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(Z)-7-Aryl-5-acyldibenzo[e,g][1,4]diazocin-6(5H)-one, a unique saddle-shaped bridged biaryl containing synchronized aryl-aryl and N-aryl stereogenic axes, was constructed for the first time in good...

RationalePulmonary fibrosis is a devastating lung disease with few therapeutic options. Chitinase 1 (CHIT1), an 18 glycosyl hydrolase family member, contributes to the pathogenesis of pulmonary fibrosis through regulation of Transforming Growth Factor (TGF)-β signaling and effector function. Therefore, CHIT1 is a potential therapeutic target of pulmonary fibrosis.ObjectivesThis study aimed to identify and characterize a druggable CHIT1 inhibitor with strong antifibrotic activity and minimal toxicity for therapeutic application to pulmonary fibrosis.MethodsExtensive screening of small molecule libraries identified the aminoglycoside antibiotic Kasugamycin as a potent CHIT1 inhibitor.Measurements and Main ResultsElevated levels of CHIT1 were detected in the lungs of patients with pulmonary fibrosis. In vivo bleomycin- and TGF-β-stimulated murine models of pulmonary fibrosis, Kasugamycin showed impressive anti-fibrotic effects in both preventive and therapeutic conditions. In vitro studies also demonstrated that Kasugamycin inhibits fibrotic macrophage activation, fibroblast proliferation and myofibroblast transformation. Null mutation of transforming growth factor beta associated protein 1 (TGFBRAP1), a recently identified CHIT1 interacting signaling molecule, phenocopied antifibrotic effects of Kasugamycin in in vivo lungs and in vitro fibroblasts responses. Kasugamycin inhibits physical association between CHIT1 and TGFBRAP1, suggesting that antifibrotic effect of Kasugamycin is mediated through regulation of TGFBRAP1, at least in part.ConclusionsThese studies demonstrate that Kasugamycin is a novel CHIT1 inhibitor with strong antifibrotic effect that can be further developed as an effective and safe therapeutic drug for pulmonary fibrosis.

Rhynchines A-E (1-5), five new indole alkaloids with an unprecedented skeleton, were isolated from Uncaria rhynchophylla. The new skeleton was characterized by an indole moiety and a 2-oxa-8-azatricyclo[6,5,01,5,01,8]tridecane core, forming a unique 6/5/7/5/5 ring system. Their structures were determined by nuclear magnetic resonance, high-resolution electrospray ionization mass spectrometry, infrared spectroscopy, and calculated electronic circular dichroism (ECD) and were confirmed by X-ray crystallography. Interestingly, 1 and 2 showed strong inhibitory activities against the Cav3.1 calcium channel with IC50 values of 6.86 and 10.41 μM.

Reported herein is a regioselective difluoromethane sulfonylation or triflylation of resorufin derivatives, which allows easy access to 2-difluoromethane sulfonylated or triflylated resorufin derivatives in good yields. The installation of a difluoromethane sulfonyl group significantly increases the solubility of the chromophore and expands its Stokes shift. A difluoromethane sulfonylated resorufin-based fluorogenic probe proved to be able to image enzyme activity in live cells with a stronger fluorescence signal compared with its resorufin counterpart.

γ-Aminobutyric acid (GABA) is a non-protein amino acid involved in regulating various environmental adaption in plants. Twenty-six-day-old creeping bentgrass plants were treated with or without GABA (0.5 mM) and then exposed to heat stress (35/30 °C, day/night) for 25 days. Results showed that exogenous GABA application significantly increased endogenous GABA accumulation and alleviated heat-caused growth inhibition and water loss during heat stress. GABA-treated creeping bentgrass maintained significantly lower carbonyl content, malondialdehyde content, and electrolyte leakage, but exhibited higher total antioxidant capacity and antioxidant enzyme activities (SOD, CAT, POD, APX, and DR) than untreated plants under heat stress. Heat stress significantly decreased chlorophyll content, stomatal conductance, transpiration rate, net photosynthesis, and water use efficiency. However, GABA application effectively alleviated these heat-induced negative effects in creeping bentgrass. In addition, exogenous GABA further increased the expression of heat-induced HSPs (HSP12, HSP17.8, HSP26.7, HSP70, HSP82, HSP90.1-A1, HSP90.1-B1, and HSP90-5) and HSFs (HSFA-2c, HSFA-2d, HSFA-6a, HSFB-2b, and HSFC-2b) and also further increased the abundance of HSP70, HSP90-1, and HSP101 in leaves of creeping bentgrass under heat stress. These results indicated that GABA alleviated heat-induced oxidative damage and chlorophyll loss through enhancing antioxidant capacity. GABA-treated creeping bentgrass maintained higher photosynthesis in leaves contributing to higher accumulation of water soluble carbohydrates for osmotic balance and energy supply under heat stress. GABA-regulated thermotolerance could be involved in upregulating HSF pathways in creeping bentgrass.

S-adenosylmethionine decarboxylase (SAMDC) mediates the biosynthesis of polyamines (PAs) and plays a positive role in plants’ response to adversity stress tolerance. In this study, we isolated a SAMDC gene from white clover, which is located in mitochondria. It was strongly induced when white clover exposed to drought (15% PEG6000), salinity (200 mM NaCl), 20 μM spermidine, 100 μM abscisic acid, and 10 mM H2O2, especially in leaves. The INVSc1 yeast introduced with TrSAMDC1 had tolerance to drought, salt, and oxidative stress. Overexpression of TrSAMDC1 in Arabidopsis showed higher fresh weight and dry weight under drought and salt treatment and without growth inhibition under normal conditions. Leaf senescence induced by drought and saline was further delayed in transgenic plants, regardless of cultivation in 1/2 MS medium and soil. During drought and salt stress, transgenic plants exhibited a significant increase in relative water content, maximum photosynthesis efficiency (Fv/Fm), performance index on the absorption basis (PIABS), activities of antioxidant protective enzymes such as SOD, POD, CAT, and APX, and a significant decrease in accumulation of MDA and H2O2 as compared to the WT. The concentrations of total PAs, putrescine, spermidine, and spermidine in transgenic lines were higher in transgenic plants than in WT under normal and drought conditions. These results suggested that TrSAMDC1 could effectively mitigate abiotic stresses without the expense of production and be a potential candidate gene for improving the drought and salt resistance of crops.

N-1-Alkyl-2-unsubstituted benzimidazoles were directly synthesized by intermolecular coupling of formimidamides with benzylamines; the syntheses were catalyzed by Pd(OAc)2 in one pot, giving rise to moderate to good yields. Aromatic formamidines with various substituents as starting materials could be readily prepared from the reactions of the corresponding anilines and N,N-dimethylformamide dimethyl acetal in high yields.

