bluuebunny/crossref_metadata_2025 huggingface dataset:
Capabilities of neurexins in the chick ciliary ganglion
Authors: Ross Brendon S. , Conroy William G.
Published: December 2007

Transcellular 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

Small 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

The 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

When 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

A 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

Dielectrophoresis 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

Boussinesq 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

The 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

Seit 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
Magnetic resonance imaging of hepatic fibrosis: Emerging clinical applications
Authors: Talwalkar Jayant A. , Yin Meng , Fidler Jeff L. , Sanderson Schuyler O. , Kamath Patrick S. , Ehman Richard L.
Published: December 2007

Chronic liver disease and cirrhosis remains a major public health problem worldwide. While the majority of complications from chronic liver disease result from progressive hepatic fibrosis, the available diagnostic tests used in clinical practice are not sensitive or specific enough to detect occult liver injury at early or intermediate stages. While liver biopsy can stage the extent of fibrosis at diagnosis, its utility as a tool for longitudinal monitoring will be limited at the population level. To date, a number of methods including serum marker panels and ultrasound-based transient elastrography have been proposed for the non-invasive identification of hepatic fibrosis. Novel techniques including magnetic resonance (MR) spectroscopy, diffusion weighted MR, and MR elastography have also emerged for detecting fibrosis. In contrast to other non-invasive methods, MR imaging holds the promise of providing functional and biological information about hepatic pathophysiology as it relates to the natural history and future treatment of hepatic fibrosis. (Hepatology 2007.)
Inhibition of adiponectin production by homocysteine: A potential mechanism for alcoholic liver disease
Authors: Song Zhenyuan , Zhou Zhanxiang , Deaciuc Ion , Chen Theresa , McClain Craig J.
Published: December 2007

Although recent evidence suggests that down-regulation of production of the adipocyte hormone adiponectin has pathophysiological consequences for the development of alcoholic liver disease (ALD), the underlying mechanisms are elusive. Abnormal hepatic methionine-homocysteine metabolism induced by prolonged alcohol exposure has been reported both in clinical and experimental studies of ALD. Here, we conducted both in vivo and in vitro experiments to examine the effects of prolonged alcohol exposure on homocysteine levels in adipose tissue, its potential involvement in regulating adiponectin production, and the consequences for ALD. Chronic alcohol exposure decreased the circulating adiponectin concentration and adiponectin messenger RNA (mRNA) and protein levels in epididymal fat pads. Alcohol feeding induced modest hyperhomocysteinemia and increased homocysteine levels in the epididymal fat pad, which was associated with decreased mRNA levels of cystationine β-synthase. Betaine supplementation (1.5%, wt/vol) in the alcohol-fed mice reduced homocysteine accumulation in adipose tissue and improved adiponectin levels. Moreover, exogenous homocysteine administration reduced gene expression, protein levels, and secretion of adiponectin in primary adipocytes. Furthermore, rats fed a high-methionine diet (2%, wt/wt) were hyperhomocysteinemic and had decreased adiponectin levels in both plasma and adipose tissue, which was associated with suppressed AMP-activated protein kinase activation in the liver. Mechanistic studies revealed that both inactivation of the extracellular signal regulated kinase 1/2 pathway and induction of endoplasmic reticulum stress response, specifically C/EBP homologous protein expression, may contribute to the inhibitory effect exerted by homocysteine.

Conclusion:

Chronic alcohol feeding caused abnormal accumulation of homocysteine in adipocytes, which contributes to decreased adiponectin production in ALD.
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

This 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

Segmented 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

Background:

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

This 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

In 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

This 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
Clinical evaluations of OSTEON® as a new alloplastic material in sinus bone grafting and its effect on bone healing
Authors: Kim Young‐Kyun , Yun Pil‐Young , Lim Sung‐Chul , Kim Su‐Gwan , Lee Hyo‐Jung , Ong Joo L.
Published: December 2007

Purpose:

The objective of this study was to clinically evaluate the use of OSTEON® as a sinus graft material and to measure the effect of healing at 4 and 6 months after surgery.

