bluuebunny/crossref_metadata_2025_split huggingface dataset:
A critical review of the pharmacology of the plant extract of Pygeum africanum in the treatment of LUTS
Authors: Edgar Alan D. , Levin Robert , Constantinou Christos E. , Denis Louis 
Published: March 2007

AbstractDespite an unremitting increase in the number of patients presenting symptoms of benign prostate hyperplasia (BPH), the viable treatment options remain relatively limited when compared to other disorders of aging. This has spurred an interest in so‐called alternative medicines, many of which continue to be used in spite of the more recent emergence of rationally targeted therapies. Nonetheless, in the case of plant extracts, the vast majority of these have not been subjected to the same rigorous pre‐clinical pharmacological testing and large‐scale clinical trials now required by health authorities. Furthermore, demonstration of their clinical efficacy in BPH has been hindered by trials of limited duration with a high placebo response. Beginning with a preliminary demonstration of in vitro inhibition of growth factor‐mediated fibroblast proliferation with Pygeum africanum extract, a detailed series of in vitro and in vivo studies on prostate growth and bladder function were undertaken. These studies, reviewed herein, have permitted the identification of putative molecular targets of Pygeum africanum extract affecting both growth factor‐mediated prostate growth as well as specific parameters of bladder function. These results, corroborated in part by short‐term clinical efficacy, set the stage for a large‐scale clinical trial to investigate the efficacy of Pygeum africanum extract in the treatment of lower urinary tract symptoms. Neurourol. Urodynam. 26:458–463, 2007. © 2007 Wiley‐Liss, Inc.
Alternating direction finite volume element methods for 2D parabolic partial differential equations
Authors: Wang Tongke 
Published: March 2007

AbstractOn the basis of rectangular partition and bilinear interpolation, this article presents alternating direction finite volume element methods for two dimensional parabolic partial differential equations and gives three computational schemes, one is analogous to Douglas finite difference scheme with second order splitting error, the second has third order splitting error, and the third is an extended locally one dimensional scheme. Optimal L2 norm or H1 semi‐norm error estimates are obtained for these schemes. Finally, two numerical examples illustrate the effectiveness of the schemes. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Analysis and finite element simulations of a second‐order fluid model in a bounded domain
Authors: Arada Nadir , Correia Paulo , Sequeira Adélia 
Published: March 2007

AbstractThis article is concerned with the equations governing the steady motion of a viscoelastic incompressible second‐order fluid in a bounded domain. A new proof of existence and uniqueness of strong solutions is given. In addition, using appropriate finite element methods to approximate a coupled equivalent problem, sharp error estimates are obtained using a fixed point argument. The method is applied to the two‐dimensional lid‐driven cavity problem, at low Reynolds number and in a certain range of values of the viscoelastic parameters, to analyze the combined effects of inertia and viscoelasticity on the flow. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007
Pyrolysis study of bromo‐ and chloroethyl benzenes in micropulse and flow reactors
Authors: Daren Stephen , Levy Moshe , Vofsi David 
Published: March 2007

AbstractThe pyrolytic and catalytic dehydrobromination of 2‐bromoethyl bromobenzene was studied as a step in the production of bromostyrene. The studies were carried out in a micropulse reactor attached to a gas chromatograph and in a number of ordinary flow reactors. Most of the work was carried out on 2‐Cl and 2‐Br ethyl benzene as model compounds. Catalytic effects of metals, oxides and molten salts were found. The pyrolytic reaction in the micropulse and flow reactors proved to be much faster than expected from the literature data on the monomolecular elimination studied in static systems. The addition of peroxides accelerates the reaction further and results in high conversions and high purity monomers at relatively low temperatures.
Inorganic oxide glasses as ionic polymers
Authors: Ray Neil H. 
Published: March 2007

AbstractOxide glasses can be regarded as network polymers consisting of oxygen atoms linked through multivalent atoms such as boron, silicon and phosphorus, and many of their properties can be related to two simple parameters of the network; the crosslink density and the packing density of oxygen atoms. The effects of changes in composition on the transformation temperatures of phosphate, borate, and borophosphate glasses can be rationalised in terms of these two network parameters.
Shish kebab formation on polyethylene monofilaments
Authors: Smith Paul , Pennings Albert J. 
Published: March 2007

