271 research outputs found

    SubcriticalWater – a Perspective ReactionMedia for Biomass Processing to Chemicals: Study on Cellulose Conversion as aModel for Biomass

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    Biomass and water are recognized as a key renewable feedstock in sustainable production of chemicals, fuels and energy. Subcritical water (SubCW), or commonly referred as hot compressed water (HCW), is the water above boiling and below critical point (CP; 374 °C, 22.1 MPa). It has gained great attention in the last few decades as a green, cheap, and nontoxic reagent for conversion of biomass into valuable chemicals. In this paper, hydrothermal reactions of cellulose, as the model biomass substance, with subcritical water at mild temperature and pressure regimes have been studied. The experiments were done in a batch reactor in the temperature range of 220 ° – 300 °C. The main products distributed in liquid, gaseous and solid phase were separated and quantified. The conversions to each group of products were found strongly dependent on the temperature and residence time

    Mobilization with cyclophosphamide reduces the number of lymphocyte subpopulations in the leukapheresis product and delays their reconstitution after autologous hematopoietic stem cell transplantation in patients with multiple myeloma

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    Abstract Background Autologous hematopoietic stem cell transplantation is considered the standard of care for younger patients with multiple myeloma. Several mobilization regimens are currently used, most commonly growth factors alone or in combination with chemotherapy. The aim of our study was to investigate the differences in lymphocyte subpopulation counts between three different mobilization regimens on collection day, in the leukapheresis product and on day 15 after autologous hematopoietic stem cell transplantation. Patients and methods In total 48 patients were prospectively enrolled in three different mobilization regimens; (i) filgrastim (20), (ii) pegfilgrastim (19) and (iii) cyclophosphamide + filgrastim (9). Lymphocytes, CD16+/56+ natural killer and CD4+/CD25high T regulatory cells were determined by flow cytometry. Results We found a statistically significant difference between the mobilization regimens. Cyclophosphamide reduced lymphocyte and natural killer (NK) cell counts on collection day (lymphocytes 1.08 × 109/L; NK cells 0.07 × 109/L) compared to filgrastim (lymphocytes 3.08 × 109/L; NK cells 0.52 × 109/L) and pegfilgrastim (lymphocytes 3 × 109/L; NK cells 0.42 × 109/L). As a consequence lymphocyte and NK cell counts were also lower in the leukapheresis products following cyclophosphamide mobilization regimen (lymphocytes 50.1 × 109/L; NK cells 4.18 × 109/L) compared to filgrastim (lymphocytes 112 × 109/L; NK cells 17.5 × 109/L) and pegfilgrastim (lymphocytes 112 × 109/L; NK cells 14.3 × 109/L). In all mobilization regimens T regulatory cells increased 2-fold on collection day, regarding the base line value before mobilization. There was no difference in T regulatory cell counts between the regimens. Conclusions Mobilization with cyclophophamide reduces the number of mobilized and collected lymphocytes and NK cells as compared to mobilization with growth factors only and results in their delayed reconstitution following autologous hematopoietic stem cell transplantation. We found no difference between filgrastim and pegfilgrastim mobilization. </jats:sec

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    Antioxidant, Radical Scavenging and Antimicrobial Activities of Red Onion (Allium cepa L) Skin and Edible Part Extracts

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    The antioxidant, radical scavenging and antimicrobial activities of extracts from skin and edible part of red onion have been investigated. Crude extracts of red onion were obtained separately with acetone, ethanol and mixtures of solvents with water. The amounts of isolated phenolic compounds and quercetin from onion skin were approximately 3 to 5 times higher as from the onion edible part. Antioxidant and radical scavenging activities of onion skin extracts were generally high, results were comparable to that of BHT. Extracts from onion edible part showed somewhat lower activity. Furthermore, high activity of skin extracts against bacteria Escherichia coli, Pseudomonas fluorescens and Bacillus cereus and fungi Aspergillus niger, Trichoderma viride and Penicillium cyclopium was observed. Antimicrobial activity of edible part extracts against tested microorganisms is generally lower, while for Escherichia coli no growth inhibition was observed

    Integrated Process to Obtain Anthocyanin Enriched Palm-Fat Particles from Elderberry Juice

