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In this article the catalytic mechanism for H2 evolution via water splitting at the expense of B2(OH)4 catalyzed by acid, base or metal nanoparticles was investigated by density functional theory (DFT) calculations.

The development of deep learning models in medical image analysis is majorly limited by the lack of large-sized and well-annotated datasets. Unsupervised learning does not require labels and is more suitable for solving medical image analysis problems. However, most of the current unsupervised learning methods need to be applied to large datasets. To make unsupervised learning applicable to small datasets, we proposed Swin MAE, which is a masked autoencoder with Swin Transformer as its backbone. Even on a dataset of only a few thousand medical images and without using any pre-trained models, Swin MAE is still able to learn useful semantic features purely from images. It can equal or even slightly outperform the supervised model obtained by Swin Transformer trained on ImageNet in terms of the transfer learning results of downstream tasks. The code is publicly available at https://github.com/Zian-Xu/Swin-MAE.

Hypersonic vehicles are an important development direction in aerospace, and their development will have a significant impact on world security, the development of cosmic space resources and related disciplines. Along with the rapid development of modern aircraft, landing gear is commonly used with retractable technology, which brings a series of problems, such as the design of landing gear hatch retraction heat sealing mechanism and the evaluation of air tightness. This paper takes the thermal sealing structure of the front main landing gear hatch of a vehicle as an example, reviews the progress of the analysis techniques of sealing material properties and sealing structure design for hypersonic vehicles at home and abroad, discusses the current status of the development and limitations of hatch thermal sealing technology, outlines and discusses the key technologies for design and analysis of hatch thermal sealing structure and the future development trend, and summarizes the test equipment and methods for identifying the performance of seals and sealing systems.

ANO1, anoctamin 1(also known as TMEM16A), is the molecular basis of calcium-activated chloride channels with ten transmembrane segments which are widely expressed in mammalian cells, including epithelial cells, vascular smooth muscle tissues, electro-excitatory cells, and some tumor cells. These proteins are widely expressed in mammalian cells, including epithelial cells, vascular smooth muscle tissues, electro-excitatory cells, and some tumor cells. To date, multiple studies have shown that many natural and synthetic compounds have regulatory effects on ANO1. Therefore, ANO1 could be a potential new drug target for the treatment of cancer, pain, diarrhea, hypertension, and asthma. Here we review the structure of ANO1 and its involvement in cancer, pain, diarrhea, hypertension, and asthma.

Predicting engineering students’ academic performance is crucial for teachers to implement teaching interventions. How to use students’ behavior records to predict grades during school has attracted extensive attention from researchers. Various machine learning methods have been proposed by previous researchers to predict engineering students’ academic performance through their learning records. However, one of the major challenges now is that many researchers ignore the problem of reduced accuracy of prediction models due to imbalanced data. Simultaneously, a single classifier is susceptible to data changes and has an unstable classification performance. To this end, this paper proposes the RBF-Naive Bayes (RBFNB) prediction model to predict students’ academic performance, which integrates Radial Basis Function (RBF) Network algorithm and Naive Bayes algorithm. The method of RBF Network is applied to predict the academic performance of students and generate prediction results. Then, the method of Naive Bayes is adopted to correct the previous prediction results for improving the accuracy of the prediction. The proposed RBFNB prediction model was applied to the data set about the engineering students’ academic performance from a university and the Kalboard 360 public data set, respectively.

The detection of phytohormones in real time has attracted increasing attention because of their critical roles in regulating the development and signaling of plants, especially in defense against biotic stresses. Herein, stainless steel sheet electrodes modified with carbon cement were coupled with paper-based analysis devices for direct and simultaneous detection of salicylic acid (SA) and indole-3-acetic acid (IAA) in plants. We demonstrated that the excellent conductivity of stainless steel sheet electrodes enabled us to simultaneously differentiate IAA and SA at a level of 10 nM. With our approach, the content of IAA and SA in Arabidopsis thaliana leaves infected or not infected with Pst DC3000 could be rapidly quantified at the same time. Our experimental results on differentiation of IAA and SA at different time points showed that there were antagonistic interactions between the IAA and SA after infection of Arabidopsis leaves with Pst DC3000. By offering a cost-effective approach for rapid and sensitive detection of IAA and SA, this study suggests that electrochemical detection can be used in the study and development of precision agriculture technology.

