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1.
Synthesis of Small‐Sized,Porous, and Low‐Toxic Magnetite Nanoparticles by Thin POSS Silica Coating
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Dr. Swee Kuan Yen D. Prathyusha Varma Wei Mei Guo Dr. Vincent H. B. Ho Dr. Vimalan Vijayaragavan Dr. Parasuraman Padmanabhan Prof. Kishore Bhakoo Prof. Subramanian Tamil Selvan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(10):3914-3918
In this communication, we report the synthesis of small‐sized (<10 nm), water‐soluble, magnetic nanoparticles (MNPs) coated with polyhedral oligomeric silsesquioxanes (POSS), which contain either polyethylene glycol (PEG) or octa(tetramethylammonium) (OctaTMA) as functional groups. The POSS‐coated MNPs exhibit superparamagnetic behavior with saturation magnetic moments (51–53 emu g?1) comparable to silica‐coated MNPs. They also provide good colloidal stability at different pH and salt concentrations, and low cytotoxicity to MCF‐7 human breast epithelial cells. The relaxivity data and magnetic resonance (MR) phantom images demonstrate the potential application of these MNPs in bioimaging. 相似文献
2.
Selvan Ravindran Sudipta Basu Santosh Kapil Kumar Gorti Prashant Surve Navya Sloka 《Biomedical chromatography : BMC》2013,27(5):575-582
The sulfonylurea urea drug glyburide (glibenclamide) is widely used for the treatment of diabetes milletus and gestational diabetes. In previous studies monohydroxylated metabolites were identified and characterized for glyburide in different species, but the metabolite owing to the loss of cyclohexyl ring was identified only in mouse. Glyburide upon incubation with hepatic microsomes resulted in 10 metabolites for human. The current study identifies new metabolites of glyburide along with the hydroxylated metabolites that were reported earlier. The newly identified drug metabolites are dihydroxylated metabolites, a metabolite owing to the loss of cyclohexyl ring and one owing to hydroxylation with dehydrogenation. Among the 10 identified metabolites, there were six monohydroxylated metabolites, one dihydroxylated metabolite, two metabolites owing to hydroxylation and dehydrogenation, and one metabolite owing to the loss of cyclohexyl ring. New metabolites of glyburide were identified and characterized using liquid chromatography–diode array detector–quadruple‐ion trap–mass spectrometry/mass spectrometry (LC‐DAD‐Q‐TRAP‐MS/MS). An enhanced mass scan–enhanced product ion scan with information‐dependent acquisition mode in a Q‐TRAP‐MS/MS system was used to characterize the metabolites. Liquid chromatography with diode array detection was used as a complimentary technique to confirm and identify the metabolites. Metabolites formed in higher amounts were detected in both diode array detection and mass spectrometry detection. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
3.
Suchismita Guha Matti Knaapila Dhanashree Moghe Zuzana Konôpková Mika Torkkeli Martin Fritsch Ullrich Scherf 《Journal of Polymer Science.Polymer Physics》2014,52(15):1014-1023
The role of high pressure on a low molecular weight nematic liquid crystalline organic semiconductor, ethyl‐hexyl substituted polyfluorene (PF2/6) is investigated using photoluminescence (PL), Raman scattering, and X‐ray scattering studies at pressures from 1 to 8 GPa. The PL and the Raman data under pressure are consistent with each other with no abrupt changes in the pressure coefficients of PL or Raman peaks. The PL energies redshift and broaden, consistent with both enhanced intra‐ and interchain interactions. The Raman peak positions yield pressure coefficients similar to other phenyl based π‐conjugated polymers. The broadening of a doublet peak in the 1135 cm?1 region indicates a more planar backbone conformation with increasing pressure. X‐ray scattering indicates that the torsion angle between adjacent repeats reduces with increasing pressure and reverts back with decompression. The intermolecular structure is weakly ordered (frozen nematic) and essentially maintained with increasing pressure, in contrast to a high molecular weight PF2/6. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1014–1023 相似文献
4.
