JOURNAL OF DENTISTRY
·
2020
·
IF 3.242
Jiaxue Yang,Jiadi Shen,Xinyi Wu,Feng He,Haifeng Xie,Chen Chen
Objectives This study investigated the effects of the surface conditioning of nano-zirconia fillers with 10-methacryloyloxydecyl dihydrogen phosphate (MDP) and dipentaerythritol penta-acrylate phosphate (PENTA) on the degree of conversion and mechanical properties of Bis-GMA- and UDMA-based resin composites containing the fillers. Methods MDP or PENTA conditioned nano-zirconia fillers were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The conditioned nano-zirconia fillers were then used to prepare Bis-GMA- and UDMA-based resin composites. The bending strength and elastic modulus of the prepared composites were evaluated, and Weibull analysis was adopted to evaluate the reliability of the bending tests. Degree of conversion (DC) was measured by FTIR. Results FTIR and XPS analysis confirmed formation of Zr O P bonds in the MDP-conditioned and PENTA-conditioned zirconia fillers. MDP-conditioning and PENTA-conditioning increased bending strength of Bis-GMA-based composites (100.70 ± 7.15 MPa, 98.65 ± 4.76 Mpa) and UDMA-based composites (99.02 ± 4.45 MPa, 99.92 ± 5.78 MPa) compared to the groups with untreated nano-zirconia fillers (Bis-GMA-based, 84.98 ± 5.13 MPa; UDMA-based, 88.24 ± 4.61 MPa). The same trend was observed for the Weibull modulus ( m ) and elastic modulus. The MDP/PENTA conditioning did not affect the DC of the composites. Conclusion MDP or PENTA conditioning of nano-zirconia fillers improved the mechanical properties of the composite compared to the composites containing untreated nano-zirconia fillers; however, it did not affect DC. Clinical significance Mixing MDP- or PENTA-conditioned nano-zirconia fillers directly with gamma-MPS-conditioned silica to the resin composite has the potential to improve the composite’s mechanical properties.
研究领域:
牙科材料学
·
高分子化学
✓ 已验证
DOI
PubMed
高影响因子
Polymer Chemistry
·
2017
·Vol. 8
·期 19
·3013-3021
·
IF 5.375
Zhi Qiao,Teng Qiu,Weiwei Liu,Liangdong Zhang,Jinqiang Tu,Longhai Guo,Xiaoyu Li
A clean method for preparing ABCBA penta-block terpolymers was developed in a surfactant and organic solvent free emulsion system via one-pot RAFT polymerization. The prepared ABCBA penta-block terpolymers show large fracture tensile strain, low permanent set and potential application as elastomer materials. During the preparation process, polyacrylic acid (PAA) was firstly synthesized as the A block via RAFT polymerization in water in the presence of a dual-functional RAFT agent. Subsequently, we selected a partially water-soluble monomer 2,2,2-trifluoroethyl acrylate (TFEA) to synthesize the B block, and ABA tri-block copolymers could be obtained via organic solvent free RAFT emulsion polymerization. Using the ABA tri-block copolymers as a surfactant, the ABCBA penta-block terpolymers were further synthesized using 2,2,3,4,4,4-hexafluorobutyl acrylate (HFBA) as the third monomer in an organic solvent free system. It has been found that the emulsification efficiency of the ABA tri-block copolymers is higher than that of the corresponding AB di-block copolymers. The assembly mechanism of penta-block terpolymers to form a tri-layer core–shell latex particle was proposed and confirmed by TEM images. Finally, we obtained a transparent and hydrophobic elastomeric film by directly casting the synthesized penta-block terpolymer latexes and subsequent heat treatment. The films have excellent mechanical properties and water resistance.
