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Graphene is a two-dimensional material that can be folded into diverse and yet interesting nanostructures like macro-scale paper origami. Folding of graphene not only makes different morphological configurations but also modifies their mechanical and thermal properties. Inspired by paper origami, herein we studied systemically the effects of creases, where sp2 to sp3 bond transformation occurs, on the thermal properties of graphene origami using molecular dynamics (MD) simulations. Our MD simulation results show that tensile strain reduces (not increases) the interfacial thermal resistance owing to the presence of the crease. This unusual phenomenon is explained by the micro-heat flux migration and stress distribution. Our findings on the graphene origami enable the design of the next-generation thermal management devices and flexible electronics with tuneable properties.

In this manuscript, a purely data-driven statistical regularization method is proposed for extracting the information from big data with randomly distributed noise. Since the variance of the noise may be large, the method can be regarded as a general data preprocessing method in ill-posed problems, which is able to overcome the difficulty that the traditional regularization method is unable to solve, and has superior advantage in computing efficiency. The unique solvability of the method is proved, and a number of conditions are given to characterize the solution. The regularization parameter strategy is discussed, and the rigorous upper bound estimation of the confidence interval of the error in the L 2 L^{2} norm is established. Some numerical examples are provided to illustrate the appropriateness and effectiveness of the method.

Parameter estimation in chaotic dynamical systems is an important and practical issue. Nevertheless, the high-dimensionality and the sensitive dependence on initial conditions typically makes the problem difficult to solve. In this paper, we propose an innovative parameter estimation approach, utilizing numerical differentiation for observation data preprocessing. Given plenty of noisy observations on a portion of dependent variables, numerical differentiation allows them and their derivatives to be accurately approximated. Substituting those approximations into the original system can effectively simplify the parameter estimation problem. As an example, we consider parameter estimation in the well-known Lorenz model given partial noisy observations. According to the Lorenz equations, the estimated parameters can be simply given by least squares regression using the approximated functions provided by data preprocessing. Numerical examples show the effectiveness and accuracy of our method. We also prove the uniqueness and stability of the solution.

Effectively absorbing and converting electromagnetic (EM) energy for reutilization has an important implication in the fields of energy and environment. Herein, multi-walled carbon nanotubes (MWCNTs) are confinedly implanted into flower-like cobaltosic oxide (Co3O4) to tailor the conductive network and polarization genes. It controllably tunes the EM property and optimizes the low-frequency microwave absorption. The minimum reflection loss reaches −61.4 dB at 3.44 GHz. A novel self-powered device is constructed to achieve the effective conversion from waste EM energy to useful electric energy. Energy conversion process inside flower-like Co3O4-MWCNT architecture is investigated, and the contribution of dielectric loss and magnetic loss to energy conversion is exhibited. This work provides a promising approach in combating EM pollution and alleviating energy problem.

Flame stabilization is the key to extending scramjets to hypersonic speeds; accordingly, this topic has attracted much attention in theoretical research and engineering design. This study performed large eddy simulations (LESs) of lifted hydrogen jet combustion in a stepped-wall combustor, focusing on the flame stabilization mechanisms, especially for the autoignition effect. An assumed probability density function (PDF) approach was used to close the subgrid chemical reaction source. The reliability of the solver was confirmed by comparing the LES results with experimental data and published simulated results. The hydrogen jet and the incoming stream were first mixed by entraining large-scale vortices in the shear layer, and stable combustion in the near-wall region was achieved downstream of the flame induction region. The autoignition cascade is a transition of fuel-rich flame to stoichiometric ratio flame that plays a role in forming the flame base, which subsequently causes downstream flame stabilization. Three cases with different jet total temperatures are compared, and the results show that the increase in the total temperature reduces the lift-off distance of the flame. In the highest total temperature case, an excessively large scalar dissipation rate inhibits the autoignition cascade, resulting in a fuel-rich low-temperature flame.

We generalize the P(N)-graded Lie superalgebras of Martinez-Zelmanov. This generalization is not so restrictive but sufficient enough so that we are able to have a classification for this generalized P(N)-graded Lie superalgebras. Our result is that the generalized P(N)-graded Lie superalgebra L is centrally isogenous to a matrix Lie superalgebra coordinated by an associative superalgebra with a super-involution. Moreover, L is P(N)-graded if and only if the coordinate algebra R is commutative and the super-involution is trivial. This recovers Martinez-Zelmanov’s theorem for type P(N). We also obtain a generalization of Kac’s coordinatization via Tits-Kantor-Koecher construction. Actually, the motivation of this generalization comes from the Fermionic-Bosonic module construction.

Iron can not be recovered at high value because only rare earth elements are effectively recovered from NdFeB waste via oxidation roasting-hydrochloric acid leaching process. In this study, a new method for leaching NdFeB waste with oxalic acid was developed. The high-efficiency, simultaneous and high-value recovery of rare earth elements and iron was realized to simplify the process and improve the economic benefit. Results of the oxalic acid leaching experiments show that under the optimum leaching conditions at 90 °C for 6 h in the aqueous solution of oxalic acid (2 mol/L) with a liquid–solid ratio of 60 mL/g, the iron leaching efficiency and precipitation rate of rare earth oxalate reach 93.89% and 93.17%, respectively. Rare earth oxalate and Fe(C2O4)33− were left in the residue and the leaching solution, respectively. The leaching mechanism was further analyzed by characterising the leach residues obtained through X-ray powder diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). Results of the leaching kinetics study indicate that the process of oxalic acid leaching follows the shrinking nucleus model, and the leaching kinetics model is controlled by the mixed factors of diffusion and chemical reaction. The leaching residue was calcined at 850 °C for 3 h and then decomposed into rare earth oxide, which can be directly used to prepare rare earth alloy via molten salt electrolysis. For the leaching solution, ferric oxalate solution was reduced using Fe powder to prepare the ferrous oxalate (FeC2O4·2H2O).

