PLoS One
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2019
·Vol. 14
·期 4
·e0215084
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IF 2.776
Xiaoqin Wang,Zhi-Min Li,Qingyue Li,Mingsong Shi,Lingling Bao,Dingguo Xu,Zhimin Li
Fermentation-respiration switch protein (FrsA) was thought to play an important role in controlling the metabolic flux between respiration and fermentation pathways, whereas the biochemical function of FrsA was unclear yet. A gene coding for FrsA protein from Vibrio vulnificus was chemically synthesized. The recombinant VvFrsA was expressed as a soluble protein and purified by Ni-NTA affinity chromatography. The protein had a subunit molecular weight of ca . 45 kDa by SDS-PAGE and preferred short-chain esters when p-nitrophenyl alkanoate esters were used as substrates. Optimum condition for VvFrsA was found to be at pH 9.0 and 50 °C. The protein retained high esterase activity at alkaline condition and would denature slowly at over 50 °C. With p-nitrophenyl acetate as the substrate, the K m and k cat were determined to be 18.6 mM and 0.67 s -1 , respectively, by steady-state kinetic assay. Molecular dynamics simulation and docking model structure revealed that p-nitrophenyl acetate could be the substrate of VvFrsA. In conclusion our results demonstrated that the protein was able to catalyze the hydrolysis of esters, especially p-nitrophenyl acetate, for the first time.
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Nano Energy
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2019
·
IF 15.548
Jia Li,Kang Liu,Tianpeng Ding,Peihua Yang,Jiangjiang Duan,Jun Zhou
Harvesting environmental thermal energy from a natural evaporation process is a promising method for acquiring renewable and sustainable energy. Here, we present an evaporation-driven water flow nanogenerator based on a piece of flexible carbon nanoparticle film. The open-circuit voltage of one single-piece device can be tuned from − 3 to 3 V by manipulating the surface functional groups on the carbon nanoparticles. The effects of different modification molecules and solution concentrations were also investigated. By combining the modified carbon films with opposite surface charges, we enhanced the output of the generator to a maximum open-circuit voltage of 5 V and a short-circuit current of 1.5 μA with a film size of 5 cm × 5 cm. Furthermore, the device can be easily integrated with carbon nanotube-based supercapacitors (CNT-SCs) to assemble the energy-storing and energy-harvesting devices into a self-sustaining power system . The electrical output of the device can directly power a liquid crystal display in an ambient environment and a blue LED with help of self-charged built-in SCs. This eco-friendly device, with its low cost and simple fabrication, shows great potential for future clean energy utilization and for extending the field of portable electronics.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 9
·4525-4535
·
IF 10.733
Xiaofeng Pan,Qinhua Wang,Runsheng Guo,Yonghao Ni,Kai Liu,Xinhua Ouyang,Lihui Chen,Liulian Huang,Shilin Cao,Mingying Xie
Hydrogel-based strain sensors are promising for skin-like electronics. To satisfy the various requirements of wearable devices used for direct human contact, a hydrogel needs to possess transparent, stretchable, conductive, antifreezing and moisture-retention properties. However, preparation of hydrogels with these properties is challenging. Herein, we innovatively designed and fabricated a transparent, conductive polyvinyl alcohol-tannic acid@talc (PVA-TA@talc) organohydrogel via molecular-level ion conductive channels in ethylene glycol/H2O (EG/H2O), and this organohydrogel integrates excellent conductive, transparent, antifreezing, moisture-retention, toughness, and stretchable properties for the first time. Moreover, this organohydrogel possesses remarkable light filtering capabilities and can effectively filter ultraviolet (UV) light. Interestingly, this organohydrogel can act as a wearable dressing to protect skin from frostbite and ultraviolet radiation. Notably, based on molecular-level ion transport channels, this organohydrogel has great strain sensitivity (gauge factor ≈ 9.17, 0–1.2% strain) that enables recognition of limb movement, pulse, language, and handwriting. The organohydrogel can collect electromyography (EMG) signals as a bioelectrode and be applied to prepare a T-pen for controlling smartphones. In short, this novel organohydrogel has great application prospects for wearable electronics, and the strategy for the organohydrogel constructed via molecular-level ion conductive channels will open a new route for the preparation of multifunctional ionic organohydrogels.
