bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of heat and oxidative damage during storage of processed tomato products. II. Study of oxidative damage indices
Authors: Lavelli Vera , Giovanelli Gabriella 
Published: July 2003

AbstractTomato products (pulp, puree and paste) submitted to accelerated aging (30, 40 and 50 °C for 3 months) were studied to evaluate variations in the kinetics of the degradation of antioxidants and antioxidant activity. The carotenoids lycopene and β‐carotene, ascorbic acid, rutin and total phenolics were analysed. The antioxidant activity was measured using (a) the xanthine oxidase (XOD)/xanthine system, which generates superoxide radicals and hydrogen peroxide, and (b) the linoleic acid/CuSO4 system, which promotes lipid peroxidation. The ascorbic acid content decreased even at 30 °C, following pseudo‐first‐order kinetics, with an activation energy of 105 200 J mol−1 for tomato pulp and 23 600 J mol−1 for tomato paste. The lower the initial ascorbic acid content, the higher was the degradation rate. Variations in phenolic compounds occurred at 40 °C and higher, following pseudo‐zero order kinetics. The antioxidant activity of the hydrophilic fraction of the tomato products depended on both antioxidant degradation and the Maillard reaction and could not be described by a kinetic model. The β‐carotene content decreased even at 30 °C, whereas the lycopene content was stable in all samples. The antioxidant activity of the lipophilic fraction of the tomato products decreased following pseudo‐first order kinetics, with an activation energy of 22 200 J mol−1 for tomato pulp and 20 200 J mol−1 for tomato paste. It is concluded that significant ‘oxidative damage’ can occur in tomato products during their commercial shelf‐life. Copyright © 2003 Society of Chemical Industry
Simplified process for the production of sesame protein concentrate. Differential scanning calorimetry and nutritional, physicochemical and functional properties
Authors: Escamilla‐Silva Eleazar M , Guzmán‐Maldonado Salvador H , Cano‐Medinal Alicia , González‐Alatorre Guillermo 
Published: July 2003

AbstractThe effects of a simplified production process on the yield, protein content and differential scanning calorimetric analysis of a sesame protein concentrate were studied. The results were compared with those for similar products obtained by the traditional method. The protein content of the (spray‐dried) sesame concentrate obtained by the simplified process (549 g kg−1) was similar to that of the concentrates obtained by the traditional method (515–565 g kg−1). Spray‐dried samples showed higher Td and Tm and lower ΔH than freeze‐dried samples. In addition, the chemical composition, nutritional quality and physicochemical and functional characteristics of the sesame protein concentrate obtained by the simplified process were compared with those of a similar soybean product. The protein, lysine and calcium contents of the sesame concentrate were lower than those of the soybean concentrate, but the digestibility of the protein was the same for both products. The phytic acid content of the sesame concentrate diminished significantly, but was still higher than that of the soybean concentrate. The water absorption and protein solubility were higher for the soybean concentrate, whereas the oil absorption and viscosity at pH 3 were higher for the sesame concentrate. Copyright © 2003 Society of Chemical Industry
Effect of grain pre‐treatment on different extractable phenolic groups in cereals and legumes commonly consumed in Tanzania
Authors: Towo Elifatio E , Svanberg Ulf , Ndossi Godwin D 
Published: July 2003

AbstractExtractable phenolic compounds, classified as total phenolics, resorcinols, catechols and galloyls, were determined in cereals and legume food grains commonly consumed in Tanzania, using various colorimetric methods. Grain samples of red sorghum (udo), finger millet, cowpea, mung bean and brown kidney bean were further processed—soaked in water at different pHs, germinated, cooked or dehulled (legumes only)—and the effect on extractable phenolics was analysed. In untreated grains, total phenolics ranged from 0.9 to 33.7, catechols from 0.8 to 13.5 and resorcinols from 0.2 to 11 mg catechin equivalents (CE) g−1. Galloyls (tannic acid equivalents, TAE) were found in negligible amounts in most grains, but in appreciable amounts in red sorghum (5.5 mg g−1). Processing of grains led to variable effects on the extractable phenolics. Soaking the grains significantly (p < 0.05) reduced the amount of total extractable phenolics in red sorghum, finger millet and cowpea, with alkali and acidic media being more effective. Water soaking had no effect on total extractable phenolics in mung bean and water, while alkali and acidic soaking had no effect on total extractable phenolics in brown kidney bean. Extractable catechols and resorcinols were affected by soaking in a similar pattern to total extractable phenolics. Germination reduced total extractable phenolics, catechols and resorcinols in all samples, except for catechols in mung bean. Cooking (boiling of grains) was more effective in reducing total extractable phenolics in cereals than germination and water soaking, while dehulling was the most effective method for reducing total extractable phenolics in legumes (p < 0.01). Copyright © 2003 Society of Chemical Industry
Translations from natural deduction to sequent calculus
Authors: von Plato Jan 
Published: July 2003

