bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity
Authors: Miyakoshi Ryo , Yokoyama Akihiro , Yokozawa Tsutomu 
Published: December 2007

AbstractWe describe the development of chain‐growth condensation polymerization for the synthesis of well‐defined π‐conjugated polymers via a new polymerization mechanism, catalyst‐transfer polymerization. We first studied the condensation polymerization of Grignard‐type hexylthiophene monomer with a Ni catalyst as a part of our research on chain‐growth condensation polymerization, and found that this polymerization also proceeded in a chain‐growth polymerization manner. However, the polymerization mechanism involving the Ni catalyst was different from that of previous chain‐growth condensation polymerizations based on substituent effects; the Ni catalyst catalyzed the coupling reaction of the monomer with the polymer, followed by the transfer of Ni(0) to the terminal CBr bond of the elongated molecule. This catalyst‐transfer condensation polymerization is generally applicable for the synthesis of polythiophene with an etheric side chain and poly(p‐pheneylene), as well as for the synthesis of polyfluorene via the Pd‐catalyzed Suzuki–Miyaura coupling reaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 753–765, 2008
Synthesis and characterization of highly stable blue‐light‐emitting hyperbranched conjugated polymers
Authors: Wang Rui , Wang Wei‐Zhi , Yang Gui‐Zhong , Liu Tianxi , Yu Junsheng , Jiang Yadong 
Published: December 2007

AbstractPolyfluorene homopolymer (P1) and its carbazole derivatives (P2–P4) have been prepared with good yield by Suzuki coupling polymerization. P2 is an alternating copolymer based on fluorene and carbazole; P3 is a hyperbranched polymer with carbazole derivative as the core and polyfluorene as the long arms; P4 is a hyperbranched polymer with carbazole derivative as the core and the alternating fluorene and carbazole as the long arms. These polymers show highly thermal stability, and their structures and physical properties are studied using gel permeation chromatography, 1H NMR, 13C NMR, elemental analysis, Fourier transform infrared spectroscopy, thermogravimetry, UV–vis absorption, photoluminescence, and cyclic voltammetry (CV). The influence of the incorporation of carbazole and the hyperbranched structures on the thermal, electrochemical, and electroluminescent properties has been investigated. Both carbazole addition and the hyperbranched structure increase the thermal and photoluminescent stability. The CV shows an increase of the HOMO energy levels for the derivatives, compared with polyfluorene homopolymer (P1). The EL devices fabricated by these polymers exhibit pure blue‐light‐emitting with negligible low‐energy emission bands, indicating that the hyperbranched structure has a strong effect on the PLED characteristics. The results imply that incorporating carbazole into polyfluorene to form a hyperbranched structure is an efficient way to obtain highly stable blue‐light‐emitting conjugated polymers, and it is possible to adjust the property of light‐emitting polymers by the amount of carbazole derivative incorporated into the polymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 790–802, 2008
Polymerization ofo‐quinodimethanes. V. Ionic polymerization ofo‐quinodimethanes generated by thermal isomerization of corresponding benzocyclobutenes
Authors: Chino Keisuke , Endo Takeshi 
Published: December 2007

AbstractThe ionic polymerization of substitutedo‐quinodimethanes via thermal isomerization of benzocyclobutenes is described. In the cationic polymerizations of 1‐methoxy‐o‐quinodimethane in the presence of various cationic initiators at 110 °C for 12 h, chain transfer reactions also considerably underwent besides the polymerization. Meanwhile, cationic polymerizations of 1‐trimethylsilyloxy‐o‐quinodimethane under the same conditions gave good yields of the corresponding polymer. Anionic polymerizations of 1‐cyano‐o‐quinodimethane in the presence of anionic initiators such asn‐BuLi ort‐BuOK were performed at various temperatures for 12 h. Good yields of hexane‐insoluble polymer, which was produced by anionic polymerization of correspondingo‐quinodimethane as an intermediate, were obtained above 120 °C. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 844–850, 2008
Chiral discrimination of α‐amino acids by DNA tetranucleotides under electrospray ionization conditions
Authors: Sivaleela T. , Kumar M. Ravi , Prabhakar S. , Bhaskar G. , Vairamani M. 
Published: December 2007

