bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of dehydration rate on the vitrification of corn protein
Authors: Sabino Marcos A. , Pauchard Ludovic , Allain Catherine , Mangavel Cécile , Zeng Ming , Lourdin Denis 
Published: June 2008

AbstractThis article deals with the physicochemical mechanisms involved during the desiccation of cereals, to understand the basis of their endosperm structure: vitreous endosperm is compact and floury endosperm is porous, giving the endosperm its hard and soft textures, respectively. Dehydration of zein (the most abundant protein in the vitreous region of the corn endosperm) was investigated for water contents ranging from ∼ 50% to 10% (wet basis). A system of partial confinement of zein pills was optimized to compare both slow and rapid dehydration on two separate domains of the same sample. Macroscopic observations, porosity analysis, and scanning electron microscopy showed that either a compact or porous structure is obtained, depending on the dehydration rate. The glass transition temperature (Tg) of zein, which varies from 160°C for dry zein to about 15°C for zein with 25% water content, is mainly dependent on water content. A state diagram of the zein/water system, including ice melting, was determined from calorimetric measurements of state and phase temperature changes. The different porous and compact structures observed on vitreous zein are discussed in terms of collapse and dehydration rate. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Use of modified poly(ϵ‐caprolactone) in the compatibilization of poly(ϵ‐caprolactone)/maize starch blends
Authors: Pascente C. , Márquez L. , Balsamo V. , Müller A. J. 
Published: June 2008

AbstractIn this work, the compatibilization of a poly(ϵ‐caprolactone) with a number‐average molecular weight of 120,000 g/mol (PCL120) and maize starch was investigated by the addition of a chemically modified poly(ϵ‐caprolactone). Two types of blends were prepared by melt extrusion. In type A blends, low‐molecular‐weight compatibilizers were used: (1) a poly(ϵ‐caprolactone) with a number‐average molecular weight of 10,000 g/mol that was reacted with maleic anhydride to obtain chains terminating in carboxylic groups and (2) low‐molecular‐weight poly(ϵ‐caprolactone)s (number‐average molecular weights of 600 and 2000 g/mol) with one pendant carboxylic group within the chains. With these groups of blends, tensile testing and scanning electron microscopy demonstrated that the compatibilizers were generally effective in inducing a better dispersion for a 60/40 poly(ϵ‐caprolactone)/maize starch blend with a compatibilizer, improving the mechanical properties in comparison with uncompatibilized blends. The blends with 30% starch were not improved by the addition of compatibilizer, and this may be related to the rheology of the blends during preparation. In type B blends, high‐molecular‐weight compatibilizers were prepared through the grafting of variable amounts of acrylic acid or maleic anhydride to PCL120 chains. The best compatibilizer action was obtained with 0.7 wt % maleic anhydride grafted to PCL120 because both the dispersion and mechanical properties were further improved in comparison with uncompatibilized blends and type A blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Morphology and photophysical properties of a thermally responsive fluorescent material based on a rod‐coil tri‐block copolymer
Authors: Ma Zhun , Qiang Liangliang , Zheng Zhe , Wang Yanyan , Zhang Zhijian , Huang Wei 
Published: June 2008

AbstractA thermally responsive rod‐coil poly[poly (N‐isopropylacrylamide)‐b‐polyfluorene‐b‐poly(N‐isopropylacrylamide)] triblock copolymer has been successfully synthesized by atom transfer radical polymerization from an end‐functionalized macroinitiator. The thermochromic behavior and relevant morphology of this polymer were investigated by UV‐vis spectra, DLS, and AFM, respectively, at various temperatures. A thermally responsive fluorescent material was achieved facilely by combining the optically active polyfluorene with temperature‐responsive poly(N‐isopropylacrylamide). All the measurements demonstrated that in the region of 25–45°C, the polymer underwent a phase transition and the corresponding change in optical properties in its water solution. However, the polymer did not show completely reversible behavior upon heating and cooling. On the basis of the comparison with two other thermally responsive conjugated polymers in literatures, a tentative mechanism has been proposed that π–π interaction induced rigid segments to remain chain conformation and packing styles as in collapsed state. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal stability of surfactants with amino and imido groups in poly(ethylene terephthalate)/clay composites
Authors: Yuan Xuepei , Li Chuncheng , Guan Guohu , Xiao Yaonan , Zhang Dong 
Published: June 2008

