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Different Fractions (different + fraction)
Selected AbstractsAnti-inflammatory and analgesic activities of the ethanolic extracts from Zanthoxylum riedelianum (Rutaceae) leaves and stem barkJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2007Leonardo Mandalho Lima We have evaluated the anti-inflammatory and analgesic properties of the leaves (LCE) and stem bark (BCE) crude extracts of Zanthoxylum riedelianum (Rutaceae). Different fractions of the stem bark extract (hexane, BCEH; dichloromethane, BCED; ethyl acetate, BCEE; and lyophilized aqueous residual, BCEW) were also investigated. We studied the effects of the extracts and fractions using the rat paw oedema test induced by carrageenan, dextran, histamine or nystatin; the mouse abdominal constriction test; the mouse hot-plate test (only for LCE and BCE); and the mouse formalin test. Both extracts and all BCE fractions displayed anti-inflammatory activity in the carrageenan-induced oedema model, but not for dextran, histamine or nystatin. Considering the analgesic models, both extracts showed antinociceptive activity, but BCE was more active than LCE in models of central pain. All BCE fractions showed significant inhibition in the abdominal constriction test and in both phases of the formalin test. When BCED was submitted to phytochemical procedures it led to the isolation of six lignans (sesamin, methylpluviatolide, dimethylmatairesinol, piperitol-4,-O-,,,-dimethylallyl ether, kaerophyllin and hinokinin), and a triterpene (lupeol). Inhibition of cyclooxygenase and its metabolites may have been involved in the mechanism of action of this plant, considering previous studies reporting the anti-inflammatory and analgesic activity for the identified lignans, as well as anti-inflammatory activity for lupeol. [source] A unified mechanism for protein folding: Predetermined pathways with optional errorsPROTEIN SCIENCE, Issue 3 2007Mallela M.G. Krishna Abstract There is a fundamental conflict between two different views of how proteins fold. Kinetic experiments and theoretical calculations are often interpreted in terms of different population fractions folding through different intermediates in independent unrelated pathways (IUP model). However, detailed structural information indicates that all of the protein population folds through a sequence of intermediates predetermined by the foldon substructure of the target protein and a sequential stabilization principle. These contrary views can be resolved by a predetermined pathway,optional error (PPOE) hypothesis. The hypothesis is that any pathway intermediate can incorporate a chance misfolding error that blocks folding and must be reversed for productive folding to continue. Different fractions of the protein population will then block at different steps, populate different intermediates, and fold at different rates, giving the appearance of multiple unrelated pathways. A test of the hypothesis matches the two models against extensive kinetic folding results for hen lysozyme which have been widely cited in support of independent parallel pathways. The PPOE model succeeds with fewer fitting constants. The fitted PPOE reaction scheme leads to known folding behavior, whereas the IUP properties are contradicted by experiment. The appearance of a conflict with multipath theoretical models seems to be due to their different focus, namely on multitrack microscopic behavior versus cooperative macroscopic behavior. The integration of three well-documented principles in the PPOE model (cooperative foldons, sequential stabilization, optional errors) provides a unifying explanation for how proteins fold and why they fold in that way. [source] Oxidative mutagenicity of polar fractions from polycyclic aromatic hydrocarbon,contaminated soilsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2008Joanna Park Abstract Soils at hazardous waste sites contain complex mixtures of chemicals and often are difficult to characterize in terms of risk to human and ecological health. Over time, biogeochemical processes can decrease the apparent concentrations of pollutants but also can lead to accumulation of new products for which toxicity and behavior in the environment are largely unknown. A bioassay-directed fractionation technique was used to assess the contribution of redox-active bacterial metabolites to the toxicity of soil contaminated with polycyclic aromatic hydrocarbons (PAHs). A reverse mutation assay with Escherichia coli WP2 uvrA/pKM101 (IC188) and E. coli WP2 uvrA oxyR/pKM101 (IC203) was used to screen fractions for genotoxicity. Strain IC203 carries the ,oxyR30 mutation, which prevents the expression of antioxidant proteins in response to oxidative