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排序方式: 共有103条查询结果,搜索用时 15 毫秒
61.
Wlodzimierz M. Daniewski Andrzej Wawrzun Maria De Bernardi Giovanni Vidari Paola Vita-Finzi Giovanni Fronza Giuseppina Gatti 《Tetrahedron》1984,40(14):2757-2762
The structures of lactarorufins D and E, two new sesquiterpenes from Lactarius necator, have been elucidated. Conformational analysis of lactarorufins and blennins is discussed. 相似文献
62.
Anthracyclines belong to the anticancer drugs that are widely used in chemotherapy. However, due to their systemic toxicity they also exert dangerous side effects associated mainly with cardiovascular risks. The pathway that is currently often developed is their chemical and physical modification via formation of conjugated or complexed prodrug systems with a variety of nanocarriers that can selectively release the active species in cancer cells. In this study, six new nanoconjugates were synthesized with the use of polyhedral oligosilsesquioxanes [POSS(OH)32] as nanocarriers of the anticancer drugs anthracyclines—doxorubicin (DOX) and daunorubicin (DAU). These prodrug conjugates are also equipped with poly(ethylene glycol) (PEG) moieties of different structure and molecular weight. Water-soluble POSS, succinic anhydride modified (SAMDOX and SAMDAU) with carboxylic function, and PEGs (PEG1, PEG2 and PEGB3) were used for the synthesis. New nanoconjugates were formed via ester bonds and their structure was confirmed by NMR spectroscopy (1H-NMR, 13C-NMR, 1H-13C HSQC, DOSY and 1H-1H COSY), FTIR and DLS. Drug release rate was evaluated using UV-Vis spectroscopy at pH of 5.5. Release profiles of anthracyclines from conjugates 4–9 point to a range of 10 to 75% (after 42 h). Additionally, model NMR tests as well as diffusion ordered spectroscopy (DOSY) confirmed formation of the relevant prodrugs. The POSS-anthracycline conjugates exhibited prolonged active drug release time that can lead to the possibility of lowering administered doses and thus giving them high potential in chemotherapy. Drug release from conjugate 7 after 42 h was approx. 10%, 33% for conjugate 4, 47% for conjugate 5, 6, 8 and 75% for conjugate 9. 相似文献
63.
1H, 1H–1H COSY and 13C NMR techniques were proven as effective methods for the analysis of functionalized doxorubicin (DOX) and daunorubicin (DAU) derivatives. These compounds represent important drug conjugate intermediates that can be coupled to a variety of nanocarriers. NMR spectroscopy was shown to be an efficient method for following the progress of drug modification and can also be useful for evaluation of the functionalized structures purity. Additionally, a correction of the chemical shifts reported in the literature for the relevant drugs e.g. DOX·HCl and DAU·HCl is presented. 相似文献
64.
Optimum sample medium for single-nucleotide polymorphism and mutation detection by capillary electrophoresis 总被引:2,自引:0,他引:2
Capillary electrophoresis (CE) is a versatile analytical platform widely used for nucleic acids analysis. Its applications in research and diagnostics include scanning and screening for mutations and polymorphisms by such reliable methods as single-strand conformation polymorphism (SSCP), heteroduplex analysis (HA), and combined SSCP/HA. This study, aimed at the further development of these methods, is focused on detailed sample-media characteristics. Factors affecting single-strand conformer stability and DNA intake efficiency were analyzed. The sample media optimal for efficient mutation or SNP detection were determined, and complex SSCP-CE patterns arising from unpurified PCR products were explained. It turns out, that the nondenaturing aqueous media assure both efficient DNA intake, and single-strand conformers stability required for the SSCP and combined SSCP/HA. The results of this study are applicable to all these areas of biomedical research, in which capillary electrophoresis is used for the characterization of nucleic acids. 相似文献
65.
Wlodzimierz Bak Andrzej Hulanicki 《Proceedings of the American Mathematical Society》2006,134(5):1467-1472
We prove that the spectrum of a convolution operator on a locally compact group by a self-adjoint -function is the same on and and consequently on all spaces, if and only if a Beurling algebra contains non-analytic functions on operating on into .
66.
The paper gives new examples of A-structures on certain SO(3)-principalfibre bundles. 相似文献
67.
Wlodzimierz Bryc Wojciech Matysiak Jacek Wesolowski 《Transactions of the American Mathematical Society》2007,359(11):5449-5483
We introduce the quadratic harness condition and show that integrable quadratic harnesses have orthogonal martingale polynomials with a three step recurrence that satisfies a -commutation relation. This implies that quadratic harnesses are essentially determined uniquely by five numerical constants. Explicit recurrences for the orthogonal martingale polynomials are derived in several cases of interest.
68.
Piyush S. Sharma Marcin Dabrowski Krzysztof Noworyta Tan-Phat Huynh Chandra B. KC Janusz W. Sobczak Piotr Pieta Francis D’Souza Wlodzimierz Kutner 《Analytica chimica acta》2014
For molecular imprinting of oxidatively electroactive analytes by electropolymerization, we used herein reductively electroactive functional monomers. As a proof of concept, we applied C60 fullerene adducts as such for the first time. For that, we derivatized C60 to bear either an uracil or an amide, or a carboxy addend for recognition of the adenosine-5′-triphosphate (ATP) oxidizable analyte with the ATP-templated molecularly imprinted polymer (MIP-ATP). Accordingly, the ATP complex with all of the functional monomers formed in solution was potentiodynamically electropolymerized to deposit an MIP-ATP film either on an Au electrode of the quartz crystal resonator or on a Pt disk electrode for the piezoelectric microgravimetry (PM) or capacitive impedimetry (CI) determination of ATP, respectively, under the flow-injection analysis (FIA) conditions. The apparent imprinting factor for ATP was ∼4.0. After extraction of the ATP template, analytical performance of the resulting chemosensors, including detectability, sensitivity, and selectivity, was characterized. The limit of detection was 0.3 and 0.03 mM ATP for the PM and CI chemosensor, respectively. The MIP-ATP film discriminated structural analogues of ATP quite well. The Langmuir, Freundlich, and Langmuir–Freundlich isotherms were fitted to the experimental data of the ATP sorption and sorption stability constants appeared to be nearly independent of the adopted sorption model. 相似文献
69.
Eva Chmielewská Wlodzimierz Tylus Marcela Morvová 《Central European Journal of Chemistry》2006,4(1):1-12
The paper deals with fabrication of carbonized and hydrophobized clinoptilolite-rich tuff using organic carbon rich substances,
here particularly starch and waste vegetable residues, which were pyrolytically combusted and covered the external zeolite
surface. Hydrophobization of the zeolite external surface was accomplished by octadecylammonium surfactant. Both surface modified
clinoptilolite-rich tuffs were tested and compared with each other with regard to removal of organic (phenol) and inorganic
(chromate, arsenate) pollutants from aqueous solutions. These elaborated composites with surface adsorbed pollutant species
were analysed by X-ray photoelectron spectroscopy (XPS). 相似文献
70.
We introduce the notion of a discrepancy function, as an extended real-valued function that assigns to a pair (A,U) of sets a nonnegative extended real number ω(A,U), satisfying specific properties. The pairs (A,U) are certain pairs of sets such that A⊆U, and for fixed A, the function ω takes on arbitrarily small nonnegative values as U varies. We present natural examples of discrepancy functions and show how they can be used to define traditional pseudo-metrics, quasimetrics and metrics on hyperspaces of topological spaces and measure spaces. 相似文献