bluuebunny/crossref_metadata_2025_split huggingface dataset:
C5H4BR2 Bending in Ferrocenylboranes: A Delocalized Through‐Space Interaction Between Iron and Boron
Authors: Scheibitz Matthias , Bolte Michael , Bats Jan W. , Lerner H.‐Wolfram , Nowik Israel , Herber Rolfe H. , Krapp Andreas , Lein Matthias , Holthausen Max C. , Wagner Matthias 
Published: December 2004

AbstractA comparison of the molecular structures of mono‐, di‐ and tetraborylated ferrocenes [Fc{B(R1)(R2)}] (R1/R2=Br/Br, Br/Fc, Br/Me, Me/Me, Me/OH, OMe/OMe), 1,1′‐[fc{B(R1)(R2)}2] (R1/R2=Br/Br, Br/Me, OMe/OMe), and 1,1′,3,3′‐[Fe{C5H3(BMe2)2}2] revealed the boryl substituent(s) to be bent out of the Cp ring plane towards the iron center. The corresponding dip angle α* decreases with decreasing Lewis acidity of the boron atom and with increasing degree of borylation at the ferrocene core. This trend is well reproduced by DFT calculations (including [FcBH2], not yet accessible experimentally). A Bader analysis of the electron density topology of [FcBH2] (α*=26.5°; BP86/TZVP) clearly showed that there is no direct iron–boron bonding in this compound. Instead, strongly delocalized orbital interactions have been identified that involve the boron p orbital, Cipso of the adjacent Cp ring, d orbitals at iron, and a through‐space interaction with the second Cp ring. A second important factor is attractive electrostatic interactions, which are enhanced upon ligand bending. Cyclic voltammetric measurements on the series [FcBMe2], 1,1′‐[fc(BMe2)2], and 1,1′,3,3′‐[Fe{C5H3(BMe2)2}2] indicate a substantial anodic shift in the oxidation potential of the central iron atom upon introduction of BMe2 substituents. Addition of 4‐dimethylaminopyridine (DMAP) does not just counterbalance this effect, but leads to a cathodic shift of the FeII/FeIII redox transition far beyond the half‐wave potential of parent ferrocene. In the Mössbauer spectra, a continuous decrease in the quadrupole splitting (QS) is observed upon going from parent ferrocene to [FcBMe2], to 1,1′‐[fc(BMe2)2], and to 1,1′,3,3′‐[Fe{C5H3(BMe2)2}2]. In contrast, no significant differences are found between the QS values of ferrocene, [Fc(BMe2DMAP)], and 1,1′‐[fc(BMe2−DMAP)2].
Roles of JUMONJI in mouse embryonic development
Authors: Jung Jooyoung , Mysliwiec Matthew R. , Lee Youngsook 
Published: December 2004

AbstractCardiac development is a complex biological process requiring the integration of cell specification, differentiation, migration, proliferation, and morphogenesis. Although significant progress has been made recently in understanding the molecular basis of cardiac development, mechanisms of transcriptional control of cardiac development remain largely unknown. In search for the developmentally important genes, the jumonji gene (jmj) was identified by gene trap technology and characterized as a critical nuclear factor for mouse embryonic development. Jmj has been shown to play important roles in cardiovascular development, neural tube fusion process, hematopoiesis, and liver development in mouse embryos. The amino acid sequence of the JUMONJI protein (JMJ) reveals that JMJ belongs to the AT‐rich interaction domain transcription factor family and more recently has been described as a member of the JMJ transcription factor family. Here, we review the roles of jmj in multiple organ development with a focus on cardiovascular development in mice. Developmental Dynamics 232:21–32, 2005. © 2004 Wiley‐Liss, Inc.
Genome‐wide identification of female‐enriched genes in zebrafish
Authors: Wen Chaoming , Zhang Zhenhai , Ma Weiping , Xu Min , Wen Zilong , Peng Jinrong 
Published: December 2004

AbstractCharacteristic differences in morphology, physiology, and behavior between a male and female are correlated to the differential selection of sex‐dependent transcriptomes. By using a cDNA array carrying ∼9,000 zebrafish unique genes, we identified a group of genes whose expression are enriched in the female fish. A subset of these genes have been confirmed and further grouped as egg‐enriched genes, as both somatic‐ and egg‐enriched genes or as somatic‐enriched genes by means of RNA gel blot hybridization. Most importantly, a significant proportion of these genes are either functionally unknown or are novel genes. Thus, future studies of this group of genes will help us greatly to understand more about sex‐determination and sex‐related physiology and behavior. In addition, comparison of zebrafish female‐enriched genes with that in Drosophila, we found that only germline genes are shared between vertebrate and invertebrate, suggesting that the process of oogenesis is highly conserved during the evolution. Developmental Dynamics 232:171–179, 2005. © 2004 Wiley‐Liss, Inc.
Peripheral blood fibrocytes contribute to the formation of the avian spleen
Authors: Nagy Nándor , Bíró Éva , Takács Ágnes , Pólos Miklós , Magyar Attila , Oláh Imre 
Published: December 2004