研究领域:
高分子化学
·
功能材料
·
纳米材料
·
胶体与界面科学
·
可持续化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Xingling Zhao,Xue Zhou,Wanyan Xing,Zhimin Yuan,Kaili Wang,Qihang Zhang,Yulong Shan,Jiani Liu,Lin Ju,Zaiyong Jiang,Hong He
CO is a ubiquitous air pollutant, frequently encountered in the fields of automotive exhaust purification, especial in the cold-start-emission stage. Pt based catalysts are widely used to purify CO into CO 2 owing to their exceptional performance. But they can be few excited to exhibit reasonable catalytic activity due to the low temperature at the cold-start-emission stage. In exhaust gas purification catalysts used by fossil fuel-based vehicles, Al 2 O 3 is used frequently. But there are rarely reports of Pt loaded Al 2 O 3 catalysts achieving feasible activity of CO oxidation at room temperature. Herein, we prepared Cu x Pt y alloy/Al 2 O 3 catalysts (with high penta-coordinated Al 3+ (Al V )), Al V centers as binding sites for Cu 3 Pt 1 alloys on Al 2 O 3 enable the high dispersion and stability of Cu 3 Pt 1 alloy. The adsorption capacity of O 2 and CO molecules on Cu 3 Pt 1 surface are stronger than the case on Pt surface, which may make O 2 and CO molecules more easily activated, making the CO oxidation reaction easier. In addition, the desorption of CO 2 from Cu x Pt y surface is easier compared to that on Pt surface, increasing the frequency of use of active sites there. Therefore, this Cu 3 Pt 1 /Al 2 O 3 catalyst exhibits 100 % conversion of CO with a GHSV of 6×10 3 mL·g −1 cat ·h −1 at room temperature. This work provides a feasible guideline for the design and synthesis of Pt loaded Al 2 O 3 catalysts toward room temperature CO oxidation.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JACS Au
·
2023
·
IF 8
Qi Yang,Xiujuan Gao,Faen Song,Xiaoxing Wang,Tao Zhang,Pan Xiong,Yunxing Bai,Xingchen Liu,Xiaoyan Liu,Junfeng Zhang,Gang Fu,Yisheng Tan,Yizhuo Han,Qingde Zhang
Selective oxidation of C–H bonds under mild conditions is one of the most important and challenging issues in utilization of energy-related molecules. Molybdenum oxide nanostructures containing Mo5+ species are effective for these reactions, but the accurate identification of the structure of active Mo5+ species and the catalytic mechanism remain unclear. Herein, unsaturated penta-coordinated Mo5c5+ with a high fraction in MoOx fabricated by the hydrothermal method were identified as the active sites for low-temperature oxidation of dimethyl ether (DME) by the deep correlation of characterizations, density functional theory calculations, and activity results, giving a methyl formate selectivity of 96.3% and DME conversion of 12.5% at unreported 110 °C. Low-temperature electron spin resonance (ESR) and quasi in situ X-ray photoelectron spectra (XPS) with the designed experiments confirm that the Mo5c5+ species can be formed in situ. Molybdenum located at the pentachronic site is preferable to significantly promote the oxidation of the C–H bond in CH3O* at lower temperatures.
