JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2015
·Vol. 53
·期 21
·2469-2480
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IF 3.113
Yong Deng,Xi Wang,Qiulin Yuan,Mengxiang Zhu,Ying Ling,Haoyu Tang
A series of side-chain-functionalized α-helical polypeptides, i.e., poly(γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamic acid-based N -carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via copper-mediated [2+3] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α-helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I − counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures ( T pt s) were dependent on the main-chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53 , 2469–2480
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SENSORS AND ACTUATORS B-CHEMICAL
·
2015
·
IF 4.097
Shaofei Zhang,Hui Yang,Ying Ma,Yu Fang
A bis-nitrobenzoxadiazole (NBD) derivative of calix[4]arene (L 1 ) and a control compound (L 2 ), mono-NBD derivative of the calixarene were designed and prepared via click chemistry. Fluorescence studies demonstrated that L 1 as created can function as a switch with the presence of Ag + in THF, of which the free state of L 1 emits at ∼527 nm, but the binding state at 576 nm. Based upon this discovery, L 1 was studied as a chemo-sensor of Ag + in a mixture solvent of THF and H 2 O with a detection limit (DL) of ∼6.2 × 10 −7 mol/L. Presence of other commonly found metal ions shows little effect upon the determination. Moreover, the L 1 in the Ag + -L 1 complex could be fully released with introduction of HCHO, a bases for the sensitive and selective detection of the toxic chemical. The DL of this test is 6.6 × 10 −7 mol/L. Interestingly, binding and releasing of the fluorescent ligand could be repeated for at least 5 times. Furthermore, both sensing could be performed in a visualized manner. It is believed that the fluorescent compound as created should have a potential to find real-life applications.
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POLYMER COMPOSITES
·
2014
·Vol. 36
·期 9
·1597-1605
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IF 1.455
Ruxangul Jamal,Ahmat Ali,Li Zhang,Yakupjan Osman,Adalet Rahman,Tursun Abdiryim
Poly(3′,4′-ethylenedioxy-2,2′:5′,2″-terthiophene)/ZnO(poly(TET)/ZnO) composites with the ratio of poly(TET) and nano-ZnO from 3:1 to 1:3 were synthesized by hand grinding and ball milling methods, respectively. The photocatalytic activities of the composites were examined through the degradation processes of methylene blue (MB) solution under UV light irradiation, and the possible mechanism for the photocatalytic activity enhancement by synergetic effects between nano-ZnO and poly(TET) was proposed. The results showed that the strong interactions between the poly(TET) and nano-ZnO occurred in the case of ball milling method. The results also proved that the crystallinity of ZnO was not disturbed in both of methods, and the nano-ZnO was uniformly distributed in polymer matrix in the case of ball milling method. The comparative studies showed that the addition of the nano-ZnO could enhance the photocatalytic activities of the composites. The highest degradation efficiency (100%) at 3 h under UV light irradiation occurred in the case of poly(TET)/ZnO(1:1) synthesized by ball milling method. Furthermore, the nanocompsosite displayed higher photocatalytic activity than nano-ZnO, which was due to the holes ( h + ) transferring from the valence band of ZnO to the polymer backbone and the adsorption of MB molecules in polymer matrix via π–π conjugation between MB and aromatic regions of the poly(TET). POLYM. COMPOS., 36:1597–1605, 2015. © 2014 Society of Plastics Engineers
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Scientific Reports
·
2017
·Vol. 7
·期 1
·1-11
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IF 4.259
Huang Haiying,Tao Xuanyu,Jiang Yiming,Khan Aman,Wu Qi,Yu Xuan,Wu Dan,Chen Yong,Ling Zhenmin,Liu Pu,Li Xiangkai
Soil contamination by PAH and heavy metals is a growing problem. Here, we showed that a new isolate, Pseudomonas brassicacearum strain LZ-4, can simultaneously degrade 98% of 6 mM naphthalene and reduce 92.4% of 500 μM hexavalent chromium [Cr (VI)] within 68 h. A draft genome sequence of strain LZ-4 (6,219,082 bp) revealed all the genes in the naphthalene catabolic pathway and some known Cr (VI) reductases. Interestingly, genes encoding naphthalene pathway components were upregulated in the presence of Cr (VI), and Cr (VI) reduction was elevated in the presence of naphthalene. We cloned and expressed these naphthalene catabolic genes and tested for Cr (VI) reduction, and found that NahG reduced 79% of 100 μM Cr (VI) in 5 minutes. Additionally, an nahG deletion mutant lost 52% of its Cr (VI) reduction ability compared to that of the wild-type strain. As nahG encodes a salicylate hydroxylase with flavin adenine dinucleotide (FAD) as a cofactor for electron transfer, Cr (VI) could obtain electrons from NADH through NahG-associated FAD. To the best of our knowledge, this is the first report of a protein involved in a PAH-degradation pathway that can reduce heavy metals, which provides new insights into heavy metal-PAH contamination remediation.
