bluuebunny/crossref_metadata_2025_split huggingface dataset:
PEOT/PBT based scaffolds with low mechanical properties improve cartilage repair tissue formation in osteochondral defects
Authors: Jansen Edwin J. P. , Pieper Jeroen , Gijbels Marion J. J. , Guldemond Nick A. , Riesle Jens , Van Rhijn Lodewijk W. , Bulstra Sjoerd K. , Kuijer Roel 
Published: April 2008

AbstractThe aim of our study was to compare the healing response of biomechanically and biochemically different scaffolds in osteochondral defects created in rabbit medial femoral condyles. A block copolymer comprised of poly(ethylene oxide terephthalate) and poly(butylene terephthalate) was used to prepare porous scaffolds. The 70/30 scaffold (70 wt % poly(ethylene oxide terephthalate)) was compared to the stiffer 55/45 (55 wt % poly(ethylene oxide terephthalate)) scaffold. Nine 6‐month‐old rabbits were used. Osteochondral defects were filled with 55/45 scaffolds (n = 6); 70/30 scaffolds (n = 6); or left empty (n = 6). Defect sites were allowed to heal for 12 weeks. Condyles were macroscopically evaluated and analysed histologically using the O'Driscoll score for evaluating repair of osteochondral defects. Repair tissue in 70/30 scaffolds consisted of cartilage‐like tissue on top of trabecular bone, whereas the tissue within the 55/45 scaffolds consisted predominantly of trabecular bone. O'Driscoll scores for 70/30 scaffolds were significantly better (p = 0.024) in comparison to untreated osteochondral defects and 55/45 scaffolds. This study reveals that the biomechanical and biochemical properties of the scaffold play an important role by themselves, and can affect the healing response of osteochondral defects. Scaffolds with low mechanical properties were superior in cartilage repair tissue formation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Study of hydroxyapatite osteoinductivity with an osteogenic differentiation of mesenchymal stem cells
Authors: Lin Liwen , Chow King L. , Leng Yang 
Published: April 2008

AbstractOsteoinductivity of hydroxyapatite (HA) was investigated using uncommitted pluripotent mouse stem cells, C3H10T1/2 in an in vitro differentiation assay. For comparative analysis, the cells were cultured on substrates made of osteoinductive HA, with biocompatible titanium and plastics as the negative control. HA exhibited the ability to induce expression of osteo‐specific genes in C3H10T1/2, including alkaline phosphatase (ALP), type I collagen, and osteocalcin; compared with its insignificant up‐regulation of the same genes in osteoblast‐like cells, Saos‐2. HA osteoinductivity exhibited in C3H10T1/2 was comparable to that of a bone morphogenetic protein (BMP) with reference to the up‐regulation of osteo‐specific genes except the core binding factor 1 (Cbfa1, Runx). This result implies a difference in osteogenic induction pathway initiated by HA and BMP. Using this mesenchymal stem cells (MSC) culture assay, osteoinductivity was also demonstrated to be present in the conditioned medium derived from MSC cultured on HA substrates. This conditioned medium exhibited excellent ability to up‐regulate ALP in the absence of HA and BMP. The results suggest that the HA can interact with the cells and generate potent inductive substance released into the medium. Such substance in turn is able to induce uncommitted cells to differentiate into the osteolineage. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Comparative in vivo evaluation of porous and dense duplex titanium and hydroxyapatite coating with high roughnesses in different implantation environments
Authors: Borsari V. , Fini M. , Giavaresi G. , Tschon M. , Chiesa R. , Chiusoli L. , Salito A. , Rimondini L. , Giardino R. 
Published: April 2008