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ENVIRONMENTAL POLLUTION
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2019
·
IF 5.714
Xiaoxin Han,Xueqiang Lu,Rolf D. Vogt
Microplastic pollution in the environment has received growing attention worldwide. A major impediment for accurate measurements of microplastics in environmental matrixes is to extract the particles. The most commonly-used method for separation from soil or sediment is flotation in dense liquid based on the relatively low density of plastic particles. This study provides an improved and optimized process for extraction of microplastic particles by modifying the floatation technique and floatation solution. Microplastics in soils and sediments are extracted by adding 200 g dry soil or sediment sample to 1.3 L mix of the saturated NaCl and NaI solutions in a volume ratio of 1:1 and aerating for 40 s then filtering the supernatant. The accuracy and precision of the new approach is validated by recovery experiments using soil and sediment samples spiked with six common microplastic compounds: polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and expanded polystyrene (EPS), and comparison with the previous method. The optimized approach is further compared with the previous approach using the real soil and sediment samples.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Deyou Yu,Lubiao Li,Minghua Wu,John C. Crittenden
The photocatalytic activity of metal-organic frameworks (MOFs) is drawing great attention in the field of environmental remediation. However, the efficiency of MOFs still remains low because of the rapid recombination of valence band holes and conduction band electrons (a.k.a., charge carriers). The combination of photocatalysis and electron acceptors such as ozone are believed to be an efficient strategy to reduce the charge carrier recombination. Herein, we report that photocatalytic ozonation (PCO) using an Fe-based MOF (MIL-88A(Fe)) has greater destruction than photocatalysis and/or catalytic ozonation in terms of 4-nitrophenol (4-NP) degradation and mineralization. It is worth noting that our Fe-based MOF has a large number of Lewis acid sites (LAS). The pseudo-first order kinetic rate constants ( k ) of 4-NP degradation using PCO, photocatalysis and catalytic ozonation systems are 0.1632, 0.0143 and 0.0840 min −1 , respectively. The TOC removal of 4-NP in the PCO system is approximately 75.4% ([4-NP] = 100 ppm, ozone input dosage = 1.5 mg/min-L, UV light intensity = 3.46 × 10 -6 Einstiens/L-s, treatment time = 30 min) and this is much greater than those of photocatalysis (17.6%) and catalytic ozonation (38.7%). Most importantly, both the k value and TOC removal in the PCO system are much higher than the sum of those in other two processes, implying a strong synergistic effect in the PCO process. Mechanistic studies were conducted using electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) measurements and demonstrate that the synergistic effect may originate from the enhanced photoinduced carrier separation using ozone as an electron acceptor. Furthermore, OH, O 2 − , and 1 O 2 are found to be the principal reactive oxygen species (ROS) for 4-NP degradation and mineralization. Integrating the analysis of band structure, EPR and scavenging experiment results, ozone is not only able to reduce charge carrier recombination but also can be catalytically decomposed to generate more ROS on the LAS of MIL-88A(Fe). This study provides deep insights into the use of MOFs as effective advanced oxidation processes (AOPs).
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Nature Communications
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2019
·Vol. 10
·期 1
·1-11
·
IF 11.878
Yang Lu,Ma Zaijun,Wang Han,Niu Kongyan,Cao Ye,Sun Le,Geng Yang,Yang Bo,Gao Feng,Chen Zuolong,Wu Zhen,Li Qingqing,Shen Yong,Zhang Xumin,Jiang Hong,Chen Yelin,Liu Rui,Liu Nan,Zhang Yaoyang
The long-lived proteome constitutes a pool of exceptionally stable proteins with limited turnover. Previous studies on ubiquitin-mediated protein degradation primarily focused on relatively short-lived proteins; how ubiquitylation modifies the long-lived proteome and its regulatory effect on adult lifespan is unclear. Here we profile the age-dependent dynamics of long-lived proteomes in Drosophila by mass spectrometry using stable isotope switching coupled with antibody-enriched ubiquitylome analysis. Our data describe landscapes of long-lived proteins in somatic and reproductive tissues of Drosophila during adult lifespan, and reveal a preferential ubiquitylation of older long-lived proteins. We identify an age-modulated increase of ubiquitylation on long-lived histone 2A protein in Drosophila , which is evolutionarily conserved in mouse, monkey, and human. A reduction of ubiquitylated histone 2A in mutant flies is associated with longevity and healthy lifespan. Together, our data reveal an evolutionarily conserved biomarker of aging that links epigenetic modulation of the long-lived histone protein to lifespan.
