bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synaptophysin protein and mRNA expression in the human hippocampal formation from birth to old age
Authors: Eastwood Sharon L. , Weickert Cyndi Shannon , Webster Maree J. , Herman Mary M. , Kleinman Joel E. , Harrison Paul J. 
Published: June 2006

AbstractIn the human neocortex, progressive synaptogenesis in early postnatal life is followed by a decline in synaptic density, then stability from adolescence until middle age. No comparable data are available in the hippocampus. In this study, the integral synaptic vesicle protein synaptophysin, measured immunoautoradiographically, was used as an index of synaptic terminal abundance in the hippocampal formation of 37 subjects from 5 weeks to 86 yr old, divided into 4 age groups (10 infants, 15 adolescents/young adults, 6 adults, and 6 elderly). In all hippocampal subfields, synaptophysin was lowest in infancy, but did not differ significantly between the older age groups, except in dentate gyrus (DG) where the rise was delayed until adulthood. A similar developmental profile was found in the rat hippocampus. We also measured synaptophysin mRNA in the human subjects and found no age‐related changes, except in parahippocampal gyrus wherein the mRNA declined from infancy to adolescence, and again in old age. The synaptophysin protein data demonstrate a significant presynaptic component to human postnatal hippocampal development. In so far as synaptophysin abundance reflects synaptic density, the findings support an increase in hippocampal and parahippocampal synapse formation during early childhood, but provide no evidence for adolescent synaptic pruning. The mRNA data indicate that the maturational increases in synaptophysin protein are either translational rather than transcriptional in origin, or else are secondary to mRNA increases in neurons, the cell bodies of which lie outside the hippocampal formation. Published 2006 Wiley‐Liss, Inc.
A relook at NEH‐4 curve number data and antecedent moisture condition criteria
Authors: Mishra Surendra Kumar , Singh Vijay P. 
Published: June 2006

AbstractThis paper investigates the variation of the popular curve number (CN) values given in the National Engineering Hand Book–Section 4 (NEH‐4) of the Soil Conservation Service (SCS) with antecedent moisture condition (AMC) and soil type. Using the volumetric concept, involving soil, water, and air, a significant condensation of the NEH‐4 tables is achieved. This leads to a procedure for determination of CN for gauged as well as ungauged watersheds. The rainfall‐runoff events derived from daily data of four Indian watersheds exhibited a power relation between the potential maximum retention or CN and the 5‐day antecedent rainfall amount. Including this power relation, the SCS‐CN method was modified. This modification also eliminates the problem of sudden jumps from one AMC level to the other. The runoff values predicted using the modified method and the existing method utilizing the NEH‐4 AMC criteria yielded similar results. Copyright © 2006 John Wiley & Sons, Ltd.
Multiple modes of storm runoff generation in a North Carolina coastal plain watershed
Authors: Slattery Michael C. , Gares Paul A. , Phillips Jonathan D. 
Published: June 2006

AbstractThe results of field measurements conducted in a small (19·37 ha) agricultural watershed on the North Carolina coastal plain during the summer of 1996 are presented. The objective of the study was to develop a more complete understanding of basin response in the region with respect to stormflow generation and, in particular, to identify the processes that determine storm runoff and the conditions under which such processes occur. Twenty‐four storm events were monitored, including two tropical storm systems and two hurricanes. The data demonstrate considerable spatial and temporal heterogeneity in runoff generation within the watershed. Surface flowpaths, in the form of Hortonian overland flow and saturation overland flow, were found to be the dominant runoff processes during the storm events measured. The hillslope flowpaths had the same response time as the basin streamflow, but significantly shorter time of rise and lag times. The importance of Hortonian flow in a basin with sandy, permeable soils, as well as the rapid stormflow response in a low‐relief area with a humid climate, was contrary to expectations. This, coupled with the contingency of runoff response, suggests that it may be difficult to generalize about runoff generation mechanisms in broad terms, and that a synoptic approach may be more appropriate. Copyright © 2006 John Wiley & Sons, Ltd.
Complementary aspects of linear flood routing modelling and flood frequency analysis
Authors: Strupczewski Witold G. , Singh Vijay P. , Weglarczyk Stanislaw , Kochanek Krzysztof , Mitosek Henryk T. 
Published: June 2006

