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Simultaneous analysis of diazepam and its metabolites in rat plasma and brain tissue by HPLC-UV and SPE 总被引:1,自引:0,他引:1
Laura Mercolini Carmelina Iannello Ferdinando Nicoletti Maria Augusta Raggi 《Talanta》2009,80(1):279-2918
Diazepam is frequently used as an adjuvant during antidepressant therapy. Recently, some studies have suggested that the treatment with benzodiazepines could have different efficacy in depressed patients as opposed to non-depressed ones. To clarify the matter, a study is currently underway, regarding the drug metabolism in rats. In order to obtain a more complete and significant set of data, the main diazepam metabolites have also been considered, namely: nordiazepam, temazepam and oxazepam. A feasible and reliable HPLC method has been developed for the simultaneous determination of these compounds in plasma and brain tissue of rats. The method has been applied to “normal” rats and to genetic rat models of depression in order to estimate drug metabolism in different breeds. Analyte separation was achieved on a C8 reversed phase column using an acidic phosphate buffer/acetonitrile mixture as the mobile phase. The detection wavelength was 238 nm. An original sample pre-treatment, based on solid-phase extraction (SPE) was developed in order to eliminate endogenous interference, using only 250 μL of matrix (brain homogenate or plasma) for a complete analysis. The method has been validated with good results in terms of precision, extraction yield, sensitivity, selectivity and accuracy on both matrices and has been successfully applied to samples from some rats subjected to the preliminary study. The obtained data will hopefully contribute to the clarification of possible differences between depressed and non-depressed subjects with respect to benzodiazepine biotransformation. 相似文献
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Pastorino L Erokhina S Soumetz FC Bianchini P Konovalov O Diaspro A Ruggiero C Erokhin V 《Journal of colloid and interface science》2011,357(1):56-62
The protein collagen is the major component of connective tissue and it is involved in many biological functions. Its degradation is at the basis of different pathological processes. The up-regulated expression of matrix metalloproteinases and the down-regulated expression of their inhibitors are the causes for such degradation. The aim of this work was to evaluate the possibility to fabricate collagen based containers for drug encapsulation and release by cellular demand by the action of matrix metalloproteinases. In present work collagen type I based microcapsules were fabricated by means of the layer-by-layer assembly of oppositely charged collagen and poly (stirene sulfonate) onto colloidal particles, followed by removal of the cores to obtain hollow microcapsules. The process of shell growth on planar supports was monitored by quartz crystal microbalance. X-ray reflectivity measurements were carried out at the solid/water interface to study the interaction of matrix metalloproteinase 1 with LbL films of collagen. The morphology of hollow capsules was characterized by scanning electron microscopy, and compared to that of capsules exposed to the matrix metalloproteinase 1. Finally the matrix metalloproteinase 1 mediated permeability of capsules variation was studied by Confocal Laser Scanning Microscopy. The results demonstrated the possibility to fabricate a drug delivery system where the release of the drug is dependent on the biochemistry of the pathological state. 相似文献
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Carmelina Frammartino 《Applied mathematics and computation》2009,215(1):100-109
A Nyström method is proposed for solving Fredholm integral equations equivalent to special boundary value problems of order 2s. The stability and the convergence of the proposed procedure is proved. Some numerical examples are provided in order to illustrate the accuracy of the method. 相似文献
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Carmelina Frammartino 《Applied mathematics and computation》2010,215(12):4141-4153
A Nyström method is proposed for solving Fredholm integral equations equivalent to boundary value problems of order s with complete differential equations. The stability and the convergence of the proposed procedure are proved. Some numerical examples are provided in order to illustrate the accuracy of the method and to compare the procedure with some other ones given in the literature. 相似文献
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Carmelina Abagnale Francesco Aggogeri Alberto Borboni Salvatore Strano Mario Terzo 《Meccanica》2017,52(9):2189-2199
