bluuebunny/crossref_metadata_2025 huggingface dataset:
Displacement/pressure mixed interpolation in the method of finite spheres
Authors: De Suvranu , Bathe Klaus‐Jürgen
Published: August 2002

The displacement‐based formulation of the method of finite spheres is observed to exhibit volumetric ‘locking’ when incompressible or nearly incompressible deformations are encountered. In this paper, we present a displacement/pressure mixed formulation as a solution to this problem. We analyse the stability and optimality of the formulation for several discretization schemes using numerical inf–sup tests. Issues concerning computational efficiency are also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
A finite element formulation for the simulation of propagating delaminations in layered composite structures
Authors: Wagner W. , Gruttmann F. , Sprenger W.
Published: August 2002

This paper presents a finite element method to simulate growing delaminations in composite structures. The delamination process, using an inelastic material law with softening, takes place within an interface layer having a small, but non‐vanishing thickness. A stress criterion is used to detect the critical points. To prevent mesh‐dependent solutions a regularization technique is applied. The artificial viscosity leads to corresponding stiffness matrices which guarantee stable equilibrium iterations. The essential material parameter which describes the delamination process is the critical energy release rate. The finite element calculations document the robustness and effectivity of the developed model. Extensive parameter studies are performed to show the influence of the introduced geometrical and material quantities. Copyright © 2001 John Wiley & Sons, Ltd.
The application of 3D‐microprofilometry as a tool in the surface diagnosis of fossil and sub‐fossil vertebrate hard tissue. An example from the Pliocene Upper Laetolil Beds, Tanzania
Authors: Kaiser Thomas M. , Katterwe Horst
Published: August 2002

Non‐contact optical 3D‐profiling instruments are often used in the study of surface modifications on fossil mammalian bone. The advantage of optical laser scanning for the study of fossil and sub‐fossil bone is its non‐contact nature, allowing the investigation of fragile and poorly preserved surfaces. The high resolution and fast measuring rate of this method make it an alternative to scanning electron microscopy (SEM) investigation if topography is to be visualized. This study analyses clusters of incisions in a suid humeral fragment from the Pliocene Upper Laetolil Beds. The marks show a characteristic crest structure that is also frequently found in mandible marks produced by the Australian termite species Mastotermes darwiniensis. The marks from the Laetolil Beds are, therefore, interpreted as also being caused by insect mandible action. An as yet unknown large insect species capable of modifying bone with their mandibles is thus postulated in the palaeohabitat represented by the hominid‐bearing Upper Laetolil Beds. Copyright © 2001 John Wiley & Sons, Ltd.
Prehistoric marine mammal hunting in context: two western North American examples
Authors: Colten Roger H.
Published: August 2002

The analysis of a particular type of fauna, such as marine mammals, is best understood when all categories of fauna represented are studied. Detailed analysis of a portion of an assemblage, while interesting, can contribute to misleading interpretations of prehistoric human behaviour. Faunal assemblages from coastal shell middens in southern California and Oregon provide examples of the analysis of marine mammals and their relative importance in prehistoric subsistence, economy, and culture change. While marine mammals were important for subsistence and comprise a high proportion of the bones identifiable to the species level in these assemblages, these animals were less important than fish and shellfish in the diet and probably played a limited role in culture change in these regions. Previous studies that suggest a central role for marine mammals in cultural evolution in western North America provide minimal information on other fauna, and use limited analytical methods. Quantification methods that require species level identification (such as minimum number of individuals [MNI]) can exclude much of the faunal data available from dense coastal middens, and may over emphasize some portions of the assemblage, notably large mammals. Analysis at taxonomic levels higher than species and use of several quantification techniques, including meat weight estimates, may help alleviate some of these methodological problems and lead to a better understanding of the role of marine mammals in prehistoric economies. Copyright © 2002 John Wiley & Sons, Ltd.
Preparation of the porous chitosan ­membrane by cryogenic induced phase separation
Authors: Gu Z. Y. , Xue P. H. , Li W. J.
Published: August 2002

The chitosan porous membrane was prepared by extending the principle of thermally induced phase separation (TIPS) for the polymer‐diluent system to the polymer solution at ambient temperature to carry out the cryogenic induced phase separation (CIPS). The porous membrane obtained was characterized by scanning electron microscopy (SEM) and gas permeability. It was found that a specific lacy pore structure morphology corresponding to the TIPS solid–liquid phase separation was formed in the demixing process and the porosity could be more than 70%. The research of demixing mechanism and membrane‐formation process showed that the membrane was stacked through porous lamella. The porosity of the membrane increases and the pore diameter decreases with increasing solidifying temperature. Both the porosity and pore diameter decrease with the chitosan concentration increase. Copyright © 2001 John Wiley & Sons, Ltd.
A model of pulmonary adenocarcinoma in transgenic mice expressing the simian virus 40 T antigen driven by the rat Calbindin‐D9K (CaBP9K) promoter
Authors: Chailley‐Heu Bernadette , Rambaud Caroline , Barlier‐Mur Anne‐Marie , Galateau‐Salle Françoise , Perret Christine , Capron Frédérique , Lacaze‐Masmonteil Thierry
Published: August 2002

