SENSORS AND ACTUATORS B-CHEMICAL
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2018
·
IF 5.667
Xiang Ran,Zhen Liu,Zhenzhen Wang,Fang Pu,Jinsong Ren,Xiaogang Qu
High sensitive detection and monitoring of miRNAs in living cells have obtained considerable attention for clinical diagnosis of diseases. However, there are still enormous challenges for developing new method of quantification of miRNA in vivo. Herein, an intelligent MnO 2 -carried catalytic DNA machine (MCDM) was constructed for direct visualization of MicroRNAs in vivo with high selectivity and extremely low detection limit. MnO 2 nanosheets were used as a degradable carrier to introduce the DNA machine into cells. Benefiting from the enhanced permeability and retention (EPR) effect, the MnO 2 -carried probes could accumulate in tumor tissue, realizing a direct visualization of low concentration of miR-21 in the tumor of living animals in situ.
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RSC Advances
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2018
·Vol. 8
·期 69
·39284-39290
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IF 2.936
Youlin Jiang,Dewei Ni,Qi Ding,Bowen Chen,Xiaowu Chen,Yanmei Kan,Shaoming Dong
Nano-crystalized HfC was successfully synthesized based on an aqueous solution-derived precursor using hafnium tetrachloride and sucrose as raw materials. The precursor can be converted to pure phase HfC after pyrolysis at ∼600 °C and subsequent carbothermal reduction reaction at ∼1600 °C, with a ceramic yield of around 46.3%. Reaction mechanisms of the synthesis process are revealed based on FT-IR, TG-DSC, TEM analysis and thermodynamic calculations, etc. The obtained HfC nanoparticles possess an equiaxial shape with an average particle size of ∼73 nm. Oxygen content of the as-synthesized HfC powders is as low as 0.64 wt%, which exists in the form of an amorphous Hf–O–C thin layer covering the surface of the HfC particles. This feasible and promising method for HfC particle synthesis is believed to be suitable for the fabrication of continuous fibers reinforced HfC ceramic matrix composites.
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PubMed
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2018
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IF 1.454
Xiaoyi Yang,Binbin Zhang,Ping Li,Chaohua Guo,Jianbo Li,Xingang Wang
The present work aimed at research the physic-chemical properties of the interaction of N-decyl-O-chitosan sulfate (an amphiphilic chitosan derivative, C10-OCHS) with cetyltrimetylammonium bromide (CTAB) by the steady-state fluorescent, static/dynamic surface tension, turbidity and transmission electron microscopy (TEM). The results showed that the complex of C10-OCHS/CTAB had high surface activity and lower critical aggregation concentration. Besides, the C10-OCHS/CTAB could self-assemble into various aggregates like irregular spherical aggregates, vesicles or polydisperse aggregates from lower to higher concentrations of CTAB with a mixed C10-OCHS concentration of 200 mg/L.
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PROGRESS IN REACTION KINETICS AND MECHANISM
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2018
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IF 0.649
Mengzhi Yang,Meiling Wang
This study investigated the adsorption process of p-nitrophenol (p-NP) onto partially reduced graphene oxide (prGO) using both experiment and theoretical calculations. The maximum adsorption capacity of prGO at pH 6.0 and 293 K for p-NP was 29.94 mg g−1 which was significantly higher than previously reported using a metal-doped reduced graphene oxide composite. Systematic, comparative theoretical calculations were used to investigate the adsorption mechanism of p-NP onto graphene oxide, prGO and graphene nanosheet (GN). Calculations revealed three types of adsorption site and indicated that the adsorption force and sites were significantly affected by the quantity and type of oxygen-containing functional groups on the GN. The adsorption affinity was mainly derived from hydrogen bonds and π-π stacking which was further demonstrated by FTIR analysis. Due to its excellent adsorption performance, good recyclability and easy separation, prGO can be a promising adsorbent for the efficient elimination of p-NP from wastewater in the future.
