bluuebunny/crossref_metadata_2025 huggingface dataset:
Earthquake Risk and Hazard Mitigation in Turkey
Authors: Bakır Pelin G. , Bodurog˘lu Hasan M.
Published: October 2002

The last two earthquakes in Marmara have been catastrophic disasters beyond all limits of perception. On 17 August 1999, there were 1 million people trapped under debris, eighteen thousand people had lost their lives, and hundreds of thousands had been evacuated from their homes. Roads had buckled and bridges had fallen down. On 12 November 1999 another earthquake hit Düzce. This earthquake also caused high casualties. There were 894 deaths and 4,948 injuries. Both of the disasters had social, technical, administrative, legal, economical as well as environmental consequences. This paper presents a brief overview of these earthquakes in terms of the six aspects mentioned above. Disaster management practices are also investigated. The authors are of the opinion that it is not only the buildings but also poor disaster management before, during, and after the disaster that kill people in severe earthquakes. The present disaster management system of Turkey is compared against professional standards of the United States and Japan. The authors systematically document where performance failed and offer proposals for change within the Turkish disaster management system.
Base Isolation and Supplemental Damping Systems for Seismic Protection of Wood Structures: Literature Review
Authors: Symans Michael D. , Cofer William F. , Fridley Kenneth J.
Published: October 2002

This paper provides a literature review on the application of base isolation and supplemental damping systems for seismic protection of wood structures. The review reveals that both elastomeric bearings and sliding bearings have been considered for implementation within base isolation systems of wood-framed buildings. In addition, friction dampers, viscoelastic dampers, hysteretic dampers, and fluid viscous dampers have been considered for implementation within the framing of wood buildings. Although there are a number of impediments to the widespread implementation of such advanced seismic protection systems, the reviewed literature clearly demonstrates that advanced seismic protection systems offer promise for enabling light-framed wood structures to resist major earthquakes with minimal damage.
Coordination polymers of copper(II) with some dicarboxysiloxane ligands
Authors: Cazacu Maria , Airinei Anton , Marcu Mihai
Published: October 2002

Several new coordination polymers of copper(II) with different carboxylate ligands containing siloxane units were synthesized by equilibrium polycoordination reactions of copper(II) acetate with the proper dicarboxylic acid (i.e. 1,3‐bis(3‐carboxypropyl)tetramethyldisiloxane, α,ω‐bis(3‐carboxypropyl)oligodimethylsiloxane, and 1,3‐bis(sebacomethyl)tetramethyldisiloxane) in solution (methanol), at room temperature. Some variations in the feed molar ratios were made. The resulting polymers having a polycoordination degree between 5 and 71 are soluble in a wide range of common organic solvents. The formation of polymers was proved by IR and UV–VIS absorption spectroscopy. The thermal behaviour of the coordination polymers was analysed by thermogravimetry in air. The silicon and copper contents and inherent viscosities were also determined. Copyright © 2002 John Wiley & Sons, Ltd.
Hydroformylation – amidocarbonylation of androstene and pregnene derivatives
Authors: Nagy Emese , Benedek Csilla , Heil Bálint , Tőrös Szilárd
Published: October 2002

Androstene and pregnene derivatives were functionalized by amides with rhodium or binary rhodium–cobalt catalysts. Whereas the Rh–PPh3 catalyzed reaction results in the unsaturated amido‐methylidene derivatives, the rapid hydrogenation of these compounds takes place in the presence of a basic PR3 ligand. Using a binary rhodium–cobalt system, amidocarbonylation of the steroids occurs with high chemo‐ and regio‐selectivity. Our experiments did not support literature reports claiming the essential role of a bimetallic cluster as the active catalyst. Copyright © 2002 John Wiley & Sons, Ltd.
Study on a water‐swellable rubber compatibilized by amphiphilic block polymer based on poly(ethylene oxide) and poly(butyl acrylate)
Authors: Wang Caiqi , Zhang Guo , Dong Yuping , Chen Xingfang , Tan Huimin
Published: October 2002

A water‐swellable rubber (WSR), compatibilized by the amphiphilic block copolymer, has been prepared by blending a natural rubber (NR) matrix with crosslinked sodium polyacrylate (CSP), poly(ethylene oxide)‐b‐poly(butyl acrylate) (PEO‐b‐PBA), poly(ethylene glycol) (PEG), reinforced filler, and vulcanizing agents. The preparation process was described. The microphase structure of WSR was characterized by a scanning electron microscopy (SEM) photograph. The dependence of the degree of the water‐absorbing and the water‐swelling, the water‐absorbing and water‐swelling rates on CSP, PEG, and PEO‐b‐PBA contents were investigated. The compatibilizing mechanism of PEO‐b‐PBA on WSR was studied. And the optimum composition range was identified: CSP (30–60 phr), PEG (10–20 phr) PEO‐b‐PBA (PEO/PBA = 0.36, 5 phr). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3120–3125, 2002
Light‐scattering study on porous membrane formation by dry‐cast process
Authors: Matsuyama Hideto , Tachibana Masanori , Maki Taisuke , Teramoto Masaaki
Published: October 2002

