bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydroxyapatite/polylactide biphasic combination scaffold loaded with dexamethasone for bone regeneration
Authors: Son Jun‐Sik , Kim Su‐Gwan , Oh Ji‐Su , Appleford Mark , Oh Sunho , Ong Joo L , Lee Kyu‐Bok 
Published: September 2011

AbstractThis study presents a novel design of a ceramic/polymer biphasic combination scaffold that mimics natural bone structures and is used as a bone graft substitute. To mimic the natural bone structures, the outside cortical‐like shells were composed of porous hydroxyapatite (HA) with a hollow interior using a polymeric template‐coating technique; the inner trabecular‐like core consisted of porous poly(D,L‐lactic acid) (PLA) that was loaded with dexamethasone (DEX) and was directly produced using a particle leaching/gas forming technique to create the inner diameter of the HA scaffold. It was observed that the HA and PLA parts of the fabricated HA/PLA biphasic scaffold contained open and interconnected pore structures, and the boundary between both parts was tightly connected without any gaps. It was found that the structure of the combination scaffold was analogous to that of natural bone based on micro‐computed tomography analysis. Additionally, the dense, uniform apatite layer was formed on the surface of the HA/PLA biphasic scaffold through a biomimetic process, and DEX was successfully released from the PLA of the biphasic scaffold over a 1‐month period. This release caused human embryonic palatal mesenchyme cells to proliferate, differentiate, produce ECM, and form tissue in vitro. Therefore, it was concluded that this functionally graded scaffold is similar to natural bone and represents a potential bone‐substitute material. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Enhancement of the capability of hydroxyapatite formation on Zr with anodic ZrO2 nanotubular arrays via an effective dipping pretreatment
Authors: Wang Lu‐Ning , Adams Alissa , Luo Jing‐Li 
Published: September 2011

AbstractHydroxyapatite (HA) depositions on metallic biomedical implants are widely applied to generate bioactive surfaces in simulated biological environments. Highly ordered anodic ZrO2 nanotubes have attracted increasing interest for biomedical applications. However, previous reports showed that at least 14–28 days were required to obtain HA coating on ZrO2 nanotubular arrays under biomimetic condition, thus capability to grow HA coating on ZrO2 nanotubular at room temperature needs to be enhanced. In the present work, we demonstrate that ZrO2 nanotubular arrays are suitable for an effective dipping treatment to induce more rapid HA coating. A series of ZrO2 nanotubular arrays having different dimensions were fabricated in fluoride containing electrolyte. Then, we used a dipping treatment for biomimetic formation of an adhesive HA coating on the nanotubular arrays. The coatings formed rapidly using this procedure under biomimetic conditions and did not require a high‐temperature annealing process. The as‐formed ZrO2 nanotubular arrays were treated using several dip‐and‐dry steps, through which the nanotubular arrays were filled and covered with calcium phosphate (CaP) nucleation sites. The specimens readily grew HA once immersed in the simulated biological fluid after 2 days immersion. The carbonated HA coating had several micron thickness after 8 days of immersion while only a thin layer of CaP were observed on annealed ZrO2 nanotubes immersed in the same solution for the same duration. Tensile testing showed that bonding strength between HA coating and substrate was 21.6 ± 1.6 MPa. This treatment dramatically improves efficiency for promoting HA formation on anodic ZrO2 nanotubes at room temperature. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Cogrinding significance for calcium carbonate–calcium phosphate mixed cement. II. Effect on cement properties
Authors: Tadier Solène , Bolay Nadine Le , Fullana Sophie Girod , Cazalbou Sophie , Charvillat Cédric , Labarrère Michel , Boitel Daniel , Rey Christian , Combes Christèle 
Published: September 2011

