Super-Flexible Water-Proof Actuators.

Humidity-responsive materials hold broad application prospects in sensing, energy production, and other fields. Particularly, humidity-sensitive, flexibility, and water resistance are pivotal factors in the development of optimized humidity-responsive materials. In this study, hydrophobic linear polyurethane and hydrophilic 4-vinylphenylboronic acid (4-VPBA) form a semi-intercross cross-linking network. This copolymer of polyurethane exhibits excellent humidity-sensitive, mechanical properties, and water resistance. Its maximum tensile strength and maximum elongation can reach 40.56 MPa and 543.47%, respectively. After being immersed in water at various temperatures for 15 days, it exhibited a swelling ratio of only 3.28% in water at 5 °C and 9.58% in water at 70 °C. While the presence of 4-VPBA network imparts humidity-sensitive, reversible, and multidirectional bending abilities, under the stimulus of water vapor, it can bend 43° within 1.4 s. The demonstrated material surpasses current bidirectional humidity actuators in actuating ability. Based on these characteristics, automatically opening waterproof umbrellas and windows, as well as bionic-arms, crawling robots, and self-propelled boats, are successfully developed.

Earthworm-Inspired Co/Co3O4/CoF2@NSC Nanofibrous Electrocatalyst with Confined Channels for Enhanced ORR/OER Performance.

The rational construction of highly active and durable oxygen-reactive electrocatalysts for oxygen reduction/evolution reaction (ORR/OER) plays a critical role in rechargeable metal-air batteries. It is pivotal to achieve optimal utilization of electrocatalytically active sites and valid control of the high specific internal surface area. Inspiration for designing electrocatalysts can come from nature, as it is full of precisely manipulated and highly efficient structures. Herein, inspired by earthworms fertilizing soil, a 3D carbon nanofibrous electrocatalyst with multiple interconnected nanoconfined channels, cobalt-based heterojunction active particles and enriched N, S heteroatoms (Co/Co3O4/CoF2@NSC with confined channels) is rationally designed, showing superior bifunctional electrocatalytic activity in alkaline electrolyte, even outperforming that of benchmark Pt/C-RuO2 catalyst. This work demonstrates a new method for porous structural regulation, in which the internal confined channels within the nanofibers are controllably formed by the spontaneous migration of cobalt-based nanoparticles under a CO2 atmosphere. Theoretical analysis reveals that constructing Co/Co3O4/CoF2@NSC electrocatalyst with confined channels can greatly adjust the electron distribution, effectively lower the reaction barrier of inter-mediate and reduce the OER/ORR overpotential. This work introduces a novel and nature-inspired strategy for designing efficient bifunctional electrocatalysts with well-designed architectures.

Ternary Heteroatomic Doping Induced Microenvironment Engineering of Low Fe-N4-Loaded Carbon Nanofibers for Bifunctional Oxygen Electrocatalysis.

Fabricating highly efficient and long-life redox bifunctional electrocatalysts is vital for oxygen-related renewable energy devices. To boost the bifunctional catalytic activity of Fe-N-C single-atom catalysts, it is imperative to fine-tune the coordination microenvironment of the Fe sites to optimize the adsorption/desorption energies of intermediates during oxygen reduction/evolution reactions (ORR/OER) and simultaneously avoid the aggregation of atomically dispersed metal sites. Herein, a strategy is developed for fabricating a free-standing electrocatalyst with atomically dispersed Fe sites (≈0.89 wt.%) supported on N, F, and S ternary-doped hollow carbon nanofibers (FeN4 -NFS-CNF). Both experimental and theoretical findings suggest that the incorporation of ternary heteroatoms modifies the charge distribution of Fe active centers and enhances defect density, thereby optimizing the bifunctional catalytic activities. The efficient regulation isolated Fe centers come from the dual confinement of zeolitic imidazole framework-8 (ZIF-8) and polymerized ionic liquid (PIL), while the precise formation of distinct hierarchical three-dimensional porous structure maximizes the exposure of low-doping Fe active sites and enriched heteroatoms. FeN4 -NFS-CNF achieves remarkable electrocatalytic activity with a high ORR half-wave potential (0.90 V) and a low OER overpotential (270 mV) in alkaline electrolyte, revealing the benefit of optimizing the microenvironment of low-doping iron single atoms in directing bifunctional catalytic activity.

