BIOMETALS
·
2019
·Vol. 32
·期 2
·251-264
·
IF 2.455
Liu Xiao-Li,Ye Sen,Li Hua-Wei,Lu Bo,Yu Yan-Qin,Fan Yu-Peng,Yang Wei-Jun,Yang Jin-Shu
Rimicaris exoculata (Decapoda: Bresiliidae) is one of the dominant species among hydrothermal vent communities along the Mid-Atlantic Ridge. This shrimp can tolerate high concentrations of heavy metals such as iron, but the mechanisms used for detoxification and utilization of excess metals remain largely unknown. Ferritin is a major iron storage protein in most living organisms. The central heavy subunit of ferritin (H-ferritin) possesses ferroxidase activity and converts iron from Fe 2+ to Fe 3+ , the non-toxic form used for storage. In the present study, the H-ferritin RexFrtH was identified in the hydrothermal vent shrimp R. exoculata , and found to be highly expressed in the gill, the main organ involved in bioaccumulation of metals, at both RNA and protein levels. Accumulation of RexFrtH decreased from efferent to afferent vessels, coinciding with the direction of water flow through the gills. Fe 3+ was localized with RexFrtH, and in vitro iron-binding and ferroxidase assays using recombinant RexFrtH confirmed the high affinity for iron. Based on these results, we propose a model of iron metabolism in R. exoculata gills; ferrous iron from ambient hydrothermal water accumulates and is converted and stored in ferric form by RexFrtH as an iron reservoir when needed for metabolism, or excreted as an intermediate to prevent iron overload. The findings expand our understanding of the adaptation strategies used by shrimps inhabiting extreme hydrothermal vents to cope with extremely high heavy metal concentrations.
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Scientific Reports
·
2019
·Vol. 9
·期 1
·1-12
·
IF 4.011
You Ning,Zhang Chenxi,Liang Yachao,Zhang Qi,Fu Peng,Liu Minying,Zhao Qingxiang,Cui Zhe,Pang Xinchang
An unconventional but facile approach to prepare size-tunable core/shell ferroelectric/polymeric nanoparticles with uniform distribution is achieved by metal-free atom transfer radical polymerization (ATRP) driven by visible light under ambient temperature based on novel hyperbranched aromatic polyamides (HBPA) as a functional matrix. Cubic BaTiO 3 /HBPA nanocomposites can be prepared by in-situ polycondensation process with precursors (barium hydroxide (Ba(OH) 2 ) and titanium(IV) tetraisopropoxide (TTIP)) of ferroelectric BaTiO 3 nanocrystals, because precursors can be selectively loaded into the domain containing the benzimidazole rings. At 1200 °C, the aromatic polyamide coating of cubic BaTiO 3 nanoparticles are carbonized to form carbon layer in the inert environment, which prevents regular nanoparticles from gathering. In addition, cubic BaTiO 3 nanoparticles are simultaneously transformed into tetragonal BaTiO 3 nanocrystals after high temperature calcination (1200 °C). The outer carbon shell of tetragonal BaTiO 3 nanoparticles is removed via 500 °C calcination in air. Bi-functional ligand can modify the surface of tetragonal BaTiO 3 nanoparticles. PMMA polymeric chains are growing from the initiating sites of ferroelectric BaTiO 3 nanocrystal surface via the metal-free ATRP technique to obtain core/shell ferroelectric BaTiO 3 /PMMA hybrid nanoparticles. Changing the molar ratio between benzimidazole ring units and precursors can tune the size of ferroelectric BaTiO 3 nanoparticles in the process of polycondensation, and the thickness of polymeric shell can be tailored by changing the white LED irradiation time in the organocatalyzed ATRP process. The dielectric properties of core/shell BaTiO 3 /PMMA hybrid nanoparticles can be also tuned by adjusting the dimension of BaTiO 3 core and the molecular weight of PMMA shell.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 2
·1-8
·
IF 5.479
Xia Hongjun,Wang Jun,Chen Gang,Liu Jiawei,Wan Guangpin,Bai Quan
Monodisperse SiO 2 @SiO 2 core-shell silica microspheres (CSSM) with enlarged mesopores perpendicular to the particles surface were prepared using a dual-templating approach. With cetyltrimethyl ammonium bromide as the template and octyltrimethyl ammonium bromide as an auxiliary chemical, the pore size can be enlarged from 2.6 to 10.6 nm. The average shell thickness can be increased from 31 nm to 97 nm by adjusting the concentrations of the surfactants under continuous addition of tetraethyl orthosilicate. After coating twice, the resulting CSSM has a uniform mesoporous shell of about 198 nm thickness and a narrow pore size distribution. The CSSM were then modified with octadecyltrichlorosilane to give a material referred to as CS-C18. It was evaluated by separating the mixture of methylbenzene (toluene), ethylbenzene, n-propylbenzene, n-butylbenzene, n-amylbenzene and hexylbenzene. The baseline separation of the six alkyl benzenes is achieved within 2 min. Compared to a commercial column of type BEH-C18, CS-C18 shows a faster and better separation even at lower back pressure. It was also applied to the fast separation of benzo[a]pyrene, salbutamol, ractopamine and clenbuterolin residues in pork samples. The high column efficiency and better reproducibility suggest that the CSSM can be used as a matrix for fast separation and analysis of several kinds of small analytes.
