FOOD CHEMISTRY
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2021
·
IF 7.514
Jing Li,Kunpeng Gao,Francesco Secundo,Xiangzhao Mao
Chitin, one of the most abundant renewable biopolymers on Earth, is commercially available from crustacean wastes. One critical step in converting chitin to high-value products is its degradation by chitinolytic enzymes to N -acetyl- d -glucosamine (GlcNAc), which plays a significant role in functional food and pharmaceutical industries. Here, we cloned and biochemically characterized two novel β - N -acetylglucosaminidases named SvNag2557 (family-84) and SvNag4755 (family-3) from Streptomyces violascens ATCC 27968. Both SvNag2557 and SvNag4755 exhibited strict substrate specificity toward N -acetyl chitooligosaccharides with GlcNAc as the sole product. Thus, a one-pot production for pure GlcNAc from chitin by an enzyme cocktail reaction was further developed. Under the co-action of an endo-type chitinase SaChiA4 and SvNag2557 (mass ratio 1:2), the final conversion rates of colloidal chitin and ionic liquid pretreated chitin to GlcNAc were 80.2% and 73.8% with GlcNAc purities of 99.7% and 96.8%, respectively.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2021
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IF 4.464
Dongju Fu,ZiYue Zhu,Jianjun Chen,Liqiang Ye,XinRui Song,XieRong Zeng
It is paramount important to design and explore excellent bifunctional oxygen electrocatalysts to conquer or weaken the shortcomings encountered by Zinc-air batteries at present. Herein, a novel N -doped hollow carbon tubes modified by uniform NiCo 2 O 4 nanocrystals ( N -HCTs@NiCo 2 O 4 ), has been developed as an extremely efficient bifunctional catalyst. The hollow structure of N -HCTs possesses a large specific surface area of 610.60 cm g −1 which provides abundant active N -dopant sites for the oxygen reduction reaction, whereas the NiCo 2 O 4 nanocrystals serve as the positive phase for the oxygen evolution reaction. It is found that the efficient bifunctional activity is obtained by establishing a coupling interface between N -HCTs and NiCo 2 O 4 . The N -HCTs@NiCo 2 O 4 composite has a half-wave potential of 0.81 V toward ORR and the overpotential of 330 mV at a current density of 10 mA cm −2 toward OER as compared with noble metal catalysts. The N -HCTs@NiCo 2 O 4 as the cathode catalyst for Zinc-air batteries exhibits superior peak power density (150 mW cm −2 ), specific capacity up to 779 mAh g −1 , and good stability even after 100 h of cyclic charge/discharge cycles N -HCTs@NiCo 2 O 4 has good prospects for practical applications of non-precious metal catalysts in the cathode of Zinc-air batteries.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2019
·Vol. 136
·期 20
·47473
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IF 2.188
Xiaoning Wang,Yacheng Xing,Xihui Zhao,Quan Ji,Yanzhi Xia,Xiaomei Ma
To seek adsorptive hydrogels with high stability, poly(N,N-dimethylacrylamide) (PDMAM)-based hydrogels were fabricated employing vinylated chitosan as a macro-crosslinker. The prepared hydrogels achieves a maximum compressive stress above 11 MPa (98% strain), a maximum tensile strength, and fracture elongation of 0.037 MPa and 929%. The recovery ratios after three consecutive compressions (90% strain) and 1 h's resting (600% stretch) exceed 94% and 85%, respectively. The optimal adsorption effect (>90% removal efficiency) is achieved at pH 3 and 318 K in 2.5 h using hydrogels crosslinked by 9.77 wt % chitosan. The kinetic study indicates that the experimental data fit to the pseudo-second-order kinetic model better. The adsorption isotherm fits to the Freundlich model, indicating nonhomogeneous adsorption of the dyes on the hydrogels. Most adsorbed dyes are desorbed in 2 h at pH 10 and 318 K, both adsorption/desorption efficiencies exceed 90% after five adsorption–desorption cycles, confirming reusability of the hydrogels. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47473.
