bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiohalogen incorporation into organic systems
Authors: Bolton R. 
Published: January 2005

AbstractThis Review reports the more recent applications of radiohalogen labelling in organic compounds. Modern synthetic methods place more emphasis upon substitution at specific sites. Electrophilic substitution, especially at aromatic carbon atoms, involves displacement of halogen or of metals rather than the earlier popular halogen‐deprotiation processes. Nucleophilic displacement, at either aliphatic or aromatic sites, has also become widespread since it may be made more selective by the inclusion of appropriate activating groups or suitable displaced groups. Microwave and thermally induced methods are both reported with a critical assessment of the value of each process. Copyright © 2002 John Wiley & Sons, Ltd.
Rapid microwave‐assisted cleavage of methyl phenyl ethers: new method for synthesizing desmethyl precursors and for removing protecting groups
Authors: Fredriksson Anna , Stone‐Elander Sharon 
Published: January 2005

AbstractA new microwave‐enhanced method for rapid demethylation of methyl phenyl ethers using neat methanesulfonic acid (CH3SO3H) is presented. Using a monomodal microwave cavity, cleavage of anisole (1), used as model compound, to phenol (2) was achieved with high conversions (ca 80%) in very short reaction times (10–20 s). The feasibility of cleaving one or both of two methoxy groups was illustrated with 4‐(3‐bromoanilino)‐6,7‐dimethoxy‐quinazoline (PD153035, 3). High conversions (⩾82%) of 3 were attained with four different conditions (i.e. combination of input effect (35–125 W) and time (15 s–2 min)). 4‐(3‐Bromoanilino)‐7‐hydroxy‐6‐methoxyquinazoline (4), 4‐(3‐bromoanilino)‐6‐hydroxy‐7‐methoxyquinazoline (5) and 4‐(3‐bromoanilino)‐6,7‐dihydroxyquinazoline (6), the possible mono‐ or di‐demethylated compounds, were obtained. Methods for rapid demethylations are of interest in radiochemistry for post‐labeling deprotections of hydroxyl containing aromatic rings and also provide a more direct route for synthesizing precursor compounds for labeling by alkylation. Copyright © 2002 John Wiley & Sons, Ltd.
Src homology‐2 domain binding assays by scintillation proximity and surface plasmon resonance
Authors: Mandine Eliane , Gofflo Dominique , Jean‐Baptiste Véronique , Sarubbi Edoardo , Touyer Gaetan , Deprez Pierre , Lesuisse Dominique 
Published: January 2005

AbstractVarious SH2 competitive binding assays, based on different techniques, have been described in the literature to identify and characterize SH2 ligands. The consideration that most reported methods show experimental limitations associated with assay parameters has prompted us to base our Src‐SH2 inhibitor discovery program on the use of two different assays.
In this study, two conceptually different biochemical methods designed to discover Src‐SH2 inhibitors, respectively scintillation proximity assay (SPA) and surface plasmon resonance (SPR), have been evaluated and compared. For its high sensitivity and adaptability to automation SPA was chosen for high capacity screening (primary screen), whereas SPR was used for hits confirmation (secondary screening). However with the drastic improvement of inhibitor affinities, the limit of sensitivity was rapidly reached for the SPR assay based on the canonical pYEEI ligand. The substitution of the natural, monophosphorylated peptide ligand with a triphosphorylated peptide has allowed us to remarkably increase its sensitivity, so that molecules with nanomolar affinities could be easily differentiated in terms of IC50 ranking. Such a new, improved SPR assay can be of great interest for the study of high affinity ligands of different SH2‐based drug targets. Copyright © 2001 John Wiley & Sons, Ltd.
NF‐κB pathway protects cochlear hair cells from aminoglycoside‐induced ototoxicity
Authors: Jiang Hongyan , Sha Su‐Hua , Schacht Jochen 
Published: January 2005

