bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capabilities of neurexins in the chick ciliary ganglion
Authors: Ross Brendon S. , Conroy William G. 
Published: December 2007

AbstractTranscellular interactions between neuroligins (NL) and β‐neurexin have been widely documented to promote maturation and function of both glutamatergic and GABAergic synapses. Recently it has been shown that neuroligin‐1 plays a similar role at nicotinic synapses on chick ciliary ganglion neurons in culture, acting from the postsynaptic side to enhance transmitter release from adjacent cholinergic terminals and boost nicotinic input to the cells. We show here that the ciliary ganglion expresses three forms of neuroligin as well as two β‐neurexins and an α‐neurexin. Overexpression of the β‐neurexins, but not the α‐neurexin, can induce clustering of endogenous PSD‐95 in adjacent neurons, presumably engaging neuroligin in the postsynaptic cell. The trans effects of β‐neurexins are selective; though both α3‐ and α7‐containing nicotinic receptors are available on opposing cells, β‐neurexins induce coclustering of α3‐ but not α7‐containing nicotinic receptors. Overexpression of other putative synaptogenic molecules, including SynCAM and L1, are ineffective at trans‐clustering of PSD‐95 on adjacent neurons. The β‐neurexins also exert a cis effect, coclustering presynaptic markers along with β‐neurexin in neurites juxtaposed to postsynaptic proteins, consistent with organizing presynaptic components as well. Striated muscle, the synaptic target of ciliary neurons in vivo, also expresses neuroligin. The results demonstrate that NL and neurexins are present at multiple sites in nicotinic cholinergic pathways and suggest the possibility of both cis‐ and trans‐interactions to influence nicotinic signaling. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Developmental expression patterns of the zebrafish small heat shock proteins
Authors: Marvin Martha , O'Rourke Devon , Kurihara Tomoki , Juliano Courtney E. , Harrison Krista L. , Hutson Lara D. 
Published: December 2007

AbstractSmall heat shock proteins (sHSPs), or α‐crystallins, are low‐molecular weight proteins found in every kingdom and nearly every species examined to date. Many, if not all, sHSPs act as molecular chaperones. Several also have functions independent of their chaperone activity, and at least a few are expressed in specific spatiotemporal patterns during embryonic and/or juvenile stages, suggesting specific roles during development. To date, however, no one has systematically characterized the expression patterns of all of the sHSPs during development in any organism. We have characterized the normal heat shock‐induced expression patterns of all 13 zebrafish sHSPs during development. Seven of the sHSPs are expressed in a tissue‐specific manner during development, and five are upregulated by heat shock. The results of these studies provide a foundation for analysis of sHSP function during normal development and their roles in protecting cells from the effects environmental stressors. Developmental Dynamics 237:454–463, 2008. © 2007 Wiley‐Liss, Inc.
Characterization of the cardiac phenotype in neonatal Ts65Dn mice
Authors: Williams Austin D. , Mjaatvedt Corey H. , Moore Clara S. 
Published: December 2007

AbstractThe Ts65Dn mouse is the most‐studied of murine models for Down syndrome. Homology between the triplicated murine genes and those on human chromosome 21 correlates with shared anomalies of Ts65Dn mice and Down syndrome patients, including congenital heart defects. Lethality is associated with inheritance of the T65Dn chromosome, and anomalies such as right aortic arch with Kommerell's diverticulum and interrupted aortic arch were found in trisomic neonates. The incidence of gross vascular abnormalities was 17% in the trisomic population. Histological analyses revealed interventricular septal defects and broad foramen ovale, while immunohistochemistry showed abnormal muscle composition in the cardiac valves of trisomic neonates. These findings confirm that the gene imbalance present in Ts65Dn disrupts crucial pathways during cardiac development. The candidate genes for congenital heart defects that are among the 104 triplicated genes in Ts65Dn mice are, therefore, implicated in the dysregulation of normal cardiogenic pathways in this model. Developmental Dynamics 237:426–435, 2008. © 2007 Wiley‐Liss, Inc.
Comparison of molecular and cellular events during lower jaw regeneration of newt (Cynops pyrrhogaster) and West African clawed frog (Xenopus tropicalis)
Authors: Kurosaka Hiroshi , Takano‐Yamamoto Teruko , Yamashiro Takashi , Agata Kiyokazu 
Published: December 2007

