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Regulating nonlinear optical (NLO) property of metal−organic frameworks (MOFs) is of pronounced significance for their scientific research and practical application, but the regulation through external stimuli is still a challenging task. Here we prepare and electrically control the nonlinear optical regulation of conductive MOFs Cu-HHTP films with [001]- (Cu-HHTP[001]) and [100]-orientations (Cu-HHTP[100]). Z-scan results show that the nonlinear absorption coefficient (β) of Cu-HHTP[001] film (7.60 × 10−6 m/W) is much higher than that of Cu-HHTP[100] film (0.84 × 10−6 m/W) at 0 V and the β of Cu-HHTP[001] and Cu-HHTP[100] films gradually increase to 3.84 × 10−5 and 1.71 × 10−6 m/W at 10 V by increasing the applied voltage, respectively. Due to 2D Cu-HHTP having anisotropy of charge transfer in different orientations, the NLO of MOFs film can be dependent on their growth orientations and improved by tuning the electrical field. This study provides more avenues for the regulation and NLO applications of MOFs. Nonlinear optical properties of metal-organic framework can be tuned for potential optical applications. Here the authors demonstrate an enhancement the nonlinear absorption coefficient of MOF film by applying external electric field. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The elastodynamic responses of the multilayered transversely isotropic medium subjected to uniform pressures occupying a rectangular flexible domain are precisely investigated by virtue of the precise integration approach (PIA) and the mixed dual vector technique. The dynamic rectangular distributed loadings are prescribed either at the external surface or within the stratified soil. The axes of material symmetry for different strata are assumed to be normal to the interfaces of adjacent layers and thus parallel with each other. As for the introduced technology, there is no limit of the thickness and number of soil layers to be discussed. The classical two-dimensional Fourier integral transformation is applied to convert the governing partial differential equilibrium equations corresponding to elastic displacements in the Cartesian coordinate system, and a set of easily solved second-order ordinary differential equations are acquired. Aided by the mixed dual vectors, the second-order ordinary differential equations are further reduced into first-order ordinary differential matrix equation and its general solution is analytically expressed as the exponential matrix. The PIA is adopted to estimate the changing patterns of displacement components by means of solving the exponential matrix in the Fourier-transformed domain. As a highly precise methodology, the PIA is advantageous to obtain the dynamic solutions with any desired accuracy. The physical-domain counterpart is then derived with the aid of the double Fourier inverse transform. Finally, comparisons with existing numerical results are provided to validate the high accuracy of the employed scheme. Selected numerical examples are presented to portray the dependence of the dynamic responses of the multilayered media on material properties, thicknesses, frequencies of excitation and dimensions of the loading size. [ABSTRACT FROM AUTHOR]

Screening ligands directly binding to an ensemble of intrinsically disordered proteins (IDP) to discover potential hits or leads for new drugs is an emerging but challenging area as IDPs lack well-defined and ordered 3D-protein structures. To explore a new IDP-based rational drug discovery strategy, a differential binding score (DIBS) is defined. The basis of DIBS is to quantitatively determine the binding preference of a ligand to an ensemble of conformations specified by IDP versus such preferences to an ensemble of random coil conformations of the same protein. Ensemble docking procedures performed on repeated sampling of conformations, and the results tested for statistical significance determine the preferential ligand binding sites of the IDP. The results of this approach closely reproduce the experimental data from recent literature on the binding of the ligand epigallocatechin gallate (EGCG) to the intrinsically disordered N-terminal domain of the tumor suppressor p53. Combining established approaches in developing a new method to screen ligands against IDPs could be valuable as a screening tool for IDP-based drug discovery. [ABSTRACT FROM AUTHOR]