We report a two-step rapid and efficient synthesis of β-amino-α,β-unsaturated esters. Microwave-assisted synthesis was used throughout the process. Seventeen β-amino-α,β-unsaturated esters were pro...

Self-healing is a process in which the non-equilibrium state caused by mechanical damage gradually evolves toward the equilibrium state. However, tracking this process is highly challenging. Here, we copolymerize a fluorophore (TC1) with a strong aggregation-caused quenching (ACQ) effect in a self-healing elastomer with a dynamic hydrogen-bonded network. We find that TC1 is highly sensitive to the local chain packing environment and thus can detect the subtle microstructural change induced by mechanical damage and self-healing. Confocal laser scanning microscopy reveals that the fluorescence intensity evidently increases around the fracture surface and scratch, indicating that the mechanical damage induces a slight decrease of chain packing efficiency. Upon annealing the fracture surface for a certain period of time before healing, both the fluorescence intensity and healing efficiency decrease with time, and interestingly there is a linear relationship between them. If the scratch is allowed to heal at room temperature, the fluorescence intensity around the scratch also decreases linearly with time until the contrast between the scratch and normal surface becomes hardly distinguishable. Therefore, this work provides a novel way to study the self-healing process of dynamically crosslinked materials.

In spite of considerable progress in self-healing polymers, detecting the healing kinetics and its underlying molecular mechanism is still in the early development stage. Herein, we design a self-healing ionomer by grafting AIEgens (PyTPE) as sticky groups onto a bromo-matrix (PBMB). The ionomer shows good mechanical properties (15 MPa, 300%) and crack healing efficiency at room temperature. Interestingly, the grafted AIEgen stickers enable us to quantify the healing kinetics and its underlying microscopic structural change through the evolution of fluorescence intensity induced by the AIE effect. In addition, a 2D correlation analysis indicates that the decoupled ionic moieties move first to recombine again during the healing process, finally leading to the reconstruction of a transient network and macro-healing. Therefore, this work offers a fluorescence-based method to study the microscopic self-healing mechanism of ionomers during damage and healing processes.

Cunlanceloic acid A (1), a symmetric terpenoid peroxide bearing an unprecedented dimeric labdane backbone linked through C-16/C-16′ bonds, and cunlanceloic acids B–D (2–4), three asymmetric diterpenoid dimers with a new carbon skeleton linked through C12/C-13′ and C-15/C-16′ bonds between two labdane units, were isolated from the cones of Cunninghamia lanceolata. Their structures including absolute configurations were determined by extensive NMR spectroscopy, X-ray diffraction analysis, and chemical transformations. Compound 1 exhibited potent AChE inhibitory activity with an IC50 value of 6.14 ± 0.66 μM and compounds 2 and 3 showed remarkable cytotoxic activities against A-549 and SMMC-7721 cell lines with IC50 values of 5.90–9.21 μM.

We report conversion of esters to thioesters via selective C-O bond cleavage/weak C-S bond formation under transition-metal-free conditions. The method is notable for a general and practical transition-metal-free system, broad substrate scope and excellent functional group tolerance. The strategy was successfully deployed in late-stage thioesterification, site-selective cross-coupling/thioesterification/decarbonylation and easy-to-handle gram scale thioesterification. Selectivity and computational studies were performed to gain insight into the formation of weak C-S bonds by C-O bond cleavage, which contrasts with the traditional trend of nucleophilic additions to carboxylic acid derivatives.

We report a general and practical palladium-catalyzed intramolecular decarbonylative coupling of thioesters via C–S bond cleavage, decarbonylation and C–S bond reformation. This robust approach shows excellent functional group tolerance and broad substrate scope using a commercially available, cheap, and practical Pd(OAc)2 catalyst and phosphine ligands. This strategy operates under base-free conditions. The catalytic system represents the simplest method for intramolecular decarbonylation of thioesters by palladium catalysis reported to date. This versatile protocol is readily performed on a gram scale and applied in late-stage drug derivatization.

The reaction of the redox-active tetrathiafulvalene ligand and lanthanide ions is an important approach to prepare photo-electro-magnetic multifunctional metal–organic framework materials. A series of isostructural lanthanide metal–organic frameworks (Ln-MOFs) based on the in situ generated tetrathiafulvalene dicarboxylate (TTF-DC) ligand, {[Ln4(TTF-DC)6(DMF)4(H2O)2]·4DMF}n (Ln = Gd (1-Gd), Tb (1-Tb), Dy (1-Dy) and Er (1-Er)), was synthesized and characterized. These Ln-MOFs display tunable redox-active properties and semiconductor performance, and their electronic conductivities have been significantly improved after oxidation. All MOFs except 2-Tb exhibit slow magnetic relaxation under an applied dc field. 1-Dy and 2-Dy show field-induced single-molecule magnet (SMM) behaviour with energy barriers (Ueff) of 30.77 K (τ0 = 5.23 × 10−8) and 26.41 K (1.04 × 10−8 s), respectively.

The low O2− diffusion rate in the electro-deoxidation of titanium containing compounds by either the OS process or the FFC process leads to a low reaction speed and a low current efficiency. In this study, Ca3Ti2O7 was used as a precursor to improve the reduction speed of titanium. Because of the greater number of “diffusion channels” created in cathode as Ca2+ liberates from Ca3Ti2O7 precursor in the electro-deoxidation process, the O2− diffusion rate was improved significantly by using Ca3Ti2O7 instead of CaTiO3 as precursor. Parallel constant voltage electrolysis (3.2 V) confirms that Ca3Ti2O7 and CaTiO3 are reduced simultaneously because of their similar crystal structures. However, the reduction area of Ca3Ti2O7 spreads much faster than that of CaTiO3, indicating a difference in the O2− diffusion rate. Constant voltage cyclic voltammetry (CV) and theoretical analysis of the crystal structure were also conducted to compare the differences between Ca3Ti2O7 and CaTiO3. The results indicate that using a precursor with a greater number of soluble cations, titanium reduction speed can be greatly improved in the electro-deoxidation process. Finally, a new electrolysis method for converting and recycling excess CaO from the Ca3Ti2O7 precursor was proposed.

