CHEMOSPHERE
·
2021
·
IF 7.086
Yi Sun,Qingxiang Zhou,Xueying Sheng,Shuanying Li,Yayan Tong,Jinghan Guo,Boyao Zhou,Jingyi Zhao,Menghua Liu,Zhi Li,Yanhui Li,Tongxu Qu,Chunmao Chen
4-Carboxyphenylboronic acid was used as the single precursor to facilely prepare fluorescent carbon quantum dots by one-step solvothermal method. The as-obtained carbon dots (CDs) exhibited highly selective and sensitive for benzo[a]pyrene (BaP), and may be a splendid sensor for sensing BaP. The principle was that the as-prepared CDs could form a complex with BaP through hydrophobic interaction which causes the decrease of fluorescence intensity of CDs by static quenching principle. The constructed fluorescent sensor exhibited excellent linearity ranged from 0.002 to 0.06 μg mL −1 and provided a low limit of detection of 0.16 ng mL −1 . The experimental results showed that this fluorescent sensor resulted in simplicity, rapidness, low cost, short analytical time, and high sensitivity and stability. Validation with real water samples endowed the sensor high reliability and feasibility for BaP determination in practical application in various samples.
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PLoS One
·
2021
·Vol. 16
·期 4
·e0249915
·
IF 3.24
Jing Han,Ze-Tian Qin,Jing Zhang,Wen-Qiang Wang,Jing-Ya Wu,Yong-Ze Lu,Li-Wei Sun
Ultraviolet (UV) filters are used in cosmetics, personal care products and packaging materials to provide sun protection for human skin and other substances. Little is known about these substances, but they continue to be released into the environment. The acute toxicity of 4,4’-dihydroxybenzophenone, 2,4,4’-trihydroxybenzophenone and 4-MBC to Chlorella vulgaris and Daphnia magna were analyzed in this study. The 96 h-EC 50 values of 4,4’-dihydroxybenzophenone, 2,4,4’-trihydroxybenzophenone and 4-MBC on C . vulgaris were 183.60, 3.50 and 0.16874 mg/L, respectively. The 48 h-LC 50 of 4,4’-dihydroxybenzophenone, 2,4,4’-trihydroxybenzophenone and 4-MBC on D . magna were 12.50, 3.74 and 0.54445 mg/L, respectively. The toxicity of a mixture of 4,4’-dihydroxybenzophenone and 4-MBC showed addictive effect on C . vulgaris , while the toxicity of mixtures of 4,4’-dihydroxybenzophenone and 2,4,4’-trihydroxybenzophenone, 2,4,4’-trihydroxybenzophenone and 4-MBC as well as 4,4’-dihydroxybenzophenone, 2,4,4’-trihydroxybenzophenone and 4-MBC all showed antagonistic effect on C . vulgaris . The induced no-effect concentrations of 4,4’-dihydroxybenzophenone, 2,4,4’-trihydroxybenzophenone and 4-MBC by the assessment factor (AF) method were 0.0125, 0.00350 and 0.000169 mg/L, respectively.
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BIOTECHNOLOGY AND APPLIED BIOCHEMISTRY
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2021
·Vol. 69
·期 4
·1428-1437
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IF 2.431
Di Liu,Linbo Gou,Yajun Bai,Tai-Ping Fan,Xiaohui Zheng,Yujie Cai
In this study, the 3-quinuclidinone reductase from Agrobacterium tumefaciens (AtQR) was modified by site-directed mutagenesis. And we further obtained a saturation mutant library in which the residue 197 was mutated. A single-point mutation converted the wild enzyme that originally had no catalytic activity in reduction of ethyl 4-chloroacetoacetate (COBE) into an enzyme with catalytic activity. The results of enzyme activity assays showed that the seven variants could asymmetrically reduce COBE to ethyl ( S )-4-chloro-3-hydroxybutyrate (( S )-CHBE) with NADH as coenzyme. In the library, the variant E197N showed higher catalytic efficiency than others. The E197N was optimally active at pH 6.0 and 40°C, and the catalytic efficiency ( k cat / K m ) for COBE was 51.36 s –1 ·mM –1 . This study showed that the substrate specificity of AtQR could be changed through site-directed mutagenesis at the residue 197.
