bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaction of carbon dioxide with glycidol: The synthesis of a novel hyperbranched oligomer with a carbonate main chain with a hydroxyl terminal
Authors: Motokucho Suguru , Sudo Atsushi , Sanda Fumio , Endo Takeshi 
Published: April 2004

AbstractA novel branched polycarbonate with a hydroxyl group at the chain end was synthesized by the copolymerization of glycidol with carbon dioxide (CO2). The copolymerization was carried out with 5 mol % of an alkali metal halide or quaternary ammonium salt as a catalyst under atmospheric CO2. The obtained poly(glycidol‐co‐carbon dioxide) was O‐benzoylated and O‐silylated, and the corresponding polymers were analyzed with IR, size exclusion chromatography, 13C NMR, and 29Si NMR. The IR spectroscopy analysis of the O‐benzoylated polymer revealed that the maximum incorporation degree of the carbonate group was 90% (i.e., the CO2/glycidol composition ratio was 0.9:1.0). The incorporation of CO2 as a carbonate unit was also confirmed by the treatment of this polymer with n‐butylamine, which caused the aminolysis of the carbonate and led to degraded products. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2506–2511, 2004
13Carbon nuclear magnetic resonance of ethylene–propylene–1‐hexene terpolymers
Authors: Escher Fernanda F. Nunes , Galland Griselda Barrera 
Published: April 2004

AbstractWe report the complete 13C NMR characterization of a series of ethylene–propylene–1‐hexene terpolymers obtained with the metallocenic system rac‐ethylene bis‐indenyl zirconium dichloride, with different comonomer ratios. A detailed study of 13C NMR chemical shifts, triad sequence distributions, monomer‐average sequence lengths, and reactivity ratios for these terpolymers is presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2474–2482, 2004
Polyelectrolyte complexes. VI. Polycation structure, polyanion molar mass, and polyion concentration effects on complex nanoparticles based on poly(sodium 2‐acrylamido‐2‐methylpropanesulfonate)
Authors: Dragan Ecaterina Stela , Schwarz Simona 
Published: April 2004

AbstractThe formation and characterization of some interpolyelectrolyte complex (IPEC) nanoparticles based on poly(sodium 2‐acrylamido‐2‐methylpropanesulfonate) (NaPAMPS), as a function of the polycation structure, polyanion molar mass, and polyion concentration, were followed in this work. Poly(diallyldimethylammonium chloride) and two polycations (PCs) containing (N,N‐dimethyl‐2‐hydroxypropyleneammonium chloride) units in the backbone (PCA5 and PCA5D1) were used as starting polyions. The complex stoichiometry, (n−/n+)iso, was pointed out by optical density at 500 nm (OD500), polyelectrolyte titration, and dynamic light scattering. IPEC nanoparticle sizes were influenced by the polycation structure and polyanion molar mass only before the complex stoichiometry, which was higher for the more hydrophilic polycations (PCA5 and PCA5D1) and for a higher NaPAMPS molar mass, and were almost independent of these factors after that, at a flow rate of the added polyion of about 0.28 mL × (mL PC)−1 × h−1. The IPEC nanoparticle sizes remained almost constant for more than 2 weeks, both before and after the complex stoichiometry, at low concentrations of polyions. NIPECs as stable colloidal dispersions with positive charges in excess were prepared at a ratio between charges (n−/n+) of 0.7, and their storage colloidal stability, as a function of the polycation structure and polyion concentration (from 0.8 to ca. 7.8 mmol/L), was demonstrated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2495–2505, 2004
Reversible addition–fragmentation chain transfer polymerization of glycidyl methacrylate with 2‐cyanoprop‐2‐yl 1‐dithionaphthalate as a chain‐transfer agent
Authors: Zhu Jian , Zhou Di , Zhu Xiulin , Chen Gaojian 
Published: April 2004