stress and increases its reversion by compounds that generate reactive oxygen species (ROS). Polar fractions of PAH-contaminated soil extracts were mutagenic to strain IC203 but not to strain IC188, suggesting the involvement of ROS in genotoxicity. Genotoxic potencies ranged from 300 to 1,700 revertants per milligram of fraction. Catalase was able to decrease IC203 reversion, implicating the involvement of hydrogen peroxide as a key ROS. Oxidized PAH compounds, including quinones, were identified in the mutagenic fractions but were not by themselves mutagenic. Deasphalted whole extracts and recombined fractions were not mutagenic, indicating that interactions between compounds in different fractions can mitigate genotoxicity. [source] Biological significance of metals partitioned to subcellular fractions within earthworms (Aporrectodea caliginosa),ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2006Martina G. Vijver Abstract Metal ions in excess of metabolic requirements are potentially toxic and must be removed from the vicinity of important biological molecules to protect organisms from adverse effects. Correspondingly, metals are sequestrated in various forms, defining the accumulation pattern and the magnitude of steady-state levels reached. To investigate the subcellular fractions over which Ca, Mg, Fe, Cu, Zn, Cd, Pb, Ni, and As are distributed, earthworms (Aporrectodea caliginosa) collected from the field were analyzed by isolating metal-rich granules and tissue fragments from intracellular microsomal and cytosolic fractions (i.e., heat-stable proteins and heat-denatured proteins). The fractions showed metal-specific binding capacity. Cadmium was mainly retrieved from the protein fractions. Copper was equally distributed over the protein fraction and the fraction comprising tissue fragments, cell membranes, and intact cells. Zinc, Ca, Mg, and As were mainly found in this fraction as well. Lead, Fe, and Ni were mainly isolated from the granular fraction. To study accumulation kinetics in the different fractions, three experiments were conducted in which earthworms were exposed to metal-spiked soil and a soil contaminated by anthropogenic inputs and, indigenous earthworms were exposed to field soils. Although kinetics showed variation, linear uptake and steady-state types of accumulation patterns could be understood according to subcellular compartmentalization. For risk assessment purposes, subcellular distribution of metals might allow for a more precise estimate of effects than total body burden. Identification of subcellular partitioning appears useful in determining the biological significance of steady-state levels reached in animals. [source] Theoretical framework for the distribution of trace metals among the operationally defined speciation phases of a sedimentENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2001René A. Nome Abstract The use of a model based on Langmuir's isotherm to evaluate the metal associated with separate geochemical phases of a sediment is proposed and its validity tested with sediments of certified composition. The model takes into account a standard procedure for a certified reference material (CRM601), which defines, experimentally, a set of sequential extractions that divide the sediment into four operational fractions. The derived equations allow the treatment of data from sediment of Flumendosa Lake, Italy, and certified material CRM601 and also allow the computation of corrected concentrations, i.e., the metal affinities for each fraction. Experimental values for Ni show its low sensitivity and an equal distribution among different phases, which suggests a similar adsorption mechanism in all cases. In the case of Cd, the corrected concentration in the Fe/Mn oxide phase is nine times higher than for the residual fraction. For sediment of the Bèsos River, Spain, results show the percentage distribution of Ni over different fractions. Affinity values for Ni on a Flumendosa Lake sediment have also been calculated. The present model is simple to apply and shows satisfactory agreement with experimental data. [source] Potential Bioelectroactive Bone Regeneration Polymer Nanocomposites with High Dielectric Permittivity,ADVANCED ENGINEERING MATERIALS, Issue 10 2009Zhi-Min Dang The frequency dependence of the dielectric permittivity of (barium titanate,hydroxyapatite)/poly(vinylidene fluoride) three-phase nanocomposites is investigated at room temperature and different fractions of barium titanate. The permittivity increases with increasing concentration of barium titanate. A weak decrease in permittivity is also observed for frequencies below 106 Hz. The SEM image inset in a dielectric permittivity vs. frequency curve shows that rod-like