CATALYSIS LETTERS
·
2025
·Vol. 155
·期 5
·1-14
·
IF 2.4
Wang Xiangke,Meng Xuan,Shi Li,Liu Naiwang,Wang Jiyu
In the tert-butyl removal reaction, solid acid catalysts have emerged as a preferred alternative to liquid acid catalysts due to their environmentally friendly advantages. Various zeolites, such as ZSM-5, MCM-41, USY, and H beta, as well as mesoporous materials, such as γ-Al 2 O 3 and active clay were employed for the first time to prepare m-cresol through the tert-butyl removal reaction of 4,6-di-tert-butyl-m-cresol (4,6-DBMC). γ-Al 2 O 3 and active clay catalysts were found to have excellent catalytic performance in this reaction. The thermodynamic properties of the tert-butyl removal reaction of 4,6-DBMC were studied. Under different temperature and solvent conditions, the product distribution was investigated. A proposed reaction pathway and mechanism were proposed. And through cyclic experiments, the stability of γ-Al 2 O 3 and active clay catalysts was investigated separately. After six cycles, the m-cresol yield for active clay catalyst was still maintained at about 90%. The causes of deactivation of the two catalysts were analyzed. After regeneration, both catalysts exhibited good regeneration performance. This study offers a basis for the selection of solid acid catalysts for the tert-butyl groups removal of 4,6-DBMC. Graphical abstract
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2022
·Vol. 24
·期 11
·1-12
·
IF 2.533
Shen Xingwang,Xi Shuang,Xu Liang,Zhao Tao,Sun Rong,Li Junjie
A rising variety of power devices based on wide-bandgap (WBG) semiconductors are employed in products that can service at high temperatures consistently for extending the working life. Traditional tin–lead and lead-free solders are no longer suitable for power device packaging. Recently, nano-Ag pressureless sintering technology has attracted widespread attention for high-temperature application. When commercial Ag powders are applied, satisfactory sintering quality is often not obtained due to unstable product batches, unknown surface cladding, and poor sintering performance. In this work, Ag nanoparticles are surface modified with tert-dodecyl mercaptan (TDM) to prevent agglomeration at room temperature for improving pressureless sintering performance. We systematically introduced the modification process of Ag nanoparticles and Ag paste preparation and sintering process and compared the changes in the sintering performance of modified Ag nanoparticles with different TDM contents. With a minor amount of TDM, 1.5% of the total weight of Ag, the sintering performance of the Ag paste can be effectively improved and the porosity reduced. The highest average shear strength of the bonded joints based on modified Ag nanoparticles is up to 46.82 MPa with only 6.1% porosity by pressureless and low-temperature sinter at 250 °C for 10 min in ambient air, and the sintering morphology is better than the joints without nanoparticle modification. At the same time, increasing the sintering time does not have much effect on the bond strength, which indicated that 10 min already formed a high-quality joint. The analysis reveals that TDM molecules can be absorbed on the surface of Ag nanoparticles by headgroups to form a coating layer. The mechanism of TDM modification to enhance the sintering performance is also proposed, which provides theoretical support for the practical application of the pressureless Ag sintering technology. Graphical abstract
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
高影响因子
ELECTROPHORESIS
·
2017
·
IF 2.744
Meng Ruan,Qiqin Wang,Huihui Wu,Yuqiang Wang,Hai Han,Zhengjin Jiang
In this study, a novel functional monomer N -[1-( α -naphthyl)ethylaminocarbonyl]-D- tert -leucine-[2-(methacryloyloxy)ethyl] amide (NA-D- tert -Leu-MA) was synthesized, and then employed to prepare polymeric monoliths (240 mm × 100 μm id) functionalized with tert -leucine derivative through a single step thermo-initiated co-polymerization approach or a multi-step post-modification approach. The multi-step approach involves the post-modification of a thiol-containing monolith with NA-D- tert -Leu-MA via “thiol-ene”click reaction. The physicochemical properties of the resulting monoliths were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry and micro-liquid chromatography. Good column stability, permeability, efficiency and reproducibility were obtained for the optimized monoliths. The poly (NA-D- tert -Leu-MA- co -ethylene dimethacrylate) monolith prepared through the single step co-polymerization approach exhibited satisfactory achiral separation performance for various analytes, including phenols, aniline derivatives and intact proteins, while its enantioseparation ability is rather poor. In contrast to that, the monolith prepared through the multi-step post-modification approach showed much higher enantioselectivity for 7-nitro-2,1,3-benzoxadiazole (NBD)-derivatized amino acids. Three NBD-derivatized amino acids (theanine, proline and norleucine) could be baseline enantioseparated.
