bluuebunny/crossref_metadata_2025 huggingface dataset:
Fibrous component of the blastocoelic extracellular matrix shapes epithelia in concert with mesenchyme cells in starfish embryos
Authors: Kaneko Hiroyuki , Okai Murasaki , Murabe Naoyuki , Shimizu Takahiko , Ikegami Susumu , Dan‐Sohkawa Marina
Published: February 2005

By using a monoclonal antibody (4H11 Mab), we have investigated morphogenetic functions of a fibrous component of the blastocoelic extracellular matrix in relation to cellular activities during early development of the starfish Asterina pectinifera. The 4H11 fibers fill the blastocoele from the late‐cleavage to late‐gastrula stage and contain the 370‐kDa proteinaceous molecule secreted only by the epithelial cells. When 4H11 Mab is introduced into the blastocoele of blastulae, the embryos reveal three distinct morphological abnormalities after the mid‐gastrula stage: (1) Distribution of mesenchyme cells confined near the tip of the archenteron, (2) swelling of the posterior ectoderm, and (3) suppressed growth of the mouth, esophagus, and coelomic pouches. These abnormalities occur together with alterations in the distribution of the 4H11 fibers. In embryos recovering from the effect of 4H11 Mab, the mesenchyme cells rearrange the 4H11 fibers. We propose that 4H11 fibers play direct roles in the morphogenesis of starfish embryos by providing a dynamic scaffold not only for the mesenchyme cells but also for the epithelial cells. Moreover, 4H11 fibers have a resist force from within, in concert with the mesenchyme cells, to counter the bulging force intrinsic to the epithelia and hold the epithelia in specific positions, once the positions have been decided. Developmental Dynamics 232:915–927, 2005. © 2005 Wiley‐Liss, Inc.
Genomic, cDNA, and embryonic expression analysis of zebrafish transforming growth factor beta 3 (tgfβ3)
Authors: Cheah Felicia S.H. , Jabs Ethylin Wang , Chong Samuel S.
Published: February 2005

TGFβ3, a member of the transforming growth factor β family, regulates a spectrum of biological processes and is involved in mammalian pulmonary and craniofacial development. Homologs of human TGFβ3 have been identified in several vertebrate species. We sequenced a cDNA clone of zebrafish tgfβ3, consisting of a 271‐bp 5′ untranslated region, a 1,233‐bp open reading frame that encodes a predicted 410 amino acid peptide, and a 527‐bp 3′ untranslated region. Using 5′ rapid amplification of cDNA ends, the transcription start site of this gene was determined to lie an additional 29 nucleotides upstream. The gene is composed of seven exons and maps to a segment of linkage group 17 that is syntenic to the human TGFβ3 locus on chromosome 14q24. One stimulating protein 1 (Sp1) and two (TATA binding protein) (TBP) transcription factor binding sites were identified in the putative promoter segment upstream of the transcription start site. Comparative alignment analysis revealed a high degree of tgfβ3 nucleotide and amino acid identity between zebrafish and other species, including complete conservation of the cysteine knot structure that facilitates protein–protein interaction. Also, 9 of 10 amino acid residues critical for ligand/receptor binding in human TGFβ3 are conserved in zebrafish, suggesting a high degree of functional conservation even in lower vertebrates. Zebrafish tgfβ3 transcripts were first detected in the notochord (10 somite to high‐pec stage), followed by expression in the developing pharyngeal arch and neurocranial cartilage (18 somite to protruding mouth stage), lens and heart (21 somite to protruding mouth stage), and pectoral fins (prim‐25 to protruding mouth stage). The strong expression in the pectoral fins, not reported in the orthologous mammalian forelimb, suggests a modified or novel function of tgfβ3 during early fish development. Developmental Dynamics 232:1021–1030, 2005. © 2005 Wiley‐Liss, Inc.
DNA methyltransferase expression in the mouse germ line during periods of de novo methylation
Authors: Lees‐Murdock Diane J. , Shovlin Tanya C. , Gardiner Tom , De Felici Massimo , Walsh Colum P.
Published: February 2005

DNA methyltransferase (DNMT) 3A and DNMT3B are both active de novo DNA methyltransferases required for development, whereas DNMT3L, which has no demonstrable methyltransferase activity, is required for methylation of imprinted genes in the oocyte. We show here that different mechanisms are used to restrict access by these proteins to their targets during germ cell development. Transcriptional control of the Dnmt3l promoter guarantees that message is low or absent except during periods of de novo activity. Use of an alternative promoter at the Dnmt3a locus produces the shorter Dnmt3a2 transcript in the germ line and postimplantation embryo only, whereas alternative splicing of the Dnmt3b transcript ensures that Dnmt3b1 is absent in the male prospermatogonia. Control of subcellular protein localization is a common theme for DNMT3A and DNMT3B, as proteins were seen in the nucleus only when methylation was occurring. These mechanisms converge to ensure that the only time that functional products from each locus are present in the germ cell nuclei is around embryonic day 17.5 in males and after birth in the growing oocytes in females. Developmental Dynamics 232:992–1002, 2005. © 2005 Wiley‐Liss, Inc.
Genomic resources for chicken
Authors: Antin Parker B. , Konieczka Jay H.
Published: February 2005

