bluuebunny/crossref_metadata_2025 huggingface dataset:
Long‐term stability of a coronary stent coating post‐implantation
Authors: Lewis A. L. , Furze J. D. , Small S. , Robertson J. D. , Higgins B. J. , Taylor S. , Ricci D. R.
Published: November 2002

A coronary stent possessing a phosphorylcholine‐based polymer coating was removed from a human patient 6 months after implantation and analyzed for the presence of the coating. An atomic force microscopy (AFM) technique has been employed to scrape away several 10‐μm2 areas on the struts of the explanted stent. Scanning‐electron microscopy (SEM) and tapping‐mode AFM confirmed a surface coating had been removed in each case. Cross‐sectional analysis and force‐of‐removal measurements showed that both coating depth and hardness were characteristic of that for the phosphorylcholine‐ (PC‐) based coating prior to implantation. AFM amplitude‐phase and distance curves from the explanted stent were comparable to those obtained when an unused stent was analyzed. Furthermore, laser ablation high‐resolution inductively coupled‐plasma mass spectometery (LA‐HR‐ICP‐MS) was used to detect the low level of silicon present in the PC coating after explantation. The results from these techniques confirm that the stent coating is the original PC polymer and is not of biological origin, and support the long‐term stability of the coating in vivo. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 699–705, 2002
The long‐term behavior of poly‐L‐lactide screws in a minipig fracture model: Preliminary report
Authors: Hasegawa Yukiharu , Sakano Shinji , Iwase Toshiki , Warashina Hideki
Published: November 2002

The long‐term degradation tissue response to poly‐L‐lactide (PLLA) screw was investigated for a minipig tibia fracture. As a bone‐fracture model, three PLLA screws per animal were used to fix a tibia that had been subjected to a crank‐shaped osteotomy. A total of 12 nine‐month‐old male minipigs were used. In time period from 1 month to 3 years, clinical, radiographic, and pathological studies were conducted. On macroscopic examination, no clear granuloma or fistula formation was noted for 3 years. On microscopic examination, no osteoclasts or giant cells were detected around the screws during the 3 years postoperatively. A substantial degradation of PLLA screw was observed between 2 and 3 years. At 3 years only slight residual breakdown products were found in macrophages. On electric microscopic examination, numerous degraded polymers were seen in a small number of macrophages around the screws. In this model, fixation of tibia fractures using PLLA screws was not associated with any side effects, and was safe and useful for up to 3 years. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 679–685, 2002
Mechanical properties of coagulated albumin and failure mechanisms of liver repaired with the use of an argon‐beam coagulator with albumin
Authors: Moffitt T. P. , Baker D. A. , Kirkpatrick S. J. , Prahl S. A.
Published: November 2002

Hemostasis in the traumatized liver has been achieved by thermally denaturing topically applied albumin. In this article, the mechanical properties of liver and denatured albumin (solder) were measured, and the failure methods of liver repaired with albumin were identified. The ultimate tensile strength and Young's modulus were measured for healthy liver (N = 20) and thermally damaged liver (N = 20). The ultimate tensile strength and Young's modulus were measured for three concentrations of coagulated albumin (25, 38, and 53%) in a single layer and for two layers of denatured 38% albumin. Failure under tension of argon‐beam coagulator soldered liver on the parenchymal surface (N = 30) with 38% albumin in two layers had a 70% occurrence for tearing at a mean stress of 39 kPa and a 23% occurrence for shearing at a mean stress of 7 kPa. Liver repaired on the interior surface (N = 11) failed in tension by tearing (64%) at a mean stress of 34 kPa and by shearing (36%) at a mean stress of 6 kPa. Argon‐beam coagulator soldering with 38% albumin took 6 s/cm2 for two layers of solder and gave the best balance of usability, strength, and matching of mechanical properties with those of the liver. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 722–728, 2002
Knoop hardness depth profiles and compressive strength of selected dental composites polymerized with halogen and LED light curing technologies
Authors: Uhl Alexander , Mills Robin W. , Vowles Richard W. , Jandt Klaus D.
Published: November 2002

After the first light‐emitting diode (LED) light curing units (LCUs) became available commercially, a comparison of mechanical properties between materials polymerized with conventional halogen lamps and this new technology was required. This study, therefore, investigated the curing performance of two conventional commercial halogen LCUs (Translux CL, Spectrum800), a custom‐made LED LCU prototype, and one of the first commercially available LED LCUs (LUXoMAX). The Spectrum800 was adjusted to a similar irradiance to the custom‐made LED LCU prototype. Both technologies were compared by measuring compressive strength and Knoop hardness depth profiles for selected dental composites polymerized for 20 or 40 s. Four dental composites (Z100, Spectrum TPH, Solitaire2, and Definite) were used. Two of these composites (Solitaire2 and Definite) contain co‐initiators in addition to the standard photoinitiator camphorquinone. In general, the material hardness obtained with the LUXoMAX was statistically significantly (p < 0.05) lower at the depths of 0.1, 1.0, 1.9, and 3.1 mm, for all composites and curing times, than for the other three LCUs. The LED LCU prototype achieved, with one exception, up to a depth of 1.9 mm a material hardness for the composites Z100, Spectrum TPH and Solitaire2 that was not statistically significant different (p < 0.05) from the hardness obtained with the halogen LCUs. At a greater depth (3.1 mm), however, the LED LCU prototype showed statistically significantly lower hardness values than the halogen units. The compressive strength test showed at a 95% confidence level that similar compressive strengths were achieved with the LCUs LUXoMAX and Spectrum800, and the Translux and LED LCU prototype. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 729–738, 2002
Hydroxyapatite‐based composite for dental implants: An in vivo removal torque experiment
Authors: Kong Young‐Min , Kim Dong‐Hwan , Kim Hyoun‐Ee , Heo Seong‐Joo , Koak Jai‐Young
Published: November 2002

