Chestnut-Tannin-Crosslinked, Antibacterial, Antifreezing, Conductive Organohydrogel as a Strain Sensor for Motion Monitoring, Flexible Keyboards, and Velocity Monitoring

Flexible sensing devices (FSDs) fabricated using conductive hydrogels have attracted researchers’ extensive enthusiasm in recent years due to their versatility. Considering the complexity of their application environments, the integration of various functional characteristics (e.g., excellent mechanical, antibacterial, and antifreezing properties) is an important guarantee for FSDs to stably perform their applications in different environments. Herein, we developed a multifunctional conductive polyvinyl alcohol (PVA) organohydrogel PVA-CT-Ag-Al-Gly (PCAAG) by using a green, natural, and cheap biomass, chestnut tannin (CT), as a crosslinking agent, nano-silver particles (AgNPs) as an antimicrobial agent, aluminum trichloride (AlCl3) as a conducting medium, and the mixed water–glycerol as the solvent system. In this organohydrogel system, CT acted not only as the reducing and stabilizing agent for the preparation of antibacterial AgNPs but also as the crosslinking agent owing to its strong multiple hydrogen bonding interactions with PVA, realizing its multifunctional application. The PCAAG organohydrogel possessed outstanding physical and mechanical properties (350.54% of the maximum fracture strain and 1.55 MPa of the maximum tensile strength), considerable bacteriostatic effects against both Escherichia coli and Staphylococcus aureus, and excellent freeze resistance (it could function normally at −20 °C). The motion-monitoring sensor based on the PCAAG organohydrogel exhibited excellent specificity recognition for both large-amplitude (e.g., elbow bending, wrist bending, finger bending, running and walking, etc.) and small-amplitude (frowning and swallowing) human movements. The flexible keyboard constructed by using the PCAAG organohydrogel could easily achieve the transformation between digital signals and electrical signals, and the signal output had both specificity and stability. The velocity-monitoring sensor fabricated by using the PCAAG organohydrogel could accurately measure the speed of the object movement (less than 3% of relative error). In short, the present PCAAG organohydrogel solves the problems of the single application environment and a few application scenarios of traditional conductive hydrogels and possesses remarkable application potential as a multifunctional FSD in many fields such as artificial intelligence, sport management, soft robots, and human–computer interface

A methyl parathion electrochemical sensor based on Nano-TiO₂, graphene composite film modified electrode

A methyl parathion electrochemical sensor based on nano-TiO2 and graphene composite film modified glassy carbon electrode has been developed. The electrochemical behavior of MP at the sensor was investigated by cyclic voltammetry and linear sweep voltammetry. Scanning electron microscopy was used to characterize the surface morphology of nano-TiO2 and graphene composite film. Compared with a bare glassy carbon electrode or a mono-film modified electrode, the redox peak currents of methyl parathion on the composite film modified electrode improved greatly, indicating that the sensor showed good catalytic effects. The optimal experimental condition was obtained. The results indicated that the linear sweep voltammetry responses of methyl parathion, in pH 5.2 acetate buffer solution with open-circuit accumulation for 2 min, were linear with concentrations of methyl parathion in two ranges of 0.002∼5 μM and 5∼100 μM. The linear equations were iPc(μA) = 0.0136 + 4.965cMP(μM) (R12 = 0.9911) and iPc(μA) = 21.87 + 0.8206cMP(μM) (R22 = 0.9914), respectively. The detection limit was 1.0 nM (S/N = 3). The sensor exhibited high sensitivity and good reproducibility as well as certain anti-interference ability. It was applied to the determination of residual MP in fresh apple sample with the recovery of 92%∼102%. The result was satisfactory.</p

Reduction of [VO₂(ma)₂]^- and [VO₂(ema)₂]^- by Ascorbic Acid and Glutathione: Kinetic Studies of Pro-Drugs for the Enhancement of Insulin Action^†

To shed light on the role of V(V) complexes as pro-drugs for their V(IV) analogues, the kinetics of the reduction reactions of [VO2(ma)2]- or [VO2(ema)2]- (Hma = maltol, Hema = ethylmaltol), with ascorbic acid or glutathione, have been studied in aqueous solution by spectrophotometric and magnetic resonance methods. EPR and 51V NMR studies suggested that the vanadium(V) in each complex was reduced to vanadium(IV) during the reactions. All the reactions studied showed first-order kinetics when the concentration of ascorbic acid or glutathione was in large excess and the observed first-order rate constants have a linear relationship with the concentrations of reductant (ascorbic acid or glutathione). Potentiometric results revealed that the most important species in the neutral pH range is [VO2(L)2]- for the V(V) system where L is either ma- or ema-. An acid dependence mechanism was proposed from kinetic studies with varying pH and varying maltol concentration. The good fits of the second order rate constant versus pH or the total concentration of maltol, and the good agreement of the constants obtained between fittings, strongly supported the mechanism. Under the same conditions, the reaction rate of [VO2(ma)2]- with glutathione is about 2000 times slower than that of [VO2(ma)2]- with ascorbic acid, but an acid dependence mechanism can also be used to explain the results for the reduction with glutathione. Replacing the methyl group in maltol with an ethyl group has little influence on the reduction rate with ascorbic acid, and the kinetics are the same no matter whether [VO2(ma)2]- or [VO2(ema)2]- is reduced

Image_2_Contrasting distribution of enzyme activities in the rhizosphere of European beech and Norway spruce.tif

