Ningbo University of Technology

Plant secondary metabolites (SMs) are not only a useful array of natural products but also an important part of plant defense system against pathogenic attacks and environmental stresses. With remarkable biological activities, plant SMs are increasingly used as medicine ingredients and food additives for therapeutic, aromatic and culinary purposes. Various genetic, ontogenic, morphogenetic and environmental factors can influence the biosynthesis and accumulation of SMs. According to the literature reports, for example, SMs accumulation is strongly dependent on a variety of environmental factors such as light, temperature, soil water, soil fertility and salinity, and for most plants, a change in an individual factor may alter the content of SMs even if other factors remain constant. Here, we review with emphasis how each of single factors to affect the accumulation of plant secondary metabolites, and conduct a comparative analysis of relevant natural products in the stressed and unstressed plants. Expectantly, this documentary review will outline a general picture of environmental factors responsible for fluctuation in plant SMs, provide a practical way to obtain consistent quality and high quantity of bioactive compounds in vegetation, and present some suggestions for future research and development.

Abstract Hydrogen peroxide (H 2 O 2 ) has received increasing attention because it is not only a mild and environmentally friendly oxidant for organic synthesis and environmental remediation but also a promising new liquid fuel. The production of H 2 O 2 by photocatalysis is a sustainable process, since it uses water and oxygen as the source materials and solar light as the energy. Encouraging processes have been developed in the last decade for the photocatalytic production of H 2 O 2 . In this Review we summarize research progress in the development of processes for the photocatalytic production of H 2 O 2 . After a brief introduction emphasizing the superiorities of the photocatalytic generation of H 2 O 2 , the basic principles of establishing an efficient photocatalytic system for generating H 2 O 2 are discussed, highlighting the advanced photocatalysts used. This Review is concluded by a brief summary and outlook for future advances in this emerging research field.

Phenolic compounds arise from the shikimic and acetic acid (polyketide) metabolic pathways in plants. They are but one category of the many secondary metabolites implicated in plant allelopathy. Phenolic allelochemicals have been observed in both natural and managed ecosystems, where they cause a number of ecological and economic problems, such as declines in crop yield due to soil sickness, regeneration failure of natural forests, and replanting problems in orchards. Phenolic allelochemical structures and modes of action are diverse and may offer potential lead compounds for the development of future herbicides or pesticides. This article reviews allelopathic effects, analysis methods, and allelopathic mechanisms underlying the activity of plant phenolic compounds. Additionally, the currently debated topic in plant allelopathy of whether catechin and 8-hydroxyquinoline play an important role in Centaurea maculata and Centaurea diffusa invasion success is discussed. Overall, the main purpose of this review is to highlight the allelopacthic potential of phenolic compounds to provide us with methods to solve various ecology problems, especially in regard to the sustainable development of agriculture, forestry, nature resources and environment conservation.

Metal-organic frameworks (MOFs) as chemical sensors have developed rapidly in recent years. There have been many papers concerning this field and interest is still growing. The reason is that the specific merits of MOFs can be utilized to enhance sensitivity and selectivity by various energy/charge transfers occurring among different ligands, ligand, and metal centers, such as from ligands to metal centers or metal centers to ligands, as well as from MOF skeletons to guest species. This review intends to provide an update on recent progress in various applications of different MOF-based sensors on the basis of their luminescent and electrochemical responses towards small molecules, gas molecules, ions (cations and anions), pH, humidity, temperature, and biomolecules. MOF-based sensors function by utilizing different mechanisms, including luminescent responses of "turn-on" and "turn-off", as well as electrochemical responses.