Materials and Methods:

After sinus graft using OSTEON® in 17 patients, bone specimens were collected from lateral sinus using 2.0‐mm trephine bur at the time of 4 or 6 months after surgery. Histology of the bone specimens was prepared and the percentage of newly formed bone fraction, lamellar bone/woven bone ratio (LB/WB), and newly formed bone/graft material ratio (NB/GM) were measured to indicate the suitability of the materials and the successful healing of the graft.

Results:

The morphology of OSTEON® was observed to be interconnected, with 77% porosity and a pore size of 300–500 μm. After implantation, the mean percentage of newly formed bone fraction after 4 months and 6 months surgery was 40.6 and 51.9%, respectively. Statistical analysis indicated no significant difference (p = 0.135) in the newly formed bone fraction between the two postoperative periods. The mean LB/WB ratio after 4 months and 6 months surgery was 0.14 and 0.45, respectively, with significant difference observed between the two postoperative periods (p = 0.027). Additionally, the mean NB/GM ratio after 4 months and 6 months surgery was 1.95 and 7.72, respectively, with significant difference observed between the two postoperative periods (p = 0.046).

Conclusion:

It was concluded that OSTEON® is suitable for use in sinus graft application since desirable time‐dependent healing was demonstrated. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Changes in stiffness of demineralized dentin following application of collagen crosslinkers
Authors: Bedran‐Russo Ana Karina B. , Pashley David H. , Agee Kelli , Drummond James L. , Miescke Klaus J.
Published: December 2007

It is thought that increasing the strength of the dentin matrix using crosslinking agents may improve both the strength and the durability of resin–dentin bonds. The purpose of this study was to evaluate the effect of two collagen crosslinking agents (glutaraldehyde, GD and grape seed extract, GSE) on the modulus of elasticity of demineralized dentin. Sound molar fragments were fully demineralized and divided into five groups according to the type and concentration of crosslinking agents: 2.5% GD; 5% GD, 25% GD; 0.65% GSE; 6.5% GSE. Specimens were immersed in their respective solution and tested at baseline, 10 min, 30 min, 1 h, 2 h, 4 h. The elastic modulus of dentin was significantly affected by the treatment (p < 0.01) and exposure time (p < 0.01). There was a statistically significant interaction between the two factors evaluated (treatment vs. time p < 0.01). Mean baselines values varied between 4.8 and 6.2 MPa in water; after 4 h of treatment the values increased between 34.9 and 242.5 MPa, that were treatment time and agent dependent. The use of these collagen crosslinkers to increase the stiffness of demineralized dentin, was both concentration and time dependent. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Solvent/non‐solvent sintering: A novel route to create porous microsphere scaffolds for tissue regeneration
Authors: Brown Justin L. , Nair Lakshmi S. , Laurencin Cato T.
Published: December 2007

Solvent/non‐solvent sintering creates porous polymeric microsphere scaffolds suitable for tissue engineering purposes with control over the resulting porosity, average pore diameter, and mechanical properties. Five different biodegradable biocompatible polyphosphazenes exhibiting glass transition temperatures from −8 to 41°C and poly (lactide‐co‐glycolide), (PLAGA) a degradable polymer used in a number of biomedical settings, were examined to study the versatility of the process and benchmark the process to heat sintering. Parameters such as: solvent/non‐solvent sintering solution composition and submersion time effect the sintering process. PLAGA microsphere scaffolds fabricated with solvent/non‐solvent sintering exhibited an interconnected porosity and pore size of 31.9% and 179.1 μm, respectively which was analogous to that of conventional heat sintered PLAGA microsphere scaffolds. Biodegradable polyphosphazene microsphere scaffolds exhibited a maximum interconnected porosity of 37.6% and a maximum compressive modulus of 94.3 MPa. Solvent/non‐solvent sintering is an effective strategy for sintering polymeric microspheres, with a broad spectrum of glass transition temperatures, under ambient conditions making it an excellent fabrication route for developing tissue engineering scaffolds and drug delivery vehicles. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Theoretical study on the hydrolysis mechanism of N,N‐dimethyl‐N′‐(2‐oxo‐1, 2‐dihydro‐pyrimidinyl)formamidine: Water‐assisted mechanism and cluster‐continuum model
Authors: Wu Yong , Jin Lu , Xue Ying , Xie Dai Qian , Kim Chan Kyung , Guo Yong , Yan Guo Sen
Published: December 2007

