Home About us Contact
|
Home About us Contact | ||
|
|
||
Compositional
Terms modified by Compositional Selected AbstractsAn electron microprobe study of P645/T390: Evidence for an Early Helladic III Lerna,Aegina connectionGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2002Michael J. Dorais Middle Helladic Aeginetan Ware is widely distributed throughout the Aegean. It is characterized by a "gold mica or volcanic ash" fabric and is abundant at Lerna on the Argive plain, Greece, in the Middle Helladic and Late Helladic I periods. A group of Early Helladic III ceramics at Lerna includes P645/T390, which also has a volcanic fabric. We have sampled all the major rock types of the separate volcanic episodes on Aegina, Methana, and Poros and analyzed the constituent minerals with the electron microprobe. These analyses provide a reference standard against which the mineralogy of P645/T390 and other potential Aeginetan wares can be compared. The compositions of amphibole, clinopyroxene, plagioclase, and biotite in P645/T390 are identical to the same minerals in dacites on Aegina, suggesting an origin on that island. Compositional mismatches with the minerals of Methana and Poros indicated the ceramic was not manufactured at these locations. This narrow-necked jar represents the earliest occurrence of Aeginetan Ware on mainland Greece that has been confirmed by a quantitative method. © 2002 Wiley Periodicals, Inc. [source] Characterisation of soybean glycinin and ,-conglycinin fractionated by using MgCl2 instead of CaCl2INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2010Chong Liu Summary A simple two step precipitation method was used to investigate the effect of MgCl2 instead of CaCl2 on fractionation of soybean glycinin and ,-conglycinin. Compositional and physicochemical properties of the resulting protein fractions were characterised. The optimised procedure, in terms of protein yield, purity, phytate content and physicochemical properties, was obtained when the addition of 5 mm MgCl2 was used. After application of 5 mm MgCl2, the phytate content of the glycinin-rich and ,-conglycinin-rich fractions was about 0.4% and 1.3%, respectively, but the addition of 5 mm CaCl2 increased the phytate content of the glycinin-rich fraction to 1.25% and decreased that of ,-conglycinin-rich fraction to 0.67%. Low phytate protein product was suitable for use in infant formula and acidic food. The solubility of the glycinin-rich fractions with MgCl2 was significantly higher than that with CaCl2 at pH < 4.5. Application of MgCl2 improved thermal stability of the ,-conglycinin-rich fraction. [source] Compositional and configurational sequence determination of methyl methacrylate/ethyl acrylate copolymers by one- and two-dimensional nuclear magnetic resonance spectroscopyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2003A. S. Brar Abstract Ethyl acrylate (E)/methyl methacrylate (M) copolymers of different compositions were prepared, and their compositions were determined with 1H NMR spectra. The complete spectral assignments, in terms of the compositional and configurational sequences of these copolymers, were made with the help of distortionless enhancement by polarization transfer and two-dimensional heteronuclear single quantum coherence spectroscopy. The ,-(CH3)M, CH (E), CH2, and ,CO carbons of both M and E units were found to be sensitive to various compositional and configurational sequences. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 313,326, 2003 [source] Compositional and degradative changes during the manufacture of dry-cured ,lacón'JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2003José M Lorenzo Abstract The gross and mineral composition, the main physicochemical parameters, the protein extractability and the proteolytic (nitrogen fractions and free amino acids) and lipolytic (acidity index and free fatty acids) changes were studied throughout the manufacturing process of five batches of dry-cured ,lacón', a traditional Spanish meat product made from the fore-ham of the pig following a similar technological process to that of dry-cured ham. The main compositional characteristics of this product are the high NaCl content and the low moisture content at the end of the curing process. The pH remained fairly stable (around 6) throughout the whole process and a fall in aw was observed, reaching very low (0.767 ± 0.052) final average values. It was noted that 76% of the sarcoplasmic and 83% of the myofibrillar proteins became insoluble during the manufacturing process. The values of the different nitrogen fractions increased in a significant manner during manufacture, reaching low final values that indicate that ,lacón' undergoes a low level of proteolysis in comparison with other products manufactured by similar technologies. The high NaCl content and the intense dehydration suffered during the manufacturing process appear to be the principal causes of this reduced protein degradation. In accordance with the limited increase in the ,-amino acidic nitrogen during ripening, the total free amino acid content increased slightly but significantly from average values of 4371 mg kg,1 dry matter in fresh pieces to average values of 13 020 mg kg,1 dry matter in pieces at the end of the ripening process. The profile of free amino acids in the final product was similar to that observed by other authors in dry-cured ham. The acidity of the fat increased by a factor of five. The final average values (49.9 g oleic acid kg,1) were lower than those determined in dry-cured ham, which indicates that ,lacón' undergoes less lipolysis during the ripening process than dry-cured ham. C18 : 1, C18 : 2 and C16 were the most intensively released fatty acids during curing. The profile of free fatty acids in the end product was in agreement with that observed by other authors in dry-cured ham. Copyright © 2003 Society of Chemical Industry [source] Influence