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The present paper deals with the physiological response of the changes in chemical contents in the root, stem and leaf of Vetiveria zizanioides seedlings stressed by excess cadmium using Fourier transform infrared spectroscopy technique. Cadmium accumulation in plant and distribution in subcellular by atomic absorption spectroscopy were tested under different concentrations cadmium stress. The results show that low cadmium concentrations (

Energy and environmental issues are becoming more and more severe and renewable energy storage technologies are vital to solve the problem. Rechargeable metal (Li, Na, Mg, Al)-sulfur batteries with low-cost and earth-abundant elemental sulfur as the cathode are attracting more and more interest for electrical energy storage in recent years. Lithium-sulfur (Li-S), room-temperature sodium-sulfur (RT Na-S), magnesium-sulfur (Mg-S) and aluminum-sulfur (Al-S) batteries are the most prominent candidates among them. Many obvious obstacles are hampering the developments of metal-sulfur batteries. Li-S and Na-S batteries are encumbered mainly by anode dendrite issues, polysulfides shuttle and low conductivity of cathodes. Mg-S and Al-S batteries are short of suitable electrolytes. In this review, relationships between various employed nanostructured materials and electrochemical performances of metal-sulfur batteries have been demonstrated. Moreover, the selections of suitable electrolytes, anode protection, separator modifications and prototype innovations are all crucial to the developments of metal-sulfur batteries and are discussed at the same time. Herein, we give a review on the advances of Li-S, RT Na-S, Mg-S and Al-S batteries from the point of view of materials, and then focus on perspectives of their future developments.

Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields (32%–91%). In addition, a gram-scale reaction, late-stage modification of drug, synthetic transformation of the product, and further application of the catalytic strategy were also performed. Preliminary studies indicate that the reaction undergoes a radical process.

Future climate projections made with high-resolution climate models carry the promise of bridging the gap between weather and climate scales, but the scientific and technical hurdles remain daunting. New simulations carried out on Frontera by a team of climate scientists and software engineers are yielding novel insights into how anthropogenic climate change will impact weather extremes at regional scales over the course of the twenty-first century.

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is native to the Americas. It has rapidly invaded 47 African countries and 18 Asian countries since the first detection of invasion into Nigeria and Ghana in 2016. It is regarded as a super pest based on its host range (at least 353 host plants), its inherent ability to survive in a wide range of habitats, its strong migration ability, high fecundity, rapid development of resistance to insecticides/viruses and its gluttonous characteristics. The inherently superior biological characteristics of FAW contribute to its invasiveness. Integrated pest management (IPM) of FAW has relied on multiple applications of monitoring and scouting, agricultural control, chemical pesticides, viral insecticides, sex attractants, bio-control agents (parasitoids, predators and entomopathogens) and botanicals. Knowledge gaps remain to be filled to: (1) understand the invasive mechanisms of S. frugiperda; (2) understand how to prevent its further spread and (3) provide better management strategies. This review summarizes the biological characters of FAW, their association with its invasiveness and IPM strategies, which may provide further insights for future management.

On the eve of the occurrence of geological hazards, part of the rock and soil body begins to burst, rub, and fracture, generating infrasound signals propagating outward. 3D advanced positioning of the landslide has remained unsolved, which is important for disaster prevention. Through the Fourier transform and Hankel transform of the wave equation in cylindrical coordinates, this work established a three-dimensional axisymmetric sound field model based on normal waves, and designed a 4-element helix triangular pyramid array with vertical and horizontal sampling capabilities. Based on this, the three-dimensional matching localization algorithm of infrasound for geological hazards is proposed. Applying the algorithm to the infrasound signal localization of rock and soil layers, it was found that the helix triangular pyramid array can achieve accurate estimation of depth and distance with a smaller number of array elements than the traditional array, and may overcome the azimuth symmetry ambiguity. This study shows the application prospects of this method for predicting geohazards position several hours in advance.

Guidepost-based navigation system is a novel autonomous orbit determination method for the GEO satellite. The system is achieved by using the camera imaging function to obtain the guidepost images and the GNSS signal receiver to obtain the pseudoranges between the GEO and the navigation satellites. Due to the high altitude of GEO satellite and the time-varying sunlight condition in the space environment, it may be difficult to obtain object image points and the distance measurements of GNSS because of the weak visibility of the guideposts. To deal with the problem, a novel integrated orbit determination system is presented. The Earth landmarks, the in-orbit spacecraft and GNSS navigation satellites whose line-of-sights and the distance can be easily obtained are used at the same time as information for the GEO satellite navigation based on the observability conditions analysis. The observability of the GEO satellite navigation system is analyzed through the physical observability, the mathematical observability and the engineering observability through the observing geometry, the rank of observability matrix and the Cramer-Rao lower bound (CRLB) respectively. Besides, the maximum correntropy unscented Kalman filter (MCUKF) algorithm is applied to improve the estimation stability of the system in the presence of non-Gaussian noises. The simulation indicates the feasibility of the proposed scheme.

A mechanochemical method was employed to prepare modified iron molybdate catalysts with various metal salts as precursors. The physicochemical properties of the iron molybdate catalysts were characterized, and their performances in catalyzing the reaction from methanol to formaldehyde (HCHO) were evaluated. Iron molybdate catalysts doped with Co(NO3)2 · 6H2Oand Al(NO3)3 · 9H2O resulted in high HCHO yields. Compared with a commercial catalyst, the HCHO yields in the reaction with the modified catalyst at an optimal Co/Mo molar ratio reached 97.37%. According to chemical state analysis, the formation of CoO and the efficient decrease in the MoO3 sublimation rate could be important factors enhancing the HCHO yield in reactions catalyzed with iron molybdate doped with different Co/Mo mole ratios.

