JOURNAL OF BIOMATERIALS APPLICATIONS
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2022
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IF 2.712
Shuang Yang,Linhao Lan,Mingda Gong,Ke Yang,Xiaoming Li
An effective dressing is essential for wound healing. In fact, the wettability performance is one of the most important factors of a wound dressing. The fundamental functions of a wound dressing involve the absorption of excess exudates and maintenance of optimal moisture at the wound by controlling water evaporation. Here, we designed a type of chitosan (CS) sponge and PCL nanofibrous membrane composite dressing with asymmetric wettability surfaces as wound healing materials for biomedical applications. The hydrophobic surfaces of the composite dressing were waterproof and could efficiently control the water vapor transmission rate, whereas the hydrophilic surface of the CS sponge had good cytocompatibility and water-absorbing capability. Insulin-like growth factor-2 (IGF-2) was added to the CS sponge, and exhibited a stimulatory effect on fibroblasts migration and proliferation. Therefore, the fabricated CS sponge and PCL membrane composite dressing had excellent cytocompatibility, vapor transmission rate, and liquid absorption and asymmetric wettability, suggesting its potential as a promising alternative to traditional wound dressing.
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JOURNAL OF BIOTECHNOLOGY
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2022
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IF 3.595
Feng Cheng,Wei-Bang Xie,Xiao-Fan Gao,Rong-Liang Chu,Shen-Yuan Xu,Ya-Jun Wang,Yu-Guo Zheng
( S )-2-chlorophenylglycine (( S )-CPG) is a key chiral intermediate for the synthesis of clopidogrel . Herein, a novel, efficient and environmentally friendly chemo-enzymatic route for the preparation of optically pure ( S )-CPG was developed. A straightforward chemical synthesis of the corresponding prochiral keto acid substrate (2-chlorophenyl)glyoxylic acid (CPGA) was developed with 91.7% yield, which was enantioselectively aminated by leucine dehydrogenase (LeuDH) to ( S )-CPG. Moreover, protein engineering of LeuDH was performed via directed evolution and semi-rational design. A beneficial variant Es LeuDH-F362L with enlarged substrate-binding pocket and increased hydrogen bond between K77 and substrate CPGA was constructed, which exhibited 2.1-fold enhanced specific activity but decreased thermal stability . Coupled with a glucose dehydrogenase from Bacillus megaterium ( Bm GDH) for NADH regeneration, Es LeuDH-F362L completely converted up to 0.5 M CPGA to ( S )-CPG in 8 h at 40 °C.
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Environmental Science-Nano
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2022
·Vol. 9
·期 9
·3407-3416
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IF 9.473
Han Song,Xinwen Ou,Mengye Wang,Yan Zhang,Zhang Lin
H2 production during the transformation of Fe(OH)2 into magnetite (i.e., Schikorr reaction), has a significant impact on many environmental applications, including the long-term effectiveness of permeable reactive barriers composed of zerovalent iron and the stability of geological radioactive waste repository. However, the reactivity of the Schikorr reaction is not systematically evaluated and its chemical mechanism still remains controversial. Here, we investigate water reduction on the Fe(OH)2 surfaces with the help of an interface-reaction model between water and Fe(OH)2. The Fe(OH)2 hexagonal nanosheets prepared using a coprecipitation method possess dominantly exposed (001) and (100) facets. As unveiled by the DFT simulations, the (001) Fe(OH)2 facet only exposes OH, which is, therefore, inert to water reduction. Moreover, the active Fe-exposed (100) Fe(OH)2 facet is more thermodynamically favourable for water adsorption and dissociation than the (101) and (102) facets. However, the high energy barrier for water dissociation (2.79 eV) may restrict the rate of water reduction on the Fe(OH)2 facet. In addition, the capacity of (100), (101), and (102) Fe(OH)2 facets to adsorb OH− is stronger than that for H2O, which further inhibits water reduction. Furthermore, DOS calculations manifest that Fe d orbitals play a significant role in H2O adsorption, indicating that manipulating the electronic structure of the Fe site is a critical path to mediate water reduction in Fe(OH)2. Our study provides new insights into the understanding of the mechanism of the phase transformation of Fe(OH)2 under anaerobic conditions in environmental and earth sciences.