Screw‐shaped dental implants were fabricated from commercially pure Ti (c.p. Ti) and HA‐based composites. The HA‐based composites were fabricated by mixing HA with Al2O3‐coated ZrO2 powders. The mechanical properties of these composites were enhanced by a factor of 3. These were implanted into the rabbit tibiae and the removal torque to loosen the implants in vivo was measured in order to investigate the osteointegration. After a healing period of 6 weeks, the implants were retrieved with a torque gauge instrument. The HA‐based composite implants showed an almost 2‐times‐higher removal torque when compared to the Ti implants (ANOVA, p < 0.05), indicating excellent biocompatibility to bone. Thus, HA‐based composites had not only better mechanical properties but also similar bioactivity as HA itself. It is believed that a HA‐based composite is suitable for artificial dental implants. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 714–721, 2002
S/e‐PTFE episcleral buckling implants: An experimental and histopathologic study
Authors: Mortemousque B. , Leger F. , Velou S. , Graffan R. , Colin J. , Korobelnik J. F.
Published: November 2002

To investigate tissue changes induced by the implantation of a silicone band coated with expanded polytetrafluoroethylene (S/e‐PTFE) used as scleral buckling, an experimental and histopathological study was performed in rabbits. The right eyes of eight rabbits were implanted for 28–85 days with S/e‐PTFE. No complications were encountered in any of the eyes, so histopathological examinations could be performed. Encapsulations combined with numerous giant cells were found to be surrounding the implants in seven eyes, and deposits from the mineral salts of calcium were found in three eyes, forming granulomas possibly caused by irregularities of the implant surface. The porous structure allowed a peripheral colonization by fibrovascular tissue. Taking into account the histological results, the use of this material does not appear suitable. However, this inflammation was limited and did not merge on surrounding tissues. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 686–691, 2002
Effect of antibiotics on the properties of poly(methylmethacrylate)‐based bone cement
Authors: He Y. , Trotignon J. P. , Loty B. , Tcharkhtchi A. , Verdu J.
Published: November 2002

The goal of this study was to examine the relationship between gentamicin concentration in Palacos R bone cement (in the mass fraction range of 0–9.4%) and various properties of the cement. The results from the thermal, density, and static compression tests show that gentamicin favors the cement polymerization in its final steps, and forms a diphasic structure with the cement [poly(methylmethacrylate)] matrix. The static compression properties in the dry state are only slightly modified by the presence of the antibiotic. Concerning aging in water at 37 °C, two types of behavior can be distinguished: below a critical concentration, approximately 3–4%, the extraction of gentamicin by water is slow and there is only a slight change of static compression properties. In contrast, above this critical concentration, the gentamicin extraction is fast and almost complete after 48 weeks, and there is a considerable loss of static compression properties. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 800–806, 2002
In vivo release of vancomycin from biodegradable beads
Authors: Liu Shih‐Jung , Wen‐Neng Ueng Steve , Lin Song‐Shu , Chan Err‐Cheng
Published: November 2002

The current delivery system of antibiotics for the treatment of osteomyelitis uses polymethylmethacrylate (PMMA) beads as a local drug‐release agent. The nonbiodegradable nature of the PMMA, however, necessitates a second operation to remove the beads. This article explores the alternative of using biodegradable polymers as antibiotic beads for a long‐term drug release in vivo. To manufacture an antibiotic bead, lactide‐glycolide copolymers were mixed with vancomycin. The mixture was compressed and sintered at 55 °C to form beads 8 mm in diameter. An in vivo animal model was proposed to characterize the elution rate of antibiotic over a 55‐day period. Biodegradable beads released high concentrations of antibiotic (well above the breakpoint sensitivity concentration) in vivo for the period of time needed to treat bone infection; that is, 4–6 weeks. A bacterial inhibition test was also carried out to determine the relative activity of the released antibiotics. The diameter of the sample inhibition zone ranged from 8 to 18 mm, which is equivalent to 9.1 to 100% of relative activity. In addition, the antibiotic concentration of systemic blood was found to be very low. Antibiotic‐impregnated biodegradable beads may have a potential role in the prevention and management of surgical infections. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 807–813, 2002
Predictive modeling of the mechanical properties of particulate hydroxyapatite reinforced polymer composites
Authors: Balać Igor , Uskoković Petar S. , Aleksić Radoslav , Uskoković Dragan
Published: November 2002