The recent sequencing and draft assembly of a chicken genome has provided biologists with an invaluable research tool that complements a growing list of additional avian genomic resources. For many researchers, finding and using these resources is challenging, because information is presented through an increasing number of Web sites and browser navigation frequently requires specific knowledge and expertise. This primer provides an overview of online genomic resources for the chicken, including the Ensembl, UCSC, and NCBI annotated chicken genome browsers; expressed sequence tag and in situ hybridization databases; and sources for microarrays, cDNAs, and bacterial artificial chromosomes (BACs). Several short tutorials oriented toward the biologist with limited bioinformatics skills outline how to retrieve several types of commonly needed information and reagents. Developmental Dynamics 232:877–882, 2005. © 2005 Wiley‐Liss, Inc.
Magic number silicon dioxide‐based clusters: Laser ablation‐mass spectrometric and density functional theory studies
Authors: Kong Qingyu , Zhao Li , Wang Wenning , Wang Chen , Xu Can , Zhang Wingham , Liu Lei , Fan Kangnian , Li Yufen , Zhuang Jun
Published: February 2005

The magic number silica clusters [(SiO2)nO2H3]− with n = 4 and 8 have been observed in the XeCl excimer laser (308 nm) ablation of various porous siliceous materials. The structural origin of the magic number clusters has been studied by the density functional theoretical calculation at the B3LYP/6‐31G** level, with a genetic algorithm as a supplementary tool for global structure searching. The DFT results of the first magic number cluster are parallel to the corresponding Hartree–Fock results previously reported with only small differences in the structural parameters. Theoretical calculation predicts that the first magic number cluster (SiO2)4O2H4 and its anion [(SiO2)4O2H3]− will most probably take pseudotetrahedral cage‐like structures. To study the structural properties of the second magic number cluster, geometries of the bare cluster (SiO2)8, the neutral complex cluster (SiO2)8O2H4, and the anionic cluster [(SiO2)8O2H3]− are fully optimized at the B3LYP/6‐31G** level, and the corresponding vibrational frequencies are calculated. The DFT calculations predict that the ground state of the bare silica octamer (SiO2)8 has a linear chain structure, whereas the second magic number complex cluster (SiO2)8O2H4 and its anion [(SiO2)8O2H3]− are most probably a mixture of cubic cage‐like structural isomers with an O atom inside the cage and several quasi‐bicage isomers with high intercage interactions. The stabilization of these structures can also be attributed to the active participation of the group of atoms 2O and 4H (3H for the anion) in chemical bonding during cluster formation. Our theoretical calculation gives preliminary structural interpretation of the presence of the first and second magic number clusters and the absence of higher magic numbers. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 584–598, 2005
The OH• + CH3SH reaction: Support for an addition‐elimination mechanism from ab initio calculations
Authors: Muiño Pedro L.
Published: February 2005

Several intermediates for the CH3SH + OH• → CH3S• + H2O reaction were identified using MP2(full) 6‐311+g(2df,p) ab initio calculations. An adduct, CH3S(H)OH•, I, with electronic energy 13.63 kJ mol−1 lower than the reactants, and a transition state, II‡, located 5.14 kJ mol−1 above I, are identified as the entrance channel for an addition‐elimination reaction mechanism. After adding zero‐point and thermal energies, ΔH(reactants → I) = −4.85 kJ mol−1 and ΔH(I → II‡) = +0.10 kJ mol−1, which indicates that the potential energy surface is broad and flat near the transition state. The calculated imaginary vibrational frequency of the transition state, 62i cm−1, is also consistent with an addition–elimination mechanism. These calculations are consistent with experimental observations of the OH• + CH3SH reaction that favored an addition–elimination mechanism rather than direct hydrogen atom abstraction. An alternative reaction, CH3SH + OH• → CH3SOH + H•, with ΔH = +56.94 kJ mol−1 was also studied, leading to a determination of ΔH(CH3SOH) = −149.8 kJ mol−1. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 612–618, 2005
Three‐phase airlift internal loop reactor: correlations for predicting the main fluid dynamic parameters
Authors: Trilleros JA , Díaz R , Redondo P
Published: February 2005

Three‐phase airlift loop reactors have many industrial applications. Examples include applications in the chemical, metallurgical, biochemical and minerals‐processing industries; fluid dynamics in such systems is a critical factor affecting efficiency. The experimental work was carried out at a pilot‐plant scale in a tank with a cylindrical shape and conical bottom (height 1.25 m; diameter 0.42 m), water and air were used as liquid and gas phases, and for different solid phases, different loads of glass spheres (diameters: 0.25 and 1 mm; density 2.6 g cm−3), and polystyrene cylinders (diameter and length 3 mm; density 1.0 g cm−3) were introduced. Air was injected through the bottom of the tank by means of 12 nozzles (diameter 1 mm each). An internal draft tube riser was tested on different configurations as its diameter was varied (44, 82, 125 and 240 mm) as was its height (1050 and 630 mm). Corresponding liquid velocities in the adjacent annular downcomer were determined by a thermal tracer technique, solid holdups were determined by conductivity methods, riser overall gas holdups were deduced from the liquid level, and riser gas holdup from manometer readings. Several adjusted correlations were considered in a method to predict the main fluid dynamic parameters (solids and gas holdups, and superficial liquid velocities). Copyright © 2005 Society of Chemical Industry
Qualitative and quantitative analysis of active flavonoids in Flos Lonicerae by capillary zone electrophoresis coupled with solid‐phase extraction
Authors: Chen Jun , Li Song‐Lin , Li Ping , Song Yue , Chai Xing‐Yun , Ma Ding‐Yuan
Published: February 2005

