Food Analytical Methods
·
2018
·Vol. 12
·期 2
·431-439
·
IF 2.245
Wang Ping,Chen Yisheng,Xu Xueming,Hellmann Bernhard,Huang Caihong,Bai Yuxiang,Jin Zhengyu
This paper proposes a facile and specific method tailored for quantifying and confirming folic acid in food, based on the combination of high-performance thin layer chromatography with fluorescence densitometry and surface-enhanced Raman spectroscopy. Chromatography was carried out on silica gel plates, using methanol/ethyl acetate/ammonia (6:4:1, v / v / v ) as the mobile phase. For the first time, ozone gas was utilized as the derivative agent, which efficiently induced the appearance of strong fluorescence of the analyte. Thereafter, fluorescent densitometry measurements were carried out for quantitative purpose, offering good linearity ( R 2 > 0.999) and sensitivity (0.7–1.4 mg/kg). In addition, the applicability and reliability of the established method was validated with food and food supplement samples, showing good agreement with the data obtained by conventional HPLC-UV as the benchmark, but with remarkably higher efficiency. Apart from that, the in situ-obtained surface-enhanced Raman spectroscopic fingerprint of bands under optimized conditions (532-nm incident laser and tenfold concentrated silver nanoparticles) enabled unambiguous identification of the targeted compound, serving as a convenient and affordable tool to prevent potential mistake from false-positive results.
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CELLULOSE
·
2018
·Vol. 25
·期 12
·7017-7029
·
IF 3.809
Guan Qingshun,Song Ruyuan,Wu Weibing,Zhang Lei,Jing Yi,Dai Hongqi,Fang Guigan
Abstract With water-soluble CdTe quantum Dots (QDs) as fluorescent labels and TEMPO-oxidized cellulose nanofibrils (CNF) as matrix, dual-color QD-encoded microspheres were prepared by mechanical spraying, freeze-molding and subsequent electrostatic cross-linking by calcium ion. The entire preparation process was accomplished in aqueous phase without any chemical treatment. The nanocellulose microspheres possessed porous structure and were able to be dispersed stably in water in the form of hydrogels. CdTe QDs were efficiently fixed in the network of intertwined nanofibrils via hydrogen bonding with CNF, making the microspheres to obtain high photoluminescence (PL) intensity and identifiable encoding signals consisting of seven kinds of microsphere arrays. The crystalline structure and chemical composition of both CdTe QDs and CNF were not affected during the preparation process. The comparision of PL behaviors of CdTe QDs and QD-encoded microspheres in different media indicate that CNF matrix provided good protection of QDs and improved the PL intensity and photostability. Graphical Abstract Dual-color CdTe-encoded nanocellulose microspheres were prepared via pure physical process in aqueous phase. The fluorescent microspheres possessed high photoluminescence intensity and identifiable seven kinds of encoding signals. The nanocellulose matrix provided good protection of CdTe QDs and improved the photoluminescence intensity and photostability.
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ANNALS OF BIOMEDICAL ENGINEERING
·
2018
·Vol. 46
·期 9
·1254-1266
·
IF 3.405
Huang Ruiying,Gao Xiangkai,Wang Jian,Chen Haoxiang,Tong Chunyi,Tan Yongjun,Tan Zhikai
Small-diameter tissue-engineered vascular grafts are urgently needed for clinic arterial substitute. To simulate the structures and functions of natural blood vessels, we designed a novel triple-layer poly(ε-caprolactone) (PCL) fibrous vascular graft by combining E-jet 3D printing and electrospinning techniques. The resultant vascular graft consisted of an interior layer comprising 3D-printed highly aligned strong fibers, a middle layer made by electrospun densely fibers, and an exterior structure composed of mixed fibers fabricated by co-electrospraying. The biocompatible triple-layer graft was used for in vivo implantation, and results demonstrated that the longitudinally-aligned fibers within the lumen of the graft could enhance the proliferation and migration of endothelial cells, while maintained good mechanical properties. The exterior layer provided a pathway that encouraged cells to migrate into the scaffold after implantation. This experimental graft overcame the limitations of conventionally electrospun vascular grafts of inadequate porosity and lowly cell penetration. The unique structure of the triple-layer vascular graft promoted cell growth and infiltration in vivo , thus provided an encouraging substitute for in situ tissue engineering.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 28
·28628-28641
·
IF 2.8
Wang Wenbing,Wu Yanqing