AbstractGentzen's “Untersuchungen” [1] gave a translation from natural deduction to sequent calculus with the property that normal derivations may translate into derivations with cuts. Prawitz in [8] gave a translation that instead produced cut‐free derivations. It is shown that by writing all elimination rules in the manner of disjunction elimination, with an arbitrary consequence, an isomorphic translation between normal derivations and cut‐free derivations is achieved. The standard elimination rules do not permit a full normal form, which explains the cuts in Gentzen's translation. Likewise, it is shown that Prawitz' translation contains an implicit process of cut elimination.
Sequent systems for compact bilinear logic
Authors: Buszkowski Wojciech 
Published: July 2003

AbstractCompact Bilinear Logic (CBL), introduced by Lambek [14], arises from the multiplicative fragment of Noncommutative Linear Logic of Abrusci [1] (also called Bilinear Logic in [13]) by identifying times with par and 0 with 1. In this paper, we present two sequent systems for CBL and prove the cut‐elimination theorem for them. We also discuss a connection between cut‐elimination for CBL and the Switching Lemma from [14].
Some results on Kripke models over an arbitrary fixed frame
Authors: Bagheri Seyed Mohammad , Moniri Morteza 
Published: July 2003

AbstractWe study the relations of being substructure and elementary substructure between Kripke models of intuitionistic predicate logic with the same arbitrary frame. We prove analogues of Tarski's test and Löwenheim‐Skolem's theorems as determined by our definitions. The relations between corresponding worlds of two Kripke models 𝒦 ⪯ 𝒦′ are studied.
Computable choice functions for computable linear orderings
Authors: Lerman Manuel , Watnick Richard 
Published: July 2003

AbstractA choice set for a computable linear ordering is a set which contains one element from each maximal block of the ordering. We obtain a partial characterization of the computable linear order‐types for which each computable model has a computable choice set, and a full characterization in the relativized case; Every model of the linear order‐type α of degree ≤ d has a choice set of degree ≤ d iff α can written as a finite sum of order‐types, each of which either has finitely many blocks, or has order‐type n · η for some integer n.
On the regular extension axiom and its variants
Authors: Rathjen Michael , Lubarsky Robert S. 
Published: July 2003

AbstractThe regular extension axiom, REA, was first considered by Peter Aczel in the context of Constructive Zermelo‐Fraenkel Set Theory as an axiom that ensures the existence of many inductively defined sets. REA has several natural variants. In this note we gather together metamathematical results about these variants from the point of view of both classical and constructive set theory.
New sequent calculi for Visser's Formal Propositional Logic
Authors: Ishii Katsumasa 
Published: July 2003

AbstractTwo cut‐free sequent calculi which are conservative extensions of Visser's Formal Propositional Logic (FPL) are introduced. These satisfy a kind of subformula property and by this property the interpolation theorem for FPL are proved. These are analogies to Aghaei‐Ardeshir's calculi for Visser's Basic Propositional Logic.
Developments in understanding the formation, structure and properties of polymer networks
Authors: Stepto R.F.T. , Cail J.I. , Taylor D.J.R. , Ward I.M. , Jones R.A. 
Published: July 2003