Quercus L. has significant societal, ecological and economic benefits in the Northern Hemisphere. However, species identification among oaks is notoriously difficult. China harbours highly diverse oaks, of which the diversity of white oaks is the most extensive; however, to date, the evolution of chloroplast (cp) genomes in white oaks in China has not been comprehensively studied. Thus, we sequenced the complete cp genomes (161,254 bp, 161,229 bp and 161,254 bp in size) of three white oak species (Quercus serrata Thunb. var. brevipetiolata A. DC. Nakai, Quercus wutaishansea Mary and Quercus mongolica Fischer ex Ledebour, respectively). Six white oak species (Quercus aliena Blume, Quercus dentata Thunb., Quercus aliena Blume var. acutiserrata Maximowicz ex Wenzig, Q. serrata var. brevipetiolata, Q. wutaishanica and Q. mongolica) and five other Fagaceae species (Quercus rubra L., Quercus variabilis Bl., Quercus aquifolioides Rehd. et Wils., Fagus engleriana Seem. and Castanea henryi Skan Rehd. et Wils.) were retrieved for comparative analyses. We detected 11 highly divergent regions (psbA, matK/rps16, rps16, trnS-GCU/trnG-GCC, trnR-UCU/atpA, trnT-GGU/psbD, ndhJ, ndhJ/ndhK, accD, ndhF and ycfI) through comparative analyses and these regions might be used as molecular markers. The ω ratio of the rps12, rpoC2 and ycf1 genes was greater than 1 in several comparison groups between white oaks and the petA gene was subjected to significant positive selection between the comparison of six white oaks and Q. variabilis. Phylogenetic analyses revealed that six white oaks were grouped with Q. rubra, forming a single clade.

Polymer-based nanocomposites with high dielectric constant have attracted the attention of many researchers, owing to their wide applications in advanced electronics. The experimental measurement of dielectric constant for every polymer-based nanocomposite system is not practically feasible, due to there being many polymer matrixes and nanofiller combinations. Therefore, there is rising interest in predicting the dielectric constant of polymer nanocomposites, using mathematical methods. In this study, we estimate the dielectric constant of polymer nanocomposites by considering astounding interphase properties. The Paletto model is modified, in order to predict the dielectric constant of a BaTiO3–polymer nanocomposite by properly assuming the interphase parameters, including the thickness of the interphase layer and the dielectric constant of the interphase region. Results from the modified Paletto model are verified by experimental data, indicating that the predicted values agree well with the experimentally determined dielectric constant, and thus the accuracy of the developed model. In addition, the particle concentration will significantly be underestimated if the influence of the interphase volume is ignored. Furthermore, the effects of different parameters, including the dielectric constant of polymer substrate, dielectric constant of particles, particle content, particle size, the thickness of the interphase layer as well as the dielectric constant of the interphase region on the dielectric constant of a BaTiO3–polymer nanocomposite are also investigated. The developed model provides a useful tool for predicting the dielectric constant of a BaTiO3–polymer nanocomposite, accompanied by interphase analysis.

Unadorned carbon nitride was synthesized via different nitrogen-rich precursors by thermal polymerization and applied to multifungicides for simultaneous photodegradation in the present study. Urea-derived carbon nitride (UCN) was verified to be most efficient in fungicide removal. The influences of catalyst dosage and pH were studied during the photodegradation process. Hydroxyl radical (•OH) and holes (h+) are the active species during photodegradation of each of the eight fungicides within an aqueous environment. The primary photodegradation products and pathways of all eight fungicides were systematically identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. In addition, the UCN catalyst was also applied to potted plants. The experimental results revealed that UCN could reduce fungicide residues in plants grown within a contaminated matrix. This study shows promising applications of the UCN catalyst in alleviating the hazards of pesticide residue.

Ononin is a bioactive isoflavone of legumes. To explore the "effective forms" of ononin, its metabolites were characterized using HPLC-ESI-IT-TOF-MSn after oral administration to rats. Metabolites (106), including 94 new metabolites, were characterized, which contained 17 phase I, 23 hydroxylated and methylated, 54 sulfated, 10 glucuronidated, and 2 sulfated and glucuronidated metabolites. Six hydroxylated metabolites of formononetin (aglycone of ononin) were simultaneously detected for the first time. Twenty-three hydroxylated and methylated metabolites were the new metabolites of ononin, and the number of hydroxylation and methylation was 1-3 and 1-2. Twenty metabolites have ononin-related bioactivities, and many metabolites have the same bioactivities. Their probable mechanisms of action may be additive and/or synergistic effects, especially because of the addition of the blood concentrations of these compounds. The results provide a foundation for a better understanding of the "effective forms" of ononin.

The melamine fiber has been widely used because of its excellent flame retardancy. We tried to fabricate melamine fibers using ionic liquids (ILs) as solvents, melamine formaldehyde resin prepolyme...

Statistical prediction of tropical sea surface temperatures (SSTs) is performed using linear inverse models (LIMs) that are constructed from both observations and general circulation model (GCM) output of SST. The goals are to establish a baseline for tropical SST predictions, to examine the extent to which the skill of a GCM-derived LIM is indicative of that GCM’s skill in forecast mode, and to examine the linkages between mean state bias and prediction skill. The observation-derived LIM is more skillful than a simple persistence forecasts in most regions. Its skill also compares well with some GCM forecasts except in the equatorial Pacific, where the GCMs are superior. The observation-derived LIM is matched or even outperformed by the GCM-derived LIMs, which may be related to the longer data record available for GCMs. The GCM-derived LIMs provide a fairly good measure for the skill achieved by their parent GCMs in forecast mode. In some cases, the skill of the LIM is actually superior to that of its parent GCM, indicating that the GCM predictions may suffer from initialization problems. A weak-to-moderate relation exists between model mean state error and prediction skill in some regions. An example is the eastern equatorial Atlantic, where an erroneously deep thermocline reduces SST variability, which in turn affects prediction skill. Another example is the equatorial Pacific, where skill appears to be linked to cold SST biases in the western tropical Pacific, which may reduce the strength of air–sea coupling.