Flavonoids are an important bioactive group in the commonly used herbal medicine Flos Lonicerae. A new method of capillary zone electrophoresis (CZE) coupled with solid‐phase extraction (SPE) was developed for simultaneous assay of flavonoid aglycones and glycosides in Flos Lonicerae. Optimum CZE separation was achieved with a background electrolyte (BGE) solution consisting of 80 mM boric acid and 20 mM phosphate acid, adjusted to pH 8.1, with 15% acetonitrile (v/v) added, and applying a separation voltage of 28 kV. The SPE method was used for pretreating the complex matrix of botanical materials and good reproducibility was obtained when avicularin was used as internal standard. Linearity of the method was excellent with correlation coefficients (r 2) in the range of 0.9995–0.9999 and detection limits were lower than 0.6 μg/mL for the four flavonoids. The obtained recoveries varied between 93 to 104% while the relative standard deviations (RSDs) were below 4.4% (n = 3). The developed CZE method was successfully used for the separation of eight flavonoids and the quantification of the four flavonoids in five species of Flos Lonicerae.
Optimization of microwave‐assisted extraction for alizarin and purpurin in Rubiaceae plants and its comparison with conventional extraction methods
Authors: Dabiri Minoo , Salimi Shabnam , Ghassempour Alireza , Rassouli Ali , Talebi Mohammad
Published: February 2005

A simple and rapid microwave‐assisted extraction (MAE) procedure was developed and optimized for two common color pigments, alizarin and purpurin, in various samples of Rubiaceae plants. Several variables that can potentially affect the extraction efficiency, namely temperature, methanol concentration in the extractant mixture, time, and solvent volume were optimized by means of a central composite design approach. The results suggest that temperature and methanol concentration in the solvent mixture are statistically the most significant factors. The separation and quantitative determination of the pigments was carried out in less than 6 min by a developed high‐performance liquid chromatographic method with UV detection at 250 nm. Under optimum operating conditions, MAE showed significantly higher recoveries than those obtained by the conventional extraction methods (ultrasonic and reflux extraction), ranging from 84 to 94%. In addition, a drastic reduction of the extraction time (20 min versus 6 h) and solvent consumption (20 versus 100 mL) was achieved with a reproducibility (RSDs < 10%) comparable with that provided by the reflux extraction as a reference method.
Statistical‐overlap theory for elliptical zones of high aspect ratio in comprehensive two‐dimensional separations
Authors: Davis Joe M.
Published: February 2005

The low prediction by statistical‐overlap theory of the numbers of singlets and peaks in two‐dimensional separations containing zones represented by either circles of small number or eccentric ellipses of any number is shown to result from use of probability expressions for unbound spaces of infinite extent. An exact theory is derived for the probability of singlet formation in a reduced two‐dimensional space of unit length, width, and area. The probability is a weighted sum of the probabilities of singlet formation in the interior, edge, and corner regions of the space, which depend only on saturation. The weighting factors are the fractions of area associated with each region and depend on the number of zones, the aspect ratio, the saturation, and the ellipse's spatial orientation. The average numbers of doublets, triplets, and peaks in the space are approximated by combining these results with Roach's equations describing the clustering of circles in an unbound two‐dimensional space. Simulations show that theory predicts the number of singlets, doublets, triplets, and peaks, when the number of zones is 25 or more, the aspect ratio is 100 or less, and the saturation is 2 or less. The relationship is derived between the aspect ratios of ellipses in the reduced space and actual separation space. Calculations are presented for comprehensive two‐dimensional gas chromatography.
Determination of organic acids in aerosol particles from a coniferous forest by liquid chromatography–mass spectrometry
Authors: Anttila Piia , Hyötyläinen Tuulia , Heikkilä Anu , Jussila Matti , Finell Johan , Kulmala Markku , Riekkola Marja‐Liisa
Published: February 2005

LC–MS methods with use of ion‐trap and time‐of‐flight mass spectrometers were developed for the determination of organic acids in aerosol samples collected by a high‐volume sampler in a Finnish coniferous forest. Comparison was made of the composition of samples collected during atmospheric formation of new aerosol particles and on days when this formation did not occur. A dynamic sonication‐assisted solvent extraction system was developed for fast and quantitative extraction of the filter samples. Several organic acids, including pinonic acid, pinic acid, and homologuous series of n‐alkanoic acids, n‐alkenoic acids, and aliphatic dicarboxylic acids, were identified. In samples collected between 08:00 and 16:00 hours the concentration of pinonic acid ranged from 0.5 ng m–3 to 3.7 ng m–3 and that of pinic acid from 0.2 ng m–3 to 1.5 ng m–3. For most of the compounds identified, the trends in concentration could be explained by the differences in temperature during collection. However, concentrations of short‐chain n‐alkanoic acids were clearly higher on the days when new aerosol particle formation occurred.
Size fractionation of marine sediments by pinched inlet gravitational split‐flow thin fractionation and the study of size dependent PCDD/Fs concentrations from different bay areas
Authors: Moon Myeong Hee , Kim Hyun‐Joo , Jung Young‐Ok , Lee Se‐Jin , Chang Yoon‐Seok
Published: February 2005