This paper aims to conduct the free vibration analysis of single-layer and laminated composite plates with multiple cutouts based on the scaled boundary finite element method (SBFEM) incorporated with the precise integration method (PIM) and the technique of the degree of freedom transform. It is applicable to a variety of shaped plates containing cordiform, circular and other complicated cutouts. The key equations are formulated built on the two-dimensional model, and the discretization is carried out in terms of only three translational displacement components as the basic unknowns. The high-order spectral elements are applied in the proposed technique to accurately simulate the arc boundaries of cutouts. Characterized by the important semi-analytical feature of the SBFEM, responses of the transverse free vibration are accurately explored. The derivation of governing equations strictly follows the 3D theory of elasticity without introducing any assumptions. The general solution of the SBFEM key equation is in the form of the matrix exponent, which is calculated by the PIM. As a type of highly precise approach, the PIM is introduced to create the global stiffness matrix from the analytical exponential matrix, which can make sure the eigensolutions with enough accuracy. Aided by the methodology of the kinetic energy formula, the global mass matrix of the perforated plate structure is constructed. According to the thin plates, the degree of freedom transform is employed to lower the dimensions of eigenvalue equation and thus improve the computational efficiency. Numerical examples of flexible square and circular plates with various cutouts reveal that excellent agreement is achieved between the natural frequencies predicted by the developed method and those from other methods and exact solutions. Furthermore, the effect of boundary conditions, skew angles, thickness-to-length ratios and sizes of cutouts on distributions of vibration frequencies is discussed. [ABSTRACT FROM AUTHOR]

To evaluate safety and efficacy of one- vs. two-session radiofrequency ablation (RFA) of parathyroid hyperplasia for patients with secondary hyperparathyroidism (SHPT) and to compare the outcome of both methods on hypocalcemia. Patients with secondary hyperparathyroidism underwent ultrasound guided RFA of parathyroid hyperplasia. Patients were alternately assigned to either group 1 (n = 28) with RFA of all 4 glands in one session or group 2 (n = 28) with RFA of 2 glands in a first session and other 2 glands in a second session. Serum parathyroid hormone (PTH), calcium, phosphorus and alkaline phosphatase (ALP) values were measured at a series of time points after RFA. RFA parameters, including operation duration and ablation time and hospitalization length and cost, were compared between the two groups. Mean PTH decreased in group 1 from 1865.18 ± 828.93 pg/ml to 145.72 ± 119.27 pg/ml at 1 day after RFA and in group 2 from 2256.64 ± 1021.72 pg/ml to 1388.13 ± 890.15 pg/ml at 1 day after first RFA and to 137.26 ± 107.12 pg/ml at 1 day after second RFA. Group 1's calcium level decreased to 1.79 ± 0.31 mmol/L at day 1 after RFA and group 2 decreased to 1.89 ± 0.26 mmol/L at day 1 after second session RFA (P < 0.05). Multivariate analysis showed that hypocalcemia was related to serum ALP. Patients with ALP ≥ 566 U/L had lower calcium compared to patients with ALP < 566 U/L up to a month after RFA (P < 0.05). Group 1's RFA time and hospitalization were shorter and had lower cost compared with Group 2. US-guided RFA of parathyroid hyperplasia is a safe and effective method for treating secondary hyperparathyroidism. Single-session RFA was more cost-effective and resulted in a shorter hospital stay compared to two sessions. However, patients with two-session RFA had less hypocalcemia, especially those with high ALP. [ABSTRACT FROM AUTHOR]

An unbalanced pigment distribution among the sepal and petal segments results in various colour patterns of orchid flowers. Here, we explored this type of mechanism of colour pattern formation in flowers of the Cattleya hybrid 'KOVA'. Our study showed that pigment accumulation displayed obvious spatiotemporal specificity in the flowers and was likely regulated by three R2R3-MYB transcription factors. Before flowering, RcPAP1 was specifically expressed in the epichile to activate the anthocyanin biosynthesis pathway, which caused substantial cyanin accumulation and resulted in a purple-red colour. After flowering, the expression of RcPAP2 resulted in a low level of cyanin accumulation in the perianths and a pale pink colour, whereas RcPCP1 was expressed only in the hypochile, where it promoted α-carotene and lutein accumulation and resulted in a yellow colour. Additionally, we propose that the spatiotemporal expression of different combinations of AP3- and AGL6-like genes might participate in KOVA flower colour pattern formation. Li et al. provide insights on the color patterning process during flower development. They identify pigment components of the perianths and the lip segments in the Orchidaceae flowers and use transcriptome profiling and functional assays to identify genes involved in pigment biosynthesis and spatiotemporal specificity. [ABSTRACT FROM AUTHOR]