In this study, a method based on fuzzy gray level aura matrix (FGLAM) textural feature and spectral feature fusion is proposed to improve the accuracy of wood species classification. The experimental dataset is acquired by two sensors. The visible images of wood samples are acquired using a RGB image acquisition platform, and the spectral curves are acquired using a USB2000-VIS-NIR spectrometer having a spectral band of 350–1100 nm. Firstly, the textural features are computed by using FGLAM for gray level wood sample images. The original spectral curve is smoothed and corrected to remove noise. Secondly, the obtained textural features and spectral features are processed in extreme learning machine to complete the decision-level fusion and obtain the classification results. The experimental results for 15 wood species show that the classification accuracy of the textural feature by using FGLAM alone can reach to 90%, which is better than that acquired using the traditional gray level co-occurrence matrix, local binary pattern, and the mainstream improved basic gray level aura matrix. Moreover, the classification accuracy based on the FGLAM textural feature and spectral feature fusion proposed in this paper can reach to 100%. Finally, for 8 similar wood species, the recognition accuracy of the present fusion scheme reaches to 98.75%, which is also better than those state-of-the-art methods.

Strain engineering is a highly effective tool for tuning the lattice parameter and in turn optimizing the optical, electronic, and chemical properties of numerous functional materials. In conventio...

Perovskite Ba0.67Sr0.33TiO3 (BST) ceramics with improved dielectric performance were fabricated by a novel direct coagulation casting via high valence counter ions (DCC-HVCI) method using 0.5 mol% MgO as the coagulation agent. The influence of sintering temperature on micromorphology, crystal structure, and dielectric performance of BST ceramic components was systematically evaluated. The densification rate of BST samples could reach the maximum at a heating temperature around 1305 °C and end up approximately at 1380 °C. As increasing the sintering temperature from 1400 to 1550 °C, the relative density of BST ceramics decreases from 98.82 ± 0.16% to 96.72 ± 0.06%, and the mean grain size drops gradually from 9.96 to 4.68 μm. The increased sintering temperature promotes the lattice expansion due to Ti4+ replacement at B site by Mg2+, as well as the generation of oxygen vacancies. In addition, as increasing sintering temperature, the dielectric permittivity (er) of BST ceramic components decreases first and then slightly increases, while the dielectric loss (tanδ) of ceramics shows the opposite trend. The results indicate that the initial tanδ increase is mainly attributed to the lattice expansion of BST ceramics, and the subsequent loss reduction results from the easily localized conduction electrons on Mg2+ sites reducing the carrier concentration. The samples sintered at 1550 °C show the lowest dielectric loss (tanδ≈0.013), which is significantly reduced by an order of magnitude compared with that of dry-pressed samples (tanδ≈0.262).

Conversion of the numerous aryl ketones into aryl electrophiles via Ar–C(O) cleavage remains a challenging yet highly desirable transformation in Sonogashira-type coupling. Herein, we report a pall...

A new stochastic isogeometric analysis method based on reduced basis vectors (SRBIGA) is proposed for engineering structures with random field material properties and external loads. Based on the Galerkin isogeometric functions, the proposed SRBIGA applies the Karhunen–Loeve expansion to discretize the random field uncertainties. Inspired by the stochastic Krylov subspace theory, the structural responses of linear elasticity structures with random field uncertainties are represented based on the reduced basis vectors. The tremendous advantage of SRBIGA over the spectral stochastic isogeometric analysis (SSIGA) in terms of the computational efficiency is disclosed through the comparison analysis in theoretical aspects. Three illustrative examples demonstrate that the proposed SRBIGA has not only significantly higher efficiency but also higher accuracy and better robustness than the SSIGA and that it can provide a novel and expedient stochastic structural analysis method for practical large-scale complex engineering structures when both material properties and external loads are spatially random.

A multi-functional electromagnetic (EM) device is an important pillar for promoting the progress of an intelligent society. Herein, a ZIF-67 nanoneedle array assembled on a nickel substrate is used as a precursor to construct a C/Co3O4 nanoarray via a simple thermal treatment approach, integrating the two functions of EM and thermal shielding. Its unique three-dimensional porous structure and integrated components endow this material with an average shielding efficiency of 99.62% and a maximum temperature difference of about 25 K. In addition, this skeleton structure features light weight, low density and small cost, which can be utilized to construct wearable devices to protect human beings from EM and thermal radiation. This study furnishes a novel horizon for the design and construction of multi-functional and wearable EM devices, and promotes the development of the EM field and the progress of multi-disciplinary technologies.

The advent of 5G and 6G eras switches on intelligent life and information revolution. Unfortunately, the resulting electromagnetic radiation would harm human health and current automation systems. Hence, the worldwide demand for novel and efficient electromagnetic functional materials has been growing dramatically. Metal–organic frameworks (MOFs), which possess diverse structures and components, have inspired infinite passion and creativity of researchers in the electromagnetic field. Herein, the recent progress in synthesis of MOF architectures is discussed. Then, the attenuation mechanism of electromagnetic waves inside MOF architectures is revealed, and the development of highly efficient MOF-based microwave absorption and shielding materials with tunable electromagnetic properties is presented. Finally, the current challenges and possible future research directions are dissected, which provides guidance for fabricating MOF-based electromagnetic functional materials.