Pinched inlet gravitational split‐flow thin fractionation (PI‐GSF) has been applied to the continuous size fractionation of marine sediments in order to study the difference in sediment size distribution and the concentration of PCDD/Fs contained in different particle sizes. A PI‐GSF channel, known to improve the separation efficiency by reducing the sample inlet thickness, was utilized to fractionate sediments collected from three different bay areas (Geoje, Ulsan, and Pohang) in Korea into 5 different sub‐populations (< 2.0, 2.0–5.0, 5.0–10, 10–20, 20–63 μm in diameter). The sorted sediment fractions from PI‐GSF were examined using electron microscopy to obtain size distribution and the results showed a variation in particle size distribution between bay areas. When the collected particle fractions were examined for size dependent levels of PCDD/Fs, the concentrations of total PCDD/Fs were shown to be much greater for samples collected close to heavy industry complexes than sediments from bay areas without major industry.
Atom Transfer Radical Copolymerization of α‐Olefins with Methyl Acrylate: Determination of Activation Rate Parameters
Authors: Venkatesh Rajan , Vergouwen Frank , Klumperman Bert
Published: February 2005

Summary: The activation rate parameters of three model compounds for an acrylate/α‐olefin atom transfer radical copolymerization were investigated. It appeared that the activation of the model compound for the dormant acrylate chain (methyl‐2‐bromopropionate) was quite fast (kact = 0.018 (±0.001) L · mol−1 · s−1 at 0 °C). The activation of the model compound for the dormant α‐olefin chain end (2‐bromobutane) did not take place at any appreciable rate (0 and 35 °C). The introduction of a penultimate acrylate unit in the model compound for the dormant α‐olefin chain end (H‐MA‐hexene‐Br) did not result in any activation at 0 and 35 °C. Only at 70 °C some activation was visible after 18 h reaction time. By inference, these results confirm our earlier conclusion that the ATR copolymerization of acrylates and α‐olefins is possible due to the fast crosspropagation of an α‐olefin chain end radical with an acrylate.

1H NMR spectra for the MBrP/Cu(I)Br/PMDETA/hydroxy TEMPO (1/10/10/10) mixture.

magnified image

1H NMR spectra for the MBrP/Cu(I)Br/PMDETA/hydroxy TEMPO (1/10/10/10) mixture.
Cover Picture: Macromol. Rapid Commun. 5/2005
Authors: Wong Wai‐Yeung , Wong Chun‐Kin , Poon Suk‐Yue , Lee Albert W.‐M. , Mo Tian , Wei Xin
Published: February 2005

Cover: The cover picture shows the molecular architecture and the absorption and emission spectra of a novel rod‐like polyyne polymer comprised of an electron‐rich platinum framework and an electron‐accepting silole unit that features an alternating donor‐π‐acceptor (D‐π‐A) type structural motif. This polymer exhibits a very low band gap and interesting optoelectronic properties.

Further details can be found in the Communication by W.‐Y. Wong,* C.‐K. Wong, S.‐Y. Poon, A. W.‐M. Lee, T. Mo, and X. Wei on page 376.
Diagnosis and management of pergolide‐induced fibrosis
Authors: Hirani Naushad , Bayliff Charles C. , McCormack David G.
Published: February 2005

A reply to this letter has been published in Movement Disorders Mov Disord (2005) 20 (4) 513.
PA‐6 and EVA alloy/clay nanocomposites as char forming agents in poly(propylene) intumescent formulations
Authors: Tang Yong , Hu Yuan , Xiao Junfeng , Wang Jun , Song Lei , Fan Weicheng
Published: February 2005

This study investigates the influence of nylon‐6 (PA‐6) and ethylene‐vinyl acetate copolymer (EVA) alloy/clay nanocomposites on the properties of the flame‐retardant (FR) poly(propylene). Cone calorimetry and scanning electron microscopy (SEM) techniques were used to investigate the effect of PA‐6 and EVA alloy nanocomposites on the fire properties and dispersion of intumescent flame‐retardants (IFRs). The experimental results show that PA‐6 and EVA alloy nanocomposites improve the fire and mechanical properties of the FR poly(propylene). It is also shown that the improvement of the properties mainly depends on the weight ratio of PA‐6 and EVA in the alloys. The probable mechanisms are discussed in this paper. Copyright © 2005 John Wiley & Sons, Ltd.
Holographic polymer‐dispersed liquid crystal fabrication under electric field
Authors: Shin Eui Young , Jung Ju Ai , Hee Kim Eun , Kim Byung Kyu
Published: February 2005

The transmission mode of holographic polymer‐dispersed liquid crystals (HPDLCs) was developed an under electric field. It is reported that orientation of LC molecules under an electric field induces orientation of oligomer molecules giving rise to low off‐state diffraction and small grating shrinkage. Copyright © 2005 Society of Chemical Industry
Effects of injection‐molding processing parameters on acetaldehyde generation and degradation of poly(ethylene terephthalate)
Authors: Shukla Shunahshep R , Lofgren Elizabeth A , Jabarin Saleh A
Published: February 2005

