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Sample records for bone flow-induced mechanotransduction

  1. Biomaterials and bone mechanotransduction

    Science.gov (United States)

    Sikavitsas, V. I.; Temenoff, J. S.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    2001-01-01

    Bone is an extremely complex tissue that provides many essential functions in the body. Bone tissue engineering holds great promise in providing strategies that will result in complete regeneration of bone and restoration of its function. Currently, such strategies include the transplantation of highly porous scaffolds seeded with cells. Prior to transplantation the seeded cells are cultured in vitro in order for the cells to proliferate, differentiate and generate extracellular matrix. Factors that can affect cellular function include the cell-biomaterial interaction, as well as the biochemical and the mechanical environment. To optimize culture conditions, good understanding of these parameters is necessary. The new developments in bone biology, bone cell mechanotransduction, and cell-surface interactions are reviewed here to demonstrate that bone mechanotransduction is strongly influenced by the biomaterial properties.

  2. Bone and skeletal muscle: Key players in mechanotransduction and potential overlapping mechanisms.

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    Goodman, Craig A; Hornberger, Troy A; Robling, Alexander G

    2015-11-01

    The development and maintenance of skeletal muscle and bone mass is critical for movement, health and issues associated with the quality of life. Skeletal muscle and bone mass are regulated by a variety of factors that include changes in mechanical loading. Moreover, bone mass is, in large part, regulated by muscle-derived mechanical forces and thus by changes in muscle mass/strength. A thorough understanding of the cellular mechanism(s) responsible for mechanotransduction in bone and skeletal muscle is essential for the development of effective exercise and pharmaceutical strategies aimed at increasing, and/or preventing the loss of, mass in these tissues. Thus, in this review we will attempt to summarize the current evidence for the major molecular mechanisms involved in mechanotransduction in skeletal muscle and bone. By examining the differences and similarities in mechanotransduction between these two tissues, it is hoped that this review will stimulate new insights and ideas for future research and promote collaboration between bone and muscle biologists.(1). Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Mechanotransduction in cortical bone and the role of piezoelectricity: a numerical approach.

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    Stroe, M C; Crolet, J M; Racila, M

    2013-01-01

    This paper is a contribution to a plausible explanation of the mechanotransduction phenomenon in cortical bone during its remodelling. Our contribution deals only with the mechanical processes and the biological aspects have not been taken into account. It is well known that osteoblasts are able to generate bone in a suitable bony substitute only under fluid action. But the bone created in this manner is not organised to resist specific mechanical stress. Our aim was to suggest the nature of the physical information that can be transmitted - directly or via a biological or biochemical process - to the cell to initiate a cellular activity inducing the reconstruction of the osteon that is best adapted to local mechanical stresses. For this, the cell must have, from our point of view, a good knowledge of its structural environment. But this knowledge exists at the cellular scale while the bone is loaded at the macroscopic scale. This study is based on the SiNuPrOs model that allows exchange of information between the different structural scales of cortical bone. It shows that more than the fluid, the collagen - via its piezoelectric properties - plays an essential role in the transmission of information between the macroscopic and nanoscopic scales. Moreover, this process allows us to explain various dysfunctions and even some diseases.

  4. Force-induced bone growth and adaptation: A system theoretical approach to understanding bone mechanotransduction

    International Nuclear Information System (INIS)

    Maldonado, Solvey; Findeisen, Rolf

    2010-01-01

    The modeling, analysis, and design of treatment therapies for bone disorders based on the paradigm of force-induced bone growth and adaptation is a challenging task. Mathematical models provide, in comparison to clinical, medical and biological approaches an structured alternative framework to understand the concurrent effects of the multiple factors involved in bone remodeling. By now, there are few mathematical models describing the appearing complex interactions. However, the resulting models are complex and difficult to analyze, due to the strong nonlinearities appearing in the equations, the wide range of variability of the states, and the uncertainties in parameters. In this work, we focus on analyzing the effects of changes in model structure and parameters/inputs variations on the overall steady state behavior using systems theoretical methods. Based on an briefly reviewed existing model that describes force-induced bone adaptation, the main objective of this work is to analyze the stationary behavior and to identify plausible treatment targets for remodeling related bone disorders. Identifying plausible targets can help in the development of optimal treatments combining both physical activity and drug-medication. Such treatments help to improve/maintain/restore bone strength, which deteriorates under bone disorder conditions, such as estrogen deficiency.

  5. Mechanotransduction in musculoskeletal tissue regeneration: effects of fluid flow, loading, and cellular-molecular pathways.

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    Qin, Yi-Xian; Hu, Minyi

    2014-01-01

    While mechanotransductive signal is proven essential for tissue regeneration, it is critical to determine specific cellular responses to such mechanical signals and the underlying mechanism. Dynamic fluid flow induced by mechanical loading has been shown to have the potential to regulate bone adaptation and mitigate bone loss. Mechanotransduction pathways are of great interests in elucidating how mechanical signals produce such observed effects, including reduced bone loss, increased bone formation, and osteogenic cell differentiation. The objective of this review is to develop a molecular understanding of the mechanotransduction processes in tissue regeneration, which may provide new insights into bone physiology. We discussed the potential for mechanical loading to induce dynamic bone fluid flow, regulation of bone adaptation, and optimization of stimulation parameters in various loading regimens. The potential for mechanical loading to regulate microcirculation is also discussed. Particularly, attention is allotted to the potential cellular and molecular pathways in response to loading, including osteocytes associated with Wnt signaling, elevation of marrow stem cells, and suppression of adipotic cells, as well as the roles of LRP5 and microRNA. These data and discussions highlight the complex yet highly coordinated process of mechanotransduction in bone tissue regeneration.

  6. Review of cellular mechanotransduction

    Science.gov (United States)

    Wang, Ning

    2017-06-01

    Living cells and tissues experience physical forces and chemical stimuli in the human body. The process of converting mechanical forces into biochemical activities and gene expression is mechanochemical transduction or mechanotransduction. Significant advances have been made in understanding mechanotransduction at the cellular and molecular levels over the last two decades. However, major challenges remain in elucidating how a living cell integrates signals from mechanotransduction with chemical signals to regulate gene expression and to generate coherent biological responses in living tissues in physiological conditions and diseases.

  7. Mechanotransduction through Cytoskeleton

    Science.gov (United States)

    Ingber, Donald

    2002-01-01

    The goal of this project was to characterize the molecular mechanism by which cells recognize and respond to physical forces in their local environment. The project was based on the working hypothesis that cells sense mechanical stresses, such as those due to gravity, through their cell surface adhesion receptors (e.g., integrins) and that they respond as a result of structural arrangements with their internal cytoskeleton (CSK) which are orchestrated through use of tensegrity architecture. In this project, we carried out studies to define the architectural and molecular basis of cellular mechanotransduction. Our major goal was to define the molecular pathway that mediates mechanical force transfer between integrins and the CSK and to determine how mechanical deformation of integrin-CSK linkages is transduced into a biochemical response. Elucidation of the mechanism by which cells sense mechanical stresses through integrins and translate them into a biochemical response should help us to understand the molecular basis of the cellular response to gravity as well as many other forms of mechanosensation and tissue regulation. The specific aims of this proposal were: 1. To define the molecular basis of mechanical coupling between integrins, vinculin, and the actin CSK; 2. To develop a computer simulation of how mechanical stresses alter CSK structure and test this model in living cells; 3. To determine how mechanical deformation of integrin-CSK linkages is transduced into a biochemical response.

  8. Mechanotransductive surfaces for reversible biocatalysis activation

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    Mertz, Damien; Vogt, Cédric; Hemmerlé, Joseph; Mutterer, Jérôme; Ball, Vincent; Voegel, Jean-Claude; Schaaf, Pierre; Lavalle, Philippe

    2009-09-01

    Fibronectin, like other proteins involved in mechanotransduction, has the ability to exhibit recognition sites under mechanical stretch. Such cryptic sites are buried inside the protein structure in the native fold and become exposed under an applied force, thereby activating specific signalling pathways. Here, we report the design of new active polymeric nanoassembled surfaces that show some similarities to these cryptic sites. These nanoassemblies consist of a first polyelectrolyte multilayer stratum loaded with enzymes and capped with a second polyelectrolyte multilayer acting as a mechanically sensitive nanobarrier. The biocatalytic activity of the film is switched on/off reversibly by mechanical stretching, which exposes enzymes through the capping barrier, similarly to mechanisms involved in proteins during mechanotransduction. This first example of a new class of biologically inspired surfaces should have great potential in the design of various devices aimed to trigger and modulate chemical reactions by mechanical action with applications in the field of microfluidic devices or mechanically controlled biopatches for example.

  9. YAP-mediated mechanotransduction in skeletal muscle

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    Martina eFischer

    2016-02-01

    Full Text Available Skeletal muscle is not only translating chemical energy into mechanical work, it is also a highly adaptive and regenerative tissue whose architecture and functionality is determined by its mechanical and physical environment. Processing intra- and extracellular mechanical signaling cues contributes to the regulation of cell growth, survival, migration and differentiation. Yes-associated Protein (YAP, a transcriptional coactivator downstream of the Hippo pathway and its paralogue, the transcriptional co-activator with PDZ-binding motif (TAZ, were recently found to play a key role in mechanotransduction in various tissues including skeletal muscle. Furthermore, YAP/TAZ modulate myogenesis and muscle regeneration and abnormal YAP activity has been reported in muscular dystrophy and rhabdomyosarcoma. Here, we summarize the current knowledge of mechanosensing and -signaling in striated muscle. We highlight the role of YAP signaling and discuss the different routes and hypotheses of its regulation in the context of mechanotransduction.

  10. Control of Mechanotransduction by Molecular Clutch Dynamics.

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    Elosegui-Artola, Alberto; Trepat, Xavier; Roca-Cusachs, Pere

    2018-02-26

    The linkage of cells to their microenvironment is mediated by a series of bonds that dynamically engage and disengage, in what has been conceptualized as the molecular clutch model. Whereas this model has long been employed to describe actin cytoskeleton and cell migration dynamics, it has recently been proposed to also explain mechanotransduction (i.e., the process by which cells convert mechanical signals from their environment into biochemical signals). Here we review the current understanding on how cell dynamics and mechanotransduction are driven by molecular clutch dynamics and its master regulator, the force loading rate. Throughout this Review, we place a specific emphasis on the quantitative prediction of cell response enabled by combined experimental and theoretical approaches. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Mechanotransduction in Endothelial Cells Studied with Fluorescence Imaging

    International Nuclear Information System (INIS)

    Chien Shu

    2011-01-01

    Mechanotransduction involves the conversion of mechanical stimuli to intracellular signaling to modulate gene and protein expressions and hence cellular functions in endothelial cells, thus playing importance roles in the regulation of homeostasis in health and disease. The aim of this paper is to investigate the dynamics of mechanotransduction in endothelial cells by the use of fluorescent resonance energy transfer (FRET) to study the temporal and spatial activation of Src kinase and focal adhesion kinase, both of which play critical roles in many cellular processes. The results have contributed to the elucidation of the roles of these two important signaling molecules and their interactions in mediating mechanotransduction.

  12. Key developments that impacted the field of mechanobiology and mechanotransduction.

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    Wall, Michelle; Butler, David; El Haj, Alicia; Bodle, Josephine C; Loboa, Elizabeth G; Banes, Albert J

    2018-02-01

    Advances in mechanobiology have evolved through insights from multiple disciplines including structural engineering, biomechanics, vascular biology, and orthopaedics. In this paper, we reviewed the impact of key reports related to the study of applied loads on tissues and cells and the resulting signal transduction pathways. We addressed how technology has helped advance the burgeoning field of mechanobiology (over 33,600 publications from 1970 to 2016). We analyzed the impact of critical ideas and then determined how these concepts influenced the mechanobiology field by looking at the citation frequency of these reports as well as tracking how the overall number of citations within the field changed over time. These data allowed us to understand how a key publication, idea, or technology guided or enabled the field. Initial observations of how forces acted on bone and soft tissues stimulated the development of computational solutions defining how forces affect tissue modeling and remodeling. Enabling technologies, such as cell and tissue stretching, compression, and shear stress devices, allowed more researchers to explore how deformation and fluid flow affect cells. Observation of the cell as a tensegrity structure and advanced methods to study genetic regulation in cells further advanced knowledge of specific mechanisms of mechanotransduction. The future of the field will involve developing gene and drug therapies to simulate or augment beneficial load regimens in patients and in mechanically conditioning organs for implantation. Here, we addressed a history of the field, but we limited our discussions to advances in musculoskeletal mechanobiology, primarily in bone, tendon, and ligament tissues. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:605-619, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  13. Calcium's Role in Mechanotransduction during Muscle Development

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    Tatiana Benavides Damm

    2014-01-01

    Full Text Available Mechanotransduction is a process where cells sense their surroundings and convert the physical forces in their environment into an appropriate response. Calcium plays a crucial role in the translation of such forces to biochemical signals that control various biological processes fundamental in muscle development. The mechanical stimulation of muscle cells may for example result from stretch, electric and magnetic stimulation, shear stress, and altered gravity exposure. The response, mainly involving changes in intracellular calcium concentration then leads to a cascade of events by the activation of downstream signaling pathways. The key calcium-dependent pathways described here include the nuclear factor of activated T cells (NFAT and mitogen-activated protein kinase (MAPK activation. The subsequent effects in cellular homeostasis consist of cytoskeletal remodeling, cell cycle progression, growth, differentiation, and apoptosis, all necessary for healthy muscle development, repair, and regeneration. A deregulation from the normal process due to disuse, trauma, or disease can result in a clinical condition such as muscle atrophy, which entails a significant loss of muscle mass. In order to develop therapies against such diseased states, we need to better understand the relevance of calcium signaling and the downstream responses to mechanical forces in skeletal muscle. The purpose of this review is to discuss in detail how diverse mechanical stimuli cause changes in calcium homeostasis by affecting membrane channels and the intracellular stores, which in turn regulate multiple pathways that impart these effects and control the fate of muscle tissue.