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ANALYTICAL SCIENCES
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2017
·Vol. 33
·期 7
·793-799
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IF 1.228
Wang Yan,Huang Bin-Bin,Dai Wan-Lin,Xu Bin,Wu Tian-Liang,Ye Jia-Ping,Ye Jian-Shan
A sensitive capsaicin sensor was constructed based on a poly(sodium 4-styrenesulfonate) functionalized graphite modified screen printed electrode (PSS-Grp/SPE) in this study. The PSS-Grp and poly(diallyldimethylammonium chloride) functionalized graphite (PDDA-Grp) were easily synthesized by interacting Grp with PSS and PDDA through sonication, and resulted in negative and with positive charges on the surface, respectively. The prepared PSS-Grp and PDDA-Grp were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet and visible spectroscopy (UV-vis). The electrochemical performance of PSS-Grp in a 50 μM capsaicin solution presented a current density of 33 μA cm –2 , which was much higher than the PDDA-Grp of 1.5 μA cm –2 . Our study showed that capsaicin could interact better with strong negative charges on the PSS-Grp/SPE surface to give a higher electrochemical response. The direct electrochemical sensing of capsaicin was achieved at PSS-Grp/SPE using differential pulse stripping voltammetry (DPSV) under the optimized conditions.
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CRYSTENGCOMM
·
2017
·Vol. 19
·期 37
·5686-5691
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IF 3.474
Zhao Huang,Kai Cai,Huan Zhang,Zilan Hong,Zhaodong Yuan,Heyou Han
A facile method for the synthesis of Au-pearl/Pd-wire heterostructured nanonecklaces (APHNs) was developed for the first time, in which regular Au pearls with controllable size and interval distance were interlinked into a string by an ultrathin and ultralong Pd nanowire. The distribution density of Au nanopearls was regulated by the concentration of the reducing agent, while their size was controlled by the amount of the Au precursor. In the study of degradation of 4-nitrophenol (4-NP), the catalytic properties of several typical APHNs are proved to be inherently related to their morphology. By comparison with other nanostructures and commercial Pd/C, the APHNs show superior catalytic activities and better stability in general. The study demonstrated that novel heterostructures have superior catalytic properties in the degradation of 4-NP. Moreover, the nanostructures have the potential to be used as a high-efficiency catalyst in other catalytic reactions.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2016
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IF 3.652
Qiang Lu,Zhi-bo Zhang,Xiao-ning Ye,Wen-tao Li,Bin Hu,Chang-qing Dong,Yong-ping Yang
A new technique was proposed to selectively produce 4-ethyl guaiacol (4-EG), a valuable phenolic compound, via low-temperature catalytic fast pyrolysis of softwood biomass using the Pd/SBA-15 catalyst. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to compare 4-EG production from three biomass materials with different lignin types (pine wood, poplar wood and bagasse) and two catalytic patterns (in-situ and ex-situ). Further experiments were performed to reveal 4-EG formation affected by the pyrolysis temperature, catalyst-to-biomass ratio and Pd content of the Pd/SBA-15 catalyst. The results indicated that 4-EG could be selectively produced from pine wood by the in-situ catalytic pattern. 4-EG was a very minor pyrolytic product in the non-catalytic process, while it could be selectively produced in the catalytic process, via the decomposition and hydrogenation of lignin. Our results suggested that several holocellulose-derived pyrolytic products could serve as the hydrogen-donors (H-donors) for the formation of 4-EG, without any extra H-donors. The highest 4-EG yield of 18.44 mg/g from pine wood was obtained at the temperature of 350 °C and catalyst-to-biomass ratio of 2, and the corresponding peak area% (calculated by GC/MS) was 38.34%.
