Low-Temperature Adaptive Dual-Network MXene Nanocomposite Hydrogel as Flexible Wearable Strain Sensors.

Flexible electronic devices and conductive materials can be used as wearable sensors to detect human motions. However, the existing hydrogels generally have problems of weak tensile capacity, insufficient durability, and being easy to freeze at low temperatures, which greatly affect their application in the field of wearable devices. In this paper, glycerol was partially replaced by water as the solvent, agar was thermally dissolved to initiate acrylamide polymerization, and MXene was used as a conductive filler and initiator promoter to form the double network MXene-PAM/Agar organic hydrogel. The presence of MXene makes the hydrogel produce more conductive paths and enforces the hydrogel's higher conductivity (1.02 S·m-1). The mechanical properties of hydrogels were enhanced by the double network structure, and the hydrogel had high stretchability (1300%). In addition, the hydrogel-based wearable strain sensor exhibited good sensitivity over a wide strain range (GF = 2.99, 0-200% strain). The strain sensor based on MXene-PAM/Agar hydrogel was capable of real-time monitoring of human movement signals such as fingers, wrists, arms, etc. and could maintain good working conditions even in cold environments (-26 °C). Hence, we are of the opinion that delving into this hydrogel holds the potential to broaden the scope of utilizing conductive hydrogels as flexible and wearable strain sensors, especially in chilly environments.

Conductive, self-healing, and antibacterial Ag/MXene-PVA hydrogel as wearable skin-like sensors.

The rapid development of flexible electronic technology has led to the in-depth study of flexible wearable sensors to achieve accurate sensing under different external stimuli. However, it is still a huge challenge to develop hydrogel-based wearable skin-like sensors with super ductility, high sensitivity, and self-healing properties. Herein, the Ti3C2 type of MXene was synthesized, and the Ag/MXene nanocomplexes were incorporated into polyvinyl alcohol-borax matrix to construct a novel composite hydrogel as the multifunctional nanofillers, which could bring both improved properties and novel functionalities. The Ag/MXene-Poly (vinyl alcohol) (PVA) hydrogel displayed integrated merits of highly strain sensitive (GF = 3.26), self-healing (within 10 min, 91% healing efficiency), and excellent antibacterial activity. The hydrogel could be assembled into a wearable skin-like sensor to monitor human movement, including large deformations (finger, elbow, wrist, and knee bending) and tiny deformations (mouth's movement and throat vocalization) in real time. Therefore, this work shed a new light on the development of flexible wearable skin-like sensors for the personalized healthcare monitoring, human-machine interfaces, and artificial intelligence.

Multi-objective Optimization and Control of Self-Heat Recuperative Azeoropic Distillation for Separating an Ethanol/Water Mixture.

Azeotropic distillation is an important method for the separation of an ethanol/water mixture, while the main disadvantage of azeotropic distillation is its high energy consumption. Since the self-heat recuperation technology can effectively recover and utilize the heat of effluent stream in thermal processes, it is introduced into the ethanol dehydration process. The conventional azeotropic distillation and self-heat recuperative azeotropic distillation (SHRAD) are simulated and optimized with multiple objectives. There exists a design point in the Pareto solution set for which the total annual cost is the lowest, the thermodynamic efficiency is the highest, and the CO2 emission is the least. Based on the specified design, the dynamic characteristics of the SHRAD configuration are studied, and two control structures are proposed. The improved control structure of the SHRAD process works well under the feed flowrate and composition disturbance, and the SHRAD system can obtain a high-purity ethanol product. The results show that the SHRAD process has significant advantages over conventional azeotropic distillation in terms of economic and environmental benefits. In addition, an effective control structure can ensure the stable operation of the SHRAD process.

Medium and Long Chain Fatty Acids Differentially Modulate Apoptosis and Release of Inflammatory Cytokines in Human Liver Cells.

