Current Pharmaceutical Analysis
·
2020
·Vol. 16
·期 6
·763-773
·
IF 0.923
Yaro Peter,Nie Jing,Xu Mingcheng,Zeng Kui,Zeng Su
Background: Terpene lactones are major components of ginkgo biloba extract which are used in cardiovascular and degenerative diseases. To study the involvement of transporters in the transport/disposition of ginkgolides A, B, C, and bilobalide, a bioanalytical assay was developed by
LCMS/ MS system for the quantitation of intracellular levels of terpene lactones in cells expressing organic cation transporter 2 (OCT2). Methods: The assay involved an optimized simple sample handling with methyl tert-butyl ether for liquid-liquid extraction and reconstitution in modified
dissolution solution. Pretreatment of samples with 50 μM ascorbic acid and the addition of ascorbic acid and formic acid in dissolution solution significantly reduced matrix effect and stabilized the postpreparative samples. Separations were performed by Zobrax RRHD column (extend-C18 1.8μm,
3.0 x 100mm) and acetonitrile gradient elution. The analysis was carried out in the negative ion scan mode using multiple reaction monitoring. Results: The method was validated for linearity (concentration range of 20-5000nM), accuracy (±13.1%), precision (<11.0%), recovery
(94.31–105.9%), matrix effect (93.8-111.0%) and stability. Finally, the method was applied in the determination of intracellular concentrations of ginkgolides A, B, C, and bilobalide in Madin-Darby canine kidney (MDCK-mock) and MDCK-OCT2 cells in uptake study. Conclusion: The developed
method was successfully validated. Results suggest that OCT2 is involved in the renal disposition of ginkgolide A, B, and bilobalide. This method would foster the study of transport mediated activity via the interaction of ginkgolides and bilobalide with cellular systems.
研究领域:
药理学
·
分析化学
·
药物代谢
✓ 已验证
DOI
高影响因子
RSC Advances
·
2022
·Vol. 12
·期 37
·24288-24300
·
IF 4.036
Xi He,Shiyang Yu,Huimin Wang,Zilu Tian,Jiahui Zhang,Ying Zhao,Haihuan Gong,Zuosen Shi,Zhanchen Cui,Song Zhu
Bonding failure is one of the main causes of failure of dental restorations. The bonding strength, aging resistance, and polymerization shrinkage of cement can affect the stability of the bonding interface and lead to marginal microleakage. To reduce the bonding failure rate of restorations, a novel polyurethane (PU) cement was designed to improve the mechanical properties, hydrophobicity, degree of conversion (DC), polymerization shrinkage, bond strength and aging resistance of cement by introducing isophorone diisocyanate (IPDI) and hydroxyethyl methacrylate (HEMA) and adjusting the polyester : polyether ratio to increase the degree of cross-linking. Experimental results verified that the novel PU could increase the mechanical properties and thermal stability of the cement, reduce polymerization shrinkage during the curing reaction, improve the bonding performance and DC, endow the cement with hydrophobic properties, and improve its ability to resist aging in the salivary environment to maintain the long-term stability of interfacial bonding under the influence of comprehensive factors. The results of this study provide a new direction and insights to reduce microleakage and improve the success rate of restorations.
研究领域:
牙科学
·
材料科学
✓ 已验证
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Han Hu,Ruoyu Zhang,Jinggang Wang,Wu Bin Ying,Jin Zhu
A series of aromatic-aliphatic poly(propylene succinate-co-furandicarboxylate) (PPSF) copolyesters, with compositions varied over the whole range from that of poly(propylene succinate) (PPS) to poly(propylene furandicarboxylate) (PPF), were synthesized by transesterification and melt polycondensation. 1 H NMR study suggested the random segment distribution of PPSF. The copolymer showed slower crystallization rate than that of terephthalate based copolyesters, as indicated by DSC tests. PPSFs with low furandicarboxylate molar content ( m PF ) (from 10% to 50%) were soft and elastic due to their poor crystallization ability and low T g . In contrast, they owned relatively high elastic modulus, tensile strength and excellent barrier properties with high m PF (from 60% to 90%). Annealing treatment could speed up the crystallization of PF units and increase the elastic modulus and tensile strength of PPSFs. The chemical composition of the copolymer strongly influenced its permeability to CO 2 and O 2 , and PPSF owned better CO 2 , O 2 and H 2 O barrier properties than commercial PBAT and PLA. Furthermore, enzymatic degradation study suggested that copolymers with m PF up to 60 mol% could be degraded and PPSF became easier to degrade with the increasing content of succinate units ( m PS ).