Flexible pressure and strain sensors have great potential for applications in wearable and implantable devices, soft robotics and artificial skin. Compared to flexible sensors based on filler/elastomer composites, conductive hydrogels are advantageous due to their biomimetic structures and properties, as well as biocompatibility. Numerous chemical and structural designs provide unlimited opportunities to tune the properties and performance of conductive hydrogels to match various demands for practical applications. Many electronically and ionically conductive hydrogels have been developed to fabricate pressure and strain sensors with different configurations, including resistance type and capacitance type. The sensitivity, reliability and stability of hydrogel sensors are dependent on their network structures and mechanical properties. This review focuses on tough conductive hydrogels for flexible sensors. Representative strategies to prepare stretchable, strong, tough and self-healing hydrogels are briefly reviewed since these strategies are illuminating for the development of tough conductive hydrogels. Then, a general account on various conductive hydrogels is presented and discussed. Recent advances in tough conductive hydrogels with well designed network structures and their sensory performance are discussed in detail. A series of conductive hydrogel sensors and their application in wearable devices are reviewed. Some perspectives on flexible conductive hydrogel sensors and their applications are presented at the end.

In this article, a new decomposition theory, feature mode decomposition (FMD), is tailored for the feature extraction of machinery fault. The proposed FMD is essentially for the purpose of decomposing the different modes by the designed adaptive finite-impulse response (FIR) filters. Benefitting from the superiority of correlated Kurtosis, FMD takes the impulsiveness and periodicity of fault signal into consideration simultaneously. First, a designed FIR filter bank by Hanning window initialization is used to provide a direction for the decomposition. The period estimation and updating process are then used to lock the fault information. Finally, the redundant and mixing modes are removed in the process of mode selection. The superiority of the FMD is demonstrated to adaptively and accurately decompose the fault mode as well as robust to other interferences and noise using simulated and experimental data collected from bearing single and compound fault. Moreover, it has been demonstrated that FMD has superiority in feature extraction of machinery fault compared with the most popular variational mode decomposition.

Abstract Articular cartilage has poor ability to heal once damaged. Tissue engineering with scaffolds of polymer hydrogels is promising for cartilage regeneration and repair. Polymer hydrogels composed of highly hydrated crosslinked networks mimic the collagen networks of the cartilage extracellular matrix and thus are employed as inserts at cartilage defects not only to temporarily relieve the pain but also to support chondrocyte proliferation and neocartilage regeneration. The biocompatibility, biofunctionality, mechanical properties, and degradation of the polymer hydrogels are the most important parameters for hydrogel‐based cartilage tissue engineering. Degradable biopolymers with natural origin have been widely used as biomaterials for tissue engineering because of their outstanding biocompatibility, low immunological response, low cytotoxicity, and excellent capability to promote cell adhesion, proliferation, and regeneration of new tissues. This review covers several important natural proteins (collagen, gelatin, fibroin, and fibrin) and polysaccharides (chitosan, hyaluronan, alginate and agarose) widely used as hydrogels for articular cartilage tissue engineering. The mechanical properties, structures, modification, and structure–performance relationship of these hydrogels are discussed since the chemical structures and physical properties dictate the in vivo performance and applications of polymer hydrogels for articular cartilage regeneration and repair. © 2012 Society of Chemical Industry

The trifluoromethyl group plays an increasingly important role in pharmaceuticals, agrochemicals and materials. This tutorial describes recent advances in trifluoromethylation of carbon-centered radical intermediates.

Biocompatible conductive hydrogels with intrinsic flexibility, high sensitivity, linearity and outstanding reliability are highly demanded for wearable devices or implantable sensors. Here we report novel tough conductive hydrogels composed of interpenetrating polyaniline (PANI) and poly(acrylamide-co-hydroxyethyl methyl acrylate) (P(AAm-co-HEMA)) networks. Intrinsic interactions between the conductive PANI network and the flexible P(AAm-co-HEMA) endowed hydrogels with outstanding strength and toughness to cyclic loadings. The conductive hydrogels show very high sensitivity (gauge factor 11) and outstanding linear dependence of sensitivity on strain. Strain sensors based on the conductive hydrogels demonstrate reliable detection of repeated large strains and subtle vibrations, including the movements of various human joints, pulses and voiceprints. Moreover, a prototype 2D sensor array is fabricated to sense strains or pressures in the two dimensions, which is promising for electronic skin, touchpads, biosensors, human-machine interfaces, biomedical implants, wearable electronic devices and so on.

