bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proposed association between the COL1A1 and COL1A2 genes and otosclerosis is not supported by a case‐control study in Spain
Authors: Rodríguez Laura , Rodríguez Santiago , Hermida Juan , Frade Carlos , Sande Esther , Visedo Guillermo , Martín Carlos , Zapata Carlos 
Published: April 2004

AbstractOtosclerosis (OTSC) is one of the most common causes of hearing loss in white adults. The COL1A1 and COL1A2 genes coding for type‐I collagen have been proposed as candidate genes in the development of OTSC. The COL1A1 gene was recently reported to be associated with the condition on the basis of a population‐based case‐control study. We report here an independent study of association between COL1A1 and COL1A2 gene polymorphisms and OTSC, in a case‐control sample from a population of Caucasian individuals living in Northwest Spain. Specifically, we studied two COL1A1 polymorphisms previously reported to be associated with OTSC, and six COL1A2 polymorphisms. We performed diverse association analyses based on alleles, genotypes, and two‐locus haplotypes. We found no evidence supporting the putative link of COL1A1 and COL1A2 genes with OTSC. © 2004 Wiley‐Liss, Inc.
Identification of a new nonsense mutation (Tyr129Stop) of the SRY gene in a newborn infant with XY sex‐reversal
Authors: Giuffrè Mario , Sammarco Piero , Fabiano Carmelo , Giardina Fabio , Lunetta Fabio , Corsello Giovanni 
Published: April 2004

AbstractPoint mutations and deletions of SRY gene have been described in several cases of XY gonadal dysgenesis. To date, most of these mutations affect the HMG domain of SRY which plays a central role in DNA binding activity of SRY. We report on a non‐mosaic XY sex‐reversed newborn girl (completely female external genitalia). The direct sequencing of SRY showed a new nonsense mutation in a codon of SRY gene flanking the 3′ end of the HMG domain: a thymine is replaced by a guanine at position +387 in codon 129, resulting in the replacement of the amino acid tyrosine (TAT) by a stop codon (TAG). The new mutation of this patient provides further evidence to support the functional importance of the putative DNA binding activity of the HMG‐box domain. © 2004 Wiley‐Liss, Inc.
Hyperdeproteinized natural rubber prepared with urea
Authors: Klinklai Warunee , Saito Takayuki , Kawahara Seiichi , Tashiro Kei , Suzuki Yasuyuki , Sakdapipanich Jitladda Tangpakdee , Isono Yoshinobu 
Published: April 2004

AbstractPreparation of hyperdeproteinized natural rubber was made from fresh latex and preserved high‐ammonia latex by treatment with urea in the presence of sodium dodecyl sulfate. Concentration of urea, temperature, and time for the incubation were investigated to remove the proteins effectively. Under the best conditions, the total nitrogen content and amount of allergenic proteins for the deproteinized rubbers were 0.005 wt % and 1.0 μg/ml, respectively, which were less than those of natural rubber deproteinized with proteolytic enzyme. The hyper‐deproteinized natural rubber was proved through FT IR spectroscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 555–559, 2004
Examination of the time–water content superposition on the dynamic viscoelasticity of moistened polyamide 6 and epoxy
Authors: Ishisaka A. , Kawagoe M. 
Published: April 2004

AbstractWe have investigated the behavior of moisture absorption by the polyamide 6 and epoxy samples in various humid environments at constant temperature and also examined the effect of absorbed moisture on their dynamic viscoelastic properties. The moisture absorption was revealed to show the Fickian type of diffusion and to shift the dynamic viscoelastic properties of the specimen to those at lower temperature, as an effect of plasticization. Anti‐plasticization taken with an increase in the storage modulus was also observed in a low‐temperature range below −50°C. The time–water content superposition was confirmed to hold at various equilibrium water contents at constant temperature for both polyamide 6 and epoxy. The relation of the shift factor, log aH, to the equilibrium water content for polyamide 6 has a form similar to WLF equation of time–temperature superposition, whereas the log aH for epoxy does not have such a form. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 560–567, 2004
Magnetic field from spot welding equipment—is the basic restriction exceeded?
Authors: Nadeem Mohammad , Hamnerius Yngve , Mild Kjell Hansson , Persson Mikael 
Published: April 2004