A dual-templating approach was utilized to produce the core shell microsphere with controllable mesopore channels by using hexadecyltrimethylammonium bromide (CTAB) as the template and trioctylmethylammonium bromide (TOMAB) as an auxiliary chemical to enlarge the size of CTAB micelles.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 6
·1261-1271
·
IF 3.286
Sun Ya Kun,Sun Guang-Ying,Jia Man,Yang Jian,Liu Zhao-Sheng,Huang Yan-Ping,Aisa Haji Akber
One of the main challenges in large-scale applications of molecularly imprinted polymers (MIPs) is the significant amount of template needed in polymer preparation. A new strategy based on room-temperature ionic liquids (RTILs) was suggested to solve this problem by reducing the amount of template in the polymerization recipe. The MIP was synthesized with a mixture of dimethyl sulfoxide and RTIL (1-butyl-3-methylimidazolium tetrafluoroborate) as porogen, in which chlorogenic acid (CGA) was used as template, 4-vinylpyridine (4-VP) as functional monomer, and ethylene glycol dimethacrylate (EDMA) as cross-linker. The influence of polymerization variables, including CGA concentrations, and the ratio of 4-VP to EDMA on imprinting effect were investigated comprehensively. Moreover, the properties involving the column permeability, the number of binding sites, and the polymer morphology of the CGA-MIP monoliths were studied thoroughly. The MIP monolith had an excellent column permeability (1.53 × 10 −13 m 2 ) and allowed an ultra-fast on-line SPE, which dramatically shortens the separation time (< 10 min) and improves the separation efficiency. At high flow velocity (5.0 mL min −1 ), 50 μL of the extract from Eucommia ulmoides leaves can be loaded directly on the CGA-MIP monoliths and CGA with high purity can be obtained with a recovery of 89.01 ± 0.05%. As a conclusion, the resulting RTIL-induced approach of preparing MIP may be an effective tool in fabricating MIP in a low-cost way.
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CELLULOSE
·
2019
·Vol. 26
·期 9
·5211-5226
·
IF 3.917
Jiang Lang,Li Ke,Yang Huiyu,Liu Xin,Xu Weilin,Deng Bo
Flower-shaped hydromagnesite (MgO-P) and magnesium oxide (MgO) micro spheres were synthesized via precipitation-aging method with and without calcination. The disassociated nano flaky petal of around 50 nm (~ 20 nm in thickness) of MgO-P and MgO by sonication were used as flame-retardants for the electrospun cellulose acetate (CA)/MgO-P or CA/MgO nanofiber. SEM, XRD, FTIR, HRTEM were used to characterize all related products. TGA was used to analyze the detailed decomposition procedures of bare, MgO-P, and MgO doped CA nanofiber. Three evaluation methods including broken time after heating, thermography during heating, and combustion observation were adopted to compare the flame-retardancy of composited nanofibers. Doped CA nanofibers showed best flame-retardancy by extending the heat-induced broken time from 0.46 to 12.09 s, which is 26.3 times that of CA nanofiber. The flame of CA/MgO-P and CA/MgO could be self-extinguished once the ignition source was removed. No smoke and size shrinkage could be observed during the combustion of CA/MgO-P or CA/MgO nanofibers. Corresponding flame-retarding mechanism of Mg-based nano flaky petal was proposed.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 16
·16482-16492
·
IF 2.914
Tong Dongshen,Fang Kai,Yang Haiyan,Wang Jie,Zhou Chunhui,Yu Weihua
Sodium alginate (SA) is a linear biopolymer, which is the nontoxic, biodegradable, and rich in carboxyl and hydroxyl groups. In the paper, the SA-based hydrogel bead was prepared by the cationic hectorite clay and anionic sodium alginate with a simple ionic gelation method under freeze-drying, and the adsorption properties were evaluated by the removal of copper ions from aqueous solutions. The composites were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm (BET), thermal analysis (TG), and Fourier transform infrared spectroscopy (FT-IR). The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data and the Langmuir, Freundlich, Dubinin–Radushkevich (D-R), and Temkin models were applied to describe the adsorption isotherms. The results showed that the adsorption process was found to follow the Freundlich isotherm model and the maximum sorption capacity was observed to be 160.28 mg/g under the initial concentration from 10 to 700 mg/L at 45 °C. Adsorption kinetics data fitted well with pseudo-second-order rate model. The porous structure of the composite was responsible for the adsorption of Cu 2+ ions. But the adsorption ability could be improved by pH. Finally, the adsorption mechanism was suggested.