Background Chitosan (CTS), a natural polysaccharide, exhibits multiple functions of stress adaptation regulation in plants. However, effects and mechanism of CTS on alleviating salt stress damage are still not fully understood. Objectives of this study were to investigate the function of CTS on improving salt tolerance associated with metabolic balance, polyamine (PAs) accumulation, and Na+ transport in creeping bentgrass (Agrostis stolonifera). Results CTS pretreatment significantly alleviated declines in relative water content, photosynthesis, photochemical efficiency, and water use efficiency in leaves under salt stress. Exogenous CTS increased endogenous PAs accumulation, antioxidant enzyme (SOD, POD, and CAT) activities, and sucrose accumulation and metabolism through the activation of sucrose synthase and pyruvate kinase activities, and inhibition of invertase activity. The CTS also improved total amino acids, glutamic acid, and γ-aminobutyric acid (GABA) accumulation. In addition, CTS-pretreated plants exhibited significantly higher Na+ content in roots and lower Na+ accumulation in leaves then untreated plants in response to salt stress. However, CTS had no significant effects on K+/Na+ ratio. Importantly, CTS enhanced salt overly sensitive (SOS) pathways and also up-regulated the expression of AsHKT1 and genes (AsNHX4, AsNHX5, and AsNHX6) encoding Na+/H+ exchangers under salt stress. Conclusions The application of CTS increased antioxidant enzyme activities, thereby reducing oxidative damage to roots and leaves. CTS-induced increases in sucrose and GABA accumulation and metabolism played important roles in osmotic adjustment and energy metabolism during salt stress. The CTS also enhanced SOS pathway associated with Na+ excretion from cytosol into rhizosphere, increased AsHKT1 expression inhibiting Na+ transport to the photosynthetic tissues, and also up-regulated the expression of AsNHX4, AsNHX5, and AsNHX6 promoting the capacity of Na+ compartmentalization in roots and leaves under salt stress. In addition, CTS-induced PAs accumulation could be an important regulatory mechanism contributing to enhanced salt tolerance. These findings reveal new functions of CTS on regulating Na+ transport, enhancing sugars and amino acids metabolism for osmotic adjustment and energy supply, and increasing PAs accumulation when creeping bentgrass responds to salt stress.

A palladium-catalyzed domino process for the quick assembly of tricyclic-fused heterocycles starting from aryl iodides and functionalized isocyanides containing a disubstituted terminal alkene has been developed. The process is triggered by intermolecular isocyanide insertion, followed by Heck-type carbopalladation of the intramolecular alkene moiety and subsequent C(sp2)-H activation. Moreover, an asymmetric version of this reaction could also be realized in good yield with moderate enantioselectivity after preliminary exploration of chiral ligands.

Acrylonitrile butadiene styrene (ABS), as a main component of plastics of waste electrical and electronic equipment (WEEE), shows high potential for recycling, which is restricted by the absence of an efficient separation method. Herein, a novel surface treatment method, microwave treatment combined with a wetting agent, was proposed to selectively change the hydrophilicity of the mixed waste plastics, which efficiently separated ABS from the WEEE plastics by flotation. The results of this approach provided the following optimal conditions, i.e., microwave power 700 W, microwave irradiation time 3 min, concentration of wetting agent carboxymethylcellulose sodium (CMC) 25 mg/L, treatment time with CMC 5 min, stirring rate 1800 rpm, frother concentration 40 mg/L, and flotation time 4 min. Under these optimal conditions, the recovery and the purity of ABS reached 97.70% and 99.86%, respectively. The mechanism of the surface treatment was examined by means of contact angle, Fourier transform infrared spectroscopy (FT-IR), and adsorption kinetics. The results showed that the selective wetting mechanism can be attributed to the physisorption of CMC on the surface of plastics. In conclusion, this surface treatment method is expected to provide technological insights for the separation and recovery of waste ABS from WEEE plastics.

Polyethylene terephthalate (PET), as the largest synthetic polymer with an annual output of more than 90 million tons, has found widespread applications in our daily life and industry, especially its fiber accounts for about 90% of all synthetic fibers. However, PET is highly flammable and melt-dripping during burning, which causes serious casualties and property loss in case of fire. Although many phosphorus-based flame-retardant PETs are already commercially available, their flame retardancy is usually achieved by promoting the melt dripping of PET. The issue on flame retardation of PET without melt dripping was a big challenge both in the academia and industry, and has not been addressed for a long time because the anti-dripping behavior conflicts with the “dripping-promotion” flame-retardant mechanism of phosphorus-containing PET. Therefore, how to flame-retard PET without melt dripping has become an urgent difficult problem needed to solve. The key to designing flame-retardant PET with anti-dripping performance is to increase both the melt viscosity and char formation ability during burning. Herein, we reviewed our original works about a series of flame-retardant and anti-dripping PET copolyesters designed and synthesized via chemically incorporated functional monomers into the PET chains based on “physical interaction”, “high-temperature chemical self-crosslinking” and “high-temperature rearrangement”. Those monomers exhibit high polymerization activity with PET monomers, and those special functional groups do not affect the polymerization or processing process. Once at a higher temperature or during burning, under the actions of “ionic aggregation”, “hydrogen bond”, “chemical self-crosslinking” and “high-temperature rearrangement”, the melt viscosity and melt strength of those PET-based copolyesters would be greatly increased, upgrading excellent anti- or non-dripping performance. What is more, the dense cyclic aromatic structures, enabled by these functional groups, can further evolve into stable intumescent char layers on the surface of copolyesters, and inhibit the heat or oxygen transfer. Thus, the copolyesters exhibit good flame retardancy at the same time. In detail, the physical crosslinking networks, formed by thermally-reversible ionic aggregation, can limit the movement of molecular chains to some extent, but such effects are not enough to make corresponding copolyesters achieve non-dripping performance during the vertical burning test (UL-94). Compared with physical crosslinking, irreversible chemical crosslinking networks are more stable and stronger. Based on this idea, we have proposed a series of novel “intelligent chemical self-crosslinking” copolyesters containing crosslinkable phenylacetylene, phenylacetylene-phenylimide, phenylmaleimide, and aromatic schiff base or azobenzene groups. Those copolyesters can rapidly crosslink during burning or at the temperature higher than polymerization/processing to form stable aromatic cross-linked networks, resulting in excellent flame retardancy and non-dripping properties. In addition, the special aryl ether, bisphenol F and o-hydroxy phenylimide groups can also be used to improve the flame retardancy and anti-dripping of copolyesters via the rearrangement reactions and charring promotion at high temperatures. Among all the above, the self-crosslinkable or rearrangeable PET copolyesters exhibited higher flame-retardant efficiency, which can attain the non-dripping standard at a lower amount of third monomers. Without the use of traditional flame retardant elements such as halogen, these novel mechanisms and approaches have not only opened up a way of high temperature carbonization for the flame-retardant and anti-dripping polyester, but also provided new strategies for the green development of flame-retardant technology. Although the understanding of the design and synthesis of flame-retardant and anti-dripping PET-based copolyesters has been deepened with some breakthroughs in recent years, we still have faced the unavoidable challenges of reducing monomer contents, decreasing cost, optimizing mechanical properties, improving crystallinity and keeping spinnability in the process of practical application and industrialization of these copolyesters in the future. Actually, we have designed some more efficient and cheaper self-crosslinkable monomers recently. The much lower content of monomers can endow corresponding copolyesters with excellent comprehensive performances such as flame retardance, non-dripping, crystallization, spinnability, dyeability and mechanical properties. These state-of-art results will be presented in the near future.

