1,394 research outputs found

    An analysis for the sound field produced by rigid wide cord dual rotation propellers of high solidarity in compressible flow

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    An unsteady lifting service theory for the counter-rotating propeller is presented using the linearized governing equations for the acceleration potential and representing the blades by a surface distribution of pulsating acoustic dipoles distributed according to a modified Birnbaum series. The Birnbaum series coefficients are determined by satisfying the surface tangency boundary conditions on the front and rear propeller blades. Expressions for the combined acoustic resonance modes of the front prop, the rear prop and the combination are also given

    Effect of extraction methods on physicochemical, nutritional, antinutritional, antioxidant and antimicrobial activity of Moringa (Moringa oleifera Lam.) seed kernel oil

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    The effect of three different extraction methods, namely supercritical CO2, soxhlet and solvent methods on the yield, efficiency, physico-chemical properties, nutritional, anti-nutritional composition, antimicrobial and antioxidant activities of moringa (Moringa oleifera Lam.) seed kernel oil was investigated in this study. Oil extraction for SC-CO2 were 37.76 g/100g and 98.43%, observed to be higher than those of soxhlet extraction (29.12 g/100g and 76.29%), and significantly lower than solvent extraction (22.12 g/100g and 57.99%). The physico-chemical composition of the oils showed considerable variation among the extraction methods. The SC-CO2 extracted oil was found to be of superior quality, showing negligible thermal degradation and exhibited significantly (p<0.01) higher nutritional and antioxidant activity and lower anti-nutritional composition than the soxhlet and solvent extracted oils. Oils produced by SC-CO2 and soxhlet extraction methods had antimicrobial activities higher than solvent extracted oil. SCCO2 extracted oil was found to have maximum number of bioactive compounds (14 compounds) followed by solvent (8 compounds) and soxhlet (4 compounds) extracted oil. The results of the study demonstrated that SC-CO2 would be a promising process for the extraction of moringa seed kernel oil of premium quality

    Raman Spectroscopy Provides a Powerful Diagnostic Tool for Accurate Determination of Albumin Glycation

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    We present the first demonstration of glycated albumin detection and quantification using Raman spectroscopy without the addition of reagents. Glycated albumin is an important marker for monitoring the long-term glycemic history of diabetics, especially as its concentrations, in contrast to glycated hemoglobin levels, are unaffected by changes in erythrocyte life times. Clinically, glycated albumin concentrations show a strong correlation with the development of serious diabetes complications including nephropathy and retinopathy. In this article, we propose and evaluate the efficacy of Raman spectroscopy for determination of this important analyte. By utilizing the pre-concentration obtained through drop-coating deposition, we show that glycation of albumin leads to subtle, but consistent, changes in vibrational features, which with the help of multivariate classification techniques can be used to discriminate glycated albumin from the unglycated variant with 100% accuracy. Moreover, we demonstrate that the calibration model developed on the glycated albumin spectral dataset shows high predictive power, even at substantially lower concentrations than those typically encountered in clinical practice. In fact, the limit of detection for glycated albumin measurements is calculated to be approximately four times lower than its minimum physiological concentration. Importantly, in relation to the existing detection methods for glycated albumin, the proposed method is also completely reagent-free, requires barely any sample preparation and has the potential for simultaneous determination of glycated hemoglobin levels as well. Given these key advantages, we believe that the proposed approach can provide a uniquely powerful tool for quantification of glycation status of proteins in biopharmaceutical development as well as for glycemic marker determination in routine clinical diagnostics in the future.National Center for Research Resources (U.S.) (Grant No. P41-RR02594)Massachusetts Institute of Technology. Laser Biomedical Research Cente

    Intra-aortic balloon counterpulsation in US and non-US centres: results of the Benchmark® Registry

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    Aims To examine differences in patient characteristics and outcomes in 19 636 patients enrolled in the USA and 3027 patients enrolled in other countries undergoing intra-aortic balloon pump (IABP) counterpulsation. Methods and results Indications for IABP use; a larger percentage of US patients were identified as ‘early support and stabilization for angiography or angioplasty' (21.1% US vs 11.8% non-US), and ‘pre-operative support for high-risk CABG' (15.9% vs 6.6%). A smaller percentage of US patients vs non-US patients were identified as ‘weaning from cardiopulmonary bypass' (14.3% vs 28.2%), and ‘refractory ventricular failure' (6.2% vs 9.8%). One out of five patients in both groups was listed as ‘cardiogenic shock' (18.9% US vs 20.2% non-US). All cause, risk-adjusted, in-hospital mortality (20.1% vs 28.7%; P<0.001), and mortality with IABP in place (10.8% vs 18.0%; P<0.001) were lower at US vs non-US sites. In both US and non-US institutions, IABP associated complication rates, such as IABP-related mortality (0.05% vs 0.07%), major limb ischaemia (0.9% vs 0.8%), and severe bleeding (0.9% vs 0.8%), were low. Conclusions IABP counterpulsation is deployed at an earlier clinical stage in US patients. Mortality rates are higher for non-US patients, particularly for patients with non-surgery cardiac interventions, even after adjusting for risk factors. Complication rates were low. Physicians should therefore not be reluctant to use IABP in high-risk patients undergoing cardiac procedure

