bluuebunny/crossref_metadata_2025 huggingface dataset:
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

A 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

A 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

The 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

The 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

We 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

The 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

Three 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

The 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

The 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

Indoxacarb 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

The 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

Fipronil 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
Uptake, translocation and bioavailability of imidacloprid in several hop varieties
Authors: Weichel Lars , Nauen Ralf
Published: April 2004

The neonicotinoid insecticide imidacloprid is the most important insecticide in hop cultivation in Germany. A laboratory study was undertaken to investigate its systemic properties and translaminar bioavailability in hop leaves. Radiolabelled [methylene‐14C]imidacloprid was applied either alone or in combination with different additives onto leaves of several hop varieties. Uptake and translocation were evaluated 1 and 7 days after foliar application under greenhouse conditions. The uptake of imidacloprid into hop leaves was most pronounced in the first 24 h after application and only negligible amounts were taken up after this period. Significant differences in the quantitative uptake occurred when imidacloprid was combined with additives, such as Amulsol, Genapol C‐100, Hasten and LI 700. The uptake of imidacloprid applied without additives was less than 10% 7 days after application, whereas the combination with LI 700 provided 70–80% uptake. Genapol C‐100 and Amulsol induced considerable phytotoxicity at the application site. Comparing hop varieties revealed differences up to twofold in foliar penetration of imidacloprid. The translaminar and acropetal bioavailability of imidacloprid foliarly applied to hop leaves was determined by a laboratory bioassay using the damson hop aphid, Phorodon humuli (Schrank). Significantly higher mortality was observed with laboratory formulations containing imidacloprid and the additive LI700. In contrast to these results from systemic tests, contact mortality at the application site was constantly high over the testing period of 7 days, highlighting the importance of this mode of entry for aphid intoxication. Copyright © 2003 Society of Chemical Industry
Molluscicidal activity of vulgarone B against ram's horn snail (Planorbella trivolvis)
Authors: Meepagala Kumudini M , Sturtz George , Mischke Charles C , Wise David , Duke Stephen O
Published: April 2004

The ram's horn snail (Planorbella trivolvis (Say)) is an intermediate host for a digenetic trematode (Bolbophorus confusus (Krause) Dubois) that has recently been discovered to be a significant problem in commercial channel catfish (Ictalurus punctatus Raf) production ponds in the Mississippi Delta region in the USA. In these catfish ponds, the digenetic life cycle of this parasitic trematode involves two intermediate hosts, the ram's horn snail and the channel catfish, and the final host, the American white pelican (Pelecanus erythrorhynchos Gmelin). One approach to eradicate this problem is to disrupt the life cycle of the parasitic trematodes by eliminating the snails. During our search for natural‐product‐based molluscicides to control the snails in the catfish ponds, vulgarone B, isolated from the steam distillate of the aerial parts of the plant Artemisia douglasiana Besser (Asteraceae), was found to be active towards the snails with a LC50 of ca 24 µM. Channel catfish toxicity studies indicated a LC50 of ca 207 µM. Vulgarone B may be an environmentally acceptable alternative for snail control in aquaculture. Copyright © 2004 Society of Chemical Industry
Genes similar to naphthalene dioxygenase genes in trifluralin‐degrading bacteria
Authors: Bellinaso Maria De L , Henriques João AP , Gaylarde Christine C , Greer Charles W
Published: April 2004