Chiral assemblies by combining natural biomolecules with plasmonic nanostructures hold great promise for plasmonic enhanced sensing, imaging, and catalytic applications. Herein, we demonstrate that human serum albumin (HSA) and porcine serum albumin (PSA) can guide the chiral assembly of gold nanorods (GNRs) with left-handed chiroptical responses opposite to those by a series of other homologous animal serum albumins (SAs) due to the difference of their surface charge distributions. Under physiological pH conditions, the assembly of HSA or PSA with GNRs yielded left-handed twisted aggregates, while bovine serum albumin (BSA), sheep serum albumin, and equine serum albumin behaved on the contrary. The driving force for the chiral assembly is mainly attributed to electrostatic interaction. The opposite chiroptical signals acquired are correlated with the chiral surface charge distributions of the tertiary structures of SAs. Moreover, the chirality of the assembly induced by both HSA and BSA can be enhanced or reversed by adjusting the pH values. This work provides new insights into the modulation of protein-induced chiral assemblies and promotes their applications.

Arbuscular mycorrhizal fungi (AMF) can benefit many plants, but their effects on walnuts are not yet known. The present study aimed to analyze the effect of five AMF species, namely, Acaulospora scrobiculata, Diversispora spurca, Glomus etunicatum, G. mosseae and G. versiforme on biomass production, chlorophyll contents, sugar fraction contents, and mineral element contents of walnut (Juglans regia L.) seedlings. The five AMF species colonized roots of walnut, established mycorrhizas in roots and hyphae in soil, and released easily extractable glomalin-related soil protein into soil, whilst D. spurca exhibited the best effect. All the AMF inoculations, except A. scrobiculata, stimulated shoot and root biomass production. Mycorrhizal fungal inoculations collectively increased leaf chlorophyll a, chlorophyll b, and total chlorophyll a+b concentrations, and thus promoted leaf sucrose accumulation, which provides an important mycorrhiza-carbon source to roots. AMF inoculations conferred a positive effect on leaf N, P, K, Mg, Fe, B, Zn and Cu contents, while they reduced leaf Mn contents. These results concluded that AMF were beneficial to the growth and physiological activities of walnut, which gives the support for the AMF application in walnut.

Variable-order space-fractional diffusion equations provide very competitive modeling capabilities of challenging phenomena, including anomalously superdiffusive transport of solutes in heterogeneous porous media, long-range spatial interactions and other applications, as well as eliminating the nonphysical boundary layers of the solutions to their constant-order analogues. In this paper, we prove the uniqueness of determining the variable fractional order of the homogeneous Dirichlet boundary-value problem of the one-sided linear variable-order space-fractional diffusion equation with some observed values of the unknown solutions near the boundary of the spatial domain. We base on the analysis to develop a spectral-Galerkin Levenberg–Marquardt method and a finite difference Levenberg–Marquardt method to numerically invert the variable order. We carry out numerical experiments to investigate the numerical performance of these methods.

The Boltzmann collision operator for long-range interactions is usually employed in its “weak form” in the literature. However the weak form utilizes the symmetry property of the spherical integral and thus should be understood more or less in the principle value sense especially for strong angular singularity. To study the integral in the Lebesgue sense, it is natural to define the collision operator via the cutoff approximation. In this way, we give a rigorous proof to the local well-posedness of the Boltzmann equation with the long-range interactions. The result has the following main features and innovations: (1). The initial data is not necessarily a small perturbation around equilibrium but satisfies compatible conditions. (2). A quasi-linear method instead of the standard linearization method is used to prove existence and non-negativity of the solution in a suitably designed energy space depending heavily on the initial data. In such space, we derive the first uniqueness result for the equation in particular for hard potential case.

DNA origami enables the manipulation of objects at nanoscale, and demonstrates unprecedented versatility for fabricating both static and dynamic nanostructures. In this work, we introduce a new strategy for transferring modular reconfigurable DNA nanostructures from two-dimensional to three-dimensional. A 2D DNA sheet could be modularized into connected parts (e.g., two, three, and four parts in this work), which can be independently transformed between two conformations with a few DNA "trigger" strands. More interestingly, the transformation of the connected 2D modules can lead to the controlled, resettable structural conversion of a 2D sheet to a 3D architecture, due to the constraints induced by the connections between the 2D modules. This new approach can provide an efficient mean for constructing programmable, higher-order, and complex DNA objects, as well as sophisticated dynamic substrates for various applications.

A mixed-spin (5/2, 3/2) Ising model is established to describe the antiferroelectric/ferroelectric (AFE/FE) BiFeO3/Co bilayer structure. We study the effects of the crystal field, exchange coupling and external longitudinal electric field on the dielectric properties of the bilayer based on Monte Carlo simulation. We illustrate the temperature dependence of polarization, susceptibility, internal energy and specific heat of the system in detail. As well, we depict the phase diagram and point out the rule of the blocking temperature with various parameters. In particular, we find rich and interesting multi-cycle electric hysteresis behaviors. The results show that these parameters play a crucial part in the physical properties of the AFE/FE BiFeO3/Co bilayer structure.

Nowadays, the sound source localization is widely applied in various fields, with a focus on arrays or algorithms. Meanwhile, acoustic metasurfaces have recently attracted enormous interest in material science. This paper proposed a kind of piezoelectric acoustic metasurface, whose structure is theoretically proved to be useful in sound field orientation or sound source localization. The metasurfaces consist of forty units made up of a resonance-like cavity and a piezoelectric composite sheet in air. By scanning through space and frequency, it has been investigated that the effective interval can reach $$30^\circ \le \theta \le 150^\circ $$ and $$-200\le x\le 200\,\hbox {cm}$$ under far-field and near-field scenario, respectively. Meanwhile, the bandwidth of the structure was evaluated to be up to 800–900 Hz in both scenarios. In addition, this paper analyzed three factors affecting the interval: frequency, the size of the metasurface, and the number of elements. The results of this paper has opened up a new way for sound source localization and metasurfaces.