AbstractEffects of thermal stability of surfactants with amino and imido groups on thermal properties of poly(ethylene terephthalate) (PET)/clay composites were studied. The imidosilane surfactant was synthesized successfully from the imide reaction between amino silane and phthalic anhydride. TGA shows that imidosilane decomposition behaviors have two major stages according to the degradations of different functional groups. After melt extrusion, the decomposition of amino functional groups in amino surfactants decreases the thermal stability of organoclay and accelerates the degradation behaviors of PET composites. Because of the enhanced thermal stability of imidosilane surfactants, PET/imido‐palygorskite (PT) composites represent enhanced thermal stability, good dispersion and low thermal expansion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Visualization and quantification of the mechanical deformation induced by an electrical field in poly(ethylene naphthalene 2,6‐dicarboxylate) (PEN) films
Authors: Zegnini Boubakeur , Lahoud Nadine , Boudou Laurent , Martinez‐Vega Juan 
Published: June 2008

AbstractAn optical nondestructive strain measurement technique was performed to analyze the mechanical deformation induced by an electrical field within the insulating materials. Poly(ethylene naphthalene 2,6‐dicarboxylate) (PEN) films were then subjected to constant electrical fields right up to their electrical breakdown. The experimental technique made it possible to follow the various stages of the mechanical behavior of PEN in real time. The final breakdown occurred in the observation zone and the related mechanical deformation was captured. A “margarita” structure was observed with a hole at the center. The experimental results indicated that the level of the induced‐mechanical deformations depended on the local environment. We defined two different zones representing the inside and the outside of the damaged area. The induced‐deformations were larger in the damaged zone. It was also observed that deformations increased when the sample had a lower degree of crystallinity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Surface modification of medical poly(vinyl chloride) with O− water
Authors: Zhao E , Wang Lian , Yan Lifeng , Torimoto Yoshifumi , Li Quanxin 
Published: June 2008

AbstractA novel approach to the surface modification of medical poly(vinyl chloride) (PVC) with atomic oxygen radical anions‐dissolved solution (named as O– water) has been investigated. The O– water was generated by bubbling of the O– (atomic oxygen radical anion) flux into the deionized water. The surface hydrophilicities of the PVC films were investigated by contact angle measurements before and after the O– water treatment. Surface chemical compositions of the original and treated PVC films were studied using X‐ray photoelectron spectroscopy (XPS). The influence of the O– water on the surface roughness as well as morphological alterations of the PVC films was investigated by atomic force microscopy (AFM) measurements. Results show that the O– water treatment caused an obvious increase in the surface hydrophilicity and surface energy and also caused an alteration of the surface chemical composition, with an increase in surface roughness because of the etching effect. The modifications are attributed to the formation of oxygen‐containing functional groups (CO, CO, OCO, etc.) and dechlorination, mainly caused by the reactions between the molecules on PVC surfaces and the active oxygen species in the O– water. Present method, potentially, may be applied to the surface modification of polymers and other heat‐sensitive materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Hydroxyalkylation of oxamic acid with propylene carbonate: Synthesis, composition, and properties of products
Authors: Zarzyka‐Niemiec Iwona 
Published: June 2008

AbstractThe work aimed at synthesis of hydroxypropoxy compounds containing oxalamidoester group from oxamic acid (OA) and propylene carbonate (PC) substrates. The thermal stability of obtained products was tested to estimate their usefulness for formation of polyurethane foams. The influence of initial molar ratio of reagents, amount of catalyst and temperature of reaction between OA and PC on structure of product was studied. The Matrix‐Assisted Laser Desorption Ionization Time of Flight (MALDI ToF) analysis of products evidenced that in the conditions used the formation of hydroxypropoxy derivatives of OA was accompanied by homocondensation of OA, which became minor process in presence of excess of PC. The physicochemical and thermal properties of products were studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Comparison of sympatric freshwater turtle populations from an urbanized Sydney catchment
Authors: Burgin Shelley , Ryan Michelle 
Published: June 2008