Trifluralin (α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐dipropyl‐p‐toluidine) is a dinitroaniline compound which was first produced in the 1960s and has been used extensively as an agricultural herbicide. There are a few publications on the biodegradation of this xenobiotic compound, but to our knowledge nothing has been documented on the genetic aspects of its catabolism. In this article, we report the analysis of DNA isolated from bacteria previously shown to degrade trifluralin, using as probes the catabolic genes ndoB, todC, xyIX, catA and xyIE which encode the enzymes naphthalene 1,2‐dioxygenase, toluene dioxygenase, toluate 1,2‐dioxygenase, catechol 1,2‐dioxygenase and catechol 2,3‐dioxygenase respectively. Using PCR and hybridization analysis, the strong hybridization of the ndoB gene with DNA extracted from four trifluralin‐degrading isolates was demonstrated, although none of them was able to degrade naphthalene, as indicated by the ‘clear zone’ test. The results indicated the presence in these bacteria of a dioxygenase gene, whose product could act on trifluralin as its principal substrate, or fortuitously, by cometabolism. This is the first publication on genes in trifluralin‐degrading bacteria. Copyright © 2003 Society of Chemical Industry
Novel 3,3a,5,9b‐tetrahydro‐2H‐furo[3,2‐c][2] benzopyran derivatives: synthesis of chiral glycol benzyl ether herbicides
Authors: Kakimoto Takeshi , Koizumi Fumiaki , Hirase Kangetsu , Banba Shinichi , Tanaka Eishi , Arai Kiyoshi
Published: April 2004

Novel tricyclic 3,3a,5,9b‐tetrahydro‐2H‐furo[3,2‐c][2]benzopyran (TFB) derivatives were synthesized, and their herbicidal activities were elucidated. They were synthesized from D‐glucose as a natural chiral source. The formation of the TFB skeleton was achieved by a Friedel–Crafts type intramolecular cyclization of methyl 5‐deoxy‐2,3‐O‐dibenzyl‐5‐C‐methyl‐D‐xylofranosides. The intramolecular cyclization was dependent upon the electronic effects of the substituents at the C‐2 benzyloxy group of methyl xylofranosides. Some TFBs exhibited a remarkable herbicidal activity to annual paddy weeds, such as Echinochloa sp, without injury to the rice. Copyright © 2004 Society of Chemical Industry
Transport and distribution of lindane and simazine in a riverine environment: measurements in bed sediments and modelling
Authors: Allan Ian J , House William A , Parker Andrew , Carter Joy E
Published: April 2004

Aquatic sediments often remove hydrophobic contaminants from fresh waters. The subsequent distribution and concentration of contaminants in bed sediments determines their effect on benthic organisms and the risk of re‐entry into the water and/or leaching to groundwater. This study examines the transport of simazine and lindane in aquatic bed sediments with the aim of understanding the processes that determine their depth distribution. Experiments in flume channels (water flow of 10 cm s−1) determined the persistence of the compounds in the absence of sediment with (a) de‐ionised water and (b) a solution that had been in contact with river sediment. In further experiments with river bed sediments in light and dark conditions, measurements were made of the concentration of the compounds in the overlying water and the development of bacterial/algal biofilms and bioturbation activity. At the end of the experiments, concentrations in sediments and associated pore waters were determined in sections of the sediment at 1 mm resolution down to 5 mm and then at 10 mm resolution to 50 mm depth and these distributions analysed using a sorption–diffusion–degradation model. The fine resolution in the depth profile permitted the detection of a maximum in the concentration of the compounds in the pore water near the surface, whereas concentrations in the sediment increased to a maximum at the surface itself. Experimental distribution coefficients determined from the pore water and sediment concentrations indicated a gradient with depth that was partly explained by an increase in organic matter content and specific surface area of the solids near the interface. The modelling showed that degradation of lindane within the sediment was necessary to explain the concentration profiles, with the optimum agreement between the measured and theoretical profiles obtained with differential degradation in the oxic and anoxic zones. The compounds penetrated to a depth of 40–50 mm over a period of 42 days. Copyright © 2004 Society of Chemical Industry
Structure–antiviral activity relationships of cecropin A‐magainin 2 hybrid peptide and its analogues
Authors: Lee Dong Gun , Park Yoonkyung , Jin Ingnyol , Hahm Kyung‐Soo , Lee Hyang‐Hee , Moon Young‐Hee , Woo Eun‐Rhan
Published: April 2004