Medium chain fatty acids (MCFA) can be more easily absorbed and supply energy more rapidly than long chain fatty acids (LCFA). However, little is known about the inflammatory response by the treatment of MCFA in human liver cells. Thus this study used human liver cells (LO2) to evaluate the effects of MCFA on apoptosis and inflammatory response. Tetrazolim-based colorimetric assay and lactate dehydrogenase assay were used to measure the viability of LO2 cells, isolated spleens and liver cells from BALB/C mice. Inverted fluorescence microscopy and flow cytometry were used to assess the cell apoptosis. Activity of superoxide dismutase and malondialdehyde level were measured to determine the oxidative damage. mRNA or protein levels of classical pro-inflammatory cytokines were analyzed by quantitative real-time polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay and western blotting. The results showed that the liver cells treated with the fatty acids at 200 µM for 24 h exhibited good viability. Fatty acids induced inflammatory cytokines at transcriptional and translational levels to a lesser extent than lipopolysaccharide. LCFA (oleic acid) up-regulated tumor necrosis fator-α, monocyte chemoattractant-1 and interleukin-1ß while down-regulated IL-6 and IL-8 secretion to a higher extent than MCFA in mRNA and protein levels. These findings suggested that MCFA may induce apoptosis to a less extent and exert more gentle inflammation than LCFA in human liver cells.

Medium-chain fatty acid reduces lipid accumulation by regulating expression of lipid-sensing genes in human liver cells with steatosis.

Accumulation of lipids in the liver can lead to cell dysfunction and steatosis, an important factor in pathogenesis causing non-alcoholic fatty liver disease. The mechanisms related to lipid deposition in the liver, however, remain poorly understood. This study was aimed to investigate the effects of medium-chain fatty acid (MCFA) on the lipolysis and expression of lipid-sensing genes in human liver cells with steatosis. A cellular steatosis model, which is suitable to experimentally investigate the impact of fat accumulation in the liver, was established in human normal liver cells (LO2 cells) with a mixture of free fatty acids (oleate/palmitate, 2:1) at 200 µm for 24 h incubation. MCFA was found to down-regulate expression of liver X receptor-α, sterol regulatory element binding protein-1, acetyl-CoA carboxylase, fatty acid synthase, CD 36 and lipoprotein lipase in this cellular model, and have positive effects on adipose triglyceride lipase and hormone-sensitive lipase. These results suggest that MCFA may reduce lipid accumulation by regulating key lipid-sensing genes in human liver cells with steatosis.

Effects of Long-Chain and Medium-Chain Fatty Acids on Apoptosis and Oxidative Stress in Human Liver Cells with Steatosis.

Nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity-related metabolic complications, which caused by excess energy intake and physical inactivity apart from genetic defects. The mechanisms that promote disease progression from NAFLD to further liver injury are still unclear. We hypothesize that the progression involved "2nd hit" is strongly influenced by the type of fatty acids in diets. Flow cytometric analysis showed that medium-chain fatty acid (MCFA) markedly decreased the percentage of late apoptotic and necrotic cells compared with long-chain fatty acid (LCFA), and MCFA inhibited the activities of caspase-3 and -9 in human liver cells with steatosis. Western blot analysis found that the levels of inflammatory markers (interleukin [IL]-6, IL-1-ß, and tumor necrosis factor-α) were substantially reduced by MCFA compared with LCFA. Proteomic analysis further showed that LCFA inhibited the expression of antioxidant enzymes, and increased the expression of proteins associated with oxidative stress. It was found that LCFA (palmitate), not MCFA induced apoptosis, oxidative stress and chronic inflammatory responses in the hepatic cells with steatosis. In conclusion, reasonable selection of dietary fats has potential to translate therapeutically by ameliorating disease progression in patients with NAFLD.

Behavior of the edible seaweed Sargassum fusiforme to copper pollution: short-term acclimation and long-term adaptation.

Aquatic agriculture in heavy-metal-polluted coastal areas faces major problems due to heavy metal transfer into aquatic organisms, leading to various unexpected changes in nutrition and primary and/or secondary metabolism. In the present study, the dual role of heavy metal copper (Cu) played in the metabolism of photosynthetic organism, the edible seaweed Sargassum fusiforme, was evaluated by characterization of biochemical and metabolic responses using both 1H NMR and GC-MS techniques under acute (47 µM, 1 day) and chronic stress (8 µM, 7 days). Consequently, photosynthesis may be seriously inhibited by acute Cu exposure, resulting in decreasing levels of carbohydrates, e.g., mannitol, the main products of photosynthesis. Ascorbate may play important roles in the antioxidant system, whose content was much more seriously decreased under acute than that under chronic Cu stress. Overall, these results showed differential toxicological responses on metabolite profiles of S. fusiforme subjected to acute and chronic Cu exposures that allowed assessment of impact of Cu on marine organisms.