Novel Strain of Paenibacillus phyllosphaerae CS-148 for the Direct Hydrolysis of Raw Starch into Glucose: Isolation and Fermentation Optimization.

The conventional process for converting starch to glucose is energy-intensive. To lower the cost of this process, a novel strain of Paenibacillus phyllosphaerae CS-148 was isolated and identified, which could directly hydrolyze raw starch into glucose and accumulate glucose in the fermentation broth. The effects of different organic and inorganic nitrogen sources, the culture temperature, the initial pH, and the agitation speed on the yield of glucose were optimized through the one-factor-at-a-time method. Nine factors were screened by Plackett-Burman design, and three factors (raw corncob starch, yeast extract and (NH4)2SO4) had significant effects on glucose yield. Three significant factors were further optimized using Box-Behnken design. Under the optimized fermentation conditions (raw corncob starch 40.4 g/L, yeast extract 4.27 g/L, (NH4)2SO4 4.39 g/L, KH2PO4 2 g/L, MgSO4`7H2O 2 g/L, FeSO4`7H2O 0.02 g/L, NaCl 2 g/L, KCl 0.5 g/L, inoculums volume 4%, temperature 35 °C, agitation rate 150 rpm, and initial pH 7.0), the maximum glucose yield reached 17.32 ± 0.46 g/L, which is 1.33-fold compared to that by initial fermentation conditions. The maximum conversion rate and glucose productivity were 0.43 ± 0.01 g glucose/g raw corn starch and 0.22 ± 0.01 g/(L·h), respectively. These results implied that P. phyllosphaerae CS-148 could be used in the food industry or fermentation industry at a low cost.

All-In-One Evaporators for Efficient Solar-Driven Simultaneous Collection of Water and Electricity.

The shortage of fossil fuels and freshwater resources has become a serious global issue. Using solar energy to extract clean water with a photothermal conversion technology is a green and sustainable desalination method. Integrated electricity generation during the desalination process maximizes energy utilization efficiency. Herein, a solar-driven steam and electricity generation (SSEG) system based on an all-in-one evaporator is prepared via a scalable technology. Carbon black is selected as the absorber for solar energy harvesting as well as the functional substance for simultaneous electricity generation. Fabric substrate with flexible structure, porous channel, and capillary effect is vital for directional brine supply, multiple solar absorption, and thermal management. The high evaporation rate (1.87 kg m-2  h-1 ) and voltage output (324 mV) can be achieved with an all-in-one device. The stable electricity output can be maintained over 40000 s. The SSEG performance remains constant after 15 operation cycles or 20 wash cycles. The integrated device balances excellent effectiveness and practicality, providing a viable path for clean desalination and electricity generation.

Multi-Unit Needleless Electrospinning for One-Step Construction of 3D Waterproof MF-PVA Nanofibrous Membranes as High-Performance Air Filters.

The airborne particulate matter (PM) seriously threatens people's health. Personal protective equipment with electrospun nanofibers is an effective method to make people away from air pollutants. Herein, 3D waterproof melamine-formaldehyde polyvinyl alcohol (MF-PVA) nanofibrous membranes are fabricated by a one-step method combining multi-unit needleless electrospinning and a thermal treatment device in a line. 3D nanofibrous structures can be controlled by adjusting the solution concentration of each unit. The PVA nanofibrous membranes become waterproof after cross-linking with MF resin in the following thermal treatment device. The optimized MF-PVA nanofibrous membrane shows excellent air filtration performance (97.3% for PM0.3 , 100% for PM1.0 , and 100% for PM2.5 ) and low air resistance (76 Pa). These 3D waterproof MF-PVA nanofibrous membranes exhibit ultra-stable performance in various practical environments.

A Multiple Remotely Controlled Platform from Recyclable Polyurethane Composite Network with Shape-Memory Effect and Self-Healing Ability.

