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221.
A pentadentate salen-type ligand was immobilized in a poly[(styrene)]-co-(butyl acrylate)] matrix by miniemulsion polymerization. The obtained polymer beads revealed a particle size of 50 nm in the dry state by transmission electron microscopy. Dynamic light scattering experiments in methanol and water showed a solvent-dependent average particle size with a mean particle diameter of up to 233 nm in methanol. These results provide valuable insights for the optimization of macromolecular oxidation catalysts and their future use as enzyme-like entities in aqueous media. The particle stability was demonstrated over a wide pH range (3-11) by gel permeation chromatography, and initial results for the metal ion binding ability were obtained. 相似文献
222.
Nadler Natasha; Delgado Mauricio R.; Delamater Andrew R. 《Canadian Metallurgical Quarterly》2011,11(5):1112
Pavlovian learning tasks have been widely used as tools to understand basic cognitive and emotional processes in humans. The present studies investigated one particular task, Pavlovian-to-instrumental transfer (PIT), with human participants in an effort to examine potential cognitive and emotional effects of Pavlovian cues upon instrumentally trained performance. In two experiments, subjects first learned two separate instrumental response-outcome relationships (i.e., R1-O1 and R2-O2) and then were exposed to various stimulus-outcome relationships (i.e., S1-O1, S2-O2, S3-O3, and S4-) before the effects of the Pavlovian stimuli on instrumental responding were assessed during a non-reinforced test. In Experiment 1, instrumental responding was established using a positive-reinforcement procedure, whereas in Experiment 2, a quasi-avoidance learning task was used. In both cases, the Pavlovian stimuli exerted selective control over instrumental responding, whereby S1 and S2 selectively elevated the instrumental response with which it shared an outcome. In addition, in Experiment 2, S3 exerted a nonselective transfer of control effect, whereby both responses were elevated over baseline levels. These data identify two ways, one specific and one general, in which Pavlovian processes can exert control over instrumental responding in human learning paradigms, suggesting that this method may serve as a useful tool in the study of basic cognitive and emotional processes in human learning. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
223.
Toxic cyanobacterial breakthrough and accumulation in a drinking water plant: a monitoring and treatment challenge 总被引:1,自引:0,他引:1
Zamyadi A MacLeod SL Fan Y McQuaid N Dorner S Sauvé S Prévost M 《Water research》2012,46(5):1511-1523
The detection of cyanobacteria and their associated toxins has intensified in recent years in both drinking water sources and the raw water of drinking water treatment plants (DWTPs). The objectives of this study were to: 1) estimate the breakthrough and accumulation of toxic cyanobacteria in water, scums and sludge inside a DWTP, and 2) to determine whether chlorination can be an efficient barrier to the prevention of cyanotoxin breakthrough in drinking water. In a full scale DWTP, the fate of cyanobacteria and their associated toxins was studied after the addition of coagulant and powdered activated carbon, post clarification, within the clarifier sludge bed, after filtration and final chlorination. Elevated cyanobacterial cell numbers (4.7 × 106 cells/mL) and total microcystins concentrations (up to 10 mg/L) accumulated in the clarifiers of the treatment plant. Breakthrough of cells and toxins in filtered water was observed. Also, a total microcystins concentration of 2.47 μg/L was measured in chlorinated drinking water. Cyanobacterial cells and toxins from environmental bloom samples were more resistant to chlorination than results obtained using laboratory cultured cells and dissolved standard toxins. 相似文献
224.
We developed a novel two-dimensional (2-D) crystalline colloidal array photonic crystal sensing material for the visual detection of amphiphilic molecules in water. A close-packed polystyrene 2-D array monolayer was embedded in a poly(N-isopropylacrylamide) (PNIPAAm)-based hydrogel film. These 2-D photonic crystals placed on a mirror show intense diffraction that enables them to be used for visual determination of analytes. Binding of surfactant molecules attaches ions to the sensor that swells the PNIPAAm-based hydrogel. The resulting increase in particle spacing red shifts the 2-D diffracted light. Incorporation of more hydrophobic monomers increases the sensitivity to surfactants. 相似文献
225.
Electrochemical impedance spectroscopy (EIS) is used to detect 2,4,6-trinitrotoluene (TNT) in a novel sandwiched structure which relies on the specific interactions between (i) primary amine with TNT and (ii) TNT and anti-TNT aptamer. With pure targets, the assay has a sensitivity of 10(-14) M, a dynamic range of 10(-14)-10(-3) M, and employs a small sample volume (25 μL). The method's sensitivity is comparable to state of the art optical methods with the added advantages of electrochemical detection, which can be easily miniaturized and implemented into a hand-held device. 相似文献
226.
227.
This paper details the challenges encountered by authors summarizing evidence from a primary study to describe a treatment's effectiveness using an effect size (ES) estimate. Dilemmas that are encountered, including how to calculate and interpret the pertinent standardized mean difference ES for results from studies of various research designs, are described. Recommendations are offered to authors of primary studies and to those conducting summaries of primary studies. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
228.
Latex films have a tendency to "blush" when exposed to water. The swelling of trapped hydrophilic material, which results in pockets with different refractive indices, is proposed as a possible model for blushing. A pressure-sensitive latex was developed on the basis of this model. The blush was improved by the choice of the surfactant and control of the particle diameter. The resulting latex has an unusual particle growth behavior during polymerization. The particle size distribution (PSD) was characterized by dynamic light scattering (DLS), electron microscopy (SEM/TEM) and atomic force microscopy (AFM). The data are in a good agreement with our proposed growth model. 相似文献
229.
Design and evaluation of tiled parallel coordinate visualization of multichannel EEG data 总被引:1,自引:0,他引:1
ten Caat M Maurits NM Roerdink JB 《IEEE transactions on visualization and computer graphics》2007,13(1):70-79
The field of visualization assists data interpretation in many areas, but does not manage all types of data equally well. This holds, in particular, for time-varying multichannel EEG data. No existing method can successfully visualize simultaneous information from all channels in use at all time steps. To address this problem, a new visualization method is presented based on the parallel coordinate method and making use of a tiled organization. This tiled organization employs a two-dimensional row-column representation, rather than a one-dimensional arrangement in columns as used for classical parallel coordinates. The usefulness of the new method, referred to as tiled parallel coordinates (TPC), is demonstrated by a particular type of EEG data. It can be applied to an arbitrary number of time steps, handling the maximum number of channels currently in use. An extensive user evaluation shows that, for a typical EEG assessment task, data evaluation by the TPC method is faster than by an existing clinical EEG visualization method, without loss of information. The generality of the TPC method makes it widely applicable to other time-varying multivariate data types 相似文献
230.
Francesco Alberti Roberto Bruttomesso Silvio Ghilardi Silvio Ranise Natasha Sharygina 《Formal Methods in System Design》2014,45(1):63-109
Lazy abstraction with interpolation-based refinement has been shown to be a powerful technique for verifying imperative programs. In presence of arrays, however, the method suffers from an intrinsic limitation, due to the fact that invariants needed for verification usually contain universally quantified variables, which are not present in program specifications. In this work we present an extension of the interpolation-based lazy abstraction framework in which arrays of unknown length can be handled in a natural manner. In particular, we exploit the Model Checking Modulo Theories framework to derive a backward reachability version of lazy abstraction that supports reasoning about arrays. The new approach has been implemented in a tool, called safari, which has been validated on a wide range of benchmarks. We show by means of experiments that our approach can synthesize and prove universally quantified properties over arrays in a completely automatic fashion. 相似文献