bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrolytic deposition of calcium phosphate/chitosan coating on titanium alloy: Growth kinetics and influence of current density, acetic acid, and chitosan
Authors: Wang Jiawei , van Apeldoorn Aart , de Groot Klaas 
Published: November 2005

AbstractElectrolytically deposited calcium phosphate/chitosan coating demonstrated good bone marrow stromal cell attachment. The aim of this study was to understand the coating's growth kinetics as well as the effects of current density, acetic acid, and chitosan on the coating's formation. The scanning electron micrographs found that calcium phosphate crystals homogeneously distributed into chitosan aggregates as early as 30 min. X‐ray diffraction patterns and Fourier transform infrared spectra demonstrated that the coating experienced a compositional conversion from octacalcium phosphate to carbonate apatite during the deposition process. Electric current influenced the deposition. Higher current density accelerated the process and induced faster and more chitosan deposition. Both acetic acid and chitosan were found to inhibit calcium phosphate deposition. Chitosan was thought to induce stronger effects than acetic acid did. Furthermore, the inhibitive effect related to their concentration in the electrolyte. When chitosan concentration increased to a certain degree, this inhibitive effect not only affected calcium phosphate deposition, but also affected its own deposition. The chitosan content within the hybrid coating was small, which could be verified through Raman spectrum. At the same time, no clear evidence of chemical reactions could be found between these two components. We considered that both components were just naturally wrapped to form as a whole. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Adsorption of charged albumin subdomains on a graphite surface
Authors: Raffaini Giuseppina , Ganazzoli Fabio 
Published: November 2005

AbstractWe report some new molecular dynamics simulation results about the adsorption on a hydrophobic graphite surface of two albumin subdomains, each formed by three different α‐helices, considering the correctly charged side groups at pH = 7 instead of the neutral ones as done in our previous exploratory paper (Raffaini and Ganazzoli, Langmuir 2003;19:3403–3412). We find that the presence of charges affects somewhat the initial adsorption stage on the electrostatically neutral surface, but not the final one. Thus, we recover the result that a monolayer of aminoacids is eventually formed, with a rough parallelism of distant strands to optimize both the intramolecular and the surface interactions. This feature is consistent with the adsorption on the hydrophobic surface being driven by dispersion forces only, and with the “soft” nature of albumin. Additional optimizations of the final monolayer carried out at pH = 3 and 11 do not modify appreciably this picture, suggesting that adsorption on graphite is basically independent of pH. The enhanced hydration of the final adsorption state due to the (delocalized) charges of the side groups is also discussed in comparison with similar results of the neutralized subdomains. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Effects of Runx2 genetic engineering and in vitro maturation of tissue‐engineered constructs on the repair of critical size bone defects
Authors: Byers Benjamin A. , Guldberg Robert E. , Hutmacher Dietmar W. , García Andrés J. 
Published: November 2005

AbstractGenetic and tissue engineering strategies are being pursued to address the clinical limitations of current bone grafting materials. Based on our previous work demonstrating that overexpression of the Runx2 osteoblastic transcription factor and in vitro construct maturation synergistically enhanced in vivo mineralization in an ectopic site (Byers et al., Tissue Eng 2004;10:1757–1766), we examined the effects of these two parameters on the repair of critical size bone defects. Primary rat bone marrow stromal cells transduced with Runx2 or control (no Runx2 insert) retroviral vector were seeded onto 3D fused deposition‐modeled polycaprolactone scaffolds. Runx2‐modified cells produced biologically‐equivalent mineralized matrices at nearly 2‐fold higher rates than control cells. Constructs cultured in vitro for 1 day (immature) or 21 days (mineralized) were subsequently implanted into critical size calvaria defects in syngeneic rats, and bone healing was analyzed by micro‐CT and histomorphometry at 28 days. Runx2‐modified and control constructs precultured for 1 day healed to a greater extent than defects receiving no implant. Cell‐free scaffolds yielded equivalent levels of bone formation as constructs precultured for 1 day. Interestingly, defects treated with control cell‐seeded constructs precultured for 21 days exhibited low bone formation compared to other construct treatments, and repair was comparable to empty defects. In contrast, Runx2‐modified constructs precultured for 21 days contained twice as much bone as control constructs precultured for 21 days and equivalent levels of new bone as cell‐free and 1 day precultured constructs. These results demonstrate interplay between Runx2 genetically‐modified cells and in vitro construct maturation in bone healing responses. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Detection of biofilm formation in Staphylococcus epidermidis from implant infections. Comparison of a PCR‐method that recognizes the presence of ica genes with two classic phenotypic methods
Authors: Arciola Carla Renata , Campoccia Davide , Baldassarri Lucilla , Donati Maria Elena , Pirini Valter , Gamberini Simonetta , Montanaro Lucio 
Published: November 2005

