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排序方式: 共有57条查询结果,搜索用时 31 毫秒
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Balasubramaniam P. Dauer J.P. Loganathan C. 《Journal of Optimization Theory and Applications》2002,114(2):273-286
In this paper, we establish a set of sufficient conditions for the local controllability of functional integrodifferential equations in Banach space. The results are obtained by using the methods of analytic semigroups, fractional powers of operators, and a fixed-point argument. These results generalize previous results on bounded linear operators to unbounded linear operators in which the equation involves a nonlinear delay term. An application to a partial integrodifferential equation is given. 相似文献
24.
Loganathan D Rodriguez JH Morrison H 《Journal of the American Chemical Society》2003,125(19):5640-5641
Photoaquation in compounds II and III by direct excitation into a photoactive triplet excited state is reported. The location of the singlet to triplet transition in compound III is estimated by a combination of the action spectrum for photoaquation in the region between 520 and 600 nm and the phosphorescence spectrum at 77 K. The significant increment of the reactivity (10-fold) of the triplet states in II and III as compared to that in I is explained in terms of increasing sigma-donation from the phen ligands stabilizing the pentacoordinated rhodium intermediate formed by chloride expulsion. 相似文献
25.
Schadewaldt P Kamalanathan L Hammen HW Wendel U 《Rapid communications in mass spectrometry : RCM》2003,17(24):2833-2838
An established gas chromatography/mass spectrometry (GC/MS) method, devised for stable-isotope dilution analysis of plasma galactose, was developed to allow determination of erythrocyte (red blood cell, RBC) concentrations of galactose-1-phosphate and other primary metabolites relevant in galactosaemia. Galactose-1-phosphate was enzymatically converted to galactose, and the aldononitrile pentaacetate derivative was separated by gas chromatography and determined by mass spectrometry using chemical ionisation and selected ion monitoring of the [MH-60](+) ion. U-(13)C-Labelled standard was used for quantification. Comparative measurements were conducted using established fluorimetric and radiometric enzymatic methods. The GC/MS analysis for galactose-1-phosphate was linear (range examined 0-600 micromol/L(RBC), packed cells), of acceptable repeatability at low and high concentrations (within and between run CVs <15%), with a limit of quantification of 0.01 micromol/L(RBC). With samples from patients with classical galactosaemia there was a linear correlation with conventional enzymatic assays (r(2) > 0.927). In erythrocytes from post-absorptive patients under treatment, Q188R-heterozygous parents, and healthy subjects, galactose-1-phosphate concentrations (mean +/- SD) were found to be 142 +/- 38 (n = 41), 1.4 +/- 0.2 (n = 8), and 1.9 +/- 0.5 (n = 33) micromol/L(RBC), respectively. In comparison, free galactose concentrations were 3.8 +/- 1.7, 0.49 +/- 0.19, and 0.43 +/- 0.20 mol/L(RBC), respectively. The procedure allowed simultaneous galactitol analysis and proved to be useful to trace incorporation of (13)C-label into erythrocyte galactose metabolites in a D-[1-(13)C]galactose in vivo turnover study. 相似文献
26.
Balasubramanian?Ranjani Jayaprakasham?Kalaiyarasi Loganathan?Pavithra Thiyagarajan?Devasena Kannaiyan?PandianEmail author Subash?C.?B.?GopinathView authors OrcID profile 《Mikrochimica acta》2018,185(3):194
A sensing device was constructed for the amperometric determination of nitrite. It is based on the use of titanium dioxide (TiO2) nanotubes template with natural fibers and carrying hemin acting as the electron mediator. A glassy carbon electrode (GCE) was modified with the hemin/TNT nanocomposite. The electrochemical response to nitrite was characterized by impedance spectroscopy and cyclic voltammetry. An amperometric study, performed at a working potential of + 0.75 V (vs. Ag/AgCl), showed the sensor to enable determination of nitrite with a linear response in the 0.6 to 130 μM concentration range and with a 59 nM limit of detection. Corresponding studies by differential study voltammetry (Ep?=?0.75 V) exhibited a linear range from 0.6?×?10?6 to 7.3?×?10?5 M with a limit of detection of 84 nM. The sensing device was applied to the determination of nitrite in spiked tap and lake water samples. 相似文献
27.
Anitha S. Loganathan K. Pichumani M. 《Journal of Thermal Analysis and Calorimetry》2021,144(5):1783-1798
Journal of Thermal Analysis and Calorimetry - Numerical analysis is carried out on heat transfer performance of industrial-length double-tube heat exchanger, by using hybrid nanofluid as a coolant... 相似文献
28.
The kinetics of phase-transfer catalyzed radical polymerization of N-vinyl imidazole (NVI) using potassium peroxy disulfate (PDS) as water soluble initiator and tetraoctylammonium chloride (TOAC) as PTC has been investigated in ethyl acetate/water two phase system assisted by ultrasound irradiation at constant temperature 60 + 1 °C under nitrogen atmosphere. and. The rate of polymerization increases with an increase in concentrations of NVI, PTC and PDS. The order with respect to [NVI], [PTC], and [PDS] were found to be 1.01, 1.03 and 0.52 respectively. Based on the observed results a suitable mechanism has been proposed to account for the experimental observations followed by a discussion on its significance. 相似文献
29.