In order to elucidate the structure–antiviral activity relationship of cecropin A (1–8)‐magainin 2 (1–12) (termed CA‐MA) hybrid peptide, several analogues with amino acid substitutions were synthesized. In a previous study, it was shown that serine at position 16 in CA‐MA hybrid peptide was very important for antimicrobial activity. Analogues were designed to increase the hydrophobic property by substituting a hydrophobic amino acid residue (S→A, V, F or W, position 16) in the CA‐MA hybrid peptide. In this study, the structure–antiviral activity relationships of CA‐MA and its analogues were investigated. In particular, substitution of Ser with a hydrophobic amino acid, Val, Phe or Trp at position 16 caused a dramatic increase in the virus–cell fusion inhibitory activity. These results suggested that the hydrophobicity at position 16 in the hydrophobic region of CA‐MA is important for potent antiviral activity. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Antinematodal effect of antimicrobial peptide, PMAP‐23, isolated from porcine myeloid against Caenorhabditis elegans
Authors: Park Yoonkyung , Jang Seung‐Hwan , Lee Dong Gun , Hahm Kyung‐Soo
Published: April 2004

The antinematodal activity and mechanism of a 23‐mer antimicrobial peptide, PMAP‐23, derived from pig myeloid was investigated. PMAP‐23 displayed a strong antinematodal activity against the eggs and worms of Caenorhabditis elegans. To investigate the antinematodal mechanism of PMAP‐23, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed. C. elegans treated with PMAP‐23 showed higher fluorescence intensity by propidium iodide (PI) staining than normal cells. Confocal microscopy showed that the peptide was localized in the egg's shell and cell membrane. The action of the peptide against C. elegans membranes was examined by testing the membrane disrupting activity using liposome (PC/PS; 3:1, w/w). The result suggests that PMAP‐23 may exert its antinematodal activity by disrupting the structure of the cell membrane via pore formation or via direct interaction with the lipid bilayers. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Synthetic human insulin 4 does not activate the G‐protein‐coupled receptors LGR7 or LGR8
Authors: Lin Feng , Otvos Laszlo , Kumagai Jin , Tregear Geoffrey W. , Bathgate Ross A. D. , Wade John D.
Published: April 2004

In contrast to the cellular receptors for insulin and insulin‐like growth factors that are known to be protein tyrosine kinases, those of both insulin 3 and relaxin have recently been identified as being members of the leucine‐rich repeat‐containing G‐protein coupled receptor (LGR) family, LGR8 and LGR7, respectively. This has prompted an examination into the possibility that they might also be specific for another member of the insulin superfamily, namely, insulin 4. Towards this aim, a two‐chain peptide corresponding to the predicted primary structure of insulin 4 was prepared by solid phase synthesis. As conventional aeration and combination of the two S‐reduced chains in solution at high pH failed to produce target product, selectively S‐protected A‐ and B‐chains were prepared followed by stepwise, individual formation of each of the three disulfides, one intramolecular within the A‐chain and two intermolecular. Chemical characterization confirmed the purity and identity of the synthetic insulin 4 analogue. However, secondary structural analysis indicated that the peptide was devoid of tertiary conformation suggesting that the native peptide may well be either significantly longer in length or is similar to insulin‐like growth factor I or II in that it is a single chain product. Screening of the synthetic analogue for activation of transfected cells bearing LGR7, and LGR7 splice variant or LGR8 failed to identify a specific interaction. Thus, the in vivo structural identity of insulin 4 and its receptor (if any) as well as its potential function remains unknown. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
New analogues of laminin active fragment YIGSR: synthesis and biological activity in vitro and in vivo
Authors: Witkowska Ewa , Orłowska Alicja , Izdebski Jan , Salwa Jan , Wietrzyk Joanna , Opolski Adam
Published: April 2004