hydroxyapatite and sphere-like barium titanate nanoparticles exist in the three-phase nanocomposites. [source] Exciton,Exciton Annihilation in Mixed-Phase Polyfluorene FilmsADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Paul E. Shaw Abstract Singlet,singlet annihilation is studied in polyfluorene (PFO) films containing different fractions of , -phase chains using time-resolved fluorescence. On a timescale of >15,ps after excitation, the results are fitted well by a time-independent annihilation rate, which indicates that annihilation is controlled by 3D exciton diffusion. A time-dependent annihilation rate is observed during the first 15,ps in the glassy phase and in the , -phase rich films, which can be explained by the slowdown of exciton diffusion after excitons reach low-energy sites. The annihilation rate in the mixed-phase films increases with increasing fraction of , -phase present, indicating enhanced exciton diffusion. The observed trend agrees well with a model of fully dispersed, -phase chromophores in the surrounding glassy phase with the exciton diffusion described using the line-dipole approximation for an exciton wavefunction extending over 2.5,nm. The results indicate that glassy and, -phase chromophores are intimately mixed rather than clustered or phase-separated. [source] Feeding value of enset (Ensete ventricosum), Desmodium intortum hay and untreated or urea and calcium oxide treated wheat straw for sheepJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2009A. Nurfeta Summary Feed intake, in vivo nutrient digestibility and nitrogen utilization were evaluated in male sheep fed different fractions (leaf, pseudostem, corm, whole plant) of enset, untreated or 2% urea- and 3% calcium oxide- (CaO or lime) treated wheat straw and Desmodium intortum hay as sole diets. All feeds, except D. intortum hay and enset leaf had low crude protein (CP) content. Non-fiber carbohydrate contents were higher in enset fractions, especially in pseudostem and corm relative to other feeds. Enset leaf and pseudostem had high calcium, phosphorus and manganese contents. Corm, whole enset and D. intortum hay were rich sources of zinc. Daily dry matter and CP intakes were higher (p < 0.05) in sheep fed D. intortum hay (830 and 133 g, respectively) than those fed pseudostem (92 and 7.8 g, respectively). Organic matter digestibilities were highest for corm (0.780) and whole enset (0.776) and lowest for D. intortum hay (0.534) and untreated wheat straw (0.522). The CP digestibility ranged from 0.636 in D. intortum hay to 0.408 in corm. Nitrogen (N) balance was highest (p < 0.05) in D. intortum hay (10.4 g/day) and lowest in corm (,1.3 g/day). Enset leaf could be a useful protein supplement whereas the pseudostem and corm could be good sources of energy. [source] Affinity and catalytic heterogeneity of polyclonal myelin basic protein-hydrolyzing IgGs from sera of patients with multiple sclerosisJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2010Galina A. Legostaeva Abstract Human myelin basic protein (hMBP)-hydrolyzing activity was recently shown to be an intrinsic property of antibodies (Abs) from multiple sclerosis (MS) patients. Here, we present the first evidence demonstrating a significant diversity of different fractions of polyclonal IgGs (pIgGs) from MS patients in their affinity for hMBP and in the ability of pIgGs to hydrolyze hBMP at different optimal pHs (3,10.5). IgGs containing ,- and ,-types of light chains demonstrated comparable relative activities in the hydrolysis of hMBP. IgGs of IgG1,IgG4 sub-classes were analyzed for catalytic activity. IgGs of all four sub-classes were catalytically active, with their contribution to the total activity of Abzs in the hydrolysis of hMBP and its 19-mer oligopeptide increasing in the order: IgG1 (1.5,2.1%) < IgG2 (4.9,12.8%) < IgG3 (14.7,25.0%) < IgG4 (71,78%). Our findings suggest that the immune systems of individual MS patients generate a variety of anti-hMBP abzymes with different catalytic properties, which can attack hMBP of myelin-proteolipid shell of axons, playing an important role in MS pathogenesis. [source] Syzygium cumini leaf and seed extract mediated biosynthesis of silver nanoparticles and their characterizationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2010Vineet Kumar Abstract BACKGROUND: Plant mediated synthesis of metallic nanoparticles has been studied and reported, however, to date, the biomolecules involved in the synthesis of metallic nanoparticles have not been characterized. This study was therefore undertaken to characterize the biomolecules of Syzygium cumini involved in the synthesis of silver nanoparticles. RESULTS: Synthesis kinetics and morphological characterization of silver nanoparticles (SNP) synthesized using leaf extract (LE) and seed extract (SE) as well as their polar (water) fractions from Syzygium cumini were compared. The polyphenols content and high performance liquid chromatography (HPLC) profile of different fractions revealed good correlation between size and synthesis rate of SNP. SE contains more polyphenols and biochemical constituents than LE and therefore, showed higher synthesis rate and bigger sized SNP. To analyse the nature of biomolecules involved in the synthesis of SNP, LE and SE were fractionated on a polarity basis by solvent,solvent partitioning. Only the water fractions of LE and SE showed potential for SNP synthesis. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis of SNP indicated that all fractions catalyze the synthesis of spherical nanoparticles. The average size of SNP synthesized by LE, leaf water fraction, SE and seed water fraction were 30, 29, 92, and 73 nm respectively. CONCLUSION: Results suggest that only highly polar soluble constituents are responsible for SNP synthesis. The size of SNP was found to be directly correlated with the amount of polyphenols as well as surfactants present in the reaction solution. Thus, the amount of polyphenols could be one of the crucial parameters determining the size and distribution of SNP. Copyright © 2010 Society of Chemical Industry [source] EFFECT OF COMPOSITION OF GLUTHNIN SUBFRACTIONS ON RHEOLOGICAL PROPERTIES OF WHEATJOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2000S. JOOD ABSTRACT Gluten extracted from defatted flours of cv. Aubaine (extra-strong), Hereward (strong) and Riband (weak) was separated into five different fractions (R2 to R6) by sequential centrifugation and addition of sodium chloride. A seven-minute mixing time was used to carry out fractionation on the basis of depolymerization of glutenin macropolymers (GMP). Depolymerization of GMP occurred at much higher rates in dough of the weak cultivar compared to the strong and extra-strong cultivars. Polypeptide compositions of different ghttenin fractions were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis under reduced and non-reduced conditions, followed by densitometric scanning of stained patterns. The amount of HMW-glutenin subunits decreased and LMW-glutenin subunits increased correspondingly in each cultivar with the fractionation from R2 to R6. The rheological behavior of the fractions was analyzed by small deformation rheological tests (strain sweep and frequency tests). The high molecular weight fraction (R2) from extra-strong wheat had a higher vahte of G' and a lower tan , value as compared to strong and weak bread-making wheats. The moduli of HMW glutenin fractions (R2 and R3) were frequency independent and promoted the network properties, whereas moduli of LMW glutenin fractions were frequency dependent and gave rise to a plasticizing effect. Therefore, it was concluded from the present studies that HMW-glutenin subunits are not the only factors governing good bread-making quality but their proportions in relation to low molecular weight glutenin subunits is equally important in sinking a balance between viscous and elastic properties essential for bread making performance. [source] Echo combination to reduce proton resonance frequency (PRF) thermometry errors from fatJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2008Viola Rieke PhD Abstract Purpose To validate echo combination as a means to reduce errors caused by fat in temperature measurements with the proton resonance frequency (PRF) shift method. Materials and Methods Computer simulations were performed to study the behavior of temperature measurement errors introduced by fat as a function of echo time. Error reduction by combining temperature images acquired at different echo times was investigated. For experimental verification, three echoes were acquired in a refocused gradient echo acquisition. Temperature images were reconstructed with the PRF shift method for the three echoes and then combined in a weighted average. Temperature measurement errors in the combined image and the individual echoes were compared for pure water and different fractions of fat in a computer simulation and for a phantom containing a homogenous mixture with 20% fat in an MR experiment. Results In both simulation and MR measurement, the presence of fat caused severe temperature underestimation or overestimation in the individual echoes. The errors were substantially reduced after echo combination. Residual errors were about 0.3°C for 10% fat and 1°C for 20% fat. Conclusion Echo combination substantially reduces temperature measurement errors caused by small fractions of fat. This technique then eliminates the need for fat suppression in tissues such as the liver. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc. [source] Laser desorption/ionization techniques in the characterization of high-molecular-weight oil fractions,Part 2: de-asphalted oilsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2007Andrea Rizzi Abstract The composition of the de-asphalted oil fraction obtained from two different Italian fields was studied by laser desorption/ionization mass spectrometry. These fractions were treated with different solvent mixtures, and subfractions containing saturates, aromatic and polar compounds were obtained and analyzed by the same instrumental approach. The investigation showed clear differences between the samples coming from the two oils. The instrumental approach did not lead to an accurate description of the different components in terms of elemental composition and structures; however, valid information could be obtained on the molecular weight distribution of the components of the different fractions. Copyright © 2007 John Wiley & Sons, Ltd. [source] Antioxidant activity of Potentilla fruticosaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2004Giedrius Miliauskas Abstract The molecular structures of the radical scavenging compounds present in extracts of Potentilla fruticosa blossoms were elucidated and the antioxidant activities of various extracts were determined. The activities of the different fractions were monitored by off-line and on-line RP-HPLC DPPH, and ABTS,+ scavenging methods. Twelve compounds were isolated and identified, namely ellagic acid, catechin, quercetin-3-,-glucopyranoside, quercetin-3-,-galactopyranoside, quercetin-3-,-rutinoside, quercetin-3-,-glucuronopyranoside, quercetin-3-,-arabinofuranoside, kaempferol-3-,-rutinoside, kaempferol-3- O -,-(6,- O -(E)- p -coumaroyl)glucopyranoside, rhamnetin-3-,-glucopyranoside and rhamnetin-3-,-galactopyranoside. The radical scavenging activity of each isolated compound was measured using DPPH, and ABTS,+ assays and compared with the activity of rosmarinic acid. Catechin and ellagic acid were found to be the most active radical scavengers. The antioxidant properties of plant fractions were assessed in model systems by measuring superoxide anion and hydrogen peroxide scavenging, ,-carotene bleaching, hexanal production in edible oil, peroxide formation, and the increase in UV absorbance in the course of oxidation. Copyright © 2004 Society of Chemical Industry [source] Identification of taxanes in extracts from leaves of Taxus baccata L. using 13C-NMR spectroscopyPHYTOCHEMICAL ANALYSIS, Issue 3 2009Emilie Duquesnoy Abstract Introduction The study of taxanes is a hot topic worldwide because of their potential activity against cancer. Analysis of taxanes in extracts of various Taxus species is generally achieved using HPLC. Objective The aim of the current work was to identify taxanes in different fractions of extracts from Taxus baccata L. using the computer-aided analysis of their 13C-NMR spectra. Methodology A computerised procedure, based on 13C-NMR spectroscopy using literature data, has been developed in order to identify taxoids in natural mixtures. Leaves and twigs of T. baccata were extracted with various solvents and the extracts were fractionated according to rapid fractionation schemes described in the literature. Results The computer-assisted analysis of the 13C-NMR spectra of the fractions of chromatography led to the identification of 16 taxanes belonging to the taxine, taxicine, taxinine and taxuspine families. Conclusion It has been shown that 13C-NMR is a powerful alternative tool for the identification of taxanes in extracts of leaves and twigs of various Taxus species after a rapid fractionation step. Copyright © 2009 John Wiley & Sons, Ltd. [source] Molecular mass ranges of coal tar pitch fractions by mass spectrometry and size-exclusion chromatographyRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2009F. Karaca A coal tar pitch was fractionated by solvent solubility into heptane-solubles, heptane-insoluble/toluene-solubles (asphaltenes), and toluene-insolubles (preasphaltenes). The aim of the work was to compare the mass ranges of the different fractions by several different techniques. Thermogravimetric analysis, size-exclusion chromatography (SEC) and UV-fluorescence spectroscopy showed distinct differences between the three fractions in terms of volatility, molecular size ranges and the aromatic chromophore sizes present. The mass spectrometric methods used were gas chromatography/mass spectrometry (GC/MS), pyrolysis/GC/MS, electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) and laser desorption time-of-flight mass spectrometry (LD-TOFMS). The first three techniques gave good mass spectra only for the heptane-soluble