Lung cancer is the most frequent cause of cancer deaths. Its origin and development remain poorly understood, partly because of the lack of pertinent animal models. This study produced transgenic mice expressing the simian virus (SV) 40 T antigen (Tag) driven by a 1011 base‐pair DNA fragment of the rat Calbindin‐D9K (CaBP9K) promoter. All transgenic animals developed multifocal pulmonary tumours with pathological and ultrastructural features consistent with adenocarcinomas. Using immunohistochemistry, northern blot or western blot, tumours were found to express the transcription factor TTF‐1, as well as specific markers of the peripheral airway Clara cells (CC10) and alveolar type II cells (surfactant proteins A, B, C, and D). This model, with its similarities to human adenocarcinoma, should be useful not only for addressing the mechanisms underlying the development and progression of lung cancer, but also for testing new therapeutic approaches. Copyright © 2001 John Wiley & Sons, Ltd.
β‐Glucosidase and peroxidase stability in crude enzyme extracts from green beans of Vanilla planifolia Andrews
Authors: Dignum Mark J. W. , Kerler Josef , Verpoorte Rob
Published: August 2002

The extraction method for β‐glucosidase from green vanilla beans has been studied. The effect of storage of green beans and protein extracts on β‐glucosidase and peroxidase activity was investigated: the best method, resulting in the highest enzyme activities, particularly for glucosidase, was through extraction of very fresh green beans in the presence of BisTris propane buffer at pH 8. The best method for storage of the extracts was at −80°C after addition of 15% glycerol, when over 90% of initial activity was still present. Peroxidase activity did not change in frozen beans or in frozen extracts. Copyright © 2001 John Wiley & Sons, Ltd.
Efficient method for determining the glycyrrhizin content of fresh and dried roots, and root extracts, of Glycyrrhiza species
Authors: Lauren Denis R. , Jensen Dwayne J. , Douglas James A. , Follett John M.
Published: August 2002

A reliable and efficient method suitable for the selective analysis of the glycyrrhizin content of fresh and dried roots of Glycyrrhiza species and of root extracts is described. The method was optimised for recovery and analysis of glycyrrhizin after conversion to its aglycone, 18β‐glycyrrhetinic acid. The reversed‐phase HPLC system was developed using a sterically protected C8 column that allowed UV detection of the aglycone at 254 mm without interference from co‐occurring components. The average recovery through the method was determined at 83%, with a range of 65–99%. Analysis of 150 dried root samples gave levels of glycyrrhizin consistent with earlier reported values. A comparison of post‐harvest treatment conditions showed that the drying of root samples at up to 65°C did not result in any measurable reduction in glycyrrhizin. Copyright © 2001 John Wiley & Sons, Ltd.
New 3‐deoxyanthocyanidins from leaves of Arrabidaea chica
Authors: Devia Beatriz , Llabres Gabriel , Wouters Jan , Dupont Leon , Escribano‐Bailon Maria Teresa , Pascual‐Teresa Sonia de , Angenot Luc , Tits Monique
Published: August 2002

Two new 3‐deoxyanthocyanidins, 6,7,3′,4′‐tetrahydroxy‐5‐methoxyflavylium and 6,7,4′‐trihydroxy‐5‐methoxyflavylium, and the pigment carajurin, which has been previously identified, were isolated from dried leaves of Arrabidaea chica, a creeper native to the American tropics. The structures of the components were elucidated by 1H‐ and 13C‐NMR spectroscopy and HPLC‐MS, including X‐ray crystallographic analysis for carajurin. Copyright © 2002 John Wiley & Sons, Ltd.
Increased fetal nuchal translucency at 11–14 weeks
Authors: Nicolaides Kypros H. , Heath Victoria , Cicero Simona
Published: August 2002

Nuchal translucency (NT) is the sonographic appearance of a subcutaneous collection of fluid behind the fetal neck. The measurement of fetal NT thickness at the 11–14‐week scan has been combined with maternal age to provide an effective method of screening for trisomy 21; for an invasive testing rate of 5%, about 75% of trisomic pregnancies can be identified. When maternal serum free‐β human chorionic gonadotrophin (β‐hCG) and pregnancy‐associated plasma protein‐A (PAPP‐A) at 11–14 weeks are also taken into account, the detection rate of chromosomal defects is about 90%. Increased NT can also identify a high proportion of other chromosomal abnormalities and is associated with major defects of the heart and great arteries, and a wide range of skeletal dysplasias and genetic syndromes. In monochorionic twins, discordancy for increased NT is an early marker of twin‐to‐twin transfusion syndrome (TTTS). As with the introduction of any new technology into routine clinical practice, it is essential that those undertaking the 11–14‐week scan are adequately trained and their results are subjected to rigorous audit. Copyright © 2002 John Wiley & Sons, Ltd.
Cadmium recovery and recycling from chemical bath deposition of CdS thin layers
Authors: Malinowska B. , Rakib M. , Durand G.
Published: August 2002