AbstractA point measurement of the magnetic field (MF) near a typical spot welding machine showed that the magnetic flux density was above the ICNIRP reference level. To investigate if the basic restrictions were exceeded, the induced body currents in a full 3D human model were calculated. It was found that at an operator position of 34 cm away from the machine the maximum induced current density was below the ICNIRP basic restriction. But if the operator was closer to the machine, the basic restriction was exceeded. An important finding of the present article is that the basic restriction can be exceeded although the MF spatially averaged over the whole body is well below the reference level. Bioelectromagnetics 25:278–284, 2004. © 2004 Wiley‐Liss, Inc.
High frequency electromagnetic fields (GSM signals) affect gene expression levels in tumor suppressor p53‐deficient embryonic stem cells
Authors: Czyz Jaroslaw , Guan Kaomei , Zeng Qinghua , Nikolova Teodora , Meister Armin , Schönborn Frank , Schuderer Jürgen , Kuster Niels , Wobus Anna M. 
Published: April 2004

AbstractEffects of electromagnetic fields (EMF) simulating exposure to the Global System for Mobile Communications (GSM) signals were studied using pluripotent embryonic stem (ES) cells in vitro. Wild‐type ES cells and ES cells deficient for the tumor suppressor p53 were exposed to pulse modulated EMF at 1.71 GHz, lower end of the uplink band of GSM 1800, under standardized and controlled conditions, and transcripts of regulatory genes were analyzed during in vitro differentiation. Two dominant GSM modulation schemes (GSM‐217 and GSM‐Talk), which generate temporal changes between GSM‐Basic (active during talking phases) and GSM‐DTX (active during listening phases thus simulating a typical conversation), were applied to the cells at and below the basic safety limits for local exposures as defined for the general public by the International Commission on Nonionizing Radiation Protection (ICNIRP). GSM‐217 EMF induced a significant upregulation of mRNA levels of the heat shock protein, hsp70 of p53‐deficient ES cells differentiating in vitro, paralleled by a low and transient increase of c‐jun, c‐myc, and p21 levels in p53‐deficient, but not in wild‐type cells. No responses were observed in either cell type after EMF exposure to GSM‐Talk applied at similar slot‐averaged specific absorption rates (SAR), but at lower time‐averaged SAR values. Cardiac differentiation and cell cycle characteristics were not affected in embryonic stem and embryonic carcinoma cells after exposure to GSM‐217 EMF signals. Our data indicate that the genetic background determines cellular responses to GSM modulated EMF. Bioelectromagnetics 25:296–307, 2004. © 2004 Wiley‐Liss, Inc.
Lack of effect of 10 kV/m 60 Hz electric field exposure on pregnant dairy heifer hormones
Authors: Burchard J.F. , Nguyen D.H. , Monardes H.G. , Petitclerc D. 
Published: April 2004

AbstractSixteen pregnant Holstein heifers weighing 521 ± 46 kg, at 3.3 ± 0.7 months of gestation and 2.2 ±  2.0 months of age were confined to wooden metabolism cages and were exposed to a vertical electric field (EF) of 10.0 ± 0.4 kV/m and an artificial light cycle of 12 h light–12 h dark. The heifers were divided into two replicates of eight each. Each replicate was divided into two groups of four animals each, one group becoming the non‐exposed and the second, the EF exposed group. The exposed group were housed in metabolism cages in an area where EF were generated, and the non‐exposed group, in metabolism cages located in the adjacent area where the EF was less than 2% of that present in the exposed area. The test animals were subject to the different treatments for 4 weeks continuously. After 4 weeks, the animals switched treatment, the exposed group becoming the non‐exposed group and vice‐versa. Then the treatment continued for 4 more weeks. Catheters were inserted into the jugular vein of the animals, and blood samples were collected on twice a week to estimate the serum concentration of progesterone (P4), melatonin (MLT), prolactin (PRL), and insulin‐like growth factor‐1 (IGF‐1). Feed consumption was measured daily and feed samples were collected twice a week. The results indicated that exposure of dairy cattle to EF similar to those encountered directly underneath a 735 kV high tension electrical power line carrying a maximum load of current, cannot be associated with any variation in the experimental variables mentioned above. An exception to this, is the variation in MLT, which was associated with the EF exposure. Due to the inconsistency of the MLT response in the different replicates, caution should be exercised in the interpretation of this phenomenon. Bioelectromagnetics 25:308–312, 2004. © 2004 Wiley‐Liss, Inc.
Ion condensation and signal transduction
Authors: Ripoll Camille , Norris Vic , Thellier Michel 
Published: April 2004

