bluuebunny/crossref_metadata_2025_split huggingface dataset:
Different Magnetic Properties for Diastereomers of Alkoxide-bridged (β-Diketonato)ruthenium(III) Binuclear Complexes
Authors: Hashimoto Takeshi , Kawamoto Yuji , Ishitobi Yousuke , Sasaki Tatsuya , Fukuda Yutaka , Yamagishi Akihiko , Sato Hisako , Shimizu Kunio , Hayashita Takashi 
Published: August 2007

Abstract
Symmetric alkoxide-bridged diruthenium complexes [{Ru(acac)2}2(μ-OMe)2], which are obtained when [Ru(acac)2(CH3CN)2] reacts in methanol, can be separated into two diastereomers by column chromatography, and these diastereomers are found to exhibit different magnetic properties despite their structural similarities.
Synthesis of polymers containing chiral 1,2-diamine derivatives and their application to asymmetric reactions
Authors: Itsuno Shinichi , Takahashi Miyuki , Arakawa Yukihiro , Haraguchi Naoki 
Published: August 2007

AbstractPolymer-supported chiral 1,2-diamine derivatives have been prepared. The polymers containing free 1,2-diamine moiety were applied to enantioselective hydrogenation catalyst by combination with RuCl2-BINAP complex. Asymmetric hydrogenation of aromatic ketones was performed by means of the polymeric catalyst derived from these polymers to give the chiral secondary alcohols with high ee in quantitative conversion. The polymers containing 1,2-diamine monosulfonamide were applied to enantioselective transfer hydrogenation catalyst by combination with RuCl2-p-cymene complex. Asymmetric transfer hydrogenation of aromatic ketones was performed by means of the polymeric catalyst to afford the chiral secondary alcohols. A high level of enantioselectivities up to 99 % ee was attained in neat water by using the polymeric catalyst prepared from quaternary ammonium salt-type polymer support.
Asymmetric allylic substitution of cycloalkenyl esters in water with an amphiphilic resin-supported chiral palladium complex
Authors: Uozumi Yasuhiro 
Published: August 2007

Abstract
A novel homochiral phosphine ligand, (3R,9aS)[2-aryl-3-(2-diphenylphosphino)phenyl]tetrahydro-1H-imidazo[1,5-a]indole-1-one, was designed, prepared, and anchored onto an amphiphilic polystyrene-poly(ethylene glycol) copolymer (PS-PEG) resin. Catalytic asymmetric substitution of a racemic mixture of cycloalkenyl esters with carbon, nitrogen, and oxygen nucleophiles was achieved in water as the single reaction medium under heterogeneous conditions by using the PS-PEG resin-supported palladium-imidazoindole phosphine complex to give optically active substituted cycloalkenes with up to 99 % ee.
Using macroporous N-chlorosulfonamide S/DVB copolymer as an aid to iron removal from water
Authors: Bogoczek Romuald , Kociołek-Balawejder Elżbieta , Stanisławska Ewa , Żabska Agnieszka 
Published: August 2007

Abstract
The de-ironing of water is a basic stage in water-treating technology. Consequently, the oxidation of easily soluble Fe(II) to poorly soluble Fe(III) compounds is indispensible. In order to oxidize Fe(II) ions to Fe(III), a macromolecular and macroporous product in bead form was used: polystyrene cross-linked by divinylbenzene, which contains pendant N-chlorosulfonamide groups in both the sodium and hydrogen forms. To assist the process of removing residual iron from water, this polymer - a macromolecular analog of Chloramine T, containing more than 4.0 mequiv of active chlorine/g - was prepared, starting from the sulfonate cation exchanger Amberlyst 15 by a three-step transformation of its functional groups. The investigations were carried out using both the batchwise and column methods, and 0.0025 M as well as 0.02 M FeSO4 solutions with different acidity were used. We found that the oxidation of ferrous ions to ferric by N-chlorosulfonamide copolymer was effective and was favored by a low pH. The oxidative ability of the copolymer was 225 mg Fe(II)/g. We established that the oxidation reaction could be operated in two directions. In acidic media (pH &lt; 2.5), Fe(III) ions remained in the solution as products of the reaction. The higher the pH, the more the poorly soluble ferric compounds sedimented in the inner structure of the copolymer beads. In this way, new hybrid materials were obtained, i.e., by ferrous/ferric oxides and hydroxides, by nanoparticles, modified materials which can serve as specific reacting sorbents and catalysts.
Synthesis and characterization of micrometer-sized molecularly imprinted spherical polymer particulates prepared via precipitation polymerization
Authors: Wang Jinfang , Cormack Peter A. G. , Sherrington David C. , Khoshdel Ezat 
Published: August 2007

