bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dehydroepiandrosterone sulfate and estrone sulfate reduce GABA‐recurrent inhibition in the hippocampus via muscarinic acetylcholine receptors
Authors: Steffensen Scott C. , Jones Marc D. , Hales Kimberly , Allison David W. 
Published: October 2006

AbstractSeveral recent studies have established a role for estrogens in ameliorating specific neurodegenerative disorders, mainly those associated with the cholinergic neurons of the basal forebrain and their targets in the cortex and hippocampus. We have previously demonstrated that endogenous and exogenous application of the neurosteroid dehydroepiandrosterone sulfate (DHEAS) markedly reduces GABA‐mediated recurrent inhibition and synchronizes hippocampal unit activity to theta rhythm (Steffensen (1995) Hippocampus 5:320–328). In this study, we evaluated the role of muscarinic receptors in mediating the effects of DHEAS and estrone sulfate (ES), the principal circulating estrogen in humans, on short‐latency‐evoked potential responses, paired‐pulse inhibition (PPI), paired‐pulse facilitation, and GABA interneuron activity in the dentate gyrus and CA1 subfields of the rat hippocampus. In situ microelectrophoretic application of the muscarinic M2 subtype cholinergic receptor agonist cis‐dioxolane, DHEAS, and ES markedly reduced PPI in the dentate and CA1 that was blocked by the M2 receptor antagonist gallamine. Similar to DHEAS, microelectrophoretic administration of ES increased population spike amplitudes, without increasing excitatory transmission, but this effect was not blocked by gallamine. Microelectrophoretic application of cis‐dioxolane and ES markedly increased the firing rate of dentate hilar interneurons and CA1 oriens/alveus interneurons and enhanced their synchrony to hippocampal theta rhythm. These findings suggest that select GABA‐modulating neurosteroids and neuroactive estrogen sulfates alter septohippocampal cholinergic modulation of hippocampal GABAergic interneurons mediating recurrent, but not feedforward, inhibition of hippocampal principal cell activity. © 2006 Wiley‐Liss, Inc.
London taxi drivers and bus drivers: A structural MRI and neuropsychological analysis
Authors: Maguire Eleanor A. , Woollett Katherine , Spiers Hugo J. 
Published: October 2006

AbstractLicensed London taxi drivers show that humans have a remarkable capacity to acquire and use knowledge of a large complex city to navigate within it. Gray matter volume differences in the hippocampus relative to controls have been reported to accompany this expertise. While these gray matter differences could result from using and updating spatial representations, they might instead be influenced by factors such as self‐motion, driving experience, and stress. We examined the contribution of these factors by comparing London taxi drivers with London bus drivers, who were matched for driving experience and levels of stress, but differed in that they follow a constrained set of routes. We found that compared with bus drivers, taxi drivers had greater gray matter volume in mid‐posterior hippocampi and less volume in anterior hippocampi. Furthermore, years of navigation experience correlated with hippocampal gray matter volume only in taxi drivers, with right posterior gray matter volume increasing and anterior volume decreasing with more navigation experience. This suggests that spatial knowledge, and not stress, driving, or self‐motion, is associated with the pattern of hippocampal gray matter volume in taxi drivers. We then tested for functional differences between the groups and found that the ability to acquire new visuo‐spatial information was worse in taxi drivers than in bus drivers. We speculate that a complex spatial representation, which facilitates expert navigation and is associated with greater posterior hippocampal gray matter volume, might come at a cost to new spatial memories and gray matter volume in the anterior hippocampus. © 2006 Wiley‐Liss, Inc.
How do respondents process stated choice experiments? Attribute consideration under varying information load
Authors: Hensher David A. 
Published: October 2006