AbstractBiofilm‐forming ability is increasingly being recognized as an important virulence factor in Staphylococcus epidermidis. This study compares three different techniques for the detection of biofilm‐positive strains. The presence of icaA and icaD genes responsible for biofilm synthesis was investigated by a PCR method in a collection of 80 S. epidermidis strains isolated from orthopedic implant infections. The results from molecular analysis were compared with those obtained by two classic phenotypic methods, the Congo red agar (CRA) plate test and the microtiter plate test (MtP). Fifty‐seven percent of all the examined strains were found icaA/icaD‐positive, of which only three were not positive for CRA test. Differently, by the MtP method, 66% of the strains were found to be biofilm‐producers but only a limited agreement with the PCR‐method was noticeable because of the observation of (icaA/icaD+)/MtP− strains (8%) and of a surprising ambiguous result of (icaA/icaD−)/MtP+ strains (16%). The category of the weak biofilm‐producers provided the highest contribution to these mismatching results (10%). The better agreement between the CRA plate test with the molecular detection of ica genes indicates the former as a reliable test for the phenotypic characterization of virulence of clinical isolates. However, MtP method remains a precious tool for the in vitro screening of different biomaterials for the adhesive properties using a reference strain. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Characterization and bioactivity of tape‐cast and sintered TCP sheets
Authors: Tanimoto Yasuhiro , Hayakawa Tohru , Sakae Toshiro , Nemoto Kimiya 
Published: November 2005

AbstractThe purpose of this study was to investigate the influence of sintering temperature on in vivo and in vitro bioactivities of sintered tricalcium phosphate (TCP) sheets prepared by the tape casting technique. Green sheets of β‐TCP prepared by tape casting were sintered for 2 h in a furnace at atmospheric pressure, at five different sintering temperatures: 900, 1000, 1100, 1150, and 1200°C. Measurement of X‐ray diffraction and Fourier transform infrared spectrometry showed the presence of α‐tricalcium phosphate phase in the TCP sheet sintered at 1200°C, in addition to β‐TCP phase. As compared with the other sintered TCP sheet, the TCP sheet sintered at 1200°C demonstrated a lower dissolution rate in phosphate buffered saline solution at 37°C and pH 7.4 over 24 weeks, and more amount of apatite formation in Hanks' balanced salt solution with pH 7.4 was observed. After 4 weeks' implantation of sintered TCP sheets into tibial diaphyses of rabbits, the bone‐sheet contact of the TCP sheet sintered at 1200°C was significantly higher than that of the TCP sheet sintered at 900°C. These results indicate that a flat sintered TCP sheet prepared by tape casting is a promising material for a bone substitute. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Retrieval analysis of clinical explanted vena cava filters
Authors: Gatti A. M. , Montanari S. 
Published: November 2005

AbstractVena cava filters are the most commonly used mechanical devices to prevent pulmonary embolism. A retrievable permanent filter has been available since 1999. That has allowed the direct study of thrombi captured in humans and the punctual interaction of blood and device at long and short term. Through traditional histologic methods, captured thrombi and the tissues formed around the filter were observed. An innovative environmental scanning electron microscopy technique allowed detection of micro‐ and nanosized foreign bodies inside thrombi and tissues, and chemical analysis could be carried out by means of energy dispersive spectroscopy. All specimens contained different quantities of foreign debris ranging from few tens of microns to 50 nanometers; their chemistry was not homogeneous when patients were compared, and also differed considerably within the same filter. The constant presence of debris deeply embedded in all thrombi observed may mean that they are the cause that triggered the formation of those thrombi as a result of the interaction between foreign bodies and blood components. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Design and delivery of silver sulfadiazine from alginate microspheres‐impregnated collagen scaffold
Authors: Shanmugasundaram N. , Sundaraseelan J. , Uma S. , Selvaraj D. , Babu Mary 
Published: November 2005

