查找使用阿拉丁产品的科研文献

Novel homo- and co-poly(p-phenyene ether sulfone benzimidazole/sulfide sulfone benzimidazole)s: synthesis and properties

Li Zhi-min,Zhang Gang,Li Yan,Yang Jie

The homo- and co-poly(p-phenyene ether sulfone benzimidazole/sulfide sulfone benzimidazole)s (PESI/PPSSI) had been prepared by solution polycondensation of the mixtures of 4,4′-dicarboxydiphenyl ether (DCDPE) and 4,4′-dicarboxydiphenyl sulfide (DCDPS) with 3,3′,4,4′-tetraanmino diphenyl sulfone (TADS) in polyphosphoric acid (PPA). The FT-IR, 1 H-NMR, DSC, TGA, XRD were used to characterize chemical structure and thermal stabilities of the resultant homo- and co-polymers. The inherent viscosities of the resultant polymers were in the range of 0.621–0.982 dl/g at the polymer concentration of 0.5 %. They were found to have excellent thermal properties with glass transition temperatures (T g ) of 386–393 °C, 5 % weight-loss temperature (T 5% ) of 512–525 °C. These polymers showed amorphous nature as charactered by XRD. Most importantly, the resultant polymers possess good solubility that they can be soluble in various aprotic solvents such as N-methyl-2-pyrolidinone (NMP), dimethyl sulfoxide (DMSO) and 1,3-dimethyl-2-imidazolidinone (DMI) and they could be easily formed transparent, tough and flexible membranes by solution casting method. The membranes showed good mechanical properties: the tensile strengths and Young’s Modulus were in the range of 68.8–98.6 MPa and 2.1–2.8 GPa, respectively.

Fe single atoms anchored on fluorine-doped ultrathin carbon nanosheets for sensitive colorimetric detection of p-phenylenediamine

Xiaofang Chen,Min Feng,Xiaoyi Xie,Yi Zhang,Jie Zhang,Xiupei Yang

Single-atom catalysts have attracted enormous research interest in the field of catalysis owing to their remarkable catalytic activity, excellent stability and outstanding atom utilization. Herein, a new single atom based on single Fe atoms on fluorine-doped (Fe–SAs@FNC) ultrathin carbon nanosheets was successfully synthesized by a polymer-assisted heating method. Experimental evidence showed that the resultant Fe–SAs@FNC with Fe–N 4 sites exhibits superior peroxidase-like activity, which oxidizes the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue product in the presence of hydrogen peroxide (H 2 O 2 ). Based on this, an ultrasensitive and highly selective colorimetric detection method for p -phenylenediamine (PPD) in hair dyes and PPD in hair after dyeing was established, which had a wide linear range (0.2–50 μM) and low detection limit (0.07 μM). This method shows satisfactory sensitivity and selectivity.

Inhibitory Effect of Berberine on Broiler P-glycoprotein Expression and Function: In Situ and In Vitro Studies

Yujuan Zhang,Li Guo,Jinhu Huang,Yong Sun,Fang He,Mire Zloh,Liping Wang

Overcoming P-glycoprotein (P-gp) efflux is a strategy to improve the absorption and pharmacokinetics of its substrate drugs. Berberine inhibits P-gp and thereby increases the bioavailability of the P-gp substrate digoxin in rodents. However, the effects of berberine on P-gp in chickens are still unclear. Here, we studied the role of berberine in modulating broilers P-gp expression and function through both in situ and in vitro models. In addition, molecular docking was applied to analyze the interactions of berberine with P-gp as well as with chicken xenobiotic receptor (CXR). The results showed that the mRNA expression levels of chicken P-gp and CXR decreased in the ileum following exposure to berberine. The absorption rate constant of rhodamine 123 increased after berberine treatment, as detected using an in situ single-pass intestinal perfusion model. Efflux ratios of P-gp substrates (tilmicosin, ciprofloxacin, clindamycin, ampicillin, and enrofloxacin) decreased and the apparent permeability coefficients increased after co-incubation with berberine in MDCK-chAbcb1 cell models. Bidirectional assay results showed that berberine could be transported by chicken P-gp with a transport ratio of 4.20, and this was attenuated by verapamil (an inhibitor of P-gp), which resulted in a ratio of 1.13. Molecular docking revealed that berberine could form favorable interactions with the binding pockets of both CXR and P-gp, with docking scores of −7.8 and −9.5 kcal/mol, respectively. These results indicate that berberine is a substrate of chicken P-gp and down-regulates P-gp expression in chicken tissues, thereby increasing the absorption of P-gp substrates. Our findings suggest that berberine increases the bioavailability of other drugs and that drug-drug interactions should be considered when it is co-administered with other P-gp substrates with narrow therapeutic windows.Keywords:berberine;P-glycoprotein;inhibition;MDCK-chAbcb1 cell line;chicken

Proteomic Analysis Revealed Metabolic Inhibition and Elongation Factor Tu Deamidation by p-Coumaric Acid in Cronobacter sakazakii