  14. Transient bioimpedance monitoring of mechanotransduction in artificial tissue during indentation

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    David Cheneler

    2014-09-01

    Full Text Available Mechanotransduction is of fundamental importance in cell physiology, facilitating sensing in touch and hearing as well as tissue development and wound healing. This study used an impedance sensor to monitor the effective resistance and permittivity of artificial tissues, alginate hydrogel with encapsulated fibroblasts, which were kept viable through the use of a bespoke microfluidic system. The observed transient impedance responses upon the application of identical compressive normal loads differed between acellular hydrogels and hydrogels in which fibroblasts were encapsulated. These differences resulted from changes in the conductivity and permeability of the hydrogel due to the presence of the encapsulated fibroblasts, and transient changes in ion concentrations due to mechanotransduction effects.

  15. Optic flow induced self-tilt perception

    NARCIS (Netherlands)

    Bos, J.E.

    2008-01-01

    Roll optic flow induces illusory self-tilt in humans. As far as the mechanism underlying this visual-vestibular interaction is understood, larger angles of self-tilt are predicted than observed. It is hypothesized that the discrepancy can be explained by idiotropic (i.e., referring to a personal

  16. Activation of G proteins mediates flow-induced prostaglandin E2 production in osteoblasts

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    Reich, K. M.; McAllister, T. N.; Gudi, S.; Frangos, J. A.

    1997-01-01

    Interstitial fluid flow may play a role in load-induced bone remodeling. Previously, we have shown that fluid flow stimulates osteoblast production of cAMP inositol trisphosphate (IP3), and PGE2. Flow-induced increases in cAMP and IP3 were shown to be a result of PG production. Thus, PGE2 production appears to be an important component in fluid flow induced signal transduction. In the present study, we investigated the mechanism of flow-induced PGE2 synthesis. Flow-induced a 20-fold increase in PGE2 production in osteoblasts. Increases were also observed with ALF4-(10mM) (98-fold), an activator of guanidine nucleotide-binding proteins (G proteins), and calcium ionophore A23187 (2 microM) (100-fold) in stationary cells. We then investigated whether flow stimulation is mediated by G proteins and increases in intracellular calcium. Flow-induced PGE2 production was inhibited by the G protein inhibitors GDP beta S (100 microM) and pertussis toxin (1 microgram/ml) by 83% and 72%, respectively. Chelation of extracellular calcium by EGTA (2 mM) and intracellular calcium by quin-2/AM (30 microM) blocked flow stimulation by 87% and 67%, respectively. These results suggest that G proteins and calcium play an important role in mediating mechanochemical signal transduction in osteoblasts.

  17. Mechanotransduction and Growth Factor Signalling to Engineer Cellular Microenvironments.

    Science.gov (United States)

    Cipitria, Amaia; Salmeron-Sanchez, Manuel

    2017-08-01

    Engineering cellular microenvironments involves biochemical factors, the extracellular matrix (ECM) and the interaction with neighbouring cells. This progress report provides a critical overview of key studies that incorporate growth factor (GF) signalling and mechanotransduction into the design of advanced microenvironments. Materials systems have been developed for surface-bound presentation of GFs, either covalently tethered or sequestered through physico-chemical affinity to the matrix, as an alternative to soluble GFs. Furthermore, some materials contain both GF and integrin binding regions and thereby enable synergistic signalling between the two. Mechanotransduction refers to the ability of the cells to sense physical properties of the ECM and to transduce them into biochemical signals. Various aspects of the physics of the ECM, i.e. stiffness, geometry and ligand spacing, as well as time-dependent properties, such as matrix stiffening, degradability, viscoelasticity, surface mobility as well as spatial patterns and gradients of physical cues are discussed. To conclude, various examples illustrate the potential for cooperative signalling of growth factors and the physical properties of the microenvironment for potential applications in regenerative medicine, cancer research and drug testing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Mechanotransduction across the cell surface and through the cytoskeleton

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    Wang, N.; Butler, J. P.; Ingber, D. E.

    1993-01-01

    Mechanical stresses were applied directly to cell surface receptors with a magnetic twisting device. The extracellular matrix receptor, integrin beta 1, induced focal adhesion formation and supported a force-dependent stiffening response, whereas nonadhesion receptors did not. The cytoskeletal stiffness (ratio of stress to strain) increased in direct proportion to the applied stress and required intact microtubules and intermediate filaments as well as microfilaments. Tensegrity models that incorporate mechanically interdependent struts and strings that reorient globally in response to a localized stress mimicked this response. These results suggest that integrins act as mechanoreceptors and transmit mechanical signals to the cytoskeleton. Mechanotransduction, in turn, may be mediated simultaneously at multiple locations inside the cell through force-induced rearrangements within a tensionally integrated cytoskeleton.

  19. Varicose Veins: Role of Mechanotransduction of Venous Hypertension

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    Atta, Hussein M.

    2012-01-01

    Varicose veins affect approximately one-third of the adult population and result in significant psychological, physical, and financial burden. Nevertheless, the molecular pathogenesis of varicose vein formation remains unidentified. Venous hypertension exerted on veins of the lower extremity is considered the principal factor in varicose vein formation. The role of mechanotransduction of the high venous pressure in the pathogenesis of varicose vein formation has not been adequately investigated despite a good progress in understanding the mechanomolecular mechanisms involved in transduction of high blood pressure in the arterial wall. Understanding the nature of the mechanical forces, the mechanosensors and mechanotransducers in the vein wall, and the downstream signaling pathways will provide new molecular targets for the prevention and treatment of varicose veins. This paper summarized the current understanding of mechano-molecular pathways involved in transduction of hemodynamic forces induced by blood pressure and tries to relate this information to setting of venous hypertension in varicose veins. PMID:22489273

  20. Mechanotransduction signaling in podocytes from fluid flow shear stress.

    Science.gov (United States)

    Srivastava, Tarak; Dai, Hongying; Heruth, Daniel P; Alon, Uri S; Garola, Robert E; Zhou, Jianping; Duncan, R Scott; El-Meanawy, Ashraf; McCarthy, Ellen T; Sharma, Ram; Johnson, Mark L; Savin, Virginia J; Sharma, Mukut

    2018-01-01

    Recently, we and others have found that hyperfiltration-associated increase in biomechanical forces, namely, tensile stress and fluid flow shear stress (FFSS), can directly and distinctly alter podocyte structure and function. The ultrafiltrate flow over the major processes and cell body generates FFSS to podocytes. Our previous work suggests that the cyclooxygenase-2 (COX-2)-PGE 2 -PGE 2 receptor 2 (EP2) axis plays an important role in mechanoperception of FFSS in podocytes. To address mechanotransduction of the perceived stimulus through EP2, cultured podocytes were exposed to FFSS (2 dyn/cm 2 ) for 2 h. Total RNA from cells at the end of FFSS treatment, 2-h post-FFSS, and 24-h post-FFSS was used for whole exon array analysis. Differentially regulated genes ( P < 0.01) were analyzed using bioinformatics tools Enrichr and Ingenuity Pathway Analysis to predict pathways/molecules. Candidate pathways were validated using Western blot analysis and then further confirmed to be resulting from a direct effect of PGE 2 on podocytes. Results show that FFSS-induced mechanotransduction as well as exogenous PGE 2 activate the Akt-GSK3β-β-catenin (Ser552) and MAPK/ERK but not the cAMP-PKA signal transduction cascades. These pathways are reportedly associated with FFSS-induced and EP2-mediated signaling in other epithelial cells as well. The current regimen for treating hyperfiltration-mediated injury largely depends on targeting the renin-angiotensin-aldosterone system. The present study identifies specific transduction mechanisms and provides novel information on the direct effect of FFSS on podocytes. These results suggest that targeting EP2-mediated signaling pathways holds therapeutic significance for delaying progression of chronic kidney disease secondary to hyperfiltration.

  1. The impact of flow-induced forces on the morphogenesis of the outflow tract

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    Richard Lance Goodwin

    2014-06-01

    Full Text Available One percent of infants are born with congenital heart disease (CHD, which commonly involves outflow tract (OFT defects. These infants often require complex surgeries, which are associated with long term adverse remodeling effects, and receive replacement valves with limited strength, biocompatibility, and growth capability. To address these problematic issues, researchers have carried out investigations in valve development and valve mechanics. A longstanding hypothesis is that flow-induced forces regulate fibrous valve development, however, the specific mechanisms behind this mechanotransduction remain unclear. The purpose of this study was to implement an in vitro system of outflow tract development to test the response of embryonic OFT tissues to fluid flow. A dynamic, three-dimensional bioreactor system was used to culture embryonic OFT tissue under different levels of flow as well as the absence of flow. In the absence of flow, OFT tissues took on a more primitive phenotype that is characteristic of early OFT cushion development where widely dispersed mesenchymal cells are surrounded by a sparse, disorganized extracellular matrix (ECM. Whereas OFT tissues subjected to physiologically matched flow formed compact mounds of cells, initated,fibrous ECM development, while prolonged supraphysiological flow resulted in abnormal tissue remodeling. This study indicates that both the timing and magnitude of flow alter cellular processes that determine if OFT precursor tissue undergoes normal or pathological development. Specifically, these experiments showed that flow-generated forces regulate the deposition and localization of fibrous ECM proteins, indicating that mechanosensitive signaling pathways are capable of driving pathological OFT development if flows are not ideal.

  2. Osteocytes: mechanosensors of bone and orchestrators of mechanical adaptation

    NARCIS (Netherlands)

    Klein-Nulend, J.; Bakker, A.D.

    2007-01-01

    Significant progress has been made in the field of mechanotransduction in bone cells. The knowledge about the role of osteocytes as the professional mechanosensor cells of bone as well as the lacuno-canalicular porosity as the structure that mediates mechanosensing is increasing. New insights might

  3. Flow mechanotransduction regulates traction forces, intercellular forces, and adherens junctions

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    Ting, Lucas H.; Jahn, Jessica R.; Jung, Joon I.; Shuman, Benjamin R.; Feghhi, Shirin; Han, Sangyoon J.; Rodriguez, Marita L.

    2012-01-01

    Endothelial cells respond to fluid shear stress through mechanotransduction responses that affect their cytoskeleton and cell-cell contacts. Here, endothelial cells were grown as monolayers on arrays of microposts and exposed to laminar or disturbed flow to examine the relationship among traction forces, intercellular forces, and cell-cell junctions. Cells under laminar flow had traction forces that were higher than those under static conditions, whereas cells under disturbed flow had lower traction forces. The response in adhesion junction assembly matched closely with changes in traction forces since adherens junctions were larger in size for laminar flow and smaller for disturbed flow. Treating the cells with calyculin-A to increase myosin phosphorylation and traction forces caused an increase in adherens junction size, whereas Y-27362 cause a decrease in their size. Since tugging forces across cell-cell junctions can promote junctional assembly, we developed a novel approach to measure intercellular forces and found that these forces were higher for laminar flow than for static or disturbed flow. The size of adherens junctions and tight junctions matched closely with intercellular forces for these flow conditions. These results indicate that laminar flow can increase cytoskeletal tension while disturbed flow decreases cytoskeletal tension. Consequently, we found that changes in cytoskeletal tension in response to shear flow conditions can affect intercellular tension, which in turn regulates the assembly of cell-cell junctions. PMID:22447948

  4. Rheological Influence Upon the Glomerular Podocyte and Resultant Mechanotransduction

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    Simona Pichler Sekulic

    2015-03-01

    Full Text Available The glomerular podocyte is exposed to numerous mechanical forces as a constituent of the glomerular filtration apparatus. This includes fluid shear stress (FSS displaced upon the podocytic foot process's apical, lateral, and basal surfaces. Even in the face of continuous flow the podocyte is capable of contributing to physiologic filtration, however with pathologic levels of hyperfiltration there is increased FSS placed upon the cell. The mechanisms by which the podocyte detects and responds to FSS are topics of recent investigations, with the aim to clarify the way these cells are injured and/or adapt in times of hyperfiltration and disease states. As the pathogenesis of numerous glomerulopathies is contingent on the status of the podocyte, understanding the manner that these cells can be modified by FSS is essential. Likewise, determination of the effect of such mechanical forces upon other resident cells of the renal corpuscle would reveal the contribution of FSS in the progression of glomerular diseases. The biochemical manner in which podocytes sense and respond to FSS, that is mechanotransduction, will be discussed.

  5. Flow-induced vibration -- 1994. PVP-Volume 273

    International Nuclear Information System (INIS)

    Au-Yang, M.K.; Fujita, K.

    1994-01-01

    Flow-induced vibration is a subject of practical interest to many engineering disciplines, including the power generation, process, and petrochemical industries. In the nuclear industry, flow-induced vibration reaches a higher level of concern because of safety issues and the huge cost associated with down time and site repair. Not surprisingly, during the last 25 years a tremendous amount of effort has been spent in the study of flow-induced vibration phenomena related to nuclear plant components, notably nuclear steam generator tube banks and nuclear fuel bundles. Yet, in spite of this concentrated effort, the industry is still not free from flow-induced vibration-related problems. This explains why in this volume almost half of the papers address the issue of cross-flow induced vibration in tube bundles, with applications to the nuclear steam generator and nuclear fuel bundles in mind. Unlike 10 or 15 years ago, when flow-induced vibration studies almost always involved experimentation and empirical studies, the advent of high-speed computers has enabled numerical calculation and simulation of this complex phenomenon to take place. Separate abstracts were prepared for 27 papers in this volume

  6. Shear stress modulation of smooth muscle cell marker genes in 2-D and 3-D depends on mechanotransduction by heparan sulfate proteoglycans and ERK1/2.