AbstractA reconstituted collagen scaffold impregnated with silver sulfadiazine (SSD) loaded alginate microspheres, capable of delivering the drug in a controlled manner has been developed. SSD‐loaded alginate microspheres were prepared by modified water‐in‐oil emulsion technique through interfacial ionic gelation of alginate using CaCl2. The SSD‐loaded microspheres were impregnated in pepsin‐solubilized collagen, in situ, while inducing fibrillation and cast as thin scaffold. Morphological features of microspheres and microsphere‐impregnated collagen were analyzed through SEM. Distribution homogeneity of impregnated microspheres, their in vitro behavior in (Dulbecco's modified minimal essential media) DMEM, and antibacterial efficiency against ATCC pathogens were determined. Initial drug load of 20% (w/w) with respect to alginate and 40% (v/v) of 2% alginate with respect to oil phase were found to produce microspheres of optimum drug entrapment (3%) and required size range (300–370 μm). In vitro drug release studies from the scaffold showed an initial burst release of 47.5% and a controlled release for 72 h with equilibrium concentration of 68.8%. SSD‐loaded microspheres exhibited minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) levels of 32 and 40.2 μg/mL to both K. pneumoniae and E. coli respectively. P. aeruginosa showed MIC and MBC levels of 44.8 and 51.2 μg/mL respectively, while Staphylococcus aureus exhibited MIC and MBC at the same concentration range (57.6 μg/mL). The collagen‐based scaffold impregnated with SSD‐loaded alginate microspheres can deliver SSD in a controlled fashion, can control infection for extended time period with lesser dressing frequencies, and will enable easier assessment of wound. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Gelatin‐based biomimetic tissue adhesive. Potential for retinal reattachment
Authors: Chen Tianhong , Janjua Rabeea , McDermott Martin K. , Bernstein Steven L. , Steidl Scott M. , Payne Gregory F. 
Published: November 2005

AbstractAn adhesive that cures under moist/wet conditions could facilitate surgical procedures for retinal reattachment. We are investigating an adhesive that mimics the factor XIIIa‐mediated crosslinking of fibrin that occurs in the late stages of the blood coagulation cascade. Specifically, we use gelatin as the structural protein (in place of fibrin), and crosslink gelatin using a calcium‐independent microbial transglutaminase (in place of the calcium‐dependent transglutaminase factor XIIIa). Injection of gelatin and microbial transglutaminase (mTG) into the vitreous cavity of Sprague Dawley white rats did not elicit structural or cellular damage to the retina as evidenced from histological evaluation 2 weeks post‐injection. Qualitative in vitro studies indicate that the gelatin–mTG adhesive binds to bovine retinal tissue under wet conditions. Quantitative lap‐shear tests were performed with more robust bovine tissue from the choroid and sclera. The lap‐shear strength of the biomimetic gelatin–mTG adhesive was independent of tissue‐type and ranged from 15 to 45 kPa, which is comparable to the values reported for other soft‐tissue adhesives. These studies suggest that the mTG‐crosslinked gelatin may provide a simple, safe, and effective adhesive for ophthalmic applications. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Microstructure and corrosion behavior of porous coatings on titanium alloy by vacuum‐brazed method
Authors: Lee T.M. , Chang E. , Yen C.H. 
Published: November 2005