The phase‐separation mechanism during porous membrane formation by the dry‐cast process was investigated by the light‐scattering method in poly(methyl methacrylate)/ethyl acetate (EA)/2‐methyl‐2,4‐pentanediol system. The evaporation of EA from the cast solution induced the phase separation and thus the porous membrane was obtained. By the light‐scattering measurement on the phase‐separation kinetics, the phase separation was found to occur by a spinodal decomposition mechanism. As the amount of nonsolvent in the cast solution decreased, the structure growth rate decreased and the growth stopped soon. The obtained porous structure was isotropic rather than asymmetric. The average interpore distances obtained from the SEM observation roughly agreed with the final constant interphase periodic distances measured by the light‐scattering method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 10: 3205–3209, 2002
Accelerated cure of phenol–formaldehyde resins: Studies with model compounds
Authors: Conner Anthony H. , Lorenz Linda F. , Hirth Kolby C.
Published: October 2002

2‐Hydroxymethylphenol (2‐HMP) and 4‐hydroxymethylphenol (4‐HMP) were used as model compounds to study the reactions that occur during cure of phenol–formaldehyde (PF) resin to which cure accelerators (ethyl formate, propylene carbonate, γ‐butyrolactone, and triacetin) have been added. The addition of cure accelerators significantly increased the rate of condensation reactions. The cure accelerators were consumed during the reaction, indicating that they do not act as true catalysts. Major dimeric and trimeric reaction products were isolated and their structures determined. The results are consistent with a mechanism in which the hydroxymethyl group of 2‐HMP (or 4‐HMP) is first transesterified by the cure accelerator. The ester group is then displaced by reaction with the negatively charged ortho or para position of a second molecule (SN2 mechanism) or is converted to a reactive quinone methide intermediate, which subsequently reacts with the negatively charged ortho or para position of a second molecule (quinone methide mechanism). When accelerators were added to the reaction mixture, the self‐condensation of 2‐HMP was faster than that of 4‐HMP. As is well documented in the literature, the exact opposite is true without added accelerators. This result would seem to indicate that the phenolic oxygen helps activate the esterified ortho‐hydroxymethyl group. The number and nature of crosslinks in a PF resin cured with added cure accelerator might be different than those in a PF resin cured without an added cure accelerator. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3256–3263, 2002
Linear thermoelastic characterization of anisotropic poly(ethylene terephthalate) films
Authors: Feng Ru , Farris Richard. J.
Published: October 2002

All nine independent elastic constants have been determined for a biaxially stretched poly(ethylene terephthalate) (PET) film using novel mechanical methods. The orthotropic directions and the in‐plane Poisson's ratios were first characterized using vibrational holographic interferometry of tensioned membrane samples. The out‐of‐plane Poisson's ratio was obtained by measuring the change in tension with the change in pressure for constant strain conditions. Pressure–volume–temperature (PVT) equipment was used to measure the bulk compressibility as well as the volumetric thermal expansion coefficient (TEC). The in‐plane Young's moduli were obtained by tensile tests, while the out‐of‐plane modulus was calculated from the compressibility and other elastic constants that describe the in‐plane behavior. The in‐plane TECs in the machine and transverse directions were determined using a thermal mechanical analyzer (TMA). The out‐of‐plane TEC was determined using these values and the volumetric TEC determined via PVT. The resulting compliance matrix satisfies all of the requirements of a positive‐definite energy criterion. The procedure of characterization utilized in this article can be applied to any orthotropic film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2937–2947, 2002
Absorption behavior of the polyester type polyols containing benzene rings toward poly(ethylene terephthalate) fiber
Authors: Yen Meng‐Shung , Cheng Chien‐Chung
Published: October 2002

Polyester‐type polyols with a single benzene ring and a double benzene ring attached to a polyethylene glycol (PEG) moiety on only one end (PT series and PTET series), or both ends (PTP series and PTETP series), or attached to a PEG and an ethylene glycol (EG) moiety each on the separate ends (PTE series and PTETE series), were synthesized, and absorption behavior of the polyester‐type polyols toward polyethylene terephthalate fibers (PET) was investigated. The results showed that all the synthesized and tested polyols structurally belonging to the single benzene ring series (whether PT, PTE, or PTP series) and a double benzene ring system with PEG attached on both ends (i.e., the PTETP series) fit nicely to the dual sorption mode of a combination of Henry type and Langmuir type. However, the other double benzene ring series, either with only PEG on one end (PTET series) or with a PEG and an EG moiety each separately attached on the two ends (PTETE series), displays a Freundlich‐type sorption. Furthermore, it was found that the HLB value of polyols, and the disposition of the PEG moiety in the structure of polyols, are also quite important in effecting the absorption parameters. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2967–2976, 2002
Free‐radical grafting of 4‐vinyl pyridine onto nylon 6 fiber
Authors: Anbarasan R. , Jayaseharan J. , Sudha M. , Gopalan A.
Published: October 2002

The chemistry of free‐radical graft copolymerization initiated with peroxomonosulfate (PMS)–thioglycolic acid (TGA) redox system has been investigated by using 4‐vinyl pyridine (4VP) as a model for nylon 6 fiber in aqueous solution under nitrogen atmosphere. Effects of concentration of 4VP, PMS, TGA, nylon 6, time, and temperature on Rh and graft parameters were studied. The FTIR spectrum of nylon 6‐g‐4VP was reported. Water retention capacity (WRC) of the grafted fiber was tested. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3108–3113, 2002
Preparation and properties of water‐soluble polyester surfactants. II. Preparation and surface activity of silicone‐modified polyester surfactants
Authors: Liu Hsin‐Jiant , Lin Li‐Huei , Chen Keng‐Ming
Published: October 2002