Enrofloxacin (EFX) was selected as the medicinal ligand to afford a new copper(ii)-based complex, EFX-Cu, which was structurally characterized by spectroscopic analyses including X-ray single crystal diffraction. It was also stable and could retain the coordination state in aqueous solution. The in vitro antibacterial activity of EFX-Cu against a panel of pathogenic bacteria was about the same as that of EFX, except that it was twice as active against E. coli. The in vivo test on mice gave a LD50 value of 8148 mg kg−1 for EFX-Cu, which was much lower than those for EFX (LD50, 5312 mg kg−1) and its clinically used sodium salt, EFX-Na (LD50, 1421 mg kg−1). In addition, no obvious lesions in the organs of the dead mice were found by histopathological examination. Pharmacokinetic studies on rats suggested similar pharmacokinetics between EFX-Cu and EFX. On the other hand, EFX-Cu showed higher acute toxicity than EFX-Na in zebrafish, which was inconsistent with that in mice. The ROS-related inflammation and anti-inflammatory assay of EFX-Cu, respectively, in normal cells and zebrafish could be ascribed to its ROS-related redox property. Unfortunately, the final in vivo therapeutic assay in the E. coli-infected mouse model indicated that the therapeutic effect of EFX-Cu, mainly in terms of mortality in mice, was found to be lower than that of EFX-Na at the same dosage (800 mg kg−1, continuous gavage), although the contradictory factors between toxicity and antibacterial activity could not be excluded in this trial.

For simulating the hot deformation behavior of a powder metallurgy nickel-base superalloy during isothermal forging, the hot compression tests were performed in the temperatures of 1020-1110 °C with the strain rates from 10−3 to 1 s−1. The thermoplastic deformation and dynamic recrystallization (DRX) behavior of the superalloy during thermocompression were systematically studied. It can be shown that the flow stress of the superalloy exhibits apparent characteristics of DRX. A relationship indicating the dependency of flow stress on deforming temperature and strain rates is built through introducing the Z parameter. The work-hardening rate (θ) curves of the superalloy at various deformation conditions are obtained, and the values of θ are found to decrease with decreasing Z parameter, i.e., decreasing strain rates and increasing deforming temperature. There exists a power exponential relationship between critical strain ec and Z parameter. Combining the experimental data, a two-stage constitutive model on the basis of the Estrin–Mecking constitutive model and the DRX kinetic model is set up to model the flow stress of the superalloy. The flow stresses obtained from the established model are well consistence with the measured values.

During metro construction, unidentified cavities pose a serious threat to the integrity of the tunnels and public safety. An efficient and accurate cavity‐detection method is needed, given the limited space and time constraints of urban construction. Equivalent offset migration is a high‐accuracy, seismic scattered‐wave imaging method that is effective in wavefield extraction, has the ability to derive the wavefield outside the range of the source–receiver points and can use imaging data for areas with poor signal‐to‐noise ratios. In this study, we consider a stratified subsurface structure and the geological conditions of a city and construct a typical urban cavity geological model to study the characteristics of cavity‐scattered waves. In numerical studies, equivalent offset migration is superior to Kirchhoff post‐stack migration in the case of seismic scattered‐wave imaging. A fast‐moving detection device for urban construction conditions is designed to meet the data‐acquisition requirements on the basis of the scattered‐wave characteristics and equivalent offset migration method. Efficient acquisition and accurate detection are confirmed, with the detected depth deviating by less than 1 m compared to the depth obtained from borehole checks along the Xuzhou Metro Line 1 in China. The results show that cavity detection using seismic scattered waves can meet urban engineering requirements. Further study on the design of a high‐performance detection device, reception and extraction of weakly scattered waves, and scattered‐wave recognition and interpretation techniques for different targets will be helpful in solving cavity‐detection problems in urban engineering.

Mitogen-activated protein kinase 3 (MAPK3) is involved in plant growth and development, as well as response to adverse stress. Here we aimed to explore the role of StMAPK3 in response to salt and osmosis stress. Polyethylene glycol (PEG) (5% and 10%) and mannitol (40 mM and 80 mM) were used to induce osmosis stress. To induce salinity stress, potato plant was cultured with NaCl (40 mM and 80 mM). StMAPK3 overexpression and RNA interference-mediated StMAPK3 knockdown were constructed to explore the role of StMAPK3 in potato growth, stomatal aperture size, activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), and contents of H2O2, proline and malonaldehyde (MDA). Meanwhile, we detected transpiration, net photosynthesis, stomatal conductance, and water use efficiency. Subcellular location of StMAPK3 protein was also detected. PEG, mannitol and NaCl treatments induced the accumulation of StMAPK3 mRNA in potato plants. StMAPK3 protein was located on the membrane and nucleus. Abnormal expression of StMAPK3 changed potato phenotypes, enzyme activity of SOD, CAT and POD, as well as H2O2, proline and MDA contents under osmosis and salinity stress. Photosynthesis and stomatal aperture were regulated by StMAPK3 in potato treated by PEG, mannitol and NaCl. Modulation of potato phenotypes and physiological activity indicates StMAPK3 as a regulator of osmosis and salinity tolerance.

C3H zinc finger transcription factors play important roles in managing various biotic/abiotic stresses in Aarabidopsis, rice, and maize. The functions of these factors in wheat, however, remain largely unclear. We identified 88 TaC3H genes that were divided into four subfamilies in this analysis. Gene structure and conserved domain analyses indicate that most members of the same subfamily have similar structures. A total of 76 paralogous and 48 orthologous pairs were identified and Ka/Ks values were used to analyze replication relationships amongst wheat, rice, and Arabidopsis. Gene ontology (GO) annotation analysis showed that most TaC3H genes possessed molecular functions, while transcriptome results showed that the 88 TaC3H genes responded to water imbibition. Microarray data for 53 TaC3H genes were obtained and heat maps were generated; these results indicate that these genes are expressed in 13 wheat tissues. Subcellular localization prediction analysis indicates that most TaC3H genes are located in the nucleus. Promoter analysis indicates that most TaC3H genes contained cis-elements including ABRE, GARE-motif, and MBS, indicating that these can respond to various biotic/abiotic stresses. Transcriptome data and quantitative real-time PCR analysis of wheat cultivars with contrasting seed dormancy phenotypes show that five genes TaC3H4/-18/-37/-51/-72 were very likely involved in seed dormancy and germination. Exogenous ABA treatment further indicated that these five genes were responsive to ABA, suggesting that there may be a crosstalk between these genes and ABA signaling pathway in controlling seed dormancy and germination. These results provide a theoretical basis for subsequent studies on TaC3H gene function and also contribute to studies on the C3H gene in other species.

