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1.
Bahraminasab A. Tabei S. M. A. Masoudi A. A. Shahbazi F. Reza Rahimi Tabar M. 《Journal of statistical physics》2004,116(5-6):1521-1544
The joint probability distribution function (PDF) of the height and its gradients is derived for a zero tension d + 1-dimensional Kardar-Parisi-Zhang (KPZ) equation. It is proved that the height's PDF of zero tension KPZ equation shows lack of positivity after a finite time t c . The properties of zero tension KPZ equation and its differences with the case that it possess an infinitesimal surface tension is discussed. Also potential relation between the time scale t c and the singularity time scale t c.v→0 of the KPZ equation with an infinitesimal surface tension is investigated. 相似文献
2.
Rahimipour S Litichever-Coslovsky N Alaluf M Freeman D Ehrenberg B Weiner L Mazur Y Fridkin M Koch Y 《Photochemistry and photobiology》2005,81(2):250-258
A combination of light, oxygen and a photosensitizer is used to induce death of cancer cells by photodynamic therapy. In this study, we have synthesized several new methyl helianthrone derivatives and compared their phototoxicity with that of hypericin. In contrast to hypericin, methyl helianthrones are soluble in aqueous solutions and have a broad range of light absorbance, which allows the use of polychromatic light. Structural modifications of methyl helianthrone demonstrated that substitution of hydrogen atoms of methyl helianthrone at Positions 2 and 5 with Br atoms or methylation of its phenolic hydroxyls, significantly increases the corresponding singlet oxygen quantum yield and their phototoxicity toward alphaT3-1, M2R and LNCaP cells. The phototoxicity of some of these compounds was similar to that of hypericin. Methyl helianthrones, like hypericin, accumulated mainly in the perinuclear region as evident by confocal microscopy. Irradiation of cells pretreated with methyl helianthrone derivatives generates intracellular reactive oxygen species and lipid free radicals, as shown by a fluorescentic probe and electron paramagnetic resonance methods, respectively. The phototoxicity of these methyl helianthrones as well as their ability to oxidize membrane lipids were significantly decreased on addition of specific Type-II inhibitors, suggesting the involvement of singlet oxygen as the main oxidant. 相似文献
3.
Itamar Willner Mazzi Lion-Dagan Shai Rubin Johann Wonner Franz Effenberger Peter Bäuerle 《Photochemistry and photobiology》1994,59(4):491-496
Abstract α-Chymotrypsin exhibits photoswitchable activities in an organic solvent after covalent modification of the protein backbone with thiophenefulgide active ester (2). The thiophenefulgide-modified α-chymotrypsin exhibits reversible photoisomerizable properties between states (3)-E and (3)-C. The modified α-chymotrypsin, where nine lysine residues are substituted by thiophenefulgide units, retains 60% of the activity of the native enzyme. The activities of thiophenefulgide-modified α-chymotrypsin toward esterification of N -acetyl-L-phenylalanine (4) by ethanol in cyclohexane are controlled by the configuration of the attached photoisomerizable component and by prior bioimprinting of the protein backbone with the reaction substrate (4). The esterification of (4) in cyclohexane using bioimprinted (3)-C is two-fold faster than in the presence of (3)-E. In the presence of a nonbioimprinted enzyme, esterification of (4) by (3)-C is five-fold faster than with (3)-E. The activity of bioimprinted (3)-E toward esterification of (4) is 4.5-fold higher than that of nonbioimprinted (3)-E. Switchable cyclic esterification of (4) is accomplished by sequential photoisomerization of the thiophenefulgide-modified α-chymotrypsin between states (3)-C and (3)-E. 相似文献
4.
Shai Ben-David Saharon Shelah 《Proceedings of the American Mathematical Society》1996,124(9):2827-2837
We show that the transfer property for singular does not imply (even) the existence of a non-reflecting stationary subset of . The result assumes the consistency of ZFC with the existence of infinitely many supercompact cardinals. We employ a technique of ``resurrection of supercompactness'. Our forcing extension destroys the supercompactness of some cardinals; to show that in the extended model they still carry some of their compactness properties (such as reflection of stationary sets), we show that their supercompactness can be resurrected via a tame forcing extension.
5.
Flameless atomic absorption techniques were used to determine the lead and other atmospheric particulate in the city of Tehran. 640 samples were collected in 20 different stations around the city during four seasons in 1992. The radioactivity of the air samples was also measured by -ray spectrometry using high purity Ge/Li detectors, and a multichannel analyzer. The results were compared with previous measurements in the city of Tehran. 相似文献
6.
Radiotracer method was developed for measuring14CO2 content in cement-wood mixtures. The carbon dioxide used for the treatment was labeled with14C, a -emitting radioisotope, and samples were measured by -scintillation and liquid scintillation techniques. Test samples were prepared in the laboratory with various compositions and treated with labeled14CO2. The tracer was released from Ba14CO3 by lactic acid with total activity of 37 MBq. Selectivity of the technique allows to distinguish the carbon dioxide bound during the treatment and bound previously from the mbient air. Sensitivity of the method is higher than that of traditional methods and allowed determination of CO2 content in each component of the mixture. It is 63 ng. if measured by -scintillation detector and 1.6 ng, if measured by liquid scintillation. Accuracy of the method is 0.3%. 相似文献
7.
Polyphosphazenes form one of the most important and interesting classes of inorganic polymers having a backbone of alternating
phosphorus and nitrogen atoms with phosphorus atom bearing two organic side groups. The most important feature of these polymers
is the synthesis route which allows the side groups to be changed over a wide range to obtain a broad variety of products
with different properties from elastomers to glasses, water soluble to hydrophobic polymers, bioinert to bioactive materials,
and electrical insulators to conductors. In this paper, some novel applications of these polymers in biomedical materials
and advanced devices are reviewed. 相似文献
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