Frontiers of Chemical Science and Engineering
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2020
·Vol. 14
·期 6
·956-966
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IF 3.552
Ni Qingzhuo,Cheng Hao,Ma Jianfeng,Kong Yong,Komarneni Sridhar
A ZnMn 2 O 4 catalyst has been synthesized via a sucrose-aided combustion method and characterized by various analytical techniques. It is composed of numerous nanoparticles (15–110 nm) assembled into a porous structure with a specific surface area (SSA) of 19.1 m 2 ·g −1 . Its catalytic activity has been investigated for the degradation of orange II dye using three different systems, i.e., the photocatalysis system with visible light, the chemocatalysis system with bisulfite, and the photochemical catalysis system with both visible light and bisulfite. The last system exhibits the maximum degradation efficiency of 90%, much higher than the photocatalysis system (15%) and the chemocatalysis system (67%). The recycling experiments indicate that the ZnMn 2 O 4 catalyst has high stability and reusability and is thus a green and eximious catalyst. Furthermore, the potential degradation mechanisms applicable to the three systems are discussed with relevant theoretical analysis and scavenging experiments for radicals. The active species such as Mn(III), O 2 •− , h + , e aq − , SO 4 •− and HO • are proposed to be responsible for the excellent degradation results in the photo-chemical catalysis system with the ZnMn 2 O 4 catalyst.
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CHEMICAL PAPERS
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2020
·Vol. 74
·期 9
·2875-2882
·
IF 1.68
Gong Yilu,Shao Tantan,Chen Xiaolong,Cao Shusen,Chen Lijun
The silicone modified acrylate dispersion was successfully prepared by semi-continuous seed emulsion polymerization, in which methyl methacrylate (MMA) was used as a hard monomer, butyl methacrylate (BA)was used as a soft monomer, and a double bond-containing polymerizable emulsifier ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86)and potassium persulfate (KPS)were utilized as emulsifiers and initiators, respectively. A functional monomer, benzyl methacrylate (BZMA), and a modified monomer, vinyltriethoxysilane (VTES), were introduced into the base dispersion. The factors, which have an influence on emulsion polymerization performance, were optimized. At the same time, the dispersions prepared with conventional emulsifiers and polymerizable emulsifiers were compared under the same conditions. The structure and properties of the synthetic dispersion were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA). The results showed that the optimum preparation conditions of the dispersion are as follows: The amount of emulsifier was 3%, the amount of initiator was 0.5%, main monomer ratio was 1:1, the amount of functional monomer BZMA and VTES was 3%, respectively. The dispersion obtained by using DNS-86 had better thermal stability, chemical stability and the dispersion was uniformly blue, which represented small particle size. After modification, the film showed higher hydrophobicity.
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Scientific Reports
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2020
·Vol. 10
·期 1
·1-10
·
IF 3.998
Chen Junjun,Li Hailong,Zhang Lihui,Du Chao,Fang Tao,Hu Jian
With the rapid development of wearable and portable electronic devices, it is increasingly important to develop conductive paper-like films (CPFs) with the characteristics of light, thin and self-supporting. In this paper, nanofibrillated cellulose (NFC) was used as reinforcing phase of film-forming to combine with graphene oxide (GO). Then graphene-based CPFs were prepared by directly reducing the GO/NFC composite film without any additional adhesives, which effectively avoided the difficulties of dispersion and combination with other materials caused by direct using of high content graphene. Meanwhile, three representative reduction methods for direct reduction of GO/NFC composite films were also compared. The results show that 450 °C thermal reduction and hydroiodic acid reduction were more effective than ascorbic acid reduction. On this basis, hydroiodic acid reduction and thermal reduction were used to discuss the effect of NFC addition to the conductivity of the film. This occured when increasing the content of NFC from 10% to 50%, the electrical conductivity of the composite film by hydroiodic acid reduction decreased from 153.8 S/m to 22.2 S/m. While the conductivity of composite film increased first and then decreased after thermal reduction both at 450 °C and 550 °C. What’s more, when NFC content was about 16.6% the electrical conductivity reached a high level which was 86.21 S/m and 168.9 S/m, respectively. This study provides a groundwork for the further development of graphene-based CPFs with low square resistance and high conductivity in large-scale preparation.