We prepared a novel series of water‐soluble silicone‐modified polyesters [poly(ethylene glycol) (PEG)–silicone polyesters] by reacting organopolysiloxane with a hydroxy‐terminated polyester. The polyesters were obtained by the polymerization of maleic anhydride and PEGs (molecular weights = 2000, 4000, 6000, 8000, and 10000). These water‐soluble PEG–silicone polyesters can be used as auxiliaries in dyeing process because they exhibit good surface activities such as surface tension, low foaming, and wetting power. The presence of these surfactants also retarded the rate of nylon dyeing with acid dyes. The retarding effect and low‐foaming property of these novel PEG–silicone polyesters make it possible for these surfactants to be used as leveling agents for modern nylon dyeing with acid dyes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3005–3012, 2002
Metal‐chelated polyamide hollow fibers for human serum albumin separation
Authors: Uzun Lokman , Denizli Adil
Published: October 2002

We modified microporous polyamide hollow fibers by acid hydrolysis to amplify the reactive groups and subsequent binding of Cibacron Blue F3GA. Then, we loaded the Cibacron Blue F3GA‐attached hollow fibers with different metal ions (Cu2+, Ni2+, and Co2+) to form the metal chelates. We characterized the hollow fibers by scanning electron microscopy. The effect of pH and initial concentration of human serum albumin (HSA) on the adsorption of HSA to the metal‐chelated hollow fibers were examined in a batch system. Dye‐ and metal‐chelated hollow fibers had a higher HSA adsorption capacity and showed less nonspecific protein adsorption. The nonspecific adsorption of HSA onto the polyamide hollow fibers was 6.0 mg/g. Cibacron Blue F3GA immobilization onto the hollow fibers increased HSA adsorption up to 147 mg/g. Metal‐chelated hollow fibers showed further increases in the adsorption capacity. The maximum adsorption capacities of Co2+‐, Cu2+‐, and Ni2+‐chelated hollow fibers were 195, 226, and 289 mg/g, respectively. The recognition range of metal ions for HSA from human serum followed the order: Ni(II) > Cu(II) > Co(II). A higher HSA adsorption was observed from human serum (324 mg/g). A significant amount of the adsorbed HSA (up to 99%) was eluted for 1 h in the elution medium containing 1.0M sodium thiocyanide (NaSCN) at pH 8.0 and 25 mM ethylenediaminetetraacetic acid at pH 4.9. Repeated adsorption–desorption processes showed that these metal‐chelated polyamide hollow fibers were suitable for HSA adsorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3346–3354, 2002
Studies on the photodegradation of polarized UV‐exposed PMDA–ODA polyimide films
Authors: Ha KiRyong , West John L.
Published: October 2002

Polarized Fourier transform infrared (FTIR) and ultraviolet‐visible (UV‐VIS) spectroscopy were used to investigate the photodegradation direction of polarized UV (PUV)‐irradiated polyimide (PI) films based on pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA). PI films strongly absorb below 350 nm, resulting in a photochemical reaction of the PI. PUV irradiation of the PI film caused a decrease of all existing peaks and formation of new peaks at 3258, 1748, and 1710 cm−1 in the IR, due to degradation of the PI molecules. The preferential degradation of PI molecules parallel to the PUV irradiation direction results in the predominant orientation of the remaining PI molecules perpendicular to the PUV irradiation direction. But rubbing of the PI films induced orientation of the PI molecules parallel to the rubbing direction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3072–3077, 2002
Surface migration of carboxylic acid in styrene–butadiene rubber and its tribological consequences
Authors: Bielinski D. , Glab P. , Slusarski L. , Boiteux G. , Chapel J.‐P.
Published: October 2002

Surface migration of the carboxylic acids (C10H21COOH, C11H23COOH, C12H25COOH, C15H31COOH, C16H33COOH, and C17H35COOH) in styrene–butadiene rubber (SBR) matrix was investigated together with its influence on tribological properties of the vulcanisates. Macro‐ and microtribological properties were correlated with properties that come from carboxylic acid addition to the samples. A plastifying effect was characterized by a decrease of the rubber glass transition temperature measured by the DSC method. Thickness of an acid bloom was directly determined from an indentation experiment and estimated from the DSC curve as well as from FTIR reflection spectra. Morphology of the bloom was studied using an AFM technique to characterize topography as well as microroughness of the bloom surface. Macrofriction was studied using block‐on‐ring tribometer. Microfriction was examined with a Nano Test apparatus, applying ball‐on‐plate contact. Despite correlation found between plastification, morphology, and bloom thickness on the one hand, and tribologic properties of the rubber on the other hand, influence of the chain length of carboxylic acids on properties of the samples still needs further qualitative investigation. Tribological properties of SBR modified with carboxylic acids are the result of balance of two opposite effects: plastification of rubber—leading to an increase of friction and lubrication—which causes a decrease of friction of the rubber. Apart from plastifying and lubrication effects microroughness also plays an important role in friction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3368–3376, 2002
Radiation preparation of ultrafine carboxylated styrene–butadiene rubber powders and application for nylon 6 as an impact modifier
Authors: Peng Jing , Zhang Xiaohong , Qiao Jinliang , Wei Genshuan
Published: October 2002