AbstractChick–quail chimeric studies were made to determine the origin of the cells of splenic ellipsoid. The ellipsoid is formed by supporting and phagocytic cells, which are embedded in a well‐organized extracellular matrix. Splenic and bursal anlage of 6‐ to 6.5‐day‐old quail embryos were transplanted into the coelomic cavity of 3‐day‐old chick embryos and further incubated for 17 days. CD45+ chicken hemopoietic cells colonized both organs. They formed the cells of the ellipsoid and the periellipsoidal white pulp of the transplanted quail spleen. Chicken‐specific collagen III was produced only in the donor quail spleen, but not in the bursa of Fabricius. The CD45+/collagen I+/collagen III+ cells are probably identical with the mammalian peripheral blood fibrocytes and contribute to the formation of supporting cells, whereas the CD45+/74.2+ ellipsoid‐associated macrophages are of monocytic origin. We provide, for the first time, experimental evidence that peripheral blood fibrocytes exist in the avian species; they are present in the circulation of the chicken embryo and contribute to the organogenesis of the spleen. Developmental Dynamics 232:55–66, 2005. © 2004 Wiley‐Liss, Inc.
Regulation of iro3 expression in the zebrafish spinal cord
Authors: Lewis Katharine E. , Bates Jennifer , Eisen Judith S. 
Published: December 2004

AbstractSpecification of spinal cord neurons is regulated by several different transcription factors. In this study, we analyze expression and regulation of the transcription factor iro3 in zebrafish spinal cord. In addition to its broad expression in the progenitor domain of intermediate spinal cord, iro3 is also expressed in postmitotic ventral neurons, starting at early somitogenesis stages. Initially, this expression is only in two primary motoneurons, CaP and VaP, but by 24 hr postfertilization, iro3 is expressed by all classes of zebrafish spinal motoneurons as well as by a ventral interneuron called VeLD. iro3 expression in the progenitor domain of intermediate spinal cord is regulated independently from its expression in ventral neurons. Hedgehog (Hh) signaling is unnecessary for iro3 expression in intermediate spinal cord, but it is required to repress iro3 expression in the progenitor domain of ventral spinal cord. We also show that the basic helix‐loop‐helix transcription factor Olig2 is required for repression of iro3 expression in the progenitor domain of ventral spinal cord. We discuss our findings in the context of previous studies, suggesting that iro3 represses formation of motoneurons and promotes formation of interneurons. Developmental Dynamics 232:140–148, 2005. © 2004 Wiley‐Liss, Inc.
Turtle–chicken chimera: An experimental approach to understanding evolutionary innovation in the turtle
Authors: Nagashima Hiroshi , Uchida Katsuhisa , Yamamoto Keiko , Kuraku Shigehiro , Usuda Ryo , Kuratani Shigeru 
Published: December 2004

AbstractTurtles have a body plan unique among vertebrates in that their ribs have shifted topographically to a superficial layer of the body and the trunk muscles are greatly reduced. Identifying the developmental factors that cause this pattern would further our understanding of the evolutionary origin of the turtles. As the first step in addressing this question, we replaced newly developed epithelial somites of the chicken at the thoracic level with those of the Chinese soft‐shelled turtle Pelodiscus sinensis (P. sinensis somites into a chicken host) and observed the developmental patterning of the grafted somites in the chimera. The P. sinensis somites differentiated normally in the chicken embryonic environment into sclerotomes and dermomyotomes, and the myotomes differentiated further into the epaxial and hypaxial muscles with histological morphology similar to that of normal P. sinensis embryos and not to that of the chicken. Epaxial dermis also arose from the graft. Skeletal components, however, did not differentiate from the P. sinensis sclerotome, except for small fragments of cartilage associated with the host centrum and neural arches. We conclude that chicken and P. sinensis share the developmental programs necessary for the early differentiation of somites and that turtle‐specific traits in muscle patterning arise mainly through a cell‐autonomous developmental process in the somites per se. However, the mechanism for turtle‐specific cartilage patterning, including that of the ribs, is not supported by the chicken embryonic environment. Developmental Dynamics 232:149–161, 2005. © 2004 Wiley‐Liss, Inc.
Toll‐like receptor 6‐independent signaling by diacylated lipopeptides
Authors: Buwitt‐Beckmann Ute , Heine Holger , Wiesmüller Karl‐Heinz , Jung Günther , Brock Roland , Akira Shizuo , Ulmer Artur J. 
Published: December 2004