Stimuli-responsive materials can transform from temporary to permanent shapes by specific external triggers. However, the damage might inevitably occur to them when exposed to complex environments, causing a significant reduction in their lifetime and quality. In this study, recyclable remotely controlled shape-changing polyurethane composite with self-healing compacity is developed from polyethylene glycol, polytetrahydrofuran diol using isophorone diisocyanate as crosslinker. After the incorporation of magnetite nanoparticles (MNPs), remote heating could be generated by near-infrared irradiation and alternating magnetic fields. The results show that MNPs are uniformly distributed in the smart networks, resulting in tunable temperature changes of the polymer composite material under various direct/indirect triggering in bending experiments, presenting different shape recovery rates. Moreover, to enhance the self-healing capability, a disulfide bond is introduced into the polymer networks, and the results show that highly efficient and rapid healing could be achieved from tensile tests, scanning electron microscopy as well as optical microscopy. Additionally, the synergistic effect of transesterification and the dynamic exchange of disulfide bonds brin the networks reproducibility for recycling use. The obtained material is promising to be an alternative material for soft robots and smart sensors.

Effects of laccase and cellulase on saccharification of barley malt.

Improving saccharification of barley malt is beneficial to promoting economic benefits of beer brewers, but there are few detailed reports on the application of cellulase and laccase in barley malt. So, barley malt was pretreated by cellulase and laccase, and the malt wort and brewer's spent grains were analyzed by HPLC, FTIR and SEM in this study. The concentration of malt wort was increased significantly to 8.1 (° Bx), which increased by 28.6% after barley malt was pretreated by cellulase, but laccase could not improve saccharification of barley malt. Through analysis of sugar in malt wort and cellulose and lignin components as well as physical and chemical structures of brewer's spent grains, the increase in sugar content in malt wort was mainly due to the increase in glucose because of hydrolysis of cellulose in barley malt by cellulase. Furtherly, laccase and cellulase should have a mutual inhibition when they are pretreated simultaneously.

Airflow Synergistic Needleless Electrospinning of Instant Noodle-like Curly Nanofibrous Membranes for High-Efficiency Air Filtration.

Particulate matter (PM) pollution has become a serious environmental concern. Nanofibrous filters are widely reported to remove PM from polluted air. Herein, efficient and lightweight PM air filters are presented using airflow synergistic needleless electrospinning composed of auxiliary fields such as an airflow field and a secondary inductive electric field. Compared to needleless electrospinning with other spinnerets, it significantly improves productivity, fiber diameter, and porosity of fibrous air filters. The instant noodle-like nanofiber structure can also be controlled by adjusting the airflow velocity. These air filters exhibit high (2.5 µm particulate matter) PM2.5 removal efficiency (99.9%) and high (0.3 µm particulate matter) PM0.3 removal efficiency (99.1%), low pressure drop (56 Pa for PM2.5 and 78 Pa for PM0.3 ), and large dust holding capacitance (the maximum value is 168 g m-2 for PM2.5 , while 102 g m-2 for PM0.3 ). Meanwhile, the proposed PM filters are also tested suitable and stable to other polluted air filtrations such as cigarette smoke and sawdust. The large-scale synthesis of such an attractive nanofiber structure presents the great potential of high-performance filtration/separation materials.

Electrochemical process of early-stage corrosion detection based on N-doped carbon dots with superior Fe3+ responsiveness.

Iron corrosion is a subject of great technological importance and extensive public concern. However, the highly efficient detection of iron corrosion at early stage is still a challenging task. Herein, bright fluorescent carbon dots (CDs) with superior response to Fe3+ were prepared by simple solvothermal process based on citric acid and ammonia. The obtained CDs are able to rapidly, sensitively and selectively respond to Fe3+. The quantitative analysis showed that the CDs exhibited a linear response to Fe3+ in the range of 10 to 300 µM, with a detection limit of 0.9 µM. And the fluorescence quenching of CDs was obvious enough to be detected by the naked eyes. Such promising responsiveness of CDs offers a great opportunity for real-time and visual detection of Fe3+ during electrochemical corrosion process. In addition, due to the excellent stability and solubility of CDs, patterned papers and hydrogels have been fabricated utilizing cellulose and PVA as matrices. The as-prepared biocompatible, environmental-friendly and disposable CDs based fluorescent materials were successfully used for detecting the degree of iron corrosion. This could provide a simple and visual strategy for monitoring the safety of structural metal materials.

