BIOORGANIC CHEMISTRY
·
2022
·
IF 5.307
Hongjun Zhang,Zeguang Cheng,Litian Wei,Xinjun Yu,Zhao Wang,Yinjun Zhang
A gene encoding an esterase from Bacillus aryabhattai (BaCE) was identified, synthesized and efficiently expressed in the Escherichia coli system. A semi-rational protein engineering was applied to further improve the enzyme’s enantioselectivity. Under the guidance of the molecular docking result, a single mutant BaCE-L86Q and a double mutant BaCE-L86Q/G284E were obtained, with its E max value 6.4 times and 13.9 times of the wild-type BaCE, respectively. The recombinant BaCEs were purified and characterized. The overwhelming E value demonstrated that BaCE-L86Q/G284E was a promising biocatalyst for the biological resolution to prepare ( S )-indoline-2-carboxylic acid.
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MACROMOLECULAR RAPID COMMUNICATIONS
·
2020
·Vol. 41
·期 17
·2000307
·
IF 4.886
Kesong Tian,Junyan Wang,Wanchun Guo,Ruifei Li,Ling Cao,Zhaopeng Xu,Haiyan Wang
Yolk–shell magnetic nanoparticles@nitrogen-enriched Carbon nanostructures with a magnetic core and a hollow nitrogen-enriched carbon shell exhibit considerable promise in various applications, such as drug delivery, heterogenous catalysts, removal of metal ions and organic pollutants, and screening of biomolecules, due to their strong magnetic response, unique cavities, and the selective absorption ability of nitrogen-enriched groups. However, their complicated synthesis always involves possible surface modification, layer-by-layer deposition of a sacrificial middle layer and an outer nitrogen-enriched layer on magnetic nanoparticles, subsequent carbonization, and final removal of the sacrificial middle layer. Herein, yolk–shell Fe 3 O 4 @nitrogen-enriched carbon nanostructures are constructed based on NH 4 + ion-induced one-step deposition of SiO 2 and Resorcinol-3-aminophenol-formaldehyde cocondensed resin (R-APF) dual layers onto poly acrylic acid-modified Fe 3 O 4 nanoclusters without any extra surface modification. The N-Carbon shell thickness of the yolk–shell Fe 3 O 4 @Void@N-Carbon nanostructure can be finely tailored though tailoring the feeding amount of aminophenol and resorcinol to tune the thickness of the outer R-APF resin shell onto Fe 3 O 4 @SiO 2 intermediate particles. This NH 4 + ion-induced one-pot deposition of double layers can effectively promote synthesis efficiency of this kind of yolk–shell nanostructure.
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TETRAHEDRON-ASYMMETRY
·
2014
·
IF 2.165
Rui-Jie Chen,Gao-Wei Zheng,Yan Ni,Bu-Bing Zeng,Jian-He Xu
A new NADH-dependent carbonyl reductase Rh CR capable of efficiently reducing the ε-ketoester ethyl 8-chloro-6-oxooctanoate (ECOO) to give ethyl ( S )-8-chloro-6-hydroxyoctanoate [( S )-ECHO], an important chiral precursor for the synthesis of ( R )-α-lipoic acid, was identified from Rhodococcus sp. ECU1014. Using recombinant Escherichia coli cells expressing Rh CR and glucose dehydrogenase used for the regeneration of cofactor, 440 g L −1 (2 M) of ECOO were stoichiometrically converted to ( S )-ECHO in a space–time yield of 1580 g L −1 d −1 without the external addition of any expensive cofactor.