Ultrafine carboxylated styrene–butadiene rubber(CSBR) powders were prepared by using gamma irradiation and following spray‐drying method. The influences of dose rate, absorbed dose, and sensitizer content on the crosslinking density of CSBR latices were studied in detail. Then the ultrafine CSBR powders were used to toughen nylon 6. The toughness and thermal properties of nylon 6/CSBR blends were measured by using notched lzod impact test and differential scanning calorimetry and thermogravimetry, respectively. Results showed that the crosslinking density of CSBR increased with increasing of dose and sensitizer content, and it is independent on dose rate. The notched Izod impact strength of nylon 6 under room temperature increased after incorporation of irradiation crosslinked CSBR powders with appropriate crosslinking density. The morphology of higher impact nylon 6/CSBR blends indicated that the finer dispersion existed with dispersed particles of 150‐nm diameter. Fracture morphology of nylon 6/CSBR blend suggested that the shear yielding in matrix is the primary toughening mechanism for nylon 6/CSBR blends. The crystallinity of nylon 6/CSBR blends decreased slightly compared with pure nylon 6, whereas the addition of CSBR powders had little influence on the thermal stability of nylon 6. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3040–3046, 2002
Direct measurement of additive migration from low‐density polyethylene as a function of space and time
Authors: Helmroth I. E. , Bekhuis H. A. M. , Linssen J. P. H. , Dekker M.
Published: October 2002

A method, based on microtoming and GC analysis, for studying migration of additives inside polymers as a function of space and time was validated for Irganox 1076 migrating from low‐density polyethylene to ethanol. The consistency of the mass balance of the total amount of Irganox 1076 in the polymer and the solvent after different incubation times was acceptable considering errors introduced by the analytical procedure. A solution of Fick diffusion equations, fitted to concentration profiles inside the polymer at different incubation times, was found to describe well the transport process as a function of both position and time with a diffusion coefficient of 1.1 × 10−13 m2 s−1. This value corresponded to the diffusion coefficient obtained using conventional measurements of an Irganox 1076 concentration in ethanol as a function of time. Compared to a stationary solvent, no significant effect was observed on the diffusion coefficient by gently shaking the ethanol. Diffusion coefficients measured at different temperatures using the validated method followed an Arrhenius type of relationship with an activation energy of 113 kJ mol−1. Conclusively, the method was found to be well suitable for studying additive migration in polymers as a function of both space and time. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3185–3190, 2002
Synthesis and properties of chitosan‐modified poly(vinyl acetate)
Authors: Don Trong‐Ming , King Chia‐Fong , Chiu Wen‐Yen
Published: October 2002

A redox initiator, cerium ammonium nitrate, was used to initiate the graft copolymerization of vinyl acetate (VAc) onto the chitosan chain in a dispersion polymerization at 60°C. With an addition of 0.5–7.5 g of chitosan based on 50 g of VAc, the monomer conversion was found to be between 70 and 80% after 2 h of reaction. The grafting efficiency increased with the amount of chitosan added; yet, the grafting ratio increased slightly and then decreased. After the reaction, a stable dispersion system was observed and the surface of the latex particles was found to be rich in chitosan. All the experimental results indicated that the chitosan molecules not only took part in the graft copolymerization, but also served as a surfactant, providing the stability of the dispersion particles. If the dispersion aqueous solution was oven‐dried, a particulate membrane was formed. The experimental results indicated that the incorporation of poly(vinyl acetate) to the chitosan chains increased the toughness and decreased the water absorption of the chitosan material. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3057–3063, 2002
Microporous anisotropic phase inversion membranes from bisphenol A polycarbonate: Effect of additives to the polymer solution
Authors: Di Luccio Marco , Nobrega Ronaldo , Borges Cristiano P.
Published: October 2002

Phase inversion is a very flexible technique to obtain membranes with a large sort of morphologies. Membrane properties can vary greatly depending on the kind of polymer system used. Bisphenol A polycarbonate (PC) could be used as a phase inversion membrane base polymer, and presents very good properties. Nevertheless, very little information on membrane preparation using PC and the phase inversion process can be found in the literature. In this work flat‐sheet microporous membranes were obtained by the phase inversion process using the immersion precipitation technique. A new polymer system was studied, consisting of polycarbonate, N‐methyl‐2‐pyrrolidone as solvent, water as the nonsolvent, and an additive. The influence of some parameters on membrane morphology, such as polymer solution composition, exposition time before immersion into the precipitation bath, and the kind of additive was investigated. Precipitation was followed using light transmission experiments and membrane morphology was observed through Scanning Electron Microscopy (SEM). The viscosity and cloud points of all polymer solutions were also determined. The results were related to the studied synthesis parameters, using the basic principles of membrane formation by the phase inversion technique, looking forward to establishing criteria to control the morphology of flat‐sheet membranes using polycarbonate as the base polymer. The results showed that both additives were able to increase pore interconnectivity and even suppress macrovoid formation. The decrease in the miscibility region of the polymer system and increase in mass transfer resistance are found to be the determining factors during polymer solution precipitation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3085–3096, 2002
Pervaporation of methanol/methyl tert‐butyl ether mixtures through agarose/hydroxyethylcellulose blended membranes
Authors: Yoshikawa Masakazu , Yoshioka Takahiro , Fujime Junko , Murakami Akira
Published: October 2002

