Food Biophysics
·
2019
·Vol. 15
·期 2
·188-195
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IF 2.411
Fang Sheng,Peng Xinling,Liang Xianrui,Shen Jian,Wang Jian,Chen Jie,Meng Yuecheng
In this study, the antifungal compound natamycin was encapsulated in methyl- β -cyclodextrin (heptakis(2,6-di-O-methyl)- β -cyclodextrin, Me- β -CD) to improve its aqueous solubility and stability. The aqueous solubilities of natamycin in the presence of β -CD, 2-hydroxypropyl- β -CD, 6-O- α -maltosyl- β -CD, and Me- β -CD were compared. The Me- β -CD showed the best result to increase the solubility of natamycin in aqueous. The pH stability of natamycin was improved by the formation of inclusion complex with Me- β -CD, especially at acidic conditions. The degradation of natamycin under UV-light exposure followed first-order kinetics with half-life times ( t 1/2 ) of 59.2 and 157.5 min in pure form and Me- β -CD inclusion complex, respectively. The in vitro antifungal activities of natamycin/Me -β -CD complex against Aspergillus niger food pathogen were evaluated. The results demonstrated that the natamycin/Me -β -CD complex could effectively improve the aqueous solubility and photostability of natamycin without compromising in antifungal activities. Finally, the molecular inclusion mechanisms and geometrical configurations of the natamycin/Me -β -CD complex were studied using molecular dynamics simulations. This research may lead to the development of more effective inclusion-based delivery systems to encapsulate and protect lipophilic antimicrobial agents for food applications.
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MICROCHIMICA ACTA
·
2019
·Vol. 187
·期 1
·1-7
·
IF 5.479
Xu Tingting,Dai Hongqi,Jin Yongcan
An electrochemical sensor for Pb(II) is described that exploits (a) the outstanding adsorption ability of chitosan modified with quaternary ammonium groups (CQAS; cationic) and of lignosulfonate (LSN; anionic), and (b) the good electrical conductivity of polypyrrole nanoparticles (PPy NPs). A glassy carbon electrode (GCE) was modified with PPy NPs and polydopamine, and CQAS and LSN are used as dispersants in PPy. The modified GCE exhibits high selectivity and sensitivity for Pb(II) in the 0.1 to 50 μM concentration range, with a 55 nM detection limit (3σ method). The redox potentials for Pb(II) is around −0.55 V, and the sensor is not interfered by the presence of Hg(II) and Cu(II). The time dependent stability test showed that this sensor can maintain good reproducibility for one month. This sensor was applied to the determination of Pb(II) in wastewater samples.
An electrochemical sensor for lead(II) is described that exploits the outstanding adsorption ability of chitosan that carries quaternary ammonium groups (CQAS), of lignosulfonate (LSN), and the good electrical conductivity of polypyrrole nanoparticles. CQAS and LSN are used as dispersants in PPy. The sensor exhibits high selectivity and sensitivity for Pb(II) in the range of 0.1 to 50 μM with a 55 nM detection limit.
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高影响因子
IONICS
·
2019
·Vol. 26
·期 4
·1711-1719
·
IF 2.289
Chen Fei,Wang Bo,Wang Fei,Jiang Yunpeng,Dong Bengang,Zhao Haimi,Wang Dianlong
In this paper, a precast solid electrolyte interface (SEI) film strategy was explored for Li metal anode with longer cycling life. At the current density of 0.5 mA cm −2 for 0.5 mAh cm −2 of Li, electrochemical performance tests showed that the half cell with optimized precast SEI film had a coulombic efficiency of more than 99.0% after 620 cycles. Cyclic voltammetry, electrochemical impedance spectrum, mechanical properties, ionic conductivity, scanning electron microscopy, infrared spectroscopy, thermogravimetry, etc., were used to analyze the performance of SEI film. The results showed that when 0.04 mol of lithium bis(oxalato)borate was added into 7.0 g of the poly(vinylidene fluoride- co -hexafluoropropylene) matrix as the components of SEI film, the half cell with the precast SEI film showed the best cycling performance. When different kinds of lithium salts were added into the matrix, the morphology and property after curing were different, which affected the tensile strength, elongation, ionic conductivity, electrolyte absorption rate, and thermal decomposition temperature. Moreover, it had also been found that the strength and ionic conductivity were the main factors in determining the performance of the precast SEI film.