AbstractWhen mammals, including humans, lose a major part of their lower jaw, they are unable to regenerate the lost structures. Urodele amphibians, especially newts, can regenerate their lower jaw after amputation, whereas most anuran amphibians, including the West African clawed frog, can not. In the present study, we investigated the difference between newts and frogs during lower jaw regeneration. One difference was the distribution of myosin heavy chain (MHC) mRNA after lower jaw amputation: MHC mRNA was immediately expressed at the tip of the amputated lower jaw in newts but not in frogs. Moreover, there were proliferating cells that expressed Pax7 in newts but not in frogs, although proliferating cells were present in both animals. These results suggest that the difference of the jaw‐regenerating abilities between newts and frogs depends on the expression of MHC mRNA at the tip of the amputated jaw and the contribution of Pax7‐positive cells. Developmental Dynamics 237:354–365, 2008. © 2007 Wiley‐Liss, Inc.
Sensitive chiral analysis by CE: An update
Authors: Sánchez‐Hernández Laura , Crego Antonio Luis , Marina María Luisa , García‐Ruiz Carmen 
Published: December 2007

AbstractA general view of the different strategies used in the last years to enhance the detection sensitivity in chiral analysis by CE is provided in this article. With this purpose and in order to update the previous review by García‐Ruiz et al., the articles appeared on this subject from January 2005 to March 2007 are considered. Three were the main strategies employed to increase the detection sensitivity in chiral analysis by CE: (i) the use of off‐line sample treatment techniques, (ii) the employment of in‐capillary preconcentration techniques based on electrophoretic principles, and (iii) the use of alternative detection systems to the widely employed on‐column UV–Vis absorption detection. Combinations of two or three of the above‐mentioned strategies gave rise to adequate concentration detection limits up to 10−10 M enabling enantiomer analysis in a variety of real samples including complex biological matrices.
Rapid‐on‐chip determination of dielectric properties of biological cells using imaging techniques in a dielectrophoresis dot microsystem
Authors: Fatoyinbo Henry O. , Hoettges Kai F. , Hughes Michael P. 
Published: December 2007

AbstractDielectrophoresis is a technique whereby polarisable particles are manipulated by non‐uniform alternating electric fields. A specific application of this technique is deducing the dielectric properties of cells from analysis of the dielectrophoretic spectrum of that particular cell population. We have developed a new microelectrode geometry consisting of two parallel electrode planes, one of which is patterned with arrays of circular apertures or ‘dots’. The radial symmetry of the dots means that the polarisability of the particles within the dot can be directly related to change shifts in light transmission through the dot, and quantified from analysis of digital images. We have validated our system using well‐characterised cell types and found a high degree of agreement to published data. Furthermore, we have observed that at high particle concentrations, electrostatic inter‐particle repulsion causes spontaneous, rapid particle re‐dispersion over the dot volume upon removal of an applied electric field. This allows the automated acquisition of a spectrum of 26 data points in approximately 15 min.
Boussinesq cut‐cell model for non‐linear wave interaction with coastal structures
Authors: Ning D. Z. , Zang J. , Liang Q. , Taylor P. H. , Borthwick A. G. L. 
Published: December 2007

AbstractBoussinesq models describe the phase‐resolved hydrodynamics of unbroken waves and wave‐induced currents in shallow coastal waters. Many enhanced versions of the Boussinesq equations are available in the literature, aiming to improve the representation of linear dispersion and non‐linearity. This paper describes the numerical solution of the extended Boussinesq equations derived by Madsen and Sørensen (Coastal Eng. 1992; 15:371–388) on Cartesian cut‐cell grids, the aim being to model non‐linear wave interaction with coastal structures. An explicit second‐order MUSCL‐Hancock Godunov‐type finite volume scheme is used to solve the non‐linear and weakly dispersive Boussinesq‐type equations. Interface fluxes are evaluated using an HLLC approximate Riemann solver. A ghost‐cell immersed boundary method is used to update flow information in the smallest cut cells and overcome the time step restriction that would otherwise apply. The model is validated for solitary wave reflection from a vertical wall, diffraction of a solitary wave by a truncated barrier, and solitary wave scattering and diffraction from a vertical circular cylinder. In all cases, the model gives satisfactory predictions in comparison with the published analytical solutions and experimental measurements. Copyright © 2007 John Wiley & Sons, Ltd.
Data assimilation: Mathematical and statistical perspectives
Authors: Apte A. , Jones C. K. R. T. , Stuart A. M. , Voss J. 
Published: December 2007

