bluuebunny/crossref_metadata_2025_split huggingface dataset:
Haterumaimides J and K, Potent Cytotoxic Diterpene Alkaloids from the Ascidian Lissoclinum Species
Authors: Uddin M Jasim , Kokubo Susumu , Ueda Katsuhiro , Suenaga Kiyotake , Uemura Daisuke 
Published: October 2002

Abstract
Two unique cytotoxic diterpene alkaloids, haterumaimides J and K, were isolated from the ascidian Lissoclinum sp. Their structures were elucidated by an extensive analysis of spectral data. Haterumaimides J and K showed potent cytotoxicity against P388 cells, with IC50 values of 0.23 ng/mL and 0.45 ng/mL, respectively.
Acute myocardial infarction as the presenting symptom of acute myeloblastic leukemia with extreme hyperleukocytosis
Authors: Cohen Yossi , Amir Gail , Da'as Nael , Gillis Shmuel , Rund Deborah , Polliack Aaron 
Published: October 2002

AbstractThis case report deals with an unusual leukostatic complication in a 56‐year‐old woman with acute myeloblastic leukemia (AML) and extreme hyperleukocytosis (316 × 109/L) who presented with acute myocardial infarction (MI). After leukopheresis the patient achieved hemodynamic stabilization and rapid neurologic recovery of encephalopathy that had also developed after the infarction. Considering the central role of WBC in the remodeling of post MI myocardial tissue, it was obvious that administration of chemotherapy with its subsequent inevitable pancytopenia could impose an increased risk for further cardiac complications including myocardial rupture. Nevertheless, cytarabine‐based induction chemotherapy was initiated 3 days after admission, and she achieved prolonged complete remission. Coronary angiography disclosed segmental atherosclerosis, but the only significant obstruction was in the right coronary artery. The patient died with relapsed leukemia 7 years later without recurrence of any cardiac symptoms or signs. Autopsy disclosed segmental coronary atherosclerosis involving the LAD (60% obstruction), suggesting that atherosclerosis was a predisposing risk factor. Additional compromise to blood perfusion due to leukostasis had led to this unusual complication of AML involving a major vessel. This is the first documented case of leukostasis causing coronary artery occlusion as well as the first report of successful induction chemotherapy for AML during a myocardial infarction. Am. J. Hematol. 71:47–49, 2002. © 2002 Wiley‐Liss, Inc.
Synthesis and characterization of poly(ethylene terephthalate‐co‐isophthalate)s with low content of isophthalate units
Authors: Karayannidis George P. , Bikiaris Demetris N. , Papageorgiou George Z. , Pastras Socrates V. 
Published: October 2002

AbstractThe objective of this work was to study the effect of the introduction of low amounts of isophthalate units on the mechanical properties, crystallization rates, and thermal parameters of poly(ethylene terephthalate). For this reason a series of five random poly(ethylene terephthalate‐co‐isophthalate) copolymers, containing 0.5, 1, 1.5, 2, and 4 mol % isophthalic acid, were prepared by the melt polycondensation process. The intrinsic viscosity of copolymers ranged between 0.7 and 0.8 dL/g. The increase of isophthalate content resulted in a significant decrease of the crystallization rates, but in a small decline of tensile strength, Young's modulus, and elongation at break, whereas tensile strength at yield point remained almost unaffected. Also, a decrease in the melting point was recorded, whereas the glass‐transition temperature was only very slightly affected. The higher decrease for the aforementioned parameters was noted for the copolymer with 4 mol % isophthalate units content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1931–1941, 2002
Acetals‐induced strength increase of melamine–urea–formaldehyde (MUF) polycondensation adhesives. II. Solubility and colloidal state disruption
Authors: Zanetti M. , Pizzi A. , Beaujean M. , Pasch H. , Rode K. , Dalet P. 
Published: October 2002