of composition and structure of oil-in-water emulsions on retention of aroma compoundsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2002Dr Saskia M van Ruth Abstract The influence of the composition and structure of oil-in-water emulsions on aroma retention was examined for 20 volatile compounds. Compositional and structural parameters included the fraction of emulsifier phase, the fraction of lipid phase and the particle size distribution of the dispersed lipid phase in the emulsion. Air/liquid partition coefficients of dimethyl sulphide, 1-propanol, diacetyl, 2-butanone, ethyl acetate, 1-butanol, 2-pentanol, propyl acetate, 3-methyl-1-butanol, ethyl butyrate, hexanal, butyl acetate, 1-hexanol, 2-heptanone, heptanal, ,-pinene, 2-octanone, octanal, 2-nonanol and 2-decanone were determined by static headspace gas chromatography. The hydrophobicity of the compounds determined the influence of the compositional and structural parameters of the emulsions on air/liquid partitioning. Increase of the emulsifier fraction increased the retention of mainly hydrophilic aroma compounds and decreased the retention of hydrophobic compounds. Higher lipid levels led to increased retention of hydrophobic compounds and release of hydrophilic compounds. Emulsions with larger particles showed increased aroma retention, which was independent of the lipid fraction and the polarity of the aroma compounds. The data demonstrated a profound effect of both composition and structure of oil-in-water emulsions on the air/liquid partitioning of the 20 aroma compounds under equilibrium conditions. © 2002 Society of Chemical Industry [source] Compositional and lithological diversity among brecciated lunar meteorites of intermediate iron concentrationMETEORITICS & PLANETARY SCIENCE, Issue 9 2009Randy L. Korotev Most have iron concentrations intermediate to those of the numerous feldspathic lunar meteorites (3,7% FeO) and the basaltic lunar meteorites (17,23% FeO). All but one are polymict breccias. Some, as implied by their intermediate composition, are mainly mixtures of brecciated anorthosite and mare basalt, with low concentrations of incompatible elements such as Sm (1,3 ,g/g). These breccias likely originate from points on the Moon where mare basalt has mixed with material of the FHT (Feldspathic Highlands Terrane). Others, however, are not anorthosite-basalt mixtures. Three (17,75 ,/g Sm) consist mainly of nonmare mafic material from the nearside PKT (Procellarum KREEP Terrane) and a few are ternary mixtures of material from the FHT, PKT, and maria. Some contain mafic, nonmare lithologies like anorthositic norites, norites, gabbronorites, and troctolite. These breccias are largely unlike breccias of the Apollo collection in that they are poor in Sm as well as highly feldspathic anorthosite such as that common at the Apollo 16 site. Several have high Th/Sm compared to Apollo breccias. Dhofar 961, which is olivine gabbronoritic and moderately rich in Sm, has lower Eu/Sm than Apollo samples of similar Sm concentration. This difference indicates that the carrier of rare earth elements is not KREEP, as known from the Apollo missions. On the basis of our present knowledge from remote sensing, among lunar meteorites Dhofar 961 is the one most likely to have originated from South Pole-Aitken basin on the lunar far side. [source] Compositional and Failure Analysis of Polymers: A Practical Approach Edited by John Scheirs John Wiley & Sons Ltd, Chichester, 2000. pp xi,+,765, price £50.00 ISBN 0-471-62572-8POLYMER INTERNATIONAL, Issue 9 2001A Pethrick No abstract is available for this article. [source] Polymerization and matrix physical properties as important design considerations for soluble collagen formulationsBIOPOLYMERS, Issue 8 2010S. T. Kreger Abstract Despite extensive use of type I collagen for research and medical applications, its fibril-forming or polymerization potential has yet to be fully defined and exploited. Here, we describe a type I collagen formulation that is acid solubilized from porcine skin collagen (PSC), quality controlled based upon polymerization potential, and well suited as a platform polymer for preparing three-dimensional (3D) culture systems and injectable/implantable in vivo cellular microenvironments in which both relevant biochemical and biophysical parameters can be precision-controlled. PSC is compared with three commercial collagens in terms of composition and purity as well as polymerization potential, which is described by kinetic parameters and fibril microstructure and mechanical properties of formed matrices. When subjected to identical polymerization conditions, PSC showed significantly decreased polymerization times compared to the other collagens and yielded matrices with the greatest mechanical integrity and broadest range of mechanical properties as characterized in oscillatory shear, uniaxial extension, and unconfined compression. Compositional and intrinsic viscosity analyses suggest that the enhanced polymerization potential of PSC may be attributed to its unique oligomer composition. Collectively, this work demonstrates the importance of standardizing next generation collagen formulations based upon polymerization potential and provides preliminary insight into the contribution of oligomers to collagen polymerization properties. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 690,707, 2010. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Structural, Compositional and Electrochemical Characterization of Pt,Co Oxygen-Reduction CatalystsCHEMPHYSCHEM, Issue 7 2010S. Axnanda Abstract Pt,Co thin-film electrocatalysts have been characterized using low-energy ion-scattering spectroscopy (LEISS), X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), temperature-programmed desorption (TPD) and electrochemistry (EC). For comparative purposes, LEISS and EC were also carried out on a bulk Pt3Co(111) single crystal. The extensive experimental work resulted in the establishment of the surface phase diagram of the alloy film marked by a substantial divergence between the composition at the interface and that in the interior. When a dual-layer deposit of Pt and Co was annealed at high temperatures, alloy formation transpired in which the outermost layer became single-crystalline and enriched in Pt. The preferential surface segregation of Pt, however, was not sufficient to generate a platinum-only overlayer or "skin". Invariably, Co was found to co-exist with Pt, independent of the substrate [Mo(110) or Ru(0001)] employed; Pt3Co was the most favored composition. The same result, the absence of a Pt skin, was likewise indicated at the post-thermally-annealed surface of the bulk Pt3Co(111) monocrystal. For alloy-film surfaces more enriched in Pt than Pt3Co, the topmost layer was constituted primarily, but not exclusively, of Pt(111) domains. The proclivities of the alloys towards enhanced catalysis of the oxygen-reduction reaction were assessed in terms of their voltage efficiencies, as manifested by the open-circuit potential (OCP) in O2 -saturated sulfuric acid electrolyte. The Pt3Co surface, whether from the thin film or the bulk single crystal, exhibited the highest OCP, a significant improvement over pure Pt but still appreciably lower than the thermodynamic limit. The degradation of the Pt3Co thin-film surface was predominantly due to Co corrosion. A minimal amount was spontaneously dissolved upon simple immersion in solution; slightly higher dissolution occurred at potentials above the OCP. The fraction that was not immediately corroded proved to be stable even after prolonged periods at potentials more positive than the OCP. [source] Ecological boundary detection using Carlin,Chib Bayesian model selectionDIVERSITY AND DISTRIBUTIONS, Issue 6 2005Ralph Mac Nally ABSTRACT Sharp ecological transitions in space (ecotones, edges, boundaries) often are where ecologically important events occur, such as elevated or reduced biodiversity or altered ecological functions (e.g. changes in productivity, pollination rates or parasitism loads, nesting success). While human observers often identify these transitions by using intuitive or gestalt assignments (e.g. the boundary between a remnant woodland patch and the surrounding farm paddock seems obvious), it is clearly desirable to make statistical assessments based on measurements. These assessments often are straightforward to make if the data are univariate, but identifying boundaries or transitions using compositional or multivariate data sets is more difficult. There is a need for an intermediate step in which pairwise similarities between points or temporal samples are computed. Here, I describe an approach that treats points along a transect as alternative hypotheses (models) about the location of the boundary. Carlin and Chib (1995) introduced a Bayesian technique for comparing non-hierarchical models, which I adapted to compute the probabilities of each boundary location (i.e. a model) relative to the ensemble of models constituting the set of possible points of the boundary along the transect. Several artificial data sets and two field data sets (on vegetation and soils and on cave-dwelling invertebrates and microclimates) are used to illustrate the approach. The method can be extended to cases in with several boundaries along a gradient, such as where there is an ecotone of non-zero thickness. [source] Sedimentological, modal analysis and geochemical studies of desert and coastal dunes, Altar Desert, NW MexicoEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2007J. J. Kasper-Zubillaga Abstract Sedimentological, compositional and geochemical determinations were carried out on 54 desert and coastal dune sand samples to study the provenance of desert and coastal dunes of the Altar Desert, Sonora, Mexico. Grain size distributions of the desert dune sands are influenced by the Colorado River Delta sediment supply and wind selectiveness. The desert dune sands are derived mainly from the quartz-rich Colorado River Delta sediments and sedimentary lithics. The dune height does not exert a control over the grain size distributions of the desert dune sands. The quartz enrichment of the desert dune sands may be due to wind sorting, which concentrates more quartz grains, and to the aeolian activity, which has depleted the feldspar grains through subaerial collisions. The desert dune sands suffer from little chemical weathering and they are chemically homogeneous, with chemical alteration indices similar to those found in other deserts of the world. The desert sands have been more influenced by sedimentary and granitic sources. This is supported by the fact that Ba and Sr concentration values of the desert sands are within the range of the Ba and Sr concentration values of the Colorado River quartz-rich sediments. The Sr values are also linked to the presence of Ca-bearing minerals. The Zr values are linked to the sedimentary sources and heavy mineral content in the desert dunes. The Golfo de Santa Clara and Puerto Peñasco coastal dune sands are influenced by long shore drift, tidal and aeolian processes. Coarse grains are found on the flanks whereas fine grains are on the crest of the dunes. High tidal regimens, long shore drift and supply from Colorado Delta River sediments produce quartz-rich sands on the beach that are subsequently transported into the coastal dunes. Outcrops of Quaternary sedimentary rocks and granitic sources increase the sedimentary and plutonic lithic content of the coastal dune sands. The chemical index of alteration (CIA) values for the desert and coastal dune sands indicate that both dune types are chemically homogeneous. The trace element values for the coastal dune sands are similar to those found for the desert dune sands. However, an increase in Sr content in the coastal dune sands may be due to more CaCO3 