bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of nanomaterials for bone repair and regeneration
Authors: McMahon Rebecca E. , Wang Lina , Skoracki Roman , Mathur Anshu B. 
Published: December 2012

AbstractBone is a nanocomposite composed of organic (mainly collagen) and inorganic (nanocrystalline hydroxyapatite) components, with a hierarchical structure ranging from nano‐ to macroscale. Its functions include providing mechanical support and transmitting physio‐chemical and mechano‐chemical cues. Clinical repair and reconstruction of bone defects has been conducted using autologous and allogeneic tissues and alloplastic materials, with functional limitations. The design and development of biomaterial scaffolds that will replace the form and function of native tissue while promoting regeneration without necrosis or scar formation is a challenging area of research. Nanomaterials and nanocomposites are promising platforms to recapitulate the organization of natural extracellular matrix for the fabrication of functional bone tissues because nanostructure provides a closer approximation to native bone architecture. Nanostructured scaffolds provide structural support for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. Unique properties of nanomaterials, such as increased wettability and surface area, lead to increased protein adsorption when compared with conventional biomaterials. Cell–scaffold interactions at the cell–material nanointerface may be mediated by integrin‐triggered signaling pathways that affect cell behavior. The materials selection and processing techniques can affect the chemical, physical, mechanical, and cellular recognition properties of biomaterials. In this article, we focused on reviewing current fabrication techniques for nanomaterials and nanocomposites, their cell interaction properties and their application in bone tissue engineering and regeneration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
In vitro bioactivity and cytocompatibility properties of spark plasma sintered HA‐Ti composites
Authors: Kumar Alok , Dhara Sharmistha , Biswas Krishanu , Basu Bikramjit 
Published: December 2012

AbstractThe present study reports the results of the detailed in vitro bioactivity and cytocompatibility properties of the hydroxyapatite (HA) and the HA‐titanium (HA‐Ti) composite with varying amount of Ti (5, 10, and 20 wt %), densified using spark plasma sintering process (SPS). Using this technique and tailoring suitable processing parameters, it has been possible to retain both HA and Ti in the sintered ceramics. Importantly, the uniquely designed SPS processing with suitably chosen parameters enables in achieving better mechanical properties, such as higher indentation fracture toughness (∼1.5 MPa m1/2) in HA‐Ti composites compared with HA. X‐ray diffraction and scanning electron microscopic (SEM) observations reveal good bioactivity of the HA‐Ti composites with the formation of thick, flaky, and porous apatite layer when immersed in simulated body fluid at 37°C and pH of 7.4. Atomic absorption spectroscopic analysis of the simulated body fluid solution reveals dynamic changes in Ca+2 ion concentration with more dissolution of Ca+2 ion from the HA‐20Ti composite. However, the measurements with inductively coupled plasma spectrometer do not record dissolution of Ti+4 ions. Transmission electron microscopic analysis indicates weak crystalline nature of the apatite and confirms the formation of fine‐scale apatite crystals. MTT assay, fluorescence, and SEM study demonstrate good cell viability and cell adhesion/proliferation of the Saos ‐2 cells, cultured on the developed composites under standard culture condition, and the difference in cell viability has been discussed in reference to substrate composition and roughness. Overall, HA‐Ti composites exhibit comparable and even better in vitro bioactivity and cytocompatibility properties than HA. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Biological activity of a nanofibrous barrier membrane containing bone morphogenetic protein formed by core‐shell electrospinning as a sustained delivery vehicle
Authors: Zhu Huiyong , Yu Dan , Zhou Ying , Wang Chi , Gao Mengfei , Jiang Hongliang , Wang Huiming 
Published: December 2012

