bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallization behavior and spherulite growth rate of isotactic polypropylene in isotactic polypropylene/natural rubber based thermoplastic elastomers
Authors: Joseph Aju , Koch T. , Seidler S. , Thomas S. , Joseph K.
Published: April 2008

The melting and crystallization behavior of isotactic polypropylene/natural rubber (PP/NR) based thermoplastic elastomers (TPEs) were investigated using differential scanning calorimetry. The samples were scanned at a heating rate of 10°C/min under nitrogen atmosphere. The effects of blend ratio on the melting and crystallization characteristics of the blends were analyzed. Normalized crystallinity is unchanged by the addition of small amount of NR, but as the amount of rubber increases crystallinity increased for the 30/70 NR/PP and lowered for the 50/50 NR/PP blend system. Morphology of the blend was analyzed using scanning electron microscopy (SEM). Blend ratio showed a pronounced influence on the phase morphology of the NR/PP TPEs. As the amount of NR increases more than 50 wt % the system changes from dispersed to cocontinuous structure. Hot‐stage polarizing optical microscopy (POM) was used to study the radial growth of spherulite as a function of blend ratio, cooling rate, and crystallization temperature. Spherulite growth rate is marginally influenced by the rubber inclusions. The spherulite morphology observed under polarized optical microscopy is influenced by the blend morphology. It was found that for the cocontinuous 50/50 blend system, spherulites are much different from the usual appearance under polarized light. Attempts have been made to correlate the crystallization behavior with the morphology of the blend. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of a methyl methacrylate/ethyl acrylate/acrylic acid terpolymer to improve the homogeneity of ethylene–propylene–diene monomer rubber/poly(vinyl chloride) blends
Authors: Botros S. H. , Moustafa A. F. , Mansour S. H.
Published: April 2008

The emulsion terpolymerization of methyl methacrylate (MMA), ethyl acrylate (EA), and acrylic acid (AA) was carried out under a nitrogen atmosphere at 70°C. The final terpolymer conversion was determined gravimetrically. The synthesized MMA–EA–AA terpolymer was characterized with 1H‐NMR spectroscopy, thermal analysis, and gel permeation chromatography. Glass‐transition temperatures of the MMA–EA–AA terpolymer were determined with a differential scanning calorimeter. Ethylene–propylene–diene monomer rubber (EPDM)/poly(vinyl chloride) (PVC) blends were prepared with different blend ratios (10/90, 20/80, 30/70, 40/60, and 50/50) in the presence and absence of MMA–EA–AA as a compatibilizer. The morphology of those blends was examined with the aid of a scanning electron microscope. The scanning electron micrographs in the presence of the MMA–EA–AA terpolymer illustrated the disappearance of the macroscale phase separation of EPDM/PVC blends as a result of the incorporation of MMA–EA–AA into that blend, indicating an improvement of the homogeneity. The mechanical properties of the EPDM/PVC blend films and the dielectric properties of the melt blends were investigated. The swelling behavior of the cured blends in the brake fluid was also discussed. The results illustrated that the mechanical properties, the weight swelling values, and the dielectric constant values showed linear behavior versus the blend ratios after the incorporation of the terpolymer. However, those values showed deviations from linearity in the absence of the terpolymer. That, in turn, ensured the results obtained with the scanning electron microscope. The results reveal that the MMA–EA–AA terpolymer prepared can be used successfully to improve the homogeneity of EPDM/PVC blends used in hose and oil seal applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of unsaturated poly(ε‐caprolactone) with a new titanium alkoxide initiator
Authors: Xia Zhean , Zerroukhi Amar , Chalamet Yvan , Chen Jianding
Published: April 2008

Titanium alkoxides are widely used in the ring‐opening polymerization of ε‐caprolactone. In this study, functional poly(ε‐caprolactone) was synthesized with a new titanium initiator by a two‐step procedure: First, the titanium initiator, with an unsaturated group, was prepared by a classical organic reaction between 2‐hydroxyethylmethacrylate or 2‐allyloxyethanol with titanium tetrapropoxide; then, we initiated the polymerization of the ε‐caprolactone monomer in a glass reactor or twin‐screw extruder. By means of NMR spectroscopy, the structures of the initiators and polymers were determined. When 2‐hydroxyethylmethacrylate was used, there was a side reaction (transesterification) during the preparation of the initiator, and so it was impossible to obtain the expected product. With 2‐allyloxyethanol, the designed titanium initiator was synthesized with high purity, and the allyl moiety remained intact after the polymerization of ε‐caprolactone. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Cationic copolymerization of epoxy siloxane monomer with liquid poly‐butadiene and its light emitting diode encapsulation
Authors: Morita Yasumasa , Tajima Seitarou , Suzuki Hiroshi , Sugino Hiroaki
Published: April 2008

A novel epoxy siloxane hybrid was prepared using epoxy siloxane monomers of 1,3‐bis[2‐(3‐{7‐oxabicyclo[4.1.0]heptyl})ethyl]‐tetramethyldisiloxane (BEPDS) with hydroxyl terminated hydrogenated polybutadiene (GI‐1000), in different proportions. Apparent polymerization reactivity was decreased with increasing GI‐1000 concentration but the normalized reactivity per epoxy group was slightly increased due to reaction between hydroxyl group and epoxy group. Increasing GI‐1000 concentration showed significant flexibility improvement in epoxy siloxane hybrid. At 30 wt % of GI‐1000 addition, glass transition temperature was decreased from 116 to 21°C and shore D hardness was decreased from 75 to 46.5% weight loss temperature of these epoxy siloxane hybrid was decreased with increasing GI‐1000 concentration, whereas thermal discoloration was increased. LED encapsulation with this epoxy siloxane demonstrated no crack when GI‐1000 was 30 wt % or more. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation and characterization of poly(methyl methacrylate) beads
Authors: Holmes Rohan L. , Burford Robert P. , Bertram Christopher D.
Published: April 2008