Pericyclic reactions are powerful transformations for the construction of carbon–carbon and carbon–heteroatom bonds in organic synthesis. Their role in biosynthesis is increasingly apparent, and mechanisms by which pericyclases can catalyse reactions are of major interest1. [4+2] cycloadditions (Diels–Alder reactions) have been widely used in organic synthesis2 for the formation of six-membered rings and are now well-established in biosynthesis3–6. [6+4] and other 'higher-order' cycloadditions were predicted7 in 1965, and are now increasingly common in the laboratory despite challenges arising from the generation of a highly strained ten-membered ring system8,9. However, although enzyme-catalysed [6+4] cycloadditions have been proposed10–12, they have not been proven to occur. Here we demonstrate a group of enzymes that catalyse a pericyclic [6+4] cycloaddition, which is a crucial step in the biosynthesis of streptoseomycin-type natural products. This type of pericyclase catalyses [6+4] and [4+2] cycloadditions through a single ambimodal transition state, which is consistent with previous proposals11,12. The [6+4] product is transformed to a less stable [4+2] adduct via a facile Cope rearrangement, and the [4+2] adduct is converted into the natural product enzymatically. Crystal structures of three pericyclases, computational simulations of potential energies and molecular dynamics, and site-directed mutagenesis establish the mechanism of this transformation. This work shows how enzymes are able to catalyse concerted pericyclic reactions involving ambimodal transition states. Enzymatic catalysis of pericyclic [6+4] cycloaddition reactions to form ten-membered rings is observed during biosynthesis of the macrocyclic antibiotic streptoseomycin, and the mechanism of these transformations is established. [ABSTRACT FROM AUTHOR]

Phenolic compounds are considered the main bioactive components in okra fruits. In order to well understand the accumulation pattern of phenolic compounds in okra fruits during maturation, and to obtain okra fruits with high level of health-beneficial phenolic compounds, physicochemical properties, phenolic profiles, antioxidant capacities, and inhibitory effects on digestive enzymes of okra fruits at different maturation stages were investigated. Noticeable variations in physicochemical properties and phenolic profiles of okra were observed at different maturation stages. Phenolic compounds, including quercetin-3-O-gentiobioside, quercetin-3-O-glucoside (isoquercitrin), rutin, quercetin derivative, protocatechuic acid, and catechin derivative, were determined to be the major compounds in okra fruits, while quercetin-3-O-gentiobioside was the most abundant phenolic compound. Considering the accumulation patterns of fruit size, firmness, and total flavonoid content of okra fruits, the optimal harvest time of okra fruits with relatively high level of health-beneficial phenolic compounds was determined. Furthermore, okra fruits at different maturation stages exerted remarkable antioxidant capacities and inhibitory effects on the pancreatic lipase, α-glucosidase, and α-amylase. The Pearson's correlation showed that quercetin-3-O-gentiobioside was one of the major contributors to the antioxidant capacities and inhibitory effects on digestive enzymes. Results are beneficial for understanding of the accumulation pattern of phenolic compounds in okra fruits during maturation, and can aid in the targeting of specific maturation stages with an optimal phenolic profile for the production of health-beneficial products. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Zhejiang University: Science B is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The convex and concave relaxation procedure (CCRP) was recently proposed and exhibited state-of-the-art performance on the graph matching problem. However, CCRP involves explicitly both convex and concave relaxations which typically are difficult to find, and thus greatly limit its practical applications. In this paper we propose a simplified CCRP scheme, which can be proved to realize exactly CCRP, but with a much simpler formulation without needing the concave relaxation in an explicit way, thus significantly simplifying the process of developing CCRP algorithms. The simplified CCRP can be generally applied to any optimizations over the partial permutation matrix, as long as the convex relaxation can be found. Based on two convex relaxations, we obtain two graph matching algorithms defined on adjacency matrix and affinity matrix, respectively. Extensive experimental results witness the simplicity as well as state-of-the-art performance of the two simplified CCRP graph matching algorithms. [ABSTRACT FROM AUTHOR]