Cadmium sulfide thin layers for polycrystalline solar cells are produced by chemical bath deposition (CBD). This process generates wastes containing mainly ammonia and cadmium. We have implemented and described in a previous paper a process to recover 90% of ammonia and to confine cadmium as a cake which is a mixture of cadmium sulfide and cadmium cyanamide. The present paper concerns cadmium recycling to the CBD step. The cake is first dissolved in a moderate sulfuric acid solution 0.2–0.5 mol/l mixed with hydrogen peroxide (about 1 mol/l). This last component must be used in large excess (molar ratio H2O2/Cd ≥ 5) and must be completely removed from the solution before recycling or cadmium electrowinning. Hydrogen peroxide decomposition is electrochemically catalyzed by platinized platinum immersed into the solution. The resulting solution contains cadmium sulfate 0.2 mol/l, sodium and ammonium sulfate. One can either recycle it as a chemical bath, or recover the cadmium content by electrowinning; in this case the residual concentration of hydrogen peroxide is electrochemically reduced at the beginning of cadmium electrolysis. The raffinate solution is recycled into the stripping reactor. The pure cadmium metal recovered may be dissolved in a dilute sulfuric acid solution by means of internal electrolysis with two electrodes: a platinized platinum grid as cathode and the cadmium metal as anode. According to the mass of cadmium dissolved it is possible to obtain a concentrated solution of pure cadmium sulfate. The global process recovers at least 99.999% of cadmium and generates only solid sulfur and a liquid effluent containing traces of cadmium (< 10 μg/l). Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and miscibility studies of [60]fullerenated poly(2‐hydroxyethyl methacrylate)
Authors: Goh H. W. , Goh S. H. , Xu G. Q.
Published: August 2002

[60]Fullerenated poly(2‐hydroxyethyl methacrylate)s containing 0.6–3.0 wt % C60 were synthesized. These polymers are soluble in methanol and N,N‐dimethylformamide (DMF). [60]Fullerenated poly(2‐hydroxyethyl methacrylate)s with higher C60 contents are only sparingly soluble in DMF and virtually insoluble in other organic solvents. A loading of 1.2 wt % C60 in poly(2‐hydroxyethyl methacrylate) does not greatly affect its miscibility with poly(N‐vinyl‐2‐pyrrolidone), poly(1‐vinylimidazole), and poly(4‐vinylpyridine). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1157–1166, 2002
Helical chirality of π‐conjugated main‐chain induced by polymerization of phenylacetylene with chiral bulky pinanyl groups: Effects of the flexible spacer and polymerization catalyst
Authors: Shinohara Ken‐ichi , Aoki Toshiki , Kaneko Takashi
Published: August 2002

Three optically active phenylacetylene polymers with chiral bulky pinanyl groups, (−)‐poly[4‐(dimethylpinanylsilyl)phenylacetylene] [(−)‐poly(PSPA)], (+)‐poly{4‐[3‐(10‐pinanyl)tetramethyldisiloxy]phenylacethylene} [(+)‐poly(PDSPA)], and their copolymer [(−)‐copoly(PSPA/PDSPA)], were synthesized. We observed high chirality in the main‐chain chromophore of (−)‐poly(PSPA), due to the presence of a chiral helix, with circular dichroism spectroscopy. In contrast, (+)‐poly(PDSPA),with flexible SiOSi spacers between the chiral pinanyl group and the main chain, had lower chirality. (−)‐Poly(PSPA), with large circular dichroism signals, was prepared by polymerization with a rhodium catalyst and had a highly stereoregular main chain (high cis‐configuration percentage). However, (−)‐poly(PSPA) prepared with a tungsten catalyst had lower chirality and lower stereoregularity in the main chain. A membrane from (−)‐poly(PSPA) showed enantioselective permeability for tryptophan in an aqueous solution. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1689–1697, 2002
Controlled radical polymerization of 2‐hydroxyethyl methacrylate with a hydrophilic ruthenium complex and the synthesis of amphiphilic random and block copolymers with methyl methacrylate
Authors: Fuji Yusuke , Watanabe Kazuya , Baek Kyung‐Youl , Ando Tsuyoshi , Kamigaito Masami , Sawamoto Mitsuo
Published: August 2002

A hydrophilic ruthenium complex with ionic phosphine ligands {1: RuCl2[P(3‐C6H4SO3Na)(C6H5)2]2} induced controlled radical polymerization of 2‐hydroxyethyl methacrylate (HEMA) in methanol under homogeneous conditions; the initiator was a chloride (R‐Cl) such as CHCl2COPh. The number‐average molecular weights of poly(HEMA) increased in direct proportion to monomer conversion, and the molecular weight distributions were relatively narrow (Mw/Mn = 1.4–1.7). A similar living radical polymerization was possible with (MMA)2‐Cl [(CH3)2C(CO2CH3)CH2C(CH3)(CO2CH3)Cl] as an initiator coupled with amine additives such as n‐Bu3N. In a similar homogeneous system in methanol, methyl methacrylate (MMA) could also be polymerized in living fashion with the R‐Cl/1 initiating system. Especially for such hydrophobic polymers, the water‐soluble ruthenium catalyst was readily removed from the polymers by simple washing with an aqueous dilute acid. This system can be applied to the direct synthesis of amphiphilic random and block copolymers of HEMA and MMA. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2055–2065, 2002
Hollow‐particle latexes: Preparation and properties
Authors: Pavlyuchenko V. N. , Sorochinskaya O. V. , Ivanchev S. S. , Klubin V. V. , Kreichman G. S. , Budtov V. P. , Skrifvars M. , Halme E. , Koskinen J.
Published: August 2002