Abstract

Australian freshwater turtles are widely distributed throughout the continent, and in each river catchment there are at least two taxa. In south‐eastern Australia Chelodina longicollis and forms of Emydura macquarii co‐habit within a waterway, although they have been shown to partition habitat within the water column in non‐urban bodies of water. Limited comparative data are available for the urban populations.
Within urban Sydney C. longicollis (eastern long‐necked turtle) and Emydura macquarii dharuk (Sydney short‐necked turtle) share habitat. However, in contrast with non‐urban studies of C. longicollis and other sympatric E. macquarii taxa, it was observed that the population profile of the two species was similar at all sites, and that C. longicollis were present in greater numbers than E. m. dharuk.
The continued degradation of preferred habitat, low recruitment, and potential competition from introduced turtles place both species in a precarious position.
The shallow, impounded waterways of the regulated urban bodies of water align more closely with the preferred habitat of C. longicollis than with that of forms of E. macquarii, which prefer deeper flowing waters or large wetlands adjacent to rivers. Emydura m. dharuk may be at greatest risk of extinction in urban areas.
Across urban Sydney, the low numbers of E. m. dharuk compared with C. longicollis may be due to the lack of mobility of E. m. dharuk such that individuals tend to be stranded in sub‐optimal habitat. In contrast, C. longicollis has a greater propensity for overland movement, and a preference for the ‘new habitat’ resulting from urban impacts on the associated waterways, and thus appears to be able to utilize these modified urban waters more successfully.
Copyright © 2008 John Wiley & Sons, Ltd.
A proposal for a dynamic h‐type index
Authors: Rousseau Ronald , Ye Fred Y. 
Published: June 2008

AbstractA time‐dependent h‐type indicator is proposed. This indicator depends on the size of the h‐core, the number of citations received, and recent change in the value of the h‐index. As such, it tries to combine in a dynamic way older information about the source (e.g., a scientist or research institute that is evaluated) with recent information.
Amiodarone modulates pharmacokinetics of low‐dose methotrexate in rats
Authors: Fuksa Leos , Brcakova Eva , Cermanova Jolana , Hroch Milos , Chladek Jaroslav , Kolouchova Gabriela , Malakova Jana , Martinkova Jirina , Staud Frantisek , Micuda Stanislav 
Published: June 2008

AbstractClinical studies of low‐dose methotrexate (LDMTX) pharmacokinetics document increased plasma concentrations of MTX after co‐administration of the drug with amiodarone or macrolide antibiotics. As drug–drug interactions may increase the toxicity of LDMTX, a rat model was used to follow renal and biliary elimination of MTX during its constant‐rate i.v. infusion and concomitant single bolus i.v. injections of amiodarone or azithromycin. The mean steady‐state plasma concentration of 1.7±0.1 µmol/l was reached and the total clearance achieved 17.7±1.0 ml/min/kg. Administration of amiodarone decreased the biliary clearance of MTX to 73% of the control values (p<0.05). Correspondingly, the total clearance decreased to 72% and plasma MTX concentrations were augmented to 2.5±0.4 µmol/l (p<0.05). Amiodarone‐treated rats exhibited a 3.3‐fold decrease in the renal clearance (p<0.05) of conjugated bilirubin, which was associated with its increased plasma concentration. In contrast, azithromycin did not alter any of the MTX pharmacokinetic parameters. In conclusion, this is the first report describing the impairment of MTX hepatic elimination during co‐administration with amiodarone. This study also provides new insight into acute amiodarone‐induced hyperbilirubinaemia, where increased bilirubin production and decreased renal clearance may contribute to this effect. Importantly, azithromycin seems to be a safe co‐medication during LDMTX therapy. Copyright © 2008 John Wiley & Sons, Ltd.
Modeling Neisseria meningitidis B metabolism at different specific growth rates
Authors: Baart Gino J.E. , Willemsen Marieke , Khatami Elnaz , de Haan Alex , Zomer Bert , Beuvery E. Coen , Tramper Johannes , Martens Dirk E. 
Published: June 2008