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JOURNAL OF HAZARDOUS MATERIALS
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2018
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IF 6.434
Genming Li,Wenbo Zhao,Muyuan Chai,Yanhong Li,Qingming Jia,Yuan Chen
In the present work, liquid-liquid phase-change absorption of SO 2 was investigated using N , N -dimethylcyclohexylamine (DMCHA) as an absorbent, and high boiling liquid paraffin (LP) as a solvent to reduce volatilization of the absorbent. The homogenous solution was split into two immiscible phases upon SO 2 loading. The phase-change mechanism was attributed to the polarity variation of DMCHA before and after absorption by forming the charge-transfer complex DMCHA·SO 2 . The viscosity of the lower phase reached a maximum value of 24.5 mPa s at the absorption capacity of 1 mol SO 2 /mol DMCHA, and the viscosity of the corresponding upper phase was 46.4 mPa s. Both are lower than the reported viscosity of most ionic liquids. This solution exhibited extremely high mass selectivity of SO 2 /CO 2 with a value of 626. The mass absorption capacity was founded to be 1.19 g SO 2 /g DMCHA at 1 atm, which is comparable with the highest reported mass absorption capacity. At low partial pressure, the absorption capacity still reached 0.78 g/g at 0.1 atm, 0.43 g/g at 0.02 atm and 0.27 g/g at 0.001 atm. Furthermore, DMCHA could be completely regenerated in 10 min via microwave heating. All the results indicated this phase-change solution is a promising candidate for SO 2 capture.
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CHEMOSPHERE
·
2018
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IF 4.427
Jiali Peng,Jianfei Yan,Qixuan Chen,Xia Jiang,Gang Yao,Bo Lai
To enhance the degradation of N, N-dimethylacetamide (DMAC) in aqueous solution, the natural mackinawite (NM) is introduced for catalytic ozonation in this study as it is an environmentally friendly catalyst with low cost and easy availability. The properties of the NM were initially characterized via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Then, impact factors including NM dosage, ozone gas concentration and initial pH were investigated and the optimal conditions (i.e., NM dosage = 3.5 g/L, ozone gas concentration = 300 L/min, initial pH = 6.8) were obtained in NM/O3 process. Besides, the superiority of the NM/O 3 process was confirmed by the experiments that the degradation efficiency of DMAC in the NM/O 3 process (i.e., 95.4%) was much higher than that in the zero-valent iron (ZVI)/O 3 process (i.e., 46.1%) and the synthetic FeS/O 3 process (i.e., 68.6%). Furthermore, the intermediate and possible degradation pathway of DMAC were proposed, and the biological toxicity of the intermediate was subsequently evaluated by the activated sludge . Finally, the mechanism of the NM/O3 process was proposed in this study based on control experiment and radical scavenging experiment. The extraordinary efficiency for DMAC degradation was found to be mainly caused by HO • of the reactive oxygen species (ROS) (i.e., HO • , O 2 •- and H 2 O 2 ) generated in the NM/O 3 process. Therefore, this study confirmed that NM was a high efficient catalyst for degradation the toxic and refractory pollutants in catalytic ozonation system.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 29
·期 24
·20959-20967
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IF 2.324
Wu Xiang-Feng,Zhang Chen-Xu,Wang Yu-Duan,Su Jun-Zhang,Zhang Jia-Rui,Feng Yan-Mei,Zhang Mi,Tong Xin,Zhang Wei-Guang,Sun Xiu-Guo
The Ag 2 CrO 4 /SnO 2 n–n type heterojunction has been fabricated by coupling Ag 2 CrO 4 particles with SnO 2 nanorods via an in situ synthetic method. The photocatalytic degradation mechanism of the as-prepared heterojunction has also been discussed. Characterization results revealed that the as-fabricated Ag 2 CrO 4 /SnO 2 composites could reinforce the photo-degradation competencies for rhodamine B dilute solution compared to pure Ag 2 CrO 4 and SnO 2 samples. As the increase in the molar ratios of Ag 2 CrO 4 –SnO 2 , the photocatalytic degradation efficiency appeared to the tendency of first increasing and then decreasing. When it was 4:10, in 90 min, the as-obtained samples possessed the vintage photocatalytic degradation efficiency of 95.8% among of pure SnO 2 , Ag 2 CrO 4 and the as-prepared composites with various molar ratios, respectively. Furthermore, the Ag 2 CrO 4 and SnO 2 were connected via chemical bonds to form the homogenous heterojunction. It could boost the separation and transfer of the photogenerated holes and electrons. In addition, the holes, hydroxyl and superoxide radicals played a major role during the photodegradation process.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2015
·Vol. 54
·期 8
·1036-1043
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IF 3.113
Xueteng Cao,Daniel Horák,Zesheng An,Zdeněk Plichta
