bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the use of primary reference grade polydimethylsiloxane
Authors: Schmidt John A. , von Recum Andreas F. 
Published: May 2005

AbstractThere has been an increase in the use of primary reference material as a standard for identifying the cellular response to biomaterials. One such material is NHLBI–DTB polydimethylsiloxane (PDMS). The PDMS was developed for blood contacting studies and is composed of PDMS backed on one side with mylar. The results of implantation studies of two different publications are discussed in light of the different materials and different surface topographies of each of the materials. The appropriateness of in vivo studies using this reference material is questioned. © 1993 John Wiley & Sons, Inc.
A study of the geometrical and mechanical properties of a self‐expanding metallic stent—theory and experiment
Authors: Jedwab Michael R. , Clerc Claude O. 
Published: May 2005

AbstractStents are tubular devices that are used in cylindrical passages of the body following trauma or disease in order to keep the cross section of these passages open. A mathematical model of a self‐expanding metallic stent has been developed with the aim of predicting various geometrical and mechanical properties of the stent. The model was developed with the main assumptions that the stent acts as a combination of a number of independent open‐coiled helical springs with ends fixed against rotation, and that the springs undergo elastic deformations only. A series of experiments has been carried out in order to assess the validity of the model. The experimental results show good agreement with theory for the tests involving stent diameter and longitudinal force as a function of stent length and fair agreement, limited by frictional effects, for the tests involving radial pressure as a function of stent diameter. © 1993 John Wiley & Sons, Inc.
Biomechanical performance of new vascular sutures and needles for use in polytetrafluoroethylene grafts
Authors: Towler Michael A. , Tribble Curtis G. , Pavlovich Lucas J. , Milam James T. , Morgan Raymond F. , Edlich Richard F. 
Published: May 2005

AbstractTwo new cardiovascular monofilament sutures attached to taper point needles have been developed for use in expanded polytetrafluoroethylene (PTFE) grafts. One monofilament suture made of PTFE has a microporous structure that allows it to be channel swaged to a needle that closely approximates its suture diameter. The other suture is a monofilament polypropylene suture that has been extruded to produce a tapered swage end, which was significantly smaller than that of the remainder of the suture in order to be channel swaged to smaller diameter needles. On the basis of comprehensive biomechanical performances, the performance of the new needle suture products with needle/suture diameter ratios approaching 1:1 was superior to needle suture products with 2:1 needle/suture diameter ratios for use in PTFE vascular grafts, regardless of the suture material. © 1993 John Wiley & Sons, Inc.
A new bioactive bone cement consisting of BIS‐GMA resin and bioactive glass powder
Authors: Kawanabe Keiichi , Tamura Jiro , Yamamuro Takao , Nakamura Takashi , Kokubo Tadashi , Yoshihara Satoru 
Published: May 2005

AbstractWe have developed a bioactive bone cement consisting of silane‐treated CaOSiO2P2O5CaF2 glass powder as the filling particles and bisphenol‐a‐glycidyl methacrylate (BIS‐GMA) diluted with triethylene‐glycol dimethacrylate (TEGDMA) as the organic matrix. Histological examination demonstrated direct bonding between the cement and bone along the circumference of the cement at 4 weeks after implantation in rat tibia. The compressive strength and toughness of the cement were two and four times greater than those of polymethylmethacrylate (PMMA) cement, respectively. The inflammatory reaction of the skin caused by the new cement was not as intense as that for PMMA 3 days after subcutaneous implantation. This new cement may be applicable as a bioactive bone cement with high mechanical strength. © 1993 John Wiley & Sons, Inc.
A bibliography of monographic works on biomaterials and biocompatibility
Authors: Bush Renee B. 
Published: May 2005

AbstractOrganizing and accessing biomaterials‐related information is problematic because of the interdisciplinary nature of the field. Relevant information appears in the literature of numerous science and technology subdisciplines and there is no one index or database that covers all of the related publications. An additional barrier to information retrieval is the lack of a thesaurus for the field. Multiple terms representing the same concepts are currently employed and it is not always readily apparent which terms to use in a literature search. As an aid for students and researchers in the discipline, the author provides an indexed bibliography of English language monographic works on biomaterials and biocompatibility published after 1973. © 1993 John Wiley & Sons, Inc.
Strategy for in vitro evaluation of the interactions between biomaterials and complement system
Authors: Labarre Denis , Montdargent Béatrice , Carreno Marie‐Paule , Maillet Françoise 
Published: May 2005

