bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of modified gold surfaced titanium implants on skeletal fixation
Authors: Zainali Kasra , Danscher Gorm , Jakobsen Thomas , Baas Jorgen , Møller Per , Bechtold Joan E. , Soballe Kjeld 
Published: July 2012

AbstractNoncemented implants are the primary choice for younger patients undergoing total hip replacements. However, the major concern in this group of patients regarding revision is the concern from wear particles, periimplant inflammation, and subsequently aseptic implant loosening. Macrophages have been shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti‐inflammatory manner by inhibiting cellular NF‐κB‐DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration and increase mechanical fixation. Cylindrical porous coated Ti‐6Al‐4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out tests and stereological histomorphometrical analyses showed no statistically significant differences in the two groups. The unchanged parameters are considered an improvement of the coating properties, as a previous complete gold‐coated implant showed inferior mechanical fixation and reduced osseointegration compared to control titanium implants in a similar model. Since sufficient early mechanical fixation is achieved with this new coating, it is reasonable to investigate the implant further in long‐term studies. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:195–202, 2013.
Correlating macrophage morphology and cytokine production resulting from biomaterial contact
Authors: Lee Hyun‐Su , Stachelek Stanley J. , Tomczyk Nancy , Finley Matthew J. , Composto Russell J. , Eckmann David M. 
Published: July 2012

AbstractThe morphological and inflammatory responses of adherent macrophages are correlated to evaluate the biocompatibility of surfaces. Monocyte‐derived macrophage (MDM), THP‐1, and THP‐1 cells expressing GFP‐actin chimeric protein were seeded onto glass, polyurethane (PU), and glass surface modified with quaternary ammonium salt functionalized chitosan (CH‐Q) and hyaluronic acid (HA). Using confocal microscopy, the surface area, volume and 3D shape factor of adherent macrophages was quantified. For comparison, functional consequences of cell‐surface interactions that activate macrophages and thereby elicit secretion of a proinflammatory cytokine were evaluated. Using an enzyme linked immune sorbent assay, tumor necrosis factor‐alpha (TNF‐α) was measured. On glass, macrophages exhibited mainly an amoeboid shape, exhibited the largest surface area, volume, and 3D shape factor and produced the most TNF‐α. On PU, macrophages displayed mainly a hemispherical shape, exhibited an intermediate volume, surface area and 3D shape factor, and produced moderate TNF‐α. In contrast, on CH‐Q and HA surfaces, macrophages were spherical, exhibited the smallest volume, surface area, and 3D shape factor, and produced the least TNF‐α. These studies begin to validate the use of GFP‐actin‐modified MDM as a novel tool to correlate cell morphology with inflammatory cell response. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:203–212, 2013.
Modulating patterned adhesion and repulsion of HEK 293 cells on microengineered parylene‐C/SiO2 substrates
Authors: Hughes M. A. , Bunting A. S. , Cameron K. , Murray A. F. , Shipston M. J. 
Published: July 2012

AbstractThis article describes high resolution patterning of HEK 293 cells on a construct of micropatterned parylene‐C and silicon dioxide. Photolithographic patterning of parylene‐C on silicon dioxide is an established and consistent process. Activation of patterns by immersion in serum has previously enabled patterning of murine hippocampal neurons and glia, as well as the human hNT cell line. Adapting this protocol we now illustrate high resolution patterning of the HEK 293 cell line. We explore hypotheses that patterning is mediated by transmembrane integrin interactions with differentially absorbed serum proteins, and also by etching the surface substrate with piranha solution. Using rationalized protein activation solutions in place of serum, we show that cell patterning can be modulated or even inverted. These cell‐patterning findings assist our wider goal of engineering and interfacing functional neuronal networks via a silicon semiconductor platform. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Ring‐opening polymerization of genipin and its long‐range crosslinking effect on collagen hydrogel
Authors: Mu Changdao , Zhang Ke , Lin Wei , Li Defu 
Published: July 2012