研究领域:
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Weiyan Guan,Juan Cheng,David Julian McClements,Zongcai Tu,Jing Chen,Da Ma
2,4-di-tert-butylphenol (2,4-DTBP) is an additive used in food packaging. The inhibitory effects of 2,4-DTBP on pancreatic lipase (PL) were investigated in this study. Kinetic analysis indicated that 2,4-DTBP competitively and reversibly inhibited PL activity. At 4.85 mM, PL activity decreased by 35.5 ± 1.6 %. 2,4-DTBP quenched the fluorescence of PL by hydrogen bonding and van der Waals forces. Circular dichroism spectroscopy showed that 2,4-DTBP induced changes in the secondary structure of PL. Molecular docking revealed that 2,4-DTBP interacted with Phe77, Leu153, and Ser152 residues of PL, which account for suppressing lipid hydrolysis. An in vitro digestion study showed that 2,4-DTBP inhibited the digestion of lipid in oil-in-water emulsions. This study improved our understanding of the effects of 2,4-DTBP on digestive enzyme. It also underscored the need for better monitoring and control of the leaching of this additive from packaging materials into foods.
研究领域:
食品科学
·
生物化学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PHYTOTHERAPY RESEARCH
·
2021
·Vol. 35
·期 10
·5767-5780
·
IF 5.882
Lin Zhu,Zhenchao Liu,Yuqian Ren,Xiaolin Wu,Yingjuan Liu,Tingting Wang,Yizhao Li,Yusheng Cong,Yunliang Guo
Studies have found that salidroside, isolated from Rhodiola rosea L , has various pharmacological activities, but there have been no studies on the effects of salidroside on brain hippocampal senescence. The purpose of this study was to investigate the mechanistic role of salidroside in hippocampal neuron senescence and injury. In this study, long-term cultured primary rat hippocampal neurons and naturally aged C57 mice were treated with salidroside. The results showed that salidroside increased the viability and MAP2 expression, reduced β-galactosidase (β-gal) levels of rat primary hippocampal neurons. Salidroside also improved cognition dysfunction in ageing mice and alleviated neuronal degeneration in the ageing mice CA1 region. Moreover, salidroside decreased the levels of oxidative stress and p21, p16 protein expressions of hippocampal neurons and ageing mice. Salidroside promoted telomerase reverse transcriptase (TERT) protein expression via the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway. In conclusion, our findings suggest that salidroside has the potential to be used as a therapeutic strategy for anti-ageing and ageing-related disease treatment.
