Ceramics-Switzerland
·
2024
·Vol. 7
·期 1
·426-435
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IF 2.7
Yuan-Bin Chen,Yu Fan,Shiuan-Ho Chang,Shaobing Shen
In this study, we used solid-state synthesis to prepare Ba[(ZnxCo1−x)1/3(Nb0.5Ta0.5)2/3]O3microwave ceramics for mobile communications. Compared with Ba[Zn1/3(Nb0.5Ta0.5)2/3]O3, in the prepared materials, Co2+substitution with Zn2+improved the Q × f value and enabled densification and sintering at a lower temperature. We used X-ray diffraction (XRD) and scanning electron microscopy (SEM) to analyze the obtained microstructure. Ba[(ZnxCo1−x)1/3(Nb0.5Ta0.5)2/3]O3was found to have a 1:2 ordered hexagonal structure, and its Q × f value increased with the increase in sintering temperature. In this work, excellent microwave dielectric properties—τf= −0.7 ppm/°C, εr= 34.5, and Q × f = 110,000 GHz—were obtained by sintering Ba[(Zn0.3Co0.7)1/3(Nb0.5Ta0.5)2/3]O3at 1400 °C for 5 h.
研究领域:
材料科学
·
电子工程
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高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 29
·10206-10213
·
IF 4.39
Wenyao Zhang,Wenqi Jin,Meng Cheng,Ruonan Zhang,Zhihua Yang,Shilie Pan
Fluorine-containing compounds significantly enrich the diversity of inorganic chemical structures. Here, four alkaline-earth metal difluorophosphates with different space groups, namely NH4Mg(PO2F2)3 (Cmcm) (1), NH4Sr(PO2F2)3 (P) (2), (NH4)2Ba(PO2F2)4 (P2/n) (3) and Ba(PO2F2)2 (I2d) (4), were synthesized and their structures were determined for the first time. 4 is not only the first alkaline-earth-metal difluorophosphate, but also the first difluorophosphate reported to crystallize in the non-centrosymmetric space group I2d of the tetragonal crystal system. All of the three-dimensional (3D) structures of the title compounds consist of isolated (PO2F2)−, AE–O and NH4+ units, while the differences of the cation radius result in various arrangements of the (PO2F2)− units, which leads to diverse crystal structures and the disparate optical anisotropy of the crystals. According to the deep-ultraviolet (DUV) transmittance spectrum, 3 exhibits a short DUV cut off edge (<180 nm). Solid state 19F and 31P magic-angle spinning NMR spectroscopy was used to verify the presence of covalent P–F bonds in 3. The different size effects, as well as the coordination environments of the Mg2+, Sr2+, and Ba2+ cations, on the structures as a whole have been discussed in detail. In addition, the calculated birefringence values were observed to differ from 0.011 to 0.033 for the four compounds.
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高影响因子
Journal of Chemistry
·
2021
·
IF 2.506
Yuqing Wang,Jianming Wu,Yunxia Li,Jing Yang,Long Wang,Anguo Wu,Feihong Huang,Nan Jiang,Can Tang,Yan Li
To investigate the pharmacokinetics of 2, 3, 8-trimethylellagic (TMEA) in rats in vivo and determine the possible effects of the pathological conditions and compatibility, a rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for quantitative determination was developed. TMEA and Artemetin (internal standard, IS) were separated on an Acquity Shim-pack GIST column with a total running time of 7 min using gradient elution at a flow rate of 0.3 mL/min. The intraday and interday relative standard deviations were <9.50%, and the relative error of accuracy was between −5.70% and 2.96%. The calibration curve of TMEA demonstrated good linearity with r2 = 0.9996, with the average recovery changing from 94.77% to 102.47% and the matrix effect from 93.16% to 100.15%. Compared with the normal group, the area under the plasma concentration-time curve from time 0 to the last time of quantifiable concentration (AUC(0 − t)), area under the plasma concentration-time curve from time 0 extrapolated to infinite time (AUC(0 − ∞)), and the maximum concentration (Cmax) of TMEA increased, whereas the time of maximum concentration (Tmax) and apparent clearance (CL/F) remarkably decreased in the TMEA group. With significantly reduced CL/F, AUC(0 − t), AUC(0 − ∞), and Cmax for TMEA were increased approximately one time after combining with 3, 7-Di-O-methylducheside A (DOMA). AUC(0 − t) and Cmax for TMEA in the 2, 3, 8-trimethylellagic-3, 8-dimethoxyellagic acid-2-oxyglucoside (TMEA-DMAG) group were significantly lower than that in the TMEA group with clearly prolonged Tmax and increased CL/F. These findings indicate that the changes in the pharmacokinetic parameters of TMEA may be caused by pathological and combination conditions.
