bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallographic report: Aquadicylcohexyltin(IV) bis(2‐picolinate) ethanol solvate
Authors: Dakternieks Dainis , Duthie Andrew , Smyth Douglas R. , Stapleton Clynton P. D. , Tiekink Edward R. T. 
Published: December 2003

AbstractThe tin atom in the title compound is in a distorted pentagonal bipyramidal geometry defined by two sets of nitrogen and oxygen donors derived from the carboxylate ligands, two carbon atoms from the cyclohexyl substituents and an oxygen atom from the coordinated water molecule; CSnC 170.85(15)°. Extensive hydrogen bonding occurs in the lattice. Copyright © 2004 John Wiley & Sons, Ltd.
The effect of cholesterol on the adsorption of phenyltin compounds onto phosphatidylcholine and sphingomyelin liposome membranes
Authors: Gabrielska Janina , Przestalski Stanisław , Miszta Adam , Soczyńska‐Kordala Monika , Langner Marek 
Published: December 2003

AbstractOrganometallic compounds are widely spread in the human environment sometimes, causing a substantial health risk. Their amphiphilic character enables them to intercalate and penetrate cell membranes, potentially affecting various vital cell functions. Compound adsorption onto the membrane depends on the compound properties, as well as on the membrane composition and state. When adsorbing onto the lipidic surface, phenyltins localize at areas where lipid bilayer organization is compatible with compound spatial requirements. The lipid bilayer is a dynamic and laterally nonuniform structure with complex local and global architecture correlated with a variety of cell functions. The selective binding of a toxic compound to selected membrane areas may, therefore, interfere with some types of cellular process. We present experimental results concerning phenyltin adsorption onto the lipid bilayer surface measured with the fluorescent probe fluorescein‐PE. Model lipid bilayers were formed from lipid mixtures mimicking various plasma membrane regions. The adsorption of Ph3SnCl and P2SnCl2 onto the phosphatidylcholine–cholesterol bilayer was qualitatively different from sphingomyelin–cholesterol. The results presented indicate that phenyltins are likely to accumulate in areas containing phosphatidylcholine, outside of lipid rafts. Copyright © 2004 John Wiley & Sons, Ltd.
Crystallographic report: Dimeric tetraphenyl‐1‐hydroxo‐3‐trifluoromethanesulfonatodistannoxane, [Ph2(HO)SnOSn(O3SCF3)Ph2]2
Authors: Beckmann Jens , Dakternieks Dainis , Duthie Andrew , Mitchell Cassandra 
Published: December 2003

AbstractThe molecular structure of the title compound, obtained by an adventitious phenyl group cleavage of Ph3SnOSnPh3 with triflic acid, reveals discrete centrosymmetric units of [Ph2(HO)SnOSn(O3SCF3)Ph2]2 that are loosely associated via hydrogen bonding. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of synthetic and commercial trisiloxane surfactant materials
Authors: Bonnington L. S. , Henderson W. , Zabkiewicz J. A. 
Published: December 2003

AbstractThe organosilicone surfactant Silwet L‐77® (L‐77), used as an agrochemical adjuvant, is a mixture comprised predominantly of [(CH3)3SiO]2(CH3)Si(CH2)3(OCH2CH2)nOCH3 oligomers (n = 3–16, average n ≈ 7.5). The commercially available L‐77 mixture was purified by reversed‐phase high‐performance liquid chromatography (HPLC) to obtain individual trisiloxane surfactant components. Pure oligomers (n = 3, 6 and 9) were also synthesized. Synthesis was achieved by hydrosilylation of monomeric ethoxylate monomethyl ether starting reagents. Pure hexa‐ and nona‐ethylene glycols were produced by condensation of smaller oligomers.Atmospheric‐pressure ionization mass spectrometry (MS) methods were used to characterize fully the commercial L‐77 product and synthesized or isolated components. The application of Fourier‐transform ion cyclotron resonance MS and online HPLC–electrospray ionization MS techniques to the analysis of this surfactant are described here. The application of these analytical techniques also enabled elucidation of the synthetic by‐products present in the commercial formulation.In addition, physico‐chemical properties specific to agrochemical uses, such as droplet spread areas on plant foliage and surface tension for the different oligomer solutions, are also reported. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of calix[4]arenes modified with germanium‐containing side chains on the upper rim
Authors: Sakurai Takayuki , Takeuchi Yoshito 
Published: December 2003