In order to solve the problem of lack of unified evaluation criteria for water quality evaluation in the Three Gorges Reservoir under different hydrologic condition, hydraulic retention time and flow rate were calculated wih the hydrological data of 6 intact hydrological years after the 175 m impoundment in the Three Gorges Reservoir using the concept of segment capacity. Results indicate that the hydrological conditions of the Three Gorges Reservoir have obvious spatial and temporal differences. The whole river should be evaluated according to the river standard during the wet season. In the dry season, the upstream of Wanxian should be evaluated according to the river standards and the downstream of Wanxian should be evaluated according to lake standard. The tributary bay should be evaluated according to the lake standard. The conclusion obtained by this evaluation method is consistent with actual situation of the reservoir, providing a theoretical basis and technical support for the targeted protection of water environment in river-type reservoirs.

Graphene origami (G-ori) can possess unique mechanical properties and achieve some distinctive functionalization by engineering their configurations. However, it remains a tremendous challenge to modulate its formation and properties at the micro- and nano-scales. Herein, we systemically present the formation of G-ori activated by creased marks via molecular dynamics (MD) simulations. The pre-existing creased mark in graphene is created in a controlled way by transforming sp2 to sp3 bonds at the crease. Our results show that the presence of interlayer sp3 bonds at the crease can direct crack growth and hence pave a new way to tailor graphene sheets into specified pieces. The crease also guides the folding process of graphene into various geometric configurations. Sophisticated G-ori can be constructed by designing rational crease distribution on the graphene surface. Checking against the folding process of paper origami shows that the crease-induced targeted folding can be achieved at both nano- and macro-scales in exactly the same way. Our findings provide a simple and feasible method to construct graphene-based nano-devices by designing rational morphological configurations of G-ori.

The direct, nonoxidative conversion of methane on a silica-confined single-atom iron catalyst is a landmark discovery in catalysis, but the proposed gas-phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe1 ©SiC2 ), followed by C-C coupling and hydrogen transfer to produce the main product (ethylene) via a key -CH-CH2 intermediate. We find a quasi Mars-van Krevelen (quasi-MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe1 ©SiO2 and this surface process is identified to be more plausible than the alternative gas-phase reaction mechanism.

3-Ketosteroid Δ1-dehydrogenase (KsdD) is the key enzyme responsible for Δ1-dehydrogenation, which is one of the most valuable reactions for steroid catabolism. Arthrobacter simplex has been widely used in the industry due to its superior bioconversion efficiency, but KsdD information is not yet fully clear. Here, five KsdD homologues were identified in A. simplex CGMCC 14539. Bioinformatic analysis indicated their distinct properties and structures. Each KsdD was functionally confirmed by transcriptional response, overexpression, and heterologous expression. The substantial difference in substrate profiles might be related to the enzyme loop structure. Two promising enzymes (KsdD3 and KsdD5) were purified and characterized, exhibiting strong organic solvent tolerance and clear preference for 4-ene-3-oxosteroids. KsdD5 seemed to be more versatile due to good activity on substrates with or without a substituent at C11 and high optimal temperature and also possessed unique residues. It is the first time that KsdDs have been comprehensively disclosed in the A. simplex industrial strain.

Ba0.67Sr0.33TiO3 (BST) ceramics with highly improved dielectric performance were fabricated by a novel direct coagulation casting via high valence counter ions (DCC-HVCI) method. The influence of solid loading on densification behavior, micromorphology, and dielectric performance of the samples was investigated. With the increase of solid loading from 40 to 50 vol%, the maximum densification rate of BST ceramics increased from 0.090 to 0.122 s−1, and the densification temperature decreased from 1424 to 1343 °C, which indicated that high solid loading could promote the densification behavior of samples during sintering. BST ceramics fabricated by the DCC-HVCI method showed uniform grain size and microstructure, which was beneficial for the dielectric properties of BST ceramics. Samples obtained from 45 vol% suspensions possessed the lowest dielectric permittivity (er ≈ 2801), and the dielectric loss (tanδ≈0.0262) was about 1/10 of that of dry-pressed samples (tanδ≈0.301), which could be attributed to the composition homogenization.

Molecular patterns with nanoscale precision have been used to mimic complex molecular networks. One key challenge in molecular patterns is to perform active pattern operations in controllable systems to fully imitate their complex dynamic behaviors. Here, we present a reconfigurable DNA origami domino array-based dynamic pattern operation (DODA DPO) system to perform proximity-induced molecular control for complex pattern operations. The activatable platform of reconfigurable DODA endows a spontaneous cascade of stacking conformational transformation from the "before" to the "after" conformation by a set of "trigger" DNA strands. The conformational transformation further brings the operational pattern units into close proximity to undergo DNA strand displacement cascades to accomplish three different pattern operations of "writing", "erasing", and "shifting". Our results also demonstrate the reconfigurable DODA DPO system provides a useful basis to study various molecular control analysis in a fully programmable and controllable fashion.