研究领域:
神经科学
·
药理学
·
衰老研究
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2019
·Vol. 43
·期 1
·21-31
·
IF 2.371
Zhang Xiao-Jian,Wang Wen-Zhong,Zhou Rong,Liu Zhi-Qiang,Zheng Yu-Guo
Abstract tert -Butyl (3 R ,5 S ) - 6-chloro-3,5-dihydroxyhexanoate [(3 R ,5 S )-CDHH] is the key chiral intermediate to synthesize the side chain of the lipid-lowering drug rosuvastatin. Carbonyl reductases showed excellent activity for the biosynthesis of (3 R ,5 S )-CDHH. The requirement of cofactor NADH/NADPH leads to high cost for the industrial application of carbonyl reductases. In this study, a self-sufficient biocatalyst based on carbonyl reductase and NADP + co-immobilization strategy was developed on an amino resin carrier LX-1000HAA (SCR-NADP + @LX-1000HAA). The self-sufficient biocatalyst achieved in situ cofactor regeneration and showed the activity recovery of 77.93% and the specific activity of 70.45 U/g. Asymmetric synthesis of (3 R ,5 S )-CDHH using SCR-NADP + @LX-1000HAA showed high enantioselectivity (> 99% e.e.) and yield (98.54%). Batch reactions were performed for ten cycles without extra addition of NADP + , and the total yield of (3 R, 5 S )-CDHH achieved at 10.56 g/g biocatalyst. The present work demonstrated the potential of the self-sufficient biocatalyst for the asymmetric biosynthesis of rosuvastatin intermediate. Graphic abstract
研究领域:
生物化学
·
酶工程
·
药物合成
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Science
·
2024
·
IF 14.3
Lijiao He,Xiao Zhang,Shengwei Zhang,Yi Wang,Weichao Hu,Jie Li,Yunyi Liu,Yu Liao,Xue Peng,Jianjun Li,Haiyan Zhao,Liting Wang,Yang-Fan Lv,Chang-Jiang Hu,Shi-Ming Yang
Persistent H. pylori infection triggers the repair program of the mucosa, such as spasmolytic polypeptide-expressing metaplasia (SPEM). However, the mechanism underlying the initiation of SPEM in gastric tissues by H. pylori remains unclear. Here, an increase in telomerase reverse transcriptase (TERT) protein expression is observed in chief cells upon infection with cagA -positive H. pylori . Tert knockout significantly ameliorated H. pylori -induced SPEM and single-cell RNA sequencing demonstrated that the Wnt/β-Catenin pathway is suppressed in gastric cells with Tert knockout. Mechanism study revealed that CagA elevated TERT abundance by disrupting the interaction between TERT and its novel E3 ligase, SYVN1. Interestingly, Nitazoxanide effectively relieved SPEM via inhibition of the Wnt/β-Catenin signaling in vivo. This results clarified the mechanism underlying which CagA activated the TERT/Wnt/β-Catenin pathway, thus promoting the dedifferentiation of chief cells and the occurrence of SPEM in gastric mucosa. This highlights a molecular basis for targeting CagA-activated Wnt signaling in chief cells for the treatment of gastric precancerous lesions.
研究领域:
胃肠病学
·
分子生物学
·
肿瘤学
·
病理学
✓ 已验证
DOI
PubMed
高影响因子
MONATSHEFTE FUR CHEMIE
·
2015
·Vol. 147
·期 6
·1101-1105
·
IF 1.222
Tu Xingzhao,Xiong Jing,Li Zhijie,Zhou Lihong,Emmanouil Christina,Zeng Qingle
Abstract The valuable 2-( tert -butyldisulfanyl)heterocycles were effectively synthesized from 2-mercaptoheterocycles and tert -butanesulfinamide via unusual condensation. The reaction between 2-mercapto sulfur-containing heterocycles and tert -butanesulfinamide was performed under ligand-free CuI-catalyzed conditions. The synthetic processes described herein are simple, cost-efficient, and practical. Furthermore, a plausible mechanism is proposed for this transformation. Graphical abstract
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL RESEARCH
·
2018
·
IF 0.668
Yixian Han,Hua Song,Yuanyuan Wang,Xinglong Sun,Zhigang Sun
A series of transition metal oxide-modified HBEA (Mx0y/HBEA) zeolite catalysts were prepared by the wetness impregnation method, and investigated for the alkylation of toluene with tert-butanol to synthesise 4-tert-butyltoluene (4-TBT). Their physico-chemical properties were characterised by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller and NH3 temperature-programmed desorption methods. Mx0y/HBEA zeolite showed higher para-selectivity than parent HBEA due to its improved structural and acidic properties. Though the toluene conversion of Mx0y/HBEA catalyst decreased, the 4-TBT selectivity increased significantly at 190 °C after 4 h. The narrowed pores after loading the Mx0y prompted an increase in selectivity for 4-TBT by increasing the shape selectivity. In addition, the decrease in strong acid sites increased selectivity for 4-TBT by suppressing further isomerisation of the 4-TBT formed on acid sites. Among all the modified HBEA zeolites, Fe203/HBEA exhibited the best catalytic activity and para-selectivity. The factors affecting the reaction over Fe203/HBEA have also been investigated extensively.