of biogenic origin as compared to the desert dune sands. Correlations between the studied parameters show that the dune sands are controlled by sedimentary sources (e.g. Colorado River Delta sediments), since heavy minerals are present in low percentages in the dune sands, probably due to little heavy mineral content from the source sediment; grain sizes in the dune sands are coarser than those in which heavy minerals are found and/or the wind speed might not exert a potential entrainment effect on the heavy mineral fractions to be transported into the dune. A cluster analysis shows that the El Pinacate group is significantly different from the rest of the dune sands in terms of the grain-size parameters due to longer transport of the sands and the long distance from the source sediment, whereas the Puerto Peñasco coastal dune sands are different from the rest of the groups in terms of their geochemistry, probably caused by their high CaCO3 content and slight decrease in the CIA value. Copyright © 2006 John Wiley & Sons, Ltd. [source] Textural and compositional controls on modern beach and dune sands, New ZealandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 3 2007J. J. Kasper-Zubillaga Abstract Textural, compositional, physical and geophysical determinations were carried out on 111 beach and dune sand samples from two areas in New Zealand: the Kapiti,Foxton coast sourced by terranes of andesite and greywackes and the Farewell Spit,Wharariki coast sourced by a wide variety of Paleozoic terranes. Our aim is to understand how long-shore drift, beach width and source rock control the sedimentological and petrographic characteristics of beach and dune sands. Furthermore, this study shows the usefulness of specific minerals (quartz, plagioclase with magnetite inclusions, monomineralic opaque grains) to interpret the physical processes (fluvial discharges, long-shore currents, winds) that distribute beach and dune sands in narrow and wide coastal plains. This was done by means of direct (grain size and modal analyses) and indirect (specific gravity, magnetic/non-magnetic separations M/NM, magnetic susceptibility measurements, hysteresis loops) methods. Results are compared with beach sands from Hawaii, Oregon, the Spanish Mediterranean, Elba Island and Southern California. Compositionally, the Kapiti,Foxton sands are similar to first-order immature sands, which retain their fluvial signature. This results from the high discharge of rivers and the narrow beaches that control the composition of the Kapiti,Foxton sands. The abundance of feldspar with magnetite inclusions controls the specific gravity of the Kapiti,Foxton sands due to their low content of opaque minerals and coarse grain size. Magnetic susceptibility of the sands is related mainly to the abundance of feldspars with Fe oxides, volcanic lithics and free-opaque minerals. The Farewell Spit,Wharariki sands are slightly more mature than the Kapiti,Foxton sands. The composition of the Farewell Spit,Wharariki sands does not reflect accurately their provenance due to the prevalence of long-shore drift, waves, little river input and a wide beach. Low abundance of feldspar with magnetite inclusions and free opaque grains produces poor correlations between specific gravity (Sg) and Fe oxide bearing minerals. The small correlation between opaque grains and M/NM may be related to grain size. The magnetic susceptibility of Farewell Spit,Wharariki sands is low due to the low content of grains with magnetite inclusions. Hysteresis and isothermal remnant magnetization (IRM) agree with the magnetic susceptibility values. Copyright © 2006 John Wiley & Sons, Ltd. [source] The Thermal Decomposition of Three Magnetic Acetates at Their Autogenic Pressure Yields Different Products.EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2007Abstract We report on the one-stage, reproducible, solvent-free, competent and straightforward approach for the synthesis of fullerene-like Ni@C, Co@C, and Fe3O4@C core-shell nanostructures that can be scaled up. The single precursor reactions of low cost acetates of Fe, Co and Ni are separately conducted at a relatively low temperature (700 °C) in a closed Swagelok reactor, as compared to other methods for the formation of graphitic layers. It is worth mentioning that although identical reaction parameters are employed, using the three acetate precursors, the graphitic carbon is coated on nanosized metallic Ni and Co cores, while Fe tends to form Fe3O4, maintaining the same core-shell morphology. The systematic morphological, compositional, structural characterization and the room temperature magnetic susceptibility measurements of the as-made particles are carried out on a vibrating sample magnetometer. The plausible mechanism is based on the comparison between the dissociation products of three acetate precursors, their obtained experimental data, and calculations on the enthalpy and free energy changes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Structural studies of the capsular polysaccharide and lipopolysaccharide O-antigen of Aeromonas salmonicida strain 80204-1 produced under in vitro and in vivo growth conditionsFEBS JOURNAL, Issue 22 2004Zhan Wang Aeromonas salmonicida is a pathogenic aquatic bacterium and the causal agent of furunculosis in salmon. In the course of this study, it was found that when grown in vitro on tryptic soy agar, A. salmonicida strain 80204-1 produced a capsular polysaccharide with the identical structure to that of the lipopolysaccharide O-chain polysaccharide. A combination of 1D and 2D NMR methods, including a series of 1D analogues of 3D experiments, together with capillary electrophoresis-electrospray MS (CE-ES-MS), compositional and methylation analyses and specific modifications was used to determine the structure of these polysaccharides. Both polymers were shown to be composed of linear trisaccharide repeating units consisting of 