The influence of particle geometry and volume fraction on the mechanical properties of a hydroxyapatite (HAp) particulate reinforced polymer (poly‐L‐lactide and collagen) matrix composite was investigated through finite‐element (FE) analysis. For cube‐shaped (near sharp and curved corners and edges) embedded particles, it was found that the maximum stress concentration factor (SCF) in the matrix decreases with an increase of the HAp particle volume fraction (PVF). The maximum stress concentration in the matrix material containing a spherical inclusion has low sensitivity to the PVF. The compressive Young's modulus was found to be slightly dependent on particle shape, but very sensitive to PVF. Calculated stiffness values from FE analysis were compared to the experimental results available in the literature and with predictions from the Halpin–Tsai model. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 793–799, 2002
Osseointegration on metallic implant surfaces: Effects of microgeometry and growth factor treatment
Authors: Frenkel Sally R. , Simon Jordan , Alexander Harold , Dennis Michael , Ricci John L.
Published: November 2002

Orthopedic implants often loosen due to the invasion of fibrous tissue. The aim of this study was to devise a novel implant surface that would speed healing adjacent to the surface, and create a stable interface for bone integration, by using a chemoattractant for bone precursor cells, and by controlling tissue migration at implant surfaces via specific surface microgeometry design. Experimental surfaces were tested in a canine implantable chamber that simulates the intramedullary bone response around total joint implants. Titanium and alloy surfaces were prepared with specific microgeometries, designed to optimize tissue attachment and control fibrous encapsulation. TGFβ, a mitogen and chemoattractant (Hunziker EB, Rosenberg LC. J Bone Joint Surg Am 1996;78:721–733) for osteoprogenitor cells, was used to recruit progenitor cells to the implant surface and to enhance their proliferation. Calcium sulfate hemihydrate (CS) was the delivery vehicle for TGFβ; CS resorbs rapidly and appears to be osteoconductive. Animals were sacrificed at 6 and 12 weeks postoperatively. Results indicated that TGFβ can be reliably released in an active form from a calcium sulfate carrier in vivo. The growth factor had a significant effect on bone ingrowth into implant channels at an early time period, although this effect was not seen with higher doses at later periods. Adjustment of dosage should render TGFβ more potent at later time periods. Calcium sulfate treatment without TGFβ resulted in a significant increase in bone ingrowth throughout the 12‐week time period studied. Bone response to the microgrooved surfaces was dramatic, causing greater ingrowth in 9 of the 12 experimental conditions. Microgrooves also enhanced the mechanical strength of CS‐coated specimens. The grooved surface was able to control the direction of ingrowth. This surface treatment may result in a clinically valuable implant design to induce rapid ingrowth and a strong bone‐implant interface, contributing to implant longevity. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 706–713, 2002
Light scattering and in vitro biocompatibility studies of poly (vinyl pyrrolidone) derivatives with amino‐acid‐dependent groups
Authors: Baritaki Stavroula , Tzanakakis George N. , Alifragis John , Zafiropoulos Alexis , Tashmukhamedov Ravshan I. , Tsatsakis Aristidis , Shtilman Mikhail I. , Rizos Apostolos K. , Krambovitis Elias
Published: November 2002

Two poly (vinyl pyrrolidone) (PVP) families with amino‐acid residues (glycine, β‐alanine, γ‐aminobutiric acid and ϵ‐aminocaproic acid) on the base of the co‐polymer N‐vinyl pyrrolidone and allyl‐glycidyl ether (VP‐AGE) and on the base of epoxidized PVP (EPVP) were synthesized. Static and dynamic light scattering measurements of these PVP derivatives in water showed that their structure/ behavior were similar to that of PVP. The bioreactivity was also similar to that of PVP. Further investigation of the immunoreactive properties of the derivatives in in vitro proliferation assays with fresh normal human peripheral blood lymphocytes and monocytes led to the determination of a costimulatory profile for each derivative in terms of polyclonal stimulation, specific antigen presentation, and immunoglobulin secretion. This profile allows the selection of an appropriate derivative as a carrier that would suit the immunoreactivity needs of the immobilized ligand. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 830–837, 2002
Immobilization of an oxalate‐degrading enzyme on silicone elastomer
Authors: Malpass Charley A. , Millsap Kevin W. , Sidhu Harmeet , Gower Laurie B.
Published: November 2002