AbstractThe strength improvement induced by addition of acetals such as methylal and ethylal in melamine–urea–formaldehyde (MUF) resins could be mostly ascribed to the increased effectiveness and participation of the melamine to resin cross‐linking. This phenomenon has been shown here, by matrix‐assisted laser desorption/ionization time of flight (MALDI‐TOF) mass spectroscopy, resin aging time stability, and mainly by laser light scattering, to be due to the following: (i) the increased solubility in water afforded by the acetals cosolvents of both the unreacted melamine and of the normally very much lower solubility, higher molecular weight, lower methylolated oligomers fraction, this leading to preferentially homogeneous and hence more effective reaction rather than heterogeneous reactions; and (ii) the effect that such acetals have on the size distribution of the resin colloidal particles, with the presence of acetals such as methylals markedly decreasing the average colloidal particles diameter of the resin. This latter effect appears to be due to the disruption of the molecular clustering of the MUF resin colloidal particles, but rearrangements in the size of the colloidal particles due to the decrease in surface tension of the system, which has also been noted, cannot be excluded. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1855–1862, 2002
Improvement of the photostability of isotactic polypropylene by the incorporation of ethylene
Authors: Alam Md. Shamsul , Nakatani Hisayuki , Goss Ben G. S. , Ichiki Tomohito , Liu Boping , Terano Minoru 
Published: October 2002

AbstractThe effect of the incorporation of ethylene on the photostability of isotactic poly(propylene) (iPP) was studied with the aim of improving the photostability. iPP was prepared with a random ethylene sequence (ethylene–propylene random copolymer, rPP), and the photooxidative degradation behavior was compared with that of homogeneous iPP. Both samples were thermally post‐treated under vacuum to ensure the same crystallinity. The degradation behavior was studied by infrared spectroscopy (IR), gel permeation chromatography (GPC), and temperature rising elution fractionation (TREF) measurements. The rates of hydroperoxide and carbonyl formation in the irradiated iPP increased with irradiation time for > 192 h, whereas those in the irradiated rPP are almost constant after 96 h. The change in molecular weight with the irradiation time showed similar behavior, suggesting that the degradation reaction in the irradiated rPP was suppressed after 96 h. The degradation behavior of rPP was thought to be due to the dissociation of the methyl group, which leads to the termination of degradation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1863–1867, 2002
Molecular structure and physical properties of E‐beam crosslinked low‐density polyethylene for wire and cable insulation applications
Authors: Dadbin Susan , Frounchi Masoud , Saeid M. Haji , Gangi Fazel 
Published: October 2002

AbstractCrosslinking of homemade low‐density polyethylene (LDPE) was performed by electron‐beam (EB) irradiation. The gel content of the EB‐exposed LDPE was determined by the solvent‐extraction method. The degree of crosslinking was also evaluated by a hot set measuring test. The results obtained from both the gel–sol and the hot set methods showed that the degree of crosslinking was dependent on the deposited energy in LDPE samples. Increasing the absorbed dose increased the degree of network formation. The LDPE with higher molecular weight yielded higher efficiency of crosslinking at the same irradiation dose. The effect of irradiation dose on the molecular weight between crosslinks (Mc), glass‐transition temperature, and free volume were calculated. Mechanical test results showed that the tensile strength of the samples increased with increase in the irradiation dose up to 150 kGy and then slightly decreased with further increasing the deposited energy. The elongation at break decreased with increasing the absorbed dose. The results obtained from differential scanning calorimetry exhibited a small reduction in the melting point and the degree of crystallinity of the EB‐exposed LDPE samples compared to those of the untreated samples. The effect of crosslinking on the electrical properties of the irradiated samples was insignificant. The dielectric constant of the treated samples remained nearly constant within the irradiation dose range, although the dissipation factor increased slightly with increasing the absorbed dose. The results obtained from characterizing the EB‐induced crosslinking of homemade polyethylene, including LH0030 and LH0075, showed the higher molecular weight polyethylene (LH0030) as a preferred option for wire and cable insulation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1959–1969, 2002
Viscoelastic properties of young and old human dermis: A proposed molecular mechanism for elastic energy storage in collagen and elastin
Authors: Silver Frederick H. , Seehra Gurinder P. , Freeman Joseph W. , DeVore Dale 
Published: October 2002