The hydrolysis reaction of N,N‐dimethyl‐N′‐(2‐oxo‐1, 2‐dihydro‐pyrimidinyl)formamidine (DMPFA), a model compound of the antivirus drug amidine‐3TC (3TC = 2′, 3′‐dideoxy‐3′‐thiacytidine), is investigated by the hybrid density functional theory B3LYP/6‐31+G (d,p) method. The hydrolysis reaction of the title compound is predicted to undergo via two pathways, each of which is a stepwise process. Path A is the addition of H2O to the CN double bond in the amidine group to form a tetrahedral structure in its first step, and then the transfer of the H atom of hydroxyl leads to the corresponding products via four possible channels. Path B simultaneously involves the nucleophilic attack of H2O to the C atom of the CN bond and the proton transfer to the N atom of amino group leading to the cleavage of the CN single bond in the amidine group. The results indicate that path A is more favorable than path B in the gas phase. Moreover, to simulate the title reaction in aqueous solution, water‐assisted mechanism and the cluster‐continuum model, based on the SCRF/CPCM model, are taken into account in our work. The results indicate that it is rational for two water molecules served as a bridge to assist in the first step of path A and that cytosine rather than the cytosine‐substituted formamide should be released from the tetrahedral intermediate via s six‐membered cycle transition state (channel 2). Our calculations exhibit that the process toward the tetrahedral intermediate is the rate‐determining step both in the gas phase and in aqueous solution. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Dynamic structures of phosphodiesterase‐5 active site by combined molecular dynamics simulations and hybrid quantum mechanical/molecular mechanical calculations
Authors: Xiong Ying , Lu Hai‐Ting , Zhan Chang‐Guo
Published: December 2007

Various quantum mechanical/molecular mechanical (QM/MM) geometry optimizations starting from an x‐ray crystal structure and from the snapshot structures of constrained molecular dynamics (MD) simulations have been performed to characterize two dynamically stable active site structures of phosphodiesterase‐5 (PDE5) in solution. The only difference between the two PDE5 structures exists in the catalytic, second bridging ligand (BL2) which is HO− or H2O. It has been shown that, whereas BL2 (i.e. HO−) in the PDE5(BL2 = HO−) structure can really bridge the two positively charged metal ions (Zn2+ and Mg2+), BL2 (i.e. H2O) in the PDE5(BL2 = H2O) structure can only coordinate Mg2+. It has been demonstrated that the results of the QM/MM geometry optimizations are remarkably affected by the solvent water molecules, the dynamics of the protein environment, and the electronic embedding charges of the MM region in the QM part of the QMM/MM calculation. The PDE5(BL2 = H2O) geometries optimized by using the QM/MM method in different ways show strong couplings between these important factors. It is interesting to note that the PDE5(BL2 = HO‐) and PDE5(BL2 = H2O) geometries determined by the QM/MM calculations neglecting these three factors are all consistent with the corresponding geometries determined by the QM/MM calculations that account for all of these three factors. These results suggest the overall effects of these three important factors on the optimized geometries can roughly cancel out. However, the QM/MM calculations that only account for some of these factors could lead to considerably different geometries. These results might be useful also in guiding future QM/MM geometry optimizations on other enzymes. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Protein loaded mesoporous silica spheres as a controlled delivery platform
Authors: Ho Jenny , Danquah Michael K , Wang Huanting , Forde Gareth M
Published: December 2007

BACKGROUND: The adsorption of bovine serum albumin (BSA) onto mesoporous silica spheres (MPS) synthesized from silica colloids was studied employing real time in situ measurements. The stabilities of the BSA at different pH values, their isoelectric points and zeta potentials were determined in order to probe the interactions between the protein and the mesoporous silica.