New metal-carbon clusters, M4C9
+ (M = Ti, V), generated using a combined thermal arc discharge evaporation set-up, have been studied with quadrupole mass
spectrometry. Reactivities of these clusters have been investigated by means of association reactions with H2O. Metal-carbon clusters of other compositions have also been studied. We speculate on the mechanism of formation of larger
metal-carbon clusters. 相似文献
5.
Nanocrystalline CuFe2O4 and CuFe2O4/xSnO2 nanocomposites (x=0, 1, 5 wt%) have been successfully synthesized by one-pot reaction of urea-nitrate combustion method. The transmission electron microscope study reveals that the particle size of the as synthesized CuFe2O4 and CuFe2O4/5 wt%SnO2 are 10 and 20 nm, respectively. The SnO2 coating on the nanocrystalline CuFe2O4 was confirmed from HRTEM studies. The resultant products were sintered at 1100 °C and characterized by XRD and SQUID for compound formation and magnetic studies, respectively. The X-ray diffraction pattern shows the well-defined sharp peak that confirms the phase pure compound formation of tetragonal CuFe2O4. The zero field cooled (ZFC) and field cooled (FC) magnetization was performed using SQUID magnetometer from 2 to 350 K and the magnetic hysteresis measurement was carried out to study the magnetic properties of nanocomposites. 相似文献
6.
The MgO (2 0 0) surface is widely used as a substrate for epitaxial growth of superconducting and ferro-electric films. Highly oriented, single crystalline, extremely flat and transparent MgO films have been successfully deposited on quartz substrates by the chemical spray pyrolysis technique using economically viable metal organic and inorganic precursors under optimized conditions at the substrate temperature of 600 °C. Thermal analysis (TGA/DTA) in the temperature range 30-600 °C with the heating rate of 10 °C/min revealed the decomposition behavior of the precursors and confirmed the suitable substrate temperature range for film processing. The heat of reaction, ΔH due to decomposition of metal organic precursor contributed additional heat energy to the substrate for better crystallization. The intensity of the (2 0 0) peak in X-ray diffraction (XRD) measurements and the smooth surface profiles revealed the dependency of precursor on film formation. The compositional purity and the metal-oxide bond formation were tested for all the films. UV-Vis-NIR optical absorption in the 200-1500 nm range revealed an optical transmittance above 80% and the absorption edge at about 238 nm corresponding to an optical band gap Eg = 5.25 eV. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) micrographs of MgO films confirmed better crystallinity with larger grain size (0.85 μm) and reduced surface roughness (26 nm), respectively. 相似文献
7.
S. Sathiyaraj Mahalingam Vanjinathan G. Libni K. Subalakshmi J. Senthil Selvan 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(12):978-985
Hyperbranched poly(aryl-ether-urea)s with phenyl, N,N-dimethylamino ethyl and polyethylene oxide end-groups linked through urethane group – HBPEU-1, HBPEU-2 and HBPEU-3 respectively – were synthesized from an AB2-type blocked isocyanate monomer and characterized by FT-IR, 1H-NMR, SEC-MALLS, TGA and DSC techniques. The molecular weight of the polymers were found to be ranged from 4.9 × 103 ? 1.96 × 104 g/mol. The TGA results showed that the polymers decompose between 175°C – 220°C. In the DSC curves, HBPEU-1 and HBPEU-3 showed Tg at 160°C and 53°C respectively, whereas HBPEU-2 did not showed clear Tg. All the three polymers were converted into polymer electrolytes by doping with LiI/I2. The doped polymers showed remarkably high ionic conductivity, up to 222 – 277 times compared to the un-doped polymers and the highest conductivity was observed with doped HBPEU-2. The TiO2 based dye-sensitized solar cells (DSSCs) were fabricated using the doped polymer electrolytes and their performance was tested; HBPEU-2 showed good performance by yielding energy conversion efficiency (η) of 4.5%. 相似文献
8.