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    Zhong-Dong Shi

    2010-08-01

    Full Text Available During vascular injury, vascular smooth muscle cells (SMCs and fibroblasts/myofibroblasts (FBs/MFBs are exposed to altered luminal blood flow or transmural interstitial flow. We investigate the effects of these two types of fluid flows on the phenotypes of SMCs and MFBs and the underlying mechanotransduction mechanisms.Exposure to 8 dyn/cm(2 laminar flow shear stress (2-dimensional, 2-D for 15 h significantly reduced expression of alpha-smooth muscle actin (alpha-SMA, smooth muscle protein 22 (SM22, SM myosin heavy chain (SM-MHC, smoothelin, and calponin. Cells suspended in collagen gels were exposed to interstitial flow (1 cmH(2O, approximately 0.05 dyn/cm(2, 3-D, and after 6 h of exposure, expression of SM-MHC, smoothelin, and calponin were significantly reduced, while expression of alpha-SMA and SM22 were markedly enhanced. PD98059 (an ERK1/2 inhibitor and heparinase III (an enzyme to cleave heparan sulfate significantly blocked the effects of laminar flow on gene expression, and also reversed the effects of interstitial flow on SM-MHC, smoothelin, and calponin, but enhanced interstitial flow-induced expression of alpha-SMA and SM22. SMCs and MFBs have similar responses to fluid flow. Silencing ERK1/2 completely blocked the effects of both laminar flow and interstitial flow on SMC marker gene expression. Western blotting showed that both types of flows induced ERK1/2 activation that was inhibited by disruption of heparan sulfate proteoglycans (HSPGs.The results suggest that HSPG-mediated ERK1/2 activation is an important mechanotransduction pathway modulating SMC marker gene expression when SMCs and MFBs are exposed to flow. Fluid flow may be involved in vascular remodeling and lesion formation by affecting phenotypes of vascular wall cells. This study has implications in understanding the flow-related mechanobiology in vascular lesion formation, tumor cell invasion, and stem cell differentiation.

  7. [CHARACTERISTICS OF OSTEOCYTE CELL LINES FROM BONES FORMED AS A RESULT OF MEMBRANOUS (SKULL BONES) AND CHONDRAL (LONG BONES) OSSIFICATION].

    Science.gov (United States)

    Avrunin, A S; Doktorov, A A

    2016-01-01

    The aim of this work was to analyze the literature data and the results of authors' own research, to answer the question--if the osteocytes of bone tissues resulting from membranous and chondral ossification, belong to one or to different cell lines. The differences between the cells of osteocyte lines derived from bones resulting from membranous and chondral ossification were established in: 1) the magnitude of the mechanical signal, initiating the development of the process of mechanotransduction; 2) the nature of the relationship between the magnitude of the mechanical signal that initiates the reorganization of the architecture of bone structures and the resource of their strength; in membranous bones significantly lower mechanical signal caused a substantially greater increment of bone strength resource; 3) the biological activity of bone structures, bone fragments formed from membranous tissue were more optimal for transplantation; 4) the characteristics of expression of functional markers of bone cells at different stages of their differentiation; 5) the nature of the reaction of bone cells to mechanical stress; 6) the sensitivity of bone cells to one of the factors controlling the process of mechanotransduction (PGI2); 7) the functioning of osteocytes during lactation. These differences reflect the functional requirements to the bones of the skeleton--the supporting function in the bones of the limbs and the shaping and protection in the bones of the cranial vault. These data suggest that the results of research conducted on the bones of the skull, should not be transferred to the entire skeleton as a whole.

  8. Scale modeling flow-induced vibrations of reactor components

    International Nuclear Information System (INIS)

    Mulcahy, T.M.

    1982-06-01

    Similitude relationships currently employed in the design of flow-induced vibration scale-model tests of nuclear reactor components are reviewed. Emphasis is given to understanding the origins of the similitude parameters as a basis for discussion of the inevitable distortions which occur in design verification testing of entire reactor systems and in feature testing of individual component designs for the existence of detrimental flow-induced vibration mechanisms. Distortions of similitude parameters made in current test practice are enumerated and selected example tests are described. Also, limitations in the use of specific distortions in model designs are evaluated based on the current understanding of flow-induced vibration mechanisms and structural response

  9. Flow-induced aggregation of colloidal particles in viscoelastic fluids.

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    Xie, Donglin; Qiao, Greg G; Dunstan, Dave E

    2016-08-01

    The flow-induced aggregation of dilute colloidal polystyrene nanoparticles suspended in Newtonian and viscoelastic solutions is reported. A rheo-optical method has been used to detect real-time aggregation processes via measuring optical absorption or scattering in a quartz Couette cell. The observed absorbance decreases over time are attributed to the flow-induced coagulation. Numerical simulations show that the aggregation processes still follow the Smoluchowski coagulation equation in a revised version. Suspensions in a series of media are studied to evaluate the effect of the media rheological properties on the particle aggregation. The data shows that elasticity reduces the aggregation while the solution viscosity enhances the aggregation processes.

  10. Flow induced vibration in shell and tube heat exchangers

    International Nuclear Information System (INIS)

    Soper, B.M.H.

    1981-01-01

    Assessing heat exchanger designs, from the standpoint of flow induced vibration, is becoming increasingly important as shell side flow velocities are increased in a quest for better thermal performance. This paper reviews the state of the art concerning the main sources of vibration excitation, i.e. vortex shedding resonance, turbulent buffeting, fluidelastic instability and acoustic resonance, as well as the structural dynamics of the tubes. It is concluded that there are many areas which require further investigation but there are sufficient data available at present to design, with reasonable confidence, units that will be free from flow induced vibration. Topics which are considered to be key areas for further work are listed

  11. Recent Advances in Magnetic-Nanomaterial-Based Mechanotransduction for Cell Fate Regulation.

    Science.gov (United States)

    Wu, Congyu; Shen, Yajing; Chen, Mengwei; Wang, Kun; Li, Yongyong; Cheng, Yu

    2018-03-15

    Remote control of cells and the regulation of cell events at the molecular level are of great interest in the biomedical field. In addition to chemical compounds and genes, mechanical forces play a pivotal role in regulating cell fate, which have prompted the rapid growth of mechanobiology. From a perspective of nanotechnology, magnetic nanomaterials (MNs) are an appealing option for mechanotransduction due to their capabilities in spatiotemporal manipulation of mechanical forces via the magnetic field. As a newly developed paradigm, magneto-mechanotransduction is harnessed to physically regulate cell fate for biomedical applications. Here, the critical factors that determine the magnetomechanical forces induced by MNs in mechanotransduction are briefly reviewed. Recent innovative approaches and their underlying mechanisms for controlling cell fate are highlighted, which offer possibilities for the remote mechanical manipulation of cells and biomolecules in a precise manner. Promising applications including regenerative medicine and cancer treatment based on magnetomechanical stimulation through MNs are also addressed. Perspectives and challenges in MN-based mechanotransduction are commented. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Analysis of flow induced vibration in heat exchangers

    International Nuclear Information System (INIS)

    Beek, A.W. van

    1977-01-01

    A description will be given of three different types of heat exchangers developed by the Dutch Nuclear Industry Group ''Neratoom'' in cooperation with TNO for the sodium-cooled fast breeder reactor SNR-300 at Kalkar. Moreover, the research related with flow induced vibrations carried out by TNO (Organization for Applied Scientific Research) will be presented. The flow induced forces on the tubes of the straight-tube steam generators were measured at the inlet and outlet section where partial crossflow occurs. With the measured flow induced forces the response of a tube was calculated as a function of the tube-to-supportbush clearances taking into account the non-linear damping effects from the sodium. The theoretical results showed that for this particular design no tube impact damage is to be expected which was confirmed later by a full scale experiment. Special attention will be devoted to the steam generator with helical-coil tube-bundles, where the sodium flows in a counter cross-flow over the tube-bundle. Extensive measurements of the power spectra of the flow induced forces were carried out since no information could be found in the literature. The vibration analysis will be presented and vibration modes of the entire bundle will be compared with experimentally obtained results. Finally a description of the vibration tests to be carried out on the intermediate heat exchanger (IHX) will be presented. (author)

  13. Flow-induced vibrations of circular cylindrical structures

    International Nuclear Information System (INIS)

    Chen, S.

    1977-06-01

    The problems of flow-induced vibrations of circular cylindrical structures are reviewed. First, the general method of analysis and classification of structural responses are presented. Then, the presentation is broken up along the lines with stationary fluid, parallel flow, and cross flow. Finally, design considerations and future research needs are pointed out. 234 references

  14. Flow induced noise modelling for industrial piping systems

    NARCIS (Netherlands)

    Gijrath, H.; Ǎbom, M.

    2003-01-01

    Noise from e.g. gas-transport piping systems becomes more and more a problem for plants located close to urban areas. Too high noise levels are unacceptable and will put limitations on the plant capacity. Flow-induced noise of valves, orifices and headers installed in the installation plays a

  15. Flow-induced vibration of circular cylindrical structures

    International Nuclear Information System (INIS)

    Chen, S.S.

    1985-06-01

    This report summarizes the flow-induced vibration of circular cylinders in quiescent fluid, axial flow, and crossflow, and applications of the analytical methods and experimental data in design evaluation of various system components consisting of circular cylinders. 219 figs., 30 tabs

  16. Specialists meeting on LMFBR flow induced vibrations. Summary report

    International Nuclear Information System (INIS)

    1977-12-01

    A Specialists' Meeting on LMFBR Flow-Induced Vibrations was held at ANL in the United States which was sponsored by the International Atomic Energy Agency (IAEA) on the recommendations of the International Working Group on Fast Reactors (IWGFR). It was attended by participants from France, the Federal Republic of Germany, Italy, Japan, Netherlands, the United Kingdom, the Union of Soviet Socialist Republics, the United States and the IAEA. The purpose of the meeting was to provide, for the first time, a common forum for the exchange of information on flow-induced vibration programs of the member countries. As this was a first meeting, information was sought in the broad areas of: 1. Design Criteria and Problem Areas in LMFBR Design; 2. Current Design Procedures; and 3. Ongoing Research. A session was devoted to each of the above topics wherein papers were presented and discussed followed by open discussions on the session topic. The objective of the open discussions was to identify, from a review of specific reactor designs, (a) flow induced vibration problem areas (expected and observed) and their potential for occurrence; (b) failure modes and associated design criteria; (c) specific components that are susceptible to flow induced vibration; and (d) probable excitation mechanisms. It was aimed to assess the current state-of-the-art in designing to avoid flow induced vibration with consideration of licensing requirements; to evaluate existing methods of analysis, testing, and surveillance, along with their limitations and to identify areas requiring research and review ongoing research programmes relative to these research needs

  17. Flow-Induced Vibration of Circular Cylindrical Structures

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shoei-Sheng [Argonne National Lab. (ANL), Argonne, IL (United States). Components Technology Division

    1985-06-01

    Flow-induced vibration is a term to denote those phenomena associated with the response of structures placed in or conveying fluid flow. More specifically, the terra covers those cases in which an interaction develops between fluid-dynamic forces and the inertia, damping or elastic forces in the structures. The study of these phenomena draws on three disciplines: (1) structural mechanics, (2) mechanical vibration, and (3) fluid dynamics. The vibration of circular cylinders subject to flow has been known to man since ancient times; the vibration of a wire at its natural frequency in response to vortex shedding was known in ancient Greece as aeolian tones. But systematic studies of the problem were not made until a century ago when Strouhal established the relationship between vortex shedding frequency and flow velocity for a given cylinder diameter. The early research in this area has beer summarized by Zdravkovich (1985) and Goldstein (1965). Flow-induced structural vibration has been experienced in numerous fields, including the aerospace industry, power generation/transmission (turbine blades, heat exchanger tubes, nuclear reactor components), civil engineering (bridges, building, smoke stacks), and undersea technology. The problems have usually been encountered or created accidentally through improper design. In most cases, a structural or mechanical component, designed to meet specific objectives, develops problems when the undesired effects of flow field have not been accounted for in the design. When a flow-induced vibration problem is noted in the design stage, the engineer has different options to eliminate the detrimental vibration. Unfortunately, in many situations, the problems occur after the components are already in operation; the "fix" usually is very costly. Flow-induced vibration comprises complex and diverse phenomena; subcritical vibration of nuclear fuel assemblies, galloping of transmission lines, flutter of pipes conveying fluid, and whirling

  18. Flow induced vibrations in liquid metal fast breeder reactors

    International Nuclear Information System (INIS)

    1989-01-01

    Flow induced vibrations are well known phenomena in industry. Engineers have to estimate their destructive effects on structures. In the nuclear industry, flow induced vibrations are assessed early in the design process, and the results are incorporated in the design procedures. In many cases, model testing is used to supplement the design process to ensure that detrimental behaviour due to flow induced vibrations will not occur in the component in question. While these procedures attempt to minimize the probability of adverse performance of the various components, there is a problem in the extrapolation of analytical design techniques and/or model testing to actual plant operation. Therefore, sodium tests or vibrational measurements of components in the reactor system are used to provide additional assurance. This report is a general survey of experimental and calculational methods in this area of structural mechanics. The report is addressed to specialists and institutions in industrialized and developing countries who are responsible for the design and operation of liquid metal fast breeder reactors. 92 refs, 90 figs, 8 tabs

  19. Flow induced vibration studies on PFBR control plug components

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, V., E-mail: prakash@igcar.gov.in [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India); Kumar, P. Anup; Anandaraj, M.; Thirumalai, M.; Anandbabu, C.; Rajan, K.K. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu (India)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Flow induced vibration studies on Prototype Fast Breeder Reactor control plug model carried out. Black-Right-Pointing-Pointer Velocity similitude was followed for the study. Black-Right-Pointing-Pointer Frequencies and amplitude of vibrations of various control plug components measured. Black-Right-Pointing-Pointer Overall values of vibration are well within permissible limits. - Abstract: The construction of Prototype Fast Breeder Reactor (PFBR), a 500 MWe liquid sodium cooled reactor, is in progress at Kalpakkam in India. Control plug (CP) is located right above the core subassemblies in the hot pool. Control plug is an important component as many of the critical reactor parameters are sensed and controlled by the components housed in the control plug assembly. In PFBR primary circuit, components are basically thin walled, slender shells with diameter to thickness ratio ranging from 100 to 650. These components are prone to flow induced vibrations. The existence of free liquid (sodium) surfaces, which is the source of sloshing phenomenon and the operation of primary sodium pump in the primary pool are other potential sources of vibration of reactor components. Control plug is a hollow cylindrical shell structure and provides passages and support for 12 absorber rod drive mechanisms (ARDM) which consists of 9 control and safety rods and 3 diverse safety rods, 210 thermo wells to measure the sodium temperature at the exit of various fuel subassemblies, three failed fuel localization modules (FFLM) and acoustic detectors. It consists of a core cover plate (CCP), which forms the bottom end, two intermediate supports plate, i.e. lower stay plate (LSP) and upper stay plate (USP) and an outer shell. The CCP is located at a distance of 1.3 m from the core top. With such a gap, there will be long free hanging length of the thermocouple sleeves, Delayed neutron detector (DND) sampling tubes and ARDM shroud tubes and hence they are

  20. Nox family NADPH oxidases in mechano-transduction: mechanisms and consequences.

    Science.gov (United States)

    Brandes, Ralf P; Weissmann, Norbert; Schröder, Katrin

    2014-02-20

    The majority of cells in a multi-cellular organism are continuously exposed to ever-changing physical forces. Mechano-transduction links these events to appropriate reactions of the cells involving stimulation of signaling cascades, reorganization of the cytoskeleton and alteration of gene expression. Mechano-transduction alters the cellular redox balance and the formation of reactive oxygen species (ROS). Nicotine amide adenine dinucleotide reduced form (NADPH) oxidases of the Nox family are prominent ROS generators and thus, contribute to this stress-induced ROS formation. Different types and patterns of mechano-stress lead to Nox-dependent ROS formation and Nox-mediated ROS formation contributes to cellular responses and adaptation to physical forces. Thereby, Nox enzymes can mediate vascular protection during physiological mechano-stress. Despite this, over-activation and induction of Nox enzymes and a subsequent substantial increase in ROS formation also promotes oxidative stress in pathological situations like disturbed blood flow or extensive stretch. Individual protein targets of Nox-mediated redox-signaling will be identified to better understand the specificity of Nox-dependent ROS signaling in mechano-transduction. Nox-inhibitors will be tested to reduce cellular activation in response to mechano-stimuli.