Influenza A virus poses a constant challenge to human health. The highly conserved influenza matrix-2 (M2) protein is an attractive target for the development of a universal antibody-based drug. However, screening using antigens with subphysiological conformation in a nonmembrane environment significantly reduces the generation of efficient antibodies. Here, M2(1-46) was incorporated into nanodiscs (M2-nanodiscs) with M2 in a membrane-embedded tetrameric conformation, closely resembling its natural physiological state in the influenza viral envelope. M2-nanodisc generation, an antigen, was followed by

The magnetic properties of the magnetic transparent composite films largely depend on the content of Fe3O4 employed. However, higher addition of Fe3O4 into the matrix will lead to Fe3O4 nanoparticles agglomeration resulting in the reduction in the transparency of the composite films. The contradiction between Fe3O4 nanoparticle content and transparency limits the application of transparent magnetic films. In this work, the spherical bamboo nanocellulose (SBN) with an average size of 61 nm was prepared from bamboo powder by NaOH/Urea/Thiourea aqueous system, which was an effective, inexpensive and less toxic strategy. The basic structure of SBN was investigated. The SBN exhibited the cellulose II type crystal structure. The molecular chain length of SBN were lower than before dissolution. The magnetic SBN/Fe3O4 composite films with light penetration were prepared. The results revealed that the dispersion of Fe3O4 nanoparticles in the SBN/Fe3O4 composite films was much better than that in nanofibrillated cellulose (NFC)/Fe3O4 composite films because of the abundant hydrogen bonds between Fe3O4 nanoparticles and SBN. The transparent results indicated the highest transmittance of the films was 94% in the wavelength range of visible light, which was almost 23.7% higher than that of NFC/Fe3O4 composite films with the same amount of Fe3O4 addition (15 wt%). The findings in this study also revealed that the SBN in the SBN/Fe3O4 composite films was distributed in layers. The saturation magnetization of the SBN/Fe3O4 composite films was 10.65 emu g−1 with 15 wt% Fe3O4 incorporated, which guaranteed the excellent magnetic properties.

Both Colony‐stimulating factor 1 receptor (CSF1R) and triggering receptor expressed on myeloid cells‐2 (TREM2) are trans‐membrane receptors and are expressed in the brain primarily by microglia. Mutations in these two microglia‐expressed genes associated with neurodegenerative disease have recently been grouped under the term “microgliopathy”. Several literatures have indicated that CSF1R and TREM2 encounters a stepwise shedding and TREM2 variants impair or accelerate the processing. However, whether CSF1R variant affects the shedding of CSF1R remains elusive. Here, plasmids containing human CSF1R or TREM2 were transiently transfected into the human embryonic kidney (HEK) 293T cells. Using Western Blot and/or ELISA assay, we demonstrated that, similar to those of TREM2, an N‐terminal fragment (NTF) shedding of CSF1R ectodomain and a subsequent C‐terminal fragment (CTF) of CSF1R intra‐membrane were generated by a disintegrin and metalloprotease (ADAM) family member and by γ‐secretase, respectively. And the shedding was inhibited by treatment with Batimastat, an ADAM inhibitor, or DAPT or compound E, a γ‐secretase inhibitor. Importantly, we show that the cleaved fragments, both extracellular domain and intracellular domain of a common disease associated I794T variant, were decreased significantly. Together, our studies demonstrate a stepwise approach of human CSF1R cleavage and contribute to understand the pathogenicity of CSF1R I794T variant in adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). These studies also suggest that the cleaved ectodomain fragment released from CSF1R may be proposed as a diagnostic biomarker for ALSP.

