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991.
992.
Thermal and pH Dual Responsive Copolymer and Silver Nanoparticle Composite for Catalytic Application
Luqman Ali Shah Wulian Chen Mohammad Siddiq Jianhua Hu Angang Dong Dong Yang 《中国化学》2015,33(4):467-472
N‐Isopropylacrylamide and vinyl imidazole copolymer, P(NIPAM‐co‐VI), was synthesized by free radical emulsion polymerization. Then, the copolymer and silver nanoparticle composite, P(NIPAM‐co‐VI)‐Ag, was prepared by in situ reduction of AgNO3 with NaBH4. Due to the coexistence of thermal‐responsive PNIPAM and pH‐responsive PVI, P(NIPAM‐co‐VI) and P(NIPAM‐co‐VI)‐Ag exhibited both thermal and pH responsibility, their size would change while altering the temperature or pH of the circumvent. Their thermal and pH dual responsive properties were studied by dynamic light scattering (DLS). P(NIPAM‐co‐VI)‐Ag could be stably dispersed in water at a pH range from 3.0 to 9.3, which is favorable to use P(NIPAM‐co‐VI)‐Ag as a catalyst in the reduction reaction of p‐nitrophenol. The reaction rate constant (kapp) increased with the decrease of pH or the increase of VI content in the copolymer. 相似文献
993.
Sayyid Mahdi Rafigh Amir Heydarinasab 《International Journal of Polymer Analysis and Characterization》2017,22(6):497-508
In this study, hydroxyethyl curdlans (HeCDs) with different molecular weights were successfully fabricated. The structure and properties of the synthesized HeCDs were measured by FTIR, 13C nuclear magnetic resonance (NMR), and Raman spectroscopy and compared with curdlan. The degree of crystallinity of HeCDs was measured with X-ray diffractometry (XRD). Differential scanning calorimetry and thermogravimetric analysis were performed to determine thermal properties of HeCs. Solubility of HeCDs was tested in water, common organic solvents, and NaOH solution. Antioxidant activities of HeCs were investigated using various in vitro assay systems. The HeCDs exhibited a dose-dependent free radical scavenging activity as shown by their DPPH radical, ABTS radical and superoxide anion radical inhibition, and ferrous chelating ability and reducing power. The improved water solubility property and antioxidant activity of these curdlan derivatives could have a wide range of applications, particularly its use as an antioxidant in food, food packaging, biomedical, and pharmaceutical industries. 相似文献
994.
995.
Varish Ahmad Qazi Mohammad Sajid Jamal Arun K. Shukla Javed Alam Ahamad Imran Usama Mohamed Abaza 《Journal of Cluster Science》2017,28(4):1775-1802
The search of eco-friendly technologies for nano-synthesis is significant to expand their applications in human welfare. Nowadays, various inorganic nanoparticles with beneficial features have been synthesized via physical, chemical, and biological means. Significant biological applications of silver nanoparticles include on-infectious microbes, target drug delivery, cancer and vector-borne disease control. Their syntheses have been tested from plant fungi, bacteria, and viruses. The bacterial mediated synthesis of silver, gold, zinc and other metal leads to a milestone in nano-medicines. Thus, in this review, we focus on the contribution of Bacilli in the synthesis of silver nanoparticles, the mechanism of action and their potential application in the welfare of human beings. 相似文献
996.
JPC – Journal of Planar Chromatography – Modern TLC - A simple and robust thin-layer chromatography (TLC) method has been developed and validated for the simultaneous quantitative... 相似文献
997.
998.
