoadipate and tryptophan, to their respective N-acetylated products in several plant species. We report the crystal structures of BAR, and further delineate structural basis for its substrate selectivity and catalytic mechanism. Through structure-guided protein engineering, we generated several BAR variants that display significantly reduced non-specific activities compared with its wild-type counterpart in vivo. The transgenic expression of enzymes can result in unintended off-target metabolism arising from enzyme promiscuity. Understanding such phenomena at the mechanistic level can facilitate the design of maximally insulated systems featuring heterologously expressed enzymes. The herbicide-resistant BARgene is broadly used in different plants. The current study reports the first crystal structure of the BAR enzyme and further demonstrate structure-guided engineering strategies to reduce the non-specific activities of BAR.

A novel oCNT-Chitosan-xFe2O3⋅yBi2O3nanocomposite has been synthesized as a catalyst for the reduction of nitroarenes to afford corresponding anilines. This catalyst exhibits excellent efficiency and high chemoselectivity towards varieties of nitro-compounds by using hydrazine hydrate as the reductant, and this magnetically separable nanocatalyst can be used for more than ten cycles. The synergy between iron and bismuth gives the catalyst competitive activity towards precious metallic catalyst, and the active sites are immobilized on the chitosan noncovalently functionalized oxidized carbon nanotubes gives the catalyst long life time. Furthermore, this heterogeneous catalyst was used in a continuous-flow processing by filling up it into a packed bed reactor. It was used for more than 1000 min without any loss of catalytic activity in a scaled-up reduction of p-nitrophenol with a productivity of 0.5mmol min−1.

The 0.5Y2O3/Al2O3-Cu/30Mo3SiC and 0.3GO-0.5Y2O3/Al2O3-Cu/30Mo3SiC composites were fabricated by fast hot press sintering. Hot compression tests of the composites were carried out using the Gleeble-1500 simulator at 0.001–10 s−1strain rates and 650–950 °C deformation temperatures. The effects of doped reduced graphene oxide (rGO) on the hot deformation behavior and microstructure of 0.5Y2O3/Al2O3-Cu/30Mo3SiC composites were investigated. Trace of molybdenum carbide (MoC) layers/nanoparticles formed in-situ at the rGO-Cu/Mo interface, which is beneficial to the interfacial bonding of the composite. The enhanced flow stress and activation energy of hot deformation is attributed to the addition of the rGO. The activation energy of the composites was improved by 11% with the addition of rGO. The dislocation density and texture orientation ratio decrease at higher deformation temperatures.

Hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT) is an essential acyltransferase that mediates flux through plant phenylpropanoid metabolism by catalyzing a reaction between p-coumaroyl-CoA and shikimate, yet it also exhibits broad substrate permissiveness in vitro. How do enzymes like HCT avoid functional derailment by cellular metabolites that qualify as non-native substrates? Here, we combine X-ray crystallography and molecular dynamics to reveal distinct dynamic modes of HCT under native and non-native catalysis. We find that essential electrostatic and hydrogen-bonding interactions between the ligand and active site residues, permitted by active site plasticity, are elicited more effectively by shikimate than by other non-native substrates. This work provides a structural basis for how dynamic conformational states of HCT favor native over non-native catalysis by reducing the number of futile encounters between the enzyme and shikimate.

Firefly luciferin is a specialized metabolite restricted to fireflies (family Lampyridae) and other select families of beetles (order Coleoptera). Firefly luciferin undergoes luciferase-catalyzed oxidation to produce light, thereby enabling the luminous mating signals essential for reproductive success in most bioluminescent beetles. Although firefly luciferin and luciferase have become widely used biotechnological tools, questions remain regarding the physiology and biochemistry of firefly bioluminescence. Here we report sulfoluciferin to be an in vivo derivative of firefly luciferin in fireflies and report the cloning of luciferin sulfotransferase (LST) from the North American firefly Photinus pyralis. LST catalyzes the production of sulfoluciferin from firefly luciferin and the sulfo-donor PAPS. Sulfoluciferin is abundant in several surveyed firefly genera as well as in the bioluminescent elaterid beetle Pyrophorus luminosusat a low level. We propose that sulfoluciferin could serve as a luciferin storage molecule in fireflies and that LST may find use as a new tool to modulate existing biotechnological applications of the firefly bioluminescent system.

The bearing lubrication system flow distribution design of the transmission was realized with a new system modeling method, targeted at the problem of a certain type of transmission’s bearings’ sintering. The heat-generated model and the flow-required model of the bearings and the gears were set up, and the required lubrication flow was obtained. The simulation model of the system flow distribution was established, the simulation analysis toward the dynamic characteristic of the transmission’s lubrication flow’s distribution was performed, and the results of the simulation analysis and the test were analyzed comparatively. The result showed that the simulation model matched the test result well, proving the effectiveness and correctness of the model of the transmission’s flow distribution.