AbstractSimilarity and differences between linear flood routing modelling (LFRM) and flood frequency analysis (FFA) techniques are presented. The moment matching used in LFRM to approximate the impulse response function (IRF) was applied in FFA to derive the asymptotic bias caused by the false distribution assumption. Proceeding in this way, other estimation methods were used as approximation methods in FFA to derive the asymptotic bias. Using simulation experiments, the above investigation was extended to evaluate the sampling bias. As a feedback, the maximum likelihood method (MLM) can be used for approximating linear channel response (LCR) by the IRFs of conceptual models.Impulse responses of the convective diffusion and kinematic diffusion models were applied and developed as FFA models. Based on kinematic diffusion LFRM, the equivalence of estimation problems of discrete‐continuous distribution and single‐censored sample are shown both for the method of moments (MOM) and the MLM. Hence, the applicability of MOM is extended for the case of censored samples.Owing to the complexity and non‐linearity of hydrological systems and resulting processes, the use of simple models is often questionable. The rationale of simple models is discussed. The problems of model choice and overparameterization are common in mathematical modelling and FF modelling. Some results for the use of simple models in the stationary FFA are presented. The problems of model discrimination are then discussed.Finally, a conjunction of linear stochastic processes and LFRM is presented. The influence of river courses on stochastic properties of the runoff process is shown by combining Gaussian input with the LCR of the simplified Saint Venant model. It is shown that, from the classification of the ways of their development, both LFRM and FFA can benefit. Copyright © 2006 John Wiley & Sons, Ltd.
Artificial extracellular matrix proteins contain heparin‐binding and RGD‐containing domains to improve osteoblast‐like cell attachment and growth
Authors: Wu Suh‐Chin , Yu Jung‐Chuan , Hsu Shan‐hui , Chen David Chanhen 
Published: June 2006

AbstractThrough the recombinant DNA technology, it is possible to create artificial extracellular matrix (aECM) proteins with domains chosen to modulate cellular behaviors. In this study, we constructed three aECM proteins containing both heparin‐binding and RGD‐containing domains (387RGDS, Tri‐FN10, and TNC‐FN3) produced in Escherichia coli. Promotion of MG‐63 cell attachment and growth in two‐dimensional (2D) cultures (tissue culture plate, polycaprolactone membrane) and 3D cultures (Cytodex 1 and Plastic Plus microcarriers) were demonstrated on these three aECM protein‐coated surfaces. These three aECM proteins improved MG‐63 cell attachment and growth in the order TNC‐FN3 > Tri‐FN10 > 387RGDS in both 2D and 3D cultures. This study is the first report of the construction of aECM proteins that contain both heparin‐binding and RGD‐containing domains used in osteoblast tissue engineering applications. © 2006 Wiley Periodicals, Inc. Inc. J Biomed Mater Res, 2006
A DFT study on the relative affinity for oxygen of the α and β subunits of hemoglobin
Authors: Maréchal Jean‐Didier , Maseras Feliu , Lledós Agustí , Mouawad Liliane , Perahia David 
Published: June 2006

AbstractDFT calculations are carried out on computational models of the active center of the α and β subunits of hemoglobin in both its oxygenated (R) and deoxygenated (T) states. The computational models are defined by the full heme group, including all porphyrin substituents, and the four amino acids closer to it. The role of the protein environment is introduced by freezing the position of the α carbon atom of each of the four amino acids to the positions they have in the available PDB structures. Oxygen affinity is then evaluated by computing the energy difference between the optimized structures of the oxygenated and deoxygenated forms of each model. The results indicate a higher affinity of the α subunits over the β ones. Analysis of the computed structures points out to the strength of the hydrogen bond between the distal histidine and the oxygen molecule as a key factor in discriminating the different systems. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1446–1453, 2006
Metal–thiolate bonds in bioinorganic chemistry
Authors: Solomon Edward I. , Gorelsky Serge I. , Dey Abhishek 
Published: June 2006

