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Kinds of Chemical Terms modified by Chemical Selected AbstractsPHYSICAL, CHEMICAL, and THERMAL CHARACTERIZATION of WHEAT FLOUR MILLING COPRODUCTS,,JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2003Y.S. KIM ABSTRACT Hard red winter (HRW) and hard red spring (HRS) wheat milling coproducts (bran, germ, shorts, and red dog) from three commercial flour mills and the Kansas State University pilot mill were evaluated for differences in physical, chemical, and thermal properties. the ranges of bulk density for bran, germ, and red dog determined at three moisture levels were 146.5 to 205.2 kgm,3, 269.2 to 400.6 kgm,3, and 298.9 to 398.1 kgm,3, respectively. the true density ranking order was: red dog >shorts = germ >bran, independently of the moisture level. Red dog had the smallest geometrical mean diameter with the highest variation (coefficient of variation of 23.8%). There was a significant (P < 0.05) difference among wheat blends and milling flows in the thickness of bran and germ at the same particle separation size. the image analysis study determined that the equivalent projected area diameter of bran at the same separation size was significantly (P < 0.05) larger than that of germ. the ratio between the equivalent projected area diameter and the particle thickness were within ranges of 15.7 to 37.6 for bran and 15.5 to 32.2 for germ particles. the chemical composition (ash, protein, lipids and fiber) ranges were determined for each coproduct. Ranges of thermal conductivity for bran, germ, shorts, and red dog were 0.049 to 0.074, 0.054 to 0.0907, 0.057 to 0.076, and 0.063 to 0.080 W(mK),1, respectively. Specific heat of coproducts, measured with a differential scanning calorimeter, exhibited a wider range [1.08,1.94 kJ(kgK),1] than that observed in whole wheat kernels and wheat flour. the variability observed among the samples was due to the different wheat sources and characteristic milling flows for the flour mills. [source] MICROBIAL, CHEMICAL AND PHYSICAL CHANGES IN CHILL WATER TREATED WITH ELECTROCHEMICAL METHODJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2000LI MA ABSTRACT A three-zone (anode, neutral, and cathode) electrochemical treatment chamber was designed and built to evaluate the inactivation of Salmonella typhimurium in poultry chill water. The chill water in the three-zone chamber containing ,106 CFU/mL S. typhimurium and 0.5% or 1.0% NaCl was treated at 15 or 25 mA/cm2, and a temperature of 5,10C for up to 10 min. The Salmonella were inactivated within 0.5 to 4 min in the anode zone depending on the salt concentration and current density, slower inactivation rate in the cathode zone, and almost no inactivation in the neutral zone. The pH decreased to , 2 in anode zone, but increased to , 10 in the cathode zone. Temperature increased by 2,6.5C in the three zones depending on current density and salt concentration. The conductivity increased in the anode and cathode zones but little change in the neutral zone. The generated chlorine was proportional to the current density and the treatment time. [source] EFFECTS OF COOKING AND DRYING PROCESSES ON PHYSICAL, CHEMICAL AND SENSORY PROPERTIES OF LEGUME BASED BULGURJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2009NERMIN BILGIÇLI ABSTRACT The changes in physical, chemical and sensory properties of common bean (CB) and chickpea (CP) bulgur prepared with different cooking (atmospheric, pressure and microwave) and drying (oven at 60, 70 and 80C; microwave at 350 and 700 W) processes were investigated. Neither the cooking methods nor the drying methods significantly affected the ash and protein contents of CB and CP bulgur. Pressure cooking gave lower phytate phosphorus and higher bulgur yield and volume increase values when compared to the other cooking methods. Average bulgur yields were found as 82% for CB and 84% for CP. Cooking processes decreased the phytic acid content of the bulgurs between 25.2 and 39.5% according to raw legume. Ca, K, Mg, P, Zn, Cu and Fe contents of the bulgurs decreased in variable degrees (8.69,28.5%) when compared to raw materials. Pressure cooked and oven (80C) dried bulgur samples in the case of bulgur pilaf were appreciated by the panelists in terms of overall acceptability. PRACTICAL APPLICATIONS Bulgur is a valuable cereal product with its high nutritional value and long shelf life. In this research, bulgur process was applied successfully on common bean and chickpea, and new legume-based bulgur products improved. The bulgur yield (BY) of the legumes was above 80%. Pressure cooking increased the nutritional, sensory and technological quality of the legume bulgurs. [source] COMPARISON OF VOLATILE COMPOUNDS AND CHEMICAL AND PHYSICAL PROPERTIES IN ORANGE JUICE FROM DIFFERENT PARTS OF JINCHEN FRUITJOURNAL OF FOOD QUALITY, Issue 2 2010YU QIAO ABSTRACT Jinchen is a native sweet cultivar of Citrus sinensis and one of the most important varieties used in orange juice processing in China. The study of flavor components of Jinchen orange juice has not been carried out before. In this paper, the color characteristics, pH