A precast solid electrolyte interface (SEI) film strategy was explored for Li metal anode with longer cycling life.
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CELLULOSE
·
2019
·Vol. 27
·期 3
·1745-1761
·
IF 3.917
Wan Caiyan,Liu Mingsheng,Tian Peixiu,Zhang Guangxian,Zhang Fengxiu
Abstract A bio-based P–N synergistic flame retardant ammonium salt of d -Panthenol-tri (methylphosphonic acid) (ADPTMPA) was synthesized using a formaldehyde-free and solvent-free strategy for the highly efficient preparation of durable flame-retardant cotton. The ADPTMPA structure was verified by 1 H NMR, 13 C NMR and 31 P NMR. FT-IR test revealed successful grafting of the flame retardant onto the cotton through P–O–C covalent bonding. The morphologies and structures of pure cotton and treated cotton were characterized by SEM and XRD, and the elemental compositions of cotton samples were analyzed by EDX. Volatile pyrolysis products of treated cotton were analyzed by TG-IR. Flame retardancy and washability of treated cotton were analyzed by limiting oxygen index (LOI) and vertical flammability tests (VFT). The LOIs of 40 wt% ADPTMPA treated cotton before and after 50 laundering cycles was determined as 46.5% and 35.8%, respectively. VFT showed the treated cotton exhibited no smoldering and continuous burning. All carbon lengths of treated cottons were less than 60 mm. The heat release rate and total heat release of treated cotton were decreased by 91.34% and 58.01% compared with pure cotton, respectively. There was 29.42 wt% carbon residual remaining when the treated cotton was exposed to heat flow of 35 kw/m 2 . The treated cotton exhibited excellent flame retardancy and washability. Additionally, the mechanical properties and whiteness of the treated cotton were well-maintained. Graphic abstract
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2019
·Vol. 141
·期 2
·783-796
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IF 2.471
Ding Jiong,Yu Liming,Wang Xiaona,Xu Qiyue,Yang Suijun,Ye Shuliang,Jiang Juncheng
The accelerating rate calorimetry is a powerful tool for thermal hazard evaluation. However, the existing kinetics approaches ignore the fact that the thermal inertia is varying during the pseudo-adiabatic reaction because of the changing of the sample’s heat capacity and heat loss. To overcome this shortcoming, the expression of the thermal inertia is amended based on the heat balance and transfer in this article. The arithmetic product of the sample’s heat capacity and the amended thermal inertia is obtained by merging the kinetic results of the DSC and ARC data. Then, the data from the ARC are corrected and the more reasonable values of the kinetic parameters are computed based on the varying thermal inertia consideration. With the typical n -order and autocatalytic decomposition experiments under the different sample masses, the validity of the proposed kinetic approach is verified. Meanwhile, the hypotheses of the proposed approach are analyzed and discussed in the end of the article.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 27
·期 2
·1888-1897
·
IF 2.914
Wang Ying,Wang Luxing,Deng Xiaoyan,Gao Hongtao
Waste biomass can be recycled to prepare biochar for soil restoration, in which process soil fertility would not be lost. In this work, biochar was prepared from waste pomelo peel, combined with ZnO, to be used to immobilize Cu(II) in contaminated soil, whose maximum adsorption capacity was up to 216.37 mg g −1 . Due to combination of ZnO, the BET surface area of biochar increased from 2.39 to 18.53 m 2 g −1 . Meanwhile, the surface functional groups increased, which was conducive to fixation of metal ion on the surface of biochar. Both pseudo-second-order kinetics and Langmuir isotherm model fit the experimental data well. Adsorption was easy to happen since the adsorption site on the surface of biochar/ZnO had a strong affinity with Cu(II). In addition, mechanism investigation indicated that Cu(II) was bond with biochar/ZnO mainly by non-bioavailable state (75.6%) primarily. It inferred that biochar/ZnO was an efficient and promising passivator in reducing heavy metal risk in soil.
