8,268 research outputs found

    Flow optimization study of a batch microfluidics PET tracer synthesizing device.

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    We present numerical modeling and experimental studies of flow optimization inside a batch microfluidic micro-reactor used for synthesis of human-scale doses of Positron Emission Tomography (PET) tracers. Novel techniques are used for mixing within, and eluting liquid out of, the coin-shaped reaction chamber. Numerical solutions of the general incompressible Navier Stokes equations along with time-dependent elution scalar field equation for the three dimensional coin-shaped geometry were obtained and validated using fluorescence imaging analysis techniques. Utilizing the approach presented in this work, we were able to identify optimized geometrical and operational conditions for the micro-reactor in the absence of radioactive material commonly used in PET related tracer production platforms as well as evaluate the designed and fabricated micro-reactor using numerical and experimental validations

    Persistence Influence for IT Outsourcing: Small and Medium Firms Perspectives of Their Application Service Providers

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    Given today’s fierce competition among application service providers (ASP), one key question for any ASP is how to retain their customers’ loyalty through partnership establishment and provision of quality of service. However, prior studies focused on the ongoing relationships between the ASP and clients are sparse. This study investigates the perspectives of small and medium firms for their information technology (IT) outsourcing, especially when they are seeking facilitation from the ASP. The study applies the psychological concepts of satisfaction and trust to assess a firm’s loyalty state which can predict the persistence for IT outsourcing. The research questions are: (i) Do the key factors of IT outsourcing enhancement - partnership and quality of service - influence a firm’s IT outsourcing cognition? (ii) Does a small or medium firm’s IT outsourcing cognition - satisfaction and trust - have a positive relationship to its IT outsourcing continuance with an ASP? This study uses the partial least squares approach to develop and test a model that encapsulates these questions. A field study of 158 small and medium firms was conducted. Results show that the key factors of IT outsourcing enhancement and cognition are able to predict a firm’s persistence of IT outsourcing

    Fully Mediated Effects of Formative Measures Using MIMIC Constructs

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    Formatively-measured constructs are increasingly applied in information system research models.Recent work shows that exogenous formatively-measured constructs suffer from a number of problems that include interpretational confounding and a lack of external consistency. Yet replacement by reflectively-measured constructs can lead to bias if not theoretically appropriate. One solution may be to use a MIMIC construct composed of the formative measures as well as two additional reflective measures. A simulation study indicates that a MIMIC so composed mitigates the problems of interpretational confounding and poor external consistency allowing use broader use in a variety of structural models. Available at: https://aisel.aisnet.org/pajais/vol4/iss2/2

    Expression of hepatocyte growth factor-like protein in human wound tissue and its biological functionality in human keratinocytes

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    Hepatocyte growth factor-like protein (HGFl) and its receptor, Recepteur d'Origine Nantais (RON), have been implicated in the development of wound chronicity. HGFl and RON expression was detected in acute wound tissue, chronic wound tissue and in normal skin using quantitative polymerase chain reaction (Q-PCR). HGFl and RON expression was also assessed in chronic healing and chronic non-healing wound tissues using Q-PCR and immunohistochemical staining. Expression was similarly detected in the HaCaT immortalized human keratinocyte cell line using reverse transcription polymerase chain reaction (RT-PCR). rhHGFl was used to assess the impact of this molecule on HaCaT cell functionality using in vitro growth assays and electric cell-substrate impendence sensing (ECIS) migration assays. HGFl and RON transcript expression were significantly increased in acute wound tissue compared to chronic wound tissue and were also elevated, though non-significantly, in comparison to normal skin. Minimal expression was seen in both healing and non-healing chronic wounds. Treatment of HaCaT cells with rhHGFl had no effect on growth rates but did enhance cell migration. This effect was abolished by the addition of a phospholipase C gamma (PLCγ) small molecule inhibitor. The increased expression of HGFl and RON in acute, healing wounds and the pro-migratory effect of HGFl in an in vitro human keratinocyte model, may indicate a role for HGFl in active wound healing

    Water pollutant fingerprinting tracks recent industrial transfer from coastal to inland China: a case study

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    In recent years, China’s developed regions have transferred industries to undeveloped regions. Large numbers of unlicensed or unregistered enterprises are widespread in these undeveloped regions and they are subject to minimal regulation. Current methods for tracing industrial transfers in these areas, based on enterprise registration information or economic surveys, do not work. The authors have developed an analytical framework combining water fingerprinting and evolutionary analysis to trace the pollution transfer features between water sources. We collected samples in Eastern China (industrial export) and Central China (industrial acceptance) separately from two water systems. Based on the water pollutant fingerprints and evolutionary trees, we traced the pollution transfer associated with industrial transfer between the two areas. The results are consistent with four episodes of industrial transfers over the past decade. The results also show likely types of the transferred industries - electronics, plastics, and biomedicines - that contribute to the water pollution transfer

    Development of a Highway Safety Management System for Indiana: Phase 1

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    This report presents the work plan for the development of a highway safety management system for Indiana. It identifies major activities and responsibilities for the development and implementation of a formal, statewide, interactive safety decision-making process. The safety management system of Indiana is perceived as a continuous process of considering all opportunities to improve highway safety in all phases of highway planning, design, construction, maintenance and operation. The primary emphasis is on coordination of activities at various levels and on the development of a common information data base that can be used for selecting and implementing effective highway safety strategies and projects

    Communication: Diverse nanoscale cluster dynamics: Diffusion of 2D epitaxial clusters

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    The dynamics of nanoscale clusters can be distinct from macroscale behavior described by continuum formalisms. For diffusion of 2D clusters of N atoms in homoepitaxial systems mediated by edge atom hopping, macroscale theory predicts simple monotonic size scaling of the diffusion coefficient, DN ∼ N−β, with β = 3/2. However, modeling for nanoclusters on metal(100) surfaces reveals that slow nucleation-mediated diffusion displaying weak size scaling β \u3c 1 occurs for “perfect” sizes Np = L2 and L(L+1) for integer L = 3,4,… (with unique square or near-square ground state shapes), and also for Np+3, Np+4,…. In contrast, fast facile nucleation-free diffusion displaying strong size scaling β ≈ 2.5 occurs for sizes Np+1 and Np+2. DN versus N oscillates strongly between the slowest branch (for Np+3) and the fastest branch (for Np+1). All branches merge for N = O(102), but macroscale behavior is only achieved for much larger N = O(103). This analysis reveals the unprecedented diversity of behavior on the nanoscale
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