AbstractMany abiotic and other signals are transduced in eukaryotic cells by changes in the level of free calcium via pumps, channels and stores. We suggest here that ion condensation should also be taken into account. Calcium, like other counterions, is condensed onto linear polymers at a critical value of the charge density. Such condensation resembles a phase transition and has a topological basis in that it is promoted by linear as opposed to spherical assemblies of charges. Condensed counterions are delocalised and can diffuse in the so‐called near region along the polymers. It is generally admitted that cytoskeletal filaments, proteins colocalised with these filaments, protein filaments distinct from cytoskeletal filaments, and filamentous assemblies of other macromolecules, constitute an intracellular macromolecular network. Here we draw attention to the fact that this network has physicochemical characteristics that enable counterion condensation. We then propose a model in which the feedback relationships between the condensation/decondensation of calcium and the activation of calcium‐dependent kinases and phosphatases control the charge density of the filaments of the intracellular macromolecular network. We show how condensation might help mediate free levels of calcium both locally and globally. In this model, calcium condensation/decondensation on the macromolecular network creates coherent patterns of protein phosphorylation that integrate signals. This leads us to hypothesize that the process of ion condensation operates in signal transduction, that it can have an integrative role and that the macromolecular network serves as an integrative receptor. BioEssays 26:549–557, 2004. © 2004 Wiley Periodicals, Inc.
Can flies help humans treat neurodegenerative diseases?
Authors: Marsh J. Lawrence , Thompson Leslie Michels 
Published: April 2004

AbstractNeurodegenerative diseases are becoming increasingly common as life expectancy increases. Recent years have seen tremendous progress in the identification of genes that cause these diseases. While mutations have been found and cellular processes defined that are altered in the disease state, the identification of treatments and cures has proven more elusive. The process of finding drugs and therapies to treat human diseases can be slow, expensive and frustrating. Can model organisms such as Drosophila speed the process of finding cures and treatments for human neurodegenerative diseases? We pose three questions, (1) can one mimic the essential features of human diseases in an organism like Drosophila, (2) can one cure a model organisms of human disease and (3) will these efforts accelerate the identification of useful therapies for testing in mice and ultimately humans? Here we focus on the use of Drosophila to identify potential treatments for neurodegenerative diseases such as Huntington's and we discuss how well these therapies translate into mammalian systems. BioEssays 26:485–496, 2004. © 2004 Wiley Periodicals, Inc.
Insights into the evolution of the nucleolus by an analysis of its protein domain repertoire
Authors: Staub Eike , Fiziev Petko , Rosenthal André , Hinzmann Bernd 
Published: April 2004

AbstractRecently, the first investigation of nucleoli using mass spectrometry led to the identification of 271 proteins. This represents a rich resource for a comprehensive investigation of nucleolus evolution. We applied a protocol for the identification of known and novel conserved protein domains of the nucleolus, resulting in the identification of 115 known and 91 novel domain profiles. The phyletic distribution of nucleolar protein domains in a collection of complete proteomes of selected organisms from all domains of life confirms the archaebacterial origin of the core machinery for ribosome maturation and assembly, but also reveals substantial eubacterial and eukaryotic contributions to nucleolus evolution. We predict that, in different phases of nucleolus evolution, protein domains with different biochemical functions were recruited to the nucleolus. We suggest a model for the late and continous evolution of the nucleolus in early eukaryotes and argue against an endosymbiotic origin of the nucleolus and the nucleus. Supplementary material for this article can be found on the BioEssays website at http://www.interscience.wiley.com/jpages/0265‐9247/suppmat/index.html. BioEssays 26:567–581, 2004. © 2004 Wiley Periodicals, Inc.
The cadherin–catenin complex as a focal point of cell adhesion and signalling: new insights from three‐dimensional structures
Authors: Gooding Jane M. , Yap Kyoko L. , Ikura Mitsuhiko 
Published: April 2004

AbstractCadherins are a large family of single‐pass transmembrane proteins principally involved in Ca2+‐dependent homotypic cell adhesion. The cadherin molecules comprise three domains, the intracellular domain, the transmembrane domain and the extracellular domain, and form large complexes with a vast array of binding partners (including cadherin molecules of the same type in homophilic interactions and cellular protein catenins), orchestrating biologically essential extracellular and intracellular signalling processes. While current, contrasting models for classic cadherin homophilic interaction involve varying numbers of specific repeats found in the extracellular domain, the structure of the domain itself clearly remains the main determinant of cell stability and binding specificity. Through intracellular interactions, cadherin enhances its adhesive properties binding the cytoskeleton via cytoplasmic associated factors α‐ catenin, β‐catenin and p120ctn. Recent structural studies on classic cadherins and these catenin molecules have provided new insight into the essential mechanisms underlying cadherin‐mediated cell interaction and catenin‐mediated cellular signalling. Remarkable structural diversity has been observed in β‐catenin recognition of other cellular factors including APC, Tcf and ICAT, proteins that contribute to or compete with cadherin/catenin functioning. BioEssays 26:497–511, 2004. © 2004 Wiley Periodicals, Inc.
Battle of the Xs
Authors: Oliver Brian , Parisi Michael 
Published: April 2004