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JOURNAL OF THE CHINESE CHEMICAL SOCIETY
·
2020
·Vol. 68
·期 4
·582-591
·
IF 1.554
Changzhou Chen,Peng Liu,Haihong Xia,Minghao Zhou,Jianchun Jiang
There is an urgent need to develop a selective hydrogenolysis of C aryl -O bonds in lignin to produce valued-added chemicals and fuels. Recently, hydrogen has been used in the hydrogenation reaction, which hides inevitable danger and is not economical. Therefore, isopropanol, as a hydrogen-donor solvent, is employed for aryl ether hydrogenolysis in lignin models over nickel supported on a carbon nanotube (CNT). Except for aromatic ether (4-O-5), the Ni/CNT catalyst is also found to be suitable for alkyl-aryl ether (α-O-4 and β-O-4) cleavage in control experiments. The physicochemical characterizations were carried out by means of H 2 -temperature-programmed reduction, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses. The catalyst can be magnetically recovered and efficiently reused for five consecutive recycling tests in the transfer hydrogenation of aromatic ethers. A mechanism study indicated that the hydrogenolysis cleavage of the ether bond is the first step in the reaction process, and hydrogenation of aromatic rings is only a successive step in which phenol and benzene are intermediate states and are then further hydrogenated. Furthermore, it has been demonstrated that aryl groups play an important role in the hydrogenation of phenol in the competitive catalytic hydrogenation reaction of phenol.
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ANALYTICA CHIMICA ACTA
·
2021
·
IF 6.558
Lvxia Zhang,Hui Ouyang,Dan Zhang,Zhifeng Fu
Novel cobalt-based metal-organic frameworks (Co MOFs) were synthesized by a facile “controlled synthesis” strategy. The MOFs displayed superior catalytic performance on the chemiluminescent (CL) reaction between N -(4-aminobutyl)- N -ethylisoluminol (ABEI) and H 2 O 2 . UV–vis absorption, CL spectrum, ESR, and radical scavenger experiments were conducted for clarifying the catalytic mechanism of Co MOFs. All results revealed that Co MOFs can accelerate decomposition of H 2 O 2 and production of OH • , O 2 • − as well as 1 O 2 radicals. The rapid reaction between these reactive oxygen species and ABEI resulted in the generation of ABEI-ox∗. The excited-state oxidation product emitted a very intensive CL signal with a maximal emission wavelength of 430 nm as it returned to the ground state. To explore their application potential in CL assay, Co MOFs were used as powerful CL reaction catalyst for establishing a very sensitive method for immunoassay of aflatoxin B 1 . The detection range was 0.05–60 ng mL −1 , and the limit of detection was 4.3 pg mL −1 . The result for detecting herbal medicine samples demonstrates the acceptable reliability of the Co MOFs-based CL immunoassay. The proof-of-principle work verifies the application potential of Co MOFs on boosting intensive CL signal, and meets the demand for high sensitivity in various bioassay fields.
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ACS Applied Energy Materials
·
2020
·
IF 4.473
Yiming Wang,Yanchun Yang,Chengjun Zhu,Hongmei Luan,Ruijian Liu,Lei Wang,Chenxi Zhao,Xiaogong Lv
Substitution of Zn with Mg has been reported to suppress CuZn defects, which can improve the photoelectric performance of Cu2ZnSn(S,Se)4 (CZTSSe) photovoltaic devices. In our work, the electrical property enhancement of an absorbing layer can be found by incorporating Mg content into the as-prepared precursor solution, forming an alloyed Cu2MgxZn1-xSn(S,Se)4 (CMZTSSe) phase and increasing the photoelectric performance of devices. By adjusting the doping ratio of Mg, we systemically study the impact of Mg content on the crystal structure, thickness, and electrical properties of the Cu2MgxZn1-xSn(S,Se)4 absorbing layer. Also, the photoelectric performance of Cu2MgxZn1-xSn(S,Se)4 solar cells have a large improvement, and the optimal photoelectric conversion efficiency (PCE) of 7.76% for devices is obtained. Our results offer the finding that Mg doping can optimize the electrical properties of Cu2ZnSn(S,Se)4 photovoltaic devices.