Eleven analogues of the laminin pentapeptide amide fragment Tyr‐Ile‐Gly‐Ser‐Arg‐NH2 (YIGSR‐NH2) corresponding to a B1 chain fragment of the glycoprotein laminin have been synthesized by the solid phase method, and their biological activity has been studied in vitro by a cell adhesion assay: all of them inhibited the adhesion of LLC tumor cells to laminin. The analogues were found to be more resistant to enzymatic degradation in human serum than YIGSR‐NH2 itself. Analogue DatIGSHar‐NH2 was selected for an experimental pulmonary metastasis assay in vivo: it had higher antimetastatic activity than YIGSR‐NH2. Copyright © 2003 European Peptide Society and John Wiley & Sons, Ltd.
Energy‐level diagrams of high‐spin and low‐spin molecules
Authors: De Raedt H. , Miyashita S. , Michielsen K.
Published: April 2004

The magnetic energy‐level diagrams for models of the Mn12 and V15 molecule are calculated using the Lanczos method with full orthogonalization and a Chebyshev‐polynomial‐based projector method. The effects of the Dzyaloshinskii‐Moriya interaction on the appearance of energy‐level repulsions and its relevance to the observation of steps in the time‐dependent magnetization data are studied. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum dynamics of atomic magnets
Authors: Barbara B. , Giraud R. , Tkachuk A. M.
Published: April 2004

After the first evidence for tunneling of the total angular momentum of Ho3+ in YLiF4 (insulating), where electronic and nuclear moments tunnel simultaneously (two‐body entanglement), we show that pairs of Ho3+ ions also tunnel simultaneously (four‐body entanglement). Such co‐tunneling transitions, mediated by weak dipolar interactions, are discussed in terms of a four‐spin representation including the rare‐earth nuclear spin. This study of the entanglement of pairs of distant Ho3+ ions constitutes a first step to elucidate many‐body quantum‐spin relaxation. Finally, implications on the feasibility of two‐spin qubits are discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Normal state properties of BEDT compounds
Authors: Joo N. , Meddeb D. , Charfi‐Kaddour S. , Bennaceur R. , Héritier M.
Published: April 2004

The κ‐(BEDT‐TTF)2X organic superconductors are described by a two parameter 2D surface model, in which bandwidth and departure from perfect nesting can be varied. We have studied the spin fluctuation effect on the normal state properties in a Fermi liquid approach using the RPA approximation. The calculated NMR relaxation rate exhibits a peak in 1/(T1T), which strongly decreases when the departure from the perfect nesting of the Fermi surface and the bandwidth decrease. Our calculations show also that the spin fluctuations induce an unusual resistivity temperature dependence. These results are in a good agreement with experimental data done in κ‐(BEDT‐TTF)2X, at least qualitatively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of magnetic field on the cuprate high‐Tc superconductor La2–xSrxCuO4
Authors: Lake B. , Aeppli G. , Christensen N. B. , Lefmann K. , McMorrow D. F. , Clausen K. N. , Rønnow H. M. , Vordewisch P. , Smeibidl P. , Mankorntong M. , Sasagawa T. , Nohara M. , Takagi H. , Hussey N. E.
Published: April 2004

This article discusses neutron scattering measurements on the cuprate, high transition temperature superconductor La2–xSrxCuO4 (LSCO) in an applied magnetic field. LSCO is a type‐II superconductor and magnetic flux can penetrate the material via the formation of vorticies. Phase coherent superconductivity characterized by zero resistance is suppressed to the lower field‐dependent irreversibility temperature (Tirr(H)) and occurs when the vortices freeze into a lattice. Because superconductivity is destroyed within the vortex cores, an investigation of the vortex state provides information about the ground state that would have appeared had superconductivity not intervened. Our measurements reveal that both optimally doped LSCO (x = 0.16, Tc = 38.5 K) and underdoped LSCO (x = 0.10, Tc = 29 K) have an enhanced antiferromagnetic response in a field. Measurements of the optimally doped system for H = 7.5 T show that inelastic sub‐gap spin fluctuations first disappear with the loss of finite resistivity at Tirr, but then reappear at a lower temperature with increased lifetime and correlation length compared to the normal state. In the underdoped system elastic antiferromagnetism develops below Tc in zero field, and is significantly enhanced by application of a magnetic field; phase coherent superconductivity is then established within the antiferromagnetic phase at Tirr. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic resonant excitations in High‐Tc superconductors
Authors: Sidis Y. , Pailhès S. , Keimer B. , Bourges P. , Ulrich C. , Regnault L. P.
Published: April 2004