AbstractThe microstructural evolution and electrochemical characteristics of brazed porous‐coated Ti‐6Al‐4V alloy were analyzed and compared with respect to the conventionally 1300°C sintering method. The titanium filler metal of low‐melting‐point (934°C) Ti‐15Cu‐15Ni was used to braze commercially pure (CP) titanium beads onto the substrate of Ti‐6Al‐4V alloy at 970°C for 2 and 8 h. Optical microscopy, scanning and transmission electron microscopy, and X‐ray diffractometry (XRD) were used to characterize the microstructure and phase of the brazed metal; also, the potentiostat was used for corrosion study. Experimental results indicate that the bead/substrate contact interface of the 970°C brazed specimens show larger contact area and higher radius curvature in comparison with 1300°C sintering method. The microstructure of brazed specimens shows the Widmanstätten structure in the brazed zone and equiaxed α plus intergranular β in the Ti‐6Al‐4V substrate. The intermetallic Ti2Ni phase existing in the prior filler metal diminishes, while the Ti2Cu phase can be identified for the substrate at 970 for 2 h, but the latter phase decrease with time. In Hank's solution at 37°C, the corrosion rates of the 1300°C sintering and the 970°C brazed samples are similar at corrosion potential (Ecorr) in potentiodynamic test, and the value of Ecorr for the brazed sample is noble to the sintering samples. The current densities of the brazed specimens do not exceed 100 μA/cm2 at 3.5 V (SCE). These results suggest that the vacuum‐brazed method exhibits the potentiality to manufacture the porous‐coated specimens for biomedical application. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
The biocompatibility of silk fibroin films containing sulfonated silk fibroin
Authors: Ma Xilan , Cao Chuanbao , Zhu Hesun 
Published: November 2005

AbstractSulfonation reaction may be an effective method for preparation of heparin‐like materials. However, no sulfonated polymer based on protein backbone was used for improving the blood compatibility of biomaterials. In this study, the biocompatibility of new kind of composite materials films obtained by blending silk fibroin (SF) with sulfonated silk fibroin (SSF) was evaluated. The anticoagulant activity was characterized with prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT), which all increased remarkably, the clot times exceeded the measurement limit of clot detection instrument. Its platelet adhesion was also investigated as another parameter of blood compatibility. The cell compatibility of composite films was evaluated through cell morphologies on the films and cell viability by methyl thiazolyl tetrazolium (MTT) assay. Tensile strength and elongation at break of the composite films reached to 44.6 MPa and 50.3%, respectively. All these results indicated that SF/SSF composite film was a potential material for blood‐contact materials and tissue engineering matrix. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
An in vitro optimized injectable calcium phosphate cement for augmenting screw fixation in osteopenic goats
Authors: Leung Kwok Sui , Siu Wing Sum , Li Siu Fai , Qin Ling , Cheung Wing Hoi , Tam Kam Fai , Lui Pauline Po Yee 
Published: November 2005

AbstractThis study reports the proportioning and standardized mixing procedures for preparing a hydroxylapatite cement (tetracalcium phosphate and dicalcium phosphate) of desired viscosity and mechanical strength reproducibly for application in trauma surgery. The behavior and the biomechanical properties of the resulting bone cement in screw augmentation were then evaluated in our osteopenic goat model. The use of a shaker standardized the mixing procedure. The optimal volume of Na2HPO4 used to prepare the injectable cement was 0.45 mL/g, with averaged in vitro compressive strength of 48.29 ± 5.62 MPa. Histology showed increasing tightly‐coupled bone apposition on the cement surface without fibrous encapsulation as observed in the screw‐only controls with time in the osteopenic goat model. The cement increased the initial screw pull‐out force (54.7%, p = 0.005) significantly and the energy required to failure (54.7%, p < 0.05) significantly, and remained higher than the screw‐only controls after 3 months (9.8% and 20.2%, respectively) and 6 months (20.2% and 44.7%, respectively). These results imply potential in the prevention of interfacial micromotions and subsequent fibrous tissue formation at the implant–bone interface resulting in a decreased risk of implant failure. The optimized cement in this study may serve as a good candidate for augmenting fixation of osteoporotic bone. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Fatigue debonding of the roughened stem–cement interface: Effects of surface roughness and stem heating conditions
Authors: Damron Leatha A. , Kim Do‐Gyoon , Mann Kenneth A. 
Published: November 2005