AbstractThis study reports the in vitro and in vivo biological activities of recombinant human bone morphogenetic protein 2 (rhBMP‐2) released from the core‐shell structure of a nanofibrous barrier membrane as a sustained delivery model for bone regeneration. RhBMP‐2 incorporating poly(ethylene glycol) was used as the core, and poly(caprolactone) was used as the shell surrounding the core. To determine its release profiles, the release solution was collected and the amount of rhBMP‐2 was measured by ELlSA at different time points. In vitro rhBMP‐2, released from the delivery system over at least 24 days, reached a stable rate of 500 pg per day and guided bone marrow mesenchymal stem cells (BMMSCs) to express osteogenic genes. The distribution and proliferation of BMMSCs in the nanofibrous barrier membrane was measured by laser confocal scanning microscopy (LCSM) and scanning electron microscopy (SEM). The biological activity of rhBMP‐2 was tested in BMMSC/membrane culture in vitro and in a rabbit calvarium defect model in vivo. Osteogenic genes osteonectin (ON) and core binding factor‐α1 (Cbf‐α1) expression of the BMMSCs cultured on the BMP‐2‐PEG/PCL membrane were significantly higher than those of cells on the PEG/PCL membrane at the late time points using real‐time PCR (p < 0.05). The membranes containing the rhBMP‐2 group exhibited the fastest and most bone formation compared to others in rabbit cranial defect models (p < 0.05). This study revealed that rhBMP‐2 could be incorporated into a core‐shell electrospun membrane, and preserve sustained release capability and biological activity. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Physicochemical and cell biological characterization of PMMA bone cements modified with additives to increase bioactivity
Authors: Wolf‐Brandstetter Cornelia , Roessler Sophie , Storch Sandra , Hempel Ute , Gbureck Uwe , Nies Berthold , Bierbaum Susanne , Scharnweber Dieter 
Published: December 2012

AbstractPolymethylmethacrylate (PMMA) bone cement is the most widely used material in surgery to fix joint replacements in the bone. In this study, we propose a new approach to generate bioactive PMMA surfaces directly at the site of implantation by adding the amphiphilic molecule phosphorylated 2‐hydroxyethylmethacrylate (HEMA‐P) to commercial PMMA bone cement, both with or without addition of 1–5% soluble calcium and carbonate salts. The setting behavior as well as the mechanical properties, the bonding quality at the metal/cement interface, mineral deposition, and cellular response for different cement modifications were investigated in vitro. The addition of HEMA‐P resulted in entirely positive effects with respect to proliferation and differentiation of osteoblast‐like cells (SaOs‐2) and a very tight contact at the metal/cement interface. No detrimental changes of other properties were detected. The additional incorporation of salts provoked an increased deposition of calcium phosphate minerals but no further improvement in SaOs‐2 cell differentiation. A significant decrease in polarization resistance for cements with high salt content (5%) was attributed to debonding between metal and cement. The results suggest an improved clinical performance of PMMA/HEMA‐P composites, which might be further enhanced by small amounts of the soluble salts. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Longitudinal study of vitamin D metabolites after long bone fracture
Authors: Briggs Adam DM , Kuan Valerie , Greiller Claire L , MacLaughlin Beverley D , Ramachandran Manoj , Harris Timothy , Timms Peter M , Venton Timothy R , Vieth Reinhold , Norman Anthony W , Griffiths Christopher J , Martineau Adrian R 
Published: December 2012

ABSTRACT

Animal models suggest a key role for dihydroxylated vitamin D metabolites in fracture healing, as evidenced by increases in serum concentration of 24R,25-dihydroxyvitamin D (24R,25[OH]2D) after long bone fracture. Human studies investigating the kinetics of serum concentrations of 24R,25[OH]2D, 1,25-dihydroxyvitamin D (1,25[OH]2D) and their parent metabolite 25-hydroxyvitamin D (25[OH]D) are lacking. We, therefore, conducted a longitudinal study to determine whether total, free, or bioavailable concentrations of these vitamin D metabolites fluctuate in humans after long bone fracture. Twenty-eight patients with cross-shaft (diaphyseal) long bone fracture presenting to an emergency department in London, UK, were studied. Serum concentrations of 25(OH)D, 24R,25(OH)2D, 1,25(OH)2D, vitamin D binding protein, albumin, and calcium were determined within 48 hours of fracture and again at 1 and 6 weeks postfracture. Concentrations of free and bioavailable vitamin D metabolites were calculated using standard equations. No changes in mean serum concentrations of 25(OH)D or 24R,25(OH)2D were seen at either follow-up time point versus baseline. In contrast, mean serum 1,25(OH)2D concentration declined by 21% over the course of the study, from 68.5 pmol/L at baseline to 54.1 pmol/L at 6 weeks (p &lt; 0.05). This decline was associated with an increase in mean serum corrected calcium concentration, from 2.32 mmol/L at baseline to 2.40 mmol/L at 1 week (p &lt; 0.001) that was maintained at 6 weeks. No changes in free or bioavailable concentrations of any vitamin D metabolite investigated were seen over the course of the study. We conclude that serum 1,25(OH)2D concentration declines after long bone fracture in humans but that the serum 24R,25(OH)2D concentration does not fluctuate. The latter finding contrasts with those of animal models reporting increases in serum 24R,25(OH)2D concentration after long bone fracture.
Encouraging microbial activity in cementitious systems: an emerging frontier in contaminated soil treatment
Authors: Kogbara Reginald B. 
Published: December 2012

