1,226 research outputs found

    Experiments on identification and control of inflow disturbances in contracting streams

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    Vorticity from all surfaces and isolated objects in the vicinity of the fan intake, including the outside surfaces of the fan housing, were identified as the major sources for disturbances leading to blade passing frequency noise. The previously proposed mechanism based on atmospheric turbulence is refuted. Flow visualization and hot wire techniques were used in three different facilities to document the evolution of various types of disturbances, including the details of the mean flow and turbulence characteristics. The results suggest that special attention must be devoted to the design of the inlet and that geometric modeling may not lead to adequate simulation of the in flight characteristics. While honeycomb type flow manipulators appear to be effective in reducing some of the disturbances, higher pressure drop devices that generate adequate turbulence, for mixing of isolated nonuniformities, may be necessary to suppress the remaining disturbances. The results are also applicable to the design of inlets of open return wind tunnels and similar flow facilities

    Effect of substrate thermal resistance on space-domain microchannel

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    In recent years, Fluorescent Melting Curve Analysis (FMCA) has become an almost ubiquitous feature of commercial quantitative PCR (qPCR) thermal cyclers. Here a micro-fluidic device is presented capable of performing FMCA within a microchannel. The device consists of modular thermally conductive blocks which can sandwich a microfluidic substrate. Opposing ends of the blocks are held at differing temperatures and a linear thermal gradient is generated along the microfluidic channel. Fluorescent measurements taken from a sample as it passes along the micro-fluidic channel permits fluorescent melting curves to be generated. In this study we measure DNA melting temperature from two plasmid fragments. The effects of flow velocity and ramp-rate are investigated, and measured melting curves are compared to those acquired from a commercially available PCR thermocycler

    Gas chromatography of indium in macroscopic and carrier-free amounts using quartz and gold as stationary phases

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    The chemical investigation of E113 is likely to become soon feasible. The determination of chemical properties of carrier-free amounts of the lighter homologues of element 113, especially indium and thallium, allows designing experimental set-ups and selecting experimental conditions suitable for performing these studies. Here, we present investigations of the interaction of indium species with quartz and gold surfaces. Deposition temperatures as well as enthalpies of adsorption were determined for indium Tdep=739±20°C (−ΔHads(In)=227±10kJ mol−1) and for indium hydroxide Tdep=250±20°C (−ΔHads(InOH)= 124±10kJ mol−1) respectively, on quartz. In case of adsorption of indium on a gold surface only a lower limit of the deposition temperature was established Tdep>980°C (−ΔHads(In)≥315±10kJ mol−1). Investigations of macroscopic amounts of indium in thermosublimation experiments at similar experimental conditions were instrumental to establish a tentative speciation of the observed indium specie

    Performance of a Novel Handheld Bioelectrical Impedance Device for Assessing Muscle Mass in Older Inpatients.

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    OBJECTIVES To investigate practicality and repeatability of a handheld compared to a state-of-the-art multisegmental bioelectrical impedance analysis (BIA) device to facilitate screening of sarcopenia in older inpatients. DESIGN AND SETTING Cross-sectional study in a geriatric rehabilitation hospital. PARTICIPANTS 207 inpatients aged 70+. MEASUREMENTS In a first phase, appendicular skeletal muscle mass index (ASMI) was measured using the handheld Biody xpertZm II BIA device (n=100). In a second phase, ASMI was obtained using the multisegmental Biacorpus RX 4004M device (n=107). Repeatability of BIA devices was compared in subgroups of patients (handheld BIA device: n=36, multisegmental BIA device: n=46) by intra-class correlation (ICC) and Bland-Altman plots. RESULTS Overall, measurement failure was seen in 31 patients (31%) tested with the handheld BIA device compared to one patient (0.9%) using the multisegmental BIA device (p<0.001). Main reasons for measurement failure were inability of patients to adopt the position necessary to use the handheld BIA device and device failure. The mean difference of two ASMI measurements in the same patient was 0.32 (sd 0.85) using the handheld BIA device compared to 0.02 kg/m2 (sd 0.07) using the multisegmental device (adjusted mean difference between both groups -0.35, 95% confidence interval (CI) -0.61 to -0.09 kg/m2). Congruently, Bland-Altman plots showed poor agreement with the handheld compared to the multisegmental BIA device. CONCLUSION The handheld BIA device is neither a practical nor reliable device for assessing muscle mass in older rehabilitation inpatients

    Actividad de glutation peroxidasa (GSH-Px) en sangre de bovinos a pastoreo de la IX Región, Chile y su relación con la concentración de selenio en el forraje

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    Con el objeto de determinar la actividad sanguínea de glutatión peroxidasa (GSH-Px; E.C. 1.11.1.9) en bovinos lecheros de la IX Región de la Araucanía (38º LS y 71º LO), Chile, y establecer su eventual asociación con el contenido de Se en el forraje, durante el otoño y la primavera de 1999 se tomaron muestras de forraje de las praderas y de sangre en grupos de vacas en inicio de lactancia y vaquillas en 12 predios lecheros. Se midió la concentración de Se en el forraje empleando la técnica de espectroscopía de plasma acoplado inductivamente con detector de masas (ICP-MS) y la actividad sanguínea de GSH-Px mediante una técnica cinética compuesta NADPH-dependiente. La concentración de Se del forraje fue 0.03±0.02 ppm, donde un 83% presentó valores deficitarios (0.05). Se encontró un 20% de los grupos analizados con valores deficitarios (0.05). Heifers showed a lower activity for GSH-Px than cows in both periods (p<0.05). Twenty percent of the animals showed a low activity of GSH-Px (below 60 U/g Hb), meaning a Se deficiency in the animals. There was a relation between the content of Se in forage and the blood activity of GSH-Px in heifers (r= 0.74; p<0.05). Accordingly, the content of Se in most of the forage produced in the dairy cattle area from the IXth Region, Chile is below the nutritional requirements for grazing dairy cattle and nutritional metabolic deficiencies of Se are present in dairy herds according to blood activity of GSH-Px. Heifers are mostly affecte