AbstractWe have studied the strain‐rate dependency of the viscoelastic mechanical properties of human dermis from young (23‐year‐old) and old (87‐year‐old) donors using incremental stress–strain measurements. The elastic spring constant for elastic fibers was found to be strain‐rate and age dependent, whereas that for collagen was only age dependent. Fibril lengths were observed to decrease with increased strain rates and age for both elastic and collagen fibers; however, the large decrease in collagen fibril viscosity was hypothesized to be a result of thixotropy that results when neighboring collagen fibrils slide by each other. It is concluded that the elastic spring constant measured for elastic fibers may be higher than previously reported and is consistent with stretching of α‐helical segments of elastin into a more extended conformation during the initial part of the elastic stress–strain curve. The decrease in the elastic spring constant with increased age observed is consistent with disruption of the elastic fibers and loss of α‐helical structure. The pH dependency of the elastic modulus reported previously for collagen suggests that charge–charge interactions within and between collagen molecules are involved in energy storage during stretching. Elastic energy storage is consistent with the stretching of charged pairs located in flexible regions of the collagen molecule. Shear thinning, or thixotropy of skin, is hypothesized to reflect breakage of bonds that occur between collagen fibrils. It is hypothesized that both collagen and elastin are complex macromolecules that are hybrids of flexible and rigid regions. The flexible regions reversibly store elastic energy during stretching by breakage of secondary bonds. After stretching, the flexible regions become extended and transfer stress to the rigid regions of these molecules. This prevents premature mechanical failure of collagen and elastic fibers in the dermis. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1978–1985, 2002
Toughening liquid‐crystalline polymers with polyethylenes containing epoxy functionality
Authors: Tynys A. , Hippi U. , Seppälä J. 
Published: October 2002

AbstractTo improve toughness, a liquid‐crystalline polymer (LCPs) was blended with polyethylenes containing epoxy functionality in concentrations of 2, 6, and 15 wt %. The blends were prepared with a corotating twin‐screw extruder and were injection‐molded into specimens for mechanical testing. The effect of the amount of the epoxy‐functionalized polyethylenes on the morphology and mechanical and thermal properties was studied. The toughness improved with increasing amount of functionalized polyethylene, and the blend containing 15 wt % epoxy‐functionalized polyethylene had the best toughness properties. Impact strength values up to three times higher than those of the neat LCP were achieved. However, the stiffness of the LCP concurrently decreased substantially. The morphology became much more uniform, and the melting behavior changed. The results show that considerable improvements in the toughness properties of LCPs can be achieved with epoxy‐functionalized polyethylenes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1886–1891, 2002
Morphology and hydrolysis of PCL/PLLA blends compatibilized with P(LLA‐co‐ϵCL) or P(LLA‐b‐ϵCL)
Authors: Choi Nam‐Soon , Kim Chang‐Hyeon , Cho Kuk Young , Park Jung‐Ki 
Published: October 2002

AbstractThe effect of the compatibilizers, P(LLA‐co‐ϵCL) and P(LLA‐b‐ϵCL), on the morphology and hydrolysis of the blend of poly(ϵ‐caprolactone) (PCL) and poly(L‐lactide) (PLLA) was investigated. An addition of P(LLA‐co‐ϵCL) or P(LLA‐b‐ϵCL) into the blend could enhance the compatibility between the dispersed PCL domains and the PLLA matrix. The size of the PCL domains in the PLLA/PCL (70/30) blend containing P(LLA‐co‐ϵCL) reduced more significantly with an increase in the content of the compatibilizer than that in the blend containing P(LLA‐b‐ϵCL). The molecular weight of the PLLA/PCL blend films compatibilized with P(LLA‐co‐ϵCL) or P(LLA‐b‐ϵCL) decreased during the hydrolysis and the decrease of the molecular weight of the blend films compatibilized with P(LLA‐co‐ϵCL) was much more significant than that of the blend films compatibilized with P(LLA‐b‐ϵCL). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1892–1898, 2002
Dynamic modeling of curing process of epoxy prepreg
Authors: Sun Liangfeng , Pang Su‐Seng , Sterling Arthur M. , Negulescu Ioan I. , Stubblefield Michael A. 
Published: October 2002