S. Sharmila B. Senthilkumar V.D. Nithya Kumaran Vediappan Chang Woo Lee R. Kalai Selvan 《Journal of Physics and Chemistry of Solids》2013
Submicron-sized polyhedral Li4Ti5−xSnxO12 (x=0.0, 0.05, and 0.1) materials were successfully prepared by a single-step molten salt method. The structural, morphological, transport and electrochemical properties of the Li4Ti5−xSnxO12 were studied. X-ray diffraction patterns showed the formation of a cubic structure with a lattice constant of 8.31 Å, and the addition of dopants follows Vegard's law. Furthermore, FT-IR spectra revealed symmetric stretching vibrations of octahedral groups of MO6 lattice in Li4Ti5O12. The formation of polyhedral submicron Li4Ti5−xSnxO12 particles was inferred from FE-SEM images, and a particle size reduction was observed for Sn-doped Li4Ti5O12. The chemical composition of Ti, O and Sn was verified by EDAX. The DC electrical conductivity was found to increase with increasing temperature, and a maximum conductivity of 8.96×10−6 S cm−1 was observed at 200 °C for Li4Ti5O12. The galvanostatic charge–discharge behavior indicates that the Sn-doped Li4Ti5O12 could be used as an anode for Li-ion batteries due to its enhanced electrochemical properties. 相似文献
9.
Ezhil Raj AM Selvan G Ravidhas C Jayachandran M Sanjeeviraja C 《Journal of colloid and interface science》2008,328(2):396-401
MgIn(2)O(4), which has an inverse spinel structure, has been adopted as the transparent material in optoelectronic device fabrication due to its high optical transparency and electrical conductivity. Such a technologically important material was prepared by the spray pyrolysis technique. Precursors prepared for the cationic ratio Mg/In=0.5 were thermally sprayed onto glass substrates at 400 and 450 degrees C. We report herein the preparation and characterization of the films by X-ray diffraction (XRD), energy-dispersive absorption X-ray spectroscopy (EDAX), and atomic force microscopy (AFM). The XRD results showed the single phase formation of the material that revealed the presence of Mg(2+) and In(3+) in the inverse spinel-related structure. The FTIR and EDAX results further confirmed that the nanocrystalline films were mainly composed of magnesium, indium, and oxygen, in agreement with XRD analysis. We surmised from the AFM micrographs that the atoms have enough diffusion activation energy to occupy the correct site in the crystal lattice. For the 423-nm-thick magnesium indium oxide films grown at 400 degrees C, the electrical conductivity was 5.63x10(-6) Scm(-1) and the average optical transmittance was 63% in the visible range (400-700 nm). Similar MgIn(2)O(4) films deposited at 450 degrees C have a conductivity value of 1.5x10(-5) Scm(-1) and an average transmittance of 75%. Hall coefficient observations showed n-type electrical conductivity and high electron carrier concentration of 2.7x10(19) cm(-3). 相似文献
10.
Chellappan Shobana Basuvannan Rangasamy Subramani Surendran Ramakrishnan Kalai Selvan Mathan Ramesh 《Journal of Cluster Science》2018,29(2):267-279
Biosynthesis of silver nanoparticles has received considerable attention due to their cost-effective, eco-friendly and medicinal values. In this study, silver nanoparticles (Ag NPs) were synthesised using the aqueous leaf extracts of Piper nigrum. TEM images revealed that the particle is spherical with 20–50 nm in size. Furthermore, to evaluate the toxicity of synthesized Ag NPs, fish Labeo rohita were exposed to two different concentrations (2.5 µg/L as the treatment I and 5 µg/L as treatment II) for 35 days, and antioxidant parameters and histology of gill, liver and kidney were examined. A biphasic response in the activity of glutathione S-transferases (GST) was observed in gill and liver of fish. GST activity in the kidney of fish was significantly increased when compared to control group. Glutathione reductase (GR) activity in organs/tissue of fish were found to be increased while peroxidase (POD) activity was significantly decreased. Histopathological changes such as hyperplasia, proliferation of epithelial cells and fusion of lamellae were observed in both the concentrations. In liver, necrosis, nuclear degeneration and dilation of sinusoids were observed. Subsequently, the representative effects of POD activity were assessed based on the Box–Behnken Equation, 3-D contour plot and ANOVA analysis through response surface methodology analysis. 相似文献