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High Water Content (high + water_content)
Selected AbstractsResponses of shoot growth and survival to water stress gradient in diploid and tetraploid populations of Lolium multiflorum and L. perenneGRASSLAND SCIENCE, Issue 4 2006Shu-ichi Sugiyama Abstract Drought stress is one of the critical environmental factors in determining growth and survival of herbage grasses. In this study, by using a hydroponic culture system including different amounts of polyethylene glycol (PEG), responses of plant shoots to water stress in four different intensities (0 Mpa, ,0.6 Mpa, ,1.2 Mpa and ,1.8 Mpa) were examined in diploid and tetraploid cultivars of Italian ryegrass (Lolium multiflorum) and perennial ryegrass (L. perenne). Since freezing injury is caused by cell dehydration, freezing tolerance was also examined for six subzero temperatures (,11, ,12, ,14, ,16, ,18 and ,20°C) in both species. L. multiflorum had a larger shoot biomass at all stress intensities and a lower survival rate under severe water stress and freezing stress conditions than L. perenne. Thus, there was a trade-off (negative correlation) between potential growth under a stress-free condition and survival under a severe stress condition in diploid and tetraploid cultivars of both species. This trade-off was mediated by tissue water content. High water content led to a high growth rate through increasing specific leaf area, while low water content resulted in a high tissue osmotic potential that could confer high cell dehydration tolerance. [source] The preparation and characterization of fiber reinforced alginate hydrogelJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Yimin Qin Abstract To prepare fiber reinforced alginate hydrogels, calcium alginate fibers were mixed with aqueous sodium alginate solutions. Tests were carried out to assess the amount of calcium ions released from two types of alginate fibers, i.e., those made from alginate rich in guluronic acid (high G) and in mannuronic acid (high M), respectively. Experimental results showed that more calcium ions were released from the high M fibers and the hydrogel made from the high M fibers had a higher viscosity than that made from high G fibers. The water absorption and donating properties of these hydrogels were assessed by placing them in contact with gelatine gels. The results showed that alginate hydrogels with a high alginate content are capable of absorbing water from gelatine gels, while those with a high water content are able to donate water. When silver containing particles were mixed into the alginate solution, it was also possible to prepare fiber reinforced alginate hydrogel with antimicrobial properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Enhancing high water content biomass gasification with impregnated Ca in fuel dryingAICHE JOURNAL, Issue 10 2006Guangwen Xu Abstract In view of energy conversion efficiency, the gas production from high water content (>60 wt.%) biomass via gasification is necessarily conducted with fuel drying in advance. In regard to this kind of processes, the present study was devised to impregnate Ca onto fuel during fuel drying and thereby to increase fuel's gasification reactivity to raise the gas production efficiency with minimal additional cost. By employing wet coffee grounds as a model biomass fuel and slurry dewatering in kerosene as the adopted drying technology, the Ca impregnation was implemented through dosing Ca(OH)2 into a fuel-kerosene slurry and in turn treating the slurry in the same way as for the case without Ca addition. The resulting Ca (4.0 wt.% load in CaO base) exhibited high dispersion through the fuel matrix in both SEM-EDX image and XRD spectrum. Gasification of the fuel in a pilot dual fluidized gasification setup further demonstrated that the fuel possessed distinctively high reaction reactivity. This led it to show C and H conversions of 91% and 138%, respectively, at a reaction temperature of about 1083 K, whereas these conversions were only 70% and 92% for the fuel with a similar amount of physically mixed CaO. The catalytic effect of the impregnated Ca manifested also on hydrocarbon reforming and water gas shift, making the resulting product gas evidently rich in H2 and lean in CO and hydrocarbons. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source] Isergonic relationship in the acid-catalyzed hydrolysis of carboxylic esters with hydrogen-bonding capability,JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 6-7 2004Julio F. Mata-Segreda Abstract The average value of the enthalpies of activation for the acid-catalyzed hydrolyses of ethyl 2-hydroxypropanoate and five acetate esters with hydrogen bonding capability is 57±7,kJ,mol,1 (p,=,0.05). This value is 11,kJ,mol,1 lower than the mean observed for primary and secondary alkyl acetates and ethyl alkanoates, measured in water and in mixtures of water with organic solvent with high water content. The difference is attributed to tighter transition-state complex hydration via hydrogen bonding, relative to reactant ester