AbstractA study has been made on skin formation of melt spun polyethylene monfilaments, which were solidified in air or in cold solvents and non‐solvents. Application of air or non‐solvents, such as water and acetone, as cooling media induced spherulitic crystallisation of the polymer, as was revealed in the scanning electron microscope. When the flowing polyethylene melt was quenched in good solvents, a 0.5 mm thick layer of lamellar or shish kebab structures developed on the polymeric fibres. It was established that shish kebabs were formed when the solvents, in which the polymer filament was quenched, were boiling during this solidification process.
Synthesis and characterisation of fluorine‐containing poly α‐esters. II. Thermal and hydroxyl‐initiated polymerisation of pentafluorophenyl‐substituted anhydrosulphites and anhydrocarboxylates of α‐hydroxycarboxylic acids
Authors: Smith Ian J. , Tighe Brian J. 
Published: March 2007

AbstractThe use of anhydrosulphite and anhydrocarboxylate derivatives of α‐pentafluorophenyl‐α‐hydroxypropanoic acid as precursors in the formation of fluorine‐containing poly α‐esters is described. Kinetic studies have enabled the nature of the competing mechanisms to be determined and compared with those occurring in the hydrocarbon analogues. The pentafluorophenyl group markedly enhances the susceptibility of both ring systems to hydroxyl‐initiated polymerisation and in the case of the anhydrocarboxylate this is the only viable polymerisation mechanism under the conditions described here. Although polymerisation of the anhydrosulphites is possible, purification of both the phenyl, and especially the pentafluorophenyl substituted monomer, is more difficult than in the case of either alkyl substituted anhydrosulphites or phenyl and pentafluorophenyl substituted anhydrocarboxylates. For this reason anhydrocarboxylate polymerisation represents the preferred route to pentafluorophenyl substituted poly α‐esters. The characterisation of the polymers produced is discussed.
Influence of non‐ionic surfactant on the stability of styrene—acrylonitrile copolymer latices
Authors: Ono Hiroshi , Jidai Eiki 
Published: March 2007

AbstractStyrene–acrylonitrile copolymer latices were prepared by emulsion polymerisation using sodium lauryl sulphate as emulsifier and potassium persulphate as initiator. The effect of polyoxyethylene nonyl phenyl ether on the stability of these copolymer latices has been investigated using magnesium chloride as a flocculating agent by measuring the rates of flocculation in the presence of various concentrations of surfactant. The values of the critical coagulation concentration (c.c.c.) were found to increase with increasing surfactant concentration for all latices. The rates of increase in c.c.c. with increasing surfactant concentrations were found to increase uniformly with increase in the content of acrylonitrile. The electrophoretic behaviour of these latices in the presence of surfactant has also been investigated. The values of mobilities at c.c.c. were found to decrease with increasein concentration of surfactant.
Thermal degradation of some perfluoroalkylene‐linked polymers
Authors: Cotter John L. , Knight Graham J. , Wright Walter W. 
Published: March 2007

AbstractPoly (1,3‐phenylenehexafluorotrimethylene) and perfluoroalkylene‐linked polyanhydride, polycarbonate and polyester have been studied by thermogravimetry, pyrolysis–gas chromatography–mass spectrometery and fluoride ion analysis. The thermal stability is governed by the ease of formation of specific cyclic degradation products.
Application of gel permeation chromatography to the study of shear degradation of polymeric viscosity index improvers used in automotive engine oils
Authors: Hillman Donald E. , Lindley Helen M. , Paul John I. , Pickles Donald 
Published: March 2007