Insects are poikilothermic animals, and temperature is one of the most important abiotic factors affecting their spread and distribution. For example, differences in thermal tolerance may underlie the significant differences in geographical distributions between the native AsiaII3 and invasive MED (Mediterranean) cryptic Bemisia tabaci species in China. Transient receptor potential (TRP) channels are key components of the insect temperature perception system and act as molecular thermometers since they can be activated by specific changes in temperature. In this study, we cloned and characterized the AsiaII3 BtTRP gene and revealed its functions in the response to thermal stress. The full-length cDNA of BtTRP was 3821 bp, with a 3501-bp open reading frame encoding a 132.05-kDa protein. Comparing the deduced amino acid sequences of AsiaII3 BtTRP and MED TRP revealed five amino acid differences. In situ hybridization indicated that BtTRP might be widely expressed throughout the AsiaII3 adult body. BtTRP mRNA expression reached the highest levels after exposure to mild thermal stimuli (12 and 35°C), showing that BtTRP expression can be induced by temperature stress. Furthermore, the thermal tolerance of AsiaII3 after BtTRP dsRNA feeding was significantly lower than that of the control. Taken together, the present study highlights the importance of TRP channels for B. tabaci thermal resistance, and allows us to infer that the differences in amino acids between AsiaII3 and MED might cause the differences in thermal tolerance of these two cryptic species. This study provides a new direction for investigating geographic distribution differences between invasive and native insects.

To study the hot deformation behavior of a new powder metallurgy nickel-based superalloy, hot compression tests were conducted in the temperature range of 1020–1110 °C with the strain rates of 0.001–1 s−1. It is found that the flow stress of the superalloy decreases with increasing temperature and decreasing strain rate. An accurate constitutive equation is established using a hyperbolic-sine type expression. Moreover, processing map of the alloy is constructed to optimize its hot forging parameters. Three domains of dynamic recrystallization stability and instability regions are identified from the processing map at a strain of 0.7, respectively. The adiabatic shear band, intergranular crack and a combination of intergranular crack and wedge crack are demonstrated to be responsible for the instabilities. Comprehensively analyzing the processing map and microstructure, the optimal isothermal forging conditions for the superalloy is determined to be t=1075–1105 °C and =10−3–10−2.8 s−1.

Aim: Smart mesoporous silica nanoparticles (MSNs) coated with carbon dots (CDs) and poly(N-vinylcaprolactam) (PNVCL) as a mixed shell (CDs/PNVCL polymer grafted MSNs) were prepared for pH-trigged anticancer drug release and real-time monitoring. Materials & methods: The amino-terminated PNVCL and amino-rich CDs were grafted onto the surface of aldehyde group functionalized MSNs through Schiff base reaction. Doxorubicin (DOX) was loaded into the prepared nanoparticles. Results: DOX could be quickly released in the tumor environment, leading to cell apoptosis. The linear fit between the percentage of released DOX and the fluorescence intensity of CDs indicated that the change in fluorescence intensity could be used to monitor drug release in real time. Conclusion: The as-prepared CDs/PNVCL polymer grafted MSNs are promising candidates for integrating controllable release and real-time monitoring in cancer treatment.

A phytochemical study on the aerial parts of Leonurus japonicus led to the isolation and identification of 38 labdane diterpenoids, including 18 new (1, 2, 11, 12, 16-21, 24, 30-34, 37, 38) and 20 known (3-10, 13-15, 22, 23, 25-29, 35, 36) analogues. Their structures were elucidated based on physical data analysis, including 1D and 2D NMR, HRMS, UV, IR, and X-ray diffraction. The structure of the known compound 4 was confirmed by single-crystal X-ray diffraction data. These compounds can be divided into furanolabdane (1-10), tetrahydrofuranolabdane (11-15), lactonelabdane (16-23), labdane (24-29), and seco-labdane (30-38) type diterpenoids. All compounds were screened by lipopolysaccharide (LPS)-induced nitric acid (NO) production in RAW264.7 cells to evaluate anti-inflammatory effects. Compounds 1, 5, 10-13, 16-19, 31-33, and 38 inhibited NO production with IC50 values lower than 50 μM, with compound 30 being the most active, with an IC50 value of 3.9 ± 1.7 μM. Further studies show that compound 30 inhibits pro-inflammatory cytokine production and IKK α/β phosphorylation and restores the IκB expression levels in the NF-κB signaling pathway.

The high specific capacity and energy density of lithium–sulfur batteries have attracted strong considerations on their fundamental mechanism and energy applications. However, polysulfide shuttle is still the key issue that impedes the development of Li–S batteries. Exploring nanocrystal hosts for polysulfide immobilization and conversion is a promising way. In this contribution, we have investigated well-dispersed Co9S8 nanocrystals grown on graphene oxide (GO) nanosheets with different degrees of dispersion as cathode host materials for Li–S batteries. The Co9S8-GO composite with 1 wt% GO (GCS1) has an average crystal size of 76 nm and shows the strongest adsorption capability toward lithium polysulfides. When used as the host material for the cathode of Li–S batteries, the GCS1-sulfur composite exhibits an initial specific capacity of ~1000 mAh g−1 at 0.5 C and shows an average decay rate of 0.11% for 500 cycles. This work on the dispersion control of Co9S8 nanocrystals may inspire more investigations on well-dispersed nanocrystal based hosts for Li–S batteries.