species. Enthalpy,entropy compensation with an isokinetic temperature of 346,K was found to be valid at p<0.05, a value typical for solvent-mediated kinetic effects. Copyright © 2004 John Wiley & Sons, Ltd. [source] Nutrient content of some mushroom species of the genus Termitomyces consumed in CameroonMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 3 2003Germain Kansci Abstract The nutrient content (water, lipids, proteins, ashes, crude fibres) of six mushroom species (Termitomyces le Testui, T. aurantiacus, T. schimperi, T. mammformis, T. mboudaeïna Mossebo sp. nov., and T. subclypeatus forme bisporus sp. nov.) of the genus Termitomyces from Cameroon was determined. These mushrooms have a high water content (83.3,94.3 g/100 g wet matter) and contain more lipids than species from temperate countries (2.5,5.4 g/100 g dry weight( with high proportions of polyunsaturated fatty acids (45.1,65.1% of total fatty acid methyl esters) and remarkable proportions of crude fibres (17.5,24.7 g/100 g dry weight). Their protein content varied between 15.1 and 19.1 g/100 g dry weight and ash content between 5.2 and 14.4. The species T. mammiformis was found particularly rich in minerals with 14.4 g ash/100 g dry material, that is up to 2.4 g/100 g fresh weight. [source] Collagen dynamics in articular cartilage under osmotic pressureNMR IN BIOMEDICINE, Issue 8 2006Göran Zernia Abstract Cartilage is a complex biological tissue consisting of collagen, proteoglycans and water. The structure and molecular mobility of the collagen component of cartilage were studied by 13C solid-state NMR spectroscopy as a function of hydration. The hydration level of cartilage was adjusted between fully hydrated (,80 wt% H2O) and highly dehydrated (,30 wt% H2O) using the osmotic stress technique. Thus, the conditions of mechanical load could be simulated and the response of the tissue macromolecules to mechanical stress is reported. From the NMR measurements, the following results were obtained. (i) Measurements of motionally averaged dipolar 1H,13C couplings were carried out to study the segmental mobility in cartilage collagen at full hydration. Backbone segments undergo fast motions with amplitudes of ,35° whereas the collagen side-chains are somewhat more mobile with amplitudes between 40 and 50°. In spite of the high water content of cartilage, collagen remains essentially rigid. (ii) No chemical shift changes were observed in 13C cross-polarization magic angle spinning spectra of cartilage tissue at varying hydration indicating that the collagen structure was not altered by application of high osmotic stress. (iii) The 1H,13C dipolar coupling values detected for collagen signals respond to dehydration. The dipolar coupling values gradually increase upon cartilage dehydration, reaching rigid limit values at ,30 wt% H2O. This indicates that collagen is essentially dehydrated in cartilage tissue under very high mechanical load, which provides insights into the elastic properties of cartilage collagen, although the mechanical pressures applied here exceed the physiological limit. Copyright © 2006 John Wiley & Sons, Ltd. [source] Structure of cyclized green fluorescent proteinACTA CRYSTALLOGRAPHICA SECTION D, Issue 9 2002Andreas Hofmann Crystals of cyclic green fluorescent protein (cGFP) engineered by the previously reported split intein technology [Iwai et al. (2001), J. Biol. Chem.276, 16548,16554] were obtained and the structure was solved using molecular replacement. Although the core of the protein can unambiguously be fitted from the first to the last residue of the genuine sequence, the electron density in the region of the linker peptide is rather poor owing to the high water content of the crystals. Therefore, it is concluded that this part of the protein is highly disordered in the present structure and is very flexible. This is supported by the absence of crystal contacts in the linker-peptide region and the fact that the core of the protein exhibits a very similar conformation to that known from other GFP structures, thereby not implicating any constraints arising from the presence of the artificial linker. Nevertheless, the density is consistent with the loop being intact, as confirmed by mass spectroscopy of dissolved crystals. The present structure contains an antiparallel cGFP dimer where the dimer interface is clearly different from other crystal structures featuring two GFP molecules. This adds further support to the fact that the cylinder surface of GFP is rather versatile and can employ various polar and non-polar patches in protein,protein interactions. [source] The lawsonite paradox: a comparison of field evidence and mineral equilibria modellingJOURNAL OF METAMORPHIC GEOLOGY, Issue 8 2006G. L. CLARKE Abstract Lawsonite equilibria are predicted to occur over a broad P,T spectrum developed during subduction, yet lawsonite-bearing assemblages are rare. In the context of mafic mineral equilibria modelled for the range of common crustal metamorphism (4,23 kbar, 400,750 °C) using the system Na2O-CaO-K2O-FeO-MgO-Al2O3 -SiO2 -H2O and the software