Hollow‐particle latexes were prepared according to the following stages: (1) the preparation of the methyl methacrylate–methacrylic acid (MAA)–ethylene glycol dimethacrylate copolymer (I) latex, (2) the preparation of a shell (II) based on polystyrene or styrene–acrylonitrile–divinyl benzene copolymer polymerized onto copolymer (I) particles, and (3) the neutralization of the core (I) carboxyl groups with a base (NH4OH or NaOH) at temperatures close to the glass‐transition temperature of the polymer (II). The neutralization resulted in the expansion of the particles and formed water‐filled hollow particles. The microspheres had an overall diameter of 460–650 nm and a hollow diameter of 300–450 nm. Rheological studies and particle size measurements by transmission electron microscopy and dynamic light scattering of the copolymer (I) latex indicate that the maximum particle swelling occurred at an approximately equimolar MAA/base ratio. It was found that even without the neutralization of the MAA units, a small hollow formation in the latex particles occurred during stage 2 because one volume of the copolymer (I) retained about 8 volume parts of water. It was also discovered that the final hollow‐particle geometry after neutralization depends on the shell copolymer thickness and type as well as on the conditions during stage 3, that is, the time, temperature, base type, and concentration. The opacifying ability of the synthesized hollow particles was investigated in latex coatings. The opacifying ability values were generally in agreement with the hollow‐particle geometry. The only exception was related to the copolymer (I)/copolymer (II) ratio. The maximum hollow volume was obtained at this value equal to 1/8, whereas the highest opacifying ability was observed at 1/10. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1435–1449, 2001
Regioselective and stereoselective alternating copolymerization of carbon monoxide with functional olefins
Authors: Yuan Jian Chao , Chen Min Dong , Zhang Yu Hua , Lu Shi Jie
Published: August 2002

Enantioselective, alternating copolymerizations of carbon monoxide with ω‐undecylenic acid, ethyl acrylate, and butyl acrylate were carried out for the first time with a palladium catalyst modified by 1,4:3,6‐dianhydro‐2,5‐dideoxy‐2,5‐bis(diphenylphosphino)‐L‐iditol. Optical rotation, elemental analysis, and 1H NMR,13C NMR, and IR spectra showed that the copolymers were optically active, isotactic, alternating poly(1,4‐ketone) or poly(spiroketal) structures. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2027–2036, 2001
Synthesis of high molar mass poly(alkylene phosphate)s by polyaddition of diepoxides to difunctional phosphoric acids: Unusual elimination of the side reactions
Authors: Biedron T. , Kaluzynski K. , Pretula J. , Kubisa P. , Penczek S. , Loontjens T.
Published: August 2002

The reaction between diepoxides and difunctional acids of phosphorus was studied as a potential route to linear polyesters of phosphoric acid. The reaction between diepoxide and POH groups in H3PO4 and related acids leads to linear phosphates, but cyclic phosphates are also formed as side products. The formation of such unreactive groups terminates polyaddition. However, cyclization is practically eliminated when the epoxide ring is fused to another ring, such as in cyclohexene oxide. A commercially available diepoxide containing two cyclohexene oxide moieties, 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexanecarboxylate (ERL), was, therefore, used for polyaddition studies. Indeed, in the polyaddition of ERL with ethylphosphoric acid, high molecular weight (number‐average molecular weight up to 104) linear polyphosphates were obtained. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3024–3033, 2001
Early cure behavior of a liquid dicyanate ester resin
Authors: Lin King‐Fu , Shyu Jing‐Yau
Published: August 2002

The early cure behavior of 4,4‐dicyanato 1,1‐diphenolethane resin with and without incorporating Cr(acac)3, Co(acac)3, and Cu(acac)2, respectively, as catalysts was investigated by gel permeation chromatography. The curing intermediates were separated by the column elution method and characterized by Fourier transform infrared, 1H, and 3C NMR spectroscopies. The results indicated that the formed dimer in the early cure stage is a straight chain containing a primary amino group. The formed triazine ring in the trimer has a strong catalytic effect on the remaining cyanate groups so that the reactivity of the trimers was significantly increased. The reactivities of the curing intermediates decreased with molecular size until 7‐mer was reached. The initial monomer consumption is described by second‐order‐rate kinetics. In the presence of metal acetylacetonates, the curing reactions may be accelerated, but they did not change the reaction path and preceding sequence of reactivities. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3085–3092, 2001
Morphology of micron‐sized, monomer‐adsorbed, crosslinked polymer particles having snowmanlike shapes prepared by the dynamic swelling method
Authors: Okubo Masayoshi , Wang Zhaoqun , Yamashita Tsuyoshi , Ise Eriko , Minami Hideto
Published: August 2002

A series of monomer‐adsorbed, crosslinked polystyrene/polydivinylbenzene composite particles having snowmanlike shapes were prepared by the dynamic swelling method that the authors had proposed in 1991. The morphology of the snowman‐shaped particles was estimated with the contact angle of the monomer phase on the polymer particle. Influences of the kind of monomers and polyvinyl alcohol colloidal stabilizer on the morphology were obviously observed and discussed from the viewpoint of thermodynamic stability. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3106–3111, 2001
Hydrogen‐bonding interaction and miscibility between poly(ε‐caprolactone) and enzymatically polymerized novel polyphenols
Authors: He Yong , Li Jianchun , Uyama Hiroshi , Kobayashi Shiro , Inoue Yoshio
Published: August 2002

The intermolecular hydrogen‐bonding interaction and miscibility between enzymatically prepared novel polyphenols [poly(bisphenol A) and poly(p‐tert‐butyl phenol)] and poly(ε‐caprolactone) (PCL) were investigated as a function of composition by Fourier transform infrared spectroscopy (FTIR) and DSC. The blend films of PCL and polyphenols were prepared by casting polymer solution. The FTIR spectra clearly indicated that PCL and polyphenols interact through strong intermolecular hydrogen bonds formed between the PCL carbonyls and the polyphenol hydroxyl groups. The melting point and degree of crystallinity of the PCL component decreased with an increased polyphenol content. A single glass‐transition temperature was observed for the blend, and its value increased with the content of polyphenol, indicating that PCL and polyphenols are miscible in the amorphous state. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2898–2905, 2001
Crystallization kinetics and melting behavior of metallocene short‐chain branched polyethylene fractions
Authors: Chiu Fang‐Chyou , Fu Qiang , Peng Ya , Shih Hsi‐Hsin
Published: August 2002