AbstractBioremediation is widely accepted as the most effective remediation technology for organic contamination. Nevertheless, it is ineffective for heavy metals, which cannot be degraded, and their immobilisation through pH control achieved with high‐pH cementitious materials is one of very few feasible means of treatment available. However, progress is being made in encouraging microbial activity in cementitious systems, which could provide a single technology that is effective and can be used for simultaneous treatment of organic and metallic contaminants in contaminated soils. This work considers efforts in this direction; the successes achieved and the challenges encountered are described. The utility of relatively low‐pH magnesium phosphate cement(s) and compost in providing a favourable environment for microbes, as well as the capacity of microbes like Saccharomyces cerevisiae and Rhodococcus ruber immobilised in the cement in degrading organics is highlighted. Overall, the findings are promising and are likely to expand the frontiers of bioremediation and stabilisation/solidification technologies for sustainable treatment of contaminated soils and may be extended to other applicable hazardous waste streams. © 2012 Society of Chemical Industry
Rapid start‐up of a sulfidogenic biofilm reactor: overcoming low acetate consumption
Authors: Celis Lourdes B. , Gallegos‐Garcia Marisol , Vidriales Guillermo , Razo‐Flores Elías 
Published: December 2012

AbstractBACKGROUNDSulfate‐reducing fluidized bed reactors represent an alternative for the treatment of wastewaters that contain dissolved metals. However, the low acetate consumption achieved through sulfate reduction affects the organic matter removal efficiency. The aim of this present work was to develop a sulfidogenic biofilm able to consume acetate via sulfate reduction within a short start‐up period (21 days). Three experiments were conducted in a down‐flow fluidized bed reactor with different acetate/lactate proportions in the feed (50/50, 80/20 and 90/10). Reduction of the influent pH from 6.0 to 4.0 was also studied at the higher acetate content.RESULTSOrganic matter oxidation efficiency was similar in the three experiments (∼67%), nonetheless the sulfate reduction rate was higher in the experiments with 80 and 90% acetate in the feed (744 and 730 mg L−1 d−1). Acetate oxidation via sulfate reduction was highest (39% of inlet) at the ratio 90/10, at which the biofilm specific sulfate reducing activity with acetate was 4.3 times higher than that developed at 50/50. Influent pH reduction to 4.0 was not detrimental to acetate consumption via sulfate reduction, which was 56%. Analysis of the biofilm through DGGE found a similar community in the three experiments and the presence of acetotrophic microorganisms affiliated to Desulfobacca acetoxidans.CONCLUSIONSLimiting the substrate (lactate) was an appropriate strategy to enrich acetate‐consuming sulfate reducers and improve the low acetate removal efficiency that sulfate‐reducing reactors face. © 2012 Society of Chemical Industry
Combined linear array high‐ and convex array low‐frequency duplex ultrasonography with or without examination of the ophthalmic artery in the differential diagnosis of occlusion from severe stenosis of internal carotid artery
Authors: Xiong Jian‐Qun , Wang Li , Yu Chen , Shi Yu‐Wen , Li Ying‐Hua 
Published: December 2012