AbstractThe bulk of this paper contains a concise mathematical overview of the subject of data assimilation, highlighting three primary ideas: (i) the standard optimization approaches of 3DVAR, 4DVAR and weak constraint 4DVAR are described and their interrelations explained; (ii) statistical analogues of these approaches are then introduced, leading to filtering (generalizing 3DVAR) and a form of smoothing (generalizing 4DVAR and weak constraint 4DVAR) and the optimization methods are shown to be maximum a posteriori estimators for the probability distributions implied by these statistical approaches; and (iii) by taking a general dynamical systems perspective on the subject it is shown that the incorporation of Lagrangian data can be handled by a straightforward extension of the preceding concepts.We argue that the smoothing approach to data assimilation, based on statistical analogues of 4DVAR and weak constraint 4DVAR, provides the optimal solution to the assimilation of space–time distributed data into a model. The optimal solution obtained is a probability distribution on the relevant class of functions (initial conditions or time‐dependent solutions). The approach is a useful one in the first instance because it clarifies the notion of what is the optimal solution, thereby providing a benchmark against which existing approaches can be evaluated. In the longer term it also provides the potential for new methods to create ensembles of solutions to the model, incorporating the available data in an optimal fashion.Two examples are given illustrating this approach to data assimilation, both in the context of Lagrangian data, one based on statistical 4DVAR and the other on weak constraint statistical 4DVAR. The former is compared with the ensemble Kalman filter, which is thereby shown to be inaccurate in a variety of scenarios. Copyright © 2007 John Wiley & Sons, Ltd.
Der lange Weg zum sichtbaren Atom
Authors: Urban Knut 
Published: December 2007

AbstractSeit Jahrhunderten kämpfen Physiker und Ingenieure gegen Abbildungsfehler von Mikroskopen. Mit hochauflösenden Durchstrahlungs‐Elektronenmikroskopen haben sie die Schwächen weiter minimiert – und bringen so Forschung und Technik voran
Membrane permeability properties of dental adhesive films
Authors: Carrilho Marcela R. , Tay Franklin R. , Donnelly Adam M. , Agee Kelli A. , Carvalho Ricardo M. , Hosaka Keiichi , Reis Alessandra , Loguercio Alessandro D. , Pashley David H. 
Published: December 2007

AbstractThis study evaluated the permeability properties of five experimental resin membranes that ranged from relatively hydrophobic to relatively hydrophilic to seal acid‐etched dentin saturated with water or ethanol. The experimental resins (R1, R2, R3, R4, and R5) were evaluated as neat bonding agents or as solutions solvated with ethanol (70% resin/30% ethanol). The quality of dentin sealing by these experimental resins was expressed in terms of reflection coefficients calculated as the ratio of the effective osmotic pressure to the theoretical osmotic pressure of test solutions. The effective osmotic pressure produced across resin‐bonded dentin was induced in hypertonic solutions (CaCl2 or albumin) at zero hydrostatic pressure. The outward fluid flow induced by these solutions was brought to zero by applying an opposing negative hydrostatic pressure. The least hydrophilic resins blends, R1 and R2, exhibited significantly (p < 0.05) higher reflection coefficients than the most hydrophilic resins (R4 and R5) in both conditions of dentin saturation (water and ethanol). The reflection coefficients of neat resins were, in general, significantly higher when compared with their corresponding solvated versions in both conditions of dentin saturation. In dentin saturated with ethanol, bonding with neat or solvated resins, resulted in reflection coefficients that were significantly higher when compared with the results obtained in dentin saturated with water. Reflection coefficients of CaCl2 (ca. 1 × 10−4) were significantly lower (p < 0.05) than for albumin (ca. 3 × 10−2). Application of hydrophobic resins may provide better sealing of acid‐etched dentin if the substrate is saturated with ethanol, instead of water. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
In vitro degradation and in vivo biocompatibility study of a new linear poly(urethane urea)
Authors: Asplund Basse , Aulin Cecilia , Bowden Tim , Eriksson Niklas , Mathisen Torbjörn , Bjursten Lars‐Magnus , Hilborn Jöns 
Published: December 2007