Near-infrared (NIR) activatable fluorescent probes have been considered to be the effective edge tools for the investigation of cell biology and disease diagnosis because of their outstanding advantages. Related genes involved in tumor genesis and progression regulate the overexpression of certain enzymes. Owing to the distinctive characteristics of quick reaction time and favorable pharmacokinetics, enzyme-reactive NIR optical probes have shown great potential in the diagnosis of tumorigenesis and in image-guided intraoperative surgeries with high signal-to-noise ratios. In this review, we mainly summarize the latest advancements in enzyme-reactive NIR fluorescent probes from design strategy to biomedical application. Specifically, some challenges and prospects in this field are presented at the end of the review, which will be beneficial to innovatively construct new multifunctional fluorescent probes and actively promote their clinical transformation in the future.

Abstract The T-cell surface molecule TIGIT is an immune checkpoint molecule that inhibits T-cell responses, but its roles in cancer are little understood. In this study, we evaluated the role TIGIT checkpoint plays in the development and progression of gastric cancer. We show that the percentage of CD8 T cells that are TIGIT+ was increased in gastric cancer patients compared with healthy individuals. These cells showed functional exhaustion with impaired activation, proliferation, cytokine production, and metabolism, all of which were rescued by glucose. In addition, gastric cancer tissue and cell lines expressed CD155, which bound TIGIT receptors and inactivated CD8 T cells. In a T cell–gastric cancer cell coculture system, gastric cancer cells deprived CD8 T cells of glucose and impaired CD8 T-cell effector functions; these effects were neutralized by the additional glucose or by TIGIT blockade. In gastric cancer tumor cells, CD155 silencing increased T-cell metabolism and IFNγ production, whereas CD155 overexpression inhibited T-cell metabolism and IFNγ production; this inhibition was neutralized by TIGIT blockade. Targeting CD155/TIGIT enhanced CD8 T-cell reaction and improved survival in tumor-bearing mice. Combined targeting of TIGIT and PD-1 further enhanced CD8 T-cell activation and improved survival in tumor-bearing mice. Our results suggest that gastric cancer cells inhibit CD8 T-cell metabolism through CD155/TIGIT signaling, which inhibits CD8 T-cell effector functions, resulting in hyporesponsive antitumor immunity. These findings support the candidacy of CD155/TIGIT as a potential therapeutic target in gastric cancer. Cancer Res; 77(22); 6375–88. ©2017 AACR.

Abstract Currently, it is still a significant challenge to simultaneously boost various reactions by one electrocatalyst with high activity, excellent durability, as well as low cost. Herein, hybrid trifunctional electrocatalysts are explored via a facile one‐pot strategy toward an efficient oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The catalysts are rationally designed to be composed by FeCo nanoparticles encapsuled in graphitic carbon films, Co 2 P nanoparticles, and N,P‐codoped carbon nanofiber networks. The FeCo nanoparticles and the synergistic effect from Co 2 P and FeCo nanoparticles make the dominant contributions to the ORR, OER, and HER activities, respectively. Their bifunctional activity parameter (∆ E ) for ORR and OER is low to 0.77 V, which is much smaller than those of most nonprecious metal catalysts ever reported, and comparable with state‐of‐the‐art Pt/C and RuO 2 (0.78 V). Accordingly, the as‐assembled Zn–air battery exhibits a high power density of 154 mW cm −2 with a low charge–discharge voltage gap of 0.83 V (at 10 mA cm −2 ) and excellent stability. The as‐constructed overall water‐splitting cell achieves a current density of 10 mA cm −2 (at 1.68 V), which is comparable to the best reported trifunctional catalysts.

