ATMOSPHERIC ENVIRONMENT
·
2020
·
IF 4.039
Fenghua Li,Shanshan Tang,Narcisse T. Tsona,Lin Du
Kinetics and mechanism of α-terpineol oxidation by OH radicals were studied in the aqueous phase under acidic condition, and the optical properties of the reaction products were examined. Using the relative rate method, the rate constant of α-terpineol reaction with OH radicals was determined to be (1.3 ± 0.3) × 10 10 M −1 s −1 . The reaction products were analyzed by gas chromatography-mass spectrometry (GC-MS) and the reaction mechanism was proposed. The absorbance changes of the products were monitored by a UV–vis spectrophotometer, and α,β-unsaturated ketone compounds were observed. A certain distribution of α-terpineol in the aqueous phase has the potential to be conducive to the formation of aqueous secondary organic aerosols. At the same time, in order to investigate the persistence of α-terpineol in the atmosphere, its lifetime towards reaction with OH in atmospheric water was determined to be 6.2 h and 1.0 h in urban and remote area, respectively.
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BIOMEDICINE & PHARMACOTHERAPY
·
2020
·
IF 4.545
Huanhuan Xu,Litian Wang,Boya Shi,Lihong Hu,Chunxia Gan,Ya Wang,Zemin Xiang,Xuanjun Wang,Jun Sheng
Caffeine (1,3,7-trimethylxanthine) is a xanthine alkaloid found in a number of dietary products consumed worldwide, such as coffee, tea, and soft beverages, and is known to act as a modifying agent for cytotoxic chemotherapeutic drugs. Studies have shown that caffeine reduces the cytotoxic effects of paclitaxel and inhibits paclitaxel-induced apoptosis; however, the underlying mechanism remains unclear. Here, we investigated whether caffeine inhibits the antitumor activity of paclitaxel via down-regulation of α-tubulin acetylation. In vitro studies, involving MTT assay, wound-healing assay, cell apoptosis assay, and western blotting analysis of A549 and HeLa cells, were performed. A549 and HeLa cell-based xenografts were established, and western blotting and immunohistochemical staining were performed for in vivo studies. The results showed that caffeine promoted the growth of cancer cells treated with paclitaxel. Additionally, caffeine enhanced migration ability, inhibited apoptosis, and decreased the acetylation of α-tubulin in paclitaxel-treated cancer cells. Furthermore, caffeine decreased the inhibitory effect of paclitaxel on tumor growth through down-regulation of α-tubulin acetylation in vivo . Taken together, these findings demonstrate that caffeine inhibits the anticancer activity of paclitaxel via down-regulation of α-tubulin acetylation, suggesting that patients receiving treatment with taxanes, such as paclitaxel, should avoid consuming caffeinated beverages or foods.
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CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yadan Luo,Ying Li,Ning Zhang,Yushi Ding,Hongzheng Li,Gang Chen
The effects of bromine (Br) addition on electrical properties and chemical stability of Gd-doped barium cerate proton-conducting electrolyte were investigated. BaCe 0.8 Gd 0.2 O 2.8±δ Br 0.2 (BCGBr) and BaCe 0.8 Gd 0.2 O 3-α (BCG) powders with CuO as sintering aid were obtained via a solid-state reaction. The results of X-ray fluorescence (XRF) confirm that only trace amounts of Br are present in BCGBr after high temperature sintering at 1600 °C, indicating that Br addition influences stoichiometry but not directly the physicochemical properties. Nevertheless, the XRD results from the treated BCGBr and BCG electrolyte pellets show that the chemical stability of BCGBr in water and/or CO 2 -containing atmospheres is conspicuously improved. The