For fluid‐dynamic experiments involving concentrated suspensions and complex geometries, particles which are neutrally buoyant and which have the same refractive index as both the suspending fluid and the bounding container are needed. Poly(methyl methacrylate) (PMMA) particles can meet these requirements simultaneously. Therefore monodisperse beads with the refractive index and density of pure PMMA were needed. For comparison with particle migration theory, it is also important that bead size and sphericity be accurately controlled. In our fluid mechanics experiments, 500‐μm diameter was required, a size where suspension polymerization is suitable. This article describes the controlled formation of PMMA beads in substantial quantities with desired size and a narrow particle size distribution. Reaction scale‐up using a 2‐L Büchi reactor allowed batch yields of 200 g of PMMA beads with desired shape and size. However, microcavities reduced bead density and optical clarity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and viscosity of hydrophobically modified polymers containing dendritic segments
Authors: Ali Shaikh A. , Umar Yunusa , Al‐Muallem Hasan A. , Abu‐Sharkh Basel F.
Published: April 2008

The cycloterpolymerizations of a newly synthesized dendritic quadruple‐tailed hydrophobic diallylammonium chloride with the hydrophilic monomer N,N‐diallyl‐N‐carboethoxymethylammonium chloride and sulfur dioxide afforded a series of water‐soluble cationic polyelectrolytes (CPEs) containing various proportions (0–1 mol %) of the hydrophobe. At a shear rate of 0.36 s−1 at 30°C, salt‐free water solutions of the CPEs (4 g/dL) containing 0, 0.35, 0.53, 0.65, and 0.93 mol % of the hydrophobe had apparent viscosity values of 140, 1200, 180,000, 308,000, and 858,000 cps, respectively. The study clearly demonstrated an increase in the viscosity values with increasing incorporation of the hydrophobes. The CPEs on acidic hydrolysis of the pendant ester groups gave corresponding pH‐responsive cationic acid salts, which upon treatment with NaOH, were converted to the polybetaines (PBs), anionic polyelectrolytes (APEs), and PB/APEs containing various proportions of PB and APE fractions in the polymer chain. The effects of charge type and charge density on the polymer chain were investigated. Polymer surfactant interactions were investigated with the cationic surfactant cetyltrimethylammonium bromide; a considerable increase in the viscosity values of the CPE was observed in the presence of the surfactant. The superior viscosity behavior for the polymers containing the quadruple‐tailed hydrophobe was attributed to the blocky nature of the comonomer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of 3′,4′‐disubstituted terthiophenes—Characterization and electropolymerization. II. 3′‐bromo‐4′‐thienyl‐2,2′:5′,2′‐terthiophene and 3′,4′‐diphenyl‐2,2′:5′,2′‐terthiophene in photovoltaic displays
Authors: Vélez J. H. , Díaz F. R. , del Valle M. A. , Bernéde J. C. , Soto J. P.
Published: April 2008

In a previous work 3′,4′‐dibromo substituted polythiophene film was used to produce an electronic device with photovoltaic characteristic but only 0.006% yield was achieved. In an effort to understand the reason of this low‐yield, we intend to elucidate the effect of substituents of terthiophene compounds on the morphological characteristics and conductivity of the electrochemical deposit. Thus, in this article we describe the electrochemical properties of thin films of poly(3′,4′‐diphenyl‐2,2′:5′,2″‐terthiophene), and poly(3′‐bromo‐4′‐thienyl‐2,2′:5′,2″‐terthiophene), the studies of electropolymerization using cyclic voltammetry, the determination of nucleation and growth mechanism using potential steps, and the morphology. Furthermore, a ZnO/Polymer/PTCDA/Li/Al photovoltaic cells have been devised and their I–V characteristics studied in the presence and in the absence of light. Incorporation of 3,4‐9,10‐tetracarboxylic dianhydride, PTCDA, as acceptor, induces a wider absorption spectrum in the visible region. Study of the photovoltaic efficiency, that increased with a decrease of the polymeric coating thickness, which in turn, is related to the number of voltammetric cycles, was also accomplished, but the desired thickness was never obtained without missing the electronic properties. Thus, even if the polymeric layer had the appropriate structure, this study corroborates that, to prepare the deposit, the electrochemical parameters must be previously controlled so as to obtain the thickness and morphology that render the best response. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Local citation analysis, publishing and reading patterns: Using multiple methods to evaluate faculty use of an academic library's research collection
Authors: Wilson Concepción S. , Tenopir Carol
Published: April 2008

