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The age of the Silurian “Lower Red Beds” (LRBs), which occur widely in South China, has long been controversial because of the scarcity of index fossils. Here, we report a fauna with abundant trilobites from the LRBs in Wuhan, Middle Yangtze region, consisting of Aulacopleura (Paraaulacopleura) pijiazhaiensis, ‘Encrinuroides’ yichangensis, Gaotania hubeiensis, Hyrokybe gaotanensis, Japonoscutellum yichangense, Latiproetus latilimbatus, and Ptilillaenus lojopingensis. These trilobites are common in the Leijiatun, upper Xiangshuyuan, Shihniulan, and Lojoping formations in the Upper Yangtze region, and belong to the middle to upper Aeronian Ptilillaenus or ‘Encrinuroides’–Ptilillaenus–Latiproetus assemblages. The discovery of this trilobite assemblage suggests that the LRBs are probably partly of middle–late Aeronian age in the Middle Yangtze region. Thus, the lower boundary of the LRBs is likely diachronous in the Yangtze region, ranging from the middle–late Aeronian to the early Telychian. The discovery of the Ptilillaenus assemblage in the Wuhan LRBs expands the paleogeographic distribution of this assemblage and provides evidence of deeper depositional environment of the LRBs in the study area versus shallow waters in other areas of the Yangtze region.

Horse-rider interaction analysis by wearable sensors is a promising tool for monitoring equestrian training. In this paper, a body sensor network (BSN) based equestrian motion analysis system is developed, which combines bespoke inertial measurement units and MindWave electroencephalography (EEG) acquisition equipment. To fuse the mechanical and EEG signals collected from the system, emotional and attitude information can be obtained to analyze the interaction between the rider and horse in equestrian training. For motion data fusion, a novel method, exercise intensity extend kalman filter (EID-EKF), is proposed, which can also reconstruct the riders' posture in by establishing a biomechanical model. The accuracy of our method is verified with the optical system Vicon to support the motion capture for four riding styles. Finally, the emotion changes of the riders with different levels are quantified, and kinematic analysis is carried out by combining with inertial and emotional information. It is concluded from the experiment results that the estimation errors are well controlled, and motion patterns acquired according to the kinematic analysis are consistent with the actual situation.

C30H25N11O8Cd, orthorhombic, Pnma (no. 62), a = 17.9344(3) Å, b = 18.2722(3) Å, c = 9.5619(2) Å, V = 3133.44(10) Å3, Z = 4, R gt (F) = 0.0345, wR ref (F 2) = 0.0707, T = 293.28(10) K.

Using a flexible bis (triazole) ligand BBPTZ, where BBPTZ = 4,4'- bis (1,2,4-triazol-1-ylmethyl) biphenyl, a novel compound of [Ni2(BBPTZ)4][β-Mo8O26] (1) based on [NiN4O2]2+ secondary building unit (SBU) and [β-Mo8O26]4– cluster was synthesized by hydrothermal method. In compound 1, the [NiN4O2]2+ SBUs serving as 2-connected joints were directly connected [β-Mo8O26]4– clusters forming 1D inorganic strips. The adjacent strips were assembled through two types of BBPTZ ligands along the c axis, giving rise to 2D layers. It exhibits not only good thermal stability but also bifunctional electrocatalytic activity. When using it as the electrocatalyst for the electrochemical sensing for bromate, it shows a broad sensor range (1.35–4.75 mM) and comparable sensitivity of 62.39 µA cm−2 mM−1. Moreover, it also exhibits a remarkable activity towards the hydrogen evolution reaction, with a 248 mV onset potential, a Tafel slope of 131 mV dec−1, and a η10 of 386 mV.

Determine the main factors affecting carbon emissions of the Chinese steel industry is indispensable commitments to achieve the sustainable development of China. Hereby, based on the Stochastic Impacts by Regression on Population, Affluence and Technology (STIPRAT) model, this paper combines the economic growth function, carbon emission production function, and the FDI function of the Chinese steel industry, and uses the three-stage least square equation model (3SLS) to analyze the relationship between China’s economic growth, carbon emissions in the steel industry, and FDI (foreign direct investment) inflows. The results document a complete two-way causal relationship of three variables in the whole country and the Western region, while the relationship in the Eastern region and the Central region is not complete. Moreover, there are no bidirectional causal relationship between carbon emissions and FDI in the Eastern region, while only bidirectional causality between carbon emissions and FDI in the Central region. These findings are of great significance for the Chinese steel industry to formulate effective emission reduction policies.

The discovery of dynamic and reversible modifications in RNA expands their functional repertoires. Now, RNA modifications have been viewed as new regulators involved in a variety of biological processes. Among these modifications, thiolation is one kind of special modification in RNA. Several thiouridines have been identified to be present in RNA, and they are essential in the natural growth and metabolism of cells. However, detection of these thiouridines generally is challenging, and few studies could offer the quantitative levels of uridine modifications in RNA, which limits the in-depth elucidation of their functions. Herein, we developed a chemical derivatization in combination with mass spectrometry analysis for the sensitive and simultaneous determination of uridine thiolation and hydroxylation modifications in eukaryotic RNA. The chemical derivatization strategy enables the addition of easily ionizable groups to the uridine thiolation and hydroxylation modifications, leading up to a 339-fold increase in detection sensitivities of these modifications by mass spectrometry analysis. The limits of detection of these uridine modifications can be down to 17 amol. With the established method, we discovered and confirmed that a new modification of 5-hydroxyuridine (ho5U) was widely present in small RNAs of mammalian cells, expanding the diversity of RNA modifications. The developed method shows superior capability in determining low-abundance RNA modifications and may promote identifying new modifications in RNA, which should be valuable in uncovering the unknown functions of RNA modifications.