AbstractThe popularity of stated choice (SC) experiments has produced many design strategies in which researchers use increasingly more ‘complex’ choice settings to study choice behaviour. When the amount of information to assess increases, we wonder how an individual handles such information in making a choice. Defining the amount of information as the number of attributes associated with each choice set, we investigate how this information is processed as we vary its ‘complexity’. Four ordered heterogeneous logit models are developed, each for an SC design based on a fixed number of attributes, in which the dependent variable defines the number of attributes that are ignored. We find that the degree to which individuals ignore attributes is influenced by the dimensionality of the SC experiment, the deviation of attribute levels from an experienced reference alternative, the use of ‘adding up’ attributes where feasible, the number of choice sets evaluated, and the personal income of the respondent. The empirical evidence supports the view that individuals appear to adopt a range of ‘coping’ strategies that are consistent with how they process information in real markets, and that aligning ‘choice complexity’ with the amount of information to process is potentially misleading. Relevancy is what matters. Copyright © 2006 John Wiley & Sons, Ltd.
How quickly do forecasters incorporate news? Evidence from cross‐country surveys
Authors: Isiklar Gultekin , Lahiri Kajal , Loungani Prakash 
Published: October 2006

AbstractUsing forecasts from Consensus Economics Inc., we provide evidence on the efficiency of real GDP growth forecasts by testing whether forecast revisions are uncorrelated. As the forecast data used are multi‐dimensional—18 countries, 24 monthly forecasts for the current and the following year and 16 target years—the panel estimation takes into account the complex structure of the variance–covariance matrix due to propagation of shocks across countries and economic linkages among them. Efficiency is rejected for all 18 countries: forecast revisions show a high degree of serial correlation. We then develop a framework for characterizing the nature of the inefficiency in forecasts. For a smaller set of countries, the G‐7, we estimate a VAR model on forecast revisions. The degree of inefficiency, as manifested in the serial correlation of forecast revisions, tends to be smaller in forecasts of the USA than in forecasts for European countries. Our framework also shows that one of the sources of the inefficiency in a country's forecasts is resistance to utilizing foreign news. Thus the quality of forecasts for many of these countries can be significantly improved if forecasters pay more attention to news originating from outside their respective countries. This is particularly the case for Canadian and French forecasts, which would gain by paying greater attention than they do to news from the USA and Germany, respectively. Copyright © 2006 John Wiley & Sons, Ltd.
Mentoring special youth populations
Authors: Britner Preston A. , Balcazar Fabricio E. , Blechman Elaine A. , Blinn‐Pike Lynn , Larose Simon 
Published: October 2006

AbstractWhereas mentoring programs are well received as support services, very little empirical research has been conducted to assess the effectiveness of these programs to meet the diverse needs of different special populations of youth. Potentially useful theoretical orientations (attachment, parental acceptance‐rejection, social support, adult development, host provocation) and a sociomotivational model of mentoring are presented to complement Rhodes's (2002) model. Mentoring research literatures for five special populations of youth (abused and neglected youth, youth who have disabilities, pregnant and parenting adolescents, juvenile offenders, academically at‐risk students) are critiqued. Systemic, longitudinal research must address the cooccurrence of risk factors, populations, and interventions. We conclude with specific recommendations for future research. © 2006 Wiley Periodicals, Inc.
Community organizing and advocacy: Increasing the quality and quantity of mentoring programs
Authors: Wandersman Abraham , Clary E. Gil , Forbush Janet , Weinberger Susan G. , Coyne Shawn M. , Duffy Jennifer L. 
Published: October 2006

AbstractAlthough youth mentoring programs are widespread, it is clear that there is a great need to increase their quality and quantity. This article provides background on funding initiatives in mentoring, and the role of community organizing and advocacy in influencing the demand for programs. A model that examines the community's role in influencing and coordinating key stakeholder groups in planning, implementing, and sustaining programs is proposed. The need for more effective programs is examined in a second model, which relates the capacity of organizations, staff, and programs for training and technical assistance to the quality and efficacy of their programs. Recommendations for future research are made. © 2006 Wiley Periodicals, Inc.
Thermovoltaic properties of hornet silk
Authors: Volynchik S. , Plotkin M. , Ermakov N.Y. , Bergman D.J. , Ishay J.S. 
Published: October 2006

