bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subicular and CA1 hippocampal projections to the accessory olfactory bulb
Authors: de la Rosa‐Prieto C. , Ubeda‐Banon I. , Mohedano‐Moriano A. , Pro‐Sistiaga P. , Saiz‐Sanchez D. , Insausti R. , Martinez‐Marcos A. 
Published: September 2008

AbstractThe hippocampal formation is anatomically and functionally related to the olfactory structures especially in rodents. The entorhinal cortex (EC) receives afferent projections from the main olfactory bulb; this constitutes an olfactory pathway to the hippocampus. In addition to the olfactory system, most mammals possess an accessory olfactory (or vomeronasal) system. The relationships between the hippocampal formation and the vomeronasal system are virtually unexplored. Recently, a centrifugal projection from CA1 to the accessory olfactory bulb has been identified using anterograde tracers. In the study reported herein, experiments using anterograde tracers confirm this projection, and injections of retrograde tracers show the distribution and morphology of a population of CA1 and ventral subicular neurons projecting to the accessory olfactory bulb of rats. These results extend previous descriptions of hippocampal projections to the accessory olfactory bulb by including the ventral subiculum and characterizing the morphology, neurochemistry (double labeling with somatostatin), and distribution of such neurons. These data suggest feedback hippocampal control of chemosensory stimuli in the accessory olfactory bulb. Whether this projection processes spatial information on conspecifics or is involved in learning and memory processes associated with chemical stimuli remains to be elucidated. © 2008 Wiley‐Liss, Inc.
Developmental changes in short‐term facilitation are opposite at temporoammonic synapses compared to Schaffer collateral synapses onto CA1 pyramidal cells
Authors: Speed Haley E. , Dobrunz Lynn E. 
Published: September 2008

AbstractCA1 pyramidal neurons receive two distinct excitatory inputs that are each capable of influencing hippocampal output and learning and memory. The Schaffer collateral (SC) input from CA3 axons onto the more proximal dendrites of CA1 is part of the trisynaptic circuit, which originates in Layer II of the entorhinal cortex (EC). The temporoammonic (TA) pathway to CA1 provides input directly from Layer III of the EC onto the most distal dendrites of CA1 pyramidal cells, and is involved in spatial memory and memory consolidation. We have previously described a developmental decrease in short‐term facilitation from juvenile (P13–18) to young adult (P28–42) rats at SC synapses that is due to feedback inhibition via synaptically activated mGluR1 on CA1 interneurons. It is not known how short‐term changes in synaptic strength are regulated at TA synapses, nor is it known how short‐term plasticity is balanced at SC and TA inputs during development. Here we describe a novel developmental increase in short‐term facilitation at TA synapses, which is the opposite of the decrease in facilitation occurring at SC synapses. Although short‐term facilitation is much lower at TA synapses when compared with SC synapses in juveniles, short‐term plasticity at SC and TA synapses converges at similar levels of paired‐pulse facilitation in the young adult rat. However, in young adults CA3‐CA1 synapses still exhibit more facilitation than TA‐CA1 synapses during physiologically‐relevant activity, suggesting that the two pathways are each poised to uniquely modulate CA1 output in an activity‐dependent manner. Finally, we show that there is a developmental decrease in the initial release probability at TA synapses that underlies their developmental decrease in facilitation, but no developmental change in release probability at SC synapses. This represents a fundamental difference inthe presynaptic function of the two major inputs to CA1, which could alter the flow of information in hippocampus during development. © 2008 Wiley‐Liss, Inc.
Market fundamentals versus rational bubbles in stock prices: a Bayesian perspective
Authors: Balke Nathan S. , Wohar Mark E. 
Published: September 2008