AbstractA reversible addition–fragmentation chain transfer (RAFT) agent, 2‐cyanoprop‐2‐yl 1‐dithionaphthalate (CPDN), was synthesized and applied to the RAFT polymerization of glycidyl methacrylate (GMA). The polymerization was conducted both in bulk and in a solvent with 2,2′‐azobisisobutyronitrile (AIBN) as the initiator at various temperatures. The results for both types of polymerizations showed that GMA could be polymerized in a controlled way by RAFT polymerization with CPDN as a RAFT agent; the polymerization rate was first‐order with respect to the monomer concentration, and the molecular weight increased linearly with the monomer conversion up to 96.7% at 60 °C, up to 98.9% at 80 °C in bulk, and up to 64.3% at 60 °C in a benzene solution. The polymerization rate of GMA in bulk was obviously faster than that in a benzene solution. The molecular weights obtained from gel permeation chromatography were close to the theoretical values, and the polydispersities of the polymer were relatively low up to high conversions in all cases. It was confirmed by a chain‐extension reaction that the AIBN‐initiated polymerizations of GMA with CPDN as a RAFT agent were well controlled and were consistent with the RAFT mechanism. The epoxy group remained intact in the polymers after the RAFT polymerization of GMA, as indicated by the 1H NMR spectrum. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2558–2565, 2004
Synthesis of metal/polymer colloidal composites by the tailored deposition of silver onto porous polymer microspheres
Authors: Kim Jin‐Woong , Lee Jung‐Eun , Ryu Jee‐Hyun , Lee Jong‐Suk , Kim Su‐Jin , Han Sang‐Hoon , Chang Ih‐Seop , Kang Hak‐Hee , Suh Kyung‐Do 
Published: April 2004

AbstractA new colloidal silver system is presented in which a fine colloidal silver is in situ deposited onto functionalized porous poly(ethylene glycol dimethacrylate) [poly(EGDMA)] microspheres. The effectiveness of the silver deposition has been investigated through an examination of the surface characteristics of poly(EGDMA) microspheres. The result reported in this study demonstrate that the control of the surface area and surface functionality (in this study, a hydroxyl group) of poly(EGDMA) microspheres is an important factor that practically determines the degree of deposition of colloidal silver. X‐ray analysis has shown that silver nanoparticles are dispersed evenly on inner and outer surfaces and have a face center cubic phase. Preservation testing has shown that silver‐containing poly(EGDMA) microspheres have powerful antibacterial properties and, therefore, have significant potential as new preservatives. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2551–2557, 2004
Effects of the alkyl side‐chain length on the structures of poly[oxy(N‐alkylsulfonylmethyl)ethylene]s
Authors: Park Soo‐Young , Farmer B. L. , Lee Jong‐Chan 
Published: April 2004

AbstractThe structures of poly[oxy(N‐alkylsulfonylmethyl)ethylene]s (ASE‐Ns) were examined with X‐ray, IR, DSC, and polarized optical microscopy. The structures of ASE‐Ns were strongly dependent on the alkyl side‐chain length. ASE‐2 and ASE‐3, the shortest ones, were amorphous materials. ASE‐4 and ASE‐5 showed nematic characteristics. ASE‐6–ASE‐12 had smectic A structures. ASE‐14 and ASE‐16 could be labeled as more ordered structures higher than smectic A (probably smectic B or smectic E). The d‐spacings of the first small‐angle reflections were double the most extended side‐chain length and linearly increased with a slope of 2.50 Å per methylene unit, regardless of the structural phases. The maintenance of the double‐layered structure in all ASE‐Ns may be due to the strong dipole–dipole interactions at both sides of the layers against the main chain for all amorphous, nematic, and smectic phases of ASE‐Ns. The double‐layered structure was maintained above the isotropic temperature, indicating that dipole–dipole interactions were not destroyed although the alkyl side chains melted during the isotropic transition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1868–1874, 2004
Does conventional nucleation occur during phase separation in polymer blends?
Authors: Balsara Nitash P. , Rappl Timothy J. , Lefebvre Amy A. 
Published: April 2004

