Silicon
·
2020
·Vol. 14
·期 2
·385-392
·
IF 1.499
Wen Qin,Jiang Chunxia,Liu Wanqiang,Zeng Zhi,Gao Jinwei,Zheng Yuhui
Quantum dots generate unique luminescent and chemical properties due to the ultra-small particle sizes. In this contribution, a novel silicon nanoparticles (Si-NPs)-based platform has been established via (3-aminopropyl) trimethoxysilane (APS) and ascorbic acid (AA) as raw materials within only 30 min. A switched off effect has been achieved for the determination of Ni 2+ ions and the strategy has been simply realized by recording the luminescence changes in the green band of Si-NPs. This developed approach possesses a variety of merits such as label free, low cost, easy post-treatment and convenient operations. The linear equation range is yielded between 0 and 20 μM with the detection limit of 1.73 μM. The nano-sensor provides a versatile route for the monitoring of mercury ions in practical environments.
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3 Biotech
·
2020
·Vol. 10
·期 12
·1-9
·
IF 1.798
Zhang Jun,Tian Miao,Lv Pengmei,Luo Wen,Wang Zhiyuan,Xu Jingliang,Wang Zhongming
Long-chain fatty acids are widely used in food and chemical industries, and the enzymatic preparation of fatty acids is considered an environmentally friendly process. In the present study, long-chain fatty acids were prepared by the enzymatic hydrolysis of rapeseed oil with a genetically engineered lipase. Because thermophilic lipase has strong stability at higher temperatures, it was more suitable for the industrial production of long-chain fatty acids. Therefore, the thermophilic lipase BTL2 from Geobacillus thermocatenulatus was efficiently expressed in E. coli BL21(DE3) cells with an enzyme activity of 39.50 U/mg followed by gene codon optimisation. Experimental results showed that the recombinant lipase BTL2 exhibited excellent resistance to certain organic solvents ( n -hexane, benzene, ethanol, and butanol). The metal cation Ca 2+ and the non-ionic surfactant Triton-100X enhanced enzyme activity by 7.36% and 56.21% respectively. Moreover, the acid value of the liberated long-chain fatty acids by hydrolysing rapeseed oil was approximately 161.64 mg KOH/g at 50 °C in 24 h, the hydrolytic conversion rate was 91.45%, and the productivity was approximately 6.735 mg KOH/g h. These results suggested that the recombinant lipase BTL2 has excellent hydrolytic performance for rapeseed oil and showed great potential for the enzymatic preparation of long-chain fatty acids.
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高影响因子
Journal of Advanced Ceramics
·
2020
·Vol. 10
·期 1
·88-97
·
IF 2.889
Wang Zixin,Lin Hui,Zhang Dawei,Shen Yiming,Li Yang,Hong Ruijin,Tao Chunxian,Han Zhaoxia,Chen Lei,Zhou Shengming
In this study, deep-red emitting Mg 2 TiO 4 :Mn 4+ phosphor ceramics were synthesized by the high temperature solid-state reaction method. The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum (FWMH) value of 31 nm. The peak wavelength was located at 658 nm, which matched the demanded wavelength for photosynthesis. The crystal field strength ( D q ) and the Racah parameters ( B and C ) were estimated by the Tanabe-Sugano diagram. The thermal conductivity of the Mg 2 Ti( 0.999 )O 4 :0.001Mn 4+ ceramic was 7.535 W/(m·K) at room temperature, which was one order of magnitude higher than that of the traditional packaging method using the silicone gel. A set of phosphor converted LEDs were fabricated by mounting the phosphor ceramics onto the 460 nm blue LED chips and the CIE coordinates can move from the blue region to the purple light region with the thickness of the ceramic increasing. These results indicated that the Mg 2 TiO 4 :Mn 4+ phosphor ceramic was suitable for plant lighting when combined with a blue LED chip.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 11
·1-8
·
IF 6.232
Zou Jin,Zhong Wei,Gao Feng,Tu Xiaolong,Chen Shangxing,Huang Xigen,Wang Xiaoqiang,Lu Limin,Yu Yongfang
A multilayer Bi-BTC/reduced graphene oxide (Bi-BTC/rGO) (BTC, 1,3,5-benzenetricarboxylic acid) film electrode was adopted to construct a highly sensitive Pb 2+ electrochemical sensor. The multilayer Bi-BTC/rGO films were prepared via alternate cast of Bi-BTC and graphene oxide (GO) on a glassy carbon electrode, followed by electro-reduction of the GO components. Bi-BTC has porous broom-like structure and its organic ligand has abundant functional groups, which are favorable for Pb 2+ adsorption and preconcentration. The introduction of rGO layer improves the conductivity of the MOFs material. Moreover, the multilayer composite structure greatly increased the exposure of active sites and the surface area of reactive contact, finally realizing the highly sensitive detection of Pb 2+ . Pb 2+ was determined by differential pulse anodic stripping voltammetry and the response current was recorded at − 0.62 V. The [Bi-BTC/rGO] 2 electrode provides a wide linear response ranging from 0.062 to 20.72 μg/L and a low limit of detection (LOD) of 0.021 μg/L (S/N = 3) for Pb 2+ , which is lower than the guideline value proposed by the World Health Organization. The method has been applied to determine Pb 2+ in industrial wastewater with recoveries of 99.2–104% and RSDs of 3.4–4.0% ( n = 3).