研究领域:
材料科学
·
高分子化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
·
2013
·
IF 2.487
Pei Liang,Guojiao Liu,Fang Wang,Wanting Wang
A novel method, ultrasound-assisted surfactant-enhanced emulsification microextraction with solidification of floating organic droplet (UASEME-SFOD), has been developed for the extraction of four strobilurin fungicides (kresoxim-methyl, picoxystrobin, pyraclostrobin and trifloxystrobin) in fruit juices. In the UASEME-SFOD technique, Tween 80 was used as emulsifier, and 1-undecanol was used as extraction solvent without using any organic dispersive solvent. Several parameters that affect the extraction efficiency, such as the kind and volume of extraction solvent, the type and concentration of the surfactant, extraction time, extraction temperature and salt addition were investigated and optimized. Under the optimum extraction condition, the method yields a linear calibration curve in the concentration range from 5 to 10,000 ng mL −1 for the targeted analytes with the correlation coefficient ranging from 0.9991 to 0.9998. The enrichment factors were in the range between 95 and 135, and the limits of detection of the method were 2–4 ng mL −1 . The fruit juice samples were successfully analyzed using the proposed method, and the relative recoveries at fortified levels of 50 and 100 ng mL −1 were in the range of 82.6–97.5%.
研究领域:
分析化学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials
·
2017
·Vol. 10
·期 2
·149
·
IF 2.654
Liang Wang,Da-Gang Guo
A UV-curable poly(butyl fumarate) (PBF)/poly(propylene fumarate)-diacrylate (PPF-DA) hybrid material with good performance for LED encapsulation is introduced in the paper. They have been prepared by radical polymerization using PBF and PPF-DA macromers with a UV curing system. PBF and PPF-DA were characterized by Fourier-transform infrared (FT-IR) and H-nuclear magnetic resonance (1H NMR). The thermal behavior, optical and mechanical properties of the material were examined by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), ultraviolet-visible spectroscopy (UV–vis), and a material testing system mechanical testing machine, respectively. The results indicated that the hybrid material has a suitable refractive index (n= 1.537) and high transmittance (99.64% in visible range) before/after thermal aging. With the increasing of the double bond ratio from 0.5 to 2, the water absorption ratios of the prepared encapsulation material were 1.22%, 1.87% and 2.88%, respectively. The mechanical property experiments showed that bonding strength was in the range of 1.86–3.40 MPa, tensile-shear strength ranged from 0.84 MPa to 1.57 MPa, and compression strength was in the range of 5.10–27.65 MPa. The cured PBF/PPF-DA hybrid material can be used as a light-emitting diode (LED) encapsulant, owing to its suitable refractive index, high transparency, excellent thermal stability, lower water absorption, and good mechanical properties.Keywords:poly(butyl fumarate)-based polymer;composites;characterization;UV-curing;LED encapsulant
研究领域:
材料科学
·
高分子化学
·
光电子学
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产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Yang Zhang,Ting Li,Zhining Xie,Jiarui Han,Jun Xu,Baohua Guo
Novel biobased multiblock polyesters poly(2,5-furandimethylene succinate)-b-poly(butylene succinate) (PFS-PBS) containing PFS and PBS blocks were synthesized in a full composition range via chain-extension reaction of dihydroxyl terminated poly(2,5-furandimethylene succinate) (HO-PFS-OH) and poly(butylene succinate) (HO-PBS-OH) prepolymers. High molecular weight polyesters were obtained, and the stability of double bonds in 2,5-bis(hydroxymethyl)furan was guaranteed via this preparation procedure. The obtained copolyesters were characterized with 1H NMR, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, wide-angle X-ray diffraction, and the mechanical properties were also investigated. No transesterfication