value, total soluble solids, total acids, as well as organic acids and sugars were determined in Jinchen orange juice from different parts of fruit (peeled juice, pulp juice, whole fruit juice). The color characteristics were significantly different among three types of Jinchen orange juice. The level of vitamin C and total soluble solids/total acids ratio (TSS/TA) is higher in whole fruit juice. The organic acids and sugars also changed. Pulp juice is rich in the highest amounts of organic acids and sugars. Volatiles from three juices were studied using the solid phase microextraction (SPME) combined with gas chromatography/mass spectrometry. The whole fruit juice has the highest amount of volatile compounds (53.07 mg/L) followed by peeled juice (51.044 mg/L) and pulp juice (27.107 mg/L). Some differences in the constituents of the volatile compounds of three type juices were observed. These results indicated that volatile compounds and quality properties differed in Jinchen orange juice from different parts of fruit. PRACTICAL APPLICATIONS The peeled orange fruits are usually used for juice processing. Great amounts of aroma components with intensive odor are located in the peel of orange. The aroma of pulp possessing weak fresh citrus odor is different from peel. The different parts of the orange utilized in processing have direct impact on juice quality. It is very essential to obtain the data of chemical and physical properties in juice from different parts of orange fruit. The quality information could be used to modify the orange aroma. [source] PHYSICAL, CHEMICAL AND SENSORY QUALITY OF MICROWAVE-BLANCHED SNOW PEASJOURNAL OF FOOD QUALITY, Issue 6 2001S. BEGUM ABSTRACT Snow peas were blanched using four methods [conventional boiling water (BW); steam (ST); microwave (MW); and microwave blanched in heat sealable bags (MWB)], then held frozen at (,18C) for four weeks. Immediately after blanching, MWB-blanched snow peas retained more reduced ascorbic acid (RAA; 72%), than other treatments. Blanching treatment had no effect on lightness [L* value). With the exception of BW-blanched peas, blanching significantly altered color. After frozen storage, MWB- and MW-blanched samples both contained about 26 mg/100 g RAA, significantly more RAA than other treatments. MWB-blanched peas generally had as high or higher sensory appearance, aroma, flavor, texture and general acceptability scores than other treatments. These results imply that blanching snow peas in a heat-sealable microwave bag, prior to frozen storage, produces a product of equivalent sensory quality and superior nutritional quality compared with more conventional blanching methods. [source] CHANGES IN CHEMICAL, SENSORY AND RHEOLOGICAL CHARACTERISTICS OF MANCHEGO CHEESES DURING RIPENINGJOURNAL OF SENSORY STUDIES, Issue 4 2001MIGUEL ANGEL GONZÁLEZ-VIŃAS ABSTRACT Manchego cheese is a high-fat pressed ewe's-milk cheese made in Castilla-La Mancha (Spain) and produced by enzymatic coagulation. The minimum ripening time before marketing required by the Regulatory Board of the Manchego Cheese Appellation of Origin is 60 days. This paper describes the physicochemical, proteolysis, sensory and texture characteristics of Manchego cheese, and the degree of homogeneity of cheeses made under the Manchego Appellation of Origin. The data gathered in this study indicate that sensory and instrumental analysis are useful tools for detecting changes in Manchego cheese during ripening. These changes were first detected by the instrumental analysis (2 months). The panelists detected differences after 4 months' ripening in all the factories. With physicochemical analysis, on the other hand, longer ripening times (6,8 months) are required before such changes become appreciated. [source] ARCHAEOMETRICAL INVESTIGATION OF SICILIAN EARLY BYZANTINE GLASS: CHEMICAL AND SPECTROSCOPIC DATA*ARCHAEOMETRY, Issue 1 2010R. ARLETTI A series of early Byzantine glasses, recovered in Ganzirri (Sicily, Italy), was analysed for major, minor and trace elements. All the analysed fragments were found to be natron-based silica,lime glass. Concerning minor and trace elements, the samples can be divided into two groups: glass with high Fe, Ti and Mn contents (HIMT glass) and glass with low levels of Fe, Ti and Mn. These results, strictly in agreement with literature data for glass of the Mediterranean region, can be interpreted as a consequence of the wide trade network established in this region and of the intense circulation of raw glass and artefacts from different Mediterranean areas. X-ray absorption spectroscopy studies at Fe and Mn K-edges, performed on HIMT glass, indicate that Fe is in the oxidized form while Mn is in the reduced form. [source] CHEMICAL AND PHYSICAL CHARACTERIZATION OF STUCCOS FROM A MEXICAN COLONIAL BUILDING: EL MUSEO DEL CALENDARIO OF QUERETARO*ARCHAEOMETRY, Issue 5 2009MIGUEL GALVÁN-RUIZ Restoration requires the use of appropriate characterization methods and suitable new material preparation processes permit the reproduction of the original material to be as similar as possible in order to be an appropriate application method. The