This study assessed the intermix of local citation analysis and survey of journal use and reading patterns for evaluating an academic library's research collection. Journal articles and their cited references from faculties at the University of New South Wales were downloaded from the Web of Science (WoS) and journal impact factors from the Journal Citation Reports. The survey of the University of New South Wales (UNSW) academic staff asked both reader‐related and reading‐related questions. Both methods showed that academics in medicine published more and had more coauthors per paper than academics in the other faculties; however, when correlated with the number of students and academic staff, science published more and engineering published in higher impact journals. When “recalled” numbers of articles published were compared to “actual” numbers, all faculties over‐estimated their productivity by nearly two‐fold. The distribution of cited serial references was highly skewed with over half of the titles cited only once. The survey results corresponded with U.S. university surveys with one exception: Engineering academics reported the highest number of article readings and read mostly for research related activities. Citation analysis data showed that the UNSW library provided the majority of journals in which researchers published and cited, mostly in electronic formats. However, the availability of non‐journal cited sources was low. The joint methods provided both confirmatory and contradictory results and proved useful in evaluating library research collections.
Emerging biorefinery markets: global context and prospects for Latin America
Authors: Blanco‒Rosete Sergio , Webb Colin
Published: April 2008

The production of chemicals from renewable raw materials is expected to take place in a biorefinery system. This review provides a historical background of previous efforts to establish chemical production based on renewable raw materials. Considering the current efforts and strategies to develop biorefineries in Europe and the USA the prospects for Latin America are explored. Even though some Latin American governments have started legislating for the inclusion of renewable energies, there is little evidence they have envisaged plans to explore the development of biorefineries. Developing biorefineries in the region would require an assessment of current agricultural means of production with a view to taking advantage of the varied climate and wide range of crops that could serve as raw materials. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd
On‐line extraction coupled with liquid chromatography tandem mass spectrometry for quantitation of pravastatin and its metabolite in human serum
Authors: Wang Xiaodong , Wang Yongcheng
Published: April 2008

A high‐throughput bioanalytical method for simultaneous quantitation of pravastatin and its metabolite (M1) in human serum was developed and validated using on‐line extraction following liquid chromatography tandem mass spectrometry (LC‐MS/MS). The on‐line extraction was accomplished by the direct injection of a 50 µL serum sample, mixed 4:1 with an aqueous internal standard solution, into one of the extraction columns with aqueous 1 mm formic acid at flow rate of 3 mL/min. The separation and analysis were achieved by back‐eluting the analytes from the extraction column and the analytical column to the mass spectrometer with an isocratic mobile phase consisting of 62% aqueous 1 mm formic acid and 38% acetonitrile at a flow rate of 0.8 mL/min. The second extraction column was being equilibrated while the first column was being used for analysis, and vice versa. The standard curve range was 0.500–100 ng/mL for pravastatin and M1. The lower limit of quantitation, 0.500 ng/mL for all the analytes, was achieved when 50 µL of human serum was used. The intra‐ and inter‐day precisions were within 7.4%, and the accuracy was between 95 and 103%. The on‐line extraction was finished in 0.5 min and total analysis time was 2.5 min per sample. Copyright © 2008 John Wiley & Sons, Ltd.
Unsolved motility looking for answer
Authors: Tamm Sidney L.
Published: April 2008

A rod‐like axostyle complex turns the anterior end of a termite flagellate, including the plasma membrane, continually in the same direction relative to the rest of the cell at speeds up to ∼1 Hz. This motility provides direct visual evidence for the fluid nature of cell membranes. Torque is generated along the length of the axostyle complex by an unknown mechanism. Here I describe findings not published before and promising experiments that may help to solve this remarkable motility. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Towards Small‐Molecule CXCR3 Ligands with Clinical Potential
Authors: Wijtmans Maikel , Verzijl Dennis , Leurs Rob , de Esch Iwan J. P. , Smit Martine J.
Published: April 2008

The CXCR3 chemokine receptor was first discovered in 1996 and has been shown to play an important role in several diseases, most of which are related to inflammation. This review describes in detail the development of small CXCR3 ligands and their therapeutic potential. Classes of CXCR3 antagonists with strikingly variable core structures have emerged. Some of these compounds have confirmed the beneficial role of CXCR3 antagonism in animal models of disease. One of the compounds, AMG487, progressed to Phase II clinical trials but has been withdrawn because of lack of efficacy. New antagonist classes are being developed to reveal the full therapeutic potential of CXCR3.
Pathologic stage is most prognostic of disease‐free survival in locally advanced rectal cancer patients after preoperative chemoradiation
Authors: Quah Hak‐Mien , Chou Joanne F. , Gonen Mithat , Shia Jinru , Schrag Deborah , Saltz Leonard B. , Goodman Karyn A. , Minsky Bruce D. , Wong W. Douglas , Weiser Martin R.
Published: April 2008

BACKGROUND.

Preoperative chemoradiation is the standard treatment for locally advanced rectal cancer. However, it is uncertain whether pretreatment clinical stage, degree of response to neoadjuvant treatment, or pathologic stage is the most reliable predictor of outcome. This study compared various staging elements and treatment‐related variables to identify which factors or combination of factors reliably prognosticates disease‐free survival in rectal cancer patients receiving neoadjuvant combined modality therapy.

METHODS.

From a prospectively maintained single institution database, 342 consecutive patients with locally advanced rectal cancer staged by endorectal ultrasound were identified. Patients underwent rectal resection 4 to 8 weeks after a 5.5‐week course of pelvic radiotherapy/concurrent chemotherapy. The degree of tumor regression was histologically graded on each resected specimen using a previously reported response scale of 0% to 100%. Predictive models of disease‐free survival were created utilizing available pretherapy and postoperative staging elements in addition to the degree of tumor regression noted histologically. Model accuracy was measured and compared by concordance index, with 95% confidence interval (CI).