Graphical abstract Graphical abstract Schematic representation of an electrochemical sensor for the detection of Pb 2+ was designed based on long broom-like structure bismuth(II) metallic organic framework/reduced graphene oxide ([Bi-BTC /rGO] 2 )
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 5
·6269-6282
·
IF 2.478
Chen Zhangxu,Fu Minglian,Zheng Bingyun,Zhu Danchen,Chen Zefan
The influencing factors of chelator, reaction times, and Yb 3+ /Tm 3+ -doped concentration on the formation of NaYF 4 :Yb,Tm crystals with various morphologies have been investigated and determined. It is found that NaYF 4 :Yb,Tm with various morphologies and different phases can be tuned. Compared with the addition of ethylene diamine tetra acetic acid, hexagonal nanoprism-like β-NaYF 4 :Yb,Tm with a mean length of ~ 1300 nm and diameter of ~ 100 nm is prepared in the presence of oleic acid, which preferentially orients along with the [0001] direction more quickly than others. Systematical research on the emission of Yb 3+ /Tm 3+ -doped NaYF 4 crystals with microrod, hexagonal microprism, and nanoplate has implied that these obtained crystals with unique optical properties are closely related to their morphologies, phases, and sizes. In addition, a possible growth mechanism of co-existence of α- and β-NaYF 4 phases is proposed. It can be expected to illustrate the formation mechanism for the upconversion crystals or other rare-earth upconversion materials and to import these highly luminescent microcrystals or nanocrystals to environmental remediation by full solar energy spectra.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2021
·Vol. 327
·期 2
·811-819
·
IF 1.371
Du Ziyao,Li Bolin,Jiang Chao,Sun Ruopei,Chen Suwen
A metal–organic framework, UiO-66-NH 2 , was designed, synthesized and characterized in this study. By conducting solvothermal method, Salicylaldehyde (Sal) and 2,4-dihydroxybenzaldehyde (MHBA) were grafted onto UiO-66-NH 2 via post-treatment to obtain the functionalized material UiO-66-Sal and UiO-66-MHBA. The three materials above were characterized, and the effects of solid–liquid ratio, pH, ionic strength, and oscillation time on U(VI) adsorption were studied. The relevant experimental results fitted well with pseudo-second-order kinetic equation and thermodynamic adsorption model.