2-acetamido-2-deoxy- d -galacturonic acid (GalNAcA), 3-[(N -acetyl-L-alanyl)amido]-3,6-dideoxy- d -glucose{3-[(N -acetyl- l -alanyl)amido]-3-deoxy- d -quinovose, Qui3NAlaNAc} and 2-acetamido-2,6-dideoxy- d -glucose (2-acetamido-2-deoxy- d -quinovose, QuiNAc) and having the following structure: [,3)- , - d -GalpNAcA-(1,3)- , - d -QuipNAc-(1,4)- , - d -Quip3NAlaNAc-(1-]n, where GalNAcA is partly presented as an amide and AlaNAc represents N -acetyl- l -alanyl group. CE-ES-MS analysis of CPS and O-chain polysaccharide confirmed that 40% of GalNAcA was present in the amide form. Direct CE-ES-MS/MS analysis of in vivo cultured cells confirmed the formation of a novel polysaccharide, a structure also formed in vitro, which was previously undetectable in bacterial cells grown within implants in fish, and in which GalNAcA was fully amidated. [source] Numerical modeling of hydrothermal zinc silicate and sulfide mineralization in the Vazante deposit, BrazilGEOFLUIDS (ELECTRONIC), Issue 2 2009M. S. APPOLD Abstract The Vazante zinc deposit in central Brazil is currently the world's largest known example of a hypogene nonsulfide (i.e. willemite-dominant) zinc deposit. The mineralization is hypothesized to have formed as a result of mixing between a hot, acidic, reducing, metal-rich brine and a cool, more basic and dilute, metal-poor meteoric fluid. The present study sought to investigate this scenario by quantifying the individual effects of temperature, pH, salinity, and oxidation state on willemite and sphalerite solubility, and modeling their combined effects during mixing through reaction path and reactive transport modeling. Solubility calculations showed that in an initially hot, moderately acidic, reducing, metal-rich ore fluid saturated with respect to silica, willemite solubility is relatively insensitive to changes in temperature and log , but highly sensitive to changes in pH and salinity. In contrast, sphalerite solubility was highly sensitive to changes in temperature and log , as well as salinity, and was less sensitive than willemite to changes in pH. Reaction path models sought to extend these observations by modeling the geochemistry of mixing. The results show that mixing is able to produce most of the major zinc ore and gangue minerals observed in the field, though not necessarily at the same paragenetic stages, and that both compositional and temperature changes from mixing are needed. Reactive transport models were formulated to investigate spatial patterns of mineralization. The results showed that sphalerite deposition was strongly controlled by temperature and concentrated in the regions of greatest temperature change. Willemite deposition was concentrated along the interface between the metal-rich ore fluid and the surrounding meteoric fluid. The more rapid transport of solute than heat, in conjunction with the higher concentration of silica than sulfide in both fluids meant that willemite mineralization developed over a broader region and in greater concentrations compared with sphalerite. [source] Combinatorial Hierarchically Ordered 2D Architectures Self-assembled from Nanocrystal Building Blocks,ADVANCED MATERIALS, Issue 19 2008Xiangxing Xu A one-step, low-cost, and general nanocrystal self-assembly method that covers both the nanometer-scale superlattice and macroscale ordered patterns,that is, hierarchical architectures,is developed. This approach can generate various functional, compositional, and dimensional combinatorial architectures. It may give new opportunities in applications of catalysis, electronics, energy, magnetic devices, and bio-techniques. [source] A Comparative Study of Galvanic Replacement Reactions Involving Ag Nanocubes and AuCl2, or AuCl4,,ADVANCED MATERIALS, Issue 13 2008Leslie Au Galvanic replacement of Ag nanocubes with AuCl2, and AuCl4, results in morphological, compositional, and spectral differences that provide insight into the reaction mechanism by which hollow/porous gold nanostructures can be prepared for biomedical applications. [source] Influence of composition on the biochemical and sensory characteristics of commercial Cheddar cheese of variable quality and fat contentINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 2 2007K N KILCAWLEY Ten commercial Cheddar cheeses of variable quality differing in fat content and age were subjected to compositional, proteolytic, lipolytic and sensory analyses. The compositional parameters of the full-fat cheeses were predominantly outside those typically associated with good-quality cheese. Sensory analysis discriminated the full-fat cheeses predominantly by age, with the longer ripened cheeses associated with more negative attributes, some which appeared to be due to excessive lipolysis and/or ,-casein breakdown. Both proteolysis and lipolysis appear to be age dependent. The two reduced-fat cheeses were clearly discriminated from the eight full-fat cheeses by sensory analysis that appeared to be due to differences in composition and the extent of lipolysis. [source] Sandstone diagenesis of the Lower Cretaceous Sindong Group, Gyeongsang Basin, southeastern Korea: Implications for compositional and paleoenvironmental controlsISLAND ARC, Issue 1 2008Yong Il Lee Abstract The Gyeongsang Basin is a non-marine sedimentary basin formed by extensional tectonism during the Early Cretaceous in the southeastern Korean Peninsula. The sediment fill starts with the Sindong Group distributed along the western margin of the basin. It consists of three lithostratigraphic units: the Nakdong (alluvial fan), Hasandong (fluvial) and Jinju (lacustrine) formations with decreasing age. Sindong Group sandstones are classified into four petrofacies (PF) based on their detrital composition: PF-A consists of the lower Nakdong Formation with average Q73F12R15; PF-B the upper Nakdong and lower Hasandong formations with Q66F15R18; PF-C the middle Hasandong to middle Jinju formations with