The observation of an unusual spin resonant excitation in the superconducting state of various High‐Tc copper oxides by inelastic neutron scattering measurements is reviewed. This magnetic mode is discussed in light of a few theoretical models and likely corresponds to a spin‐1 collective mode. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ba@Pr or Pr@Ba in R123 HTSC – To be or not to be SC
Authors: Akhavan M.
Published: April 2004

In spite of the vast amount of experimental and theoretical knowledge accumulated in HTSC, the nature of the interaction driving charge carriers to form Cooper pairs below Tc is still unknown. To elucidate the controversial insulating/SC Pr123, the substitution of Pr at Ba site (Pr@Ba) with Ba at Pr site (Ba@Pr) in R123 is compared and reviewed. This might shed some light on the microscopic origin of HTSC. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐parameter scaling of the Hall effect in manganites
Authors: Ziese M.
Published: April 2004

The Hall effect, magnetoresistance and magnetization of La0.7A0.3MnO3 (A = Ca, Ba) films were measured. A scaling of the Hall resistivity with the magnitude and direction of the magnetization was observed. The scaling relation was derived within the classical side‐jump model taking the double‐exchange interaction into account. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculation of excited‐state ionization potential for boron‐like sequence
Authors: Zheng Neng Wu , Wang Tao
Published: April 2004

Excited‐state ionization potentials for boron‐like sequence with Z = 5–19 are studied systematically, using the weakest bound electron potential model theory (WBEPM theory) and iso‐spectrum‐level series conception. Nonrelativistic ionization energy is derived from the theory. Relativistic effects are included in the Breit–Pauli approximation. Comparison of the calculated excited‐state ionization potential with available experimental data is carried out for 1s22s22p 2P, 1s22s23s 2S1/2, 1 s22s23p 2P, 1s22s23d 2D5/2, 1s22s24d 2D5/2, 1s22s25d 2D5/2, and 1s22s26d 2D5/2 series. The present results depart from experimental results by no more than 0.133 eV for all 81 results for which experimental data are available. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Validated procedure for simultaneous trace level determination of the anti‐cancer agent gemcitabine and its metabolite in human urine by high‐performance liquid chromatography with tandem mass spectrometry
Authors: Sottani Cristina , Zucchetti Massimo , Zaffaroni Marco , Bettinelli Maurizio , Minoia Claudio
Published: April 2004

A sensitive, accurate and reproducible procedure has been developed for the quantitative determination of gemcitabine (2′,2′‐difluorodeoxycytidine, dFdC) and its metabolite 2′,2′‐difluorodeoxyuridine (2dFdU) in human urine. The samples (2 mL) were extracted by solid‐phase extraction (SPE) and analyzed by reversed‐phase high‐performance liquid chromatography coupled with tandem mass spectrometry (HPLC/MS/MS), operating in multiple reaction monitoring (MRM mode). This procedure was validated using 2′‐deoxycytidine as internal standard (IS). The urine assay was linear over the range 0–50 μg/L, with a limit of quantification (LLOQ) of 0.2 μg/L for gemcitabine and 1.0 μg/L for the metabolite. The respective limits of detection (LODs) for dFdC and 2dFdU were 0.05 and 0.3 μg/L. The precision and accuracy of the assay were determined on three different days. The within‐series precision was found to be always less than 8.5 and 12.7% for gemcitabine and 2dFdU, respectively. The overall precision expressed as relative standard deviation (CVr) was always less than 7.1% for both analytes. The recovery of gemcitabine was always greater than 90% with a CVr <6.3%. The measurement uncertainty determined from the validation data assessed the possibility of determining this drug and its metabolite at trace levels in urine, considering that the combined uncertainty of the whole procedure was always less than 30%. Copyright © 2004 John Wiley & Sons, Ltd.
Use of isotopically labelled octanoic acid to assess the effect of meal size on gastric emptying
Authors: Jackson Sarah J. , Bluck Leslie J. C. , Coward W. Andrew
Published: April 2004