Nonspecific interaction is a key parameter affecting the efficiency of proteins, nucleic acids or cell separation. Currently, many approaches to introduce antifouling properties to materials have been developed. Among these, surface modification with polymer brushes plays a prominent role. The aim of this study was to synthesize new magnetic microspheres grafted with poly( N,N -dimethylacrylamide) (PDMA) that resist nonspecific protein adsorption. Monodisperse macroporous poly(2-hydroxyethyl methacrylate) (PHEMA) microspheres, 4 μm in size, were synthesized by a multiple swelling polymerization method. To render the microspheres magnetic, iron oxide was precipitated inside the microsphere pores. Functional carboxyl groups, introduced by the hydrolysis of the 2-(methacryloyl)oxyethyl acetate (HEMA-Ac) comonomer, were used to react with propargylamine, followed by coupling of a chain transfer agent via an azide-alkyne click reaction. PDMA was grafted from the PHEMA microspheres using reversible addition-fragmentation chain transfer polymerization (RAFT), resulting in surfaces with more than 81 wt % PDMA attached. The successful modification of the microspheres was confirmed by XPS. The magnetic microspheres grafted with PDMA showed excellent antifouling properties as tested in bovine serum protein solutions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54 , 1036–1043
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JOURNAL OF MATERIALS RESEARCH
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2014
·Vol. 29
·期 18
·2170-2178
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IF 1.815
Xiaomeng Lü,Jiayu Shen,Ziwei Wu,Jiaxi Wang,Jimin Xie
Plasmonic Ag nanoparticles (AgNPs) with narrow distribution were successfully loaded on graphitic carbon nitride (g-C3N4) sheet by thermal polymerization of melamine precursor and a simple wet-chemical pathway in the presence of polyvinylpyrrolidone (PVP). N,N-dimethylformamide (DMF) was used as an efficient reducing agent as well as a solvent and its presence facilitated homogeneous distribution of AgNPs under mild reaction condition and easy control of its particle growth under different precursor amounts. Ag/g-C3N4 composites of different Ag content were prepared, and the phase, chemical structure, morphologies, electronic and optical properties of Ag/g-C3N4 heterostructures were well characterized, respectively. The photocatalytic activity of Ag/g-C3N4 composites was evaluated by the decolorization of methyl orange (MO), and they exhibited superior photocatalytic activity to bulk g-C3N4 under visible-light irradiation. Influence of Ag content to photocatalytic activity was also discussed and possible mechanism was explored based on the analysis of photoluminescence spectra (PL) and photodecoloration activity.
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MOLECULAR PHARMACEUTICS
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2014
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IF 4.787
Yanping Li,Yangyang Zhou,Bowen Qi,Tao Gong,Xun Sun,Yao Fu,Zhirong Zhang
Parkinson’s disease (PD) has become one of the most deadly diseases due to a lack of effective treatment. Herein, N-3,4-bis(pivaloyloxy)dopamine-3-(dimethylamino)propanamide (PDDP), a brain-specific derivative of dopamine, was designed and synthesized, which consists of a brain targeted ligand, N,N-dimethyl amino group, and two dipivaloyloxy groups for lipophilic modification. PDDP was investigated both in vitro and in vivo by comparing with L-DOPA and another derivative (BPD) without N,N-dimethyl amino group. PDDP showed a more pronounced accumulation in mouse brain microvascular endothelial cells (bEnd.3) than BPD via an active transport process. The increased cellular uptake of PDDP was proven to be mediated by putative pyrilamine cationic transporters. Following intravenous administration, the concentration of PDDP in the brain was 269.28-fold and 6.41-fold higher than that of L-DOPA and BPD at 5 min, respectively. Additionally, PDDP effectively attenuated the striatum lesion caused by 6-hydroxydopamine (6-OHDA) in rats. More importantly, PDDP presented antioxidant and antiapoptotic effects on 6-OHDA-induced toxicity in human neuroblastoma cells (SH-SY5Y). Thus, N,N-dimethyl amino group-based PDDP represents an effective and safe treatment for PD.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2015
·
IF 2.037
Chunlin Li,Qinbo Wang,Binwei Shen,Zhenhua Xiong,Chuxiong Chen
The mole fraction solubilities of 5,10,15,20-tetraphenylporphyrin (TPP) and 5,10,15,20-tetra(p-chlorophenyl)porphyrin (p-ClTPP) in binary system N,N-dimethylformamide (DMF) + water solvent mixtures were measured at atmospheric pressure by using the static method. The temperature and effects of mole fraction of DMF in the solvent mixtures on solubility were studied. The results show that the solubilities of TPP and p-ClTPP increase with the increasing temperature for a certain solvent composition, and the solubilities show a maximum in pure DMF, then the solubilities decrease when the water was added to the system. The experimental data were correlated with modified Apelblat equation. The solubilities calculated by the model were in good agreement with experimental observations. Thermodynamic parameters such as dissolution enthalpy, isobaric heat capacity and Gibbs energy were obtained from the solubility data by using the Clark–Glew equation together with the modified Apelblat equation. The result demonstrated that the dissolving process of TPP and p-ClTPP in DMF + water solvent mixtures is endothermic and not spontaneous.