AbstractPolymeric genipin macromers, prepared by ring‐opening polymerization at various pH values, are used as crosslinking agents to fix collagen hydrogels. The results indicate that as the dark color of polymeric genipin itself and the networks formed by long‐range intermolecular crosslinking, the genipin‐fixed collagen hydrogels displace darker color. The polymeric genipin prepared at higher pH value needs longer time to fully crosslink with collagen molecules. Moreover, polymerization of genipin reduces the yield of genipin‐fixed collagen hydrogels due to low extent of crosslinking. Specially, the microscope photographs present the porous networks structures of genipin‐fixed collagen hydrogels. The pore size increases with the increase in polymerization degree of genipin. The data of FTIR indicate the likely transition of –NH2 groups in collagen chains into C=N. Owning to much more number of hydrophilic groups and more porous networks, collagen hydrogels fixed by genipin with higher polymerization degree have higher water absorption capacity. The equilibrium swelling of genipin‐fixed collagen hydrogels is pH‐responsive, which show “M” type changes with the pH values. The results obtained in the study suggest that the polymeric genipin prepared at various pH values lead to significant influence to the crosslinking characteristics and properties of collagen hydrogels. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Tensile testing as a novel method for quantitatively evaluating bioabsorbable material degradation
Authors: Bowen Patrick K. , Gelbaugh Jesse A. , Mercier Phillip J. , Goldman Jeremy , Drelich Jaroslaw 
Published: July 2012

AbstractBioabsorbable metallic materials have become a topic of interest in the field of interventional cardiology because of their potential application in stents. A well‐defined, quantitative method for evaluating the degradation rate of candidate materials is currently needed in this area. In this study, biodegradation of 0.25‐mm iron and magnesium wires was simulated in vitro through immersion in cell‐culture medium with and without a fibrin coating (meant to imitate the neointima). The immersed samples were corroded under physiological conditions (37°C, 5% CO2). Iron degraded in a highly localized manner, producing voluminous corrosion product while magnesium degraded more uniformly. To estimate the degradation rate in a quantitative manner, both raw and corroded samples underwent tensile testing using a protocol similar to that used on polymeric nanofibers. The effective ultimate tensile stress (tensile stress holding constant cross‐sectional area) was determined to be the mechanical metric that exhibited the smallest amount of variability. When the effective tensile stress data were aggregated, a statistically significant downward, linear trend in strength was observed in both materials (Fe and Mg) with and without the fibrin coating. It was also demonstrated that tensile testing is able to distinguish between the higher degradation rate of the bare wires and the lower degradation rate of the fibrin‐coated wires with confidence. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Characterization and preosteoblastic behavior of hydroxyapatite‐deposited nanotube surface of titanium prepared by anodization coupled with alternative immersion method
Authors: Gu Ying‐Xin , Du Juan , Zhao Jing‐Mei , Si Mi‐Si , Mo Jia‐Ji , Lai Hong‐Chang 
Published: July 2012

AbstractThe modification on the titanium (Ti) implant surface is an effective method to improve the bioactivity of Ti. In this study, a hydroxyapatite (HA)‐deposited nanotubular Ti surface was prepared by anodization coupled with an alternative immersion method (AIM). Surface physicochemical characteristics including morphology, microstructure, composition, roughness were evaluated by field‐emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), Fourier‐transformed infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Preosteoblast cell (MC3T3‐E1) behavior on the HA‐deposited nanotube surface, including cell morphology, proliferation, alkaline phosphatase (ALP) activity, osteocalcin secretion, and mineralization, were also investigated. The untreated nanotube surface and bare Ti were used as controls. The results showed that synthetic HA crystals could be efficiently grown on/inside the nanotubes after AIM treatment in saturated Ca(OH)2 and 0.02M (NH4)2HPO4. The amount of synthetic HA on nanotube layer was dependent on the number of dipping cycles. Significant increases in ALP activity and osteocalcin production on day 7 and 14 and calcium deposition on day 21 (P < 0.05) were observed for HA‐deposited nanotubular Ti surface when compared with untreated nanotube layer and bare Ti. However, the cell proliferation rate on HA‐deposited nanotube surfaces was slowed down significantly (P < 0.05). All these results indicated that this HA‐deposited nanotube surface might have the potential benefit to enhance implant osseointegration. The synthetic HA TiO2 nanotube loading might be a highly promising path to improve the bioactivity of Ti‐based implants. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
GPU‐accelerated computation of electron transfer
Authors: Höfinger Siegfried , Acocella Angela , Pop Sergiu C. , Narumi Tetsu , Yasuoka Kenji , Beu Titus , Zerbetto Francesco 
Published: July 2012