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Electrocatalysis
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2022
·Vol. 13
·期 6
·818-829
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IF 2.933
Dong Zhichen,Wu Jian,Guo Xingjia
In this work, we prepared cubic nickel oxide (NiO) nanosheets and constructed NiO with oxygen defects induced by halogen Cl ions (NiO-Vo1). Cubic nickel oxide nanosheets were used as catalysts for electrocatalytic oxygen evolution reaction (OER) and oxidation of chiral 2-butanol. Under artificial simulated sunlight, NiO-Vo1 exhibited good photo-electrocatalytic OER activity and catalytic stability. The high catalytic activity is mainly attributed to the activation of nickel active sites by the halide ion-induced oxygen defect and the enhancement of photoinduced electron–hole separation efficiency. Furthermore, the electrocatalytic performance of oxygen-deficient nickel oxide for the oxidation of chiral 2-butanol was investigated. The results show the catalytic activity of NiO-Vo1 for electrocatalytic oxidation of 2-butanol to butanone compared with NiO. Interestingly, there is no significant difference in the electrocatalytic activity of NiO for (R)-(-)-2-butanol and (S)-( +)-2-butanol oxidation. When NiO-Vo1 was used as the catalyst, the catalytic oxidation reaction rate of (R)-(-)-2-butanol alcohol was significantly higher than that of (S)-( +)-2-butanol alcohol. At 1.77 V vs RHE voltage, the (R)-(-)-2-butanol alcohol has obvious oxidation reaction while the (S)-( +)-2-butanol alcohol is almost absent, realizing the selective electrocatalytic oxidation of (R)-(-)-2-butanol alcohol. This may be attributed to the difference in the interaction strength of chiral molecules with the surface defects of NiO after applying a voltage during the catalytic process, resulting in different catalytic activities. Here, our proposed strategy through the synergistic effect of applied voltage and surface defects provides a new approach for chiral molecule synthesis and efficient chiral resolution. The halide ion-induced defect-catalyst provides a new strategy for the preparation of efficient electrocatalytic water splitting OER and alcohol-selective oxidation catalysts. Graphical Abstract
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ACS ES&T Water
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2022
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IF 0
Fan Yang,Jianwei Yu,Qi Wang,Chunmiao Wang,Yuning Du,Zhiyuan Liu,Lili Zhang,Zhengang Liu,Chuanyong Jing,Junwang Tang,Min Yang
Powdered activated carbon (PAC) is the most widely used adsorbent for removing odorants like 2-methylisoborneol (MIB) for drinking water purification. The hydrophobicity exhibited by the moieties of the carbon structure is known to be important for the adsorption of activated carbon. Here we propose a novel approach for regulating the hydrophobicity of the carbon surface by rearranging carbon atoms without changing the pore structures markedly through thermal transformation using Fe(NO3)3 as the catalyst. Five different PACs were transformed into hydrophobic porous carbons (HPCs) with 2.47–3.00 times the adsorption capacity and faster adsorption rates, accompanied by the surface free energy being decreased by 26.67–36.40%, the IG2/IG1 representing the degree of order being increased by 17.31–53.68%, the C–C(sp2)/C–C(sp3) being increased by 31.9–49.8%, and the oxygen content being decreased by 4.71–8.63%. The increase in ordered planar crystals dominated by sp2 carbons as well as the decrease in the number of heteroatoms in HPCs might be the main reason for its enhanced adsorption of MIB. Simulation based on reactive force field molecular dynamics indicated that MIB molecules tended to be adsorbed in ordered structures. This study provides a novel angle for improving the surface hydrophobicity of activated carbon, which may lead to the development of high-performance adsorbents.
