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821.
Adam Loy Heike Hofmann Dianne Cook 《Journal of computational and graphical statistics》2017,26(3):478-492
The complexity of linear mixed-effects (LME) models means that traditional diagnostics are rendered less effective. This is due to a breakdown of asymptotic results, boundary issues, and visible patterns in residual plots that are introduced by the model fitting process. Some of these issues are well known and adjustments have been proposed. Working with LME models typically requires that the analyst keeps track of all the special circumstances that may arise. In this article, we illustrate a simpler but generally applicable approach to diagnosing LME models. We explain how to use new visual inference methods for these purposes. The approach provides a unified framework for diagnosing LME fits and for model selection. We illustrate the use of this approach on several commonly available datasets. A large-scale Amazon Turk study was used to validate the methods. R code is provided for the analyses. Supplementary materials for this article are available online. 相似文献
822.
Nuha Alharbi Alejandro Díaz-Moscoso Graham J. Tizzard Simon J. Coles Michael J. Cook Andrew N. Cammidge 《Tetrahedron》2014
New tetrabenzotriazaporphyrins are reported that are functionalised at the meso-position. The derivatives functionalised with meso-bromophenyl substituents are synthesised using an improved variation on the traditional reaction between phthalonitriles and Grignard reagents. For all other new derivatives, a modern protocol is employed that gives convenient access to these challenging materials by template co-macrocyclisation between phthalonitriles and aryl-aminoisoindoline derivatives like 15. The newly developed procedure allows design and synthesis of elaborate, functional composites and this is demonstrated by synthesis of meso-pyrenylTBTAP 24, a linked double chromophore in which the two complementary units lie perpendicular to each other and therefore have minimal ground state interaction. 相似文献
823.
824.
A. D. Cook 《Fresenius' Journal of Analytical Chemistry》1906,45(11):713
Ohne Zusammenfassung 相似文献
825.
Herein we describe a new thin film imprinted polymer for propofol (active ingredient of a commonly used general intravenous anaesthetic) developed on a membrane support. Propofol binds to this polymer in 2 min and can be removed and tested in 1 min, giving a total assay time of 3 min. The non-specific binding to the polymer is below the detection limit (0.1 μg/ml) and the response rate is below the rate of metabolism of the anaesthetic. Tests performed with this polymer against propofol-spiked blood samples showed good linearity and specificity at clinically relevant concentrations of 1-10 μg/ml and the working range for the system is 0.1-50 μg/ml. The polymer is easily regenerated and can be re-used for subsequent testing (in blood up to 5000 cycles). These results suggest suitability for use in an on-line propofol detection system. 相似文献
826.
Jennifer M. Dean Robert B. Grubbs Walid Saad Robert F. Cook Frank S. Bates 《Journal of Polymer Science.Polymer Physics》2003,41(20):2444-2456
Block copolymers with and without reactive functionalities can improve fracture resistance in brittle epoxies even when added in relatively small amounts (<5 wt %). At certain compositions, amphiphilic block copolymers spontaneously self‐assemble into vesicles, spherical micelles, or wormlike micelles in thermoset resins, and these morphologies are retained with the full curing of the resins. The addition of such block copolymers leaves the glass‐transition temperature of these blends relatively unchanged, whereas the fracture resistance increases up to a factor of 3.5 for the vesicle‐modified blends. For epoxies modified with block copolymers self‐assembled into a spherical geometry (vesicles or spherical micelles), the fracture resistance scales with the ratio of the interparticle distance to the average vesicle (or spherical micelle) diameter (Di/Dp) and increases as this quantity is reduced. Greater adhesion between the vesicle and epoxy resin improves the fracture resistance only at higher values of Di/Dp, at which the materials are more brittle. Debonding and subsequent matrix plastic deformation are identified as the toughening mechanisms in these blends. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2444–2456, 2003 相似文献
827.
828.
Gulen BerberAndrew N. Cammidge Isabelle ChambrierMichael J. Cook Paul W. Hough 《Tetrahedron letters》2003,44(29):5527-5529
(Monocarbonyl) and bis(benzonitrile)ruthenium phthalocyanines, conveniently prepared from metal-free phthalocyanine precursors, are used as supramolecular building-blocks in the construction of phthalocyanine-porphyrin multi-chromophore arrays. 相似文献
829.
S. Thiam D. Treleaven R. Cook R. E. Tracy J. W. Robinson I. M. Warner 《Journal of Applied Spectroscopy》2004,71(1):94-101
The plaque deposits in bypass arteries and native arteries from the same heart have been studied using solid state cross polarization nuclear magnetic resonance (CP/MAS NMR). Both 13C and 31P signals were observed. The samples are of interest because plaque in native arteries may have deposited during the lifetime of the patient. However, plaque in the bypass occurred since bypass surgery. It has been observed that the mature plaque in native arteries was more calcified than that in bypass arteries, especially if the latter had not matured to become significant in size. Results showed that the concentrations of carboxylate carbons present in cholesterol esters were similar in native and bypass arteries. However, the areas of the 13C peaks of the carboxylate compared to the sum of areas of all other 13C arteries indicated that the carboxylate was attached to five or six other carbons. From this we can calculate that the carboxylate to other carbon ratio in the remainder must be 1:4 or 1:3. This indicates large quantities of other organic compounds in the deposits. Studies of 31P showed that phosphorus existed primarily as hydroxyapatite in the crystalline native plaque. However, a large proportion existed as organic phosphorus in the bypass plaque. In addition, we studied the interactions of calcium with homocysteine and cholesterol. Calcium-homocysteine and cholesterol-homocysteine precipitates were characterized using 13C solid state NMR. Results showed that calcium appeared to interact with sulphur in the homocysteine which seemed to form dimers and polymers. 相似文献
830.
Efficient Access to Multifunctional Trifluoromethyl Alcohols through Base‐Free Catalytic Asymmetric C−C Bond Formation with Terminal Ynamides
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Andrea M. Cook Dr. Christian Wolf 《Angewandte Chemie (International ed. in English)》2016,55(8):2929-2933
The asymmetric addition of terminal ynamides to trifluoromethyl ketones with a readily available chiral zinc catalyst gives CF3‐substituted tertiary propargylic alcohols in up to 99 % yield and 96 % ee. The exclusion of organozinc additives and base as well as the general synthetic utility of the products are key features of this reaction. The value of the β‐hydroxy‐β‐trifluoromethyl ynamides is exemplified by selective transformations to chiral Z‐ and E‐enamides, an amide, and N,O‐ketene acetals. The highly regioselective hydration, stereoselective reduction, and hydroacyloxylation reactions proceed with high yields and without erosion of the ee value of the parent β‐hydroxy ynamides. 相似文献