AbstractCell death in outer hair cells of the mammalian inner ear induced by aminoglycoside antibiotics is mediated by reactive oxygen species (ROS) and can be prevented by antioxidants. The current study investigates the role of the nuclear factor (NF)‐κB pathway in cell death or survival in adult CBA mice. Kanamycin (700 mg/kg subcutaneously, twice per day) progressively destroys hair cells but after 7 days of treatment auditory function and morphology are not yet affected significantly, permitting investigations of early events in drug‐induced cell death. Immunostaining for 4‐hydroxynonenal, indicative of lipid peroxidation, was elevated in the cochlea, but there was no effect on nitrotyrosine, a marker for peroxynitrite. NF‐κB was increased at 3 hr, 3 days, and 7 days of treatment, with p50 and p65 proteins as its most abundant subunits. Immunoreactivity for p50 was present in nuclei of inner hair cells and supporting cells that survive the drug treatment. In contrast, nuclei of outer hair cells were devoid of label. Concomitant injections of antioxidants, however, such as 2,3‐dihydroxybenzoic acid or salicylate (which prevent cell death induced by kanamycin), promoted the translocation of NF‐κB into the nuclei of outer hair cells. In addition, kanamycin treatment decreased tyrosine phosphorylation of the inhibitory IκBα protein, leading to increased IκBα levels in the cochlea; the effect was reversed by cotreatment with antioxidants. These results suggest that changes in the redox state of the cochlea stimulate the activation of NF‐κB and that this activation is cell protective. © 2005 Wiley‐Liss, Inc.
Schwann cells exhibit excitotoxicity consistent with release of NMDA receptor agonists
Authors: Wu Sheng‐Zhou , Jiang Shujun , Sims Terry J. , Barger Steven W. 
Published: January 2005

AbstractNeurodegenerative effects of Schwann cells transplanted into the central nervous system have been observed previously. We report here that conditioned medium from Schwann cell cultures exhibit degenerative influences on hippocampal neurons. Aliquots of Schwann cell‐conditioned medium compromised the morphologic integrity of the neurons, markedly elevated their intracellular calcium concentrations, and decreased their viability. The degenerative effects of Schwann cell medium on neuronal morphology and viability were blocked by N‐methyl‐D‐aspartate (NMDA) receptor antagonists D‐(−)‐2‐amino‐5‐phosphonopentanoic acid (D‐APV) and 5,7‐dicholorokynurenic acid (DCKA). Glutamate was detected in Schwann cell‐conditioned medium at a concentration on the order of 10−5 M. D‐Amino acid oxidase (DAAOx) also attenuated the neurotoxicity exhibited by Schwann cells. These data suggest that Schwann cells release biologically relevant concentrations of excitotoxins that include glutamate and D‐serine. © 2005 Wiley‐Liss, Inc.
Identification and characterization of Caenorhabditis elegans palmitoyl protein thioesterase1
Authors: Porter Morwenna Y. , Turmaine Mark , Mole Sara E. 
Published: January 2005

AbstractInfantile neuronal ceroid lipofuscinosis (INCL; Batten disease) is a severe neurodegenerative disorder of childhood characterized by the accumulation of autofluorescent storage material in lysosomes. It is caused by mutation of the CLN1/PPT1 gene, which encodes the lysosomal enzyme palmitoyl protein thioesterase‐1 (PPT1), but the mechanism of disease pathogenesis and substrates for the enzyme are unknown. Caenorhabditis elegans is a simple nematode worm, with a fully sequenced genome, which is easy to maintain and manipulate. It has a completely mapped cell lineage and nervous system and has already provided clues about the pathogenesis of several human neuronal and lysosomal storage disorders. We have identified and characterized a PPT1 homologue in C. elegans. We found that, although this gene was not essential for the animal's survival, its mutation resulted in a mild developmental and reproductive phenotype, affected the number and size of mitochondria, and resulted in an abnormality in mitochondrial morphology, possibly suggestive of a role for this organelle in INCL pathogenesis. This strain, deleted for ppt‐1, potentially provides a model system for the study of PPT1 and the pathogenesis of INCL. © 2005 Wiley‐Liss, Inc.
Loss of brain‐derived neurotrophic factor gene allele exacerbates brain monoamine deficiencies and increases stress abnormalities of serotonin transporter knockout mice
Authors: Ren‐Patterson Renee F. , Cochran Lauren W. , Holmes Andrew , Sherrill Suzanne , Huang Su‐Jan , Tolliver Teresa , Lesch Klaus‐Peter , Lu Bai , Murphy Dennis L. 
Published: January 2005