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BIOMACROMOLECULES
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2019
·
IF 5.667
Jihong Wang,Dongdong Li,Wei Tao,Yang Lu,Xianzhu Yang,Jun Wang
In this work, novel amphiphilic diblock copolymers of polyethylene glycol and polyphosphoester with pendant thioether groups, denoted as mPEG-b-PMSPEP, were synthesized through the ring-opening polymerization of functionalized cyclic phosphoester monomer using methoxy poly(ethylene glycol) and Sn(Oct)2 as the macroinitiator and catalyst, respectively. The successful synthesis was confirmed by 1H, 13C, 31P nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). These amphiphilic block copolymers self-assembled spontaneously in the aqueous solution, and the formed nanoparticles were sensitive to the oxidation that induced the hydrophobic to hydrophilic transition for its PMSPEP core under triggering of H2O2 and the subsequent dissociation of the nanoparticles. In addition, the reactive oxygen species (ROS) generated by light and the photosensitizer were also capable of carrying out the oxidation of these nanoparticles. Their oxidation profiles were systemically evaluated by 1H NMR. Finally, the mPEG-b-PMSPEP nanoparticles were used to coencapsulate the photosensitizer chlorin e6 (Ce6) and anticancer drug paclitaxel (PTX), achieving the photoaccelerated PTX release via oxidation of the nanoparticles by the generated ROS under light irradiation. Meanwhile, the in vitro cytotoxicity assays indicated that these nanoparticles coencapsulated with PTX and Ce6 showed a combined cell-killing effect toward MDA-MB-231 tumor cells, exhibiting great potential for drug delivery systems that realize the synergistic chemo-photodynamic therapy for cancer treatment.
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MATERIALS AND STRUCTURES
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2019
·Vol. 52
·期 4
·1-11
·
IF 2.548
Si Jingjing,Li Yang,Yu Xin
Cold-mixed epoxy asphalt (CEA) is an eco-friendly material for steel bridge deck pavements. The effects of the asphalt on the curing behavior and mechanical properties of the CEA were studied. The pot life, curing characteristics, and curing kinetics of CEA blends were investigated by rotational viscosity testing, dynamic shear rheological analysis, and fluorescence microscopy. The results showed that the CEA pot life increased with asphalt content, and the curing apparent activation energy \( E_{k} \) of CEA-0.4 was more than two times higher than that of the epoxy resin. The curing reaction between the epoxy resin and curing agent was hindered by the asphalt. According to the FTIR and DSC results, the curing degree of the CEAs decreased with asphalt content. The elongation at break of the CEAs increased, while the tensile and adhesion strength decreased with asphalt content.
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Journal of Materials Chemistry B
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2019
·Vol. 7
·期 22
·3576-3581
·
IF 5.047
Xianqi Feng,Jun Xu,Yanxia Liu,Wenpeng Zhao
In this study, a novel and facile glucose detection system based on inverse opal hydrogels (IOHGs) was developed. Based on the intuitive structural colour, the gel sensors could be used for the detection of carbohydrates containing 1,2-cis-diol groups and diagnosis of diabetes without the assistance of sophisticated analysis instruments. Compared to the case of traditional opal sensors, the stable network structure of the IOHG samples endowed them with reusability for multiple times, which could suffer 10 cyclic detections without any reduction in sensitivity; possessing the combined advantages of high sensitivity, a stable network, and easy processing, IOHGs might open up a new avenue and propose a promising prospect in the detection and identification of diverse organic compounds.