Summary All aerial epidermal cells in land plants are covered by the cuticle, an extracellular hydrophobic layer that provides protection against abiotic and biotic stresses and prevents organ fusion during development.Genetic and morphological analysis of the classic maize adherent1 (ad1) mutant was combined with genome‐wide binding analysis of the maize MYB transcription factor FUSED LEAVES1 (FDL1), coupled with transcriptional profiling of fdl1 mutants.We show that AD1 encodes an epidermally‐expressed 3‐KETOACYL‐CoA SYNTHASE (KCS) belonging to a functionally uncharacterized clade of KCS enzymes involved in cuticular wax biosynthesis. Wax analysis in ad1 mutants indicates that AD1 functions in the formation of very‐long‐chain wax components. We demonstrate that FDL1 directly binds to CCAACC core motifs present in AD1 regulatory regions to activate its expression. Over 2000 additional target genes of FDL1, including many involved in cuticle formation, drought response and cell wall organization, were also identified.Our results identify a regulatory module of cuticle biosynthesis in maize that is conserved across monocots and eudicots, and highlight previously undescribed factors in lipid metabolism, transport and signaling that coordinate organ development and cuticle formation.

Triplet energy transfer from inorganic nanocrystals to molecular acceptors has attracted strong attention for high-efficiency photon upconversion. Here we study this problem using CsPbBr3 and CdSe nanocrystals as triplet donors and carboxylated anthracene isomers as acceptors. We find that the position of the carboxyl anchoring group on the molecule dictates the donor-acceptor coupling to be either through-bond or through-space, while the relative strength of the two coupling pathways is controlled by the wavefunction leakage of nanocrystals that can be quantitatively tuned by nanocrystal sizes or shell thicknesses. By simultaneously engineering molecular geometry and nanocrystal wavefunction, energy transfer and photon upconversion efficiencies of a nanocrystal/molecule system can be improved by orders of magnitude.

Developing hydrogen evolution reaction (HER) electrocatalysts with high activity, durability and moderate price is essential for sustainable hydrogen energy utilization. Here, the facile coupling of carbon dots (CDs, 0D carbon materials) and carbon fibres (CFs, 1D carbon materials) for enhanced electrochemical hydrogen production was demonstrated. Electrochemical tests revealed that the CD/CF catalysts showed outstanding catalytic activity with a small overpotential of 280 mV at the current density of 10 mA cm-2 , a small Tafel slope of 87 mV dec-1 and prominent durability. Percolation theory was for the first time introduced to interpret the catalytic mechanism of the CD/CF catalysts. The special morphology assembled by the 0D carbons constituted the percolating clusters and promoted electron transport throughout the 1D carbons. The strategy and theory can be adapted to general electrocatalytic applications for achieving and interpreting precise tuning on highly efficient electron transfer in electrocatalysts.

Room-temperature manipulation and processing of information encoded in the electronic valley pseudospin and spin degrees of freedoms lie at the heart of the next technological quantum revolution. In atomically thin layers of transition-metal dichalcogenides (TMDs) with hexagonal lattices, valley-polarized excitations and valley quantum coherence can be generated by simply shining with adequately polarized light. In turn, the polarization states of light can induce topological Hall currents in the absence of an external magnetic field, which underlies the fundamental principle of opto-valleytronics devices. However, demonstration of optical generation of valley polarization at room temperature has remained challenging and not well understood. Here, we demonstrate control of strong valley polarization (valley quantum coherence) at room temperature of up to ∼50% (∼20%) by strategically designing Coulomb forces and spin-orbit interactions in atomically thin TMDs via chalcogenide alloying. We show that tailor making the carrier density and the relative order between optically active (bright) and forbidden (dark) states by key variations on the chalcogenide atom ratio allows full control of valley pseudospin dynamics. Our findings set a comprehensive approach for intrinsic and efficient manipulation of valley pseudospin and spin degree of freedom toward realistic opto-valleytronics devices.

Betalains are emerging natural pigments with high tinctorial strength and stability, physiological activities, and fluorescent properties for potential application in food, cosmetic, and pharmaceutical industries. Betalains including yellow betaxanthins and red betacyanins are mainly restricted in the Caryophyllales plants. To expand the availability of individual betaxanthins, here, we constructed an Escherichia coli BTA6 for de novo biosynthesis of betalamic acid. Using this strain as a monoculture platform, 14 yellow and 2 red betaxanthins were produced by feeding amino acids and amines. Furthermore, we constructed an l-histidine overproducing strain using chromosome engineering to deattenuate regulation and established a coculture system. After optimization of the initial inoculation ratios and fermentation conditions, the compatible and robust coculture system produced 287.69 mg/L of histidine-betaxanthin. This is the first report on de novo production of betaxanthins in engineered E. coli using glucose as a carbon source. Our work highlights the feasibility of microbial cell factories to produce individual betalains.

Tuta absoluta (Meyrick) originated in South America and is one of the most serious pests of tomatoes. It is also known to attack other solanaceous crops, including potato, eggplant, pepper, tobacco, and weedy species such as black nightshade. After accidental introduction into Spain in 2006, this pest spread rapidly throughout Afro-Eurasia and has become a major threat to tomato production worldwide. Here, we report the first record of T. absoluta as an invasive pest in China. It was found in tomato fields in Ili Kazakg Autonomous Prefecture, Xinjiang Uygur Autonomous Region (Ili, Xinjiang), China, and its occurrence was confirmed by both morphological and molecular approaches. In Ili, T. absoluta has been found to attack eggplant, potato, and black nightshade. We found the larvae generally mining and feeding on leaves and boring into tomato fruits, with multiple larvae sometimes observed in a single fruit. Its infestation levels differ among the tomato fields and host species. In all of the surveyed tomato fields, T. absoluta infested 100% of plants. In some of the fields, up to 90% of the eggplant and 100% of the potato plants were infested. Since no natural enemies were found under field conditions, suitable management practices are urgently needed to stop the further spread of this destructive pest in China.

Topological materials support robust quantum states. Recent experiments demonstrate the topologically induced spin-polarized Majorana-type end state and boundary state in S-type armchair graphene nanoribbons (A-GNRs). Here, we report the topologically induced spin-polarized interface states in the topological GNRs constructed by alternating trivial armchair-edged GNR and nontrivial cove-edged GNR (C-GNR) segments (A/C-GNRs) from first-principles calculations. Distinct from spin-polarized states observed in zigzag GNRs, chiral GNRs, and S-type A-GNRs, the spin-polarized states in A/C-GNRs have the net spin distributed on the boundary region with antiferromagnetic coupling between opposite interfaces, the calculated magnetic moment is about 2 μB in integer, and the Curie temperature is high to 350 K. The universality has been evaluated. It is revealed that the topological phase is responsible for such interface magnetism. Hence, our findings provide obvious evidence for topologically induced spin-polarized interface states, which can enrich the knowledge of GNR-based magnetism and have promising applications featured by the robustness.