combination of these factors will facilitate a good restoration process. Different stuccos were taken from El Museo del Calendario, a building located in Querétaro, Mexico which was built in the 16th century. All the stucco samples were studied using the characterization process which is proposed in this article. The characterization method consisted of the use of analytical techniques, such as X-ray diffraction, Fourier transform infrared and scanning electron microscopy. This characterization method made reproduction of the original material possible. The new material combined with new application techniques developed in situ will result in a high-quality restoration process. [source] CHEMICAL,MINERALOGICAL ANALYSES AND MICROSTRUCTURAL STUDIES OF PREHISTORIC POTTERY FROM RAHMATABAD, SOUTH-WEST IRAN*ARCHAEOMETRY, Issue 5 2009A. K. MARGHUSSIAN A series of prehistoric pottery samples excavated from Rahmatabad, south-west Iran, were investigated using XRF and XRD analyses to determine their chemical and mineralogical compositions. The sample microstructures were also studied by SEM/EDX. The relative similarity of compositions, the fine, dense and homogeneous microstructures and the presence of high-temperature phases such as diopside and mullite showed the use of high firing temperatures, in the range 950,1050°C. This, along with the homogeneity in shape, decoration and size ranges of the ware, all indicate the adoption of specialized pottery-making techniques by the potters of Rahmatabad in the fifth to fourth millennia bc. [source] A COMPARISON OF THE CHEMICAL AND ENGINEERING CHARACTERISTICS OF ANCIENT ROMAN HYDRAULIC CONCRETE WITH A MODERN REPRODUCTION OF VITRUVIAN HYDRAULIC CONCRETE*ARCHAEOMETRY, Issue 4 2008E. GOTTI The authors have completed structural and compositional analysis of Roman hydraulic concrete using large cores taken from a variety of maritime structures. In 2005 an 8 m3 block of hydraulic, pozzolanic concrete was built in the sea at Brindisi (Italy), applying the materials and procedures specified by the Roman architect Vitruvius. Cores were taken at 6 months and 12 months after construction and subjected to the same analyses as the first-century bc cores from pilae associated with the Villa of the Domitii Ahenobarbi at Santa Liberata. Results show that a slight variation on the Vitruvian formula yields results closest to the Roman material, and that substantial curing requires 12 months. [source] CLAY RESOURCES AND TECHNICAL CHOICES FOR NEOLITHIC POTTERY (CHALAIN, JURA, FRANCE): CHEMICAL, MINERALOGICAL AND GRAIN-SIZE ANALYSES*ARCHAEOMETRY, Issue 1 2007R. MARTINEAU Many authors have considered pottery manufacturing constraints and sociocultural elements as factors in change in past civilizations over time. The main issue of this research is to better understand the reasons for changes, or choices, in pottery raw materials. The very precise and detailed stratigraphy and cultural succession of occupations is based on dendrochronological data from the lake-dwelling sites of Chalain (Jura, France). Petrographic, palaeontological and chemical analyses were used to determine the nature and origins of the raw materials used by the Neolithic potters. Stratigraphy and dendrochronological data were used to reconstruct in detail the evolution dynamics of fabric changes. Several raw material sources were identified for many of the pottery groups. Each of them was sampled for qualitative experimental tests of pottery forming. The experimental results show a high variability between the sediments tested. This variability was quantitatively estimated by XRF, XRD, the Rietveld method, calcium carbonate quantification and laser grain-size analyses of matrices, indirect measures of plasticity. These analytical results allow a better understanding of the differences observed in the experimental tests. On the basis of these experimental and analytical results, changing parameters such as pottery manufacturing constraints, mineralogical characteristics of raw materials and sociocultural factors are considered. In conclusion, all the social and technical parameters, in each archaeological context, must be taken into account for a better understanding of the changes occurring throughout the chronological sequence. [source] Electrochemical, Chemical and Enzymatic Oxidations of PhenothiazinesELECTROANALYSIS, Issue 17 2005B. Blankert Abstract The oxidation of several phenothiazine drugs (phenothiazine, promethazine hydrochloride, promazine hydrochloride, trimeprazine hydrochloride and ethopropazine hydrochloride) has been carried out in aqueous acidic media by electrochemical, chemical and enzymatic methods. The chemical oxidation was performed in acetic acid with hydrogen peroxide or in formate buffers using persulfate. The enzymatic oxidation was performed in acetate or ammonium formate buffer by the enzyme horseradish peroxidase in the presence of H2O2. Molecules with, in the lateral chain, two carbon atoms (2C) separating the ring nitrogen and the terminal nitrogen, showed two parallel oxidation pathways, that is (i) formation of the corresponding sulfoxide and (ii) cleavage