RESULTS.

Stratifying patients by degree of tumor regression predicted outcome with a concordance index of 0.65 (95% CI, 0.59–0.71), which was significantly better than models using preoperative stage elements (concordance index of 0.54; 95% CI, 0.50–0.58). However, the model found to be most predictive of disease‐free survival stratified patients by final pathologic T classification and N classification elements, with a concordance index of 0.75 (95% CI, 0.70–0.80).

CONCLUSIONS.

Tumor response to preoperative therapy is a strong predictor of disease‐free survival. However, outcome is most accurately estimated by final pathologic stage, which is influenced by both preoperative stage and response to therapy. Cancer 2008. © 2008 American Cancer Society.
Preconditioners for the indefinite linear system arising from the hp discretization of Maxwell's equations
Authors: Ledger P. D.
Published: April 2008

This paper describes a preconditioner for the iterative solution to the indefinite linear equation system that is obtained when the vector wave equation is discretized by higher‐order H(curl)‐conforming finite elements. The preconditioner is based on a decomposition of the H(curl)‐conforming functions into blocks comprising lower‐order functions and higher‐order functions. Fast convergence is obtained when the grid spacing is sufficiently small. A method for selecting suitable grid spacings is proposed and a series of numerical examples are included to demonstrate the effectiveness of the approach. Copyright © 2008 John Wiley & Sons, Ltd.
Quantitative Analysis of Alpha‐D‐glucose in an Ionic Liquid by Using Infrared Spectroscopy
Authors: Kiefer Johannes , Obert Katharina , Bösmann Andreas , Seeger Thomas , Wasserscheid Peter , Leipertz Alfred
Published: April 2008

The applicability of infrared (IR) spectroscopy for quantitative concentration measurements in mixtures of carbohydrates and ionic liquids (ILs) is investigated. The compound 1‐ethyl‐3‐methylimidazolium acetate, [EMIM][OAc]—an “enzyme‐friendly” ionic liquid with great application potential in the dissolution of various biomasses—is used as solvent in combination with alpha‐D‐glucose. Our study establishes a new way to monitor the concentration of sugars in ILs, thus providing a convenient method to follow the kinetics of, for example, enzymatic reactions in [EMIM][OAc]. As a first step, we present the IR spectrum of pure [EMIM][OAc] (this constitutes the first vibrational study of this particular IL). Although numerous lines overlap in the fingerprint region of the spectrum, characteristic features can be assigned to the corresponding vibrational modes of both ions. Secondly, we study different mixtures of the IL with alpha‐D‐glucose (in the concentration range: 0–20 mass % glucose) and analyze them by means of IR spectroscopy, followed by computational methods, thus demonstrating the great potential of this spectroscopic technique in quantitative measurements.
Generation of a reporter mouse line expressing Akt and EGFP upon Cre‐mediated recombination
Authors: Elghazi Lynda , Weiss Aaron J , Gould Aaron P , Hegedus Balazs , Gutmann David H. , Bernal‐Mizrachi Ernesto
Published: April 2008

The serine‐threonine kinase Akt regulates multiple biological processes. An important strategy to study Akt signaling in different tissues is targeted activation of this pathway in vivo. The current studies describe the generation of a mouse model that combines a double reporter system with activation of a constitutively active form of Akt1 (caAkt) in a Cre‐dependent manner. Before Cre recombination, these mice express LacZ during development as well as in most adult tissues. After Cre‐mediated excision of the LacZ reporter, functionality of the transgene was demonstrated by expression of the caAkt mutant along with the second reporter, EGFP in different pancreatic compartments and in the nervous system. This animal model provides a critical reagent for assessing the effects of Akt activation in specific tissues. The lineage‐tracing properties provide a useful tool to study the role of Akt signaling in regulation of differentiation programs during development and plasticity of mature tissues. genesis 46:256–264, 2008. © 2008 Wiley‐Liss, Inc.
Slingshot‐3 dephosphorylates ADF/cofilin but is dispensable for mouse development
Authors: Kousaka Kazuyoshi , Kiyonari Hiroshi , Oshima Naoko , Nagafuchi Akira , Shima Yasuyuki , Chisaka Osamu , Uemura Tadashi
Published: April 2008

Actin‐depolymerizing factor (ADF) and cofilin constitute a family of key regulators of actin filament dynamics. ADF/cofilin is inactivated by phosphorylation at Ser‐3 by LIM‐kinases and reactivated by dephosphorylation by Slingshot (SSH) family phosphatases. Defects in LIM kinases or ADF/cofilin have been implicated in morbidity in human or mice; however, the roles of mammalian SSH in vivo have not been addressed. In this study, we examined the endogenous expression of each mouse SSH member in various cell lines and tissues, and showed that SSH‐3L protein was strongly expressed in epithelial cells. Our structure–function analysis of SSH‐3L suggested the possibility that the C‐tail unique to SSH‐3L negatively regulates the catalytic activity of this phosphatase. Furthermore we made ssh‐3 knockout mice to examine its potential in vivo roles. Unexpectedly, ssh‐3 was not essential for viability, fertility, or development of epithelial tissues; and ssh‐3 did not genetically modify the corneal disorder of the corn1/ADF/destrin mutant. genesis 46:246–255, 2008. © 2008 Wiley‐Liss, Inc.
The development of the childhood retrospective perfectionism questionnaire (CHIRP) in an eating disorder sample
Authors: Southgate Laura , Tchanturia Kate , Collier David , Treasure Janet
Published: April 2008

