bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stochastic dynamic systems with complex‐valued eigensolutions
Authors: Rahman Sharif 
Published: January 2007

AbstractA dimensional decomposition method is presented for calculating the probabilistic characteristics of complex‐valued eigenvalues and eigenvectors of linear, stochastic, dynamic systems. The method involves a function decomposition allowing lower‐dimensional approximations of eigensolutions, Lagrange interpolation of lower‐dimensional component functions, and Monte Carlo simulation. Compared with the commonly used perturbation method, neither the assumption of small input variability nor the calculation of the derivatives of eigensolutions is required by the method developed. Results of numerical examples from linear stochastic dynamics indicate that the decomposition method provides excellent estimates of the moments and/or probability densities of eigenvalues and eigenvectors for various cases including large statistical variations of input. Copyright © 2007 John Wiley & Sons, Ltd.
Free hanging membrane model for shell structures
Authors: Brew J. S. , Lewis W. J. 
Published: January 2007

AbstractThe paper presents a form‐finding methodology based on a concept of a free hanging membrane (FHM). The numerical model of the membrane assumes that the material is inextensible, resists tension, has a specified area, but no fixed shape. The development of the numerical model has been motivated by a form‐finding process aimed at predicting natural forms of shell structures, a process originally based on physical experiments involving a creation of hanging models made of fabric or chains. As demonstrated by the experimental work of Swiss designer, Heinz Isler, the inverted shapes of hanging membrane models give, within the limitations of fabric properties, perfect shell structures, the shapes of which can be scaled up to a full‐size construction. The physical modelling process, however, is expensive and time consuming. The numerical alternative proposed here has a number of advantages. The FHM's mechanical properties are deduced and its application to form‐finding of hanging fabric models (inverted shell structures) is presented. It is shown, in cases where such configurations can be analysed, that the achieved shapes are minimum energy configurations. A number of examples of form finding are presented which show that the method is accurate and efficient. Copyright © 2007 John Wiley & Sons, Ltd.
Application of atmospheric pressure chemical ionisation mass spectrometry in the identification and differentiation of Panax Species
Authors: Leung Kelvin Sze‐Yin , Chan Kelvin , Bensoussan Alan , Munroe Mary J. 
Published: January 2007

AbstractAn HPLC‐MS method using an atmospheric pressure chemical ionisation (APCI) source has been developed to assist in the differentiation of three ginseng species: Panax quinquefolium (American ginseng), P. ginseng (Chinese ginseng) and P. notoginseng (sanqi) species. The differentiation method relies on the identification of ginsenosides Rf and F11, and notoginsenoside R1. R1 is observed in both P. notoginseng and Chinese ginseng, whilst F11 is found exclusively in the American species. The presence of these compounds permits the definitive identification of the species to be made. The APCI ionisation source has been employed to tackle the matrix interference in analysing Chinese medicinal materials and to minimise the associated matrix effects that are commonly encountered with other ionisation modes. Moreover, the method allows direct interface to conventional HPLC systems. More importantly, chemical reference standards of ginsenosides are not required in this method. This technique provides an alternative approach to analysing high molecular weight polar compounds that typically encountered in complex matrices of Chinese medicinal materials. Copyright © 2006 John Wiley & Sons, Ltd.
Environmentally friendly photosensitizer: starch modified with chlorophyll‐type chromophores
Authors: Nowakowska Maria , Zapotoczny Szczepan , Sterzel Monika 
Published: January 2007

AbstractA novel water‐soluble polymeric photosensitizer (SPheo) based on starch and containing pheophorbide (Pheo), a chlorophyll‐derived chromophore, was synthesized and its photophysical and photochemical properties were studied. Pheo chromophores attached to the polymeric chains of starch absorb light of the UV‐visible spectral region. The clustering of hydrophobic Pheo chromophores results in the formation of hydrophobic microdomains in aqueous solution where organic molecules can be solubilized. SPheo polymer efficiently photosensitizes reactions mediated by energy and/or electron transfer from the electronically excited chromophores to the molecules of organic compounds solubilized in polymeric microdomains or residing in water. Copyright © 2007 Society of Chemical Industry
Reactivity of quinones for the dehydrogenation of poly(1,3‐cyclohexadiene)
Authors: Natori Itaru , Sato Hisaya 
Published: January 2007