Abstract
In this paper, the synthesis and characterization of molecularly imprinted spherical polymer particulates prepared via precipitation polymerization is described. The effects of the monomer and initiator concentrations and the solvent on the polymerizations were investigated systematically. Polymer microspheres with narrow size distributions and average diameters up to ca. 10 μm were prepared under optimized polymerization conditions. The morphologies of the microspheres were characterized by nitrogen sorption porosimetry and the molecular recognition properties of representative products evaluated in high-performance liquid chromatography (HPLC) mode. Imprinting effects were confirmed by analyzing the relative retentions of the analytes on imprinted and non-imprinted packed HPLC columns. Finally, two different agitation/mixing methods for precipitation polymerizations were compared. It was found that the use of a low-profile roller housed inside a temperature-controlled incubator had advantages over a rotavapor-based system. Overall, this study has served to highlight the attractiveness of precipitation polymerization for the routine production of molecularly imprinted polymers in a well-defined spherical particulate form via an efficient one-step synthetic process.
Biologically active polymeric sequestrants: Design, synthesis, and therapeutic applications
Authors: Dhal Pradeep K. , Huval Chad C. , Holmes-Farley S. Randall 
Published: August 2007

Abstract
In recent years, functional polymers exhibiting inherently biological activities have been receiving increasing attention as polymer-based human therapeutic agents. These polymeric drugs exhibit unique pharmaceutical properties that are fundamentally different from their traditional small-molecule counterparts. However, unlike polymeric drug delivery systems, examples of polymers possessing intrinsically therapeutic properties are relatively scarce. By virtue of their high-molecular-weight characteristics, these polymeric drugs can be confined to the gastrointestinal (GI) tract, where they can selectively recognize, bind, and remove target disease-causing substances from the body. Being confined to the GI tract and non-biodegradable, these polymeric drugs are free from toxic effects that are associated with traditional systemic drugs. This report highlights recent developments in the rational design and synthesis of appropriate functional polymers that have resulted in a number of promising polymer-based therapeutic agents, including some marketed products.
Self-supported chiral catalysts for heterogeneous enantioselective reactions
Authors: Ding Kuiling , Wang Zheng , Shi Lei 
Published: August 2007

Abstract
The development of a new strategy to immobilize the homogeneous chiral catalysts for enantioselective reactions is highly desirable in order to overcome some drawbacks of conventional approaches. In this lecture, a conceptually new strategy for heterogenization of homogeneous chiral catalysts (i.e., "self-supporting" approach) is presented. The concept focuses on the use of homochiral metal-organic coordination polymers generated by self-assembly of chiral multitopic ligands with metal ions as the heterogeneous catalysts, and thus obviating the need of any exogenous support. The application of this "self-supporting" strategy has been exemplified in heterogeneous catalysis of asymmetric carbonyl-ene, sulfoxidation, and epoxidation, as well as asymmetric hydrogenation reactions.
Future directions for the research and development of polyesters: From high-performance to environmentally friendly
Authors: Yamanaka Toru , Ohme Hiroyuki , Inoue Toshihide 
Published: August 2007

Abstract
We discuss the future directions for the research and development of polyester-based materials. In the discussion of polyesters as industrial materials, one direction is the development of high-performance materials. Poly(ethylene terephthalate) (PET), known as one of the most important polyesters, was developed early in the 1940s. We discuss two approaches to the development of high-performance materials suitable for injection-molding applications using PET units. The first approach is development of high-performance materials by copolymerization with bibenzoic acid (BB), which has a rigid structure, and the second approach is development of liquid-crystal polyesters (LCPs) with superior thermal resistance and excellent flowability using PET units. The other future direction for research and development is the targeting of environmentally friendly materials. Poly(lactic acid) (PLA), derived from bio-based materials, is a very important material because it can realize the carbon neutral cycles. Nevertheless, the practical properties of PLA itself are unsatisfactory compared to other plastics derived from fossil resources. We have developed PLA-based polymer alloys with various practical properties by utilizing a newly developed nanoalloy technology.
Highly active organosilane-based N-heterocyclic carbene-palladium complex immobilized on silica particles for the Suzuki reaction
Authors: Lee Sang-Myung , Yoon Hyo-Jin , Kim Jong-Ho , Chung Woo-Jae , Lee Yoon-Sik 
Published: August 2007

