New, faster methods have been developed for analysis of vitamin D and triacylglycerols that eliminate hours of wet chemistry and preparative chromatography, while providing more information than classical methods for analysis. Unprecedented detail is provided by combining liquid chromatography with the power of three or four mass spectrometers used simultaneously, in parallel, for definitive analysis of the vitamins and lipids in dietary supplements. 相似文献
The bulky, but symmetrically beautiful, adamantane ring system is now pervasive throughout physical, medicinal and synthetic chemistry, since it was first discovered in 1924 and coined “dekaterpene”. This fascinating name lived up to its natural product roots when adamantane was isolated from crude oil in 1933, but it was not until 1957 in a landmark contribution by Paul von Ragué Schleyer that adamantane was made readily accessible through synthesis. Beyond the legacy to physical and medicinal chemistry, the adamantane moiety has been quintessential in the development of some of the most important catalysts to date. Considering adamantane's impact on catalyst development past, present and future, this subject is for the first time reviewed herein.
Under basic conditions in alcoholic solvents, bromoenynamides undergo palladium‐catalyzed cyclization to cyclic 2‐amidodienes in good to excellent yields. This process represents the first use of an alcohol as a hydride source in an alkyne carbopalladation/termination sequence, with the site selectivity of the reduction showing a strong dependence on the tethering ring size (5–8), and the nature of the alcohol and base. Reaction of the dienes with a range of dienophiles (including alkenes, alkynes and arynes) under various conditions gives bi‐ and tricyclic azacycles, which can be further oxidized to the aromatic azacycles. 相似文献
Abstract Performance guarantees for multinomial selection procedures are usually derived by finding the least favorable configuration (LFC)—the one for which the probability of correct selection is minimum outside the indifference zone—and then evaluating the procedure on that configuration. The slippage configuration has been proved to be the LFC for several procedures and has been conjectured to be the worst for some other procedures. The principal result of this article unifies and extends all previous results for two alternatives: the slippage configuration is the worst for all procedures that have a finite expected number of trials and always select the alternative with more successes. A generalization of the key inequality in the proof to an arbitrary number of alternatives is conjectured. 相似文献
Abstract Divalent copper and zinc complexes with metal:azole ratio 1∶2 were readily formed at room temperature with the fungicides tebuconazole and propiconazole. The structure of copper and zinc tebuconazole acetate and zinc cis‐propiconazole chloride were examined by X‐ray crystallography. In copper tebuconazole acetate, the copper atom lies on a crystallographic inversion center and is coordinated to two triazole and two acetate ligands in a trans arrangement. The two binding tebuconazole N atoms and two close binding acetate O atoms form a square plane. The two remaining acetate O atoms have more distant interactions, thus forming an elongated octahedron around the copper atom. The coordination geometry of zinc tebuconazole acetate is tetrahedral and the metal is bound to two triazole and two acetate ligands. The geometry is distorted from regular owing to the size of the tebuconazole ligands. The butyl chains are less folded than for the copper tebuconazole complex, resulting in a more extended molecule. The coordination geometry of zinc cis‐propiconazole chloride is also tetrahedral with the metal atom bonded to two triazole and two chloride ligands. 相似文献
We have developed a fusion protein (CBD-LG) incorporating a cellulose-binding domain and an antibody binding domain, protein LG, to provide an adaptor molecule for cell separation with regenerated cellulose hollow fiber arrays. A single hollow fiber cell adhesion assay utilizing a CD34+ cell line, KG1a, was used to investigate whether ligand affinity interactions were strong enough for cell attachment and separation. CBD-LG efficiently captured CD34+ cells labeled with the mouse IgG2a monoclonal antibody MHCD3400. However, it was not possible to bind CD34+ cells labeled with an IgG1 antibody (HPCA-2). The low affinity of HPCA-2 for LG was overcome by secondary antibodies: KG1a cells that were dual labeled with HPCA-2 followed by rat anti-mouse IgG1 adhered inside hollow fibers coated with CBD-LG. Alternatively, immobilized rabbit polyclonal anti-mouse IgG1 captured cells labeled with HPCA-2. The development of an adaptor molecule to display recombinant domains at the surface of hollow fibers will be an effective tool to investigate cellular ligand-receptor interactions, a necessary step in the development of hollow fiber bioreactors for manufacture of human cellular products. 相似文献
Further chemical optimization of the halopemide‐derived family of dual phospholipase D1/2 (PLD1/2) inhibitors afforded ML395 (VU0468809), a potent, >80‐fold PLD2 selective allosteric inhibitor (cellular PLD1, IC50>30 000 nM ; cellular PLD2, IC50=360 nM ). Moreover, ML395 possesses an attractive in vitro DMPK profile, improved physiochemical properties, ancillary pharmacology (Eurofins Panel) cleaner than any other reported PLD inhibitor, and has been found to possess interesting activity as an antiviral agent in cellular assays against a range of influenza strains (H1, H3, H5 and H7). 相似文献
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