AbstractThe reactivity of three types of quinones (3,4,5,6‐tetrachloro‐1,2‐(o‐)‐benzoquinone (TOQ), 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ), and 2,3,5,6,‐tetrachloro‐1,4‐(p‐)‐benzoquinone (TCQ)) was examined for the dehydrogenation of poly(1,3‐cycohexadiene) (PCHD) composed of 1,2‐cyclohexadiene and 1,4‐cyclohexadiene units. The order of reactivity was TOQ > DDQ > TCQ. The steric hindrance of CO groups in the quinones appeared to be an important factor in determining their reactivity. DDQ was found to be an appropriate dehydrogenation reagent for PCHD. The reactivity of TCQ was considerably low for PCHD containing 1,2‐cyclohexadiene units. The reactivity of TOQ was too high and side reactions occurred, causing the formation of structural defects. Copyright © 2007 Society of Chemical Industry
Identification of bactenecin‐1 in cervicovaginal fluid by two‐dimensional electrophoresis in an ovine model of preterm labour
Authors: Young I. Ross , Rice Gregory E. , Palliser Hannah K. , Ayhan Mustafa , Dellios Nicole L. , Hirst Jonathan J. 
Published: January 2007

AbstractPreterm labour is a major problem in obstetrics. Timely intervention with available treatments is hampered by the lack of a reliable test of imminent preterm delivery. Current methods of diagnosis are based on the detection of breakdown products of foetal membranes or structural changes to the cervix when preterm labour is well established. The aim of this study was to screen the cervicovaginal fluid (CVF) proteome to identify labour‐associated proteins that could be used as markers of imminent preterm delivery. Labour was induced in sheep at 135 days of gestation (term 147 days) by foetal infusion of dexamethasone (1 mg/24 h). CVF samples were collected before and 28 h after the start of infusion as well as at delivery (58.7 ± 1.9 after the start of infusion, n = 5). One protein that was upregulated eight‐fold, was bactenecin‐1, a member of the cathelicidin family of antimicrobial proteins. This antimicrobial protein warrants further investigation as a marker of preterm labour, particularly during the period after the initiation of labour but before there is marked cervical connective tissue breakdown.
Differential expression of sarcoplasmic proteins in four heterogeneous ovine skeletal muscles
Authors: Hamelin Muriel , Sayd Thierry , Chambon Christophe , Bouix Jaques , Bibé Bernard , Milenkovic Dragan , Leveziel Hubert , Georges Michel , Clop Alex , Marinova Penka , Laville Elisabeth 
Published: January 2007

AbstractFiber‐type distribution is known to vary widely within and between muscles according to differences in muscle functions. 2‐DE and MALDI‐MS were used to investigate the molecular basis of muscle fiber type‐related variability. We compared four lamb skeletal muscles with heterogeneous fiber‐type composition that are relatively rich in fast‐twitch fiber types, i.e., the semimembranosus, vastus medialis, longissimus dorsi, and tensor fasciae latae (TL). Our results clearly showed that none of the glycolytic metabolism enzymes detected, including TL which was most strongly glycolytic, made intermuscular differentiation possible. Muscle differentiation was based on the differential expression of proteins involved in oxidative metabolism, including not only citric acid cycle enzymes but also other classes of proteins with functions related to oxidative metabolism, oxidative stress, and probably to higher protein turnover. Detected proteins were involved in transport (carbonate dehydratase, myoglobin, fatty acid‐binding protein), repair of misfolding damage (heat shock protein (HSP) 60 kDa, HSP‐27 kDa, alpha‐crystallin beta subunit, DJ1, stress‐induced phosphoprotein), detoxification or degradation of impaired proteins (GST‐Pi, aldehyde dehydrogenase, peroxiredoxin, ubiquitin), and protein synthesis (tRNA‐synthetase). The fractionating method led to the detection of proteins involved in different functions related to oxidative metabolism that have not previously been shown concomitancy.
Covalently attached graft polymer monolayer on organic polymeric substrate via confined surface inhibition reaction
Authors: Yang Peng , Xie Jingyi , Yuan Jing , Zhang Li , Liu Weina , Yang Wantai 
Published: January 2007