of the lateral chain with liberation of phenothiazine (PHZ) oxidized products (PHZ sulfoxide and PHZ quinone imine). Molecules with three carbon atoms (3C) separating the two nitrogens were oxidized to the corresponding sulfoxide. The chemical oxidation of all the studied molecules by hydrogen peroxide resulted in the corresponding sulfoxide with no break of the lateral chain. Oxidation by persulfate yielded, for the 3C derivatives, only the corresponding sulfoxide, but it produced cleavage of the lateral chain for the 2C derivatives. The origin of the distinct oxidation pattern between 2C and 3C molecules might be related to steric effects due to the lateral chain. The data are of interest in drug metabolism studies, especially for the early search. In the case of 2C phenothiazines, the results predict the possibility of an in vivo cleavage of the lateral chain with liberation of phenothiazine oxidized products which are known to produce several adverse side effects. [source] Targeting Chemical and Biological Warfare Agents at the Molecular LevelELECTROANALYSIS, Issue 14 2003Omowunmi Abstract After the September,11 tragedies of 2001, scientists and law-enforcement agencies have shown increasing concern that terrorist organizations and their "rogue" foreign government-backers may resort to the use of chemical and/or biological agents against U.S. military or civilian targets. In addition to the right mix of policies, including security measures, intelligence gathering and training for medical personnel on how to recognize symptoms of biochemical warfare agents, the major success in combating terrorism lies in how best to respond to an attack using reliable analytical sensors. The public and regulatory agencies expect sensing methodologies and devices for homeland security to be very reliable. Quality data can only be generated by using analytical sensors that are validated and proven to be under strict design criteria, development and manufacturing controls. Electrochemical devices are ideally suited for obtaining the desired analytical information in a faster, simpler, and cheaper manner compared to traditional (lab-based) assays and hence for meeting the requirements of decentralized biodefense applications. This articler presents a review of the major trends in monitoring technologies for chemical and biological warfare (CBW) agents. It focuses on research and development of sensors (particularly electrochemical ones), discusses how advances in molecular recognition might be used to design new multimission networked sensors (MULNETS) for homeland security. Decision flow-charts for choosing particular analytical techniques for CBW agents are presented. Finally, the paths to designing sensors to meet the needs of today's measurement criteria are analyzed. [source] Cover Picture: Electrophoresis 14'09ELECTROPHORESIS, Issue 14 2009Article first published online: 28 JUL 200 Issue no. 14 is an Emphasis Issue with 9 articles on various aspects of "Proteins and Proteomics" while the remaining 14 articles are arranged into 4 different parts including "Microfluidics and Miniaturization", "Genotyping and Transcriptomics", "Enantioseparations", and "Nanoparticles and Abused Drugs Analyses". Selected articles are: Effective elimination of nucleic acids from bacterial protein samples for optimized blue native polyacrylamide gel electrophoresis ((10.1002/elps.200900026)) 2-D difference in gel electrophoresis combined with Pro-Q Diamond staining: A successful approach for the identification of kinase/phosphatase targets ((10.1002/elps.200800780)) Microvalves actuated sandwich immunoassay on an integrated microfluidic system ((10.1002/elps.200800818)) Chemical gradient-mediated melting curve analysis for genotyping of SNPs ((10.1002/elps.200800729)) [source] Assessing sediment contamination in estuariesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2001Peter M. Chapman Abstract Historic and ongoing sediment contamination adversely affects estuaries, among the most productive marine ecosystems in the world. However, all estuaries are not the same, and estuarine sediments cannot be treated as either fresh or marine sediments or properly assessed without understanding both seasonal and spatial estuarine variability and processes, which are reviewed. Estuaries are physicochemically unique, primarily because of their variable salinity but also because of their strong gradients in other parameters, such as temperature, pH, dissolved oxygen, redox potential, and amount and composition of particles. Salinity (overlying and interstitial) varies spatially (laterally, vertically) and temporally and is the controlling factor for partitioning of contaminants between sediments and overlying or interstitial water. Salinity also controls the distribution and types of estuarine biota. Benthic infauna are affected by interstitial salinities that can be very different than overlying salinities, resulting in large-scale seasonal species shifts in salt wedge estuaries. There are fewer estuarine species than fresh or marine species (the paradox of brackish water). Chemical, toxicological, and