AbstractThe kinetics of liquid–liquid phase separation in off‐critical polymer blends was studied with time‐resolved small‐angle neutron scattering. Our objective was to study the nature of the nuclei that formed during the initial stages of the phase transition. The blends were composed of model polyolefins—deuterium‐labeled poly(methyl butylene) (PMB) and poly(ethyl butylene) (PEB)—with molecular weights of about 200 kg/mol. A direct examination of the initial clustering of molecules before macroscopic phase separation was possible because of the large size of the polymer chains and concomitant entanglement effects. We discovered that the scattering profiles obtained during nucleation merged at a well‐defined critical scattering vector. We propose that this is the signature of the critical nucleus and that the size of the critical nucleus is inversely proportional to the magnitude of the critical scattering vector. The kinetic studies were preceded by a thorough characterization of the equilibrium thermodynamic properties of our PMB/PEB blends. The locations of the binodal and spinodal curves of our system are consistent with predictions based on the Flory–Huggins theory. This combination of thermodynamic and kinetic experiments enabled the quantification of the dependence of the size and structure of the critical nuclei on the quench depth. Our results do not agree with any of the previous theories on nucleation. Some aspects of our results are addressed in recent theoretical work by Wang in which the effects of fluctuations on the classical binodal and spinodal curves in polymer blends are incorporated. Both theory and experiment support the notion that the traditional stability limit (spinodal) should be replaced by a metastability limit. Although Wang's theory provides an explanation for some of our observations, many fundamental issues regarding nucleation in polymer blends remain unresolved. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1793–1809, 2004
Proton transfer in nafion membrane by quantum chemistry calculation
Authors: Tanimura Shinobu , Matsuoka Takaaki 
Published: April 2004

AbstractWe estimated the energy barriers of proton transfers in the systems of (CF3SO3/H/SO3CF3)− and (CF3SO3/H/H2O/SO3CF3)− as models of a water‐swollen Nafion membrane by an ab initio density functional quantum calculation method with consideration of the hydration effect. As a result, the proton transfer between the SO sites, which is accompanied by one water molecule, was found to be one of the proton‐transfer mechanisms in the water‐swollen Nafion membrane; that is, the surface diffusion mechanism was found to be important for the proton transfer in that membrane. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1905–1914, 2004
Rheooptical investigation of the crystallization of poly(ethylene terephthalate) under tensile strain
Authors: Chaari F. , Chaouche M. 
Published: April 2004

AbstractThe crystallization of poly(ethylene terephthalate) under uniaxial tensile strain at different extension rates was investigated with optical polarimetry in a temperature range between the glass‐transition temperature and the quiescent crystallization temperature. The evolution of the optical properties of the polymer, including the turbidity, birefringence, and dichroism, were monitored simultaneously with the mechanical parameters. To complete the semicrystalline microstructure characterization of the polymer under strain, an online wide‐angle X‐ray diffraction (WAXD) technique was used in separate experiments, which were performed under the same thermomechanical conditions. For real‐time measurements, a high‐energy synchrotron radiation source was used. The optical properties provided information about both the crystalline and amorphous phases, whereas the WAXD patterns essentially gave information about the crystalline phase. The two experimental techniques were then used in a complementary way to characterize the semicrystalline microstructure. Significant deviations from the stress‐optical rule were found. This was attributed to both transient effects and the appearance of crystallites, which consisted of highly oriented molecular segments that could contribute to the optical anisotropy but not necessarily to the stress. The behavior of the optical dichroism was found to be qualitatively different from that of the birefringence. The latter monotonically increased with the strain, whereas the former first increased with the strain, passed through a maximum, and then decreased to a steady‐state value. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1915–1927, 2004
Comparing greenhouse sprayers: the dose‐transfer process
Authors: Ebert Timothy A , Derksen Richard C , Downer Roger A , Krause Charles R 
Published: April 2004