Urinary biomaterials are compromised by device‐related urinary tract infections, bacterial biofilm formation, and biomineral encrustation. In the absence of urinary infection, calcium oxalate is the prevalent encrustation mineral formed. Considering this, a novel approach was taken in the study reported here, in that an oxalate‐degrading enzyme, oxalate oxidase (OXO), was immobilized on the surface of silicone elastomer (PDMS), a common urological biomaterial. It was hypothesized that the enzymatic action of OXO could lower urinary oxalate levels near the device surface, thereby preventing calcium oxalate crystal formation. The PDMS surface was functionalized with the use of radio‐frequency plasma discharge (RFPD) in the presence of water vapor, then coated with 3‐aminopropyltriethoxysilane (AMEO). The resulting aminated surface was covalently coupled with OXO via glutaraldehyde bioconjugation. The ability of the OXO‐coated PDMS to prevent calcium oxalate encrustation was evaluated with the use of a modified Robbins device (MRD) encrustation model. RFPD performed on PDMS resulted in an increase in the hydrophilicity of treated surfaces, as measured by contact angle. X‐ray photoelectron spectroscopy studies showed increases in elemental oxygen, after water‐vapor plasma, and in nitrogen after AMEO derivatization. The immobilized enzyme was shown to retain 47.5% of its specific enzymatic activity as compared to free enzyme. In vitro experiments for 6 days, with the use of a MRD, showed 53% less encrustation deposits on discs coated with OXO than control discs. The results from the current study suggest that PDMS‐immobilized oxalate‐degrading enzymes are active against calcium oxalate encrustation. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 822–829, 2002
An evaluation of the cytotoxic effects of orthodontic bonding adhesives upon a primary human oral gingival fibroblast culture and a permanent, human oral cancer‐cell line
Authors: Huang Tsui‐Hsien , Tsai Ching‐Yi , Chen Shiow‐Ling , Kao Chia‐Tze
Published: November 2002

The purpose of this investigation was to determine the cytotoxic effects of three different kinds of orthodontic adhesive on a human primary gingival fibroblast culture (GF) and a human oral cancer‐cell line (OC2). The adhesives comprised a self‐cure bonding resin, a light‐cure bonding resin, and a hybrid glass ionomer. Any differences between the cytotoxic potencies of eluates of the orthodontic materials on GF and OC2 cells were quantified colorimetrically (MTT test). The results are as follows: For the hybrid glass ionomer, the survival rate of GF cells exposed to the liquid component revealed a significant dose‐dependent decrease (p < 0.05). The liquid component and the mixed hybrid glass‐ionomer material reflected a significant dose‐dependent decrease (p < 0.05) in exposed OC2 cell survival. Associated with an increase in the cell exposure concentration of Resin A, Resin B, Paste A, Paste B, Resin A + B, Paste A + B and the set material of the self‐cure resin adhesive, was a significant decrease in survival rate for cultured GF and OC2 cells (p < 0.05). Associated with an increase in the concentration of the primer, paste, and mixed material of the light‐cure resin adhesive to which test cells were exposed, the survival rate reflected a decrease for GF cells (p < 0.05). The survival rate of cells exposed to light‐cure resin paste reflected no difference for OC2 cells. It is concluded that the liquid of the hybrid glass‐ionomer cement, Resin A and Resin B and Resin A + B of the self‐cure resin and the primer of the light‐cure resin are toxic agents to the GF and OC2 cell lines. Primary human gingival fibroblasts were found to be more sensitive than the tested human oral carcinoma cell line from most of the substances. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 814–821, 2002
Machinability of cast commercial titanium alloys
Authors: Watanabe I. , Kiyosue S. , Ohkubo C. , Aoki T. , Okabe T.
Published: November 2002

This study investigated the machinability of cast orthopedic titanium (metastable β) alloys for possible application to dentistry and compared the results with those of cast CP Ti, Ti‐6Al‐4V, and Ti‐6Al‐7Nb, which are currently used in dentistry. Machinability was determined as the amount of metal removed with the use of an electric handpiece and a SiC abrasive wheel turning at four different rotational wheel speeds. The ratios of the amount of metal removed and the wheel volume loss (machining ratio) were also evaluated. Based on these two criteria, the two α + β alloys tested generally exhibited better results for most of the wheel speeds compared to all the other metals tested. The machinability of the three β alloys employed was similar or worse, depending on the speed of the wheel, compared to CP Ti. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 760–764, 2002
Do multifilament alloplastic meshes increase the infection rate? Analysis of the polymeric surface, the bacteria adherence, and the in vivo consequences in a rat model
Authors: Klinge U. , Junge K. , Spellerberg B. , Piroth C. , Klosterhalfen B. , Schumpelick V.
Published: November 2002

Within the last decade hernia surgery has changed from suture repair to mesh repair. Biomaterials, and multifilaments in particular, are thought to increase the risk of infection. Therefore, the aim of this study was to study the influence of the presence of either a monofilament or a multifilament mesh material on the bacterial infection risk. The filament surface of a monofilament and a multifilament mesh were calculated on the basis of a theoretical model. The adherence of Staphylococcus aureus was measured in vitro by fluorescence analysis. Additionally, the two mesh materials (8‐mm platelets) were implanted subcutaneously in Sprague–Dawley rats with daily surveillance for clinical signs of infection. After 7 days the meshes were explanted for histological and microbiological analysis. Calculations of the mesh surface area revealed a higher level for the multifilament mesh. The extent of adherent bacteria corresponded to the estimated filament surface in vitro. In vivo, the implantation of meshes in the presence of 5 × 106
S. aureus did not show an increased infection rate in rats with either monofilament or multifilament material, compared to the control groups (mesh implantation without S. aureus contamination). However, after 7 days bacteria were still detectable in the majority of the implantation sites, and a clinically inapparent intensification of local inflammation and fibrosis was induced. The increased surface area of a multifilament meshes promotes the persistence of bacteria in the implant bed, though this alone is not sufficient to create a clinically apparent infection. This might explain the development of mesh‐related infections after a delay of several months or even years. In vivo, the adherence of bacteria to the implant material depends on the surface area, which favors the use of monofilament materials. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 765–771, 2002
Tissue reaction and biodegradation of implanted cross‐linked high amylose starch in rats
Authors: Désévaux Cyril , Dubreuil Pascal , Lenaerts Vincent , Girard Christiane
Published: November 2002