AbstractGel permeation chromatography (g.p.c.) was used to monitor the degradation of polymeric viscosity index improvers in multigrade oils when subjected to mechanical shear using a Kurt Orbahn diesel injector rig. These tests are normally evaluated by measurement of viscosity of the oils before and after shear. For model systems of a base oil containing each of ten viscosity index improvers there is good correlation between viscosity and chromatography results. Tests on a multigrade oil subjected to sonic shear showed that g.p.c. can be used to follow qualitatively the degradation of one polymeric additive in the presence of another.
The thermal decomposition of some polyurethane foams
Authors: Chambers John , Reese Colin B. 
Published: March 2007

AbstractPolyurethanes exposed to fire conditions might generate decomposition products which would be responsible for a significant part of the toxicity of the fire gases.Polyurethanes have been prepared from a commercial mixture of tolylene‐2, 4‐ and 2,6‐di‐isocyanates, pure tolylene‐2,4‐di‐isocyanate, pure tolylene‐2,6‐di‐isocyanate and pure m‐phenylene di‐isocyanate. All polymers except that prepared from tolylene‐2,6‐di‐isocyanate were obtained as flexible foams. When each polyurethane was heated at 300°C in a stream of nitrogen, a sublimate was obtained. The sublimates were all apparently polymers derived from the di‐isocyanate rather than from the diol constituents of the polyurethanes. Pyrolysis of these materials at high temperatures (800–1000°C) led to similar mixtures of volatile products: at 1000°C the most abundant nitrogenous product, in each case, was hydrogen cyanide.
A proton magnetic resonance study of the self‐condensation of formaldehyde
Authors: Jones R. G. , Kodama Y. 
Published: March 2007

AbstractThe self‐condensation of formaldehyde in heavy water (D2O) has been studied against the more general background of the urea—formaldehyde system. Proton magnetic resonance data are reported for monomethylol urea (MMU), dimethylol urea, methylolbisurea (MBU) and solutions of formaldehyde in D2O at various concentrations over a limited temperature range. The results for formaldehyde lead to disagreement with the statistical interpretation of previous workers. The more accurate n.m.r. data presented here fit the random difunctional polycondensation model with a single parameter, within experimental, error, in contrast to the two needed by other authors.
The design of polymers for contact lens applications
Authors: Tighe Brian J. 
Published: March 2007

AbstractThe use of thermoplastics, elastomers and hydrogel polymers in contact lens applications is discussed in terms of the balance of properties required for the lens to function in a satisfactory manner. Although there are several thermoplastics that would appear to offer advantages over poly(methyl methacrylate), the most widely used polymer, the inherent disadvantages are in each case too great. The clarity, toughness, physiological inactivity and ease of fabrication are shared by many polymers, but its critical surface tension governing as it does the maintenance of a coherent tear film on the lens surface is unique amongst materials that are otherwise acceptable.The development of hydrogel polymers is discussed in terms of the potential use of this group of polymers in lenses designed for continuous as distinct from daily wear. The specific requirements of such a lens are considered in the light of the properties possessed by the cornea. Apart from the optical properties of thin (∼0.2 mm) sections of material, the most important parameters are oxygen permeability (since the cornea is avascular a relatively high permeability is required), mechanical properties (the material must be soft enough to avoid discomfort but rigid enough to resist deformation during eyelid movement) and surface hydrophilicity (most conveniently described in terms of the critical surface tension phenomena).
Characterization of interfacial solvent in protein complexes and contribution of wet spots to the interface description
Authors: Teyra Joan , Pisabarro M. T. 
Published: March 2007