AbstractIn silk from the larval silk caps of the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae), temperature‐dependent changes in the electric voltage have been recorded, with rise in the voltage occurring mainly upon rise in the temperature between 10–36°C. The peak voltage was measured between 32–38°C and attained 240–360 mV, but with further increase in temperature, the voltage decreased, dropping to 0 mV at about 45–50°C. Upon second measurement (of same silk specimen), the voltage peak usually occurred later (by 8–9°C) and at higher temperature than in the first measurement. Continuous measurements during warming up to 30°C followed by cooling down to 15°C yielded an hysteresis between the warming “line” and the cooling “line”, the former often straight and the latter usually curved. Maintaining the silk specimen at a fixed temperature for a prolonged period (hours) initially causes the voltage to rise, then remain steady, and finally drop. Boiling the silk caps in tap water for 7–10 min exerts some changes in the silk properties, mainly a decrease in voltage level. The general behavior of the silk suggests that it is a polymer endowed with the qualities of an organic semiconductor. The various properties of the larval silk are discussed in great detail. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Correlation of symmetrical gaits and whole body mechanics: debunking myths in locomotor biodynamics
Authors: Biknevicius Audrone R. , Reilly Stephen M. 
Published: October 2006

AbstractIndependent maturation of gait (Hildebrand) and whole body mechanics (Cavagna et al.) traditions in locomotor analyses has led to conflicting terminology. Re‐evaluation of these traditions yields three primary insights. First, walking and running should be recognized by their fundamentally different mechanics. Because duty factor fails to consistently distinguish these mechanics, its use in discriminating walks from runs should be abandoned in preference to parameters that more accurately reflect the movements of the center of mass (COM; phase difference in external mechanical energy or Froude number). Second, “trot” should be reserved as a descriptor of a particular footfall pattern. This and all gait terms lack explicit information about limb compliance and thus COM movements. Third, symmetrical gait definitions should be broadened to reflect the four primary footfall patterns: the lateral‐couplet dominated pattern of the pace, the diagonal‐couplet dominated pattern of the trot and the more independent sequencing of footfalls of the two singlefoots. Intermediate gaits (perennially confusing and a mouthful to pronounce) are thereby subsumed by these four discrete gaits. Confusion between gait terminologies would be avoided if limb phase were consistently reported. J. Exp. Zool. 305A, 2006. © 2006 Wiley‐Liss, Inc.
De Novo Nonalcoholic Fatty Liver Disease After Liver Transplantation
Authors: Seo Suk , Maganti Kalyani , Khehra Manjit , Ramsamooj Rajendra , Tsodikov Alexander , Bowlus Christopher , McVicar John , Zern Mark , Torok Natalie 
Published: October 2006

Abstract
Hepatic steatosis is a recognized problem in patients after orthotopic liver transplant (OLT). However, de novo development of nonalcoholic fatty liver disease (NAFLD) has not been well described. The aim of this study was to determine the prevalence and predictors of de novo NAFLD after OLT. A retrospective analysis was performed on 68 OLT patients with donor liver biopsies and posttransplantation liver biopsies. Individual medical charts were reviewed for demographics, indication for OLT, serial histology reports, genotypes for hepatitis C, comorbid conditions, and medications. Liver biopsies were reviewed blindly and graded according to the Brunt Scoring System. Multivariate logistic regression analysis was used to study the risk factors for developing NAFLD. The interval time from OLT to subsequent follow-up liver biopsy was 28 ± 18 months. A total of 12 patients (18%) developed de novo NAFLD, and 6 (9%) developed de novo NASH. The regression model indicated that the use of angiotensin-converting enzyme inhibitors (ACE-I) was associated with a reduced risk of developing NAFLD after OLT (odds ratio, 0.09; 95% confidence interval, 0.010-0.92; P = 0.042). Increase in body mass index (BMI) of greater than 10% after OLT was associated with a higher risk of developing NAFLD (odds ratio, 19.38; 95% confidence interval, 3.50-107.40; P = 0.001). In conclusion, de novo NAFLD is common in the post-OLT setting, with a significant association with weight gain after transplant. The use of an ACE-I may reduce the risk of developing post-OLT NAFLD. Liver Transpl, 2006. © 2006 AASLD.
Transthyretin-Derived Amyloid Deposition on the Gastric Mucosa in Domino Recipients of Familial Amyloid Polyneuropathy Liver
Authors: Takei Yo-ichi , Gono Takahisa , Yazaki Masahide , Ikeda Shu-ichi , Ikegami Toshihiko , Hashikura Yasuhiko , Miyagawa Shin-ichi , Hoshii Yoshinobu 
Published: October 2006