AbstractThe aim of this study was to determine the effects of cyclic loading on the debond process of a roughened stem–cement interface used in total hip arthroplasty. The specific goals were to assess the effects of two surgeon‐controlled variables (stem heating and degree of stem surface roughness) and to determine if an independent finite element‐based fracture mechanics model could be used to predict the debond response. A clamped cantilever beam geometry was used to determine the fatigue debond response of the stem–cement interface and was created using an experimental mold that simulated in vivo cementing conditions. A second experiment was performed using a torsion‐loading model representative of the stem–cement–bone composite. For both experiments, two stem heating (room temperature and 50°C) and surface roughness conditions (grit blasted: Ra = 2.3 and 5.1 μm) were used. Finally, a finite element model of the torsion experiment with provision for crack growth was developed and compared with the experimental results. Results from both experiments revealed that neither stem preheating nor use of a stem with a greater surface roughness had a marked effect on the fatigue debond response. There was substantial variability in the debond response for all cases; this may be due to microscopic gaps at the interface for all interface conditions. The debond rate from the finite element simulation (10−7.31 m/cycle) had a magnitude similar to the experimental torsion model (10−(6.77 ± 1.25) m/cycle). This suggests that within the context of the experimental conditions studied here that the debond response could be assessed using a linear elastic fracture mechanics‐type approach. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Types of superregular matrices and the number ofn‐arcs and completen‐arcs in PG (r, q)
Authors: Kéri Gerzson 
Published: November 2005

AbstractBased on the classification of superregular matrices, the numbers of non‐equivalentn‐arcs and completen‐arcs in PG(r,q) are determined (i) for 4 ≤ q ≤ 19, 2 ≤ r ≤ q − 2 and arbitraryn, (ii) for 23 ≤ q ≤ 32,r = 2 andn ≥ q − 8<$>. The equivalence classes over both PGL (k,q) and PΓL(k,q) are considered throughout the examinations and computations. For the classification, ann‐arc is represented by the systematic generator matrix of the corresponding MDS code, without the identity matrix part of it. A rectangular matrix like this is superregular, i.e., it has only non‐singular square submatrices. Four types of superregular matrices are studied and the non‐equivalent superregular matrices of different types are stored in databases. Some particular results ont(r,q) andm′(r,q)—the smallest and the second largest size for complete arcs in PG(r,q)—are also reported, stating thatm′(2, 31) = 22,m′(2, 32) = 24,t(3, 23) = 10, andm′(3, 23) = 16. © 2006 Wiley Periodicals, Inc. J Combin Designs 14: 363–390, 2006
Role of the RANKL/RANK system in the induction of interleukin‐8 (IL‐8) in B chronic lymphocytic leukemia (B‐CLL) cells
Authors: Secchiero Paola , Corallini Federica , Barbarotto Elisa , Melloni Elisabetta , di Iasio Maria Grazia , Tiribelli Mario , Zauli Giorgio 
Published: November 2005

AbstractB chronic lymphocytic leukemia (B‐CLL) cells express several members of the tumor necrosis factor (TNF) family, such as CD40L, CD30L, and TRAIL. By using the cDNA microarray technology, B‐CLL samples were found to overexpress receptor activator of nuclear factor kB (NF‐kB) ligand (RANKL), as compared to normal CD19+ B cells. These findings were validated at the protein level by Western blot and flow cytometry analyses. Moreover, unlike primary normal B cells, leukemic B‐CLL cells showed surface expression of RANK, the cognate transmembrane receptor of RANKL. When added in vitro to B‐CLL cultures, either alone or in association with chlorambucil or fludarabine, recombinant RANKL did not significantly modulate cell viability, and it minimally affected the IL‐8 expression/release. On the other hand, treatment with RANK‐Fc chimera potently upregulated the release of IL‐8 in the B‐CLL culture supernatants, suggesting involvement of reverse signaling through transmembrane RANKL in IL‐8 induction. In turn, exposure of B‐CLL cells to recombinant IL‐8 significantly decreased spontaneous apoptosis as well as chlorambucil‐ and fludarabine‐mediated cytoxicity in B‐CLL cells. Since IL‐8 has been implicated in progression of B‐CLL disease, our findings suggest that, by upregulating IL‐8, the RANKL/RANK system may contribute to the pathogenesis of B‐CLL. J. Cell. Physiol. 207: 158–164, 2006. © 2005 Wiley‐Liss, Inc.