AbstractBacterial lipopeptides are strong immune modulators that activate early host responses after infection as well as initiating adjuvant effects on the adaptive immune system. These lipopeptides induce signaling in cells of the immune system through Toll‐like receptor 2 (TLR2)–TLR1 or TLR2–TLR6 heteromers. So far it has been thought that triacylated lipopeptides, such as the synthetic N‐palmitoyl‐S‐[2,3‐bis(palmitoyloxy)‐(2RS)‐propyl]‐(R)‐cysteine (Pam3)‐CSK4, signal through TLR2–TLR1 heteromers, whereas diacylated lipopeptides, like the macrophage‐activating lipopeptide from Mycoplasma fermentans (MALP2) or S‐[2,3‐bis(palmitoyloxy)‐(2RS)‐propyl]‐(R)‐cysteine (Pam2)‐CGNNDESNISFKEK, induce signaling through TLR2–TLR6 heteromers. Using new synthetic lipopeptide derivatives we addressed the contribution of the lipid and, in particular, the peptide moieties with respect to TLR2 heteromer usage. In contrast to the current model of receptor usage, not only triacylated lipopeptides, but also diacylated lipopeptides like Pam2CSK4 and the elongated MALP2 analog Pam2CGNNDESNISFKEK‐SK4 (MALP2‐SK4) induced B lymphocyte proliferation and TNF‐α secretion in macrophages in a TLR6‐independent manner as determined with cells from TLR6‐deficient mice. Our results indicate that both the lipid and the N‐terminal peptides of lipoproteins contribute to the specificity of recognition by TLR2 heteromers and are responsible for the ligand–receptor interaction on host cells.
Cryptopatches and isolated lymphoid follicles: dynamic lymphoid tissues dispensable for the generation of intraepithelial lymphocytes
Authors: Pabst Oliver , Herbrand Heike , Worbs Tim , Friedrichsen Michaela , Yan Sheng , Hoffmann Matthias W. , Körner Heiner , Bernhardt Günter , Pabst Reinhard , Förster Reinhold 
Published: December 2004

AbstractIn comparison to secondary lymphoid organs, gut‐associated lymphoid tissues such as isolated lymphoid follicles (ILF) and cryptopatches (CP) have been less intensively studied. To gain a better insight into processes regulating organization and function of these structures, which are believed to participate in immune responses and extrathymic T cell development, we characterized the lymphoid structures of the murine small intestine in more detail. The size and cellular composition of small intestinal lymphoid aggregations were analyzed in C57BL/6 and BALB/c wild‐type and lymphotoxin (LT)‐deficient mice, by flow cytometry, histology and automated multi‐color immunofluorescence microscopy evaluating large coherent areas of the intestine. These evaluations demonstrate that aggregated lymphoid structures in the small intestine vary in size and cellular composition, with a majority of structures not matching the current definitions of CP or ILF. Accordingly, significant variations depending on species, age and mouse strain were observed. Furthermore, small bowel transplantation revealed a rapid exchange of B but not T cells between host and grafted tissue. Moreover, LT‐deficient animals lack any intestinal lymphoid aggregations yet possess the complete panel of intraepithelial lymphocytes (IEL). In summary, our observations disclose intestinal lymphoid aggregations as dynamic structures with a great deal of inborn plasticity and demonstrate their dispensability for the generation of IEL.
A mass‐conserving Level‐Set method for modelling of multi‐phase flows
Authors: van der Pijl S. P. , Segal A. , Vuik C. , Wesseling P. 
Published: December 2004

AbstractA mass‐conserving Level‐Set method to model bubbly flows is presented. The method can handle high density‐ratio flows with complex interface topologies, such as flows with simultaneous occurrence of bubbles and droplets. Aspects taken into account are: a sharp front (density changes abruptly), arbitrarily shaped interfaces, surface tension, buoyancy and coalescence of droplets/bubbles. Attention is paid to mass‐conservation and integrity of the interface.The proposed computational method is a Level‐Set method, where a Volume‐of‐Fluid function is used to conserve mass when the interface is advected. The aim of the method is to combine the advantages of the Level‐Set and Volume‐of‐Fluid methods without the disadvantages. The flow is computed with a pressure correction method with the Marker‐and‐Cell scheme. Interface conditions are satisfied by means of the continuous surface force methodology and the jump in the density field is maintained similar to the ghost fluid method for incompressible flows. Copyright © 2005 John Wiley & Sons, Ltd.
Probability distributions, trading strategies and leverage: an application of Gaussian mixture models
Authors: Lindemann Andreas , Dunis Christian L. , Lisboa Paulo 
Published: December 2004