AbstractThree sprayers were evaluated for their affect on retention and efficacy: a carbon dioxide powered high‐volume sprayer, a DRAMM coldfogger, and an Electrostatic Spraying Systems (ESS) sprayer with air‐assistance. The active ingredients used were spinosad and azadirachtin. The plant canopy was constructed in the greenhouse using potted soybeans (Glycine max (L) Merrill cr Pioneer 9392). Application efficacy with spinosad was assessed using thrips [Western flower thrips, Frankliniella occidentalis (Pergande)] and mite (two‐spotted spider mite, Tetranychus urticae Koch) abundance on shoots and leaves. Application efficacy with azadirachtin was assessed using thrips and aphid (soybean aphid, Aphis glycines Matsumura) abundance on shoots and leaves. The atomization characteristics of each sprayer were measured using an Aerometrics phase/Doppler particle analyzer (PDPA) 100‐1D. The results of four tests are presented. Two tests used each sprayer according to manufacturer recommendations. These are ‘recommended volume’ tests that confound differences in toxicant distribution caused by the sprayer with differences caused by changes in application volume. The other two tests were ‘constant volume’ tests in which all three sprayers were used to deliver the same application volume. Both types of test gave differences between sprayers in retention of toxicant, but only the recommended volume tests showed significant effects of the sprayers on pest abundance. We attribute this difference to the role played by changing application volumes in the dose‐transfer process. The constant‐volume tests showed that application equipment influences efficacy. Copyright © 2003 Society of Chemical Industry
The relationship between the chemical composition of three essential oils and their insecticidal activity against Acanthoscelides obtectus (Say)
Authors: Papachristos Dimitrios P , Karamanoli Katerina I , Stamopoulos Dimitrios C , Menkissoglu‐Spiroudi Urania 
Published: April 2004

AbstractThe chemical composition of the essential oils isolated from various parts of three Greek aromatic plants (Lavandula hybrida Rev, Rosmarinus officinalis L and Eucalyptus globulus Labill) collected at different seasons was determined by GC/MS analysis. The insecticidal action of these oils and of their main constituents on Acanthoscelides obtectus (Say) adults was evaluated and their LC50 values were estimated. All essential oils tested exhibited strong activity against A obtectus adults, with varying LC50 values depending on insect sex and the composition of the essential oils. A correlation between total oxygenated monoterpenoid content and activity was observed, with oxygenated compounds exhibiting higher activity than hydrocarbons. Among the main constituents, only linalyl and terpinyl acetate were not active against A obtectus, while all the others exhibited insecticidal activity against both male and female adults, with LC50 values ranging from 0.8 to 47.1 mg litre−1 air. An attempt to correlate the insecticidal activity to the monoterpenoid's structure is presented, and the difference in sensitivity between male and female individuals is also explored. Copyright © 2004 Society of Chemical Industry
Visualisation of the uptake of two model xenobiotics into bean leaves by confocal laser scanning microscopy: diffusion pathways and implication in phloem translocation
Authors: Liu Zhiqian , Gaskin Robyn E 
Published: April 2004

AbstractThe diffusion of two fluorescent dyes, Oregon Green 488 (Oregon Green) and Rhodamine B into the leaves of broad bean (Vicia faba L) plants was studied to simulate the foliar uptake process of pesticides. The uptake rate of these model xenobiotics into bean foliage was measured using a standard leaf surface wash‐off method. Diffusion into leaf tissues was visualised in vivo by confocal laser scanning microscopy (CLSM). The moderately lipophilic dye (Rhodamine B) showed faster uptake than the hydrophilic one (Oregon Green), despite the former being a larger molecule. While no distinct channels or domains for preferential entry of any of the dyes could be detected in the cuticle layer by CLSM, two different diffusion patterns were identified for the movement of these two dyes after traversing the cuticle. Upon desorption from the cuticle, Rhodamine B diffused extensively into the vacuole of the epidermal cells. Further transport of this dye from the epidermal cells to the mesophyll cells was not observed. In contrast, Oregon Green was found in the epidermal cell walls and cytoplasm, and was also present in the mesophyll cells. Examination of the petioles of the treated leaves revealed that, once absorbed, Oregon Green moved readily out of the treated leaf, whereas Rhodamine B did not show any phloem translocation. It is proposed that these two different diffusion characters may be responsible for the contrasting phloem mobility of the two xenobiotics. The results are discussed in relation to the current knowledge on the uptake, translocation and efficacy of pesticides as influenced by their properties. Copyright © 2004 Society of Chemical Industry
Toxicity of indoxacarb to two species of predacious mites and a predacious Mirid
Authors: Bostanian Noubar J , Vincent Charles , Hardman John M , Larocque Nancy 
Published: April 2004