AbstractTwo areas of networks modelling are described. The first is concerned with the application of a Monte‐Carlo (MC) algorithm to account fully for loop formation in RA2 + R′B3 and RA2 + R′B4 polymerisations. The resulting interpretation of experimental elastic moduli of HDI‐based polyurethane (PU) networks prepared at different dilutions shows it is essential to account for elastic losses in loop structures of all sizes. An important parameter, x, is introduced, namely the average fractional loss of elasticity per larger loop structure relative to the loss per smallest loop structure. Application of the MC calculations to the formation and resulting structures of MDI‐based PU networks and poly(dimethyl siloxane) (PDMS) networks shows the competing effects of loop structures and chain interactions (PU) or topological entanglements (PDMS) on the modulus. The second area of networks modelling is the MC simulation of the elastic behaviour of chains in networks using realistic rotational‐isomeric‐state chain models. Stress‐strain and stress‐optical properties can be modelled quantitatively. In stress‐strain behaviour, an increase in the proportion of fully extended chains with increasing macroscopic strain causes a reduction in network modulus at moderate macroscopic strains. There is no need to invoke a transition from affine to phantom chain behaviour as deformation increases. For stress‐optical properties, the MC method gives, in agreement with experiment, values of stress‐optical coefficient that are dependent upon both deformation ratio and network‐chain length. Applications of the method to the quantitative modelling of the stress‐strain properties of PDMS networks and the stress‐optical properties of polyethylene and poly(ethylene terephalate) networks are described.
OCTA (Open Computational Tool for Advanced material technology)
Authors: Doi Masao 
Published: July 2003

AbstractOCTA (Open Computational Tool for Advanced material technology) is an integrated simulation system for polymeric materials developed by a joint project of industry and academia supported by Japanese government. It aims at exploring the utility of mesoscale modelings developed in polymer science. OCTA consists of four simulation engines (molecular dynamics engine, rheology engine, interface engine, multi‐phase engine) and a simulation platform. The system is designed to be open and extendable: all programs and source codes can be downloaded at http://octa.jp.
Supramolecular research by single molecule force spectroscopy
Authors: Cui Shuxun , Zhang Wenke , Xu Qiaobing , Wang Chi , Zhang Xi 
Published: July 2003

AbstractSingle molecule force spectroscopy (SMFS) is a new kind of technique based on atomic force microscope, which allows detecting force as low as pico‐newtons directly. Herein based on our recent work, we want to demonstrate the investigation of supramolecular structures and interactions in polymer systems by SMFS, such as desorption force between polymer and substrate, identifiability of polymer micelle and its interaction with surfactant, splitting force of ion‐induced helical structure in polysaccharide. It shows well that SMFS is a powerful tool in the study of supramolecular science.
Preparation of multihollow polymer particles by the alkali/cooling method under partial neutralization conditionsa)
Authors: Okubo Masayoshi , Okada Masahiro , Shiba Kenjin 
Published: July 2003

AbstractHeterogeneity in the formation of multihollow structure among submicron‐sized styrene‐methacrylic acid copolymer particles, which were produced by batch emulsion copolymerization, by the alkali/cooling method under partial neutralization of carboxyl groups was investigated. There was a threshold of the acid content to form the multihollow structure. The heterogeneity among the particles was based on the heterogeneity of the acid content among the original particles.
A study on hydrogen bonding in controlled‐structure benzoxazine model oligomers
Authors: Kim Ho‐Dong , Ishida Hatsuo 
Published: July 2003

AbstractThe synthesis procedure for controlled‐structure benzoxazine model oligomers is described. To understand the complex hydrogen bonding structure, a series of benzoxazine model oligomers is characterized by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FT‐IR). The NMR resonances for model oligomers are newly assigned. The FT‐IR spectra for model benzoxazine oligomers are carefully investigated both in crystalline and solution states. The distribution of hydrogen bonding species in benzoxazine model oligomers is quantitatively analyzed using FT‐IR spectra. The cyclic conformations for the oligomers are also proposed.
Nanometer scale mechanical study on well defined nanostructured chain aggregation of polyethylene
Authors: Du Binyang , Liu Jieping , Zhang Jian , Yang Decai , He Tianbai , Tsui Ophelia K.C. 
Published: July 2003

AbstractTwo kinds of polyethylene chain aggregation with chain axis perpendicular and parallel to the supported substrate were designed and successfully obtained from melt under an electric field and by melt‐drawn method, respectively. Their nanostructures were investigated by using transmission electron microscopy and atomic force microscopy. The chain modulus of the aggregations along and perpendicular to the chain axis were quantitatively measured to be 267 GPa and 13.8 GPa, respectively, by performing atomic force microscopy combining nanoindentation technique. This work provides new method to study polymer properties on the nanometer or molecular scale and insight into structure‐property relationship on the nanometer scale for polymers, which was usually established based on micro‐scale structure and macro‐scale property.
Progress in liquid chromatography of synthetic electroneutral polymers
Authors: Berek Dušan 
Published: July 2003