  1. Roles of the cytoskeleton, cell adhesion and rho signalling in mechanosensing and mechanotransduction.

    Science.gov (United States)

    Ohashi, Kazumasa; Fujiwara, Sachiko; Mizuno, Kensaku

    2017-03-01

    All cells sense and respond to various mechanical forces in and mechanical properties of their environment. To respond appropriately, cells must be able to sense the location, direction, strength and duration of these forces. Recent progress in mechanobiology has provided a better understanding of the mechanisms of mechanoresponses underlying many cellular and developmental processes. Various roles of mechanoresponses in development and tissue homeostasis have been elucidated, and many molecules involved in mechanotransduction have been identified. However, the whole picture of the functions and molecular mechanisms of mechanotransduction remains to be understood. Recently, novel mechanisms for sensing and transducing mechanical stresses via the cytoskeleton, cell-substrate and cell-cell adhesions and related proteins have been identified. In this review, we outline the roles of the cytoskeleton, cell-substrate and cell-cell adhesions, and related proteins in mechanosensing and mechanotransduction. We also describe the roles and regulation of Rho-family GTPases in mechanoresponses. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  2. Combined effects of flow-induced shear stress and electromagnetic field on neural differentiation of mesenchymal stem cells.

    Science.gov (United States)

    Mascotte-Cruz, Juan Uriel; Ríos, Amelia; Escalante, Bruno

    2016-01-01

    Differentiation of bone marrow-derived mesenchymal stem cells (MSCs) into neural phenotype has been induced by either flow-induced shear stress (FSS) or electromagnetic fields (EMF). However, procedures are still expensive and time consuming. In the present work, induction for 1 h with the combination of both forces showed the presence of the neural precursor nestin as early as 9 h in culture after treatment and this result lasted for the following 6 d. In conclusion, the use of a combination of FSS and EMF for a short-time renders in neurite-like cells, although further investigation is required to analyze cell functionality.

  3. Flow Induced segregation in full scale castings with SCC

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm; Stang, Henrik; Geiker, Mette Rica

    2007-01-01

    Though promising, pioneering work has been carried out with rheological characterization and numerical modelling of form filling with SCC, the approach is far from standard in the concrete industry and clearly the approach does not yet hold all the answers to relevant questions. In particular flow...... induced segregation is a major risk during casting and it is not yet clear how this phenomenon should be modelled. In this paper testing and numerical simulations of full-scale wall castings are compared. Two different SCCs and three different filling methods were applied resulting in different flow...

  4. Flow Induced Vibration Program at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    Argonne National Laboratory has had a Flow Induced Vibration Program since 1967; the Program currently resides in the Laboratory's Components Technology Division. Throughout its existence, the overall objective of the program has been to develop and apply new and/or improved methods of analysis and testing for the design evaluation of nuclear reactor plant components and heat exchange equipment from the standpoint of flow induced vibration. Historically, the majority of the program activities have been funded by the US Atomic Energy Commission (AEC), Energy Research and Development Administration (ERDA), and Department of Energy (DOE). Current DOE funding is from the Breeder Mechanical Component Development Division, Office of Breeder Technology Projects; Energy Conversion and Utilization Technology (ECUT) Program, Office of Energy Systems Research; and Division of Engineering, Mathematical and Geosciences, Office of Basic Energy Sciences. Testing of Clinch River Breeder Reactor upper plenum components has been funded by the Clinch River Breeder Reactor Plant (CRBRP) Project Office. Work has also been performed under contract with Foster Wheeler, General Electric, Duke Power Company, US Nuclear Regulatory Commission, and Westinghouse.

  5. HCN channels are not required for mechanotransduction in sensory hair cells of the mouse inner ear.

    Directory of Open Access Journals (Sweden)

    Geoffrey C Horwitz

    Full Text Available The molecular composition of the hair cell transduction channel has not been identified. Here we explore the novel hypothesis that hair cell transduction channels include HCN subunits. The HCN family of ion channels includes four members, HCN1-4. They were originally identified as the molecular correlates of the hyperpolarization-activated, cyclic nucleotide gated ion channels that carry currents known as If, IQ or Ih. However, based on recent evidence it has been suggested that HCN subunits may also be components of the elusive hair cell transduction channel. To investigate this hypothesis we examined expression of mRNA that encodes HCN1-4 in sensory epithelia of the mouse inner ear, immunolocalization of HCN subunits 1, 2 and 4, uptake of the transduction channel permeable dye, FM1-43 and electrophysiological measurement of mechanotransduction current. Dye uptake and transduction current were assayed in cochlear and vestibular hair cells of wildtype mice exposed to HCN channel blockers or a dominant-negative form of HCN2 that contained a pore mutation and in mutant mice that lacked HCN1, HCN2 or both. We found robust expression of HCNs 1, 2 and 4 but little evidence that localized HCN subunits in hair bundles, the site of mechanotransduction. Although high concentrations of the HCN antagonist, ZD7288, blocked 50-70% of the transduction current, we found no reduction of transduction current in either cochlear or vestibular hair cells of HCN1- or HCN2- deficient mice relative to wild-type mice. Furthermore, mice that lacked both HCN1 and HCN2 also had normal transduction currents. Lastly, we found that mice exposed to the dominant-negative mutant form of HCN2 had normal transduction currents as well. Taken together, the evidence suggests that HCN subunits are not required for mechanotransduction in hair cells of the mouse inner ear.

  6. Flow-Induced Stress Distribution in Porous Scaffolds

    Science.gov (United States)

    Papavassiliou, Dimitrios; Voronov, Roman; Vangordon, Samuel; Sikavitsas, Vassilios

    2010-11-01

    Flow-induced stresses help the differentiation and proliferation of mesenchymal cells cultured in porous scaffolds within perfusion bioreactors. The distribution of stresses in a scaffold is thus important for understanding the tissue growth process in such reactors. Computational results for flow through Poly-L-Lactic Acid porous scaffolds that have been produced with salt-leaching techniques, and for scaffolds that have been constructed with nonwoven fibers, indicate that the probability density function (pdf) of the wall stress, when normalized with the mean and the standard deviation of the pdf, appears to follow a single type of pdf. The scaffolds were imaged with micro-CT and the simulations were run with lattice Boltzmann methods. The parameters of the distribution can be obtained using Darcy's law and the Blake-Kozeny-Carman equation. Experimental results available in the literature appear to corroborate the computational findings, leading to the conclusion that stresses in high-porosity porous materials follow a single distribution.

  7. Review of leakage-flow-induced vibrations of reactor components

    International Nuclear Information System (INIS)

    Mulcahy, T.M.

    1983-05-01

    The primary-coolant flow paths of a reactor system are usually subject to close scrutiny in a design review to identify potential flow-induced vibration sources. However, secondary-flow paths through narrow gaps in component supports, which parallel the primary-flow path, occasionally are the excitation source for significant vibrations even though the secondary-flow rates are orders of magnitude smaller than the primary-flow rate. These so-called leakage flow problems are reviewed here to identify design features and excitation sources that should be avoided. Also, design rules of thumb are formulated that can be employed to guide a design, but quantitative prediction of component response is found to require scale-model testing

  8. Computer modeling of flow induced in-reactor vibrations

    International Nuclear Information System (INIS)

    Turula, P.; Mulcahy, T.M.

    1977-01-01

    An assessment of the reliability of finite element method computer models, as applied to the computation of flow induced vibration response of components used in nuclear reactors, is presented. The prototype under consideration was the Fast Flux Test Facility reactor being constructed for US-ERDA. Data were available from an extensive test program which used a scale model simulating the hydraulic and structural characteristics of the prototype components, subjected to scaled prototypic flow conditions as well as to laboratory shaker excitations. Corresponding analytical solutions of the component vibration problems were obtained using the NASTRAN computer code. Modal analyses and response analyses were performed. The effect of the surrounding fluid was accounted for. Several possible forcing function definitions were considered. Results indicate that modal computations agree well with experimental data. Response amplitude comparisons are good only under conditions favorable to a clear definition of the structural and hydraulic properties affecting the component motion. 20 refs

  9. The role of apical cell-cell junctions and associated cytoskeleton in mechanotransduction.

    Science.gov (United States)

    Sluysmans, Sophie; Vasileva, Ekaterina; Spadaro, Domenica; Shah, Jimit; Rouaud, Florian; Citi, Sandra

    2017-04-01

    Tissues of multicellular organisms are characterised by several types of specialised cell-cell junctions. In vertebrate epithelia and endothelia, tight and adherens junctions (AJ) play critical roles in barrier and adhesion functions, and are connected to the actin and microtubule cytoskeletons. The interaction between junctions and the cytoskeleton is crucial for tissue development and physiology, and is involved in the molecular mechanisms governing cell shape, motility, growth and signalling. The machineries which functionally connect tight and AJ to the cytoskeleton comprise proteins which either bind directly to cytoskeletal filaments, or function as adaptors for regulators of the assembly and function of the cytoskeleton. In the last two decades, specific cytoskeleton-associated junctional molecules have been implicated in mechanotransduction, revealing the existence of multimolecular complexes that can sense mechanical cues and translate them into adaptation to tensile forces and biochemical signals. Here, we summarise the current knowledge about the machineries that link tight and AJ to actin filaments and microtubules, and the molecular basis for mechanotransduction at epithelial and endothelial AJ. © 2017 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  10. Numerical simulation of flow-induced vibrations in tube bundles

    International Nuclear Information System (INIS)

    Elisabeth Longatte; Zaky Bendjeddou; Mhamed Souli

    2005-01-01

    Full text of publication follows: In many industrial components mechanical structures like rod cluster control assembly, fuel assembly and heat exchanger tube bundles are submitted to complex flows causing possible vibrations and damage. Fluid forces are usually split into two parts: structure motion independent forces and fluid-elastic forces coupled with tube motion and responsible for possible dynamic instability development leading to possible short term failures through high amplitude vibrations. Most classical fluid force identification methods rely on structure response experimental measurements associated with convenient data processes. Owing to recent improvements in Computational Fluid Dynamics (C.F.D.), numerical fluid force identification is now practicable in the presence of industrial configurations. The present paper is devoted to numerical simulation of flow-induced vibrations of tube bundles submitted to single-phase cross flows by using C.F.D. codes. Direct Numerical Simulation (D.N.S.), Arbitrary Lagrange Euler formulation (A.L.E.) and code coupling process are involved to predict fluid forces responsible for tube bundle vibrations in the presence of fluid structure and fluid-elastic coupling effects. In the presence of strong multi-physics coupling, simulation of flow-induced vibrations requires a fluid structure code coupling process. The methodology consists in solving in the same time thermohydraulics and mechanics problems by using an A.L.E. formulation for the fluid computation. The purpose is to take into account coupling between flow and structure motions in order to be able to capture coupling effects. From a numerical point of view, there are three steps in the computation: the fluid problem is solved on the computational domain; fluid forces acting on the moving tube are estimated; finally they are introduced in the structure solver providing the tube displacement that is used to actualize the fluid computational domain. Specific

  11. Flow-induced vibration of helical coil compression springs

    International Nuclear Information System (INIS)

    Stokes, F.E.; King, R.A.

    1983-01-01

    Helical coil compression springs are used in some nuclear fuel assembly designs to maintain holddown and to accommodate thermal expansion. In the reactor environment, the springs are exposed to flowing water, elevated temperatures and pressures, and irradiation. Flow parallel to the longitudinal axis of the spring may excite the spring coils and cause vibration. The purpose of this investigation was to determine the flow-induced vibration (FIV) response characteristics of the helical coil compression springs. Experimental tests indicate that a helical coil spring responds like a single circular cylinder in cross-flow. Two FIV excitation mechanisms control spring vibration. Namely: 1) Turbulent Buffeting causes small amplitude vibration which increases as a function of velocity squared. 2) Vortex Shedding causes large amplitude vibration when the spring natural frequency and Strouhal frequency coincide. Several methods can be used to reduce or to prevent vortex shedding large amplitude vibrations. One method is compressing the spring to a coil pitch-to-diameter ratio of 2 thereby suppressing the vibration amplitude. Another involves modifying the spring geometry to alter its stiffness and frequency characteristics. These changes result in separation of the natural and Strouhal frequencies. With an understanding of how springs respond in the flowing water environment, the spring physical parameters can be designed to avoid large amplitude vibration. (orig.)

  12. Rapid flow-induced responses in endothelial cells

    Science.gov (United States)

    Stamatas, G. N.; McIntire, L. V.

