bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential expression of transforming growth factor‐α and macrophage colony‐stimulating factor/colony‐stimulating factor‐1R (c‐fms) by multinucleated giant cells involved in pathological bone resorption at the site of orthopaedic implants
Authors: Al‐Saffar Najat , Revell Peter A. 
Published: February 2005

AbstractThe immunologic response to prosthetic biomaterial particles is characterized by macrophage‐rich inflammatory infiltrate, formation of multinucleated giant cells, and aseptic loosening at the site of arthro‐plasty. We investigated the in vivo expression and tissue distribution of transforming growth factor alpha, macrophage colony‐stimulating factor, and the receptor for colony‐stimulating factor‐1 at the site of bone erosion in patients with clinically failed orthopaedic implants (n = 30). The expression was further compared with that detected in the inflamed synovial membranes from patients with rheumatoid arthritis or osteoarthritis (n = 15) and one patient with osteoclastoma (giant cell tumour of bone). Immunostaining of the tissue demonstrated positivity for transforming growth factor alpha within the inflammatory macrophage and multinucleated giant cell infiltrate in the diseased synovial membrane and the bone‐implant interface. A comparative analysis between the synovium and retrieval interface membranes (pseudosynovium) revealed a high level of expression of transforming growth factor alpha, with intense membrane staining on multinucleated giant cells in all failed arthroplasties with pseudosynovium. In addition, the frequency, antigenic phenotype, and pattern of transforming growth factor alpha expression on multinucleated giant cells in the interface were markedly similar to those observed for multinucleated giant cells in osteoclastoma. Multinucleated giant cells within the interface lacked the expression of macrophage colony‐stimulating factor and colony‐stimulating factor‐1 receptor, whereas those at the bone surfaces exhibited strong immunoreactivity. The predominant expression of transforming growth factor alpha by multinucleated giant cells in the boneimplant interface and its similarity to osteoclastoma highlight the importance of assessing transforming growth factor alpha as a possible contributor to the development of bone‐resorbing giant cells at the site of failed orthopaedic implants.
Loosening of sacral screw fixation under in vitro fatigue loading
Authors: Lu William W. , Zhu Qingan , Holmes Andrew D. , Luk K. D. K. , Zhong Shizhen , Leong C. Y. 
Published: February 2005

AbstractSacral screw fixation is frequently used for fusion of the lower lumbar spine, but sacral screws appear to offer less secure fixation than lumbar pedicle screws, and failure due to loosening under fatigue loading is common. The aim of this study was to examine in vitro the stability of medial and lateral bicortical and unicortical sacral screw fixation under a physiologically relevant fatigue‐loading pattern. Bone mineral density, screw insertion torque, and screw‐fixation stiffness were measured prior to cyclic loading between 40 and 400 N compression at 2 Hz for 20,000 cycles. The screw‐fixation stiffness was measured every 500 cycles, and the axial pullout strength of the screws was recorded following loading. All of the lateral insertions loosened under the applied loading, but some of the medial insertions remained stable. Medial insertions proved stiffer and stronger than lateral insertions, and bicortical fixations were stronger than unicortical fixations. Bone mineral density and insertion torque were correlated with screw stiffness and pullout strength, although better correlation was found for insertion torque than bone mineral density. Bone mineral density is a good preoperative indicator of sacral screw‐fixation strength, and insertion torque is a good intraoperative indicator. An insertion torque greater than 1.5 Nm is suggested as an indicative value for a stable medial unicortical insertion, whereas an insertion torque greater than 2 Nm suggests a stable medial bicortical insertion. It appears that, apart from the choice of technique (screw orientation and depth), minimizing the load on the screws during the initial part of the fusion process is also critical to maintain stability of the fused section and to obtain a solid fusion mass.
Is the circumferential tensile modulus within a human medial meniscus affected by the test sample location and cross‐sectional area?
Authors: Lechner Kate , Hull M. L. , Howell S. M. 
Published: February 2005