Abstract
1-Methyl-3-(3-trimethoxysilylpropyl)imidazolium chloride, [TMSPIM][Cl-], was synthesized as a precursor of N-heterocyclic carbene (NHC), which can be coordinated with palladium to give an organosilane-based bidentic NHC-Pd complex. The organosilane-based NHC-Pd complex was immobilized covalently on silica particles (NHC-Pd/silica) and then characterized by field emission/scanning electron microscopy (FE/SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIRS), and inductively coupled plasma/atomic emission spectroscopy (ICP/AES). The Suzuki reaction was performed as a model reaction to examine the catalytic activity of NHC-Pd/silica. NHC-Pd/silica exhibited excellent performance in the Suzuki reaction of various aryl halide derivatives (except for aryl chloride derivatives) with phenylboronic acid under mild conditions (room temperature and short reaction time). Moreover, the catalyst was recycled several times without any significant loss of catalytic activity in the Suzuki reaction.
Polysaccharide derivatives as useful chiral stationary phases in high-performance liquid chromatography
Authors: Chen Xiaoming , Yamamoto Chiyo , Okamoto Yoshio 
Published: August 2007

Abstract
The chromatographic separation of enantiomers using chiral stationary phases (CSPs) has significantly advanced. The esters and carbamates of polysaccharides coated on silica gel have been extensively studied and widely used as CSPs for high-performance liquid chromatography (HPLC). In order to overcome the strict solvent limitation on these coated CSPs, the preparation of a new generation of CSPs consisting of immobilized polysaccharide derivatives has become increasingly important. The universal solvent compatibility of the new CSPs provides flexibility in both analytical and preparative chromatographies.
Aggregation of biotinylated polymeric microspheres induced by interaction with avidin
Authors: Meng Qingbin , Li Zhanyong , Li Gang , Zhang Xu , An Yingli , Zhu X. X. 
Published: August 2007

Abstract
Monodisperse biotinylated poly(styrene-co-N-acryloxysuccinimide) microspheres were synthesized in aqueous solutions with a two-step method. Upon the addition of avidin solutions of different concentrations in phosphate buffer into the dispersed biotinylated microspheres, the microspheres aggregated rapidly due to the high binding affinity between biotin and avidin. The hydrodynamic diameter of the aggregates and the aggregation rate observed at given time intervals increased with increasing concentration of avidin. The composition of the microspheres and the incorporation of biotin were evidenced by Fourier transform infrared spectroscopy. The morphology, size distribution, and aggregation of the microspheres were studied by techniques such as scanning electron microscopy and dynamic light scattering.
Explanatory dictionary of key terms in toxicology (IUPAC Recommendations 2007)
Authors: Nordberg Monica , Duffus John H. , Templeton Douglas M. 
Published: August 2007

Abstract
The objective of the "Explanatory Dictionary of Key Terms in Toxicology" is to give full explanations of the meaning of toxicological terms chosen for their importance and complexity from the point of merging chemistry and toxicology. This requires a full description of the underlying concepts, going beyond a normal dictionary definition. Often linguistic barriers lead to problems in obtaining a common understanding of terminology at the international level and between disciplines. The explanatory comments should help to break down such barriers. The dictionary consists of about 68 terms chosen from the IUPAC "Glossary of Terms Used in Toxicokinetics" organized under 22 main headings. The authors hope that among the groups which will find this explanatory dictionary helpful are chemists, pharmacologists, toxicologists, risk assessors, regulators, medical practitioners, regulatory authorities, and everyone with an interest in the relationship of chemistry to toxicology. It should also facilitate the use of chemistry in relation to risk assessment.
Notes on Phase Extension
Authors: Frank Robert 
Published: August 2007