AbstractWith the expectation to prepare a new type of heteroditopic host, a series of calix[4]arenes modified with germanium‐containing side chains at the upper rim was prepared. Compounds 1 and 2 bear two or four triethylgermyl moieties respectively, and compounds 3 and 4 bear two or four trimethylgermyl moieties respectively. For 1 and 2, the hydroxy groups at the lower rim are either tosylated (series a) or kept free (series b). For reference, a carbon analog of 3, compound 5, was also prepared. Unfortunately, all calixarenes prepared failed to show any appreciable cation transport property, indicating that the structure designed, i.e. a calixarene with germanium‐containing side chains at the upper rim, cannot meet the requirement for an appropriate heteroditopic host. Copyright © 2004 John Wiley & Sons, Ltd.
111In–L–LDL and 153Gd–L–LDL as radiotracers for detection of AR4‐2J rat pancreatic tumors
Authors: Ratovo Ginette , Souchard Jean‐Pierre , Urizzi Pascale , Coulais Yvon , Nepveu Françoise , Hollande Etienne 
Published: December 2003

AbstractPancreatic cancer has an extremely poor prognosis, due, in part, to lack of methods for early diagnosis. The present study was designed to evaluate the potential of labeling low‐density lipoprotein (LDL) with a radionuclide using a lipid chelating agent, bis(stearylamide) of diethylenetriaminepentaacetic acid (L), to detect pancreatic tumors by gamma‐scintigraphy. Previous studies indicated that the difficulty of visualization of pancreatic tumors was due to their poor vascularization. This study compares the ability of two radiotracers, 111In–L–LDL and 153Gd–L–LDL to target highly vascularized rat pancreatic tumors (AR4‐2J) implanted in nude mice. Biodistribution studies showed that the tumor uptake of 111In–L–LDL and 153Gd–L–LDL tracers was twofold and fivefold higher respectively than with the controls (111In citrate and 153Gd citrate respectively). These tracers would thus be suitable for scintigraphic imaging.We show here that LDL could be employed as a delivery system for tracers such as 111In or 153Gd when these two radionuclides are complexed by a lipid‐chelating anchor, and that 111In–L–LDL and 153Gd–L–LDL enabled better visualization of the pancreatic tumor tissues, with a better result with 153Gd–L–LDL. Copyright © 2004 John Wiley & Sons, Ltd.
Electrochemically reduced tungsten‐based active species as catalysts for cross‐metathesis reactions: cross‐metathesis of erucic acid with 2‐octene
Authors: Çetinkaya Sevil , Düz Bülent , İmamoǧlu Yavuz 
Published: December 2003

AbstractThe cross‐metathesis of erucic acid, (CH3(CH2)7CHCH(CH2)11COOH), with an excess of 2‐octene in the presence of an electrochemically produced tungsten‐based catalyst has been studied. Cross‐ and self‐hydrocarbon products, viz. 2‐undecene (C11), 6‐dodecene (C12) and 6‐pentadecene (C15), were detected. The influence of several parameters, such as the 2‐octene/erucic acid and 2‐octene/catalyst ratios and the reaction time, on the yield of the cross‐metathesis product, 6‐pentadecene, was studied. The cross‐metathesis of functionalized olefins in the presence of an Al–e−–WCl6–CH2Cl2 system has not been reported in the literature so far. The cross‐metathesis products in the presence of this catalyst system can be obtained with high yield and high specificity. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and catalytic properties of 1‐alkyl‐2‐imidazolineruthenium(II) complexes
Authors: Özdemir İsmail , Çetinkaya Bekir , Demir Serpil , Çetinkaya Engin , Gürbüz Nevin , Çiçek Metin 
Published: December 2003

AbstractNew [RuCl2(imidazoline)(arene)] complexes have been prepared. The complexes were characterized by conventional spectroscopic methods and elemental analyses. Upon reaction with 1,1‐diphenylprop‐2‐ynol they generate catalyst precursors that can perform the cycloisomerization of diallyltosylamide into N‐tosyl‐α‐methylenepyrrolidine. Copyright © 2004 John Wiley & Sons, Ltd.
Exposure assessment of ELF magnetic fields in urban environments in Extremadura (Spain)
Authors: Paniagua Jesús M. , Jiménez Antonio , Rufo Montaña , Antolín Alicia 
Published: December 2003