AbstractWater networks in protein interfaces can complement direct interactions contributing significantly to molecular recognition, function, and stability of protein association. Thus, water can be seen as an extension or addition of protein structural features, which may add plenty of information to protein interfacial definition. However, solvent is frequently neglected in protein interaction studies. Analysis of the interfacial information contained in the PDB is essential to achieve more accurate descriptions of protein interfaces. With this aim, we have used the SCOWLP database (http://www.scowlp.org) and applied computational geometry methods to extract and analyze interfacial information of a high‐resolution nonredundant dataset of 176 protein complexes containing obligate and transient interfaces. We have identified all interfacial residues and characterized them in terms of temperature factors, secondary structure, residue composition, and pairing preferences to understand their contribution to the interface description. We have paid special attention to water‐bridged residues; focusing on those that interact only mediated by a water molecule called wet spots. Our results show that 40.1% of the interfacial residues are interacting through water and that wet spots represent a 14.5% of the total, emphasizing the importance of the inclusion of solvent in protein interaction studies, and the contribution of wet spots to interfacial description. Wet spots present similar characteristics to residues binding buried water molecules in the core or cavities of proteins; being preferably located in nonregular secondary structures and establishing hydrogen bonds by their main‐chains. We observe that obligate and transient interfaces present a comparable amount of solvent. Moreover, the role of solvent in both complex types differs according to the different nature of their interfaces. The information obtained in our studies will assist in the process of accomplishing more accurate descriptions of protein interfaces and may be helpful to improve comparison of protein family interfaces, to facilitate rational ligand design, and to guide protein docking. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Real‐SPINE: An integrated system of neural networks for real‐value prediction of protein structural properties
Authors: Dor Ofer , Zhou Yaoqi 
Published: March 2007

AbstractProteins can move freely in three‐dimensional space. As a result, their structural properties, such as solvent accessible surface area, backbone dihedral angles, and atomic distances, are continuous variables. However, these properties are often arbitrarily divided into a few classes to facilitate prediction by statistical learning techniques. In this work, we establish an integrated system of neural networks (called Real‐SPINE) for real‐value prediction and apply the method to predict residue‐solvent accessibility and backbone ψ dihedral angles of proteins based on information derived from sequences only. Real‐SPINE is trained with a large data set of 2640 protein chains, sequence profiles generated from multiple sequence alignment, representative amino‐acid properties, a slow learning rate, overfitting protection, and predicted secondary structures. The method optimizes more than 200,000 weights and yields a 10‐fold cross‐validated Pearson's correlation coefficient (PCC) of 0.74 between predicted and actual solvent accessible surface areas and 0.62 between predicted and actual ψ angles. In particular, 90% of 2640 proteins have a PCC value greater than 0.6 between predicted and actual solvent‐accessible surface areas. The results of Real‐SPINE can be compared with the best reported correlation coefficients of 0.64–0.67 for solvent‐accessible surface areas and 0.47 for ψ angles. The real‐SPINE server, executable programs, and datasets are freely available on http://sparks.informatics.iupui.edu. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Creating Ultrathin Nanoscopic Collagen Matrices For Biological And Biotechnological Applications
Authors: Cisneros David A. , Friedrichs Jens , Taubenberger Anna , Franz Clemens M. , Muller Daniel J. 
Published: March 2007

AbstractThe biofunctionalization of materials creates interfaces on which proteins, cells, or tissues can fulfill native or desired tasks. Here we report how to control the assembly of type I collagen into well‐defined nanoscopic matrices of different patterns. Collagen fibrils in these ultrathin (≈3 nm) matrices maintained their native structure as observed in vivo. This opens up the possibility to create programmable biofunctionalized matrices using collagen‐binding proteins or proteins fused with collagen‐binding domains. Applied to eukaryotic cells, these nanostructured matrices can direct cellular processes such as adhesion, orientation and migration.
Directional Alignment of MG63 Cells on Polymer Surfaces Containing Point Microstructures
Authors: Mills Christopher A. , Fernandez Javier G. , Martinez Elena , Funes Miriam , Engel Elisabeth , Errachid Abdelhamid , Planell Josep , Samitier Josep 
Published: March 2007

AbstractMG63 cells cultured on regular arrays of point microstructures (posts and holes) are shown to preferentially align at certain angles to the pattern of the structures, at 0°, 30°, and 45° in particular. The effect is found to be more pronounced for post rather than hole structures (although no significant difference is found for the angles the cells make to the holes or posts) and is thought to be due to the fact that the cells use the posts as anchorage points to hold themselves to the surface. It is also shown that cells preferentially align with the structures depending on the dimensions of the structures and the distance between neighboring structures. This is important when designing structured surfaces for cell–surface interaction studies for materials to be used in, for example, drug delivery or tissue engineering.
Performance of a MANET directional MAC protocol with angle‐of‐arrival estimation
Authors: Liu Kun , Hamouda Walaa , Youssef Amr 
Published: March 2007