AbstractBecause of the importance of complement activation in the induced activation of leukocytes in vivo, determination of complement‐activating capacity of a candidate biomaterial is an important step in evaluating its biocompatibility. In vitro evaluation can be performed in the presence of human serum by means of techniques described in the literature and reviewed in this paper. Certain physical and chemical parameters involved in complement activation by materials have to be assessed: the chemical composition of the surface, surface area in contact with serum, temperature and duration of contact, and ionic environment with emphasis on divalent ions. Concerning materials evaluation, the adsorption of complement proteins or protein fragments has to be determined in addition to activation. Following screening tests using CH50 determination, activation of both classical and alternative pathways leading to formation of C3 convertases and formation of C5 convertase should be assessed. An example of the determination of the complement‐activating capacity of two hydroxylated materials is presented and guidelines for in vitro evaluation are proposed. © 1993 John Wiley & Sons, Inc.
Assessment of olefin‐based IUD tail strings
Authors: Roylance David 
Published: May 2005

AbstractThe „tail string”︁ that extends from a contraceptive intrauterine device (IUD) into the vagina is an illustrative case in materials engineering design. The strings must satisfy certain criteria for strength and other properties in order to fulfill the function of providing a means of insuring that the IUD has not been ejected, and eventually of helping remove the IUD. This must be done without contributing to an additional risk of unwanted medical side effects beyond those that may be inherent in any such device. Oriented monofilament olefins appear to satisfy these criteria, and have been used successfully in several IUD designs. This article describes a study of two such monofilaments taken from new IUDs, showing how the material's processing, structure, and properties lead to effective performance as tail strings. Several types of used IUDs were also studied, to insure that nothing occurred during use that would alter the conclusions drawn from the study of new strings. © 1993 John Wiley & Sons, Inc.
Histological response to cylinders of a low modulus titanium alloy (Ti‐13Nb‐13Zr) and a wear resistant zirconium alloy (Zr‐2.5Nb) implanted in the rabbit tibia
Authors: Goodman S. B. , Davidson J. A. , Fornasier V. L. , Mishra A. K. 
Published: May 2005

AbstractTo assess new and existing materials for total joint arthroplasty, the authors performed a comprehensive histomorphologic and morphometric analysis of bone to cylinders implanted transversely in the proximal tibia of mature New Zealand white rabbits. Four sterile, cylindrical implants measuring 6.1 × 3.8mm were manually inserted through drill holes in both tibiae with a „line‐to‐line fit.”︁ The materials tested included: ASTM F‐75 cast cobalt‐chrome‐molybdenum alloy, commercially pure titanium wrought zirconium‐2.5 niobium alloy, zirconium oxide coated zirconium‐2.5 niobium alloy, wrought titanium‐13 niobium‐13 zirconium alloy, and nitrogen diffusion hardened titanium‐6 aluminum‐4 vanadium alloy. Control animals with or without drill holes were included. The animals were killed by barbiturate overdose 6 months postoperatively. The upper tibiae were harvested and processed for undecalcified histologic sections that were stained with toluidine blue. The sections were examined by an investigator blind to the identity of the implanted materials. A full necropsy was also performed.A collar of lamellar bone, of variable length and thickness, continuous with the original cortex formed a buttress around the implants. There was no evidence of foreign body or inflammatory reaction. The marrow was slightly fatty, but cells of allthree hematopoietic lines were identifiable. The materials investigated had the following ranking in decreasing order of bone contact: Ti‐13Nb‐13Zr > nitrogen hardened Ti‐6Al‐4V > C.P. titanium > Zr 2.5Nb >ZrO2 coated Zr‐2.5Nb > cast CoCr alloy. The difference between the groups was statistically significant (p = 0.05). For the variable „average bone layer thickness”︁ the ranking in decreasing order was: nitrogen hardened Ti‐6Al‐4V alloy = C.P. titanium > Ti‐13Nb‐13Zr > ZrO2/Zr‐2.5Nb > Zr‐2.5Nb > cast CoCr alloy (p = 0.19). For the variable „average bone layer thickness in bone contact regions,”︁ the ranking of the values, in decreasing order were: nitrogen hardened Ti‐6Al‐4V > C.P. titanium > ZrO2 coated Zr‐2.5Nb > Ti‐13Nb‐13Zr >Zr‐2.5 Nb > cast CoCr alloy (p = 0.02). The final necropsy reports of the animals identified no adverse findings that were concentrated to any particular implant group. The new, lower modulus materials Ti‐13Nb‐13Zr and Zr‐2.5 Nb, and nitrogen hardened Ti‐6Al‐4V appear to have a similar or superior bone response to CoCr alloy when implanted in the rabbit tibia model. © 1993 John Wiley & Sons, Inc.
Evaluation of absorbable poly(ortho esters) for use in surgical implants
Authors: Daniels A. U. , Andriano Kirk P. , Smutz W. Paul , Chang Melissa K. O. , Heller Jorge 
Published: May 2005