    2001-01-01

    Endothelial cells alter their morphology, growth rate, and metabolism in response to fluid shear stress. To study rapid flow-induced responses in the 3D endothelial cell morphology and calcium distribution, coupled fluorescence microscopy with optical sectioning, digital imaging, and numerical deconvolution techniques have been utilized. Results demonstrate that within the first minutes of flow application nuclear calcium is increasing. In the same time frame whole cell height and nuclear height are reduced by about 1 microm. Whole cell height changes may facilitate reduction of shear stress gradients on the luminal surface, whereas nuclear structural changes may be important for modulating endothelial growth rate and metabolism. To study the role of the cytoskeleton in these responses, endothelial cells have been treated with specific disrupters (acrylamide, cytochalasin D, and colchicine) of each of the cytoskeleton elements (intermediate filaments, microfilaments, and microtubules, respectively). None of these compounds had any effect on the shear-induced calcium response. Cytochalasin D and acrylamide did not affect the shear-induced nuclear morphology changes. Colchicine, however, completely abrogated the response, indicating that microtubules may be implicated in force transmission from the plasma membrane to the nucleus. A pedagogical model based on tensegrity theory principles is presented that is consistent with the results on the 3D endothelial morphology.

  13. Flow-induced structured phase in nonionic micellar solutions.

    Science.gov (United States)

    Cardiel, Joshua J; Tonggu, Lige; de la Iglesia, Pablo; Zhao, Ya; Pozzo, Danilo C; Wang, Liguo; Shen, Amy Q

    2013-12-17

    In this work, we consider the flow of a nonionic micellar solution (precursor) through an array of microposts, with focus on its microstructural and rheological evolution. The precursor contains polyoxyethylene(20) sorbitan monooleate (Tween-80) and cosurfactant monolaurin (ML). An irreversible flow-induced structured phase (NI-FISP) emerges after the nonionic precursor flows through the hexagonal micropost arrays, when subjected to strain rates ~10(4) s(-1) and strain ~10(3). NI-FISP consists of close-looped micellar bundles and multiconnected micellar networks as evidenced by transmission electron microscopy (TEM) and cryo-electron microscopy (cryo-EM). We also conduct small-angle neutron scattering (SANS) measurements in both precursor and NI-FISP to illustrate the structural transition. We propose a potential mechanism for the NI-FISP formation that relies on the micropost arrays and the flow kinematics in the microdevice to induce entropic fluctuations in the micellar solution. Finally, we show that the rheological variation from a viscous precursor solution to a viscoelastic micellar structured phase is associated with the structural evolution from the precursor to NI-FISP.

  14. Piezoelectric energy harvesting from flow-induced vibration

    International Nuclear Information System (INIS)

    Wang, D-A; Ko, H-H

    2010-01-01

    A new piezoelectric energy harvester for harnessing energy from flow-induced vibration is developed. It converts flow energy into electrical energy by piezoelectric conversion with oscillation of a piezoelectric film. A finite element model is developed in order to estimate the generated voltage of the piezoelectric laminate subjected to a distributed load. Prototypes of the energy harvester are fabricated and tested. Experimental results show that an open circuit output voltage of 2.2 V pp and an instantaneous output power of 0.2 µW are generated when the excitation pressure oscillates with an amplitude of 1.196 kPa and a frequency of about 26 Hz. The solution of the generated voltage based on the finite element model agrees well with the experiments. Based on the finite element model, the effects of the piezoelectric film dimensions, the fluid pressure applied to the harvester and types of piezoelectric layer on the output voltage of the harvester can be investigated.

  15. Extensional Flow-Induced Dynamic Phase Transitions in Isotactic Polypropylene.

    Science.gov (United States)

    Ju, Jianzhu; Wang, Zhen; Su, Fengmei; Ji, Youxin; Yang, Haoran; Chang, Jiarui; Ali, Sarmad; Li, Xiangyang; Li, Liangbin

    2016-09-01

    With a combination of fast extension rheometer and in situ synchrotron radiation ultra-fast small- and wide-angle X-ray scattering, flow-induced crystallization (FIC) of isotactic polypropylene (iPP) is studied at temperatures below and above the melting point of α crystals (Tmα). A flow phase diagram of iPP is constructed in strain rate-temperature space, composing of melt, non-crystalline shish, α and α&β coexistence regions, based on which the kinetic and dynamic competitions among these four phases are discussed. Above Tmα , imposing strong flow reverses thermodynamic stabilities of the disordered melt and the ordered phases, leading to the occurrence of FIC of β and α crystals as a dynamic phase transition. Either increasing temperature or stain rate favors the competiveness of the metastable β over the stable α crystals, which is attributed to kinetic rate rather than thermodynamic stability. The violent competitions among four phases near the boundary of crystal-melt may frustrate crystallization and result in the non-crystalline shish winning out. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Flow-Induced Crystallization of Poly(ether ether ketone)

    Science.gov (United States)

    Nazari, Behzad; Rhoades, Alicyn; Colby, Ralph

    The effects of an interval of shear above the melting temperature Tm on subsequent isothermal crystallization below Tm is reported for the premier engineering thermoplastic, poly(ether ether ketone) (PEEK). The effect of shear on the crystallization rate of PEEK is investigated by means of rheological techniques and differential scanning calorimetry (DSC) under a protocol of imposing shear in a rotational cone and plate rheometer and monitoring crystallization after quenching. The rate of crystallization at 320 °C was not affected by shear for shear rates <7 s-1 at 350 °C, whereas intervals of adequate shear at higher shear rates prior to the quench to 320 °C accelerated crystallization significantly. As the duration of the interval of shear above 7 s-1 is increased, the crystallization time decreases but at each shear rate eventually saturates once the applied specific work exceeds ~120 MPa. The annealing of the flow-induced precursors was also investigated. The nuclei were fairly persistent at temperatures close to 350 °C, however very unstable at temperatures above 375 °C. This suggests that the nanostructures formed under shear might be akin to crystalline lamellae of greater thickness, compared to quiescently crystallized lamellae.

  17. Flow induced vibrations in arrays of irregularly spaced cylinders

    Science.gov (United States)

    Taub, Gordon; Michelin, Sébastien

    2014-11-01

    Historically the main industrial applications of cylinder arrays in cross flows favored regular arrangements of cylinders. For this reason, most past studies of Flow Induced Vibrations (FIV) in large cylinder arrays have focused on such arrangements. Recently there has been some interest in generating renewable energy using FIV of bluff bodies. In such applications it will likely be beneficial to enhance, rather than suppress FIV. It is not known a priori if regular or irregularly spaced arrays are most adequate for this type of application. In this study, wind tunnel experiments were conducted on one regularly spaced array and four different irregularly spaced arrays of cylinders in a cross flow. Each arrangement of cylinders was examined under eight different orientations to a cross flow ranging between 10 m/s and 17 m/s. The average amplitude of vibration of the cylinders was found to highly depend on arrangement and orientation. The typical amplitude of vibration of the rods in the irregular arrangements were found to be an order of magnitude larger than that of the regular array. A simple model was proposed in order to predict if a given arrangement was likely to produce large oscillations, and the validity of the model was examined. This research was supported by a Marie Curie International Reintegration Grant within the 7th European Community Framework Program (Grant PIRG08-GA-2010-276762).

  18. Multi-scale and multi-physics model of the uterine smooth muscle with mechanotransduction.

    Science.gov (United States)

    Yochum, Maxime; Laforêt, Jérémy; Marque, Catherine

    2018-02-01

    Preterm labor is an important public health problem. However, the efficiency of the uterine muscle during labor is complex and still poorly understood. This work is a first step towards a model of the uterine muscle, including its electrical and mechanical components, to reach a better understanding of the uterus synchronization. This model is proposed to investigate, by simulation, the possible role of mechanotransduction for the global synchronization of the uterus. The electrical diffusion indeed explains the local propagation of contractile activity, while the tissue stretching may play a role in the synchronization of distant parts of the uterine muscle. This work proposes a multi-physics (electrical, mechanical) and multi-scales (cell, tissue, whole uterus) model, which is applied to a realistic uterus 3D mesh. This model includes electrical components at different scales: generation of action potentials at the cell level, electrical diffusion at the tissue level. It then links these electrical events to the mechanical behavior, at the cellular level (via the intracellular calcium concentration), by simulating the force generated by each active cell. It thus computes an estimation of the intra uterine pressure (IUP) by integrating the forces generated by each active cell at the whole uterine level, as well as the stretching of the tissue (by using a viscoelastic law for the behavior of the tissue). It finally includes at the cellular level stretch activated channels (SACs) that permit to create a loop between the mechanical and the electrical behavior (mechanotransduction). The simulation of different activated regions of the uterus, which in this first "proof of concept" case are electrically isolated, permits the activation of inactive regions through the stretching (induced by the electrically active regions) computed at the whole organ scale. This permits us to evidence the role of the mechanotransduction in the global synchronization of the uterus. The

  19. Agrin as a Mechanotransduction Signal Regulating YAP through the Hippo Pathway

    Directory of Open Access Journals (Sweden)

    Sayan Chakraborty

    2017-03-01

    Full Text Available The Hippo pathway effectors YAP and TAZ act as nuclear sensors of mechanical signals in response to extracellular matrix (ECM cues. However, the identity and nature of regulators in the ECM and the precise pathways relaying mechanoresponsive signals into intracellular sensors remain unclear. Here, we uncover a functional link between the ECM proteoglycan Agrin and the transcriptional co-activator YAP. Importantly, Agrin transduces matrix and cellular rigidity signals that enhance stability and mechanoactivity of YAP through the integrin-focal adhesion- and Lrp4/MuSK receptor-mediated signaling pathways. Agrin antagonizes focal adhesion assembly of the core Hippo components by facilitating ILK-PAK1 signaling and negating the functions of Merlin and LATS1/2. We further show that Agrin promotes oncogenesis through YAP-dependent transcription and is clinically relevant in human liver cancer. We propose that Agrin acts as a mechanotransduction signal in the ECM.

  20. The imperative for controlled mechanical stresses in unraveling cellular mechanisms of mechanotransduction

    Directory of Open Access Journals (Sweden)

    Sorkin Adam M

    2006-05-01

    Full Text Available Abstract Background In vitro mechanotransduction studies are designed to elucidate cell behavior in response to a well-defined mechanical signal that is imparted to cultured cells, e.g. through fluid flow. Typically, flow rates are calculated based on a parallel plate flow assumption, to achieve a targeted cellular shear stress. This study evaluates the performance of specific flow/perfusion chambers in imparting the targeted stress at the cellular level. Methods To evaluate how well actual flow chambers meet their target stresses (set for 1 and 10 dyn/cm2 for this study at a cellular level, computational models were developed to calculate flow velocity components and imparted shear stresses for a given pressure gradient. Computational predictions were validated with micro-particle image velocimetry (μPIV experiments. Results Based on these computational and experimental studies, as few as 66% of cells seeded along the midplane of commonly implemented flow/perfusion chambers are subjected to stresses within ±10% of the target stress. In addition, flow velocities and shear stresses imparted through fluid drag vary as a function of location within each chamber. Hence, not only a limited number of cells are exposed to target stress levels within each chamber, but also neighboring cells may experience different flow regimes. Finally, flow regimes are highly dependent on flow chamber geometry, resulting in significant variation in magnitudes and spatial distributions of stress between chambers. Conclusion The results of this study challenge the basic premise of in vitro mechanotransduction studies, i.e. that a controlled flow regime is applied to impart a defined mechanical stimulus to cells. These results also underscore the fact that data from studies in which different chambers are utilized can not be compared, even if the target stress regimes are comparable.

  1. Flow induced/ refined solution crystallization of a semiconducting polymer

    Science.gov (United States)

    Nguyen, Ngoc A.

    Organic photovoltaics, a new generation of solar cells, has gained scientific and economic interests due to the ability of solution-processing and potentially low-cost power production. Though, the low power conversion efficiency of organic/ plastic solar cells is one of the most pertinent challenges that has appealed to research communities from many different fields including materials science and engineering, electrical engineering, chemical engineering, physics and chemistry. This thesis focuses on investigating and controlling the morphology of a semi-conducting, semi-crystalline polymer formed under shear-flow. Molecular structures and processing techniques are critical factors that significantly affect the morphology formation in the plastic solar cells, thus influencing device performance. In this study, flow-induced solution crystallization of poly (3-hexylthiophene) (P3HT) in a poor solvent, 2-ethylnapthalene (2-EN) was utilized to make a paint-like, structural liquid. The polymer crystals observed in this structured paint are micrometers long, nanometers in cross section and have a structure similar to that formed under quiescent conditions. There is pi-pi stacking order along the fibril axis, while polymer chain folding occurs along the fibril width and the order of the side-chain stacking is along fibril height. It was revealed that shear-flow not only induces P3HT crystallization from solution, but also refines and perfects the P3HT crystals. Thus, a general strategy to refine the semiconducting polymer crystals from solution under shear-flow has been developed and employed by simply tuning the processing (shearing) conditions with respect to the dissolution temperature of P3HT in 2-EN. The experimental results demonstrated that shear removes defects and allows more perfect crystals to be formed. There is no glass transition temperature observed in the crystals formed using the flow-induced crystallization indicating a significantly different

  2. Advancements in flow-induced vibration research and design criteria

    International Nuclear Information System (INIS)

    Pettigrew, M.J.

    2009-01-01

    Two-phase flow exists in many nuclear components and, in particular, steam generators. So far relatively little research work has been done on two-phase flow-induced vibration probably because it is difficult to do. Two-phase flows are not homogeneous and are governed by an additional parameter called void fraction. This can lead to different flow patterns or regimes that can change completely the vibration behaviour. Fluidelastic instability, random turbulence excitation and detailed flow characteristics are being investigated in tube bundles subjected to two-phase cross flow. Fluidelastic instability of a tube bundle preferentially flexible in the flow direction was observed probably for the first time. This is particularly relevant to the problem of in-plane vibration of nuclear steam generator U-tubes and has resulted in changes in our design criteria. Unexpected quasi-periodic excitation forces were also measured in the tube bundle. These are attributed to an alternating wake in the lift direction and to fluctuating momentum flux in the drag direction. Vibration damping due to two-phase flow is very dependent on void fraction and appears directly related to the interface surface area between phases. Maximum damping values correspond to the transitions between flow regimes. Fibre optic probes were developed to measure the characteristics of two-phase flows. These probes are used to take detailed measurements in a triangular array of tubes in cross flow. The results show that the flow tends to stream between the tubes. These studies have yielded interesting results but have raised more questions that could lead to improved design criteria. The more puzzling results will be discussed in this presentation. Some of the dynamic phenomena will be illustrated by animation. (author)

  3. Flow-induced vibration in LMFBR steam generators: a state-of-the-art review

    International Nuclear Information System (INIS)

    Shin, Y.S.; Wambsganss, M.W.

