bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phenotype of cerebellar glutamatergic neurons is altered in stargazer mutant mice lacking brain‐derived neurotrophic factor mRNA expression
Authors: Richardson Christine A. , Leitch Beulah 
Published: November 2004

AbstractBrain‐derived neurotrophic factor (BDNF) influences neuronal survival, differentiation, and maturation. More recently, its role in synapse formation and plasticity has also emerged. In the cerebellum of the spontaneous recessive mutant mouse stargazer (stg) there is a specific and pronounced deficit in BDNF mRNA expression. BDNF protein levels in the cerebellum as a whole are reduced by 70%, while in the granule cells (GCs) there is a selective and near total reduction in BDNF mRNA expression. Recently, we published data demonstrating that inhibitory neurons in the cerebella of stgs have significantly reduced levels (∼50%) of γ‐aminobutyric acid (GABA) and fewer, smaller inhibitory synapses compared to wildtype (WT) controls. Our current investigations indicate that the stargazer mutation has an even more pronounced effect on the phenotype of glutamatergic neurons in the cerebellum. There is a profound decrease in the levels of glutamate‐immunoreactivity (up to 77%) in stg compared to WT controls. The distribution profile of presynaptic vesicles is also markedly different: stgs have proportionally fewer docked vesicles and fewer vesicles located adjacent to the active zone ready to dock than WTs. Furthermore, the thickness of the postsynaptic density (PSD) at mossy fiber‐granule cell (MF‐GC) and parallel fiber‐Purkinje cell (PF‐PC) synapses is severely reduced (up to 33% less than WT controls). The number and length of excitatory synapses, however, appear to be relatively unchanged. It is possible that at least some of theses changes in phenotype are directly attributable to the lack of BDNF in the cerebellum of the stg mutant. J. Comp. Neurol. 481:145–159, 2005. © 2004 Wiley‐Liss, Inc.
Effects of the nature and concentration of substrates in aqueous solutions on the solubility of aroma compounds
Authors: Covarrubias‐Cervantes Marco , Bongard Sébastien , Champion Dominique , Voilley Andrée 
Published: November 2004

AbstractThe solubility of nine aroma compounds (acetone, 2‐butanone, 2‐hexanone, 2‐octanone, ethyl acetate, ethyl butanoate, ethyl hexanoate, n‐hexanal, and n‐hexanol) in both water and various aqueous solutions was measured at 25 °C using the mutual solubility method. The aqueous solutions consisted of sucrose, glucose, sorbitol, glycerol, polyethylene glycol 200, or maltodextrins at different concentrations. Aroma solubility in water decreased with increased hydrophobicity. For aroma molecules which have the same number of carbon atoms in their structure, aqueous solubility decreased as follows: aldehyde > methyl ketone > alcohol > ethyl ester. When using a group contribution method, the estimated solubility of ethyl esters and methyl ketones in water was, respectively, underestimated and overestimated. Compared to water, the solubility of the volatile molecules in aqueous solutions was higher in the aqueous polyols solutions than in the carbohydrate solutions, although solubility decreased as substrate concentration increased. Aqueous solutions properties, such as water activity, also inﬂuenced aroma compound solubility. Copyright © 2004 John Wiley & Sons, Ltd.
Process Simulation for Molten Carbonate Fuel Cells
Authors: Fermeglia M. , Cudicio A. , DeSimon G. , Longo G. , Pricl S. 
Published: November 2004

AbstractIn the framework of electricity production from molten carbonate fuel cells (MCFC), this work presents the results obtained from steady state process simulation, coupled with a detailed dynamic model for the cell. The derivation of the model is briefly outlined, and detailed results of the simulation are reported. Macroscopic state variables of the overall system process are investigated by means of sensitivity analysis, yielding clear directions for process improvement and optimisation. The detailed steady state and dynamic simulation of the MCFC for a bi‐dimensional cross flow configuration showed the importance of the state variable distribution in the cell. Both models were based on data from real plants, and the simulation conditions were selected according to real operating conditions. The process studied was a 500 kW MCFC power system based on Ansaldo fuel cell (AFC) technology. The steady state simulation revealed the main interactions among the different devices involved in the process, and the subsequent sensitivity analysis showed that there is room for improvement in electrical efficiency by increasing: i) the steam to methane ratio, ii) the pressure, and iii) the air feed ratio. The dynamic simulation yielded the quantitative response of the system to several, different, perturbations and proved to be a valid tool for determining temperature, current, and voltage profiles as a function of time, within the fuel cells.
Influence of Summer Drought on Spatial Patterns of Resource Availability and Detritus Processing in Mediterranean Stream Sub‐Basins (Sardinia, Italy)
Authors: Pinna Maurizio , Fonnesu Alessio , Sangiorgio Franca , Basset Alberto 
Published: November 2004