AbstractA set of DNA tetranucleotides, which are 3′‐ or 5′‐end extended versions of GCA, was used as chiral selectors for the discrimination of enantiomers of α‐amino acids. The [X+Y–2H]2− ions of the 1:1 complexes were generated by electrospraying a mixture of tetranucleotide (X) and amino acid (Y) solution. Chiral discrimination was achieved by studying the collision‐induced dissociation spectra of the [X+Y–2H]2− ion and the ratio of relative abundance of precursor ion to that of the product ion was used to measure the extent of discrimination. Among the tetranucleotides used, GCAA and GGCA exhibited better discrimination, in which GCAA showed D‐selectivity and GGCA showed L‐selectivity for the studied amino acids. In addition, binding constants were measured for the 1:1 complexes of phenylalanine enantiomers with GCAA and GGCA. Copyright © 2007 John Wiley & Sons, Ltd.
A new in vitro approach for the simultaneous determination of phase I and phase II enzymatic activities of human hepatocyte preparations
Authors: Lahoz Agustín , Donato Maria Teresa , Montero Sandra , Castell José V. , Gómez‐Lechón Maria José 
Published: December 2007

AbstractPrimary hepatocytes are still the best qualified in vitro system to anticipate drug metabolism in man. Recent advances in hepatocytes cryopreservation have notably increased their use not only for drug metabolism studies, but also for other applications such as cell transplantation. Evaluation of the drug‐metabolizing competence of each hepatocytes preparation is needed. To date, the metabolic characterization of hepatocytes preparations relies on the assessment of phase I activities and the role of phase II enzymes receives little attention. A novel approach for the rapid assessment of the metabolic functionality of hepatocytes has been developed. A five‐probe cocktail was used to simultaneously determine the enzymatic activities of major human phase I CYPs (CYP1A2, CYP2A6, CYP2C9, CYP2E1, CYP3A4), as well as two phase II enzymes: glucuronidase (UGTs) and sulfotransferase (SULT). Liquid chromatography/tandem mass spectrometry was used as the technique of choice for the determination of the enzymatic activities in a single run. Results showed that the method described herein permits a rapid assessment of the metabolic capabilities of human hepatocyte preparations as well as an estimation of the quality of freshly isolated or cryopreserved hepatocytes. Copyright © 2007 John Wiley & Sons, Ltd.
Root causes of unsatisfactory performance of large and complex remediation projects: Lessons learned from the united states department of energy environmental management programs
Authors: Greenberg Michael , Powers Charles , Mayer Henry , Kosson David 
Published: December 2007

AbstractThe Consortium for Risk Evaluation with Stakeholder Participation (CRESP) was asked by the United States Department of Energy (US DOE) to consider the root causes of remediation projects that fail to entirely achieve their goals and then to offer suggestions to assist the Department. To begin this project, CRESP held several meetings at which the group defined problematic outcomes, the early symptoms of problematic outcomes, and the root causes of failing to meet expectations. The five root causes are complex science, engineering, and technology; ambiguous economics; project management shortcomings; political processes and credibility; and history and organizational culture. This article, while focusing on the US DOE, provides a larger context for many remediation projects that have failed to entirely live up to their sponsors' expectations. © 2007 Wiley Periodicals, Inc.
Zinc and cobalt phytoextraction by different plant species
Authors: Abdel‐Sabour M. F. , Al‐Salama Y. J. 
Published: December 2007

AbstractPlant species sorghum (Sorghum vulgar L.), clover (Trifolium pratense L.), panikum (Panicum antidotal), and canola (Brassica napus) were tested to determine their phytoremediation potential. After a period of about 90 days, plant samples (shoots and roots) and soil samples (before and after cultivation) were collected for zinc and cobalt analyses using atomic absorption spectrometry. The highest zinc uptake was observed in canola, while panikum grass showed a high zinc accumulation affinity compared to sorghum and clover. Calculation of the recovery percentage, based on the amount of zinc removed from the soil after cultivation, ranged between 12.8 and 36.3 percent of the total initial zinc. Canola shoots exhibited the highest cobalt uptake compared to the other plant species. Calculation of the recovery percentage based on cobalt removed from the soil after cultivation ranged between 10.1 and 40.7 percent of the total initial cobalt concentration. © 2007 Wiley Periodicals, Inc.*This article is a U.S. Government work and, as such, is in the public domain of the United States of America.
Estimating survival in newly diagnosed cancer patients: Use of computer simulations to evaluate performances of different approaches in a wide range of scenarios
Authors: Rashid Ivan , Marcheselli Luigi , Federico Massimo 
Published: December 2007