Biological clogging in porous media was an important concern in the design of bio-augmented permeable reactive barriers ( Bio - PRBs ) that were used to remediate groundwater with dense non-aqueous phase liquids (DNAPLs). Here, we used laboratory sandbox experiments to develop and calibrate reactive transport models (C1 and C2) simulating 1,1,1-trichloroethane (1,1,1-TCA) change in heterogeneous saturated porous media. The routine (1,1,1-TCA chain kinetic reactions) and subroutine (the relationship between hydraulic conductivity ( K ) and time ( t )) were included in the model computer code. The simulation results suggested that the model C1 had the applicability for simulating contaminant transport and fate in bio-augmented flow field. By using the model C1 which was suitable for constant K condition, the performance of different types of Bio - PRBs was evaluated, and the regularity of contaminants chain kinetic reactions in different heterogeneous saturated porous media was obtained. The results demonstrated that Bio - PRBs in immobilized microorganism ( IM ) protocol were more superior to Bio - PRBs in free microorganism ( FM ) protocol. In addition, by using the model C2 (updated model C1) which was suitable for decreasing K condition, the different and optimized regularity of contaminants transport and transformation was obtained. The results showed that microbial growth which further decreased K was beneficial to preventing the transport of contaminants and accelerating the transformation of contaminants. However, the negative effects of biological clogging on hydraulic conductivity and relative hydraulic conductivity ratio in FM Bio - PRBs were significantly stronger than that in IM Bio - PRBs . Deploying IM Bio - PRBs for groundwater remediation would be much more efficient and meet the design criteria. The research work had guiding significance to engineering and provided consultation for designing and optimizing Bio - PRBs system. To make the design and optimization of Bio - PRBs system convenient, it was very essential to choose the suitable mathematical model (C1 or C2).
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Scientific Reports
·
2018
·Vol. 8
·期 1
·1-6
·
IF 4.122
Wang Wucong,Gai Yanzhe,Xiao Ding,Zhao Yaping
Nanoscrolls (NSs) assembled from two-dimensional nanosheets have emerged as a novel type of one-dimensional nanomaterials because of their unique topological features and properties. The scale-up preparation of the NSs is crucial for their foundational and applied research. Herein, we report a general and straightforward approach for efficiently converting two-dimensional nanosheets into the NSs with high yield. We demonstrated the converting process by illustrating the formation of the graphene nanoscrolls through characterizing their morphology and structure using a scanning electron microscope, transmission electron microscope, Raman spectra, and X-ray diffraction spectra. The graphene sheets with a few-lay number were converted immediately and entirely into the graphene nanoscrolls when they mixed with an ethanol solution of silver nitrate at room temperature. The as-prepared graphene nanoscrolls were confirmed to be formed via the layer-by-layer assembly of graphene triggered by silver cyanide formed in site. Also, we extended this approach to construct the nanoscrolls of the hexagonal boron nitride, molybdenum disulfide, and tungsten disulfide, respectively, from their corresponding two-dimensional nanomaterials. In a broader context, this approach paves a significant new way for the large production of the NSs with cost-efficiency.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 11
·6621-6636
·
IF 1.674
Kang Chunli,Xiao Kunkun,Yao Zhifu,Wang Yuhan,Huang Dongmei,Zhu Ling,Liu Fang,Tian Tao
Pure phase ZnTiO 3 was prepared through a sol–gel process, then graphene-ZnTiO 3 nanocomposites were synthesized by a hydrothermal method using the prepared ZnTiO 3 nanoparticles and graphene oxide as precursors. X-ray diffraction results revealed the production of pure cubic ZnTiO 3 at 600 °C. ZnTiO 3 was anchored on the graphene nanosheets, demonstrating a spherical morphology in transmission electron microscope images. The existence of chemical bond Ti–O–C in the nanocomposites was proved by Fourier-transforming infrared spectroscopy. UV–Vis diffusive reflection spectra indicated that the absorption edge of the nanocomposites shifted towards the visible region. The photocatalytic activity of the composites was tested through the photocatalytic degradation of methyl blue under simulated solar irradiation. The results showed that the photocatalytic activity of the nanocomposites was obviously increased in contrast to pure ZnTiO 3 , which was strongly affected by the crystalline structure of ZnTiO 3 and the concentration of graphene. The enhanced photocatalytic activity was mainly attributed to the conglomeration inhibition of ZnTiO 3 nanoparticles, the electron transfer between ZnTiO 3 and graphene and the extended absorption range. Furthermore, other contaminants such as tetracycline, Rhodamine B and methyl orange were tested under the same conditions to investigate the photocatalytic performance of the photocatalysts. The reusability tests indicated that the prepared composites exhibited good stability.