AbstractWe studied the variation patterns of Phragmites australis detritus decomposition and derived patterns of field resource availability in three Mediterranean‐type sub‐basins exposed to varying degrees to summer drought events. The study was carried out during spring‐summer 1998 and fall‐winter 1998–1999, in 1st to 4th order streams. Detritus processing and macroinvertebrate body‐condition were measured. Decomposition rates were significantly higher in spring‐summer than in fall‐winter, in relatively unper turbed than in perturbed sub‐basins, and in high‐order than low‐order streams. The influence of disturbance decreased with increasing stream order, suggesting that higher order streams have greater resilience to drought events than lower order streams. The body condition of macroinvertebrates suggested patterns of field resource availability spatially covariant with those of detritus decay and ecosystem resilience. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Endocrine response to fasting in the overwintering captive raccoon dog (Nyctereutes procyonoides)
Authors: nieminen Petteri , Saarela Seppo , Pyykönen Teija , Asikainen Juha , Mononen Jaakko , Mustonen Anne‐Mari 
Published: November 2004

AbstractThe raccoon dog (Nyctereutes procyonoides) is an omnivorous canid utilizing the passive wintering strategy in the boreal climate. Farmed raccoon dogs (n=12) were randomly assigned into two study groups on 26 November 2003. Between 3 December 2003 and 27 January 2004, half of the animals were fasted for 8 weeks and plasma weight‐regulatory hormone concentrations determined on 26 November and 30 December 2003 and on 27 January 2004. The plasma peptide YY, ghrelin, and growth hormone (GH) concentrations increased due to food deprivation, while the T4 and Acrp30 concentrations decreased. Furthermore, the plasma GH concentrations were higher in the fasted raccoon dogs than in the fed animals, which had higher plasma insulin, glucagon, and T4 concentrations. However, fasting had no effect on the plasma leptin concentrations. The results confirm previous findings with unchanged leptin levels in fasting carnivores. Increased GH levels probably contribute to increased lipolysis and mobilization of fat stores. Ghrelin can also enhance lipolysis by increasing the GH levels. The decreased levels of T4 may reduce the metabolic rate. The plasma dopamine concentrations decreased due to fasting unlike observed previously in rats. Together with the unaffected adrenaline, noradrenaline, and cortisol concentrations, this suggests that food deprivation in winter does not cause stress to the raccoon dog but is an integral part of its natural life history. J. Exp. Zool. 301A:919–929, 2004. © 2004 Wiley‐Liss, Inc.
In vivo visualization of Alzheimer's amyloid plaques by magnetic resonance imaging in transgenic mice without a contrast agent
Authors: Jack Clifford R. , Garwood Michael , Wengenack Thomas M. , Borowski Bret , Curran Geoffrey L. , Lin Joseph , Adriany Gregor , Gröhn Olli H. J. , Grimm Roger , Poduslo Joseph F. 
Published: November 2004

AbstractOne of the cardinal pathologic features of Alzheimer's disease (AD) is the formation of senile, or amyloid, plaques. Transgenic mice have been developed that express one or more of the genes responsible for familial AD in humans. Doubly transgenic mice develop “human‐like” plaques, providing a mechanism to study amyloid plaque biology in a controlled manner. Imaging of labeled plaques has been accomplished with other modalities, but only MRI has sufficient spatial and contrast resolution to visualize individual plaques noninvasively. Methods to optimize visualization of plaques in vivo in transgenic mice at 9.4 T using a spin echo sequence based on adiabatic pulses are described. Preliminary results indicate that a spin echo acquisition more accurately reflects plaque size, while a T2* weighted gradient echo sequence reflects plaque iron content, not plaque size. In vivo MRI–ex vivo MRI–in vitro histologic correlations are provided. Histologically verified plaques as small as 50 μm in diameter were visualized in living animals. To our knowledge this work represents the first demonstration of noninvasive in vivo visualization of individual AD plaques without the use of a contrast agent. Magn Reson Med 52:1263–1271, 2004. © 2004 Wiley‐Liss, Inc.
Measurement and correction of respiration‐induced B0 variations in breast 1H MRS at 4 Tesla
Authors: Bolan Patrick J. , Henry Pierre‐Gilles , Baker Eva H. , Meisamy Sina , Garwood Michael 
Published: November 2004