AbstractElectron transfer is a fundamental process that can be studied with the help of computer simulation. The underlying quantum mechanical description renders the problem a computationally intensive application. In this study, we probe the graphics processing unit (GPU) for suitability to this type of problem. Time‐critical components are identified via profiling of an existing implementation and several different variants are tested involving the GPU at increasing levels of abstraction. A publicly available library supporting basic linear algebra operations on the GPU turns out to accelerate the computation approximately 50‐fold with minor dependence on actual problem size. The performance gain does not compromise numerical accuracy and is of significant value for practical purposes. © 2012 Wiley Periodicals, Inc.
On Perfect 2‐Colorings of Johnson Graphs J(v, 3)
Authors: Gavrilyuk Alexander L. , Goryainov Sergey V. 
Published: July 2012

AbstractWe study the perfect 2‐colorings (also known as the equitable partitions into two parts or the completely regular codes with covering radius 1) of the Johnson graphs . In particular, we classify all the realizable quotient matrices of perfect 2‐colorings for odd v. © 2012 Wiley Periodicals, Inc. J. Combin. Designs 21: 232–252, 2013
Comparison of 0.5M gadoterate and 1.0M gadobutrol in peripheral MRA: A prospective, single‐center, randomized, crossover, double‐blind study
Authors: Haneder Stefan , Attenberger Ulrike I. , Schoenberg Stefan O. , Loewe Christian , Arnaiz Javier , Michaely Henrik J. 
Published: July 2012

AbstractPurpose:To evaluate the diagnostic efficacy of macrocyclic paramagnetic gadolinium (Gd) chelates gadoterate (0.5 mmol/mL) and gadobutrol (1.0 mmol/mL) for the diagnosis of clinically significant abdominal/lower limb arterial diseases at 3.0T.Materials and Methods:This study was conducted as a prospective, single‐center, randomized, double‐blind, intraindividual study comparing single dose (0.1 mmol/kg) gadoterate enhanced‐MRA (magnetic resonance angiography) with gadobutrol enhanced‐MRA at 3.0T for their diagnostic potential in patients with peripheral artery disease. A total of 20 patients were included in this trial.Results:Fourteen patients were eligible for the final efficacy analysis. The overall image quality (excellent/more than adequate) was better rated with gadoterate than with gadobutrol (100% vs. 78.6%, 100% vs. 92.9%, 100% vs. 85.7%, 100% vs. 85.7% for readers 1, 2, 3, 4, respectively). Diagnostic confidence was rated high/excellent in 100% (readers 1, 2, and 3) and 92.9% (reader 4) with gadoterate compared to 92.9% (readers 1 and 2) and 85.7% (readers 3 and 4) with gadobutrol. Higher signal‐to‐noise ratio (SNR) and contrast‐to‐noise ratio (CNR) values were obtained for gadobutrol compared to gadoterate (26.1/23.4, P = 0.01, and 22.7/20.2, P = 0.01). For the secondary criteria, no differences between groups were reported. No adverse events were reported.Conclusion:Gadobutrol yielded significantly higher SNR/CNR while gadoterate was better rated in terms of overall image quality and diagnostic confidence (P > 0.05). J. Magn. Reson. Imaging 2012;36:1213–1221. © 2012 Wiley Periodicals, Inc.
1H‐nuclear magnetic resonance‐based metabonomic analysis of brain in rhesus monkeys with morphine treatment and withdrawal intervention
Authors: Deng Yi , Bu Qian , Hu Zhengtao , Deng Pengchi , Yan Guangyan , Duan Jiachuan , Hu Chunyan , Zhou Jiaqing , Shao Xue , Zhao Jinxuan , Li Yan , Zhu Ruiming , Zhao Yinglan , Cen Xiaobo 
Published: July 2012