Q49F29R22; and PF-D the upper Jinju Formation with Q26F34R41. The variations of detrital composition influenced the diagenetic mineral assemblage in the Sindong Group sandstones. Illite and dolomite/ankerite are important diagenetic minerals in PF-A and PF-B, whereas calcite and chlorite are dominant diagenetic minerals in PF-C and PF-D. Most of the diagenetic minerals can be divided into early and late diagenetic stages of formation. Early diagenetic calcites occur mostly in PF-C, probably controlled by arid to semiarid climatic conditions during the sandstone deposition, no early calcite being found in PF-A and PF-B. Late-stage calcites are present in all Sindong Group sandstones. The calcium ions may have been derived from shale diagenesis and dissolution of early stage calcites in the Hasandong and Jinju sandstones. Illite, the only diagenetic clay mineral in PF-A and lower PF-B, is inferred to be a product of kaolinite transformation during deep burial, and the former presence of kaolinite is inferred from the humid paleoclimatic conditions during the deposition of the Nakdong Formation. Chlorites in PF-C and PF-D are interpreted to be the products of transformation of smectitic clay or of precipitation from alkaline pore water under arid to semiarid climatic conditions. The occurrence of late-stage diagenetic minerals largely depended on the distribution of early diagenetic minerals, which was controlled initially by the sediment composition and paleoclimate. [source] The development of vegetative zonation patterns in restored prairie pothole wetlandsJOURNAL OF APPLIED ECOLOGY, Issue 1 2003Eric W. Seabloom Summary 1The spatial structure of plant communities can have strong impacts on ecosystem functions and on associated animal communities. None the less, spatial structure is rarely used as a measure of restoration success. 2The restoration of hundreds of wetlands in the prairie pothole region in the mid-western USA provided an excellent opportunity to determine whether the re-establishment of abiotic conditions is sufficient to restore structure, composition and spatial patterning of the vegetation. 3We mapped the topography and vegetative distributions in 17 restored and nine natural wetlands. We used these data to compare the composition and spatial structure of the vegetation in both wetlands types. 4The composition of the plant communities differed between restored and natural wetlands; the restored wetlands lacked the well-developed sedge-meadow community found in most natural wetlands. However, the spatial heterogeneity was similar, although the zonation patterns were less well-developed in the restored wetlands. 5Although the overall structure was similar, species distributions differed among wetland types, such that species were found more than 10 cm higher in restored wetlands than in natural wetlands. 6Synthesis and applications. This study illustrates that restored plant community composition and spatial structure may converge on their targets at different rates. Evaluations of restoration success should consider spatial structure of communities along with compositional and functional metrics. [source] Phlogopite and quartz lamellae in diamond-bearing diopside from marbles of the Kokchetav massif, Kazakhstan: exsolution or replacement reaction?JOURNAL OF METAMORPHIC GEOLOGY, Issue 9 2009L. F. DOBRZHINETSKAYA Abstract Exsolution lamellae of pyroxene in garnet (grt), coesite in titanite and omphacite from UHPM terranes are widely accepted as products of decompression. However, interpretation of oriented lamellae of phyllosilicates, framework silicates and oxides as a product of decompression of pyroxene is very often under debate. Results are presented here of FIB-TEM, FEG-EMP and synchrotron-assisted infrared (IR) spectroscopy studies of phlogopite (Phlog) and phlogopite + quartz (Qtz) lamellae in diamond-bearing clinopyroxene (Cpx) from ultra-high pressure (UHP) marble. These techniques allowed collection of three-dimensional information from the grain boundaries of both the single (phlogopite), two-phase lamellae (phlogopite + quartz), and fluid inclusions inside of diamond included in K-rich Cpx and understanding their relationships and mechanisms of formation. The Cpx grains contain in their cores lamellae-I, which are represented by topotactically oriented extremely thin lamellae of phlogopite (that generally are two units cell wide but locally can be seen to be somewhat broader) and microdiamond. The core composition is: (Ca0.94K0.04Na0.02) (Al0.06Fe0.08Mg0.88) (Si1.98Al0.02)O6.00. Fluid inclusions rich in K and Si are recognized in the core of the Cpx, having no visible connections to the lamellae-I. Lamellar-II inclusions consist of micron-size single laths of phlogopite and lens-like quartz or slightly elongated phlogopite + quartz intergrowths; all are situated in the rim zone of the Cpx. The composition of the rim is (Ca0.95Fe0.03Na0.02) (Al0.05Fe0.05Mg0.90)Si2O6, and the rim contains more Ca, Mg then the core, with no K there. Such chemical tests support our microstructural observations and conclusion that the phlogopite lamellae-I are exsolved from the K-rich Cpx-precursor during decompression. It is assumed that Cpx-precursor was also enriched in H2O, because diamond included in the core of this Cpx contains fluid inclusions. The synchrotron IR spectra of such diamond record the presence of OH, stretching and H2O bending motion regions. Lamellar-II inclusions are interpreted as forming partly because of modification of the lamellae-I in the presence of fluid enriched in K, Fe and Si during deformation of the host diopside; the latter is probably related to the shallower stage of exhumation of the UHP marble. This study emphasizes that in each case to understand the mechanism of lamellar inclusion formation more detailed studies are needed combining both compositional, structural and three-dimensional textural features of