AbstractRecent reports describe an unfavorable noninfective inflammatory response to acidic degradation products in clinical applications of bone fixation devices fabricated from bulk hydrolyzing polyglycolides and polylactides (PGA and PLA). The work described here suggests that poly(ortho esters) (POEs) offer an alternative. By comparison, hydrophobic POEs degrade predominately via surface hydrolysis, yielding first a combination of nonacidic degradation products, followed by alcoholic and acidic products gradually over time. POE specimens proved acutely nontoxic in United States Pharmacopeia tests of cellular, intracutaneous, systemic, and intramuscular implant toxicity.Hot‐molded specimens degraded slowly in saline, retaining 92% initial stiffness (1.6 GPa flexion) and retaining 80% initial strength (66 MPa flexion) in 12 weeks. Degradation was almost unaffected by decreasing saline pH from 7.4 to 5.0. This demonstrated the relative hydrophobicity of POEs, since incorporation of small amounts of acid within the polymer markedly increases the degradation rate. Degradation rates were increased substantially by dynamic mechanical loading in saline. This may be true for other degradable polymers also, but no data could be found in the literature. Presumably, tensile loading opens microcracks, allowing water to enter.Solvent cast POE films were strong in tension (30 + MPa tensile yield) and reasonably tough (12–15% elongation to yield). Higher molecular weight films (41–67 kDa) showed no degradation in mechanical properties after 31 days in physiological buffer at body temperature. A 27‐kDa film offered similar initial strength and stiffness but began showing mechanical degradation at 31 days. The films showed a decrease in weight with exposure time but no change in either molecular weight or water absorption at 31 days, further supporting the observation that POE degrades by surface hydrolysis rather than by bulk hydrolysis. © 1994 John Wiley & Sons, Inc.
Materials and design concepts for an intervertebral disc spacer. I. Fiber‐reinforced composite design
Authors: Langrana Noshir A. , Parsons John R. , Lee Casey K. , Vuono‐Hawkins Monica , Yang Sai Wei , Alexander Harold 
Published: May 2005

AbstractThe intervertebral disc is a complex joint anatomically and functionally. It may be displaced or damaged due to trauma or a disease process. To alleviate this condition, it may be necessary to remove the involved disc surgically and fuse the two adjacent vertebrae. Fusion is one option; however, replacing the damaged disc (or part thereof) with a suitable synthetic equivalent to allow near normal joint motion is more desirable. Unfortunately, the complex mechanical properties of the lumbar disc cannot be duplicated with homogeneous synthetic materials (polymers). To overcome this fundamental problem we have developed rational designs utilizing biocompatible thermoplastic elastomers of various stiffnesses (durometers) with and without fiber reinforcements. Our design consisted of three components analogous to the natural end plates, annulus, and nucleus. In this study only the fiber‐reinforced design is considered. The variables examined in the present study included orientation of the fiber layers, number of fiber layers, and order of the reinforcing layers. The results of mechanical testing of the fiber reinforced disc spacer indicate that a range of compressive and torsional properties can be achieved. The results further demonstrate that properly developed, this design results in properties similar to the natural disc. Designs developed provided adequate compression and compression torsion properties for a synthetic spine disc spacer. © 1994 John Wiley & Sons, Inc.
Stimulation of bone healing by transforming growth factor‐beta1 released from polymeric or ceramic implants
Authors: Gombotz Wayne R. , Pankey Susan C. , Bouchard Lisa S. , Phan Duke H. , Puolakkainen Pauli A. 
Published: May 2005