AbstractMetal–thiolate active sites play major roles in bioinorganic chemistry. The MSthiolate bonds can be very covalent, and involve different orbital interactions. Spectroscopic features of these active sites (intense, low‐energy charge transfer transitions) reflect the high covalency of the MSthiolate bonds. The energy of the metal–thiolate bond is fairly insensitive to its ionic/covalent and π/σ nature as increasing MS covalency reduces the charge distribution, hence the ionic term, and these contributions can compensate. Thus, trends observed in stability constants (i.e., the Irving–Williams series) mostly reflect the dominantly ionic contribution to bonding of the innocent ligand being replaced by the thiolate. Due to high effective nuclear charges of the CuII and FeIII ions, the cupric– and ferric–thiolate bonds are very covalent, with the former having strong π and the latter having more σ character. For the blue copper site, the high π covalency couples the metal ion into the protein for rapid directional long range electron transfer. For rubredoxins, because the redox active molecular orbital is π in nature, electron transfer tends to be more localized in the vicinity of the active site. Although the energy of hydrogen bonding of the protein environment to the thiolate ligands tends to be fairly small, H‐bonding can significantly affect the covalency of the metal–thiolate bond and contribute to redox tuning by the protein environment. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1415–1428, 2006
Variation in Activation Energy of the Glass Transition for Polymers of Different Dynamic Fragility
Authors: Vyazovkin Sergey , Sbirrazzuoli Nicolas , Dranca Ion 
Published: June 2006

AbstractSummary: Variations of the effective activation energy E of glass transitions have been determined by applying an isoconversional method to DSC data on the glass transition in PVC, PBMA, PVP, and PEN. A variability parameter ΔE has been introduced to characterize the rate of decrease in E with increasing temperature. By using the present data and our previous results for PS, PET, and B2O3, it has been found that ΔE correlates with the values of dynamic fragility, increasing with the latter in approximately exponential fashion.Correlation of the variability parameter with the dynamic fragility.imageCorrelation of the variability parameter with the dynamic fragility.
Non‐Isothermal Crystallization of Hyperbranched Poly(ε‐caprolactone)s and Their Linear Counterpart
Authors: Choi Jeongsoo , Chun Sang‐Wook , Kwak Seung‐Yeop 
Published: June 2006

AbstractSummary: Three hyperbranched poly(ε‐caprolactone)s were prepared with the architectural variation in the length of linear backbone segments consisting of 5, 10, and 20 ε‐caprolactone units (accordingly given the names HPCL–5, –10, and –20, respectively) and in the number of branching points as characterized by 1H NMR end group analyses. The non‐isothermal crystallizations of HPCLs and LPCL were performed using DSC at various cooling rates and the kinetic study was further performed by using both Ozawa and Kissinger methods. All the kinetic parameters such as the cooling functions and the apparent activation energy of crystallization indicated that HPCLs with longer linear segments and fewer number of branching points showed faster crystallization rates, whereas LPCL exhibited an intermediate rate between HPCL–10 and HPCL–20, i.e., HPCL–5 < HPCL–10 < LPCL < HPCL–20. The decrease in the crystallization rate is attributed to the presence of heterogeneous branching points in HPCLs with shorter segments, which hinders the regular chain packing to crystallize. In addition, the faster crystallization of HPCL–20 compared to LPCL was associated with the higher cooperative chain mobility in the melt.Schematic illustrations for HPCL and LPCL.imageSchematic illustrations for HPCL and LPCL.
Synthesis of Silicone‐Methacrylate Copolymers by ATRP Using a Nickel‐Based Supported Catalyst
Authors: Duquesne Emmanuel , Habimana Jean , Degée Philippe , Dubois Philippe 
Published: June 2006