This investigation explored the prevalence and predictive value of childhood obsessive‐compulsive personality traits (OCPTs) in the development of eating disorders (EDs) using a novel retrospective questionnaire. To reduce bias associated with retrospective self‐report data, an identical informant version of the questionnaire was also utilised. Substantial test–retest and inter‐rater reliabilities were found for the questionnaire, as well as concordant validity with the semi‐structured interview from which it was derived. Participants with an ED (n = 246) endorsed more childhood behaviours reflecting OCPTs than the control group (n = 89). This was mirrored in the informant report data (n = 93). The prevalence rate for each OCPT in childhood was significantly higher in the total ED sample compared to the control group. Both proband and informant reports of childhood traits predict the later development of an ED according to a strong dose–response relationship. The potential utility of this measure in future retrospective and prospective research studies is highlighted. Copyright © 2008 John Wiley & Sons, Ltd and Eating Disorders Association.
Accurate closed‐form approximations for the performance of equal gain combining diversity systems in Nakagami fading channels
Authors: Hu Jeremiah , Beaulieu Norman C.
Published: April 2008

Accurate closed‐form approximations for the distribution and density of the signal envelope at the output of L‐branch equal gain combining (EGC) receivers in Nakagami fading channels are derived. These expressions are used to analyse the probability of error of an L‐branch predetection EGC diversity system operating in different fading conditions. Coherent and noncoherent binary signalling as well as coherent M‐ary signalling are considered. In addition, a closed‐form expression for the outage probability of these systems is derived. These closed‐form expressions permit rapid evaluation of the performance of EGC diversity systems without resorting to numerical integration as required by previous solutions. Copyright © 2008 John Wiley & Sons, Ltd.
Adaptive finite element approximation of coupled flow and transport problems with applications in heat transfer
Authors: Larson Mats G. , Söderlund Robert , Bengzon Fredrik
Published: April 2008

In this paper we develop an adaptive finite element method for heat transfer in incompressible fluid flow. The adaptive method is based on an a posteriori error estimate for the coupled problem, which identifies how accurately the flow and heat transfer problems must be solved in order to achieve overall accuracy in a specified goal quantity. The a posteriori error estimate is derived using duality techniques and is of dual weighted residual type. We consider, in particular, an a posteriori error estimate for a variational approximation of the integrated heat flux through the boundary of a hot object immersed into a cooling fluid flow. We illustrate the method on some test cases involving three‐dimensional time‐dependent flow and transport. Copyright © 2008 John Wiley & Sons, Ltd.
On pressure separation algorithms (PSepA) for improving the accuracy of incompressible flow simulations
Authors: Turek S. , Ouazzi A. , Hron J.
Published: April 2008

We investigate a special technique called ‘pressure separation algorithm’ (PSepA) (see Applied Mathematics and Computation 2005; 165:275–290 for an introduction) that is able to significantly improve the accuracy of incompressible flow simulations for problems with large pressure gradients. In our numerical studies with the computational fluid dynamics package FEATFLOW (www.featflow.de), we mainly focus on low‐order Stokes elements with nonconforming finite element approximations for the velocity and piecewise constant pressure functions. However, preliminary numerical tests show that this advantageous behavior can also be obtained for higher‐order discretizations, for instance, with Q2/P1 finite elements. We analyze the application of this simple, but very efficient, algorithm to several stationary and nonstationary benchmark configurations in 2D and 3D (driven cavity and flow around obstacles), and we also demonstrate its effect to spurious velocities in multiphase flow simulations (‘static bubble’ configuration) if combined with edge‐oriented, resp., interior penalty finite element method stabilization techniques. Copyright © 2008 John Wiley & Sons, Ltd.
A lattice Boltzmann‐BGK algorithm for a diffusion equation with Robin boundary condition—application to NMR relaxation
Authors: Hiorth A. , a Lad U. H. , Evje S. , Skjæveland S. M.
Published: April 2008

We present a lattice Boltzmann‐BGK (LBGK) algorithm for a diffusion equation together with a Robin boundary condition, which we apply in the case of nuclear magnetic resonance relaxation. The boundary condition we employ is independent of the direction of the wall. This makes the algorithm very suitable for complicated geometries, such as porous media. We discuss the effect of lattice topology by using, respectively, an eight‐speed and a four‐speed lattice. The numerical algorithm is compared with analytical results for a square and an equilateral triangle. The eight‐speed lattice performs well in both cases. The four‐speed lattice performs well for the square, but fails in the case of an equilateral triangle. Comparison with a random walk algorithm is also included. The LBGK algorithm presented here can also be used for a convective diffusion problem if the speed of the fluid can be neglected close to the boundary. Copyright © 2008 John Wiley & Sons, Ltd.
Mild brain ischemia induces unique physiological properties in striatal astrocytes
Authors: Wang Li‐Ping , Cheung Giselle , Kronenberg Golo , Gertz Karen , Ji Shengbo , Kempermann Gerd , Endres Matthias , Kettenmann Helmut
Published: April 2008