A direct decarbonylative Sonogashira coupling of terminal alkynes with carboxylic acids was achieved through palladium catalysis. This reaction did not use overstoichiometric oxidants, thus overcoming the homocoupling issue of terminal alkynes. Under the reaction conditions, a wide range of carboxylic acids including those bioactive ones could couple readily with various terminal alkynes, thus providing a relative general method for preparing internal alkynes.

The flow-induced crystallization of poly(vinylidene fluoride) (PVDF)–ion composites in the presence of externally added ions was investigated by in situ wide-angle X-ray diffraction (WAXD) and ex situ Fourier transform infrared (FTIR) spectroscopy. In this work, two types of hexadecyl trimethyl ammonium bromide (CTAB) and tetrabutylammonium hydrogen sulfate (TBAHS) ions with distinct electrostatic interactions were chosen at a weight concentration of 0.5% to design different influences on crystallization. For quiescent crystallization, TBAHS ions induced the appearance of the polar γ-phase with accelerated kinetics, but CTAB ions exhibited no detectable influence in the crystallization of the nonpolar α-phase as in neat PVDF. Interestingly, flow induced the formation of β-phase with prominent piezo/ferroelectricity and the presence of ions could increase the amount of this flow-generated β-phase. With a strain of 2.7 applied at 1 s–¹, the CTAB and TBAHS ions increased the crystallinity index of the β-phase obtained just after the flow to 2.4 and 3.6%, respectively, with respect to that of 2.0% in neat PVDF. In addition, the ions could increase the enhancement amplitude of the flow-generated β-phase by increasing the strain rate over a broad range from 0.01 to 10 s–¹. Moreover, both CTAB and TBAHS ions induced the crystallization of the γ-phase during the isothermal process at a high temperature of 160 °C, where the α-phase appearing in neat PVDF was completely suppressed.

Ammonia is a good hydrogen carrier and can be well combined with hydrogen for combustion. The combustion performance of the mixtures of ammonia and hydrogen in a medium-speed marine diesel engine was investigated theoretically. The HCCI combustion mode was selected for reducing thermal-NOx production. The start fire characteristic of the NH3–H2 mixtures was studied under different equivalence ratio, hydrogen-doped ratio, and intake air temperature and pressure. Then, the combustion performance of the NH3–H2 mixtures (doping 30% hydrogen) was analyzed at a typical operation condition of engine. The addition hydrogen improved the laminar flame velocity of ammonia, and affected the NOx emission. For the medium-speed marine engine fueled with NH3–H2, reducing combustion temperature, introducing EGR and combining with post-treatment technology would be a feasible scheme to reduce NOx emission.

Two pairs of cycloneolignane enantiomers, piperhancins A and B (1 and 2, respectively), along with two enantiomeric pairs of biosynthetic related neolignanes, hancinone C (3) and piperhancin C (4), were isolated from the stems of Piper hancei. Compound 1 is an unprecedented 1',2:1,2'-dicyclo-8,3'-neolignane. Their structures and absolute configurations were elucidated by spectroscopic analyses, X-ray diffraction, and electronic circular dichroism calculations. Among all of the isolates, compounds (+)-1, (-)-1, (+)-2, (-)-2, and (+)-3 could significantly inhibit the production of nitric oxide secreted by lipopolysaccharide (LPS)-induced neuroinflammation in BV-2 microglial cells, with IC50 values of 1.1-26.3 μM. In addition, compound (-)-1 could decrease the mRNA levels of iNOS, IL-6, and TNF-α induced by LPS in BV-2 microglial cells.

Cu-based MOFs, i.e., HKUST-1, etc., have been pertinently chosen as the pristine materials for CO2ER due to the unique ability of copper for generation hydrocarbon fuel. However, the limited conductivity and stability become the stumbling-block that prevents the development of it. The exploring of MOFs-derived M−C materials starts a new chapter for the MOFs precursors, which provides a remarkable electronic connection between carbon matrix and metals/metal oxides. N-doped M−N−C with extensive M−N sites scattering into the carbon matrix are more popular because of their impressive contribution to catalytic activity and specific product selectivity. Nevertheless, Cu–N–C system remained undeveloped up to now. The lack of ideal precursor, the sensitivity of Cu to be oxidized, and the difficulties in the synthesis of small size Cu nanoparticles are thus known as the main barriers to the development of Cu–N–C electrocatalysts. Herein, a nitrogen-rich Cu–BTT MOF is employed for the derivation of N-doped Cu–N–CT composite electrocatalysts by the pyrolyze method. High-temperature pyrolysis product of Cu–N–C1100 exhibits the best catalytic activity for productions of CO (−0.6 V vs. RHE, jCO = 0.4 mA/cm2) and HCOOH (−0.9 V vs. RHE, jHCOOH = 1.4 mA/cm2).

The Permian–Triassic Mass Extinction (PTME) resulted in the most severe loss of life in the history of the earth, both marine and terrestrial ecosystems suffered heavy losses simultaneously, and the biotic recovery process was difficult for both. There are many studies on the timing and pattern of this mass extinction, however, the consistency of the recovery between the marine and terrestrial facies remains controversial. In particular, few metazoans survived and the deposits were dominated by the microbialites during the Early Triassic. The reappearance of the metazoans signified the beginning of the biotic recovery. In this paper, we measured the trace fossils of the Heshanggou Formation in western Henan, North China, which plays an important role in the transformation from the flourishing of the microorganisms to the recovery of metazoans. We quantitatively described the characteristics and measured the diameter, depth, abundance and diversity of the trace fossils. Based on the acquired data, the lower part of the Heshanggou Formation is confined to simple, small, vertical burrows, suggesting that the ecological environment was suitable for the survival of special species. In the middle part, the vertical burrows become deeper, which may be due to the adaptation of organisms to the harsh environment. Disturbance is more intense and the diversity clearly increases in the upper part. Through the increasing bioturbation and diversity of the trace fossils, we found a gradual biotic recovery pattern in the Early Triassic, and the recovery mode is similar to marine ichnofossils in South China.