AbstractRecent achievements and anticipated future progress in high performance liquid chromatography of synthetic electroneutral polymers (polymer HPLC) are briefly reviewed. Basic retention mechanisms of polymer HPLC are explained and corresponding separation procedures are discussed. Advantages, drawbacks and pitfalls are presented of the most important polymer HPLC method, namely size exclusion chromatography. Principles of polymer HPLC methods combining various separation mechanisms within one chromatographic column (coupled procedures) or in a set of different chromatographic columns (two‐ and multi‐dimensional procedures) are outlined.
Macromolecular assembly: from irregular aggregates to regular nanostructures
Authors: Jiang Ming , Duan Hongwei , Chen Daoyong 
Published: July 2003

AbstractBased on our long‐term research on interpolymer complexation due to hydrogen bonding, we proposed several novel self‐assembly approaches to polymeric micelles with regular structures. Differing from micelles of block and graft copolymers, our micelles don't have any chemical bonds between the core and shell. In addition, some of these approaches have been proved to be effective to fabricate hollow aggregates.
Structure and dynamics of dendritic macromolecules
Authors: Ozerin Alexander N. , Muzafarov Aziz M. , Gordeliy Valentin I. , Kuklin Alexander I. , Ignat'eva Galina M. , Krykin Mikhail A. , Ozerina Lyudmila A. , Shumilkina Natalia A. , Islamov Akhmed Kh. , Sharipov Eugene Yu. , Mukhamedzyanov Ruslan I. 
Published: July 2003

AbstractThe highly branched regular organosilicon polymer structures (dendrimers) were examined. A number of experimental techniques were used to study the structure and dynamics of dendritic macromolecules in a bulk state as well as in diluted solutions. The reliable quantitative structural and dynamical characteristics, which were obtained within a framework of a complex investigation, arranged a background to resolve several of the contradictions in accounting for the results coming from the various experimental methods and numerical calculations. The explanations were found for: (a) why dendrimers look as penetrable and impenetrable with the solvent at the same time; (b) why dendrimers reveal typical for the linear polymers segmental relaxation spectra and possess a translation diffusion of the whole macromolecule in addition. The small‐angle neutron scattering experiments on the dendrimers with the specially labeled terminal groups showed that the terminal groups are concentrated near the periphery of the dendrimer structure.
Synthesis and optical properties of hyperbranched polyarylenes and linear polyacetylenes
Authors: Xie Zhiliang , Peng Han , Lam Jacky W.Y. , Chen Jumwu , Zheng Yonghua , Qiu Chengfeng , Kwok Hoi Sing , Tang Ben Zhong 
Published: July 2003

AbstractNew hyperbranched polyarylenes (HPAs) and linear polyacetylenes (LPAs) containing chromophoric moieties were synthesized in high yields (up to 97%) by coablt‐ and tantalum‐catalyzed polycyclotrimerizations and tungsten‐catalyzed metathesis polymerizations, respectively. The polymers possessed high molecular weights (Mw up to 113 000 Da) and were completely soluble in common organic solvents. The HPAs emitted strong UV light of 400 nm in high quantum yields (ΦF up to 0.98) and limited intense laser pulses, whose limiting threshold and signal suppress power were better than those of C60, a well‐known optical limiter. The electroluminescence (EL) devices of the LPAs emitted blue light of ∼460 nm and exhibited maximun brightness, current efficiency, and external quantum efficiency of 1118 cd/m2, 1.53 cd/A, and 0.85%, respectively.
Polymer dynamics of thin films and monolayers
Authors: Yu Hyuk 
Published: July 2003

AbstractSurface viscoelasticity of polymeric thin films and monolayers at the air/water interface can be deduced from the propagation characteristics of spontaneously generated capillary waves. The characteristics are probed by the technique of surface light scattering. It is shown that vinyl polymers with hydrophilic pendant groups and polyethers give rise to the predominantly elastic monolayers and thin films whereas those with relatively hydrophobic pendant groups the more viscous monolayers and thin films.
New trends in industrial polymer research
Authors: Schenck Hans Uwe 
Published: July 2003

AbstractIn the past decades a shift in paradigm took place in industrial polymer research. Only a few new polymers were developed based on new monomeric building blocks. The main focus is now on tailoring “new polymers” with well‐defined structure and properties based on a set of low cost “old” monomers using controlled polymerization mechanisms.
Self‐assembly in mixtures of block copolymers: “co‐surfactant effects” on morphology control
Authors: Hashimoto Takeji , Yamaguchi Daisuke , Court François 
Published: July 2003