The acetaldehyde (AA) generation behavior of poly(ethylene terephthalate) (PET) has been investigated in terms of its relationship to changes in various processing conditions. A single‐cavity injection‐molding machine was used to prepare preforms in order to relate changes in barrel temperature, screw shear rate, back pressure, cooling time and total residence time to levels of AA generated during processing. Within the temperature range 280–300 °C, a 10 °C rise in processing temperature causes AA production to double. Shear rate increases from 20 to 40 m min−1 result in 13–21 % increases in AA generation at temperatures from 300 to 280 °C. Increased back pressures from 0 to 200 bar result in AA concentration increases of about 1.2 ppm for each 50 bar pressure increase. The majority of this change is caused by increased polymer residence time. Longer cooling times also increase overall cycle times and result in higher levels of AA generation, at the rate of almost 7 ppm per additional minute at 290 °C processing conditions. Apparent activation energies of 167 kJ mol−1 were calculated for samples prepared at various shear rates. These results are in agreement with literature values obtained under conditions of static mixing and indicate that shear rate and plastication do not significantly affect reaction mechanisms for AA generation. Copyright © 2005 Society of Chemical Industry
The effect of higher order RNA processes on changing patterns of protein domain selection: A developmentally regulated transcriptome of type 1 inositol 1,4,5‐trisphosphate receptors
Authors: Regan Melissa R. , Lin Doris D.M. , Emerick Mark C. , Agnew William S.
Published: February 2005

The domain structure of proteins synthesized from a single gene can be remodeled during tissue development by activities at the RNA level of gene expression. The impact of higher order RNA processing on changing patterns of protein domain selection may be explored by systematically profiling single‐gene transcriptomes. itpr1 is one of three mammalian genes encoding receptors for the second messenger inositol 1,4,5‐trisphosphate (InsP3). Some phenotypic variations of InsP3 receptors have been attributed to hetero‐oligomers of subunit isoforms from itpr1, itpr2, and itpr3. However, itpr1 itself is subject to alternative RNA splicing, with 7 sites of transcript variation, 6 within the ORF. We have identified 17 itpr1 subunit species expressed in mammalian brain in ensembles that change with tissue differentiation. Statistical analyses of populations comprising >1,300 full‐length clones suggest that subunit variation arises from a variably biased stochastic splicing mechanism. Surprisingly, the protein domains of this highly allosteric receptor appear to be assembled in a partially randomized way, yielding stochastic arrays of subunit species that form tetrameric complexes in single cells. Nevertheless, functional expression studies of selected subunits confirm that splicing regulation is connected to phenotypic variation. The potential for itpr1 subunits to form hetero‐tetramers in single cells suggests the expression of a developmentally regulated continuum of molecular forms that could display diverse properties, including incremental sensitivities to agonist activation and varying patterns of Ca2+ mobilization. These studies illuminate the extent to which itpr1 molecular phenotype is induced by higher order RNA processing. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Spatial variability in the mineralisation of the phenylurea herbicide linuron within a Danish agricultural field: multivariate correlation to simple soil parameters
Authors: Rasmussen Jim , Aamand Jens , Rosenberg Per , Jacobsen Ole S , Sørensen Sebastian R
Published: February 2005

The spatial variability in the mineralisation rate of linuron [N‐(3,4‐dichlorophenyl)‐N′‐methoxy‐N′‐methylurea] was studied within a previously treated Danish agricultural field by sampling soils from eleven different plots randomly distributed across an area of 20 × 20 m. The soils were characterised with respect to different abiotic and biotic properties including moisture content, organic matter content, pH, nutrient content, bacterial biomass, potential for mineralisation of MCPA [(4‐chloro‐2‐methylphenoxy)acetic acid] and linuron. Five soils had a potential for mineralisation of linuron, with 5–15% of the added [ring‐U‐14C]linuron metabolised to 14CO2 within 60 days at 10 °C, while no extensive mineralisation of linuron was observed in the six remaining soils within this period. A TLC analysis of the methanol‐extractable residues showed no development of 14C‐labelled metabolites from linuron in any of the samples. Multivariate analysis was conducted to elucidate relationships between the intrinsic properties of single soil samples and initial rate of linuron mineralisation. The analysis indicated that important soil parameters in determining the spatial heterogeneity included the Ctotal/Ntotal ratio, pH and the water‐extractable potassium contents, with the first of these highly negatively correlated and the last two highly positively correlated to the initial linuron mineralisation rate. This study shows that enhanced biodegradation of linuron may develop with successive field treatments, but that considerable in‐field spatial heterogeneity in the degradation rate still exists. Combined with a parallel enrichment study focused on the underlying microbial processes, the present results suggest that intrinsic soil properties affect the linuron‐metabolising bacterial population and thereby determine the spatial variability in the linuron mineralisation activity. Copyright © 2005 Society of Chemical Industry
Ionic conductivity and conductivity relaxation of potassium tellurite glasses
Authors: El‐Desoky M. M. , Ragab H. S.
Published: February 2005

The electrical conductivity and conductivity relaxation of xK2O–(100–x)TeO2 glasses have been investigation in the frequency range 40 Hz to 200 kHz and temperature range 300 to 473 K. From the density and molar volume, it may be noticed that with increasing K2O content the density decreases while the molar volume increases highlighting the fact that more nonbridging oxygens (NBOs) are formed in the network as the concentration of K2O is increased. The Anderson–Stuart model was employed to explain the dc activation energy. The frequency‐dependent electrical data have been analyzed in the framework of the conductivity and modulus formalisms. The decrease of the conductivity relaxation time with increasing content of K2O was explained in the framework of the structural model of tellurite glasses. The variation of the stretched exponential parameter β with composition was compared with those of lithium and sodium tellurite glasses and was explained in terms of cation–cation distance correlation. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Imprinting magnetic memory cells in molecular based NiL2(C2H5OH)2 heterospin crystals
Authors: Morgunov R. , Gudoshnikov S. , Ossypian Yu. , Ovcharenko V. , Sagdeev R. , Skomarovskii V. , Tanimoto Y.
Published: February 2005