RESULTS: The pore size of MPS was designed for protein, and this, coupled with an in depth understanding of the physico‐chemical characteristics of the protein and MPS has yielded a better binding capacity and delivery profile. The adsorption isotherm at pH 4.2 fitted the Langmuir model and displayed the highest adsorption capacity (71.43 mg mL−1 MPS). Furthermore, the delivery rates of BSA from the MPS under physiological conditions were shown to be dependent on the ionic strength of the buffer and protein loading concentration.

CONCLUSION: Economics and scale‐up considerations of mesoporous material synthesized via destabilization of colloids by electrolyte indicate the scaleability and commercial viability of this technology as a delivery platform for biopharmaceutical applications. Copyright © 2007 Society of Chemical Industry
Phylogenetic relationships of South American Alligatorids and the Caiman of Madeira River
Authors: Hrbek Tomas , Vasconcelos William Rangel , Rebelo George , Farias Izeni Pires
Published: December 2007

We analyzed DNA sequences of the mitochondrial cytochrome b gene (cyt b), the nuclear Recombination Activating Gene 1 (RAG1) and the myelocytomatosis oncogene (MYC) to infer the phylogenetic relationship of Caiman crocodilus and Caiman yacare, and other South American alligatorid crocodilian species. Phylogenetic relationships were robustly supported with Paleosuchus sister to Melanosuchus and Caiman. Phylogenetic relationships of C. crocodilus and C. yacare were unclear as these two species share mitochondrial and nuclear haplotypes. Specifically this sharing occurs among specimens of C. yacare and C. crocodilus from the Madeira River drainage. Two potential explanations stand out: secondary contact followed by hybridization, and differentiation along a cline. Current data cannot resolve between these two competing hypotheses. In comparison with C. yacare and C. crocodilus, Paleosuchus trigonatus and Paleosuchus palpebrosus are very well differentiated and also show surprising haplotypic diversity in spite of their phenotypic similarity. J. Exp. Zool. 309A:588–599, 2008. © 2007 Wiley‐Liss, Inc.
Construction of X‐ray‐inducible promoters through cis‐acting element elongation and error‐prone polymerase chain reaction
Authors: Ogawa Ryohei , Lee Sung‐il , Kagiya Go , Hirano Hisao , Fukuda Shigekazu , Kondo Takashi , Kodaki Tsutomu
Published: December 2007

Background

A promoter that is activated by ionizing radiation may be a useful tool for cancer therapy since, with such a promoter, the therapeutic gene can be expressed only in cancer tissues by irradiation. An artificially constructed promoter is advantageous as natural promoters may have physiological limitations. However, reasonably designing a promoter is hampered by shortage of information about the relationship between the structure and properties of a promoter DNA.

Materials and methods

Binding sites of four transcription factors that were activated by radiation were randomly ligated and linked to a TATA‐box sequence to control the luciferase gene located downstream. Transiently transfected cancer cells with such a vector were exposed to X‐ray irradiation and enhancement of luciferase expression was assessed. To improve promoter sensitivity, mutations were randomly introduced into a constructed promoter by error‐prone polymerase chain reaction (epPCR).

Results

Of the 11 promoters constructed, the clone 11 promoter (clone 11 + TATA‐box) showed a 5‐fold enhancement 6 h after the 10 Gy X‐ray irradiation in HeLa cells. A mutant designated the clone 11‐9‐37 promoter generated through two steps of epPCR showed a sensitivity 4.8 times higher than the clone 11 promoter to the 10 Gy X‐rays, showing 21.6‐fold enhancement of luciferase expression. Clone 11 was composed of 16 cis‐acting elements, and the clone 11‐9‐37 promoter carried six point mutations.