The biocompatibility and degradation characteristics of cross‐linked high amylose starch (Contramid®) were investigated in rats over 4 months. Contramid® pellets (3‐mm diameter and thickness) obtained by direct compression, were implanted subcutaneously and intramuscularly. On sequential time points, macroscopic observations of implantation sites were performed and tissue samples were removed, fixed, and histologically evaluated. No macroscopic inflammatory reaction was observed with Contramid®. Upon histologic examination, inflammatory reaction produced by Contramid® was moderate and restricted to implantation sites. The sequence of inflammatory events with Contramid® was similar regardless of implantation site. Degradation of Contramid® pellets was characterized by fragmentation with formation of fibrovascular septa and phagocytosis by macrophages. Finally Contramid® was mostly absorbed by the end of the 4‐month period and substituted by adipocytes. It has been demonstrated that Contramid® is a biocompatible and absorbable material. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 772–779, 2002
Effect of TEGDMA on the intracellular glutathione concentration of human gingival fibroblasts
Authors: Engelmann J. , Leyhausen G. , Leibfritz D. , Geurtsen W.
Published: November 2002

Previous studies revealed that primarily small and relatively hydrophilic comonomers, such as TEGDMA, leach out of resin‐based restorative materials into aqueous media. Subsequently, these compounds may cause detrimental reactions with intracellular metabolic systems. The present experiments attempted to elucidate the interactions of TEGDMA with the important intracellular reducing agent glutathione (GSH). The influence of various concentrations of TEGDMA (0.5–7.5 mM) on viability and intracellular GSH concentration of primary human gingival fibroblasts was determined by means of a fluorescence assay (monobromobimane) performed in microtiter plates. Cells were treated with TEDGMA between 2 and 24 h. The incubation of fibroblasts with TEGDMA even at subtoxic concentrations quickly decreased the intracellular glutathione level to 30–50% of controls within the first 2–6 hours. However, no simultaneous adverse effect on cell viability was found. Longer incubation periods up to 24 h caused a regulatory reincrease at TEGDMA concentrations ≤ 2.5 mM, whereas higher concentrations resulted in a continuous depletion of glutathione concentration concomitant with a significant decrease of cell viability. Because glutathione plays an important role in protection and detoxification processes as well in the regulation of cell death, the early and extensive depletion of the intracellular glutathione pool due to TEGDMA may significantly contribute to the cytotoxic potency of this compound. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 746–751, 2002
In vitro and in vivo degradation of bioabsorbable PLLA spinal fusion cages
Authors: van Dijk M. , Tunc D. C. , Smit T. H. , Higham P. , Burger E. H. , Wuisman P. I. J. M.
Published: November 2002

The in vitro and in vivo degradation of poly‐L‐lactic acid cages used as an adjunct to spinal arthrodesis was investigated. In the in vitro experiments cages were subjected to aging up to 73 weeks in phosphate‐buffered solution (pH 7.4) at 37 °C. Inherent viscosity, crystallinity, and mechanical strength were determined at different time points. In the in vivo study, the poly‐L‐lactic acid cages were packed with bone graft and implanted in the L3‐L4 spinal motion segment of 18 Dutch milk goats. At 12, 26, and 52 weeks, the motion segments were isolated and poly‐L‐lactic acid samples retrieved. On evaluation, the in vivo implanted cages showed an advanced decline in inherent viscosity compared to the cages subjected to in vitro degradation experiments. At 6 months of implantation, the geometrical shape and original height of 10 mm was maintained during 6 months of follow up. This finding fits well with the observation that mechanical strength was maintained for a period of 6 months in vitro. At 12 months, the poly‐L‐lactic acid cage had been disintegrated into multiple fragments with signs of absorption. Despite the high–load‐bearing conditions, the poly‐L‐lactic acid cage allowed interbody fusion to occur without collapse of the cage. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 752–759, 2002
Biaxial flex‐fatigue and viral penetration of natural rubber latex gloves before and after artificial aging
Authors: Schwerin Matthew R. , Walsh Donna L. , Coleman Richardson D. , Kisielewski Richard W. , Kotz Richard M. , Routson Licia B. , David Lytle C.
Published: November 2002