    1975-05-01

    This state-of-the-art review identifies and discusses existing methods of flow-induced vibration analysis applicable to steam generators, their limitations, and base-technology needs. Also included are discussions of five different LMFBR steam-generator configurations and important design considerations, failure experiences, possible flow-induced excitation mechanisms, vibration testing, and available methods of vibration analysis. The objectives are to aid LMFBR steam-generator designers in making the best possible evaluation of potential vibration in steam-generator internals, and to provide the basis for development of design guidelines to avoid detrimental flow-induced vibration

  4. Flow-induced vibration and fretting-wear damage in a moisture separator reheater

    International Nuclear Information System (INIS)

    Pettigrew, M.J.; Taylor, C.E.; Fisher, N.J.

    1996-01-01

    Tube failures due to excessive flow-induced vibration were experienced in the tube bundles of moisture separator reheaters in a BWR nuclear station. This paper presents the results of a root cause analysis and covers recommendations for continued operation and for replacement tube bundles. The following tasks are discussed: tube failure analysis; flow velocity distribution calculations; flow-induced vibration analysis with particular emphasis on finned-tubes; fretting-wear testing of a tube and tube-support material combination under simulated operating conditions; field measurements of flow-induced vibration; and development of vibration specifications for replacement tube bundles. The effect of transient operating conditions and of other operational changes such as tube fouling were considered in the analysis. This paper outlines a typical field problem and illustrates the application of flow-induced vibration technology for the solution of a practical problem

  5. Dynamic Characteristics of Flow Induced Vibration in a Rotor-Seal System

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    2011-01-01

    Full Text Available Flow induced vibration is an important factor affecting the performance of the rotor-seal system. From the point of view of flow induced vibration, the nonlinear models of the rotor-seal system are presented for the analysis of the fluid force, which is induced by the interaction between the unstable fluid flow in the seal and the vibrating rotor. The nonlinear characteristics of flow induced vibration in the rotor-seal system are analyzed, and the nonlinear phenomena in the unbalanced rotor-seal system are investigated using the nonlinear models. Various nonlinear phenomena of flow induced vibration in the rotor-seal system, such as synchronization phenomenon and amplitude mutation, are reproduced.

  6. Zyxin Is Involved In Regulation Of Mechanotransduction In Arteriole Smooth Muscle Cells

    Directory of Open Access Journals (Sweden)

    Zhe eSun

    2012-12-01

    Full Text Available Zyxin is a focal adhesion protein that has been implicated in the modulation of cell adhesion and motility, and is hypothesized to be a mechano-sensor in integrin-mediated responses to mechanical force. To test the functional role of zyxin in the mechanotransduction of microvascular smooth muscle cells (VSMC, we utilized atomic force microscopy (AFM to apply localized pulling forces to VSMC through a fibronectin (FN focal adhesion induced by a FN-coated bead on cell surface. Application of force with the AFM induced an increase of zyxin accumulation at the site of the FN-bead focal adhesion that accompanied the VSMC contractile response. Whereas, reduction of zyxin expression by using a zyxin-shRNA construct abolished the VSMC contractile response to AFM pulling forces, even though the zyxin-silenced VSMCs displayed increased adhesion to FN in both AFM adhesion assays and cell adhesion assays. The reduced zyxin expression significantly impaired cell spreading and reorganization of the actin cytoskeleton that could indicate a possible underlying reason for the loss of a contractile response to mechanical force. Consistent with these observations, zyxin silencing also resulted in reduced expression of Rac1, which plays an important role in the actin reorganization in VSMC, but increased TRIP6 and FAK expression, the latter being a major protein that promote cell adhesion. In conclusion, these data support an important enabling role for zyxin in VSMCs ability to mechanically respond to applied force.

  7. Functional Assay of Cancer Cell Invasion Potential Based on Mechanotransduction of Focused Ultrasound

    Directory of Open Access Journals (Sweden)

    Andrew C. Weitz

    2017-08-01

    Full Text Available Cancer cells undergo a number of biophysical changes as they transform from an indolent to an aggressive state. These changes, which include altered mechanical and electrical properties, can reveal important diagnostic information about disease status. Here, we introduce a high-throughput, functional technique for assessing cancer cell invasion potential, which works by probing for the mechanically excitable phenotype exhibited by invasive cancer cells. Cells are labeled with fluorescent calcium dye and imaged during stimulation with low-intensity focused ultrasound, a non-contact mechanical stimulus. We show that cells located at the focus of the stimulus exhibit calcium elevation for invasive prostate (PC-3 and DU-145 and bladder (T24/83 cancer cell lines, but not for non-invasive cell lines (BPH-1, PNT1A, and RT112/84. In invasive cells, ultrasound stimulation initiates a calcium wave that propagates from the cells at the transducer focus to other cells, over distances greater than 1 mm. We demonstrate that this wave is mediated by extracellular signaling molecules and can be abolished through inhibition of transient receptor potential channels and inositol trisphosphate receptors, implicating these proteins in the mechanotransduction process. If validated clinically, our technology could provide a means to assess tumor invasion potential in cytology specimens, which is not currently possible. It may therefore have applications in diseases such as bladder cancer, where cytologic diagnosis of tumor invasion could improve clinical decision-making.

  8. Mechanotransduction-modulated fibrotic microniches reveal the contribution of angiogenesis in liver fibrosis

    Science.gov (United States)

    Liu, Longwei; You, Zhifeng; Yu, Hongsheng; Zhou, Lyu; Zhao, Hui; Yan, Xiaojun; Li, Dulei; Wang, Bingjie; Zhu, Lu; Xu, Yuzhou; Xia, Tie; Shi, Yan; Huang, Chenyu; Hou, Wei; Du, Yanan

    2017-12-01

    The role of pathological angiogenesis on liver fibrogenesis is still unknown. Here, we developed fibrotic microniches (FμNs) that recapitulate the interaction of liver sinusoid endothelial cells (LSECs) and hepatic stellate cells (HSCs). We investigated how the mechanical properties of their substrates affect the formation of capillary-like structures and how they relate to the progression of angiogenesis during liver fibrosis. Differences in cell response in the FμNs were synonymous of the early and late stages of liver fibrosis. The stiffness of the early-stage FμNs was significantly elevated due to condensation of collagen fibrils induced by angiogenesis, and led to activation of HSCs by LSECs. We utilized these FμNs to understand the response to anti-angiogenic drugs, and it was evident that these drugs were effective only for early-stage liver fibrosis in vitro and in an in vivo mouse model of liver fibrosis. Late-stage liver fibrosis was not reversed following treatment with anti-angiogenic drugs but rather with inhibitors of collagen condensation. Our work reveals stage-specific angiogenesis-induced liver fibrogenesis via a previously unrevealed mechanotransduction mechanism which may offer precise intervention strategies targeting stage-specific disease progression.

  9. Investigation on Flow-Induced Noise due to Backflow in Low Specific Speed Centrifugal Pumps

    Directory of Open Access Journals (Sweden)

    Qiaorui Si

    2013-01-01

    Full Text Available Flow-induced noise causes disturbances during the operation of centrifugal pumps and also affects their performance. The pumps often work at off-design conditions, mainly at part-load conditions, because of frequent changes in the pump device system. Consequently numerous unstable phenomena occur. In low specific speed centrifugal pumps the main disturbance is the inlet backflow, which is considered as one of the most important factors of flow-induced noise and vibration. In this study, a test rig of the flow-induced noise and vibration of the centrifugal pump was built to collect signals under various operating conditions. The three-dimensional unsteady flow of centrifugal pumps was calculated based on the Reynolds-averaged equations that resemble the shear stress transport (SST k-ω turbulence model. The results show that the blade passing frequency and shaft frequency are dominant in the spectrum of flow-induced noise, whereas the shaft component, amplitude value at shaft frequency, and peak frequencies around the shaft increase with decreasing flow. Through flow field analysis, the inlet backflow of the impeller occurs under 0.7 times the design flow. The pressure pulsation spectrum with backflow conditions validates the flow-induced noise findings. The velocity characteristics of the backflow zone at the inlet pipe were analyzed, and the dynamic characteristics of the backflow eddy during one impeller rotating period were simultaneously obtained by employing the backflow conditions. A flow visualization experiment was performed to confirm the numerical calculations.

  10. Flow-induced vibration for light water reactors. Program final report

    International Nuclear Information System (INIS)

    Corr, J.E.

    1983-03-01

    The Flow-Induced Vibrations for Light Water Reactors Program was a five-year effort to develop basic knowledge and understanding needed to improve the flow-induced vibration design of light water reactors. Major tasks included analytical and test investigations of the flow-induced vibration of cylinders in isolation and arrays in smooth and turbulent single-vibration testing of reactor components including reactor inlet plenum components, jet pumps, low-pressure coolant injection coupling, and fuel rods. Cases of self-excited limit cycle response were encountered which required design modifications. The fuel rod tests were made in axially flowing water and steam/water mixtures under adiabatic and boiling conditions

  11. Integrity and regeneration of mechanotransduction machinery regulate aminoglycoside entry and sensory cell death.

    Directory of Open Access Journals (Sweden)

    Andrew A Vu

    Full Text Available Sound perception requires functional hair cell mechanotransduction (MET machinery, including the MET channels and tip-link proteins. Prior work showed that uptake of ototoxic aminoglycosides (AG into hair cells requires functional MET channels. In this study, we examined whether tip-link proteins, including Cadherin 23 (Cdh23, regulate AG entry into hair cells. Using time-lapse microscopy on cochlear explants, we found rapid uptake of gentamicin-conjugated Texas Red (GTTR into hair cells from three-day-old Cdh23(+/+ and Cdh23(v2J/+ mice, but failed to detect GTTR uptake in Cdh23(v2J/v2J hair cells. Pre-treatment of wildtype cochleae with the calcium chelator 1,2-bis(o-aminophenoxy ethane-N,N,N',N'-tetraacetic acid (BAPTA to disrupt tip-links also effectively reduced GTTR uptake into hair cells. Both Cdh23(v2J/v2J and BAPTA-treated hair cells were protected from degeneration caused by gentamicin. Six hours after BAPTA treatment, GTTR uptake remained reduced in comparison to controls; by 24 hours, drug uptake was comparable between untreated and BAPTA-treated hair cells, which again became susceptible to cell death induced by gentamicin. Together, these results provide genetic and pharmacologic evidence that tip-links are required for AG uptake and toxicity in hair cells. Because tip-links can spontaneously regenerate, their temporary breakage offers a limited time window when hair cells are protected from AG toxicity.

  12. Pannexin 1 channels play essential roles in urothelial mechanotransduction and intercellular signaling.

    Directory of Open Access Journals (Sweden)

    Hiromitsu Negoro

    Full Text Available Urothelial cells respond to bladder distension with ATP release, and ATP signaling within the bladder and from the bladder to the CNS is essential for proper bladder function. In other cell types, pannexin 1 (Panx1 channels provide a pathway for mechanically-induced ATP efflux and for ATP-induced ATP release through interaction with P2X7 receptors (P2X7Rs. We report that Panx1 and P2X7R are functionally expressed in the bladder mucosa and in immortalized human urothelial cells (TRT-HU1, and participate in urothelial ATP release and signaling. ATP release from isolated rat bladders induced by distention was reduced by the Panx1 channel blocker mefloquine (MFQ and was blunted in mice lacking Panx1 or P2X7R expression. Hypoosmotic shock induced YoPro dye uptake was inhibited by MFQ and the P2X7R blocker A438079 in TRT-HU1 cells, and was also blunted in primary urothelial cells derived from mice lacking Panx1 or P2X7R expression. Rinsing-induced mechanical stimulation of TRT-HU1 cells triggered ATP release, which was reduced by MFQ and potentiated in low divalent cation solution (LDPBS, a condition known to enhance P2X7R activation. ATP signaling evaluated as intercellular Ca2+ wave radius was significantly larger in LDPBS, reduced by MFQ and by apyrase (ATP scavenger. These findings indicate that Panx1 participates in urothelial mechanotransduction and signaling by providing a direct pathway for mechanically-induced ATP release and by functionally interacting with P2X7Rs.

  13. Structural features of the αβTCR mechanotransduction apparatus that promote pMHC discrimination

    Directory of Open Access Journals (Sweden)

    Kristine N Brazin

    2015-09-01

    Full Text Available The αβTCR was recently revealed to function as a mechanoreceptor. That is, it leverages mechanical energy generated during immune surveillance and at the immunological synapse to drive biochemical signaling following ligation by a specific foreign peptide-MHC complex (pMHC. Here we review the structural features that optimize this transmembrane receptor for mechanotransduction. Specialized adaptations include: 1 the CβFG loop region positioned between Vβ and Cβ domains that allosterically gates both dynamic TCR-pMHC bond formation and lifetime; 2 the rigid super β-sheet amalgams of heterodimeric CD3εγ as well as CD3εδ ectodomain components of the αβTCR complex; 3 the αβTCR subunit connecting peptides (CP linking the extracellular and transmembrane (TM segments, particularly the oxidized CxxC motif in each CD3 heterodimeric subunit that facilitates force transfer through the TM segments and surrounding lipid, impacting cytoplasmic tail conformation; and 4 quaternary changes in the αβTCR complex that accompany pMHC ligation under load. How bioforces foster specific αβTCR-based pMHC discrimination and why dynamic bond formation is a primary basis for kinetic proofreading are discussed. We suggest that the details of the molecular rearrangements of individual αβTCR subunit components can be analyzed utilizing a combination of structural biology, single molecule FRET, optical tweezers and nanobiology, guided by insightful atomistic molecular dynamic studies. Finally, we review very recent data showing that the preTCR complex employs a similar mechanobiology to that of the αβTCR to interact with self-pMHC ligands, impacting early thymic repertoire selection prior to the CD4+CD8+ double positive thymocyte stage of development.

  14. Cellular and molecular mechanisms for the bone response to mechanical loading

    Science.gov (United States)

    Bloomfield, S. A.