Extractive distillation (ED) can be used to separate mixtures with low relative volatilities that are even close to unity. It is widely adopted for the separation of aromatics and nonaromatics in t...

Background Immune complexes (ICs) bind to and activate platelets via FcγRIIA, causing patients to experience thrombocytopenia, as well as an increased risk of forming occlusive thrombi. Although platelets have been shown to mediate IC-induced pathologies, the mechanisms involved have yet to be fully elucidated. We identified that apoptosis signal-regulating kinase 1 (ASK1) is present in both human and mouse platelets and potentiates many platelet functions. Objectives Here we set out to study ASK1's role in regulating IC-mediated platelet functions in vitro and IC-induced pathologies using an in vivo mouse model. Methods Using human platelets treated with an ASK1-specific inhibitor and platelets from FCGR2A/Ask1-/- transgenic mice, we examined various platelet functions induced by model ICs in vitro and in vivo. Results We found that ASK1 was activated in human platelets following cross-linking of FcγRIIA using either anti-hCD9 or IV.3 + goat-anti-mouse. Although genetic deletion or inhibition of ASK1 significantly attenuated anti-CD9-induced platelet aggregation, activation of the canonical FcγRIIA signaling targets Syk and PLCγ2 was unaffected. We further found that anti-mCD9-induced cPla2 phosphorylation and TxA2 generation is delayed in Ask1 null transgenic mouse platelets leading to diminished δ-granule secretion. In vivo, absence of Ask1 protected FCGR2A transgenic mice from thrombocytopenia, thrombosis, and systemic shock following injection of anti-mCD9. In whole blood microfluidics, platelet adhesion and thrombus formation on fibrinogen was enhanced by Ask1. Conclusions These findings suggest that ASK1 inhibition may be a potential target for the treatment of IC-induced shock and other immune-mediated thrombotic disorders.

The unique and efficient characteristics of allelopathy in submerged plants make it an environmentally friendly method to control harmful algal blooms. Increased research focus has been placed on the improved allelochemical extraction methods of submerged plants because of their cost-utility relationships. In this study, the growth inhibition effect of Vallisneria extract on Microcystis aeruginosa (M. aeruginosa) cells through the combination of enzyme and ultrasonic-assisted extraction method was analyzed. By establishing a co-cultivation experiment, the growth indicators, photosynthetic system, and oxidative stress system of M. aeruginosa were determined. The reactive oxygen species (ROS) and superoxide dismutase (SOD) activity, as well as the catalase (CAT) and Malondialdehyde (MDA) levels of algal cells were found to have increased significantly after co-cultivation, which indicated that the Vallisneria ultrasonic-cellulase extract could induce oxidative stress in Microcystis aeruginosa cells. The Vallisneria extract could promote at low concentrations and inhibit at high concentrations on the growth of Microcystis aeruginosa. The effective suppression of growth of algae cells with the extract was observed at 5 g/L (fresh weight). The results showed that the Vallisneria ultrasonic-cellulase extract had a significant inhibitory effect on M. aeruginosa, making the effective ingredients a useful reference for algae inhibitors.

An ANN-based QoT estimator with asymmetric loss function is proposed. It enables efficient assignment of modulation format, which increases network capacity compared to the model trained based on the symmetric loss function in test networks.