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Protein & Cell
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2020
·Vol. 11
·期 4
·267-285
·
IF 10.164
Xu Gang,Ding Zhaozhao,Lu Qiang,Zhang Xiaoyi,Zhou Xiaozhong,Xiao Liying,Lu Guozhong,Kaplan David L
Gradient biomaterials are considered as preferable matrices for tissue engineering due to better simulation of native tissues. The introduction of gradient cues usually needs special equipment and complex process but is only effective to limited biomaterials. Incorporation of multiple gradients in the hydrogels remains challenges. Here, beta-sheet rich silk nanofibers (BSNF) were used as building blocks to introduce multiple gradients into different hydrogel systems through the joint action of crosslinking and electric field. The blocks migrated to the anode along the electric field and gradually stagnated due to the solution-hydrogel transition of the systems, finally achieving gradient distribution of the blocks in the formed hydrogels. The gradient distribution of the blocks could be tuned easily through changing different factors such as solution viscosity, which resulted in highly tunable gradient of mechanical cues. The blocks were also aligned under the electric field, endowing orientation gradient simultaneously. Different cargos could be loaded on the blocks and form gradient cues through the same crosslinking-electric field strategy. The building blocks could be introduced to various hydrogels such as Gelatin and NIPAM, indicating the universality. Complex niches with multiple gradient cues could be achieved through the strategy. Silk-based hydrogels with suitable mechanical gradients were fabricated to control the osteogenesis and chondrogenesis. Chondrogenic-osteogenic gradient transition was obtained, which stimulated the ectopic osteochondral tissue regeneration in vivo. The versatility and highly controllability of the strategy as well as multifunction of the building blocks reveal the applicability in complex tissue engineering and various interfacial tissues.
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Scientific Reports
·
2020
·Vol. 10
·期 1
·1-9
·
IF 3.998
Chen Jinxiang,Yang Jing,Ma Lanlan,Li Jun,Shahzad Nasir,Kim Chan Kyung
The antioxidant activities of 18 typical phenolic acids were investigated using 2, 2′-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. Five thermodynamic parameters involving hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton-loss electron transfer (SPLET) mechanisms were calculated using density functional theory with the B3LYP/UB3LYP functional and 6–311++G (d, p) basis set and compared in the phenolic acids. Based on the same substituents on the benzene ring, -CH 2 COOH and -CH = CHCOOH can enhance the antioxidant activities of phenolic acids, compared with -COOH. Methoxyl (-OCH 3 ) and phenolic hydroxyl (-OH) groups can also promote the antioxidant activities of phenolic acids. These results relate to the O-H bond dissociation enthalpy of the phenolic hydroxyl group in phenolic acids and the values of proton affinity and electron transfer enthalpy (ETE) involved in the electron donation ability of functional groups. In addition, we speculated that HAT, SET-PT, and SPLET mechanisms may occur in the DPPH reaction system. Whereas SPLET was the main reaction mechanism in the FRAP system, because, except for 4-hydroxyphenyl acid, the ETE values of the phenolic acids in water were consistent with the experimental results.
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Pharmacological Reports
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2020
·Vol. 72
·期 2
·400-417
·
IF 2.754
Li Yingxue,Jiang Bo,Wang Ruiyin,Wang Jingyun,Li Yachen,Bao Yongming
Background Tanshinone IIA (Tan IIA) and andrographolide (Andro) are natural compounds that are reported to exhibit anticancer activities against various types of cancers. The aim of this study is to evaluate the synergistic anticancer effects of the combination of Tan IIA and Andro, and to investigate the mechanisms of pharmacological effect and their potential applications as an anticancer therapy in clinics.
Methods The anticancer effects of the combination of Tan IIA and Andro on MCF7, SMMC7721, and BGC823 cells were explored. The apoptosis of the cancer cells was determined by MTT and AV-PI dual stain assays. The intracellular GSH level was measured by DTNB assay, and the intracellular levels of reactive oxygen species (ROS) were examined by flow cytometry. The expression of the proteins in the apoptosis pathway was determined by immunobloting. Results The combination of Tan IIA and Andro exhibited significant synergistic anticancer effects against cancer cells, especially at low concentrations. Andro reacted with the thiol group of intracellular GSH, thus disrupting the GSH redox cycle and eventually increasing the level of intracellular ROS. Tan IIA triggered p53 responses and apoptosis by binding to the DNA of cancer cells. The crosstalk between ROS and p53 exhibited a synergistic effect on the apoptosis of cancer cells. Conclusion The combination of Tan IIA and Andro showed significant synergistic effects on cancer cell apoptosis by promoting crosstalk between ROS and p53, providing a novel and effective combination that has the potential to be applied in clinical anticancer therapy. Graphic abstract
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2020
·Vol. 104
·期 11
·4927-4943
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IF 3.53
Deng Pengjun,Meng Chunyu,Wu Yan,Xu Jie,Tang Xiaoqing,Zhang Xuecheng,Xiao Yazhong,Wang Xiaotang,Fang Zemin,Fang Wei
A novel β -glucosidase, BglD1 with high β -galactosidase and transglycosidation activities, was screened and cloned from the deep-sea bacterium Bacillus sp. D1. BglD1 exhibited the maximal β -glucosidase and β -galactosidase activities at 55–60 °C and pH 5.5–6.0. The enzyme maintained approximately 50% of its original activity at 35 °C and pH 6.0 after 120-h incubation. When applied to synthesize galacto-oligosaccharides (GOS), BglD1 generated 118.3 g/L GOS (33.8% (w/w)) from 350 g/L lactose, with trisaccharide Gal- β (1 → 3)-Lac and disaccharide Gal- β (1 → 4)-Gal as the main components. Furthermore, BglD1 could hydrolyze lactose in milk and produce GOS simultaneously. Using milk as the substrate, BglD1 hydrolyzed 88.5% lactose and produced 3.3 g/L GOS after incubation at 30 °C for 1 h. To improve the transglycosidation activity, a mutant BglD1:E224T was generated based on the semi-rational design. The GOS yield of BglD1:E224T was 11.5% higher than that of BglD1 when using lactose solution as the substrate. Thus, BglD1 and the mutant could be used as beneficial alternatives of the existing β -galactosidases for the production of GOS.