AbstractIndoxacarb is a novel oxadiazine pro‐insecticide that has no toxic effects on the adults, fecundity and eclosion of Amblyseius fallacis (Garman), a predacious phytoseiid, or Agistemus fleschneri Summers, a predacious stigmaeid. It is toxic to Hyaliodes vitripennis (Say), a predacious mirid that has been reported from several Quebec orchards where IPM programs are used. The LC50 for this mirid is about one‐half of the recommended dose (0.054 g AI litre−1) of indoxacarb for apple orchards. Following an application, the intoxicated mirids remained motionless as their prolegs and posterior had paralyzed. Twenty‐four hours later, they appeared smaller, shrunken and severely desiccated. For the Department of Agriculture and Agri‐Food, Government of Canada, © Minister of Public Works and Government Services Canada 2004. Published for SCI by John Wiley & Sons, Ltd
Synergism of insecticides provides evidence of metabolic mechanisms of resistance in the obliquebanded leafroller Choristoneura rosaceana (Lepidoptera: Tortricidae)
Authors: Ahmad Mushtaq , Hollingworth Robert M 
Published: April 2004

AbstractThe interactions between six insecticides (indoxacarb, cypermethrin, chlorpyrifos, azinphos‐methyl, tebufenozide and chlorfenapyr) and three potential synergists, (piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by dietary exposure in a multi‐resistant and a susceptible strain of the obliquebanded leafroller, Choristoneura rosaceana (Harris). The synergists did not produce appreciable synergism with most of the insecticides in the susceptible strain. Except for tebufenozide, PBO synergized all the insecticides to varying degrees in the resistant strain. A very high level of synergism by PBO was found with indoxacarb, which reduced the resistance level from 705‐ to 20‐fold when PBO was administered alone and to around 10‐fold when used in combination with DEF. DEF also synergized indoxacarb, cypermethrin, chlorpyrifos, azinphos‐methyl and tebufenozide in the resistant strain. DEM produced synergism of indoxacarb, chlorpyrifos, azinphos‐methyl and chlorfenapyr in the resistant strain. DEM was highly synergistic to cypermethrin, and to some extent to tebufenozide in both the susceptible and resistant strains equally, implying that detoxification by glutathione S‐transferases was not a mechanism of resistance for these insecticides. The high level of synergism seen with DEM in the case of cypermethrin may be due to an increase in oxidative stress resulting from the removal of the antioxidant, glutathione. These studies indicate that enhanced detoxification, often mediated by cytochrome P‐450 monooxygenases, but with probable esterase and glutathione S‐transferase contributions in some cases, is the major mechanism imparting resistance to different insecticides in C rosaceana. Copyright © 2004 Society of Chemical Industry
Fipronil modulation of GABAA receptor single‐channel currents
Authors: Ikeda Tomoko , Nagata Keiichi , Kono Yoshiaki , Yeh Jay Z , Narahashi Toshio 
Published: April 2004

AbstractFipronil is the first phenylpyrazole insecticide introduced for pest control. Although fipronil is known to inhibit GABA receptors, the detailed mechanism of action remains to be seen. In order to elucidate the mechanism of fipronil interaction with the mammalian GABAA system, single‐channel patch clamp experiments were performed using rat dorsal root ganglion neurons. The amplitude of main conductance state (27 pS) current was not significantly altered by co‐application of 10 µM fipronil and 10 µM GABA. The histograms of open time distribution were fitted to a sum of three exponential functions. After application of 10 µM fipronil, the proportion of the fastest component increased slightly and that of the slowest component decreased slightly. Thus, the mean open time was decreased from 11.4 ms to 7.8 ms by fipronil. The histograms of closed time distribution were fitted to a sum of four exponential functions. Fipronil 10 µM prolonged the slowest time constant resulting in a prolongation of the mean closed time from 29.7 ms to 52.8 ms. Thus, the frequency of channel openings was reduced. Thus, the fipronil suppression of GABA‐induced whole‐cell currents is caused in part by decreases in the channel open time and the frequency of channel openings. Copyright © 2004 Society of Chemical Industry