In this study, we investigated methanol (MeOH)/methyl tert‐butyl ether (MTBE) separation with hydroxyethylcellulose (HEC)/agarose blended membranes by applying a pervaporation technique. The membranes permeated MeOH in preference to MTBE from MeOH/MTBE mixtures. From pervaporation and sorption data, the permselectivity of HEC/agarose blended membrane was dominantly due to solubility selectivity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3408–3411, 2002
Polystyrene/Sn–Pb alloy blends. II. Effect of alloy particle surface treatment on dynamic rheological behavior
Authors: Zhang Xiang‐Wu , Pan Yi , Zheng Qiang , Yi Xiao‐Su
Published: October 2002

The effect of filler surface treatment on the dynamic rheological behaviors of polystyrene filled with Sn–Pb alloy particles was tested below and above the melting temperature (Tm) of the alloy. The mechanical relaxation relevant to the Tm of the alloy in the composite was diminished by the filler surface pretreatment. In the whole temperature range of interest, there existed a secondary plateau of the storage modulus at low frequencies. The effect of alloy particle surface treatment on the plateau was related to the matter‐state change (from solid to liquid) of the alloy. Above the Tm of the alloy, the surface treatment of the alloy affected the secondary plateau, but below the Tm, it did not. The analyses of Cole–Cole diagrams of the systems suggested that untreated and pretreated alloy fillers all retarded the relaxation processes in the molten state of polystyrene below the Tm of the alloy and that the relaxation process was separated into the high‐frequency relaxation of the phases and the low‐frequency relaxation of the droplets above the Tm. The surface treatments of the alloy filler further enhanced this action. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3173–3179, 2002
Polystyrene/Sn–Pb alloy blends. I. Dynamic rheological behavior
Authors: Zheng Qiang , Zhang Xiang‐Wu , Pan Yi , Yi Xiao‐Su
Published: October 2002

The dynamic rheological behavior of polystyrene filled with low‐melting‐point (Tm) Sn–Pb was investigated at temperatures below and above the Tm of the alloy, 183°C. In the whole temperature range of interest, there existed a secondary plateau in the plot of the dynamic storage modulus versus frequency (ω) at low ωs, and the influences of alloy content and temperature on the plateau were related to the matter state (liquid or solid) of the alloy. We believe that the secondary plateau observed below the alloy Tm was due to the network‐type structure formed by the agglomeration of solid filler particles, whereas the plateau above Tm was due to the deformability and relaxation of the liquid alloy droplets. By analyzing the Cole–Cole diagrams, we suggest that the alloy fillers retarded the relaxation processes for polystyrene melt when the temperature was lower than the Tm. However, there existed two separated relaxation processes when the temperature was higher than the Tm, that is, the high‐ω relaxation of the phases and low‐ω relaxation of the droplets. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3166–3172, 2002
Thermal behavior and morphological and rheological properties of polypropylene and novel elastomeric ethylene copolymer blends
Authors: Di Yingwei , Iannace Salvatore , Nicolais Luigi
Published: October 2002

The thermal behavior including melting and crystallization behavior and morphological and rheological properties of the blends based on an isotactic polypropylene and a novel maleated elastomeric ethylene copolymer were investigated in this work. The addition of an elastomer to polypropylene (PP) was found not to change the PP crystalline structure significantly when cooled quickly from the melt. On recrystallization at a lower cooling rate, the elastomer promotes the formation of β−pseudohexagonal PP in PP‐rich blends. In elastomer‐rich compositions, heterogeneous nucleation is hindered and homogeneous nucleation takes place. These phenomena are revealed by morphology observation: that, with increasing of the elastomer content, the system undergoes PP continuous, dual‐phase continuity and PP‐dispersed morphologies. The blend viscosity at a low shear rate range increases continuously with increasing elastomer content and shows positive deviations from the additivity rule. In the terminal zone, the dynamic storage modulus of the blends shows positive deviation from the simple mixing rule and the maximum deviation lies in the composition range of dual‐phase continuity which could be caused by a large increase in the interfacial tension. The Cox–Merz rule does not hold for the blends because of the two‐phase heterogeneous structure and its variation in steady and oscillatory shear flow. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3430–3439, 2002
Confidant support and the mental wellbeing of lesbian and gay young adults: a longitudinal analysis
Authors: Vincke John , van Heeringen Kees
Published: October 2002

Lesbian and gay young adults can experience adverse life conditions associated with their sexual minority status. It is not always easy for them to obtain the necessary social support to cope with these challenges. We used short‐term longitudinal data from a survey of 197 lesbian and gay young adults (121 males and 76 females) to investigate how and to what extent the availability of confidants affects depression, hopelessness and self‐esteem. We also investigated whether and to what extent mental health outcomes are related not only to initial levels of confidant support but also to changes regarding the availability of confidants. Data were analysed using descriptive statistics and hierarchical stepwise regression analysis. Results showed that confidant support at base level correlated only with the perceived quality of lesbian and gay friendships and not with parental acceptance. Also, change in confidant support over time seemed to be more important than its initial levels. Copyright © 2002 John Wiley & Sons, Ltd.
Sameness and difference in research on lesbian parenting
Authors: Clarke Victoria
Published: October 2002