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高影响因子
CELLULOSE
·
2019
·Vol. 27
·期 3
·1341-1355
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IF 3.917
Zhang Xueqin,Luo Wenhan,Xiao Naiyu,Chen Mingjie,Liu Chuanfu
Abstract The aim of this study is to prepare functional hemicellulose (HC) films with flexibility, thermoplasticity and UV-shielding ability. HC was firstly esterified with vinyl benzoate and then reinforced with poly(vinyl alcohol) (PVA) and nano-zinc oxide (ZnO). After esterification, the solubility of benzoated HC (BH) increased, while the thermal stability decreased. Moreover, esterification could transform HC into crystalline nature and endow HC with tunable transition temperature ( T g ). Adding equivalent mass of PVA and 1% ZnO increased the thermal stability of BH/PVA/ZnO films. XRD and DSC analyses showed the new crystalline structure and the decreased T g of films, probably due to the interactions among BH, PVA and ZnO. From SEM, the cross sections of films were dense, rough, and were connected to form the network structure, promoting the uniform insertion of ZnO into the matrix. The films showed moderate tensile strength and good flexibility with the maximum elongation at break of 87.18%. In addition, the water vapor permeability (WVP) and oxygen permeability (OP) values of BH/PVA/ZnO film were 2.08 × 10 −10 g/m s Pa and 0.95 cm 3 μm/m 2 d kPa, respectively. Moreover, the film with 1% ZnO exhibited excellent UV-shielding properties with the percentage blocking of UV-A and UV-B of 99.34% and 99.99%, respectively. Graphic abstract
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JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 55
·期 7
·2994-3004
·
IF 3.442
Ji Jun,Wang Yinghui,Zhang Xuelai,Chen Yue,Munyalo Jotham Muthoka,Liu Sheng
Supercooling of phase change materials (PCMs) during solidification is a major problem in cold thermal energy storage (CTES), which reduces energy efficiency and aggravates energy waste. This study focuses on the supercooling characteristics of PCMs under heterogeneous nucleation, which provides a new idea for researching the influence of different dispersants on the supercooling degree of aqueous solution. The optimal ratios of CNTs water dispersant (TNWDIS) and polymer polyacrylic acid sodium (PAAS) to multi-walled carbon nanotubes (MWCNTs) in mannitol aqueous solution are determined through microstructure and cooling characteristics. How these two surfactants and MWCNTs with different concentrations and particle sizes influence the supercooling degree of nanofluids are investigated. The results indicate that the effect of PAAS is greater than that of TNWDIS. Furthermore, under the action of two dispersants and particle sizes of MWCNTs, the fitting equations of supercooling changing with the concentration of MWCNTs are obtained. In the light of the heterogeneous nucleation theory, with the enlargement of the particle size and the diminution of the contact angle affected by the dispersants, the interfacial free energy of heterogeneous nucleation of PCMs on the surface of nanoparticles is reduced. The supercooling degree therefore decreases. Specifically, the nucleation mechanism is deduced and analyzed through the contact angle and nucleation free energy formula.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 29
·7747-7760
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IF 3.286
Wang Chenxi,Feng Keyu,Fu Zhifei,Yang Wenzhi,Wang Ping,Wang Tao,Gao Xiumei,Yu Heshui,Han Lifeng
Peiyuan Tongnao capsule (PTC) is a prescription medicine of traditional Chinese medicine with the effects of “nourishing the kidney,” “replenishing essence,” “extinguishing wind,” and “opening the meridian”. PTC is also widely used in clinic for the treatment of stroke and chronic cerebral circulation insufficiency. However, the quality control studies of PTC are hitherto quite limited. Here, we aim to fully utilize an advanced chromatography–mass spectrometry hyphenation technique to qualitatively and quantitatively evaluate the quality of PTC. Firstly, a two-dimensional liquid chromatography/quadrupole-Orbitrap mass spectrometry (2D-LC/Q-Orbitrap-MS) approach was established for multicomponent characterization. An offline 2D-LC system fitted with an Xbridge Amide column and an HSS T 3 column showed an orthogonality of 0.63 and a theoretical peak capacity of 6930. Eleven fractions of PTC, after hydrophilic interaction chromatography (first dimension), were further analyzed by reversed-phase ultrahigh-performance liquid chromatography/Q-Orbitrap-MS (UHPLC/Q-Orbitrap-MS, second dimension) using a rapid negative/positive switching mode. Consequently, 178 compounds were separated, 96 of which were identified or tentatively characterized. Secondly, co-condition fingerprint analysis of seven constituted herbal medicines of PTC was performed to unveil ten active ingredients (citric acid, rehmannioside D, echinacoside, paeoniflorin, verbascoside, liquiritin, 2,3,5,4′-tetrahydroxystilbene-2- O - β - d -glucoside, cinnamic aldehyde, glycyrrhizic acid, and emodin) as the quality markers of PTC. Thirdly, a UHPLC/PRM ad (adjusted parallel reaction monitoring) method was established and validated to quantify the ten marker compounds in 14 batches of PTC. To the best of our knowledge, this is the first study to report comprehensive multicomponent characterization, authentication, and quality evaluation of PTC, which could be used to lay the foundation for quality control, biological efficacy research, and further development.