community-level assessment techniques for estuarine sediment are reviewed and assessed, including chemistry (grain size effects, background enrichment, bioavailability, sediment quality values, interstitial water chemistry), biological surveys, and whole sediment toxicity testing (single-species tests, potential confounding factors, community level tests, laboratory-to-field comparisons). Based on this review, there is a clear need to tailor such assessment techniques specifically for estuarine environments. For instance, bioavailability models including equilibrium partitioning may have little applicability to estuarine sediments, appropriate reference comparisons are difficult in biological surveys, and there are too few full-gradient estuarine sediment toxicity tests available. Specific recommendations are made to address these and other issues. [source] Chemical and faecal ,scalding'EQUINE VETERINARY EDUCATION, Issue 2 2005R. C. Pilsworth No abstract is available for this article. [source] Predator Inspection Behaviour in a Characin Fish: an Interaction between Chemical and Visual Information?ETHOLOGY, Issue 9 2003Grant E. Brown Recent evidence suggests that predator inspection behaviour by Ostariophysan prey fishes is regulated by both the chemical and visual cues of potential predators. In laboratory trials, we assessed the relative importance of chemical and visual information during inspection visits by varying both ambient light (visual cues) and predator odour (chemical cues) in a 2 × 2 experimental design. Shoals of glowlight tetras (Hemigrammus erythrozonus) were exposed to a live convict cichlid (Archocentrus nigrofasciatus) predator under low (3 lux) or high (50 lux) light levels and in the presence of the odour of a cichild fed tetras (with an alarm cue) or swordtails (Xiphophorus helleri, with an alarm cue not recognized by tetras). Tetras exhibited threat-sensitive inspection behaviour (increased latency to inspect, reduced frequency of inspection, smaller inspecting group sizes and increased minimum approach distance) towards a predator paired with a tetra-fed diet cue, regardless of light levels. Similar threat-sensitive inspection patterns were observed towards cichlids paired with a swordtail-fed diet cue only under high light conditions. Our data suggest that chemical cues in the form of prey alarm cues in the diet of the predator, are the primary source of information regarding local predation risk during inspection behaviour, and that visual cues are used when chemical information is unavailable or ambiguous. [source] Complexation of 2,6-Bis(3-pyrazolyl)pyridine,Bis(thiocyanato)iron(II) with a Bridging 4,4,-Bipyridine: A New Example of a Dinuclear Spin Crossover ComplexEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2008Dalila Fedaoui Abstract Investigation of the coordination behavior of 2,6-bis(3-pyrazolyl)pyridine,bis(thiocyanato)iron(II) towards bridging ligands led to the discovery of a novel dinuclear complex showing spin-crossover. Chemical and structural characterization and a first report of physical properties are presented.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Chemical and Electrochemical Behaviours of a New Phenolato-Bridged Complex [(L)MnIIMnII(L)]2+.EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2006Dinuclear Mono-µ-Oxido [(L)MnIII(µ-O)MnIII/IV(L)]2+/3+ Species, Pathways to Mononuclear Chlorido [(L)MnII/III/IVCl]0/1/2+ Abstract The X-ray structure of a new dinuclear phenolato-bridged Mn2II complex abbreviated as [(L)MnMn(L)]2+ (1), where LH is the [N4O] phenol containing ligand N,N -bis(2-pyridylmethyl)- N, -salicylidene-ethane-1,2-diamine ligand, is reported. A J value of ,3.3 cm,1 (H = ,J,1·,2) was determined from the magnetic measurements and the 9.4 GHz EPR spectra of both powder and frozen acetonitrile solution samples were analyzed with temperature. The cyclic voltammetry of 1 displays a reversible anodic wave at E1/2 = 0.46 V vs. SCE associated with the two-electron oxidation of 1 yielding the dinuclear Mn2III complex [(L)MnMn(L)]4+ (2). The easy air oxidation of 1 gives the mono-,-oxido Mn2III complex [(L)Mn(, - O)Mn(L)]2+ (3). A rational route to the formation of the mixed-valence Mn2III,IV complex [(L)Mn(, - O)Mn(L)]3+ (4) starting from 1 by bulk electrolysis at EP = 0.75 V vs. SCE in the presence of one equiv. of base per manganese ion is also briefly reported. Addition of chloride ions to 1 led to the cleavage of the phenolato bridges to give the mononuclear MnII complex [(L)MnCl] (5). Cyclic voltammetry of 5 displays two reversible anodic waves at E1/2 = 0.21 and E1/2 = 1.15 V vs. SCE, assigned to the two successive one-electron abstractions giving the MnIII and MnIV species [(L)MnCl]+ (6) and [(L)MnCl]2+ (7), respectively. The electronic signatures from UV/Visible and EPR spectroscopy of the electrochemically prepared samples of 6 and 7 confirmed the respective oxidation states. For instance, 7 displays a broad and intense absorption band characteristic of a phenolato to MnIV charge-transfer transition at 690 nm (2000 M,1,cm,1) and its 9.4 GHz EPR spectrum shows a strong transition at g = 5.2 consistent with a rhombically distorted S = 3/2 system with a zero-field splitting dominating the Zeeman effect. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Chemical, Mechanical, and Antibacterial Properties of Silver Nanocluster,Silica Composite Coatings Obtained by Sputtering,ADVANCED ENGINEERING MATERIALS, Issue 7 2010Monica Ferraris Abstract Silver nanocluster,silica matrix composite coatings have been deposited by radio frequency (RF) co-sputtering on silica substrates. Field emission scanning electron microscopy and X-ray diffraction spectra of the as deposited and heated samples (150,600,°C) revealed the presence of metal silver nanoclusters, their size depending on the heating treatment. The antibacterial activity of the as deposited and heated samples has been measured in accordance to National Committee for Clinical Laboratory Standards, and it has been demonstrated on samples heated up to 450,°C in contact mode and for samples heated at 600,°C in a liquid environment. Their antibacterial activity was still present after gamma ray and ethylene oxide gas (EtO) sterilization of the samples. Silver leaching tests on the as deposited and heated samples has been measured by graphite furnace atomic absorption spectrometer, revealing an amount ranging from 0.1 to 0.9,µg mm,2, over 28 days. Tape resistance (ASTM D3359-97) and scratch resistance tests have been done on each sample revealing a good adhesion of the coatings on silica. [source] Chlorophyll Catabolites , Chemical and Structural Footprints of a Fascinating Biological Phenomenon,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 1 2009Simone Moser Abstract Twenty years ago, the molecular basis for the seasonal disappearance of chlorophyll was still enigmatic. In the meantime, our knowledge on chlorophyll breakdown has grown considerably. As outlined here, it has been possible to decipher the basic transformations involved in natural chlorophyll breakdown by identification of chlorophyll catabolites in higher plants, and with the help of the synthesis of (putative) catabolic intermediates. In vascular plants, chlorophyll breakdown typically converts the green plant pigments efficiently into colorless and non-fluorescent tetrapyrroles. It involves colored intermediates only fleetingly and in an (elusive) enzyme-bound form. The non-fluorescent chlorophyll catabolites accumulate in the vacuoles of degreened leaves and are considered the products, primarily, of a detoxification process. However, they are effective antioxidants, and may thus also have physiologically beneficial chemical properties.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Sarcodonins and Sarcoviolins, Bioactive Polyhydroxy- p -terphenyl Pyrazinediol Dioxide Conjugates from Fruiting Bodies of the Basidiomycete Sarcodon leucopusEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2004Valeria Calě Abstract Six new polyhydroxy- p -terphenyl pyrazinediol dioxide conjugates (4,9) related to sarcodonin (3) have been isolated from the EtOAc extract of the fruiting bodies of the basidiomycete Sarcodon leucopus and we established their structures by spectral analysis and chemical conversions. Three of them, named sarcodonins , (4), , (5), and , (6), afforded the same peracetate 12 upon acetylation. Compounds 7, 8, and 9 gave peracetate 13 and were characterized as the N -oxide epimers of 3,5, respectively, and are named, accordingly, episarcodonin, episarcodonin ,, and episarcodonin ,. From the EtOH extract, we obtained a mixture of two violet pigments. Chemical and spectroscopic data allowed their structures to be established as the p -terphenyl ortho -quinones related to the sarcodonins, namely sarcoviolin , (10) and episarcoviolin , (11). Compounds 3, 4, 6, and 7 and the mixture of 10 and 11 were found to be active in assays against tumor cell cultures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Influence of Filler Composition on the Microstructure and Mechanical Properties of Steel,Aluminum Joints Produced by Metal Arc Joining,ADVANCED ENGINEERING MATERIALS, Issue 5 2009Leonardo Agudo Jácome Chemical joining of aluminum to steel parts is one of the main challenges in the automotive industry to achieve sound economical solutions for required automobile weight reduction. The cold metal transfer (CMT) is a fusion welding process developed to meet that challenge. It is shown in this paper how the choice of proper filler materials can yield appropriate mechanical performance of specially designed dissimilar CMT butt joints by improving the seam characteristics and weld bead properties. [source] Evolution of Electrical, Chemical, and Structural Properties of Transparent and Conducting Chemically Derived Graphene Thin FilmsADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Cecilia Mattevi Abstract A detailed description of the electronic properties, chemical state, and structure of uniform single and few-layered graphene oxide (GO) thin films at different stages of reduction is reported. The residual oxygen content and structure of GO are monitored and these chemical and structural characteristics are correlated to electronic