AbstractRespiratory motion is well known to cause artifacts in magnetic resonance spectroscopy (MRS). In MRS of the breast, the dominant artifact is not due to motion of the breast itself, but rather it is produced by B0 field distortions associated with respiratory motion of tissues in the chest and abdomen. This susceptibility artifact has been reported to occur in the brain, but it is more apparent in the breast due to the anatomic proximity of the lungs. In the breast, these B0 distortions cause shot‐to‐shot frequency shifts, which vary an average of 24 Hz during a typical 1H MRS scan at 4 T. This variation can be corrected retrospectively by frequency shifting individual spectra prior to averaging. If not corrected, these shifts reduce spectral resolution and increase peak fitting errors. This work demonstrates the artifact, describes a method for correcting it, and evaluates its impact on quantitative spectroscopy. When the artifact is not corrected, quantification errors increase by an average of 28%, which dramatically impacts the ability to measure metabolite resonances at low signal‐to‐noise ratios. Magn Reson Med 52:1239–1245, 2004. © 2004 Wiley‐Liss, Inc.
Experimental application of thermosensitive paramagnetic liposomes for monitoring magnetic resonance imaging guided thermal ablation
Authors: Frich Lars , Bjørnerud Atle , Fossheim Sigrid , Tillung Terje , Gladhaug Ivar 
Published: November 2004

AbstractThe use of a liposomal paramagnetic agent with a T1‐relaxivity that increases markedly at temperatures above the phase transition temperature (Tm) of the liposomal membrane was evaluated during magnetic resonance imaging (MRI) guided hyperthermia ablation. A neodymium‐yttrium aluminum garnet (Nd‐YAG) laser unit and a radiofrequency ablation system were used for tissue ablation in eight rabbit livers in vivo. One ablation was made in each animal prior to administration of the liposomal agent. Liposomes with a Tm of 57°C containing gadodiamide (GdDTPA‐BMA) were injected iv, and two additional ablations were performed. T1‐weighted scans were performed in heated tissue, after tissue temperature had normalized, and 15–20 min after normalization of tissue temperature. Increase in signal intensity (ΔSI) for ablations prior to injection of the agent was 13.0% (SD = 5.7) for the laser group and 9.1% (SD = 7.9) for the radiofrequency group. Signal intensity after administration of the agent unrelated to heating was not statistically significant (ΔSI = 1.4%, P = 0.35). For ablations made after injection of the agent, a significant increase was found in the laser (ΔSI = 34.5%, SD = 11.9) and radiofrequency group (ΔSI = 21.6%, SD = 22.7). The persistent signal enhancement found in areas exposed to a temperature above the threshold temperature above Tm allows thermal monitoring of MRI guided thermal ablation. Magn Reson Med 52:1302–1309, 2004. © 2004 Wiley‐Liss, Inc.
Simultaneous MRI acquisition of blood volume, blood flow, and blood oxygenation information during brain activation
Authors: Yang Yihong , Gu Hong , Stein Elliot A. 
Published: November 2004