AbstractIn the present study, we aim to evaluate the contribution of the cogrinding process in controlling calcium carbonate‐dicalcium phosphate dihydrate cement properties. We set a method designed to evaluate phase separation, usually occurring during paste extrusion, which is quantitative, reliable, and discriminating and points out the determining role of cogrinding to limit filter‐pressing. We show that solid‐phase cogrinding leads to synergistic positive effects on cement injectability, mechanical properties, and radio‐opacity. It allows maintaining a low (<0.4 kg) and constant load during the extrusion of paste, and the paste's composition remains constant and close to that of the initial paste. Analogous behavior was observed when adding a third component into the solid phase, especially SrCO3 as a contrasting agent. Moreover, the cement's mechanical properties can be enhanced by lowering the L/S ratio because of the lower plastic limit. Finally, unloaded or Sr‐loaded cements show uniform and increased optical density because of the enhanced homogeneity of dry component distribution. Interestingly, this study reveals that cogrinding improves and controls essential cement properties and involves processing parameters that could be easily scaled up. This constitutes a decisive advantage for the development of calcium carbonate‐calcium phosphate mixed cements and, more generally, of injectable multicomponent bone cements that meet a surgeon's requirements. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Phase morphology, physical properties, and biodegradation behavior of novel PLA/PHBHHx blends
Authors: Zhao Qiang , Wang Shufang , Kong Meimei , Geng Weitao , Li Robert K.Y. , Song Cunjiang , Kong Deling 
Published: September 2011

AbstractIn this study, two biodegradable polyesters [i.e., polylactic acid (PLA) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBHHx)] with complementarity in terms of mechanical performance have been combined, and a series of blends with a broad range of compositions has been prepared by thermal compounding. The evolution of phase morphologies with the variation of compositions has been characterized by using Fourier transform infrared spectroscopic imaging together with scanning electron microscope analyses. Thermal, mechanical, and biodegradation properties of the PLA/PHBHHx blends were systematically investigated. Mechanical properties were further analyzed by using theoretical models and correlated with the results of the morphology/structure and compatibility of the blends. Results indicate that PLA/PHBHHx blends are immiscible but can be compatible to some extent at certain compositions (e.g., PLA/PHBHHx (w/w) = 80/20 and 20/80). The physical properties of the blend could be fine tuned by adjusting the blend composition. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Synthesis, characterization of calcium phosphates/polyurethane composites for weight‐bearing implants
Authors: Yoshii Toshitaka , Dumas Jerald E. , Okawa Atsushi , Spengler Dan M. , Guelcher Scott A. 
Published: September 2011

AbstractCalcium phosphate (CaP)/polymer composites have been studied as an alternative graft material for the treatment of bone defects. In this study, lysine‐triisocyanate‐based polyurethane (PUR) composites were synthesized from both hydroxyapatite (HA) and β‐tricalcium phosphate (TCP) to reduce the brittleness of CaP and increase the bioactivity of the polymer. The mechanical properties and in vitro cellular response were investigated for both HA/PUR and TCP/PUR composites. The composites were implanted in femoral defects in rats, and in vivo bioactivity was evaluated by X‐rays, micro‐computed tomography (μCT), and histological sections. In biomechanical testing, PUR improved the mechanical properties of the CaP, thus rendering it potentially suitable for weight‐bearing applications. In vitro cell culture studies showed that CaP/PUR composites are biocompatible, with β‐TCP enhancing the cell viability and proliferation relative to HA. CaP/PUR composites also supported the differentiation of osteoblastic cells on the materials. When implanted in rat femoral defects, the CaP/PUR composites were biocompatible and osteoconductive with no adverse inflammatory response, as evidenced by X‐rays, μCT images, and histological sections. Additionally, a histological examination showed evidence of cellular infiltration and appositional remodeling. These results suggest that CaP/PUR composites could be potentially useful biomaterials for weight‐bearing orthopaedic implants. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Characterization of worn alumina hip replacement prostheses
Authors: Zeng Peng , Rainforth W. Mark. , Inkson Beverley J. , Stewart Todd. D. 
Published: September 2011

AbstractAlumina hip replacement prostheses have been analyzed following in vitro simulated microseparation. The worn surfaces of the alumina acetabular cup and femoral head were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) which identified four different wear zones. Focused ion beam (FIB) cross‐sectioning was used to section the worn surface and produce 3D reconstructions of the subsurface damage. This showed that the subsurface fracture was predominantly intergranular, with occasional intragranular fracture. Significantly, in all cases, fracture was restricted to the outer layer of grains. The wear mechanisms leading to the generation of the stripe wear region on the worn alumina hip prostheses are proposed and microseparation is believed to play a critical role. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Circulating γδ T cells and the risk of acute-phase response after zoledronic acid administration
Authors: Rossini Maurizio , Adami Silvano , Viapiana Ombretta , Ortolani Riccardo , Vella Antonio , Fracassi Elena , Gatti Davide 
Published: September 2011