AbstractTo study the neurochemical and behavioral effects of altered brain‐derived neurotrophic factor (BDNF) expression on a brain serotonin system with diminished serotonin transport capability, a double‐mutant mouse model was developed by interbreeding serotonin transporter (SERT) knockout mice with BDNF heterozygous knockout mice (BDNF +/–), producing SERT –/– × BDNF +/– (sb) mice. Prior evidence implicates serotonin and SERT in anxiety and stress responses. Some studies have shown that BDNF supports serotonergic neuronal development, leading to our hypothesis that reduced BDNF availability during development might exaggerate the consequences of absent SERT function. In the present study, brain serotonin and 5‐hydroxyindol acetic acid concentrations in male sb mice were significantly reduced in the hippocampus and hypothalamus compared with wild‐type control SB mice, BDNF‐deficient Sb mice, and serotonin transporter knockout sB mice. The sb mice had significantly increased anxiety‐like behaviors compared with SB, Sb, and sB mice as measured on the elevated plus maze test. These sb mice also had significantly greater increases in plasma adrenocorticotrophic hormone than mice with other genotypes after a stressful stimulus. Analysis of neuronal morphology showed that hypothalamic and hippocampal neurons exhibited 25–30% reductions in dendrites in sb mice compared with SB control mice. These findings support the hypothesis that genetic changes in BDNF expression interact with serotonin and other circuits that modulate anxiety and stress‐related behaviors. Thus, this double‐mutant mouse model should prove valuable in studying other gene × gene consequences for brain plasticity as well as in evaluating epistatic interactions of BDNF and serotonin transporter gene polymorphisms in neuropsychiatric disorders. © 2005 Wiley‐Liss, Inc.
A renewal cluster model for the inter‐arrival times of rainfall events
Authors: Cowpertwait Paul S.P. 
Published: January 2005

AbstractA statistical model, based on a renewal cluster point process, is proposed and used to infer the distributional properties of dry periods in a continuous‐time record. The model incorporates a mixed probability distribution in which inter‐arrival times are classified into two distinct types, representing cyclonic and anticyclonic weather. This results in rainfall events being clustered in time, and enables objective probabilistic statements to be made about storm properties, e.g. the expected number of events in a storm cluster. The model is fitted to data taken from a gauge near Wellington, New Zealand, by maximizing the likelihood function with respect to the parameters. The Akaike Information Criteria is used to select the best fitting distributions from a range of candidates. The Log‐Normal distribution is found to provide the best fit to the times between successive storm clusters, whilst the Weibull distribution is found to provide the best fit to the times between successive events in the same storm cluster. Harmonic curves are used to provide a parsimonious parameterization, allowing for the seasonal variation in precipitation. Under the fitted model, the interval series is transformed into a residual series, which is assessed to determine overall goodness‐of‐fit. Copyright © 2001 Royal Meteorological Society
Modelling low frequency variability in Southern Hemisphere extra‐tropical cyclone characteristics and its sensitivity to sea‐surface temperature
Authors: Reason C.J.C. , Murray R.J. 
Published: January 2005

AbstractThe outflow regions of the western boundary currents of the Southern Hemisphere and their extensions into the South Indian Ocean, South Pacific and South Atlantic Currents are prominent areas of low frequency variability in sea‐surface temperature (SST). One mechanism of decadal/multidecadal variability involves modulation of surface heat flux exchange and the track and intensity of extra‐tropical cyclones and associated frontal systems in response to a zonal mid‐latitude SST anomaly. Here, the influence of this type of SST pattern on cyclone properties is investigated by applying a vortex tracking scheme to atmospheric general circulation model integrations. In order to assess the subdecadal to multidecadal scale response, these integrations were conducted for a 21‐year period with forcing consisting of a warm SST anomaly stretching across the Southern Hemisphere mid‐latitudes. In response to this forcing, a large‐scale trough at mid‐latitudes and ridging at higher latitudes are generated in the model. Associated with this change in Southern Hemisphere baroclinicity are increases in the density and flux of cyclonic systems in the 40°–55°S zone but decreases poleward of this latitude belt. It is found that the model response weakens throughout the Southern Hemisphere mid‐ to high‐latitudes in the second decade compared to the first but that there is less evidence of a hemispheric weakening in the second quinquennium relative to the first. Implications of these results for mechanisms of decadal/multidecadal climate variability are discussed. Copyright © 2001 Royal Meteorological Society.
Abrupt and sudden climatic transitions and fluctuations: a review
Authors: Lockwood J.G. 
Published: January 2005