AbstractFemales and males often exhibit conspicuous morphological, physiological and behavioral differences. Similarly, gene expression profiles indicate that a large portion of the genome is sex‐differentially deployed, particularly in the germ line. Because males and females are so fundamentally different, each sex is likely to have a different optimal gene expression profile that is never fully achieved in either sex because of antagonistic selection in females versus males. Males are hemizygous for the X chromosome, which means that recessive male‐favorable de novo mutations on the X chromosome are subject to immediate selection. In females, a recessive female‐favorable mutation on one of two X chromosomes is not available for selection until it becomes frequent enough in the local population to result in homozygous individuals. Given that most mutations are recessive, one would expect that genes or alleles favoring males should accumulate on the X chromosome. Recent microarray work in Drosophila and C. elegans clearly shows the opposite. Why is the X chromosome a highly disfavored location for genes with male‐biased expression in these animals? BioEssays 26:543–548, 2004. Published 2004 Wiley Periodicals, Inc.
Prions at the crossroads: the need to identify the active TSE agent
Authors: Nandi P.K. 
Published: April 2004

AbstractStructural change in the cellular prion protein, PrPC to a ProteinaseK‐resistant β‐sheet‐rich insoluble form PrPSC and its accumulation have been considered to be central to the pathogenesis of the prion diseases (TSE). In a recent paper, Deleault et al have shown that specific endogenous RNA molecules can induce in vitro structural conversion of endogenous PrPC to PrPSC.1 Small highly structured synthetic RNAs can also induce this conversion process.2 However, recent in vivo results show that PrPSC is not directly involved in the prion pathogenesis.3 It is possible, however, that nucleic‐acid‐induced PrPSC associated with the inducer nucleic acid could be the components of the infectious agent. BioEssays 26:469–473, 2004. © 2004 Wiley Periodicals, Inc.
Total Synthesis of 34‐Hydroxyasimicin and Its Photoactive Derivative for Affinity Labeling of the Mitochondrial Complex I
Authors: Han Hongna , Sinha Mantosh K. , D'Souza Lawrence J. , Keinan Ehud , Sinha Subhash C. 
Published: April 2004

AbstractThe asymmetric total synthesis of the 34‐hydroxyasimicin and its 3‐(4‐benzoylphenyl)propionate ester was achieved by means of a convergent synthetic strategy. This ester, which contains eight asymmetric centers, represents the first photoaffinity‐labeling agent that is derived from an Annonaceous acetogenin. The key transformations in the synthesis include the Sharpless asymmetric dihydroxylation reaction, the Wittig olefination reaction, an oxidative cyclization reaction with rhenium(vii) oxide, the Williamson etherification reaction, and a palladium‐catalyzed cross‐coupling reaction. Use of the target molecule for photoaffinity‐labeling studies of bovine mitochondrial NADH‐ubiquinone oxidoreductase (Complex I) may shed light on the structure/function of this intricate enzyme and on the origin of the high antitumor activity exhibited by the Annonaceous acetogenins.
Rational Design of the First Closed Coordination Capsule with Octahedral Outer Shape
Authors: Müller Iris M. , Spillmann Susanne , Franck Holger , Pietschnig Rudolf 
Published: April 2004

