APL Materials
·
2020
·Vol. 8
·期 6
·
IF 3.819
Li Xiu,Chen Chen,Zhang Faqiang,Huang Xintang,Yi Zhiguo
Photostrictive effect that has been discovered for over half a century is getting renewed interest in recent years in view of the great potentials for optomechanical applications. Ferroelectric materials represented by lead lanthanum zirconated titanate have been widely studied in this field because of their relatively large photostriction and fast photoresponse, but their wide bandgaps with limit response to visible light hinder further practical application. Here, visible-light-driven photostrictions of the order of 10 −3 are discovered in Bi(Ni 2/3 Nb 1/3 )O 3 –PbTiO 3 (BNNPT) ferroelectric solid solutions. Three BNNPT compositions with different phase structures, exhibiting notably different piezoelectric and photovoltaic properties, are selected to conduct the photostriction investigation, and their analogous photostrictive behaviors contradict with previous acknowledgment that the photostriction of ferroelectrics originates from the photovoltage-induced inverse piezoresponse. The nonuniform shifts of the XRD diffraction peaks under external laser illumination and the redshifts of the laser power dependent Raman modes disclose that the photostriction is mainly attributed to the light-induced distortion of BO 6 octahedra. This study sheds insight into the mechanism of the photostriction of ferroelectrics.
✓ 已验证
产品关联
DOI
高影响因子
Biomass Conversion and Biorefinery
·
2021
·Vol. 13
·期 9
·8115-8121
·
IF 4.987
Ren Dezhang,Jiang Xuelei,Zhang Nahui,Duo Jia,Norinaga Koyo,Huo Zhibao
Production of pyridine derivatives from bio-based feedstocks instead of fossil fuels is a promising strategy. The development of effective heterogeneous catalysts and mild reaction systems for pyridinization of renewable biomass derivatives remains a huge challenge. In this article, a direct and environment-friendly method was reported to produce 3-hydroxypyridine from bio-based furfural in water over a Raney Fe catalyst. Raney Fe exhibited an efficient catalytic performance for activation of the aldehyde group of furfural and afforded an 18.2% yield of 3-hydroxypyridine at 120 °C with ammonia as N source. The polymerization of furfural on the catalyst in hot water was the main cause of deactivation, which was verified by the scanning electron microscope (SEM), X-ray diffraction (XRD), and N 2 adsorption and desorption analysis. A possible mechanism for this reaction was also proposed. This study provides a new way for academia and industry to realize the synthesis of nitrogen-containing chemicals from biomass and its derivatives.
✓ 已验证
产品关联
DOI
高影响因子
OPTIK
·
2021
·
IF 2.443
Jimin Ding,Pengfei Zhu,Ziqing Li,Zhenyan Wang,Li Ai,Jianfu Zhao,Fapeng Yu,Xiulan Duan,Huaidong Jiang
K 2 TiYb(PO 4 ) 3 microcrystals with langbeinite structure have been prepared for the first time by solid state reaction. Pure K 2 TiYb(PO 4 ) 3 sample with size of 10–20 µm was obtained when the calcination temperature was 1000 °C. The microstructure and performance of the microcrystals are studied by using X-ray photoelectron spectra (XPS), FTIR and Raman spectra , UV-Vis diffuse reflectance spectra, and upconversion photoluminescence spectra. The electronic structure analysis by XPS shows that K 2 TiYb(PO 4 ) 3 has the stronger Ti-O ionic band and weaker P-O covalent band than KTiOPO 4 . The absorption peaks at 911 and 975 nm are assigned to the transition of Yb 3+ from 2 F 7/2 (0) to 2 F 5/2 (2′) and 2 F 5/2 (0′) levels, respectively. Under the excitation of 980 nm laser, K 2 TiYb(PO 4 ) 3 produces polychromatic luminescence: strong blue emission at 480 nm and weak red emission at 653 nm, and the corresponding lifetimes are 268.6 and 275.1 μs, respectively. The strong blue emission is assigned to the cooperative luminescence between Yb 3+ -Yb 3+ pairs, and the red emission is related to defects in the samples. All the CIE color coordinates for the langbeinite-type compounds are located in the blue region, which shows their great potential as blue upconversion photoluminescence materials.