State estimation in hydraulic actuators is a fundamental technique for fault detection and it is also a valid tool useful to reduce the installation of sensors. The performance of the linear/linearization based techniques for the state estimation is strongly limited due to hard nonlinearities that characterize hydraulic actuator. One of the most common hard nonlinearities in hydraulic actuator is the dead-zone. This paper focuses on an alternative nonlinear estimation method that is able to fully take into account dead-zone hard nonlinearity and measurement noise. The estimator is based on the state-dependent-Riccati-equation (SDRE). A fifth order nonlinear model is derived and employed for the synthesis of the estimator. Several simulations have been conducted in order to analyse the effect of the dead-zone characteristic on the novel estimator performance, showing comparisons with the largely used extended Kalman filter (EKF). Numerical results demonstrate the effectiveness of SDRE based technique in applications characterized by extended dead-zone for which the EKF method provides poor results. 相似文献
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On polynomial collocation for second kind integral equations with fixed singularities of Mellin type
Summary. We consider a polynomial collocation for the numerical solution of a second kind integral equation with an integral kernel
of Mellin convolution type. Using a stability result by Junghanns and one of the authors, we prove that the error of the approximate
solution is less than a logarithmic factor times the best approximation and, using the asymptotics of the solution, we derive
the rates of convergence. Finally, we describe an algorithm to compute the stiffness matrix based on simple Gau? quadratures
and an alternative algorithm based on a recursion in the spirit of Monegato and Palamara Orsi. All together an almost best
approximation to the solution of the integral equation can be computed with 𝒪(n
2[log n]2) resp. 𝒪(n
2) operations, where n is the dimension of the polynomial trial space.
Received February 18, 2002 / Revised version received May 15, 2002 / Published online October 29, 2002
RID="⋆"
ID="⋆" Correspondence to: A. Rathsfeld
Mathematics Subject Classification (1991): 65R20 相似文献
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Giambattista Consiglio Sylvia C. A. Nefkens Carmelina Pisano Fritz Wenzinger 《Helvetica chimica acta》1991,74(2):323-325
The regioselectivity of the hydro-alkoxycarbonylation of methyl acrylate, methacrylate, and crotonate catalyzed by [PdCl2L2] complexes (L = phosphine ligands) can be largely controlled by variation of the ligands. PPh3, promotes preferential carbonylation at the α-position, whereas with [(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis-(methylene)]bis[diphenylphosphine] as ligand, the β-position is overwhelmingly carbonylated. 相似文献
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Habibi N Pastorino L Soumetz FC Sbrana F Raiteri R Ruggiero C 《Colloids and surfaces. B, Biointerfaces》2011,88(1):366-372
Nanostructured polymeric capsules are regarded as highly promising systems with different potential applications ranging from drug delivery, biosensing and artificial cells. To fully exploit this potential, it is required to produce bio-activated stable and biocompatible capsules. To this purpose, in present work we proposed the combination of the layer-by-layer self assembly method with bacterial S-layer technology to fabricate stable and biocompatible polymeric capsules having a well defined arrangement of functional groups allowing the covalent attachment of antibody molecules. Hollow microcapsules were obtained by the layer-by-layer self assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at acidic pH. S-layers were crystallized onto the shell of the obtained capsules. Quartz crystal microbalance was used to characterize the crystallization process onto planar surfaces. S-layer containing capsules were investigated by atomic force microscopy. Immunoenzymatic tests were performed to assess the effective modification of the S-layer with antibody molecules both on planar surfaces and on hollow capsules. Fluorescent microscopy was employed to visualize the presence of the antibody molecules onto the capsule shell and immunological tests used to assess the bioactivity of the immobilized antibodies. Finally, the in vitro cytotoxicity of fabricated S-layer containing capsules was studied. The obtained results demonstrated the possibility to fabricate bio-activated S-layer containing capsules with improved features in terms of biocompatibility. 相似文献
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