Abstract
The use of intravenous nitrogen-containing bisphosphonates (N-BPs) is associated with the appearance of an acute phase response (APR) in a proportion of the patients for reasons that are poorly understood. The APR was attributed to the indirect activation of γδ T cells with the release of interferon-γ and tumor necrosis factor (TNF). Forty patients with postmenopausal or senile osteoporosis (age range = 53–91 years) never previously treated with intravenous (iv) bisphosphonate, received a single 5-mg zoledronic acid (ZOL) iv infusion over 15 minutes. White blood cells were counted and analyzed with an automated hematology analyzer (ADVIA 2120i Siemens, New York, USA) and by flow cytometer (BD FACSCanto, Becton Dickinson). The occurrence of APR was defined by the occurrence of fever (&gt;37 °C) during the next 2 days. Forty-two percent of patients (17 of 40) receiving the infusion of ZOL experienced an APR. Compared with the others they were younger (69 ± 7 years versus 74 ± 8 years; p = 0.06), and both the proportion and absolute number of γδ T cells were significant higher (p = 0.02 and p = 0.013, respectively). Nonsignificant differences were found between the two groups for white blood cells and for the other circulating lymphocyte subpopulations. Age was inversely correlated with circulating γδ T cells (p = 0.003) but the difference between the two groups in circulating γδ T cells persisted for age-adjusted values and vice versa. In conclusion, the results of this study indicate that the number of circulating γδ T cells, together with age, are important determinant of the occurrence of APR after intravenous infusion of ZOL and possibly of any other N-BPs. © 2012 American Society for Bone and Mineral Research
A case of hypophosphatemic osteomalacia secondary to deferasirox therapy
Authors: Milat Frances , Wong Phillip , Fuller Peter J , Johnstone Lillian , Kerr Peter G , Doery James CG , Strauss Boyd J , Bowden Donald K 
Published: September 2011

Abstract
Patients with β-thalassemia major require iron-chelation therapy to avoid the complication of iron overload. Until recently, deferoxamine (DFO) was the major iron chelator used in patients requiring chronic hypertransfusion therapy, but DFO required continuous subcutaneous therapy. The availability of deferasirox (Exjade®), an orally active iron chelator, over the past 4 years represented a necessary alternative for patients requiring chelation therapy. However, there have been increasing reports of proximal renal tubular dysfunction and Fanconi Syndrome associated with deferasirox in the literature. We report a case of hypophosphataemic osteomalacia secondary to deferasirox therapy. © 2012 American Society for Bone and Mineral Research
Rare coding variants in ALPL are associated with low serum alkaline phosphatase and low bone mineral density
Authors: Nielson Carrie M , Zmuda Joseph M , Carlos Amy S , Wagoner Wendy J , Larson Emily A , Orwoll Eric S , Klein Robert F 
Published: September 2011

Abstract
Alkaline phosphatase (ALP) plays an essential role in the regulation of tissue mineralization, and its activity is highly heritable. Guided by genetic associations discovered in a murine model, we hypothesized a role for rare coding variants in determining serum ALP level and bone mineral density (BMD) in humans. We sequenced the coding regions of the ALP gene (ALPL) in men with low and normal serum ALP activity levels. Single-nucleotide ALPL variants, including 19 rare nonsynonymous variants (minor allele frequency &lt;1%), were much more frequent among the low ALP group (33.8%) than the normal group (1.4%, p = 1 × 10−11). Within the low ALP group, men with a rare, nonsynonymous variant had 11.2% lower mean serum ALP (p = 3.9 × 10−4), 6.7% lower BMD (p = 0.03), and 11.1% higher serum phosphate (p = 0.002) than those without. In contrast, common nonsynonymous variants had no association with serum ALP, phosphate, or BMD. Multiple rare ALPL coding variants are present in the general population, and nonsynonymous coding variants may be responsible for heritable differences in mineralization and thus BMD. © 2012 American Society for Bone and Mineral Research
A murine model of neurofibromatosis type 1 tibial pseudarthrosis featuring proliferative fibrous tissue and osteoclast-like cells
Authors: El-Hoss Jad , Sullivan Kate , Cheng Tegan , Yu Nicole YC , Bobyn Justin D , Peacock Lauren , Mikulec Kathy , Baldock Paul , Alexander Ian E , Schindeler Aaron , Little David G 
Published: September 2011