AbstractTi (PG60) and Ti plus HA (HPG60) dense coatings with ultrahigh roughness (Ra: 74 ± 8 μm and 53 ± 18 μm, respectively) were compared to high Ti (Ti60) and Ti plus HA (HT60) high roughened porous coatings (Ra: 40 ± 7 μm and 36 ± 3 μm, respectively). Surfaces were implanted in cortical and trabecular bone of young adult (YOUNG), aged (AGED) and estrogen‐deficient sheep (OVX) and analyzed by means of histology, histomorphometry and push‐out tests 3 months after implantation. A significantly lower value in affinity index (AI) of PG60 when compared to TI60 (p < 0.01) was observed in cortical bone. In trabecular bone, lower values in AI were found in TI60 and PG60 when compared to their HA‐coated surfaces (p < 0.0005). Bone ingrowth (BI) of TI60 and PG60 was significantly lower than that of the HA‐coated surfaces in trabecular bone (p < 0.05). Significantly lower values in BI in OVX sheep in comparison to YOUNG sheep in both cortical and trabecular bone were observed (p < 0.05). Data showed that high roughness and Ti and HA‐coated surfaces are suitable for aged and osteoporotic patients. HA coatings represent the most successful strategy in trabecular bone. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Response of human osteoblasts exposed to wear particles generated at the interface of total hip stems and bone cement
Authors: Lenz Robert , Mittelmeier Wolfram , Hansmann Doris , Brem Regina , Diehl Peter , Fritsche Andreas , Bader Rainer 
Published: April 2008

AbstractAseptic loosening of total hip replacement is mainly caused by wear particles. Abrasive wear occurs at articulating surfaces or as a consequence of micro‐motions at the interface between femoral stem and bone cement. Direct impact of wear particles on osteolysis, the remodeling of the bone stock and a directly affected function of osteoblasts was described. The present study examined the response of human osteoblasts exposed to different wear particles, which were generated in a test device providing oscillating micro‐motions at the interface between femoral stem and standard bone cement. Characterization of released particles was performed by quantifying the size distribution and the metal content of the wear debris. Human osteoblasts were incubated with particles obtained from hip stems with different material compositions (Ti‐6Al‐7Nb and Co‐28Cr‐6Mo) and rough and smooth surface finishings combined with standard bone cement (Palacos® R) containing zirconium oxide particles. Commercially pure titanium particles (cp‐Ti) and particulate zirconium oxide (ZrO2) were used for comparative analyses. The results revealed significant (p < 0.05) reduction of the cell viability after exposure to higher concentration of metallic particles, particularly from Co‐based alloys. In contrast, ZrO2 alone showed significantly less adverse effects on the cells. When increasing metallic particle concentrations massive inhibition was also observed in the release of cytokines including interleukine‐6 (IL‐6) and interleukine‐8 (IL‐8), but the expression of Procollagen I and the cell viability showed the highest reduction after exposure to Co‐based alloy particles from rough stems. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Bond strength of adhesively luted ceramic discs to different core materials
Authors: Bozogullari Nalan , Inan Ozgur , Usumez Aslihan 
Published: April 2008

AbstractThe purpose of this in vitro study was to compare the shear bond strengths of resin, glass‐ionomer, and ceramic‐based core materials to all ceramic discs. Five core materials (Core max, Sankin; Clearfil AP‐X, Kuraray; Empress Cosmo, Ivoclar‐Vivadent; Photocore, Kuraray; Dyract Extra, Dentsply) were prepared as discs 10 mm in diameter and 2 mm in height according to the manufacturer's instructions. Ten disc specimens per group were prepared, and dentin served as the control. All resin specimens were embedded in autopolymerizing acrylic resin, with one surface facing up. All ceramic discs (IPS Empress I, Ivoclar‐Vivadent) 3 mm in diameter and 2 mm in height were prepared and bonded to core specimens with a dual‐curing luting resin cement (Variolink II, Vivadent). Specimens were stored in distilled water at 37°C. Shear bond strength of each sample was measured after 24 h using a universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed with one‐way analysis of variance and Tukey HSD tests (α = 0.05). Shear bond strength varied significantly depending on the core material used (p < 0.05). Clearfil AP‐X and Photocore showed the highest shear bond strength value while Empress Cosmo provided the lowest (p < 0.05). There were no statistically significant differences among Clearfil AP‐X, Photocore, and Core‐Max (p > 0.05). And also there were no statistically significant differences between Dyract Extra and the control group (p > 0.05). In vitro shear bond strengths of ceramic discs bonded to resin‐based core materials showed higher bond strength values than ceramic‐based core material. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Differential fine‐tuning of cochlear implant material–cell interactions by femtosecond laser microstructuring
Authors: Reich Uta , Mueller Peter P. , Fadeeva Elena , Chichkov Boris N. , Stoever Timo , Fabian Tilman , Lenarz Thomas , Reuter Guenter 
Published: April 2008