AbstractThe ability of transforming growth factor‐beta1 (TGF‐β1) to stimulate bone healing was evaluated in a rat critical calvarial defect model. Both a low dose and a high dose of TGF‐β1 were incorporated into two different types of implants: one made from a composite of poly(lactic‐co‐glycolic acid) (PLPG) (50:50) and demineralized bone matrix (DBM), and the other from calcium sulfate (CaSO4). Scanning electron microscopy showed that the CaSO4 implants were more porous than the PLPG/DBM samples. Both types of implants released biologically active TGF‐β1 for over 300 h in vitro. The samples were implanted in a 9‐mm diameter rat calvarial defect for 6 weeks along with contralateral control implants containing no TGF‐β1. Microradiography and histological analysis were used to assess the bone healing in the defects. Microradiography revealed that the greatest amount of calcified bone (67.5%) was present in the CaSO4 implants containing a high dose of TGF‐β1 while minimal new bone formation occurred in the PLPG/DBM implants. Histologically, the PLPG/DBM implants exhibited an inflammatory response with little mineralization or bone formation. The defects containing the PLPG/DBM implants consisted of a connective tissue stroma with large void spaces. Giant cells and numerous polymorphonuclear leukocytes were present throughout the implants. In contrast, the CaSO4 implants had only a few inflammatory cells and the presence of mineralization and true bone was a more consistent feature. These preliminary studies show that TGF‐β1 is capable of inducing new bone formation. Furthermore, the materials used to deliver the growth factor can play a significant role in the bone healing process. © 1994 John Wiley & Sons, Inc.
Characterization of a polyepoxy compound fixed porcine heart valve bioprosthesis
Authors: Shen Shih‐Hwa , Sung Hsing W. , Tu Roger , Hata Cary , Lin David , Noishiki Yasuharu , Quijano Rodolfo C. 
Published: May 2005

AbstractConcerns with the currently available bioprostheses are calcification, long‐term durability, and suboptimal hemodynamic performance. It is well known that these concerns are all more or less related to the cross‐linking reagent, glutaraldehyde or formaldehyde, used in fixing bioprostheses. To address these concerns, we undertook the development of a porcine bioprosthesis fixed with a polyepoxy compound. In the development of this polyepoxy compound valve, it was found that the porcine leaflets fixed with polyepoxy compound were softer and more pliable than those fixed with glutaraldehyde. In this study, a special microtoming technique was developed to section the biological tissue so that the fixation uniformity in distinct layers of porcine aortic wall could be characterized. The fixation index and the denaturation temperature measurements in distinct layers of aortic walls showed that the cross‐linking density was uniform throughout the entire aortic wall for the polyepoxy compound fixed porcine valve. It was also noticed that the fixation index of the polyepoxy compound fixed aortic wall (91.5 ± 0.5, n =3) was not significantly different from that of its valvular leaflet (90.6 ± 0.8, n = 3). Similarly, the denaturation temperature of the polyepoxy compound fixed aortic wall (80.4 ± 0.9°C, n = 5) was statistically comparable to that of its valvular leaflet (79.0 ± 0.5°C, n = 5). The results of this study indicated that polyepoxy compound can adequately fix the entire porcine aortic wall as well as its valvular leaflets. In a preliminary study, three polyepoxy compound fixed valves were evaluated in the mitral position in a juvenile sheep model. At 5‐month retrieval, no calcification could be visually observed in any of the explanted valves. © 1994 John Wiley & Sons, Inc.
Fatigue behavior of a titanium femoral hip prosthesis with proximal sleeve‐stem modularity
Authors: Krygier Jan Janusz , Dujovne Ariel Ricardo , Bobyn John Dennis 
Published: May 2005