AbstractMany empirical studies have proven the usefulness of period analysis in providing more up‐to‐date estimates of cancer patient survival than cohort‐based methods. The aim of this paper is to provide a non‐empirical evaluation of several survival approaches over a comprehensive range of scenarios using computer simulations. The simulation model included the following input parameters: number of annual patients, length of survival calculation, number of years of diagnosis, prognosis of cancer, follow‐up period, and two additional parameters for modeling assumption on incidence and survival trends. The current study also introduced alternative cohort‐ and period‐based approaches in addition to more traditional methods. Simulations showed that the choice of an appropriate survival approach is strongly dependent on the given scenario: period analysis was effective only for a limited number of circumstances, while alternative approaches appeared to be suitable for more realistic situations, when the follow‐up period is different from the incidence period. The results of simulations could be useful for a quick identification of the most appropriate approach when estimating up‐to‐date cancer survival rates. Copyright © 2007 John Wiley & Sons, Ltd.
The origin of life in comets
Authors: Napier W.M. , Wickramasinghe J.T. , Wickramasinghe N.C. 
Published: December 2007

AbstractMechanisms of interstellar panspermia have recently been identified whereby life, wherever it has originated, will disperse throughout the habitable zone of the Galaxy within a few billion years. This re-opens the question of where life originated. The interiors of comets, during their aqueous phase, seem to provide environments no less favourable for the origin of life than that of the early Earth. Their combined mass throughout the Galaxy overwhelms that of suitable terrestrial environments by about 20 powers of ten, while the lifetimes of friendly prebiotic environments within them exceeds that of localized terrestrial regions by another four or five powers of ten. We propose that the totality of comets around G-dwarf Sun-like stars offers an incomparably more probable setting for the origin of life than any that was available on the early Earth.
Mislocalization of human transcription factor MOK2 in the presence of pathogenic mutations of lamin A/C
Authors: Dreuillet Caroline , Harper Maryannick , Tillit Jeanne , Kress Michel , Ernoult‐Lange Michèle 
Published: December 2007

Background information. hsMOK2 (human MOK2) is a DNA‐binding transcriptional repressor. For example, it represses the IRBP (interphotoreceptor retinoid‐binding protein) gene by competing with the CRX (cone‐rod homeobox protein) transcriptional activator for DNA binding. Previous studies have shown an interaction between hsMOK2 and nuclear lamin A/C. This interaction could be important to explain hsMOK2 ability to repress transcription.Results. In the present study, we have tested whether missense pathogenic mutations of lamin A/C, which are located in the hsMOK2‐binding domain, could affect the interaction with hsMOK2. We find that none of the tested mutations is able to disrupt hsMOK2 binding in vitro or in vivo. However, we observe an aberrant cellular localization of hsMOK2 into nuclear aggregates when pathogenic lamin A/C mutant proteins are expressed.Conclusions. These results indicate that pathogenic mutations in lamin A/C lead to sequestration of hsMOK2 into nuclear aggregates, which may deregulate MOK2 target genes.
Structure and sequence of the Cu, Zn superoxide dismutase gene of Chymomyza amoena: phylogeny of the genus and codon‐use evolution
Authors: Kwiatowski J. , Skarecky D. , Burgos M. , Ayala F. J. 
Published: December 2007

AbstractWe have cloned and sequenced the Cu, Zn superoxide dismutase gene of Chymomyza amoena. The coding sequence has the same length as in Drosophila species and in Ceratitis capitata. There are two introns, located at the same sites as in Ceratitis. The second intron is absent in Drosophila: this places Chymomyza outside the Drosophila lineage, contrary to proposals based on anatomical and other evidence. The nucleotide or amino acid distances support a phylogeny in which Ceratitis first branches off the common stem, then Chymomyza splits before the divergence of the two major Drosophila subgenera. The estimated divergence times are 58 million for Chymomyza‐Drosophila; 48 million years for the Drosophila subgenera. During the intervening 10 million years, the Drosophila lineage lost the second intron and evolved distinct codon‐preferences: the G + C use in the third coding positions is increased by 69% in Drosophila relative to Chymomyza or Ceratitis.
Intrapopulation nestclusters of maternal mtDNA lineages in the polygynous ant Leptothorax acervorum (Hymenoptera: Formicidae)
Authors: Stille M. , Stille B. 
Published: December 2007

