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1.
Synthesis of Small‐Sized,Porous, and Low‐Toxic Magnetite Nanoparticles by Thin POSS Silica Coating 下载免费PDF全文
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.
D. Amutha Rani Y. Yamamoto S. Mohri M. Sivakumar Y. Tsujita H. Yoshimizu 《Journal of Polymer Science.Polymer Physics》2003,41(3):269-273
In this study, a novel stepwise extraction method has been examined. The guest molecules housed between the helices of the clathrate δ form of syndiotactic polystyrene can be removed completely with this method. A systematic study of the preparation of a solvent‐free mesophase (emptied clathrate) membrane, its helical and residual solvent contents, and its structural transformations has been performed. In this first attempt, an enhancement in the TTGG helical content has been observed in the extracted membrane, and a conceptual mechanism is proposed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 269–273, 2003 相似文献
3.
S. Mohri D. Amutha Rani Y. Yamamoto Y. Tsujita H. Yoshimizu 《Journal of Polymer Science.Polymer Physics》2004,42(2):238-245
Syndiotactic polystyrene (sPS) has various crystalline forms such as α, β, γ, and δ forms, and a mesophase depending on the preparation method. In this study, we focused on the mesophase with the molecular cavity of sPS, which is obtained by step‐wise extraction of the guest molecules from the sPS δ form. To prepare the mesophase containing different shapes and sizes of the cavity, two kinds of the sPS δ form membrane cast from either toluene or chloroform solution were first prepared and then the guest molecules were removed by a step‐wise extraction method using acetone and methanol. We could succeed in the preparation of two kinds of mesophase with different shapes and sizes of the molecular cavity. Either toluene or chloroform vapor sorption to the sPS mesophase membranes was examined at 25 °C. Sorption analysis indicates that the mesophase with large molecular cavities can mainly sorb large molecules; on the other hand, the mesophase with small cavities can sorb only the small molecules, and is unable to sorb a large amount of large molecule because the cavity was too small to sorb the large molecules. Therefore, the sPS mesophase membrane has sorption selectivity based on the size of the molecular cavity. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 238–245, 2004 相似文献
4.
Ai Suzuki Parasuraman Selvam Tomonori Kusagaya Seiichi Takami Momoji Kubo Akira Imamura Akira Miyamoto 《International journal of quantum chemistry》2005,102(3):318-327
The decomposition reaction dynamics of 2,3,4,4′,5‐penta‐chlorinated biphenyl (2,3,4,4′,5‐PeCB), 3,3′,4,4′,5‐penta‐chlorinated biphenyl (3,3′,4,4′,5‐PeCB), and 2,3,7,8‐tetra‐chlorinated dibenzo‐p‐dioxin (2,3,7,8‐TCDD) was clarified for the first time at atomic and electronic levels, using our novel tight‐binding quantum chemical molecular dynamics method with first‐principles parameterization. The calculation speed of our new method is over 5000 times faster than that of the conventional first‐principles molecular dynamics method. We confirmed that the structure, energy, and electronic states of the above molecules calculated by our new method are quantitatively consistent with those by first‐principles calculations. After the confirmation of our methodology, we investigated the decomposition reaction dynamics of the above molecules and the calculated dynamic behaviors indicate that the oxidation of the 2,3,4,4′,5‐PeCB, 3,3′,4,4′,5‐PeCB, and 2,3,7,8‐TCDD proceeds through an epoxide intermediate, which is in good agreement with the previous experimental reports and consistent with our static density functional theory calculations. These results proved that our new tight‐binding quantum chemical molecular dynamics method with first‐principles parameterization is an effective tool to clarify the chemical reaction dynamics at reaction temperatures. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献
5.
