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71.
Michele Menotta Sara Biagiotti Laura Streppa Luigia Rossi Mauro Magnani 《Analytica chimica acta》2015
In the present paper we describe an atomic force microscopy (AFM)-based method for the quantitative analysis of FK506 (Tacrolimus) in whole blood (WB) samples. Current reference methods used to quantify this immunosuppressive drug are based on mass spectrometry. In addition, an immunoenzymatic assay (ELISA) has been developed and is widely used in clinic, even though it shows a small but consistent overestimation of the actual drug concentration when compared with the mass spectrometry method. The AFM biosensor presented herein utilises the endogen drug receptor, FKBP12, to quantify Tacrolimus levels. The biosensor was first assayed to detect the free drug in solution, and subsequently used for the detection of Tacrolimus in blood samples. The sensor was suitable to generate a dose–response curve in the full range of clinical drug monitoring. A comparison with the clinically tested ELISA assay is also reported. 相似文献
72.
Two new marine sediment standard reference materials (SRMs) for the determination of organic contaminants 总被引:3,自引:0,他引:3
Wise SA Poster DL Schantz MM Kucklick JR Sander LC Lopez de Alda M Schubert P Parris RM Porter BJ 《Analytical and bioanalytical chemistry》2004,378(5):1251-1264
Two new marine sediment standard reference materials (SRMs), SRM 1941b Organics in Marine Sediment and SRM 1944 New York/New Jersey Waterway Sediment, have been recently issued by the National Institute of Standards and Technology (NIST) for the determination of organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) congeners, and chlorinated pesticides. Both sediment SRMs were analyzed using multiple analytical methods including gas chromatography/mass spectrometry (GC/MS) on columns with different selectivity, reversed-phase liquid chromatography with fluorescence detection (for PAHs only), and GC with electron capture detection (for PCBs and pesticides only). SRM 1941b has certified concentrations for 24 PAHs, 29 PCB congeners, and 7 pesticides, and SRM 1944 has certified concentrations for 24 PAHs, 29 PCB congeners, and 4 pesticides. Reference concentrations are also provided for an additional 58 (SRM 1941b) and 39 (SRM 1944) PAHs, PCB congeners, and pesticides. SRM 1944, which was collected from multiple sites within New York/New Jersey coastal waterways, has contaminant concentrations that are generally a factor of 10–20 greater than SRM 1941b, which was collected in the Baltimore (Maryland) harbor. These two SRMs represent the most extensively characterized marine sediment certified reference materials available for the determination of organic contaminants.Electronic Supplementary Material Supplementary material is available in the online version of this article at . A link in the frame on the left on that page takes you directly to the supplementary material. 相似文献
73.
The study and the exploitation of membrane proteins for drug screening applications requires a controllable and reliable method for their delivery into an artificial suspended membrane platform based on lab-on-a-chip technology. In this work, a polymeric device for forming lipid bilayers suitable for electrophysiology studies and biosensor applications is presented. The chip supports a single bilayer and is configured for controlled protein delivery through on-chip microfluidics. In order to demonstrate the principle of protein delivery, the potassium channel KcsA was reconstituted into proteoliposomes, which were then fused with the suspended bilayer on-chip. Fusion of single proteoliposomes with the membrane was identified electrically. Single channel conductance measurements of KcsA in the on-chip bilayer were recorded and these were compared to previously published data obtained with a conventional planar bilayer system. 相似文献
74.
Werner Seebacher Marcel Kaiser Reto Brun Robert Saf Robert Weis 《Monatshefte für Chemie / Chemical Monthly》2007,138(7):709-714
Summary. We synthesized several 4-aminobicyclo[2.2.2] octan-2-ols and 4-amino-2-azabicyclo[3.2.2]nonanes from epimerized 4-amino-bicyclo[2.2.2]octan-2-ones.
The new compounds were tested for their activity against Trypanosoma b. rhodesiense, the causative organism of East African sleeping sickness, and Plasmodium falciparum K
1, a multiresistant protozoan parasite which causes Malaria tropica. The results are compared to the activities of their formerly
synthesized stereoisomers and structure–activity relationships are discussed. 相似文献
75.