AbstractThe use of directional antennas in mobile ad hoc networks (MANETs) has shown to offer large throughput gains relative to omnidirectional antennas. When used in ad hoc networks, directional medium‐access‐control (DMAC) protocols usually require all nodes, or part of nodes, to be aware of their exact locations. This location information is typically provided using a global positioning system (GPS). Although GPS systems are designed to be as nearly accurate as possible, there are still estimation errors that can cause a relatively large deviation from the actual GPS receiver position. In this paper, we investigate the effect of inaccurate node position estimation on the throughput of these protocols. Our results clearly indicate that the advantages of DMAC protocols diminish if the available position information is not accurate enough. As an alternative, we propose an efficient DMAC protocol that utilizes signal parameter estimation via the rotational invariance technique (ESPRIT) for direction‐of‐arrival (DOA) estimation; alleviating the need for GPS and, hence, avoiding the degrading associated with typical GPS position estimation errors. Moreover, unlike GPS‐based protocols, our protocol is suitable for both outdoor and indoor applications. Under different operating conditions and channel models, our simulation results show the throughput improvement achieved using the proposed protocol relative to the IEEE 802.11. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of deodorization on the stability of vegetable oils
Authors: Baldwin A. Richard 
Published: March 2007

SummaryCorn oil, soybean oil, and grain sorghum oil have been deodorized in a laboratory unit equipped with a take‐off for removal of samples at various times during deodorization. Stabilities of the oils increase rapidly during the initial part of the deodorization and this increase is caused apparently by heat destruction of pro‐oxidants such as peroxides rather than by removal of volatile materials through steam distillation. These laboratory results were confirmed by a similar study of commercial deodorization of alkali‐refined and winterized corn oil.
The transesterification and chromatographic treatment of fish liver oils as a means of concentrating vitamin A
Authors: Karnovsky M. L. , Rapson W. S. , Van Rensburg N. J. 
Published: March 2007

SummaryFish liver oils containing vitamin A esters have been catalytically transesterified with ethyl alcohol, and the proportions of vitamin A alcohol produced under various conditions have been evaluated chromatographically.
The oxidation of methyl oleate. II. A reaction between methyl hydroperoxido oleate and oleic acid
Authors: Swift C. E. , Dollear F. G. 
Published: March 2007

AbstractOleic acid is intermolecularly oxidized by methyl hydroperoxido leate at 90°C, through the addition of oxygen at the olefinic bond with the formation of opexy and dihydroxy compounds. Only the lowmelting isomeric form of dihydroxystearic acid could be isolated from the reaction mixture. The oxidation of olefinic linkages by hydroperoxides appears to account, at least in part, for the observed reduction of unsaturation in autoxidizing fats.
A technique for testing the reversion properties of hydrogenated soybean oil shortenings
Authors: Handschumaker E. 
Published: March 2007

SummaryA technique has been described which was found to yield specific and reproducible evaluations of the reversion properties of shortening samples containing hydrogenated soybean oil. It was shown to be advantagenous to conduct the test by smelling rather than by tasting. The use of a control rendered the test specific and by expanding to a series of controls of varying concentrations, it was found possible to increase the discrimination of the test. The statistical method reported by Dr. Bliss (3) was used to analyze the data obtained.
The flavor problem of soybean oil. III. A four‐sample, glass laboratory deodorizer
Authors: Schwab Arthur W. , Dutton Herbert J. 
Published: March 2007

SummaryA glass laboratory deodorizer has been described which permits the simultaneous deodorization of four samples under nearly identical conditions of time, temperature, pressure and rate of steam flow. The design includes provision for measuring and controlling the steam flow, for preventing bumping, for “breaking” the vacuum, and for heating and cooling the deodorizer. Successful deodorizations have been made in relatively short periods of time. Upon deodorization of the same alkali‐refined bleached oil in each of the four flasks no difference has been found either in the initial quality or in the stability of the samples.