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991.
The first total synthesis of Ciliatamides A-C was completed, leading to a revision of the reported stereochemistry from (S,S) to the (R,R) enantiomers. Due to the expedited route, a library of over 50 unnatural ciliatamide analogs was also prepared. 相似文献
992.
Schwaighofer A Schroeter T Mika S Hansen K Ter Laak A Lienau P Reichel A Heinrich N Müller KR 《Journal of chemical information and modeling》2008,48(4):785-796
Metabolic stability is an important property of drug molecules that should-optimally-be taken into account early on in the drug design process. Along with numerous medium- or high-throughput assays being implemented in early drug discovery, a prediction tool for this property could be of high value. However, metabolic stability is inherently difficult to predict, and no commercial tools are available for this purpose. In this work, we present a machine learning approach to predicting metabolic stability that is tailored to compounds from the drug development process at Bayer Schering Pharma. For four different in vitro assays, we develop Bayesian classification models to predict the probability of a compound being metabolically stable. The chosen approach implicitly takes the "domain of applicability" into account. The developed models were validated on recent project data at Bayer Schering Pharma, showing that the predictions are highly accurate and the domain of applicability is estimated correctly. Furthermore, we evaluate the modeling method on a set of publicly available data. 相似文献
993.
von Holst C Baeten V Boix A Slowikowski B Fernández Pierna JA Tirendi S Dardenne P 《Analytical and bioanalytical chemistry》2008,392(1-2):313-317
Near-infrared microscopy (NIRM) has been proved to be a powerful tool for the detection of banned meat and bone meal (MBM) in feed. The identification of MBM traces and its ability to differentiate animal from vegetable feed ingredients is based on the evaluation of near-infrared spectra obtained from individual particles present in the sample. This evaluation is supported by appropriate decision rules for the absorbances at specific wavelengths. Here we show that the method and the corresponding decision rules can be successfully transferred from the laboratory which constructed the decision rules to two independent laboratories that were not involved in the calibration process of the method. The analytical results from blind feed samples containing MBM (positive samples) and feed samples without MBM (negative samples) revealed a very good agreement between the three laboratories, thus demonstrating the transferability of the method. 相似文献
994.
995.
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997.
von Helden G Compagnon I Blom MN Frankowski M Erlekam U Oomens J Brauer B Gerber RB Meijer G 《Physical chemistry chemical physics : PCCP》2008,10(9):1248-1256
The experimental mid- and far-IR spectra of six conformers of phenylalanine in the gas phase are presented. The experimental spectra are compared to spectra calculated at the B3LYP and at the MP2 level. The differences between B3LYP and MP2 IR spectra are found to be small. The agreement between experiment and theory is generally found to be very good, however strong discrepancies exist when -NH2 out-of-plane vibrations are involved. The relative energies of the minima as well as of some transition states connecting the minima are explored at the CCSD(T) level. Most transition states are found to be less than 2000 cm(-1) above the lowest energy structure. A simple model to describe the observed conformer abundances based on quasi-equilibria near the barriers is presented and it appears to describe the experimental observation reasonably well. In addition, the vibrations of one of the conformers are investigated using the correlation-corrected vibrational self-consistent field method. 相似文献
998.
999.
The efficacy of photodynamic therapy (PDT) with 5-aminolevulinate and methyl aminolevulinate in the treatment of actinic keratosis has been demonstrated in a large number of clinical studies over the last several years. Here, we recapitulate the major findings, comparing the various photosensitizers, light sources and therapeutic regimens, and present a retrospective analysis of 142 own cases treated with 259 PDTs. In addition, we also discuss the value of PDT in comparison with cryotherapy or 5-fluorouracil. The efficacy and the low risk of side effects of PDT have resulted in a high patient preference in clinical trials. 相似文献
1000.
Carsten von Hänisch PD Dr. 《无机化学与普通化学杂志》2008,634(4):701-703
Synthesis and Metalation of the Diaminosiloxane O(SiiPr2NH2)2 The 1,3‐diaminoldisiloxane O(SiiPr2NH2)2 ( 1 ) was obtained from the reaction of O(SiiPr2Cl)2 with NH3. The reactions of 1 with AlEt3 or GaEt3 produced the compounds [O{SiiPr2N(H)MEt2}{SiiPr2NMEt}]2 ( 2 : M = Al; 3 : M = Ga). The crystal structures of 2 and 3 were determined by single crystal X‐ray diffraction, showing a polycyclic M4N4Si4O2 core structure of these molecules. 相似文献