Barrier integrity of unaged and oven‐aged (at 70 °C) natural rubber latex examination gloves was assessed with a biaxial flex‐fatigue method where failure was detected electronically, and by live viral penetration testing performed according to a modified version of ASTM F1671‐97a. When no change in barrier properties was detected during flex testing, no virus passage was found after viral challenge. Conversely, when a change in the barrier properties was indicated by the electrical signal, virus passage was found in 74% of the specimens. Flex‐fatigue results indicated that unaged test specimens from powdered (PD) and powder‐free (PF) nonchlorinated gloves had significantly longer fatigue lives than powder‐free chlorinated (CL) gloves from the same manufacturer. Biaxial flexing of oven‐aged glove specimens showed a marginal increase in fatigue life for the PF gloves, but no increase for the PD gloves. The fatigue life of the CL gloves was observed to increase significantly after oven aging. However, this appears to be due to a design feature of the test apparatus, wherein peak volume displacement of the worked specimen is held constant. An aging‐induced change in the viscoelastic properties of the CL gloves—permanent deformation of the specimens early in the fatigue test—relieves the stress magnitude applied as the test progresses. Thus, permanent deformation acts as a confounding factor in measuring durability of latex gloves by fixed displacement flex‐fatigue. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 739–745, 2002
Lifetime prediction of CAD/CAM dental ceramics
Authors: Lohbauer Ulrich , Petschelt Anselm , Greil Peter
Published: November 2002

The dynamic fatigue method was used to obtain subcritical crack growth parameters n and A for a commercial feldspathic dental porcelain and for a lanthanum‐glass‐infiltrated alumina glass ceramic. Five stress rates dσ/dt ranging from 50 to 0.01 MPa s−1 were applied. The inert strength values were calculated with the use of Weibull statistics and maximum‐likelihood approaches for the Weibull parameter m. Strength–probability–time (SPT) diagrams were derived for both materials. The alumina glass composite showed a high fracture strength σ0 (442 MPa) at a failure probability of PF = 63.2% and a high resistance against subcritical crack growth (n = 36.5). The development of strength under fatigue conditions was calculated for exemplary 1 year. The strength of the alumina glass material dropped to 228 MPa within this period. This fact is due to a low content of infiltrated lanthanum glass phase in the composite material (25 wt%). In contrast, for the high‐silica‐glass‐containing porcelain a distinct decrease of strength σ0 from initial 133 to 47 MPa after 1 year was predicted. This, mainly because of a low crack growth resistance (n = 16.8) of the feldspathic porcelain. Much lower strength values were calculated, assuming a failure probability of PF = 5%. The decrease is mainly caused by the sensitivity of high–glass‐containing ceramics against water corrosion. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 780–785, 2002
Immobilization of natural macromolecules on poly‐L‐lactic acid membrane surface in order to improve its cytocompatibility
Authors: Ma Zuwei , Gao Changyou , Gong Yihong , Ji Jian , Shen Jiacong
Published: November 2002

With the use of a grafting–coating method, three kinds of natural macromolecules, that is, gelatin, collagen, or chitosan, were immobilized on poly‐L‐lactic acid (PLLA) membrane surfaces with the goal of improving of cellular interactions. Attenuated total reflectance infrared spectroscopy (ATR‐IR), x‐ray photoelectron spectroscopy (XPS) and surface morphology analysis using scanning electronic microscopy (SEM) confirmed that the natural macromolecule layers adhered tightly to the hydrophobic PLLA membrane surfaces. Chondrocyte culture showed that the modified PLLA membranes had higher cell attachment, higher cell proliferation rate, and higher cell activity than the control PLLA membrane. Moreover, the chondrocytes were more spread out on the modified PLLA membranes than on the control PLLA membranes. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 838–847, 2002
Wear of conventional and cross‐linked ultra‐high‐molecular‐weight polyethylene acetabular cups against polished and roughened CoCr femoral heads in a biaxial hip simulator
Authors: Saikko Vesa , Calonius Olof , Keränen Jaakko
Published: November 2002

The wear of acetabular cups made from conventional γ‐sterilized, and electron‐beam cross‐linked ultra‐high‐molecular‐weight polyethylene was studied with a biaxial hip wear simulator. The femoral heads were either polished or roughened so that they represented the type of roughening and the value of surface roughness (Ra = 0.14–0.18 μm) observed in the roughest explanted femoral heads. The lubricant was diluted calf serum, and the test length 3 million cycles. The mean wear rate and standard deviation of conventional polyethylene cups against polished and against roughened heads was 11.6 ± 0.07 and 64.4 ± 10.1 mg per 1 million cycles, respectively. The latter value closely corresponds to that measured from explanted Charnley prostheses. Against polished heads, cross‐linked polyethylene cups showed net weight gain, whereas against roughened heads, their mean wear rate was 2.4 ± 0.3 mg per 1 million cycles. The mean equivalent circle diameters of polyethylene wear particles produced in the above four categories were: conventional/roughened 0.32 μm, cross‐linked/roughened 0.29 μm, conventional/polished 0.28 μm, cross‐linked/polished 0.23 μm. The size ranges and shapes were close to those seen in particles isolated from tissue samples. In conclusion, the tests indicated that electron‐beam irradiation effectively reduces the harmful polyethylene wear particle production in total hip arthroplasty. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 848–853, 2002
The anticorrosion ability of titanium nitride (TiN) plating on an orthodontic metal bracket and its biocompatibility
Authors: Kao Chia‐Tze , Ding Shinn‐Jyh , Chen Yu‐Chih , Huang Tsui‐Hsien
Published: November 2002