    Adsorption interaction of carrier-free thallium species with gold and quartz surfaces

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    The adsorption interactions of thallium and its compounds with gold and quartz surfaces were investigated. Carrier-free amounts of thallium were produced in nuclear fusion reactions of alpha particles with thick gold targets. The method chosen for the studies was gas thermochromatography and varying the redox potential of the carrier gases. It was observed that thallium is extremely sensitive to trace amounts of oxygen and water, and can even be oxidized by the hydroxyl groups located on the quartz surface. The experiments on aquartz surface with O2, He, H2 gas in addition with water revealed the formation and deposition of only one thallium species - TlOH. The adsorption enthalpy was determined to be Δ HSiO2ads(TlOH) = −134±5kJ mol−1. Aseries of experiments using gold as stationary surface and different carrier gases resulted in the detection of two thallium species - metallic Tl (H2 as carrier gas) and TlOH (O2, O2+H2O and H2+H2O as pure carrier gas or carrier gas mixture) with Δ HAuads(Tl) = −270±10kJ mol− and Δ HAuads(TlOH) = −146±3kJ mol−1. These data demonstrate a weak interaction of TlOH with both quartz and gold surfaces. The data represent important information for the design of future experiments with the heavier homologue of Tl in group 13 of the periodic table - element 113 (E113

    The thermal release of scandium from titanium metal - a simple way to produce pure 44Sc for PET application

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    The radionuclide-generator based access to radiopharmaceutical isotopes represents a valuable alternative to directly produced isotopes at particle accelerators or nuclear reactors. The 44Ti based generator is of increasing interest for the delivery of PET-radiopharmaceutical isotopes used for imaging. The product of this generator 44Sc represents with its 3.97h half-life and 94.3% positron branching[1] a very promising candidate for labeling PET radiopharmaceuticals. The long half-life of 58.9±0.3y[2] of the 44Ti assures a constant and long lasting production of the daughter nuclide. Here we present a gas phase separation method of scandium from titanium via thermal release in vacuum. Titanium foils were irradiated with 40Ar to produce scandium in multi-nucleon transfer reactions. Another production reaction used was the irradiation of titanium by neutrons from the SINQ neutron source at the Paul Scherrer Institute (PSI). The titanium metal foils containing 44mSc and 46Sc were heated up for time periods of 15 and 60min to temperatures between 900°C and 1500°C in vacuum. Thus, release properties of scandium from titanium under these conditions were studied. The released scandium was collected on tantalum foils and could be rinsed of with concentrated nitric acid resulting in carrier free scandium nitrate solutions. From the experimental results optimum release conditions are suggeste

    Ability of 3 Frailty Measures to Predict Short-Term Outcomes in Older Patients Admitted for Post-Acute Inpatient Rehabilitation.

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    OBJECTIVES To evaluate the ability of 3 commonly used frailty measures to predict short-term clinical outcomes in older patients admitted for post-acute inpatient rehabilitation. DESIGN Observational cohort study. SETTING AND PARTICIPANTS Consecutive patients (n = 207) admitted to a geriatric inpatient rehabilitation facility. METHODS Frailty on admission was assessed using a frailty index, the physical frailty phenotype, and the Clinical Frailty Scale (CFS). Predictive capacity of the frailty instruments was analyzed for (1) nonhome discharge, (2) readmission to acute care, (3) functional decline, and (4) prolonged length of stay, using multivariate logistic regression models and receiver operating characteristic (ROC) curves. RESULTS The number of patients classified as frail was 91 (44.0%) with the frailty index, 134 (64.7%) using the frailty phenotype, and 151 (73.0%) with the CFS. The 3 frailty measures revealed acceptable discriminatory accuracy for nonhome discharge (area under the curve ≥ 0.7) but differed in their predictive ability: the adjusted odds ratio (OR) for nonhome discharge was highest for the CFS [6.2, 95% confidence interval (CI) 1.8-21.1], compared to the frailty index (4.1, 95% CI 2.0-8.4) and the frailty phenotype (OR 2.9, 95% CI 1.2-6.6). For the other outcomes, discriminatory accuracy based on ROC tended to be lower and predictive ability varied according to frailty measure. Readmission to acute care from inpatient rehabilitation was predicted by all instruments, most pronounced by the frailty phenotype (OR 5.4, 95% CI 1.6-18.8) and the frailty index (OR 2.5, 95% CI 1.1-5.6), and less so by the CFS (OR 1.4, 95% CI 0.5-3.8). CONCLUSIONS AND IMPLICATIONS Frailty measures may contribute to improved prediction of outcomes in geriatric inpatient rehabilitation. The choice of the instrument may depend on the individual outcome of interest and the corresponding discriminatory ability of the frailty measure

    Ascorbic acid (Vitamin C) content of tomatoes and apples

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    Report on Department of Horticulture Research Project No. 212, entitled, 'Conservation of nutritive value of foods'--P. [2].Digitized 2007 AES.Includes bibliographical references (pages 21-24)
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