Metallocene polyethylene (mPE) fractions are recognized as being more homogeneous with respect to short‐chain branch (SCB) distribution as compared with unfractionated mPEs. Differential scanning calorimetry and polarized optical microscopy (POM) were used to study the influences of SCB content on the crystallization kinetics, melting behavior, and crystal morphology of four butyl‐branched mPE fractions. The parent mPE of the studied fractions was also investigated for comparative purposes. mPE fractions showed a much simpler crystallization behavior as compared with their parent mPE during the cooling experiments. The Ozawa equation was successfully used to analyze the nonisothermal crystallization kinetics of the fractions. The Ozawa exponent n decreased from about 3.5 to 2 as the temperature declined for each fraction, indicating the crystal‐growth geometry changed from three‐dimensional to two‐dimensional. For isothermal crystallization, the fraction with a lesser SCB content exhibited a higher crystallization temperature (Tc) window. The results from the Avrami equation analysis showed the exponent n values were around 3 (with minor variation), which implied that the crystal‐growth geometry is pseudo‐three‐dimensional. Both of the activation energies for nonisothermal and isothermal crystallization were determined for each fraction with Kissinger and Arrhenius‐type equations, respectively. Double melting peaks were observed for both nonisothermally or isothermally crystallized specimens. The high‐melting peak was confirmed induced via the annealing effect during heating scans. The Hoffman–Weeks plot was inapplicable in obtaining the equilibrium melting temperature (Tm°) for each fraction. The relationship between Tc and Tm for the fractions is approximately Tm = Tc (°C) + 8.3. The POM results indicated that the crystals of parent or fractions formed under cooling conditions did not exhibit the typical spherulitic morphology as a result of the high SCB content. © 2002 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 325–337, 2002
Exchange equilibria on nonconventional pyridine strong base anion exchangers by surface‐complexation theory
Authors: Neagu Violeta , Luca Cornelia
Published: August 2002

The surface‐complexation theory was applied for the description of ion‐exchange equilibria on nonconventional strong base anion exchangers with pyridine structures. Binary equilibria are described by a logarithm equilibrium parameter that is a linear function of the composition of the resin phase for chloride/nitrate, chloride/bicarbonate, and chloride/sulfate ion exchanges. Evaluation of date demonstrates that there are similar predictions from ion‐exchange isotherms and the surface‐complexation theory for the studied ion exchanges. We assume that ion‐exchange equilibrium, regardless of its approach model, depends on the relationship between the chemical structure of the functional sites of the ion exchanger and the counterions that partake to the ion‐exchange process. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 488–494, 2002; DOI 10.1002/polb.10097
Friction and damage in the scratching of poly(n‐butyl acrylate) films
Authors: Zhang S. L. , Tsou A. H. , Li J. C. M.
Published: August 2002

Scratch testing was performed on poly(n‐butyl acrylate) (PnBA) films with a sapphire indenter with a spherical tip (76 μm in radius). For uncrosslinked PnBA film, the surface of which is sticky, the horizontal or scratching force decreases with decreasing normal load and has a residual value (∼ 6 mN) as the normal load approaches zero. The relation between the scratching force and normal load can be understood by finite element computation based on the Johnson–Kendall–Roberts theory under the assumption that the scratching force is proportional to the contact area, which depends on the normal load. With increasing driving speed, the scratching force shows a power relation with speed indicating a rate process. For crosslinked PnBA film, which behaves as an elastomer, the horizontal force approaches zero at zero normal load. Below a critical normal load, which depends on the thickness of the film, the crosslinked film recovers elastically after being scratched. Above the critical load, the film is damaged and, depending on its thickness, shows two distinct damage mechanisms. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 585–592, 2002; DOI 10.1002/polb.10117
Modeling of tensile moduli in polystyrene/ polybutadiene blends
Authors: Joseph Susan , Thomas Sabu
Published: August 2002

The tensile moduli of polystyrene/polybutadiene blends were studied with reference to the effect of the blend ratio. A comparison between the experimental results and the theoretical predictions of the tensile properties was also made. The models selected were the parallel, series, Halpin–Tsai, Takayanagi, Kerner, and Kunori models. Various theoretical models were applied to predict the location of the phase inversion region in these blends. Different equations were also applied for the prediction of the tensile modulus of cocontinuous structures for comparison. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 755–764, 2002
Solid‐state NMR analyses of the crystalline–noncrystalline structure and its thermal changes for ethylene ionomers
Authors: Kuwabara Kazuhiro , Horii Fumitaka
Published: August 2002