Supercapacitors with good electrochemical performance and flexibility are in great demand. In this paper, the concept of preparing 3D porous carbon monoliths via direct calcination of melamine sponge is presented. This preparation method is simple and has good control of the structure. Porous carbon composite nickel-manganese oxides can be obtained by hydrothermal method followed with calcination. The electrochemical performances were tested and porous carbon monoliths with NiMn oxides exhibited a specific capacitance of 870 F/g in 1 mol/L KOH at a charge/discharge current density of 0.5 A/g and a capacity retention of 89.9% after 5000 times charge and discharge

Heat stress decreases crop growth and yield worldwide. Spermidine (Spd) is a small aliphatic amine and acts as a ubiquitous regulator for plant growth, development and stress tolerance. Objectives of this study were to determine effects of exogenous Spd on changes in endogenous polyamine (PA) and γ-aminobutyric acid (GABA) metabolism, oxidative damage, senescence and heat shock protein (HSP) expression in white clover subjected to heat stress. Physiological and molecular methods, including colorimetric assay, high performance liquid chromatography and qRT-PCR, were applied. Results showed that exogenous Spd significantly alleviated heat-induced stress damage. Application of Spd not only increased endogenous putrescine, Spd, spermine and total PA accumulation, but also accelerated PA oxidation and improved glutamic acid decarboxylase activity, leading to GABA accumulation in leaves under heat stress. The Spd-pretreated white clover maintained a significantly higher chlorophyll (Chl) content than untreated plants under heat stress, which could be related to the roles of Spd in up-regulating genes encoding Chl synthesis (PBGD and Mg-CHT) and maintaining reduced Chl degradation (PaO and CHLASE) during heat stress. In addition, Spd up-regulated HSP70, HSP70B and HSP70-5 expression, which might function in stabilizing denatured proteins and helping proteins to folding correctly in white clover under high temperature stress. In summary, exogenous Spd treatment improves the heat tolerance of white clover by altering endogenous PA and GABA content and metabolism, enhancing the antioxidant system and HSP expression and slowing leaf senescence related to an increase in Chl biosynthesis and a decrease in Chl degradation during heat stress.

Small molecules, including H2O2 and Ca, mediate stress signaling and drought tolerance in plants. The objective of this study was to determine whether improvement in drought tolerance by H2O2 and Ca were associated with the regulation of transcription factors and stress-protective genes in perennial grass species. Plants of creeping bentgrass (Agrostis stolonifera) were sprayed with water (control), H2O2 (9 mm), or CaCl2 (10 mm) and exposed to drought stress for 20 days in controlled-environment growth chambers. Foliar application of H2O2 or Ca led to significant improvement in drought tolerance of creeping bentgrass, as demonstrated by greater turf quality, leaf relative water content, chlorophyll content, photochemical efficiency, and cell membrane stability, as compared with the untreated control. The application of H2O2 and Ca resulted in significant up-regulation of genes in Ca signaling transduction pathways [Ca-dependent kinase 26 (CDPK26), mitogen-activated protein kinase 1 (MAPK1), and 14-3-3] and transcript factors (WRKY75 and MYB13). For genes encoding antioxidant enzymes, H2O2 mainly enhanced superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and dehydroascorbate reductase (DHAR) expression, while Ca primarily improved transcript levels of SOD, monodehydroascorbate reductase (MDHAR), and GR. In addition, heat shock protein 70 (HSP70), metallothionein 1 (MT1), and glutamine synthetase 2 (GS2) were also markedly up-regulated by H2O2 and Ca under drought stress. However, the transcript level of lipoxygenase 3 (LOX3) was significantly down-regulated by H2O2 and Ca under well-watered and drought conditions. These results imply that H2O2 and Ca commonly or differentially regulate genes expression in association with drought tolerance through activating Ca signaling pathway and regulating transcription factors and stress-protective genes expression, leading to the alleviation of lipid peroxidation, maintenance of correct protein folding and translocation, and enhancement of nitrogen metabolism under a prolonged period of drought stress in creeping bentgrass.

Spermine (Spm) regulates water balance involved in water channel proteins, aquaporins (AQPs), in plants. An increase in endogenous Spm content via exogenous Spm application significantly improved cell membrane stability, photosynthesis, osmotic adjustment (OA) and water use efficiency (WUE) contributing to enhanced tolerance to water stress in white clover. Spm upregulated TrTIP2-1, TrTIP2-2 and TrPIP2-7 expressions and also increased the abundance of TIP2 and PIP2-7 proteins in white clover under water stress. Spm quickly activated intracellular Ca2+ signaling and Spm-induced TrTIP2-2 and TrPIP2-7 expressions could be blocked by Ca2+ channel blockers and the inhibitor of Ca2+-dependent protein kinase in leaves of white clover. TrSAMS in relation to Spm biosynthesis was first cloned from white clover and the TrSAMS was located in the nucleus. Transgenic Arabidopsis overexpressing the TrSAMS had significantly higher endogenous Spm content and improved cell membrane stability, photosynthesis, OA, WUE and transcript levels of AtSIP1-1, AtSIP1-2, AtTIP2-1, AtTIP2-2, AtPIP1-2, AtPIP2-1 and AtNIP2-1 than wild type in response to water stress. Current findings indicate that Spm regulates water balance via an enhancement in OA, WUE and water transport related to Ca2+-dependent AQP expression in plants under water stress.

The carbide precipitation behavior and mechanical properties of advanced high strength steel deformed at different temperatures are investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) equipped with an energy dispersing spectroscopy (EDS), and tensile tests. The medium Mn steel was subjected to controlled deformation up to 70% at 750 °C, 850 °C, 950 °C, and 1050 °C, and then quenched with water to room temperature, followed by intercritical annealing at 630 °C for 10 min. In comparison with the undeformed and quenched specimen, it can be concluded that acicular cementite precipitates during the quenching and cooling process, while granular NbC is the deformation induced precipitate and grows during the following annealing process. As the deformation temperature increases from 750 °C to 1050 °C, the product of strength and elongation increases at first and then decreases. The smallest average size of second phase particles (20 nm) and the best mechanical properties (32.5 GPa.%) can be obtained at the deformation temperature of 950 °C.

