bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aromaticity and stability of furofurans and thienothiophenes
Authors: Aihara Jun‐ichi 
Published: August 2004

AbstractThe topological resonance energy (TRE) calculated for a polycyclic π‐system cannot always be used to predict the thermodynamic or kinetic stability of the π‐system. For example, furo[3,4‐c]furan (1d) and thieno[3,4‐c]thiophene (2d) are aromatic with large positive TREs and large negative nucleus independent chemical shift (NICS) values at the ring centers. However, these heterobicycles are predicted to be very high in energy with very small HOMO–LUMO energy separations. These unusual properties of the heterobicycles are closely associated with the fact that classical resonance structures cannot be drawn for them. In general, the kinetic stability of a polycyclic π‐system reflects not only the aromaticity of the π‐system but also the kinetic stability of the polyene reference. Copyright © 2004 John Wiley & Sons, Ltd.
Solvation effects on spirooxazine to merocyanine thermal reversion kinetics in acetonitrile–water binary mixtures
Authors: Gaeva Elena B. , Pimienta V. , Metelitsa A. V. , Voloshin N. A. , Minkin V. I. , Micheau J. C. 
Published: August 2004

AbstractIn solution, the photochromic molecule 5‐methoxyspiro[indole‐phenanthrolinoxazine] (SPO) is in equilibrium with its corresponding merocyanine open isomer. In pure acetonitrile, there is about 22.5% of the open form, whereas in acetonitrile–water binary solvents this proportion increases to more than 60% when the water molar fraction χ(H2O) is around 0.80. Irradiation in the visible range leads to a photobleached steady state in which the proportion of the merocyanine open isomer decreases significantly. When irradiation is switched off, a slow thermal reversion of the closed spirooxazine to the open merocyanine takes place until the initial equilibrium position is reached. Kinetic analysis of a whole set of relaxation curves recorded at various water contents was used to establish a model involving multiple equilibria between three merocyanines in different solvation states (solvated by acetonitrile, solvated by an acetonitrile–water complex and hydrated). Their relative proportions, which are dependent on the binary mixture composition, were determined, in addition to their corresponding visible spectra. Copyright © 2004 John Wiley & Sons, Ltd.
Resonance and field/inductive substituent effects on the gas‐phase acidities of para‐substituted phenols: a direct approach employing density functional theory
Authors: Barbour Josiah B. , Karty Joel M. 
Published: August 2004

AbstractRelative gas‐phase acidities of para‐substituted phenols (1, Sub—C6H4—OH) and their ω‐substituted para‐alkylphenol analogs [2, Sub—(CH2)n—C6H4—OH] were calculated at the B3LYP/6–31+G* and AM1 levels of theory. The acidity of a substituted molecule of 2 is compared with that of the unsubstituted molecule of 2 to determine the field/inductive effect of the substituent on the acidity of 2. This field/inductive effect was extrapolated to n = 0, yielding the field/inductive effect of the substituent on the acidity of 1. The derived field/inductive effect in 1 was subtracted from the difference in acidity between 1 and phenol in order to determine the resonance effect of the substituent on the acidity of 1. Our results are compared with the field/inductive and resonance substituent parameters empirically derived from previous experimental solution studies. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and characterization of well‐defined diblock and triblock copolymers of poly(N‐isopropylacrylamide) and poly(ethylene oxide)
Authors: Hong Chun‐Yan , You Ye‐Zi , Pan Cai‐Yuan 
Published: August 2004

AbstractWell‐defined diblock and triblock copolymers composed of poly(N‐isopropylacrylamide) (PNIPAM) and poly(ethylene oxide) (PEO) were successfully synthesized through the reversible addition–fragmentation chain transfer polymerization of N‐isopropylacrylamide (NIPAM) with PEO capped with one or two dithiobenzoyl groups as a macrotransfer agent. 1H NMR, Fourier transform infrared, and gel permeation chromatography instruments were used to characterize the block copolymers obtained. The results showed that the diblock and triblock copolymers had well‐defined structures and narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight < 1.2), and the molecular weight of the PNIPAM block in the diblock and triblock copolymers could be controlled by the initial molar ratio of NIPAM to dithiobenzoate‐terminated PEO and the NIPAM conversion. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4873–4881, 2004
Iron halide mediated atom transfer radical polymerization of methyl methacrylate with N‐alkyl‐2‐pyridylmethanimine as the ligand
Authors: Zhang Huiqi , Schubert Ulrich S. 
Published: August 2004