AbstractCochlear implants (CIs) can restore hearing in deaf patients by electrical stimulation of the auditory nerve. To optimize the electrical stimulation, the number of independent channels must be increased by reduction of connective tissue growth on the electrode surface and selective neuronal cell contact. The femtosecond laser microstructuring of the electrode surfaces was performed to investigate the effect of fibroblast growth on the implant material. A cell culture model system was established to evaluate cell–material interactions on these microstructured CI‐electrode materials. Fibroblasts were used as a cell culture model for connective tissue formation, and differentiating neuronal‐like cells were employed to represent neuronal cells. For nondestructive microscopic examination of living cells on the structured surfaces, the cells were genetically modified to express green fluorescent protein. To investigate the special interaction between the electrode material and the tissue we used electrode material which is originally used for manufacturing CI for human applications, namely platinum (contact material) and silicone carrier material (LSR 30, HCRP 50). Microstructures of various dimensions (groove width 1–10 μm) were generated by using femtosecond laser ablation. The highest fibroblast growth rate was observed on platinum, but cell growth rates on the silicone carrier material were lower. Microstructuring reduced fibroblast cell growth on platinum significantly. On the microstructured silicone, a trend to lower cell growth rates was observed. In addition, microgrooves on platinum surfaces can direct neurite outgrowth parallel to the grooves. The implications of the results are discussed with respect to the design of a microstructured CI surface. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Hierarchically mesoporous–macroporous bioactive glasses scaffolds for bone tissue regeneration
Authors: Yun Hui‐suk , Kim Seung‐eon , Hyun Yong‐taek , Heo Su‐jin , Shin Jung‐wook 
Published: April 2008

AbstractHierarchically 2D/3D mesoporous–macroporous bioactive glasses (MMBG) with good molding capabilities and compressive modulus were synthesized by sol–gel method and evaporation‐induced self‐assembly process in the presence of both nonionic triblock copolymers, EO70PO20EO70 (P123) or EO100PO65EO100 (F127), templates and methyl cellulose template. P123 or F127 acts as both a template, inducing the formation of mesopore, and an effective dispersant of MC, which produces macropores. In vitro bioactivity studies were carried out in simulated body fluid and showed superior bone‐forming bioactivities of hierarchical MMBG. Human osteoblastlike cells, MG63, were seeded on MMBG and were determined using MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5,‐diphenyl‐tetrazolium bromide] assay to confirm biocompatibilities of MMBG. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Infinite families of non‐embeddable quasi‐residual Menon designs
Authors: Alraqad Tariq , Shrikhande Mohan 
Published: April 2008

AbstractA Menon design of order h2 is a symmetric (4h2,2h2‐h,h2‐h)‐design. Quasi‐residual and quasi‐derived designs of a Menon design have parameters 2‐(2h2 + h,h2,h2‐h) and 2‐(2h2‐h,h2‐h,h2‐h‐1), respectively. In this article, regular Hadamard matrices are used to construct non‐embeddable quasi‐residual and quasi‐derived Menon designs. As applications, we construct the first two new infinite families of non‐embeddable quasi‐residual and quasi‐derived Menon designs. © 2008 Wiley Periodicals, Inc. J Combin Designs 17: 53–62, 2009
Fermentative production of L(+)‐lactic acid from starch hydrolyzate and corn steep liquor as inexpensive nutrients by batch culture of Enterococcus faecalis RKY1
Authors: Wee Young‐Jung , Reddy L V A , Ryu Hwa‐Won 
Published: April 2008