Lu Ping,Ji Xuemeng,Xue Juan,Dong Yinping,Chen Xi

Screening drugs and compounds to fight against Cronobacter sakazakii (C. sakazakii), one of the most common pathogens that can cause fatal necrotizing enterocolitis, septicema and meningitis, is still needed. We found that p-coumaric acid (pCA) has an inhibitory effect on C. sakazakii in vitro and in vivo. Proteomic changes of C. sakazakii BAA-894 exposed to pCA were studied to reveal the antibacterial mechanisms involved. A total of 1,553 proteins were identified in C. sakazakii BAA-894 by label-free proteomics analysis. Fuzzy cluster analysis showed that 33 were up-regulated, and 110 were down-regulated with pCA treatment. Gene Ontology (GO) analysis concluded that pCA caused the change of metabolic state of bacteria and generally in the state of metabolic inhibition. KEGG Enrichment Analysis (KEGG) analysis showed that pCA inhibited energy metabolism and distorted the balance of amino acid metabolism. Posttranslational modification analysis showed that pCA affected the deamidation of three proteins, including Elongation factor Tu, one of the vital proteins in bacteria. Molecular docking suggested the hydrogen bond between the pCA carboxyl group and Elongation factor Tu Asn-64 might contribute to deamidation. Overall, we found that pCA interfered with cellular energy and amino acid metabolism and promoted elongation factor Tu deamidation, suggesting that pCA can be an effective natural substitute to control C. sakazakii.

Reversal of P-glycoprotein-mediated multidrug resistance by doxorubicin and quinine co-loaded liposomes in tumor cells

Qiying Shen,Liyan Qiu

Pyrolysis Behavior of Ester Substituted Poly(p-phenylene)s and Determination of Its Microstructural Arrangement through TGA

Danbo Mao,Yuechuan Wang

Abstract Four 2,5-dicholorobenzoate monomers were prepared by chlorination and esterification and then polymerized to ester substituted poly( p -phenylene)s through Ni/Zn catalyzed coupling reaction. The thermal stability and pyrolysis behavior of ester substituted poly( p -phenylene)s were investigated through TGA method. The possible mechanism of thermal modification of the polymers was proposed that included de-esterification, dehydration and decarboxylation, and finally de-anhydridization. Only pyrolysis of esters substituted poly( p -phenylene)s containing two neighboring carboxyl groups may result in the formation of the corresponding anhydride.

Fabrication of P(AN-MA)/rGO-g-PAO Superhydrophilic Nanofiber Membrane for Removal of Heavy Metal Ions

Wang Weijing,Han Na,Yang Chao,Zhang Wenxin,Miao Jinlei,Li Wei,Zhang Xingxiang

The process in which the nanofiber membrane is used to remove heavy metal ions and separation of oil-water solution is analyzed. Herein, smooth structures are induced by rGO-g-PAO sheets, which could be attributed to the strong interaction between P(AN-MA) and rGO-g-PAO. It is rewarding to note that the P(AN-MA)/rGO-g-PAO nanofiber membrane would exhibit superhydrophilic traits in the air and ultra-low oil-adhesive traits underwater when the concentration of P(AN-MA) and PAO is 13 wt.% and 0.3 wt.%, respectively. The amidoxime (–C(NH2) NOH) groups on the membrane surface can efficiently adsorb copper (Cu(II)) (1.65 mmol/g) and chromium (Cr(VI)) (4.70 mmol/g) ions in the waste water. Meanwhile, the P(AN-MA)/rGO-g-PAO nanofiber membrane exhibits ultrahigh flux (~6150 LMH), satisfying rejection rate (~97%) and outstanding flux recovery ratio (~99%) in separating oil water emulsion.

Achieving Balanced Electrical Performance of Host Material through Dual N–P═O Resonance Linkage for Efficient Electroluminescence

Huanhuan Li,Chang Liu,Xin Wang,Jiangchao Wang,Ping Li,Gaozhan Xie,Yunbo Jiang,Runfeng Chen,Ye Tao

Developing high-performance host materials is one of the biggest challenges for blue and white thermally activated delayed-fluorescence (TADF) organic light-emitting diode (OLED) technology due to the rigorous requirements of both efficient carrier flux ability and high triplet energy (ET) levels in static donor–acceptor molecules. Here, with the aid of a dual-resonance strategy, a host molecule showing dynamic adaption features in the acceptor–resonance–donor–resonance–acceptor (A–r–D–r–A) molecular configuration has been successfully developed through the implantation of two acceptors of diphenylphosphine oxide into electron-donating 5,10-dihydrophenazine with N–P═O resonance linkages. Owing to the dual enantiotropic N+═P–O– resonances, the designed A–r–D–r–A molecule exhibits an extraordinarily balanced charge flux transportation attribute at high ET (2.96 eV). Excitingly, blue and warm-white TADF OLEDs hosted by the A–r–D–r–A molecule exhibit outstanding external quantum efficiencies of 14.7 and 20.3%, respectively. Our studies not only broaden the scope of resonance molecules but also indicate that a resonance structure is an effective linkage to develop optoelectronic materials with dynamically adaptive properties.