The crystalline–noncrystalline structure and its structural changes from thermal treatments for ethylene ionomers have been investigated with solid‐state 13C and 23Na NMR spectroscopy. 13C spin–lattice relaxation time (T1C) measurements reveal that as‐received ethylene ionomers have much enhanced molecular mobility in the crystalline region in comparison with conventional polyethylene samples. By appropriate annealing, however, polyethylene‐like morphological features reflecting T1C behavior can also be observed. 13C spin–spin relaxation time (T2C) measurements for the noncrystalline region reveal the existence of two components with different T2C values, and these two components have been assigned to the crystalline–amorphous interfacial and rubbery–amorphous components. These results indicate that the structure of the major part of the noncrystalline region in the ethylene ionomers is similar to that of bulk‐crystallized polyethylene samples, regardless of possible ionic aggregates. The origin of the lower temperature endothermic peak in the heating process of the differential scanning calorimetry curve observed for the as‐received sample has also been examined somewhat in detail. As a result, it is proposed that the melting of smaller crystallites produced during storage at room temperature is the origin of the lower temperature peak. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1142–1153, 2002
Deterioration of a polyurethane coating studied by positron annihilation spectroscopy: Correlation with surface properties
Authors: Wu Y. C. , Huang Chia‐Ming , Li Y. , Zhang R. , Chen H. , Mallon P. E. , Zhang J. , Sandreczki T. C. , Zhu Da‐Ming , Jean Y. C. , Suzuki R. , Ohdaira T.
Published: August 2002

Deterioration of a polyurethane coating by Florida natural environments as a function of time up to 16 weeks was studied by positron annihilation spectroscopy. Doppler broadening energy spectroscopy (DBES) of annihilation irradiation and positron annihilation lifetime (PAL) were measured as a function of incident positron energy (0–30 keV). A significant decrease in the S‐defect parameter from DBES and the intensity of orthopositronium from PAL was observed as a function of weathering time. This is interpreted as a loss of free volume and holes as a result of the weathering process. The gloss and surface morphology in the same system were measured by glossimetry and atomic force microscopy (AFM), respectively. The gloss decreased and surface roughness increased as a function of weathering time. The AFM images showed a new feature of a spherically coagulated microstructure on the surface after weathering. Direct correlations between the decrease in gloss and the increase in roughness as well as the decrease in the S‐defect parameter from the DBES data and in the free volume from the PAL data were observed. These results were used to discuss the weathering process in terms of chemical and physical changes as a result of photodegradation in protective polymeric systems. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2290–2301, 2001
Physical modelling of bedrock brecciation by ice segregation in permafrost
Authors: Murton J. B. , Coutard J.‐P. , Lautridou J.‐P. , Ozouf J.‐C. , Robinson D. A. , Williams R. B. G.
Published: August 2002

The lower half of a large block of moist chalk was maintained at subzero temperatures while the upper half was cyclically frozen and thawed, simulating 19 seasonal temperature cycles in an active layer above permafrost. During the experiment, the rock surface heaved vertically by at least 34.7 mm. Sixty‐one percent of the heave occurred during freezing periods, and is attributed primarily to ice segregation accompanying upward freezing from the permafrost table during the early stages of simulated winters. Thirty‐nine percent of the heave occurred during thawing periods, and is attributed to ice segregation in the frozen rock beneath the thaw front during the mid to late stages of simulated summers. By the end of the experiment, the middle horizon of the chalk, representing the upper part of the simulated permafrost and the basal part of the active layer, had become strongly brecciated and rich in segregated ice. The style of brecciation has similarities with that in perennially‐frozen limestone, sandstone and shale in Svalbard and Canada, and chalk frozen during Quaternary cold stages in France and England. These similarities suggest that ice segregation during perennial and seasonal freezing is an important process of weathering and coarse‐sediment supply in areas of frost‐susceptible bedrock. Copyright © 2001 John Wiley & Sons, Ltd.
Exhaled nitric oxide concentrations: Online versus offline values in healthy children
Authors: Kissoon Niranjan , Duckworth Laurie J. , Blake Kathryn V. , Murphy Suzanne P. , Taylor Christopher L. , DeNicola Lindsay R. , Silkoff Philip E.
Published: August 2002

Exhaled nitric oxide (FENO) is a noninvasive and practical method to assess airway inflammation. We conducted this investigation to determine the most appropriate flow rate to measure FENO and to obtain reference values for FENO in children. FENO was measured in 112 healthy 6–18 year olds (60 males) at 4 expiratory flow rates (46, 31, 23, and 15 mL/sec) using a chemiluminescent nitric oxide analyzer. Offline and online analyses were done to determine FENO intraclass correlation coefficients, the relationship between FENO and expiratory flow rates, and the effects of age and gender on these measurements.

The major findings were: 1) intraclass correlation coefficients for FENO and flow rates ranged from 0.92–0.99 for offline values, and 0.99 for all online values; 2) variation at an expiratory flow rate of 46 mL/sec (SD, 9.39) was considerably less than at other flows, especially at 15 mL/sec (SD, 26.55); 3) FENO increased as flow rates decreased for both offline and online values; 4) there were no significant differences and good agreement between offline bag and online FENO values at 31 and 46 mL/sec expiratory flows; and 5) using multiple regression, significant predictors of FENO were flow, body surface area, age, and FEF25–75.

We have provided FENO values in healthy children and propose that the ideal expiratory flow rate for FENO measurements in children using the single breath technique is between 30–50 mL/sec. Pediatr Pulmonol. 2002; 33:283‐292. © 2002 Wiley‐Liss, Inc.
Baicalin is a major component of PC‐SPES which inhibits the proliferation of human cancer cells via apoptosis and cell cycle arrest
Authors: Ikezoe Takayuki , Chen Sophie S. , Heber David , Taguchi Hirokuni , Koeffler H. Phillip
Published: August 2002

Background

PC‐SPES is an eight‐herb mixture that was shown to have activity against prostate cancer. Recently, we isolated a major component (6% of the total ethanolic extract) known as baicalin from PC‐SPES by high performance liquid chromatography (HPLC).