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2017
·
IF 2.726
Hui Ding,Wenjing Ke,Dan Zhao,Lulu Wang,Yujie Gao,Shejiang Liu
In this work, we measured the isobaric vapor-liquid equilibrium (VLE) data for the binary system of methyl caprate (1) + methyl laurate (2) at 2,4 and 6 kPa with a modified Othmer still. The point consistency test of Van Ness test method was applied to check the thermodynamic consistency of all the experimental values, which guaranteed the reliability of our measurements. Afterwards, the experimental data were regressed by two activity coefficient models (Wilson, NRTL). Furthermore, we made the data prediction with the group contribution method (UNIFAC) and the COSMO-SAC model. The results of all the regressions and predictions are satisfying and reasonable, while the results provided by the NRTL model are relatively better than the other three models, with the root mean square deviations of temperature and vapor-phase mole fraction less than 0.33 K and 0.0069, respectively.
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Analytical Methods
·
2017
·Vol. 9
·期 17
·2517-2522
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IF 1.9
Chenmeng Zhang,Xiu Liang,Tingting You,Nan Yang,Yukun Gao,Penggang Yin
An ultrasensitive “turn off” Surface Enhanced Raman Spectroscopy (SERS) sensor was developed for the detection of heparin based on the anti-aggregation of 4-mercaptobenzoic acid stabilized gold nanoparticles. In this paper, protamine, a small protein molecule with positive charges, could induce the aggregation of 4-MBA functionalized gold nanoparticles via surface electrostatic interaction. However, in the presence of heparin, the aggregation of 4-MBA functionalized gold nanoparticles decreased due to the fact that heparin has a strong affinity toward protamine, further causing the loss of the Raman enhanced effect. The normalized SERS intensity of the Raman reporter was proportional to the concentration of added heparin and a good linear detection range was obtained from 0.05 to 20 ng mL−1 (R2 = 0.999) with a calculated detection limit of 0.03 ng mL−1. Moreover, the developed highly selective method is also successfully demonstrated in fetal bovine serum. Our method is specific, simple and cheap, which could be applied to other further research studies of heparin.