AbstractSegmented poly(urethane urea)s (PUUs) with hard segments derived only from methyl 2,6‐diisocyantohexanoate (LDI) without the use of a chain extender have previously been described. These materials, which contain hard segments with multiple urea linkages, show exceptionally high strain capability (1600–4700%). In the study reported here, the rate and effect of hydrolysis of these materials were determined for gamma‐sterilized and nonsterilized samples. Materials investigated contained PCL, PTMC, P(TMC‐co‐CL), P(CL‐co‐DLLA), or P(TMC‐co‐DLLA) as soft segments and, as well as their mechanical properties, changes in mass, inherent viscosity (I.V.), and thermal properties were studied over 20 weeks. Results showed that the degradation rate was dependant on the soft segment structure, with a higher rate of degradation for the polyester‐dominating PUUs exhibiting a substantial loss in I.V. A tendency of reduction of tensile strength and strain hardening was seen for all samples. Also, loss in elongation at break was detected, for PUU‐P(CL‐DLLA) it went from 1600% to 830% in 10 weeks. Gamma radiation caused an initial loss in I.V. and induced more rapid hydrolysis compared with nonsterilized samples, except for PUU‐PTMC. A cytotoxicity test using human fibroblasts demonstrated that the material supports cell viability. In addition, an in vivo biocompatibility study showed a typical foreign body reaction after 1 and 6 weeks. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Y‐TZP zirconia run against highly crosslinked UHMWPE tibial inserts: Knee simulator wear and phase‐transformation studies
Authors: Tsukamoto Riichiro , Williams Paul A. , Clarke Ian C. , Pezzotti Giuseppe , Shoji Hiromu , Akagi Masao , Yamamoto Kengo 
Published: December 2007

AbstractBackground:Zirconia (ZrO2) ceramics combined with highly cross‐linked polyethylene appears to be a promising approach to minimize wear in artificial knee joints. The wear performance of yttria‐stabilized zirconia (YZr) femoral condyles on 7‐Mrad tibial inserts was compared in a knee simulator to CoCr bearing on 3.5‐Mrad inserts.Methods:The knee design was the Bi‐Surface™ type with a 9‐year clinical history in Japan (JMM, Japan). A displacement‐controlled knee simulator was used with kinematics that included 20° flexion, ±5° rotation, and 6 mm anterior/posterior translation. Lubricant was alpha‐calf serum, test duration was 10 million cycles (10 Mc), and wear was measured by weight‐loss techniques. The wear zones were studied by laser interferometry, scanning electron microscopy, and Raman microprobe spectroscopy.Results:At 10 Mc the wear rates of the CoCr controls averaged 4.5 mm3/Mc. This was within 7% of the prior estimate at 5‐Mc duration and comparable to Bi‐Surface wear data from another laboratory. The CoCr condyles increased in roughness (Ra) from <50 nm to average Ra = 250 nm due to linear scratching. The ceramic condyles remained pristine throughout the wear study (Ra <7nm). With the YZr/7‐Mrad combination, the weight change had a positive slope over at 10 Mc, which meant that the actual polyethylene wear was unmeasurable. Microscopic examinations at 10 Mc showed that the zirconia surfaces were intact and there was no detectable change from tetragonal to monoclinic phase.Interpretation:Our laboratory knee wear simulation appeared very supportive of the 9‐year YZr/PE clinical results with Bi‐Surface total knee replacements in Japan. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
In vitro μTBS of one‐bottle adhesive systems: Sound versus artificially‐created caries‐affected dentin
Authors: Erhardt Maria Carolina G. , Rodrigues José Augusto , Valentino Thiago Assunção , Ritter André Vicente , Pimenta Luiz André Freire 
Published: December 2007