    2001-01-01

    To define the cellular and molecular mechanisms for the osteogenic response of bone to increased loading, several key steps must be defined: sensing of the mechanical signal by cells in bone, transduction of the mechanical signal to a biochemical one, and transmission of that biochemical signal to effector cells. Osteocytes are likely to serve as sensors of loading, probably via interstitial fluid flow produced during loading. Evidence is presented for the role of integrins, the cell's actin cytoskeleton, G proteins, and various intracellular signaling pathways in transducing that mechanical signal to a biochemical one. Nitric oxide, prostaglandins, and insulin-like growth factors all play important roles in these pathways. There is growing evidence for modulation of these mechanotransduction steps by endocrine factors, particularly parathyroid hormone and estrogen. The efficiency of this process is also impaired in the aged animal, yet what remains undefined is at what step mechanotransduction is affected.

  15. Proteomic Dissection of Nanotopography-Sensitive Mechanotransductive Signaling Hubs that Foster Neuronal Differentiation in PC12 Cells

    Directory of Open Access Journals (Sweden)

    Elisa Maffioli

    2018-01-01

    Full Text Available Neuronal cells are competent in precisely sensing nanotopographical features of their microenvironment. The perceived microenvironmental information will be “interpreted” by mechanotransductive processes and impacts on neuronal functioning and differentiation. Attempts to influence neuronal differentiation by engineering substrates that mimic appropriate extracellular matrix (ECM topographies are hampered by the fact that profound details of mechanosensing/-transduction complexity remain elusive. Introducing omics methods into these biomaterial approaches has the potential to provide a deeper insight into the molecular processes and signaling cascades underlying mechanosensing/-transduction but their exigence in cellular material is often opposed by technical limitations of major substrate top-down fabrication methods. Supersonic cluster beam deposition (SCBD allows instead the bottom-up fabrication of nanostructured substrates over large areas characterized by a quantitatively controllable ECM-like nanoroughness that has been recently shown to foster neuron differentiation and maturation. Exploiting this capacity of SCBD, we challenged mechanosensing/-transduction and differentiative behavior of neuron-like PC12 cells with diverse nanotopographies and/or changes of their biomechanical status, and analyzed their phosphoproteomic profiles in these settings. Versatile proteins that can be associated to significant processes along the mechanotransductive signal sequence, i.e., cell/cell interaction, glycocalyx and ECM, membrane/f-actin linkage and integrin activation, cell/substrate interaction, integrin adhesion complex, actomyosin organization/cellular mechanics, nuclear organization, and transcriptional regulation, were affected. The phosphoproteomic data suggested furthermore an involvement of ILK, mTOR, Wnt, and calcium signaling in these nanotopography- and/or cell mechanics-related processes. Altogether, potential nanotopography

  16. Proteomic Dissection of Nanotopography-Sensitive Mechanotransductive Signaling Hubs that Foster Neuronal Differentiation in PC12 Cells.

    Science.gov (United States)

    Maffioli, Elisa; Schulte, Carsten; Nonnis, Simona; Grassi Scalvini, Francesca; Piazzoni, Claudio; Lenardi, Cristina; Negri, Armando; Milani, Paolo; Tedeschi, Gabriella

    2017-01-01

    Neuronal cells are competent in precisely sensing nanotopographical features of their microenvironment. The perceived microenvironmental information will be "interpreted" by mechanotransductive processes and impacts on neuronal functioning and differentiation. Attempts to influence neuronal differentiation by engineering substrates that mimic appropriate extracellular matrix (ECM) topographies are hampered by the fact that profound details of mechanosensing/-transduction complexity remain elusive. Introducing omics methods into these biomaterial approaches has the potential to provide a deeper insight into the molecular processes and signaling cascades underlying mechanosensing/-transduction but their exigence in cellular material is often opposed by technical limitations of major substrate top-down fabrication methods. Supersonic cluster beam deposition (SCBD) allows instead the bottom-up fabrication of nanostructured substrates over large areas characterized by a quantitatively controllable ECM-like nanoroughness that has been recently shown to foster neuron differentiation and maturation. Exploiting this capacity of SCBD, we challenged mechanosensing/-transduction and differentiative behavior of neuron-like PC12 cells with diverse nanotopographies and/or changes of their biomechanical status, and analyzed their phosphoproteomic profiles in these settings. Versatile proteins that can be associated to significant processes along the mechanotransductive signal sequence, i.e., cell/cell interaction, glycocalyx and ECM, membrane/f-actin linkage and integrin activation, cell/substrate interaction, integrin adhesion complex, actomyosin organization/cellular mechanics, nuclear organization, and transcriptional regulation, were affected. The phosphoproteomic data suggested furthermore an involvement of ILK, mTOR, Wnt, and calcium signaling in these nanotopography- and/or cell mechanics-related processes. Altogether, potential nanotopography-sensitive mechanotransductive

  17. Nitrogen doping effect on flow-induced voltage generation from graphene-water interface

    Science.gov (United States)

    Okada, Takeru; Kalita, Golap; Tanemura, Masaki; Yamashita, Ichiro; Meyyappan, M.; Samukawa, Seiji

    2018-01-01

    Liquid-flow-induced generation of electricity using nanocarbons, particularly graphene-water interface, has received attention for energy harvesting. Here, we have obtained voltage generation from a single water droplet motion on graphene. We have investigated the effect of the graphene surface condition on flow-induced voltage generation, which is controlled by heteroatom doping. Nitrogen-doped graphene shows three times higher voltage generation compared to pristine graphene due to the doping-induced surface charge of graphene. Graphene surface potential tuning by doping is shown to play an important role in voltage generation.

  18. Flow-induced vibration analysis of heat exchanger and steam generator designs

    International Nuclear Information System (INIS)

    Pettigrew, M.J.; Sylvestre, Y.; Campagna, A.O.

    1977-08-01

    Tube and shell heat exchange components such as steam generators, heat exchangers and condensers are essential parts of CANDU nuclear power stations. Excessive flow-induced vibration may cause tube failures by fatigue or more likely by fretting-wear. Such failures may lead to station shutdowns that are very undesirable in terms of lost production. Hence good performance and reliability dictate a thorough flow-induced vibration analysis at the design stage. This paper presents our approach and techniques in this respect. (author)

  19. Exceptional high Seebeck coefficient and gas-flow-induced voltage in multilayer graphene

    Science.gov (United States)

    Li, Xuemei; Yin, Jun; Zhou, Jianxin; Wang, Qin; Guo, Wanlin

    2012-04-01

    Seebeck coefficient of graphene is an important parameter for defining its thermoelectric performance and thus practical applications, such as gas-flow-induced voltage. Here, we find a unique layer-dependence of the graphene Seebeck coefficient that exceptionally increases with increasing thickness to reach a peak value at six layers that is ˜77% higher than monolayer and ˜296% higher than graphite, unlike the monotonic decrease in electric resistance. However, the gas flow-induced voltage is significantly higher in 2, 4, 5, 6, and 7 layered graphene samples than in 1, 3, and 8 layered ones, against the prevailing wisdom that it should be proportional to Seebeck coefficient.

  20. The origin of flow-induced alignment of spherical colloids in shear-thinning viscoelastic fluids

    NARCIS (Netherlands)

    Santos de Oliveira, I.S.; den Otter, Wouter K.; Briels, Willem J.

    2012-01-01

    We have studied the poorly understood process of flow-induced structure formation by colloids suspended in shear-thinning fluids. These viscoelastic fluids contain long flexible chains whose entanglements appear and disappear continuously as a result of Brownian motion and the applied shear flow.

  1. Flow-induced pulsations in closed side branches with wet gas

    NARCIS (Netherlands)

    Sanna, F.; Golliard, J.

    2014-01-01

    In a recent paper it has been shown that the presence of liquid has an influence on Flow Induced Pulsations (FIPs) in closed side branches. Even larger effects of liquid in case of whistling in corrugated pipes were reported. For this experimental study, the “Tandem configuration” with two closed

  2. Flow-induced coalescence: arbitrarily mobile interface model and choice of its parameters

    Czech Academy of Sciences Publication Activity Database

    Fortelný, Ivan; Jůza, Josef

    2015-01-01

    Roč. 60, č. 10 (2015), s. 628-635 ISSN 0032-2725 R&D Projects: GA ČR GAP106/11/1069 Institutional support: RVO:61389013 Keywords : flow-induced coalescence * polymer blends * interface mobility Subject RIV: BK - Fluid Dynamics Impact factor: 0.718, year: 2015

  3. Mechanistic constitutive model for wormlike micelle solutions with flow-induced structure formation

    Science.gov (United States)

    Dutta, Sarit; Graham, Michael

    2017-11-01

    We present a tensor constitutive model for stress and flow-induced structure formation in dilute wormlike micellar solutions. The fluid is treated as a dilute suspension of rigid Brownian rods whose length varies dynamically. Consistent with the mechanism of Turner and Cates, flow-induced alignment of the rods is assumed to promote increase of rod length that corresponds to the formation of flow-induced structures observed in experiments. At very high deformation rate, hydrodynamic stresses cause the rod length to decrease. These mechanisms are implemented in a phenomenological equation governing the evolution of rod length, with the number density of rods appropriately modified to ensure conservation of surfactant mass. The model leads first to an increase in both shear and extensional viscosity as deformation rate increases and then to a decrease at higher rates. If the rate constant for flow-induced rod growth is sufficiently large, the model predicts a multivalued relation between stress and deformation rate in both shear and uniaxial extension in agreement with experimental results. By design, the model is simple enough to serve as a tractable constitutive relation for computational fluid dynamics studies.

  4. Modeling of interface mobility in the description of flow-induced coalescence in immiscible polymer blends

    Czech Academy of Sciences Publication Activity Database

    Fortelný, Ivan; Jůza, Josef

    2013-01-01

    Roč. 291, č. 8 (2013), s. 1863-1870 ISSN 0303-402X R&D Projects: GA ČR GAP106/11/1069 Institutional support: RVO:61389013 Keywords : flow-induced coalescence * polymer blends * matrix drainage Subject RIV: BK - Fluid Dynamics Impact factor: 2.410, year: 2013

  5. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  6. A novel concept of measuring mass flow rates using flow induced ...

    Indian Academy of Sciences (India)

    industry (for supply of catalyst to a reaction). In the present work, a new concept for direct measurement of mass flow rates which does not depend on the volumetric flow rate measurement and obviates the need for the knowledge of density is proposed from the measurement of the flow induced stresses in a substrate.

  7. Flow induced vibration of subsea gas production systems caused by choke valves

    NARCIS (Netherlands)

    Ligterink, N.E.; Groot, R. de; Gharaibah, E.; Slot, H.J.

    2012-01-01

    In the design of subsea flow systems the integrity and reliability is paramount. As the equipment must be designed to operate at a large variety of conditions, inherent to the many processes, evaluation of the integrity is complex. . Flow induced pulsations and vibrations can cause serious design

  8. A novel concept of measuring mass flow rates using flow induced ...

    Indian Academy of Sciences (India)

    ... volumetric flow rate measurement and obviates the need for the knowledge of density is proposed from the measurement of the flow induced stresses in a substrate. The concept is formulated by establishing the relationship between the mass flow rate and the stress in the substrate. To this end, the flow field and the stress ...

  9. Flow induced vibration of subsea gas production system caused by choke valves

    NARCIS (Netherlands)

    Ligterink, N.E.; Groot, R. de; Gharaibah, E.; Slot, H.J.

    2012-01-01

    In the design of subsea flow systems the integrity and reliability is paramount. As the equipment must be designed to operate at a large variety of conditions, inherent to the many processes, evaluation of the integrity is complex. . Flow induced pulsations and vibrations can cause serious design

  10. Textural versus electrostatic exclusion-enrichment effects in the effective chemical transport within the cortical bone: a numerical investigation.

    Science.gov (United States)

    Lemaire, T; Kaiser, J; Naili, S; Sansalone, V

    2013-11-01

    Interstitial fluid within bone tissue is known to govern the remodelling signals' expression. Bone fluid flow is generated by skeleton deformation during the daily activities. Due to the presence of charged surfaces in the bone porous matrix, the electrochemical phenomena occurring in the vicinity of mechanosensitive bone cells, the osteocytes, are key elements in the cellular communication. In this study, a multiscale model of interstitial fluid transport within bone tissues is proposed. Based on an asymptotic homogenization method, our modelling takes into account the physicochemical properties of bone tissue. Thanks to this multiphysical approach, the transport of nutrients and waste between the blood vessels and the bone cells can be quantified to better understand the mechanotransduction of bone remodelling. In particular, it is shown that the electrochemical tortuosity may have stronger implications in the mass transport within the bone than the purely morphological one. Copyright © 2013 John Wiley & Sons, Ltd.

  11. A study on mechanical properties and flow-induced vibrations of coil-shaped holddown spring

    International Nuclear Information System (INIS)

    Kim, Kyu-Tae

    2010-01-01

    The fuel assemblies used in the OPR1000s in Korea employ four coil-shaped hold-down springs to exert compressive load at the top of fuel assembly so that the assemblies may not be damaged by preventing its hydraulic-induced lifting-off from its lower seating surface. However, the coolant flow generates the flow-induced vibration at the coil-shaped hold-down springs which may cause wear on the spring surfaces. A hold-own spring may be fractured if torsional stress acting on its worn area exceeds a stress limit, resulting in the loss of hold-down spring force of the fuel assembly. In this paper, flow-induced vibration tests were performed for standard and improved coil type hold-down springs to investigate the effects of these two hold-down spring designs on flow-induced vibration wear. In parallel, a wide spectrum of mechanical tests was performed to obtain vibration-related characteristics of these two hold-down springs, which can be used as input data for the fuel assembly static and dynamic analysis. It is found that the improved hold-down spring design is better against flow-induced vibration wear than the standard one. With the use of the three-dimensional Solidwork model, the stress-related design lifetime of the improved hold-down spring was estimated by extrapolating its wear data measured from the flow-induced vibration tests, which indicates that the improved HD spring design will maintain integrity during the fuel design lifetime in OPR1000s in Korea.