AbstractQuantifying the material properties of the human menisci is paramount to understanding their biomechanical functions within the knee. One important intrinsic material property governing the biomechanical functions of the meniscus is the circumferential tensile modulus. The purpose of this study was to determine if the circumferential tensile modulus of the human medial meniscus depends on the location and thickness of the sample tested. The following three hypotheses were tested: (a) the circumferential location (anterior, central, and posterior) does not significantly affect the tensile modulus, (b) the radial location (inner to outer) significantly affects the tensile modulus, and (c) the thicknes (cross‐sectional area) significantly affects the tensile modulus. Test samples, whose length was oriented in parallel with the circumferential collagen fibers, were collected from different circumferential and radial locations throughout 30 human medial menisci. Samples of three different thicknesses (0.5, 1.5, and 3.0 mm) were taken from three equal groups of 10 menisci (i.e., one thickness per group). The circumferential tensile modulus was measured under quasi‐statc loading. Statistical analysis showed no significant effect of the circumferential or radial location of the sample on the circumferential tensile modulus. This indicates that an overall circumferential tensile modulus may be calculated for the human medial meniscus by averaging the values determined at the various locations. However, the thickness of the test sample had a significant effect on the measured circumferential tensile modulus: the modulus varied inversely with the thickness. Thus, moduli determined from test samples that are too small in cross‐sectional area overestimate the effective modulus of the tissue on the whole, and the cross‐sectional area of the sample must be considered when determining a representative circumferential tensile modulus for the medial meniscus in a human knee.
Tendon‐defect and muscle‐unloaded models for relating a rotator cuff tear to glenohumeral stability
Authors: Hsu Horng‐Chaung , Boardman N. Douglas , Luo Zong‐Ping , An Kai‐Nan 
Published: February 2005

AbstractRotator cuff tear and glenohumeral instability are closely related. Any tear may disturb muscle force generation due to pain inhibition. In addition, a full‐thickness tear may foster instability by removing a structural element constraining the joint. It was hypothesized that the loss of both dynamic force and static constraint with a rotator cuff tear will affect glenohumeral stability. In a tendon‐defect model, dynamic and static elements of the joint were sacrificed. In a muscle‐unloaded model, only the dynamic element was removed. The location and size of the defect were also investigated. The effect on instability of a small tendon defect was less than that of muscle unloading, implying that a patient with a small tear would have less instability than a patient with weak or nonfunctioning supraspinatus and infraspinatus muscles. On the other hand, with a larger tear the defect had a greater effect than muscle‐unloading because sectioning of the glenohumeral and coracohumeral ligaments was included in the model. Clinically, such a defect in the front is critical for anterior stability because it might insult the important anterior capsule ligamentous complex. Orthopaedic surgeons should pay attention, therefore, to the effect of possible associated lesions of static constraints based on the size and location of the tear in addition to the dynamic stabilizer.
Cyclooxygenase‐2 inhibitor SC‐236 attenuates mechanical allodynia following nerve root injury in rats
Authors: DeLeo Joyce A. , Hashizume Hiroshi , Rutkowski Maria D. , Weinstein James N. 
Published: February 2005

AbstractLow back pain is a common problem, affecting approximately two‐thirds of the adult population. Of these individuals, a significant percentage will exhibit symptoms of radicular pain or sciatica. The purpose of this study was to determine the effect of one systemic (2 mg/kg) or intrathecal (0.2 mg/kg) dose of a selective cyclooxygenase‐2 inhibitor (SC‐236) in decreasing existing mechanical allodynia in a rat model of radiculopathy. Gait disturbance and mechanical allodynia (increased response to non‐noxious von Frey monofilament stimuli) were assessed daily until the rats were killed 7 days after surgery. Robust mechanical allodynia developed in the rats in all groups except for those in the sham group by day 1 after surgery. Mechanical allodynia was significantly lower in the rats that received the systemic or the intrathecal dose of SC‐236 than in those in the vehicle control group (analysis of variance followed by Bonferroni multiple comparison test, p = 0.002). The intrathecal drug route of administration produced greater attenuation in allodynia than the systemic dose, supporting a central mechanism of action of the cyclooxygenase‐2 inhibitor (p = 0.002). The hypothesis that cyclooxygenase‐2 is involved in spinal nociceptive processing after a nerve root injury was supported by this study. In addition, these data support continued basic science research to further elucidate central inflammatory processes that follow nerve root injury.
A chemist contemplates models of intermolecular collisions: A game of billiards or a demolition derby
Authors: Bauer S. H. 
Published: February 2005