Fibroblast growth factor receptor type 2 (FGFR2) has emerged as a key oncogenic factor that regulates gastric cancer (GC) progression, but the underlying mechanism of FGF–FGFR2 signaling pathway remains largely unknown. To identify the potential molecular mechanisms of the oncogenic FGFR2 in gastric carcinogenesis and convey a novel therapeutic strategy, we profiled the FGFR alterations and analyzed their clinical associations in TCGA and Hong Kong GC cohorts. We found that FGFR2 overexpression in GC cell lines and primary tumors predicted poor survival and was associated with advanced stages of GC. Functionally, growth abilities and cell cycle progression of GC were inhibited by inactivation of ERK–MAPK signal transduction after FGFR2 knockdown, while apoptosis was promoted. Meanwhile, the first-line anti-cancer drug sensitivity was enhanced. RNA-seq analysis further revealed that YAP1 signaling serves as a significant downstream modulator and mediates the oncogenic signaling of FGFR2. When stimulating FGFR2 by rhFGF18, we observed intensified F-actin, nuclear accumulation of YAP1, and overexpression of YAP1 targets, but these effects were attenuated by either FGFR2 depletion or AZD4547 administration. Additionally, the FGF18–FGFR2 signaling upregulated YAP1 expression through activating c-Jun, an effector of MAPK signaling. In our cohort, 28.94% of GC cases were characterized as FGFR2, c-Jun, and YAP1 co-positive and demonstrated worse clinical outcomes. Remarkably, we also found that co-targeting FGFR2 and YAP1 by AZD4547 and Verteporfin synergistically enhanced the antitumor effects in vitro and in vivo. In conclusion, we have identified the oncogenic FGF–FGFR2 regulates YAP1 signaling in GC. The findings also highlight the translational potential of FGFR2–c-Jun–YAP1 axis, which may serve as a prognostic biomarker and therapeutic target for GC.

We study shot noise processes when the shot noises are weakly dependent, satisfying the ρ-mixing condition. We prove a functional weak law of large numbers and a functional central limit theorem for this shot noise process in an asymptotic regime with a high intensity of shots. The deterministic fluid limit is unaffected by the presence of weak dependence. The limit in the diffusion scale is a continuous Gaussian process whose covariance function explicitly captures the dependence among the noises. The model and results can be applied in financial and insurance risks with dependent claims as well as queueing systems with dependent service times. To prove the existence of the limit process, we employ the existence criterion that uses a maximal inequality requiring a set function with a superadditivity property. We identify such a set function for the limit process by exploiting the ρ-mixing condition. To prove the weak convergence, we establish the tightness property and the convergence of finite dimensional distributions. To prove tightness, we construct two auxiliary processes and apply an Ottaviani-type inequality for weakly dependent sequences.

Hippo signaling functions to limit cellular growth, but the aberrant nuclear accumulation of its downstream YAP1 leads to carcinogenesis. YAP1/TEAD complex activates the oncogenic downstream transcription, such as CTGF and c-Myc. How YAP1 is protected in the cytoplasm from ubiquitin-mediated degradation remains elusive. In this study, a member of Angiomotin (Motin) family, AMOTL1 (Angiomotin Like 1), was screened out as the only one to promote YAP1 nuclear accumulation by several clinical cohorts, which was further confirmed by the cellular functional assays. The interaction between YAP1 and AMOTL1 was suggested by co-immunoprecipitation and immunofluorescent staining. The clinical significance of the AMOTL1–YAP1–CTGF axis in gastric cancer (GC) was analyzed by multiple clinical cohorts. Moreover, the therapeutic effect of targeting the oncogenic axis was appraised by drug-sensitivity tests and xenograft-formation assays. The upregulation of AMOTL1 is associated with unfavorable clinical outcomes of GC, and knocking down AMOTL1 impairs its oncogenic properties. The cytoplasmic interaction between AMOTL1 and YAP1 protects each other from ubiquitin-mediated degradation. AMOTL1 promotes YAP1 translocation into the nuclei to activate the downstream expression, such as CTGF. Knocking down AMOTL1, YAP1, and CTGF enhances the therapeutic efficacies of the first-line anticancer drugs. Taken together, AMOTL1 plays an oncogenic role in gastric carcinogenesis through interacting with YAP1 and promoting its nuclear accumulation. A combination of AMOTL1, YAP1, and CTGF expression might serve as a surrogate of Hippo activation status. The co-activation of the AMOTL1/YAP1–CTGF axis is associated with poor clinical outcomes of GC patients, and targeting this oncogenic axis may enhance the chemotherapeutic effects.