AbstractThe rational synthesis of an octahedral coordination capsule in which the triangular faces are covered by single ligands is described herein. Starting with tris(2‐hydroxybenzylidene)triaminoguanidinium chloride [H6L]Cl, we observed an oxidative cyclization of this ligand in the presence of PPh4+ ions resulting in the complex [Pd(H2L′)(PPh3)] (1). The use of 5,5‐diethylbarbiturate (bar2−) as a bridging ligand in the presence of [Co(en)3]3+ (en=ethylenediamine) leads to the formation of a rectangular box with the formula (Et4N)6[{Co{(PdCl)(Pd)L}2(μ‐bar)}2] (2). The analysis of the architecture of compounds 1 and 2 enables the development of a self‐assembly strategy for the synthesis of an octahedral coordination cage 3 with the formula Na4(Et3NH)12[(Pd3L)8{μ‐(bar)}12]⋅x H2O. Compound 3 was characterized by 13C‐MAS‐NMR spectroscopy and single‐crystal structure analysis.
Sterically and Guest‐Controlled Self‐Assembly of Calix[4]arene Derivatives
Authors: Shivanyuk Alexander , Saadioui Mohamed , Broda Frank , Thondorf Iris , Vysotsky Myroslav O. , Rissanen Kari , Kolehmainen Erkki , Böhmer Volker 
Published: April 2004

AbstractIn solvents such as chloroform or benzene, tetraurea calix[4]arenes 1 form dimeric capsules in which one solvent molecule is usually included as guest. To explore the structural requirements for the formation of such hydrogen‐bonded dimers we replaced one p‐tolylurea residue by a simple acetamide function. The resulting calix[4]arene 2 a, substituted at its wide rim with one acetamide and three p‐tolylurea functions, assumes a C1‐symmetrical conformation in apolar solvents as shown by 1H NMR, which is not compatible with the usual capsule. In the crystalline state, four molecules of 2 a, adopting a pinched cone conformation, assemble into a quasi S4‐symmetrical tetramer stabilized by a cyclic array of 24 NH⋅⋅⋅OC hydrogen bonds and four NH⋅⋅⋅π interactions. Four acetamide groups are hydrogen‐bonded to each other and pack tightly in the center of the assembly. All polar residues are buried inside the tetramer, the surface of which is lipophilic. Extensive NMR studies revealed similar structures in apolar solvents such as [D]chloroform or [D6]benzene for calixacetamides 2 a–c. The formation of these tetramers in solution is critically dependent on the size of the amide fragment, so that propionamide 2 d, butyramide 2 e, and p‐tolylamide 2 f form only ill‐defined aggregates. This is caused by steric crowding inside the tetrameric assembly. The tetramers persist during molecular dynamics simulations, and the optimized average structure of the MD run is similar to that found in the crystalline state. Theoretical studies revealed that cooperation of hydrogen bonds with multiple NH⋅⋅⋅π, CH⋅⋅⋅π, and π⋅⋅⋅π attractions make the tetramer more stable than the capsular dimer with the solvent as guest. In the presence of tetraethylammonium salts, however, compounds 2 a–e form dimeric capsular assemblies, each incorporating a single ammonium cation. Only one of two possible regioisomeric dimers is formed, in which both acetamide groups are surrounded by two urea residues. These examples give striking evidence of how self‐assembly in solution can be strongly dependent on subtle structural factors and of how the formation of dimeric capsules can be induced by the presence of an appropriate guest.
Cuprophilic Interactions in Luminescent Copper(I) Clusters with Bridging Bis(dicyclohexylphosphino)methane and Iodide Ligands: Spectroscopic and Structural Investigations
Authors: Fu Wen‐Fu , Gan Xin , Che Chi‐Ming , Cao Qian‐Yong , Zhou Zhong‐Yong , Zhu N. Nian‐Yong 
Published: April 2004

AbstractPolynuclear copper(I) complexes with bridging bis(dicyclohexylphosphino)methane (dcpm) and iodide ligands, [Cu2(dcpm)2(CH3CN)2](BF4)2 (1), [Cu2(dcpm)2](BF4)2 (2), [(CuI)3(dcpm)2] (3), [(CuI)4(dcpm)2] (4), and [(CuI)2(dcpm)2] (5) were prepared and their structures determined by X‐ray crystal analysis. The shortest CuCu distance found in these complexes is 2.475(1) Å for 3. Powdered samples of 1, 3, 4, and 5 display intense and long‐lived phosphorescence with λmax at 460, 626, 590, and 456 nm and emission quantum yields of 0.26, 0.11, 0.12, and 0.56 at room temperature, respectively. In the solid state, 2 displays both a weak emission at 377 and an intense one at 474 nm with an overall emission yield 0.42. The difference in emission properties among complexes 1–5 suggests that both CuCu interaction and coordination around the copper(I) center affect the excited state properties. A degassed solution of 2 in acetone gives a bright red emission with λmax at 625 nm at room temperature. The difference absorption spectra of the triplet excited states of 1–5 in acetonitrile show broad absorption peaks at 340–410 and 850–870 nm.