AbstractWe present the results of a study of the extremely low frequency (ELF) magnetic fields in urban environments of the Extremadura region (Spain). The study included a spectral analysis, an analysis of the temporal variation, and spot measurements in the streets of four cities. The spectral analysis showed that the main source of magnetic field exposure was that corresponding to the principal power frequency (50 Hz) and its third harmonic. The magnetic flux density measured at one point over 24 h presented rapid fluctuations in short time periods. Smoothing the time series eliminated these fluctuations, showing a temporal evolution associated with the differing levels of power consumption over the course of the day. The values of the spot measurements taken in the streets were all below the ICNIRP reference level, although 30% surpassed 0.2 µT, the value that some epidemiological studies take as the threshold above which there exist risks of effects that could be harmful to health. The values found for the magnetic flux density in these urban settings were generally greater than values reported in the literature for residential areas, and similar to, although in some cases less than those in workplace environments. Bioelectromagnetics 25:58–62, 2004. © 2003 Wiley‐Liss, Inc.
Radial arm maze performance of rats following repeated low level microwave radiation exposure
Authors: Cobb Brenda L. , Jauchem James R. , Adair Eleanor R. 
Published: December 2003

AbstractWe examined the possibility of changes in “working” memory of rats following whole body exposure to microwave (MW) radiation. During each of 10 days, we exposed rats within circularly polarized waveguides for 45 min to 2450 MHz fields at whole body SARs of 0.6 W/kg (2 μs pulses, 500 pps), followed by testing in a 12 arm, radial arm maze (RAM). Rats received a preexposure injection of one of three psychoactive compounds or saline, to determine whether a compound would interact with MW exposure to affect performance in the maze. Error rate, i.e., reentry into arms already visited, and time to criterion data for 10 consecutive days of testing were analyzed by a three way analysis of variance (ANOVA) using main effects of “exposure” and “drug” and a repeated factor of “test day.” Our alpha limit for significance was P < .05. Analyzes of error rates revealed no significant exposure effect, no significant drug effect and no significant interaction between the two main factors. There was a significant difference in test days, as expected, with repeated test‐trial days, which indicates that learning was accomplished. There was no significant interaction of test day and the other two factors. The results of our analyzes of time to criterion data included no significant exposure effect, a significant drug effect, a significant test day effect, and a significant interaction between drug and test day factors. Post hoc analyzes of the drug factor revealed that rats treated with either physostigmine or nalrexone hydrochloride, took significantly longer to complete the maze task than rats pretreated with saline or with naloxone methodide. We conclude that there is no evidence from the current study that exposure to of MW radiation under parameters examined caused decrements in the ability of rats to learn the spatial memory task. Bioelectromagnetics 25:49–57, 2004. Published 2003 Wiley‐Liss, Inc.
A single magnetic field exposure system for sequential investigation of real time and downstream cellular responses
Authors: Rao Raj R. , Kisaalita William S. 
Published: December 2003

AbstractTo be able to correlate real time membrane potential or ion flux changes with further downstream gene transcription responses due to extremely low frequency (ELF) electromagnetic field (EMF) exposure, we devised an experimental system consisting of a pair of symmetric circular coils. This system can be used on an inverted microscope stage (real time signaling) as well as inside controlled environment incubators (gene transcription end points). The system includes a unique, custom made switch box for blinding the experimental staff and a power amplifier. We report herein the design and characterization of the system with respect to parameters considered important in in vitro ELF–EMF exposure studies, including linear magnetic field distribution, compensation for microscope objective lens interference, heating effects of the coils, and harmonic content of the signals. Bioelectromagnetics 25:27–32, 2004. © 2003 Wiley‐Liss, Inc.
Electromagnetic field exposure and health among RF plastic sealer operators
Authors: Wilén Jonna , Hörnsten Rolf , Sandström Monica , Bjerle Per , Wiklund Urban , Stensson Olov , Lyskov Eugene , Mild Kjell Hansson 
Published: December 2003