The dynamic modeling for the foldable origami space membrane structure considering contact-impact during the deployment is studied in this paper. The membrane is discretized using the triangular elements of the Absolute Nodal Coordinate Formulation (ANCF), and the stress–strain relationship of the membrane is determined based on the Stiffness Reduction Model (SRM). A mixed method is proposed for the frictionless contact problem by combining the membrane surface-to-surface (STS) contact elements with the membrane node-to-surface (NTS) contact elements to improve precision. Compared with the traditional STS contact elements, the mixed method can effectively avoid mutual penetration of the element boundaries, especially for the foldable origami membrane structures undergoing overall motions. The penalty method is adopted to enforce the nonpenetration condition. Moreover, special constraints are built for the fold lines, and then the dynamic equations of the membrane multibody system considering the damping effect are formulated. The dynamic deployment procedure of a leaf-in origami membrane structure with contact-impact is performed employing this present mixed method. The results demonstrate the effectiveness and superiority of the presented mixed method in the solution of the complicated contact problem, and the influence of the contact-impact on the dynamic performance is analyzed.

Graphite-like carbon nitride (OCN) synthesized by partial oxygenation was decorated with lipophilic oleic diethanolamide borate (ODAB) groups via a reflux reaction. The as-modified ODAB-OCN nanosheets could achieve a high degree of dispersion in paraffin oil due to the intercalation of oil-friendly ODAB groups between the nanosheet layers. Notably, the results of the friction experiments revealed that ODAB-OCN, a lubricant additive, possessed excellent tribological properties. Unlike the results for pure oil, the average friction coefficient and wear rate for 0.20 wt% ODAB-OCN included in the oil decreased by 22.7% and 90.8%, respectively. This work will be of great significance for the application of graphite-like carbon nitride (g-C3N4) as an oil-based lubricant additive.

The high Zn ion desolvation energy, sluggish Zn deposition kinetics, and top Zn plating pattern are the key challenges toward practical Zn anodes. Herein, these key issues are addressed by introducing zinc pyrovanadate (ZVO) as a solid zinc-ion conductor interface to induce smooth and fast Zn deposition underneath the layer. Electrochemical studies, computational analysis, and in situ observations reveal the boosted desolvation and deposition kinetics, and uniformity by ZVO interface. In addition, the anti-corrosion ability of Zn anodes is improved, resulting in high Zn stripping/plating reversibility. Consequently, the ZVO layer renders fast rechargeability and durable life in both Zn symmetric cells (1050 h at 10 mA cm

Using network flying platforms (NFPs) as aerial relays has been emerging as a promising solution for mobile backhaul frameworks in fifth generation and beyond wireless networks. Moreover, free space optics (FSO) technology has become the alternative to radio frequency technology for backhaul links due to its advantages of a high data rate, long transmission range, and negligible interference. In an FSO-based NFP relay backhaul network, due to the fragility of FSO links, how to deploy NFPs to satisfy network traffic demands is a challenging problem. Moreover, the establishment of non-essential FSO links leads to the extra deployment of NFPs due to the limited number of transceivers carried by each NFP, which makes the NFP deployment problem more complex. To solve these issues, we jointly consider the deployment of NFPs and the formation of network topology, the targets of which are to minimize the number of deployed NFPs and network congestion. The problem is formulated as mixed-integer nonlinear programming, which is hard to solve directly, and we linearize it based on transmission range simplification. A heuristic algorithm is proposed to solve the problem for large-scale network scenarios. Simulation results show that the joint optimization scheme of NFP deployment and network topology formation surpasses the single optimization scheme, and the proposed heuristic algorithm can solve the joint optimization problem efficiently in differently scaled networks.

State of charge (SOC) is an important indicator to describe battery performance. However, most of the training input data for SOC estimation using deep learning algorithm do not consider the battery internal resistance. In this paper, a method for SOC estimation of lithium-ion batteries based on the LSTM neural network is proposed, and the battery voltage, current, temperature and internal resistance are taken as the training input data of the LSTM model. When the correlation function is determined, the influence of different hyperparameters of the LSTM model with battery internal resistance as the training data on the SOC estimation results is analyzed and compared to determine the optimal setting of the hyperparameters of the model. The experimental results show that the model with the battery resistance as the training input data has higher accuracy. On this basis, the LSTM model with appropriate hyperparameters has the advantages of high accuracy and fast convergence in SOC estimation.