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JOURNAL OF ELECTRONIC MATERIALS
·
2021
·Vol. 50
·期 11
·6228-6236
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IF 1.938
Liang Yue,Weng Ling,Zhang Wenlong
Polypropylene (PP) is considered a promising material for eco-friendly high-voltage direct current (HVDC) cable insulation. However, PP is prone to space charge accumulation under direct current (DC) electric stress, which limits its applications. In this study, 4-allyloxy-2-hydroxybenzophenone (AHB) with polar functional groups and a conjugated structure was grafted onto PP via melt grafting to improve its electrical properties. The effects of several reaction variables, specifically initiator and monomer content, reaction temperature, rotor speed, and grafting yield time were studied, and the optimal grafting conditions were determined. Evidence of grafting was examined by Fourier transform infrared (FTIR) spectroscopy. Moreover, the space charge characteristics, volume resistivity, and DC breakdown strength of the grafted PP were also studied. The FTIR results demonstrated that the AHB monomer was successfully grafted onto PP, and the maximum grafting yield obtained under the optimal grafting conditions was 0.94%. Furthermore, when the grafting yield was 0.73%, the grafted PP effectively inhibited space charge accumulation and exhibited the highest volume resistivity and DC breakdown strength. Thus, this work provides useful ideas for the design and development of environmentally friendly polymer insulating materials for HVDC applications.
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JOURNAL OF SOLID STATE CHEMISTRY
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2021
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IF 3.498
Zhengdi Jiang,Zhen Li,Zhenyu Chen,Xuanrui Zhang,Weijie Fan,Yuan Liu,Hui Dan,Yi Ding,Tao Duan
Zircon (ZrSiO 4 ) ceramics were widely used in the field of nuclear waste immobilization because of their excellent properties. However, the SiO 2 /ZrSiO 4 ceramics were usually obtained in the preparation of ZrSiO 4 . The actinides immobilization behavior of SiO 2 /ZrSiO 4 ceramics is unclear. Herein, Nd-doped 0.2SiO 2 /Zr 1- x Nd x SiO 4- x /2 (0≤ x ≤ 0.1) ceramics were fabricated and the effects of Nd-doping and sintering temperature on their phase and microstructure evolution were investigated. The obtained ceramics were characterized by XRD , SEM, BSE and EDS . Results show that 0.2SiO 2 /Zr 1- x Nd x SiO 4- x /2 ceramics with 0≤ x < 0.04 are ZrSiO 4 phase; while with 0.04≤ x ≤ 0.1 are coexistence of ZrSiO 4 and Nd 2 Si 2 O 7 phases. The solubility limit of Nd 3+ in 0.2SiO 2 /ZrSiO 4 is about 4 at%. The lattice volume of ZrSiO 4 increased with increasing Nd-doped content and sintering temperature. Furthermore, higher Nd-doped content and sintering temperature are beneficial to the densification of the obtained ceramics. The results demonstrate that the 0.2SiO 2 /ZrSiO 4 ceramics can be employed as waste form materials to immobilize trivalent actinides.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2021
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IF 5.279
Feifei Hou,Dexin Feng,Mo Xian,Wei Huang
2-Acetamidophenol (AAP) is an aromatic product with promising activities in agricultural applications and medical research. At present, AAP is synthesized by chemical methods from nonrenewable fossil fuel resources, which cause environmental pollution and the reaction conditions are harsh. In this study, we constructed the artificial biosynthetic pathway of AAP with five different expressed proteins in Escherichia coli for the first time. By introducing the hydrogen peroxide degrading enzyme catalase and improving cell tolerance to toxic intermediates or products, the yield of AAP reached 33.54 mg/L using shaking-flask culture. The best-engineered strain could produce 568.57 mg/L AAP by fed-batch fermentation from glucose and precursor (2-aminophenol, 2-AP) addition. Furthermore, a one-pot whole-cell cascade biocatalytic pathway to AAP and analogues was developed and optimized. This method can efficiently produce 1.8 g/L AAP using the methyl anthranilate hydrolysis product as the substrate. This study provides not only the de novo artificial biosynthetic pathway of AAP in E. coli but also a promising sustainable and efficient strategy to enable the synthesis of AAP on a gram scale.
