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51.
Youssef Masmoudi Habib Chabchoub Saïd Hanafi Ahmed Rebaï 《Journal of Mathematical Modelling and Algorithms》2010,9(3):247-255
In this paper we propose a new procedure for classification based on a hybrid approach. The classification problem is solved
by minimizing the distance between the components of each clusters and the centers of the clusters. The determination of the
cluster centers is therefore a critical step in our approach and was addressed used the k-means algorithm. Once the centers
of each class are determined, the rule of center neighbourhood is applied to assign an element to a class using mathematical
programming. The implementation of our hybrid approach was validated on benchmark datasets and applied to an original biological
dataset on 84 breast cancer tumours. Each tumour was measured for five parameters corresponding to the expression of five
biomarkers (proteins). The obtained classification was discussed using biological knowledge and classical clinical experts’
classification of breast tumors. 相似文献
52.
J.C. Sczancoski L.S. Cavalcante T. Badapanda S.K. Rout S. Panigrahi V.R. Mastelaro J.A. Varela M. Siu Li E. Longo 《Solid State Sciences》2010,12(7):1160-1167
[Ba1–xY2x/3](Zr0.25Ti0.75)O3 powders with different yttrium concentrations (x = 0, 0.025 and 0.05) were prepared by solid state reaction. These powders were analyzed by X-ray diffraction (XRD), Fourier transform Raman scattering (FT-RS), Fourier transform infrared (FT-IR) and X-ray absorption near-edge (XANES) spectroscopies. The optical properties were investigated by means of ultraviolet–visible (UV–vis) absorption spectroscopy and photoluminescence (PL) measurements. Even with the addition of yttrium, the XRD patterns revealed that all powders crystallize in a perovskite-type cubic structure. FT-RS and FT-IR spectra indicated that the presence of [YO6] clusters is able to change the interaction forces between the O–Ti–O and O–Zr–O bonds. XANES spectra were used to obtain information on the off-center Ti displacements or distortion effects on the [TiO6] clusters. The different optical band gap values estimated from UV–vis spectra suggested the existence of intermediary energy levels (shallow or deep holes) within the band gap. The PL measurements carried out with a 350 nm wavelength at room temperature showed that all powders present typical broad band emissions in the blue region. 相似文献
53.
54.
55.
Synthesis,plasma clearance,and in vitro stability of protein containing a conjugated indium-111 chelate 总被引:1,自引:0,他引:1
C. H. Paik D. E. Herman W. C. Eckelman R. C. Reba 《Journal of Radioanalytical and Nuclear Chemistry》1980,57(2):553-564
A new bifunctional chelating agent, N′-(p-diazoniumbenzyl)-N,N N″,N″-diethylenetri-aminetetraacetic acid (DTTA) was synthesized.
The compound as coupled to methyl p-hydroxybenzimidate and the resulting azoimidate was attached to lysine residues of monomeric
human serum albumin (HSA) via the amidination reaction. Blood clearnace of111In-labelled DTTA conjugated to HSA (AAHSA) in rabbits was biphasic. The first phase has a clearance indistinguishable from
that of125I-labeled HSA. During the second phase, the111In-labeled AAHSA was cleared more rapidly so that between 24 hours and 48 hours the percent of the injected dose of111In-labeled AAHSA in the blood was significantly lower than that of125I-labeled HSA. Highly conjugated111In-labeled AAHSA (0.9 DTTA/HSA) showed accelerated clearance at 24 and 48 hours compared to lightly conjugated protein (<0.9
DTTA/HSA). As a result we postulate that the level of conjugation is the critical parameter controlling the blood clearance. 相似文献
56.
Oxidation of sulfanilic acid to the corresponding azoxy derivative by peroxomonophosphoric acid (PMPA) has been studied in aqueous medium. The observed bell-shaped pH-rate profile has been rationalized on the basis of protonation of the amino group and ionization into different PMPA species and a suitable rate law has been proposed. The mechanism of oxidation involves the nucleophilic attack of nitrogen on the electrophilic peroxo oxygen.