It has been proposed that the 13C‐octanoic acid breath test (OBT) provides a safe, non‐radioactive means of measuring gastric emptying. However, deuterated octanoic acid provides a better marker when compared with scintigraphy, as the kinetics are less complex than those of the 13C label. The appearance of 2H in saliva is modelled as a two‐compartment body water system, using an asymmetric triangular gastric emptying function. This study compared the 2H‐octanoic acid saliva test (OST) with the OBT in measuring altered states of gastric emptying in the nutritional context of diet manipulation. Gastric emptying was measured using the OST and OBT in a three‐way crossover study involving 12 healthy male and female subjects (mean BMI = 23.4 kg/m2, aged 24–57 years). Following an overnight fast, subjects were given an egg meal, labelled with 10 μL/kg body weight 2H‐octanoic acid and 100 μL 13C‐octanoic acid. The meal was nutritionally manipulated to provide a 1 MJ, 2 MJ or 3 MJ meal. Breath and saliva samples were collected at regular intervals for 6 h, with further saliva samples being collected over four subsequent days. 2H isotopic enrichment in saliva and 13C isotopic enrichment in breath were analysed using isotope ratio mass spectrometry and the data fitted to the respective gastric emptying models. The half excretion time (T1/2D), time to maximum emptying rate (T1D) and time when emptying is complete (T2D) were calculated from the 2H saliva test data, and the lag time (TlagC), half excretion time (T1/2C), latency phase (TlatC) and ascension time (TascC) were calculated from the 13C breath test data. Overall, the OBT correlated well with the OST, with a significant relationship between T1/2C and T1/2D, a significant relationship between TlatC and T1D and finally a significant relationship between TascC and T2D. Gastric emptying measured using the OST was significantly faster with the 1 MJ meal (ΔT1/2D = −0.77 h vs. 2 MJ, p = 0.004). Increases were also seen when the meal size was increased from 2 MJ to 3 MJ (ΔT1/2D = +0.44 h vs. 2 MJ), but these were not significant. These trends were mirrored in the OBT data, with significant differences between 1 MJ and 2 MJ (ΔT1/2C = −0.63 h vs. 2 MJ, p = 0.013) and non‐significant increases with the larger 3 MJ meal (ΔT1/2C = +0.10 h vs. 2 MJ). Total meal calorie content was shown to have an effect on gastric emptying using both the OBT and the OST. The deuterium method allows the direct calculation of the gastric emptying function and could be used as an alternative to gamma scintigraphy, allowing further validation of the 13C‐octanoic acid breath test. Copyright © 2004 John Wiley & Sons, Ltd.
Derivatization of amino acids with N,N‐dimethyl‐2,4‐dinitro‐5‐fluorobenzylamine for liquid chromatography/electrospray ionization mass spectrometry
Authors: Liu Zhongfa , Minkler Paul E. , Lin De , Sayre Lawrence M.
Published: April 2004

Derivatization, separation and identification of amino acids with a novel compound, N,N‐dimethyl‐2,4‐dinitro‐5‐fluorobenzylamine (DMDNFB), using high‐performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI‐MS) was demonstrated. Compared to derivatization with 2,4‐dinitrofluorobenzene (DNFB), DMDNFB‐derivatized amino acids and dipeptides exhibit much larger ion current signals in the commonly used ESI positive mode, which was attributed to the introduction of the N,N‐dimethylaminomethyl protonatable site. Copyright © 2004 John Wiley & Sons, Ltd.
Identification by electrospray tandem mass spectrometry of spin‐trapped free radicals from oxidized 2‐oleoyl‐1‐palmitoyl‐sn‐glycero‐3‐phosphocholine
Authors: Reis A. , Domingues P. , Ferrer‐Correia A. J. V. , Domingues M. R. M.
Published: April 2004