AbstractUsing Bayesian Markov chain Monte Carlo methods, we decompose the log price‐dividend ratio into a market fundamentals component and a bubble component. The market fundamentals component depends on expectations of future dividend growth and required returns, while the bubble component is assumed to follow a Markov switching model that allows for the possibility of exploding and collapsing regimes. If prior beliefs allow for the possibility of persistent shocks to dividend growth and/or required returns, the posterior distribution suggests the bubble component contributes virtually nothing to the stock price movements over our sample. On the other hand, if one's priors rule out the possibility of persistent shocks to dividend growth and required returns, the bubble component can have a much larger role to play in stock price movements. However, the regime switching behavior of the bubble bears little resemblance to infrequent switching from an exploding bubble regime to a collapsing or dormant bubble regime. Copyright © 2008 John Wiley & Sons, Ltd.
In vivo murine model of continuous intramedullary infusion of particles—A preliminary study
Authors: Ma Ting , Ortiz Steven G. , Huang Zhinong , Ren Peigen , Smith R. Lane , Goodman Stuart B. 
Published: September 2008

AbstractContinued production of wear debris affects both initial osseointegration and subsequent bone remodeling of total joint replacements (TJRs). However, continuous delivery of clinically relevant particles using a viable, cost effective, quantitative animal model to simulate the scenario in humans has been a challenge for orthopedic researchers. In this study, we successfully infused blue‐dyed polystyrene particles, similar in size to wear debris in humans, to the intramedullary space of the mouse femur for 4 weeks using an osmotic pump. Approximately 40% of the original particle load (85 μL) was delivered into the intramedullary space, an estimate of 3 × 109 particles. The visible blue dye carried by the particles confirmed the delivery. This model demonstrated that continuous infusion of particles to the murine bone‐implant interface is possible. In vivo biological processes associated using wear debris particles can be studied using this new animal model. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Mechanical performance of electron‐beam‐irradiated UHMWPE in vacuum and in air
Authors: Visco A. M. , Torrisi L. , Campo N. , Emanuele U. , Trifirò A. , Trimarchi M. 
Published: September 2008

AbstractUltrahigh molecular weight polyethylene (UHMWPE) was modified by a 5‐MeV energy electron beam at different temperatures before, during, and after irradiation, both in air and in high vacuum. Wear resistance, hardness, and tensile strength of irradiated polyethylene were compared with those of untreated one. Physical analyses (like infrared spectroscopy and calorimetric analysis) were carried out to investigate about the changes in the material induced by irradiation. Experimental results suggested that structural changes (double bonds, crosslinks, and oxidized species formation) occur in the polymer depending on the environmental conditions of the irradiation. Mechanical behavior is related to the structural modifications. A temperature of 110°C before, during, and after the in vacuum irradiation of UHMWPE produces a high amount of crosslinks and improves polymeric tensile and wear resistance, compared to that of the untreated material. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Cell therapy for bone regeneration—Bench to bedside
Authors: Lee Kevin , Chan Casey K. , Patil Nilesh , Goodman Stuart B. 
Published: September 2008

AbstractThe concept of bone tissue engineering, which began in the early 1980s, has seen tremendous growth in the numbers of research studies. One of the key areas of research has been in the field of mesenchymal stem cells, where the challenge is to produce the perfect tissue‐engineered bone construct. This practical review summarizes basic and applied state‐of‐the‐art research in the area of mesenchymal stem cells, and highlights the important translational research that has already been initiated. The topics that will be covered include the sources of stem cells in use, scaffolds, gene therapy, clinical applications in nonunions, tumors, osteonecrosis, revision arthroplasties, and spine fusion. Although significant challenges remain, there exists an exceptional opportunity to translate basic research in mesenchymal stem cell technologies into viable clinical treatments for bone regeneration. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Drug controlled release from structured bioresorbable films used in medical devices—A mathematical model
Authors: Zilberman Meital , Malka Alon 
Published: September 2008