Methods

Baicalin was evaluated for its ability to inhibit clonal growth, and to induce cell cycle arrest of various cancer types (PC‐3, DU145, LNCaP prostate cancer cell lines, MCF‐7 breast cancer cell line, HL‐60 myeloblastic leukemia cell line, and NB4 promyelocytic leukemia cell line). The ability of baicalin to induce apoptosis of cancer cells was examined by both staining with Annexin V and detection of cleavage of Poly (ADP‐ribose) polymerase (PARP)3. Western blot analysis examined the effect of baicalin on levels of p21waf1 and p27kip1 in those cells. Futhermore, induction of differentiation in HL‐60 cells was measured by expression of CD11b.

Results

Baicalin inhibited the clonal proliferation of LNCaP and PC3 prostate cancer cell lines, and the HL‐60 and NB4 myeloblastic/promyelocytic leukemia cell lines with a 50% inhibition (ED50) that ranged between 6.4 × 10−6 to 12 × 10−6 mol/L. Cell cycle analysis showed that baicalin (2 × 10−5 mol/L, 4 days) caused a G0/G1 and G2/M accumulation of LNCaP and HL‐60 cells, respectively. Concomitantly, differentiation and apoptosis were induced in HL‐60 cells, as measured by expression of CD11b antigen, staining with annexin V, and detection of cleavage of PARP. Moreover, baicalin enhanced the expression of the cyclin‐dependent kinase inhibitor, p27kip1 in LNCaP and HL‐60 cells.

Conclusions

Baicalin inhibited the proliferation of cancer cells via apoptosis and cell cycle arrest, in which p27kip1 may play a role. Baicalin may be a novel, adjunctive therapy for selected malignancies including prostate cancer. Prostate 49:285–292, 2001. © 2001 Wiley‐Liss, Inc.
High level of α1‐acid glycoprotein in human seminal plasma is associated with high branching and expression of Lewisa groups on its glycans: Supporting evidence for a prostatic origin
Authors: Poland Dennis C.W. , Kratz Ewa , Vermeiden Jan P.W. , De Groot Steffen M. , Bruyneel Ben , De Vries Theodora , Van Dijk Willem
Published: August 2002

BACKGROUND

Changes in concentration of seminal plasma α1‐acid glycoprotein (AGP) have been studied in detail before. However, the source of high levels of AGP as well as the glycosylation of seminal plasma AGP has not been elucidated yet.

METHODS

The glycosylation of AGP was studied by crossed affinity immunoelectrophoresis using fucose‐specific lectins and immunostaining. Glycan structure and monosaccharide analyses were performed by high pH anion exchange chromatography with pulsed amperometric detection. Fucosyltransferases were analyzed for activity and their substrate specificity was determined.

RESULTS

Two types of fucosylation were detected; Lewisx and Lewisa. Lewisa groups were only present on AGP of individuals with a high concentration and were completely absent when the AGP concentration in seminal plasma was low. Lewisa expression coincides with a higher degree of branching of the glycans and a relative increased α4‐fucosyltransferase activity. The molecular weight of all seminal plasma AGP was slightly higher than of blood plasma AGP (approx. 47 vs. 41–43 kDa).

CONCLUSIONS

The results indicate that AGP in seminal fluid most likely originates from the prostate and that it is either α3‐ or α4‐fucosylated. Prostate 52: 34–42, 2002. © 2002 Wiley‐Liss, Inc.
Transrectal ultrasound for monitoring murine orthotopic prostate tumor
Authors: Kusaka Nobuyuki , Nasu Yasutomo , Arata Ryoji , Saika Takashi , Tsushima Tomoyasu , Kraaij Robert , Bangma Chris H. , Kumon Hiromi
Published: August 2002

BACKGROUND

The mouse orthotopic prostate tumor model has been recognized as an ideal preclinical animal model simulating the anatomical and biological milieu of the prostate. In comparison with the subcutaneous tumor model, the only disadvantage of this model is the difficulty of chronological tumor growth monitoring. We have applied recent endoluminal ultrasound technology, transrectal ultrasonography (TRUS), to the monitoring of mouse orthotopic prostate tumors.

METHODS

A 6 Fr. 20 MHz catheter‐based radial scan probe was used and TRUS was performed without any prior preparation including anesthesia. Orthotopic tumors were initiated by inoculation of 5000 RM‐9 cells into the dorsal prostate of 12‐week‐old C57BL/6 male mice. The tumor growth was monitored by TRUS from day 3 to day 21. In addition, TRUS was performed to detect tumor growth suppression after intraperitoneal administration of cis‐diamminedichloroplatinum (CDDP).

RESULTS

By ultrasound, tumors became detectable 7 days after tumor cell inoculation. TRUS images were clear and parallel to actual tumor growth. The tumor volume (X) calculated by TRUS correlated significantly with the actual tumor weight (Y) measured at autopsy; Y = 101.653 + 1.174X (R = 0.930, P < 0.001). Similarly, tumor growth suppression induced by CDDP was clearly detected by TRUS with reasonable accuracy.

CONCLUSIONS

A high resolution TRUS allows simple and reliable monitoring of in situ tumor growth and growth suppression, making the mouse orthotopic prostate tumor model more efficient. Prostate 47:118–124, 2001. © 2001 Wiley‐Liss, Inc.
Karyometry of secretory cell nuclei in high‐grade PIN lesions*
Authors: Bartels Peter H. , Montironi Rodolfo M. , Bostwick David , Marshall James , Thompson Deborah , Bartels Hubert G. , Kelley David
Published: August 2002

Background

The goal of this study was a karyometric characterization of secretory cell nuclei in high‐grade prostatic intraepithelial neoplasia (PIN) lesions. Specifically, the hypothesis is tested that distinctly different subgroups of nuclei exist in these lesions.