lamellar inclusions and their host. [source] Microstructural tectonometamorphic processes and the development of gneissic layering: a mechanism for metamorphic segregationJOURNAL OF METAMORPHIC GEOLOGY, Issue 1 2000Williams The Mary granite, in the East Athabasca mylonite triangle, northern Saskatchewan, provides an example and a model for the development of non-migmatitic gneissic texture. Gneissic compositional layering developed through the simultaneous evolution of three microdomains corresponding to original plagioclase, orthopyroxene and matrix in the igneous rocks. Plagioclase phenocrysts were progressively deformed and recrystallized, first into core and mantle structures, and ultimately into plagioclase-rich layers or ribbons. Garnet preferentially developed in the outer portions of recrystallized mantles, and, with further deformation, produced garnet-rich sub-layers within the plagioclase-rich gneissic domains. Orthopyroxene was replaced by clinopyroxene and garnet (and hornblende if sufficient water was present), which were, in turn, drawn into layers with new garnet growth along the boundaries. The igneous matrix evolved through a number of transient fabric stages involving S-C fabrics, S-C-C, fabrics, and ultramylonitic domains. In addition, quartz veins were emplaced and subsequently deformed into quartz-rich gneissic layers. Moderate to highly strained samples display extreme mineralogical (compositional) segregation, yet most domains can be directly related to the original igneous precursors. The Mary granite was emplaced at approximately 900 °C and 1.0 GPa and was metamorphosed at approximately 750 °C and 1.0 GPa. The igneous rocks crystallized in the medium-pressure granulite field (Opx,Pl) but were metamorphosed on cooling into the high-pressure (Grt,Cpx,Pl) granulite field. The compositional segregation resulted from a dynamic, mutually reinforcing interaction between deformation, metamorphic and igneous processes in the deep crust. The production of gneissic texture by processes such as these may be the inevitable result of isobaric cooling of igneous rocks within a tectonically active deep crust. [source] Compositional and configurational sequence determination of methyl methacrylate/ethyl acrylate copolymers by one- and two-dimensional nuclear magnetic resonance spectroscopyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2003A. S. Brar Abstract Ethyl acrylate (E)/methyl methacrylate (M) copolymers of different compositions were prepared, and their compositions were determined with 1H NMR spectra. The complete spectral assignments, in terms of the compositional and configurational sequences of these copolymers, were made with the help of distortionless enhancement by polarization transfer and two-dimensional heteronuclear single quantum coherence spectroscopy. The ,-(CH3)M, CH (E), CH2, and ,CO carbons of both M and E units were found to be sensitive to various compositional and configurational sequences. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 313,326, 2003 [source] Raman microscopy of the mixite mineral BiCu6(AsO4)3(OH)6·3H2O from the Czech RepublicJOURNAL OF RAMAN SPECTROSCOPY, Issue 5 2010Ray L. Frost Abstract Raman microscopy of the mixite mineral BiCu6(AsO4)3(OH)6·3H2O from Jáchymov and from Smrkovec (both Czech Republic) has been used to study their molecular structure. The presence of (AsO4)3,, (AsO3OH)2,, (PO4)3, and (PO3OH)2, units, as well as molecular water and hydroxyl ions, was inferred. OH···O hydrogen bond lengths were calculated from the Raman and infrared spectra using Libowitzky's empirical relation. Small differences in the Raman spectra between both samples were observed and attributed to compositional and hydrogen-bonding network differences. Copyright © 2009 John Wiley & Sons, Ltd. [source] RELATIONSHIPS BETWEEN SENSORY AND RHEOLOGICAL MEASUREMENTS OF TEXTURE IN MATURING COMMERCIAL CHEDDAR CHEESE OVER A RANGE OF MOISTURE AND pH AT THE POINT OF MANUFACTUREJOURNAL OF TEXTURE STUDIES, Issue 4 2006C.D. EVERARD ABSTRACTS Textural characteristics of 10 Cheddar cheeses with a range of moisture contents and pH values were investigated by sensory and instrumental methods, over a 9-month maturing period. A trained panel of nine assessors described the sensory texture characteristics of the cheeses using 11 texture parameters. Instrumental parameters were derived using texture profile analysis. Relationships between sensory, instrumental, compositional and maturation properties of the cheeses were determined with the aid of principal component analysis and multiple linear regression. Nine sensory parameters significantly correlated with instrumental parameters, e.g., sensory rubbery correlated with instrumental firmness (R = 0.696, P < 0.001), chewiness (R = 0.679, P < 0.001), fracture stress (R = 0.669, P < 0.001) and springiness (R = 0.643, P < 0.001). Sensory firmness corresponded closely with instrumental firmness (R = 0.539, P < 0.001) and fracture stress (R = 0.518, P < 0.001). Sensory and instrumental texture parameters were significantly affected by changes in moisture content, pH and maturation. [source] Formation Kinetics of a Bi3Nb1,xTaxO7 Fluorite-Type Solid Solution and Thermodynamic Stability of the Bi3TaO7 End MemberJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Ursa Pirnat Analysis of kinetic characteristics of the incommensurate,commensurate transformation in the Bi3Nb1,xTaxO7 system with a fluorite-like crystal structure enabled us to define the compositional and thermal stability ranges of the commensurate tetragonal polymorph. We showed that the tetragonal polymorph across the entire homogeneity range is isostructural to the Bi3NbO7 end member. The kinetics of the transformation from the cubic incommensurate to the tetragonal commensurate phase decreases with an increase in Ta concentration within the Bi3Nb1,xTaxO7 system. The formation studies indicate that the tetragonal