Triplet energy transfer from colloidal nanocrystals is a novel approach to sensitizing molecular triplets that are important for many applications. Recent studies suggest that this triplet transfer can be mediated by a hole transfer process when it is energetically allowed. In contrast, electron-transfer-mediated triplet transfer has not been observed yet, which is likely due to hole-trapping in typical II-VI group nanocrystals inhibiting the hole transfer step following initial electron transfer and hence disrupting a complete triplet exciton transfer. Here we report electron-transfer-mediated triplet energy transfer from CsPbCl3 and CsPbBr3 perovskite nanocrystals to surface-anchored rhodamine molecules. The mechanism was unambiguously established by ultrafast spectroscopy; control experiments using CdS nanocrystals also confirmed the role of hole-trapping in inhibiting this mechanism. The sensitized rhodamine triplets engaged in a variety of applications such as photon upconversion and singlet oxygen generation. Compared to conventional one-step triplet transfer, the electron-transfer-mediated mechanism is less demanding in terms of interfacial electronic coupling and hence is more generally implementable. Overall, this study not only establishes a complete framework of triplet energy transfer across nanocrystal/molecule interfaces but also greatly expands the scope of molecular triplet sensitization using nanocrystals.

Triarylmethanes are important molecules in organic chemistry. This review discusses advances in their synthesis summarized in five categories according to the starting materials: (1) benzyl reagents with different leaving groups, such as benzyl alcohols, ethers, esters, phosphates, sulfones, thioethers, sulfonamide, 1,3-dicarbonyls, and ammonium salts; (2) reactions via para- or ortho-quinone methides; (3) arylation of benzyl halides; (4) C–H activation of methylenes; and (5) reactions of aldehydes or N-tosylhydrazones. Triarylmethane derivatives such as 9-arylxanthenones, 9-arylfluorenes, and aryloxepines are also discussed.1 Introduction2 Benzyl Reagents with Leaving Groups3 Quinone Methide Mediated Reactions4 Arylation of Benzyl Halides5 C–H Activation of Methylene6 Reactions of Carbonyl Compounds7 Conclusions

Immediately after the demonstration of the high-quality electronic properties in various two dimensional (2D) van der Waals (vdW) crystals fabricated with mechanical exfoliation, many methods have been reported to explore and control large scale fabrications. Comparing with recent advancements in fabricating 2D atomic layered crystals, large scale production of one dimensional (1D) nanowires with thickness approaching molecular or atomic level still remains stagnant. Here, we demonstrate the high yield production of a 1D vdW material, semiconducting Ta2Pd3Se8 nanowires, by means of liquid-phase exfoliation. The thinnest nanowire we have readily achieved is around 1 nm, corresponding to a bundle of one or two molecular ribbons. Transmission electron microscopy (TEM) and transport measurements reveal the as-fabricated Ta2Pd3Se8 nanowires exhibit unexpected high crystallinity and chemical stability. Our low-frequency Raman spectroscopy reveals clear evidence of the existing of weak inter-ribbon bindings. The fabricated nanowire transistors exhibit high switching performance and promising applications for photodetectors.

Hot compression tests of a FGH96 superalloy under the conditions of temperatures from 1020 to 1110 °C and strain rates from 10−3 to 1 s−1 were carried out on a Gleeble-3180D thermo simulator. The microstructure evolution and nucleation mechanisms of dynamic recrystallization (DRX) for the superalloy were analyzed by electron backscatter diffraction (EBSD) technique and transmission electron microscope (TEM). A DEFORM-3D Finite Element (FE) software was used to simulate the distributions of deformation and microstructures of the compressed specimens. The results show that the flow stress curves of FGH96 superalloy exhibit typical features of dynamic recrystallization (DRX). The constitutive equation is established based on the friction-corrected flow stress data. Increasing temperature or decreasing strain rate is found to result in the increases of both the DRX fraction and the grain size. The nucleation mechanisms of DRX for the superalloy mainly include dominant discontinuous dynamic recrystallization (DDRX) and assisting nucleation by twins. The prediction models of DRX, which are expressed as a function of Z parameter, are obtained on the basis of the compression data and quantitatively microstructural characterization. By comparing the simulated results with that of the experiment, the accuracy of the developed DRX models is validated.

Mechanochemical method has applied to the green preparation of iron-molybdenum catalyst efficiently, and their catalytic performance was evaluated by the oxidation of methanol to formaldehyde. In order to investigate the formation process of iron-molybdenum catalyst based on mechanochemical method, various characterization techniques have been employed. Results indicate that iron-molybdenum catalyst could not be generated during ball milling process without calcining, and calcination is crucial step to regulate the ratio of MoO3 and Fe2(MoO4)3. For the formation of MoO3 and Fe2(MoO4)3 phase, 180 °C could be the key turning temperature point. Fe2(MoO4)3 and MoO3 phases are concurrently emerged when Mo/Fe atomic ratio exceeds 1.5. The aggregation of Fe2(MoO4)3 is severe with the increasing calcination temperature. Fe2(MoO4)3 is stable below 600 °C, while MoO3 phase could be subliming with the increasing temperature. The catalytic performance of iron-molybdenum catalyst has closely correlation with the phase compositions, which can be controlled by synthesis temperature and Mo/Fe molar ratio. The iron-molybdenum catalyst with Mo/Fe atomic ratio of 2.6 calcined at 500 °C for 4 h showed the best methanol conversion (100%) and formaldehyde yield (92.27%).