LiMnNiO is synthesized by a sol-gel method and the intercalation kinetics as positive electrode for lithium-ion batteries is investigated by EIS. LiMnNiO particles prepared via sol-gel process possess spinel phase with Fd-3m space group. The charge-transfer resistance, the exchange-current density and the solid-phase diffusion are found as a function of temperature. The apparent activation energy of the exchange current, the charge transfer, and the lithium diffusion in solid phase are also determined, respectively. This result indicates that the effect of the temperature on the cell capacity and the current dependence of the capacity results mainly from the enhancement of the lithium diffusion at elevated temperatures. It can be concluded that LiMnNiO cell has a bad rate cycling performance at elevated temperatures before any modification due to the high diffusion apparent activation energy. The relevant theoretical elucidations thus provide us some useful insights into the design of novel LiMnNiO-based positive-electrode materials. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to investigate the effects of a zinc-substituted nano-hydroxyapatite (Zn-HA) coating, applied by an electrochemical process, on implant osseointegraton in a rabbit model. Methods: A Zn-HA coating or an HA coating was deposited using an electrochemical process. Surface morphology was examined using field-emission scanning electron microscopy. The crystal structure and chemical composition of the coatings were examined using an X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). A total of 78 implants were inserted into femurs and tibias of rabbits. After two, four, and eight weeks, femurs and tibias were retrieved and prepared for histomorphometric evaluation and removal torque (RTQ) tests. Results: Rod-like HA crystals appeared on both implant surfaces. The dimensions of the Zn-HA crystals seemed to be smaller than those of HA. XRD patterns showed that the peaks of both coatings matched well with standard HA patterns. FTIR spectra showed that both coatings consisted of HA crystals. The Zn-HA coating significantly improved the bone area within all threads after four and eight weeks ( P<0.05), the bone to implant contact (BIC) at four weeks ( P<0.05), and RTQ values after four and eight weeks ( P<0.05). Conclusions: The study showed that an electrochemically deposited Zn-HA coating has potential for improving bone integration with an implant surface. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze the effect of strontium-substituted hydroxyapatite (Sr-HA) on bone osseointegration of the implants using fluorescence microscopy. We allocated 20 implants to two groups: Sr-HA group and HA group. Electrochemically deposited HA and Sr-HA coatings were applied onto the implants separately. All the implants were inserted into femur bone of rabbits. Oxytetracycline hydrochloride, alizarin-complexon, and calcein green were respectively administered 7, 28, and 46 d after the implantation. After eight weeks, femurs were retrieved and prepared for the fluorescence microscopy observation. We analyzed the bone mineral apposition rates (MARs), bone area ratios (BARs), and bone to implant contact (BIC) of the two groups. Fluorescence microscopic observation showed that all groups exhibited extensive early peri-implant bone formation. The MAR of the Sr-HA group was greater than that for pure HA from 7 to 28 d after implantation, but no significant difference was found at later stage. And the BIC showed difference at 7 and 28 d compared with pure HA. We concluded that Sr-HA coating can improve the bone osseointegration of the implant in the early stage compared with the HA coating. [ABSTRACT FROM AUTHOR]

Sensorless manipulation strategies have been successfully used in the precision robotic assembly. Most previous work in this area has concentrated on inserting a peg into a fixed hole. However, in some cases, e.g., the assembly of piston-peg-rod of the automotive engine, due to the motion of piston, the position of the hole in piston is hard to be fully constrained. The purpose of this paper is to give a novel sensorless manipulation strategy for the high-precision assembly of a peg into an unfixed hole. Firstly, a decomposition method of the high-dimensional configuration space of the peg hole is analyzed. Subsequently, the robotic manipulations are proposed in the two low-dimensional spaces decomposed from the high-dimensional configuration space. Then, the attractive regions formed in the two sub-spaces are constructed, thus, the position and orientation uncertainties of the peg hole can be eliminated by the attractive regions and the robotic manipulations. Finally, a typical industry application, fitting a peg into an unfixed piston rod hole of the automotive engine, is used to validate the presented strategy. [ABSTRACT FROM AUTHOR]

LiFePO-positive electrode material was successfully synthesized by a solid-state method, and the effect of storage temperatures on kinetics of lithium-ion insertion for LiFePO-positive electrode material was investigated by electrochemical impedance spectroscopy. The charge-transfer resistance of LiFePO electrode decreases with increasing the storage temperatures. This suggests that it has a high electrochemical activity at high temperature. The diffusion coefficient of lithium ion is greatly increased with increasing the storage temperatures, indicating that the kinetics of Li and electron transfer into the electrodes were much fast at high storage temperature. [ABSTRACT FROM AUTHOR]