Niyaz Ahmad Rizwan Ahmad Atta Abbas Naqvi Md Aftab Alam Mohammad Ashafaq Zeenat Iqbal 《液相色谱法及相关技术杂志》2017,40(3):133-146
The study reports a rapid and short analytical technique for separation, characterization, and quantitation along with comparative pharmacological effect of curcuminoids in cerebral ischemia. Flash chromatography, using silica and diol columns along with gradient mobile phase, was utilized to separate three curcuminoids, i.e., curcumin (Cur), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) for the first time. The separated peaks were monitored at 200–360?nm, whereas the purity of compounds (96.2–97.6%) was determined through qualitative analysis such as infrared and 1H and 13C-nuclear magnetic resonance spectroscopy, mass spectrometry (MS), and differential scanning calorimetry. Furthermore, chitosan nanoparticles (CS-NPs) for curcuminoids were prepared and characterized through zeta sizer, zeta potential, scanning electron microscopy, and transmission electron microscopy. The developed ultra performance of liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry/mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) method showed simplified automation and shorter run time for Combi flash over conventional separation techniques. The CS-NPs for all the three curcuminoids and combined-curcuminoids (CCr) (combined and administered together for a synergistic effect), following intranasal administration in middle cerebral artery–occluded rats were evaluated for grip strength, locomotor activity, and histopathological examination where the anti-ischemic activity was observed, in terms of potency, for all three CS-NPs and CCr as CCr>Cur>DMC>>BDMC. Cur-CS-NPs exhibited more potency among Cur, DMC, and BDMC, whereas CCr was the more potent anti-ischemic drug compared to Cur, DMC, and BDMC. For Cur the characteristic activity is proposed because of the presence of methoxy group on the phenyl ring whereas for CCr it is synergistic effect of curcuminoids. 相似文献
999.
Mohammad Hemmat Esfe Mousa Rejvani Rostam Karimpour Ali Akbar Abbasian Arani 《Journal of Thermal Analysis and Calorimetry》2017,128(3):1359-1371
In the present paper, the effects of temperature and volume fraction on thermal conductivity of SWCNT–Al2O3/EG hybrid nanofluid are investigated. Single-walled carbon nanotube with outer diameter of 1–2 nm and aluminum oxide nanoparticles with mean diameter of 20 nm with the ratio of 30 and 70%, respectively, were dispersed in the base fluid. The measurements were conducted on samples with volume fractions of 0.04, 0.08, 0.15, 0.3, 0.5, 0.8, 1.5 and 2.5. In order to investigate the effects of temperature on thermal conductivity of the nanofluid, this characteristic was measured in five different temperatures of 30, 35, 40, 45 and 50 °C. The results indicate that enhancement of nanoparticles’ thickness in low volume fractions and at any temperature causes a considerable increment in thermal conductivity of the nanofluid. In this study, the highest enhancement of thermal conductivity was 41.2% which was achieved at the temperature of 50 °C and volume fraction of 2.5%. Based on the experimental data, an experimental correlation and a neural network are presented and for thermal conductivity of the nanofluid in terms of volume fraction and temperature. Comparing outputs of the experimental correlation and the designed artificial neural network with experimental data, the maximum error values for the experimental correlation and the artificial neural network were, respectively, 2.6 and 1.94% which indicate the excellent accuracy of both methods in prediction of thermal conductivity. 相似文献
1000.
Nazish Parveen Mohammad Omaish Ansari Thi Hiep Han Moo Hwan Cho 《Journal of Solid State Electrochemistry》2017,21(1):57-68
This paper reports a simple methodology for the synthesis of a polyaniline/titanium oxide/graphene hybrid (Pani/TiO2/GN) using a simple methodology, and their application as a supercapacitor electrode material for energy storage. The Pani/TiO2/GN hybrid was prepared by a simple approach by simultaneous generation of Pani and TiO2 in situ from aniline and titanium iso-propoxide, respectively, in the presence of GN under ice bath conditions. The incorporation of GN improved the electrical conductivity of Pani and helped to decrease the charge transfer resistance, whereas TiO2 generation by an in situ method increased the surface area considerably and enhanced the capacitance of the Pani/TiO2/GN hybrid. TEM showed that Pani and TiO2 were well incorporated and coated on the GN successfully. The shift of the peaks in the FTIR spectrum and XRD pattern of the Pani/TiO2/GN hybrid compared to their pure counterparts suggested that TiO2 and Pani had been perfectly coated on the GN, and there was a strong interaction among Pani, GN, and TiO2 particles. The electrochemical performance of the as-prepared Pani/TiO2/GN hybrid electrode showed a high specific capacitance of 403.2 F g?1 at a current density of 2 A g?1 and excellent cycling stability for up to 1000 cycles. This suggested that the effective incorporation of GN and TiO2 into Pani and the high surface area could simultaneously increase the electrochemical capacitance and cyclic stability of the Pani/TiO2/GN hybrid, leading to superior electrochemical performance. 相似文献