AbstractThis in vitro study aimed to evaluate a pH‐cycling model for simulation of caries‐affected dentin (CAD) surfaces, by comparing the bond strength of etch‐and‐rinse adhesive systems on sound and artificially‐created CAD. Dentin substrates with different mineral contents and morphological patterns were created by submitting buccal bovine dentin to the following treatments: (1) immersion in artificial saliva during the experimental period (sound dentin, SD), or (2) induction to a CAD condition by means of a dynamic pH‐cycling model (8 cycles, demineralization for 3 h followed by mineralization for 45 h). The bond strength of Excite or Prime and Bond NT adhesive systems was assessed using the microtensile bond strength (μTBS) test. Dentin microhardness was determined by cross‐sectional Knoop evaluations. Resin–dentin morphology after the treatments was examined by scanning electron microscopy. SD produced significantly higher μTBS than CAD for both adhesives evaluated, without differences between materials. CAD exhibited lower microhardness than SD. Morphological analysis showed marked distinctions between SD and CAD bonded interfaces. Under the conditions of this study, differences in morphological pattern and dentin mineral content may help to explain resin–dentin bond strengths. The proposed pH‐cycling model may be a suitable method to simulate CAD surfaces for bonding evaluations. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
The influence of the acidic component of the gas‐foaming porogen used in preparing an injectable porous calcium phosphate cement on its properties: Acetic acid versus citric acid
Authors: Hesaraki Saeed , Zamanian Ali , Moztarzadeh Fatollah 
Published: December 2007

AbstractIn the present study, macroporous calcium phosphate cements (CPCs) were prepared using a porogen; that is, the gas‐foaming technique. The objective was to investigate the influence of the acidic component of the porogen (acetic acid versus citric acid) on several properties of a specified CPC. In all of the cements prepared, the basic component of the porogen was the same, namely, NaHCO3, and it was added to the powder phase of the cement, while the acidic component of the porogen was dissolved in the liquid phase of the cement. The cements were characterized in terms of initial setting time, porosity, crystallinity, injectability and compressive strength. Also, XRD, FTIR, and SEM techniques were employed to evaluate the phase composition, the chemical groups and the morphological aspects of the porous cements during setting. It was found that the presence of a porogen in a CPC led to significant decreases in both its initial setting time and compressive strength. A CPC made using acetic acid contained a larger amount of the apatite phase but was significantly less injectable and less porous than when citric acid was used. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Effect of cyclic loading on bonding of fiber posts to root canal dentin
Authors: Albaladejo Alberto , Osorio Raquel , Aguilera Fatima S. , Toledano Manuel 
Published: December 2007

AbstractThis study evaluated the effect of mechanical loading on microtensile bond strength (MTBS) when luting fiber posts to root canal dentin. Forty maxillary premolars were endodontically treated, and the roots were prepared for post cementation using the FRC Postec system. A light‐cured composite (Clearfil Photo Core, Kuraray) was used in combination with four adhesive systems: Single Bond (3M ESPE), Multilink Primer (Vivadent), Clearfil Photo Bond (Kuraray), and Clearfil New Bond (Kuraray). A composite build‐up was performed around the root to provide adequate gripping during testing. For each experimental group, half of the specimens were load cycled under 90 N (5000 cycles, 3 cycles/s). Specimens were cut to obtain beams with the post in the center and with the radicular dentin overlaid by the composite build‐up on each side. Microtensile testing was performed with a universal testing machine at a cross‐head speed of 0.5 mm/min. The failure mode was classified under a stereomicroscope. ANOVA and Student–Newman–Keuls multiple comparison tests were performed. After 24 h, all adhesives performed similarly. When specimens were subjected to mechanical loading, decreases in MTBS were observed for Clearfil New Bond and Multilink Primer. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008