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Yongdong Liu,Yonghong Wu,Jianqi Yao,Jiajie Yin,Jing Lu,Jie Mao,Min Yao,Faliang Luo
To explore the effects of end groups on the confined crystallization of an alkyl chain, 3-pentadecylphenol (PDP) was infiltrated into the anodic aluminum oxide template (AAO) to investigate the melting and crystallization behaviors of PDP in a nanoconfined environment. Wide-angle X-ray diffraction (WAXD) found that the solid–solid phase transition of PDP occurred under confined conditions, and the absence of the (00L) reflections indicated that the stacking of the end groups of the alkyl chain layered structure was seriously disturbed. Thermal analysis (TG) showed that the thermal stability of the confined samples decreased due to the confinement effect, and the introduction of end groups made the confinement effect more obvious. Differential scanning calorimeter (DSC) results well reflected the space–time equivalence in the PDP crystallization processes, i.e., the solid–solid phase transition can be achieved by reducing the cooling rate or confining PDP in the nanometer space. Compared with C15, the introduction of the end groups with a phenol ring led to the disappearance of the solid–solid phase transition of an alkyl chain at high cooling rates. In the confined environment, the introduction of the end groups with a phenol ring caused the melting double peaks of the alkyl chain to become a single melting peak, and it also caused the disappearance of the surface freezing monolayer for alkyl chains. Through the analysis of crystallinity, it was found that AAO-PDP was more sensitive to AAO pore size changes than AAO-C15, the Xc of AAO-PDP had a good linear relationship with the pore size d, but the Xc of the AAO-C15 had a nonlinear relationship with the pore size d. Attenuated total reflection (ATR)-IR proved that in the confined environment, the order of the alkyl chain decreased and the degree of chain distortion increased.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Experimental and Therapeutic Medicine
·
2021
·Vol. 22
·期 6
·1-9
·
IF 2.447
Yue-Yuan Chen,Xiao-Jie Yan,Xiao-Hua Jiang,Feng-Lai Lu,Xue-Rong Yang,Dian-Peng Li
Aberrant destruction of the articular extracellular matrix (ECM) has been considered to be one of the pathological features of osteoarthritis (OA) which results in chondrocyte changes and articular cartilage degeneration. The MAPK signaling pathway serves a key role by releasing cartilage‑degrading enzymes from OA chondrocytes. However, the use of MAPK inhibitors for OA is hindered by their potential long‑term toxicity. Vicenin 3 is one of the major components of the Jian‑Gu injection which is effective in the clinical treatment of OA. However, its potential impact on OA remain poorly understood. Therefore, the present study aimed to assess the effects of vicenin 3 on interleukin (IL)‑1β‑treated SW1353 chondrocytes, which mimic the microenvironment of OA. These chondrocytes were pretreated with vicenin 3 (0, 5 and 20 µM) for 1 h and subsequently stimulated with IL‑1β (10 ng/ml) for 24 h. Nitric oxide (NO) production was measured using the Griess reaction, whereas the production of prostaglandin E2 (PGE2), matrix metalloproteinases (MMPs), A disintegrin‑like and metalloproteinase with thrombospondin motifs (ADAMTSs), collagen type II and aggrecan were measured using ELISA. The mRNA expression of MMPs and ADAMTSs were measured using reverse transcription‑quantitative PCR. The protein expression levels of MAPK were measured using western blotting. Vicenin 3 was found to significantly inhibit IL‑1β‑induced production of NO and PGE. Increments in the expression levels of MMP‑1, MMP‑3, MMP‑13, ADAMTS‑4 and ADAMTS‑5 induced by IL‑1β, in addition to the IL‑1β‑induced degradation of collagen type II and aggrecan, were all reversed by vicenin 3 treatment. Furthermore, vicenin 3 suppressed IL‑1β‑stimulated MAPK activation, an effect that was similar to that exerted by SB203580, a well‑known p38 MAPK inhibitor. In conclusion, vicenin 3 may confer therapeutic potential similar to that of the p38 MAPK inhibitor for the treatment of OA.
✓ 已验证
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Mingjie Chen,Rui-Min Li,Troy Runge,Jin Feng,Jing Feng,Songnan Hu,Qing-Shan Shi
Cellulose acetate is one of the oldest synthetic thermoplastic polymers and has various applications including usage as films, fibers, and membrane products. Traditionally, cellulose acetate is prepared by reacting cellulose with acetic anhydride in acetic acid using sulfuric acid as a catalyst. This process suffers from extensive depolymerization of the cellulose molecules and corrosion of the equipment from the use of the acidic solvent and catalyst. Herein we present an acid-free cellulose acetylation process using vinyl acetate as both the reactant and reaction medium and 1-ethyl-3-methylimidazolium acetate as the catalyst. The obtained cellulose acetate was confirmed by FTIR, NMR, and XRD studies. Additionally, the reaction kinetics, mechanism of the process, and properties of the obtained cellulose acetate were studied. Cellulose triacetate was obtained by our process within 2 h at 90 °C. The reaction kinetics was described with the classical pseudo-first-order rate expression of heterogeneous cellulose acetylation. The reaction mechanism was shown to be a peel-off mechanism similar to that of cellulose acetylation by the traditional acetic acid process. The molecular weight of the cellulose acetate produced by this new process was significantly higher than that from the traditional acetic acid process because of the absence of strong acids, which can depolymerize cellulose. In summary, we describe a new acid-free process to produce cellulose acetate that limits cellulose depolymerization and avoids the use of corrosive chemicals.