研究领域:
生物催化
·
酶工程
·
合成化学
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生物技术
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Tingting Yan,Binglei Song,Delun Du,Zhenggang Cui,Xiaomei Pei
Innovations in surfactant structures are a feasible way to prepare unique molecular aggregates with interesting properties. Herein, taking dehydroabietic acid as the starting material, a new amine oxide surfactant, abbreviated as R-8-AO, was synthesized. Cryogenic transmission electron microscopy (cryo-TEM) images and circular dichroism (CD) spectra reveal that at suitable concentrations, R-8-AO molecules form rarely discovered right-handed chiral wormlike micelles , which have a cross-sectional diameter of 5–6 nm. The overlap concentration of R-8-AO is approximately 8 mM, above which the wormlike micelles began to entangle in solutions. Due to the strong van der Waals forces between R-8-AO molecules, the scaling law gives an exponent of 7.88, which is higher than the theory predicted value. Gold nanoparticles were synthesized in-situ by irradiating mixed solutions of HAuCl 4 and wormlike micelles formed by R-8-AO with UV light . These ultrasmall spherical gold nanoparticles, which are located at the surface of wormlike micelles, have a uniform particle size of 3 ± 1 nm, as observed by TEM. In addition, the gold nanoparticles form a worm-like morphology induced by the wormlike micelles, showing soft-aggregate-directed nanoparticle assembly. This work is first to reveal the effectiveness of preparing ultrasmall gold nanoparticles with new morphological wormlike micelles as soft templates. The resulting organic-inorganic hybrid aggregates are also expected to find applications in catalysis and electronic fields.
研究领域:
表面活性剂化学
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纳米材料
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材料科学
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胶体科学
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纳米技术
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CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ce Li,Xu Zhang,V.C. Onah,Weiling Yang,Zhuang Leng,Xiliang Jiang,Fangming Zhang,Shasha Li,Yong Zhang,Yu Han,Huisheng Liu,Chun Li,Dingfu Zhou,Fanming Zeng
In analyzing the effect of alkali metal and alkaline earth metal oxide on the properties of tellurite glass , a series of tellurite glass samples doped with alkali metals and alkaline earth metals were prepared based on the TeO 2 -WO 3 -GdF 3 glass system by melt quenching method. Through tests and comprehensive analysis, the results show that after the F − ions successfully enter the glass network, the substitution of TeO 2 by alkali and alkaline earth metals could reduce the molar volume , which means the glass becomes more compacted. The influence on the glass network is mainly shown in [TeO 3 ] and [TeO 4 ] units. Alkali metals and alkaline earth metals could increase the asymmetry of the TWG: Eu 3+ glass network, shorten the critical distance, and increase luminescence intensity by 8.6 times and improve color purity to 94%. In addition, alkali metals could prolong the fluorescence lifetime , while alkaline earth metals could shorten it. Te 4+
研究领域:
材料科学
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光学材料
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玻璃物理
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发光光谱学
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无机化学
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Analytical Methods
·
2023
·
IF 3.1
Yan Wu,Chengwei Zuo,Yujie Mou,Hao Wang,Yongrui Hou,Xiaodong Su,Zhenfu Jia,Huidong Qiu
In this study, a new type of red light-emitting carbon dots (R-CDs) that can selectively recognize Cr(VI) was prepared by using the strategy of 2,4-diaminophenol to enhance the fluorescence of O-phenylenediamine based carbon dots. The results showed that 2,4-diaminophenol increased the quantum yield (QY) of carbon quantum dots (CDs), and the QY of CDs increased from the original 8.7% to 20.1%(R-CDs). R-CDs show sensitivity to acidic conditions and maintain good linearity between pH = 1.00-4.00, making them useful for pH probes. Furthermore, the prepared R-CDs possess good solubility in water. They are responsive to changes in Cr(VI) concentrations in aqueous environments. R-CDs' quenching was linearly correlated with the Cr(VI) concentration within a range of 0-20 μM, with a lower detection limit of 66 nM. The detection mechanism is attributed to the formation of hydrogen bonds between Cr(VI) and R-CDs, resulting in the fluorescence quenching of R-CDs. R-CDs could be considered effective multifunctional fluorescent probes for pH and Cr(VI) in aqueous environments. This study will provide new R-CD design strategies that selectively identify specific target substances.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2020
·Vol. 22
·期 30
·17299-17305
·
IF 3.43
Chenyang Zhou,Ya Chu,Linlin Ma,Yingqian Zhong,Chao Wang,Yalan Liu,Haoyue Zhang,Beibei Wang,Xia Feng,Xi Yu,Xiaotao Zhang,Yan Sun,Xiaozeng Li,Guangjiu Zhao
In this work, we introduced halogen-substituted chiral molecules as A-site cations to synthesize a series of novel organic–inorganic hybrid two-dimensional (2D) chiral perovskite materials (R-X-p-mBZA)2PbBr4 (X = H, F, Cl, Br; p: para-position; mBZA = α-methylbenzylamine) for the first time. This halogen-substituted cation strategy collectively solved problems of narrow emission, weak chirality and low photoluminescence quantum yield (PLQY) for the emerged chiral perovskites. Photoluminescence (PL) spectra are significantly broadened due to the additional emission from self-trapped excitons (STEs) besides free excitons (FEs) states modulated by introducing significant disorder to the Pb–Br–Pb angle. The chirality of A-site chiral molecules is transferred and amplified to entire perovskite materials by fixing the chiral molecules at A-site via the interaction of halogen atoms. Furthermore, their PLQYs are improved with the reduction of energy gap and inhibition of the non-radiative transition from STEs to ground state. The halogen-substituted A-site cation strategy can be performed to develop organic–inorganic hybrid chiral perovskites with various optoelectronic applications.