conductivities of electrolyte sintered at 1600 °C for 10 h were investigated in various atmospheres by AC impedance technique. The total conductivity ( σ t o t ) of BCGBr under wet Ar is lower than that of BCG. Partial-conductivities components ((proton ( σ OH O · ), oxygen ion ( σ V O · · ), and hole ( σ h · )) are presented for BCGBr according to the defect structure model. The results show that the proton conductivity of BCGBr remains nearly constant over the 550–750 °C temperature range. Although σ t o t of Br-synthesized sample slightly decreases, the BCGBr exhibits a high σ OH O · (0.058 S cm −1 at 750 °C) under pH 2 O = 0.038 atm and pO 2 = 1 atm. P-type and oxygen ion conduction are dominant in an oxidative atmosphere (pO 2 = 1 atm) at 650 °C. Under low oxygen conditions (pO 2 = 10 −4 atm), BCGBr shows the behavior of mixed conduction (oxygen ions ( V O · · ) and protons ( OH O · )). Besides, the main carriers in BCGBr oxide change from OH O · to V O · · as temperature increased.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 8
·1-9
·
IF 6.232
Hu Xuemei,Wei Zixuan,Sun Chaoqun,Long Yijuan,Zheng Huzhi
Cu 2+ are found to greatly reduce the photoinduced oxidase activity of fluorescein and then inhibit the chromogenic reaction catalyzed by fluorescein. A simple colorimetric assay for Cu 2+ is established. Based on this, bifunctional nanocomposites of α-fetoprotein (AFP) antibody (Ab) and copper-based metal-organic framework (Ab2@Cu-MOF) are synthesized by the simple self-assembly of AFP Ab2, Cu 2+ , and 4,4′-dipyridyl: the binding site of AFP Ab2 exposed on the surface of the nanocomposites can specifically recognize AFP antigen; Cu 2+ in nanocomposites can inhibit the visible light-induced activity of fluorescein. The structure of Ab2@Cu-MOF disintegrate and Cu 2+ is released in an acetate buffer solution. The higher the amount of AFP antigens, the more significant the inhibitory effect. Thus, the Ab2@Cu-MOF immunoassay for AFP determination is established using 3,3′,5,5′-tetramethylbenzidine as chromogenic substrate with a detection limit of 35 pg.mL −1 . This simple, cheap, and sensitive method sheds substantial light on practical clinical diagnosis. Meanwhile, the mechanism of inhibition is revealed to facilitate the targeted selection of enzyme regulators.
Diagrammatic illustration of Cu 2+ detection (part a) and Ab2@Cu-MOF immunoassay for sensing α-fetoprotein based on the synthesized Ab2@Cu-MOF nanocomposites (parts a and b).
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Chunyu Sun,Xinzhan Wang,Yanmei Xu,Wanbing Lu,Xiaoyun Teng,Guangsheng Fu,Wei Yu
CsPbI 3 nanocrystals (NCs) with photoluminescence quantum yield (PLQY) larger than 90% have been synthesized at different temperature regions, and the physical origins for high PLQY were investigated. HRTEM images show that cubic phase CsPbI 3 (α-CsPbI 3 ) is surrounded by hexagonal Cs 4 PbI 6 in the low temperature region, and the ratio of CsPbI 3 and Cs 4 PbI 6 increases with increasing the reaction temperature. The strong confinement effect of Cs 4 PbI 6 leads to the high PLQY (95%) of α-CsPbI 3 NCs when the reaction temperature is 120 °C. The confinement effect of Cs 4 PbI 6 is weakened with increasing reaction temperature, which leads to the decrease of PLQY at 140 °C. However, non-radiative recombination is suppressed due to the microstructure improvement with further increasing the reaction temperature, and PLQY as high as 97% is achieved at 180 °C. Stability testing shows that fast degradation of α-CsPbI 3 NCs occur in low reaction temperature region, and α-CsPbI 3 NCs with high PLQY can be stored in air for 90 days when the reaction temperature is 180 °C.
