65 research outputs found

    Design considerations for low-voltage on-board DC/DC modules for next generations of data processing circuits

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    Analysis and evaluation of interleaving techniques in forward converters

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    Liquid-Liquid Flow in a Capillary Microreactor: Hydrodynamic Flow Patterns and Extraction Performance

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    The capillary microreactor, with four stable operating flow patterns and a throughput range from g/h to kg/h, presents an attractive alternative to chip-based and microstructured reactors for lab and pilot scale applications. In this paper the extraction of 2-butanol from toluene under different flow patterns in a water/toluene flow in long capillary microreactors is presented. The influence of the capillary length (0.2-2.2 m), flow rate (0.1-12 ml/min) and aqueous-to-organic volumetric flow ratio (0.25-9) on the slug, bubbly, parallel and annular flow hydrodynamics was investigated. Weber number dependant flow maps were composed for capillary lengths of 0.4 and 2 m, which are used to interpret the flow pattern formation in terms of surface tension and inertia forces. By decreasing the capillary length from 2 to 0.4 m, the transition of annular to parallel flow was observed. The capillary length had little influence on the slug and bubbly flows. The flow patterns were evaluated in terms of stability, surface-to-volume ratio, achieved throughput and extraction efficiency. Slug and bubbly flow operation yielded 100 % thermodynamic extraction efficiency, while by increasing the aqueous-to-organic volumetric ratio to 9 allowed for 99 % 2-butanol extraction. The parallel and annular flow operational windows were limited by the capillary length, thus yielding maximal 2-butanol extraction of 30 and 47 %, for the parallel and annular flow, respectively

    Enhancing MRI of prostate cancer using PSMA-targeting iron oxide magnetic nanoparticles

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    Introduction Novel imaging techniques for prostate cancer (PCa) are required to improve staging and real-time assessment of therapeutic response. We performed preclinical evaluation of newly-developed, biocompatible magnetic nanoparticles (MNPs) conjugated with J591, an antibody specific for prostate specific membrane antigen (PSMA), to enhance magnetic resonance imaging (MRI) of PCa. PSMA is expressed on ∼90% of PCa, including those that are castrate-resistant, rendering it as a rational target for PCa imaging. Materials and Methods The specificity of J591 for PSMA was confirmed by flow cytometric analysis of several PCa cell lines of known PSMA status. MNPs were prepared, engineered to the appropriate size, labeled with DiR fluorophore, and their toxicity to a panel of PC cells was assessed by in vitro Alamar Blue assay. Immunohistochemistry, fluorescence microscopy and Prussian Blue staining (iron uptake) were used to evaluate PSMA specificity of J591-MNP conjugates. In vivo MRI studies (16.4T MRI system) were performed using live immunodeficient mice bearing orthotopic LNCaP xenografts and injected intravenously with J591-MNPs or MNPs alone. Results MNPs were non-toxic to PCa cells. J591-MNP conjugates showed no compromise in specificity of binding to PSMA+ cells and showed enhanced iron uptake compared with MNPs alone. In vivo, tumour targeting (significant MR image contrast) was evident in mice injected with J591-MNPs, but not MNPs alone. Resected tumours from targeted mice had an accumulation of MNPs, not seen in normal control prostate. Conclusions Application of PSMA-targeting MNPs into conventional MRI has potential to enhance PCa detection and localization in real-time, improving patient management