A facile and general method for constructing carbon-heteroatom (C-P, C-O, C-S, and C-N) bonds via C-N cleavage of benzyl ammonium salts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammonium salts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated. The scale-up reaction and one-pot synthesis were also successfully performed.

L-5-methyltetrahydrofolate (5-MTHF) is one of the biological active forms of folate, which is widely used as a nutraceutical. However, low yield and serious pollution associated with the chemical synthesis of 5-MTHF hampers its sustainable supply. In this study, 5-MTHF production was improved by engineering the 5-MTHF biosynthesis pathway and NADPH supply in Lactococcus lactis for developing a green and sustainable biosynthesis approach. Specifically, overexpressing the key rate-limiting enzyme methylenetetrahydrofolate reductase led to intracellular 5-MTHF accumulation, reaching 18 μg/l. Next, 5-MTHF synthesis was further enhanced by combinatorial overexpression of 5-MTHF synthesis pathway enzymes with methylenetetrahydrofolate reductase, resulting in 1.7-fold enhancement. The folate supply pathway was strengthened by expressing folE encoding GTP cyclohydrolase I, which increased 5-MTHF production 2.4-fold to 72 μg/l. Furthermore, glucose-6-phosphate dehydrogenase was overexpressed to improve the redox cofactor NADPH supply for 5-MTHF biosynthesis, which led to a 60% increase in intracellular NADPH and a 35% increase in 5-MTHF production (97 μg/l). To reduce formation of the by-product 5-formyltetrahydrofolate, overexpression of 5-formyltetrahydrofolate cyclo-ligase converted 5-formyltetrahydrofolate to 5,10-methyltetrahydrofolate, which enhanced the 5-MTHF titer to 132 μg/l. Finally, combinatorial addition of folate precursors to the fermentation medium boosted 5-MTHF production, reaching 300 μg/l. To the best of our knowledge, this titer is the highest achieved by L. lactis. This study lays the foundation for further engineering of L. lactis for efficient 5-MTHF biosynthesis.

The increase of affected river reaches by reservoirs has drastically disturbed the original hydrological conditions, and subsequently influenced the nutrient biogeochemistry in the aquatic system, particularly in the cascade reservoir system. To understand the seasonal variation of nitrogen (N) behaviors in cascade reservoirs, hydrochemistry and nitrate dual isotopes (δ15N-NO3- and δ18O-NO3-) were conducted in a karst watershed (Wujiang River) in southwest China. The results showed that NO3--N accounted for almost 90% of the total dissolved nitrogen (TDN) concentration with high average concentration 3.8 ± 0.4 mg/L among four cascade reservoirs. Higher N concentration (4.0 ± 0.8 mg/L) and larger longitudinal variation were observed in summer than in other seasons. The relationship between the variation of NO3--N and dual isotopes in the profiles demonstrated that nitrification was dominated transformation, while assimilation contributed significantly in the epilimnion during spring and summer. The high dissolved oxygen concentration in the present cascade reservoirs system prevented the occurrence of N depletion processes in most of the reservoirs. Denitrification occurred in the oldest reservoir during winter with a rate ranging from 18 to 28%. The long-term record of surface water TDN concentration in reservoirs demonstrated an increase from 2.0 to 3.6 mg/L during the past two decades (~ 0.1 mg/L per year). The seasonal nitrate isotopic signature and continuously increased fertilizer application demonstrated that chemical fertilizer contribution significantly influenced NO3--N concentration in the karst cascade reservoirs. The research highlighted that the notable N increase in karst cascade reservoirs could influence the aquatic health in the region and further investigations were required.

Mg alloys have been regarded as revolutionary metallic biomaterials for biodegradable bone implants, but their applications are mainly blocked by the too rapid degradation in physiological environment. This study explores the dual alloying effects of Mn and/or Sn on the performance of Mg alloys prepared by selective laser melting. The observed microstructure indicated remarkable refinement of both the grains and intermetallic phases in the Mn- and/or Sn-containing alloys during the rapid solidification process. Moreover, approximately a half decrease in corrosion rate was observed for AZ61–0.4Mn-0.8Sn alloy with respect to AZ61 alloy. The improved corrosion behavior was primarily due to the enhanced protective effects of surface layers, in which Mn- and/or Sn-rich phases acted as a helpful barrier against medium penetration and thereby alleviated the current exchange with the matrix. In addition, the solute Mn and/or Sn positively shifted the corrosion potential, which also brought about a better corrosion resistance. Furthermore, the strength and hardness of the alloys were also effectively improved and comparable to those of cortical bone. This could be ascribed to the dissolved Mn and/or Sn atoms and the finely dispersed intermetallic phases, which might cause lattice distortion and precipitation hardening. Besides, the Mn- and/or Sn-containing alloys showed good cytocompatibility as indicated by the normal morphology and increased viability of MG-63 cells. These findings suggest that the developed AZ61-Mn-Sn alloy is a promising candidate for biodegradable bone implants.