Biomimetic scaffolds with programmable pore structures for minimum invasive bone repair.

Due to the complexity of surgery for large-area bone injuries, implanting a large volume of materials into the injury site remains a big challenge in orthopedics. To solve this difficulty, in this study, a series of biomimetic hydroxyapatite/shape-memory composite scaffolds were designed and synthesized with programmable pore structures, based on poly(ε-caprolactone) (PCL), polytetrahydrofuran (PTMG) and the osteoconductive hydroxyapatite (HA). The obtained scaffolds presented various pore structures, high connectivity, tunable mechanical properties, and excellent shape memory performance. Moreover, the mineralization activity of the developed scaffolds could enhance the formation of hydroxyapatite and they showed good biocompatibility in vitro. The in vivo experiments show that scaffolds could promote the formation of new bone in critical size cranial defects. The programmable porous scaffold biomaterials exhibited potential application promise in bone regeneration.

Ionic Transport and Robust Switching Properties of the Confined Self-Assembled Block Copolymer/Homopolymer in Asymmetric Nanochannels.

The self-assembly of block copolymers in a confined space has been proven to be a facile and robust strategy for fabricating assembled structures with various potential applications. Herein, we employed a new pH-responsive polymer self-assembly method to regulate ion transport inside artificial nanochannels. The track-etched asymmetric nanochannels were functionalized with PS22k-b-P4VP17k/hPS4k blend polymers, and the ionic conductance and rectification properties of the proposed system were investigated. The pH-actuated changes in the surface charge and wettability resulted in the selective pH-gated ionic transport behavior. The designed system showed a good switching property to the pH stimulus and could recover during the repetitive experiments. The gating ability of the polymer-nanochannel system increased with increasing the weight of the homopolymer, and the proposed platform demonstrated robust stability and reusability. Numerical and the dissipative particle dynamics simulations were implemented to emulate the pH-dependent self-assembling behavior of diblock copolymers in a confined space, which were consistent with the experimental observations. As an example of the self-assembly of polymers in nanoconfinements, this work provides a facile and robust strategy for the regulation of ion transport in synthetic nanochannels. Meanwhile, this work can be further extended to design artificial smart nanogates for various applications such as mass delivery and energy harvesting.

Rapid screening and isolation of antioxidants from Eupatorium lindleyanum DC. using CCC target-guided by on-line HPLC-DPPH assay.

Counter-current chromatography (CCC) target-guided by on-line HPLC with post-column DPPH assay was established for efficient screening and isolation of large amount of antioxidants from Eupatorium lindleyanum DC. On-line HPLC with post-column DPPH reaction was used to screen the antioxidants and optimize the biphasic solvent system of CCC, then the targeted peaks were purified using CCC. In the present study, three compounds, nepetin, cirsiliol and jaceosidin, were targeted and successively separated from n-butanol fraction of E. lindleyanum DC. by this strategy. All three compounds showed strong DPPH radical scavenging activity. These results confirmed that the strategy would be an efficient and effective method to isolate antioxidants from complex mixtures.

Two new triterpenoid saponins derived from the leaves of Panax ginseng and their antiinflammatory activity.