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Materials Today Chemistry
·
2021
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IF 8.301
X. Jiao,H. Li,X. Cheng
This article deals with three cellulose-based fluorescent macromolecular sensors by introducing 1,8-naphthalimide fluorophore to cellulose . First, through the etherification reaction of cellulose with BrCH 2 CH 2 NH 2 , –NH 2 group–bearing cellulose CS 1 was obtained. Then, the –NH 2 group reacts with 4-bromo-1,8-naphthalic anhydride to synthesize a naphthalimide cellulose derivative ( CS 2 ). Finally, the recognition group was introduced by substituting Br atoms, and three cellulose fluorescent probes ( CS 3 , CS 4 , and CS 5 ) were obtained eventually. Structure and fluorescence properties of the macromolecular sensors were characterized and confirmed. Fluorescence detection measurements show that these probes can be used as selective and sensitive fluorescent sensors to 2,4,6-trinitrophenol (TNP). The detection limits are 0.52 μM, 0.76 μM, and 0.81 μM, indicating good detection performance. This work provides a new method for the selective detection of TNP and also a method to enlarge the application scope of cellulose.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Songmei Li,Yimin Yu,Xiaoyan Sun,Xifeng Ding,Huafang Yang,Shibing Pan,Lixi Wang,Qitu Zhang
Ni(OH) 2 has been acknowledged as a promising oxygen evolution reaction (OER) electrocatalyst owing to its good electrochemical activity and low cost. However, application of the pristine Ni(OH) 2 is limited by the poor conductivity and low exposure of the active sites. Herein, a [email protected] (OH) 2 composite is prepared through a hydrothermal reaction. Heat treatment temperature proves to have a great influence on the electrocatalytic activity. In 0.1 M KOH electrolyte, the composite treated at 175 °C shows an overpotential of only 287 mV to reach the current density of 10 mA·cm −2 . Besides, the low Tafel slope (42 mV·dec −1 ) and superior stability (15 h at 10 mA·cm −2 ) also confirm the composite as an excellent OER electrocatalyst. The brilliant activity and stability toward OER can be attributed to the promoted coupling between Ni and Fe centers and the improved conductivity due to the 2D 18 p-electrons ring conjugate structure of hemin. Besides, effective hydrogen bonds between Ni(OH) 2 and hemin hinder the aggregation of Ni(OH) 2 , which ensures the catalyst enormous accessible active sites. This work offers a new method for the modification of Ni(OH) 2 as OER electrocatalysts. And the application of hemin also serves as a successful case for the use of biomass materials in OER electrocatalysis .
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Qun Liu,Kun Xu,Guangxu Hu,Fanming Zeng,Xiao Li,Chun Li,Yu Zhang
MIL-101(Cr)/polyacrylamide/chitosan (named as MIL-101(Cr)/PAM/CSA) composite aerogel with large surface area is synthesized by incorporating MIL-101(Cr) into polyacrylamide/chitosan composite aerogel and used for efficient 2, 4-Dichlorophenoxyacetic acid adsorption. MIL-101(Cr)/PAM/CSA and polyacrylamide/chitosan composite aerogels exhibit good underwater superelastic properties with multi-level network synergistic cross-linking. After introducing MIL-101(Cr) with the mass loading of 30%, the specific surface area of the composite aerogels enlarge from 58.15 m 2 g −1 to 310.94 m 2 g −1 . MIL-101(Cr)/PAM/CSA exhibits high adsorption capacity of 302.45 mg g −1 for 2, 4-Dichlorophenoxyacetic acid (2, 4-D) and stable recycling capability. This work provides a general and effective method to synthesize composite aerogel with underwater superelastic properties, hierarchical pores and large surface area, promising to realize regeneration after compression with reduced solvent usage and costs.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
·
IF 6.953
Huashan Gao,Linlin Ding,Rui Liu,Xinhua Zheng,Xichao Xia,Fuan Wang,Jinxu Qi,Weishuang Tong,Yuanhao Qiu
Anoectochilus roxburghii is a traditional herb in China that can be potentially used to treat diabetes. A novel polysaccharide ARLP-W was isolated from Anoectochilus roxburghii by chromatography on DEAE-52 cellulose. Chemical analysis indicated that ARLP-W (8.1 × 10 4 Da) was mainly composed of mannose and glucose. The main linkages of glycosidic bonds of ARLP-W were β-1, 4-Manp and α-1, 4-Glcp. The terminal Glcp was connected to Manp-via O-3. RT-qPCR and western blotting analysis showed that ARLP-W caused a significant reduction in the levels of the key gluconeogenesis enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase) in the liver. The results of the insulin resistance tests indicated that ARLP-W increased glucose absorption. These results indicate that ARLP-W has a good therapeutic effect on type 2 diabetes and can assist with further development and application treatment of diabetes.
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