Conclusion

A sensitively responsive promoter to radiation could be constructed using this method, possibly leading to the construction of a promoter of interest that could be applied for clinical use. Copyright © 2007 John Wiley & Sons, Ltd.
Prognostic value of bax, bcl‐2, and p53 staining in primary osteosarcoma
Authors: Kaseta Maria‐Kyriaki A. , Khaldi Lubna , Gomatos Ilias P. , Tzagarakis George P. , Alevizos Leonidas , Leandros Emmanuel , Papagelopoulos Panayiotis J. , Soucacos Panayiotis N.
Published: December 2007

Background and Objectives

To investigate the immunohistochemical expression of three apoptosis‐related genes (bax, bcl‐2, and p53) and apoptosis (TUNEL) in patients with primary osteosarcoma, and examine potential correlations between gene expression and clinicopathological characteristics in these patients.

Materials and Methods

Thirty‐five primary osteosarcoma specimens and 18 tissue specimens deriving from non‐malignant osseous lesions were immunohistochemically stained for bax, bcl‐2, and p53 proteins, while apoptosis was investigated by the TUNEL method. The results were statistically analyzed.

Results

P53, bax, and bcl‐2 protein expression was observed in 22 (62.9%), 29 (82.9%), and 18 (51.4%) osteosarcoma patients, respectively. Non‐specific positive TUNEL staining (±) was observed in two primary osteosarcoma cases (5.7%). None of the benign controls expressed any of the genes studied. None of the apoptosis‐related genes studied was able to predict overall or disease‐free survival in our group of patients. Nevertheless, increased bax/bcl‐2 protein expression ratio was associated with a decreased 4‐year survival and disease free survival (P = 0.0229 and P = 0.0370, respectively). Furthermore, all the patients who were bax(+)/bcl‐2(−)/p53(+) relapsed within the 4‐year follow‐up period (P = 0.0385).

Conclusions

The increased apoptotic rate as determined by an elevated bax/bcl‐2 protein expression ratio or by the bax(+)/bcl‐2(−)/p53(+) protein expression pattern, appears to identify groups of osteosarcoma patients with unfavorable prognosis. J. Surg. Oncol. 2008;97:259–266. © 2007 Wiley‐Liss, Inc.
Results of limb‐salvage surgery with vascular reconstruction for soft tissue sarcoma in the lower extremity: Comparison between only arterial and arterovenous reconstruction
Authors: Tsukushi Satoshi , Nishida Yoshihiro , Sugiura Hideshi , Nakashima Hiroatsu , Ishiguro Naoki
Published: December 2007

Background

Reports on vascular reconstruction in conjunction with limb salvage techniques for soft tissue sarcomas in the lower extremity have been published. The aim of this study was to investigate the necessity for venous reconstruction by comparing the results of arterial reconstruction alone and those of arteriovenous reconstruction.

Methods

Twenty‐five (6.7%) of 373 patients underwent vascular resections for lower limb soft tissue sarcomas. Only arterial reconstruction was performed for 12 patients. Arteriovenous reconstruction was performed for 13 patients. The clinical results, complications, and postoperative function were compared between only arterial reconstruction group and arteriovenous reconstruction group.

Results

Limb salvage was achieved in 92% of all cases. No local recurrence has been observed. Nineteen patients (76%) are continuously free of disease. Histopathologic examination of the specimens showed that blood vessels had been infiltrated in 24%. The mean Musculoskeletal Tumor Society score was 70%. There were no significant differences in complication rate and postoperative function between two groups.

Conclusions

Wide resection with vascular reconstruction for patients of soft tissue sarcomas involving major vessels in the lower limb provide long term local control and limb salvage. This study could not indicate the usefulness of additional venous reconstruction after vascular resection in the lower extremity. J. Surg. Oncol. 2008;97:216–220. © 2007 Wiley‐Liss, Inc.
High operative risk of cool‐tip radiofrequency ablation for unresectable pancreatic head cancer. John S, Anastasios D, Nikolaos M, Spiros K, Archodia V, Athanasios R, Athina C. 2007. J Surg Oncol 96: 89–90
Authors: Spiliotis John D. , Datsis Anastasios C. , Michalopoulos Nikolaos V. , Kekelos Spiros P. , Vaxevanidou Archodia , Rogdakis Athanasios G. , Christopoulou Athina N.
Published: December 2007

The article to which this erratum refers was published in J Surg Oncol (2007) 96: 89–90. © 2007 Wiley‐Liss, Inc.