Abstract

Familial amyloid polyneuropathy (FAP) is a form of hereditary generalized amyloidosis. Liver tissue explanted from FAP patients has normal structure and function, except for the production of amyloidogenic variant transthyretin (TTR), and domino liver transplantation (DLT) using grafts from FAP patients was first performed in 1995. FAP symptoms usually develop in genetically determined individuals after the age of 20, but it is difficult to estimate when FAP symptoms will appear in domino recipients. Concerning this problem, histological findings showing amyloid deposition have recently been obtained in a few domino recipients of FAP livers. This study investigated the presence of de novo amyloid deposition in the gastroduodenal mucosa of domino recipients transplanted at our institution. Biopsy of gastroduodenal mucosa was carried out in 5 recipients of FAP livers and TTR-derived amyloid deposits were detected in 2 patients, both of whom had undergone DLT 47 months previously. In FAP liver recipients, de novo systemic amyloid deposition may begin much sooner than previously supposed. Therefore, careful follow-up of domino recipients of FAP livers is required. Liver Transpl, 2006. © 2006 AASLD.
Local time and Tanaka formula for a multitype Dawson–Watanabe superprocess
Authors: López‐Mimbela José A. , Villa Morales José 
Published: October 2006

AbstractIn [3] Dynkin defined the local time of a continuous superprocess as a stochastic integral and gave a criterion for existence of local time. Here we prove that the conditions in Dynkin's existence criterion are satisfied by the multitype Dawson–Watanabe superprocess, and give a Tanaka formula‐like representation of the local time which is used to show that the occupation measure of the multitype superprocess is absolutely continuous with respect to an appropriate reference measure, and that the corresponding density coincides a.s. with the local time. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Regions of variability for convex functions
Authors: Yanagihara Hiroshi 
Published: October 2006

AbstractLet 𝒞 be the class of convex univalent functions f in the unit disc 𝔻 normalized by f (0) = f ′(0) – 1 = 0. For z 0 ∈ 𝔻 and |λ | ≤ 1 we shall determine explicitly the regions of variability {log f ′(z 0): f ∈ 𝒞, f ″(0) = 2λ }. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dirichlet regularity in arbitrary o‐minimal structures on the field ℝ up to dimension 4
Authors: Kaiser Tobias 
Published: October 2006

AbstractIn this article we show that the set of Dirichlet regular boundary points of a bounded domain of dimension up to 4, definable in an arbitrary o‐minimal structure on the field ℝ, is definable in the same structure. Moreover we give estimates for the dimension of the set of non‐regular boundary points, depending on whether the structure is polynomially bounded or not.This paper extends the results from the author's Ph.D. thesis [6, 7] where the problem was solved for polynomially bounded o‐minimal structures expanding the real field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cerebral autoregulation is preserved in multiple system atrophy: A transcranial Doppler study
Authors: Pavy‐Le Traon Anne , Hughson Richard L. , Thalamas Claire , Galitsky Monique , Fabre Nelly , Rascol Olivier , Senard Jean‐Michel 
Published: October 2006

AbstractPatients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 ± 12 yr of age) and 12 healthy volunteers (61 ± 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross‐spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross‐spectral analysis showed a phase for the mid‐frequency band (0.07–0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA. © 2006 Movement Disorder Society
Hypoperfusion of the auditory and prefrontal cortices in Parkinsonian patients with verbal hallucinations
Authors: Matsui Hideaki , Nishinaka Kazuto , Oda Masaya , Hara Narihiro , Komatsu Kenichi , Kubori Tamotsu , Udaka Fukashi 
Published: October 2006