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Scientific Reports
·
2018
·Vol. 8
·期 1
·1-9
·
IF 4.122
Xu Peiman,Li Jingwei,Luo Jiaxian,Wei Licheng,Zhang Dawei,Zhou Dan,Xu Weiming,Yuan Dingsheng
Earth-abundant and efficient bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are highly significant for renewable energy systems. However, the performance of existing electrocatalysts is usually restricted by the low electroic conductivity and the limited amount of exposed active sites. In this work, (Fe 0.2 Ni 0.8 ) 0.96 S tubular spheres supported on Ni foam have been prepared by a sulfuration of FeNi layered double hydroxide spheres grown on Ni foam. Benefiting from the unique tubular sphere architecture, the rich inner defects and the enhanced electron interactions between Fe, Ni and S, this electrocatalyst shows low overpotential of 48 mV for HER at 10 mA cm −2 in 1.0 mol L −1 KOH solution, which is one of the lowest value of non-previous electrocatalyts for HER in alkaline electrolyte. Furthermore, assembled this versatile electrode as an alkaline electrolyzer for overall water splitting, a current density of 10 mA cm −2 is achieved at a low cell voltage of 1.56 V, and reach up to 30 mA cm −2 only at an operating cell voltage of 1.65 V.
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 12
·1-8
·
IF 5.705
Sui Chengji,Liu Fei,Tang Lihua,Li Xue,Zhou Yunlei,Yin Huanshun,Ai Shiyun
A sensitive and selective photoelectrochemical (PEC) method is described for the detection of protein kinase A (PKA) activity based on the use of graphite-like carbon nitride (g-C 3 N 4 ) and the CdS quantum dots (QDs). Firstly, a complex was synthesized from g-C 3 N 4 and gold nanoparticles (AuNPs). It was employed as both the PEC-active material and as a support for immobilization of peptides. The latter were assembled on an ITO electrode modified with g-C 3 N 4 -AuNPs and subsequently phosphorylated by PKA in the presence of adenosine 5′-[γ-thio]triphosphate (ATP-S). Finally, CdS quantum dots (QDs) were introduced on the ITO in order to increase the PEC response of g-C 3 N 4 based on the Cd-S binding between the QDs and thiol groups. Under the optimal conditions and a typical working voltage of −0.3 V, the method has a dynamic range that extends from 0.05 to 50 unit·mL −1 , with a 0.017 unit·mL −1 lower detection limit. The method was successfully applied to the quantification of the inhibitory effect of ellagic acid on the activity of PKA, and to monitor enzyme activity in cell lysates.
Schematic of a sensitive and selective photoelectrochemical biosensor for the detection of protein kinase A activity. It is based on the use of graphite-like carbon nitride and CdS quantum dots.