The distribution of local magnetic fields near the surface of plastically deformed molecular based NiL2(C2H5OH)2 heterospin single crystals was studied by a scanning SQUID microscope. It was found that local deformation by indentation causes ferromagnetic exchange interaction in NiL2(C2H5OH)2 crystals at unusually high temperatures (≥77 K) in the area ∼104 µm2 near the indentation pit. This magnetization temperature is much higher than observed in the bulk of the undeformed crystal (∼5 K). An estimation shows that spin ordering could be concentrated around structural defects. It gives the possibility to make a premeditated imprinting having a magnetic structure and to distribute magnetic memory cells on a crystal surface. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Density functional studies on hydrogen‐bonded clusters of hydrogen halides and the interaction on halide anions
Authors: Nirmala V. , Kolandaivel P.
Published: February 2005

Density functional theory (DFT) calculations have been performed to study the structures and stability of X−·(HX)n=2–5clusters where X = F, Cl, Br at B3LYP/6‐311++G** level of theory. The presence of halide ions in these clusters disintegrates the hydrogen halide clusters. All the hydrogen halides are then hydrogen bonded to the centrally placed halide ions, thereby forming multiple hydrogen bonds. The interaction energies have been corrected for the basis set superposition error (BSSE) using Boy's counterpoise correction method. Evidence for the destruction of hydrogen bonds in hydrogen halide clusters due to the presence of halide ions is further obtained from topological analysis and natural bond orbital analysis. The chemical hardness and chemical potential have been calculated for all the anion clusters. The above analysis reveals that hydrogen bonding in these systems is not an essentially electrostatic interaction. The nature of the stabilization interactions operative in these multiple hydrogen‐bonded clusters has been explained in terms of many‐body contribution to interaction energies. From these studies, an attempt has been made to understand the nature of the molecular properties resulting from different electronegativities of the halogens. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Structure of charge‐transfer reaction complexes in anionic polymerization of isoprene: Quantum chemical calculations
Authors: Kalninsh K. K. , Podolsky A. F.
Published: February 2005

A new mechanism of isoprene anionic polymerization is proposed. Its central moment is thermal electronic excitation of a living polyisoprene–isoprene complex into the quasi‐degenerate electronically excited state (S · T)1, which is of the charge (electron) transfer character. It is asserted that the probability of chemical bond formation is determined by the free valence index on carbon atoms and by the geometry of reacting complex in the excited state (S · T)1. Semi‐empirical AM1 and ab initio 6‐31G* quantum chemical calculations revealed low energies of triplet excited levels (<10 kcal/mole). Comparison of isoprene polymerization on free anions and on solvated ion pairs shows that both types of active centers produce vinyl 1,2 (4,3)‐units. Free anions generate predominantly 1,2‐units, whereas solvated ion pairs tend to form units with the 4,3‐structure. Analysis of energies of excited isoprenyl lithium + isoprene complexes shows that the formation of 1,4 (4,1)‐cis‐polyisoprene in an inert media is most preferable. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Franck–Condon and Jahn–Teller effects in the E state of (CO) molecule. Resonance and preresonance Raman study in terms of time‐dependent density functional theory: New insight into an old story
Authors: Makowski Marcin , Pawlikowski Marek T.
Published: February 2005

Franck–Condon and Jahn–Teller effects in the E state of the croconate dianion are studied in terms of time‐dependent density functional theory (TD‐DFT) at the B3LYP/aug‐cc‐pVDZ and BP86/aug‐cc‐pVDZ levels. The results of these treatments are then used to discuss the empirical absorption, preresonance, and resonance Raman spectra associated with A → E transition in the croconate dianion. In agreement with the experiment, the computations done at the B3LYP/aug‐cc‐pVDZ level of approximation predict substantial Jahn–Teller and Franck–Condon activities of ν2 (a) = 607 cm−1 (ring‐breathing) and ν11 (e) = 526 cm−1 (ring‐bending) modes in the lowest‐energy E state of the croconate ion. The activities of the other e‐ and a‐symmetry modes were found to be quite modest. It is shown that the sizable activities of ν2 (a) and ν11 (e) modes lead to Bactrian‐like structure in the absorption corresponding to the A → E transition. Taking into account the consistencies between the electronic absorption and Raman experiments, we can convincingly argue that the double‐band shape experimentally observed in the absorption of the croconate dianion cannot be attributed to solute–solvent interactions, as was recently proposed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Triplet potential energy surface for BH2N: A DFT study
Authors: Zhang Jian‐Guo , Li Qian Shu , Zhang Shao‐Wen
Published: February 2005