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JOURNAL OF MOLECULAR LIQUIDS
·
2019
·
IF 4.561
Mingzhu Yang,Binglei Song,Delun Du,Xiaomei Pei,Zhenggang Cui
The aqueous solubility of surfactants is an important physicochemical property for their applications, and is expected to be improved by altering the molecular structures. Herein, a series of carboxylate surfactants with α-substituted phenoxy group, namely, sodium α-phenoxy alkyl carboxylates (C n -ph-Na, n = 12, 14, 16, 18, 20), were synthesized. Their solution and emulsion behaviors were investigated by surface tension, fluorescence probe method, confocal laser scanning microscopy (CLSM) and X-ray diffraction (XRD). Compared with conventional sodium carboxylate surfactants (C n Na), C n -ph-Na surfactants show extremely high water solubility of 1250, 1100, 800, 670 and 100 mmol·L − 1 for n = 12, 14, 16, 18 and 20, respectively, at 25 °C. The reason for this difference is the presence of the phenoxy group, which leads to the weak cohesive forces between the alkyl tails in the solid state. The high solubility of C n -ph-Na makes it possible to investigate Pickering emulsions stabilized with alumina (Al 2 O 3 ) nanoparticles hydrophobized by C n -ph-Na in situ. Both C 12 -ph-Na and C 14 -ph-Na can induce double phase inversion of the emulsions with increasing surfactant concentrations. The present work demonstrates the feasibility of adding hydrophobic groups to promote the water solubility of surfactants, providing a new approach for the molecular design and extending application of surfactants.
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 23
·9793-9801
·
IF 3.288
Yonghang Xu,Fangya Zhou,Min Chen,Huawen Hu,Limiao Lin,Jingshu Wu,Min Zhang
A novel, efficient and durable ZrP@PDA/Ag nanocatalyst was prepared via the facile reduction and deposition of silver nanoparticles (AgNPs) on two dimensional (2D) α-zirconium phosphate (ZrP) nanosheets using bio-inspired dopamine chemistry. The formation, adhesion and dispersion of AgNPs were confirmed by the full morphological and structural characterizations including SEM, TEM, FTIR, TGA, WXRD, and XPS. This ZrP@PDA/Ag nanocatalyst was evaluated by the reduction of 4-nitrophenol into 4-aminophenol, utilizing UV-vis absorption spectroscopy to monitor the reaction solution with a trace silver content of 0.125 μg mL−1. ZrP@PDA/Ag exhibits a superior catalytic activity compared with other noble metal nanocatalysts due to its high turnover frequency of 32.36 min−1 at room temperature without stirring, which is as high as almost 10 times that of the reported nanocatalysts using 2D graphene and silica supports. Furthermore, due to the excellent catalytic recyclability of ZrP@PDA/Ag it has very promising prospects in the treatment of organic pollutants in water.
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SYNTHESIS-STUTTGART
·
2022
·Vol. 54
·期 17
·3719-3728
·
IF 2.969
Xiaokang Kang,Shuyan Lai,Xiayu Liang,Qingle Zeng
1,1-Difunctionalization of α‑carbonyl sulfur ylides and thiosulfonates under simple conditions is disclosed. In this protocol, two new C–S bonds are constructed in a one-step reaction. A series of aliphatic and aromatic β-keto thiosulfones were obtained in moderate to good yields. This reaction probably proceeds through sulfur ylide-involved nucleophilic substitution of an ion pair within a solvent cage.
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EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
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2018
·
IF 4.816
Ying-Ying Zhong,Hui-Sheng Chen,Pan-Pan Wu,Bing-Jie Zhang,Yang Yang,Qiu-Yan Zhu,Chun-Guo Zhang,Su-Qing Zhao
Considerable interest has been attracted in oleanolic acid and its analogues because of their hypoglycemic activity. In this study, a series of novel oleanolic acid analogues against α-glucosidase were synthesized and their biological activities were evaluated in vitro and in vivo. In vitro α-glucosidase inhibition activity results indicated that most of the designed analogues exhibited prominent inhibition activities, especially compounds 10 , 15 , 16 and 26 which with the IC 50 values of 0.33 ± 0.01, 0.98 ± 0.06, 0.69 ± 0.01 and 0.72 ± 0.21 μM, respectively. Enzyme kinetic studies on the most potent compounds reveled that derivatives 10 , 15 , 16 and 26 were noncompetitive inhibitors. Moreover, the docking studies were carried out to prove that the four compounds could interact with the hydrophobic region of the active pocket and form hydrogen bonds to enhance the binding affinity of them with the α-glucosidase. Cytotoxicity evaluation assay demonstrated a high level of safety profile of the active compounds ( 10 , 15 , 16 and 26 ) against normal 3T3 cell line. Furthermore, the in vivo actual pharmacological potential studies on derivatives 10 , 15 , 16 and 26 showed that the hypoglycemic effects of them were comparable to that of positive control, acarbose .
