University of North Texas

About: University of North Texas is a education organization based out in Denton, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 11866 authors who have published 26984 publications receiving 705376 citations. The organization is also known as: Fight, North Texas & UNT.

Consumer innovativeness and perceived risk: implications for high technology product adoption

Abstract: – To investigate consumer innovativeness (CI) from a hierarchical perspective and examine the simultaneous impacts of hierarchical perspective of CI and perceived risk on new product adoption., – An extended innovativeness and perceived risk model was developed. A structural equation model was used to test the hypotheses using empirical data from 746 respondents in a high technology product context., – The results provide support for the hierarchical perspective of CI; domain specific CI mediates the relationship between global CI and new product adoption. Specifically, cognitive and domain‐specific innovativeness enhances the actual adoption of new products; whereas sensory innovativeness and perceived social and physical risks enhance consumers' propensity to acquire novel information about new products. Financial risk, on the other hand, has a negative impact on the propensity to acquire novel information about new products. Time, performance, psychological, and network externalities risks show no significant relations with the tendency to acquire novel information about new products., – The findings provide an explanation to the less than consistent relationship between consumer innovativeness and new product adoption. However, a single research context of high tech consumer goods may be a limitation and future studies need to replicate this hierarchical perspective of CI as a predictor of new product adoption in different research contexts for greater generalizability., – The findings of the study provide some guidelines to marketers on how to increase the new product commercialization success. Marketers should tap into the cognitive and domain‐specific innovativeness to enhance the new product adoption. The sensory part of CI and perceived social and physical risks have implications for the promotion and communication aspects of new product marketing., – Provides new insights about consumer innovativeness trait as a useful predictor of new product adoption.

Fabrication of Monodisperse Gel Shells and Functional Microgels in Microfluidic Devices

Abstract: Microgels are colloidal gel particles that consist of chemically cross-linked three-dimensional polymer networks; these networks are able to dramatically shrink or swell by expelling or absorbing large amounts of water in response to external stimuli. 2] The large change in size can be achieved, for example, by modifying the pH, temperature, or ionic strength of the medium, or by applying electric or magnetic fields; it is this response that makes microgels desirable for applications in drug delivery, biosensing, diagnostics, bioseparations, and optical devices. 10] To further expand their range of applicability, there have been efforts to generate microgels that have been complexed with preformed functionalized materials that impart additional desirable properties to the microgel. These preformed materials range from molecules to microparticles and are typically complexed with the gel matrix through specific interactions. The resulting complexed microgels usually show a drastic decrease in their physical response to external stimuli compared to that of the original cross-linked polymer networks; this is an undesirable side effect since the microgel performance for a given application is based on its sensitivity to external stimuli. In addition to functionality, the size distribution of a population of microgels is important; it is critical to provide a homogeneous distribution of microgels applying formulations and in controlling the release kinetics of encapsulates or adsorbents. From the standpoint of performance and applicability, there is a need for methods to generate monodisperse microgels that maintain high sensitivity to external stimuli irrespective of the materials that are incorporated to add complementary functions. Here, we describe a flexible and straightforward method for generating monodisperse suspensions of new microgelbased materials using a capillary microfluidic technique. This technique enabled us to generate and precisely control the size of the microgel-based particles without sacrificing the physical response of the resulting microgels. We generated two novel microgel structures: a spherical microgel shell and spherical microgel particles that retain their full sensitivity to external stimuli after being physically complexed with preformed colloidal particles. The overall size and thickness of the microgel shells can be tuned with temperature. We generated the spherical microgel particles in a single step, which allows us to freely incorporate functional materials into the polymer network. We used quantum dots, magnetic nanoparticles, and polymer microparticles as examples of the materials that can be added to provide specific chemical, physical, or mechanical properties to the original microgels. To generate the microgel particles, we constructed a capillary-based microfluidic device that generated pre-microgel drops, which were then polymerized in situ with a redox reaction. The capillary microfluidic device was made of three separate capillary tubes. The two internal cylindrical tubes served as injection and collection tubes and were coaxially aligned, as shown in the inset in Figure 1A. These tapered tubes were made by axially heating and pulling cylindrical capillaries. In the region near both tips, the outer fluid focuses both the middle and inner fluids through the collection tube to form a fluid thread that then breaks into drops as a result of hydrodynamic instabilities, as shown in Figure 1A. We typically used silicon oil with viscosity hOF= 125 mPas as the outer, or continuous-phase liquid. The middle fluid was an aqueous monomer solution that contained N-isopropylacrylamide (NIPAm, 15.5% w/v), a crosslinker (N,N’-methylenebisacrylamide, BIS, 1.5% w/v), a reaction accelerator (N,N,N’,N’-tetramethylethylenediamine, 2 vol%), and two co-monomers [2-(methacryloyloxy) ethyl trimethyl ammonium chloride (METAC, 2 vol%) and allylamine (1 vol%)]. METAC was added to increase the coil-toglobule transition temperature of poly(NIPAm), thereby facilitating homogeneous polymerization at room temperature. The allylamine adds amine groups to the network, which can subsequently be labeled with dyes after the formation of the microgel particles. The chemical formula [*] Dr. J. W. Kim, A. S. Utada, Dr. A. Fern ndez-Nieves, Prof. D. A. Weitz DEAS and Department of Physics Harvard University Cambridge, MA 02138 (USA) Fax: (+1)617-495-2875 E-mail: weitz@deas.harvard.edu

Microelectrode arrays: a physiologically based neurotoxicity testing platform for the 21st century.

Abstract: Microelectrode arrays (MEAs) have been in use over the past decade and a half to study multiple aspects of electrically excitable cells. In particular, MEAs have been applied to explore the pharmacological and toxicological effects of numerous compounds on spontaneous activity of neuronal and cardiac cell networks. The MEA system enables simultaneous extracellular recordings from multiple sites in the network in real time, increasing spatial resolution and thereby providing a robust measure of network activity. The simultaneous gathering of action potential and field potential data over long periods of time allows the monitoring of network functions that arise from the interaction of all cellular mechanisms responsible for spatio-temporal pattern generation. In these functional, dynamic systems, physical, chemical, and pharmacological perturbations are holistically reflected by the tissue responses. Such features make MEA technology well suited for the screening of compounds of interest, and also allow scaling to high throughput systems that can record from multiple, separate cell networks simultaneously in multi-well chips or plates. This article is designed to be useful to newcomers to this technology as well as those who are currently using MEAs in their research. It explains how MEA systems operate, summarizes what systems are available, and provides a discussion of emerging mathematical schemes that can be used for a rapid classification of drug or chemical effects. Current efforts that will expand this technology to an influential, high throughput, electrophysiological approach for reliable determinations of compound toxicity are also described and a comprehensive review of toxicological publications using MEAs is provided as an appendix to this publication. Overall, this article highlights the benefits and promise of MEA technology as a high throughput, rapid screening method for toxicity testing.