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高影响因子
EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
·
2022
·
IF 7.088
Zhendong Song,Linlin Lou,Guangjin Fan,Lu Liu,Yang Ge,He Liu,Albert S.C. Chan,Xiaolei Zhang,Xiao-Feng Xiong
Oncogene KRAS plays predominant roles in human cancers by regulating cell proliferation , differentiation, and migration. Recent progress revealed that directly target KRAS G12C with allosteric inhibitors that covalently bind to the switch Ⅱ pocket is feasible. Herein, series of pyrrolo[2,3- d ]pyrimidine derivatives were designed and synthesized through systematic structural optimization, leading to the discovery of compound 2-(( S )-1-acryloyl-4-(2-((( 2R , 7aS )-2-fluorohexahydro-1 H -pyrrolizin-7a(5 H )-yl)methoxy)-7-methyl-6-(8-methylnaphthalen-1-yl)-7 H -pyrrolo[2,3- d ]pyrimidin-4-yl)piperazin-2-yl)acetonitrile ( 50 ) with high KRAS/SOS1 inhibitory potency (IC 50 = 0.21 μM) and strong anti-proliferation activities on cancer cells harboring KRAS p.G12C . Compound 50 also exhibited satisfactory selectivity , moderate pharmacokinetic characters, and good anticancer effects in vivo . Meaningfully, the identification of these compounds highlights the necessity of an appropriate conformational constraint for acquiring the applicable binding pose in the cryptic pocket of KRAS, and the results support efforts toward design of KRAS inhibitors with novel skeleton and binding mechanism could be beneficial for targeting the acquired drug resistance.
研究领域:
肿瘤学
·
药理学
·
药物化学
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DOI
PubMed
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2025
·Vol. 40
·期 4
·1169-1175
·
IF 1.1
Qu Yafen,Yu Yanling,Huang Biwu
[2-(3,4-epoxy-cyclohexyl)ethyl]dimethyltert-butylsilane was synthesized, using tert-butyldimethylsilane (TBDMS) and 1,2-epoxy-4-vinylcyclohexane (EVC) as the main raw materials and tris(triphenylphosphine) chlororhodium(I) [RhCl(Ph 3 P) 3 ] as the catalyst. [2-(3,4-epoxy-cyclohexyl)ethyl] dimethyltert-butylsilane is a novel kind of silicon-containing epoxide. The factors affecting the reaction yield, such as catalyst use, reaction time and reaction temperature, were investigated, and the synthesized product was characterized and analyzed by FT-IR and 1 H-NMR. A series of amine-curing resins were prepared with [2-(3,4-epoxy-cyclohexyl)ethyl]dimethyltert-butylsilane, bisphenol A epoxy resin (E-51) and modified amine (593 amine). The mechanical properties of cured splines with the different proportions of amine-curing resins were tested. When the content of 593 amine was 20%, the content of E-51 was 75% and the amount of [2-(3,4-epoxy-cyclohexyl) ethyl] dimethyltert-butylsilane was 5%, the mechanical properties of the cured splines were the best with the tensile strength being 23.3 MPa, the elongation at break being 7.8%, and the Young’s modulus being 421.3 MPa.
研究领域:
高分子化学
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材料科学
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有机合成
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化学工程
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高影响因子
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
·
2020
·Vol. 34
·期 21
·e8899
·
IF 2.2
Hanfeng Jin,Jiuzhong Yang,Aamir Farooq
Rationale Aromatic hydrocarbons play an important role in the formation and growth of polycyclic aromatic hydrocarbon (PAH) and soot particles. Measurements of their absolute photoionization cross-sections (PICSs), that benefit the quantitative investigation of mass spectrometry, are still lacking, however. Methods PICSs of some aromatic hydrocarbons were measured with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Nitric oxide and benzene were chosen as standard references for PICS calibration, since their photoionization cross-sections are well documented in the literature. Binary liquid mixtures of the investigated molecules and their specific solvents were used in the measurements. Results The investigated aromatics include naphthalene, phenanthrene, 1-methylnaphthalene, indene, 2-/3-/4-methylphenylacetylene, 2-methylindene, diphenylacetylene, 1-/2-ethynylnaphthalene and acenaphthylene. Photo-induced fragments from the molecules were also observed with increasing photon energy. Conclusions Based on our measurements and literature data, PICSs of most aromatic molecules have very similar values beyond their ionization energies. However, molecules that contain the phenylacetylene structure have PICSs higher than other aromatics.
研究领域:
分析化学
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质谱学
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大气化学
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环境科学
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DOI
PubMed
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2024
·
IF 4
Hui Wang,Haijun Bi,Jing Wang,Mengru Li,Xin Yao,Xiaoyu Zhang,Marina Rigling,Ning Wang,Xiaochun Wan,Yanyan Zhang,Xiaoting Zhai
Chinese Keemun black tea (KBT) is one of the most renowned black teas worldwide due to its alluring floral/fruity/honey-like odor. However, the key odorants of the so-called Keemun aroma have not been systematically characterized. A comparative sensory-guided flavor analysis was conducted on the aroma compounds in two orthonasally distinguishable KBTs with high and low grades (HG-KBT and LG-KBT). This well-established methodology included the following steps: volatile collection through solvent-assisted flavor evaporation and headspace solid-phase microextraction, aroma identification based on gas chromatography–olfactometry/mass spectrometry, odor contribution calculation according to stable isotope dilution assay, odor activity values (OAVs), and aroma recombination. A total of 42 odorants were characterized, 16 and 10 of which were regarded as key odorants in HG- and LG-KBT, respectively. Among them, dimethyl sulfide, geraniol, β -ionone, 2-/3-methylbutanal, linalool, and 2-methylpropanal showed the highest OAVs and played a pivotal role in ‘ Keemun aroma’. In general, floral odorants had higher OAVs in HG-KBT. In addition, the quantitative changes during the entire preliminary manufacturing step of the tea leaves indicated the great importance of fresh leaves’ quality and withering for the formation of the final aroma quality of the beverage.
研究领域:
食品科学
·
农业
·
化学
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DOI
高影响因子
危险品化学品经营许可证（带存储）