60 research outputs found

    Digital holography as 3D tracking tool for assessing acoustophoretic particle manipulation

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    The integration of digital holography (DH) imaging and the acoustic manipulation of micro-particles in a microfluidic environment is investigated. The ability of DH to provide efficient 3D tracking of particles inside a microfluidic channel is exploited to measure the position of multiple objects moving under the effect of stationary ultrasound pressure fields. The axial displacement provides a direct verification of the numerically computed positions of the standing wave’s node, while the particle’s transversal movement highlights the presence of nodes in the planar direction. Moreover, DH is used to follow the aggregation dynamics of trapped spheres in such nodes by using aggregation rate metrics

    Rapid prototyping of plastic lab-on-a-chip by femtosecond laser micromachining and removable insert microinjection molding

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    We have introduced a new hybrid fabrication method for lab-on-a-chip devices through the combination of femtosecond laser micromachining and removable insert micro-injection molding. This method is particularly suited for the fast prototyping of new devices, while maintaining a competitive low cost. To demonstrate the effectiveness of our approach, we designed, fabricated, and tested a completely integrated flow cytometer coupled to a portable media device. The system operation was tested with fluorescent plastic micro-bead solutions ranging from 100 beads/?L to 500 beads/?L. We demonstrated that this hybrid lab-on-a-chip fabrication technology is suitable for producing low-cost and portable biological microsystems and for effectively bridging the gap between new device concepts and their mass production

    Clinical and Socio-Demographic Determinants of Self-Care Behaviours in Patients with Heart Failure and Diabetes Mellitus: A Multicentre Cross-Sectional Study

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    Background Self-care is vital for patients with heart failure to maintain health and quality of life, and it is even more vital for those who are also affected by diabetes mellitus, since they are at higher risk of worse outcomes. The literature is unclear on the influence of diabetes on heart failure self-care as well as on the influence of socio-demographic and clinical factors on self-care. Objectives (1) To compare self-care maintenance, self-care management and self-care confidence of patients with heart failure and diabetes versus those heart failure patients without diabetes; (2) to estimate if the presence of diabetes influences self-care maintenance, self-care management and self-care confidence of heart failure patients; (3) to identify socio-demographic and clinical determinants of self-care maintenance, self-care management and self-care confidence in patients with heart failure and diabetes. Design Secondary analysis of data from a multicentre cross-sectional study. Setting Outpatient clinics from 29 Italian provinces. Participants 1192 adults with confirmed diagnosis of heart failure. Methods Socio-demographic and clinical data were abstracted from patients’ medical records. Self-care maintenance, self-care management and self-care confidence were measured with the Self-Care of Heart Failure Index Version 6.2; each scale has a standardized score from 0 to 100, where a score \u3c70 indicates inadequate self-care. Multiple linear regression analyses were performed. Results Of 1192 heart failure patients, 379 (31.8%) had diabetes. In these 379, heart failure self-care behaviours were suboptimal (means range from 53.2 to 55.6). No statistically significant differences were found in any of the three self-care measures in heart failure patients with and without diabetes. The presence of diabetes did not influence self-care maintenance (p = 0.12), self-care management (p = 0.21) or self-care confidence (p = 0.51). Age (p = 0.04), number of medications (p = 0.01), presence of a caregiver (p = 0.04), family income (p = 0.009) and self-care confidence (p \u3c 0.001) were determinants of self-care maintenance. Gender (p = 0.01), number of medications (p = 0.004) and self-care confidence (p \u3c 0.001) were significant determinants of self-care management. Number of medications (p = 0.002) and cognitive function (p \u3c 0.001) were determinants of self-care confidence. Conclusions Self-care was poor in heart failure patients with diabetes mellitus. This population needs more intensive interventions to improve self-care. Determinants of self-care in heart failure patients with diabetes mellitus should be systematically assessed by clinicians to identify patients at risk of inadequate self-care

    Tunable two-dimensional hexagonal phase array in domain-engineered z-cut lithium niobate crystal

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    An optical phase array with tunable phase step is demonstrated. The phase array consists of a 2-dimensional hexagonal lattice of inverted ferroelectric domains fabricated on a z-cut lithium niobate substrate. The electro-optically tunable phase step is obtained by the application of an external electric field along the z axis of the crystal via transparent electrodes. Theoretical analysis and experimental results are presented showing that a tunable and flexible adaptive optical illuminator device can be realized by combining the electro-optic tunability with the Talbot effect. Generation of a multiplicity of light pattern is shown