thermocalc, unusually high water contents are demanded by lawsonite assemblages. As a consequence, lawsonite assemblages are predicted to have difficulty forming and lawsonite equilibria to be uncommon. Metabasalt undergoing cooler subduction may experience substantial periods involving the metastable persistence of mineral assemblages because of water under-saturation with non-occurrence of recrystallization. If formed, lawsonite-bearing assemblages are observed to be highly unstable; their preservation requires that exhumation be accompanied by substantial cooling. The amount of structurally bound H2O in minerals plays a critical role in the formation and preservation of mineral assemblages, controlling key changes in rocks undergoing subduction. [source] Structural motifs in the maturation process of peptide hormones.JOURNAL OF PEPTIDE SCIENCE, Issue 2 2002The somatostatin precursor. Abstract Synthetic peptides reproducing both the native domain around the dibasic cleavage site of pro-somatostatin, and mutated sequences thereof, previously assayed in site-directed mutagenesis experiments, have been studied by CD in different solvent systems, such as water, TFE/H2O, MeCN/H2O and aqueous SDS, in order to ascertain the ability of each solvent to stabilize secondary structural motifs. A combination of deconvolution methods and empirical calculations, that allow subtraction of the contributions due to unordered structures from the spectra, suggests that mainly two distinct families of ordered conformers containing ,-helix and/or structurally different ,-turns are present in solution, the relative stability of the different conformers depending on the nature of the solvent. The presence of ,-turns is in line with a previous NMR study in DMSO and DMSO/H2O. Comparison of the CD spectra in aqueous SDS of peptides undergoing processing with a sequence not processed in vivo shows that only the latter possesses a stable and detectable ,-helix population. This observation suggests that the structuration involving ,-turns but no ,-helix, which was observed by CD both in SDS and organic solvent/H2O mixtures at high water contents, might be of biological significance. The similarity of this structuration to molecular models obtained from NMR data in DMSO and DMSO/H2O is discussed. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd. [source] Beschichtungen auf direkt befahrenen Tiefgaragenbodenflächen von Weißen Wannen.BETON- UND STAHLBETONBAU, Issue 7 2006Physikalische Beanspruchungen, Planungsgrundlagen, alternative Beschichtungsvarianten Nach DIN 1045-1 müssen direkt befahrene Parkdecks mit zusätzlichen Maßnahmen ausgeführt werden, zu denen man unter anderem rißüberbrückende Beschichtungen mindestens der Klasse OS 11 nach Instandsetzungsrichtlinie des DAfStb zählt. Die auf dem Markt verfügbaren rißüberbrückenden Beschichtungssysteme mit Allgemeinem bauaufsichtlichem Prüfzeugnis sind für die Beschichtung von Betonoberflächen mit extremen Wassergehalten (Wassersättigungsgrade bis 90 %), wie sie häufig in Bodenplatten Weißer Wannen vorkommen, nicht geeignet. Schadensfälle aus der Baupraxis zeigen, daß gelegentlich an eignungsgeprüften OS-11-Systemen osmotisch induzierte Blasenerscheinungen, vorzugsweise bei rückseitig durchfeuchteten Bodenplatten wasserundurchlässiger Tiefgaragengeschosse, auftreten. Daher werden die physikalischen Beanspruchungen der Beschichtung (osmotische Transportvorgänge, Kapillardrücke, hydrostatische Drücke und Gasdrücke) quantitativ abgeschätzt und dem Leistungsvermögen (Beanspruchbarkeit) der marktüblichen Systeme gegenübergestellt sowie alternative Beschichtungsvarianten vorgestellt. Ferner werden baupraktische Empfehlungen zur Vermeidung von Beschichtungsschäden erläutert. Coatings on directly vehicle-carrying floor slabs of watertight concrete constructions in underground carparks physical stresses , design codes , alternative coating systems According to DIN 1045-1 directly vehicle-carrying park decks have to be realized with additional measures (crack-bridging coating systems). At least surface protection system 11 (SPS 11) according to the Guidelines for the Protection and Repair of Concrete Components of the German Committee on Reinforced Concrete (DAfStb) are among others a possibility to meet this requirement. On the market available crack-bridging coating systems with a general technical approval are not usefull on concrete surfaces with high water contents (water saturation values of 90 %) as they may occur in floor slabs of watertight concrete constructions. Experiences with practical damage cases show, that with approved SPS 11-systems osmotic induced bubbles may occur preferably on backside saturated floor slabs of watertight concrete constructions. In consequence the physical stresses of a coating (osmotic processes, capillarity reactions, hydraulic pressures as well as gas pressures) will be quantitatively estimated and compared with the capability of market systems. Alternative coating systems are presented and practical recommendations in order to avoid damages are given. [source] | |||||||||||||