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PROCESS BIOCHEMISTRY
·
2023
·
IF 4.4
Haiping Xiang,Weiyi Wen,Ping Xu,Huiyun Qiu,Chu Chu,Qingsong Shao,Shengqiang Tong
α -Glucosidase inhibitors can effectively control postprandial hyperglycemia and play a crucial role in treating type II diabetes. Geranylated compounds have been demonstrated to have strong α -glucosidase inhibitory activity, while their interaction mechanism was still unclear. In this study, we investigated the inhibition mechanisms of three structurally different geranylated compounds with significant α -glucosidase inhibition (puerarol, 8-geranyl-7, 3′-dihydroxy-4′-methoxyisoflavone, and xanthoangelol) separated from Pueraria lobata . The IC 50 values of these compounds were 6.14 ± 0.20, 2.35 ± 0.02, and 1.98 ± 0.07 μ M, respectively. It was found that puerarol acted as a non-competitive inhibitor, while 8-geranyl-7, 3′-dihydroxy-4′-methoxyisoflavone and xanthoangelol acted as un-competitive inhibitors. Fluorescence and circular dichroism data indicated that all three geranylated compounds statically quenched the fluorescence of α -glucosidase, and bound to α -glucosidase through a single binding site, inducing rearrangement of α -glucosidase and leading to conformational changes . Thermodynamic analysis and molecular docking revealed that puerarol interacted with α -glucosidase through hydrogen bonds and van der Waals forces, while the other two compounds primarily interacted through hydrophobic forces. This study elucidated the binding mechanism between three different structural geranylated compounds and α -glucosidase for the first time, which could contribute to the development of functional additives for the prevention and treatment of type II diabetes.
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BIOCHEMISTRY
·
2023
·
IF 2.9
Panpan Qi,Quankuo He,Junjie Zhang,Yuanyuan Lian,Ting Xie,Jianying Dong,Dongting Zhangsun,Yong Wu,Sulan Luo
α-Conotoxin GI is a competitive blocker of muscle-type acetylcholine receptors and holds the potential for being developed as a molecular probe or a lead compound for drug discovery. In this study, four fatty acid-modified α-conotoxin GI analogues of different lengths were synthesized by using a fatty acid modification strategy. Then, we performed a series of in vitro stability assays, albumin binding assays, and pharmacological activity assays to evaluate these modified mutants. The experimental results showed that the presence of fatty acids significantly enhanced the in vitro stability and albumin binding ability of α-conotoxin GI and that this effect was proportional to the length of the fatty acids used. Pharmacological activity tests showed that the modified mutants maintained a good acetylcholine receptor antagonistic activity. The present study shows that fatty acid modification can be an effective strategy to significantly improve conotoxin stability and albumin binding efficiency while maintaining the original targeting ion channel activity.
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Journal of Physical Chemistry C
·
2023
·
IF 3.7
Huiling Zhu,Cuixia Hao,Xin Li,Yao Qi,Xuesong Zhu,Yucheng Miao,Rui Liu,Jianxu Ding
Black phase CsPbI3 quantum dots (QDs) have garnered significant research interest due to their remarkable properties in optoelectronic applications. However, their inherent instability and low phase stability often lead to an undesired transformation into an orthorhombic yellow phase. In this study, we propose an innovative approach to synthesize Ag+ doped CsPbI3 QDs in a nonvacuum environment. The theoretical calculations and experimental results demonstrate that Ag+ doping substantially increases the formation energy and Goldschmidt tolerance factor, resulting in an enhanced thermodynamic stability and photoluminescence quantum yield (PLQY). The resulting Ag+ doped CsPbI3 QDs exhibit an impressive PLQY of up to 97% and maintain their black phase for over 60 days. This novel nonvacuum synthesis approach holds great potential for producing high-quality all-inorganic perovskite CsPbX3 QDs. To demonstrate the practical applications, we fabricate a white light-emitting diode (WLED) using the Ag+ doped CsPbI3 QDs, achieving Commission Internationale de I’Eclairage (CIE) color coordinates of (0.36, 0.26). These findings highlight the broad prospects of CsPbI3 QDs in lighting and display technologies.
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