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CELLULOSE
·
2018
·Vol. 26
·期 3
·2035-2046
·
IF 3.809
Zhao Yongsheng,Dang Wanbin,Si Lianmeng,Lu Zhaoqing
Abstract The application of Aramid/mica composite paper in high-voltage electric insulation is hampered by its limited breakdown strength and mechanical robustness. In this work, Aramid fiber/Mica-NFC composite papers with varied amount of nanofibrillated cellulose (NFC) were fabricated by vacuum-assisted self-assembly process, wherein NFC was used as carrier/adhesion polymer. The Aramid fiber/Mica-NFC composite papers exhibited high mechanical strength (~ 29.04 MPa), superior dielectric properties (~ 14.87 kV/mm) and good thermal stability (~ 300 °C). Importantly, NFC acts as interfacial layer since the physical properties of NaOH-Urea treated Aramid/Mica-NFC composite significantly decreased. Based on visualization of NFC by fluorescence tracking, the addition of NFC favors the formation of biomimetic multilayer structure. Furthermore, the co-continuous double-network-like multilayer structured composite achieved an integrated strong and tough character. Therefore, our work shed light on the importance of constructing rational-designed microstructures for the preparation of high-performance composite papers. Graphical abstract
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 6
·5149-5159
·
IF 2.993
Chen Kexu,Kang Ming,Lu Ai,Chen Lin,Song Lixian,Sun Rong
The internal dispersion structure of silica fillers in polymer matrix is significant for design and fabricating high-performance polymer composite. In order to explore the relationship between fillers spatial dispersion states and mechanical properties, we use superficial fluorescent labeling to achieve fillers visualization in polymer matrix with laser scanning confocal microscopy. Through the effect of fluorescent silane coupling agent, the uniform red fluorescence characteristics were shown on the silica surface. The 2D-planar and 3D-spatial dispersion states of silica fillers in rubber matrix can be accurately observed with fluorescence imaging technology. The results by Avizo software statistics show that high-content silica fillers in composite tend to undergo dissociation of aggregates. These dissociated small volume aggregates which facilitate the interaction between particles and rubber matrix to dissipate mechanical energy effectively and rapidly improve rubber toughness. This successful visualization method opens a new avenue in spatial dispersion description of fillers aggregates in organic–inorganic composite.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 5
·4024-4037
·
IF 2.993
Shen Guozhu,Ren Junzhao,Zhao Bin,Mei Buqing,Wu Hongyan,Fang Xumin,Xu Yewen
Lightweight hollow mesoporous carbon spheres (HMCSs) with large air/carbon interface in the mesoporous shell and interior void have been successfully synthesized via a ‘polymerization–pyrolysis–etching’ route. The complex permittivity of the HMCSs can be easily adjusted by carbonization temperature in the frequency range of 2–18 GHz, which is in favor of designing absorbers in different frequency range. The minimum reflection loss value of − 26.4 dB at 6.7 GHz with a thickness of 5.0 mm and the maximum effective absorption bandwidth (less than − 10 dB) of 5.5 GHz can be gained for the HC-700/paraffin composite with only 10 wt% HMCSs and a thickness of 2.5 mm. To enhance the magnetic loss and improve the impedance matching of the HMCSs, electroless plating methods are employed to deposit Ni and Fe nanoparticles on the HMCSs. Benefiting from the dielectric loss, magnetic loss and impedance characteristic, the new lightweight Fe/HMCSs composite with 40 wt% HC–Fe shows superior microwave absorption properties. The stronger reflection loss can be obtained at all designed thicknesses, and the peak value of reflection loss is less than − 20 dB at each thickness of greater than 1.2 mm. The minimum reflection loss reaches − 49.7 dB at 13.0 GHz, and the effective absorption bandwidth is 4.0 GHz with a thickness of 1.6 mm. This research is providing a new insight in the preparation and design of lightweight microwave absorption materials.
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 10
·1-7
·
IF 5.705
Kong Caiyun,Gao Linna,Chen Zhengbo
An aptamer based assay is described for the colorimetric detection of adenosine. The presence of adenosine triggers the deformation of hairpin DNA oligonucleotide (HP1) containing adenosine aptamer and then hybridizes another unlabeled hairpin DNA oligonucleotide (HP2). This leads to the formation of a double strand with a blunt 3′ terminal. After exonuclease III (Exo III)-assisted degradation, the guanine-rich strand (GRS) is released from HP2. Hence, the adenosine-HP1 complex is released to the solution where it can hybridize another HP2 and initiate many cycles of the digestion reaction with the assistance of Exo III. This leads to the generation of a large number of GRS strands after multiple cycles. The GRS stabilize the red AuNPs against aggregation in the presence of potassium ions. If, however, GRS forms a G-quadruplex, it loses its ability to protect gold nanoparticles (AuNPs) from salt-induced AuNP aggregation. Therefore, the color of the solution changes from red to blue which can be visually observed. This colorimetric assay has a 0.13 nM detection limit and a wide linear range that extends from 5 nM to 1 μM.
Schematic presentation of a colorimetric aptamer biosensor for adenosine detection based on DNA cycling amplification and salt-induced aggregation of gold nanoparticles.
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