Abstract

1. The ingredients of locality

Since the early 1960s, one of the major goals of work in generative syntax has been to explain the locality properties of syntactic dependencies. Current accounts in the Minimalist framework derive locality from two basic notions. First, the syntactic relations that give rise to agreement and displacement are subjected to the Minimal Link Condition, which stipulates that such relations can obtain only in the absence of relevant intevening elements.
A ONECUT Homeodomain Protein Communicates X Chromosome Dose to SpecifyCaenorhabditis elegansSexual Fate by Repressing a Sex Switch Gene
Authors: Gladden John M , Meyer Barbara J 
Published: August 2007

AbstractSex is determined in Caenorhabditis elegans through a dose-dependent signal that communicates the number of X chromosomes relative to the ploidy, the number of sets of autosomes. The sex switch gene xol-1 is the direct molecular target of this X:A signal and integrates both X and autosomal components to determine sexual fate. X chromosome number is relayed by X signal elements (XSEs) that act cumulatively to repress xol-1 in XX animals, thereby inducing hermaphrodite fate. Ploidy is relayed by autosomal signal elements (ASEs), which counteract the single dose of XSEs in XO animals to activate xol-1 and induce the male fate. Our goal was to identify and characterize new XSEs and further analyze known XSEs to understand the principles by which a small difference in the concentration of an intracellular signal is amplified to induce dramatically different developmental fates. We identified a new XSE, the ONECUT homeodomain protein CEH-39, and showed that it acts as a dose-dependent repressor of xol-1 transcript levels. Unexpectedly, most other XSEs also repress xol-1 predominantly, but not exclusively, at the transcript level. The twofold difference in X dose between XO and XX animals is translated into the male vs. hermaphrodite fate by the synergistic action of multiple, independent XSEs that render xol-1 active or inactive, primarily through transcriptional regulation.
Patterns of Sequence Variability and Divergence at the diminutive Gene Region of Drosophila melanogaster: Complex Patterns Suggest an Ancestral Selective Sweep
Authors: Jensen Jeffrey D , Bauer DuMont Vanessa L , Ashmore Adeline B , Gutierrez Angela , Aquadro Charles F 
Published: August 2007

Abstract
To identify putatively swept regions of the Drosophila melanogaster genome, we performed a microsatellite screen spanning a 260-kb region of the X chromosome in populations from Zimbabwe, Ecuador, the United States, and China. Among the regions identified by this screen as showing a complex pattern of reduced heterozygosity and a skewed frequency spectrum was the gene diminutive (dm). To investigate the microsatellite findings, nucleotide sequence polymorphism data were generated in populations from both China and Zimbabwe spanning a 25-kb region and encompassing dm. Analysis of the sequence data reveals strongly reduced nucleotide variation across the entire gene region in both the non-African and the African populations, an extended haplotype pattern, and structured linkage disequilibrium, as well as a rejection of neutrality in favor of selection using a composite likelihood-ratio test. Additionally, unusual patterns of synonymous site evolution were observed at the second exon of this locus. On the basis of simulation studies as well as recently proposed methods for distinguishing between selection and nonequilibrium demography, we find that this “footprint” is best explained by a selective sweep in the ancestral population, the signal of which has been somewhat blurred via founder effects in the non-African samples.
Modulation ofCaenorhabditis elegansTranscription Factor Activity by HIM-8 and the Related Zinc-Finger ZIM Proteins
Authors: Sun Hongliu , Nelms Brian L , Sleiman Sama F , Chamberlin Helen M , Hanna-Rose Wendy 
Published: August 2007

AbstractThe previously reported negative regulatory activity of HIM-8 on the Sox protein EGL-13 is shared by the HIM-8-related ZIM proteins. Furthermore, mutation of HIM-8 can modulate the effects of substitution mutations in the DNA-binding domains of at least four other transcription factors, suggesting broad regulatory activity by HIM-8.
Functional Characterization of Pathogenic Human MSH2 Missense Mutations in Saccharomyces cerevisiae
Authors: Gammie Alison E , Erdeniz Naz , Beaver Julia , Devlin Barbara , Nanji Afshan , Rose Mark D 
Published: August 2007