properties of the thin films at various stages of reduction. It is found that the electrical characteristics of reduced GO do not approach those of intrinsic graphene obtained by mechanical cleaving because the material remains significantly oxidized. The residual oxygen forms sp3 bonds with carbon atoms in the basal plane such that the carbon sp2 bonding fraction in fully reduced GO is ,0.80. The minority sp3 bonds disrupt the transport of carriers delocalized in the sp2 network, limiting the mobility, and conductivity of reduced GO thin films. Extrapolation of electrical conductivity data as a function of oxygen content reveals that complete removal of oxygen should lead to properties that are comparable to graphene. [source] Chemical and isotopic signatures of Na/HCO3/CO2 -rich geofluids, North PortugalGEOFLUIDS (ELECTRONIC), Issue 4 2006J. M. MARQUES Abstract Geochemical and isotopic studies have been undertaken to assess the origin of CO2 -rich waters issuing in the northern part of Portugal. These solutions are hot (76°C) to cold (17°C) Na,HCO3 mineral waters. The ,2H and ,18O signatures of the mineral waters reflect the influence of altitude on meteoric recharge. The lack of an 18O-shift indicates there has been no high temperature water,rock interaction at depth, corroborating the results of several chemical geothermometers (reservoir temperature of about 120°C). The low 14C activity (up to 9.9 pmC) measured in some of the cold CO2 -rich mineral waters (total dissolved inorganic carbon) is incompatible with the presence of 3H (from 1.7 to 4.1 TU) in those waters, which indicates relatively short subsurface circulation times. The ,13C values of CO2 gas and dissolved inorganic carbon range between ,6, and ,1, versus Vienna-Peedee Belemnite, indicating that the total carbon in the recharge waters is being diluted by larger quantities of CO2 (14C-free) introduced from deep-seated (upper mantle) sources, masking the 14C-dating values. The differences in the 87Sr/86Sr ratios of the studied thermal and mineral waters seem to be caused by water,rock interaction with different granitic rocks. Chlorine isotope signatures (,0.4, < ,37Cl < +0.4, versus standard mean ocean chloride) indicate that Cl in these waters could be derived from mixing of a small amount of igneous Cl from leaching of granitic rocks. [source] Release of cell contents and comminution of particles of perennial ryegrass herbage during ingestion by dairy cows fed indoors or grazingGRASS & FORAGE SCIENCE, Issue 3 2006A. Boudon Abstract The effect of feeding indoors fresh perennial ryegrass vs. grazing on ingestive behaviour, release of cell contents and comminution of particles during ingestion, as well as on gas production of ingested boli fermented in vitro, was studied. Indoor feeding and grazing were compared using four dairy cows according to a triple reversal design with six periods. Chemical and morphological composition of the ingested herbage was similar for both indoor feeding and grazing treatments. The intake rate was markedly higher indoors compared with grazing [52·1 vs. 22·9 g dry matter (DM) min,1] with heavier boli and less saliva added per gram of DM intake. The proportions of intracellular nitrogen and chlorophyll released during mastication after ingestion of herbage fed indoors were lower, and the median size of the particles in the boli was larger (5·97 vs. 4·44 mm) compared with grazing. As a result, the rate of gas production in vitro was also lower for herbage fed indoors compared with grazing (0·423 vs. 0·469 mL min,1 g,1 incubated DM). Indoor feeding or grazing may have limited consequences in vivo on the kinetics of availability of nutrients for micro-organisms in the rumen, because the consequences of the more extensive physical damage suffered by herbage ingested at grazing could be compensated by a lower intake rate. [source] Chemical and Isotopic Constraints on the Origin of Wadi El-Tarfa Ground Water, Eastern Desert, EgyptGROUND WATER, Issue 5 2000M. Sultan We evaluated the use of the renewable ground water resources of the Eastern Desert to develop sustainable agriculture in Upper Egypt, an alternative that could alleviate some of Egypt's dependence on water from the Nile River. Ground water from shallow aquifers in the Eastern Desert of Egypt, near the intersection of Wadi El-Tarfa and the Nile River, was analyzed for chemical compositions, stable isotope ratios, and tritium activities. The ground water has a range in total dissolved solids of 300 to 5000 mg/L. Values of ,D and ,18O range from -10 to +34 %o and -2 to +5.2 %o, respectively, and defines a line having a slope of 5.7 that intersects the meteoric water line at about ,D = -15 %o on a plot of 8D versus ,18O. These findings indicate that the water might have been derived by a combination of evaporation of and salt addition to regional precipitation. Only one sample could have been derived directly by evaporation and transpiration of modern Nile River water. Salinization of the ground water could have occurred through dissolution of marine aerosol dry fallout, carbonate minerals, gypsum, and other trace evaporitic minerals