AbstractThe purpose of this paper is twofold. Firstly, to assess the merit of estimating probability density functions rather than level or classification estimations on a one‐day‐ahead forecasting task of the EUR/USD time series. This is implemented using a Gaussian mixture model neural network, benchmarking the results against standard forecasting models, namely a naïve model, a moving average convergence divergence technical model (MACD), an autoregressive moving average model (ARMA), a logistic regression model (LOGIT) and a multi‐layer perceptron network (MLP). Secondly, to examine the possibilities of improving the trading performance of those models with confirmation filters and leverage.While the benchmark models perform best without confirmation filters and leverage, the Gaussian mixture model outperforms all of the benchmarks when taking advantage of the possibilities offered by a combination of more sophisticated trading strategies and leverage. This might be due to the ability of the Gaussian mixture model to identify successfully trades with a high Sharpe ratio. Copyright © 2004 John Wiley & Sons, Ltd.
High‐throughput assay of rotenone in olive oil using atmospheric pressure chemical ionization tandem mass spectrometry
Authors: di Donna Leonardo , Grassi Giovanni , Mazzotti Fabio , Perri Enzo , Sindona Giovanni 
Published: December 2004

AbstractA high‐throughput method is presented for the determination of rotenone in contaminated matrices. The procedure involves atmospheric pressure chemical ionization tandem mass spectrometry with a triple‐quadrupole instrument and the use as internal standard of a cycloadduct derivative of rotenone itself. The method was applied to the evaluation of the decay of rotenone in olives and olive oil at various times after exposure to the contaminant. Copyright © 2004 John Wiley & Sons, Ltd.
Ticlopidine quantification in human plasma by high‐performance liquid chromatography coupled to electrospray tandem mass spectrometry. Application to bioequivalence study
Authors: Borges Ney Carter do Carmo , Mendes Gustavo Duarte , Borges André , Oliveira Sandro Evandir de , Barrientos‐Astigarraga Rafael Eliseo , Nucci Gilberto De 
Published: December 2004

AbstractA rapid, sensitive and specific method to quantify ticlopidine in human plasma using clopidogrel as the internal standard (IS) is described. The analyte and the IS were extracted from acidified plasma by liquid–liquid extraction using diethyl ether–hexane (80 : 20, v/v). The extracts were analyzed by high‐performance liquid chromatography coupled to electrospray tandem mass spectrometry (HPLC/MS/MS). Chromatography was performed isocratically on a Jones Genesis C84 µm analytical column (150 × 4.1 mm i.d.). The method had a chromatographic run time of 3.0 min and a linear calibration curve over the range 1.0–1000 ng ml−1(r2> 0.999427). The limit of quantification was 1.0 ng ml−1. This HPLC/MS/MS procedure was used to assess the bioequivalence of two ticlopidine 250 mg tablet formulations (ticlopidine test formulation from Apotex do Brasil, Brazil, and Ticlid from Sanofi‐Synthelabo, standard reference formulation). A single 250 mg dose of each formulation was administered to healthy volunteers. The study was conducted using an open, randomized, two‐period crossover design with a 2 week washout interval. Since the 90% confidence interval forCmaxand area under the curve ratios were all inside the 80–125% interval proposed by the US Food and Drug Administration, it was concluded that ticlopidine formulation from Apotex do Brasil is bioequivalent to Ticlid formulation with respect to both the rate and the extent of absorption. Copyright © 2004 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization mass spectrometry for the characterization of ionic liquids and the analysis of amino acids, peptides and proteins in ionic liquids
Authors: Zabet‐Moghaddam Masoud , Krüger Ralf , Heinzle Elmar , Tholey Andreas 
Published: December 2004