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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2023
·
IF 3.4
Yao Wang,Yuhan Liu,Yutong Sha,Jia Li,Luyao Han,Huili Chen,Shengdi Su,Ning Li,Xijing Chen,Di Zhao
A chiral UPLC-MS/MS method was developed and validated to determine oxiracetam enantiomers in human plasma, urine, and feces. The R-Oxiracetam and S-Oxiracetam were quantified using a CHIRALPAK ®AD3 column at 25 ℃, and the resolution was greater than 3.2. The S-Oxiracetam is the eutome r that isresponsible for the treatment of various brain damage. Isocratic elution was conducted at a flow rate of 0.9 mL/min for 6 min using the mixture of methanol and acetonitrile (methanol:acetonitrile, 15:85) containing 0.3‰ formic acid . The methods showed linearity at the range of 0.5–100 µg/mL for each oxiracetam enantiomer. A comprehensive validation process was carried out, covering aspects including linearity, selectivity, carryover, accuracy, precision, interferences, matrix effect, recovery, dilution integrity and stability in matrix and solution. The validated methods were successfully applied to quantifying R-Oxiracetam and S-Oxiracetam in human plasma, urine, and feces of 12 healthy subjects treated with either a single dose of 2 g S-Oxiracetam injection or 4 g Oxiracetam injection in a phase-I clinical trial . There was no significant difference for plasma pharmacokinetic parameters of S-Oxiracetam between the two regimens ( P＞0.05 ). The S-Oxiracetam and Oxiracetam were primarily eliminated through urine in their original form, with cumulative excretion rates of 92.16% and 85.92%, respectively, within 24 h after administration. Enantiomers interconversion was not observed in the plasma, urine, or feces. The results of this study suggest that replacing 4 g Oxiracetam injection with 2 g S-Oxiracetam injection could offer clinical benefits by lowering the dosage and mitigating potential risks, based on the pharmacokinetic characteristics.
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RSC Advances
·
2016
·Vol. 6
·期 86
·82707-82715
·
IF 3.289
Wei Li,Rui-tang Guo,Shu-xian Wang,Wei-guo Pan,Qi-lin Chen,Ming-yuan Li,Peng Sun,Shu-ming Liu
A series of Mn/CeSiOx catalysts were prepared by the wet impregnation method and used for selective catalytic reduction of NO with NH3. As can be seen from the experimental results, the Mn/CeSiOx catalyst with a Ce/Si molar ratio of 2/1 showed excellent low-temperature SCR activity, high N2 selectivity and excellent SO2 and H2O tolerance. The relationship between the CeSiOx support and the SCR performance of Mn/CeSiOx (2 : 1) catalyst was investigated based on the characterization results of N2 adsorption, XRD, XPS, H2-TPR, NH3-TPD and in situ DRIFT. The strong interaction between Ce and Si resulted in the good dispersion of Mn species on the support; correspondingly, the redox ability and NH3 adsorption capacity were greatly enhanced. The results of in situ DRIFT study revealed that the NH3-SCR reactions over Mn/CeO2 and Mn/CeSiOx (2 : 1) mainly obeyed both the E–R mechanism and the L–H mechanism. Furthermore, the formation of more Mn4+ and chemisorbed oxygen greatly facilitates the oxidation of NO to NO2, as a result, promoting the low-temperature SCR performance of Mn/CeSiOx (2 : 1).