Methods

High‐resolution images of 1,713 nuclei from high‐grade PIN lesions were recorded. Karyometric features were computed. Discriminant function scores against normal reference nuclei, and nuclear abnormality values were derived. Data sets were processed by a nonsupervised learning algorithm to establish the presence of subgroups of nuclei with statistically different nuclear chromatin distributions.

Results

Three sets of nuclei were formed, facing an intact basal cell layer, a near vanishing basal cell layer, and a gap in the basal cell layer. For each set, a nonsupervised learning algorithm formed three statistically different subgroups of approximately equal sizes. Each subgroup is found in every one of the three sampling locations. The total optical density distribution of nuclei in two subgroups suggests an aneuploid distribution, the third subgroup has a near diploid distribution.

Conclusions

Secretory cell nuclei in high‐grade PIN lesions are a heterogeneous population, forming statistically different subgroups. Studies aimed at characterizing the progression of such lesions should consider the inhomogeneous nature of these nuclei. Prostate 48:144–155, 2001. © 2001 Wiley‐Liss, Inc.
High fat diet increases the weight of rat ventral prostate
Authors: Cai Xiaoyan , Haleem Riffat , Oram Shane , Cyriac Jomol , Jiang Feng , Grayhack John T. , Kozlowski James M. , Wang Zhou
Published: August 2002

BACKGROUND

Understanding the mechanisms by which diet influences the prostate may eventually lead to novel approaches for preventing prostate cancer. The objective of this research is to examine the impact of dietary fat, vitamin D, and genistein on prostate weight, serum and intraprostatic androgen levels, and the expression of several androgen‐response genes.

METHODS

Sprague–Dawley rats were fed, beginning at 21 days of age, for 1 or 3 months of experimental diets with high saturated fat (32.2% calories from fat), low saturated fat (3.6% calories from fat), genistein plus (20 mg/kg), genistein deficient, vitamin D surplus (4,000 U/kg), or vitamin D deficient. The body weight, food intake, the weights of the ventral prostate and dorsolateral prostate, and the levels of testosterone and dihydrotestosterone (DHT) in the serum and in the prostate were determined. The expression of androgen‐response genes was characterized by Northern blot analysis.

RESULTS

The pilot experiments showed that high dietary fat appeared to consistently increase the weight of the ventral prostate, while vitamin D or genistein did not have a consistent effect on prostate weight. Further analysis confirmed that the ventral prostate is 15% (P < 0.001) heavier in the rat on a high fat diet as compared to a low fat diet. Dietary fat had no significant influence on the levels of serum and intraprostatic androgens and the expression of androgen‐response genes.

CONCLUSIONS

Our results suggested that the ventral prostate weight of the rat is increased without affecting the androgen axis by feeding the animals with high fat diet beginning at 21 days of age. This observation is potentially important since epidemiological data suggest that saturated fat consumption is a major risk factor associated with prostate cancer incidence rate. Prostate 49:1–8, 2001. © 2001 Wiley‐Liss, Inc.
Comparative structural analysis of psychrophilic and meso‐ and thermophilic enzymes
Authors: Gianese Giulio , Bossa Francesco , Pascarella Stefano
Published: August 2002

Enzymes adapted to cold display structures comparable with those of their meso‐ and thermophilic homologs but are characterized by a higher catalytic efficiency at low temperatures and by thermolability at moderate temperatures. To identify the structural factors responsible of such features, we undertook a systematic comparative analysis of several structural properties in a data set consisting of 7 cold active enzymes belonging to different structural families and 28 related structures from meso/thermophiles representing most of the structural information now available. Only high‐resolution and high‐quality structures were considered. Properties were calculated and then compared for each pair of 3D structures displaying different temperatures of adaptation using a temperature‐weighting scheme. The significance of the resulting differences was evaluated with a statistical method. Results reveal that each protein family adopts different structural strategies to adapt to low temperatures. However, some common trends are observed: the number of ion pairs, the side‐chain contribution to the exposed surface, and the apolar fraction of the buried surface show a consistent decrease with decreasing optimal temperatures. Proteins 2002;47:236–249. © 2002 Wiley‐Liss, Inc.
Modifications to canonical structure sequence patterns: Analysis for L1 and L3
Authors: Vargas‐Madrazo Enrique , Paz‐García Enrique
Published: August 2002

The conformation of five of the six hypervariable loops that form the antigen‐binding site of antibodies is limited to a small set of structures designated as canonical structures. The canonical structure model has been constituted as a fundamental tool for the modeling of antibodies. The detailed study of tens of crystallographic structures of antibodies has shown the validity of this model in the great majority of cases. The robustness of the forecast capacity of this model depends fundamentally on the precision with which the sequence patterns that characterize each canonical structure form can be defined. Nevertheless, due to the enormous quantity of structural information about antibodies generated during the last decade, it is difficult to avoid mistakes or confusion in the model. In the present work, we propose some corrections to the model for loops L1 and L3 that permit defining sequence patterns that avoid confusion and make better forecasting of the canonical structure model possible. Proteins 2002;47:250–254. © 2002 Wiley‐Liss, Inc.