BACKGROUND: The leaves and roots of Panax ginseng are rich in ginsenosides. However, the chemical compositions of the leaves and roots of P. ginseng differ, resulting in different medicinal functions. In recent years, the aerial parts of members of the Panax genus have received great attention from natural product chemists as producers of bioactive ginsenosides. The aim of this study was the isolation and structural elucidation of novel, minor ginsenosides in the leaves of P. ginseng and evaluation of their antiinflammatory activity in vitro. METHODS: Various chromatographic techniques were applied to obtain pure individual compounds, and their structures were determined by nuclear magnetic resonance and high-resolution mass spectrometry, as well as chemical methods. The antiinflammatory effect of the new compounds was evaluated on lipopolysaccharide-stimulated RAW 264.7 cells. RESULTS AND CONCLUSIONS: Two novel, minor triterpenoid saponins, ginsenoside LS1 (1) and 5,6-didehydroginsenoside Rg3 (2), were isolated from the leaves of P. ginseng. The isolated compounds 1 and 2 were assayed for their inhibitory effect on nitric oxide production in LPS-stimulated RAW 264.7 cells, and Compound 2 showed a significant inhibitory effect with IC50 of 37.38 µM compared with that of NG-monomethyl-L-arginine (IC50 = 90.76 µM). Moreover, Compound 2 significantly decreased secretion of cytokines such as prostaglandin E2 and tumor necrosis factor-α. In addition, Compound 2 significantly suppressed protein expression of inducible nitric oxide synthase and cyclooxygenase-2. These results suggested that Compound 2 could be used as a valuable candidate for medicinal use or functional food, and the mechanism is warranted for further exploration.

Motion sensors achieved from a conducting polymer-metal Schottky contact.

Mechanical-to-electrical energy conversion devices show potential applications in the detection of movements. Previous studies on these sensor devices are mainly based on piezoelectricity or triboelectricity, which typically generates AC signals. In this study, a movement sensor that generated DC signals based on a conducting polymer-metal Schottky diode was prepared for the first time. Using the Al|poly(3,4-ethylenedioxythiophene)|Au device as a model, we showed that the sensor device could detect the touch and sliding movements. Both the pressure of the Al electrode touching the PEDOT surface and its sliding speed affected the voltage outputs. The device showed a high response speed of 1.7 s at 39.8 kPa. The modified device can even measure the sliding speed. The DC output allows the use of electrical energy for running other electronic devices. A conducting polymer-metal Schottky contact may be useful for the development of DC output movement sensors.

Xinjiang herbal tea exerts immunomodulatory activity via TLR2/4-mediated MAPK signaling pathways in RAW264.7 cells and prevents cyclophosphamide-induced immunosuppression in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: A multi-herb Chinese medicinal formula consisting of a variety of medicinal and edible materials has long been consumed as a hot drink and immune enhancer for its efficiency to increase disease resistance in Xinjiang, China. However, no fundamental data has been collected associated with traditional consumption. The present work was designed to evaluate the immunostimulatory role of Xinjiang herbal tea (XMT-WE) in RAW 264.7 macrophages and cyclophosphamide (CTX)-induced immunosuppression mice model. MATERIALS AND METHODS: RAW 264.7 cells were treated with various concentrations of XMT-WE. Nitric oxide (NO) levels were determined using Griess reagents, and pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α were investigated with a cytometric bead array kit. The effects on mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and TNF-α were investigated. Furthermore, activation of nuclear factor (NF)-κB and AP-1 mitogen-activated protein kinase (MAPK) signaling pathways was investigated. RESULTS: Pre-treatment with XMT-WE significantly increased secretion of NO, IL-6, and TNF-α. In addition, XMT-WE markedly increased expression of iNOS, COX-2, and TNF-α as well as AP-1 and NF-κB translocation from the cytoplasm into the nucleus, which was associated with an increase of phosphorylated ERK, JNK, and p38 as well as membrane receptors such as toll-like receptor (TLR) 2 and TLR4. Moreover, XMT-WE promoted the secretion of interleukin-2 (IL-2) and interferon-γ (IFN-γ) in cyclophosphamide (CTX)-induced immunosuppressive mice. CONCLUSION: These results indicated that XMT-WE at 50 µg/ml exerts immunomodulatory activity via TLR2/4-mediated MAPK signaling pathways in RAW 264.7 cells. Furthermore, in vivo experiments revealed that XMT-WE at the dose of 50 and 100 mg/kg strongly stimulated inflammatory cytokines.

Electro-aerodynamic field aided needleless electrospinning.