研究领域:
催化
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环境科学
·
化工
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JOURNAL OF NANOBIOTECHNOLOGY
·
2021
·Vol. 19
·期 1
·1-15
·
IF 10.435
Guo Lin,Huang Zhixuan,Huang Lijuan,Liang Jia,Wang Peng,Zhao Liang,Shi Yijie
Background The incidence of ischemic stroke in the context of vascular disease is high, and the expression of growth-associated protein-43 (GAP43) increases when neurons are damaged or stimulated, especially in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). Experimental design We bioengineered neuron-targeting exosomes (Exo) conjugated to a monoclonal antibody against GAP43 (mAb GAP43) to promote the targeted delivery of quercetin (Que) to ischemic neurons with high GAP43 expression and investigated the ability of Exo to treat cerebral ischemia by scavenging reactive oxygen species (ROS). Results Our results suggested that Que loaded mAb GAP43 conjugated exosomes (Que/mAb GAP43-Exo) can specifically target damaged neurons through the interaction between Exo-delivered mAb GAP43 and GAP43 expressed in damaged neurons and improve survival of neurons by inhibiting ROS production through the activation of the Nrf2/HO-1 pathway. The brain infarct volume is smaller, and neurological recovery is more markedly improved following Que/mAb GAP43-Exo treatment than following free Que or Que-carrying exosome (Que-Exo) treatment in a rat induced by MCAO/R. Conclusions Que/mAb GAP43-Exo may serve a promising dual targeting and therapeutic drug delivery system for alleviating cerebral ischemia/reperfusion injury.
研究领域:
神经科学
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药理学
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分子生物学
·
生物医学工程
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高影响因子
Cell Reports
·
2024
·
IF 7.5
Sijia Ren,Feng Bai,Viviane Schnell,Clara Stanko,Muriel Ritsch,Tino Schenk,Emanuel Barth,Manja Marz,Bin Wang,Xin-Hai Pei,Holger Bierhoff
Extensive remodeling of the female mammary epithelium during development and pregnancy has been linked to cancer susceptibility. The faithful response of mammary epithelial cells (MECs) to hormone signaling is key to avoiding breast cancer development. Here, we show that lactogenic differentiation of murine MECs requires silencing of genes encoding ribosomal RNA (rRNA) by the antisense transcript PAPAS. Accordingly, knockdown of PAPAS derepresses rRNA genes, attenuates the response to lactogenic hormones, and induces malignant transformation. Restoring PAPAS levels in breast cancer cells reduces tumorigenicity and lung invasion and activates many interferon-regulated genes previously linked to metastasis suppression. Mechanistically, PAPAS transcription depends on R-loop formation at the 3' end of rRNA genes, which is repressed by RNase H1 and replication protein A (RPA) overexpression in breast cancer cells. Depletion of PAPAS and upregulation of RNase H1 and RPA in human breast cancer underpin the clinical relevance of our findings.
研究领域:
癌症生物学
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分子生物学
·
细胞生物学
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INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Shiju Yang,Xueshuang Yan,Fuzhi He,Zhuliang Chen,Kaizhu Chang,Wan Yang,Futing Xia,Jianjun Chen,Qiulin Zhang
Achieving remarkable activity in selective catalytic reduction of NO by NH3 (NH3-SCR) over CeO2-based catalysts was crucial for their industrial application but still faces a tough challenge, mainly owing to the insufficient acidity and overoxidation ability. Herein, the surface acidity and reducibility of CeO2 catalysts were finely tuned over Mn–W/CeO2 to efficiently eliminate NO and reveal the mechanistic origin of superior catalytic properties. Systematic surface and structure analyses revealed that Mn3O4 interacted with WO3 species in the possible form of Mn–O–W, which could enhance the dispersion of WO3 over the CeO2 surface. The resulting well-dispersed WO3 increased the concentration of both Brønsted acid sites and strong acid sites, effectively suppressing the generation of inactive nitrates and thus providing abundant catalytically active sites for the adsorption and activation of NH3. Importantly, the electron withdrawal from Mn by W atoms associated with the shortened Mn–O bond distance resulted in the appropriate reducibility over Mn–W/CeO2. Accordingly, the undesirable overoxidation of NH3 was weakened, thereby greatly increasing the high-temperature (250–400 °C) NH3-SCR activity. DFT calculations and detailed in situ DRIFTS analysis demonstrated that both “E–R” and “L–H” mechanisms contributed mainly to this superior performance.
研究领域:
催化
·
环境化学
·
表面科学
·
材料科学
·
化学反应工程
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