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MICROCHIMICA ACTA
·
2024
·Vol. 191
·期 5
·1-9
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IF 5.3
Yan Qinghua,Wu Ruixue,Wang Jiaxin,Mao Jian,Nan Wenbin
Abstract To accurately detect tumor marker carbohydrate antigen 72-4 (CA72-4) of serum samples is of great significance for the early diagnosis of malignant tumors. In the present study, MnO 2 /hollow nanobox metal-organic framework (HNM)-AuPtPd nanocomposites were prepared via multi-step synthesis and superposition method and a series of characterizations were carried out. A highly sensitive immunosensor Ab/MnO 2 /HNM-AuPtPd/GCE based on the composite nanomaterial was further prepared and used to detect the tumor marker CA72-4. The constructed immunosensor achieved signal amplification by increasing the electrocatalytic activity to H 2 O 2 by means of the synergistic effect of MnO 2 ultra-thin nanosheets (MnO 2 UNs) and HNM-AuPtPd. At the same time, the electrochemical properties of the immunosensor were analyzed using cyclic voltammetry, electrochemical impedance, amperometry (with the test voltage of −0.4 V), and differential pulse voltammetry. The experimental results showed that the MnO 2 /HNM-AuPtPd nanocomposites were successfully prepared, and the immunosensor Ab/MnO 2 /HNM-AuPtPd/GCE demonstrated an excellent electrochemical performance. The electrochemical immunosensor had the highest detection sensitivity under the optimal experimental conditions, such as incubation pH of 7.0, incubation time of 60 min, with the addition of 15 μL of H 2 O 2 , and in the concentration range 0.001–500 U/mL. It had a low detection limit of 1.78×10 −5 U/mL (S/N = 3). Moreover, the serum sample recovery were in the range from 99.38 to 100.52%. This study provides a new method and experimental basis for the detection of tumor markers in clinical practice. Graphical Abstract
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Kai Yang,Zhenjie Tang,Chong Zhang,Ruide Zhang,Sheng Hu,Changjiang Lv,Jun Huang,Jiaqi Mei,Weirui Zhao,Lehe Mei
Salvianic acid A (SAA) is a catechol compound known for its diverse physiochemical functions and has significant applications in the food and pharmaceutical industries. 4-Hydroxyphenylacetate-3-hydroxylase (4HPA3H) is a critical enzyme for SAA biosynthesis, and improving its activity towards p -hydroxyphenyllactate acid (4HPLA) is essential for highly efficient SAA production in stable biosynthetic pathways. To address this, the distal site and loops of the substrate pocket were modified to improve 4HPA3H catalytic activity towards 4HPLA using computer-aided molecular modification methods. As a result, we identified and mutated two critical sites in Ec HpaB, a 4HPA3H monooxygenase from Escherichia coli : T398, a substrate loop site, and M205, a distal site. The mutants M205F, T398S, and M205F/T398S enabled 2.51-, 2.07-, and 2.20-fold increases in catalytic efficiency ( k cat / K m towards 4HPLA), respectively. Molecular dynamics simulations showed that the overall decreased flexibility of the substrate pocket loop in Ec HpaB might help improve the enzyme's catalytic activity for 4HPLA. Owing to the T398 site in the substrate pocket coming from another monomer, molecular modification of Ec HpaB with multi-monomer interactions was also worthy of attention. These findings not only enhanced the biosynthetic efficiency of SAA but also provided insights into enzyme distal site modification and the engineering of multi-monomer enzymes.
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PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2024
·
IF 6.9
Linquan Dai,Bo Feng,Mengyan Tang,Yuangan Chen
It is challenging to separate between molybdenite and chalcopyrite due to their comparable hydrophobic characteristics. Inorganic depressants were previously used to separate two minerals, but the results were unsatisfactory and polluted the environment. In this study, the molybdenite and chalcopyrite were separated using a highly effective and ecologically safe depressant, 2,4-Diamino-6-hydroxypyrimidine (DAHP). According to the single mineral experiment, chalcopyrite is totally depressed while molybdenite has superior floatability. The efficacy of DAHP as the depressant was validated by further artificially mixed mineral flotation experiments, indicating the possibility of separating chalcopyrite and molybdenite. The adsorption capacity experiment results showed that the adsorption capacity of DAHP on the surface of chalcopyrite was greater than that on the surface of molybdenite. Zeta potential experiment results show that DAHP is adsorbed on the surface of chalcopyrite and molybdenite through static electrostatic interactions . X-ray photoelectron spectroscopy (XPS) experiment results show that DAHP is mainly adsorbed on chalcopyrite surface through –NH 3 + group, which hinders the adsorption of kerosene. The electrostatic contact between DAHP and molybdenite has the least effect on kerosene adsorption. This study shows that DAHP has the potential to separate chalcopyrite and molybdenite as an efficient and environmentally friendly depressant.
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危险品化学品经营许可证（带存储）