AbstractThe kinetic molecular theory is one of the major triumphs of the physical sciences. In the following essay, we trace its current quantitative formulation, which was derived from concepts introduced during the early decades of the 19th century. Its evolution incorporated a sequence of refinements of models and of detailed mathematical analyses. Remarkably, it bridges measurable macroscopic properties and molecular parameters. However, for chemical kinetics applications it is incomplete, and its intrinsic conceptual simplifications should not be overlooked when using the theoretically derived relations. Consideration should be given to limits of applicability, and to be cognizant of features that are not fully compatible with other molecular models that are derived from diverse sources. In some measure, quantum mechanical formulations of molecular encounters bypass some of the inadequacies of the classical treatment. Herein, the designation “molecular models” refers not only to the postulated shapes, sizes, and interaction potentials of the elementary particles but also to the underlying mathematical analyses that lead to relations between observable quantities. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 191–200, 2005
Complex Adhesion Effects of Inorganic Nanofillers vs Microfillers in Polymer Composites
Authors: Kovačević V. , Leskovac M. , Lučić Blagojević S. 
Published: February 2005

AbstractThe adhesion parameters of fillers in composites, coefficient of wetting, interfacial free energy and work of adhesion, were calculated in order to evaluate the difference between the effects of selected microfillers vs nanofillers in polyacrylate (PA) and poly (vinyl acetate)(PVAc) matrix. The results showed that the improved fundamental adhesion, i.e. higher work of adhesion in nanocomposites resulted in the improved practical adhesion i.e. higher mechanical properties. The interfacial region was additionally modified by the controlled pre‐treatment of calcium carbonate micro‐ and nanofillers by sodium stearate that lowered the interactions with PVAc matrix. The composite morphological and mechanical properties changed accordingly. The lowered coefficient of interactions explained the pronounced composite failure at the interphase by dewetting and finally lead to the composite weakening. The conclusion about the complex relationship between the composite properties and engineering the interphase was confirmed.
Influence of the Particle Size of CaCO3 on the Adhesion of Filled EVA Materials
Authors: Martínez‐García Asunción , Sánchez‐Reche Ana , Cepeda‐Jiménez Carmen M. , Martín‐Martínez José Miguel 
Published: February 2005

AbstractA surface treatment with corona discharge was used to improve the adhesion properties of ethylene vinyl acetate copolymer (EVA) containing small amounts of four CaCO3 with different particle size. The nature of the surface modifications produced by the corona discharge treatment and the adhesion to a polychloroprene adhesive were assessed. Treatment of CaCO3 filled EVA with corona discharge produced a decrease in water contact angle value, irrelevant to the different particle size of the calcium carbonates. The corona discharge treatment created C‐O and C=O moieties on the EVA surface and also increased the peel strength, more markedly as the CaCO3 particle size increased. In general, a mixed (adhesion + cohesive in the EVA) failure in the filled EVA material was produced (assessed by IR‐ATR spectroscopy and SEM micrographs of the failed surfaces), but the failure was more cohesive in the EVA containing higher particle size CaCO3. The durability of the joints was also studied.
Polypropylene‐Clay Nanocomposites: Comparison of Different Layered Silicates
Authors: Leuteritz Andreas , Pospiech Doris , Kretzschmar Bernd , Willeke Meike , Jehnichen Dieter , Jentzsch Ulrike , Grundke Karina , Janke Andreas 
Published: February 2005

AbstractIn former studies of the preparation of polypropylene(PP)‐clay nanocomposites, different types of layered silicates were used. However, the obtained results were not comparable due to different preparation conditions and types of silicates. The aim of this work was the investigation of the influence of different layered silicates on the properties of the resulting nanocomposites. FT‐IR‐spectra, SAXS, TEM micrographs, elemental analysis, mechanical properties and surface tension measurements were used for the comparison of the four different layered silicates under investigation.
Reprocessable and Easy Processing Silica Filled Brominated Isobutylene para Methyl Styrene (BIMS)
Authors: Wong Wai Keung 
Published: February 2005