研究领域:
化学
·
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 15
·3490-3500
·
IF 5.686
Mingwei Wu,Wenzhi Li,Xia Zhang,Fengyang Xue,Tao Yang,Liang Yuan
Graphical Methane combustion : Defect-Rich CeO 2 −Al 2 O 3 supported palladium catalysts can prominently improve the dispersion of palladium species and strengthen the concentration of active surface oxygen species, resulting in excellent catalytic activity for methane combustion. In heterogeneous catalysis, the strong interaction between metal and support can significantly modulate the electronic properties of the metals and play a crucial role in metal particle dispersion and morphology. Herein, a facile strategy was utilized to fabricate highly dispersive palladium catalysts supported on defective Al 2 O 3 −CeO 2 for lean methane oxidation. Ceria was immobilized on the coordinatively unsaturated Al 3+ penta sites of γ-alumina activated by pre-reduction to fabricate hybrid-oxide support (abbreviated as RAl 2 O 3 −CeO 2 ), and then Pd precursor was uniformly deposited on the defective surface. Such a RAl 2 O 3 −CeO 2 interface can effectively upgrade the dispersion of deposited palladium species and improve the concentration of reactive oxygen species owing to strong electronic interactions, invoking a superior catalytic activity for lean methane oxidation. After loading 1.0 wt% palladium, Pd/RAl 2 O 3 −CeO 2 exhibited a 90 % methane conversion at 328 °C under the space velocity of 60,000 mL g −1 h −1 , far lower than that of bare 1.0 wt% Pd/RAl 2 O 3 (400 °C). In addition, Pd/RAl 2 O 3 −CeO 2 catalyst showed an excellent hydrothermal stability under the harsh conditions (600 °C, water vapor)for 120 h without obvious deactivation. The reaction pathway of total methane combustion was elucidated by in situ DRIFTS. The crucial intermediate compositions (carbon oxygenates and carbonate)on Pd/RAl 2 O 3 −CeO 2 surface are more readily oxidized into CO 2 and H 2 O. This work provides an effective interface-promoted strategy to develop efficient and durable palladium catalysts for many challenging reactions.
研究领域:
催化化学
·
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Guangliang Niu,Fangyan Liu,Yun Yang,Yunzhi Fu,Wei Wang
Multimetallic nanomaterials have many applications. The controlled synthesis of multimetallic nanomaterials is highly desired. We report a study on using penta-fold twinned (PFT) Au nanorods (NRs) as seeds to synthesize PFT Pd-Au-Pd segmental NRs. The results show that the different crystal structures of seeds, I − and cetyltrimethylammonium bromide (CTAB) significantly affect the deposition of Pd on seeds surface. The PFT Pd-Au-Pd segmental NRs showed excellent surface-enhanced Raman scattering (SERS) performance and improved catalytic activity. Our research is of great significance for the synthesis of similar nanostructures, and we also shown that PFT Pd-Au-Pd segmental NRs might have potential applications in studying the process of organic reaction.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
LIFE SCIENCES
·
2025
·
IF 5.1
Qing Li,Mei Zhou,Ying Yang,Yangming Jiang,Chao Chen,Enming Hu,Jialin Chen,Daoping Wang
Overexpression of EphB3 has been documented across various cancers and essential for cell proliferation, survive and metastasis, making it a valuable therapeutic target. In this study, a series of novel penta-1,4-dien-3-one and quinoxaline conjugates were designed and synthesized using pharmacophore fusion strategies to explore potential EphB3 inhibitors. CCK-8 experiments revealed significant anti-cancer activity of most newly synthesized compounds against hepatocellular carcinoma (HCC). Among them, compound W8 displaying the highest inhibitory activity against MHCC97H (IC 50 = 1.87 μM), which arrests MHCC97H cells in the G0/G1 phase and induces apoptosis. Furthermore, compound W8 suppresses tumor growth in an MHCC97H xenograft model in vivo by suppressing phosphorylation level of EphB3 and down-regulating the SRC-AKT signaling pathway, leading to a dose-dependent reduction in tumor volumes and weights, with a 40 mg/kg dose achieving decreases of 68.4 % and 65.3 %, respectively. Given its ability to modulate EphB3 signaling, W8 represents a promising lead compound for further drug development, particularly for cancers characterized by EphB3 overexpression, and may offer new opportunities for targeted therapy in precision oncology.