Auxiliary fields have been used to enhance the performance of needle electrospinning. However, much less has been reported on how auxiliary fields affect needleless electrospinning. Herein, we report a novel needleless electrospinning technique that consists of an aerodynamic field and a second electric field. The second electric field is generated by setting two grounded inductive electrodes near the spinneret. The two auxiliary fields have to be applied simultaneously to ensure working of the electrospinning process. A synergistic effect was observed between inductive electrode and airflow. The aerodynamic-electric auxiliary field was found to significantly increase fiber production rate (4.5 g h-1), by 350% in comparison to the setup without auxiliary field (1.0 g h-1), whereas it had little effect on fiber diameter. The auxiliary fields allow running needleless electrospinning at an applied voltage equivalent to that in needle electrospinning (e.g. 10-30 kV). The finite element analyses of electric field and airflow field verify that the inductive electrodes increase electric field strength near the spinneret, and the airflow assists in fiber deposition. This novel needleless electrospinning may be useful for development of high-efficiency, low energy-consumption nanofiber production systems.

Modification of recombinant elastase expressed in Pichia pastoris by introduction of N-glycosylation sites.

A novel N-glycosylation site was introduced into recombinant elastase (rPAE) at N36, N67, or N264 through the site-directed mutagenesis of I38T, A69T, or N266T, respectively. The A69T mutation completely inhibited the expression of rPAE. As expected, the I38T and N266T mutant proteins exhibited higher degrees of N-glycosylation compared with the wild type rPAE. The I38T mutant was more efficient in the hydrolysis of casein in aqueous medium and exhibited higher specific activity and k(cat) values and a lower K(m) value. In contrast, the N266T mutant and the wild type displayed similar values. Importantly, the I38T mutant achieved in higher rates and yields of peptide synthesis in 50% (v/v) dimethylsulfoxide, whereas the N266T mutant was similar to the wild type rPAE. Furthermore, the maximum yield of Z-Ala-Phe-NH2 synthesis catalyzed by the I38T mutant protein (87%) was higher than those achieved by the wild type (78%) and N266T mutant (78%) proteins. Neither the I38T nor the N266T mutation exerted significant effects on the rPAE solvent stability. In aqueous medium, the I38T mutation decreased the rPAE thermostability, and the N266T mutation slightly improved that. In conclusion, the I38T mutation improved the potential of rPAE in industrial applications.

Preparative isolation and purification of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. by high-speed counter-current chromatography.

A high-speed counter-current chromatography (HSCCC) method was established for the preparative separation of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:4:2:3, v/v/v/v) was selected. From 540 mg of the n-butanol fraction of Eupatorium lindleyanum DC., 10.8 mg of 3ß-hydroxy-8ß-[4'-hydroxytigloyloxy]-costunolide, 17.9 mg of eupalinolide A and 19.3 mg of eupalinolide B were obtained in a one-step HSCCC separation, with purities of 91.8%, 97.9% and 97.1%, respectively, as determined by HPLC. Their structures were further identified by ESI-MS and ¹H-NMR.

Antioxidant activities of extracts and fractions from Eupatorium lindleyanum DC.

The antioxidant activities of water extract (WE), ethanol extract (EE), residue water extract (RWE) and petroleum ether (PF), ethyl acetate (EF), n-BuOH (BF) and water (WF) fractions of the ethanol extract from Eupatorium Lindley DC were investigated for the first time. Total phenolics content, DPPH radical scavenging activities, superoxide radical scavenging activities, total reduction capability, and ferrous ions chelating activities were determined for all the extracts and fractions. The results showed that all the extracts and fractions exhibited antioxidant activities with different magnitudes of potency. Among all the samples, WE and RWE exhibited the best antioxidant capacities, the BF also exhibited high antioxidant abilities in all tests except for the metal chelating activity, while the other extracts and fractions were relatively weak antioxidants. The BF had the highest total phenolics contents in all extracts and fractions, and the WE and RWE were found to be rich in tannins. Furthermore, the content of total phenolics showed good correlation with DPPH radical scavenging activity, superoxide anion radical scavenging activity, and the reducing power. Phenolic composition of all the extracts and fractions was identified and quantified by HPLC. The results indicate that the extracts of E. Lindley DC might be a useful potential source of natural antioxidant ingredients.