AbstractThis review paper summarizes recent research work on abrupt climatic changes and oscillations. The climatic system is viewed as a dissipative, highly non‐linear system, under non‐equilibrium conditions, and, as such, should be expected to have some unusual properties. These unusual properties include bifurcation points with marked instability just before the point, magnification of semi‐periodic oscillations around bifurcation points, and variations in the strength of teleconnections with distance from equilibrium. These properties are discussed and illustrated for the climatic system using both the historical, Holocene and glacial climatic records. It is found that there are abrupt climatic changes and oscillations on all time‐scales. The amplitudes and frequencies of climate variability and teleconnections are found to vary between different time periods. A number of persistent oscillations exist, particularly one about 1500 years, but their amplitudes vary considerably between time periods. The Holocene appears to be no more climatically benign than the similar period in the Eemian. The importance of the North Atlantic thermohaline circulation for generating abrupt climatic changes in Europe, particularly in association with sudden pulses of fresh water, is illustrated. The concept of antiphase temperature changes between the North and South Atlantic is discussed. Externally generated abrupt climatic deteriorations owing to explosive volcanic eruptions and variations in solar irradiance are also discussed. Copyright © 2001 Royal Meteorological Society
Current approaches to seasonal to interannual climate predictions
Authors: Goddard L. , Mason S.J. , Zebiak S.E. , Ropelewski C.F. , Basher R. , Cane M.A. 
Published: January 2005

AbstractThis review paper presents an assessment of the current state of knowledge and capability in seasonal climate prediction at the end of the 20th century. The discussion covers the full range of issues involved in climate forecasting, including (1) the theory and empirical evidence for predictability; (2) predictions of surface boundary conditions, such as sea surface temperatures (SSTs) that drive the predictable part of the climate; (3) predictions of the climate; and (4) a brief consideration of the application of climate forecasts. Within this context, the research of the coming decades that seeks to address shortcomings in each area is described. Copyright © 2001 Royal Meteorological Society
Evolution of a periglacial landscape in the Late Devensian: environments and palaeobotany of the Mepal area, Cambridgeshire, England
Authors: West R. G. , Burton R. G. O. , Andrew R. , Pettit M. E. 
Published: January 2005

AbstractThe landscape evolution of the Mepal area from Late Devensian Block Fen Terrace times to the beginning of the Flandrian, a period of ca. 8000 radiocarbon years, is reconstructed. Stratigraphy is based on borehole transects and single boreholes, centred on a depression between the Block Fen Terrace and the Isle of Ely. Within the depression is a Devensian late‐glacial sequence, with the Windermere Interstadial represented by radiocarbon‐dated organic sediments. Pollen and plant macroscopic remains of the late‐glacial sediments are analysed. Plant communities with Betula developed in the interstadial. Before and after the interstadial there is much reworked pollen in the inorganic sediments, derived from local pre‐Devensian Pleistocene sediments, including temperate Ipswichian Stage sediments, and from mass‐wasting of the local Jurassic bedrock. Periods of such mass‐movement occur before and after the deposition of the late‐glacial lake sediments. Deposition of aeolian sediment occurs later than the main period of mass movement, but before the Windermere Interstadial. The relationship of the aeolian sediments in time and space to permafrost, indicated by local contraction polygons and cracks, is discussed. Solifluction diverted the flow of the River Great Ouse from a northeast direction in Block Fen Terrace times to a southwest direction as a channel developed to the west of the Chatteris–March ‘island’. This led to a drainage divide in Flandrian times. Copyright © 2002 John Wiley & Sons, Ltd.
Stomatal evidence for a decline in atmospheric CO2 concentration during the Younger Dryas stadial: a comparison with Antarctic ice core records
Authors: Mcelwain J. C. , Mayle F. E. , Beerling D. J. 
Published: January 2005