Thiocyanate (SCN−) is frequently detected in the environmental matrix due to various industrial activities such as the coking wastewater and gold mining operations, thus posing a potential threat to living organisms. In the present study, we conducted a hydroponic experiment to investigate the effects of ammonium (NH4+) and nitrate (NO3−) fertilization on uptake kinetics of SCN− by rice seedlings. Inhibition rate (IR) of relative growth was used as a response endpoint to quantify the adverse effect of SCN− exposure to rice seedlings. Uptake kinetics of SCN− by rice seedlings was estimated by Michaelis–Menten equation using MATLAB 2018b. The results showed that the IR values of SCN-treated young seedlings fed with NO3− at 57.4 mg/L (30%) were higher than that at 15.24 mg NH4+/L (30%). However, the IR value of SCN-treated seedlings fed with NH4+ at 35.56 (70%) and 50.8 mg/L (100%) were higher than those of 122.43 (70%) and 174.9 mg NO3−/L (100%). A linear uptake mode for SCN− uptake was observed in the N starvation treatment, whereas exponential curves for SCN− uptake were observed in other N fertilization treatments. The calculated Michaelis–Menten kinetics (i.e., Vmax and Km) for SCN− uptake by rice seedlings fed with NO3− were higher than those of NH4+ addition. In conclusion, NH4+ fertilization resulted in more negative impact on the uptake of SCN− by rice seedlings than NO3− treatments, thus mitigating the phytotoxicity of SCN− to rice seedlings.

Huperserratines A (1) and B (2), two Lycopodium alkaloids with an unprecedented 5-aza-bicyclo[10.4.0]hexadecane skeleton and an oxime function, were isolated from Huperzia serrata. Their structures including absolute configurations were determined by extensive NMR spectroscopic and X-ray diffraction analysis. Compounds 1 and 2 were the first examples of macrocyclic Lycopodium alkaloids with an aza-12-membered ring. A plausible biogenetic pathway of these compounds was also proposed. Compound 1 exhibited moderate anti-HIV-1 activity with an EC50 of 52.91 μg/mL and a therapy index greater than 3.78.

Objective: To observe the effect of moxibustion on the mRNA and protein expressions of heat-shock protein 70 (HSP70) in gastric cancer-bearing rats. Methods: A total of 40 healthy Sprague-Dawley (SD) rats were adaptively fed for one week. The gastric cancer model was prepared by Walker-256 cancer tissue transplantation. After 7 d, 10 rats were randomly selected to verify the successful modeling, and the remaining 30 rats were divided into a model group, a moxibustion group and an infrared group by the random number table method, with 10 rats in each group. After enrollment, the moxibustion group received suspended moxibustion at Zhongwan (CV 12), Guanyuan (CV 4) and bilateral Zusanli (ST 36), (the first group of acupoints) on the 1st day, and suspended moxibustion at bilateral Pishu (BL 20) and Weishu (BL 21), (the second group of acupoints) on the 2nd day, 20 min each time, once a day. Moxibustion was alternately performed every other day at the two groups of acupoints for 21 d. From the day of enrollment, rats in the infrared group were irradiated with the infrared radiation at the stomach area on the 1st day, and at the T12-T13 interspinous region on the 2nd day, 20 min each time, once a day, and the two locations were alternately irradiated every other day for 21 d. During the treatment, rats in the model group were intervened by grasping and fixation without treatment. At the end of the treatment, blood was collected from the inner eye orbit, and the HSP70 expression in peripheral blood was determined by enzyme linked immunosorbent assay (ELISA). Rats were sacrificed, the tumor volume and growth inhibition rate were measured. The position and changes of HSP70 in gastric cancer were observed by streptavidin-perosidase (SP); HSP70 protein expression was determined by ELISA; HSP70 mRNA expression in cancer tissues was determined by reverse transcription-polymerase chain reaction (RT-PCR) assay. Results: In comparison of the model group, the volume growth of the gastric cancer in the moxibustion group was significantly restricted (P

In this study, we reported a facile two-step reduction method to prepare a high-quality graphene with intact structure. Hydroxyl group is acquired by utilizing LiAlH4 to reduce the oxygen-containing functional groups in GO. Then it is further reduced by ethanethiol/aluminum trichloride (Et-SH/AlCl3) to obtain graphene. The results of Infrared and XPS showed that the prepared graphene material (rGO2) has been reduced completely and had structural integrity. Besides, the conductivity of rGO2 obtained can reach 2.632 * 103 S m−1, which is higher than that obtained by general chemical reduction method and high temperature reduction method. Investigated as a potential material for supercapacitors, the as-prepared graphene reveals excellent electrochemical properties, including good rate capability and cycling stability, which mainly benefits from its intact structural characteristics.

Urolithin A (UroA) is a first-in-class natural compound derived from the gut microbiota-derived metabolites of ellagitannins. This research for the first time evaluates the mechanisms of UroA inhibiting advanced glycation end-product (AGE) formation by fluorescence spectroscopy, molecular docking, liquid chromatography (LC) and LC-Oribitrap tandem mass spectrometry. The results indicated that UroA exhibited a good suppression effect on the formation of AGEs in human serum albumin (HSA)–fructose and HSA–methylglyoxal (MGO) systems. Further mechanism analysis revealed that UroA alleviated AGE formation by changing the conformational structure of HSA, trapping reactive MGO to form mono-MGO–UroA complexes, promoting the exposure of chromophores to a more hydrophobic micro-environment, and forming stable UroA–HSA complexes. UroA bound with HSA in an equimolar manner, the binding was an exothermic spontaneous process, subdomain IIIA was the preferred binding pocket, and hydrogen bonding, hydrophobic interactions and van der Waals forces were the major interaction forces. The number of glycation sites detected in glycated HSA was reduced by 1 and 2, respectively, when 181.82 and 363.64 μM UroA was added. These could provide an insight into the mechanism of UroA inhibiting HSA glycation, and highlight its value as a promising glycation inhibitor in the prevention of diabetic complications.