✓ 已验证
DOI
高影响因子
Food & Function
·
2021
·Vol. 12
·期 7
·2914-2924
·
IF 5.396
Li Tao,Wei Zhang,Yaxin Zhang,Mei Zhang,Yueying Zhang,Xing Niu,Qing Zhao,Zhenxing Liu,Yuyin Li,Aipo Diao
Telomere shortening is one of the main causes of cellular senescence. Caffeine is a natural stimulant most commonly found in coffee and tea. In this study, caffeine was found to promote the expression of telomerase reverse transcriptase (TERT) at both mRNA and protein levels, and consequently extended the telomere length and prevented cellular senescence. Knockdown of TERT eliminated the effect of caffeine on telomere elongation. Moreover, animal studies indicated that caffeine promoted the expression of TERT and extended the telomere length in the thymus and spleen of mice treated with caffeine for a long period of eight months. In addition, caffeine restored the decline of organ index and improved the histological structural change of the thymus, spleen and liver of mice due to aging. These results suggest that caffeine promotes the expression of TERT to delay cellular senescence and aging, which help to understand the mechanism for the beneficial effects of caffeine containing foods on health.
研究领域:
分子生物学
·
老年学
·
营养学
·
细胞生物学
✓ 已验证
DOI
PubMed
高影响因子
THERMOCHIMICA ACTA
·
2020
·
IF 2.762
Peiran Li,Xue Wang,Yaling Chen,Tianxiang Yin,Weiguo Shen
Different microscopic and thermodynamic properties like the resonance light scattering intensity, microenvironment polarity, the density and heat capacity of {water + TBA} binary solution and the density of {water + TBA + IBA} ternary solution were precisely measured. Formation and structure transitions of alcohol-water aggregate in TBA aqueous solution and {water + TBA + IBA} ternary solutions at different compositions were investigated by analysis of both microscopic and thermodynamic properties. It is indicated from the results that the fine structure transitions in hydrotrope solutions can be well reflected by the variance of thermodynamic properties, which provides an efficient way to give deeper insight into the structure changes in aqueous hydrotrope solutions.
研究领域:
物理化学
·
溶液热力学
·
分子结构分析
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Rui Wang,Na Li,Xing Hu,Junhui Pan,Guowen Zhang,Xinan Zeng,Deming Gong
The binding characteristics of food antioxidant tert -butylhydroquinone (TBHQ) and its oxidation product tert -butylquinone (TBQ) with calf thymus DNA (ctDNA) in vitro were investigated using multispectroscopy, chemometrics , viscosity measurements, gel electrophoresis assays and molecular docking . Analysis of fluorescence spectra found that TBHQ and TBQ bound with ctDNA to form 1:1 complexes with the binding constant in the order of 10 4 L mol −1 . The concentration profiles and the pure spectra for the components (TBHQ, TBQ, ctDNA and TBHQ– or TBQ–ctDNA complex) were obtained through analyzing the expanded ultraviolet-visible absorption data matrix by multivariate curve resolution–alternating least squares algorithm, which successfully monitored the binding process of TBHQ/TBQ with ctDNA. Fluorescence displacement, viscosity and molecular docking experiments showed that TBHQ bound to ctDNA through intercalation binding, while TBQ bound to the minor groove of ctDNA. The binding of TBHQ to ctDNA induced the conversion of DNA conformation from B-form to A-form, while TBQ caused a minor perturbation on the DNA conformation. Gel electrophoresis results indicated that the combination of TBHQ and Cu(II) could induce DNA damage. This study may contribute to understanding the binding mechanisms of TBHQ and TBQ with ctDNA and further evaluate the potential toxicological effects of TBHQ as a food additive .
研究领域:
生物化学
·
分子生物学
·
毒理学
·
食品科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）