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Stem Cell Research & Therapy
·
2020
·Vol. 11
·期 1
·1-11
·
IF 5.116
Yang Zhi,Song Zhicheng,Nie Xin,Guo Kaijin,Gu Yan
Background Biological composite scaffolds are increasingly being used in abdominal wall reconstruction but still have certain shortcomings. The present study describes here a novel three-dimensional (3D) scaffold fabricated by combining 3D printing (3DP) and electrospinning (ESP). Methods Biological composite scaffolds are composed of integrated 3DP interconnected macrofiber and random ESP microfiber networks. The 3DP scaffold retains intact 3D architecture and mechanical properties, while the ESP network serves as a cell entrapment system at the extracellular matrix (ECM) scale. Biological composite scaffolds are implanted in a defective rat abdominal wall to detect if it could induce early vascularization and reconstruction of the tissue defect. Results SEM analysis reveals a pore diameter of 424.47 ± 58.49 μm and a porosity of 70.46 ± 2.48% for biological composite scaffolds. In the in vitro test of cell proliferation, biological composite scaffolds do not affect rat dermal fibroblast proliferation in a time- and dose-dependent manner. The animal experiments show tissue remodeling and early angiogenesis as compared to 3DP scaffolds. Conclusions Our experiment prepares a biological scaffold with both a macro- and microscale structure by ESP and 3DP technology. Thus, the integration of 3DP and ESP techniques provides a new set of smart scaffolds for abdominal wall defect and hernia repair.
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高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2021
·Vol. 127
·期 2
·1-9
·
IF 2.584
Ma Rongrong,Pathak Rajesh,Zheng Dongping,Zhang Yingjie,Xing Jie,Liu Junhong,Jiang Yuanyuan,Xiao Mingxing,Wu Fan
In this paper, a ZnO array is first prepared on the conductive glass by hydrothermal method, and then a seed layer of CuO nanoparticles is deposited on the surface of ZnO nanorods to form a core–shell ZnO/CuO nanoarray. Following, the dendritic CuO nanorods are grown on ZnO nanorods by hydrothermal method, constructing a three-dimensional ZnO/CuO nano-heterogeneous hierarchical structure array and applied in photoelectrochemical cell. Our three-dimensional ZnO/CuO nano-heterogeneous hierarchical structure shows obvious absorption of visible light from 500 to 900 nm. The current–time curves reveal that the photocurrent is greatly enhanced after dendritic CuO grows on the ZnO nanorod array. Furthermore, the charge dynamics processes in the core–shell ZnO/CuO nano-heterostructure array and the three-dimensional ZnO/CuO nano-heterostructure array are studied by comparing electrochemical impedance spectroscopy and intensity modulation photocurrent (photovoltage) spectroscopy. Although the photo-generated charge transfer rate in the ZnO/CuO core–shell structure is slightly faster than the three-dimensional ZnO/CuO hierarchical structure, the recombination life of the photo-generated charge is increased by nearly two orders of magnitude in the three-dimensional ZnO/CuO nano-heterostructure array. The three-dimensional ZnO/CuO nano-heterostructure array has a good potential application in the field of photoelectric conversion devices and photocatalysis.
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JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2021
·Vol. 29
·期 7
·2227-2235
·
IF 3.667
Cui Mingfei,Li Yanhui,Sun Yong,Wang Huimin,Li Meixiu,Li Liubo,Xu Wenshuo
Due to public concern about tetracycline (TC), it is imperative to eliminate this compound from the environment. This article describes the preparation of an efficient and low-cost porous copper alginate/graphene oxide (CA/GO) composite material by freeze-drying. The application of tetracycline removal in the presence of persulfate (PS) was studied. The effects of pH, PS, catalyst dosage and tetracycline concentration on adsorption and degradation were investigated. The synthesized composites were characterized by Scanning electron microscope (SEM), Fourier Transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). The degradation rate of tetracycline increases with the increase of the compound dose, and decreases with the increase of the initial pH. The adsorption of tetracycline by this catalyst is suitable for Langmuir model. Under the optimum conditions, the removal efficiency of tetracycline was up to 98%. The high reactivity of the composite material is closely related to its redox ability. At the same time, the reusability of the material was studied. After being recycled four times under the same conditions, the removal rate of tetracycline reached about 85%.