Graphical abstract
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JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2018
·Vol. 28
·期 1
·423-430
·
IF 1.34
Wang Bin,Du Jinjing,Gao Shoukun,Fang Zhao,Zhu Jun,Li Linbo
NiFe 2 O 4 /nano-TiN ceramics were fabricated by a two-step cold-pressing sintering process. Effect of sintering atmosphere (air, nitrogen, argon) on the synthesis process of NiFe 2 O 4 /nano-TiN ceramics was investigated. The DSC-TG and XRD analysis results indicated that besides principal phases of NiO and NiFe 2 O 4 , new-phase Ni 3 TiO 5 formed in the sintered ceramics under the three sintering atmospheres, and metallic phase including iron and nickel appeared in the sintered samples with inert gas (nitrogen, argon) sintering condition. Microstructure analysis results showed that considerable quantity of micropores appeared in the ceramic samples sintered under inert gases (argon, nitrogen), but lower porosity (3.0, 3.6%) and higher densities (4.78 g/cm 3 , 4.51 g/cm 3 ) can be obtained, comparing to the both values (14.4%, 4.17 g/cm 3 ) for the ceramic samples sintered under air atmosphere. Besides, the average bending strength and elastic modulus of the samples sintered under argon is 113.75 MPa and 7.13GPa, which is higher than that of 75.12 MPa, 5.42GPa and 91.96 MPa, 6.26GPa for the samples synthesized under air and nitrogen, separately. When changing sintering atmosphere from air to inert gases (argon, nitrogen), the fracture model of the 4 wt.%nano-TiN/NiFe 2 O 4 ceramics synthesized at 1400 °C for 4 h transformed from intergranular fracture to intergranular-transgranular fracture.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 6
·4601-4618
·
IF 2.993
He Si-Qing,Wang Jing,Wu Dan-Dan,Sang Xiao-Jing,Su Fang,Zhu Zai-Ming,Zhang Lan-Cui
A series of highly ordered mesoporous ethane-bridged organosilica composite materials functionalized by carboxyethyltin group, SnR–Si(Et)Si– X (SnR and Si(Et)Si denote [Sn(CH 2 ) 2 COOH] 3+ and ethane-bridged organosilica groups, respectively), were successfully designed through one-step co-condensation–hydrothermal method. The pore morphology and textural properties, Sn(IV) coordination environment, the type of acid site, Brönsted and Lewis acid strength were systematically characterized by LXRD, TEM observation, N 2 porosimetry measurements, MAS NMR ( 29 Si, 13 C, 119 Sn), UV–Vis diffuse reflectance spectrum, as well as 1 H and 31 P MAS NMR, FT-IR analysis of adsorbed pyridine, acid–base titration. Composite materials SnR–Si(Et)Si– X possess Brönsted and Lewis acid sites, which originates from –COOH in [Sn(CH 2 ) 2 COOH] 3+ group and bridging OH in [Si(OH)SnR] group as well as tetrahedral coordination framework Sn(IV) in the open configuration [SnR(SiO) 3 (OH)], respectively. The above 2D hexagonal mesoporous structure with unique textural properties, double acid sites (Brönsted and Lewis acid sites) and hydrophobic surface make SnR–Si(Et)Si– X exhibit excellent acid catalytic activity, reusability and water tolerance toward ketalization of cyclohexanone with glycol in absence of azeotrope agent at low temperature.
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BULLETIN OF MATERIALS SCIENCE
·
2018
·Vol. 41
·期 6
·1-7
·
IF 0.925
Chen Huajun,Yang Gangbin,Ding Wuxiu
In view of the compatibility between carriers of antimicrobial agents and ceramic glaze, mesoporous alumina was employed as the carrier of silver ions and silver-loaded mesoporous alumina was synthesized by hydrothermal and adsorption methods. The liquid medium microdilution method and the spread plate methods were studied to evaluate antimicrobial efficiency of silver-loaded mesoporous alumina. \(\hbox {N}_{2}\) adsorption/desorption, HRTEM images and low-angle X-ray diffraction experiment prove the existence of fine mesoporous structure of mesoporous alumina and silver-loaded mesoporous alumina. The chelation of ammonia can improve the adsorption capacity of silver nitrate on mesoporous alumina and adsorption capacity increases by 18 times in the presence of ammonia. The adsorption behaviour of silver nitrate can be described by a multilayer adsorption isotherm of BET and the adsorption principle of silver nitrate on mesoporous alumina is multilayer adsorption in the presence of ammonia. The surface area, pore volume and pore-size distribution of silver-loaded mesoporous alumina are obviously smaller than those of mesoporous alumina due to the blockage of channel by silver-ammonia complex. The antibacterial test results indicate that silver-loaded mesoporous alumina have favourable antibiotic property and MIC \(\le \) 240 \(\upmu \hbox {g}\) \(\hbox {ml}^{-1}\) against Escherichia coli , Staphylococcus aureus and Salmonella . The diameter of inhibition zone of silver-loaded mesoporous alumina is 26 mm against Escherichia coli , 24 mm against Staphylococcus aureus and 22 mm against Salmonella enterica .