✓ 已验证
产品关联
DOI
高影响因子
Brazilian Journal of Otorhinolaryngology
·
2019
·Vol. 85
·期 6
·705-715
·
IF 1.603
Chen Jing,Li Hai Liang,Li Bo Bo,Li Wei,Ma Dong,Li Yong He,Liu Tao
Introduction: Serum- and glucocorticoid-inducible kinase 3, a serine/threonine kinase that functions downstream of the PI3K signaling pathway, plays a critical role in neoplastic processes. It is expressed by various tumors and contributes to carcinogenesis. Objective: The objective was to investigate serum- and glucocorticoid-inducible kinase 3 expression in nasopharyngeal carcinoma, to study the anti-tumor effects of serum- and glucocorticoid-inducible kinase 3 shRNA by inhibiting its expression in nasopharyngeal carcinoma cells and to discuss the potential implications of our findings. Methods: Serum- and glucocorticoid-inducible kinase 3 protein expression in nasopharyngeal carcinoma cell lines (CNE-1, CNE-2, HNE-1, HONE-1, and SUNE-1) and the human immortalized nasopharyngeal epithelium cell line NP69 were assayed by western blotting. Serum- and glucocorticoid-inducible kinase 3 expression in 42 paraffin-embedded nasopharyngeal carcinoma tissues were performed by immunohistochemistry. MTT assay, flow cytometry, and scratch tests were performed after CNE-2 cells were transfected with the best serum- and glucocorticoid-inducible kinase 3 shRNA plasmid selected by western blotting using lipofectamine to study its effect on cell proliferation, apoptosis, and migration. Results: Serum- and glucocorticoid-inducible kinase 3 was overexpressed in human nasopharyngeal carcinoma tissues and cells. Serum- and glucocorticoid-inducible kinase 3 expression decreased markedly after CNE-2 cells were transfected with the serum- and glucocorticoid-inducible kinase 3 shRNA, leading to strong inhibition of cell proliferation and migration. In addition, the apoptosis rate increased in CNE-2 cells after serum- and glucocorticoid-inducible kinase 3 knockdown. Conclusion: Serum- and glucocorticoid-inducible kinase 3 expression was more frequently observed as the nasopharyngeal epithelium progresses from normal tissue to carcinoma. This suggests that serum- and glucocorticoid-inducible kinase 3 contributes to the multistep process of NPC carcinogenesis. Serum- and glucocorticoid-inducible kinase 3 represents a target for nasopharyngeal carcinoma therapy, and a basis exists for the further investigation of this adjuvant treatment modality for nasopharyngeal carcinoma.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2019
·
IF 3.771
Fuzhou Wang,Guoyong Xu,Qingshan Li,Ryo Tanaka,Yuushou Nakayama,Takeshi Shiono
The first example of a 3-alkene polymerization has been successfully achieved with 3-heptene in the presence of phenyl-substituted α- diimine nickel precatalysts activated by dMMAO, and compared with the corresponding linear alkenes, i.e., 1-pentene, 2-hexene and 4-octene polymerizations. The microstructures of the produced poly(3-heptene), which consists of ethyl , propyl and butyl branches indicated the 3,4- and 4,3-insertion, followed by chain-walking, with incorporation of a small fraction of long methylene sequences of 1,7-enchainment via monomer-isomerization. Late-transition metal catalyzed polymerization reactions of internal alkenes to synthesize novel polyolefin materials are highly important and also highly challenging. Upon activation with dried modified methylaluminoxane (dMMAO), the first example of a 3-alkene polymerization has been successfully achieved for 3-heptene catalyzed by phenyl-substituted α- diimine nickel complexes in comparison, and compared with the polymerizations of the corresponding linear alkenes, i.e., 1-pentene, 2-hexene and 4-octene. The results indicate that the polymerization of 3-heptene was achieved via chain-walking to generate branched amorphous polymers with glass transition temperature of ca. −68 °C. The microstructures of the produced poly(3-heptene) indicated the 3,4- and 4,3-insertion followed by chain-walking, the latter being predominant. The NMR analyses of the polymers showed that the obtained poly(3-heptene) possessed ethyl, propyl and butyl branches and a small amount of the long methylene sequence of 1,7-enchainment via monomer-isomerization. The branches structures were significantly dependent on the polymerization temperature, and the content of propyl branches derived from 3,4-insertion decreased with an increase in the polymerization temperature.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY
·
2019
·
IF 4.027
Jie Yang,Pingping Zhang,Yuheng Hu,Teng Liu,Jie Sun,Xiaojing Wang
Alzheimer's disease, a neurodegenerative illness, has the extremely complex pathogenesis. Accumulating evidence indicates there is a close relationship between several enzymes and Alzheimer's disease. Various substituted 3-arylcoumarin derivatives were synthesised, and their in vitro activity, including cholinesterase inhibitory activity, monoamine oxidase inhibitory activity, and antioxidant activity were investigated. Most of the compounds exhibited high activity; therefore 3-arylcoumarin compounds have the potential as drug candidates for the treatment of Alzheimer's disease.