With the rapid developments of artificial intelligence (AI) and deep learning (DL) techniques, it is critical to ensure the security and robustness of the deployed algorithms. Recently, the security vulnerability of DL algorithms to adversarial samples has been widely recognized. The fabricated samples can lead to various misbehaviors of the DL models while being perceived as benign by humans. Successful implementations of adversarial attacks in real physical-world scenarios further demonstrate their practicality. Hence, adversarial attack and defense techniques have attracted increasing attention from both machine learning and security communities and have become a hot research topic in recent years. In this paper, we first introduce the theoretical foundations, algorithms, and applications of adversarial attack techniques. We then describe a few research efforts on the defense techniques, which cover the broad frontier in the field. Several open problems and challenges are subsequently discussed, which we hope will provoke further research efforts in this critical area. Keywords: Machine learning, Deep neural network, Adversarial example, Adversarial attack, Adversarial defense

To study the heights of the caved zone and water-conducting fracture zone in backfill mining, the failure mechanism of strata during backfill mining was analyzed, and a method for determining the heights of the two zones was proposed based on key strata theory. The movement and failure regularity of the strata above the backfilling panel were revealed through numerical simulation. Considering the geologic conditions of the CT101 backfilling panel, the height of the fracture zone was determined using the proposed method along with empirical calculation, numerical simulation, and borehole detection. The results of the new calculation method were similar to in situ measurements. The traditional empirical formula, which is based on the equivalent mining height model, resulted in large errors during calculation. The findings indicate the reliability of the new method and demonstrate its significance for creating reference data for related studies.

Garlic (Allium sativum L.) is an important bulb vegetable with high culinary and medicinal values. It is cultivated by exclusively vegetative propagation which leads to complex virus infection, biodiversity reduction, inhibition of multiple breeding strategies. An efficient and widely applicable shoot regeneration system was established from garlic inflorescence as explant. By optimizing the basal medium type, pH value and explant size, a mean shoot regeneration rate of 97% and mean shoot number of 23.4 per explant were achieved in 14 commercial cultivars with various characteristics and origins. Histological observation revealed that shoots were regenerated through direct organogenesis when meristemoid initiated from subepidermal cells without callus formation followed by periclinal and anticlinal division of epidermal and subepidermal cells. No polymorphic bands were detected by simple sequence repeat (SSR) analysis between regenerants and donor plants. Furthermore, flow cytometry analysis indicated that there was no significant variability of genome size, and all plants maintained their ploidy. These results confirmed the clonal fidelity of regenerants. In conclusion, the present study provides a shoot regeneration system with great potential in micropropagation, germplasm preservation, genetic transformation and ploidy manipulation of garlic. Our study developed a widely applicable procedure for direct shoot regeneration via inflorescence of garlic and ascertained the clonal fidelity of regenerants by using simple sequence repeat (SSR) and flow cytometry.

Color is the most intuitive feature of different tea infusions. The accurate measurement of pigments is one of the important means for tea quality and bioactive appraisal. In this study, a stable, ...

Food is essential for human life and has been the concern of many healthcare conventions. Nowadays new dietary assessment and nutrition analysis tools enable more opportunities to help people understand their daily eating habits, exploring nutrition patterns and maintain a healthy diet. In this paper, we develop a deep model based food recognition and dietary assessment system to study and analyze food items from daily meal images (e.g., captured by smartphone). Specifically, we propose a three-step algorithm to recognize multi-item (food) images by detecting candidate regions and using deep convolutional neural network (CNN) for object classification. The system first generates multiple region of proposals on input images by applying the Region Proposal Network (RPN) derived from Faster R-CNN model. It then indentifies each region of proposals by mapping them into feature maps, and classifies them into different food categories, as well as locating them in the original images. Finally, the system will analyze the nutritional ingredients based on the recognition results and generate a dietary assessment report by calculating the amount of calories, fat, carbohydrate and protein. In the evaluation, we conduct extensive experiments using two popular food image datasets - UEC-FOOD100 and UEC-FOOD256. We also generate a new type of dataset about food items based on FOOD101 with bounding. The model is evaluated through different evaluation metrics. The experimental results show that our system is able to recognize the food items accurately and generate the dietary assessment report efficiently, which will benefit the users with a clear insight of healthy dietary and guide their daily recipe to improve body health and wellness.

CoS2 nanooctahedrons homogeneously encapsulated by hierarchical porous-reduced graphene oxide and polypyrrole thin film are constructed via a simple hydrothermal route, followed by vapor polymerization reaction. Owing to the porous conductive network and robust structural integrity characteristics, the optimal CoS2@RGO@PPy aerogel can not only facilitate electron and ion transfer but also shorten diffusion length and alleviate strain stress, ensuring superior sodium storage in terms of high capacity, excellent rate capability, and cycling stability. With a CoS2 content of 54.9%, CoS2@RGO@PPy electrode delivers a discharge capacity of 744 mAh g−1 at the current density of 0.1 A g−1. Moreover, it yields a reversible capacity of 554 mAh g−1 at 2.0 A g−1, higher than that of 495 mAh g−1 for CoS2@RGO electrode. The superior rate capability can be attributed to the favored surface capacitive behavior. And a combined contribution of diffusion-controlled and capacitive-induced process are derived. Furthermore, CoS2@RGO@PPy electrode maintains 348 mAh g−1 over a long period of 700 cycles at a high current density of 3 A g−1 and a capacity retention of 65.8%. The strategy can be extended to tailor the electrode structures for high-performance sodium-ion batteries.