AbstractModular hip prostheses are increasing in variety and utilization. Component stability, high endurance limit, and minimal particulate debris generation are critical for long‐term clinical success. The purpose of this study was to characterize the fatigue response and evaluate the in vitro potential for component motion and wear of the S‐ROMTM, a Ti‐6Al‐4V hip prosthesis with a modular design based on a Morse taper connection. A fatigue jig was desiged to simulate fixation of the device at the sleeve‐bone interface only with distal support mainly against the lateral endosteal cortex. Two series of tests were performed in air at room temperature: one with direct vertical loading (to produce high bending moments in the coronal plane) and one with a compound loading angle directed at 15° out‐of‐plane (to include torsional physiological loads). Applied loads using a servohydraulic test machine ranged from 5 × BW (body weight) to 9 × BW (1 × BW = 73 kg, ≈ 160 lb) at 10 Hz on an Instron apparatus. No mechanical failures were observed on the 11‐mm size stems below 6 × BW for in‐plane vertical loading, and at or below 7 × BW for out‐of‐plane loading. Using displacement monitoring with a sensitivity of 35 μm, no measurable slippage or relative motion was detected between the stem and sleeve when they were properly assembled. Examination of the contact areas with scanning electron microscopy revealed random surface modification (an indication of fretting or burnishing) with occasional evidence of transfer of material between stem and sleeve. At loads under 7 × BW there was no visual evidence of loose wear debris in the presence of gross stability. Overall, the extent of surface change or wear was relatively small in all components tested at physiological load levels. © 1994 John Wiley & Sons, Inc.
Evaluation of a new absorbable lactomer® subcuticular staple
Authors: Zachmann Gregory C. , Foresman Pamela A. , Bill Timothy J. , Bentrem David J. , Rodeheaver George T. , Edlich Richard F. 
Published: May 2005

AbstractThe most recent advance in skin stapling is the Auto Suture® SQS®‐20 disposable stapler. It approximates and everts wound edges, placing one synthetic absorbable pin in the dermis each time the instrument handle is activated. Staple wound closure was accomplished four times faster than sutural closure of the dermis. Wounds with staple pin closure exhibit superior resistance to infection than wounds approximated by dermal sutures. Although sutures provide more immediate wound security, as measured by wound breaking strength, than dermal pins, the breaking strength of wounds subjected to either dermal pins or dermal sutures were not significantly different 14 days after wounding. © 1994 John Wiley & Sons, Inc.
Biomechanical aspects on rehydrated freeze‐dried human allograft dura mater tissues
Authors: Wolfinbarger Lloyd , Zhang Yongxing , Adam Bao‐Ling T. , Homsi Diana , Gates Kevin , Sutherland Vicki 
Published: May 2005

AbstractBiomechanical properties of rehydrated freeze‐dried human dura mater tissues were studied. Scanning electron and polarized light analysis indicated a multilayered distribution of collagen fibers in the dura mater tissue. Uniaxial tensile testing of 95 test strips permitted determination of average values for failure stress (6.65 ± 0.14 MPa), failure strain (0.15 ± 0.003), tangent modulus (69.50 ± 1.29 MPa), elongation (0.56 ± 0.01), and tangent stiffness (12.53 ± 0.24 kN/m) of the dura mater tissue. © 1994 John Wiley & Sons, Inc.
A new saw technique improves preparation of bone sections for light and electron microscopy
Authors: Klein C. P. A. T. , Sauren Y. M. H. F. , Modderman W. E. , van der Waerden J. P. C. M. 
Published: May 2005

AbstractA newly developed saw technique was developed to produce sections circa 10 μm or thicker from fresh bone or dentine and from plastic embedded undecalcified bone tissue with or without implant materials. The method comprises only one step because grinding or polishing to make the sections thinner is not necessary. The bone slices can be decalcified rapidly without using aggressive solvents and used for making ultrathin sections for electron microscopy. Sections of fresh dentine of 15 to 30 μm are transparent which makes it possible to study osteoclastic resorption in vitro. Sections, 10 μm thick, with an intact interface of bone and implant material can be observed for biocompatibility studies. © 1994 John Wiley & Sons, Inc.