In this paper, a trajectory generation strategy that is conducive to quadrotor and load stability are presented for a quadrotor unmanned aerial vehicle (UAV) with cable suspended load. First, the Euler-Lagrange formulation is used to obtain the dynamic model of the system, where the integrated dynamics of the quadrotor and cable suspended load are considered. Second, the differential flatness is used to generate trajectory that is conducive to quadrotor and load stability. Finally, the system is divided into two parts: a full-drive part and an under-actuation part, and a sliding mode controller is designed to restrain the attitude change caused by the swing of the load. Numerical simulation results using quadrotor and load attitude change are shown to evaluate the proposed control law.

Underwater structural defects in hydraulic tunnels are highly concealed and difficult to be identified by conventional manual methods. Remotely operated vehicle combined with visible light cameras can provide a noncontact and high spatial resolution damage detection solution. However, manually extracting useful structural damage-related information from massive data is time-consuming and involves high labor cost. This article proposes an integrated pixel-level underwater structural multi-defects instance segmentation and quantification framework for hydraulic tunnels via machine vision and deep learning. Firstly, a tunnel lining underwater structural multi-defects video dataset is developed. Next, an improved You Only Look At CoefficienTs for Edge devices is used to build the detector by exploiting temporal redundancy in videos. Three backbone detectors are used to trade off the balance between detection accuracy and efficiency, and a cross-domain transfer learning strategy is introduced to reduce model training costs and data dependencies. Various complicated tunnel underwater inspection scenarios, including uneven illumination, tilt shooting, high brightness, and motion blur scenarios, are used to evaluate model generalization capability. Experimental results show that ResNet50-based YolactEdge can well trade off the balance between accuracy and speed, which achieves 92.47 bbox mAP, 92.15 mask mAP, and 39.27 FPS in the testing set. A quantification evaluation method is proposed to quantify the detection results and extract the geometric features of structural defects based on digital image processing techniques. The proposed method can accurately identify the number, size, and area of tunnel underwater structural defects, providing data support for subsequent reinforcement.

Background: All-terrain vehicles are mostly used in poor driving environments. A key part of the suspension mechanism of all-terrain vehicles, the lower control arm, bears various loads when the vehicle is driving. This component is prone to be fatigue and failure, which affects the performance of the entire vehicle. Therefore, in order to improve the performance of all-terrain vehicles, the fatigue life of the lower control arm was studied based on the measured force load spectrum. Methods: Firstly, the finite element model of the lower control arm is established, the free modal simulation analysis is carried out, and the experimental research is carried out by building a modal test system. Then combining the calculated modal and experimental modal results, the finite element model is verified. Next, through the road load spectrum acquisition test in the automobile proving ground, the force time history of the lower control arm is obtained, and the signal is processed and analyzed to verify the reliability of the force load signal. On this basis, the boundary constraints of the lower control arm are established based on the actual working conditions of the all-terrain vehicle, and the dynamics simulation analysis is carried out with the measured force as input. Finally, according to stress-strain signal in dynamic analysis results, combining the modified local stress-strain method and the Landgrave damage criterion, the fatigue life of the lower control arm is calculated. Results: The minimum fatigue cycle life of the lower control arm on the test roads is 3.56×105 km, and its fatigue life meets the design and use requirements. Conclusions: The result shows that based on the actual driving load spectrum, the actual driving fatigue life can be calculated and forecasted more accurately.