AbstractA grafting technique was proposed for the preparation of polymer monolayer on polymeric substrate. On the basis of our recent work on polymer‐supported inhibitor (PSI), hydroquinone (HQ) was first implanted onto polypropylene (PP) surface through UV‐initiated grafting. The resulting immobilized HQ was used as PSI for the thermal‐induced free radical polymerization (FRP) of acrylic acid (AA). The inhibition mechanism was similar to that of free HQ molecule, that is, polymer chain‐carrying radical or peroxy radical could be deactivated by abstracting hydrogen atom from hydroxyl group of immobilized HQ, and the resulting oxyradical (semiquinone radical) combined with another active chain free radical. According to this mechanism, a devised redox initiator consisting of sodium hydrogen sulfite and ammonium persulfate was used to initiate FRP of AA in water at low temperature (50 °C). High crystalline biaxial oriented PP film with HQ immobilized was deliberately laid in this system as a radical trap to capture poly(acrylic acid) (PAA) short chain radical. Through X‐ray photoelectron spectra (XPS) analysis it was found that the atom ratio of CHQ (carbon in HQ) to CCOOH (carbon in COOH) decreased with prolonging polymerization time and became stable after about 30 min. The formed PAA short chain on the surface showed a distribution of monolayer, and the saturated thickness was calculated as 5–7 Å. The degree of polymerization of graft chain in PAA monolayer was estimated as 15–20 through three different models. Relating to surface coverage being 100% in ideal densely packed PAA monolayer, real monolayer surface coverage in such reaction system was estimated as 12.3–18.5%. This method was expected to give us a general approach for constructing kinds of graft polymer monolayer on polymeric substrate, because the involved chemistry was only common inhibition reaction between immobilized inhibitor (HQ) and FRP system in solution (herein redox initiating system of AA). We named this grafting chemistry as confined surface inhibition reaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 745–755, 2007
Constitutive modeling for characterizing the compressive behavior of PMMA open‐cell foams
Authors: Jo Choonghee , Fu Jin , Naguib Hani E. 
Published: January 2007

AbstractA constitutive model for evaluating the compressive behavior of Poly(methyl‐methacrylate) (PMMA) open‐cell foams is herein proposed. Specifically, the study investigates the viscoelastic and viscoplastic behaviors of the PMMA open‐cell foams. The constitutive equation is expressed in terms of the following polymer and foam properties: elastic modulus, relative density, as well as the relaxation and densification constants. PMMA open‐cell foams are manufactured using a gas foaming/particulate leaching method and uniaxial compression tests are performed. The mechanical properties and compressive stress‐strain responses obtained from the experiments are compared with those predicted by the proposed constitutive model. The results suggest that the constitutive model is an apt one for assessing and evaluating the compressive behaviors of PMMA open‐cell foams. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 436–443, 2007
Polymer blend for fuel cells based on SPEKK: Effect of cocontinuous morphology on water sorption and proton conductivity
Authors: Lavorgna Marino , Mensitieri Giuseppe , Scherillo Giuseppe , Shaw Montgomery T. , Swier Steven , Weiss Robert A. 
Published: January 2007

AbstractProton‐exchange membranes (PEM), suitable for micro and small sized fuel cells, were obtained by blending sulfonated poly(ether ketone ketone) (SPEKK) polymers with different ionic exchange capacity (IEC). This approach was used to limit the amount of swelling caused by water sorption without significantly decreasing the proton conductivity of the membrane. In particular a membrane with a cocontinuous biphasic morphology was obtained by blending two SPEKKs, with respectively, an IEC equal to 1.2 and 2.08 in the weight ratio 60/40, casted from 5% (w/v) solutions in dimethylacetamide. The effect of a cocontinuous morphology on water sorption and proton conductivity in comparison to neat SPEKK was investigated. In the range of temperatures between 40 and 70 °C, which is typical for small and micro fuel cells conditions, it was found that the ratio of proton conductivity to water sorption could be maximized. This has been attributed to the presence of percolative pathways for proton transport provided by the cocontinuous morphology along with the constraint effect of the less sulfonated component on the overall capacity of swelling of the membrane. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 395–404, 2007
Determination of selenosugars in crude human urine using high‐performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Letsiou Sophia , Nischwitz Volker , Traar Pedro , Francesconi Kevin A. , Pergantis Spiros A. 
Published: January 2007