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INTERNATIONAL IMMUNOPHARMACOLOGY
·
2020
·
IF 3.943
Dan Li,Jiangping Xu,Yunyun Qin,Ningbo Cai,Yufang Cheng,Haitao Wang
Roflupram (ROF) is a novel phosphodiesterase 4 inhibitor. We previously found that ROF suppressed the production of pro-inflammatory factors in microglial cells; however, the underlying mechanisms are largely unknown. The present study aimed to elucidate the underlying molecular mechanisms of the anti-neuroinflammatory effects of ROF in lipopolysaccharide (LPS)-activated microglial cells and LPS-challenged mice. Treatment with ROF suppressed LPS-induced expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α in BV-2 microglia cell line. Immunofluorescence and Western blotting analysis showed that ROF significantly inhibited the activation of microglia, as evidenced by decreased expression of ionized calcium binding adaptor molecule-1 (Iba1). Similar results were obtained in primary cultured microglial cells. ROF induced the phosphorylation of AMP-activated protein kinase (AMPK) and the expression of Sirtuin 1 (Sirt1). Interestingly, the AMPK inhibitor, compound C, blocked the role of ROF in both the phosphorylation of AMPK and the expression of Sirt1 in BV-2 cells stimulated with LPS. More importantly, the Sirt1 inhibitor, EX527, abolished the inhibitory role of ROF on the production of pro-inflammatory factors, and reactivated BV-2 cells. In mice challenged with LPS, ROF improved cognition and decreased the levels of IL-6 and TNF-α in both the cortex and hippocampus. In contrast, EX527 weakened the effects of ROF on cognitive enhancement and reduction of pro-inflammatory factors in the cortex and hippocampus. Furthermore, EX527 blocked the inhibitory role of ROF in the activation of microglial cells in both the hippocampus and cortex. Taken together, our results indicated that ROF attenuated LPS-induced neuroinflammatory responses in microglia, and the AMPK/Sirt1 pathway is essential for the anti-inflammatory effects of ROF.
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CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Zezhou Lin,Tianyu Li,Qian Yu,Haiyun Chen,Di Zhou,Ning Li,Chunyan Yan
Achyranthes bidentata is a species of flowering plant that is mainly distributed in China. The A. bidentata rhizome is a famous traditional Chinese medicine that has been widely used to treat lumbago, arthritis, and bone hyperplasia. In this work, A. bidentata rhizome was isolated and purified to obtain a pectic polysaccharide (ABPB-4). Chemical and spectral analyses showed that ABPB-4 had a main chain of →4)- α - d -Gal p A-(1→ and →2,4)- α - l -Rha p -(1→, and the branch chains included →4)- β - d -Gal p -(1→, →6)- β - d -Gal p -(1→, →3,6)- β - d -Gal p -(1→, →5)- α - l -Ara f -(1→ and →3,5)- α - l -Ara f -(1→, and it was terminated with α - l -Ara f -(1→ and β - d -Gal p -(1→. At concentrations of 0.01, 0.02, and 0.04 μmol/L, ABPB-4 significantly promotes the proliferation, differentiation, and mineralization of MC3T3-E1 cells in vitro , and it appreciably enhances the mRNA expression levels of osteogenic-related genes in these cells. Overall, the results reported herein indicate that ABPB-4 has outstanding osteogenic activity, and that it may be used as an anti-osteoporosis agent in the future.