GPC radical species formed during oxidation of a glycerophosphocholine (16:0/18:1) under the Fenton reaction conditions were detected using a spin trap, 5,5‐dimethyl‐1‐pyrrolidineN‐oxide (DMPO). The stable spin‐trapped radical adducts were identified by mass spectrometry (MS) using electrospray (ES) as ionization method and characterized by tandem mass spectrometry (MS/MS). Radical adducts of oxidized freesn‐2 fatty acid and of oxidized intact GPC, containing one, two and three additional oxygen atoms, were assigned. DMPO adducts of oxidized intact GPC were observed as singly and doubly charged ions in ES‐MS, while adducts of oxidized free fatty acids were observed as singly charged ions. Oxidized freesn‐2 fatty acids and intact GPC‐DMPO adducts correspond to carbon‐ and oxygen‐centered radicals that were identified by MS/MS as alkyl, hydroxy‐alkyl, alkoxyl, hydroxy‐alkoxyl, peroxyl and hydroperoxide‐alkoxyl spin adducts. The DMPO molecule was attached predominantly at C9of the oleic chain. The fragmentation pathway of spin adducts with two DMPO molecules strongly suggests the presence of species that were simultaneously carbon‐ and oxygen‐centered radicals. Several fragments identified are consistent with the presence of isomeric structures contributing to the same ions. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison of product ion spectra obtained by liquid chromatography/triple‐quadrupole mass spectrometry for library search
Authors: Gergov Merja , Weinmann Wolfgang , Meriluoto Jussi , Uusitalo Jouko , Ojanperä Ilkka
Published: April 2004

Reproducibility of product ion spectra acquired using a liquid chromatography/triple‐quadrupole mass spectrometry (LC/MS/MS) instrument over a 4‐year period, and with three other LC/MS/MS instruments, one from the same manufacturer and two from a different manufacturer, was examined. The MS/MS spectra of 30 drug substances were generated in positive electrospray ionization mode at low, medium, and high collision energies (20, 35, and 50 eV). Purity and Fit score percentages against a 400‐compound LC/MS/MS spectral library were calculated using an algorithm in which fragment intensity ratios and weighting factors were included. The long‐term reproducibility study was conducted using a brand A instrument; after 4 years the reproducibility of the product ion spectra was still 94%, expressed as average Purity score. The inter‐laboratory study involved two parts. Firstly, two LC/MS/MS spectral libraries, created independently in separate laboratories using brand A instruments, were compared with each other. The average Fit and Purity scores of spectra from one library against the other were better than 93 and 91%, respectively, when the same collision energies were used. Secondly, for the comparison of product ion spectra between brand A and brand B instruments, fragmentation conditions were first standardized for amitriptyline as the standard analyte. The average Fit scores of brand B spectra against the brand A spectral library varied between 79 and 85% at all three collision energies. These results indicate that, after standardizing the instrumental conditions, LC/MS/MS spectral libraries of drug substances are suitable for inter‐laboratory use. Copyright © 2004 John Wiley & Sons, Ltd.
Abstract Data Types Can HaveInequations
1
Authors: Kondoh Hidetaka
Published: April 2004

Abstract.

This work proposes a typed functional wide-spectrum
language, Funiq, for both programming and specification as an
extension of Cardelli-Wegner’s Fun enriched with the fixed-point
construction on expressions and inequational refinements (as
assertions) for types. The type system of our wide-spectrum
Funiq language is shown to be a conservative extension of that
of the original Fun and sound with respect to the complete PER
semantics for types.