AbstractA mathematical model for predicting drug release profiles from structured bioresorbable films was developed and studied. These films, which combine good mechanical properties with desired drug release profiles, are designed for use in various biomedical applications. Our structured polymer/drug films are prepared using a promising technique for controlling the drug location/dispersion in the film. The present model was used for predicting drug release profiles from two film types that is films in which the drug is located on the surface (A‐type) and films in which the drug is located in the bulk (B‐type). The model is based on Fick's 2nd law of diffusion and assumes that the drug release profile from the films is affected by the host polymer's characteristics, the drug location/dispersion in the film and the drug's characteristics. This semiempirical model uses the weight loss profile of the host polymers as well as the change in their degree of crystallinity with degradation. Our study indicates that the model correlates well with in vitro release results, exhibiting a mean error of less than 7% for most studied cases. It also shows that the host polymer's degradation has a greater effect on the drug release profile than the degree of crystallinity. This new model exhibits a potential for simulating the release profile of bioactive agents from structured films for a wide variety of biomedical applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Biodegradable poly(ester amine) based on glycerol dimethacrylate and polyethylenimine as a gene carrier
Authors: Arote Rohidas B. , Hwang Soon‐Kyung , Yoo Mi‐Kyong , Jere Dhananjay , Jiang Hu‐Lin , Kim You‐Kyoung , Choi Yun‐Jai , Nah Jae‐Woon , Cho Myung‐Haing , Cho Chong‐Su 
Published: September 2008

AbstractBackgroundPolyethylenimine (PEI) vectors are widely used in gene delivery because of their high transfection efficiency owing to a unique proton sponge effect. An increase in molecular weight increases transfection efficiency, but simultaneously results in increased toxicity. Therefore, the design and synthesis of new degradable gene delivery carriers having high transfection efficiencies and reduced cytotoxicity are necessary.MethodsIn the present study degradable poly(ester amines) (PEAs) based on glycerol dimethacrylate (GDM) and low molecular weight branched polyethylenimine (LMW‐PEI) were synthesized in anhydrous methanol at 60 °C following Michael addition reaction. The transfection efficiencies of the synthesized PEA/DNA complexes were evaluated using three different cell lines (HeLa, HepG2 and 293T cells) in vitro.ResultsPEAs with zeta potential in the range of 30–55 mV (at physiological pH) condensed plasmid DNA into nanosized particles (<150 nm) suitable for intracellular delivery. The PEAs degraded in a controlled fashion (t1/2 of approximately 9–10 days). Compared with PEI 25K, the PEAs showed significantly lower cytotoxicity in three different cells. The PEAs demonstrated much higher transfection efficiency compared to conventional PEI 25K and Lipofectamine. The PEA synthesized using a 1 : 4 mole ratio of GDM to PEI [GDM/PEI‐1.2 (1 : 4)] showed the highest transfection efficiency in HepG2 cells. Significantly higher pEGFP‐N2 reporter gene expression in 293T cells was achieved using these PEAs. The hyperosmotic effect of PEAs was demonstrated by the reduction in packed cell volume (PCV). The GDM/PEI‐1.2 (1 : 4) showed comparable reduction in PCV with respect to glycerol in 293T cells. The effect of bafilomycin A1 on transfection efficiency of PEAs on 293T cells indicated its endosomal buffering capacity.ConclusionsWe hypothesized that the higher transfection efficiency of PEAs was the synergistic effect arising from hyperosmotic glycerol and endosomal buffering capacity of PEAs resulting from the presence of a glycerol backbone and PEI amine groups, respectively. Copyright © 2008 John Wiley & Sons, Ltd.
Morphometric and ultrastructural comparison of the olfactory system in elasmobranchs: The significance of structure–function relationships based on phylogeny and ecology
Authors: Schluessel Vera , Bennett Michael B. , Bleckmann Horst , Blomberg Simon , Collin Shaun P. 
Published: September 2008

AbstractThis study investigated the relationship between olfactory morphology, habitat occupancy, and lifestyle in 21 elasmobranch species in a phylogenetic context. Four measures of olfactory capability, that is, the number of olfactory lamellae, the surface area of the olfactory epithelium, the mass of the olfactory bulb, and the mass of the olfactory rosette were compared between individual species and groups, comprised of species with similar habitat and/or lifestyle. Statistical analyses using generalized least squares phylogenetic regression revealed that bentho‐pelagic sharks and rays possess significantly more olfactory lamellae and larger sensory epithelial surface areas than benthic species. There was no significant correlation between either olfactory bulb or rosette mass and habitat type. There was also no significant difference between the number of lamellae or the size of the sensory surface area in groups comprised of species with similar diets, that is, groups preying predominantly on crustaceans, cephalopods, echinoderms, polychaetes, molluscs, or teleosts. However, some groups had significantly larger olfactory bulb or rosette masses than others. There was little evidence to support a correlation between phylogeny and morphology, indicating that differences in olfactory capabilities are the result of functional rather than phylogenetic adaptations. All olfactory epithelia exhibited microvilli and cilia, with microvilli in both nonsensory and sensory areas, and cilia only in sensory areas. Cilia over the sensory epithelia originated from supporting cells. In contrast to teleosts, which possess ciliated and microvillous olfactory receptor types, no ciliated olfactory receptor cells were observed. This is the first comprehensive study comparing olfactory morphology to several aspects of elasmobranch ecology in a phylogenetic context. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
Qucs: A GPL software package for circuit simulation, compact device modelling and circuit macromodelling from DC to RF and beyond
Authors: Brinson M. E. , Jahn S. 
Published: September 2008