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CHEMOSPHERE
·
2020
·
IF 5.778
Ping Li,Yixing Wang,Hairong Huang,Shuai Ma,Hu Yang,Zhen-liang Xu
Catalytic membrane plays an important role in environmental remedy. In this study, we reported an Ag coated membrane (PAN-Si-Cu-Ag) with a high catalytic activity to reduce 4-nitrophenol (4-NP) and methyl orange (MO) from water. The best performance is 99% reduction degree and 280 L m −2 .h −1 .bar −1 flux for (4-NP) reduction at 4-NP: NaBH 4 = 1:50 (mM) during a 12-h filtration. The reduction degree for MO is above 90% and the flux is about 230 L m −2 ·h −1 ·bar −1 , which is almost the best report till now. The Ag coated membrane was prepared by metal displacement-epitaxial growth on silica covalent grafted PAN membrane (PAN-Si). Silica atoms were used as linker to ensure the good adhesion between polymer and metal NPs, the loss amount of Ag NPs from the coated catalytic membrane is loss about 2 μg/cm 2 after one month storage. Cheap metal NPs were firstly reduced on the surface of PAN-Si membrane and then used to displace Ag ions. Thus the obtained catalytic membrane showed a very high loading (28%). Finally, the catalytic filtration mechanism of 4-NP was distinguished by Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and adsorption measurement.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2020
·Vol. 413
·期 3
·813-820
·
IF 3.637
Dou Nannan,Qu Jianying
In this work, a hybrid of multiwalled carbon nanotubes, nanogold, and reduced graphene (rGO/AuNPs/MWCNTs) was synthesized rapidly with an easy method, and then combined with chitosan (CS), which was fixed on a glassy carbon electrode (GCE) to construct a new kind of electrochemical sensor to simultaneously determine 4-aminophenol (4-AP) and acetaminophen (AC). When detecting 4-AP and AC simultaneously, the linear range is 0.12~12 μM for acetaminophen and 0.05~25 μM for 4-aminophenol; the detection limit is 42 nM for acetaminophen and 2.95 nM for 4-aminophenol. Compared with previously related reports, the proposed sensor has an excellent electrocatalytic performance for the redox of 4-AP and AC, which can effectively determine 4-AP and AC simultaneously in actual samples and has potential application prospect.
Graphical abstract
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CRYSTAL GROWTH & DESIGN
·
2020
·
IF 4.089
Taolian Guo,Chao Wang,Nannan Zhang,Yan Zhang,Tian Chen,Xing Xing,Zhenda Lu,Lili Wen
Compared with noble metal nanoparticles (MNPs), non-noble MNPs possess obvious advantages owing to their abundant reserves on the earth and low cost. Therefore, the synthesis of small and highly active non-noble MNPs is desirable in practice. With the merits of metal–organic framework (MOF) nanosheets, we develop a novel and facile in situ reduction strategy for the incorporating of ultrasmall and homogeneous Ni NPs within NMOF-Ni, where the self Ni(II) metal ion nodes are partly reduced to metallic Ni(0) atoms by the reducing agent of aqueous NaBH4 under ambient conditions. The as-synthesized Ni/NMOF-Ni-0.4 behaves as an ideal catalyst for the catalytic reduction of 4-nitrophenol, with high efficiency and selectivity as well as good recyclability, arising from the ultrasmall and monodisperse Ni NPs, as well as 2D MOF nanosheet carriers. Strikingly, the straightforward strategy has been successfully applicable to fabricating Co/NMOF-Co-0.4, illustrating that the in situ reduction method might be facile and effective for producing MNPs/MOFs. This work represents a rare report about fabrication of MNPs/MOFs based on an in situ reduction approach without impregnation of additional metal precursors.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2020
·
IF 4.192
Jingming Wang,Na Zhang,Minyue Zhao,Tingting Jing,Jieyang Jin,Bin Wu,Xiaochun Wan,Wilfried Schwab,Chuankui Song
The carotenoid-derived volatile β-ionone plays an important role in the formation of green and black tea flavors due to its low odor threshold, but its formation and the gene(s) involved in its biosynthesis during the tea withering process is(are) still unknown. In this study, we found that the content of β-ionone increased during the tea withering process catalyzed by an unknown enzyme(s). Correlation analysis of expression patterns of Camellia sinensis carotenoid cleavage dioxygenase genes (CsCCDs) and the β-ionone content during the withering period revealed CsCCD4 as the most promising candidate. The full-length CsCCD4 gene was amplified from C. sinensis, and the biochemical function of the recombinant CsCCD4 protein was studied after coexpression in Escherichia coli strains engineered to accumulate β-carotene. The recombinant protein was able to cleave a variety of carotenoids at the 9–10 and 9′–10′ double bonds. Volatile β-ionone was detected as the main product by gas and liquid chromatography–mass spectrometry. The accumulation of β-ionone was consistent with the expression levels of CsCCD4 in different tissues and during the withering process. The CsCCD4 expression was induced by low temperature and mechanical damage stress but not by dehydration stress. The results demonstrate that CsCCD4 catalyzes the production of β-ionone in the tea plant and provide insight into its formation mechanism during the withering process.
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危险品化学品经营许可证（带存储）