fraction. Only LDMS gave signals from the toluene-insolubles, indicating that the molecules were too involatile for GC and too complex to pyrolyze into small molecules during pyrolysis/GC/MS. ESI-FTICRMS gave no signal for toluene-insolubles probably because the fraction was insoluble in the methanol or acetonitrile, water and formic acid mixture used as solvent to the ESI source. LDMS was able to generate ions from each of the fractions. Fractionation of complex samples is necessary to separate smaller molecules to allow the use of higher laser fluences for the larger molecules and suppress the formation of ionized molecular clusters. The upper mass limit of the pitch was determined as between 5000 and 10,000,u. The pitch asphaltenes showed a peak of maximum intensity in the LDMS spectra at around m/z 400, in broad agreement with the estimate from SEC. The mass ranges of the toluene-insoluble fraction found by LDMS and SEC (400,10,000,u with maximum intensity around 2000,u by LDMS and 100,9320,u with maximum intensity around 740,u by SEC) are higher than those for the asphaltene fraction (200,4000,u with maximum intensity around 400,u by LDMS and 100,2680,u with maximum intensity around 286,u by SEC) and greater than values considered appropriate for petroleum asphaltenes (300,1200,u with maximum intensity near 700,u). Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of stable carbon isotopes of organic acids and carbonaceous aerosols in the atmosphereRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2006R. Fisseha A wet oxidation method for the compound-specific determination of stable carbon isotopes (,13C) of organic acids in the gas and aerosol phase, as well as of water-soluble organic carbon (WSOC), is presented. Sampling of the organic acids was done using a wet effluent diffusion denuder/aerosol collector (WEDD/AC) coupled to an ion chromatography (IC) system. The method allows for compound-specific stable carbon isotope analysis by collecting different fractions of organic acids at the end of the IC system using a fraction collector. ,13C analyses of organic acids were conducted by oxidizing the organic acids with sodium persulfate at a temperature of 100°C and determining the ,13C value of the resulting carbon dioxide (CO2) with an isotope ratio mass spectrometer. In addition, analysis of ,13C of the WSOC was performed for particulate carbon collected on aerosol filters. The WSOC was extracted from the filters using ultrapure water (MQ water), and the dissolved organic carbon was oxidized to CO2 using the oxidation method. The wet oxidation method has an accuracy of 0.5, with a precision of ±0.4, and provides a quantitative result for organic carbon with a detection limit of 150,ng of carbon. Copyright © 2006 John Wiley & Sons, Ltd. [source] Speciation of essential and toxic elements in edible mushrooms: size-exclusion chromatography separation with on-line UV,inductively coupled plasma mass spectrometry detectionAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2004Rodolfo G. Wuilloud Abstract Size-exclusion liquid chromatography was coupled to UV and inductively coupled plasma mass spectrometry (ICP-MS) for detection to perform elemental speciation studies on different edible mushrooms. Molecular weight (MW) distribution patterns of several elements among different fractions present in various edible mushrooms are presented. The association of the elements with the high and low MW fractions was observed using sequential detection by UV and ICP-MS. Separation was performed using a Superdex 75 column. Variability of the fractionation patterns with three different extraction media (0.05 mol l,1 NaOH; 0.05 mol l,1 HCl; hot water at 60°C) was evaluated for mushroom species. A comparative elemental speciation study was performed in order to determine the differences in the fractionation patterns of silver, arsenic, cadmium, mercury, lead, and tin in Boletus edulis, Agaricus bisporus, and Lentinus edodes. Differences in the fractionation patterns of the elements were found to depend on the mushroom species and the extraction medium. Most of the elements were associated with high mw fractions. It was not possible to assess the trace metal contributions from the mushroom growth media. Copyright © 2004 John Wiley & Sons, Ltd. [source] Comparing different fractions of a factorial design: a metal cutting case studyAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 2 2007E. Mønness Abstract Full factorial designs of a significant size are very rarely performed in industry due to the number of trials involved and unavailable time and resources. The data in this paper were obtained from a six-factor full factorial (26) designed experiment that was conducted to determine