High temperature limits the cultivation and utilization of cool-season plants in many regions worldwide. Recently, extreme hot waves swept across the globe in summer, leading to enormous economic loss. The evaluation and identification of genotypic variation in thermotolerance within species are critical to breeding for environmental adaptation and also provide potential materials to explore thermo-resistant mechanism in plants. Forty-two accessions of creeping bentgrass (Agrostis stolonifera), which is a cool-season perennial grass for turf and ecological remediation, were collected from 15 different countries. Physiological traits, namely, chlorophyll (Chl) content, electrolyte leakage, photochemical efficiency, performance index on absorption basis, leaf relative water content, and osmotic potential were used to evaluate the heat tolerance of these materials in controlled growth chambers and field during summer. Stay-green and early-aging genotypes were selected to further reveal the potential mechanism of tolerance to senescence and heat damage associated with alterations in Chl metabolism, antioxidant and photosynthetic capacity, and endogenous γ-aminobutyric acid (GABA). Findings showed that there were significant genetic variations in physiological traits among 41 materials in response to high temperature stress. The 13M, PROVIDENCE, and LOFTS L-93 were the top three accessions with superior tolerance to heat and summer stress than other materials in terms of laboratory and field tests. In response to heat stress, the stay-green genotype PROVIDENCE exhibited significantly higher photochemical efficiency, net photosynthetic rate, transpiration rate, and water use efficiency than the heat-susceptible W6 6570. Delayed leaf senescence in relation to less Chl loss was detected in the PROVIDENCE associated with maintenance of significantly higher expression levels of Chl-anabolic genes (AsCHLH, AsPBGD, and AsPOR) and lower Chl-catabolic gene AsPPH under heat stress. Genetic attributes, such as better capacity to scavenge reactive oxygen species and higher endogenous GABA content could play positive roles in alleviating heat-induced senescence, oxidative damage, and metabolic disturbance in the PROVIDENCE.

Background Integrins play a prominent role in osteogenic differentiation by transmitting both mechanical and chemical signals. Integrin expression is closely associated with tensile stress, which has a positive effect on osteogenic differentiation. We investigated the relationship between integrin αVβ3 and tensile stress. Methods Human fibroblasts were treated with c (RGDyk) and lentivirus transduction to inhibit function of integrin αVβ3. Y-15, cytochalasin D and verteporfin were used to inhibit phosphorylation of FAK, polymerization of microfilament and function of nuclear YAP, respectively. Fibroblasts were exposed to a cyclic tensile stress of 10% at 0.5 Hz, once a day for 2 h each application. Fibroblasts were harvested on day 4 and 7 post-treatment. The expression of ALP, RUNX2, integrin αVβ3, β-actin, talin-1, FAK, vinculin, and nuclear YAP was detected by Western blot or qRT-PCR. The expression and distribution of integrin αVβ3, vinculin, microfilament and nuclear YAP. Results Cyclic tensile stress was found to promote expression of ALP and RUNX2. Inhibition of integrin αVβ3 activation downregulated the rearrangement of microfilament and the expression of ALP, RUNX2 and nuclear YAP. When the polymerization of microfilament was inhibited the expression of ALP, RUNX2 and nuclear YAP were decreased. The phosphorylation of FAK induced by cyclic tensile stress reduced by the inhibition of integrin αVβ3. The expression of ALP and RUNX2 was decreased by inhibition of phosphorylation of FAK and inhibition of nuclear YAP. Conclusions Cyclic tensile stress promotes osteogenesis of human fibroblasts via integrin αVβ3-microfilament axis. Phosphorylation of FAK and nuclear YAP participates in this process.

Soil salinization is one of the main abiotic stress factors impacting the growth of crops and the agricultural industry today. Thus, we aimed to investigate the effects of H2O2 pretreatment on seed germination in Tartary buckwheat (Fagopyrum tataricum) seeds under salt stress and to evaluate this species’ salt tolerance. Through the preliminary experiment, this study used 50 mmol L−1 NaCl solution to induce seed stress. After soaking for 12 h in different H2O2 concentrations, seeds were laid in Petri dishes with 50 mmol L−1 NaCl for seven days and the germination parameters and physiological indicators were measured to screen the optimal H2O2 pretreatment concentration and the salt tolerance index. Our results indicated that pretreatment with 5–10 mmol L−1 H2O2 was most effective in alleviating NaCl’s impacts on the seeds’ germination parameters. Furthermore, the growth and material accumulation of seedlings was promoted, catalase, superoxide dismutase activity, and proline content were enhanced, and malondialdehyde content was reduced. Principal component analysis and stepwise regression revealed six key indicators that had a significant impact on the salt tolerance characteristics of F. tataricum, namely, germination potential, shoot fresh weight, root surface area, root average diameter, catalase activity, and superoxide dismutase activity.

Decarbonylative synthesis of thioethers from thioesters proceeds in the presence of a catalytic amount of [Rh(cod)Cl]2 (2 mol %). The protocol represents the first Rh-catalyzed decarbonylative thioetherification of thioesters to yield valuable thioethers. Notable features include the absence of phosphine ligands, inorganic bases, and other additives and excellent group tolerance to aryl chlorides and bromides that are problematic using other metals to promote decarbonylation. Gram scale synthesis, late-stage pharmaceutical derivatization, and orthogonal site-selective cross-couplings by C-S/C-Br cleavage are reported.

Drought is a serious outcome of climate change reducing the productivity of forage species under arid and semi-arid conditions worldwide. Diethyl aminoethyl hexanoate (DA-6), a novel plant growth regulator, has proven to be involved in the amelioration of critical physiological functions in many agricultural crops under various abiotic stresses, but the role of the DA-6 in improving seed germination has never been investigated under drought stress. The present study was carried out to elucidate the impact of the DA-6 priming on seeds germination of white clover under drought stress. Results showed that seed priming with the DA-6 significantly mitigated the drought-induced reduction in germination percentage, germination vigor, germination index, seed vigor index, root length, shoot length, and fresh weight after 7 days of seed germination. The DA-6 significantly increased the endogenous indole-3-acetic acid, gibberellin, and cytokinin content with marked reduction in abscisic acid content in seedlings under drought stress. In addition, the DA-6 significantly accelerated starch catabolism by enhancing the activities of hydrolases contributing toward enhanced soluble sugars, proline content and ameliorated the antioxidant defense system to enhance the ability of reactive oxygen species scavenging under drought stress. Furthermore, exogenous DA-6 application significantly increased dehydrins accumulation and upregulated transcript levels of genes encoding dehydrins (SK2, Y2SK, or DHNb) during seeds germination under water deficient condition. These findings suggested that the DA-6 mediated seeds germination and drought tolerance associated with changes in endogenous phytohormones resulting in increased starch degradation, osmotic adjustment, antioxidants activity, and dehydrins accumulation during seed germination under water deficient condition.