AbstractSummary: A nickel (II) bromide catalyst immobilized onto crosslinked diphenylphosphinopolystyrene (PS‐PPh3/NiBr2) was used for the synthesis of silicone‐methacrylate copolymers by atom transfer radical polymerization (ATRP) of various methacrylate monomers using ω‐bromide silicone chains as macroinitiator. The polymerization proved to be very well‐controlled when a sufficient amount of soluble ligand, i.e., triphenylphosphine (PPh3), was added to the polymerization medium. Under these conditions, this technique efficiently led to the production of different copolymers with controlled compositions and molecular weights as well as narrow polydispersity indices ($\overline M _{\rm w} /\overline M _{\rm n}$ < 1.5). The recovered copolymers proved to be almost free of catalyst residues. Indeed, inductively coupled plasma (ICP) analysis revealed a metal content lower than 100 ppm, representing only a few percent of the initial metal content in the polymerization medium.Synthesis of PDMS block copolymer in toluene catalyzed by PS‐PPh3/NiBr2 in the presence of soluble PPh3 at 90 °C.imageSynthesis of PDMS block copolymer in toluene catalyzed by PS‐PPh3/NiBr2 in the presence of soluble PPh3 at 90 °C.
Comparison of Polyamide‐6 Nanocomposites Based on Pristine and Organic Montmorillonite Obtained via Anionic Ring‐Opening Polymerization
Authors: Liu Andong , Xie Tingxiu , Yang Guisheng 
Published: June 2006

AbstractSummary: Exfoliated Na+‐MMT/polyamide‐6 and intercalated organic MMT/polyamide‐6 nanocomposites were prepared using sodium montmorillonite with water dispersion and organic MMT with acetone dispersion via anionic ring‐opening polymerization, respectively. The effects of Na+‐MMT and OMMT on the polyamide‐6 were compared. Analysis shows that incorporation of exfoliated Na+‐MMT obviously improved mechanical properties, thermal stability, crystalline rate and favored formation of a γ‐crystalline form of matrix, but intercalated OMMT has no obvious effect on it. Nanoscale dispersing Na+‐MMT dramatically elevated the viscosity of matrix comparing with pure polyamide‐6. FTIR analysis indicates that the exfoliated Na+‐MMT improved the stability of hydrogen bonding comparing with the OMMT treated by alkylammonium salt modifier, which is different from previous studies. It is believed that hydrogen bonding between Na+‐MMT and polyamide‐6 plays a pivotal role.FTIR spectra of the NH stretching region of (a) PA, (b) PAM and (c) PAO.imageFTIR spectra of the NH stretching region of (a) PA, (b) PAM and (c) PAO.
A Robust Proton NMR Method to Investigate Hard/Soft Ratios, Crystallinity, and Component Mobility in Polymers
Authors: Maus Andreas , Hertlein Christopher , Saalwächter Kay 
Published: June 2006

AbstractSummary: An improved proton NMR method for the real‐time measurement of the hard/soft ratio or the crystallinity, and the mobile‐fraction dynamics, in phase‐separated or semicrystalline polymers is presented. It avoids some difficulties associated with earlier approaches and can be applied on high‐ as well as inexpensive low‐field instrumentation. A pulsed mixed magic‐sandwich echo is shown to provide near‐quantitative refocusing of the rigid contribution to the initial part of the free induction decay. This essentially removes the need to account for signal loss during the receiver dead time, and the method should thus be useful for a variety of applications where the magnetization distribution over differently mobile fractions is to be determined. The overall decay of the mobile signal of a semicrystalline polymer was found to exhibit a significant field dependence, such that the apparent transverse relaxation function of the amorphous part is in a real‐time experiment best characterized by a subsequent Carr–Purcell–Meiboom–Gill pulse train. It is demonstrated to be mainly influenced by mobility, while instrumental effects play a minor role. The mobility of the amorphous fraction depends not only on the overall crystallinity, but also on the crystallization conditions, thus on the nanometer‐scale morphology.Isothermal crystallization of sPP monitored on a 20 MHz low‐field proton NMR spectrometer using the MSE‐CPMG experiment.imageIsothermal crystallization of sPP monitored on a 20 MHz low‐field proton NMR spectrometer using the MSE‐CPMG experiment.
Goal hierarchies as antecedents of market structure
Authors: Paulssen Marcel , Bagozzi Richard P. 
Published: June 2006