A new algorithm for density-functional-theory-based ab initio molecular dynamics simulations is presented. The Kohn–Sham
orbitals are expanded in Gaussian-type functions and an augmented-plane-wave-type approach is used to represent the electronic
density. This extends previous work of ours where the density was expanded only in plane waves. We describe the total density
in a smooth extended part which we represent in plane waves as in our previous work and parts localised close to the nuclei
which are expanded in Gaussians. Using this representation of the charge we show how the localised and extended part can be
treated separately, achieving a computational cost for the calculation of the Kohn–Sham matrix that scales with the system
size N as O(NlogN). Furthermore, we are able to reduce drastically the size of the plane-wave basis. In addition, we introduce a multiple-cutoff
method that improves considerably the performance of this approach. Finally, we demonstrate with a series of numerical examples
the accuracy and efficiency of the new algorithm, both for electronic structure calculations and for ab initio molecular dynamics
simulations.
Received: 15 December 1998 /Accepted: 18 February 1999 /Published online: 14 July 1999 相似文献
76.
Prof. Domenico C. M. Albanese Dr. Michele Penso 《European journal of organic chemistry》2023,26(19):e202300224
Phase Transfer Catalysis (PTC) is a powerful tool to perform reactions in a practical fashion, both in laboratory and industrial scale. Significant cost savings and major process improvements can be achieved in reactions performed under PTC conditions. In the last few years remarkable results in stereoselective reactions were achieved using chiral, non-racemic quaternary ammonium salts. Moreover, the use of bulky, chiral phosphate anions paired with achiral cations to generate lipophilic ion pairs allowed to design new avenues for the stereoselective construction of important building blocks. Hydrogen bond interactions were also shown to provide new pathways for asymmetric nucleophilic substitutions using insoluble reagents under PTC conditions. This Review will focus on recent advances in developing practical synthetic routes to construct molecules in a stereoselective fashion under PTC conditions. 相似文献
77.
Michael R. Smith Clare B. Martin Sonia Arumuganainar Ari Gilman Bruce E. Koel Michele L. Sarazen 《Angewandte Chemie (International ed. in English)》2023,62(8):e202218208
Immobilization of porphyrin complexes into crystalline metal–organic frameworks (MOFs) enables high exposure of porphyrin active sites for CO2 electroreduction. Herein, well-dispersed iron-porphyrin-based MOF (PCN-222(Fe)) on carbon-based electrodes revealed optimal turnover frequencies for CO2 electroreduction to CO at 1 wt.% catalyst loading, beyond which the intrinsic catalyst activity declined due to CO2 mass transport limitations. In situ Raman suggested that PCN-222(Fe) maintained its structure under electrochemical bias, permitting mechanistic investigations. These revealed a stepwise electron transfer-proton transfer mechanism for CO2 electroreduction on PCN-222(Fe) electrodes, which followed a shift from a rate-limiting electron transfer to CO2 mass transfer as the potential increased from −0.6 V to −1.0 V vs. RHE. Our results demonstrate how intrinsic catalytic investigations and in situ spectroscopy are needed to elucidate CO2 electroreduction mechanisms on PCN-222(Fe) MOFs. 相似文献
78.
Robert Weis Reto Brun Robert Saf Werner Seebacher 《Monatshefte für Chemie / Chemical Monthly》2003,134(7):1019-1026
Summary. 4-Aminobicyclo[2.2.2]octanones which were prepared in one-pot-reactions from benzylidene acetone and dialkylammonium rhodanides
were reduced stereoselectively to their corresponding alcohols. The activities of the bicyclic compounds against causative
organisms of tropical deseases were examined. The 4-aminobicyclo[2.2.2]octan-2-ols were in general more active against Trypanosoma b. rhodesiense and Plasmodium falciparum than the corresponding keto compounds.
Corresponding author. E-mail: robert.weis@uni-graz.at
Received November 27, 2002; accepted December 2, 2002
Published online May 2, 2003 相似文献
79.
We remove the nonuniqueness of the embedding potential that exists in most previous quantum mechanical embedding schemes by letting the environment and embedded region share a common embedding (interaction) potential. To efficiently solve for the embedding potential, an optimized effective potential method is derived. This embedding potential, which eschews use of approximate kinetic energy density functionals, is then used to describe the environment while a correlated wavefunction (CW) treatment of the embedded region is employed. We first demonstrate the accuracy of this new embedded CW (ECW) method by calculating the van der Waals binding energy curve between a hydrogen molecule and a hydrogen chain. We then examine the prototypical adsorption of CO on a metal surface, here the Cu(111) surface. In addition to obtaining proper site ordering (top site most stable) and binding energies within this theory, the ECW exhibits dramatic changes in the p-character of the CO 4σ and 5σ orbitals upon adsorption that agree very well with x-ray emission spectra, providing further validation of the theory. Finally, we generalize our embedding theory to spin-polarized quantum systems and discuss the connection between our theory and partition density functional theory. 相似文献
80.