AbstractComprehensive cerebral metabolites involved in morphine dependence have not been well explored. To gain a better understanding of morphine dependence and withdrawal therapy in a model highly related to humans, metabolic changes in brain hippocampus and prefrontal cortex (PFC) of rhesus monkeys were measured by 1H‐nuclear magnetic resonance spectroscopy, coupled with partial least squares and orthogonal signal correction analysis. The results showed that concentrations of myoinositol (M‐Ins) and taurine were significantly reduced, whereas lactic acid was increased in hippocampus and PFC of morphine‐dependent monkeys. Phosphocholine and creatine increased in PFC but decreased in hippocampus after chronic treatment of morphine. Moreover, N‐acetyl aspartate (NAA), γ‐aminobutyric acid, glutamate, glutathione, methionine, and homocysteic acid also changed in these brain regions. These results suggest that chronic morphine exposure causes profound disturbances of neurotransmitters, membrane, and energy metabolism in the brain. Notably, morphine‐induced dysregulations in NAA, creatine, lactic acid, taurine, M‐Ins, and phosphocholine were clearly reversed after intervention with methadone or clonidine. Our study highlights the potential of metabolic profiling to enhance our understanding of metabolite alteration and neurobiological actions associated with morphine addiction and withdrawal therapy in primates. © 2012 Wiley Periodicals, Inc.
Accumulation of autofluorescent storage material in brain is accelerated by ischemia in chloride channel 3 gene‐deficient mice
Authors: Ohtaki Hirokazu , Ohara Kenji , Song Dandan , Miyamoto Kazuyuki , Tsumuraya Tomomi , Yofu Sachiko , Dohi Kenji , Tanabe Shigeru , Sasaki Sei , Uchida Shinichi , Matsunaga Masaji , Shioda Seiji 
Published: July 2012

AbstractAutofluorescent storage material (ASM) is an aging pigment that accumulates during the normal course of senescence. Although the role of ASM has yet to be fully elucidated, ASM has been implicated in age‐related neurodegeneration. In this study, we determined the level of ASM in chloride channel 3 (ClC‐3) gene‐deficient (KO) mice both in response to aging and following mild global ischemia. To understand the mechanism of action of the ASM, mice subjected to ischemia were treated with the cyclooxygenase (COX) inhibitor indomethacin or with the noncompetitive glutamate receptor antagonist MK‐801. ClC‐3 KO mice displayed age‐related neurodegeneration of the neocortex as well as the hippocampus. The cortical layers in particular granular layers became thinner with aging. ASM accumulated in the brains of ClC‐3 KO mice was increased seven‐ to 50‐fold over that observed in the corresponding regions of their wild‐type littermates. Young wild‐type mice survived longer than age‐matched ClC‐3 KO mice after permanent global ischemia. However, in the case of older animals, the survival curves were similar. The ASM also increased four‐ to fivefold 10 days after mild global ischemia, an effect that was suppressed by treatment with indomethacin and MK‐801. These results suggest that temporary ischemia might trigger a process similar to aging in the brain, mimicking the effect of age‐related neurodegenerative diseases. © 2012 Wiley Periodicals, Inc.
Characterization of cellular protective effects of ATP13A2/PARK9 expression and alterations resulting from pathogenic mutants
Authors: Covy Jason P. , Waxman Elisa A. , Giasson Benoit I. 
Published: July 2012

AbstractMutations in ATP13A2, which encodes a lysosomal P‐type ATPase of unknown function, cause an autosomal recessive parkinsonian syndrome. With mammalian cells, we show that ATP13A2 expression protects against manganese and nickel toxicity, in addition to proteasomal, mitochondrial, and oxidative stress. Consistent with a recessive mode of inheritance of gene defects, disease‐causing mutations F182L and G504R are prone to misfolding and do not protect against manganese and nickel toxicity because they are unstable as a result of degradation via the endoplasmic reticulum‐associated degradation (ERAD)‐proteasome system. The protective effects of ATP13A2 expression are not due to inhibition of apoptotic pathways or a reduction in typical stress pathways, insofar as these pathways are still activated in challenged ATP13A2‐expressing cells; however, these cells display a dramatic reduction in the accumulation of oxidized and damaged proteins. These data indicate that, contrary to a previous suggestion, ATP13A2 is unlikely to convey cellular resilience simply by acting as a lysosomal manganese transporter. Consistent with the recent identification of an ATP13A2 recessive mutation in Tibetan terriers that develop neurodegeneration with neuronal ceroid lipofucinoses, our data suggest that ATP13A2 may function to import a cofactor required for the function of a lysosome enzyme(s). © 2012 Wiley Periodicals, Inc.
Surface cross‐linked UHMWPE can enable the use of larger femoral heads in total joints
Authors: Oral Ebru , Neils Andrew L. , Lyons Chelsea , Fung Mitchell , Doshi Brinda , Muratoglu Orhun K. 
Published: July 2012