- (PMPA) . pH— , PMPA . .相似文献
57.
C. H. Paik F. Vieras W. C. Eckelman R. C. Reba 《Journal of Radioanalytical and Nuclear Chemistry》1980,60(1):281-289
99mTc-labeled transferrin was prepared by reduction of99mTcO
4
−
; with stannous DTPA or stannous citrate followed by equilibration of the technetium chelate with human transferrin. The rate
of transfer of99mTc to transferrin in the presence of 0.015M citrate buffer was dependent on pH in the order pH 2.1> pH 7.2> pH 4.1> pH 5.9.
The incorporation rate was inversely proportional to the concentration of DTPA and citrate buffer. The replacement of citrate
buffer by acetate buffer or oxalate buffer reduced drastically the formation of99mTc-labeled transferrin at pH 4.1. The formation of99mTc-labeled transferrin prepared from the reduction of99mTcO
4
−
with stannous citrate was faster than that from the reduction with stannous DTPA in the presence of 0.015M citrate buffer
and pH 2.5. Equilibration of transferrin with99mTc-labeled pyrophosphate did not produce99mTc-labeled transferrin at pH 4.5. The ligand exchange labeling of99mTc to transferrin in 0.015M citrate did not cause appreciable denaturation of the protein at all pH values. This method also
enabled labeling of the protein in a low concentration (2.6·10−4 M) via tin reduction. Sequential external imaging of the99mTc-labeled transferrin in Sprague-Dawley rats bearing Walker-256 carcinosarcoma showed optimal tumor localization occurred
at 3 hr after injection. In spite of this,99mTc-labeled transferrin does not appear to be a suitable imaging agent because of the low tumor to blood ratio of99mTc (0.50±0.17) at 3 hr post injection. This is similar to that of6 7Ga-citrate (0.43±0.15%). 相似文献
58.
Pratima Panigrahi 《Geometriae Dedicata》1999,78(2):121-141
The root system E
8 has 120 diameters (i.e., lines joining pairs of opposite roots) any two of which make an angle of sixty or ninety degrees. The graph of the title has these diameters as its vertices, where two vertices are adjacent if and only if the corresponding diameters are at right angles. Known results in the literature imply that this graph is geometrisable. In this paper we prove that, modulo automorphisms of the graph, there is a unique way to construct this geometry out of the given graph. Along the way, we observe that this graph is locally the orthogonal graph O(7, 2). We also prove that, modulo automorphisms of the polar space, there is a unique spread of O(7,2). 相似文献
59.
The kinetics of electron transfer reactions between acetophenones with Ce(IV) have been studied in aqueous acetic acid medium in the presence of cationic micelle Cetylpyridinium chloride (CPyCl) at different temperatures. Kinetic data reveal first-order dependence with respect to each of Ce(IV) and acetophenones. The cationic micelle, Cetylpyridinium chloride enhances the oxidation reactions. The catalysis fits to a model developed by Menger and Portnoy as well as Berezin's phase separation model. The binding and partition constants and the transfer free energy from water to micelle have been estimated and discussed, suggesting that the solubilization of both the reactants in the micellar phase, facilitates the oxidation. © 1993 John Wiley & Sons, Inc. 相似文献
60.
Subrata?Kundu Anjali?Pal Sujit?Kumar?Ghosh Sudip?Nath Sudipa?Panigrahi Snigdhamayee?Praharaj Soumen?Basu Tarasankar?PalEmail author 《Journal of nanoparticle research》2005,7(6):641-650
Chelating ligands with β-diketone skeleton have been employed for the first time as reductant to produce ligand stabilized
gold nanoparticles of different shapes out of aqueous HAuCl4 solutions. Evolution of stable gold nanoparticles happens to be first order with respect to gold particles having rate constants
∼
∼10−2 min−1 and subsequent chlorine insertion in the β-diketone skeleton is reported as a general feature. Spherical or triangular or
hexagonal particle evolution goes selectively under the influence of different β-diketones in terms of capping and reducing
capabilities of the reductants. 相似文献