Typically, an orthodontic metal bracket is made from stainless steel. It has been shown that such metal may corrode in an acid‐ and chloride‐rich environment. The purpose of the current study was to investigate a titanium nitride (TiN) ion‐plated stainless steel orthodontic bracket's anticorrosion properties and compare its biocompatibility with that of non‐TiN‐plated brackets. The stainless‐steel brackets studied here were tested in acidic artificial saliva. The plated metal bracket was produced by the titanium nitride (TiN) ion‐plating method. The TiN‐plating on the bracket surface was demonstrated to be successful by EDX analysis. The quantity of metallic‐ion release under test immersion solutions was analyzed by atomic absorption spectrophotometry. Both TiN‐ and non‐TiN‐plated brackets may release detectable ions into the test solution, including nickel, chromium, manganese, copper, and iron (ferric). The anticorrosion ability of the plated bracket was analyzed by means of inductively coupled plasma atomic emission spectroscopy. The results revealed that the TiN‐plated metal bracket did not increase the anticorrosion ability of the standard bracket. The biocompatibility of the TiN plating versus the standard bracket material resulting from bracket immersion in the test solution revealed no toxicity on U2OS cells using a methylthiazole tetrazolium (MTT) colorimetric assay. Clearly, the search for an improved technique for enhancing the anticorrosion ability of the normal metal orthodontic bracket should be continued. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 786–792, 2002
Optimal currency baskets and the third currency phenomenon: exchange rate policy in Southeast Asia
Authors: Bird Graham , Rajan Ramkishen
Published: November 2002

Recent financial crises seem to have led to the broad consensus that developing countries should steer clear of exchange rate regimes that lie anywhere between the two extremes or [corner solutions] of credibly fixed or flexible arrangements. But is this a reasonable position to adopt? Would developing countries be well advised to follow this policy recommendation? Should developing countries opt only for the corner solutions? Did the crisis‐hit South‐east Asian countries (Indonesia, Malaysia, Thialand and Philippines), make a mistake in effectively pegging to the US dollar rather than in pegging per se? Did pegging to the US dollar constitute a sub‐optimal peg? If it did, what would have been the optimum peg? This paper attempts to provide answers to the preceding questions. The paper also conjectures more broadly about monetary policy in developing countries. Copyright © 2002 John Wiley & Sons, Ltd.
Being, becoming and relationship: conceptual challenges of a child rights approach in development
Authors: White Sarah C.
Published: November 2002

This paper considers the distinctiveness of children as development subjects and the challenges this poses to default development ‘target group’ approaches. It focuses on two key issues: the embeddedness of children within key relationships, and the transformative nature of age‐based difference. Rather than viewing adults and children as two fixed categories, it argues that multiple relations amongst and between adults and children comprise aspects of both mutual interest and contradiction, and are always implicated in power. Offering practical tools as well as conceptual discussion to explore these, overall it advocates a person‐centred, rather than category‐centred, approach to both analysis and practice. Copyright © 2002 John Wiley & Sons, Ltd.
‘Poor children grow into poor adults’: harmful mechanisms or over‐deterministic theory?
Authors: Yaqub Shahin
Published: November 2002

Does childhood poverty lead to adult poverty? Evidence shows childhood is a sensitive period for developing cognition, physical vitality and personality. This is traceable to specific behavioural and biological mechanisms. However such science could easily drive over‐deter ministic views about how childhood affects later life. The paper therefore discusses how damage from childhood poverty can—at least sometimes and partially—be resisted or reversed, both during childhood and in adulthood. As people reach biological maturity, alterations to their developmental trajectories rely increasingly on alterations in behavioural relationships. Opportunities remain vital throughout life for sustained socioeconomic attainment. Copyright © 2002 John Wiley & Sons, Ltd.
Public spending for children: an empirical note
Authors: Mehrotra Santosh , Delamonica Enrique
Published: November 2002

It is often said that economic growth promotes poverty reduction, social development and child welfare, but it is rarely argued that this conditional relationship applies in reverse. Direct action to improve child health and education may be as strong as economic growth in reducing income‐poverty. Without specific policies to ensure access to basic social services (BSS) like basic health, primary education access to safe water—services which directly improve children's lives—economic growth seldom improves the quality of life of the whole population. Thus, it becomes crucial to measure and monitor the allocation of public spending to BSS. In this paper, based on research carried out by UNDP and UNICEF in more than 30 countries across Africa, Asia and Latin America, we summarise some findings of these studies. The figures vary among countries and through time, but public expenditure on BSS is, on average, between 12 and 14 per cent of government spending. Such low fiscal priority to these services partly accounts for the poor health and education outcomes. In many low‐income, highly indebted countries, the low level of spending is explained by the lack of fiscal space. Hence the need for debt cancellation at a faster pace than achieved through the HIPC Initiative so far. Data on the use of education and health services by different groups show inequities in the distribution of public spending. This inequity negatively affects overall outcomes.