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RSC Advances
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2019
·Vol. 9
·期 22
·12667-12674
·
IF 3.049
Mo Zhu,Ying Hao,Xun Ma,Lin Feng,Yuanxin Zhai,Yaping Ding,Guosheng Cheng
A new class of stimuli responsive drug delivery systems is emerging to establish new paradigms for enhancing therapeutic efficacy. To date, most electro-responsive systems rely on noble metal electrodes that likely cause the limitations for implantation applications. Herein, a graphene/polypyrrole composite electrode (GN–PPy–FL) was fabricated based on two-dimensional (2D) graphene (GN) film and conductive and biocompatible polypyrrole (PPy) nanoparticles loaded with a negative drug model of fluorescein sodium (FL) via chemical oxidation polymerization. The conductive composite electrode was utilized as a drug carrier to realize the electrically controlled release of the FL. The release rate from conductive nanoparticles can be controlled by the applied voltages. The study provides a multi-stimuli responsive drug release system, demonstrating the potential applications of the controlled release of various drugs, peptides or proteins.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 19
·12333-12342
·
IF 10.733
Guomin Ding,Weicheng Jiao,Rongguo Wang,Zhenming Chu,Yifan Huang
Multifunctional surfaces with special wettability and sensing capabilities have attracted the interest of researchers because of their wide application prospects. Herein, based on octadecylamine (ODA) and carboxylic carbon nanotubes (cCNTs), a conductive composite coating (ODA/cCNT) with a micro–nanoscale hierarchical structure is fabricated by a simple one-step method. The wettability of ODA/cCNT can be controlled, ranging from strong hydrophilicity to superhydrophobicity, by changing the content of ODA, and the adhesive force of the superhydrophobic coating is adjustable over a large range, spanning from 71.4 μN to 30.9 μN. Using the ODA/cCNTs with adjustable adhesion behavior, the lossless transportation of water microdroplets has been achieved. Furthermore, due to its conductivity and special microstructure, the superhydrophobic ODA/cCNT can sense bending deformation via changing resistance and shows a higher sensitivity than other coatings. More importantly, by means of the strong water repellence and the gas sensing property of cCNTs, we report for the first time an underwater, self-sensing, superhydrophobic material with enhanced sensitivity. The change degree of its resistance in water is more than twice as large as that in air for the same deformation. The water level can also be detected by the superhydrophobic coating due to its unique underwater state. Therefore, the multifunctional ODA/cCNT can be an excellent candidate for the fabrication of underwater smart devices.
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CHEMISTRY OF MATERIALS
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2019
·
IF 10.159
Shanshan Zeng,Fucong Lyu,Ligang Sun,Yawen Zhan,Fei-Xiang Ma,Jian Lu,Yang Yang Li
In this work, UiO-66-based metal–organic frameworks are investigated as an oxygen reduction reaction (ORR) catalyst for the first time. UiO-66-NO2 is solvothermally grown on the surface of cobalt phthalocyanine-anchored carbon nanotube (CoCNT) surface, serving as an oxygen “pump” to accelerate the oxygen reduction reaction (ORR). The UiO-66-NO2-attached CoCNT (UiO-66-NO2@CoCNT) exhibits superior electrochemical catalytic properties, exceeding the state-of-the-art commercial 20% Pt/C catalyst with more positive half-wave potential (15 mV difference, at 1600 rpm), better stability (no significant degradation for UiO-66-NO2@CoCNT vs 19% degradation for 20% Pt/C after 25 000 s), and higher methanol tolerance. When assembled in a flexible zinc–air battery, the UiO-66-NO2@CoCNT remains a competitive alternative to commercial 20% Pt/C catalyst with comparable power density and excellent flexibility, suggesting its potential in wearable electronic devices. The outstanding performance of UiO-66-NO2@CoCNT composite is closely related to the synergetic effect among the three components: CNT as a conductive backbone, cobalt phthalocyanines as the oxygen reduction catalytic active site, and UiO-66-NO2 as an ideal oxygen adsorption pump (the oxygen diffusion rate is 4.8 times that of 20% Pt/C and 17.7 times that of CoCNT). The synergy between the three components facilitates oxygen adsorption, transfer of adsorbed oxygen molecules, oxygen reduction, and electron conduction.
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