Effects of cobalt content on mechanical and corrosion properties of electroless Ni-Co-P/TiN nanocomposite coatings

L.T. Shi,J. Hu,L. Fang,F. Wu,X. L. Liao,F. M. Meng

Ternary Ni-Co-P/TiN (20 nm) nanocomposite coatings with Co content in the range of 0–23 wt% were successfully co-deposited on Al alloys by electroless plating. The morphology, composition, microstructure, micro-hardness, wear behavior, and corrosion properties of the coatings were tested using SEM, EDS, XRD, Vickers hardness, ball-on-disc wear tester, and electrochemical workstation, respectively. The effect of Co content on the tribological and corrosion properties of Ni-Co-P/TiN coatings was studied. It is found that all the coatings have a compact and rough granular structure with sub-micro globules non-uniformly distributed on the surface. The grain size and the content of Ni and P decrease, but the micro-hardness, adhesion force, friction coefficient, and corrosion resistance correspondingly enhance with the increase of Co content in Ni-Co-P/TiN coatings. The improved corrosion resistance of Ni-Co-P/TiN coating is due to the passivation behavior and small grain caused by the introduction of Co. Based on the excellent properties on the wear and corrosion resistance, ternary Ni-Co23-P/TiN coating with high Co content, may be applied as an optimum protective coating for Al alloys.

Enhanced electrical conductivity of P-doped apatite-type lanthanum silicate solid electrolytes and analysis of the mechanism

Shang Haixin,Huang Zhiliang

Mono-doped lanthanum silicate solid electrolyte ceramics with phosphorus was successfully prepared by using the urea-nitrate combustion method at 600 °C. The crystal structure and morphology were analyzed by scanning electron microscope (SEM), infrared spectrometer (IR), and X-ray diffractometer (XRD), and the results showed that the successful doping of phosphorus into the lanthanum silicate electrolyte did not destroy the unique crystal structure of the space group P6 3 /m, and the best-sintered morphology of lanthanum silicate was achieved at 1500 °C. Meanwhile, the impedance test was conducted at 600 °C using electrochemical impedance spectroscopy (EIS), and the experimental data showed that with the increase of phosphorus doping, the conductivity of La 9.33 Si 6- x P x O 26+x/2 ( x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) first increased and then decreased. Also, at x = 0.4, the conductivity of the electrolyte reached a maximum of 7.27 mS/ cm (800 °C), which is because when phosphorus enters the Si site in the lanthanum silicate crystal structure, interstitial oxygen is generated in the 6 3 channel of the structure to maintain the electrovalent balance, and the increase in the concentration of interstitial oxygen increases the conductivity of the electrolyte. Therefore, an enhanced conductivity mechanism with defects in interstitial oxygen concentration is proposed.

Synthesis of a P/N/S-based flame retardant and its flame retardant effect on epoxy resin

Qianqian Zhang,Jun Wang,Shuang Yang,Jianwen Cheng,Guoping Ding,Yefa Hu,Siqi Huo

In order to meet the requirement in the fields with high flame resistance, the flame retardancy of epoxy resin (EP) must be ameliorated. Herein, a P/N/S-based flame retardant (PAD) was synthesized and used to prepare flame retardant EP. The combustion behavior, thermal property and flame retardant mechanism of the prepared EP thermosets were investigated. PAD induced the decomposition of EP thermoset in advance. Meanwhile, PAD enhanced the flame retardance of EP thermosets and reduced the fire risk of EP matrix. For example, with only 0.5 wt% phosphorus, EP/DDS/PAD-0.5 easily passed UL-94 V-0 rating and achieved a LOI value of 33.6%, together with the declined heat release rate (HRR). Impressively, the glass transition temperature (T g ) of EP/DDS/PAD thermosets dropped by only 3–13 °C, compared with that of EP/DDS. During combustion, PAD prompted the formation of an intumescent char layer in condensed phase, and exerted blowing-out effect in gaseous phase .

Volatile alcohol-responsive visual sensors based on P(HEMA-co-MA)-infiltrated SiO2 inverse opal photonic crystals

Jiaqi Liu,Yuqi Zhang,Ru Zhou,Loujun Gao

Functional molecule-infiltrated inverse opal photonic crystals can exhibit reversible photonic stopband shifts as a response to the external environment, which enables them to be promising chemical or biochemical sensors. The present study reports on a copolymer, poly(2-hydroxyethyl methacrylate-co-methyl acrylate), infiltrated SiO2 inverse opal as visual sensor for the detection of volatile alcohols vapors. The constructed sensor generates remarkable stopband red-shifts when exposed to an atmosphere of volatile alcohols. Particularly for isopropanol and butanol, a red-shift of more than 85 nm can be obtained and the color of the sensor changes from green to red, which can be observed by the naked eye. This can be attributed to the increased effective refractive index of the inverse opal caused by the diffusion and adsorption of alcohol molecules into the pores. This is based on a combination of a three-dimensional macroporous structure of the inverse opal and strong affinity of the copolymer to alcohols. The exposure to air can reactivate the sensor because of the volatilization and desorption of alcohols. The selectivity, sensitivity and the reusability of the sensor have been investigated by monitoring the reflectance spectra. The results demonstrate that the prepared sensor can be used as a promising candidate as visual sensors for detecting volatile alcohol vapors.