AbstractThe ‘Quite universal circuit simulator’ (Qucs) is an open source circuit simulator supporting Verilog‐A compact model standardization. This paper describes a number of compact semiconductor device and circuit macromodelling techniques that have been implemented in recent Qucs releases, stressing those techniques that are not found in SPICE 2g6 or 3f5. It also introduces a novel hierarchical approach to Verilog‐A compact model and circuit macromodel construction based on non‐linear equation‐defined devices, linear‐controlled sources and noise generators embedded in subcircuits. To illustrate the new approach, the properties and models of a number of components with electrical and non‐electrical characteristics are described. These models demonstrate how recent trends in open source simulation technology use embedded equations as integral elements in component and physical process models. Copyright © 2008 John Wiley & Sons, Ltd.
Liquid–liquid–liquid microextraction followed by HPLC with UV detection for quantitation of ephedrine in urine
Authors: Bagheri Habib , Khalilian Faezeh , Ahangar Laleh Enayati 
Published: September 2008

AbstractLiquid–liquid–liquid microextraction (LLLME) in combination with HPLC and UV detection has been used as a sensitive method for the determination of ephedrine in urine samples. Extraction process was performed in a homemade total glass vial without using a Teflon ring, usually employed. Ephedrine was first extracted from 3.5 mL of urine sample (pH 12) into a microfilm of toluene/benzene (50:50). The analyte was subsequently back extracted into an acidic microdrop solution (pH 2) suspended in the organic phase. The extract was then injected into the HPLC system directly. An enrichment factor of 137 along with a good sample clean‐up was obtained under the optimized conditions. The calibration curve showed linearity in the range of 0.01–50 mg/L with regression coefficient corresponding to 0.998. The LODs and LOQs, based on a S/N of 3 and 10, were 5 and 10 μg/L, respectively. The method was eventually applied for the determination of ephedrine in urine sample after oral administration of 5 mg single dose of drug.
Vitrification during the Isothermal Cure of Thermosets: Comparison of Theoretical Simulations with Temperature‐Modulated DSC and Dielectric Analysis
Authors: Fraga Iria , Montserrat Salvador , Hutchinson John M. 
Published: September 2008

AbstractVitrification during the isothermal cure of a thermoset, which is monitored by dynamic techniques such as temperature‐modulated differential scanning calorimetry (TMDSC) or dielectric analysis (DEA), is analyzed in terms of its dependence on frequency. A simulation was used to obtain the vitrification time as a function of frequency, considering it as the time when the (frequency‐dependent) glass transition temperature, Tg, of the curing system reaches the cure temperature. Simulations were carried out at different cure temperatures. Other parameters, such as the exponents (reaction orders) in the Kamal equation, λ in the DiBenedetto equation (controlling the dependence of Tg on the degree of cure), and the activation energy for the frequency dependence of Tg, were also considered. The results are compared with those obtained experimentally by a TMDSC technique at low frequencies and by DEA at high frequencies. From the simulations it is found that the vitrification time decreases nonlinearly with log(frequency) in the low frequency range but approaches a linear dependence at high frequencies, in agreement with experimental data.magnified image
Factor analysis reveals differences in brain metabolism in macaques with SIV/AIDS and those with SIV‐induced encephalitis
Authors: Lentz Margaret R. , Lee Vallent , Westmoreland Susan V. , Ratai Eva‐Maria , Halpern Elkan F. , González R. Gilberto 
Published: September 2008