Most psychological, social science and feminist work on lesbian parenting searches for similarities and differences between lesbian and heterosexual parents. Using a feminist constructionist approach, I identify four dimensions of difference that inform research and theorizing on lesbian parenting. These construct lesbian parenting as (i) no different from heterosexual parenting; (ii) different from heterosexual parenting and deviant; (iii) different from heterosexual parenting and transformative; and (iv) different from heterosexual parenting only because of oppression. I consider why lesbian parenting is constructed in these ways, by and for whom and for what purposes. I also assess the political costs and benefits of sameness and difference and ask whether psychologists, social scientists and feminists should abandon their search for similarities and differences in favour of a more radical research agenda. Copyright © 2002 John Wiley & Sons, Ltd.
Reduced focal adhesion kinase and paxillin phosphorylation in BCR‐ABL‐transfected cells
Authors: Cheng Keding , Kurzrock Razelle , Qiu Xiangguo , Estrov Zeev , Ku Stella , Dulski Kim M. , Wang Jean Y. J. , Talpaz Moshe
Published: October 2002

BACKGROUND

BCR‐ABL formation is critical to oncogenic transformation in chronic myelogenous leukemia and has been implicated as a key event leading to alterations in cytoskeletal structures and adhesion in the leukemic cells. The authors therefore investigated the effect of p210BCR‐ABL on actin polymerization as well as on the expression and phosphorylation state of the adhesion proteins paxillin and focal adhesion kinase (FAK).

METHODS

Transfection with BCR‐ABL constructs abrogated the ability of NIH 3T3 fibroblasts to adhere and the cells underwent striking morphologic changes.

RESULTS

Scanning electron microscopy revealed that the cells lost their elongated appearance and became rounded. This alteration was associated with significantly reduced actin polymerization. In addition, steady‐state levels of paxillin and FAK protein were increased. However, while the overall level of phosphotyrosines was also increased, the amount of tyrosine phosphorylated paxillin and FAK was reduced in the BCR‐ABL‐transfected cells as compared to the parental cells. Culture on extracellular fibronectin matrix partially reversed the morphologic changes and resulted in a return, albeit incomplete, of filamentous actin in BCR‐ABL‐transfected 3T3 fibroblasts. In addition, phosphorylation of paxillin and FAK in the BCR‐ABL‐transfected NIH 3T3 cells was restored.

CONCLUSIONS

The authors conclude that, in the current system, transfection of BCR‐ABL attenuates FAK and paxillin phosphorylation and reduces actin polymerization, events accompanied by significant alterations in cellular morphology. The observation that exposure of the cells to fibronectin partially reverses all these changes suggests that the focal adhesion proteins and actin structures nevertheless remain responsive to singnaling from the outside. Cancer 2002;95:440–50. © 2002 American Cancer Society.

DOI 10.1002/cncr.10670
Influence of p53 mutations on prognosis of patients with glioblastoma
Authors: Shiraishi Shoji , Tada Kenji , Nakamura Hideo , Makino Keishi , Kochi Masato , Saya Hideyuki , Kuratsu Jun‐ichi , Ushio Yukitaka
Published: October 2002

BACKGROUND

The influence of p53 mutations on the biology of astrocytic tumors is controversial. p53 is thought to be inactivated in the early stage of gliomagenesis; however, what role its inactivation plays in the malignancy of gliomas remains unknown. To understand the significance of p53 inactivation, the authors identified the locus of p53 gene mutation in glioma samples at different stages of progression and studied the correlation between the mutation and clinical behavior.

METHODS

Samples from newly diagnosed gliomas, including pure and mixed astrocytomas, were analyzed for p53 mutations using a yeast functional assay. To determine the locus of the gene mutations, DNA sequencing was performed.

RESULTS

The incidence of p53 mutations was higher in anaplastic astrocytomas (AA, 48%) than glioblastomas (GBM, 31%). There was no significant difference in the average ages of GBM patients with and without p53 mutations (54.9 years ± 2.3 and 53.2 years ± 4.6, respectively). In GBM patients, the mutation did not affect progression free survival or overall survival. Astrocytomas and GBM differed in the distribution of p53 mutation loci.

CONCLUSIONS

The p53 gene mutation does not markedly affect the survival of GBM patients. The difference in the location of p53 mutations between AA and GBM suggests that in gliomas, the p53 mutation may contribute not only to tumorigenesis (as an early event) but also to progression to malignancy (as a late event). Cancer 2002;95:249–57. © 2002 American Cancer Society.

DOI 10.1002/cncr.10677
Prophylactic bilateral mastectomy
Authors: Metcalfe Kelly A. , Goel Vivek , Lickley Lavina , Semple John , Narod Steven A.
Published: October 2002

BACKGROUND

Many women who are at an elevated risk of developing breast carcinoma choose prophylactic mastectomy to decrease their risk. We conducted a population‐based study to review the indications for, and patterns of practice of prophylactic mastectomy in Ontario, Canada, since 1991.

METHODS

A medical chart review was conducted at 33 hospitals that were identified as having conducted at least one prophylactic mastectomy. All bilateral mastectomy patients with no diagnosis of invasive or in situ breast carcinoma were eligible.

RESULTS

The number of prophylactic bilateral mastectomies performed varied from 6 to 19. The mean age of women undergoing prophylactic mastectomy was 43.5 years. Eighty percent of the women had prophylactic mastectomy performed because of a family history of breast carcinoma (89 of 99) or because of a known BRCA1 or BRCA2 mutation (10 of 99). Twenty percent of the women had no family history, but had the surgery for other benign breast conditions. Women with a family history of breast carcinoma were much more likely to have a total mastectomy (89%) than a subcutaneous mastectomy (11%). Sixty percent of the women had reconstructive surgery following mastectomy.