AbstractBACKGROUND: Attempts were made to determine the lactic acid production efficiency of novel isolate, Enterococcus faecalis RKY1 using four different starches (corn, tapioca, potato, and wheat starch) with different concentrations (50, 75, 100, and 125 g L−1) and corn steep liquor as an inexpensive nitrogen source.RESULTS: The yield of lactic acid from each starch was higher than 95% based on initial starch concentrations. High lactic acid concentration (129.9 g L−1) and yield (1.04 g‐lactic acid g−1‐starch) were achieved faster (84 h) from 125 g L−1 of corn starch. Among the starches used, tapioca starch fermentation usually completed in a shorter incubation period. The final dry cell weight was highest (7.0 g L−1) for the medium containing 75 g L−1 of corn starch, which resulted in maximum volumetric productivity of lactic acid (3.6 g L−1 h−1). The addition of 30 g L−1 corn steep liquor supplemented with a minimal amount of yeast extract supported both cell growth and lactic acid fermentation.CONCLUSION: Enterococcus faecalis RKY1 was found to be capable of growing well on inexpensive nutrients and producing maximum lactic acid from starches and corn steep liquor as lower‐cost raw materials than conventionally‐used refined sugars such as glucose, and yeast extract as an organic nitrogen source in laboratory‐scale studies. These fermentation characteristics are prerequisites for the industrial scale production of lactic acid. Copyright © 2008 Society of Chemical Industry
Hypospadias mimicking female genitalia on early second trimester sonographic examination
Authors: Odeh Marwan , Ophir Ella , Bornstein Jacob 
Published: April 2008

AbstractFemale fetal sex was assigned based on downward direction of the genital tubercle at 14 weeks' gestation. Subsequently, amniocentesis performed due to the finding of an echogenic focus in the left ventricle revealed a male karyotype. Sonographic examination at 22 weeks' gestation revealed a markedly curved penile shaft. Power Doppler at that time demonstrated a urine jet emanating from the penile base, verifying the diagnosis of penoscrotal hypospadias. We therefore suggest that female fetal sex assignment should be based on the demonstration of the 2 or 4 parallel lines representing the labial folds and not only upon the demonstration of the downward direction of the genital tubercle. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound 36:581–583, 2008
On two questions about circular choosability
Authors: Norine Serguei 
Published: April 2008

AbstractWe answer two questions of Zhu on circular choosability of graphs. We show that the circular list chromatic number of an even cycle is equal to 2 and give an example of a graph for which the infimum in the definition of the circular list chromatic number is not attained. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:261‐269, 2008
‘Green earths’: vibrational and elemental characterization of glauconites, celadonites and historical pigments
Authors: Ospitali Francesca , Bersani Danilo , Di Lonardo Gianfranco , Lottici Pier Paolo 
Published: April 2008

Abstract‘Green earths’ are employed since antiquity as pigments in the creation of artworks. The minerals responsible for the colour belong to four groups: (1) the clayey micas celadonite and glauconite, undoubtedly the most common; (2) smectites; (3) chlorites; (4) serpentines. Whereas there have been several studies on clayey materials, mineralogical analyses in the field of cultural heritage are mainly limited to the identification of the green earth without specific characterization of the mineralogical species. This work shows a preliminary characterization by the multi‐techniques approach of some raw minerals (glauconite, celadonite and ferroceladonite).Vibrational analyses have been correlated with elemental analyses, thanks to the hyphenated instrumentation of scanning electron microscopy with EDS and Raman structural and chemical analyser (SEM‐EDS‐SCA) probes, which permitted collection of EDS and Raman spectra on the same microscopic area. Micro‐Raman and Fourier transform infrared attenuated total reflectance (FTIR‐ATR) spectroscopies were able to distinguish between celadonite and glauconite. The use of different lasers revealed resonance effects in the Raman spectra. In addition to pure minerals, archaeological samples and commercial green earths were also analysed, thereby enabling a more precise classification of the green pigments in heterogeneous samples such as wall paintings. Some commercially available green earths were found to contain organic dyes. Copyright © 2008 John Wiley & Sons, Ltd.
Study on characterization and properties of nanosilica‐filled thermoplastic vulcanizates
Authors: Chatterjee K. , Naskar K. 
Published: April 2008