Persistent high temperature decreases the yield and quality of crops, including many important herbs. White clover (Trifolium repens) is a perennial herb with high feeding and medicinal value, but is sensitive to temperatures above 30 °C. The present study was conducted to elucidate the impact of changes in endogenous γ-aminobutyric acid (GABA) level by exogenous GABA pretreatment on heat tolerance of white clover, associated with alterations in endogenous hormones, antioxidant metabolism, and aquaporin-related gene expression in root and leaf of white clover plants under high-temperature stress. Our results reveal that improvement in endogenous GABA level in leaf and root by GABA pretreatment could significantly alleviate the damage to white clover during high-temperature stress, as demonstrated by enhancements in cell membrane stability, photosynthetic capacity, and osmotic adjustment ability, as well as lower oxidative damage and chlorophyll loss. The GABA significantly enhanced gene expression and enzyme activities involved in antioxidant defense, including superoxide dismutase, catalase, peroxidase, and key enzymes of the ascorbic acid–glutathione cycle, thus reducing the accumulation of reactive oxygen species and the oxidative injury to membrane lipids and proteins. The GABA also increased endogenous indole-3-acetic acid content in roots and leaves and cytokinin content in leaves, associated with growth maintenance and reduced leaf senescence under heat stress. The GABA significantly upregulated the expression of PIP1-1 and PIP2-7 in leaves and the TIP2-1 expression in leaves and roots under high temperature, and also alleviated the heat-induced inhibition of PIP1-1, PIP2-2, TIP2-2, and NIP1-2 expression in roots, which could help to improve the water transportation and homeostasis from roots to leaves. In addition, the GABA-induced aquaporins expression and decline in endogenous abscisic acid level could improve the heat dissipation capacity through maintaining higher stomatal opening and transpiration in white clovers under high-temperature stress.

Ten previously undescribed cassane diterpenoids, cassabonducins A–J, and eleven known compounds were isolated from the seeds of Caesalpinia bonduc. The structures of the undescribed compounds were elucidated by extensive analysis of spectroscopic data (IR, HRESIMS, and 1H, 13C and 2D NMR) and their absolute configurations were determined by the ECD data and single-crystal X-ray diffraction analysis. e-Caesalpin-Ⅶ was obtained from natural resources for the first time. Cassabonducin A possessed noteworthy inhibitory activity against LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages with IC50 value of 6.12 μM. Cassabonducin D and neocaesalpin N showed moderate α-glucosidase inhibition at the concentration of 50 μM with inhibitory capacities of 47.17% and 43.83%, respectively.

Sargassulfamide A (1), a unique amide derivative, was isolated from the seaweed Sargassum naozhouense. The structure of the new isolate was established by extensive analysis of various spectroscopic data and single-crystal X-ray diffraction.

Pathogens such as bacterial lipopolysaccharide (LPS) play an important role in promoting the production of the inflammatory cytokines interleukin-1 beta (IL-1β) and tumour necrosis factor-α (TNF-α) in response to infection or damage in microglia. However, whether different signalling pathways regulate these two inflammatory factors remains unclear. The protein kinase C (PKC) family is involved in the regulation of inflammation, and our previous research showed that the activation of the PKC pathway played a key role in the LPS-induced transformation of the adenosine A2A receptor (A2AR) from anti-inflammatory activity to pro-inflammatory activity under high glutamate concentrations. Therefore, in the current study, we investigated the role of PKC in the LPS-induced production of these inflammatory cytokines in mouse primary microglia. GF109203X, a specific PKC inhibitor, inhibited the LPS-induced expression of IL-1β messenger ribonucleic acid and intracellular protein in a dose-dependent manner. Moreover, 5 µM GF109203X prevented LPS-induced IL-1β expression but did not significantly affect LPS-induced TNF-α expression. PKC promoted IL-1β expression by regulating the activity of NF-κB but did not significantly impact the activity of ERK1/2. A2AR activation by CGS21680, an A2AR agonist, facilitated LPS-induced IL-1β expression through the PKC pathway at high glutamate concentrations but did not significantly affect LPS-induced TNF-α expression. Taken together, these results suggest a new direction for specific intervention with LPS-induced inflammatory factors in response to specific signalling pathways and provide a mechanism for A2AR targeting, especially after brain injury, to influence inflammation by interfering with A2AR.

Currently, it is still a huge challenge to prepare flame-retardant polymeric materials with excellent fire safety, high strength, good durability and processability. We here propose a H-bonding cross-linking strategy that can simultaneously endow polymers with excellent flame retardancy, non-dripping behavior and enhanced strength. In this work, a novel benzimidazole monomer, 2-(4-methoxycarbonyl-phenyl)-1H-benzimidazole-5-carboxylic acid methyl ester (PBM) has been designed as a H-bonding cross-linking monomer to prepare poly(ethylene terephthalate)-based copolyesters (PET-co-PBMs). Interestingly, along with the hydrogen bonding, the π-π stacking interactions from the benzimidazole groups also exist. Due to the formation of physical crosslinking network via hydrogen bonding and π-π stacking, the melt strength of copolyesters are greatly improved. Combining with char forming ability of benzimidazole, PET-co-PBMs display excellent fire safety. Moreover, PET-co-PBMs also exhibit higher glass transition temperature, higher mechanical strength and good processability. This work provides a promising strategy to design polymers with high strength, good processability, excellent flame retardance and anti-dripping performance.

β-sitosterol influences amino acids, carbohydrates, organic acids, and other metabolite metabolism and homeostasis largely contributing to better tolerance to water stress in white clover. β-sitosterol (BS) could act as an important plant growth regulator when plants are subjected to harsh environmental conditions. Objective of this study was to examine effects of BS on growth and water stress tolerance in white clover based on physiological responses and metabolomics. White clover was pretreated with or without BS and then subjected to water stress for 7 days in controlled growth chambers. Physiological analysis demonstrated that exogenous application of BS (120 μM) could significantly improve stress tolerance associated with better growth performance and photosynthesis, higher leaf relative water content, and less oxidative damage in white clover in response to water stress. Metabolic profiling identified 78 core metabolites involved in amino acids, organic acids, sugars, sugar alcohols, and other metabolites in leaves of white clover. For sugars and sugar alcohol metabolism, the BS treatment enhanced the accumulation of fructose, glucose, maltose, and myo-inositol contributing to better antioxidant capacity, growth maintenance, and osmotic adjustment in white clover under water stress. The application of BS was inclined to convert glutamic acid into proline, 5-oxoproline, and chlorophyll instead of going to pyruvate and alanine; the BS treatment did not significantly affect intermediates of tricarboxylic acid cycle (citrate, aconitate, and malate), but promoted the accumulation of other organic acids including lactic acid, glycolic acid, glyceric acid, shikimic acid, galacturonic acid, and quinic acid in white clover subjected to water stress. In addition, cysteine, an important antioxidant metabolite, was also significantly improved by BS in white clover under water stress. These altered amino acids and organic acids metabolism could play important roles in growth maintenance and modulation of osmotic and redox balance against water stress in white clover. Current findings provide a new insight into BS-induced metabolic homeostasis related to growth and water stress tolerance in plants.