We studied the properties of GFAP‐expressing cells in adult mouse striatum using acute brain slices from transgenic animals expressing EGFP under GFAP promoter. Under physiological conditions, two distinct populations of GFAP‐EGFP cells could be identified: (1) brightly fluorescent cells had bushy processes, passive membrane properties, glutamate transporter activity, and high gap junction coupling rate typical for classical astrocytes; (2) weakly fluorescent cells were characterized by thin, clearly distinguishable processes, voltage‐gated currents, complex responses to kainate, and low coupling rate reminiscent of an astrocyte subtype recently described in the hippocampus. Mild focal cerebral ischemia confers delayed neuronal cell death and astrogliosis in the striatum. Following middle cerebral artery occlusion and reperfusion, brightly fluorescent cells were the dominant GFAP‐EGFP population observed within the ischemic lesion. Interestingly, the majority of these cells expressed voltage‐gated channels, showed complex responses to kainate, and a high coupling rate exceeding that of brightly fluorescent control cells. A minority of cells had passive membrane properties and was coupled less compared with passive control cells. We conclude that, in the adult striatum, astrocytes undergo distinct pathophysiological changes after ischemic insults. The dominant population in the ischemic lesion constitutes a novel physiological phenotype unlike any normal astrocyte and generates a large syncytium which might be a neuroprotective response of reactive astrocytes. © 2008 Wiley‐Liss, Inc.
HSP27 mediates SPARC‐induced changes in glioma morphology, migration, and invasion
Authors: Golembieski William A. , Thomas Stacey L. , Schultz Chad R. , Yunker Christopher K. , McClung Heather M. , Lemke Nancy , Cazacu Simona , Barker Thomas , Sage E. Helene , Brodie Chaya , Rempel Sandra A.
Published: April 2008

Secreted protein acidic and rich in cysteine (SPARC) regulates cell–extracellular matrix interactions that influence cell adhesion and migration. We have demonstrated that SPARC is highly expressed in human gliomas, and it promotes brain tumor invasion in vitro and in vivo. To further our understanding regarding SPARC function in glioma migration, we transfected SPARC‐green fluorescent protein (GFP) and control GFP vectors into U87MG cells, and assessed the effects of SPARC on cell morphology, migration, and invasion after 24 h. The expression of SPARC was associated with elongated cell morphology, and increased migration and invasion. The effects of SPARC on downstream signaling were assessed from 0 to 6 h and 24 h. SPARC increased the levels of total and phosphorylated HSP27; the latter was preceded by activation of p38 MAPK and inhibited by the p38 MAPK inhibitor SB203580. Augmented expression of SPARC was correlated with increased levels of HSP27 mRNA. In a panel of glioma cell lines, increasing levels of SPARC correlated with increasing total and phosphorylated HSP27. SPARC and HSP27 were colocalized to invading cells in vivo. Inhibition of HSP27 mRNA reversed the SPARC‐induced changes in cell morphology, migration, and invasion in vitro. These data indicate that HSP27, a protein that regulates actin polymerization, cell contraction, and migration, is a novel downstream effector of SPARC‐regulated cell morphology and migration. As such, it is a potential therapeutic target to inhibit SPARC‐induced glioma invasion. © 2008 Wiley‐Liss, Inc.
AT1receptor inhibition prevents astrocyte degeneration and restores vascular growth in oxygen‐induced retinopathy
Authors: Downie Laura E. , Pianta Michael J. , Vingrys Algis J. , Wilkinson‐Berka Jennifer L. , Fletcher Erica L.
Published: April 2008

We investigated the effect of receptor blockade induced by an angiotensin II type‐1 receptor antagonist (AT1‐RB) on glial and vascular changes in oxygen‐induced retinopathy (OIR), a model of retinopathy of prematurity (ROP). OIR was induced in Sprague‐Dawley rats by exposure to 80% oxygen from postnatal (P) days 0–11, followed by 7 days in room air. Control animals were in room air for the entire duration. One cohort of OIR and control pups received the AT1‐RB valsartan (40 mg/kg/day intraperitoneal) from P11 to P18. The vascular response was examined immunocytochemically using retinal wholemounts and vertical sections labeled with endothelial (Isolectin‐B4) and pericyte (NG2, desmin) markers. Glial cell changes were assessed by measuring cell numbers and immunoreactivity (S100β, connexin‐26, and glial fibrillary acidic protein). OIR resulted in extensive intravitreal neovascularization and under‐development of the outer vascular plexus. Pericyte numbers were not significantly affected in OIR, although pericyte‐endothelial (desmin‐IB4) interactions were impaired. Peripheral astrocyte degeneration occurred between P11 and P13 with prominent Müller cell reactivity at P18. Valsartan imparted a protective effect on glia and blood vessels in OIR. At P18, valsartan‐treated OIR retinae showed significantly greater astrocyte survival, improved revascularization of the retina, and reduced preretinal neovascularization and Müller cell reactivity. This study identifies a glio‐vascular protective effect with AT1‐RB in OIR. © 2008 Wiley‐Liss, Inc.
Developmental profile and mechanisms of GABA‐induced calcium signaling in hippocampal astrocytes
Authors: Meier Silke D. , Kafitz Karl W. , Rose Christine R.
Published: April 2008