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Journal of Materials Chemistry C
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2018
·Vol. 6
·期 20
·5506-5513
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IF 5.976
Meng Li,Xiao Zhang,Katarzyna Matras-Postolek,Hsueh-Shih Chen,Ping Yang
Fast and efficient ion-exchange reactions endow CsPbX3 nanocrystals (NCs) with superior photoluminescence (PL) properties. In this study, SnX2 (X = I, Cl) was used as a Sn precursor to conduct the cation exchange reaction, which was promoted by anion exchange between the parent CsPbBr3 NCs and the guest X in SnX2. The anion-driven cation exchange reaction occurred efficiently (10 min). CsSnI3 NCs were created by ion-exchange reactions between CsPbBr3 NCs and the SnI2 precursor. The CsSnI3 NCs retained the initial morphology of CsPbBr3 NCs and revealed a high PL efficiency (59%) and prolonged PL lifetime. In contrast, the exchange reaction of Sn2+ ions in CsPbBr3 NCs did not occur in a short time using SnBr2 as a precursor. After the cation exchange reaction, the 4f peaks of Pb ions in X-ray photoelectron spectroscopy spectra shifted to low binding energies as compared to those of the parent CsPbX3 NCs. This is ascribed to the increase in the number of Pb–oleate (Pb–OA) species. Contrary to the hot-injection method used to synthesize CsSnI3 NCs, the kinetically controlled ion exchange reactions lead to the synthesis of CsSnI3 NCs with a high structural stability. Thus, an anion-exchange-promoted cation exchange reaction is a particularly efficient versatile tool to dope Sn2+ into CsPbX3 NCs.
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CHEMISTRY OF MATERIALS
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2018
·
IF 9.89
Lei Cheng,Yao Jiang,Shi-Chao Qi,Wei Liu,Shu-Feng Shan,Peng Tan,Xiao-Qin Liu,Lin-Bing Sun
Photoresponsive adsorbents for CO2 capture attract significant attention, because the variation of adsorption capacity can be tailored conveniently by light irradiation. However, all photoresponsive adsorbents reported until now capture CO2 via physical interaction (weak sites). Thus, the selectivity of CO2 over other gases like CH4 is low, and the variation of CO2 adsorption capacity originates from pure structural change via isomerization of photoresponsive units. Despite great challenges, photoresponsive adsorbents for CO2 capture based on chemical interaction (strong sites) are extremely desirable. Here, we report for the first time the construction of photoresponsive adsorbents with chemical adsorption sites for CO2. The control of adsorption capacity is based on the interplay between active amine sites {A, [3-(methylamine)propyl]trimethoxysilane} and photoresponsive azobenzene molecules [P, 4-(3-triethoxysilylpropyl-ureido)azobenzene]. Density functional theory (DFT) calculations reveal that the negative surface potential of amines correlate with the adsorption capacity on CO2. Upon visible light (450 nm) irradiation, trans-isomers of azobenzene are formed and interact with amines, which leads to decreased surface electrostatic potential of amines, and CO2 can thus be adsorbed freely on exposed active sites. In contrast, ultraviolet light (365 nm) irradiation results in the isomerization of azobenzene from trans to cis conformation. The surface electrostatic potential of amines increases obviously, and the active sites are thus blocked. A maximum variation amount is obtained on the adsorbent with comparable density of A and P (0.34 group nm–2), which confirms the interplay between amine sites and photoresponsive molecules. Because amines are specific active sites for CO2, high selectivity of CO2 over CH4 is obtained, and such selectivity is tunable upon irradiation with UV–vis light. We thus demonstrate the successful control of CO2 captured by chemical sites through the interplay between amines and azobenzene molecules, which is impossible or difficult to realize via conventional structural change caused by isomerization of photoresponsive units.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2018
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IF 3.909
Ying Wang,Feng Bai,Qiang Luo,Mingliang Wu,Gang Song,Hongmei Zhang,Jian Cao,Yanqing Wang