AbstractNeisseria meningitidis is a human pathogen that can infect diverse sites within the human host. The major diseases caused by N. meningitidis are responsible for death and disability, especially in young infants. At the Netherlands Vaccine Institute (NVI) a vaccine against serogroup B organisms is currently being developed. This study describes the influence of the growth rate of N. meningitidis on its macro‐molecular composition and its metabolic activity and was determined in chemostat cultures. In the applied range of growth rates, no significant changes in RNA content and protein content with growth rate were observed in N. meningitidis. The DNA content in N. meningitidis was somewhat higher at the highest applied growth rate. The phospholipid and lipopolysaccharide content in N. meningitidis changed with growth rate but no specific trends were observed. The cellular fatty acid composition and the amino acid composition did not change significantly with growth rate. Additionally, it was found that the PorA content in outer membrane vesicles was significantly lower at the highest growth rate. The metabolic fluxes at various growth rates were calculated using flux balance analysis. Errors in fluxes were calculated using Monte Carlo Simulation and the reliability of the calculated flux distribution could be indicated, which has not been reported for this type of analysis. The yield of biomass on substrate (Yx/s) and the maintenance coefficient (ms) were determined as 0.44 (±0.04) g g−1 and 0.04 (±0.02) g g−1 h−1, respectively. The growth associated energy requirement (Yx/ATP) and the non‐growth associated ATP requirement for maintenance (mATP) were estimated as 0.13 (±0.04) mol mol−1 and 0.43 (±0.14) mol mol−1 h−1, respectively. It was found that the split ratio between the Entner‐Doudoroff and the pentose phosphate pathway, the sole glucose utilizing pathways in N. meningitidis, had a minor effect on ATP formation rate but a major effect on the fluxes going through for instance the citric‐acid cycle. For this reason, we presented flux ranges for underdetermined parts of metabolic network rather than presenting single flux values, which is more commonly done in literature. Biotechnol. Bioeng. 2008;101: 1022–1035. © 2008 Wiley Periodicals, Inc.
Effect of oxygen gradients on the activity and microbial community structure of a nitrifying, membrane‐aerated biofilm
Authors: Downing Leon S. , Nerenberg Robert 
Published: June 2008

AbstractShortcut nitrogen removal, that is, removal via formation and reduction of nitrite rather than nitrate, has been observed in membrane‐aerated biofilms (MABs), but the extent, the controlling factors, and the kinetics of nitrite formation in MABs are poorly understood. We used a special MAB reactor to systematically study the effects of the dissolved oxygen (DO) concentration at the membrane surface, which is the biofilm base, on nitrification rates, extent of shortcut nitrification, and microbial community structure. The focus was on anoxic bulk liquids, which is typical in MAB used for total nitrogen (TN) removal, although aerobic bulk liquids were also studied. Nitrifying MABs were grown on a hollow‐fiber membrane exposed to 3 mg N/L ammonium. The MAB intra‐membrane air pressure was varied to achieve different DO concentrations at the biofilm base, and the bulk liquid was anoxic or with 2 g m−3 DO. With 2.2 and 3.5 g m−3 DO at the biofilm base, and with an anoxic bulk‐liquid, the ammonium fluxes were 0.75 and 1.0 g N m−2 day−1, respectively, and nitrite was the main oxidized nitrogen product. However, with membrane DO of 5.5 g m−3, and either zero or 2 g m−3 DO in the bulk, the ammonium flux was around 1.3 g N m−2 day−1, and nitrate flux increased significantly. For all experiments, the cell density of ammonium oxidizing bacteria (AOB) was relatively uniform throughout the biofilm, but the density of nitrite oxidizing bacteria (NOB) decreased with decreasing biofilm DO. Among NOB, Nitrobacter spp. were dominant in biofilm regions with 2 g m−3 DO or greater, while Nitrospira spp. were dominant in regions with less than 2 g m−3 DO. A biofilm model, including AOB, Nitrobacter spp., and Nitrospira spp., was developed and calibrated with the experimental results. The model predicted the greatest extent of nitrite formation (95%) and the lowest ammonium oxidation flux (0.91 g N m−2 day−1) when the membrane DO was 2 g m−3 and the bulk liquid was anoxic. Conversely, the model predicted the lowest extent of nitrite formation (40%) and the highest ammonium oxidation flux (1.5 g N m−2 day−1) when the membrane‐DO and bulk‐DO were 8 g m−3 and 2 g m−3, respectively. The estimated kinetic parameters for Nitrospira spp., revealed a high affinity for nitrite and oxygen. This explains the dominance of Nitrospira spp. over Nitrobacter spp. in regions with low nitrite and oxygen concentrations. Our results suggest that shortcut nitrification can effectively be controlled by manipulating the DO at the membrane surface. A tradeoff is made between increased nitrite accumulation at lower DO, and higher nitrification rates at higher DO. Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc.
Multivariate modeling and exploration of environmental n‐way data from bulk precipitation quality control
Authors: Astel Aleksander , Małek Stanisław 
Published: June 2008