AbstractThermoplastic vulcanizates (TPVs) are a special class of thermoplastic elastomer, produced by simultaneously mixing and cross‐linking a rubber with a thermoplastic at elevated temperature. Dicumyl peroxide‐cured TPVs based on blends of maleated ethylene propylene rubber (m‐EPM) and polypropylene (PP) thermoplastic using maleated‐PP as a compatibilizer have been developed. To reinforce the properties of these TPVs, nanosilica was added at different levels. With the increase of nanosilica concentrations, significant improvement in tensile strength, modulus, and impact strength of TPVs have been achieved. Morphology study shows that nanosilica is uniformly dispersed in the polymer matrices. Dynamic mechanical analysis shows that tan δ value at low temperature decreases with increasing nanosilica concentration indicating less damping characteristics. Thermogravimetric study revealed that thermal stability of TPVs is improved in presence of nanosilica. Equilibrium swelling study confirms that solvent resistance of TPVs could be improved by nanofiller incorporation. Rubber process analyzer found a very useful tool to understand the melt rheology of nanosilica filled TPVs in terms of dynamic functions over a wide range of strain amplitude and frequency. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Prediction of processability at extrusion coating for low‐density polyethylene
Authors: Kouda Shingo 
Published: April 2008

AbstractThe neck‐in level and the maximum drawdown speed at extrusion coating for low‐density polyethylene are studied with the evaluation of the rheological properties in the molten state and the dilute solution properties. It is found that the viscous properties in the molten state and the dilute solution properties are not sensitive to the processability, whereas the elastic nature has a great impact. In particular, the elastic response in the nonlinear region, such as drawdown force and strain‐hardening behavior in elongational viscosity, can be employed for the prediction of the processability at extrusion coating. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Characterization of processing effects in HIPS‐CNF composites using thermogravimetric analysis
Authors: Kota Arun K. , Kerzner Rachel , Bigio David I. , Bruck Hugh A. , Powell Dan 
Published: April 2008

AbstractTo completely establish the processing–structure–property relationships of polymer composites such as Carbon Nanofibers (CNFs) in high‐impact polystyrene, it is necessary to understand the effects of different processes and processing conditions on the properties of the composites. In this work, using thermogravimetric analysis, the effects of solvent processing and twin‐screw extrusion on the weight loss rates and the corresponding temperatures were studied. While there were only marginal effects of the CNF concentration, the type of processing significantly affected the thermo‐oxidative behavior. Extrusion resulted in composites that had better thermal stability compared to the solvent processed ones. Furthermore, higher shear rates in extrusion also led to composites with higher thermal stability. This has important implications in choosing the appropriate process and processing conditions for producing polymer‐CNF composites. It was also demonstrated that thermogravimetric analysis can provide a means of characterizing the degree of dispersion resulting from the processing of the composites that complements conventional microscopy techniques. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Characterization and thermal degradation of polyimides derived from ODPA and several alicyclic‐containing diamines
Authors: Chen Chao‐Feng , Qin Wei‐Min , Huang Xiang‐An 
Published: April 2008

AbstractThermal properties of polyimides with main chain containingalicyclic units derived from 3,3′ 4,4′‐oxydiphthalic anhydride (ODPA) and several alicyclic‐ containing diamine monomers, including 1,4‐bis (4‐aminophenoxymethylene) cyclohexane (BAMC), 1,4‐bis (3‐aminophenoxymethylene) cyclohexane (mBAMC), 1,4‐bis (4‐aminobenzoyoloxymethyl) cyclohexane (BAZMC), and 1,4‐bis (3‐aminobenzoyoloxymethyl) cyclohexane (mBAZMC) were characterized in detail. The thermal stability, apparent activation energy, and evolved gas analysis of these polyimides were done using thermogravimetric analysis (TGA) coupled with Fourier transform infrared (FTIR) spectroscopy. Experimental results indicated that the resulting polyimides showed fairly high thermal stability, no weight loss was detected before a temperature of 400°C in nitrogen, and the values of glass‐transition temperature of them were in the range of 134–181°C. Activation energy for the initial thermal degradation of polyimide derived from ODPA and mBAMC in nitrogen were 166 and 162 kJ/mol in two different methods. The TG‐IR results represented that the major evolved products from the nonoxidative thermal degradation were detected to be hydrocarbons, CO, CO2, H2O, and aromatic compounds. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.