reaction happened during chain-extension reaction, and the expected multiblock chemical structure was obtained. The PBS block is crystallizable, while the PFS block is nearly amorphous. Crystallization temperature and degree of crystallinity gradually decreased with increasing PFS fraction, but the melting temperature of crystalline samples showed no sharp reduction (109.4–105.2 °C). The crystallization rate also decreased with incorporation of PFS during isothermal crystallization, but the crystallization mechanism remained unchanged at any composition. Finally, the PFS-PBS copolyesters exhibit widely tunable mechanical properties, ranging from semicrystalline thermoplastics to amorphous soft elastomer-like polymers.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Zongpeng Liu,Shaojian Hu,Yuning Zhang,Bencheng Wu,Jianhua Zhu
Synthetic esters are expected to have broad application prospects in the high-end lubrication sectors owing to their fascinating custom-tailored properties. Herein, we synthesized a novel complex polyolester (CPE) via a stepwise esterification procedure using stannous oxide as a heterogeneous catalyst. Response surface methodology coupled with the Box–Behnken design (BBD-RSM) was employed to optimize the experimental parameters and elucidate the interactions among the operating variables on the low-temperature fluidity of CPE. The optimization results indicated that the lowest pour point (−42 °C) could be obtained under the catalyst dosage of 1.2 wt%, the first step reaction temperature of 164 °C, the first step reaction time of 100 min, and the second step reaction temperature of 178 °C. Particularly, there is a significant interactive effect between the catalyst dosage and the second step reaction temperature. Followed by the molecular distillation of the crude ester prepared under the optimal conditions, the refining results revealed that the non-ideal components had been effectively removed and the total acid number of the final product was substantially reduced to below 0.1 mg KOH/g. The molecular structures of the as-synthesized esters were confirmed by FT-IR, NMR, GPC, ESI–MS, and TGA characterization and their physicochemical and tribological properties were also evaluated according to standard methods. In view of the unique molecular structural design, the developed CPE displayed plentiful prominent technological specificities, which makes it plausible to be served as a potential high-performance base stock. Therefore, the findings of this study may provide some valuable insights for expanding the application scope of synthetic esters into various special industrial scenarios.
研究领域:
化学工程
·
材料科学
·
润滑技术
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Kaihao Chen,Tianwen Bai,YuLing Lin,Jun Ling,Xufeng Ni
Chemical synthesis of polymers from carbon dioxide (CO2) has been attracting a continuous amount of attention. This contribution explores the copolymerization of ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVL) synthesized from CO2 and 1,3-butadiene with various cyclic carbonates (CC) derived from CO2 and biomass diols. Following the “scrambling polymerizations” mechanism, EVL units are incorporated into polycarbonate backbones, resulting in random poly(ester-co-carbonate) P(EVL-co-CC) with functionalizable C═C double bonds. Kinetic studies and characterizations are conducted by NMR, MALDI-ToF MS, and SEC techniques. The obtained degradable P(EVL-co-CC)s having varying topologies, CO2 and C═C double bond contents, and glass transition temperatures are suitable for diverse applications. Modification in situ or via a postpolymerization “thiol–ene” reaction produces a copolymer with tunable tensile strength and amphiphilic and hydrophilic properties. This work presents an advancement in the utilization of CO2 to synthesize functional poly(ester-co-carbonate)s, contributing to the development of sustainable and green polymer chemistry.