The direct C–H arylation and acylation of azoles with carboxylic acids were achieved through Pd/Cu cooperative catalysis. Various biaryls and biaryl ketones were selectively produced in good to high yields from the same substrates. The key factor of high chemoselectivity was the choice of a suitable phosphine ligand: biaryls were generated selectively with dppp as the ligand, while biaryl ketones were obtained with high selectivity using dpph or Ph2PCy as the ligand.

Carboxymethyl cellulose-foam-supported HKUST-1@graphdiyne (HK@GDY/CMC-B) was constructed with high thermal conductivity and directional channels to enhance the ad-/de-sorption efficiency of acetaldehyde. Characterization results showed that (1) HKUST-1 grew within CMC and GDY via an in situ tri-phase cross-linking strategy, forming a special “alkynyl|Cu|COOH” interface, which maintained the high BET surface area (945.1 m2 g−1) of the HK@GDY/CMC-B foam and established a tight connection among the different components of the composite; (2) the π-conjugated carbon structure of GDY and the unique “alkynyl|Cu|COOH” interface within HK@GDY/CMC-B accelerated the phonon conduction and significantly enhanced the thermal conductivity of HK@GDY/CMC-B (336 mW m−1 K−1); (3) the directional channels and the hierarchical pore structure with a unique interface in the HK@GDY/CMC-B foam facilitated the diffusion and adsorption of VOCs; (4) the compact “alkynyl|Cu|COOH” interface generated more unsaturated Cu(II) and Cu(I) sites and increased adsorbent surface polarity to capture acetaldehyde. Consequently, the obtained HK@GDY/CMC-B exhibited an excellent acetaldehyde adsorption capacity of up to 11.0 mmol g−1, which was 1.3–3.4 times higher than that of many state-of-the-art adsorbents. Kinetics performance data revealed that the diffusivity of acetaldehyde on the HK@GDY/CMC-B foam increased by 60% compared to that of the pristine HKUST-1. Similarly, the desorption rate of HK@GDY/CMC-B was 2.2–6.5 times faster than that of several state-of-the-art adsorbents under similar temperature programmed desorption. This greatly realized an energy-conserving approach for adsorbent regeneration. Based on these findings, the current tri-phase cross-linking strategy can be deemed as an efficient tactic to further improve the adsorption efficiency of MOFs for fast adsorption of VOCs on the commercial level.

An Fe3O4/carboxymethyl cellulose (Fe3O4/CMC) magnetic biosorbent was prepared using the ion-imprinting technology, where La(III) was used as the template ion. The morphology and structure of Fe3O4/CMC were characterized by SEM, FTIR and XRD. It is found that nano Fe3O4 with inverse spinel structure can distribute in CMC and endow the composite with good magnetic properties. The adsorption performance such as adsorption capacity, influence of pH and initial concentration were fully explored. The prepared Fe3O4/CMC is revealed to have good adsorption properties with Qmax of 61.5 mg g−1, in line with the pseudo-second-order kinetic model. When handling the multi-ion coexistence solution of Cu(II), Ni(II) and Cd(II), Fe3O4/CMC shows high selective adsorption for La(III). Meanwhile, cycling experiments find that the adsorption capacity is only slightly reduced (less than 5%) after 5-time reuse. Good adsorption properties, high selectivity and easy recovery give the newly-synthesized Fe3O4/CMC biosorbent broad application potential in the treatment of La(III)-containing wastewater.

Halides are one type of important IR nonlinear-optical material candidate. Here, a mixed alkali metal and d0 transition-metal fluoride, namely, KNa2ZrF7, was obtained by a facile hydrothermal method. It crystallizes in an orthorhombic system with the polar space group Pmn21, and its pseudo-1D structure features isolated (ZrF7)3- moncocapped trigonal prisms, which are ionically linked together by countercations K+ and Na+, representing a new type of fluoride. The powder sample of KNa2ZrF7 exhibits a moderate second-harmonic-generation response and a high laser-induced damage threshold. Besides, it can realize phase matchability and possesses a wide-IR transparent window. Thermal stability analysis suggests that KNa2ZrF7 is a congruent compound. Structural comparisons with related fluorides and theoretical calculations are also presented in this work.

Interaction of [Pb(SiPr)2]n with 1.5 equiv. of AgNO3 in DMF under aerobic conditions at room temperature gave a cationic lead-centered thiolate cluster [Pb13(SiPr)6O8](NO3)4 (1). While treatment of [Pb(SiPr)2]n in refluxing DMF in air afforded a two-dimensional layered structure of [Pb14(SiPr)16O6]n (2), comprising of [Pb14(SiPr)18O6]2− units bridged the iPrS− moieties. Molecular structures of the two oxidation products of μ4-oxygen-bridged high-nuclearity lead(II) clusters have been determined by single-crystal X-ray analysis. The UV/Vis properties of the two clusters in both solid state and solution state were also investigated in this paper.

Co-Cr-Mo alloy is an excellent wear-resistant material which is widely used in many industrial fields. Due to external vibrations, fretting wear often occurs at the interfaces of well-matched connectors and induces surface wear, resulting in an accumulation of wear debris on the contact surfaces. This leads to a damage at the interface and the deterioration of matching contact pairs. Excellent wear and corrosion resistance are essential requirements for ideal industrial materials to resist the increasingly harsh working conditions of Co-Cr-Mo alloy, such as elevated temperatures. In this study, the fretting wear resistance of a Co-Cr-Mo alloy was investigated for different test parameters (temperatures, normal loads and displacements) with friction equipment. The fretting wear degree of the alloy was slight at 25 °C, and the wear mechanism at 25 °C was mainly abrasive wear. The analyses showed that elevated temperatures accelerated oxidative adhesion wear due to the formation of an oxide layer inside the interfaces and led to severe adhesive wear.