at and near the ground surface. Tritium activities ranged from 0.04 to 12.9 TU (tritium unite), indicating that all but one of the samples were derived at least partly from precipitation that occurred within the last 45 years. These data indicate that Nubian Aquifer paleowater is not a significant component of the shallow aquifers of this portion of the Eastern Desert. The most likely source of this ground water is sporadic flash flood events yielding locally voluminous recharge that accumulates in coarse sediments and fractured rock beneath alluvial channels. The magnitude of this renewable ground water resource and its potential for supporting sustainable agriculture require further investigation. [source] Chemical and Bacterial Quality of Aeration-Type Waste Water Treatment System DischargeGROUND WATER MONITORING & REMEDIATION, Issue 2 2007Samuel V Panno On-site waste water treatment systems are a potential source of chemical and bacterial contamination to ground water in areas with highly susceptible aquifers such as the sinkhole plain of southwestern Illinois. Ground water from wells, cave streams, and water that discharges from the numerous springs in this area is typically contaminated with nitrate and enteric bacteria and thus may pose a health hazard to those who come into contact with it. In order to determine if the most popular type of on-site waste water treatment systems in the study area was a potential source, samples of effluents discharged at the land surface from 23 domestic aeration-type on-site waste water treatment systems were collected to characterize their water quality and bacterial contents. Most of the effluents contained relatively large concentrations of sodium (Na+), chloride (Cl,), nutrients (nitrogen [N], phosphate [PO43,], and potassium [K+]), and enteric bacteria. Ion concentration ranges (in mg/L) were Na+ (46 to 416), Cl, (21 to 618), N (4.7 to 67), PO4 -P (1.4 to 48), and K+ (6.0 to 257). The sources of elevated Na+ and Cl, were human waste and NaCl used in the water softening systems of the houses. Ammonium was usually the dominant inorganic N species, indicating incomplete oxidation of the waste water. Discharge of Na+, Cl,, and nutrients could also have negative impacts on ground water and surface water quality, subsurface and surface aquatic ecosystems, and vegetation. Our characterization of effluent from these waste water treatment systems revealed their generally poor quality and the likelihood that they can contaminate ground water in areas with highly vulnerable aquifers. [source] Exploiting Chemical Switching in a Diels,Alder Polymer for Nanoscale Probe Lithography and Data Storage,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2006B. Gotsmann Abstract Reversibly crosslinked polymer films have properties that are beneficial to scanned-probe data storage and lithographic applications that use thermomechanical nanoindentation as a write or expose mechanism. The novel polymer under study contains linkages based on thermally reversible Diels,Alder crosslinking. Thermomechanical properties on the nanometer scale are analyzed by indentation experiments on polymer thin films using heated tips. The underlying indentation mechanism is studied at varying tip temperatures and indentation times, revealing Arrhenius kinetics. This is in contrast to the Williams,Landau,Ferry kinetics usually observed for polymer systems. The discrepancy is explained by the reversible crosslinking incorporated into the structure of the polymer that allows switching between two different states: a rigid, highly crosslinked, low-temperature state, and a deformable, fragmented, high-temperature state. An individual indentation volume of less than 10,20,L (10,000,molecule pairs) is estimated. These kinetics experiments demonstrate that a chemical reaction of only a few thousand molecules can be transduced into a mechanically measurable action. The ability to cycle between two sets of properties in these materials opens up new perspectives in lithography and data storage. Examples of data storage with densities up to 1,Tb,in.,2 and maskless lithography with resolution below 20,nm are demonstrated at writing times of 10,,s per bit/pixel. [source] Selenium-Containing Heterocycles from Isoselenocyanates: Base-Catalyzed Reaction of Malononitrile with Phenyl Isoselenocyanate and Bromoacetonitrile or , -Halogenated KetonesHELVETICA CHIMICA ACTA, Issue 10 2007Geoffroy Abstract The reaction of phenyl isoselenocyanate (1a) with malononitrile (=propanedinitrile) in DMF in the presence of Et3N leads to the intermediate ketene N,Se-hemiacetal 6a, which can be trapped with bromoacetonitrile or , -halogenated ketones 12a and 12b (Scheme,3). The products are [(alkylseleno)(phenylamino)methylene]malononitriles 10 and 13, which are obtained in good yield. In the case of the (2-oxoalkyl)seleno derivatives 13, they are in equilibrium with the cyclic hemiacetals 14. Chemical and spectroscopic evidence for the structures of the new compounds are described. The structure of 14a was established by X-ray crystallography. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||