Creeping breakdown caused by metal particles on the silicone rubber/XLPE interface of prefabricated cable joints often happens. Study on the development process of such insulation defect-led partial discharge (PD) can serve as a basis for the assessment of its severity level. In this paper, metal particles are sandwiched on the rubber/XLPE interface of a 35 kV prefabricated cable joint to simulate a creeping defect.

Gestational diabetes mellitus (GDM) is known as different degree glucose intolerance that is initially identified during pregnancy. MicroRNAs (miRs) may be a potential candidate for treatment of GDM. Herein, we suggested that miR‐351 could be an inhibitor in the progression of GDM via the phosphoinositide 3‐kinase/protein kinase B (PI3K/AKT) pathway. Microarray analysis was used to identify differentially expressed genes and predict miRs regulating flotillin 2 (FLOT2). Target relationship between miR‐351 and FLOT2 was verified. Gestational diabetes mellitus mice were treated with a series of mimic, inhibitor and small interfering RNA to explore the effect of miR‐351 on insulin resistance (IR), cell apoptosis in pancreatic tissues and liver gluconeogenesis through evaluating GDM‐related biochemical indexes, as well as expression of miR‐351, FLOT2, PI3K/AKT pathway‐, IR‐ and liver gluconeogenesis‐related genes. MiR‐351 and FLOT2 were reported to be involved in GDM. FLOT2 was the target gene of miR‐351. Gestational diabetes mellitus mice exhibited IR and liver gluconeogenesis, up‐regulated FLOT2, activated PI3K/AKT pathway and down‐regulated miR‐351 in liver tissues. Additionally, miR‐351 overexpression and FLOT2 silencing decreased the levels of FLOT2, phosphoenolpyruvate carboxykinase, glucose‐6‐phosphatase, fasting blood glucose, fasting insulin, total cholesterol, triglyceride, glyeosylated haemoglobin and homeostasis model of assessment for IR index (HOMA‐IR), extent of PI3K and AKT phosphorylation, yet increased the levels of HOMA for islet β‐cell function, HOMA for insulin sensitivity index and glucose transporter 2 expression, indicating reduced cell apoptosis in pancreatic tissues and alleviated IR and liver gluconeogenesis. Our results reveal that up‐regulation of miR‐351 protects against IR and liver gluconeogenesis by repressing the PI3K/AKT pathway through regulating FLOT2 in GDM mice, which identifies miR‐351 as a potential therapeutic target for the clinical management of GDM.

Persistent high temperature inhibits plant growth and development. The γ-aminobutyric acid (GABA) plays a key role in heat tolerance in plants. The increase in endogenous GABA level induced by exogenous GABA effectively alleviated heat damage in creeping bentgrass. Global investigation into mRNAs and miRNAs found that the regulation of HSFs pathways and enhanced carbon metabolism, biosynthesis of amino acids, and plant hormone signal transduction were important adaptive response to heat stress. GABA-induced heat tolerance was closely related to phenylpropanoid biosynthesis, further improved HSFs pathways, and the upregulation of CAD3, ACS, AER, and CA1 associated with lignin and lipids biosynthesis, photosynthesis and water use, and antioxidant defense. Dramatic changes of miR398s, cca-miR156b, aly-miR159c-3p, and ata-miR408-3p had a close correlation with heat-survival. The especial vvi-miR845c, ama-miR156, and other novel miRNAs such as novel-24223, novel-2964, and novel-10098 could be involved in GABA-regulated heat tolerance. The integrated analysis of mRNAs and miRNAs facilitates uncovering of adaptative response in perennial plants under high temperature environmental condition and also reveals that GABA acting as a critical plant growth regulator induces heat tolerance in creeping bentgrass involved in physiological, transcriptional, and post-transcriptional regulation. Particularly, current results provide some key candidate genes and miRNAs for further investigating their potential roles in heat tolerance in non-model plants.

To mimic the velocity-sensitive ability of the human skin, we fabricate a class of "solid-liquid" elastomers (SLEs) by interpenetrating polyborosiloxane (PBS) with polydimethylsiloxane (PDMS). PBS forms a dynamic network through boron/oxygen dative bonds, while PDMS is covalently cross-linked to form a permanent network. The permanent network affords a scaffold for the dynamic network, endowing SLEs with high elasticity and structural stability, thereby overcoming the inherent drawbacks such as fluidity and irreversible deformation of conventional solid-liquid materials. Meanwhile, the dissociation and association of the dynamic network is time-dependent. Thus, the modulus of SLEs varies with strain rates, and if the SLEs contain carbon nanotubes, their electric conductivity is also responsive to strain rates. This property can be utilized to fabricate skin-like sensors with the ability to distinguish different contact velocities. Moreover, the dynamic network can dissipate energy and be repaired, leading to the high stretchability and self-healing performance of SLEs.

As part of our ongoing search for novel and bioactive natural products in Karst plants, two new sesqui-neolignans, difengpienol A (1) and difengpienol B (2), together with two known analogues (3 and 4), were isolated from the stem bark of Illicium difengpi. Their structures were elucidated by analysis of spectroscopic data. Difengpienol A (1) possessed a unique 1, 4-dibenzodioxocine moiety. All isolates were evaluated for inhibitory effects against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages cells. Compounds 1 and 2 showed moderate inhibitory effects on NO production with IC50 values of 16.9 and 23.8 μM. A biosynthetic pathway was also proposed for 1 and 2.

Chrysin is a natural product of a flavonoid compound. Chemically, chrysin consists of two phenyl rings (A and B) and a heterocyclic ring (C). Biologically, chrysin exerts many different physiological activities. In recent years, with the in-depth development for more active drugs, the synthesis and biological activities of chrysin derivatives have been well studied. Besides, structure-activity relationship of chrysin revealed that the chemical construction meets the critical chemical structural necessities of flavonoids for numerous pharmacological activities. It is generally believed that modified chrysin could be more potent than unmodified chrysin. Different modification in the rings of chrysin could possess various degrees of biological activities. This review aims to summarize the mechanism for the activities of chrysin and its derivatives in different rings. We also explored the relationship between biological function and structure-activity of substituted chrysin derivatives with different functional groups. The influence of chrysin derivatives on the proliferation and apoptosis of cancer cells is also investigated. Development of novel drugs based on the biological functions of chrysin could better improve clinical outcomes of affected population, especially for tumor patients and diabetic patients.