In the original article by Spiliotis et al., the authors' first names and surnames were inverted. The authorship appears here in its correct format.
No mucosal escape of signet‐ring cell carcinoma for ten years in a patient with familial aggregation of gastric cancer
Authors: Tanis Pieter J. , Ten Kate Fiebo J.W. , van Lanschot J. Jan B.
Published: December 2007

A 31‐year‐old women with familial aggregation of gastric cancer had signet‐ring cell carcinoma in random biopsies from the gastric corpus. Surgery was initially refused by the patient. Total gastrectomy was performed 10 years later and pathological examination of the specimen still revealed only intramucosal carcinoma. Microsatellite instability or decreased E‐cadherin expression could not be identified. A missense mutation in the CDH1 gene was identified. She is alive without evidence of disease 6 years postoperatively. J. Surg. Oncol. 2008;97:294–296. © 2007 Wiley‐Liss, Inc.
Mixed ductal‐endocrine carcinoma derived from intraductal papillary mucinous neoplasm (IPMN) of the pancreas identified by human telomerase reverse transcriptase (hTERT) expression
Authors: Hashimoto Yasushi , Murakami Yoshiaki , Uemura Kenichiro , Hayashidani Yasuo , Sudo Takeshi , Ohge Hiroki , Sueda Taijiro , Shimamoto Fumio , Hiyama Eiso
Published: December 2007

We report a case of mixed ductal‐endocrine carcinoma derived from intraductal papillary mucinous neoplasm (IPMN) of the pancreas. The tumor presented intermingled exocrine and endocrine carcinomatous components and expressed intense human telomerase reverse transcriptase (hTERT), further confirming the malignant features. This pathologically unique tumor is the first case of mixed ductal‐endocrine carcinoma derived from pancreatic IPMN and telomerase activation could play a potential role in the neoplastic progression of mixed ductal‐endocrine carcinomas of the pancreas. J. Surg. Oncol. 2008;97:469–475. © 2007 Wiley‐Liss, Inc.
Laser Micro Processing
Authors: Gillner Arnold
Published: December 2007

The significance of micro processing technologies has seriously increased within the last years, since micro products and micro inspired properties even on large products open up new applications in several areas. Due to their advantages with selective processing capability, high speed and unbeatable process flexibility for a large variety of materials, laser processes have been established within micro technology as a versatile instrument for numerous applications.
Laser Applications in Solar Cell Manufacturing
Authors: Hendel Richard
Published: December 2007

Driven by the shortage of fossil fuels and increasing environmental pollution, photovoltaics is significantly gaining importance in energy generation. Extensive government subsidies in great industrial nations have triggered its growth. Also, more and more producers of solar cells appear on the market investing into modern, large scale production plants and innovative production technologies.
Laser Micro Processing of Semiconductors and Dielectrics
Authors: Weiler Sascha
Published: December 2007

In 2007 the semiconductor manufacturing industry is expected to make more than $250 billion gross revenue and invest over $40 billion in new equipment. The demand for cheaper and increasingly powerful end products, like PCs, Laptops and MP3 Players is the driving force for further development of production equipment. Barrier breaking picosecond lasers for direct ablation of semiconductors are paving the way for the next generation of such machinery.
The Whole is More Than the Sum of its Parts
Authors: Fries Thomas
Published: December 2007

Whether it is in semiconductors, nanotechnology or even in the field of laser and optics, the trend towards down‐scaling can be observed in nearly every industrial sector. Smaller structures lead to better performance, less weight and energy consumption or special properties when it comes to nanotechnology. Though, in order to design and produce these structures, R&D and production departments need flexible solutions for measuring surfaces with a high dynamic range from the sub‐nanometer to the meter.
CO2 Lasers for Flexible Food Packaging
Authors: Dinauer William R. , Gaebler Frank
Published: December 2007

Compact size and high reliability are key factors enabling digital converting systems that incorporate multiple lasers for high‐throughput cutting, perforating and scoring of flexible films.