AbstractAnalysis of restriction fragment length polymorphism (RFLP) in mitochondrial DNA (mtDNA) in a population of Leptothorax acervorum demonstrates substantial population substructuring. Digestion with four restriction endonucleases, Haelll, Mbol, Mspl and Rsal, gave six, four, three and two different patterns, respectively. Seven composite haplotypes were obtained from the observed cleavage patterns. Uniform aggregations of nests from the same maternal lineage (i. e. with the same haplotype) were found which suggests that nestfounding by a process of budding‐off is common. Groups of nests seem to actively exclude other haplotypes from establishing nests within their territory. Fstatistics suggests that individuals mate at random within the population.
PCR with arbitrary primers: approach with care
Authors: Black W. C. 
Published: December 2007

AbstractNew techniques have recently been described that employ the polymerase chain reaction (PCR) to amplify arbitrary regions of a genome using a single primer. The techniques reveal polymorphisms in insect taxa that lack allozyme variation and, for the first time, permit genetic polymorphisms to be rapidly analysed in small arthropods (e.g. mites, endoparasitic wasps). The methods have been used in identification of sub‐species and cryptic species, and have applications in population genetics and genetic fingerprinting. They are fairly inexpensive, do not require the use of radioactivity, are relatively simple to learn and can easily be adapted to most laboratories. However, their application is not without technical problems and practical limitations. The purpose of this note is to indicate the critical factors to consider before launching into their use. We chiefly emphasize that most polymorphisms revealed by these methods segregate as dominant markers. Furthermore, application of these techniques requires extensive standardization and may not prove to be reproducible among various laboratories especially those employing different types of thermal cyclers. There are some unique features of these polymorphisms to consider when using them in genetic fingerprinting. In addition, because the techniques amplify arbitrary regions of genomes, similarly sized fragments amplified between two species may not be homologous. This argument and empirical observations suggest that PCR with arbitrary primers will have limited application in molecular systematics above the intraspecific level.
A centromeric satellite DNA of the unisexual Bacillus atticus (Insecta: Phasmatodea)
Authors: Mantovani B. , Batistoni R. , Nardi I. , Scali V. 
Published: December 2007

AbstractIn the parthenogenetic Bacillus atticus atticus, widespread over most of the Mediterranean basin, a highly repeated satellite DNA (BaB300) has been detected and analysed. Bgl II, Taq I and Alu I restriction enzymes cut 316 bp long repeating units from the BaB300 family. These are non‐coding, AT rich and well conserved in the three isolated populations studied. By in situ hybridization, the satellite has been located in the centromeric heterochromatin of a subset of medium‐and small‐sized chromosomes, including the Xs. Related sequences have been found in the bisexual B. grandii grandii and in its specific hybrid B. whitei (=B. rossius/grandii grandii), while they are absent from B. rossius redtenbacheri. These data support the genetic affinity relationships within the genus Bacillus inferred from morphological, allozymic and karyological data. They also encourage further comparisons among Bacillus hybrids, in order to trace their parental genomes in the hybrid nuclei, and within the B. atticus complex (i.e. additional samples of B. a. atticus and diploid/triploid cytotypes of B. a. carius) to study repetitive DNA turnover in unisexual organisms.
A cytoplasmic actin gene from the silkworm Bombyx mo/7 is expressed in tissues of endodermal origin and previtellogenic germ cells of transgenic Drosophila
Authors: Horard B. , Bello B. , Abraham E. G. , Coulon‐Bublex M. , Garel A. , Mounier N. 
Published: December 2007