    Air pollution, physical activity and health : A mapping review of the evidence

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    Highlights • Air pollution (AP) and physical activity (PA) are important health risk factors; • We reviewed current evidence of AP and PA interactions for health; • PA behaviour and health effects might be moderated by AP exposure; • Epidemiological studies provide mixed results on AP and PA interaction; • More research collaboration is needed to study AP and PA relations.Background Exposure to air pollution and physical inactivity are both significant risk factors for non-communicable diseases (NCDs). These risk factors are also linked so that the change in exposure in one will impact risks and benefits of the other. These links are well captured in the active transport (walking, cycling) health impact models, in which the increases in active transport leading to increased inhaled dose of air pollution. However, these links are more complex and go beyond the active transport research field. Hence, in this study, we aimed to summarize the empirical evidence on the links between air pollution and physical activity, and their combined effect on individual and population health. Objectives and methods We conducted a non-systematic mapping review of empirical and modelling evidence of the possible links between exposure to air pollution and physical activity published until Autumn 2019. We reviewed empirical evidence for the (i) impact of exposure to air pollution on physical activity behaviour, (ii) exposure to air pollution while engaged in physical activity and (iii) the short-term and (iv) long-term health effects of air pollution exposure on people engaged in physical activity. In addition, we reviewed (v) public health modelling studies that have quantified the combined effect of air pollution and physical activity. These broad research areas were identified through expert discussions, including two public events performed in health-related conferences. Results and discussion The current literature suggests that air pollution may decrease physical activity levels during high air pollution episodes or may prevent people from engaging in physical activity overall in highly polluted environments. Several studies have estimated fine particulate matter (PM2.5) exposure in active transport environment in Europe and North-America, but the concentration in other regions, places for physical activity and for other air pollutants are poorly understood. Observational epidemiological studies provide some evidence for a possible interaction between air pollution and physical activity for acute health outcomes, while results for long-term effects are mixed with several studies suggesting small diminishing health gains from physical activity due to exposure to air pollution for long-term outcomes. Public health modelling studies have estimated that in most situations benefits of physical activity outweigh the risks of air pollution, at least in the active transport environment. However, overall evidence on all examined links is weak for low- and middle-income countries, for sensitive subpopulations (children, elderly, pregnant women, people with pre-existing conditions), and for indoor air pollution. Conclusions Physical activity and air pollution are linked through multiple mechanisms, and these relations could have important implications for public health, especially in locations with high air pollution concentrations. Overall, this review calls for international collaboration between air pollution and physical activity research fields to strengthen the evidence base on the links between both and on how policy options could potentially reduce risks and maximise health benefits

    UV responses of <em>Lolium perenne</em> raised along a latitudinal gradient across Europe: A filtration study.

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    Lolium perenne (cv. AberDart) was grown at 14 locations along a latitudinal gradient across Europe (37-68&deg;N) to study the impact of ultraviolet radiation (UV) and climate on aboveground growth and foliar UV-B absorbing compounds. At each location, plants were grown outdoors for 5 weeks in a replicated UV-B filtration experiment consisting of open, UV-B transparent (cellulose diacetate) and UV-B opaque (polyester) environments. Fourier transform-infrared spectroscopy was used to compare plant metabolite profiles in relation to treatment and location. UV radiation and climatic parameters were determined for each location from online sources and the data were assessed using a combination of anova and multiple regression analyses. Most of the variation in growth between the locations was attributable to the combination of climatic parameters, with minimum temperature identified as an important growth constraint. However, no single environmental parameter could consistently account for the variability in plant growth. Concentrations of foliar UV-B absorbing compounds showed a positive trend with solar UV across the latitudinal gradient; however, this relationship was not consistent in all treatments. The most striking experimental outcome from this study was the effect of presence or absence of filtration frames on UV-absorbing compounds. Overall, the study demonstrates the value of an European approach in studying the impacts of natural UV across a large latitudinal gradient. We have shown the feasibility of coordinated UV filtration at multiple sites but have also highlighted the need for open controls and careful interpretation of plant responses

    Density of Liquid Ni-Ti and a New Optical Method for its Determination

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    Liquid Ni-Ti alloys were processed in a containerless way using the technique of electromagnetic levitation in order to determine their densities. An improved optical method was utilized where, in addition to recording shadowgraph images from the side, a second camera recorded images of the sample from the top. A correction factor for the density was calculated from the top-view images. This method yields measurements insensitive to droplet rotation and static deformation which removes the need to assume axial symmetry. The measured densities are discussed in terms of the molar volume. A negative molar excess volume was obtained, indicating that Ni-Ti is a highly non-ideal system. These measurements were then used to test a recently proposed relationship between the molar excess volume, the excess free energy, and the isothermal compressibility. For the first time, the excess volume of a binary alloy, i.e., Ni-Ti, is adequately predicted by a thermodynamic model
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