Abstract
Neurofibromatosis type 1 (NF1) is a common genetic condition caused by mutations in the NF1 gene. Patients often suffer from tissue-specific lesions associated with local double-inactivation of NF1. In this study, we generated a novel fracture model to investigate the mechanism underlying congenital pseudarthrosis of the tibia (CPT) associated with NF1. We used a Cre-expressing adenovirus (AdCre) to inactivate Nf1 in vitro in cultured osteoprogenitors and osteoblasts, and in vivo in the fracture callus of Nf1flox/flox and Nf1flox/− mice. The effects of the presence of Nf1null cells were extensively examined. Cultured Nf1null-committed osteoprogenitors from neonatal calvaria failed to differentiate and express mature osteoblastic markers, even with recombinant bone morphogenetic protein-2 (rhBMP-2) treatment. Similarly, Nf1null-inducible osteoprogenitors obtained from Nf1 MyoDnull mouse muscle were also unresponsive to rhBMP-2. In both closed and open fracture models in Nf1flox/flox and Nf1flox/− mice, local AdCre injection significantly impaired bone healing, with fracture union being &lt;50% that of wild type controls. No significant difference was seen between Nf1flox/flox and Nf1flox/− mice. Histological analyses showed invasion of the Nf1null fractures by fibrous and highly proliferative tissue. Mean amounts of fibrous tissue were increased upward of 10-fold in Nf1null fractures and bromodeoxyuridine (BrdU) staining in closed fractures showed increased numbers of proliferating cells. In Nf1null fractures, tartrate-resistant acid phosphatase–positive (TRAP+) cells were frequently observed within the fibrous tissue, not lining a bone surface. In summary, we report that local Nf1 deletion in a fracture callus is sufficient to impair bony union and recapitulate histological features of clinical CPT. Cell culture findings support the concept that Nf1 double inactivation impairs early osteoblastic differentiation. This model provides valuable insight into the pathobiology of the disease, and will be helpful for trialing therapeutic compounds. © 2012 American Society for Bone and Mineral Research
Amphiphilic peptides with arginine and valine residues as siRNA carriers
Authors: Ryu Dong‐Wook , Kim Hyun Ah , Ryu Jae Hwan , Lee Dong Yun , Lee Minhyung 
Published: September 2011

AbstractAn efficient and safe delivery carrier is required for the therapeutic application of siRNA. In this research, amphiphilic peptides with arginine and valine residues were evaluated as siRNA carriers. The peptides were composed of 1–4 arginine‐blocks and 6 valine‐blocks. In the aqueous solution, the arginine–valine peptides (RV peptides) formed micelles with hydrophobic cores comprised of a valine block and a cationic surface comprised of an arginine block. In a gel retardation assay, the RV peptides completely retarded siRNA at a 1:10 weight ratio (siRNA:peptide). A heparin competition assay suggested that the RV peptides formed more stable complexes with siRNA than they did with polyethylenimine (25 kDa, PEI25k). In an in vitro silencing assay, a dual luciferase expression (Renilla and firefly luciferases) vector, psiCHECK2, was co‐transfected into human embryonic kidney 293 cells with Renilla‐siRNA using the RV peptides. The specific silencing effect of Renilla luciferase was analyzed in reference to firefly luciferase. The results showed that the R3V6 peptide was more efficient than the R1V6, R2V6, and R4V6 peptides in silencing Renilla luciferase. In the flow cytometry and in vitro silencing studies, the R3V6 peptide delivered Renila‐siRNA as efficiently as PEI25k. The siVEGF/R3V6 peptide also reduced endogenous vascular endothelial growth factor (VEGF) expression in CT27 cells as efficiently as PEI25k. A cytotoxicity assay showed that RV peptides did not cause any cytotoxicity. Therefore, RV peptides may be useful for the development of a safe and efficient delivery carrier of siRNA. J. Cell. Biochem. 113: 619–628, 2012. © 2011 Wiley Periodicals, Inc.
Microarray analysis of 1,25(OH)2D3 regulated gene expression in human primary osteoblasts
Authors: Tarroni Paola , Villa Isabella , Mrak Emanuela , Zolezzi Francesca , Mattioli Michela , Gattuso Claudio , Rubinacci Alessandro 
Published: September 2011