AbstractWe found that competing long‐range interactions of the two block chains in their binary mixtures give intriguing effects on ordered microdomain structures. One effect is a co‐surfactant effect observed when the two blocks are mixed with their junctions on common interfaces, giving rise to such effects as (i) the two lamella‐forming block copolymers give hexagonal cylinders and consequently to the increase of the interface curvatures, or (ii) a short symmetric block copolymer mixed with a large asymmetric block copolymer effectively decreases the interface curvatures, depending upon composition and molecular weight of the short block copolymer. The other effect is the one which causes two blocks macroscopically phase‐separate into different ordered domains.
Photochemically‐induced refractive index and fluoresence patterning on polymer films
Authors: Horie Kazuyuki , Murase Seiichiro , Takahashi Satoshi , Teramoto Madoka , Furukawa Hidemitsu 
Published: July 2003

AbstractThe molecular design for large photo‐induced refractive index changes in transparent visible light region was proposed and realized with norbornadiene polymers and poly(vinyl cinnamate). The patterning of pure refractive‐index contract on their transparent films was made with near‐field scanning optical microscopy (NSOM). Reversible fluorescence patterning on polymer films is also presented by using controlled energy transfer from a fluorescent pyromethene to a photochromic diarylethene.
Surface friction of polyelectrolyte gels
Authors: Gong Jian Ping , Kagata Go , Osada Yoshihito 
Published: July 2003

AbstractThe friction between two chemically cross‐linked polyelectrolyte gels carrying the same sign of charges has been investigated in pure water as well as in salt solutions using a rheometer. It is found that the friction was largely dependent on the charge densities of the gel surface and the ionic strength of the aqueous solution. The chemical structures of the polyelectrolyte gels also play an important role. The friction is described in terms of the hydrodynamic lubrication of the solvent layer between the two gel surfaces, which is formed due to the electrostatic repulsion of the two gel surfaces. The thickness of the solvent layer has been estimated using the Poisson‐Boltzmann equation supposing that the ionic osmotic pressure is balanced by the normal pressure applied on the gel. The friction values have been calculated by considering the shear flow of solvent in gel region using the Debye‐Binkman equation. For strongly charged polyelectrolyte gels swollen in pure water, the theoretical analysis shows that the friction coefficient almost has no dependence on the water content of the gel, which well agrees with the experimental observations.
Highly conducting graphitic carbon films and nano patterns from poly(p‐phenylenevinylene) prepared on the surface of silicon wafers by the CVD method
Authors: Kim Kyungkon , Zhong Guolun , Jin Jung‐Il 
Published: July 2003

AbstractWe could prepare highly electrically conducting graphitic carbon films and nano patterns by carbonizing the poly(p‐phenylenevinylene) (PPV) films and nano patterns prepared on the silicon surface by the chemical vapor deposition polymerization method of α,α'‐dichloro‐p‐xylene. When the PPV films on silicon wafers were thermally treated at 850°C highly oriented graphitic carbon films were obtained which exhibit an electrical conductivity higher than 0.7 x 103 Scm−1. This conductivity value is more than 10 times the value for the carbon films obtained from bulk PPV films or glassy carbons heat treated at the same temperature. Moreover, nano patterns of graphitic carbons were easily obtained on silicon wafers through carbonization of nano patterned PPV obtained by the CVD polymerization method.
Excimer suppression mechanism in light emitting polymer blends
Authors: Yu J.‐W. , Kim J.K. , Kim D.Y. , Kim C.H. , Song N.W. , Kim D. , Kim C.Y. 
Published: July 2003

AbstractAlternating copolymer of distyrylenediethylhexyloxyphenylene and phenyltriazine(PPVT) or hydroxyphenyltriazine(PVOT) is synthesized in order to enhance the electron mobility in the light emitting polymers. Photoluminescence(PL) spectrum of PPVT shows excimeric characteristics but PVOT generates excitonic PL emission. A blend of PVOT with polyvinylcarbazole(PVK) enhances the PL intensity of PVOT on photoexcitation of PVK indicating an efficient energy transfer. The excimeric PL emission of PPVT is suppressed on photoexcitation of a blend with PVK at the UV‐visible absorption(AB) maximum of PVK, which is an indirect photoexcitation, while the energy transfer from PVK to PPVT is not completed.