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BMC MICROBIOLOGY
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2020
·Vol. 20
·期 1
·1-12
·
IF 2.989
Wang Juanjuan,Li Ruochen,Zhang Hui,Wei Gehong,Li Zhefei
Background Excessive application of chemical fertilizer has exerted a great threat to soil quality and the environment. The inoculation of plants with plant-growth-promoting rhizobacteria (PGPR) has emerged as a great prospect for ecosystem recovery. The aim of this work to isolate PGPRs and highlights the effect of bacterial inoculants on available N/P/K content in soil and on the growth of wheat under conditions of reduced fertilizer application. Results Thirty-nine PGPRs were isolated and tested for their growth-promoting potential. Thirteen isolates had nitrogen fixation ability, of which N9 ( Azotobacter chroococcum ) had the highest acetylene reduction activity of 156.26 nmol/gh. Eleven isolates had efficient phosphate solubilizing ability, of which P5 ( Klebsiella variicola ) released the most available phosphorus in liquid medium (231.68 mg/L). Fifteen isolates had efficient potassium solubilizing ability, of which K13 ( Rhizobium larrymoorei ) released the most available potassium in liquid medium (224.66 mg/L). In culture medium supplemented with tryptophan, P9 ( Klebsiella pneumoniae ) produced the greatest amount of IAA. Inoculation with the bacterial combination K14 + 176 + P9 + N8 + P5 increased the alkali-hydrolysed nitrogen, available phosphorus and available potassium in the soil by 49.46, 99.51 and 19.38%, respectively, and enhanced the N, P, and K content of wheat by 97.7, 96.4 and 42.1%, respectively. Moreover, reducing fertilizer application by 25% did not decrease the available nitrogen, phosphorus, and potassium in the soil and N/P/K content, plant height, and dry weight of wheat. Conclusions The bacterial combination K14 + 176 + P9 + N8 + P5 is superior candidates for biofertilizers that may reduce chemical fertilizer application without influencing the normal growth of wheat.
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CELLULOSE
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2020
·Vol. 27
·期 7
·4007-4018
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IF 4.21
Zhang Tao,Zhao Yan,Silverstein Michael S.