We report a success in synthesizing high entropy silicides (HES) compounds and manufacturing well-densified HES ceramics through spark plasma sintering. For a designed chemical formula as (Ti0.2Zr0.2Nb0.2Mo0.2W0.2)Si2, the as-synthesized HES showed a formula as (Ti0.22Zr0.06Nb0.29Mo0.22W0.21)Si2 with zirconium partially oxidized into zirconia. Doping with aluminum resulted in a HES with the same composition, promoted formation of ZrSi2 and Al2O3. XRD analysis of as-synthesized HES is well supported by the calculated diffraction data based on a 2 × 3 × 1 supercell with HCP crystal structure and experimental chemical composition. The cations in this HES crystal structure can occupy their positions randomly with little change of its lattice parameters and formation enthalpy.

A copper-catalyzed oxalamide-directed ortho-C-H amination of anilines has been developed by using 1 atm of air as the sole oxidant. The protocol shows excellent functional group tolerance, and some heterocyclic amines including indole, benzothiophene, benzothiazole, quinoline, isoquinoline, and quinoxaline could be compatible in the reaction. The late-stage diversification of medicinal drugs demonstrates the synthetic utility of this protocol.

Synthesis of well-defined atomically mixed alloy nanoparticles on desired substrates is an ultimate goal for their practical application. Herein we report a general approach for preparing atomically mixed AuPt, AuPd, PtPd, AuPtPd NAs(nanoalloys) through single-atom level manipulation. By utilizing the ubiquitous tendency of aggregation of single atoms into nanoparticles at elevated temperatures, we have synthesized nanoalloys on a solid solvent with CeO2 as a carrier and transition-metal single atoms as an intermediate state. The supported nanoalloys/CeO2 with ultra-low noble metal content (containing 0.2 wt % Au and 0.2 wt % Pt) exhibit enhanced catalytic performance towards complete CO oxidation at room temperature and remarkable thermostability. This work provides a general strategy for facile and rapid synthesis of well-defined atomically mixed nanoalloys that can be applied for a range of emerging techniques.

Ploidy diversity provides valuable scientific information, thus making the detection technique of ploidy important. However, traditional methods of cytological observation and flow cytometry are either laborious or expensive. We here report a simple and rapid, effective and economical quantitative PCR (qPCR) approach to determine the ploidy of a parasitoid species Trichogramma dendrolimi Matsumura, an economically important biocontrol agent. We applied a mitochondrial gene cytochrome oxidase (COI) and a nuclear gene forkhead to evaluate the mitochondrial number per nuclear copy in a thelytokous Wolbachia-infected strain of T. dendrolimi and its bisexual uninfected counterparts. The 2−ΔCq values calculated from Cq values which resulted from qPCR experiments were significantly larger in haploid males than that in diploid females. Haploid males possessed about 2.69 times mitochondrial number per nuclear copy as diploid females. Not a single significant difference was found between diploid females from thelytokous and bisexual strains. Based on the differences in relative mitochondrial content, we were allowed to distinguish between haploid males and diploid females. Moreover, the number of mitochondria significantly decreased with higher ploidy level but was not affected by Wolbachia-infection. Our study supplied an available tool to investigate the ploidy diversity in sex determination of T. dendrolimi and thelytokous manipulation of Wolbachia, which is the crucial step to further study their underlying mechanisms. This will in turn contribute to the biocontrol efficiency by enhancing the female production and hence the parasitism rate.

Metal-organic framework (MOF) materials have highly sought after in electromagnetic materials and functional devices, due to the unique three-dimensional structure and electronic state. Herein, the tailoring strategy of MOF materials, including MOF precursors and carbonized derivatives, is combed for high-efficiency microwave absorbers. The design idea from microstructure to electromagnetic response is constructed. Based on these theories, the current research progress about MOF-based absorbers is presented, and the effect of microstructure tailoring to electromagnetic property and microwave absorption is revealed. In addition, the application of MOF materials in functional device is outlined. Finally, the current challenges for MOF materials and devices are overviewed, and the future development is expected.

Personalized zirconium dioxide (ZrO2) all-ceramic teeth are expected to be widely used in the field of oral restoration. Here, ZrO2 all-ceramic teeth were fabricated for biological engineering by photosensitive resin based digital light processing (DLP) technology. When sintered at 1500 °C for 3 h, dense ZrO2 ceramics were obtained with relative density of 98.02 ± 0.32%, Vickers hardness of 12.62 ± 0.15 GPa and fracture toughness of 6.11 ± 0.36 MPa∙m1/2, which were close to those of the ZrO2 ceramics prepared by dry pressing. To confirm whether the prepared ZrO2 ceramics possessed good biosafety, in vitro biological experiments were further performed with rat bone marrow mesenchymal stem cells (rBMSCs) and preferable cell attachment was observed at the initial stages. Results illustrated that the compositions with cytotoxicity in green samples were completely decomposed after debinding and sintering process, and the ZrO2 ceramics could provide an ideal biocompatible environment for mesenchymal stem cells. This study shows that ZrO2 all-ceramic teeth with personalized structure prepared by DLP technology have good mechanical properties and biocompatibility, exhibiting strong potential in the field of oral restoration.

Object shape reconstruction from images has been an active topic in computer vision. Shape-from-shading (SFS) is an important approach for inferring 3D surface from a single shading image. In this paper, we present a unified SFS approach for surfaces of various reflectance properties using fast eikonal solvers. The whole approach consists of three main components: a unified SFS model, a unified eikonal-type partial differential image irradiance (PDII) equation, and fast eikonal solvers for the PDII equation. The first component is designed to address different reflectance properties including diffuse, specular, and hybrid reflections in the imaging process of the camera. The second component is meant to derive the PDII equation under an orthographic camera projection and a single distant point light source whose direction is the same as the camera. Finally, the last component is targeted at solving the resultant PDII equation by using fast eikonal solvers. It comprises two Godunov-based schemes with fast sweeping method that can handle the eikonal-type PDII equation. Experiments on several synthetic and real images demonstrate that each type of the surfaces can be effectively reconstructed with more accurate results and less CPU running time.