Safety is one of the key requirements for automated vehicles and fault diagnosis is an effective technique to enhance the vehicle safety. The model-based fault diagnosis method models the fault into the system model and estimates the faults by observer. In this article, to avoid the complexity of designing observer, we investigate the problem of steering actuator fault diagnosis for automated vehicles based on the approach of model-based support vector machine (SVM) classification. The system model is utilized to generate the residual signal as the training data and the data-based algorithm of the SVM classification is employed to diagnose the fault. Due to the phenomena of data unbalance induced poor performance of the data-driven method, an undersampling procedure with the approach of linear discriminant analysis and a threshold adjustment using the algorithm of grey wolf optimizer are proposed to modify and improve the performance of classification and fault diagnosis. Various comparisons are carried out based on widely used datasets. The comparison results show that the proposed algorithm has superiority on the classification over existing methods. Experimental results and comparisons of an automated vehicle illustrate the effectiveness of the proposed algorithm on the steering actuator fault diagnosis.

Highly permeable and selective, as well as plasticization‐resistant membranes are desired as promising alternatives for cost‐ and energy‐effective CO 2 separation. Here, robust mixed‐matrix membranes based on an amino‐functionalized zeolitic imidazolate framework ZIF‐7 (ZIF‐7‐NH 2 ) and crosslinked poly(ethylene oxide) rubbery polymer are successfully fabricated with filler loadings up to 36 wt%. The ZIF‐7‐NH 2 materials synthesized from in situ substitution of 2‐aminobenzimidazole into the ZIF‐7 structure exhibit enlarged aperture size compared with monoligand ZIF‐7. The intrinsic separation ability for CO 2 /CH 4 on ZIF‐7‐NH 2 is remarkably enhanced as a result of improved CO 2 uptake capacity and diffusion selectivity. The incorporation of ZIF‐7‐NH 2 fillers simultaneously makes the neat polymer more permeable and more selective, surpassing the state‐of‐the‐art 2008 Robeson upper bound. The chelating effect between metal (zinc) nodes of fillers and ester groups of a polymer provides good bonding, enhancing the mechanical strength and plasticization resistance of the neat polymer membrane. The developed novel ZIF‐7 structure with amino‐function and the resulting nanocomposite membranes are very attractive for applications like natural‐gas sweetening or biogas purification.

As a generalization of intuitionistic fuzzy set, the Pythagorean fuzzy set is interesting and very useful in modeling uncertain information in real-world decision-making problems. In this paper, we develop a new method for Pythagorean fuzzy multiple-criteria decision-making (MCDM) problems with aggregation operators and distance measures. First, we present the Pythagorean fuzzy ordered weighted averaging weighted average distance (PFOWAWAD) operator. The main advantage of the PFOWAWAD operator is that it uses distance measures in a unified framework between the ordered weighted averaging (OWA) operator and weighted average (WA) that considers the degree of importance of each concept in the aggregation. Some of its main properties and special cases are studied. Then, based on the proposed operator, a hybrid TOPSIS method, called PFOWAWAD-TOPSIS is introduced for Pythagorean fuzzy MCDM problem. Finally, a numerical example is provided to illustrate the practicality and feasibility of the developed method.

BACKGROUND: Hypertension and the triglyceride and glucose index both have been associated with insulin resistance; however, the longitudinal association remains unclear. This study was designed to investigate the longitudinal association between the triglyceride and glucose index and incident hypertension among the Chinese population. METHODS: We studied 4686 subjects (3177 males and 1509 females) and followed up for 9 years. The subjects were divided into four groups based on the triglyceride and glucose index. Univariate and multivariate Cox regression models were used to analyse the risk factors of hypertension. RESULTS: After 9 years of follow-up, 2047 subjects developed hypertension. The overall 9-year cumulative incidence of hypertension was 43.7%, ranging from 28.5% in quartile 1 to 36.9% in quartile 2, 49.2% in quartile 3 and 59.8% in quartile 4 (p for trend < 0.001). Cox regression analyses indicated that higher triglyceride and glucose index was associated with an increased risk of subsequent incident hypertension. CONCLUSION: The triglyceride and glucose index can predict the incident hypertension among the Chinese population.

