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51.
    
The manipulation of interfacial properties has broad implications for the development of high‐performance coatings. Metal–phenolic networks (MPNs) are an emerging class of responsive, adherent materials. Herein, host–guest chemistry is integrated with MPNs to modulate their surface chemistry and interfacial properties. Macrocyclic cyclodextrins (host) are conjugated to catechol or galloyl groups and subsequently used as components for the assembly of functional MPNs. The assembled cyclodextrin‐based MPNs are highly permeable (even to high molecular weight polymers: 250–500 kDa), yet they specifically and noncovalently interact with various functional guests (including small molecules, polymers, and carbon nanomaterials), allowing for modular and reversible control over interfacial properties. Specifically, by using either hydrophobic or hydrophilic guest molecules, the wettability of the MPNs can be readily tuned between superrepellency (>150°) and superwetting (ca. 0°).  相似文献   
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There is an increasing interest in machine learning (ML) algorithms for predicting patient outcomes, as these methods are designed to automatically discover complex data patterns. For example, the random forest (RF) algorithm is designed to identify relevant predictor variables out of a large set of candidates. In addition, researchers may also use external information for variable selection to improve model interpretability and variable selection accuracy, thereby prediction quality. However, it is unclear to which extent, if at all, RF and ML methods may benefit from external information. In this paper, we examine the usefulness of external information from prior variable selection studies that used traditional statistical modeling approaches such as the Lasso, or suboptimal methods such as univariate selection. We conducted a plasmode simulation study based on subsampling a data set from a pharmacoepidemiologic study with nearly 200,000 individuals, two binary outcomes and 1152 candidate predictor (mainly sparse binary) variables. When the scope of candidate predictors was reduced based on external knowledge RF models achieved better calibration, that is, better agreement of predictions and observed outcome rates. However, prediction quality measured by cross-entropy, AUROC or the Brier score did not improve. We recommend appraising the methodological quality of studies that serve as an external information source for future prediction model development.  相似文献   
53.
This article deals with non-linear model parameter estimation from experimental data. As for non-linear models a rigorous identifiability analysis is difficult to perform, parameter estimation is performed in such a way that uncertainty in the estimated parameter values is represented by the range of model use results when the model is used for a certain purpose. Using this approach, the article presents a simulation study where the objective is to discover whether the estimation of model parameters can be improved, so that a small enough range of model use results is obtained. The results of the study indicate that from plant measurements available for the estimation of model parameters, it is possible to extract data that are important for the estimation of model parameters relative to a certain model use. If these data are improved by a proper measurement campaign (e.g. proper choice of measured variables, better accuracy, higher measurement frequency) it is to be expected that a valid model for a certain model use will be obtained. The simulation study is performed for an activated sludge model from wastewater treatment, while the estimation of model parameters is done by Monte Carlo simulation.  相似文献   
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Several copper(I) and copper(II) complexes supported by hemilabile bis(pyrazolylmethyl)amine (pzma) ligands are synthesized and structurally characterized. The copper(I) complexes with hexafluoridophosphate or perchlorate anions are employed as catalysts for the tyrosinase-like oxygenation of 2,4-di-tert-butylphenol (DTBP-H). Their activities are comparable to that of [Cu(MeCN)2PMP]PF6 (PMP= pyrazolylmethylpyridine) investigated earlier. In contrast to the copper(I) pzma complexes, their congeners supported by non-hemilabile bis(pyrazolylethyl)amine (pzea) ligands are found to be catalytically inactive.  相似文献   
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This study is aimed at investigating the microbiocidal potential of amino‐functionalized poly(norbornenes) in the solid state. A series of norbornene‐type monomers that carry secondary or tertiary amine functions as well as hexyl and dodecyl groups were prepared. Ring‐opening metathesis polymerization was used to prepare homopolymers of the amine bearing monomers and random copolymers of amine‐ and alkyl‐substituted monomers of high average molar mass. The resulting polymers were characterized by nuclear magnetic resonance, thermogravimetry, differential scanning calorimetry, infrared spectroscopy, and contact angle measurements, and their contact biocidal potential was evaluated according to the Japanese Industry standard Z2801. Tested microorganisms comprised Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus niger. Microbiocidal activity of selected polymer films against E. coli, S. aureus, and A. niger was found, whereas against C. albicans and P. aeruginosa microbiostatic behavior was observed. Moreover, the most potent copolymer revealed no cytotoxicity rendering a biocidal polymer with potential applications in mammalian‐, and in particular, human‐related fields. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010  相似文献   
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The mechanistic details of the initial steps of the polymerization brought about by a dicyclopentadienyl yttriumhydrid catalyst have been computationally investigated using approximate density functional theory. In accord with the experimental information, the overall reaction sequence Cp2YH + C2H4 → Cp2Y–C2H5 and Cp2YH + C3H6 → Cp2Y–C3H7 is computed to be exothermic by ca. 22.2 and 20.8 kcal mol–1, respectively. The reaction mechanism predicted by our calculations is in harmony with the available experimental information but provides additional information into the various elementary steps of this reaction, which could not be obtained by experimental means.  相似文献   
59.
The molecule HTI, which combines hemithioindigo and hemistilbene molecular parts, allows reversible switching between two isomeric states. Photochromic behaviour of the HTI molecule is observed by irradiation with UV/Vis light. The photochemical reaction, a Z/E isomerization around the central double bond connecting the two molecular parts, is investigated by transient absorption and emission spectroscopy. For a special HTI molecule, namely, an omega-amino acid, the Z-->E isomerization process occurs on a timescale of 30 ps. In the course of the reaction fast processes on the 1-10 ps timescale are observed which point to motions of the molecule on the potential-energy surface of the excited state. The combination of transient absorption experiments in the visible spectral range with time-resolved fluorescence and infrared measurements reveal a photochemical pathway with three intermediate states. Together with a theoretical modelling procedure the experiments point to a sequential reaction scheme and give indications of the nature of the involved intermediates.  相似文献   
60.
    
Coffee is an important agricultural product grown worldwide and one of the most consumed beverages in the world. However, its consumption produces a large amount of waste that can be used in industry, benefiting the environment. Thus, the objective of this work was to pyrolyze spent coffee ground generated through the extraction of the coffee beverage (hot aqueous extraction) using two types of coffee, the traditional and the decaffeinated one, and subsequently apply the acid-base-neutral extraction technique to produce bio-oils. This approach aims to isolate nitrogenous compounds, based on the industrial and pharmacological importance of this class of compounds. The acid-base-neutral extraction technique used is simple, of low cost, and aims to pre-concentrate the nitrogenous compounds based on the basic character given by the nitrogen present in these molecules. The analysis of crude bio-oils (before the fractionation) and the respective fractions was performed by gas chromatography-Quadrupole-mass spectrometry. The bio-oils showed high levels of fatty acids, hydrocarbons, and other oxygen compounds, with only traces of nitrogenated compounds being identified. The acid-base-neutral extraction, after solvent recovery, allowed pre-concentration of these compounds and their identification, highlighting quinolines among the most important compounds and with the greatest biotechnological application.  相似文献   
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