Background Population-based studies on the associations of long-term exposure to particulate matter (PM) with androgen and progesterone are still scant. Residential greenness is benefits health by promoting physical activity, reducing air pollution, and improving mental health, but it remains unclear whether it is related to androgen and progesterone levels among humans. Aims This study aimed to explore the individual and interactive effects of PM and residential greenness on serum testosterone and progesterone levels among rural Chinese adults. Methods A total of 6017 subjects were recruited from the baseline of the Henan Rural Cohort Study in 2016. Serum testosterone and progesterone were measured with liquid chromatography-tandem mass spectrometry. Particulate matters (PM) (PM1, PM2.5, and PM10) were assessed by machine learning algorithms. Residential greenness was assessed using the normalized difference vegetation index (NDVI) within 500-m, 1000-m, and 3000-m buffers around participants’ residences. The effects of air pollutants and residential greenness and their interaction on serum testosterone and progesterone levels were assessed using linear mixed-effects models with township as a random intercept. Results After adjusting for potential confounding factors, a 1 μg/m3 increase in PM2.5 or PM10 was associated with a 0.037 or 0.030 ng/ml increase in serum testosterone, respectively, in females and with a 0.111 or 0.182 ng/ml decrease in serum progesterone, respectively, in males. A 1 μg/m3 increase in PM1, PM2.5 or PM10 was associated with a 0.222, 0.306, or 0.295 ng/ml decrease in serum progesterone, respectively, among females. Moreover, a 0.1-unit increase in NDVI was associated with a 0.310 ng/ml increase in serum testosterone and a 0.170 ng/ml increased in serum progesterone in males, as well as with a 0.143 ng/ml increase in serum progesterone in females. Interaction effects of PM and residential greenness on serum testosterone and progesterone levels were observed, indicating that the effects of residential greenness on serum testosterone and progesterone were modified by high levels of PM. In addition, physical activity significantly mediated 2.92% of the estimated association between greenness and testosterone levels. Conclusions Our study suggested that long-term exposure to PM was positively associated with serum testosterone in males but negatively associated with progesterone levels in both genderssin. In addition, positive associations of residential greenness with serum testosterone and progesterone levels were observed, but they were modified by high levels of PM. Furthermore, the estimated effects of residential greenness on testosterone levels were partly mediated by physical activity.

High-valence cobalt sites are considered as highly active centers for the oxygen evolution reaction (OER) and their corresponding construction is thus of primary importance in the pursuit of outstanding performance. Herein, we report the design and facile synthesis of abundant high-valence cobalt sites by introducing Zn2+ into CoFe Prussian blue analogues (PBAs). The modification results in the drastic morphological transformation from a pure phase (CoFe-PBA) to a three-phase composite (CoFeZn-PBA), with a significant increase not only the amount of highly oxidized Co sites but the specific surface area (by up to 4 times). Moreover, the obtained sample also exhibits outstanding electric conductivity. Consequently, an excellent OER performance with an overpotential of 343 mV@10 mA cm-2 and a Tafel slope of 75 mV dec-1 was achieved in CoFeZn-PBA, which outperforms the commercial IrO2 catalyst. Further analysis reveals that CoFeZn-PBA becomes (oxyhydr)oxides after the OER.

The eastern North Pacific (ENP) has the highest density of tropical cyclones (TCs) on earth, and yet the controls on TCs, from individual events to seasonal totals, remain poorly understood. One effect that has not been fully considered is the unique geography of the Central American mountains. Although observational studies suggest these mountains can readily fuel individual TCs through dynamical processes, here we show that these mountains indeed play the opposite role on the seasonal timescale, hindering seasonal ENP TC activity by up to 35%. We found that these mountains significantly interrupt the abundant moisture transport from the Caribbean Sea to the ENP, limiting deep convection over the open ocean area where TCs preferentially occur. This study advances our fundamental understanding of ENP TC genesis mechanisms across the weather-to-climate timescales, and also highlights the importance of topography representation in improving the ENP regional climate simulations, as well as TC seasonal predictions and future projections., How the Central American mountains influence tropical cyclone (TC) development in the eastern North Pacific is not well understood. Here, the authors use model simulations to show that on a seasonal timescale, these mountains interrupt moisture transport from the Caribbean Sea and as a result, reduce TC activity by up to 35%.

To reveal the mechanism of temperature preference in Tuta absoluta, one of the top 20 plant pests in the world, we cloned and identified TaTRPA1, TaPain, and TaPyx genes by RACE and bioinformatic analysis, and clarified their expression profiles during different development stages using real-time PCR, and revealed their function in preference temperature by RNAi. The full-length cDNA of TaPain was 3136 bp, with a 2865-bp open reading frame encoding a 259.89-kDa protein, and the partial length cDNA of TaPyx was 2326-bp, with a 2025-bp open reading frame encoding a 193.16-kDa protein. In addition, the expression of TaTRPA1 and TaPyx was significantly lower in larvae than other stages, and it was significantly higher in pupae and newly emerging males for TaPain. After feeding target double-stranded RNA (dsRNA), the preferred temperature decreased 2 °C more than the control group. In conclusion, the results firstly indicated the molecular characterization of TRPA subfamily genes and their key role in temperature perception in T. absoluta, and the study will help us to understand the temperature-sensing mechanism in the pest, and will provide some basis for study of other Lepidoptera insects’ temperature preference. Moreover, it is of great significance in enriching the research progress of “thermos TRP”.

The trifluoromethylation of benzoic acids with TMSCF3 was achieved through nucleophilic substitution with the use of anhydrides as an in situ activating reagent. Under the reaction conditions, a wide range of carboxylic acids including the bioactive ones worked well, thus providing a facile and efficient method for preparing aryl trifluoromethyl ketones from the readily available starting materials.

Different from traditional expanded graphite, novel slight-expanded graphite with only four times expansion was produced. The preparation method presented here includes an improved Hummers method t...

A novel crystalline high-silica zeolite with 12×8-membered ring (R) channel system is prepared with the aid of the 3D electron diffraction (3D ED) technique. A crystal with the same topology as one of the predicted daughter structures of CIT-13 germanosilicate, named ECNU-23 (East China Normal University 23) was coincidentally detected by the 3D ED investigation during the structure characterization of the "pure" powder sample of existing one-dimension (1D) 10-R ECNU-21. By controlling the alkaline-assisted hydrolysis under moderate conditions, we purified the phase of ECNU-23 by selectively breaking and removing the chemically weak Ge(Si)-O-Ge and metastable Si-O-Si bonds. Its structure was determined based on the 3D ED data, and confirmed by high-resolution TEM images and powder X-ray diffraction (PXRD) data. The aluminosilicate Al-ECNU-23 shows unique catalytic properties in the isomerization/ disproportionation of m-xylene as solid-acid catalyst.

A two-year field and micro-plot 15N-labelled experiment was conducted under two levels of N application rate (240 and 180 kg N ha–1) with three basal N application stages [seeding (L0), fou...