AbstractOperators of RF plastic sealers (RF operators) are an occupational category highly exposed to radiofrequency electromagnetic fields. The aim of the present study was to make an appropriate exposure assessment of RF welding and examine the health status of the operators. In total, 35 RF operators and 37 controls were included. The leakage fields (electric and magnetic field strength) were measured, as well as induced and contact current. Information about welding time and productivity was used to calculate time integrated exposure. A neurophysiological examination and 24 h ECG were also carried out. The participants also had to answer a questionnaire about subjective symptoms. The measurements showed that RF operators were exposed to rather intense electric and magnetic fields. The mean values of the calculated 6 min, spatially averaged E and H field strengths, in line with ICNIRP reference levels, are 107 V/m and 0.24 A/m, respectively. The maximum measured field strengths were 2 kV/m and 1.5 A/m, respectively. The induced current in ankles and wrists varied, depending on the work situation, with a mean value of 101 mA and a maximum measured value of 1 A. In total, 11 out of 46 measured RF plastic sealers exceeded the ICNIRP reference levels. RF operators, especially the ready made clothing workers had a slightly disturbed two‐point discrimination ability compared to a control group. A nonsignificant difference between RF operators and controls was found in the prevalence of subjective symptoms, but the time integrated exposure parameters seem to be of importance to the prevalence of some subjective symptoms: fatigue, headaches, and warmth sensations in the hands. Further, RF operators had a significantly lower heart rate (24 h registration) and more episodes of bradycardia compared to controls. Bioelectromagnetics 25:5–15, 2004. © 2003 Wiley‐Liss, Inc.
Lack of alterations on meiotic chromosomes and morphological characteristics of male germ cells in mice exposed to a 60 Hz and 2.0 mT magnetic field
Authors: Heredia‐Rojas J. Antonio , Caballero‐Hernandez Diana E. , Rodriguez‐de la Fuente Abraham O. , Ramos‐Alfano Gerardo , Rodriguez‐Flores Laura E. 
Published: December 2003

AbstractThe effect of in vivo exposure of mice to a 60 Hz sinusoidal magnetic field (MF) at 2.0 mT on male germ cells was studied. The cytological endpoints measured included meiotic chromosome aberrations in spermatocytes and sperm morphology. Three independent experiments were carried out: (a) animals exposed for 72 h, (b) 10 days/8 h daily, and (c) 72 h exposure to MF plus 5 mg/kg of Mitomycin‐C. No statistically significant differences indicative of MF effects were observed between MF exposed and control animals. In addition, an opposite effect between MF exposure and Mitomycin‐C treatment in terms of chromosomal aberrations and sperm morphology was observed. Bioelectromagnetics 25:63–68, 2004. © 2003 Wiley‐Liss, Inc.
Photosynthetic eukaryotes unite: endosymbiosis connects the dots
Authors: Bhattacharya Debashish , Yoon Hwan Su , Hackett Jeremiah D. 
Published: December 2003

AbstractThe photosynthetic organelle of algae and plants (the plastid) traces its origin to a primary endosymbiotic event in which a previously non‐photosynthetic protist engulfed and enslaved a cyanobacterium. This eukaryote then gave rise to the red, green and glaucophyte algae. However, many algal lineages, such as the chlorophyll c‐containing chromists, have a more complicated evolutionary history involving a secondary endosymbiotic event, in which a protist engulfed an existing eukaryotic alga (in this case, a red alga). Chromists such as diatoms and kelps then rose to great importance in aquatic habitats. Another algal group, the dinoflagellates, has undergone tertiary (engulfment of a secondary plastid) and even quaternary endosymbioses. In this review, we examine algal diversity and show endosymbiosis to be a major force in algal evolution. This area of research has advanced rapidly and long‐standing issues such as the chromalveolate hypothesis and the extent of endosymbiotic gene transfer have recently been clarified. BioEssays 26:50–60, 2004. © 2003 Wiley Periodicals, Inc.
Functional genomics of the nicotinic acetylcholine receptor gene family of the nematode, Caenorhabditis elegans
Authors: Jones Andrew K. , Sattelle David B. 
Published: December 2003

AbstractNicotinic acetylcholine receptors (nAChRs) are ligand‐gated ion channels that bring about a diversity of fast synaptic actions. Analysis of the Caenorhabditis elegans genome has revealed one of the most‐extensive and diverse nAChR gene families known, consisting of at least 27 subunits. Striking variation with possible functional implications has been observed in normally conserved motifs at the acetylcholine‐binding site and in the channel‐lining region. Some nAChR subunits are particular to neurons whilst others are present in both neurons and muscles. The localization of subunits in non‐synaptic regions suggests novel roles for nAChRs. Genetic and heterologous expression studies have identified a subset of nAChR subunits that are important drug targets while the study of mutants has identified genes functionally‐linked to nAChRs. Future studies using C. elegans offer the prospect of increasing our understanding of the functional diversity of a complex nAChR gene family as well as addressing the role of nAChRs and associated proteins in human disorders. BioEssays 26:39–49, 2004.© 2003 Wiley Periodicals, Inc.
Neuroprotection by monoamine oxidase B inhibitors: a therapeutic strategy for Parkinson's disease?
Authors: Tabakman Rinat , Lecht Shimon , Lazarovici Philip 
Published: December 2003