AbstractSimultaneous acquisition of complementary functional hemodynamic indices reflecting different aspects of brain activity would be a valuable tool for functional brain‐imaging studies offering enhanced detection power and improved data interpretation. As such, a new MRI technique is presented that is able to achieve concurrent acquisition of three hemodynamic images based primarily on the changes of cerebral blood volume, blood flow, and blood oxygenation, respectively, associated with brain activation. Specifically, an inversion recovery pulse sequence has been designed to measure VASO (vascular space occupancy), ASL (arterial spin labeling) perfusion, and BOLD (blood‐oxygenation‐level‐dependent) signals in a single scan. The MR signal characteristics in this sequence were analyzed, and image parameters were optimized for the simultaneous acquisition of these functional images. The feasibility and efficacy of the new technique were assessed by brain activation experiments with visual stimulation paradigms. Experiments on healthy volunteers showed that this technique provided efficient image acquisition, and thus higher contrast‐to‐noise ratio per unit time, compared with conventional techniques collecting these functional images separately. In addition, it was demonstrated that the proposed technique was able to be utilized in event‐related functional MRI experiments, with potential advantages of obtaining accurate transient information of the activation‐induced hemodynamic responses. Magn Reson Med 52:1407–1417, 2004. Published 2004 Wiley‐Liss, Inc.
A generalized affine gap model significantly improves protein sequence alignment accuracy
Authors: Zachariah Marcus A. , Crooks Gavin E. , Holbrook Stephen R. , Brenner Steven E. 
Published: November 2004

AbstractSequence alignment underpins common tasks in molecular biology, including genome annotation, molecular phylogenetics, and homology modeling. Fundamental to sequence alignment is the placement of gaps, which represent character insertions or deletions. We assessed the ability of a generalized affine gap cost model to reliably detect remote protein homology and to produce high‐quality alignments. Generalized affine gap alignment with optimal gap parameters performed as well as the traditional affine gap model in remote homology detection. Evaluation of alignment quality showed that the generalized affine model aligns fewer residue pairs than the traditional affine model but achieves significantly higher per‐residue accuracy. We conclude that generalized affine gap costs should be used when alignment accuracy carries more importance than aligned sequence length. Proteins 2005. © 2004 Wiley‐Liss, Inc.
Role of the electronic properties of azurin active site in the electron‐transfer process
Authors: Corni Stefano , De Rienzo Francesca , Di Felice Rosa , Molinari Elisa 
Published: November 2004

AbstractElectron transfer proteins, such as azurin (a blue copper protein), are promising candidates for the implementation of biomolecular nanoelectronic devices. To understand the details of electron transfer in redox active azurin molecules, we performed plane‐wave pseudo‐potential density functional theory (DFT) calculations of the protein active site in the two possible oxidation states Cu(I) and Cu(II). The ab initio results are used to discuss how the electronic spectrum and wavefunctions may mediate the shuttling of electrons through the copper ion. We find that the Cu‐ligand hybridization is very similar in the two charge states of the metal center, but the energy spectrum changes substantially. This result might indicate important effects of electronic correlations in the redox activity and consequent electron transfer through the Cu site. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Response of zooplankton to nutrient enrichment and fish in shallow lakes: a pan‐European mesocosm experiment
Authors: Vakkilainen Kirsi , Kairesalo Timo , Hietala Jaana , Balayla David M. , Bécares Eloy , Van de Bund Wouter J. , Van Donk Ellen , Fernández‐Aláez Margarita , Gyllström Mikael , Hansson Lars‐Anders , Miracle Maria R. , Moss Brian , Romo Susana , Rueda Juan , Stephen Deborah 
Published: November 2004

Summary1. Responses of zooplankton to nutrient enrichment and fish predation were studied in 1998 and 1999 by carrying out parallel mesocosm experiments in six lakes across Europe.2. Zooplankton community structure, biomass and responses to nutrient and fish manipulation showed geographical and year‐to‐year differences. Fish had a greater influence than nutrients in regulating zooplankton biomass and especially the relative abundances of different functional groups of zooplankton. When fish reduced the biomass of large crustaceans, there was a complementary increase in the biomasses of smaller crustacean species and rotifers.3. High abundance of submerged macrophytes provided refuge for zooplankton against fish predation but this refuge effect differed notably in magnitude among sites.4. Large crustacean grazers (Daphnia, Diaphanosoma, Sida and Simocephalus) were crucial in controlling algal biomass, while smaller crustacean grazers and rotifers were of minor importance. Large grazers were able to control phytoplankton biomass even under hypereutrophic conditions (up to 1600 μg TP L−1) when grazer biomass was high (>80–90 μg dry mass L−1) or accounted for >30% of the grazer community.5. The littoral zooplankton community was less resistant to change following nutrient enrichment in southern Spain, at high temperatures (close to 30 °C), than at lower temperatures (17–23 °C) characterising the other sites. This lower resistance was because of a greater importance of nutrients than zooplankton in controlling algal biomass.6. Apart from the reduced role of large crustacean grazers at the lowest latitude, no consistent geographical patterns were observed in the responses of zooplankton communities to nutrient and fish manipulation.
Responses of phytoplankton to fish predation and nutrient loading in shallow lakes: a pan‐European mesocosm experiment
Authors: Van De Bund W. J. , Romo S. , Villena M. J. , Valentín M. , Van Donk E. , Vicente E. , Vakkilainen K. , Svensson M. , Stephen D. , Ståhl‐Delbanco A. , Rueda J. , Moss B. , Miracle M. R. , Kairesalo T. , Hansson L.‐A. , Hietala J. , Gyllström M. , Goma J. , García P. , Fernández‐Aláez M. , Fernández‐Aláez C. , Ferriol C. , Collings S. E. , Bécares E. , Balayla D. M. , Alfonso T. 
Published: November 2004