PurposeTo assess the benefits of using a low‐frequency convex probe and detecting ophthalmic artery blood flow for the differential diagnosis of occlusion from severe stenosis of the internal carotid artery (ICA).MethodsA total of 103 patients were enrolled and had three sequential examinations by an experienced sonographer. First, the proximal ICA was examined with a 5.0–7.5‐MHz linear probe. Second, the distal ICA was examined with a 3.5–5.0‐MHz convex probe. Third, the ophthalmic artery (OA) was examined with a 5.0–7.5‐MHz linear probe. Three parallel sets of diagnoses were made based on results from (1) high‐frequency ultrasonography; (2) combined use of high‐ and low‐frequency ultrasonography; and (3) combined use of high‐ and low‐frequency ultrasonography along with OAs examination findings. Efficiencies of the three diagnoses were compared by receiver operating characteristic curves with digital subtraction angiography as the gold standard.ResultsThe second diagnostic approach yielded the highest sensitivity (96.6%) and specificity (94.5%). OA blood flow was reversed in most, but not all, cases of ICA occlusion (27/29). Areas under the receiver operating characteristic curves of the three diagnoses were significantly different (p < 0.05).ConclusionsThe diagnostic performance of combined high‐ and low‐frequency ultrasonography is greater than that of high‐frequency ultrasonography alone. Although OA examination does not increase the diagnostic performance, it provides helpful data for the assessment of hemodynamics and collateral circulation. © 2013 Wiley Periodicals, Inc. J Clin Ultrasound 41:408–414, 2013
Myoanatomy of Myzostoma cirriferum (Annelida, Myzostomida): Implications for the evolution of the myzostomid body plan
Authors: Helm Conrad , Weigert Anne , Mayer Georg , Bleidorn Christoph 
Published: December 2012

AbstractStudies of rare genomic marker systems suggest that Myzostomida are a subgroup of Annelida and phylogenomic analyses indicate an early divergence of this taxon within annelids. However, adult myzostomids show a highly specialized body plan, which lacks typical annelid features, such as external body annulation, coelomic cavities with metanephridia, and segmental ganglia of the nervous system. The putative loss of these features might be due to the parasitic/symbiotic lifestyle of myzostomids associated with echinoderms. In contrast, the larval anatomy and adult locomotory system resemble those of annelids. To clarify whether the myoanatomy of myzostomids reflects their relationship to annelids, we analyzed the distribution of f‐actin, a common component of muscle fibers, in specimens of Myzostoma cirriferum using phalloidin‐rhodamine labeling in conjunction with confocal laser‐scanning microscopy. Our data reveal that the musculature of the myzostomid body comprises an outer circular layer, an inner longitudinal layer, numerous dorsoventral muscles, and prominent muscles of the parapodial complex. These features correspond well with the common organization of the muscular system in Annelida. In contrast to other annelids, however, several elements of the muscular system in M. cirriferum, including the musculature of the body wall, and the parapodial flexor muscles, exhibit radial symmetry overlaying a bilateral body plan. These findings are in line with the annelid affinity of myzostomids and suggest that the apparent partial radial symmetry of M. cirriferum arose secondarily in this species. Based on our data, we provide a scenario on the rearrangements of muscle fibers that might have taken place in the lineage leading to this species. J. Morphol., 2013. © 2012 Wiley Periodicals, Inc.
Automated liver stiffness measurements with magnetic resonance elastography
Authors: Dzyubak Bogdan , Glaser Kevin , Yin Meng , Talwalkar Jayant , Chen Jun , Manduca Armando , Ehman Richard L. 
Published: December 2012

PurposeTo provide a fully automated algorithm for obtaining stiffness measurements from hepatic magnetic resonance elastography (MRE) images that are consistent with measurements performed by expert readers.Materials and MethodsAn initial liver contour was found using an adaptive threshold and expanded using an active contour to select a homogeneous area of the liver. The confidence map generated during the stiffness calculation was used to select a region of reliable wave propagation. The average stiffness within the automatically generated region of interest (ROI) was compared to measurements by two trained readers in a set of 88 clinical test cases ranging from healthy to severely fibrotic.ResultsThe stiffness measurements reported by the readers differed by −6.76% ± 22.8% (95% confidence) and had an intraclass correlation coefficient (ICC) of 0.972 (P < 0.05). The algorithm and the more experienced reader differed by 4.32% ± 14.9 with an ICC of 0.987.ConclusionThe automated algorithm performed reliably, even though MRE acquisitions often have motion artifacts present. The correlation between the automated measurements and those from the trained readers was superior to the correlation between the readers. J. Magn. Reson. Imaging 2013;38:371–379. © 2013 Wiley Periodicals, Inc.
Detection of enterovirus in the thyroid tissue of patients with graves' disease
Authors: Hammerstad Sara Salehi , Tauriainen Sisko , Hyöty Heikki , Paulsen Trond , Norheim Ingrid , Dahl‐Jørgensen Knut 
Published: December 2012