AbstractMRS has often been used to study metabolic processes in the HIV‐infected brain. However, it remains unclear how changes in individual metabolites are related to one another in this context of virus‐induced central nervous system dysfunction. We used factor analysis (FA) to identify patterns of metabolite distributions from an MRS study of healthy macaques and those infected with simian immunodeficiency virus (SIV) which were moribund with AIDS. FA summarized the correlations from nine metabolites into three main factors. Factor 3 identified patterns that discern healthy animals from those with SIV/AIDS. Factor 2 was able to differentiate between animals that had encephalitis and those moribund with AIDS but lacking encephalitis. Specifically, Factor 2 was able to distinguish animals with moderate to severe encephalitis from animals with mild or no encephalitis as well as uninfected controls. FA not only confirmed the involvement of neuronal metabolites (N‐acetylaspartate and glutamate) in disease severity, but also detected changes in creatine and myo‐inositol that have not been observed in the SIV macaque model previously. These results suggest that the divergent pathways of N‐acetylaspartate and creatine in this disease may enable the commonly reported ratio N‐acetylaspartate/creatine to be a more sensitive marker of disease severity. Copyright © 2008 John Wiley & Sons, Ltd.
Properties of discrete Chebyshev collocation differential operators in curvilinear geometries
Authors: Pironkov P. , Schäfer M. , Krastev K. 
Published: September 2008

AbstractThe properties of discrete systems resulting from spectral Chebyshev collocation discretizations are investigated with respect to the solution efficiency of corresponding solvers. Complex geometries are encountered by a mapping technique to connect computational and physical domains. Several representative transformation techniques are considered. The influences of the differential operators, the boundary conditions, the geometry, and the number of grid points are systematically studied. The convergence properties of the BiCGSTAB method when iteratively solving the discrete systems are investigated. Copyright © 2008 John Wiley & Sons, Ltd.
On the weighted dyadic diaphony of digital (t, s)‐sequences
Authors: Kritzer Peter , Pillichshammer Friedrich 
Published: September 2008

AbstractIn this note, we present results on the weighted dyadic diaphony of digital (t, s)‐sequences over ℤ2. These results are closely linked to the worst‐case error for quasi‐Monte Carlo integration in certain spaces of functions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On freezing of a finite humid porous medium with a heat flux condition considering the factor for phase conversion
Authors: Marcus Eduardo A. Santillan 
Published: September 2008

AbstractThis work deals with a theoretical mathematical analysis of freezing (desublimation) of moisture in a finite porous medium with heat‐flux condition in x=0. The position of phase change front at time t, given by x =s (t), divides the porous body into two regions. In the first region there is no moisture movement, and in the other one the process of the coupled heat and moisture flows is described by the well known Luikov's system, considering that the factor for phase conversion is non zero. Equivalence between this problem and a system of Volterra integral equations is found. The existence of a unique local solution in time for this problem is also obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Symmetry and bifurcation in vestibular system
Authors: Golubitsky Marty , Shiau LieJune , Stewart Ian 
Published: September 2008

AbstractThe vestibular system in almost all vertebrates, humans included, controls balance by employing a set of six semicircular canals, three in each inner ear, to detect angular accelerations of the head. Signals from the canals are transmitted to neck motoneurons and activate eight corresponding muscle groups. These signals may be either excitatory or inhibitory, depending on the direction of acceleration. McCollum and Boyle have observed that in the cat the network of neurons concerned possesses octahedral symmetry, a structure deduced from the known innervation patterns (connections) from canals to muscles.We re‐derive the octahedral symmetry from mathematical features of the probable network architecture, and model the movement of the head in response to the activation patterns of the muscles concerned. We assume that connections among neck muscles can be modeled by a ‘coupled cell network’, a system of coupled ODEs whose variables correspond to the eight muscles, and that network also has octahedral symmetry. The network and its symmetries imply that these ODEs must be equivariant under a suitable action of the octahedral group.Using results of Ashwin and Podvigina, we show that with the appropriate group actions, there are six possible spatiotemporal patterns of time‐periodic states that can arise by Hopf bifurcation from an equilibrium corresponding to natural head motions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)