GABA (γ‐aminobutyric acid) is a transmitter with dual action. Whereas it excites neurons during the first week of postnatal development, it represents the major inhibitory transmitter in the mature brain. GABA also activates astrocytes by binding to ionotropic (GABAA) and metabotropic (GABAB) receptors. This results in glial calcium transients which can induce the release of gliotransmitters, rendering GABA an important mediator of neuron‐glia interaction. Using whole‐cell patch‐clamp and ratiometric calcium imaging in hippocampal slices from rats at postnatal days 3–34, we have analyzed the developmental profile as well as the cellular mechanisms of calcium signals induced by GABAA and GABAB receptor activation in astrocytes. We found that GABA‐evoked glial calcium transients are mediated by both GABAA and GABAB receptors. Throughout development, GABAA‐receptor activation resulted in immediate calcium transients in the vast majority of astrocytes, most likely by influx of calcium through voltage‐gated calcium channels. GABAB receptor activation, in contrast, resulted in delayed calcium transients, which were blocked following depletion of intracellular calcium stores and during persistent activation of heterotrimeric G‐proteins. GABAB receptor‐mediated calcium signals exhibited a clear developmental profile with less than 10% of astrocytes responding at P3 or P32–34, and about 60% of cells between P11 and P15. Our data thus indicate that GABAB receptor‐mediated calcium transients are due to calcium release from intracellular stores following G‐protein activation. Moreover, GABAB receptor‐mediated calcium signaling in astrocytes preferentially occurs at a period during postnatal development when hippocampal networks are established. © 2008 Wiley‐Liss, Inc.
Cancer of the tonsil presenting as central nervous system metastasis: A case report
Authors: Dobelbower Michael C. , Nabell Lisle , Markert James , Carroll William , Said‐Al‐Naief Nasser , Meredith Ruby
Published: April 2008

Background

Metastases from tonsilar cancers are uncommon, usually found in the lung and less commonly in the bone, liver, and mediastinal sites. Only approximately 20% of patients die from distant metastasis. Central nervous system (CNS) metastases usually appear later in the course of the disease, with only 1% to 2% of patients developing metastasis involving the CNS in the course of their disease. Patients seen with symptomatic CNS lesions are rare.

Methods and Results

A case report is presented of a patient seen with signs and symptoms of CNS disease from an isolated CNS metastasis. The primary site was ultimately determined to be of tonsilar origin. The patient's treatment and outcome are discussed.

Conclusions

Tonsilar cancers seen with signs and symptoms of CNS disease is a rare event. The benefit of aggressive treatment of isolated CNS metastasis from head and neck cancers will likely be gained from case reports because the incidence is quite low. © 2008 Wiley Periodicals, Inc. Head Neck, 2009
Comparison of sensory recovery and morphologic change between sensate and nonsensate flaps in oral cavity and oropharyngeal reconstruction
Authors: Kim Jin Hwan , Rho Young Soo , Ahn Hwoe Young , Chung Chul Hoon
Published: April 2008

Background

Sensory recovery after oral cavity and oropharyngeal reconstruction is 1 of the most important goals of free flap reconstruction. The aim of this study was to compare sensory recovery of sensate and nonsensate free flaps and to evaluate the morphologic differences between sensate and nonsensate free flaps.

Methods

A total of 27 cases of radial forearm free flap reconstruction after oral cavity and oropharyngeal cancer resection were included in this study. Fifteen flaps were sensate flaps, and the other 12 flaps were nonsensate flaps. The sensory recovery was evaluated in 5 subjective senses: light tough, deep pressure, pain, warm, and cold senses. The 2‐point discriminations were also recorded. For morphologic evaluation, the shapes of nerve fibers and nerve fiber bundles were observed and counted after immunohistochemical stains with S‐100 protein and neuron‐specific enolase and observed with transmission electron microscope.

Results

The scores of the 5 subjective senses in the sensate flaps and 2‐point discrimination capabilities were significantly higher than those in the nonsensate flaps (p <.05). The number and the shape of the nerve fibers in the sensate flaps were more prominent (p <.05).

Conclusion

There were significant differences in sensory recovery between sensate and nonsensate flaps in oral cavity and oropharyngeal reconstruction, and the nerve fibers were larger, better arranged, and more numerous in sensate than nonsensate flaps. © 2008 Wiley Periodicals, Inc. Head Neck, 2008
A review of the micronutrient intervention cost literature: program design and policy lessons
Authors: Fiedler John L. , Sanghvi Tina G. , Saunders Margaret K.
Published: April 2008

Since the 1993 publication of Disease Control Priorities in Developing Countries and World Development Report: Investing in Health, micronutrient fortification and supplementation interventions have been recognized as being among the most cost‐effective public health interventions. This paper reviews nearly 100 studies of the cost of micronutrient interventions. The literature contains enormous variation in the estimated costs of these programs due to differences in program structure, delivery systems and a host of country‐specific factors, differences in the studies' objectives, designs and costing methodologies. The most diverse estimates reported are those of vitamin A supplementation programs, where estimates vary by a factor of more than 1000. The costs of fortification programs, too, vary substantially from a factor of two for iodine, six for iron, and 15 for vitamin A fortification. As the magnitude of these variations suggests, the bulk of these studies are idiosyncratic, and their results are not directly comparable. The review highlights the need for greater specificity in discourse about these programs, and for greater transparency about cost estimation methods. The review provides several insights: (1) average costs are several‐fold higher than has traditionally been maintained; (2) fortificants account for 80% of annual, incremental costs of vitamin A fortification; (3) whereas 70% of those of vitamin A supplementation programs are personnel; (4) the imprecision of food fortification coverage and impact estimates owes primarily to the paucity of food consumption data. Addressing the food consumption information gap is an essential next step to improving micronutrient program policies: to better targeting programs and to devising more cost‐effective program portfolio mixes. Cost studies have a largely unrealized potential role to play in increasing program efficiency, coverage, and effectiveness. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of craving and withdrawal among four combination nicotine treatments
Authors: Schneider Nina G. , Cortner Chris , Gould Jessica L. , Koury Margaret A. , Olmstead Richard E.
Published: April 2008

Objective

To assess the appearance of craving and withdrawal among four combination nicotine replacement treatments (NRTs).