研究领域:
肿瘤学
·
药物化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2016
·
IF 3.12
Wen-jun Liang,Bin Zhao,Pei-hua Zhao,Cong-yun Zhang,Ya-qing Liu
A novel bridged-cyclotriphosphazene flame retardant , named bisphenol-S bridged penta(anilino)cyclotriphosphazene (BPS-BPP), was synthesized and characterized by fourier transform infrared (FTIR), 1 H NMR and 31 P NMR and mass spectroscopy (MS). Then, BPS-BPP was used to flame retard epoxy resin (EP, diglycidyl ether of bisphenol-A type). The curing behavior and glass-transition temperature (T g ) of EP/BPS-BPP were investigated by differential scanning calorimetry (DSC). The thermogravimetric analysis (TGA) results showed that the incorporation of BPS-BPP improved the thermal stability of EP at high temperature region. Limiting oxygen index (LOI) value of EP sample increased to 29.7% with limited amount of 9 wt% BPS-BPP. The peak of heat release rate (PHRR), total heat release (THR), total smoke production (TSP) values of the same sample, obtained from cone calorimetry , were declined conspicuously, indicating good flame-retardant and smoke suppression efficiency of BPS-BPP. The flame-retardant mechanism of EP/BPS-BPP thermosets was investigated via analyses of gaseous products and char residues. Based on the aforementioned studies, BPS-BPP was demonstrated as an effective flame retardant for EP due to temperature-dependent and bi-phase flame retardant mechanism.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Junlin Cai,Xinyan Liao,Pingting Li,Qiuxiang Wang,Hongpu Huang,Zixi Lyu,Jing Lin,Shuifen Xie
Surface defects on electrocatalysts can effectively reduce reaction barriers and facilitate the kinetics of hydrogen evolution and oxidation reactions (HER/HOR). However, precisely engineering such surface structures remains a significant challenge. Herein, penta-twinned (PTw) Rh@Pt x core–shell nanobranches (NBs) with intense surface strains were facilely synthesized using PTw Rh NBs as the seeds for overgrowth of active Pt-shells. Through precisely regulating the supply of Pt precursor solution via a micro-syringe pump, the ultrathin Pt-shells conform to and replicate the twin defects of the PTw Rh seeds. Significantly, the shell thickness can be precisely controlled from 1.0, 2.0, and 3.8 to 5.0 atomic layers. Due to the integration of surface twinned defects, compressive strain and the core–shell ligand effect, these Rh@Pt x NBs exhibit superior hydrogen redox electrocatalytic performance compared to state-of-the-art Pt/C. Among the prepared materials, the Rh@Pt 0.83 NBs with a 3.8 atomic layer Pt-shell showed the highest mass activity (2.36 A mg Pt −1 ) and specific activity (6.55 mA cm −2 ) for HER at –0.07 V and presented the lowest overpotential (44 mV) at 10 mA cm −2 , less than half the overpotential of the commercial Pt/C (98 mV). In terms of HOR, the Rh@Pt 0.83 NBs showed a superior exchange current density (1.97 mA cm −2 ), approximately 7 times higher than that of Pt/C. Our work provides a facile method to synchronously engineer the Pt-shell thickness and surface defects of Rh@Pt core–shell nanocatalysts for the creation of robust and bifunctional hydrogen redox electrocatalysts.
研究领域:
材料科学
·
电化学
·
纳米技术
✓ 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
·
2015
·
IF 2.729
Xiaolan Zeng,Xuesheng Zhang,Li Qin,Zunyao Wang
The tissue distribution, excretion, and metabolic pathway of 2,2′,4,4′,5-penta-chlorinated diphenylsulfide (CDPS-99) in ICR mice were investigated after oral perfusion at 10 mg/kg body weight (b.w.). Biological samples were extracted and separated and, for the first time, were determined by a novel, sensitive, and specific GC–MS method under the full scan and selected ion monitoring (SIM) modes. The results showed that the concentrations of CDPS-99 in the liver, kidneys, and serum reached a maximum after a one-day exposure and that the CDPS-99 concentration in the liver was the highest (3.43 μg/g). The increase in the concentration of CDPS-99 in muscle, skin, and adipose tissue was slower, and the concentrations of CDPS-99 achieved their highest levels after 3 days of exposure. It was observed that the CDPS-99 concentration in adipose tissue was still very high (0.71 μg/g) after 21 days of exposure, which suggested that CDPS-99 was able to accumulate in adipose tissue. In addition, mouse feces accounted for approximately 75% of the total gavage dose, indicating that CDPS-99 was mainly excreted via mouse feces. Metabolism analysis demonstrated that there were three possible metabolic pathways of CDPS-99 in mice: dechlorination reactions with the formation of tetra-CDPS and hydroxylation and oxidation reactions with the formation of OH-CDPS-99 and chlorinated diphenylsulfone. The present study will help to develop a better understanding of mammalian metabolism of CDPS-99.
