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排序方式: 共有199条查询结果,搜索用时 15 毫秒
81.
Daniel Sabanés Bové Leonhard Held Göran Kauermann 《Journal of computational and graphical statistics》2013,22(2):394-415
We propose an objective Bayesian approach to the selection of covariates and their penalized splines transformations in generalized additive models. The methodology is based on a combination of continuous mixtures of g-priors for model parameters and a multiplicity-correction prior for the models themselves. We introduce our approach in the normal model and extend it to nonnormal exponential families. A simulation study and an application with binary outcome is provided. An efficient implementation is available in the R package hypergsplines. Supplementary materials for this article are available online. 相似文献
82.
We give a characterization, in one variable case, of those multipliers F such that the division problem is solvable in . For these functions we even prove that the multiplication operator has a continuous linear right inverse on , in contrast to what happens in the several variables case, as was shown by Langenbruch. 相似文献
83.
The sound in the acoustic far–field of a round jet is generated by a multitude of unsteady flow structures with different length and time scales. Most likely, different components of the noise spectrum are created by different structures in the jet which emit sound in different directions. Based on Lighthill's acoustic analogy, we present a method for relating flow structures of the jet with far–field noise spectra and their associated directivity patterns. The method allows to determine what kind of noise (with respect to frequency and emission direction) is generated at a given streamwise location. We illustrate the method with numerical results for a round isothermal jet. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
84.
A novel interface adapter has been designed to provide a new way of directly coupling a nano-liquid chromatograph to an electron ionization mass spectrometer. It connects the transfer capillary coming from the liquid chromatograph to the ionization chamber and can be easily screwed into the ion source. Liquid coming from the column passes through the heated adapter flow path and is vaporized. A continuous flow of new liquid pushes the vapor into the ionization chamber where it is ionized and continues on to the mass analyzer. The advantages of the new adapter are reduced ice formation inside the ion source and less clogging of the transfer capillary. Improvements achieved are demonstrated on the basis of caffeine and steroid analysis. The limits of detection of selected steroids are compared with and without the adapter. The adapter improves the detection limit of the system by a factor of 2 and precision from ≤15% to ≤9% relative standard deviation. No derivatization procedure is necessary before the analysis of small polar compounds. The resulting spectra are reproducible, easily interpretable, and database searchable. The new method is robust, delivers reproducible results, and provides a highly efficient alternative to existing methods in the field of pharmaceutical analysis. 相似文献
85.
Walter Keller-Schierlein Leonhard Hagmann Hans Zhner Wolfgang Huhn 《Helvetica chimica acta》1988,71(6):1528-1540
Maduraferrin, a Novel Siderophore from Actinomadura madurae From a strain of Actinomadura madurae, a new siderophore was isolated. Maduraferrin is the Fe complex of an oligopeptide composed of salicylic acid, β-alanine, glycine, L -serine, Nδ-hydroxy-Nα-methyl-L -ornithine, and L -hexahydropyridazine-3-carboxylic acid. The complexing centers are a salicylamide moiety, a hydroxamic-acid group and an acid hydrazide group. 相似文献
86.
87.
The reaction of 4,4′-dihydroxy diphenylsulfide (Ia) and 4,4′-dihydroxydiphenylsulfone (Ib) with hexamethyldisilazane leads to 4,4′-bis)trimethylsiloxy) diphenylsulfide and 4,4′-bis(trimethylsiloxy)diphenylsulfone. Ia and Ib treated with hexamethylcyclotrisilazane form sila-paracyclophanes. 相似文献
88.
Leonhard Birkofer Matthias Bockhorst Alois Steigel Dietmar Eichstadt 《Journal of organometallic chemistry》1982,233(3):291-297
The reductive silylation of 1,3,5-hexatriene (I) with trimethylsilyl chloride and magnesium affords 74% disilylhexadienes, consisting of 8% 1,4-bis(trimethylsilyl)-2,5-hexadiene (II) and 92% 1,6-bis(trimethylsilyl)-2,4-hexadiene (III). The isomers IIIa, IIIb and IIIc can be separated via the Dieis—Alder adducts. Maleic anhydride reacts with IIIa and IIIb to give the bis[(trimethylsilyl)methyl] derivatives of 4-cyclohexene-1,2-dicar?ylic acid anhydride (IVa and IVb), whereas IIIc does not react with maleic anhydride. By a reductive silylation reaction 3-methyl-l,3,5-hexatriene (V) gives the 1,6-bis-silylated 2,4-hexadienes VIa and VIb, which with maleic anhydride give the adducts VIIa and VIIb. 相似文献
89.
Artificial Formation and Tuning of Glycoprotein Networks on Live Cell Membranes: A Single‐Molecule Tracking Study
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Leonhard Möckl Prof. Dr. Thisbe K. Lindhorst Prof. Dr. Christoph Bräuchle 《Chemphyschem》2016,17(6):829-835
We present a method to artificially induce network formation of membrane glycoproteins and show the precise tuning of their interconnection on living cells. For this, membrane glycans are first metabolically labeled with azido sugars and then tagged with biotin by copper‐free click chemistry. Finally, these biotin‐tagged membrane proteins are interconnected with streptavidin (SA) to form an artificial protein network in analogy to a lectin‐induced lattice. The degree of network formation can be controlled by the concentration of SA, its valency, and the concentration of biotin on membrane proteins. This was verified by investigation of the spatiotemporal dynamics of the SA‐protein networks employing single‐molecule tracking. It was also proven that this network formation strongly influences the biologically relevant process of endocytosis as it is known from natural lattices on the cell surface. 相似文献
90.