Bi3TaO7 is thermodynamically stable; however, its formation via the metastable incommensurate-cubic phase is suppressed. [source] Effect of fat replacers on kefir qualityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2010Bilge Ertekin Abstract The purpose of the study was to determine the effects of fat replacers on the quality of non-fat kefir. Skim milk fortified with Dairy Lo® (DL) and inulin (INU) was fermented with kefir grains to manufacture kefir. The results of compositional, microbiological, rheological and sensorial analyses were compared with whole kefir (WK) and non-fat kefir (NFK) controls. Results for dry matter, pH and lactic acid ranged between 82.4 and 109.1 g kg,1, 4.26 and 4.40, and 7.0 and 9.2 g L,1, respectively. Acetaldehyde and ethanol contents of samples were between 2.89 and 7.28 mg L,1, and 151.46 and 323.89 mg L,1, respectively. In all samples, Lactobacillus spp., Streptococcus spp. and yeast counts were between 9.1 and 9.9, 9.3 and 9.9, and 5.2 and 5.6 log cfu mL,1, respectively. Kefir samples had non-Newtonian behaviour and pseudoplastic fluid with thixotropy. At the first day, DL had the highest apparent viscosity (3.119 Pa s) while NFK had the lowest value (1.830 Pa s). In the sensory evaluation, odour and taste scores of samples were not different. Dairy Lo® and inulin could be used without any adverse effect for the production of non-fat kefir. Copyright © 2009 Society of Chemical Industry [source] Quality characteristics of a non-fermented dry-cured sausage formulated with lemon albedoJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2004Luis Aleson-Carbonell Abstract Dry-cured sausages were treated with two types of dehydrated lemon albedo (raw and cooked) at five concentrations (0,100 g kg,1 in 25 g kg,1 increments). Several physical and chemical analyses were made during the drying stage, and compositional, textural and sensory analyses were conducted on the finished products. The addition of albedo improved the nutritional properties as a result of fibre addition and may have beneficial effects due to the presence of active biocompounds as evidenced by a decrease in residual nitrite levels and delayed oxidation (based on TBARS values). The sensory properties of samples that resembled the control sausages were those that contained up to 50 g kg,1 dehydrated raw albedo and 75 g kg,1 dehydrated cooked albedo. Copyright © 2004 Society of Chemical Industry [source] Influence of composition and structure of oil-in-water emulsions on retention of aroma compoundsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2002Dr Saskia M van Ruth Abstract The influence of the composition and structure of oil-in-water emulsions on aroma retention was examined for 20 volatile compounds. Compositional and structural parameters included the fraction of emulsifier phase, the fraction of lipid phase and the particle size distribution of the dispersed lipid phase in the emulsion. Air/liquid partition coefficients of dimethyl sulphide, 1-propanol, diacetyl, 2-butanone, ethyl acetate, 1-butanol, 2-pentanol, propyl acetate, 3-methyl-1-butanol, ethyl butyrate, hexanal, butyl acetate, 1-hexanol, 2-heptanone, heptanal, ,-pinene, 2-octanone, octanal, 2-nonanol and 2-decanone were determined by static headspace gas chromatography. The hydrophobicity of the compounds determined the influence of the compositional and structural parameters of the emulsions on air/liquid partitioning. Increase of the emulsifier fraction increased the retention of mainly hydrophilic aroma compounds and decreased the retention of hydrophobic compounds. Higher lipid levels led to increased retention of hydrophobic compounds and release of hydrophilic compounds. Emulsions with larger particles showed increased aroma retention, which was independent of the lipid fraction and the polarity of the aroma compounds. The data demonstrated a profound effect of both composition and structure of oil-in-water emulsions on the air/liquid partitioning of the 20 aroma compounds under equilibrium conditions. © 2002 Society of Chemical Industry [source] Fire disturbance and forest structure in old-growth mixed conifer forests in the northern Sierra Nevada, CaliforniaJOURNAL OF VEGETATION SCIENCE, Issue 6 2007R. Matthew Beaty Abstract Question: This study evaluates how fire regimes influence stand structure and dynamics in old-growth mixed conifer forests across a range of environmental settings. Location: A 2000-ha area of mixed conifer forest on the west shore of Lake Tahoe in the northern Sierra Nevada, California. Methods: We quantified the age, size, and spatial structure of trees in 12 mixed conifer stands distributed across major topographic gradients. Fire history was reconstructed in each stand using fire scar dendrochronology. The influence of fire on stand structure was assessed by comparing the fire history with the age, size, and spatial structure of trees in a stand. Results: There was significant variation in species composition among stands, but not in the size, age and spatial patterning of trees. Stands had multiple size and age classes with clusters of similar aged trees occurring at scales of 113 - 254 m2. The frequency and severity of fires was also similar, and stands burned with low to moderate severity in the dormant season on average every 9,17 years. Most fires were not synchronized among stands except in very dry years. No fires have burned since ca. 1880. Conclusions: Fire and forest structure interact to perpetuate similar stand characteristics across a range of environmental settings. Fire occurrence is controlled primarily by spatial variation in fuel mosaics (e.g. patterns of abundance, fuel moisture, forest structure), but regional drought synchronizes fire in some years. Fire exclusion over the last 120 years has caused compositional and structural shifts in these mixed conifer forests. [source] | |||||||||||||||||||||||||||||||||||||||||||