CONCLUSIONS

Prophylactic mastectomy is not performed on a large scale. The introduction of genetic testing for BRCA1 and BRCA2 has the potential to change the patterns of practice for prophylactic mastectomy. Cancer 2002;95:236–42. © 2002 American Cancer Society.

DOI 10.1002/cncr.10680
A controlled comparison of eye movement desensitization and reprocessing versus exposure plus cognitive restructuring versus waiting list in the treatment of post‐traumatic stress disorder
Authors: Power Kevin , McGoldrick Theresa , Brown Keith , Buchanan Robin , Sharp Donald , Swanson Vivien , Karatzias Athanasios
Published: October 2002

A total of 105 patients with post‐traumatic stress disorder (PTSD) were randomly allocated to eye‐movement desensitization and reprocessing (EMDR) (n = 39) versus exposure plus cognitive restructuring (E + CR) (n = 37) versus waiting list (WL) (n = 29) in a primary care setting. EMDR and E + CR patients received a maximum of 10 treatment sessions over a 10‐week period. All patients were assessed by blind raters prior to randomization and at end of the 10‐week treatment or waiting list period. EMDR and E + CR patients were also assessed by therapists at the mid‐point of the 10‐week treatment period and on average at 15 months follow‐up. Patients were assessed on a variety of assessor‐rated and self‐report measures of PTSD symptomatology including the Clinician Administered PTSD Scale (CAPS), the Impact of Events Scale (IOE) and a self‐report version of the SI‐PTSD Checklist. Measures of anxiety and depression included the Montgomery Asberg Depression Rating Scale (MADRS), the Hamilton Anxiety Scale (HAM‐A) and the Hospital Anxiety and Depression Scale (HADS). A measure of social function, the Sheehan Disability Scale was also used. Drop‐out rates between the three groups were 12 EMDR, 16 E + CR and five WL. Treatment end‐point analyses were conducted on the remaining 72 patients. Repeated measures analysis of variance of treatment outcome at 10 weeks revealed significant time, interaction and group effects for all the above measures. In general there were significant and substantial pre–post reductions for EMDR and E + CR groups but no change for the WL patients. Both treatments were effective over WL. The only indication of superiority of either active treatment, in relation to measures of clinically significant change, was a greater reduction in patient self‐reported depression ratings and improved social functioning for EMDR in comparison to E + CR at the end of the treatment period and for fewer number of treatment sessions for EMDR (mean 4.2) than E + CR (mean 6.4) patients. At 15 months follow‐up treatment gains were generally well‐maintained with the only difference, in favour of EMDR over E + CR, occurring in relation to assessor‐rated levels of clinically significant change in depression. However, exclusion of patients who had subsequent treatment during the follow‐up period diminished the proportion of patients achieving long‐term clinically significant change. In summary, at end of treatment and at follow‐up, both EMDR and E + CR are effective in the treatment of PTSD with only a slight advantage in favour of EMDR. Copyright © 2002 John Wiley & Sons, Ltd.
Development of the cognitive processing of trauma scale
Authors: Williams Rhonda M. , Davis Mary C. , Millsap Roger E.
Published: October 2002

We developed a 17‐item scale to measure cognitive processing of traumatic experiences in two samples of college students. The Cognitive Processing of Trauma Scale (CPOTS) measures five aspects of cognitive processing: (1) Positive Cognitive Restructuring, (2) Downward comparison, (3) Resolution, (4) Denial and (5) Regrets. Confirmatory Factor Analysis confirmed the factor structure of the scale, and reliability was further established by computing the internal consistency and test–retest reliability of each subscale. Discriminant and convergent validity for the CPOTS were demonstrated by correlating the subscales with two existing measures, the Impact of Event Scale and the Stress Related Growth Scale. The scale is recommended for use in empirical studies incorporating written or spoken disclosure about a trauma as an intervention, and should also be considered for clinical use in populations who have experienced a major stressor or trauma. Copyright © 2002 John Wiley & Sons, Ltd.
Fast screening of anabolic steroids and other banned doping substances in human urine by gas chromatography/tandem mass spectrometry
Authors: Marcos J. , Pascual J. A. , de la Torre X. , Segura J.
Published: October 2002

A fast and sensitive method for the comprehensive screening of anabolic agents and other banned doping substances using gas chromatography/tandem mass spectrometry (GC/MS/MS) with an external ionization ion trap mass spectrometer is presented. The method takes advantage of the resolving power of MS/MS to eliminate background interferences, thus speeding up the chromatographic analysis. For each compound, different fragmentation reactions were studied and their collision energies optimized to obtain the best sensitivity in terms of their signal‐to‐noise ratio (S/N). A dramatic reduction in overall analysis time was achieved compared with other common approaches. More than 50 substances could finally be monitored in less than 7.4 min with detection limits (S/N >3) lower than 0.5 ng ml−1 for most of the compounds with special sensitivity requirements according to the International Olympic Committee (IOC). A validation procedure for qualitative analysis was performed. The selectivity of the method showed that no interfering peaks were observed at the retention time of the analytes. Good intermediate precision, below 25% for most of the compounds, and robustness were observed. The optimized method was successfully applied to analyse more than 100 real human urine samples with optimum sensitivity and specificity rates. Copyright © 2002 John Wiley & Sons, Ltd.
Differentiation of proliferated NG2‐positive glial progenitor cells in a remyelinating lesion
Authors: Watanabe Masahiko , Toyama Yoshiaki , Nishiyama Akiko
Published: October 2002