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 45
·期 3
·1263-1279
·
IF 1.674
Feng Sheng,Wang Runbai,Feng Shanshan,Zhang Zhihui,Mao Lebao
A novel ternary complex photocatalyst (UiO-66/ g -C 3 N 4 /Ag) was fabricated by chemical protonation coating and photodeposition and its physicochemical parameters, crystal morphology, and electrochemical properties characterized using a series of techniques. Proper addition of g -C 3 N 4 and Ag effectively enhanced the separation and mobility of photoinduced charge and improved the visible-light absorption and thereby the catalytic performance. Degradation experiments on target contaminants such as Rhodamine B (RhB) dye and 2,4-dichlorophenoxyacetic acid (2,4- d ) showed that the photocatalytic ability of UiO-66/ g -C 3 N 4 /Ag(15) was greatly increased compared with the parent material. Moreover, the composite could be regenerated by a simple ethanol washing process and exhibited stability and high reusability over six cycles. Finally, experiments on trapping of active species revealed that superoxide radicals (·O
− 2
), holes (h + ), and hydroxyl radicals (·OH) were primarily responsible for the photodegradation of RhB and 2,4- d .
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-8
·
IF 5.479
Liu Jianbo,Shang Yonghui,Zhu Qiuyan,Zhang Xinxue,Zheng Jianbin
A voltammetric immunoassay for the carcinoembryonic antigen (CEA) was developed using silver metal-organic frameworks (Ag-MOFs) as a signal probe. The Ag-MOFs contained a substantial amount of Ag(I) whose electrochemical signal was relatively stable. Therefore, the Ag-MOFs were viable signal probes. The signal can be detected without previous acid dissolution and preconcentration steps. This simplifies the detection steps and reduces the detection time. If CEA binds to its antibody on the modified electrode, the signal for Ag(I) becomes reduced. Measurements were best performed at a potential as low as 0.07 V (vs. SCE) which made the electrode hardly sensitive to potential electroactive interferents. Under optimized conditions, the method included a wide linear response range (0.05 to 120 ng mL −1 ) and a low detection limit of 8.0 fg mL −1 (S/ N = 3). The synthesis of Ag-MOFs is relatively simple, and Ag-MOFs are not only used as nanocarriers for immobilizing anti-CEA but also acted as electroactive materials for a signal probe. The voltammetric immunoassay is stable, inexpensive, sensitive, and selective. Based on these advantages, the method holds great promise for applications in the point-of-care disease and environmental monitoring.
Schematic presentation of a novel electrochemical immunoassay for the carcinoembryonic antigen (CEA) using silver metal-organic frameworks (Ag-MOFs) as a signal probe.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 8
·1-12
·
IF 5.479
Wang You,Huo Danqun,Wu Huixiang,Li Jaiwei,Zhang Qinghai,Deng Bo,Zhou Jing,Yang Mei,Hou Changjun
Carboxylic acids (CAs) have been reported as potential biomarkers of specific diseases or human body odors. A visual sensor array is described here that is based on indicator displacement assays (IDAs). The arrays were prepared by spotting solutions of the following metal complexes: Murexide-Ni(II), murexide-Cu(II), zincon-Zn(II) and xylenol orange-Cu(II), with the capability of discrimination of 15 carboxylic acids (CAs) and the quantitation of pyruvic acid (PA). Clear differences can be observed through distinctive difference maps obtained within 5 min by subtraction of red, green and blue (RGB) values of digital images after and before exposure to analytes. After an analysis of multidimensional data by pattern recognition algorithms including HCA, PCA and LDA, excellent classification specificity, and accuracy of >96% were obtained for all samples. The IDA array exhibited a linear range from 10 to 1500 μM with a theoretical detection limit of 3.5 μM towards PA. Recoveries of real samples varied from 84.8% to 114.3%. As-fabricated IDA sensor array showed an excellent selectivity among other organic interfering substances and a good batch to batch reproducibility, demonstrating its robustness. All these observations suggested that the IDA sensor array is one of the most promising paths for the discrimination of CAs.
Schematic diagram of indicator displacement assay (a), the procedure for acquisition of difference maps (b), and pattern recognitions for CAs (c). The method uses hierarchical cluster analysis (HCA), principal component analysis (PCA) and linear discriminant analysis (LDA)
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