AbstractWe examined patients with and without auditory hallucinations, using n‐isopropyl‐p‐[123I]iodoamphetamine single photon emission computed tomographic imaging. We assessed verbal hallucinations in the present study: patients with nonverbal auditory hallucinations were excluded. A total of 11 patients with verbal and visual hallucinations and 17 patients with visual hallucinations only were enrolled. Patients with both verbal and visual hallucinations revealed significant hypoperfusion in the bilateral prefrontal cortex and right superior temporal gyrus compared to patients with visual hallucinations only. There were no significant hyperperfusion in patients with verbal plus visual hallucinations. These results may support the release hallucination theory in verbal hallucinations of Parkinson's disease, although another explanations may be more appropriate and further studies are required. © 2006 Movement Disorder Society
In vivo MRI of cancer cell fate at the single‐cell level in a mouse model of breast cancer metastasis to the brain
Authors: Heyn Chris , Ronald John A. , Ramadan Soha S. , Snir Jonatan A. , Barry Andrea M. , MacKenzie Lisa T. , Mikulis David J. , Palmieri Diane , Bronder Julie L. , Steeg Patricia S. , Yoneda Toshiyuki , MacDonald Ian C. , Chambers Ann F. , Rutt Brian K. , Foster Paula J. 
Published: October 2006

AbstractMetastasis (the spread of cancer from a primary tumor to secondary organs) is responsible for most cancer deaths. The ability to follow the fate of a population of tumor cells over time in an experimental animal would provide a powerful new way to monitor the metastatic process. Here we describe a magnetic resonance imaging (MRI) technique that permits the tracking of breast cancer cells in a mouse model of brain metastasis at the single‐cell level. Cancer cells that were injected into the left ventricle of the mouse heart and then delivered to the brain were detectable on MR images. This allowed the visualization of the initial delivery and distribution of cells, as well as the growth of tumors from a subset of these cells within the whole intact brain volume. The ability to follow the metastatic process from the single‐cell stage through metastatic growth, and to quantify and monitor the presence of solitary undivided cells will facilitate progress in understanding the mechanisms of brain metastasis and tumor dormancy, and the development of therapeutics to treat this disease. Magn Reson Med, 2006. Published 2006 Wiley‐Liss, Inc.
Behavior of ordered sodium in enzymatically depleted cartilage tissue
Authors: Ling Wen , Regatte Ravinder R. , Schweitzer Mark E. , Jerschow Alexej 
Published: October 2006

AbstractThe onset of cartilage tissue disorders can be characterized by a loss of proteoglycans (PGs) and diagnosed by contrast‐enhanced proton (1H) MRI techniques, as well as sodium MRI. The behavior of sodium located in anisotropic environments, is examined as a function of cartilage degeneration. PGs are proteolytically depleted from the cartilage samples, which gives rise to a decrease of the ordered sodium content. More surprisingly, however, the residual quadrupolar couplings are shown to increase with increasing depletion levels. Since the residual quadrupolar couplings are intimately related to local order and anisotropic motion, measuring their distribution in cartilage may provide insight into the structural changes that occur within the tissue upon degradation. In this study relatively mild orientational dependence of the couplings was found. Little or no free sodium was observed in the cartilage specimens under study. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
An algorithm for the automated quantitation of metabolites in in vitro NMR signals
Authors: Reynolds Greg , Wilson Martin , Peet Andrew , Arvanitis Theodoros N. 
Published: October 2006

AbstractThe quantitation of metabolite concentrations from in vitro NMR spectra is hampered by the sensitivity of peak positions to experimental conditions. The quantitation methods currently available are generally labor intensive and cannot readily be automated. Here, an algorithm is presented for the automatic time domain analysis of high‐resolution NMR spectra. The TARQUIN algorithm uses a set of basis functions obtained by quantum mechanical simulation using predetermined parameters. Each basis function is optimized by subdividing it into a set of signals from magnetically equivalent spins and varying the simulated chemical shifts of each of these groups to match the signal undergoing analysis. A novel approach to the standard multidimensional minimization problem is introduced based on evaluating the fit resulting from different permutations of possible chemical shifts, obtained from one‐dimensional searches. Results are presented from the analysis of 1H proton magic angle spinning spectra of cell lines illustrating the robustness of the method in a typical application. Simulation was used to investigate the biggest peak shifts that can be tolerated. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.