Analysis of rabbit tear proteins by high-pressure liquid chromatography/electrospray ionization mass spectrometry 总被引:4,自引:0,他引:4
Zhou L Beuerman RW Barathi A Tan D 《Rapid communications in mass spectrometry : RCM》2003,17(5):401-412
The aim of this study was to develop a fast and reliable analytical procedure for the display of the protein components of tears that can be used to differentiate the status of the ocular surface. Using this new procedure, we analyzed the tear protein components following a corneal wound in the rabbit. Calibrated 10-microL glass, fire-polished capillary micropipettes were used to collect tears from New Zealand White rabbits prior to and daily for 9 days following a unilateral 6-mm diameter centrally placed anterior keratectomy. Tear proteins were eluted by a reversed-phase high-performance liquid chromatography (RP-HPLC) column and the tear protein profile was monitored by electrospray ionization (ESI) mass spectrometry positive total ion current (TIC) chromatography. Tear proteins were reliably separated into 17 peaks, each of which contained one or a number of protein components. The molecular weight of each protein component was determined by on-line ESI. Major tear protein components, lactoferrin, lysozyme (minimally detectable in rabbit tears), albumin, lipocalin, lipophilin and beta2-microglobulin, were tentatively identified by this method. Based on the mass spectrometric data, beta2-microglobulin was found to be glycosylated with N-acetylhexosamine. ESI-positive TIC chromatograms and mass spectra revealed comparative differences in the tear protein spectra after corneal wounding. One day after wounding, rabbit lysozyme with a molecular weight of 14,717 Da was found to be 8-fold higher in the tears of wounded eyes when compared with tears from unwounded eyes. It dropped back to normal 3 days after wounding. The expression of an unidentified tear protein with the molecular weight of 16,060 Da was also elevated after corneal wounding and returned to normal level by day 5. In this study, LC/ESI-MS was developed as a fast, reproducible and simple method for the identification and analysis of many of the protein components of the tears. Importantly, this technique also allows quantification of each component resolved in the chromatogram. This method is very suitable for mapping peptides and proteins (<80 kDa) in tears. 相似文献
6.
Pal M Batchu VR Parasuraman K Yeleswarapu KR 《The Journal of organic chemistry》2003,68(17):6806-6809
We herein report the efficient syntheses of 4-(hetero)aryl-substituted 1-chlorophthalazines via heteroarylation of arenes/heteroarenes through AlCl(3)-induced C[bond]C formation reactions. A number of (hetero)arenes were reacted with 1,4-dichlorophthalazine to give aryl/heteroaryl-substituted phthalazines in good to excellent yields. Many of them were converted to the corresponding phthalazin-1(2H)-ones. 相似文献
7.
M. Amutha G. Ramasamy S. P. Meenakshisundaram S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2011,104(3):949-954
The influence of the s-, p-, d-, and f-block elements (Cs, Sb, Pd, and Ce) doping on the properties of ammonium dihydrogen
phosphate (ADP) crystals has been described. Incorporation of small quantity of dopants into the crystalline matrix is well
confirmed by energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma (ICP) techniques. The reduction in
the intensity observed in powder X-ray diffraction (XRD) of doped specimens and slight shifts in vibrational frequencies confirm
the lattice stress. Surface morphological changes due to doping of metals are observed by scanning electron microscopy (SEM).
The differential scanning calorimetry (DSC) curves show only a slight variation in endothermic peak temperatures. The sharpness
of the DSC peaks shows the good degree of crystallinity of the material. The cell parameters have been determined using single
crystal XRD analysis of pure ADP and ADP:Cs/ADP:Sb/ADP:Pd/ADP:Ce specimens. The influence of metals on the second harmonic
generation (SHG) efficiency is also investigated. 相似文献
8.
M. Ingarsal P. Amutha M. Gopalakrishnan S. Nagarajan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):515-522
Abstract The 4,6-diaryl-6,7-dihydro-[1,2,3]selenadiazolo[5,4-c]pyridine-5(4H)-carbalde hydes were synthesized from 2,6-diarylpiperidin-4-ones and characterized using infrared, 1H, 13C Nuclear Magnetic Resonance (NMR), and mass spectroscopic techniques. On the NMR time scale, the compounds exist in syn and anti isomeric forms. Separate signals were obtained for isomers in the NMR spectra. The compounds’ stereodynamic nature was studied based on the intensity and position of NMR signals. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
9.
Enzyme from Daucus carota root catalyzed Henry reaction of substituted benzaldehydes and nitromethane in phosphate buffer of pH 7 at 28?°C to afford β-nitroalcohols in excellent yields (up to 94%). 相似文献
10.
Dey S Pal C Nandi D Giri VS Zaidlewicz M Krzeminski M Smentek L Hess BA Gawronski J Kwit M Babu NJ Nangia A Jaisankar P 《Organic letters》2008,10(7):1373-1376
3,3'-Bipyrroles 3 could be synthesized using a double Michael addition reaction involving diaroyl acetylene 1 and the appropriate 1,3-dicarbonyls 2 using ammonium acetate as a nitrogen source. The axial chirality of bipyrrole was anticipated from the X-ray crystal structure and DFT calculations and confirmed by separating the racemates on a chiral column and subsequent CD spectra of the enantiomers. The absolute configuration of the enantiomers was achieved by theoretical CD spectra calculation using the ZINDO method. 相似文献