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JOURNAL OF SEPARATION SCIENCE
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2013
·
IF 2.591
Jing Chen,Juan Zhang,Wenpeng Zhang,Zilin Chen
Sarcosine, a potential biomarker of prostate cancer, has drawn great attention in recent years. However, controversial research keeps arising about its role as a biomarker that might come from the two isomers (α-alanine and β-alanine) of sarcosine due to their same molecular weight and similar properties, which could interfere with the accurate detection of sarcosine. In this study, a simple and sensitive method was developed for the detection of sarcosine and the two isomers by LC with ion-trap MS through a novel derivatization reagent N , N ′-dicyclohexylcarbodiimide. N , N ′-Dicyclohexylcarbodiimide is usually considered as a condensation reagent, however, it was directly used as a derivatization reagent through a rearrangement side reaction in this study. The proposed method not only improved the chromatographic retention behavior of sarcosine and its two isomers, which was a benefit to their separation, but also dramatically enhanced the detection sensitivity of sarcosine, which was more favorable for real sample analysis. The factors affecting the productivity of the derivatization reaction, such as reaction time and amount of derivatization reagent, were systematically optimized. The method shows good linearity ( R 2 > 0.99), sensitivity with LODs of sarcosine as low as 1 ng/mL, and repeatability with the RSD < 6.07%. The developed method was applied to the analysis of urine.
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International Journal of Nanomedicine
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2013
·
IF 3.463
Xiao-juan Hu,Yang Liu,Xiao-feng Zhou,Qiao-ling Zhu,Yong-yan Bei,Ben-gang You,Chun-ge Zhang,Wei-liang Chen,Zhou-li Wang,Ai-jun Zhu,Xue-nong Zhang,Yu-jiang Fan
Novel amphiphilic chitosan derivatives (N-caprinoyl-N-trimethyl chitosan [CA-TMC]) were synthesized by grafting the hydrophobic moiety caprinoyl (CA) and hydrophilic moiety trimethyl chitosan to prepare carriers with good compatibility for poorly soluble drugs. Based on self-assembly, CA-TMC can form micelles with sizes ranging from 136 nm to 212 nm. The critical aggregation concentration increased from 0.6 mg • L −1 to 88 mg • L −1 with decrease in the degree of CA substitution. Osthole (OST) could be easily encapsulated into the CA-TMC micelles. The highest entrapment efficiency and drug loading of OST-loaded CA-TMC micelles(OST/CA-TMC) were 79.1% and 19.1%, respectively. The antitumor efficacy results show that OST/CA-TMC micelles have significant antitumor activity on Hela and MCF-7 cells, with a 50% of cell growth inhibition (IC50) of 35.8 and 46.7 μg. mL −1 , respectively. Cell apoptosis was the main effect on cell death of Hela and MCF-7 cells after OST administration. The blank micelles did not affect apoptosis or cell death of Hela and MCF-7 cells. The fluorescence imaging results indicated that OST/CA-TMC micelles could be easily uptaken by Hela and MCF-7 cells and could localize in the cell nuclei. These findings suggest that CA-TMC micelles are promising carriers for OST delivery in cancer therapy.
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