AbstractThe controlled atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) catalyzed by iron halide/N‐(n‐hexyl)‐2‐pyridylmethanimine (NHPMI) is described. The ethyl 2‐bromoisobutyrate (EBIB)‐initiated ATRP with [MMA]0/[EBIB]0/[iron halide]0/[NHPMI]0 = 150/1/1/2 was better controlled in 2‐butanone than in p‐xylene at 90 °C. Initially added iron(III) halide improved the controllability of the reactions in terms of molecular weight control. The p‐toluenesulfonyl chloride (TsC1)‐initiated ATRP were uncontrolled with [MMA]0/[TsC1]0/[iron halide]0/[NHPMI]0 = 150/1/1/2 in 2‐butanone at 90 °C. In contrast to the EBIB‐initiated system, the initially added iron(III) halide greatly decreased the controllability of the TsC1‐initiated ATRP. The ration of iron halide to NHPMI significantly influenced the controllability of both EBIB and TsC1‐initiated ATRP systems. The ATRP with [MMA]0/[initiator]0/[iron halide]0/[NHPMI]0 = 150/1//1/2 provided polymers with PDIs ≥ 1.57, whereas those with [iron halide]0/[NHPMI]0 = 1 resulted in polymers with PDIs as low as 1.35. Moreover, polymers with PDIs of approximately 1.25 were obtained after their precipitation from acidified methanol. The high functionality of the halide end group in the obtained polymer was confirmed by both 1H NMR and a chain‐extenstion reaction. Cyclic voltammetry was utilized to explain the differing catalytic behaviors of the in situ‐formed complexes by iron halide and NHPMI with different molar ratios. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4882–4894, 2004
Reaction control in radical polymerization of di‐n‐butyl itaconate utilizing a hydrogen‐bonding interaction
Authors: Hirano Tomohiro , Higashi Kousuke , Seno Makiko , Sato Tsuneyuki 
Published: August 2004

AbstractWe have reported that intramolecular chain‐transfer reaction takes place in radical polymerization of itaconates at high temperatures and/or at low monomer concentrations. In this article, radical polymerizations of di‐n‐butyl itaconate (DBI) were carried out in toluene at 60 °C in the presence of amide compounds. The 13C‐NMR spectra of the obtained poly(DBI)s indicated that the intramolecular chain‐transfer reaction was suppressed as compared with in the absence of amide compounds. The NMR analysis of DBI and N‐ethylacetamide demonstrated both 1:1 complex and 1:2 complex were formed at 60 °C through a hydrogen‐bonding interaction. The ESR analysis of radical polymerization of diisopropyl itaconate (DiPI) was conducted in addition to the NMR analysis of the obtained poly(DiPI). It was suggested that the suppression of the intramolecular chain‐transfer reaction with the hydrogen‐bonding interaction was achieved by controlling the conformation of the side chain at the penultimate monomeric unit of the propagating radical with an isotactic stereosequence. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4895–4905, 2004
Investigation of the solid phase synthesis of tyrosine‐derived diphenol monomers with resin‐bound carbodiimide coupling reagents
Authors: Sen Gupta Anirban , Lopina Stephanie T. 
Published: August 2004