Lycium barbarum polysaccharide-doxorubicin (LBP-DOX) nanoparticles were synthesized via a one-step Schiff base reaction between oxidized Lycium barbarum polysaccharide (oxidized LBP) and doxorubicin (DOX). The structure of LBP-DOX nanoparticles was characterized by multi-spectral methods, 1 H nuclear magnetic resonance ( 1 H NMR), transmission electron microscopy (TEM), and thermo gravimetric analysis (TGA). The rheological properties of LBP-DOX nanoparticles were studied. With the increase of shear rate, the viscosity of LBP and LBP-DOX nanoparticles gradually decreases at 25 °C. Under the same strain, the storage modulus (G′) and loss modulus (G″) of LBP-DOX nanoparticles were inferior to LBP. The DOX release from LBP-DOX nanoparticles was pH-dependent and was accelerated by decreasing pH. Cytotoxicity study showed that the LBP-DOX nanoparticles have significantly enhanced cytotoxicity in vitro, especially for human Hepatic cancer cell line HepG2.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2018
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IF 3.235
Wenna Zhang,Wenwen Zhang,Shuai Chen,Bin Guo,Hua Gu,Yu Xue,Zexu Xue,Jingkun Xu
In recent years, polyselenophene and its derivatives have been paid more attention due to their unique properties such as lower band gaps and redox potentials . However, the poor solubility and molecular rigidity of polyselenophene and its derivatives limit them to use in flexible optoelectronic devices. Therefore, in order to enrich the structures and properties, fully understand the structure-property relationship and further improve the electrochromic performances of polyselenophene and its derivatives, we synthesized its propyl-analogues as precursors, to electrosynthesize three conducting polymers , poly(3,4‑propylenedioxyselenophene) (PProDOS) and its alkyl-modified derivatives, poly(3,3′‑dimethyl‑3,4‑dihydro‑2H‑selenopheno[3,4‑b][1,4]dioxepine) (PProDOS-C 1 ) and poly(3,3′‑dibutyl‑3,4‑dihydro‑2H‑selenopheno[3,4‑b][1,4]dioxepine) (PProDOS-C 4 ). The electrochemical and spectroelectrochemical behaviors of PProDOS and PProDOS-C n (n = 1, 4) were investigated in detail in an ionic liquid , 1‑butyl‑3‑methylimidazolium hexafluorophosphate (BmimPF 6 ). Results showed that PProDOS-C 1 and PProDOS-C 4 exhibited superior electrochromic performances such as high optical contrast (62%) and excellent coloration efficiency (573 cm 2 C −1 ). In addition, as the alkyl chains increased, the onset oxidation potentials of monomers and the optical band gaps of polymer films decreased and the electrochemical activity of polymers increase. These polymers supply varied electrochromic colors and have prospect in display application.
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高影响因子
ACS Sustainable Chemistry & Engineering
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2018
·
IF 6.14
ZengHui Dai,ZeWen Yang,ZhiWei Chen,ZhongXiang Zhao,YongJian Lou,YanYan Zhang,TianXing Liu,FeiYa Fu,YaQin Fu,XiangDong Liu
In this study, a fully biobased composite reinforced by cotton fabrics was successfully fabricated by copolymerizing a bioderived unsaturated polyester (PEOI) with a green diluent, dimethyl itaconate (DI). The PEOI prepolymer was synthesized from itaconic acid (IA), oxalic acid (OA), and ethylene glycol (EG) via a simple polycondensation process and was characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and viscosity measurements. Subsequently, the prepolymer was dissolved in DI to prepare a polymerizable unsaturated polyester resin (UPE) with low viscosity, excellent reactivity for free radical polymerization, and good compatibility with cotton fibers. After being reinforced by cotton fabrics, the resulting composites showed satisfactory material performance, including a strong tensile strength at break of approximately 34 MPa, a glass transition temperature (Tg) of approximately 108 °C, and thermal decomposition temperatures (Td5%) ranging from 224 to 276 °C. These green composites derived from renewable resources are hopeful candidates for replacing petroleum-based UPE resins, and the family of IA derivatives may play promising roles in fabricating fully biobased composites.