AbstractThis paper describes the results of study on modeling and exploration of a three‐way environmental data set acquired from monitoring bulk precipitation chemistry collected in the Dupniański Stream Catchment (Silesian Beskid, Southern Poland) using Tucker3 modeling and self‐organizing map approach. It appears that the constructed Tucker3 model is appropriate for the studied data and explains more than 91% of the data variance. The Tucker3 model allows to distinguish ‘heavy metals‐dust particles’ and ‘anthropogenic’ factors responsible for chemical profiles of bulk precipitation and to identify seasonal variations in bulk precipitation quality. A self‐organizing map approach confirms Tucker3 modeling results and additionally allows to identify a strong, temporary impact of remote pollution sources located in the vicinity of Polish‐Czech Republic border and indicates a cyclical impact of remote pollution sources located in highly industrialized Katowice and Bełchatów regions. Copyright © 2008 John Wiley & Sons, Ltd.
MR imaging assessment of the kinetics of P846, a new gadolinium‐based MR contrast medium, in ischemically injured myocardium
Authors: Jacquier Alexis , Wendland Michael , Do Loi , Robert Philippe , Corot Claire , Higgins Charles B. , Saeed Maythem 
Published: June 2008

AbstractThe objectives of the study were: (1) to compare the kinetics of a new gadolinium‐based low‐diffusibility magnetic resonance (MR) contrast medium, P846 and Gd‐DOTA in left ventricular (LV) blood and in normal and ischemically injured myocardium using inversion recovery echo‐planar imaging (IR‐EPI) and (2) to compare the enhancement pattern after injection of P846 with Gd‐DOTA, using T1‐weighted spin‐echo imaging (T1‐SE). Sixteen rats were subjected to left descending artery (LAD) occlusion for 30 min, followed by 2.5 h reperfusion. MR imaging was performed before and after administration of the contrast medium in two different groups of animals: one group (n = 8) received 0.05 mmol kg−1 P846 and the other (n = 8) 0.1 mmol kg−1 Gd‐DOTA. A blipped IR‐EPI and a multislice T1‐SE were performed before injection and for 90 min after injection. T1‐values were derived by fitting regional signal intensity on the IR‐EPI images, the R1, ΔR1 (R1postcontrast – R1precontrast) and ΔR1 ratios were calculated in LV blood, normal and injured myocardium. On SE‐T1, the signal intensity ratio (SI) and extent of injury were measured. True infarct size was measured using histochemical staining. Changes in ΔR1 were 4.8 times greater with 0.05 mmol kg−1 P846 than with 0.1 mmol kg−1 Gd‐DOTA in LV blood (6.3 ± 0.9 vs 0.9 ± 0.1 s−1, p < 0.0001), normal (1.7 ± 0.2 vs 0.34 ± 0.03 s−1, p < 0.0001) and ischemically injured myocardium (5.4 ± 0.4 vs 1.6 ± 0.1 s−1, p < 0.0001). MR imaging experiments showed that the signal enhancement with P846 is longer (90 min), which might be explained by a lower diffusion of P846 compared with Gd‐DOTA (30 min). P846 differentiates viable and nonviable myocardium. Despite lower gadolinium dose, P846 permits differentiation of viable and nonviable myocardium owing to a high contrast and a long imaging window with conventional t1‐weighted SE sequence. Copyright © 2008 John Wiley & Sons, Ltd.
Multi‐Hamiltonian structure for the finite defocusing Ablowitz‐Ladik equation
Authors: Gekhtman Michael , Nenciu Irina 
Published: June 2008

AbstractWe study the Poisson structure associated to the defocusing Ablowitz‐Ladik equation from a functional‐analytical point of view by reexpressing the Poisson bracket in terms of the associated Carathéodory function. Using this expression, we are able to introduce a family of compatible Poisson brackets that form a multi‐Hamiltonian structure for the Ablowitz‐Ladik equation. Furthermore, we show using some of these new Poisson brackets that the Geronimus relations between orthogonal polynomials on the unit circle and those on the interval define an algebraic and symplectic mapping between the Ablowitz‐Ladik and Toda hierarchies. © 2008 Wiley Periodicals, Inc.