AbstractParkinsonism (PD) is a neurodegenerative disorder of the brain resulting in dopamine deficiency caused by the progressive death of dopaminergic neurons. PD is characterized by a combination of rigidity, poverty of movement, tremor and postural instability. Selegiline is a selective and irreversible propargylamine type B monoamine oxidase (MAO‐B) inhibitor. This drug, which inhibits dopamine metabolism, has been effectively used in the treatment of PD. However, its therapeutic effects are compromised by its many neurotoxic metabolites. To circumvent this obstacle, a novel MAO‐B inhibitor, rasagiline, was developed. Paradoxically, the neuroprotective mechanism of propargylamines in different neuronal models appears to be independent of MAO‐B inhibition. Recent investigations into the neuroprotective mechanism of propargylamines indicate that glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), MAO‐B and/or other unknown proteins may represent pivotal proteins in the survival of the injured neurons. Delineation of the mechanism(s) involved in the neuroprotective effects exerted by MAO‐B inhibitors may provide the key to preventive novel therapeutic modalities. BioEssays 26:80–90, 2004. © 2003 Wiley Periodicals, Inc.
Mating‐type locus homozygosis, phenotypic switching and mating: a unique sequence of dependencies in Candida albicans
Authors: Soll David R. 
Published: December 2003

AbstractA small proportion of clinical strains of Candida albicans undergo white–opaque switching. Until recently it was not clear why, since most strains carry the genes differentially expressed in the unique opaque phase. The answer to this enigma lies in the mating process. The majority of C. albicans strains are heterozygous for the mating type locus MTL (a/α) and cannot undergo white–opaque switching. However, when these cells undergo homozygosis at the mating type locus (i.e., become a/a or α/α), they can switch, and they must switch in order to mate. Even though the newly identified stages of mating mimic those of Saccharomyces cerevisiae, the process differs in its dependency on switching, and the effects switching has on gene regulation. This unique feature of C. albicans mating appears to be intimately intertwined with its pathogenesis. The unique, newly discovered dependencies of switching on homozygosis at the MTL locus and of mating on switching are, therefore, reviewed within the context of pathogenesis. BioEssays 26:10–20, 2004. © 2003 Wiley Periodicals, Inc.
The next step in systems biology: simulating the temporospatial dynamics of molecular network
Authors: Zhu Hao , Huang Sui , Dhar Pawan 
Published: December 2003

AbstractAs a result of the time‐ and context‐dependency of gene expression, gene regulatory and signaling pathways undergo dynamic changes during development. Creating a model of the dynamics of molecular interaction networks offers enormous potential for understanding how a genome orchestrates the developmental processes of an organism. The dynamic nature of pathway topology calls for new modeling strategies that can capture transient molecular links at the runtime. The aim of this paper is to present a brief and informative, but not all‐inclusive, viewpoint on the computational aspects of modeling and simulation of a non‐static molecular network. BioEssays 26:68–72, 2004. © 2003 Wiley Periodicals, Inc.
LAT: a T lymphocyte adapter protein that couples the antigen receptor to downstream signaling pathways
Authors: Sommers Connie L. , Samelson Lawrence E. , Love Paul E. 
Published: December 2003

AbstractAdapter molecules in a variety of signal transduction systems link receptors to a limited number of commonly used downstream signaling pathways. During T‐cell development and mature T‐cell effector function, a multichain receptor (the pre‐T‐cell antigen receptor or the T‐cell antigen receptor) activates several protein tyrosine kinases. Receptor and kinase activation is linked to distal signaling pathways (PLC‐γ1 activation, Ca2+ influx, PKC activation and Ras/Erk activation) via the adapter protein LAT (Linker for Activation of T cells). Structure/function studies of LAT including expression of selected LAT point mutations in vivo reveals that these multiple pathways are integrated at the level of the LAT adapter. These studies suggest that similar levels of control may be found in other systems where adapter molecules are known to have important functions. BioEssays 26:61–67, 2004. Published 2003 Wiley Periodicals, Inc.