Abstract Cellulose is one of the most abundant resources in nature. Cellulose-based porous monoliths have been fabricated by direct drying of oil-in-water high internal phase emulsions (HIPEs) stabilized using either cellulose derivatives or surface-modified cellulose. The resulting cellulose-based porous polymers, however, were usually fragile, reflecting the lack of crosslinking. Herein, we report a new strategy to fabricate cellulose-based porous materials (polyurethane polyHIPEs, PU polyHIPEs) templated within non-aqueous HIPEs through the covalent crosslinking between isocyanates and unmodified cellulose. The PU polyHIPEs exhibited interconnected macroporous structures and exhibited tunable wettability from hydrophilicity/oleophilicity to hydrophobicity/oleophilicity. The PU polyHIPEs were able to absorb a wide variety of oils, exhibiting relatively large capacities and high absorption rates. We further showed that the PU polyHIPEs were robust, and they did not fail under compressive stress even at strains of 70%. The robustness, large absorption capacities, rapid absorption, and hydrophobicity/oleophilicity make these cellulose-based PU polyHIPEs suitable for oil absorption and/or oil–water separation applications. Graphic abstract
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JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 28
·13980-13994
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IF 3.553
Li Wenjun,Yang Yue,Ma Chaoyun,Song Yiju,Hong Chenglin,Qiao Xiuwen
A novel sandwich-type electrochemical immunosensor based on cuprous oxide (Cu 2 O)@copper-metal organic framework (Cu-MOF)@gold nanoparticles (Au NPs) core–shell structure was proposed. Cu 2 O@Cu-MOF@Au attached with horseradish peroxidase (HRP) triple-catalyzed hydrogen peroxide (H 2 O 2 ) for detecting CEA antigen. In this work, 50 nm Cu 2 O nanospheres were prepared. Using Cu 2 O nanospheres as the core, Cu-MOF was coated on the surface of Cu 2 O nanospheres by reaction of Cu 2 O and ligands. Subsequently, chloroauric acid was reduced to Au NPs without adding any reducing agent and Au NPs dispersed on the surface of Cu-MOF. Finally, the Cu 2 O@Cu-MOF@Au-HRP-Ab 2 nanoprobe was successfully prepared. Immunosensors had good performance due to the following reasons. Firstly, Cu 2 O, Cu-MOF and HRP have excellent catalytic properties for hydrogen peroxide. In addition, the synergistic effect of Cu 2 O, Cu-MOF and HRP promoted the reduction of hydrogen peroxide and tripled amplification of electrical signals. Here, the successfully prepared immunosensor detected carcinoembryonic antigen (CEA) sensitively, the detection range was 50 fg/mL–80 ng/mL, and the detection limit was 17 fg/mL. Besides, the proposed immunosensor had good stability, selectivity and specificity. Detection in human serum samples had good results without matrix effect. This provided a new idea for the clinical detection of tumor markers: "metal oxide—metal organic framework—precious metal nanoparticles" (MMP). Graphic abstract
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JOURNAL OF NANOPARTICLE RESEARCH
·
2020
·Vol. 22
·期 6
·1-14
·
IF 2.132
Xiong Jinyan,Li Wei,Zhao Kai,Li Weijie,Cheng Gang
A simple and environment-friendly approach to prepare zinc oxide nanoaggregates was achieved by employing ethylene glycol–H 2 O as the reaction medium. The composition and structure of the as-fabricated ZnO products were confirmed using X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption measurements. By tailoring the volume ratio of ethylene glycol to water, coral-like, flower-like, and nanoparticulate ZnO nanoaggregates were successfully synthesized. The impact of the structure of the as-obtained ZnO nanoaggregates on the photocatalytic degradation of ciprofloxacin was further studied. Under simulated solar light irradiation, the photocatalytic removal rate of coral-like, flower-like, and nanoparticulate ZnO nanoaggregates for ciprofloxacin was 45%, 80%, and 90%, respectively. The reactive species trapping experiment result indicated that the generated holes, OH − , and ·O 2 − active species mainly contributed to the degradation of ciprofloxacin. On the basis of photoluminescence spectra and photo/electrochemical measurement results, the prevention of electron-hole recombination and the rapid charge transfer upon the ZnO nanoparticle aggregates resulted in their efficient photocatalytic activity.
Engineered zinc oxide nanoaggregates for photocatalytic removal of ciprofloxacin with structure dependence
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Journal of Advanced Ceramics
·
2020
·Vol. 9
·期 3
·320-328
·
IF 2.889
Yu Zhaoju,Yang Yujing,Mao Kangwei,Feng Yao,Wen Qingbo,Riedel Ralf
A novel single-source-precursor for SiC-TaC-C nanocomposites was successfully synthesized by the chemical reaction between a polycarbosilane (allylhydridopolycarbosilane, AHPCS) and tantalum(V) chloride (TaCl 5 ), which was confirmed by Fourier transform infrared spectra (FTIR) measurement. After pyrolysis of the resultant single-source-precursors at 900 °C, amorphous ceramic powders were obtained. The 900 °C ceramics were annealed at different temperatures in the range of 1200–1600 °C to gain SiC-TaC-C nanocomposites. The phase evolution of ceramic nanocomposites was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate that the TaC starts to crystallize at lower temperature than the β-SiC. It is particularly worth pointing out that the unique core-shell structured TaC@C nanoparticles were in-situ formed and homogeneously distributed in the ceramic matrix after annealing at 1400 °C. Even at a high temperature of 1600 °C, the grain sizes of β-SiC and TaC are smaller than 30 nm, fulfilling the definition of nanocomposites. The present study related to SiC-TaC-C nanocomposites paves a new road for enriching ultra-high temperature ceramic family suitable for structural/functional applications in harsh environment.
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