    Identification of manganese superoxide dismutase from Sphingobacterium sp. T2 as a novel bacterial enzyme for lignin oxidation

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    The valorisation of aromatic heteropolymer lignin is an important unsolved problem in the development of a biomass-based biorefinery, for which novel high-activity biocatalysts are needed. Sequencing of the genomic DNA of lignin-degrading bacterial strain Sphingobacterium sp. T2 revealed no matches to known lignin-degrading genes. Proteomic matches for two manganese superoxide dismutase proteins were found in partially purified extracellular fractions. Recombinant MnSOD1 and MnSOD2 were both found to show high activity for oxidation of Organosolv and Kraft lignin, and lignin model compounds, generating multiple oxidation products. Structure determination revealed that the products result from aryl-Cα and Cα-Cβ bond oxidative cleavage and O-demethylation. The crystal structure of MnSOD1 was determined to 1.35 Å resolution, revealing a typical MnSOD homodimer harbouring a 5-coordinate trigonal bipyramidal Mn(II) centre ligated by three His, one Asp and a water/hydroxide in each active site. We propose that the lignin oxidation reactivity of these enzymes is due to the production of hydroxyl radical, a highly reactive oxidant. This is the first demonstration that MnSOD is a microbial lignin-oxidising enzyme

    Implementation of Basal-Bolus Therapy in Type 2 Diabetes:A Randomized Controlled Trial Comparing Bolus Insulin Delivery Using an Insulin Patch with an Insulin Pen

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    Background: Barriers to mealtime insulin include complexity, fear of injections, and lifestyle interference. This multicenter, randomized controlled trial evaluated efficacy, safety, and self-reported outcomes in adults with type 2 diabetes, inadequately controlled on basal insulin, initiating and managing mealtime insulin with a wearable patch versus an insulin pen. Methods: Adults with type 2 diabetes (n = 278, age: 59.2 +/- 8.9 years), were randomized to patch (n = 139) versus pen (n = 139) for 48 weeks, with crossover at week 44. Baseline insulin was divided 1:1 basal: bolus. Using a pattern-control logbook, subjects adjusted basal and bolus insulin weekly using fasting and premeal glucose targets. Results: Glycated hemoglobin (HbA1c) change (least squares mean +/- standard error) from baseline to week 24 (primary endpoint) improved (P \u3c 0.0001) in both arms, -1.7% +/- 0.1% and -1.6% +/- 0.1% for patch and pen (-18.6 +/- 1.1 and -17.5 +/- 1.1 mmol/mol), and was maintained at 44 weeks. The coefficient of variation of 7-point self-monitoring blood glucose decreased more (P = 0.02) from baseline to week 44 for patch versus pen. There were no differences in adverse events, including hypoglycemia (three severe episodes per arm), and changes in weight and insulin doses. Subject-reported treatment satisfaction, quality of life, experience ratings at week 24, and device preferences at week 48 significantly favored the patch. Most health care providers preferred patch for mealtime insulin. Conclusions: Bolus insulin delivered by patch and pen using an algorithm-based weekly insulin dose titration significantly improved HbA1c in adults with type 2 diabetes, with improved subject and health care provider experience and preference for the patch

    Harmonic Sums and Mellin Transforms up to two-loop Order

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    A systematic study is performed on the finite harmonic sums up to level four. These sums form the general basis for the Mellin transforms of all individual functions fi(x)f_i(x) of the momentum fraction xx emerging in the quantities of massless QED and QCD up to two--loop order, as the unpolarized and polarized splitting functions, coefficient functions, and hard scattering cross sections for space and time-like momentum transfer. The finite harmonic sums are calculated explicitly in the linear representation. Algebraic relations connecting these sums are derived to obtain representations based on a reduced set of basic functions. The Mellin transforms of all the corresponding Nielsen functions are calculated.Comment: 44 pages Latex, contract number adde

    A graphene-based physiometer array for the analysis of single biological cells

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    A significant advantage of a graphene biosensor is that it inherently represents a continuum of independent and aligned sensor-units. We demonstrate a nanoscale version of a micro-physiometer – a device that measures cellular metabolic activity from the local acidification rate. Graphene functions as a matrix of independent pH sensors enabling subcellular detection of proton excretion. Raman spectroscopy shows that aqueous protons p-dope graphene – in agreement with established doping trajectories, and that graphene displays two distinct pKa values (2.9 and 14.2), corresponding to dopants physi- and chemisorbing to graphene respectively. The graphene physiometer allows micron spatial resolution and can differentiate immunoglobulin (IgG)-producing human embryonic kidney (HEK) cells from non-IgG-producing control cells. Population-based analyses allow mapping of phenotypic diversity, variances in metabolic activity, and cellular adhesion. Finally we show this platform can be extended to the detection of other analytes, e.g. dopamine. This work motivates the application of graphene as a unique biosensor for (sub)cellular interrogation.National Cancer Institute (U.S.) (Cancer Center Support (Core) Grant P30-CA14051)U.S. Army Research LaboratoryUnited States. Army Research Office. Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001)National Institute for Biomedical Imaging and Bioengineering (U.S.) (Grant P41EB015871-27)Skolkovo Institute of Science and Technolog
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