A functionalized resorcinarene (1) containing four thiol groups on the upper rim and four long nonyl groups on the lower rim was synthesized. Compound 1 was used as organic template and pre-reducing agent for the preparation of small gold nanoparticles with different sizes. The morphology and size of the gold nanoparticles could be changed by altering the concentration of tetraarylthiol resorcinarene 1 or the amount of reducing agent sodium borohydride. Tetraarylthiol resorcinarene with long alkyl tailed-chains was determined to be efficient at stabilizing colloidal gold nanoparticles. The measurements of transmission electron microscopy (TEM) and ultraviolet–visible (UV–vis) spectra confirmed the formation of gold nanoparticles. The gold nanoparticles were synthesized by reducing HAuCl4 with NaBH4 in the presence of tetraaylthiol resorcinarene.

Bacillus subtilis is a preferred microbial host for the industrial production of nutraceuticals and a promising candidate for the synthesis of functional sugars, such as N-acetylglucosamine (GlcNAc). Previously, a GlcNAc-overproducer Bacillus subtilis SFMI was constructed using glmS ribozyme dual regulatory tool. Herein, we further engineered to enhance carbon flux from glucose towards GlcNAc synthesis. As a result, the increased flux towards GlcNAc synthesis triggered phosphosugar stress response, which caused abnormal cell growth. Unfortunately, the mechanism of phosphosugar stress response had not been elucidated in B. subtilis. In order to reveal stress mechanism and overcome its negative effect in bioproduction, we performed comparative transcriptome analysis. The results indicate that cells slow glucose utilization by repression of glucose import and accelerate catabolic reactions of phosphosugar. To verify these results, we overexpressed the phosphatase YwpJ, which relieved phosphosugar stress and allowed us to identify the enzyme responsible for GlcNAc synthesis from GlcNAc6P. In addition, the deletion of nagBB and murQ, responsible for GlcNAc precursor degradation, further improved GlcNAc synthesis. The best engineered strain, B. subtilis FMIP34, increased GlcNAc titer from 11.5 to 26.1 g/L in shake flasks and produced 87.5 g/L GlcNAc in 30-L fed-batch bioreactor. Our results not only elucidate, for the first time, the phosphosugar stress response mechanism in B. subtilis, but also demonstrate how the combination of rational metabolic engineering with novel insights into physiology and metabolism allows the construction of highly efficient microbial cell factories for the production of high value chemicals. This article is protected by copyright. All rights reserved.

Polymorphism is determined by the intrinsic molecular architecture designed via chemical synthesis and the external flow stimuli applied in practical processing. In this work, flow-induced crystall...

Driving behavior tracking and recognition are essential for traffic safety. This paper proposes a driving behavior monitoring and analysis method based on motion capture and artificial intelligence techniques. Different driving actions can be identified as normal or abnormal driving behaviors. The real-time motion is monitored by multiple miniature inertial measurement units (IMUs). Gradient descent method is used to fuse the raw data and update the driver’s attitude information constantly. The body’s joint angle series can be obtained by the iteration operation of the consecutive segment under the assumption of rigid structure. In order to accurately identify two arms’ maneuvers under different traveling routes, we compare the traditional machine learning-based method with the proposed deep neural network-based approach using joint angle series. The recognition rates of both methods are above 99% in the experiment, and the algorithm performance in real scenario is also satisfactory. These results show that joint angle-based driving behavior recognition is an effective method, and it can be applied for driving training or guiding the novice.

Different graphene oxide (GO) contents were chosen as the addition to prepare ZK30-xGO composites by selective laser melting (SLM). The microstructure and biodegradation of the SLMed ZK30-xGO composites were investigated. The results indicated that (i) SLM effectively produced a small grain size, (ii) the incorporation of GO into ZK30 caused a further decrease in grain size, and (iii) GO has a strong effect on the formation of the MgZn2 precipitates. The SLMed ZK30-0.6GO had the lowest biodegradation rate, which is attributed to the fact that the effect of the increased grain refinement and decreased amount of the MgZn2 precipitates counteracted the effect of the increased GO content on the biodegradation rate. Furthermore, the SLMed ZK30-xGO composites had good cytocompatibility. This work provided a novel approach to the composition design and fabrication of novel biodegradable GO reinforced Mg-based biomedical implants.

Enzyme clustering can improve catalytic efficiency by facilitating the processing of intermediates. Functional membrane microdomains (FMMs) in bacteria can provide a platform for enzyme clustering. However, the amount of FMMs at the cell basal level is still facing great challenges in multi-enzyme immobilization. Here, using the nutraceutical N-acetylglucosamine (GlcNAc) synthesis in Bacillus subtilis as a model, we engineered FMM components to improve the enzyme assembly in FMMs. First, by overexpression of the SPFH (stomatin-prohibitin-flotillin-HflC/K) domain and YisP protein, an enzyme involved in the synthesis of squalene-derived polyisoprenoid, the membrane order of cells was increased, as verified using di-4-ANEPPDHQ staining. Then, two heterologous enzymes, GlcNAc-6-phosphate N-acetyltransferase (GNA1) and haloacid dehalogenase-like phosphatases (YqaB), required for GlcNAc synthesis were assembled into FMMs, and the GlcNAc titer in flask was increased to 8.30 ± 0.57 g/L, which was almost three times that of the control strains. Notably, FMM component modification can maintain the OD600 in stationary phase and reduce cell lysis in the later stage of fermentation. These results reveal that the improved plasma membrane ordering achieved by the engineering FMM components could not only promote the enzyme assembly into FMMs, but also improve the cell fitness.