AbstractThough extensive studies have been conducted, questions regarding the molecular effectors and pathways underlying the regulatory role of 1,25(OH)2D3 in human osteoblasts other than cell differentiation and matrix protein production remain unanswered. This study aims to identify genes and pathways that are modulated by 1,25(OH)2D3 treatment in human osteoblasts. Primary osteoblast cultures obtained from human bone tissue samples were treated with 1,25(OH)2D3 (10−7 M) for 24 h and their transcritptomes were profiled by microarray analysis using the Affymetrix GeneChip®. Statistical analysis was conducted to identify genes whose expression is significantly modulated following 1,25(OH)2D3 treatment. One hundred and fifty‐eight genes were found to be differentially expressed. Of these, 136 were upregulated, indicating clear transcriptional activation by 1,25(OH)2D3. Biostatistical evaluation of microarray data by Ingenuity Pathways Analysis (IPA) revealed a relevant modulation of genes involved in vitamin D metabolism (CYP24), immune functions (CD14), neurotransmitter transporters (SLC1A1, SLC22A3), and coagulation [thrombomodulin (THBD), tissue plasminogen activator (PLAT), endothelial protein C receptor (PROCR), thrombin receptor (F2R)]. We identified a restricted number of highly regulated genes and confirmed their differential expression by real‐time quantitative PCR (RT qPCR). The present genome‐wide microarray analysis on 1,25(OH)2D3‐treated human osteoblasts reveals an interplay of critical regulatory and metabolic pathways and supports the hypothesis that 1,25(OH)2D3 can modulate the coagulation process through osteoblasts, activates osteoclastogenesis through inflammation signaling, modulates the effects of monoamines by affecting their reuptake. J. Cell. Biochem. 113: 640–649, 2012. © 2011 Wiley Periodicals, Inc.
Hydrogen abstraction reactions of OH radicals with CH3CH2CH2Cl and CH3CHClCH3: A mechanistic and kinetic study
Authors: Wang Li , Li Yanjie , He Hongqing , Zhang Jinglai 
Published: September 2011

AbstractThe hydrogen abstraction reactions of OH radicals with CH3CH2CH2Cl (R1) and CH3CHClCH3 (R2) have been investigated theoretically by a dual‐level direct dynamics method. The optimized geometries and frequencies of the stationary points are calculated at the B3LYP/6‐311G(d,p) level. To improve the reaction enthalpy and potential barrier of each reaction channel, the single point energy calculation is performed by the BMC‐CCSD method. Using canonical variational transition‐state theory (CVT) with the small‐curvature tunneling correction, the rate constants are evaluated over a wide temperature range of 200–2000 K at the BMC‐CCSD//B3LYP/6‐311G(d,p) level. For the reaction channels with the negative barrier heights, the rate constants are calculated by using the CVT. The calculated total rate constants are consistent with available experimental data. The results show that at lower temperatures, the tunneling correction has an important contribution in the calculation of rate constants for all the reaction channels with the positive barrier heights, while the variational effect is found negligible for some reaction channels. For reactions OH radicals with CH3CH2CH2Cl (R1) and CH3CHClCH3 (R2), the channels of H‐abstraction from –CH2– and –CHCl groups are the major reaction channels, respectively, at lower temperatures. With temperature increasing, contributions from other channels should be taken into account. Finally, the total rate constants are fitted by two models, i.e., three‐parameter and four‐parameter expressions. The enthalpies of formation of the species CH3CHClCH2, CH3CHCH2Cl, and CH2CH2CH2Cl are evaluated by isodesmic reactions. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Electronic structure and low temperature thermoelectric properties of In24 M8 O48 (M = Ge4+, Sn4+, Ti4+, and Zr4+)
Authors: Yan Yu Li , Wang Yuan Xu 
Published: September 2011

AbstractThe electronic structure and transport properties of In24M8O48 (M = Ge4+, Sn4+, Ti4+, and Zr4+) have been studied by using the full‐potential linearized augmented plane‐wave method and the semiclassical Boltzmann theory, respectively. It is found that the magnitude of powerfactor with respect to relation time follows the order of In24Sn8O48 > In24Zr8O48 > In24Ge8O48 > In24Ti8O48. The largest powerfactor is 2.7 × 1012 W/K2ms for In24Sn8O48 at 60 K, which is nearly thirty times larger than those of conventional n‐type thermoelectric materials. The origin of the different thermoelectric behavior for these compounds is discussed from the electronic structure level. It is found that, at low temperature, the dopant strongly affect the bands near the Fermi level, which consequently leads to their different thermoelectric properties. The electronic configuration and the difference in atomic number between the dopant and the host atom also play an important role on the thermoelectric properties of In24M8O48. Our calculations give a valuable insight on how to enhance the thermoelectric performance of In32O48. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011