2,440 research outputs found

    Factors Affecting Perceived Satisfaction with a BPM Tool: A Student Perspective

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    Although Business Process Management (BPM) tools potentially enhance organizations’ productivity, dissatisfied users will hinder such outcomes. This pedagogical study is an innovative collaboration with a vendor to analyze factors affecting students\u27 perceived satisfaction with the vendor’s BPM tool. The analysis of students\u27 comments reveals issues with ease of use and documentation. Specifically, students remarked on difficulties with process modeling and simulation report generation. Feedback to the vendor may result in future modifications to the BPM tools. Implications for educational research include suggestions for teaching future BPM courses

    Identification of antigen-presenting dendritic cells in mouse aorta and cardiac valves

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    Presumptive dendritic cells (DCs) bearing the CD11c integrin and other markers have previously been identified in normal mouse and human aorta. We used CD11c promoter-enhanced yellow fluorescent protein (EYFP) transgenic mice to visualize aortic DCs and study their antigen-presenting capacity. Stellate EYFP + cells were readily identified in the aorta and could be double labeled with antibodies to CD11c and antigen-presenting major histo-compatability complex (MHC) II products. The DCs proved to be particularly abundant in the cardiac valves and aortic sinus. In all aortic locations, the CD11c + cells localized to the subintimal space with occasional processes probing the vascular lumen. Aortic DCs expressed little CD40 but expressed low levels of CD1d, CD80, and CD86. In studies of antigen presentation, DCs selected on the basis of EYFP expression or binding of anti-CD11c antibody were as effective as DCs similarly elected from the spleen. In particular, the aortic DCs could cross-present two different protein antigens on MHC class I to CD8 + TCR transgenic T cells. In addition, after intravenous injection, aortic DCs could capture anti-CD11c antibody and cross-present ovalbumin to T cells. These results indicate that bona fide DCs are a constituent of the normal aorta and cardiac valves

    Microbial stimulation fully differentiates monocytes to DC-SIGN/CD209 + dendritic cells for immune T cell areas

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    Dendritic cells (DCs), critical antigen-presenting cells for immune control, normally derive from bone marrow precursors distinct from monocytes. It is not yet established if the large reservoir of monocytes can develop into cells with critical features of DCs in vivo. We now show that fully differentiated monocyte-derived DCs (Mo-DCs) develop in mice and DC-SIGN/CD209a marks the cells. Mo-DCs are recruited from blood monocytes into lymph nodes by lipopolysaccharide and live or dead gram-negative bacteria. Mobilization requires TLR4 and its CD14 coreceptor and Trif. When tested for antigen-presenting function, Mo-DCs are as active as classical DCs, including cross-presentation of proteins and live gram-negative bacteria on MHC I in vivo. Fully differentiated Mo-DCs acquire DC morphology and localize to T cell areas via L-selectin and CCR7. Thus the blood monocyte reservoir becomes the dominant presenting cell in response to select microbes, yielding DC-SIGN + cells with critical functions of DCs

    Flt3 signaling-dependent dendritic cells protect against atherosclerosis

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    Early events in atherosclerosis occur in the aortic intima and involve monocytes that become macrophages. We looked for these cells in the steady state adult mouse aorta, and surprisingly, we found a dominance of dendritic cells (DCs) in the intima. In contrast to aortic adventitial macrophages, CD11c +MHC II hi DCs were poorly phagocytic but were immune stimulatory. DCs were of two types primarily: classical Flt3-Flt3L signaling-dependent, CD103 +CD11b - DCs and macrophage-colony stimulating factor (M-CSF)-dependent, CD14 +CD11b +DC-SIGN + monocyte-derived DCs. Both types expanded during atherosclerosis. By crossing Flt3 -/- to Ldlr -/- atherosclerosis-prone mice, we developed a selective and marked deficiency of classical CD103 + aortic DCs, and they were associated with exacerbated atherosclerosis without alterations in blood lipids. Concomitantly, the Flt3 -/-Ldlr -/- mice had fewer Foxp3 + Treg cells and increased inflammatory cytokine mRNAs in the aorta. Therefore, functional DCs are dominant in normal aortic intima and, in contrast to macrophages, CD103 + classical DCs are associated with atherosclerosis protection

    Study of vacancy ordering and the boson peak in metastable cubic Ge-Sb-Te using machine learning potentials

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    The mechanism of the vacancy ordering in metastable cubic Ge-Sb-Te (c-GST) that underlies the ultrafast phase-change dynamics and prominent thermoelectric properties remains elusive. Achieving a comprehensive understanding of the vacancy-ordering process at an atomic level is challenging because of enormous computational demands required to simulate disordered structures on large temporal and spatial scales. In this study, we investigate the vacancy ordering in c-GST by performing large-scale molecular dynamics simulations using machine learning potentials. The initial c-GST structure with randomly distributed vacancies rearranges to develop a semi-ordered cubic structure with layer-like ordered vacancies after annealing at 700~K for 100~ns. The vacancy ordering significantly affects the lattice dynamical properties of c-GST. In the initial structure with fully disordered vacancies, we observe a boson peak, usually associated with amorphous solids, that consists of localized modes at ∼\sim0.575~THz. As vacancies become ordered, the boson peak disappears and the Debye-Waller thermal \textit{B} factor of Te decreases substantially. This finding indicates that the c-GST undergoes a transition from amorphous-like to crystalline-like solid state by thermal annealing in low-frequency dynamics.Comment: 8 pages, 1 Table of Contents figure, 7 main figures, Supplemental Materia

    Non-Einstein Viscosity Phenomenon of Acrylonitrile–Butadiene–Styrene Composites Containing Lignin–Polycaprolactone Particulates Highly Dispersed by High-Shear Stress

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    Lignin powder was modified via ring-opening polymerization of caprolactone to form a lignin–polycaprolactone (LPCL) particulate. The LPCL particulates were mixed with an acrylonitrile–butadiene–styrene (ABS) matrix at an extremely high rotational speed of up to 3000 rpm, which was achieved by a closed-loop screw mixer and in-line melt extruder. Using this high-shear extruding mixer, the LPCL particulate size was controlled in the range of 3395 nm (conventional twin-screw extrusion) down to 638 nm (high-shear mixer of 3000 rpm) by altering the mixing speed and time. The resulting LPCL/ABS composites clearly showed non-Einstein viscosity phenomena, exhibiting reduced viscosity (2130 Pa·s) compared to the general extruded composite one (4270 Pa·s) at 1 s–1 and 210 °C. This is due to the conformational rearrangement and the increased free volume of ABS molecular chains in the vicinity of LPCL particulates. This was supported by the decreased glass transition temperature (Tg, 83.7 °C) of the LPCL/ABS composite specimens, for example, giving a 21.8% decrement compared to that (107 °C) of the neat ABS by the incorporation of 10 wt % LPCL particulates in ABS. The LPCL particulate morphology, damping characteristics, and light transmittance of the developed composites were thoroughly investigated at various levels of applied shear rates and mixing conditions. The non-Einstein rheological phenomena stemming from the incorporation of LPCL particulates suggest an interesting plasticization methodology: to improve the processability of high-loading filler/polymer composites and ultra-high molecular weight polymers that are difficult to process because of their high viscosity
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