Novel pleuromutilin derivatives with 3,4-dihydropyrimidin and pyrimidine moieties were designed, synthesized, and evaluated for their antibacterial activities. Most of the synthesized derivatives, especially the compounds bearing the pyrimidine moieties, exhibited potent antibacterial activities against methicillin-resistant Staphylococcus aureus BNCC 337371 (MRSA-337371), Staphylococcus aureus ATCC 25923 (S. aureus-25923) and methicillin-resistant Staphylococcus epidermidis ATCC 51625 (MRSE-51625). Compounds 5a, 5g and 5h exerted the excellent antibacterial activities and selected to evaluate their bacterial killing kinetics. Compound 5h displayed the highest antibacterial activities with bacteriostatic activities against MRSA and further evaluated its efficacy in mouse systemic infection. The results showed that compound 5h exhibited potent in vivo antibacterial effects to significantly improve the survival rate of mice (ED

In order to reduce the infection rate of major respiratory diseases, it is crucial to development of masks with antibacterial functions. This paper describes an electrospun polyvinyl alcohol (PVA) fibrous membranes loaded with antibacterial drugs. The concentration of artemisinin (ART)/chloroquine phosphate (CQP) in PVA solution and the process parameters were investigated. Meanwhile, the physical properties and antibacterial effect, filtration performance, respiratory resistance and the surface wettability of drug membranes were tested and analyzed. The results showed that when the mass concentration of PVA was 9 wt.% and the dosage of ART/CQP was 1.5/10 mg/mL, the fibers had uniform thickness and no beads. The prepared PVA fiber membrane has good hydrophilic, filtration and antibacterial properties, and the inhibition zone to Staphylococcus aureus and Escherichia coli was 7 ± 0.3 mm and 4 ± 0.2 mm, respectively. The development of antibacterial PVA drug loaded fibrous membranes has potential value in the application of medical protective mask materials.

The paper describes the preparation of a porous bombyx mori silk fibroin (SF)/wool keratin (WK) composite scaffold with mimic structure and function for cartilage tissue engineering. A porous composite scaffold made from SF/WK in an appropriate concentration and mass ratio was prepared using a freeze-drying technique. Results showed that the composite scaffolds are water-insoluble; possess good mechanical properties, porosity above 80%, and pore size above 200 μm. Larger pore size and better connectivity of the composite scaffold than the pure SF scaffolds were contributed by the WK addition. The heat resistance and water-swelling of WK enhanced the thermal and mechanical properties of the composite scaffolds. In vitro cytotoxicity assessments showed cells with a good growth state, confirming no toxicity to the cells. The results of in vivo biocompatibility assessments exhibited that there is almost no inflammatory response in the implantation site tissue of the rats. The development of porous SF/WK composite scaffold has the potential in cartilage tissue engineering.

Background Ginsenosides accumulation responses to temperature are critical to quality formation in cold-dependent American ginseng. However, the studies on cold requirement mechanism relevant to ginsenosides have been limited in this species. Methods Two experiments were carried out: one was a multivariate linear regression analysis between the ginsenosides accumulation and the environmental conditions of American ginseng from different sites of China and the other was a synchronous determination of ginsenosides accumulation, overall DNA methylation, and relative gene expression in different tissues during different developmental stages of American ginseng after experiencing different cold exposure duration treatments. Results Results showed that the variation of the contents as well as the yields of total and individual ginsenosides Rg1, Re, and Rb1 in the roots were closely associated with environmental temperature conditions which implied that the cold environment plays a decisive role in the ginsenoside accumulation of American ginseng. Further results showed that there is a cyclically reversible dynamism between methylation and demethylation of DNA in the perennial American ginseng in response to temperature seasonality. And sufficient cold exposure duration in winter caused sufficient DNA demethylation in tender leaves in early spring and then accompanied the high expression of flowering gene PqFT in flowering stages and ginsenosides biosynthesis gene PqDDS in green berry stages successively, and finally, maximum ginsenosides accumulation occurred in the roots of American ginseng. Conclusion We, therefore, hypothesized that cold-induced DNA methylation changes might regulate relative gene expression involving both plant development and plant secondary metabolites in such cold-dependent perennial plant species.