Leaf growth and its interaction with the growing environment critically affect leaf area, distribution, and function, and ultimately affects grain yield of maize (Zea mays L.). To detect the effects of leaf area dynamics, growth periods, and the environment on maize grain yield, a three-year field experiment was conducted using two maize varieties, medium plant-size variety Zhengdan 958 (ZD958) and large plant-size variety Zhongnongda 4 (ZND4), and three to five sowing dates. The sowing date significantly affected maize yield as a result of changes in leaf area, growth stage, and growing environment. Prior to the 12th leaf stage, significant correlations between leaf area dynamics, environment, and yield were seldom detected. The expansion of leaf area from 12th leaf stage to silking stage was significantly positively correlated with growing degree days (GDD), solar radiation, and grain yield, indicating the importance of leaf area dynamics during this period. After silking, solar radiation played a more important role in inducing leaf senescence than GDD, particularly in the 2nd half of the grain filling stage. Accelerated leaf senescence in late growth period can increase maize yield. The environment affected leaf area dynamics and yield of the large plant-size variety (ZND4) more easily than the medium plant-size variety (ZD958) at the optimum plant density, reflecting the difference in varietal capacity to adapt to the growing environment. This study indicates that optimizing the interaction among leaf area dynamics, growth periods, and environment is a sound strategy to increase maize yield. Favorable interactions are useful to determine the optimal sowing date of a given variety.

Severe sintering conditions always cause defects that increase the dielectric loss of microwave ceramics. Direct coagulation casting (DCC) of submicron powder suspension, was applied to accelerate densification and enhance dielectric properties of 0.7CaTiO3-0.3NdAlO3 (CTNA) ceramics. The rapid in-situ coagulation of suspension was achieved by tailoring the pH value to the isoelectric point to weaken the repulsion of electric double layer and steric hindrance effect. Compared with the dry-pressed samples, the DCC-fabricated samples are more compacted, which provides a high initial densification value and a shortened diffusion path, and consequently promotes the material transportation and composition homogenization that inhibits the segregation of CaAl12O19. Additionally, the submicron powders accelerate the phase transition and domains growth, leading to a significant reduction of lattice defects in microstructure. Therefore, Q⋅f value of CTNA ceramics reaches more than 40,000 GHz, which is improved by 15 % compared with that of dry-pressed samples sintered under the same conditions.

In this paper, we propose a novel dynamical system with time delay to describe the outbreak of 2019-nCoV in China. One typical feature of this epidemic is that it can spread in latent period, which is therefore described by the time delay process in the differential equations. The accumulated numbers of classified populations are employed as variables, which is consistent with the official data and facilitates the parameter identification. The numerical methods for the prediction of outbreak of 2019-nCoV and parameter identification are provided, and the numerical results show that the novel dynamic system can well predict the outbreak trend so far. Based on the numerical simulations, we suggest that the transmission of individuals should be greatly controlled with high isolation rate by the government., Comment: 11 pages, 7 figures. arXiv admin note: text overlap with arXiv:2002.02590

BACKGROUND Trichogramma dendrolimi has been widely used in augmentative biocontrol of lepidopteran pests in China. In mass production of T. dendrolimi using Antheraea pernyi eggs as substitutive hosts, which are large in size, as clutch size is a parameter of importance to produce high quality parasitoids. Here, we aimed to determine the optimal clutch size for the bisexual Wolbachia-uninfected line (TdB) and Wolbachia-infected thelytokous line (TdT) of T. dendrolimi reared on A. pernyi eggs. RESULTS A medium clutch size of 42.75 to 62.27 for TdB and 52.93 to 57.14 for TdT was optimal to maximize fitness-correlated traits of parasitoid individual. The optimal clutch sizes with maximized parameters included adult emergence rate, adult body size, adult longevity, fecundity, and sum of fecundity of all females per brood were 58.31 (86.00%), 42.75 (231.11 μm), 50.92 (2.69 days), 62.27 (150.89 eggs), and 83.25 (7926.33 eggs) for TdB and 57.14 (94.54%), 52.93 (236.97 μm), 53.64 (2.62 days), 56.80 (161.01 eggs), and 70.10 (8579.71 eggs) for TdT. The TdT had a shorter adult longevity, longer development time, and higher adult emergence rate than did its non-infected bisexual counterpart. CONCLUSION A medium brood size in a A. pernyi egg host was optimal to produce offspring parasitoids with higher fitness parameters for both bisexual Wolbachia-uninfected and thelytokous Wolbachia-infected lines of T. dendrolimi. The determination of optimal clutch size for T. dendrolimi will provide the reference for the quality control of T. dendrolimi production and improvement of the field performance of the wasps. © 2020 Society of Chemical Industry.