The triplet potential energy surfaces (PES) for the isomerization and dissociation reactions of BH2N isomers was investigated using the DFT/B3LYP method of theory. Thirteen BH2N isomer species and two dissociated products were identified, in which five isomerization reactions and four dissociation pathways were found. On the triplet PES, the nonplanar trans‐iminoborane (1) can isomerize to the lowest triplet state of planar aminoboranylidene (3) and the triplet state planar borylnitrene (4) directly by two three‐membered ring transition states (TS1–3 and TS1–4), respectively. The cis‐trans isomerization of iminoborane (1 and 2) by transition state (TS1–2), the internal conversion of 1 and that of 2 by two transition states (TS1a–1b and TS2a–2b) are also considered in the triplet PES. On the other hand, the dissociation product of B–N–H (5) and H atom can be predicted by the dissociation reaction of nonplanar cis‐iminoborane (2) and a planar structure aminoboranylidene (3) with the transition state of TS2–5 and TS3–5. At the same time, the dissociation product H–B–N (6) and H atom can be predicted by the dissociation reaction of nonplanar cis‐iminoborane (2) and a planar structure borylnitrene (4) with the transition state of TS2–6 and TS4–6. By analysis of the whole potential energy surface, we can find the isomerization from planar the triplet state aminoboranylidene (3) to the triplet state planar borylnitrene (4) is not carried out in one step directly, but achieved in multistep reactions of (3)(1)(4). © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Coupled‐cluster study of the equilibrium geometry and harmonic vibrational frequencies of the methyl radical
Authors: Roberto‐Neto Orlando , Chakravorty Subhas , Machado Francisco B.C.
Published: February 2005

Accurate equilibrium geometries, harmonic vibrational frequencies, and equilibrium rotational constants of the methyl radical were computed using coupled‐cluster theory in combination with the cc‐pVnZ and cc‐pCVnZ basis sets of Dunning. Valence and all electron calculations were carried out. Using all electron correlations and CBS extrapolation, the re value is equal to 1.0758 Å, which is 0.0032 Å shorter than the experimental value of r0 (1.079 Å). The harmonic (ω1, ω2, ω3, and ω4) frequencies calculated using the CBS extrapolation differ from the experimental fundamental frequencies, respectively, by +142, +125, +21, and –82 cm−1. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Analysis of N7‐(benzo[a]pyrene‐6‐yl)guanine in urine using two‐step solid‐phase extraction and isotope dilution with liquid chromatography/tandem mass spectrometry
Authors: Chen Yi‐Lung , Wang Chien‐Jen , Wu Kuen‐Yuh
Published: February 2005

Analysis of urinary N7‐(benzo[a]pyren‐6‐yl)guanine (BP‐6‐N7Gua), a DNA adduct induced by benzo[a]pyrene, may serve as a risk‐associated biomarker for exposure to polyaromatic hydrocarbons (PAHs). In this study a highly sensitive and specific analytical method, incorporating on‐line sample preparation coupled with isotope‐dilution liquid chromatography and tandem mass spectrometry (LC/MS/MS), was developed to quantitate this adduct in human urine. In order to achieve accurate quantitation, 15N5‐labeled BP‐6‐N7Gua was synthesized to serve as the internal standard, and a two‐step solid‐phase extraction (SPE) procedure using C8 and SCX cartridges was used for sample cleanup. BP‐6‐7‐N7Gua was analyzed using positive ion LC/MS/MS operated in multiple reaction monitoring (MRM) mode. The [M+H]+ ions at m/z 402 and 407 and the common fragment ion of [M+H]+ at m/z 252 were monitored for quantification. The recovery of this analyte after two‐step SPE was 90%, and the limit of detection was 2.5 fmol/mL in 10 mL of urine. This highly specific and sensitive method for BP‐6‐N7Gua in urine may be applied to assess exposure to PAHs in coke‐oven workers for future molecular epidemiology studies on health effects of PAHs. Copyright © 2005 John Wiley & Sons, Ltd.
Creation of highly functional thin films using electrochemical nanotechnology
Authors: Osaka Tetsuya
Published: February 2005

This overview describes the results of our recent study of the application of electrochemical nanotechnology to the fabrication of magnetic recording materials, interconnects in ultra‐large‐scale integrated (ULSI) devices, energy storage materials, and on‐chip biosensors. It is important to note that electrochemical processes play significant roles in developing and fabrication such sophisticated materials and devices. In the field of magnetic recording, electrodeposition methods for preparing CoNiFe and CoFe soft magnetic thin films with a high saturation magnetic flux density were newly developed, and the significant issues for obtaining those films are highlighted. In the area of ULSI interconnects, we developed a technique using a self‐assembled monolayer (SAM) for direct bonding of the interconnect layer to SiO2, and proposed a novel electroless deposition method for fabricating a diffusion barrier layer. In the field of batteries, electrodeposited SnNi alloy was proposed as a future anode material for Li batteries, and electrochemical MEMS processes were shown to be useful for fabricating micro‐sized direct methanol fuel cells (DMFCs) as portable batteries for electronics applications. In the area of chemical sensors, we developed a new process for fabricating field effect transistors (FETs) modified with SAMs for on‐chip biosensing applications. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 346–362; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20025
Ultrafast dynamics of a solution in spatially restricted environments studied by photothermal spectroscopies
Authors: Hirose Yasushi , Yui Hiroharu , Sawada Tsuguo
Published: February 2005

The ultrafast dynamics of a solution in spatially restricted environments was studied by using the ultrafast transient lens (UTL) method. The UTL method is used to monitor the molecular dynamics of a solution by means of a change in the refractive index, which is advantageous for investigating the molecular dynamics of restricted systems. We investigated the photoisomerization of azobenzene derivatives in cyclodextrin nanocavities and revealed how the confinement affects the photoisomerization dynamics and yields. We also studied the relaxation dynamics of photo‐excited auramine O (AuO) in a water/aerosol‐OT/n‐heptane reversed micelle. Both the perturbed properties of the included water and the interactions between AuO and the interface of the reversed micelle strongly appeared to affect the relaxation dynamics. At the same time, we observed a change in the refractive index suggesting a structural change of the micelles in the picosecond region that could not be detected by transient absorption spectroscopy. In addition, we developed the total internal reflection UTL (TIR‐UTL) method to monitor the ultrafast molecular dynamics at the liquid interface. The relaxation dynamics of photoexcited AuO at the silica/water interface were observed with subpicosecond time resolution, and it was revealed that the interaction with the interface strongly inhibited the relaxation process. These results demonstrated the advantages of the UTL method for investigating the molecular dynamics of a solution in spatially restricted environments. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 331–345; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20026
1‐alkoxyvinyl esters: renaissance of half‐century‐old acyl donors with potential applicability
Authors: Kita Yasuyuki , Akai Shuji
Published: February 2005