Treatment of [Pb(μ-SiPr)2]n with half equivalent of AgX (X = Cl, Br, I) in DMF afforded three new two-dimensional polymeric complexes {[Pb2(μ-SiPr)3]Cl}n (1), {[Pb2(μ-SiPr)3]Br}n (2) and [Pb2(μ-SiPr)3(μ-I)]n (3), while reaction of [Pb(μ-SiPr)2]n and equal equivalent of AgI gave a one-dimensional chain polymeric complex [Pb2(μ-I)2(μ-SiPr)2]n (4) with the Pb–(μ-I)2–Pb links. Interaction of 4 and two equivalents of NaS2CNMe2 afforded a bi-nuclear lead(II)-iodine complex [Pb(μ-I)(S2CNMe2)]2 (5) with chelated dimethyldithiocarbamate ligands. The structures of five lead(II)-halide complexes 1–5 with thiolate ligands were established by single-crystal X-ray crystallography. Two-dimensional polymeric complexes {[Pb2(μ-SiPr)3]Cl}n and {[Pb2(μ-SiPr)3]Br}n with the weak halogen bonds by balance halogen atoms (Cl, Br), a two-dimensional polymeric complex [Pb2(μ-SiPr)3(μ-I)]n with the Pb-I-Pb links, a one-dimensional chain polymer [Pb2(μ-I)2(μ-SiPr)2]n with the planar four-membered [Pb(μ-I)2Pb] and [Pb(μ-S)2Pb] rings, and a binuclear lead(II) complex [Pb(μ-I)(S2CNMe2)]2 with chelated dimethyldithiocarbamate ligands were reported.

Accurate values of masked detector signal (MDS) is the key to the correction capability of wavefront sensorless (WFSless) model-based adaptive optics (AO) system. However, imaging detectors always carry different kinds of noises in real applications, which make MDS deviate from theoretical results. Calculation errors of MDS suffered from the noise were analyzed through theory and simulation. Additionally, considering the method of threshold is usually used to mitigate the noise, we also discussed the influence of threshold on MDS. Results showed that the simulation is consistent with the theory and there exists an optimal threshold to make the error minimum for different noise. A fitting formula, which can accurately calculate optimal thresholds, was proposed based on the simulated data. Above results can provide a plausible method and theoretical basis to mitigate imaging noise of detectors in real applications.

The well-designed microbial cell factory finds wide applications in chemical, pharmaceutical, and food industries due to its sustainable and environmentally friendly features. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas) systems have been developed into powerful tools to perform genome editing and transcriptional regulation in prokaryotic and eukaryotic cells. Accordingly, these tools are useful to build microbial cell factories not only by reconstructing the genome but also by reprogramming the metabolic network. In this review, we summarize the recent significant headway and potential uses of the CRISPR technology in the construction of efficient microbial cell factories. Moreover, the future perspectives on the improvement and upgradation of CRISPR-based tools are also discussed.

Alkynes are among the most fundamentally important organic compounds and are widely used in synthetic chemistry, biochemistry, and materials science. Thus, the development of an efficient and sustainable method for the preparation of alkynes has been a central concern in organic synthesis. Cross-dehydrogenative coupling utilizing E-H and Z-H bonds in two different molecules can avoid the need for prefunctionalization of starting materials and has become one of the most straightforward methods for the construction of E-Z chemical bonds. This Review summarizes recent progress in the preparation of internal alkynes by cross-dehydrogenative coupling with terminal alkynes.

Three diisobutylaminomethylated calix[4]resorcinarenes 4–6 were synthesized by the condensation reaction of resorcinarenes 1–3 with diisobutylamine and an excess of formaldehyde. The crystals and supramolecular structures of compounds 4–6 were determined by single crystal X-ray diffraction along with proton nuclear magnetic resonance spectroscopy. The resorcinarene molecules occur in the crystal in the bowl-like form, are stabilized by a collar of exquisite intramolecular hydrogen bonding networks which all proceed in the same direction around the upper rim of the macrocycle. Four amino groups involved in intramolecular hydrogen bonding enlarge the intramolecular cavity of the resorcinarene, which form an encapsulating with “lid” over an included CH2Cl2 guest molecule. Adjacent molecules of compounds 4–6 connect through intermolecular hydrogen bonds, which rotated and localized to a staggered orientation in order to minimize the steric repulsion between them. Dichloromethane acts as the guest molecule for the self-assembly of diisobutyaminomethylated calix[4]resorcinarenes supramolecular structures.

For QSTE700 high-strength steel rectangular welded tube, the mechanical properties of the weld zone vary with the distance from the centerline of the weld. Therefore, the accurate description of constitutive relationship of the weld zone is of great significance for the study of formability of QSTE700 rectangular welded tube. Firstly, the mechanical properties of parent and mixed specimens containing weld zone and parent zone were obtained by uniaxial tensile test. And based on the microhardness test, the width and the microhardness distribution of the weld zone were determined. Secondly, by subdividing the weld zone into several small areas, and combining with the rule of mixtures and nanoindentation test, the continuous functional relationships of strength coefficient K, hardening coeffecient n and elastic modulus E were obtained, and then, the continuous constitutive relationship of QSTE700 rectangular welded tube was established. Finally, the validity and reliability of the continuous constitutive relationship of welded tube were verified by nanoindentation test and rotary draw bending of rectangular welded tube. Besides, it was found that the finite element model of rotary draw bending of QSTE700 rectangular welded tube established by using the continuous constitutive relationship can well simulate the cross section deformation and wall thickness variation.