AbstractThe narrow gap between essentiality and toxicity of selenium requires detailed investigations on selenium metabolism in order to find suitable indicators for the selenium status in the human body. Current methods for quantitative selenium speciation in human urine are based on separation by high‐performance liquid chromatography (HPLC) coupled online with elemental mass spectrometry (MS), and the potential of molecular MS detection techniques for the reliable identification and quantification of selenosugars in crude human urine has not been utilized. Now we report the development of an HPLC tandem mass spectrometric (MS/MS) method for the reliable determination in crude human urine of three significant selenium urinary metabolites, collectively termed selenosugars, namely methyl 2‐acetamido‐2‐deoxy‐1‐seleno‐β‐D‐galactopyranoside (SeGalNAc), methyl 2‐acetamido‐2‐deoxy‐1‐seleno‐β‐D‐glucopyranoside (SeGluNAc) and methyl 2‐amino‐2‐deoxy‐1‐seleno‐β‐D‐galactopyranoside (SeGalNH2). Reversed‐phase HPLC, with and without cation‐exchange guard columns, was applied for the separation of the selenosugars, and atmospheric pressure chemical ionization (APCI) and selected reaction monitoring (SRM) were used for selective and sensitive detection. The collision‐induced dissociation behaviour of the selenosugars was studied in detail using APCI triple quadrupole MS/MS and electrospray ion trap MS. The developed method was applied to urine samples collected prior to and after selenium supplementation for the quantification of SeGalNAc using both external calibration and the method of standard additions. Additionally, SeGalNH2 was detected in urine samples after Se supplementation. Finally, neutral loss scanning was explored as a possible method for the detection of unknown methyl‐selenosugars. Copyright © 2007 John Wiley & Sons, Ltd.
Simulation of high‐ and low‐resolution mass spectra for assessment of calibration methods
Authors: Turner Phillip G. , Taylor Steve , Goulermas John Y. , Hampton Kim 
Published: January 2007

AbstractCalibrating mixtures of residual gases in quadrupole mass spectrometry (QMS) can be difficult since low m/z ratios of molecular ions and their fragments result in overlap of signals especially in the lower mass regions. This causes problems in univariate calibration methods and encourages use of full spectral multivariate methods. Experimental assessment of regression methods has limitations since experimental sources of error can only be minimised and not entirely eliminated. A method of simulating full spectra at low and high resolution to accurate masses is described and these are then used for a calibration study of some popular linear regression methods [classical least squares regression (CLS), partial least squares (PLS), principal component regression (PCR)]. Copyright © 2007 John Wiley & Sons, Ltd.
Continuity of vegetation in space and time: A comparison of insects' habitat templet in different successional stages
Authors: Southwood T. R. E. , Brown V. K. , Reader P. M. 
Published: January 2007

Conslusions and SummaryThis paper shows how dynamic are patterns of host plant distribution in space and time and indicates methods of assessing these features of the habitat templet that will play a major role in the evolution of the optimal migratory (sensu lat.) strategy.The actual spatial patterns of host plants vary according to the growth form, environmental tolerance and propagule dispersal of the particular species. This study was not sufficiently extensive to detect trends in these features in relation to successional age. However, the length of time the host plant remains in the same location (H in the calculation of durational stability=H/τ), increases with the successional age of habitat, as does the size of patches of hsot plants, particularly when these are due to modular growth. Therefore the probability of an insect being able to oviposit on or near the host plant on which it fed as a larva increases with the successional age of the habitat.
Crystallization of Indian beef tallow fatty acids from aqueous ethanols
Authors: Subrahmanyam V. V. R. , Achaya K. T. 
Published: January 2007

SummaryCrystallization of Indian beef tallow fatty acids (total saturated acid content 64.3% by wt.) from six dilutions of ethanol (95 to 70%) at five temperatures (20° to −12.5°C.) and at six solvent/acid ratios (2.5 to 20) was systematically studied. Optimum conditions of choice would use 85% ethanol at −12.5°C. at a solvent/acid ratio to 10 to give 69.7% precipitated acids, I.V. 11.0, and 30.3% soluble acids, I.V. 93.5. Other conditions of a similar order are possible. The comparatively saturated character of Indian beef tallows and the use of ethanol cause a departure from the Emersol process operating conditions using methanol, which is designed for American tallows. Considerations bearing on large‐scale application are discussed.
The hydrogenation of fatty oils with palladium catalyst. I. Hydrogenation of castor oil
Authors: Zajcew Mykola 
Published: January 2007