We also look at the allocation of foreign assistance to BSS. ODA has been declining, as a proportion of the output of industrialised countries, since the early 1980s. Within this shrinking total, no DAC country's combined allocation for BSS exceeded 16.5 per cent of ODA. Hence also the need for rapid increases in ODA for basic services. Copyright © 2002 John Wiley & Sons, Ltd.
Poverty reduction strategy papers (PRSPs)—fulfilling their potential for children in poverty?
Authors: Marcus Rachel , Wilkinson John , Marshali Jenni
Published: November 2002

Poverty Reduction Strategy Papers (PRSPs) are currently at the centre of development assistance and planning in many countries and donor agencies. As such, they are potentially of enormous significance for children living in poverty. Based on a review of PRSP documents, authors' experiences and other evidence, the paper explores the main policies of economic growth and social sector investment laid out in PRSPs and some likely implications for children's lives and equitable development. It examines how far PRSPs recognize childhood poverty as a priority, and the strategies' often limited commitments to tackle it. The paper reflects on changes in policy planning, budgeting and review processes associated with PRSPs and examines their potential to contribute to effective poverty reduction. It concludes that, to date, changes in these processes are the most significant contribution of PRSPs; while the potential for more effective policy is strong, much work is required by all involved before they are a comprehensive or strategic approach to reducing childhood poverty or securing the wellbeing of future generations. Copyright © 2002 John Wiley & Sons, Ltd.
Old age, poverty and social investment
Authors: Barrientos Armando
Published: November 2002

The paper examines two commonly held views on the relationship existing between old age and poverty in developing countries: that poverty is less pronounced among the old; and that poverty reduction programmes focused on the old have lower social payoffs than programmes aimed at the young. The paper argues that standard measures underestimate old age poverty, and that the evaluation of poverty programmes needs to take account of the economic contribution of the old and of positive externalities in old age support. It concludes that the low priority given to old age support in developing countries needs to be reconsidered. Copyright © 2002 John Wiley & Sons, Ltd.
Age and empowerment amongst slum dwelling women in Hyderabad
Authors: Afshar Haleh , Alikhan Fatima
Published: November 2002

This paper seeks to offer an understanding of empowerment in terms of the experiences of a group of slum dwelling older women in Hyderabad. It is the contention of this paper that their experience does not reflect the negative view of ageing common among Western researchers to the effect that old age is necessarily debilitating and disempowering. Copyright © 2002 John Wiley & Sons, Ltd.
Nussbaum, capabilities and older people
Authors: Lloyd‐Sherlock Peter
Published: November 2002

This paper assesses the usefulness of Nussbaum's version of the capabilities approach for understanding the condition of older people in developing countries. It observes that ageing is a highly heterogeneous experience, but that policy debates take a polarized approach. The paper then summarizes key elements of Nussbaum's approach, relates these to older people, and identifies a key distinction between older people's internal capabilities and structural factors related to the environment they inhabit. The paper puts forward a new framework, which combines capabilities and life‐course perspectives. The policy implications of this framework are then explored. Copyright © 2002 John Wiley & Sons, Ltd.
International organizations, pension system reform and alternative agendas: Bringing older people back in?
Authors: Charlton Roger , McKinnon Roddy
Published: November 2002

This paper delineates key constraints on the formulation and implementation of old age support in developing countries (DCs), identifying specific institutional and organizational points of ‘blockage’. The paper argues that these institutional and procedural constraints collectively underpin the continuing marginalization of older people within dominant agendas and existing policy programmes, presenting reformers with knotty problems of policy formulation, policy sequencing and policy implementation. A more appropriate and constructive international advisory regime, formed on the principles of organisational, stakeholder and policy inclusiveness, is proposed and outlined. Copyright © 2002 John Wiley & Sons, Ltd.
Head development in the onychophoran Euperipatoides kanangrensis with particular reference to the central nervous system
Authors: Eriksson B. Joakim , Tait Noel N. , Budd Graham E.
Published: November 2002

The neuroectoderm of the Euperipatoides kanangrensis embryo becomes distinguishable during germ band formation when the antennal segment is evident externally. During later stages of development, the neuroectoderm proliferates extensively and, at the anterior part of the head, newly–formed neuron precursor cells occupy most of the volume. The antenna forms from the dorsolateral side of the anterior somite. The antenna has no neuroectoderm of its own at the onset of its formation, but instead, neurons migrate out to the appendage from the nearby region of the developing brain. When the antennal tract is formed it is positioned horizontally in the brain, in line with the antennal commissure. Only later, and coincidentally with the anterior repositioning of the antenna, is the tract's distal part bent anteriorly and positioned laterally. The eye starts to develop posteriorly to the antenna and the antennal commissure. This suggests that the segment(s) associated with the onychophoran eye and antenna are not serially homologous with segments carrying equivalent structures within the Euarthropoda. Evidence is presented to further support the presence of a terminal mouth in the ground plan of the Onychophora and, hence, an acron may not exist in the arthropod clade. J. Morphol. 255:1–23, 2003. © 2002 Wiley‐Liss, Inc.