How to model the 2019 CoronaVirus (2019-nCov) spread in China is one of the most urgent and interesting problems in applied mathematics. In this paper, we propose a novel time delay dynamic system with external source to describe the trend of local outbreak for the 2019-nCoV. The external source is introduced in the newly proposed dynamic system, which can be considered as the suspected people travel to different areas. The numerical simulations exhibit the dynamic system with the external source is more reliable than the one without it, and the rate of isolation is extremely important for controlling the increase of cumulative confirmed people of 2019-nCoV. Based on our numerical simulation results with the public data, we suggest that the local government should have some more strict measures to maintain the rate of isolation. Otherwise the local cumulative confirmed people of 2019-nCoV might be out of control., 13 pages, 13figures

Photocurable gray-colored Si3N4 ceramic slurry with high solid loading, suitable viscosity and high curing depth is critical to fabricate dense ceramic parts with complex shape and high surface precision by stereolithography technology. In the present study, Si3N4 ceramic slurry with suitable viscosity, high solid loading (45 vol %) and curing depth of 50 μm was prepared successfully when surface modifier KH560 (1 wt%) and dispersant Darvan (1 wt%) were used. The slurry exhibits the shear thinning behavior. Based on the Beer-Lambert formula, Dp (the attenuation length) and Ec (the critical energy dose) of Si3N4 ceramic slurry with solid loading of 45 vol % were derived as 0.032 mm and 0.177 mJ/mm2, respectively. Si3N4 ceramic green parts with complex shape and high surface precision were successfully fabricated by stereolithography technology. After optimizing the debinding and sintering process for green parts, dense Si3N4 ceramics with 3.28 g/cm3 sintering density were fabricated. The microhardness and fracture toughness of as-sintered Si3N4 ceramics are ~14.63 GPa and ~5.82 MPa m1/2, respectively, which are comparable to those of the samples by traditional dry-pressed and pressureless sintering technology. These results show that ceramic stereolithography technology could be promising to fabricate high performance ceramics, especially for gray-colored monolithic Si3N4 ceramics.

Atomically dispersed Fe–N–C materials recently hold great interest in costly Pt substitution for the cathodic oxygen reduction reaction of fuel cells. However, the heat treatment involved in the ma...

Single-atom catalysts (SACs) and single-cluster catalysts (SCCs) are the new frontier of heterogeneous catalysis, which exhibit high activity, selectivity, stability, and atomic efficiency as well as precise tunability. However, the lack of efficient methods for producing high-loading and high-purity SACs and SCCs hinders their industrial applications. In this work, we propose a general and efficient strategy for the production of high-loading and high-purity SACs and SCCs anchored on suitable substrates. Our strategy relies on the existence of an electrochemical potential window (EcPW) we predict within which any aggregate forms of the target metal on the substrate are leached away by electrochemical oxidation, while the strongly bound single atoms or single clusters remain at the substrate. We demonstrate the applicability of this strategy with modeling the production of Pt, Pd, and Ni SACs anchored on N-doped graphene and Fe2O3 as well as Pt3 and Ni3 SCCs anchored on graphdiyne.

Ethanol-tolerant Arthrobacter simplex is desirable since ethanol facilitates hydrophobic substrates dissolution on an industrial scale. Herein, alterations in compatible solutes were investigated under ethanol stress. The results showed that the amount of trehalose and glycerol increased while that of glutamate and proline decreased. The trehalose protectant role was verified and its concentration was positively related to the degree of cell tolerance. otsA, otsB and treS, three trehalose biosynthesis genes in A. simplex, also enhanced Escherichia coli stress tolerance, but the increased tolerance was dependent on the type and level of the stress. A. simplex strains accumulating trehalose showed a higher productivity in systems containing more ethanol and substrate because of better viability. The underlying mechanisms of trehalose were involved in better cell integrity, higher membrane stability, stronger reactive oxygen species scavenging capacity and higher energy level. Therefore, trehalose was a general protectant and the upregulation of its biosynthesis by genetic modification enhanced cell stress tolerance, consequently promoted productivity.

this article, we propose Sensitivity Minimization Learning (SML) to overcome the performance degradation problem caused by features corruption at the testing phase by using the stochastic sensitivity measure (STSM) as a regularizer. The STSM measures output deviations between each training sample and its noisy versions generated by a feature perturbation strategy. The feature perturbation strategy is user defined to simulate noises that our model target to defense at the testing phase. The SML is computational efficiency in training and testing phase and minimizes the generalization error on both training samples and its noise version set with feature perturbations. Models regularized by the STSM can be trained by the stochastic gradient descent algorithm efficiently and applied to very large scale applications. Experiment results on eight grayscale image, one color image, and two face databases show that the SML significantly outperforms several regularization techniques and yields much lower classification error when testing sets are contaminated with noises.

Chondral and osteochondral defects caused by trauma or pathological changes, commonly progress into total joint degradation, even resulting in disability. The cartilage restoration is a great challenge because of its avascularity and limited proliferative ability. Additionally, precise diagnosis using non-invasive detection techniques is challenging, which increases problems associated with chondral disease treatment. Methods: To achieve a theranostic goal, we used an integrated strategy that relies on exploiting a multifunctional nanoprobe based on chitosan-modified Fe3O4 nanoparticles, which spontaneously self-assemble with the oppositely charged small molecule growth factor, kartogenin (KGN). This nanoprobe was used to obtain distinctively brighter T2-weighted magnetic resonance (MR) imaging, allowing its use as a positive contrast agent, and could be applied to obtain accurate diagnosis and osteochondral regeneration therapy. Results: This nanoprobe was first investigated using adipose tissue-derived stem cells (ADSCs), and was found to be a novel positive contrast agent that also plays a significant role in stimulating ADSCs differentiation into chondrocytes. This self-assembled probe was not only biocompatible both in vitro and in vivo, contributing to cellular internalization, but was also used to successfully make distinction of normal/damaged tissue in T2-weighted MR imaging. This novel combination was systematically shown to be biosafe via the decrement of apparent MR signals and elimination of ferroferric oxide over a 12-week regeneration period. Conclusion: Here, we established a novel method for osteochondral disease diagnosis and reconstruction. Using the Fe3O4-CS/KGN nanoprobe, it is easy to distinguish the defect position, and it could act as a tool for dynamic observation as well as a stem cell-based therapy for directionally chondral differentiation.