Based on single-pass InSAR system, the inteferometric phase and InSAR 3 D imaging characteristics of target with rotational micro-motion are studied, and the "barrier" effect of target with rotational micro-motion in the InSAR image is revealed for the first time. Firstly, both 3D geometric model and signal model of the rotational target with arbitrary attitude are built in this paper, and the imaging results are derived. Then, by comparing the imaging results of InSAR's two channels, the interferometry phases of the rotational target are proved to be approximate equal to the inteferometry phase of the location where the rotational center lies in, and the effect of the rotational parameters and the attitude of the rotational target can be neglected. On the basis, it is pointed out that the InSAR image result of the rotational target shows the "barrier" effect which spreads along the cross range direction. The height and the length of the "barrier" depend on the vertical direction coordinate of the rotation center and the rotational parameters respectively. The analyses are verified by simulation experiments. [ABSTRACT FROM AUTHOR]

The structure and principle of the nozzle electro-hydraulic servo valve was introduced, and the complicated characteristics of mechanical, electrical, hydraulic, and magnetic are studied in this paper. The model of the nozzle electro-hydraulic servo valve was built based on the ITI-SimulationX software platform. The static and dynamic simulation processes were presented and analyzed regarding the nozzle electro-hydraulic servo valve. The nozzle electro-hydraulic servo valve has some advantages of rapid time respond, high stability and reliability. This paper shows the special capabilities of SimlationX to develop such a multi-domain model.

Vitamin A is an essential nutrient element in animal and human growth, which is usually produced by partially acetylating and transforming retinyl diol. The lipase-catalyzed mono-acetylation can obtain pure monoacetate compared with the classical chemistry process. In the current work, the synthesis of vitamin A precursor of Candida antarctica lipase B catalyzed by regioselective monoacetylation of primary hydroxyl of diol in n-hexane was studied. The reaction rate could be described in terms of the Michaelis-Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both substrates. A kinetic model was developed, and the apparent kinetic parameters were calculated as: Vmax =8.45 mmol/ (L•h); K m, vinyl =0.997 mmol/L; K m, diol =161.28 mmol/L; K i, diol =287.32 mmol/L; K i, monoacetate=18.13 mmol/L; and K I, diol =427.40 mmol/L. The current study indicates a competitive enzyme inhibition of highly concentrated diol during lipase-catalyzed acetylation reaction. When the diol concentration in the medium was low, there was a good conformity between the experimental and simulated values with 4.73% average relative error.

The asymmetric reduction of ethyl 4-chloro-acetoacetate (CAAE) to ethyl (R)-4-chloro-3- hydroxybutanoate (R-CHBE) biocatalysed by the aldehyde reductase of Sporobolomyces salmonicolor expressed in E. coli M15 (pQE30-alr) in combination with regeneration of NADPH by the glucose dehydrogenase of Bacillus megaterium expressed in E. coli M15 (pQE30-gdh) was reported. The bioreduction was carried out in a two-phase reaction system with n-butyl acetate as an organic solvent. Bioconversion of 300 mmol CAAE with a final yield of 97.5 % and an enantiometric excess of 99 % was achieved without the addition of cofactor NADPH.

This article through to the typical geological disaster investigation of the 307 national road sections, analyzes the main causes of the disaster, the typical section the slope body risk analysis and stability evaluation, and put forward the reasonable management plan and the suggestion.

This article describes the Xingtai City, a typical large-scale modern coal mine, mine environmental geological problems arising due to the exploitation of coal resources, and the corresponding countermeasures and suggestions for different problems. Mainly introductions are the destruction of water resources, mine water hazard, mining subsidence and destruction of land resources, and guiding role in the safe production of coal and the surrounding environmental governance.

Feature extraction is an important phase in SAR imagery interpretation and target recognition, electromagnetic scattering characteristic is the inherent characteristic of target on SAR imagery. High resolution SAR imagery interpretation and target recognition, particularly the ground vehicles recognition, needs to be carried through based on target scattering characteristic and target’s electromagnetic feature extraction. This paper analyzes the electromagnetic scattering mechanism of typical ground vehicles firstly, and the feasibility of modeling the electromagnetic scattering characteristic of ground vehicles with attributed scattering center model has been discussed in brief. And then, by making some improvement on the existing method of attributed scattering center feature extraction from SAR imagery, a modified method for feature extraction of ground vehicles from measured high resolution SAR imagery based on electromagnetic scattering characteristic has been proposed. Finally, performance of the proposed algorithm has been validated on measured 0.3m resolution MSTAR and 0.1m resolution MiniSAR SAR imagery data.

Based on the S202 a typical section of the geological hazard investigation and the study of fuzzy comprehensive judgement method, this paper make the comprehensive evaluation of geological hazard, and then it makes a partition evaluation ,provides the basis for the section roads of the geological disaster prevention.

With the conventional oil and gas development and consumption, unconventional oil and gas becomes more and more important. Unconventional oil and gas development in China should consider some opportunities and challenges. These include developed technique and success methods in other countries, the variable price of oil and gas, the quality and quantity of reserves distribution, taxes policies and the increasing quantity of oil and gas consumption and demand.

The carrier frame is the installation base of ROV’s each subsystem and the main force component when lifted and recycled. Its research is designed to ensure sufficient strength, stiffness and weight as small as possible.In order to seek the optimal design proposal in initial stage of design, the finite element analysis and size optimization of one under researching ROV’s carrier frame are carried out.According to the result of optimization, the structural mechanics performance after optimization could basically remain unchanged, also the weight of the structural reduces 5.8 percent.