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    Two novel technologies were applied in order to investigate concentration and formulation of anthocyanins for potential use in food industry. Integrated membrane process technology was applied for concentrating elderberry juice. In the first step, the juice was clarified by microfiltration, followed by a pre-concentration step with reverse osmosis. Finally, the juice was concentrated to the end concentration of 56 °Brix by osmotic distillation. The elderberry juice concentrate was formulated in a powderous form by a high-pressure process — Particles from Gas Saturated Solution (PGSS™) — using supercritical CO2. The applied carrier material was palm fat. The products with different anthocyanin-carrier ratios were measured for their colour properties (lightness, hue angle, and saturation). Colour stability was monitored for prolonged storage at different conditions (light/dark and ambient temperature/ refrigerator). The obtained powderous anthocyanin-palm fat products showed good colour stability, which gives good bases for potential applications in the future

    Hydrothermal Degradation of Fats, Carbohydrates and Proteins in Sunflower Seeds after Treatment with Subcritical Water

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    In this study, the hydrothermal degradation of fats, carbohydrates and proteins in sunflower seeds after treatment with subcritical water was observed. Sunflower seeds were subjected to subcritical water in a wide temperature range (130–240 °C) for periods from 5 to 120 minutes. The oil- and water-soluble phases were analysed for products of hydrothermal degradation. Oil stability was investigated by analysing the content of free fatty acids using gas chromatography. The water-soluble phase was analysed for the presence of any formed amino acids, and the amount of carbohydrates remaining after treatment was determined. Total amino acids and carbohydrates were determined using the ninhydrin and phenol/sulphuric acid spectrophotometric methods, respectively. The results show that oils are the most stable macronutrient present in sunflower seeds. Only small amounts of free fatty acids had formed during processing but the amount drastically started to increase at 240 °C. Proteins seem to be less stable than oils, whereas carbohydrates have proven to be very susceptible to hydrothermal degradation

    Double-diffusive natural convection within a 3D porous enclosure, using the boundary element method

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    Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.A three-dimensional numerical study based on the boundary element method (BEM) was performed in order to study the problem of double-diffusive natural convection within a cubic enclosure filled with a fluid-saturated porous media, and subjected to horizontal temperature and concentration gradients. The fluid-flow within the porous media was modeled using space-averaged Navier-Stokes equations, coupled with energy and species equations. The used numerical algorithm is based on a combination of single domain and sub-domain BEM, and solves the velocity-vorticity formulation of the governing equations. The influences of the main controlling parameters, such as the porous Rayleigh number, Darcy number, Lewis number, and the buoyancy coefficient were investigated, by focusing on those situations, where the flowfield becomes 3D. The results for overall heat and solutetransfer through the porous enclosure are presented in terms of Nusselt and Sherwood numbers as functions of the governing parameters, and then compared to the numerical benchmarks published in literature.mp201

    Protection of deoxyribose and DNA from degradation by using aqueous extracts of several wild plants

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    BACKGROUND: Aqueous extracts of 48 herbal plants were obtained via alternative extraction protocols, and were assayed for their capacity to protect deoxyribose and DNA itself from degradation (or, conversely, for their capacity to promote DNA degradation), using electrophoresis as analytical tool. RESULTS: For a given (constant) volume of extract, deoxyribose protection ranged from 14.13 ± 1.35% (mean ± SD) inhibition by dwarf mallow powder infusion, up to 106.51 ± 15.93% inhibition by avocado powder infusion. DNA protection was tested at two extract concentrations, and was slightly greater at the higher concentration. Pro-oxidant effects were essentially absent. CONCLUSION: The anti-oxidative roles of plants upon deoxyribose and DNA displayed by our experimental results were rather promising with regards to practical applications of those plants, viz. as ingredients in the formulation of nutraceutical beverages and/or foods

    Boundary element formulations for the numerical solution of two-dimensional diffusion problems with variable coefficients

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    This is the post-print version of the final paper published in Computers & Mathematics with Applications. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2012 Elsevier B.V.This paper presents new formulations of the radial integration boundary integral equation (RIBIE) and the radial integration boundary integro-differential equation (RIBIDE) methods for the numerical solution of two-dimensional diffusion problems with variable coefficients. The methods use either a specially constructed parametrix (Levi function) or the standard fundamental solution for the Laplace equation to reduce the boundary-value problem (BVP) to a boundary–domain integral equation (BDIE) or boundary–domain integro-differential equation (BDIDE). The radial integration method (RIM) is then employed to convert the domain integrals arising in both BDIE and BDIDE methods into equivalent boundary integrals. The resulting formulations lead to pure boundary integral and integro-differential equations with no domain integrals. Furthermore, a subdomain decomposition technique (SDBDIE) is proposed, which leads to a sparse system of linear equations, thus avoiding the need to calculate a large number of domain integrals. Numerical examples are presented for several simple problems, for which exact solutions are available, to demonstrate the efficiency of the proposed approaches
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