✓ 已验证
DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2019
·
IF 5.256
Yuze Xie,Mingwei Wang,Xi Chen,Shufen Wang,Dandan Han,Yehong Han,Hongyuan Yan
A facile and efficient method for the determination of triazine herbicides in tomato samples was developed by employing 3-aminophenol-glyoxylic acid resin microspheres as a solid-phase extraction adsorbent followed by high performance liquid chromatography analysis. These resin microspheres were synthesized by a simple green precipitation polymerization method, and a range of functional groups (hydroxyl, amino, carboxylic group) were introduced through the 3-aminophenol and glyoxylic acid components. The as-prepared resin microspheres were characterized by scanning electron microscopy, Fourier transform infrared spectrometry , and thermal gravimetric analyzer. The resin microspheres exhibited a good adsorption rate, large adsorption amount, and short adsorption equilibrium time (almost in ∼5 min). Under the optimal extraction and determination conditions, a good linearity was obtained in the range of 0.025–7.5 μg g −1 (r 2 ≥ 0.9997) for atraton , ametryn , and prometryn . The limits of detection of atraton, ametryn, and prometryn were 0.57, 0.75, and 1.06 μg kg −1 , respectively. The intra-day and inter-day precisions expressed as relative standard deviations were in the ranges of 1.8–3.2% and 1.7–4.1%, respectively. In addition, the recoveries at three spiked levels ranged from 85.1 to 97.7% with the relative standard deviation ≤ 5.4% (n = 3). This novel method is simple and accurate and has proved to be a reliable alternative method for the determination of triazine herbicides in tomato samples.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2018
·
IF 3.235
Hongrui Wang,Min Gao,Yan-an Zhu,Huawei Zhou,Huating Liu,Lin Gao,Mingxing Wu
Carbon molecular sieve is introduced as flexible supercapacitor electrode for the first time. The carbon molecular sieve electrode generates a specific capacitance of 108.0 F·g −1 and demonstrates an excellent stability with 98.5% preservation of its initial capacitance after 10,000 charging-discharging cycles. To further enhance the electrochemical performance, a flexible 3-D structured composite electrode is synthesized via an electrochemical polymerization method by depositing poly 3,4‑ethylenedioxythiophene film on the carbon molecular sieve surface, denoted as carbon molecular sieve@poly 3,4‑ethylenedioxythiophene. The specific capacitance of the composite electrode is up to 126.0 F·g −1 , higher than both poly 3,4‑ethylenedioxythiophene (115.7 F·g −1 ) and carbon molecular sieve (108.0 F·g −1 ). Moreover, the flexible composite electrode preserves 96.0% of its initial capacitance after 10,000 charging-discharging cycles at 1.00 A·g −1 . The superior performance of the composite electrode is attributed to the combined merits of the superior conductivity and excellent cycle stability of the carbon molecular sieve and 3-D porous network configuration of the poly 3,4‑ethylenedioxythiophene.
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR RESEARCH
·
2018
·Vol. 26
·期 5
·403-409
·
IF 1.767
Wang Xiaoping,Du Jianghua,Zhang Xin,Jia Deming
A mechano-chemical modification process for waste rubber powder (WRP) was investigated in this paper. 2-Mercatobenzothiozole (accelerator M) was introduced as a peptizer to improve plasticity of WRP, and 3-aminopropyltriethoxysilane (silane coupling agent KH550) was used as a surfactant to further modify the surface of plasticized rubber powder (PRP) to improve interfacial bonding with epoxidized natural rubber (ENR). Infrared spectrums showed that the WRP generated more oxygen-containing groups by mechanical forces in the presence of accelerator M and then grafted amino groups with KH550. The mechano-chemical process with accelerator M changed the structure of WRP obviously shown by sol fraction and microstructure of PRP, which increased the mechanical properties and crosslink density of full rubber powder vulcanizates. After further modified by KH550, the modified rubber powder (MRP) had a positive chemical interfacial bonding with ENR, changing the fracture surface and improving the mechanical properties of vulcanizates. The cure characteristics of the vulcanizates also illustrated that accelerator M and KH550 participated in the vulcanization process increasing the curing efficiency. The best mechanical properties of ENR/MRP vulcanizates were better than the neat ENR vulcanizates. It indicated that the mechano-chemical process with accelerator M and KH550 will be a potential method to reclaim WRP.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）