AbstractA recent high‐resolution record of Late‐glacial CO2 change from Dome Concordia in Antarctica reveals a trend of increasing CO2 across the Younger Dryas stadial (GS‐1). These results are in good agreement with previous Antarctic ice‐core records. However, they contrast markedly with a proxy CO2 record based on the stomatal approach to CO2 reconstruction, which records a ca. 70 ppm mean CO2 decline at the onset of GS‐1. To address these apparent discrepancies we tested the validity of the stomatal‐based CO2 reconstructions from Kråkenes by obtaining further proxy CO2 records based on a similar approach using fossil leaves from two independent lakes in Atlantic Canada. Our Late‐glacial CO2 reconstructions reveal an abrupt ca. 77 ppm decrease in atmospheric CO2 at the onset of the Younger Dryas stadial, which lagged climatic cooling by ca. 130 yr. Furthermore, the trends recorded in the most accurate high‐resolution ice‐core record of CO2, from Dome Concordia, can be reproduced from our stomatal‐based CO2 records, when time‐averaged by the mean age distribution of air contained within Dome Concordia ice (200 to 550 yr). If correct, our results indicate an abrupt drawdown of atmospheric CO2 within two centuries at the onset of GS‐1, suggesting that some re‐evaluation of the behaviour of atmospheric CO2 sinks and sources during times of rapid climatic change, such as the Late‐glacial, may be required. Copyright © 2002 John Wiley & Sons, Ltd.
Monoclinic–orthorhombic phase transition in Ba2Cu(HCOO)6 crystals: a Raman scattering study
Authors: Paschoal C. W. A. , Ayala A. P. , Guedes I. , Freire P. T. C. , Melo F. E. A. , Mendes Filho J. , Leyva A. G. , Polla G. , Vega D. , Perazzo P. K. 
Published: January 2005

AbstractThe monoclinic–orthorhombic phase transition in Ba2Cu(HCOO)6 crystals, which takes place when the temperature is raised from 300 to 317 K, was analysed in the light of Raman scattering measurements. The disappearance of two modes related to HCOO vibrations is interpreted as the signature of phase transformation which is characterized by slight modifications in the atomic positions of HCOO in the unit cell. For the sake of completeness, we also show the evolution of the Raman spectrum from 50 to 300 K, where no phase transformation is observed. Copyright © 2002 John Wiley & Sons, Ltd.
Light and deuterated acetonitrile: an unresolved casus?
Authors: Morresi A. , Ombelli M. , Sassi P. , Santini S. 
Published: January 2005

AbstractIn spite of its high degree of symmetry and its simple structure, the physical and dynamic properties of acetonitrile are far from completely understood. In particular, the behaviour of deuterated acetonitrile does not follow the usual rules of isotopic substitution and consequently, it is not directly connected to the characteristics of the light molecule. Simple infrared and Raman experimental data on pure CH3CN and CD3CN together with isotopic and chemical equimolar mixtures the two are illustrated in detail; a qualitative interpretation is possible if it is accepted that the isotopic substitution can substantially modify the local organization of these molecular liquids. Copyright © 2002 John Wiley & Sons, Ltd.
Micro‐Raman study of iridium silicides
Authors: Almendra A. , Rodríguez A. , Rodríguez T. , Martín P. , Jiménez J. 
Published: January 2005

AbstractThe micro‐Raman spectra of three iridium silicides, IrSi, IrSi1.75 and IrSi3, were obtained. The silicides were prepared by rapid thermal annealing of iridium films deposited on Si substrates. The three phases were identified by Rutherford backscattering spectrometry. The main bands observed in the micro‐Raman spectra are described in order to provide a simple characterization method for these silicides with high spatial resolution. The three silicides present phonon bands around 165 and 200 cm−1. Some additional broad bands between 240 and 500 cm−1 were also observed. Copyright © 2002 John Wiley & Sons, Ltd.
Surface‐enhanced Raman scattering of imidazole adsorbed on an iron surface
Authors: Wang G. , Shi J. , Yang H. , Wu X. , Zhang Z. , Gu R. , Cao P. 
Published: January 2005

AbstractThe adsorption of imidazole on a roughened polycrystalline iron electrode was investigated by the SERS technique at pH values of neutral, 11 and 14 and compared with those from each solution. The results indicated that imidazole was adsorbed as mainly the neutral form and/or a certain amount of ylide form on the Fe surface in a neutral solution. The molecules have maximum adsorption at −0.9 V potential with tilted or perpendicular orientation with respect to the Fe surface, whereas a face‐on orientation of imidazole was favored at both more cathodic and anodic potentials. In a weaker basic solution imidazole was also adsorbed on the Fe surface as the neutral form, and took a face‐on orientation with respect to the Fe surface at all measured potentials because of its weaker adsorption than that in a neutral solution. Neutral and anionic forms of imidazole on the Fe surface were indicated by SERS at pH 14. Copyright © 2002 John Wiley & Sons, Ltd.