研究领域:
环境科学
·
毒理学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Xiaoming Ma,Fang Lin,Xin Chen,Chuanhong Jin
Oxidative etching possesses an enriched flexibility and atomic-level accuracy in tailoring the size, morphology, surface structure, and composition of colloidal nanocrystals toward their catalytic and sensing applications. In this work, we choose one-dimensional penta-twinned Pd nanorods as a model system and apply liquid cell transmission electron microscopy (LCTEM) to investigate the detailed nanoscale etching process under different solution environments, which are DI water/e-beam (weakly oxidative), sodium chloride (NaCl) solution/e-beam (moderately oxidative), and ferric chloride (FeCl3) solution/e-beam (strongly oxidative), respectively. Increasing the oxidative strength of solution alone accelerates the dissolution kinetics and drives the system from the (near)-equilibrium etching, where nanorods appear in flat and low-indexed ends (for DI water/e-beam) to nonequilibrium etching with slender tips formed as intermediate products (for FeCl3/e-beam). Under a nonequilibrium etching condition, both symmetric and asymmetric etching occurred, that is, the penta-twinned structure either retained (for symmetric etching) or dissolved to a fourfold-, threefold-, and twofold-twinned and single-crystalline structure (for asymmetric etching), depending on the structural defects-induced strain distribution. The formation of slender tips of different structures can be further understood via energetic analysis and strain relaxation. In particular, in situ LCTEM results were successfully reproduced by flask system-based etching experiments; hence, direct correlations were built between LCTEM and conventional colloidal etching reactions. This work comprehends the present understanding on the synergetic roles of structure characteristics and solution chemistry for the etching of multiply twinned nanoparticles toward their precise controlled synthesis and practical applications.
研究领域:
材料科学
·
纳米技术
·
催化
·
化学工程
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 11
·7465-7481
·
IF 5.044
Xiao Mengyuan,Guo Yingbin,Zhang Jiayue,Liu Yansong,Ren Yuanlin,Liu Xiaohui
Ammonium salt of diethylene triamine penta methylene phosphonic acid (ADTPMPA), a novel flame retardant, was synthesized and grafted on the lyocell fabric to obtain a kind of flame retardant lyocell fabric (FR-lyocell). Then FR-lyocell was coated by Ag nanoparticles (Ag NPs) to fabricate flame retardant and antibacterial lyocell fabric (FR-Ag-lyocell). The elemental composition, surface morphology, combustion behavior and antibacterial activity of the lyocell fabric before and after modification were investigated. The flame retardant and antibacterial mechanism of FR-Ag-lyocell fabric was also analyzed. The limiting oxygen index (LOI) values of FR-Ag-lyocell fabric before and after 20 laundering cycles (LCs) reached 44.8% and 31.3%, respectively. The treated lyocell fabric possessed lower peak of heat release rate (pHRR) and total heat release (THR) values compared with control lyocell fabric. The FR-Ag-lyocell fabric exhibited excellent antimicrobial ability against Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ), even after 10 LCs. These results indicated that FR-Ag-lyocell fabric had durable flame retardant and antibacterial properties. Graphic abstract
研究领域:
材料科学
·
纺织工程
·
化学工程
✓ 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）