Summary1. The impacts of nutrients (phosphorus and nitrogen) and planktivorous fish on phytoplankton composition and biomass were studied in six shallow, macrophyte‐dominated lakes across Europe using mesocosm experiments.2. Phytoplankton biomass was more influenced by nutrients than by densities of planktivorous fish. Nutrient addition resulted in increased algal biomass at all locations. In some experiments, a decrease was noted at the highest nutrient loadings, corresponding to added concentrations of 1 mg L−1 P and 10 mg L−1 N.3. Chlorophyll a was a more precise parameter to quantify phytoplankton biomass than algal biovolume, with lower within‐treatment variability.4. Higher densities of planktivorous fish shifted phytoplankton composition toward smaller algae (GALD < 50 μm). High nutrient loadings selected in favour of chlorophytes and cyanobacteria, while biovolumes of diatoms and dinophytes decreased. High temperatures also may increase the contribution of cyanobacteria to total phytoplankton biovolume in shallow lakes.
A Multinational Perspective on Capital Structure Choice and Internal Capital Markets
Authors: DESAI MIHIR A. , FOLEY C. FRITZ , HINES JAMES R. 
Published: November 2004

ABSTRACTThis paper analyzes the capital structures of foreign affiliates and internal capital markets of multinational corporations. Ten percent higher local tax rates are associated with 2.8% higher debt/asset ratios, with internal borrowing being particularly sensitive to taxes. Multinational affiliates are financed with less external debt in countries with underdeveloped capital markets or weak creditor rights, reflecting significantly higher local borrowing costs. Instrumental variable analysis indicates that greater borrowing from parent companies substitutes for three‐quarters of reduced external borrowing induced by capital market conditions. Multinational firms appear to employ internal capital markets opportunistically to overcome imperfections in external capital markets.
Does Stock Return Momentum Explain the “Smart Money” Effect?
Authors: SAPP TRAVIS , TIWARI ASHISH 
Published: November 2004

ABSTRACTDoes the “smart money” effect documented by Gruber (1996) and Zheng (1999) reflect fund selection ability of mutual fund investors? We examine the finding that investors are able to predict mutual fund performance and invest accordingly. We show that the smart money effect is explained by the stock return momentum phenomenon documented by Jegadeesh and Titman (1993). Further evidence suggests investors do not select funds based on a momentum investing style, but rather simply chase funds that were recent winners. Our finding that a common factor in stock returns explains the smart money effect offers no affirmation of investor fund selection ability.
Price Discovery in the U.S. Treasury Market: The Impact of Orderflow and Liquidity on the Yield Curve
Authors: BRANDT MICHAEL W. , KAVAJECZ KENNETH A. 
Published: November 2004

ABSTRACTWe examine the role of price discovery in the U.S. Treasury market through the empirical relationship between orderflow, liquidity, and the yield curve. We find that orderflow imbalances (excess buying or selling pressure) account for up to 26% of the day‐to‐day variation in yields on days without major macroeconomic announcements. The effect of orderflow on yields is permanent and strongest when liquidity is low. All of the evidence points toward an important role of price discovery in understanding the behavior of the yield curve.