AbstractTyrosine‐derived pseudo‐polypeptides have recently been established as potential biomaterials. The bulk production of these polymers is dependant upon the convenient synthesis of tyrosine‐derived diphenolic monomers. Suitable solution phase methods for the synthesis of such monomers, with transient activated esters, have been reported previously by Kohn, J.; Langer, R. In Biomaterials Science: An Introduction to Materials in Medicine; Ratner, B. D.; Hoffman, A. S.; Schoen, F. J.; Lemons, J. E., Eds.; Academic Press: New York, 1996; pp 64–72. However, for all the methods reported by them, purification and isolation of the diphenol monomer involves rigorous extraction, column purification, or an extensive aqueous workup. These may lead to the incorporation of solvent‐based as well as inorganic impurities and also may lead to difficulties in the process scale‐up. In this article, an alternate and relatively more convenient method for the synthesis of tyrosine‐based diphenol monomers is reported. This involved the investigation of polymer resin‐bound carbodiimide in the solid‐phase synthesis of L‐tyrosine‐based diphenolic monomers. This method was found to eliminate the need for rigorous purification processes and was found to maintain reasonable yield as well as maintain purity of the final monomer product. The monomer was able to produce polymers of a reasonably high‐molecular‐weight and a narrow polydispersity. The amide bond formation by such a polymer‐tethered reagent can be described to follow a reverse‐Merrifield sense and the method is relatively convenient to scale up. The L‐tyrosine‐based diphenolic monomeric compound formed by this method was analyzed by NMR, Fourier transform infrared, and elemental microanalysis techniques for chemical structure and composition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4906–4915, 2004
The contact toxicity of indoxacarb and five other insecticides to Orius insidiosus (Hemiptera: Anthocoridae) and Aphidius colemani (Hymenoptera: Braconidae), beneficials used in the greenhouse industry
Authors: Bostanian Noubar J , Akalach Mohammed 
Published: August 2004

AbstractThe contact toxicity of indoxacarb, abamectin, endosulfan, insecticide soap, S‐kinoprene and dimethoate to Orius insidiosus (Say) and Aphidius colemani Viereck were studied in the laboratory. These beneficials are often used in the greenhouses to manage various insect pests. Indoxacarb is slow acting and therefore, to estimate lethal dosages, observations should be continued for several days until data stabilize. Seven days after treatment, the LC50 was 0.119 g AI litre−1 for O insidiosus adults and 0.019 g AI litre−1 for A colemani. At that time, the recommended field concentration was 0.479 times the LC50 for O insidiosus adults and three times the LC50 for A colemani. In contrast, indoxacarb had no adverse effect on the reproductive capacity of wasps surviving a treatment or the developing wasps in the aphid mummy. Among the other insecticides S‐kinoprene was the most innocuous while dimethoate was the most toxic to the two beneficials. The other insecticides had overlapping toxicities. Copyright © 2004 Society of Chemical Industry
Evaluation of hydrophobic and hydrophilic kaolin particle films for peach crop, arthropod and disease management
Authors: Lalancette Norman , Belding Robert D , Shearer Peter W , Frecon Jerome L , Tietjen William H 
Published: August 2004

AbstractHydrophobic and/or hydrophilic kaolin particle film treatments to peach (Prunus persica (L) Batsch) trees were evaluated for crop and pest management capabilities in six studies from 1997 to 2000. Unsprayed control and standard treatments, the latter consisting of a commercial pesticide program, were included for comparison. Treatments in initial studies were applied via handgun, which resulted in a uniform and heavy deposit of kaolin after the first application. In contrast, treatments in subsequent studies used airblast equipment, which provided a uniform but less dense coverage, even after multiple applications. Results showed that both formulations of kaolin provided control of oriental fruit moth (Grapholita molesta (Busck)), plum curculio (Conotrachelus nenuphar (Herbst)) and Japanese beetle (Popillia japonica Newman) that was comparable with or better than the standard pesticide program. Effective management of late season catfacing insects (tarnished plant bugs Lygus lineolaris (Palisot de Beauvois) and stinkbugs Acrosternum hilare (Say), Euschistus servus (Say), and E tristigmus (Say)) and leafrollers (undetermined species) was also observed, although kaolin applications significantly increased phytophagous mite (Panonychus ulmi (Koch)) levels. In contrast to arthropod management, kaolin failed to control either peach scab (Cladosporium carpophilum (Von Thümen)) or rusty spot (Podosphaera leucotricha (Ell & Ev) ES Salmon) in any of the 4 years of the study. However, hydrophobic kaolin provided effective brown rot (Monilinia fructicola (G Winter) Honey) control when applied via handgun, and partial control when applied via airblast; hydrophilic kaolin failed to provide any control. These results suggest that hydrophobicity and deposit density may be important factors for effective disease management. The application of kaolin significantly delayed fruit maturation, increased fruit size and increased soluble solids relative to the standard. This effect, attributed to a reduction in plant stress, also resulted in increased fruit number and yield on young trees, indicating that an accentuated beneficial response from kaolin applications may be possible. Copyright © 2004 Society of Chemical Industry
Modelling the interactions between phenology and insecticide resistance genes in the codling moth Cydia pomonella
Authors: Boivin Thomas , Chadœuf Joël , Bouvier Jean‐Charles , Beslay Dominique , Sauphanor Benoît 
Published: August 2004