the optimum operating conditions for a steel milling operation. Fractional-factorial designs 2 (one-eighth) and 2 (one-fourth, using a fold-over from the one-eighth) are compared with the full 26 design. Four of the 2 are de-aliased by adding four more runs. In addition, two 12-run Plackett,Burman experiments and their combination into a fold-over 24-run experiment are considered. Many of the one-eighth fractional-factorial designs reveal some significant effects, but the size of the estimates varies much due to aliasing. Adding four more runs improves the estimation considerably. The one-quarter fraction designs yield satisfactory results, compared to the full factorial, if the ,correct' parameterization is assumed. The Plackett,Burman experiments, estimating all main effects, always perform worse than the equivalent regular designs (which have fewer runs). When considering a reduced model many of the different designs are more or less identical. The paper provides empirical evidence for managers and engineers that the choice of an experimental design is very important and highlights how designs of a minimal size may not always result in productive findings. Copyright © 2006 John Wiley & Sons, Ltd. [source] Development of a method to assess binding of astaxanthin to Atlantic salmon Salmo salar L. muscle proteinsAQUACULTURE RESEARCH, Issue 4 2005Madhury R Saha Abstract Several methods were examined to characterize the binding between astaxanthin and salmon muscle protein(s) in order to provide tools for evaluation of the role of muscle proteins on astaxanthin retention in Atlantic salmon Salmo salar L. flesh. The methods included gel filtration chromatography, displacement of a hydrophobic probe and ultrafiltration. With gel filtration chromatography, aggregation of astaxanthin under the experimental conditions was a major problem for the separation of bound astaxanthin from free astaxanthin because the apparent molecular weight of aggregated astaxanthin or astaxanthin micelles was in the range of protein,astaxanthin complexes. Displacement of the fluorescent probe 8-anilino-1-naphthalenesulphonate (ANS) was not effective as astaxanthin quenched the fluorophore so that displacement could not be observed. An ultrafiltration method was developed using 200-mM sodium cholate for dispersion of astaxanthin aggregates. This allowed unbound astaxanthin to be separated from bound astaxanthin using a 30-kDa filter. After salmon muscle proteins were solubilized in different fractions by sequential extraction using low ionic strength solutions, the astaxanthin binding of different fractions was assessed using the ultrafiltration method. The significant difference (P<0.05) observed in the astaxanthin binding of the various fractions suggests an application of this assay to detect differences in affinity of proteins for astaxanthin. The results also suggest that proteins other than actomyosin or actin can bind astaxanthin in Atlantic salmon flesh. This method can be used for the identification of astaxanthin-binding proteins in salmon flesh and other tissues. [source] Operation of a municipal solid waste co-combustion pilot plantASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2007V. K. C. Lee Abstract The co-combustion of municipal solid waste (MSW) is a novel and highly integrated design combining cement manufacturing, thermal processing of MSW and energy/electricity production (termed the Co-Co process). This novel design of the Co-Co process was developed in 2003,2004 and a pilot plant with a capacity of 40 tonnes per day was constructed and commissioned in 2005. The pilot plant was operated for a period of 10 weeks during 2005. Various feed protocols, namely, MSW as received and after removal of recyclables, were tested. Stack emissions were monitored either continuously (gas emission) or periodically (dioxins and heavy metal emissions). Solid residues including bottom ash and fly ash were also sampled and analysed for heavy metals and dioxins periodically. It was found that the levels of dioxins in the stack emissions and fly ash were below normal MSW thermal treatment processes, and government environmental and international limits (more than 1000 times less). Other gases, such CO, NOx, SOx and HCl, were also well below government environmental licence limits as defined by a best practical means (BPM). In addition, the materials recovery and recycling facility (MRRF) was tested. It demonstrated that different fractions, including metals, plastics and glass, of the MSW could be separated and recovered. The Co-Co process was successfully demonstrated and its emission levels were well below normal MSW thermal treatment processes. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||||||||