Methods

In a crossover trial of NRT preferences, 27 smokers tested 4 combinations of nicotine treatments: 2 mg/4 mg gums + 15 mg patch, 2 mg/4 mg lozenges + 15 mg patch, inhalers + 15 mg patch, and 10 + 15 mg double patch (∼25 mg). Overnight abstinence was required prior to ½ day testing of each combination. Combination NRTs were used for ∼6 h/day. Subjects resumed smoking each afternoon. For this report, we used the Smoker Anchored Withdrawal Grid to look at craving and withdrawal scores over 5 days of testing (smoking baseline + four treatment days).

Results

“Urge to smoke” and “total withdrawal” showed a rise from baseline to NRT use for the double patch but not for the three acute + patch conditions. Lozenge/patch scores did not rise from baseline for “craving” and “miss a cigarette” but did for gum/patch, inhaler/patch, and double patch. The best relief occurred for NRTs of choice.

Conclusion

This was a small but suggestive finding regarding the potential of patch plus adjunct ad lib NRT. With little data on relief with NRT combinations, more systematic tests are needed. Published in 2008 by John Wiley & Sons, Ltd.
Ultrahigh molecular weight polyethylene wear debris inhibits osteoprogenitor proliferation and differentiation in vitro
Authors: Chiu Richard , Ma Ting , Smith R. Lane , Goodman Stuart B.
Published: April 2008

Polyethylene wear debris induces progressive osteolysis by increasing bone degradation and suppressing bone formation. Polyethylene particles inhibit the function of mature osteoblasts, but whether polyethylene particles also interfere with the proliferation and differentiation of osteoprogenitor cells is unknown. In this study, we investigated the effects of ultrahigh molecular weight polyethylene (UHMWPE) particles on the osteogenic activity of primary murine bone marrow osteoprogenitors and MC3T3‐E1 preosteoblastic cells in vitro. Submicron‐sized UHMWPE particles generated from wear simulator tests were isolated from serum‐containing solution by density gradient centrifugation. The particles were coated onto the surface of culture wells at concentrations of 0.038, 0.075, 0.150, 0.300, and 0.600% v/v in a layer of type I collagen matrix. Primary murine bone marrow cells and MC3T3‐E1 preosteoblasts were seeded onto the particle‐collagen matrix and induced to differentiate in osteogenic medium for 20 days. Exposure of both cell populations to UHMWPE particles resulted in a dose‐dependent decrease in mineralization, proliferation, alkaline phosphatase activity, and osteocalcin production when compared with control cells cultured on collagen matrix without particles. Complete suppression of osteogenesis was observed at particle concentrations ≥0.150% v/v. This study demonstrated that UHMWPE particles inhibit the osteogenic activity of osteoprogenitor cells, which may result in reduced periprosthetic bone regeneration and repair. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
In vivo evaluation of a multiphased scaffold designed for orthopaedic interface tissue engineering and soft tissue‐to‐bone integration
Authors: Spalazzi Jeffrey P. , Dagher Elias , Doty Stephen B. , Guo X. Edward , Rodeo Scott A. , Lu Helen H.
Published: April 2008

Achieving functional graft integration with subchondral bone poses a significant challenge for orthopaedic soft tissue repair and reconstruction. Soft tissues such as the anterior cruciate ligament (ACL) integrate with bone through a fibrocartilage interface, which minimizes stress concentrations and mediates load transfer between soft and hard tissues. We propose that biological fixation can be achieved by regenerating this fibrocartilage interface on biological or synthetic ACL grafts. This study focuses on the in vivo evaluation of a stratified scaffold predesigned to mimic the multitissue transition found at the ACL‐to‐bone interface. Specifically, the scaffold consists of three distinct yet continuous phases: Phase A for ligament formation, Phase B for the interface, and Phase C for the bone region. Interface‐relevant cell types, specifically fibroblasts, chondrocytes, and osteoblasts, will be tri‐cultured on this scaffold, and the formation of cell type‐ and phase‐specific matrix heterogeneity as well as fibrocartilage formation will be evaluated over 8 weeks in a subcutaneous athymic rat model. Acellular scaffolds as well as scaffolds co‐cultured with fibroblasts and osteoblasts will serve as controls. It was found that the triphasic scaffold supported multilineage cellular interactions as well as tissue infiltration and abundant matrix production in vivo. In addition, controlled phase‐specific matrix heterogeneity was induced on the scaffold, with distinct mineral and fibrocartilage‐like tissue regions formed in the tri‐cultured group. Cell seeding had a positive effect on both host infiltration and matrix elaboration, which also translated into increased mechanical properties in the seeded groups compared to the acellular controls. In summary, the biomimetic and multiphasic design coupled with spatial control of cell distribution enables multitissue regeneration on the stratified scaffold, and demonstrates the potential for regenerating the interface between soft tissue grafts and bone. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008