In this paper, we establish a novel unique continuation property for two-dimensional anisotropic elasticity systems with partial information. More precisely, given a homogeneous elasticity system in a domain, we investigate the unique continuation by assuming only the vanishing of one component of the solution in a subdomain. Using the corresponding Riemann function, we prove that the solution vanishes in the whole domain provided that the other component vanishes at one point up to its second derivatives. Further, we construct several examples showing the possibility of further reducing the additional information of the other component. This result possesses remarkable significance in both theoretical and practical aspects because the required data is almost halved for the unique determination of the whole solution., 14 pages, 1 figure

The backward problems of parabolic equations are of interest in the study of both mathematics and engineering. In this paper, we consider a backward problem for the one-dimensional heat conduction equation with the measurements on a discrete set. The uniqueness for recovering the initial value is proved by the analytic continuation method. We discretize this inverse problem by a finite element method to deduce a severely ill-conditioned linear system of algebra equations. In order to overcome the ill-posedness, we apply the discrete Tikhonov regularization with the generalized cross validation rule to obtain a stable numerical approximation to the initial value. Numerical results for three examples are provided to show the effect of the measurement data.

Target detection circuits have been previously designed, which are propelled by conventional PCR, isothermal amplification and strand-displacement reaction. These detection circuits obtain the target signal via the replication of the target strand, the aggregation of the signal particles or the branch migration. Here we constructed a triode-like enzyme-free catalyst strand-displacement circuit for target DNA detection. The target strand triggered the reaction and released the fluorescence signal strand circularly through branch migration. However, the main challenge of strand-displacement reaction is the signal leakage. Therefore, we designed a double strand structure “junction fuel”, which was used to increase the binding energy across the displacement process. Ultimately, the leakage of the system obtained stable inhabitation due to the junction fuel strand. The limit of detection of the system was as low as 0.11 nmol/L and the gain of the system was as high as 28-fold(the concentration of target was 50 nmol/L). Furthermore, the process of the system was visualized vividly in the reaction curve through the kinetic simulation implemented, which suggests that the combination of the kinetic simulation and the experiment exhibits a promising prospect towards the use of strand-displacement circuit in analytical, diagnostic application and synthetic biology.

Complex structural Si3N4 ceramics with ultra-high porosity were innovatively formed by selective laser sintering (SLS) technology without any binder. Due to rapid cooling rate, the high temperature phase constituent and microstructure of the SLSed Si3N4 poly hollow microspheres (PHMS) were preserved, thus revealing the bonding mechanism of Si3N4 under the nonequilibrium heat source. Si3N4 PHMS are bonded by microvilli composed of bamboo-structure SiO2 nanofiber clusters, stacked SiO2 nanospheres and smooth α-Si3.72N4 nanowires. Finally, the pre-sintered Si3N4 ceramics with a porosity of 80% are directly fabricated in the atmosphere by SLS, which have the enough strength to satisfy the post-treatment requirements.

Objective: To construct a novel nanoplatform GNS@CaCO3/Ce6-NK by loading the CaCO3-coated gold nanostars (GNSs) withChlorin e6 molecules (Ce6) into human peripheral blood mononuclear cells (PBMCs)-derived NK cells for tumor targetedtherapy. Methods: GNS@CaCO3/Ce6 nanoparticles were prepared and characterized by TEM and UV-vis. The cell surface markers andcytokines secretion of NK cells before and after loading the GNS@CaCO3/Ce6 nanoparticles were detected by Flow Cytometry(FCM) and ELISA. Effects of the GNS@CaCO3/Ce6-NK cells on A549 cancer cells was determined by FCM and CCK-8.Intracellular fluorescent signals of GNS@CaCO3/Ce6-NK cells were detected via Confocal laser scanning microscopic (CLSM) andFCM at different time points. Intracellular ROS generation of GNS@CaCO3/Ce6-NK cells under laser irradiation were examinedby FCM. The distribution of GNS@CaCO3/Ce6-NK in A549 tumor-bearing mice were observed by fluorescence imaging and PAimaging. The combination therapy of GNS@CaCO3/Ce6-NK under laser irradiation were investigated on tumor-bearing mice. Results: The coated CaCO3 shell on the surface of GNSs exhibited prominent delivery and protection effect of Ce6 during thecellular uptake process. The as-prepared multifunctional GNS@CaCO3/Ce6-NK cells possessed bimodal functions of fluorescenceimaging and photoacoustic imaging. The as-prepared multifunctional GNS@CaCO3/Ce6-NK cells could actively target tumortissues with the enhanced photothermal/photodynamic therapy and immunotherapy. Conclusions: The GNS@CaCO3/Ce6-NK shows effective tumor-targeting ability and prominent therapeutic efficacy toward lungcancer A549 tumor-bearing mice. Through fully utilizing the features of GNSs and NK cells, this new nanoplatform provides anew synergistic strategy for enhanced photothermal/photodynamic therapy and immunotherapy in the field of anticancerdevelopment in the near future. Cite this article as: Liu B, Cao W, Cheng J, Fan S, Pan S, Wang L, et al.Human natural killer cells for targeting delivery of gold nanostars andbimodal imaging directed photothermal/photodynamic therapy andi m m u n o t h e r a p y . C a n c e r B i o l M e d . 2 0 1 9 ; 1 6 : 7 5 6 - 7 0 . d o i :10.20892/j.issn.2095-3941.2019.0112