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JOURNAL OF MEMBRANE SCIENCE
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2019
·
IF 7.015
Daishuang Zhang,Qian Wang,Sangshan Peng,Xiaoming Yan,Xuemei Wu,Gaohong He
An interface-strengthened cross-linked graphene oxide/Nafion212 (CLGO/Nafion212) composite membrane was successfully fabricated and served as ion conducting membrane for vanadium flow batteries (VFBs). Firstly, the surface of Nafion212 was endowed with plenty of amino groups via in situ sol-gel chemistry approach of 3-aminopropyltriethoxysilane. Subsequently, a thin layer of m -xylylenediamino-crosslinked GO was formed using the spin-coating method. The composite membrane demonstrated much lower vanadium ion permeability (0.30 × 10 −6 cm 2 min −1 ) than pristine Nafion212 (1.88 × 10 −6 cm 2 min −1 ), mainly due to the presence of a cross-linked GO layer with angstrom-scale channels. The cell assembled with CLGO/Nafion212 exhibited enhanced coulombic efficiencies ( CE s, 93.0–97.2% vs. 68.0–91.6%) and energy efficiencies ( EE s, 88.9–85.2% vs. 65.7–82.2%) compared with the one with Nafion212 at 20–100 mA cm −2 . At a constant current density of 80 mA cm −2 , the long-term cycling tests showed that the discharge capacity fading of the flow cell equipped with CLGO/Nafion212 reached 0.25% per cycle, which was much smaller than that of Nafion212 (0.47% per cycle). The above findings proved that the cell equipped with CLGO/Nafion212 displayed superior electrochemical performances than that with Nafion212, therefore CLGO/Nafion212 composite membrane showed a great potential in VFBs.
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JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 54
·期 15
·10684-10694
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IF 3.442
Shen Juanli,Zhou Yiming,Li Shengshi,Gu Pengkun,Xue Guoxin
Fe 3 O 4 magnetic nanoparticles with carboxymethyl cellulose-g-poly(acrylic acid-co-acrylic amide) hydrogel coating (Fe 3 O 4 @hydrogel) were prepared by a coprecipitation method followed by an in situ graft copolymerization. Results of various characterization techniques indicated that hydrogel materials were successfully coated on the Fe 3 O 4 surface with a weight percent of 17.5% and the Fe 3 O 4 @hydrogel has an average size of 10 nm and could be easily collected with the aid of an external magnet. Fe 3 O 4 @hydrogel was used as heterogeneous catalyst to degrade phenol in a Fenton-like reaction. Factors such as initial solution pH, H 2 O 2 concentration and catalyst dosage on the degradation efficiency of phenol were evaluated. Experimental results revealed that about 98.2% phenol and 80.4% chemical oxygen demand (COD) could be removed in 180 min under optimal conditions. Besides, Fe 3 O 4 @hydrogel presented effective phenol degradation at relatively wide pH values ranging from 3.0 to 5.0, and about 50% COD could be eliminated at pH 5.0. The improved catalytic performance of the synthesized catalyst might be ascribed to the pH-sensitive swelling, excellent dispersion, hydrophilicity and permeability of the polymer hydrogel coating. Besides, Fe 3 O 4 @hydrogel showed favorable catalytic stability and reusability with more than 55% of COD removal efficiency after three cycles.
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Nanomaterials
·
2018
·Vol. 8
·期 12
·963
·
IF 3.504
Wei Liu,Xiaolian Zhu,Chengcheng Xu,Zhao Dai,Zhaohui Meng
A new AuNPs-based thermosensitive nanoreactor (SiO2@PMBA@Au@PNIPAM) was designed and prepared by stabilizing AuNPs in the layer of poly(N,N’-methylenebisacrylamide) (PMBA) and subsequent wrapping with the temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) layer. The new nanoreactor exhibited high dispersibility and stability in aqueous solution and effectively prevented the aggregation of AuNPs caused by the phase transformation of PNIPAM. The XPS and ATR-FTIR results indicated that AuNPs could be well stabilized by PMBA due to the electron transfer between the N atoms of amide groups in the PMBA and Au atoms of AuNPs. The catalytic activity and thermoresponsive property of the new nanoreactor were invested by the reduction of the environmental pollutant, 4-nitrophenol (4-NP), with NaBH4as a reductant. It exhibited a higher catalytic activity at 20 °C and 30 °C (below LCST of PNIPAM), but an inhibited catalytic activity at 40 °C (above LCST of PNIPAM). The PNIPAM layer played a switching role in controlling the catalytic rate by altering the reaction temperature. In addition, this nanoreactor showed an easily recyclable property due to the existence of a silica core and also preserved a rather high catalytic efficiency after 16 times of recycling.Keywords:nanoreactor;distillation precipitation polymerization;catalytic reduction;thermosensitive;AuNPs
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