This paper discusses the estimation of rice yield from Water Cloud Models (WCM) with different layers by a single X-band (8–12 GHz) Synthetic Aperture Radar (SAR) image, from a satellite named Terr...

Quinolone derivatives have attracted considerable attention due to their medicinal properties. This review covers many synthetic routes of quinolones preparation with their antibacterial properties. Detailed study with structure-activity relationship among quinolone derivatives will be helpful in designing new drugs in this field.

This paper studies testing of shifts in a time trend panel data model with serially correlated error component disturbances, without any prior knowledge of whether the error term is stationary or n...

Human motion mode detection is of great value in evaluating motor ability. In this study, a method of human motion mode detection based on an acceleration sensor was characterized. A human motion m...

Metabolic engineering is a key technology for cell factories construction by rewiring cellular resources to achieve efficient production of target chemicals. However, the existence of bottlenecks in synthetic pathway can seriously affect production efficiency, which is also one of the core issues for metabolic engineers to solve. Therefore, developing an approach for diagnosing potential metabolic bottlenecks in a faster and simpler manner is of great significance to accelerate cell factories construction. The cell-free reaction system based on cell lysates can transfer metabolic reactions from in vivo to in vitro, providing a flexible access to directly change protein and metabolite variables, thus provides a potential solution for rapid identification of bottlenecks. Here, bottleneck diagnosis of the N-acetylneuraminic acid (NeuAc) biosynthesis pathway in industrially important chassis microorganism Bacillus subtilis was performed using cell-free synthesis system. Specifically, a highly efficient B. subtilis cell-free system for NeuAc de novo synthesis was firstly constructed, which had a 305-fold NeuAc synthesis rate than that in vivo and enabled fast pathway dynamics analysis. Next, through the addition of all potential key intermediates in combination with substrate glucose respectively, it was found that insufficient phosphoenolpyruvate supply was one of the NeuAc pathway bottlenecks. Rational in vivo metabolic engineering of NeuAc-producing B. subtilis was further performed to eliminate the bottleneck. By down-regulating the expression level of pyruvate kinase throughout the growth phase or only in the stationary phase using inhibitory N-terminal coding sequences (NCSs) and growth-dependent regulatory NCSs respectively, the maximal NeuAc titer increased 2.0-fold. Our study provides a rapid method for bottleneck diagnosis, which may help to accelerate the cycle of design, build, test and learn cycle for metabolic engineering.

On December 27, 2018, the Beidou-3 System (BDS-3) has completed the deployment of 18 Medium Earth Orbit (MEO) satellites combined as a space constellation. In addition to the augmentation information for the new system signals B1C and B2a, the BDS-3 is compatible with the three augmentation information broadcast by the BDS-2 system for B1I and B3I signals: equivalent clock error correction, User Differential Ranging Error (UDRE) and Grid Ionosphere Vertical Error (GIVE). In this paper, the observation data of Beidou monitoring network are used to analyze the pseudo-range observation quality of the smooth transition signals B1I and B3I of BDS-2 and BDS-3. At the same time, the relationship between the equivalent clock error correction and the prediction error of the satellite clock is analyzed by using the Two-Way Satellite Time and Frequency Transfer (TWSTFT) data. The results show that the correlation between the equivalent clock error correction and the monitored clock error by using the TWSTFT data is greater than 60%. We calculate the UDRE by using the equivalent clock error correction. The results show that the satellite equivalent clock error correction can improve the accuracy of User Equivalent Range Error (UERE) by about 50%. This paper also compares the positioning accuracy of the BDS-2 satellites with the BDS-2 satellites combined BDS-3 satellites. The results show that the three-dimensional positioning accuracy is improved by about 30% after the BDS-3 satellites are added.

Two-step reactions of resorcin[4]arene (1) or methylresorcin[4]arene (2) with PPhCl2 and subsequent in situ oxidation with sulfur powder afforded a series of new thiophosphorylatocavitands 1a–1d or...

BaTi5O11 nanocrystals were synthesized by a hydrothermal method. The influence of Ba/Ti molar ratio in the Ba–Ti precursors on the morphology and dielectric properties of BaTi5O11 nanocrystals was investigated. In the precursors, the Ba2+ ion concentration was decreased from 0.02 to 0.01 mol/L, and the Ti4+ ion concentration was increased from 0.08 to 0.09 mol/L. The rice-like BaTi5O11 nanocrystals were synthesized at Ba/Ti molar ratios of 20:80 and 18:82, while the flower-like BaTi5O11 nanocrystals were formed at Ba/Ti molar ratios of 15:85, 12:88 and 10:90. The pure BaTi5O11 phase was synthesized at Ba/Ti molar ratio of 18:82 in the precursor, and the material had the permittivity of 38.9 at 8 GHz, which was close to that of the bulk BaTi5O11 ceramics.

The incorporation of the secondary co-units may not only change the kinetics and polymorphism of crystallization but also affect the melting behavior of polymers, leading to the memory effect even ...

The intrinsic coupling effect between the multiscale microstructure and macroscopic performance is a fundamental issue in polymer engineering and polymer physics. Combing the tensile testing and in...