AbstractThe dynamic curing process was studied by using differential scanning calorimetry (DSC) and modeled by two methods. One was based on the Kissinger and Ozawa approach, in which the activation energy was taken as a constant for all the heating rates. The whole curing process was modeled with two cure reactions. Reaction 1 exhibited the behavior of the autocatalytic reaction, whereas Reaction 2 was the nth order reaction. The effect of heating rate on the preexponential factor A1 of Reaction 1 was apparent. As the heating rate increased, the A1 decreased. There was no significant effect of heating rate on the preexponential factor A2 of Reaction 2 and the reaction orders for both reactions. The calculated results showed that the contributions of these two reactions to the total curing process were very different and changed with the heating rate. Except in the early cure stage, the calculated total degree of cure agreed well with the experimental data. Another method was based on the Borchardt and Daniels kinetic approach, where the activation energy of the cure reaction at each heating rate was determined separately. The whole curing process was modeled with one autocatalytic reaction. The fitting results showed that both preexponential factor and activation energy increased with the increment of the heating rate. As in the first method, the effect of heating rate on the orders of reaction was very small. The calculated results agreed well with experimental values in the early cure stage. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1911–1923, 2002
The influence of the preparing conditions of SiO2 supported Cp2ZrCl2 catalyst on ethylene polymerization
Authors: De Fátima V. Marques Maria , Conte Anunciata 
Published: October 2002

AbstractIn this work, ethylene was polymerized by using Cp2ZrCl2 supported on silica pretreated with methylaluminoxane (MAO) as the catalyst system. The influence of the conditions for the preparation of the heterogeneous catalyst, such as temperature, washing method of the catalytic solid, MAO and metallocene concentration in the support treatment, time of MAO, and metallocene immobilization on the support, type of alkylaluminum used in the support pretreatment, and calcination temperature of the support were investigated. Aluminum and zirconium content fixed on the silica surface were determined by inductively coupled plasma emission spectroscopy. Polymer characteristics were determined by gel permeation chromatography and differential scanning calorimetry. According to the results, the activity of some supported catalysts were far higher than with the homogeneous system. Moreover, polyethylene with very high molecular weights were also obtained and with molecular weight distribution larger than those produced with the homogeneous precursor. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2054–2061, 2002
Environmental stability of electrically conductive viologen–polyaniline systems
Authors: Zhao Baozong , Neoh K. G. , Kang E. T. 
Published: October 2002

AbstractViologen–polyaniline (PANI) systems were prepared by PANI being coated onto viologen‐grafted low‐density polyethylene films. PANI in this system could undergo photoinduced doping with ultraviolet irradiation. The electrical stability of the electrically conductive viologen–PANI systems was found to be stable in air, but the conductivity decreased rapidly when the sample was treated in aqueous media of pH > 5 because of the migration of the anions out of PANI into water. However, the conductivity increased by a factor of 2 after treatment in a 1M HCl solution because of the further protonation of PANI by acid. The structural changes of these systems were monitored with ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and resistance measurements. The electrical stability of the viologen–PANI system in water could be enhanced via spin coating with poly(methyl methacrylate) (PMMA) because this layer inhibited the migration of the anions out of the system. The photoinduced doping of PANI could be carried out either before or after the spin coating of PMMA. The advantages and limitations of each method were demonstrated. A PMMA coating with a thickness of approximately 10 μm allowed a significant doping level to be achieved within a short period of irradiation and, at the same time, effectively shielded the film from the effects of the aqueous medium. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2099–2107, 2002
Evolution of the biomechanical material properties of the femur
Authors: Erickson Gregory M. , Catanese Joseph , Keaveny Tony M. 
Published: October 2002

AbstractThe biomechanical performance of long bones is dictated by four key factors: element size, element shape, loading conditions, and material properties. Our understanding of the latter of these has been mostly limited to eutherian mammals and birds, which show similarity. Whether their possession of comparable material properties reflects common ancestry or independent evolution is uncertain. In the present analysis, we tested the bending strength, modulus, and failure strains of the femur and its pterygiophore homolog in actinpterygian fish. Sixty‐nine specimens representing basal character states in seven major vertebrate crown clades were tested. These data were then coupled with avian and mammalian data from the literature and analyzed in an evolutionary context using phylogenetic character analysis. Mean values of 188 MPa for yield strength, 22.4 GPa for Young's modulus, and 8,437 μ∈ for yield strain were obtained for the long bones. Analysis of variance (ANOVA) revealed comparable values between clades that span a 30,000‐fold range of body mass. We conclude that material properties of the first long bones 475 million years ago were conserved throughout evolution. Major locomotory challenges to femora during vertebrate evolution were almost solely accomplished by modifications of element size and shape. Anat Rec 268:115–124, 2002. © 2002 Wiley‐Liss, Inc.
Age‐dependent response to insecticides and enzymatic variation in susceptible and resistant codling moth larvae
Authors: Bouvier Jean‐Charles , Boivin Thomas , Beslay Dominique , Sauphanor Benoît 
Published: October 2002