研究领域:
材料科学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Ying Gao,Yong Liu,Lingling Gao,Jinxing Long
An effective strategy is proposed here for transfer hydrogenation of alkyl levulinate to γ-valerolactone (GVL) using a UiO-66 framework modified with phosphotungstate ionic liquid (UiO-66@IL(HPW)). Due to the intensive influence of ionic liquid fragment, the modification significantly enhances the catalytic activity of UiO-66@IL(HPW), leading to a complete conversion of ethyl levulinate with over 93.1% selectivity for GVL. Characterizations techniques, including XRD, N 2 absorption/desorption, SEM, FT-IR, pyridine FT-IR, NH 3 -TPD and CO 2 -TPD, confirm that while the basic structure of UiO-66-NH 2 is insignificantly changed, the introduction of the ionic liquid greatly improves the acidic/base properties of the catalyst. XAFS and XPS results reveal an intensive interaction between the N and W species in UiO-66@IL(HPW), and the formed W-N/O moiety is responsible for the enhanced catalytic activity. In addition, a plausible catalytic mechanism is proposed based upon in situ DRIFTS and density functional theory (DFT) calculations, highlighting the crucial role of ionic liquid fraction within the UiO-66 ligand. Therefore, this work would contribute to the valorization of biochemicals.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2024
·
IF 9.3
Nan Hu,Lijuan Su,Hongyan Li,Ning Zhang,Yongqin Qi,Hongliang Wang,Xiaojing Cui,Xianglin Hou,Tiansheng Deng
Various excellent catalysts have been explored for the methanolysis of polycarbonate (PC), but it is still challenging to develop green and economical catalysts for solvent-free PC methanolysis to recover both bisphenol A (BPA) and dimethyl carbonate (DMC). Herein, green, efficient and solvent-free degradation of PC to BPA and DMC was achieved using urea as a cheap green catalyst. At 140 °C for 3 h, PC was completely degraded to BPA and DMC with yields of 93.4% and 74.7%, respectively. A possible catalytic degradation mechanism of PC was proposed by kinetic experiments and NMR, where urea, methanol and carbonate formed a six-membered ring in the reaction. It was found that the increase of urea concentration significantly reduced the activation energy, which was attributed to the fact that the increase of urea concentration made the six-membered ring easier to form and activated the carbonate bond. The degradation system can be reused directly up to 10 times and 100% degradation rate can be maintained. This work provides a simple, green and economical method for industrial PC recycling.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Jun Yan,Pingfan Xu,Peikun Zhang,Haojun Fan
Seeking a facile strategy to synthesize efficient, inexpensive and robust flame retardants which endow the polyurethane (PU) composites with desirable flame retardancy and mechanical property remains compelling but challenging. Here, we report the surface modification of commercial ammonium polyphosphate (APP) by 3-amino-1,2-propanediol in water solution to construct a novel organic–inorganic hybrid. The functionalized APP (FAPP) with multi-hydroxyl, which acts as both intumescent flame retardants and crosslinking agent, was covalently introduced into solvent-free PU composite via a thermo-curing process. Interestingly, FAPP exhibits good compatibility and strong interfacial interactions within PU matrix, which in turn significantly enhances the tensile strength (~40%) of the resultant PU composite, but without compromising the flexibility. With the incorporation of 15 wt% FAPP, the PU composite reaches a limiting oxygen index of 27.2%, and passes UL-94 V-0 rating. Meanwhile, the peak heat release rate and total heat release are respectively decreased by 64.5% and 37.8% over that of pristine PU, which is far superior to original APP. The high flame-retardant efficiency primarily results from the formation of compact and intumescent char layers in condensed phase. Accordingly, our practice may be extendable to the implementation in other high-performance flame-retardant polymer-matrix composites.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2021
·
IF 5.279
Haixia Xu,Xiaofeng Li,Xuan Xin,Lan Mo,Yucong Zou,Guanglei Zhao
In this paper, an enzymatic route for synthesizing phenolic glycoside azelaic acid esters was successfully set up via lipase-catalyzed esterification and transesterification. Among the lipases tested, Candida antarctica lipase B (Novozyme 435) showed the highest activity in catalyzing esterification and Thermomyces lanuginosus (Lipozyme TLIM) gave the highest substrate conversion in catalyzing transesterification for the synthesis of ester. The addition of 4A molecular sieves into the reaction system is found to be an effective method for in situ absorption of the byproduct water and methanol, with which the substrate conversions of the enzymatic esterification and transesterification were 98.7 and 95.1%, respectively. Also, the main product ratios in transesterification were above 99.0% with lipozyme TLIM as a catalyst because the hydrolysis reaction was hindered. The results of the physical and biological properties indicate that all esters had higher Clog p values than their parent compounds. Also, the esters showed higher intracellular tyrosinase inhibitory and depigmentating activities than phenolic glycosides, azelaic acid (AA), and their physical mixtures due to their higher membrane penetration and tyrosinase inhibitory effects. In particular, piceid 6″-O-azelaic acid ester (PIA) showed the strongest inhibitory effect against melanin production. Its inhibitory rate was 77.4% at a concentration of 0.25 mM, about 4.2 times higher than that of arbutin (18.5%).
研究领域:
生物化学
·
药理学
·
化妆品科学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）