755 research outputs found

    Dynamic heterodyne near field scattering

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    The technique heterodyne near field scattering (HNFS), originally developed for low-angle static light scattering, has also been implemented for carrying out dynamic light scattering. While the classical dynamic light scattering method measures the intensity-intensity correlation function, dynamic HNFS gives directly the field-field correlation function, without any assumption on the statistical properties of the sample, as the ones required by the Siegert relation. The technique has been tested with calibrated Brownian particles and its performances compared to those of the classical dynamic light scattering method.The technique heterodyne near field scattering (HNFS), originally developed for low-angle static light scattering, has also been implemented for carrying out dynamic light scattering. While the classical dynamic light scattering method measures the intensity-intensity correlation function, dynamic HNFS gives directly the field-field correlation function, without any assumption on the statistical properties of the sample, as the ones required by the Siegert relation. The technique has been tested with calibrated Brownian particles and its performances compared to those of the classical dynamic light scattering method. \ua9 2008 American Institute of Physics

    Heterodyne speckle velocimetryof Poiseuille flow

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    We review the technique named heterodyne speckle velocimetry and present two applications for testing the method with a fluid moving under the conditions of Poiseuille flow. The fluid was seeded with small tracking particles diameter 300 nm and fluxed between the two parallel planes of a cell with constant or variable cross section. In the first case the velocity distribution was constant along the direction parallel to the planes and was in excellent agreement with the expected Poiseuille profile along the orthogonal direction. In the second case, where velocity gradients were present also along the planes, the technique was able to reconstruct both the orthogonal Poiseuille profile and the in-plane two dimensional mapping of the velocity vectors, with the possibility of measuring the fluid flux within an accuracy of 1%

    Mild synthesis of poly(HEMA)-networks as well-defined nanoparticles in supercritical carbon dioxide

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    Free-radical dispersion polymerisation of 2-hydroxyethyl methacrylate was carried out in supercritical carbon dioxide (scCO2) in the presence of stabilisers based on polyethylene oxide (PEO) and poly(heptadecafluorodecyl acrylate) (PFDA). Different architectures of copolymers (random, palm-tree and diblock) were tested for their surface tension, cloud point and as a stabilising agent. The diblock architecture was found to be the best candidate resulting in poly(HEMA) spherical particles with a size of 316 nm. Furthermore, the effect of the CO2-phobic block (PEO) in the diblock architecture was investigated by using three different chain lengths (1000, 2000, 5000 g mol−1). By optimizing the stabiliser composition and structure, mild reaction conditions have been identified allowing us to obtain well-defined spherical cross-linked poly(HEMA) particles with a mean diameter of unprecedented low size (216 nm) at a temperature as low as 35 °C

    Comparison of dogs treated for primary immune-mediated hemolytic anemia in Tuscany, Italy and Texas, USA

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    This retrospective study compared clinical characteristics between dogs treated for IMHA by veterinary teaching hospitals in Tuscany, Italy and Texas, USA between 2010 and 2018

    Factors influencing the first thousand days of life

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    The first 1,000 days is a vulnerable phase in which parents, institutions and health professionals should create early interventions for the proper development and promotion of good health

    Probing Transverse Coherence with the Heterodyne Speckle Approach: Overview and Perspectives☆

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    Abstract The properties of spatial coherence of radiation emitted by relativistic electrons is far from being trivial. Assessing the coherence of high-brilliance X-ray sources (3rd generation synchrotrons or free electron lasers) is of crucial importance for machine diagnostics, as well as in planning experiments exploiting coherent techniques. The Heterodyne Speckles method, firstly described by Alaimo et al. (2009), is a valuable alternative to standard methods (e.g. Young's interferometer) which 1) provides a direct measure of transverse coherence without any a-priori assumption, 2) provides a full 2D map of coherence, 3) is capable of one shot, time-resolved measures, 4) is scalable over a wide range of wavelengths. It relies upon the statistical analysis of radiation scattered by spherical particles randomly distributed and suspended in a fluid. Here we give an overview of this method, from the theoretical framework to the operating conditions to be adopted in order to obtain coherence measurements in several conditions

    Cancer pain management in an oncological ward in a comprehensive cancer center with an established palliative care unit.

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    Abstract BACKGROUND: This survey was performed to draw information on pain prevalence, intensity, and management from a sample of patients who were admitted to an oncologic center where a palliative care unit (PCU) has been established for 13 years. METHODS: Cross-sectional survey in an oncological department performed 1 day per month for six consecutive months. RESULTS: Of the 385 patients, 69.1, 19.2, 8.6, and 3.1 % had no pain, mild, moderate, and severe pain, respectively. Inpatients and patients with a low Karnofsky score showed higher levels of pain intensity (p < 0.0005). One hundred twenty-eight patients with pain or receiving analgesics were analyzed for pain management index (PMI). Only a minority of patients had negative PMI score, which was statistically associated with inpatient admission (p = 0.011). Fifty of these 128 patients had breakthrough pain (BTP), and all of them were receiving some medication for BTP. CONCLUSION: It is likely that the presence of PCU team providing consultation, advices, and cultural pressure, other than offering admissions for difficult cases had a positive impact on the use of analgesics, as compared with previous similar surveys performed in oncological setting, where a PCU was unavailable. This information confirms the need of the presence of a PCU in a high volume oncological department
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