AbstractInsecticide resistance in the codling moth, Cydia pomonella, partly results from increased metabolic detoxification. The aim of this study was to follow the age variations in larval susceptibility to deltamethrin and teflubenzuron in one susceptible (S) strain, and two resistant (Rv and Rt) ones selected for resistance to deltamethrin and diflubenzuron, respectively. The age variation of the activities of cytochrome P450‐dependent monooxygenase (MFO), glutathione S‐transferases (GST), and esterases in S and both resistant strains were simultaneously investigated. The highest levels of insecticide resistance were recorded in late instars in both resistant strains, although Rv neonates exhibited enhanced resistance to deltamethrin. The involvement of an additional deltamethrin‐specific mechanism of resistance, which could be mainly expressed in early instars, was supported by previous demonstration of a kdr point mutation in the Rv strain. The cross‐resistance between deltamethrin and teflubenzuron indicated the involvement of non‐specific metabolic pathways in resistance to teflubenzuron, rather than target site modification. A positive correlation between enhanced GST activities and deltamethrin resistance suggested that this mechanism might take place into the adaptive response of C. pomonella to pyrethroids treatments. Enhanced MFO activity was recorded in each instar of the two resistant strains compared to the susceptible one. But these activities were not correlated to the responses to deltamethrin nor to teflubenzuron. In the light of these findings, studying age‐dependence of responses to selection is central to the implementation of monitoring tests of resistances, especially if the target instars are difficult to collect in the field. Arch. Insect Biochem. Physiol. 51:55–66, 2002. © 2002 Wiley‐Liss, Inc.
Significance of penetration, excretion, and transovarial uptake to toxicity of three insect growth regulators in predatory lacewing adults
Authors: Medina Pilar , Smagghe Guy , Budia Flor , del Estal Pedro , Tirry Luc , Viñuela Elisa 
Published: October 2002

AbstractTopical treatment of the predatory lacewing adults, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) before and after the onset of oviposition with diflubenzuron (DFB) at doses based on the maximum field recommended concentration resulted in a total inhibition of egg hatch due to death of the embryo. In contrast, pyriproxyfen (PYR) and tebufenozide (TEB) did not affect fecundity and egg fertility. To explain these differences in toxicity, the patterns of penetration through the cuticle, distribution inside the insect body, and excretion were studied using [14C]‐labeled isotopes of each insect growth regulator (IGR). Penetration of DFB and TEB reached about 16 and 26% in 7 days, whereas 88% of PYR had penetrated in 24 h. However, the rate of excretion for PYR was very high, compared to that of DFB and TEB. Low amounts of absorbed radioactivity were recovered from the female body with the exception of DFB, the ovaries and the eggs deposited during a week. DFB and PYR concentration reached a peak in the eggs deposited at the fourth and second day after treatment, respectively. The current data indicate the importance of penetration through the insect cuticle. However, other mechanisms are likely to be involved in the selectivity of the current IGRs towards this beneficial insect. Arch. Insect Biochem. Physiol. 51:91–101, 2002. © 2002 Wiley‐Liss, Inc.
Organizational measures as a form of knowledge management: A multitheoretic, communication‐based exploration
Authors: Lehr Jennifer K. , Rice Ronald E. 
Published: October 2002

AbstractOne form of knowledge management is the use of measures, to foster learning, to transform individual tacit understanding to shared explicit sensemaking, to evaluate and improve processes and customer service, and even to rationalize and control organizational activities and workers. This article summarizes and applies four theoretical approaches—organizational learning, sensemaking, quality management, and critical theory—to explore how measures are constructed, interpreted, and used within organizational settings as forms of knowledge management. The primary principles, the role of communication, and the role of measures are summarized for each approach. The article ends by discussing some implications of measures in general and this multitheoretic conceptualization of measures in particular for knowledge management.