Loganathan R Ramakrishnan S Suresh E Riyasdeen A Akbarsha MA Palaniandavar M 《Inorganic chemistry》2012,51(10):5512-5532
A series of mononuclear mixed ligand copper(II) complexes [Cu(bba)(diimine)](ClO(4))(2)1-4, where bba is N,N-bis(benzimidazol-2-ylmethyl)amine and diimine is 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), 5,6-dimethyl-1,10-phenanthroline (5,6-dmp) (3), or dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (4), have been isolated and characterized by analytical and spectral methods. The coordination geometry around copper(II) in 2 is described as square pyramidal with the two benzimidazole nitrogen atoms of the primary ligand bba and the two nitrogen atoms of phen (2) co-ligand constituting the equatorial plane and the amine nitrogen atom of bba occupying the apical position. In contrast, the two benzimidazole nitrogen atoms and the amine nitrogen atom of bba ligand and one of the two nitrogen atoms of 5,6-dmp constitute the equatorial plane of the trigonal bipyramidal distorted square based pyramidal (TBDSBP) coordination geometry of 3 with the other nitrogen atom of 5,6-dmp occupying the apical position. The structures of 1-4 have been optimized by using the density functional theory (DFT) method at the B3LYP/6-31G(d,p) level. Absorption spectral titrations with Calf Thymus (CT) DNA reveal that the intrinsic DNA binding affinity of the complexes depends upon the diimine co-ligand, dpq (4) > 5,6-dmp (3) > phen (2) > bpy (1). The DNA binding affinity of 4 is higher than 2 revealing that the π-stacking interaction of the dpq ring in between the DNA base pairs with the two bzim moieties of the bba ligand stacked along the DNA surface is more intimate than that of phen. The complex 3 is bound to DNA more strongly than 1 and 2 through strong hydrophobic interaction of the methyl groups on 5,6-positions of the phen ring in the DNA grooves. The extent of the decrease in relative emission intensities of DNA-bound ethidium bromide (EB) upon adding the complexes parallels the trend in DNA binding affinities. The large enhancement in relative viscosity of DNA upon binding to 3 and 4 supports the DNA binding modes proposed. Interestingly, the 5,6-dmp complex 3 is selective in exhibiting a positive induced CD band (ICD) upon binding to DNA suggesting that it induces a B to A conformational change. In contrast, 2 and 4 show induced CD responses indicating their involvement in strong DNA binding. Interestingly, only the dpq complex 4, which displays the strongest DNA binding affinity and is efficient in cleaving DNA in the absence of an activator with a rate constant of 5.8 ± 0.1 h(-1), which is higher than the uncatalyzed rate of DNA cleavage. All the complexes exhibit oxidative DNA cleavage ability, which varies as 4 > 2 > 3 > 1 (ascorbic acid) and 3 > 2 > 4 > 1 (H(2)O(2)). Also, the complexes cleave the protein bovine serum albumin in the presence of H(2)O(2) as an activator with the cleavage ability varying in the order 3 > 4 > 2 > 1. The highest efficiency of 3 to cleave both DNA and protein in the presence of H(2)O(2) is consistent with its strong hydrophobic interaction with the biopolymers. The IC(50) values of 1-4 against cervical cancer cell lines (SiHa) are almost equal to that of cisplatin, indicating that they have the potential to act as effective anticancer drugs in a time-dependent manner. The morphological assessment data obtained by using acridine orange/ethidium bromide (AO/EB) and Hoechst 33258 staining reveal that 3 induces apoptosis much more effectively than the other complexes. Also, the alkaline single-cell gel electrophoresis study (comet assay) suggests that the same complex induces DNA fragmentation more efficiently than others. 相似文献
30.
Ramu Rajasekaran Prakash Rao Aruna Dornadula Koteeswaran Loganathan Padmanabhan Kulandaivel Muthuvelu Ram Rathan Rai Palraj Thamilkumar Chilakapati Murali Krishna Singaravelu Ganesan 《Photochemistry and photobiology》2013,89(2):483-491
Urine is one of the diagnostically important bio fluids, as it has different metabolites in it, where many of them are native fluorophores. Native fluorescence characteristics of human urine samples were studied using excitation–emission matrices (EEMs) over a range of excitation and emission wavelengths, and emission spectra at 405 nm excitation, to discriminate patients with cancer from the normal subjects. The fluorescence spectra of urine samples of cancer patients exhibit considerable spectral differences in both EEMs and emission spectra with respect to normal subjects. Different ratios were calculated using the fluorescence intensity values of the emission spectra and they were used as input variables for a multiple linear discriminant analysis across different groups. The discriminant analysis classifies 94.7% of the original grouped cases and 94.1% of the cross‐validated grouped cases correctly. Based on the fluorescence emission characteristics of urine and statistical analysis, it may be concluded that the fluorophores nicotinamide adenine dinucleotide (NADH) and flavins may be considered as metabolomic markers of cancer. 相似文献