AbstractWithout the use of any curatives, silica filled BIMS compounds can achieve tensile strength and bound rubber level close to conventional crosslinked elastomer compounds. This outstanding tensile performance of silica filled BIMS compounds results from the strong interaction between BIMS polymer and silica filler. Silica filled BIMS compounds can be reprocessed and still retain their high tensile strength performance. The good compatibility between BIMS and silica also leads to better filler dispersion and inhibition of filler‐filler interaction. This in turn leads to the lower processing viscosity observed. We speculate that BIMS can interact with silica via nucleophilic substitution reaction between benzylic bromide of the polymer and surface silanol group of silica.
Use of Aminosilane Coupling Agents in Cementitious Materials
Authors: Švegl Franc , Šuput‐Strupi Jerneja 
Published: February 2005

AbstractThe work presented in this paper has been focused on the evaluation of the influence of the addition of aminosilanes like γ‐aminopropyl‐triethoxysilane (3‐AMPS) on physical and mechanical properties of fresh and hardened polymer modified cement mortars (PMCMs), which contained also mineral fillers like fumed silica and blast furnace slag. The role of the aminosilane in cementitious system was to produce surface modification and covalent bonding among different inorganic phases of inorganic matrix (cement, aggregate, fumed silica) and strong chemical interaction between inorganic matrix and organic (polymer) phase of the mortar. The strong chemical bonding of inorganic matrix and polymer phase transformed composite mortar into cementitious material with more like monolithic structure. Mortars with the addition of aminosilanes showed improved physical‐mechanical properties like bending strength, adhesion to concrete, and lower dry‐shrinkage.
An Electroconductive Filler for Shielding Plastics
Authors: Kandasubramanian B. , Gilbert M. 
Published: February 2005

AbstractA well characterised grade of mica was used to prepare nickel‐coated mica fillers by an electroless coating technique. These fillers were incorporated into polypropylene (PP) and acrylonitrile‐butadiene‐styrene (ABS) using a Haake Internal mixer and a two‐roll mill to produce conducting composites suitable for EMI shielding applications. Compounded polymers were fabricated into sheets of different thickness by compression moulding. The dependence of conductivity on sample thickness was studied and samples were tested for electrical resistivity, shielding efficiency, and thermal and mechanical properties. Reduced sample thickness during compression moulding decreased the electrical resistance of the polymer composites due to orientation and the formation of a good conducting network. Volume resistivity of PP composites was lower than for ABS composites with 50% Ni coating and equivalent filler weight fracions, showing that better conductivity could be achieved in a semi crystalline polymer than in an amorphous polymer. 0.6 weight fraction of 50 wt.% nickel coated mica in ABS showed a shielding efficiency of 16dB compared with 27.8dB in PP.
Models for the Investigation of the Structure of Vulcanizates
Authors: Magryta Jacek 
Published: February 2005

AbstractFor the investigation of vulcanizates structure, new models have been developed relating the modulus of vulcanizates and the volume fraction of filler. The parameters of the models are the filler distribution and the properties of the shell surrounding the filler particles. Three functions of filler distribution have been assumed. Dynamic mechanical properties of a series of vulcanizates were tested and the parameters of the models were computed. The obtained data allows estimating the properties of the shell formed around filler particles in vulcanizates and to distinguish the functions of filler distribution.
Multiple Threshold Percolation in Polymer/Filler Composites
Authors: McQueen Douglas H. , Jäger Karl‐Michael , Paligová Michaela 
Published: February 2005