AbstractThe etiology and pathogenesis of Graves' disease (GD) are still unknown, although it is thought that both genetic and environmental factors are important. Some indirect evidence implies that a viral infection may be a possible etiologic factor in autoimmunity. The main objective of this study was to examine direct evidence of the presence of enteroviruses (EVs) in the thyroid tissue of patients with GD. Thyroid tissue from 22 patients with newly diagnosed GD was obtained by core needle biopsy, while tissue from 24 patients with chronic GD and 24 control subjects without any autoimmune thyroid diseases was collected during neck surgery. Formalin‐fixed, paraffin‐embedded thyroid tissue samples were examined for the presence of enterovirus capsid protein using immunohistochemistry and for enterovirus RNA using in situ hybridization. Enterovirus capsid protein was detected in 17 (37%) patients and in 4 (17%) control subjects (P = 0.103). Enterovirus RNA was identified in thyroid tissue from nine (20%) patients, but in none of the control subjects (P = 0.016). Eight (90%) of the nine virus RNA positive patients were also positive for enterovirus protein. This is the first study to analyze thyroid tissue for EVs, including patients with untreated, newly diagnosed GD. The results suggest that EVs are more frequently present in thyroid tissue of patients than controls. Further studies are indicated to explore this association to find out if a low‐grade chronic enteroviral infection might be involved in the pathogenesis of GD and if this could offer new therapeutic and preventive opportunities. J. Med. Virol. 85:512–518, 2013. © 2012 Wiley Periodicals, Inc.
Innovation: Misconceptions, trends, and directions
Authors: Bel Roland 
Published: December 2012

AbstractClose observation of innovative organizations ranging from 3M to Cirque du Soleil sheds light on common principles and philosophies that have spurred their groundbreaking development. To maintain a leading edge, companies must first dispense with a series of myths that have arisen around the topic of innovation. Contrary to popular belief, innovation is taking place in developing countries, and the most successful companies are followers rather than pioneers. Innovative companies know when to kill projects and learn how to exploit the sources of innovation more comprehensively and more efficiently, leveraging technology and ideas coming from universities, suppliers, competitors, users, other industries or customer segments, and employees. The most successful companies foster an innovation‐oriented culture, are customer‐oriented, and become masters of execution. In sum, innovation is a complex process that requires discipline and methodology. © 2013 Wiley Periodicals, Inc.
Moisture Permeation in Liquid Crystalline Epoxy Thermosets
Authors: Nie Lei , Burgess Andrew , Ryan Anthony 
Published: December 2012

AbstractA liquid crystalline thermoset (LCT), 4,4′‐diglycidyloxy‐α‐methylstilbene/sulfanilamide, is studied by dynamic mechanical and vapor sorption measurements. Sub‐Tg transitions are assigned to the specific segmental motions through molecular modeling and used to define the environmental temperatures for the study of water transport properties in LCT. The variation of moisture transport with amine‐epoxy ratio reveals that the crosslink density and local concentration of polar groups play the key role in determining both the diffusivity and solubility. The LCT exhibits much lower water diffusion than analogous isotropic networks while the solubility is essentially the same. Segmental flexibility and an ordered smectic layered structure are responsible for the lower permeability.
Investigation of flax fibre reinforced epoxy friction composites
Authors: Taha I. 
Published: December 2012

AbstractThe use of eco‐materials on the basis of natural fibre reinforced polymer composites has found its way to many applications. In the automobile sector, the use of such composites has long been established for applications in the car interior. The use of natural fibre reinforced composites for braking applications has however not been confirmed yet. In this study the use of flax fibres as a candidate reinforcement substitution for glass or even the carcinogenic asbestos fibres has been investigated. Typical frictional materials such as alumina, iron and brass particulates have been used together with graphite as a lubricant. Epoxy resin was used as the binding matrix. Results show frictional behaviours comparable with commercially available brake linings at acceptable wear rates.