Cells that express the NG2 proteoglycan (NG2+ cells) constitute a large cell population in the adult mammalian central nervous system (CNS). They give rise to mature oligodendrocytes in culture and are thus considered to be oligodendrocyte progenitor cells (OPCs). They proliferate in response to a variety of insults to the CNS, but their ability to differentiate into oligodendrocytes in vivo has not been established. We used bromodeoxyuridine (BrdU) to trace the fate of NG2+ cells that proliferated in response to a chemically induced demyelinating lesion in the adult rat spinal cord. Cells that were proliferating 24 hr after lesioning were labeled by a single injection of BrdU, and their antigenic phenotype was examined at various times up to 28 days post‐lesioning (28 dpl). Initially, at 2 dpl, NG2+/BrdU+ cells were found almost exclusively at the periphery of the lesion. At 7 dpl, the number of NG2+/BrdU+ cells increased in the lesion center and decreased from the surrounding areas. The number of NG2+/BrdU+ cells inside the lesion further decreased with time, concomitant with progression of remyelination and appearance of BrdU+ mature oligodendrocytes. Double labeling with 3H‐thymidine and BrdU combined with NG2 immunohistochemistry showed that some NG2+ cells in the lesion had undergone at least two rounds of cell division. These observations strongly suggest that NG2+/BrdU+ cells that appeared in response to the demyelinating insult gave rise to mature remyelinating oligodendrocytes, providing an in vivo evidence for the differentiation of NG2+ cells into oligodendrocytes. © 2002 Wiley‐Liss, Inc.
Neurons tend to stop migration and differentiate along the cortical internal plexiform zones in the Reelin signal‐deficient mice
Authors: Tabata Hidenori , Nakajima Kazunori
Published: October 2002

The Reelin molecule plays a fundamental role in corticogenesis. After Reelin binds to its receptors, the Reelin signal is transduced through tyrosine phosphorylation of the intracellular adaptor protein disabled 1 (Dab1). The reelin‐gene‐deficient mouse, reeler, and Dab1‐deficient mouse, yotari, show disrupted positioning of neurons. Several molecules have been identified recently as being involved in Reelin signaling, however, the biological function of Reelin during cortical plate development was still unknown. We observed the migrating behavior of neurons during development in Reelin‐signal‐deficient mice. To visualize the migrating neurons directly, we introduced green fluorescent protein (GFP)‐expression vectors into the ventricular zone with an in utero electroporation system and allowed the embryos to develop in utero until they were analyzed. The result showed that the migrating cells in the mutants were morphologically indistinguishable from those of normal mice. At the stage when the GFP‐expressing cells reached the marginal zone near the pial surface and began dendrite formation in normal mice, the GFP‐positive cells were found at various deeper positions in the mutant cortex. They had the morphology of migrating cells extending leading processes toward the pial surface. By contrast, in the mutants these cells tended to stop migration along the borders of the internal plexiform zone, the irregular structure consisting mainly of dendrites in the mutant cortex. Postnatally, these neurons began to develop dendrites later than the cells in the normal cortex. During this process, some neurons above the internal plexiform zone extended and developed dendrites in the opposite direction into the internal plexiform zone. These results suggest that the abnormal positioning of neurons in the Reelin‐signal‐deficient mice is caused, at least in part, by abnormal formation of the internal plexiform zone in the mutant cortex. © 2002 Wiley‐Liss, Inc.
Optimal conditions for in vivo induction of dopaminergic neurons from embryonic stem cells through stromal cell‐derived inducing activity
Authors: Morizane Asuka , Takahashi Jun , Takagi Yasushi , Sasai Yoshiki , Hashimoto Nobuo
Published: October 2002

A method of inducing dopamine (DA) neurons from mouse embryonic stem (ES) cells by stromal cell‐derived inducing activity (SDIA) was previously reported. When transplanted, SDIA‐induced DA neurons integrate into the mouse striatum and remain positive for tyrosine hydroxylase (TH) expression. In the present study, to optimize the transplantation efficiency, we treated mouse ES cells with SDIA for various numbers of days (8–14 days). SDIA‐treated ES cell colonies were isolated by papain treatment and then grafted into the 6‐hydroxydopamine (6‐OHDA)‐lesioned mouse striatum. The ratio of the number of surviving TH‐positive cells to the total number of grafted cells was highest when ES cells were treated with SDIA for 12 days before transplantation. This ratio revealed that grafting cell colonies was more efficient for obtaining TH‐positive cells in vivo than grafting cell suspensions. When we grafted a cell suspension of 2 × 105, 2 × 104, or 2 × 103 cells into the 6‐OHDA‐lesioned mouse striatum, we observed only a few surviving TH‐positive cells. In conclusion, inducing DA neurons from mouse ES cells by SDIA for 12 days and grafting cell colonies into mouse striatum was the most effective method for the survival of TH‐positive neurons in vivo. © 2002 Wiley‐Liss, Inc.