AbstractCurrent models of market structure are descriptive in nature and lack theoretical grounding in consumer behavior. Such grounding is especially needed in the specification of marketing strategies. A self‐regulatory model of consumer consideration‐set formation will be employed as a basis of market structure in this article. The authors propose and show that consumers regulate their behavior according to goals at different levels of their goal hierarchies, which in turn determine brand consideration. Differences in the salience of goals at different hierarchical levels lead to differences in the composition of consideration sets. It is precisely these individual differences in brand consideration that determine the structure of a market. The analysis of consumers' goal hierarchies therefore answers, in part, the question of why a market has a certain structure. Hypotheses on brand consideration and the role of system‐ and principle‐level goals are tested on a sample of 1,018 consumers of automobiles. © 2006 Wiley Periodicals, Inc.
Marketplace and personal space: Investigating the differential effects of attachment style across relationship contexts
Authors: Thomson Matthew , Johnson Allison R. 
Published: June 2006

AbstractAn individual's tendencies in purely personal relationships seem to lead to related tendencies in consumer relationships. The following article presents a study that illustrates how individual differences in personal relationship attachment style can be used to predict the likely success of consumer relationships. In addition, it illustrates how the success of consumption versus nonconsumption relationships can be explained by the effect of attachment style on the individual's perception of qualities of the relationship. © 2006 Wiley Periodicals, Inc.
A Novel Highly Resilient Nanocomposite Hydrogel with Low Hysteresis and Ultrahigh Elongation
Authors: Zhu Meifang , Liu Yang , Sun Bin , Zhang Wei , Liu Xiaoli , Yu Hao , Zhang Yu , Kuckling Dirk , Adler Hans‐Juergen P. 
Published: June 2006

AbstractSummary: A series of high clay content Laponite XLS/polyacrylamide (PAAm) nanocomposite hydrogels (S‐M gels) with excellent resilience, low elastic hysteresis, and ultrahigh elongation, have been successfully synthesized. Based on our results, it is concluded that the mechanical properties of nanocomposite hydrogels probably depend to a great extent on the hydrophilicity and flexibility of the macromolecules. Moreover, it is found that the transparency during the in‐situ polymerization of S‐M gels does not change, which is quite different from clay/poly(N‐isopropylacrylamide) nanocomposite hydrogels.Formation of nanocomposite hydrogels using Clay‐S by in‐situ polymerization.magnified imageFormation of nanocomposite hydrogels using Clay‐S by in‐situ polymerization.
Heat‐treated BMP‐2 depots release BMP‐2 in its bioactive form
Authors: Winkler L. , Müller R. , Wiemann M. 
Published: June 2006

AbstractSmall depots of locally fixed bone morphogenetic protein‐2 (BMP‐2), which were dried onto biocompatible carriers and afterwards heat‐treated, induce a local differentiation of contacting osteoblastic cells. Here we investigate whether such depots may act via a release of bioactive BMP‐2. For in vivo experiments we employed a modified gap‐healing approach using dump bell‐shaped implants made from titanium plasma‐sprayed Ti‐6Al‐4V, which were coated with BMP‐2 at only one side. Four weeks after implantation into the cancellous bone of the lateral femur condylus of adult sheep we observed a polar formation of new trabecular bone close to the side where BMP‐2 had been immobilized. We also tested whether BMP‐2 depots stimulate remote cells under cell culture conditions and found that alkaline phosphatase (ALP) of MC3T3‐E1 cells was induced over a distance of several millimetres. Experiments show that BMP‐2 at least in part desorbs from air‐dried and heat‐treated BMP‐2 depots in its bioactive form. Local depots of BMP‐2 may therefore allow to improve bone formation next to metal implants at predefined sites.
A Triphasic Theory for Growth in Biological Tissue – Basics and Applications
Authors: Ricken T. , Schwarz A. , Bluhm J. 
Published: June 2006

AbstractA triphasic model (solid, interstices filled with water containing nutrients) is proposed for the phenomenological description of transversely isotropic saturated biological tissues including the phenomena of growth. This is done within the framework of a macro‐mechanical description based on the Theory of Porous Media (TPM). Thereby, the constitutive equation of growth is determined by the state of stress and the local proportion of nutrients responsible for the mass exchange. The transversely isotropic behavior of the solid influences both the stress response and the internal fluid permeability, which is considered using an invariant formulation of the Helmholtz free energy and transversely isotropic permeability functions. After presenting the developed framework of the calculation concept including the representation of the governing weak formulations of the equations for large deformations, some representative numerical examples are examined.