Cucumber ( Cucumis sativus L.) has served as a model to understand hormone regulation in unisexual flower development since the 1950s and the role of ethylene in promoting female flower development has been well documented. Recent studies cloned the F-locus in gynoecious lines as an additional copy of the ACC synthase (ACS) gene, which further confirmed the role of ethylene in the promotion of female cucumber flowers. However, no direct evidence was generated to demonstrate that increases in endogenous ethylene production could induce female flowers by arresting stamen development. To clarify the relationship between ethylene production and stamen development, we overexpressed the ethylene synthesis cucumber gene CsACO2 to generate transgenic Arabidopsis, driven by the organ-specific promoter P AP3 . We found that organ-specific overexpression of CsACO2 significantly affected stamen but not carpel development, similar to that in the female flowers of cucumber. Our results suggested that increases in ethylene production directly disturb stamen development. Additionally, our study revealed that among all floral organs, stamens respond most sensitively to exogenous ethylene. [ABSTRACT FROM AUTHOR]

In the era of increased antibiotic resistance and ever-stricter control on antibiotic use, it is urgent to develop green, safe, and non-residue alternatives to antibiotics applied to the poultry industry. To this end, we supplied the potential Lactobacillus plantarum (L. plantarum) fermented Astragalus in the diet of laying hens, with a final addition of 3‰. Its effects have been assessed on laying performance, egg quality, antioxidant and immunological status, and intestinal microbiota, and are compared to the control group, to the Astragalus group containing 3‰ unfermented Astragalus, and to the L. plantarum group containing 2% L. plantarum [5 × 108 colony-forming unit (CFU) per milliliter (mL)]. During the second half of the experimental period (15 to 28 days), the egg production rate was considerably higher in the fermented Astragalus group than that in the other groups, with the fermented Astragalus group having the lowest feed conversion ratio. No significant difference (P > 0.05) was noted among treatments on egg quality. Fermented Astragalus-treated hens exhibited significantly increased catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in serum, and reduced malondialdehyde (MDA) in serum. Furthermore, fermented Astragalus supplementation resulted in a significant increase in ileal microbiota abundance relative to control. In conclusion, feeding laying hens with L. plantarum fermented Astragalus has beneficial effects on production, antioxidant potential, immunity, and ileal microbiota. L. plantarum fermented Astragalus is expected to be a novel feed additive used in poultry production. [ABSTRACT FROM AUTHOR]

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper. [ABSTRACT FROM AUTHOR]

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, and its incidence rate is rapidly growing. It is necessary to understand the pathogenesis of PTC to develop effective diagnosis methods. Promoter methylation has been recognized to contribute to the alterations in gene expression observed in tumorigenesis. Our RNA-seq data identified 1191 differentially expressed mRNAs and 147 differentially expressed lncRNAs in PTC. Next, promoter methylation of these genes was detected by reduced representation bisulfite sequencing (RRBS) technology and comprehensively analyzed to identify differential methylation. In total, 14 genes (13 mRNAs and 1 lncRNA), in which methylation was intimately involved in regulating gene expression, were proposed as novel diagnostic biomarkers. To gain insights into the relationships among these 14 genes, a core co-function network was constructed based on co-expression, co-function and co-methylation data. Notably, CXCL12 was identified as an essential gene in the network that was closely connected with the other genes. These data suggested that CXCL12 down-regulation in PTC may be caused by promoter hypermethylation. Our study was the first to perform an RRBS analysis for PTC and suggested that CXCL12 may contribute to PTC development by methylation-mediated epigenetic regulation of gene expression. [ABSTRACT FROM AUTHOR]

Molybdenum disulphide (MoS2), which is a typical semiconductor from the family of layered transition metal dichalcogenides (TMDs), is an attractive material for optoelectronic and photodetection applications because of its tunable bandgap and high quantum luminescence efficiency. Although a high photoresponsivity of 880-2000 AW−1 and photogain up to 5000 have been demonstrated in MoS2-based photodetectors, the light absorption and gain mechanisms are two fundamental issues preventing these materials from further improvement. In addition, it is still debated whether monolayer or multilayer MoS2 could deliver better performance. Here, we demonstrate a photoresponsivity of approximately 104 AW−1 and a photogain of approximately 107 electrons per photon in an n-n heterostructure photodetector that consists of a multilayer MoS2 thin film covered with a thin layer of graphene quantum dots (GQDs). The enhanced light-matter interaction results from effective charge transfer and the re-absorption of photons, leading to enhanced light absorption and the creation of electron-hole pairs. It is feasible to scale up the device and obtain a fast response, thus making it one step closer to practical applications. [ABSTRACT FROM AUTHOR]