Graphical abstract
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高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 21
·19247-19253
·
IF 2.195
Feng Li,Dong Chengli,Jiang Wenlian,Gu Xiaoling,Xiao Mengjia,Li Chenxi,Ning Zhanglei,Gao Daojiang
Hierarchically uniform three-dimensional europium-based metal–organic frameworks (Eu-MOFs) have been successfully fabricated via a facile and mild liquid precipitation method at room temperature. The morphology, structure, and composition of samples are well characterized by scanning electron microscopy, X-ray powder diffraction, fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analyses, respectively. These well-arranged Eu-MOFs architectures show red emission corresponding to the 5 D 0 / 7 F 2 transition of the Eu 3+ ions under UV light excitation. Remarkably, these Eu-MOFs samples exhibit clear “turn-off” quenching response for styrene vapors with high selectivity and reusability. This Eu-MOFs fluorescent sensor realizes fast recognition for styrene with a response time of less than 1 min at room temperature. Moreover, good detection reproductivity could also be achieved in this sensor. Considering the easy preparation, high selectivity and excellent repeatability, the sensor system provides a convenient and reliable detection of volatile organic compound in everyday applications.
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MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 11
·1-9
·
IF 5.479
Liu Chao,Zhao Li,Liang Dongxia,Zhang Xiaoru,Song Weiling
A photocathode is described for the determination of microRNA-21 by using CuInS 2 as an active photocathode material. Exonuclease III assisted target recycling amplification was employed to enhance the detection sensitivity. The TATA-binding protein (TBP) was applied to enhance steric hindrance which decreases the photoelectrochemical intensity. This strategy is designed by combining the anti-interference photocathode material, enzyme assisted target recycling amplification and TBP induced signal off, showing remarkable amplification efficiency. Under the optimized conditions, the detection limit for microRNA-21 is as low as 0.47 fM, and a linear range was got from 1.0 × 10 −15 M to 1.0 × 10 −6 M.
Schematic representation of sensitive photoelectrochemical detection of microRNA-21.CuInS 2 is used as an active photocathode material. Combined Exonuclease III assisted target recycling amplification and TATA-binding protein decreased of photoelectrochemical intensity, the detection limit was 0.47 fM with good selectivity. (miR-21: microRNA-21; CS: chitosan).
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高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2019
·Vol. 55
·期 4
·1489-1498
·
IF 3.442
Shi Mengni,Lin Tingrui,Hu Yang,Peng Jing,Li Jiuqiang,Zhai Maolin
Functionalization of graphene oxide (GO) with octavinyl polyhedral oligomeric silsesquioxane (OvPOSS) is achieved by gamma-ray radiation-induced grafting under mild conditions. The grafting yield of OvPOSS-grafted GO (GOP), calculated by the content of silicon in GOP using X-ray photoelectron spectroscopy, increases gradually with the increase in the absorbed dose. The grafting of OvPOSS onto GO not only improves its thermal stability, but also increases its distance between the adjacent graphitic layers which could improve the reactivity of GO. In contrary to the hydrophobic GOP prepared via the traditional chemical method, it dramatically becomes more hydrophilic with the increase in the absorbed dose due to the introduction of nitrogen-containing group under irradiation, and the surface of GOP becomes super-hydrophilic at an absorbed dose of 50 kGy. Furthermore, GOP still has excellent electrical insulation property due to the grafting of insulated OvPOSS. Consequently, this work paves a feasible and green way for the functionalization of GO with improved performances.
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