SummaryA good quality of castor wax was prepared in the laboratory at 100°C. and 45 p.s.i.g., using a modified palladium catalyst. The product obtained had an iodine value of 4, a hydroxy value of 145, and acid value of 1.8, and a capillary melting point of 86°.
Identification of elementary sulfur and sulfur compounds in lipid extracts by thin‐layer chromatography
Authors: Murphy Mary T. J. , Nagy Bartholomew , Rouser George , Kritchevsky Gene 
Published: January 2007

AbstractElementary sulfur, long chain thiols and sulfides in lipid mixtures can be separated and identified by thin layer chromatography (TLC), preparation of derivatives, development of typical flourescent colors with Rhodamine 6G under ultraviolet light, and colors with other spray reagents. Silica gel mixed with magnesium silicate and the same adsorbent plus silver nitrate are used for polar stationary phase and silver nitrate complexing chromatography, respectively.Elementary sulfur yields a purple fluorescent spot with Rhodamine 6G in contrast to the yellow fluorescent of most lipids. Compounds isolated by means of TLC were further identified by spectroscopic methods. The sulfur bacterium (Chromatium sp.), and the Orgueil carbonaceous meteorite were analyzed by the new technique. Elementary sulfur was identified in both samples, but the lipid compositions of the bacteria and meteorite were found to be entirely different. The meteorite lipids and hydrocarbons were also different from the abiological hydrocarbons synthesized in a Miller high frequency spark discharge experiment.The new analytical technique is suitable for the analysis of recent biological matter, petroleum, bitument and organic matter from marine sediments.
Determination of structure of unsaturated fatty acid positional isomers
Authors: Stein R. A. 
Published: January 2007

AbstractThe methods for determining the positions of unsaturation in fatty acids are reviewed. Overoxidation and isolation problems germane to permanganate oxidations, and the formation of by‐products and attack of solvents during ozonolysis are considered. The applicability of mass, nuclear magnetic and infrared spectral data to the problem of locating positions of unsaturation is discussed.
Determination of oxirane content of derivatives of fats
Authors: Maerker Gerhard 
Published: January 2007

AbstractAlthough oxirane functions react readily with a large variety of chemical reagents, no single analytical method has been universally successful in measuring the oxirane content of all epoxides. This failure is ascribable to the manner in which the chemical reactivity of the three membered cyclic ethers is modified by molecular structure and by the presence of nearby substituents.A survey of the various types of published analytical methods is given, but major emphasis is placed upon a discussion of procedures applicable to the analysis of epoxy derivatives of fats. Most of these latter methods depend upon the addition of some reagent, HX, to the epoxide ring with simultaneous cleavage of a carbon‐oxygen bond.
Integrated processing of peanut for the separation of major constituents
Authors: Subrahmanyan V. , Bhatia D. S. , Kalbag S. S. , Subramanian N. 
Published: January 2007

SummaryBench‐scale experiments were carried out on the processing of peanut by a new method. The decuticled kernels were pasted, and the paste was subjected to the Skipin process to recover approximately 30% oil; the residual paste was made into a dispersion at 10.0 pH and clarified to get a carbohydrate meal (15.7% moisture‐free); the clarified dispersion was centrifuged to obtain another 12% fat and the remaining dispersion was acidified to get the protein (21.9% moisture‐free).Fifteen batches of 100‐1b. (45.4 kg.) each have been processed, and the reproducibility of the yields has been ascertained. The scope for increasing the oil yield and for improving protein quality is discussed.
Colorimetric determination of urease activity in soybean meals
Authors: Schramm Guenter , Aines Philip D. 
Published: January 2007

SummaryA quantitative method for the determination of urease activity in soybean meals is described. The procedure is based on the incubation of the meal sample with a known amount of urea, followed by colorimetric determination of the urea with p‐dimethylaminobenz‐aldehyde after incubation. Urease activity is expressed as the amount of urea decomposed under the specified conditions. The test is both accurate and specific for urease. The method is very reproducible and sensitive, especially at low urease activities.