Abstract
Hereditary nonpolyposis colorectal cancer (HNPCC) is associated with defects in DNA mismatch repair. Mutations in either hMSH2 or hMLH1 underlie the majority of HNPCC cases. Approximately 25% of annotated hMSH2 disease alleles are missense mutations, resulting in a single change out of 934 amino acids. We engineered 54 missense mutations in the cognate positions in yeast MSH2 and tested for function. Of the human alleles, 55% conferred strong defects, 8% displayed intermediate defects, and 38% showed no defects in mismatch repair assays. Fifty percent of the defective alleles resulted in decreased steady-state levels of the variant Msh2 protein, and 49% of the Msh2 variants lost crucial protein–protein interactions. Finally, nine positions are predicted to influence the mismatch recognition complex ATPase activity. In summary, the missense mutations leading to loss of mismatch repair defined important structure–function relationships and the molecular analysis revealed the nature of the deficiency for Msh2 variants expressed in the tumors. Of medical relevance are 15 human alleles annotated as pathogenic in public databases that conferred no obvious defects in mismatch repair assays. This analysis underscores the importance of functional characterization of missense alleles to ensure that they are the causative factor for disease.
Molecular Population Genetics of the Male and Female Mitochondrial DNA Molecules of the California Sea Mussel,Mytilus californianus
Authors: Ort Brian S , Pogson Grant H 
Published: August 2007

AbstractThe presence of two gender-associated mitochondrial genomes in marine mussels provides a unique opportunity to investigate the dynamics of mtDNA evolution without complications inherent in interspecific comparisons. Here, we assess the relative importance of selection, mutation, and differential constraint in shaping the patterns of polymorphism within and divergence between the male (M) and female (F) mitochondrial genomes of the California sea mussel, Mytilus californianus. Partial sequences were obtained from homologous regions of four genes (nad2, cox1, atp6, and nad5) totaling 2307 bp in length. The M and F mtDNA molecules of M. californianus exhibited extensive levels of nucleotide polymorphism and were more highly diverged than observed in other mytilids (overall Tamura–Nei distances &gt;40%). Consistent with previous studies, the M molecule had significantly higher levels of silent and replacement polymorphism relative to F. Both genomes possessed large numbers of singleton and low-frequency mutations that gave rise to significantly negative Tajima's D values. Mutation-rate scalars estimated for silent and replacement mutations were elevated in the M genome but were not sufficient to account for its higher level of polymorphism. McDonald–Kreitman tests were highly significant at all loci due to excess numbers of fixed replacement mutations between molecules. Strong purifying selection was evident in both genomes in keeping the majority of replacement mutations at low population frequencies but appeared to be slightly relaxed in M. Our results suggest that a reduction in selective constraint acting on the M genome remains the best explanation for its greater levels of polymorphism and faster rate of evolution.
Genomewide Identification of Genes Under Directional Selection: Gene TranscriptionQST Scan in Diverging Atlantic Salmon Subpopulations
Authors: Roberge C , Guderley H , Bernatchez L 
Published: August 2007

AbstractEvolutionary genomics has benefited from methods that allow identifying evolutionarily important genomic regions on a genomewide scale, including genome scans and QTL mapping. Recently, genomewide scanning by means of microarrays has permitted assessing gene transcription differences among species or populations. However, the identification of differentially transcribed genes does not in itself suffice to measure the role of selection in driving evolutionary changes in gene transcription. Here, we propose and apply a “transcriptome scan” approach to investigating the role of selection in shaping differential profiles of gene transcription among populations. We compared the genomewide transcription levels between two Atlantic salmon subpopulations that have been diverging for only six generations. Following assessment of normality and unimodality on a gene-per-gene basis, the additive genetic basis of gene transcription was estimated using the animal model. Gene transcription h2 estimates were significant for 1044 (16%) of all detected cDNA clones. In an approach analogous to that of genome scans, we used the distribution of the QST values estimated from intra- and intersubpopulation additive genetic components of the transcription profiles to identify 16 outlier genes (average QST estimate = 0.11) whose transcription levels are likely to have evolved under the influence of directional selection within six generations only. Overall, this study contributes both empirically and methodologically to the quantitative genetic exploration of gene transcription data.