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71.
Beck B Larbig G Mejat B Magnin-Lachaux M Picard A Herdtweck E Dömling A 《Organic letters》2003,5(7):1047-1050
[reaction: see text] A general strategy toward macrocyclic compounds using multicomponent reaction (MCR) chemistry, e.g., Passerini and Ugi variants, and ring-closing metathesis (RCM) is introduced. The corresponding bifunctional isocyanides carboxylic acids bearing a terminal olefin are easy to prepare from the corresponding commercially available starting materials. Advantageously, this strategy allows fast access to a diverse conformational space of natural product-like macrocycles and could thus be of interest in the discovery of novel bioactive agents. 相似文献
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Square planar complexes of the type [2-(1-aminoethyl)phenyl-kappa(2)C(1),N]chloro(py-kappaN)palladium(II)(py = pyridine derivative) have been prepared by cyclopalladation of 1-phenylethylamine. When opposite enantiomers of the chiral amine and different pyridine ligands were coordinated to the metal, quasiracemic complexes were obtained. The racemisation speed of solutions containing equimolar amounts of such quasiracemic complexes was used to test the compounds for inertness: slow ligand exchange was found for methylated pyridines. Enantiomerically pure complexes of opposite chirality with the electron rich ligands 2,6-collidine and 2,4,6-lutidine were successfully cocrystallised: they form a well-ordered binary solid in which four independent molecules, two of each constituent, are related by pseudo symmetry operations. This quasiracemate as well as its components and the true racemates of the latter were characterised by single crystal X-ray diffraction. The heterochiral crystals, both the cocrystal as well as the racemates, show better space filling than the homochiral solids. 相似文献
74.
Spezia S Bocca B Forte G Gatti A Mincione G Ronchi A Bavazzano P Alimonti A Minoia C 《Rapid communications in mass spectrometry : RCM》2005,19(11):1551-1556
In recent years the increasing use of platinum (Pt) both in medical and in industrial applications has caused its growing anthropogenic emission and spread in the environment. Pt is released into the atmosphere by exhaust catalytic converters, and Pt compounds are often used in antitumour therapies. As a consequence, significant amounts of Pt can be detected in hospital wastewaters. This can lead to an increase in the exposure levels to Pt, especially in urban areas. It is therefore necessary to determine Pt reference values in the general population, by using suitable procedures able to achieve adequate analytical performances. Several measurements of Pt in biological fluids have been reported, but the analytical methods used for the determination of Pt often lack information about the uncertainty of the results, especially for low concentrations of urinary Pt in non-occupationally exposed subjects. The present paper considers the measurement of urinary Pt levels in a general population group from central Italy, by both quadrupole (Q) and sector field (SF) inductively coupled plasma mass spectrometry (ICP-MS). The two procedures were validated and their expanded uncertainties were evaluated. The limits of detection (LODs), calculated taking into account dilution factors, were 0.18 and 0.05 ng L(-1) of Pt for the Q and SF procedures, respectively. The median value observed was 4.13 ng L(-1) of Pt in urine, while the relative combined uncertainty at 5 ng L(-1) was below 20% with both ICP-MS techniques. These data are in good agreement with those reported in the literature for similar studies. 相似文献
75.
Alberto Porta Francesca Gelpi Vlasta Bari Beatrice Cairo Beatrice De Maria Cora May Panzetti Noemi Cornara Enrico Giuseppe Bertoldo Valentina Fiolo Edward Callus Carlo De Vincentiis Marianna Volpe Raffaella Molfetta Valeria Pistuddi Marco Ranucci 《Entropy (Basel, Switzerland)》2022,24(1)
Cerebrovascular control is carried out by multiple nonlinear mechanisms imposing a certain degree of coupling between mean arterial pressure (MAP) and mean cerebral blood flow (MCBF). We explored the ability of two nonlinear tools in the information domain, namely cross-approximate entropy (CApEn) and cross-sample entropy (CSampEn), to assess the degree of asynchrony between the spontaneous fluctuations of MAP and MCBF. CApEn and CSampEn were computed as a function of the translation time. The analysis was carried out in 23 subjects undergoing recordings at rest in supine position (REST) and during active standing (STAND), before and after surgical aortic valve replacement (SAVR). We found that at REST the degree of asynchrony raised, and the rate of increase in asynchrony with the translation time decreased after SAVR. These results are likely the consequence of the limited variability of MAP observed after surgery at REST, more than the consequence of a modified cerebrovascular control, given that the observed differences disappeared during STAND. CApEn and CSampEn can be utilized fruitfully in the context of the evaluation of cerebrovascular control via the noninvasive acquisition of the spontaneous MAP and MCBF variability. 相似文献
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Beatrice Nicolaï P. Espeau R. Céolin M. -A. Perrin L. Zaske J. Giovannini F. Leveiller 《Journal of Thermal Analysis and Calorimetry》2007,90(2):337-339
Spironolactone (C24H32O4S) usually crystallizes into an orthorhombic phase, named Form II. Another orthorhombic phase, named Form I, is also known
but seems difficult to obtain. Studies of the kinetics of desolvation of the ethanol solvate at room temperature showed that
these two forms can be obtained through different mechanisms of desolvation. 相似文献
80.
α-Well-posedness for Nash Equilibria and For Optimization Problems with Nash Equilibrium Constraints
We present the concepts of α-well-posedness for parametric noncooperative games and for optimization problems with constraints defined by parametric Nash equilibria. We investigate some classes of functions that ensure these types of well-posedness and the connections with α-well-posedness for variational inequalities and optimization problems with variational inequality constraints. 相似文献