    An Implantable Vascularized Protein Gel Construct That Supports Human Fetal Hepatoblast Survival and Infection by Hepatitis C Virus in Mice

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    Widely accessible small animal models suitable for the study of hepatitis C virus (HCV) in vivo are lacking, primarily because rodent hepatocytes cannot be productively infected and because human hepatocytes are not easily engrafted in immunodeficient mice.We report here on a novel approach for human hepatocyte engraftment that involves subcutaneous implantation of primary human fetal hepatoblasts (HFH) within a vascularized rat collagen type I/human fibronectin (rCI/hFN) gel containing Bcl-2-transduced human umbilical vein endothelial cells (Bcl-2-HUVEC) in severe combined immunodeficient X beige (SCID/bg) mice. Maturing hepatic epithelial cells in HFH/Bcl-2-HUVEC co-implants displayed endocytotic activity at the basolateral surface, canalicular microvilli and apical tight junctions between adjacent cells assessed by transmission electron microscopy. Some primary HFH, but not Huh-7.5 hepatoma cells, appeared to differentiate towards a cholangiocyte lineage within the gels, based on histological appearance and cytokeratin 7 (CK7) mRNA and protein expression. Levels of human albumin and hepatic nuclear factor 4alpha (HNF4alpha) mRNA expression in gel implants and plasma human albumin levels in mice engrafted with HFH and Bcl-2-HUVEC were somewhat enhanced by including murine liver-like basement membrane (mLBM) components and/or hepatocyte growth factor (HGF)-HUVEC within the gel matrix. Following ex vivo viral adsorption, both HFH/Bcl-2-HUVEC and Huh-7.5/Bcl-2-HUVEC co-implants sustained HCV Jc1 infection for at least 2 weeks in vivo, based on qRT-PCR and immunoelectron microscopic (IEM) analyses of gel tissue.The system described here thus provides the basis for a simple and robust small animal model of HFH engraftment that is applicable to the study of HCV infections in vivo

    An Ru-based catalytic membrane reactor for dry reforming of methane : its catalytic performance compared with tubular packed bed reactors

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    The methane reforming with CO2 seems to be a promising reaction system useful to reduce the greenhouse contribution of both gases into the atmosphere. On this basis, and considering the potentiality of this reaction system, the dry reforming reaction has been carried out in an Ru-based ceramic tubular membrane reactor, in which two Ru depositions have been performed using the co-condensation technique. Experimental results in terms of CH4 and CO2 conversion versus temperature during time are presented, as well as product selectivity and carbon deposition. These experiments have also been carried out using a traditional reactor. A comparison with literature data regarding dry reforming reaction is also provided. Experimental evidence points out a good catalyst activity for the methane dry reforming reaction, confirming the potentiality of a catalytic membrane applied to the reaction system. © 2003 Elsevier B.V. All rights reserved. 10.1016/S0920-5861(03)00202-

    Light-Induced Dynamic Holography

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    Holographic photomobile polymers (H-PMP) are a novel class of photomobile materials in which holograms can be optically recorded. They can be used in a large variety of applications, including optical switches and color selectors. In this work, we show one of the most important properties of the photomobile film, which is the photophobicity of the unpolymerized parts of the photomobile mixture. In order to investigate this property, we recorded a transmission phase grating on an H-PMP film, and used a different experimental technique to measure the diffraction efficiency, surface tension, and mixture properties. The results allowed for a better understanding of the mechanism of the light-controlled bending observed in these compounds

    Partial oxidation of methane in a catalytic ruthenium membrane reactor

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    A catalytic ruthenium membrane reactor (CRMR) is analyzed with regard to the methane partial oxidation reaction for synthesis gas production. The catalytic membrane consists of a commercial ceramic tube, where two different layers of ruthenium nanoparticles have been deposited on the inner surface. The metal deposition was performed by decomposition of a Ru complex under mild conditions. Different operating modes are analyzed for CRMR to establish the potentiality of the Ru catalyst deposited on the tubular ceramic support. A comparison in terms of methane conversion at various temperatures is presented. Experimental runs of CRMR containing a one-Ru-layer membrane and a two-Ru-layer membrane have also been compared
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