AbstractA cytoplasmic actin gene from Bombyx mori introduced into Drosophila melanogaster by P‐element mediated transformation, is efficiently transcribed in larvae, pupae and adults of the host. The exogenous mRNA has the same size as the one observed in the Bombyx cells and the intron located within the coding region is properly excised, indicating a correct recognition of the exogenous sequences by the Drosophila transcriptional and splicing machineries. The expression of the Bombyx gene in Drosophila tissues was determined by transforming flies with a hybrid gene in which a large part of the Bombyx actin coding sequences was replaced by those of the bacterial lac Z gene. This chimaeric gene is specifically and highly expressed, from the embryo to the adult of the transgenic lines, in tissues of endodermal origin, the midgut and its derivatives, i.e. gastric caeca, the outer layer of the proventriculus, and in the Malpighian tubules. This gene is also expressed, at a lower level, in germ cells but restricted to the sixteen cell cysts during previtel‐logenesis. The expression of the Bombyx gene during development of transgenic flies was compared to that of the two Drosophila endogenous cytoplasmic actin genes and the results are discussed.
Molecular taxonomy using single‐strand conformation polymorphism (SSCP) analysis of mitochondrial ribosomal DNA genes
Authors: Hiss R. H. , Norris D. E. , Dietrich C. H. , Whitcomb R. F. , West D. F. , Bosio C. F. , Kambhampati S. , Piesman J. , Antolin M. F. , IV W. C. Black 
Published: December 2007

AbstractSingle‐strand conformation polymorphism (SSCP) analysis detects single point mutations in DNA molecules. We demonstrate that SSCP analysis of mitochondrial ribosomal DNA (rDNA) genes is a sensitive taxonomic tool because these genes often differ at numerous sites among closely related species. Using conserved primers, portions of the 12S or 16S rDNA genes were amplified using the polymerase chain reaction (PCR) in congeneric species of ticks, leaf hoppers, mosquitoes, and closely related endoparasitic wasps. SSCP was performed and products were visualized with silver staining. Species‐specific patterns were observed in all taxa. Intraspecific variation at the level of single nucleotide substitutions was detected. SSCP diagnostics are less expensive and time consuming to develop than PCR with species‐specific primers, and, unlike PCR with arbitrary primers, there is minimal concern with DNA contamination from non‐target organisms.
High‐level expression of the bacterial opd gene in Drosophila melanogasten improved inducible insecticide resistance
Authors: Benedict M. Q. , Scott J. A. , Cockburn A. F. 
Published: December 2007

AbstractThe bacterial parathion hydrolase gene (opd) was expressed in transformed D. melanogaster under the control of an hsp70 promoter. Transformed lines carrying chimaeric genes designed for either cytoplasmic or secretory expression exhibited high‐ or low‐level heat‐shock‐inducible transient resistance to paraoxon respectively. Greatest levels of resistance occurred approximately 12–16 h after heat shock and well after periods of maximal transcription. Insecticide resistance conferred by the cytoplasmic form of opd is expressed as a semidominant trait.
Molecular polymorphism as a tool for differentiating ground beetles (Carabus species): application of ubiquitin PCR/SSCP analysis
Authors: Boge A. , Gerstmeier R. , Einspanier R. 
Published: December 2007

AbstractDifferentiation between Carabus species (ground beetle) and subspecies is difficult, although there have been extensive studies. To address this problem we have applied PCR in combination with SSCP analysis focussing on the evolutionally conservative ubiquitin gene to elaborate a new approach to molecular differentiation between species. We report that Carabidae possess an ubiquitin gene and that its gene has a multimeric structure. Differential SSCP analysis was performed with the monomeric form of the gene to generate a clear SSCP pattern. Such PCR/SSCP resulted in reproducible patterns throughout our experiments. Comparing different Carabus species (Carabus granulatus, C. irregularis, C. violaceus and C. auronitens) we could observe clear interspecies differences but no differences between genders. Some species showed some remarkable differences between the individuals. We suggest that the ubiquitin PCR‐SSCP technique might be an additional tool for the differentiation of ground beetles.
Isolation, cloning and deduced amino acid sequence of a novel glycoprotein from the haemolymph of the hawkmoth Manduca sexta
Authors: Samaraweera P. , Law J. H. 
Published: December 2007

AbstractA low‐abundance haemolymph protein from adult male Manduca sexta was purified to homogeneity. The 29,000 Da glycoprotein is synthesized in the fat body, is present in both male and female, and is present during all stages of development. Antiserum against the 29 kDa protein was raised in a rabbit and used to screen an M. sexta larval fat body cDNA library. An 880 base pair clone was isolated and found to contain the full‐length transcript. Sequencing of the cDNA revealed an open reading frame of 699 bases beginning from the possible translation initiation site. The deduced 233‐amino acid polypeptide contains an apparent 17‐amino acid signal peptide and three potential N‐glycosylation sites. The function of the 29 kDa protein is unknown.