AbstractIonic liquids are interesting solvents for a number of applications in chemistry and biotechnology. We characterized five different ionic liquids by laser desorption/ionization (LDI) and by matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry (MS) and studied the analysis of amino acids, peptides and proteins dissolved in these solvents. Signals of both anions and cations of the ionic liquids could be observed both in LDI‐ and in MALDI‐MS. In the latter case, adduct formation between anions and cations of the analytes was observed. Amino acids, peptides and proteins could be analyzed in ionic liquids after addition of matrix substances. Sodium and potassium adducts were not observed in any analysis involving ionic liquids. Low molecular mass compounds and peptides could be analyzed best in the presence of water‐immiscible ionic liquids, whereas proteins gave the best results in water‐miscible ionic liquids. Optimal analysis conditions such as molar matrix‐to‐analyte and ionic liquid‐to‐matrix ratios were determined. Homogeneity of samples in the presence of ionic liquids was reduced compared with classical MALDI preparations. Relative quantitation of amino acids was possible using isotope‐labeled internal standards. MALDI‐MS thus can be used for the analysis of chemical reactions and the screening of enzyme‐catalyzed reactions in ionic liquids and for the analysis of the biocatalysts dissolved in these solvents. Theoretical aspects of ion formation in the presence of ionic liquids both in LDI and MALDI analysis are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of covalently inhibited extracellular lipase from Streptomyces rimosus by matrix‐assisted laser desorption/ionization time‐of‐flight and matrix‐assisted laser desorption/ionization quadrupole ion trap reflectron time‐of‐flight mass spectrometry: localization of the active site serine
Authors: Zehl Martin , Leščić Ivana , Abramić Marija , Rizzi Andreas , Kojić‐Prodić Biserka , Allmaier Günter 
Published: December 2004

AbstractA chemical modification approach combined with matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry was used to identify the active site serine residue of an extracellular lipase from Streptomyces rimosus R6‐554W. The lipase, purified from a high‐level overexpressing strain, was covalently modified by incubation with 3,4‐dichloroisocoumarin, a general mechanism‐based serine protease inhibitor. MALDI time‐of‐flight (TOF) mass spectrometry was used to probe the nature of the intact inhibitor‐modified lipase and to clarify the mechanism of lipase inhibition by 3,4‐dichloroisocoumarin. The stoichiometry of the inhibition reaction revealed that specifically one molecule of inhibitor was bound to the lipase. The MALDI matrix 2,6‐dihydroxyacetophenone facilitated the formation of highly abundant [M + 2H]2+ ions with good resolution compared to other matrices in a linear TOF instrument. This allowed the detection of two different inhibitor‐modified lipase species. Exact localization of the modified amino acid residue was accomplished by tryptic digestion followed by low‐energy collision‐induced dissociation peptide sequencing of the detected 2‐(carboxychloromethyl)benzoylated peptide by means of a MALDI quadrupole ion trap reflectron TOF instrument. The high sequence coverage obtained by this approach allowed the confirmation of the site specificity of the inhibition reaction and the unambiguous identification of the serine at position 10 as the nucleophilic amino acid residue in the active site of the enzyme. This result is in agreement with the previously obtained data from multiple sequence alignment of S. rimosus lipase with different esterases, which indicated that this enzyme exhibits a characteristic Gly‐Asp‐Ser‐(Leu) motif located close to the N‐terminus and is harboring the catalytically active serine residue. Therefore, this study experimentally proves the classification of the S. rimosus lipase as GDS(L) lipolytic enzyme. Copyright © 2004 John Wiley & Sons, Ltd.
Forecasting Australian drought using Southern Hemisphere modes of sea‐surface temperature variability
Authors: White Warren B. , Gershunov Alexander , Annis Jeffrey L. , McKeon Greg , Syktus Jozef 
Published: December 2004

AbstractDrought of 3 to 7 years' duration has devastated the flora, fauna, and regional economies in rangeland grazing districts over eastern and central Australia every 15 to 25 years throughout the 20th century, in some cases degrading the land beyond recovery. Recently, these drought and degradation episodes have been associated with a global interdecadal oscillation (IDO) of period 15 to 25 years. This IDO signal brought cooler sea‐surface temperatures (SSTs) to the western extra‐tropical South Pacific Ocean in association with reduced onshore transport of moisture over eastern/central Australia during the summer monsoon. Here, we utilize optimized canonical correlation analysis (CCA) to forecast principal components of summer precipitation (PCP) anomalies over Australia from the persistence of principal components that dominate spring SST anomalies across the Southern Hemisphere. These summer PCP forecasts are cross‐validated with the CCA forecast model for each year independent of that year's variability. Resulting cross‐validated forecasts are best over Queensland, correlating with those observed at >0.40 from 1890 through to 2001, significant at >99% confidence level. More importantly, 6 of 10 drought episodes (but only three of seven degradation episodes) observed in eastern/central Australia during the 20th century are forecast. Copyright © 2004 Royal Meteorological Society