AbstractIn the codling moth Cydia pomonella (L), insecticide resistance genes have been associated with pleiotropic effects affecting phenology. In this paper, we investigated whether an increase in the frequency of insecticide resistance in field populations of C pomonella was likely to entail significant divergences in the temporal occurrence of both susceptible and insecticide‐resistant individuals. For this purpose, we built a phenological model that provided suitable predictions of the distinct and diverging seasonal evolutions of populations of a susceptible and two insecticide‐resistant (at two and three loci) homozygous genotypes of C pomonella. Model simulations for each genotype were further compared with pheromone trap catches recorded in a field insecticide‐treated population over an 8‐year period (from 1992 to 2000), which reflected the progressive annual increase in the frequency of resistance in southeastern France. We found a significant delay in field adult emergence relative to those predicted by the homozygous susceptible model, and the magnitude of such a delay was positively correlated with increasing frequencies of insecticide resistance in the sampled field population of C pomonella. Adult emergence predicted in the theoretical population that was homozygous for resistance at two loci converged with those recorded in the field during the investigated 8‐year period. This suggested that the pleiotropic effects of resistance were likely to result in a significant phenological segregation of insecticide‐resistant alleles in the field. The results of this study emphasized the potential for pest populations exposed to chemical selection to evolve qualitatively with respect to phenology. This may raise critical questions regarding the use of phenological modelling as a forecasting tool for appropriate resistance management strategies that would take into account the diverging seasonal evolutions of both insecticide resistance and susceptibility. Copyright © 2004 Society of Chemical Industry
Ground and first‐excited global potential energy surfaces of the H2O+He complex: Predictions of ion mobilities
Authors: Chen Xin , Thachuk M. 
Published: August 2004

AbstractIon mobilities of H2O+ drifting in helium are calculated and compared with experiment. These calculations employ global potential energy surfaces of the H2O+–He complex, which in the present case were calculated ab initio at the unrestricted MP2 level of theory using a basis set of aug‐cc‐pVTZ quality, and treating the ion as a rigid body. Details are presented of the general characteristics of both the ground and first‐excited electronic states of the complex. Although only the ground‐state surface was used for the mobility calculations, the ab initio determination of the ground state necessitated the inclusion of the first‐excited state owing to the presence of a crossing between the two. This crossing is also described. Mobilities calculated from the global surfaces are in good agreement with experiment. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Leveraging legacy codes to distributed problem‐solving environments: a Web services approach
Authors: Li M. , Qi M. 
Published: August 2004

AbstractThis paper presents WSOWG, a Web‐services‐oriented wrapper generator for automatically wrapping non‐networked legacy codes as Web services for reuse in distributed problem‐solving environments. Using WSOWG, a finite element based computational fluid dynamics (CFD) legacy code has been wrapped as a Web service. A problem‐solving environment for simulating incompressible Navier–Stokes flows has also been implemented. A user makes use of the CFD service through a Web page without knowing the exact implementation of the service. In this way, a user's computing environment can be extended to a heterogeneous distributed computing environment. Performance evaluation shows that the overhead to invoke the CFD Web service generated by WSOWG using Simple Object Access Protocol (SOAP) and CORBA Internet Inter‐ORB Protocol (IIOP) is reasonable compared with that of invoking another CFD Web service manually wrapped from the CFD legacy code using SOAP only. Copyright © 2004 John Wiley & Sons, Ltd.
A simple and fast DNA compressor
Authors: Manzini Giovanni , Rastero Marcella 
Published: August 2004