New fluorochromic materials that reversibly change their emission properties in response to their environment are of interest for the development of sensors and light-emitting materials. A new design of Eu-containing polymer hydrogels showing fast self-healing and tunable fluorochromic properties in response to five different stimuli, including pH, temperature, metal ions, sonication, and force, is reported. The polymer hydrogels are fabricated using Eu-iminodiacetate (IDA) coordination in a hydrophilic poly(N,N-dimethylacrylamide) matrix. Dynamic metal-ligand coordination allows reversible formation and disruption of hydrogel networks under various stimuli which makes hydrogels self-healable and injectable. Such hydrogels show interesting switchable ON/OFF luminescence along with the sol-gel transition through the reversible formation and dissociation of Eu-IDA complexes upon various stimuli. It is demonstrated that Eu-containing hydrogels display fast and reversible mechanochromic response as well in hydrogels having interpenetrating polymer network. Those multistimuli responsive fluorochromic hydrogels illustrate a new pathway to make smart optical materials, particularly for biological sensors where multistimuli response is required.

ZnO nanocrystalline materials with different crystallite and particle sizes were synthesized by the solvothermal approach. The structure and optical properties were investigated using powder X-ray diffraction (XRD), nitrogen adsorption isotherms, UV–vis diffuse reflectance spectroscopy (DRS), transmission and scanning electron microscopy (TEM), and room temperature photoluminescence. It was found that the crystallite and particle sizes of ZnO nanocrystalline could be controlled by changing the solvent during the solvothermal synthesis. The photocatalytic activity was evaluated by the degradation of dye Rhodamine B (RhB) under visible irradiation. The individual effect of crystallite size and particle size on the photocatalytic activity of ZnO was studied using the ZnO nanocrystallites prepared in this work.

Bioderived flame retardants represent one class of the most promising sustainable additives for creating flame retardant polylactic acid (PLA) because of their marginal impact on the biodegradability of PLA. Ammonium polyphosphate (APP) has demonstrated high flame-retardant effectiveness in PLA but its flame-retardant efficiency remains unsatisfactory even if after modifications. Herein, we report the facile fabrication of core–shell bioderived flame retardants by using APP as the core, and the chitosan (CS)/alginate (AA) bilayer as the shell through self-assembly in aqueous solution. The resultant core–shell flame retardant, APP@CS@AA-nBL (where 'BL' is a CS&amp;AA bilayer and 'n' denotes 1–3 BL), can endow PLA with improved flame retardancy without negatively affecting the thermal properties. The PLA containing 10 wt % APP@CS@AA-3BL shows the highest LOI value (30.6%) and achieves a UL94 V-0 rating in the vertical burning test. Meanwhile, the cone calorimetry results demonstrate that the peak of the heat release rate and total heat release are respectively decreased by 23% and 11% relative to the PLA bulk. Such enhanced flame retardancy is mainly due to the excellent char-forming capability of APP@CS@AA. Moreover, the inclusion of 10 wt % APP@CS@AA-3BL gives rise to ∼23% increase in the impact strength of PLA possibly because of their interfacial hydrogen-bonding interactions. This work provides a facile and green strategy for preparing highly effective bioderived flame retardants for PLA and thus is expected to expand the practical applications in industry.

Direct decarboxylative radical allylation of aliphatic carboxylic acids is described. With K2S2O8 as the oxidant and AgNO3 as the catalyst, the reactions of aliphatic carboxylic acids with allyl sulfones in aqueous CH3CN solution gave the corresponding alkenes in satisfactory yields under mild conditions. This site-specific allylation method is applicable to all primary, secondary, and tertiary alkyl acids and exhibits wide functional group compatibility.