Among the various kinds of acyl donors, the 1‐alkoxyvinyl esters have characteristic features, such as a high reactivity under nearly neutral conditions and the generation of neutral and volatile esters as single coproducts. Although their use in organic syntheses began in the middle of the 1950s, no significant progress has been seen. This is probably because the existing method of preparing alkoxyvinyl esters used toxic mercuric salts and was not totally applicable for those esters having functionalized acyl moieties.

We have discovered that the use of a catalytic amount of the less toxic [RuCl2(p‐cymene)]2 effectively accelerates the addition of carboxylic acids to ethoxyacetylene to give ethoxyvinyl esters bearing a variety of functionalized acyl groups in high yields. This discovery has opened a new avenue for developing new reactions and new synthetic methodologies based on the design and use of these acyl donors with suitable functional groups. Such examples include (i) the installation of hydrophilic acyl moieties on biologically active compounds, (ii) asymmetric Pummerer‐type reactions, (iii) aromatic Pummerer‐type reactions, (iv) the lipase‐catalyzed desymmetrization of symmetrical 1,3‐diols, and (v) lipase‐catalyzed domino reactions. Future possibilities for these acyl donors are also discussed. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 363–372; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20027
Geochemical evidence for rapid enlargement of a gentoo penguin colony on Barton Peninsula in the maritime Antarctic
Authors: ZHU RENBIN , SUN LIGUANG , YIN XUEBIN , XIE ZHOUQING , LIU XIAODONG
Published: February 2005

Gentoo penguin Pygoscelis papua is an important component of the Antarctic marine ecosystem. In this paper, we use an indirect approach, a geochemical method combining with 137Cs and 210Pb CRS mode dating, to study the dynamics of the gentoo population and colony on Barton Peninsula, King George Island, in the maritime Antarctic. Five sediment profiles were sampled in the zone between the gentoo penguin colony and tundra vegetation on this peninsula and the sediment sequence and typical elements from penguin guano were analysed. Results showed that the levels for typical elements display a dramatic change at around 5 cm depth, indicating the strong impact of penguin guano. The sediments below 5 cm showed lower concentrations in these elements, suggesting that these sediments had received little impact from penguin guano. By Q-mode factor analysis, a method for decomposing multiple factors, we found that over the past sixty years the gentoo colony showed a rapid enlargement and the tundra vegetation had been destroyed. Possible factors responsible for the enlargement of the penguin colony are tentatively discussed.
The thermophilic bryoflora of Deception Island: unique plant communities as a criterion for designating an Antarctic Specially Protected Area
Authors: SMITH R.I. LEWIS
Published: February 2005

Deception Island in the South Shetland Islands is one of the most volcanically active sites south of 60°S. Between 1967 and 1970 three major eruptions devastated large expanses of the landscape and its vegetation. Since 1970 extensive recolonization has occurred on the more stable surfaces. Unheated ground supports several bryophyte and lichen communities typical of much of the Maritime Antarctic, but geothermal habitats possess remarkable associations of bryophytes, many of which are unknown or very rare elsewhere in the Antarctic. Nine geothermal sites and their vegetation are described. Communities associated with more transient sites have disappeared when the geothermal activity ceased. Mosses and liverworts occur to within a few centimetres of the vents where temperatures reach 90–95°C, while temperatures within adjacent moss turf can reach 35–50°C or more and remain consistently between 25 and 45°C. Most of the bryoflora has a Patagonian–Fuegian provenance. It is presumed that, unlike most species, the thermophiles are not pre-adapted to the Antarctic environment, being able to colonize only where the warm and humid conditions prevail. The floristic and ecological importance of these thermophilic communities, and their sensitivity to perturbation by the rapidly increasing annual summer influx of tourists, as well as scientists, has resulted in these unique sites being proposed as components of a new Antarctic Specially Protected Area under the Antarctic Treaty.
Air and permafrost temperatures at Mount Melbourne (1989–98)
Authors: GAMBINO SALVATORE
Published: February 2005

Recent meteorological studies suggest a mixed pattern of climate change in Antarctica: a general cooling of the interior continent and warming in the Antarctic Peninsula over the past several decades (e.g. Comiso 2000, Doran et al. 2002, Vaughan et al. 2003). This note presents 10 years of continuous recording of air and permafrost temperature at Mount Melbourne (74°21′S, 164°42′E) in Northern Victoria Land. Mount Melbourne is a quiescent volcano belonging to a wide-spread volcanic belt which has developed since the Oligocene along the western margin of the Ross Sea, parallel to the Transantarctic Mountains (Fig. 1a). In 1988 a tilt network composed of five continuous recording sensors each equipped with four temperature sensors (Fig. 1b) was installed within the framework of Italian PRNA between the end of 1988 and the beginning of 1989 (Bonaccorso et al. 1995).