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International Journal of Minerals Metallurgy and Materials
·
2020
·Vol. 27
·期 12
·1711-1722
·
IF 1.713
Wang Jun-xiang,Tu Ji-guo,Jiao Han-dong,Zhu Hong-min
Aluminum storage systems with graphite cathode have been greatly promoting the development of state-of-the-art rechargeable aluminum batteries over the last five years; this is due to the ultra-stable cycling, high capacity, and good safety of the systems. This study discussed the change of electrochemical behaviors caused by the structural difference between flake graphite and expandable graphite, the effects of temperature on the electrochemical performance of graphite in low-cost AlCl 3 –NaCl inorganic molten salt, and the reaction mechanisms of aluminum complex ions in both graphite materials by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge measurements. It was found that flake graphite stacked with noticeably small and thin graphene nanosheets exhibited high capacity and fairly good rate capability. The battery could achieve a high capacity of ∼219 mA hg −1 over 1200 cycles at a high current density of 5 Ag −1 , with Coulombic efficiency of 94.1%. Moreover, the reaction mechanisms are clarified: For the flake graphite with small and thin graphene nanosheets and high mesopore structures, the reaction mechanism consisted of not only the intercalation of \({\rm{AlCl}}_4^ - \) anions between graphene layers but also the adsorption of \({\rm{AlCl}}_4^ - \) anions within mesopores; however, for the well-stacked and highly parallel layered large-size expandable graphite, the reaction mechanism mainly involved the intercalation of \({\rm{AlCl}}_4^ - \) anions.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 28
·期 23
·30101-30110
·
IF 4.223
Bian Xiaoxue,Gao Yongfei
An unexplored attributing molecular mechanism of Cd toxicity is interference with the epigenetic machinery, such as DNA methylation, processes that are crucial for early fetal development. In order to investigate the effects of Cd on the expression of metallothionein (MT) and Dnmts transcripts, markers of DNA methylation, and signaling pathway gene expression, zebrafish embryos were exposed during 24 hours post-fertilization (starting at maximum 8-cell stage) to 0.0089, 0.089, and 0.89 μM Cd. The results showed that the Cd accumulation in zebrafish embryo reached a stable level after 12 hpf, and the Cd accumulation at individual time points was significantly different among different concentration groups. MT mRNA fold was significantly positive with the Cd content in embryos. We observed that the expression level of DNA methyltransferase ( Dnmts ) in the 0.089 μM Cd exposure group was significantly up-regulated. Dnmt1 expression was significantly up-regulated in the 0.89 μM Cd exposure group, and Dnmt3s expression and global methylation levels were significantly down-regulated. Cd up-regulated ErbB-3 gene expression, down-regulated ErbB-4 gene expression, and neutralized ErbB-1 gene expression. Cd activated Ca 2+ , MAPK-JUK , p38 MAP kinase, PI3K-AKT , and VEGF signaling pathway genes, indicating these pathway genes related to Cd exposure level. The results are helpful to clarify the molecular mechanism of DNA methylation in zebrafish embryo under metal pressure and further interference with the epigenetic machinery.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2021
·Vol. 56
·期 12
·7321-7333
·
IF 4.22
Wang Ni,Zhang Hao,Liu Songyu,Peng Bo,Deng Ziwei
Various pollutants in wastewater including water-insoluble oils and water-soluble toxic organic pollutants, have been threatening ecosystems and human health, making wastewater purification difficult. Inspired by the hierarchical structures and chemical compositions of lotus leaf, we combined the usage of polydopamine (PDA) chemistry and photocatalytically active TiO 2 to develop a facile approach toward composite PDA-based TiO 2 coated mesh with restorable superhydrophobicity. In this procedure, PDA assisted loading of TiO 2 nanoparticles onto stainless steel mesh with a result of micro/nanoscale hierarchical surface was achieved via a single-step solvothermal method. After modified with 1 H , 1 H , 2 H , 2 H -perfluorodecyltriethoxysilane, this mesh became superhydrophobic. The TiO 2 coated mesh exhibited enhanced superhydrophobicity, excellent environmental stability, robust chemical resistance and high mechanical durability. Moreover, it has been demonstrated the high separation capacity and extraordinary recyclability for various oils collection from water due to its special surface superhydrophobicity. Importantly, such a mesh possessed photocatalytic activity due to the embedded TiO 2 , which allowed for the effective degradation of organic pollutants under UV irradiation, representing a plausible way to restore superhydrophobic surface by photocatalytically decomposing the attached contaminants. This investigation suggests a green and facile way to prepare superhydrophobic materials with restored surface wetting property, which will be useful for wastewater purification. Graphical abstract
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危险品化学品经营许可证（带存储）