Recent policies and silvicultural management call for forest regeneration that involve the selection of tree species able to cope with low soil nutrient availability in forest ecosystems. Understanding the impact of different tree species on the rhizosphere processes (e.g., enzyme activities) involved in nutrient mobilisation is critical in selecting suitable species to adapt forests to environmental change. Here, we visualised and investigated the rhizosphere distribution of enzyme activities (cellobiohydrolase, leucine-aminopeptidase, and acid phosphomonoesterase) using zymography. We related the distribution of enzyme activities to the seedling root morphological traits of European beech (Fagus sylvatica) and Norway spruce (Picea abies), the two most cultivated temperate tree species that employ contrasting strategies in soil nutrient acquisition. We found that spruce showed a higher morphological heterogeneity along the roots than beech, resulting in a more robust relationship between rhizoplane-associated enzyme activities and the longitudinal distance from the root apex. The rhizoplane enzyme activities decreased in spruce and increased in beech with the distance from the root apex over a power-law equation. Spruce revealed broader rhizosphere extents of all three enzymes, but only acid phosphomonoesterase activity was higher compared with beech. This latter result was determined by a larger root system found in beech compared with spruce that enhanced cellobiohydrolase and leucine-aminopeptidase activities. The root hair zone and hair lengths were significant variables determining the distribution of enzyme activities in the rhizosphere. Our findings indicate that spruce has a more substantial influence on rhizosphere enzyme production and diffusion than beech, enabling spruce to better mobilise nutrients from organic sources in heterogeneous forest soils.</p

DataSheet_1_Contrasting distribution of enzyme activities in the rhizosphere of European beech and Norway spruce.docx

Recent policies and silvicultural management call for forest regeneration that involve the selection of tree species able to cope with low soil nutrient availability in forest ecosystems. Understanding the impact of different tree species on the rhizosphere processes (e.g., enzyme activities) involved in nutrient mobilisation is critical in selecting suitable species to adapt forests to environmental change. Here, we visualised and investigated the rhizosphere distribution of enzyme activities (cellobiohydrolase, leucine-aminopeptidase, and acid phosphomonoesterase) using zymography. We related the distribution of enzyme activities to the seedling root morphological traits of European beech (Fagus sylvatica) and Norway spruce (Picea abies), the two most cultivated temperate tree species that employ contrasting strategies in soil nutrient acquisition. We found that spruce showed a higher morphological heterogeneity along the roots than beech, resulting in a more robust relationship between rhizoplane-associated enzyme activities and the longitudinal distance from the root apex. The rhizoplane enzyme activities decreased in spruce and increased in beech with the distance from the root apex over a power-law equation. Spruce revealed broader rhizosphere extents of all three enzymes, but only acid phosphomonoesterase activity was higher compared with beech. This latter result was determined by a larger root system found in beech compared with spruce that enhanced cellobiohydrolase and leucine-aminopeptidase activities. The root hair zone and hair lengths were significant variables determining the distribution of enzyme activities in the rhizosphere. Our findings indicate that spruce has a more substantial influence on rhizosphere enzyme production and diffusion than beech, enabling spruce to better mobilise nutrients from organic sources in heterogeneous forest soils.</p

Image_1_Contrasting distribution of enzyme activities in the rhizosphere of European beech and Norway spruce.tif

Recent policies and silvicultural management call for forest regeneration that involve the selection of tree species able to cope with low soil nutrient availability in forest ecosystems. Understanding the impact of different tree species on the rhizosphere processes (e.g., enzyme activities) involved in nutrient mobilisation is critical in selecting suitable species to adapt forests to environmental change. Here, we visualised and investigated the rhizosphere distribution of enzyme activities (cellobiohydrolase, leucine-aminopeptidase, and acid phosphomonoesterase) using zymography. We related the distribution of enzyme activities to the seedling root morphological traits of European beech (Fagus sylvatica) and Norway spruce (Picea abies), the two most cultivated temperate tree species that employ contrasting strategies in soil nutrient acquisition. We found that spruce showed a higher morphological heterogeneity along the roots than beech, resulting in a more robust relationship between rhizoplane-associated enzyme activities and the longitudinal distance from the root apex. The rhizoplane enzyme activities decreased in spruce and increased in beech with the distance from the root apex over a power-law equation. Spruce revealed broader rhizosphere extents of all three enzymes, but only acid phosphomonoesterase activity was higher compared with beech. This latter result was determined by a larger root system found in beech compared with spruce that enhanced cellobiohydrolase and leucine-aminopeptidase activities. The root hair zone and hair lengths were significant variables determining the distribution of enzyme activities in the rhizosphere. Our findings indicate that spruce has a more substantial influence on rhizosphere enzyme production and diffusion than beech, enabling spruce to better mobilise nutrients from organic sources in heterogeneous forest soils.</p

Additional file 5 of GLP2-GLP2R signal affects the viability and EGFR-TKIs sensitivity of PC9 and HCC827 cells

Additional file 5. The original blots of Figures 3C–D and 5B

Additional file 4 of GLP2-GLP2R signal affects the viability and EGFR-TKIs sensitivity of PC9 and HCC827 cells

Additional file 4. The original blots of Figure 5C

Additional file 6 of GLP2-GLP2R signal affects the viability and EGFR-TKIs sensitivity of PC9 and HCC827 cells

Additional file 6. The original blots of Figure 3E

Additional file 1 of GLP2-GLP2R signal affects the viability and EGFR-TKIs sensitivity of PC9 and HCC827 cells

Additional file 1. The original blots of Figure 3A