AbstractIn this paper we consider the problem of DNA compression. It is well known that one of the main features of DNA sequences is that they contain substrings which are duplicated except for a few random mutations. For this reason most DNA compressors work by searching and encoding approximate repeats. We depart from this strategy by searching and encoding only exact repeats. However, we use an encoding designed to take advantage of the possible presence of approximate repeats. Our approach leads to an algorithm which is an order of magnitude faster than any other algorithm and achieves a compression ratio very close to the best DNA compressors. Another important feature of our algorithm is its small space occupancy which makes it possible to compress sequences hundreds of megabytes long, well beyond the range of any previous DNA compressor. Copyright © 2004 John Wiley & Sons, Ltd.
Implementation of a TMO‐structured real‐time airplane‐landing simulator on a distributed computing environment
Authors: Lee Min‐Gu , Lee Sunggu , Kim K. H. (Kane) 
Published: August 2004

AbstractIn real‐time simulation, the simulated system should display the same (or very close) timing behavior as the target system. The simulation accuracy is increased as the simulation time unit is decreased. Although there are several models for such systems, the TMO model is particularly appropriate due to its natural support for real‐time distributed object‐oriented programming. This paper discusses the results of the implementation of a real‐time airplane‐landing simulator on a distributed computing environment using the TMO model. Copyright © 2004 John Wiley & Sons, Ltd.
Biochemical reaction engineering for redox reactions
Authors: Wandrey Christian 
Published: August 2004

AbstractRedox reactions are still a challenge for biochemical engineers. A personal view for the development of this field is given. Cofactor regeneration was an obstacle for quite some time. The first technical breakthrough was achieved with the system formate/formate dehydrogenase for the regeneration of NADH2. In cases where the same enzyme could be used for chiral reduction as well as for cofactor regeneration, isopropanol as a hydrogen source proved to be beneficial. The coproduct (acetone) can be removed by pervaporation. Whole‐cell reductions (often yeast reductions) can also be used. By proper biochemical reaction engineering, it is possible to apply these systems in a continuous way.By cloning a formate dehydrogenase and an oxidoreductase “designer bug” can be obtained where formate is used instead of glucose as the hydrogen source. Complex sequences of redox reactions can be established by pathway engineering with a focus on gene overexpression or with a focus on establishing non‐natural pathways. The success of pathway engineering can be controlled by measuring cytosolic metabolite concentrations. The optimal exploitation of such systems calls for the integrated cooperation of classical and molecular biochemical engineering. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 254–265; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20016
Development of catalytic asymmetric reactions via chiral palladium enolates
Authors: Hamashima Yoshitaka , Sodeoka Mikiko 
Published: August 2004

AbstractThis article describes the generation of chiral palladium enolates and their application to several kinds of catalytic asymmetric reactions. Two methods to generate chiral enolates were developed using novel cationic palladium complexes 1 and 2. In these processes, water or a hydroxo ligand on palladium metal plays an important role as a nucleophile to promote the transmetallation or as a Brønsted base to abstract an acidic α‐proton of the carbonyl group. These enolates showed sufficient reactivity with various electrophiles. Using a chiral Pd enolate as a key intermediate, highly enantioselective reactions such as catalytic aldol reactions, Mannich‐type reactions, Michael reactions, and fluorination reactions were developed. The unique structures of the palladium enolate complexes were elucidated and reaction mechanisms are proposed. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 231–242; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20017
Smart materials based on self‐assembled hydrogen‐bonded comb‐shaped supramolecules
Authors: Brinke Gerrit Ten , Ikkala Olli 
Published: August 2004

AbstractBlock copolymer self‐assembly and supramolecular chemistry can be combined most naturally to prepare smart polymer nanomaterials. An attractive route is based on comb‐shaped supramolecules, obtained by attaching side chains to (co)polymers by physical (non‐covalent) interactions. Hydrogen bonding is a key element of our approach. It combines an ease of synthesis with other important approach‐specific elements, such as hierarchical self‐assembly, strongly enhanced processability, swelling, and cleaving. Functional properties discussed include anisotropic proton conductivity, switching proton conductivity, electronically conducting nanowires, polarized luminance, dielectric stacks (optical reflectivity), functional membranes, and nano objects. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 219–230; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20018