AbstractLocal variations in filler particle concentration and/or shape and orientation in static filler/polymer composites are modelled as distributions of percolation thresholds. The concentration variations can be due to insufficient mixing, formation of semicrystalline voids during cooling from the melt, shrinkage during polymer curing, flow during physical compression or the like. Irregular filler shapes, especially elongated shapes, reduce the percolation threshold; thus natural variations in the shapes and orientations of filler particle aggregates lead to locally varying percolation thresholds. A distribution of percolation thresholds leads to an apparent percolation threshold based on the conductivity below the mean percolation threshold. For filler concentrations above the apparent percolation threshold the dielectric constant continues to increase before reaching a lowered peak value at the mean percolation threshold and then decreasing. Own experimental results on EBA /carbon black composites support the theory.
Effect of Silica Particle Size on Polymer Adsorption. Morphological, Energetic and Conformational Relationships
Authors: Al Akoum Rami , Haidar Bassel , Vidal Alain 
Published: February 2005

AbstractA series of six chemically treated and untreated fumed silicas with increasing particle size (ranging from the nano‐ to the micrometer size) was prepared. Surface areas (and morphologies) and surface energies were determined by nitrogen adsorption and inverse gas chromatography, respectively. The adsorption of a series of PDMS with different and well‐defined molecular weights was studied at different polymer concentrations. Amounts of adsorbed polymer were determined by gravimetry and the energies of adsorption were assessed by flow‐microcalorimetry. Results are discussed in terms of particle surface energy and morphology effects on the conformation and the inter‐connectivity of adsorbed polymer molecules.
Cortical cytoskeleton of giant moth eggs
Authors: Jarnot B. , Watson C. , Laffan E. , Nichols L. , Geysen J. , Berry S. J. 
Published: February 2005

AbstractUnfertilized eggs of several species of giant moths contain a substantial cortical cytoskeleton. This structure is assembled during oogenesis, and contains actin as a major fibrillar component. The presence of actin was confirmed by gel electrophoresis and binding to phalloidin, DNase 1, and a monoclonal antibody against cytoskeletal actin. Several lines of evidence suggest that the fat body is a source of the actin in the oocyte and that the transport and acquisition of actin by the ovary are similar to the mechanism of vitellogenin acquisition. A possible role for the cortical cytoskeleton in directing early embryogenesis is discussed.
Episomal replication of cloned DNA injected into the fertilised ovum of the hen, Gallus domesticus
Authors: Sang Helen , Perry M. M. 
Published: February 2005

AbstractWe describe preliminary experiments to analyse the fate of cloned DNA microinjected into the cytoplasm of the chick fertilised ovum. The reporter gene construct pRSVcat was injected into the germinal disc before the first cleavage divison, and the chick embryos were cultured for up to 7 days using the method of Perry (Nature 331:70–72, 1988). Linear plasmid molecules ligated rapidly after injection to form highmolecular‐weight DNA molecules consisting mainly of random concatemers of the injected plasmid. Recombination involving circular molecules resulted in head‐to‐tail multimers of the plasmid. Some of the DNA was lost after injection, but the remainder was replicated approximately 20‐fold during the first 24 h of development. Between days 1 and 7 in culture, the DNA was gradually lost and diluted out as the embryos developed. By day 7 in culture plasmid DNA was detectable in only 30% of the cultures analysed. No evidence for chromosomal integration of the exogenous DNA was obtained, suggesting that the plasmid DNA persisted episomally. Expression of the reporter gene construct pRSVcat was detected in day 2 and day 7 embryos.
Northern analyses using single‐stranded probes do not support a role for GATA/GACA repeats in sex determination in mice and men
Authors: Durbin Edward J. , Stalvey John R. D. , Erickson Robert P. 
Published: February 2005

AbstractThe possible role of GATA/GACA repeated sequences in mammalian sex determination was investigated using Northern analyses of mouse and human RNA. Brain, liver, and gonadal RNA from three developmental stages of mice of both sexes and also human fetal RNA from various tissues were hybridized to both sense and antisense Bkm riboprobes as well as to the synthetic oligonucleotide (GATA)5. At low levels of stringency, putative transcripts of various sizes were observed in all tissue samples with all probes. At high stringency, only a putative transcript of approximately 12 kb was observed, but this was later shown to consist of contaminating DNA. No sex‐specific differences were observed in any tissue or developmental stage. Thus, we find no evidence that the GATA/GACA repeated sequences are specifically expressed in quantities detectable by Northern analyses in a manner important to mammalian sex determination.