Co-crystallization of C-propyl-pyrogallol[4]arene (PgC3) with 4,4′-bipyridine (bpy) in ethanol afforded a multi-component complex (PgC3) · 3(bpy) ·(EtOH) (1) that consists of a one-dimensional brick-wall framework, which was formed by four pyrogallol[4]arene molecules and two juxtaposed bpy molecules, entrapping two other bpy molecules as guests within each cavity. Heating a mixture of PgC3 and trans-1,2-bis-(4-pyridyl)ethylene (bpe) in an ethanol-water mixed solvent allowed the isolation of a multi-component complex (PgC3) ·(bpe) · 2(EtOH) ·(H2O) (2), which has a two-dimensional wave-like polymer structure with the bpe molecules embedded in the wave trough between two PgC3 molecules. Single-crystal X-ray crystallography was utilized to investigate the hydrogen bonding networks of the multi-component complexes 1 and 2.

Doxorubicin entrapped carbon dots (DOX-CDs) were prepared for bioimaging and enhanced intracellular drug delivery. The CDs were synthesized via the hydrothermal method using citrate and urea under 200 °C for 1 h. Then, DOX was successfully conjugated on the CDs via physicochemical interactions. The DOX-CDs exhibited good crystal structure, remarkable aqueous stability, excellent photoluminescence property, and a high quantum yield of 93%. The fluorescent images revealed that the DOX-CDs could be readily taken up by the cancer cells for cell labeling. Furthermore, endo-lysosomal pH-assisted DOX release behavior was observed from DOX-CDs, and the cytotoxicity of DOX-CDs was confirmed by the MTS assay against H0-8910 ovarian cancer cells. In addition, the CDs indicated bright fluorescent signal in the animal imaging test and demonstrated low toxicity after administration for 7 and 21 days. Therefore, the prepared CDs could be a promising imaging probe for biomedical imaging and intracellular drug delivery.

Insect gustatory system plays important roles in multiple behaviors including feeding, mating, and oviposition. Gustatory receptors (GRs), located on the dendritic membrane of gustatory sensory neurons (GSNs), are crucial in peripheral coding of non-volatile compounds. However, GRs and their detailed functions remain poorly understood in lepidopteran pests. In the present work, focusing on GR genes of Plutella xylostella, an important worldwide crop pest, we cloned a candidate fructose GR gene that has two spliced variants (PxylGR43a-1 and PxylGR43a-2), and determined the tissue expression profiles by semi-quantitative reverse transcription PCR (RT-PCR). It revealed that both GR variants were highly expressed in antennae and less highly in heads of adults, while PxylGR43a-2 was also weakly expressed in other tested tissues. Functional analyses were further conducted using the Xenopus oocyte system. PxylGR43a-1 and PxylGR43a-2 both responded specifically to the d-fructose among the 12 tested sugar compounds, but PxylGR43a-2 showed much higher current response than PxylGR43a-1. In addition, the proboscis extension reflex (PER) assay was conducted, demonstrating that female moths could respond to d-fructose following stimulation of antenna. Taken together, our study contributes to elucidation of the molecular mechanisms of fructose reception and provides a potential target for development of GR based pest control techniques.

New compounds with multiple anions are receiving increasing interest in view of their diverse structures and physical properties. Here we report four isostructural hexanary RE6Ta2MgQB8O26 (RE = Sm, Eu, Gd; Q = S, Se), belonging to the rare chalcogenide borates. Their structures feature an unprecedented [B4O10]8- unit comprised of one BO4 and three BO3 units. Their 3D structures are constructed by the connection between QRE6 octahedra and the ∞{[Mg(TaB4O13)2]16-} polyanionic layer. Density functional theory calculations on the electronic structure and a birefringence of 4 are also performed.

Lacto-N-neotetraose (LNnT), one of the oligosaccharides in human milk, has many beneficial effects on infant health. In a recent work, we have constructed a recombinant Bacillus subtilis strain for the production of LNnT. Here, we further improved LNnT production with a xylose-induced clustered regularly interspaced short palindromic repeats interference system. In particular, the expressions of pfkA and pyk genes in the Embden–Meyerhof–Parnas pathway module, zwf gene in the pentose phosphate pathway module, and mnaA gene in the teichoic acid synthesis module were downregulated. The LNnT titer was increased from 1.32 to 1.55 g/L. Furthermore, to improve the conversion efficiency of lacto-N-triose II to LNnT, we knocked out tuaD gene in branch pathway and improved the expression of lgtB gene, resulting in the further increase of LNnT titer to 2.01 g/L. Finally, the addition time and amount of inducer xylose were optimized, and LNnT titer reached 2.30 g/L in shake flask and 5.41 g/L in 3 L bioreactor.

The rubber tree, Hevea brasiliensis, produces natural rubber that serves as an essential industrial raw material. Here, we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-time sequencing (SMRT) and Hi-C technologies to anchor the ∼1.47-Gb genome assembly into 18 pseudochromosomes. The chromosome-based genome analysis enabled us to establish a model of spurge chromosome evolution, since the common paleopolyploid event occurred before the split of Hevea and Manihot. We show recent and rapid bursts of the three Hevea-specific LTR-retrotransposon families during the last 10 million years, leading to the massive expansion by ∼65.88% (∼970 Mbp) of the whole rubber tree genome since the divergence from Manihot. We identify large-scale expansion of genes associated with whole rubber biosynthesis processes, such as basal metabolic processes, ethylene biosynthesis, and the activation of polysaccharide and glycoprotein lectin, which are important properties for latex production. A map of genomic variation between the cultivated and wild rubber trees was obtained, which contains ∼15.7 million high-quality single-nucleotide polymorphisms. We identified hundreds of candidate domestication genes with drastically lowered genomic diversity in the cultivated but not wild rubber trees despite a relatively short domestication history of rubber tree, some of which are involved in rubber biosynthesis. This genome assembly represents key resources for future rubber tree research and breeding, providing novel targets for improving plant biotic and abiotic tolerance and rubber production.