AbstractLimiting cross‐linking to the articular surfaces of ultrahigh molecular weight polyethylene (UHMWPE) to increase wear resistance while preventing detrimental effects of cross‐linking on mechanical strength has been a desirable goal. A surface cross‐linked UHMWPE can be achieved by blending UHMWPE with a free radical scavenger, such as vitamin E, consolidating the blend into an implant shape, extracting the vitamin E from the surface, and radiation cross‐linking the surface extracted blend. This process results in high cross‐link density in the vitamin E‐depleted surface region because vitamin E hinders cross‐linking during irradiation. In this study, we described the properties of successful extraction media and the manipulation of the wear and mechanical properties of extracted, irradiated blends. We showed that these formulations could have similar wear and significantly improved mechanical properties compared to currently available highly cross‐linked UHMWPEs. We believe that these materials can enable thinner implant forms and more anatomical designs in joint arthroplasty and may provide a feasible alternative to metal‐on‐metal implants. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:59–66, 2012
Eccentric training improves tendon biomechanical properties: A rat model
Authors: Kaux Jean‐François , Drion Pierre , Libertiaux Vincent , Colige Alain , Hoffmann Audrey , Nusgens Betty , Besançon Benoît , Forthomme Bénédicte , Le Goff Caroline , Franzen Rachel , Defraigne Jean‐Olivier , Cescotto Serge , Rickert Markus , Crielaard Jean‐Michel , Croisier Jean‐Louis 
Published: July 2012

AbstractThe treatment of choice for tendinopathies is eccentric reeducation. Although the clinical results appear favorable, the biomechanical changes to the tissue are not yet clear. Even if the mechanotransduction theory is commonly accepted, the physiology of tendons is not clearly understood. We aimed to better define the biomechanical and histological changes that affect healthy tendon after eccentric and concentric training. This study compared the effects of two methods of training (eccentric [E] training and concentric [C] training) with untrained (U) rats. The animals were trained over a period of 5 weeks. The tricipital, patellar, and Achilles tendons were removed, measured and a tensile test until failure was performed. A histological analysis (hematoxylin and eosin and Masson's trichrome stains) was also realized. There was a significant increase in the rupture force of the patellar and tricipital tendons between the U and E groups. The tricipital tendons in the control group presented a significantly smaller cross‐sectional area than the E‐ and C‐trained groups, but none was constated between E and C groups. No significant difference was observed for the mechanical stress between the three groups for all three tendons. Histological studies demonstrated the development of a greater number of blood vessels and a larger quantity of collagen in the E group. The mechanical properties of tendons in rats improve after specific training, especially following eccentric training. Our results partly explained how mechanical loading, especially in eccentric mode, could improve the healing of tendon. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:119–124, 2012
Sequence Position and Side Chain Length Dependence of Charge Pair Interactions in Collagen Triple Helices
Authors: Wei Fang , Fallas Jorge A. , Hartgerink Jeffrey D. 
Published: July 2012

AbstractIn this study, we examine eight ABC heterotrimers whose self‐assembly is directed through electrostatic interactions. Oppositely charged pairs of amino acids, with varying side chain length, were assessed for their ability to stabilize a triple helix. Aspartate‐lysine was found to result in the most thermally stable helix followed by lysine‐glutamate, ornithine‐aspartate, and finally ornithine‐glutamate. When the sequence position of these charged amino acids was reversed from what is normally observed in nature, triple helix stability and compositional purity were significantly reduced. We examine the effect of salt on triple helix stability and observe that increased salt concentration reduces the thermal stability of heterotrimers by an average of 5 °C, but does not disrupt helix assembly. It was also found that some highly positively charged homotrimers can be stabilized in the presence of phosphate anions.