  12. Energy harvesting by means of flow-induced vibrations on aerospace vehicles

    Science.gov (United States)

    Li, Daochun; Wu, Yining; Da Ronch, Andrea; Xiang, Jinwu

    2016-10-01

    This paper reviews the design, implementation, and demonstration of energy harvesting devices that exploit flow-induced vibrations as the main source of energy. Starting with a presentation of various concepts of energy harvesters that are designed to benefit from a general class of flow-induced vibrations, specific attention is then given at those technologies that may offer, today or in the near future, a potential benefit to extend the operational capabilities and to monitor critical parameters of unmanned aerial vehicles. Various phenomena characterized by flow-induced vibrations are discussed, including limit cycle oscillations of plates and wing sections, vortex-induced and galloping oscillations of bluff bodies, vortex-induced vibrations of downstream structures, and atmospheric turbulence and gusts. It was found that linear or linearized modeling approaches are commonly employed to support the design phase of energy harvesters. As a result, highly nonlinear and coupled phenomena that characterize flow-induced vibrations are neglected in the design process. The Authors encourage a shift in the current design paradigm: considering coupled nonlinear phenomena, and adequate modeling tools to support their analysis, from a design limitation to a design opportunity. Special emphasis is placed on identifying designs and implementations applicable to aircraft configurations. Application fields of flow-induced vibrations-based energy harvesters are discussed including power supply for wireless sensor networks and simultaneous energy harvest and control. A large body of work on energy harvesters is included in this review journal. Whereas most of the references claim direct applications to unmanned aerial vehicles, it is apparent that, in most of the cases presented, the working principles and characteristics of the energy harvesters are incompatible with any aerospace applications. Finally, the challenges that hold back the integration of energy harvesting

  13. Bone tumor

    Science.gov (United States)

    Tumor - bone; Bone cancer; Primary bone tumor; Secondary bone tumor; Bone tumor - benign ... The cause of bone tumors is unknown. They often occur in areas of the bone that grow rapidly. Possible causes include: Genetic defects ...

  14. The origin of flow-induced alignment of spherical colloids in shear-thinning viscoelastic fluids.

    Science.gov (United States)

    Santos de Oliveira, I S; den Otter, W K; Briels, W J

    2012-11-28

    We have studied the poorly understood process of flow-induced structure formation by colloids suspended in shear-thinning fluids. These viscoelastic fluids contain long flexible chains whose entanglements appear and disappear continuously as a result of brownian motion and the applied shear flow. Responsive particle dynamics simulates each chain as a single smooth brownian particle, with slowly evolving inter-particle degrees of freedom accounting for the entanglements. The colloids mixed homogeneously in all simulated quiescent dispersions and they remain dispersed under slow shear flow. Beyond a critical shear rate, which varies depending on the fluid, the colloids aggregate and form flow-aligned strings in the bulk of the fluid. In this work we explore the physical origins of this hitherto unexplained ordering phenomena, both by systematically varying the parameters of the simulated fluids and by analyzing the flow-induced effective colloidal interactions. We also present an expression for the critical shear rate of the studied fluids.

  15. Flow induced vibration of the large-sized sodium valve for MONJU

    International Nuclear Information System (INIS)

    Sato, K.

    1977-01-01

    Measurements have been made on the hydraulic characteristics of the large-sized sodium valves in the hydraulic simulation test loop with water as fluid. The following three prototype sodium valves were tested; (1) 22-inch wedge gate type isolation valve, (2) 22-inch butterfly type isolation valve, and (3) 16-inch butterfly type control valve. In the test, accelerations of flow induced vibrations were measured as a function of flow velocity and disk position. The excitation mechanism of the vibrations is not fully interpreted in these tests due to the complexity of the phenomena, but the experimental results suggest that it closely depends on random pressure fluctuations near the valve disk and flow separation at the contracted cross section between the valve seat and the disk. The intensity of flow induced vibrations suddenly increases at a certain critical condition, which depends on the type of valve and is proportional to fluid velocity. (author)

  16. A Constitutive Model for Flow-Induced Anisotropic Behavior of Viscoelastic Complex Fluids

    International Nuclear Information System (INIS)

    Zhu, H.; De Kee, D.

    2008-01-01

    Flow-induced structural anisotropy could result when a complex fluid system is removed from equilibrium by means of hydrodynamic forces. In this paper, a general theory is developed to model flow induced anisotropic behavior of complex viscoelastic systems, e.g. polymer solutions/melts and suspensions. The rheological properties are characterized by viscosity and relaxation time tensors. We consider a second-rank tensor as a measure of the microstructure. We consider the effect of the flow on the structural changes: i.e. the evolution of the microstructure tensor is governed by a relaxation-type differential equation. We also propose that the viscosity and the relaxation time tensors depend on the second-rank microstructure tensor. That is as the microstructure tensor changes with the applied rate of deformation, the viscosity and relaxation time tensors evolve accordingly. As an example we consider elongational flow of two complex fluids

  17. Disruption of TGF-β signaling in smooth muscle cell prevents flow-induced vascular remodeling

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fu [Department of Vascular Surgery, Peking University People’s Hospital, Beijing (China); Chambon, Pierre [Institut de Génétique et de Biologie Moléculaire et Cellulaire (CNRS UMR7104, INSERM U596, ULP, Collége de France) and Institut Clinique de la Souris, ILLKIRCH, Strasbourg (France); Tellides, George [Department of Surgery, Interdepartmental Program in Vascular Biology and Therapeutics, Yale University School of Medicine, New Haven, CT (United States); Kong, Wei [Department of Physiology and Pathophysiology, Basic Medical College of Peking University, Beijing (China); Zhang, Xiaoming, E-mail: rmygxgwk@163.com [Department of Vascular Surgery, Peking University People’s Hospital, Beijing (China); Li, Wei [Department of Vascular Surgery, Peking University People’s Hospital, Beijing (China)

    2014-11-07

    Highlights: • TGF-β signaling in SMC contributes to the flow-induced vascular remodeling. • Disruption of TGF-β signaling in SMC can prevent this process. • Targeting SM-specific Tgfbr2 could be a novel therapeutic strategy for vascular remodeling. - Abstract: Transforming growth factor-β (TGF-β) signaling has been prominently implicated in the pathogenesis of vascular remodeling, especially the initiation and progression of flow-induced vascular remodeling. Smooth muscle cells (SMCs) are the principal resident cells in arterial wall and are critical for arterial remodeling. However, the role of TGF-β signaling in SMC for flow-induced vascular remodeling remains unknown. Therefore, the goal of our study was to determine the effect of TGF-β pathway in SMC for vascular remodeling, by using a genetical smooth muscle-specific (SM-specific) TGF-β type II receptor (Tgfbr2) deletion mice model. Mice deficient in the expression of Tgfbr2 (MyhCre.Tgfbr2{sup f/f}) and their corresponding wild-type background mice (MyhCre.Tgfbr2{sup WT/WT}) underwent partial ligation of left common carotid artery for 1, 2, or 4 weeks. Then the carotid arteries were harvested and indicated that the disruption of Tgfbr2 in SMC provided prominent inhibition of vascular remodeling. And the thickening of carotid media, proliferation of SMC, infiltration of macrophage, and expression of matrix metalloproteinase (MMP) were all significantly attenuated in Tgfbr2 disruption mice. Our study demonstrated, for the first time, that the TGF-β signaling in SMC plays an essential role in flow-induced vascular remodeling and disruption can prevent this process.

  18. Lattice Boltzmann simulation of fluid flow induced by thermal effect in heterogeneity porous media

    Directory of Open Access Journals (Sweden)

    Hou Peng

    2017-01-01

    Full Text Available In this paper, a coupled lattice Boltzmann model is used to visually study fluid flow induced by thermal effect in heterogeneity porous media reconstructed by the quartet structure generation set. The fluid flow behavior inside porous media is presented and analyzed under different conditions. The simulation results indicate that the pore morphological properties of porous media and the Rayleigh number have noticeable impact on the velocity distribution and flow rate of fluid.

  19. Mechanical loading disrupts osteocyte plasma membranes which initiates mechanosensation events in bone.

    Science.gov (United States)

    Yu, Kanglun; Sellman, David P; Bahraini, Anoosh; Hagan, Mackenzie L; Elsherbini, Ahmed; Vanpelt, Kayce T; Marshall, Peyton L; Hamrick, Mark W; McNeil, Anna; McNeil, Paul L; McGee-Lawrence, Meghan E

    2018-02-01

    Osteocytes sense loading in bone, but their mechanosensation mechanisms remain poorly understood. Plasma membrane disruptions (PMD) develop with loading under physiological conditions in many cell types (e.g., myocytes, endothelial cells). These PMD foster molecular flux across cell membranes that promotes tissue adaptation, but this mechanosensation mechanism had not been explored in osteocytes. Our goal was to investigate whether PMD occur and initiate consequent mechanotransduction in osteocytes during physiological loading. We found that osteocytes experience PMD during in vitro (fluid flow) and in vivo (treadmill exercise) mechanical loading, in proportion to the level of stress experienced. In fluid flow studies, osteocyte PMD preferentially formed with rapid as compared to gradual application of loading. In treadmill studies, osteocyte PMD increased with loading in weight bearing locations (tibia), but this trend was not seen in non-weight bearing locations (skull). PMD initiated osteocyte mechanotransduction including calcium signaling and expression of c-fos, and repair rates of these PMD could be enhanced or inhibited pharmacologically to alter downstream mechanotransduction and osteocyte survival. PMD may represent a novel mechanosensation pathway in bone and a target for modifying skeletal adaptation signaling in osteocytes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:653-662, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  20. Regulation of endothelial barrier function during flow-induced conversion to an arterial phenotype.

    Science.gov (United States)

    Seebach, Jochen; Donnert, Gerald; Kronstein, Romy; Werth, Sebastian; Wojciak-Stothard, Beata; Falzarano, Darryl; Mrowietz, Christof; Hell, Stefan W; Schnittler, Hans-J

    2007-08-01

    Flow-induced conversion of endothelial cells into an elongated arterial phenotype requires a coordinated regulation of cell junctions. Here we investigated the effect of acute and chronic flow on junction regulation. Using an extended experimental setup that allows analyses of endothelial barrier function under flow conditions, we found a flow-induced upregulation of the transendothelial electrical resistance within minutes. This was accompanied by an increase in actin filaments along the junctions and vascular endothelial (VE)-cadherin clustering, which was identified at nanoscale resolution by stimulated emission depletion microscopy. In addition, a transient tyrosine phosphorylation of VE-cadherin and catenins occurred within minutes following the onset of flow. VE-cadherin and actin distribution were maintained under chronic flow over 24 h and associated with the upregulation of VE-cadherin and alpha-catenin expression, thus compensating for the cell elongation-mediated increase in cell border length. Importantly, all observed effects were rac1 dependent as verified by the inhibitory effect of dominant negative N17rac1. These results show that flow-induced conversion of endothelial cells into an arterial phenotype occurs while intercellular junctions remain intact. The data place rac1 in a central multimodal regulatory position that might be important in the development of vascular diseases, such as arteriosclerosis.

  1. Flow-induced and acoustically induced vibration experience in operating gas-cooled reactors

    International Nuclear Information System (INIS)

    Halvers, L.J.

    1977-03-01

    An overview has been presented of flow-induced and acoustically induced vibration failures that occurred in the past in gas-cooled graphite-moderated reactors, and the importance of this experience for the Gas-Cooled Fast-Breeder Reactor (GCFR) project has been assessed. Until now only failures in CO 2 -cooled reactors have been found. No problems with helium-cooled reactors have been encountered so far. It is shown that most of the failures occurred because flow-induced and acoustically induced dynamic loads were underestimated, while at the same time not enough was known about the influence of environmental parameters on material behavior. All problems encountered were solved. The comparison of the influence of the gas properties on acoustically induced and flow-induced vibration phenomena shows that the interaction between reactor design and the thermodynamic properties of the primary coolant precludes a general preference for either carbon dioxide or helium. The acoustic characteristics of CO 2 and He systems are different, but the difference in dynamic loadings due to the use of one rather than the other remains difficult to predict. A slight preference for helium seems, however, to be justified

  2. A new methodology for predicting flow induced vibration in industrial components

    International Nuclear Information System (INIS)

    Gay, N.

    1997-12-01

    Flow induced vibration damage is a major concern for designers and operators of industrial components. For example, nuclear power plant operators have currently to deal with such flow induced vibration problems, in steam generator tube bundles, control rods or nuclear fuel assemblies. Some methodologies have thus been recently proposed to obtain an accurate description of the flow induced vibration phenomena. These methodologies are based on unsteady semi-analytical models for fluid-dynamic forces, associated with non-dimensional fluid force coefficients generally obtained from experiments. The aim is to determine the forces induced by the flow on the structure, and then to take account of these forces to derive the dynamic behaviour of the component under flow excitation. The approach is based on a general model for fluid-dynamic forces, using several non-dimensional parameters that cannot be reached through computation. These parameters are then determined experimentally on simplified test sections, representative of the component, of the flow and of the fluid-elastic coupling phenomena. Predicting computations of the industrial component can then be performed for various operating configurations, by applying laws of similarity. The major physical mechanisms involved in complex fluid-structure interaction phenomena have been understood and modelled. (author)

  3. Endothelial mechanotransduction proteins and vascular function are altered by dietary sucrose supplementation in healthy young male subjects

    DEFF Research Database (Denmark)

    Gliemann, Lasse; Rytter, Nicolai; Lindskrog, Mads

    2017-01-01

    Endothelial mechanotransduction is important for vascular function but alterations and activation of vascular mechanosensory proteins have not been investigated in humans. In endothelial cell culture, simple sugars effectively impair mechanosensor proteins. To study mechanosensor- and vascular...... by ultrasound doppler. A muscle biopsy was obtained from the thigh muscle before and after acute passive leg movement, to asses the protein amount and phosphorylation status of mechanosensory proteins and NADPH oxidase. The sucrose intervention led to a reduced flow response to passive movement (by 17 ± 2...... %) and to 12 watts of active exercise (by 9 ± 1 %), indicating impaired vascular function. Reduced flow response to passive and active exercise was paralleled by a significant upregulation of Platelet endothelial cell adhesion molecule (PECAM-1), endothelial nitric oxide synthase, NADPH oxidase and the Rho...

  4. Flow-induced decentering and tube support interaction for steam generator tubes: experiment and physical interpretation

    International Nuclear Information System (INIS)

    Gay, N.; Granger, S.

    1992-11-01

    Maintaining PWR components under reliable operating conditions requires a complex design to prevent various damaging processes including flow-induced vibration and wear mechanisms. To improve the prediction of tube/support interaction and wear in PWR components, EDF has undertaken a comprehensive program oriented to both experimental and computational studies. The present paper illustrates one aspect of this program, related to the determination of contact forces between steam generator tubes and anti-vibration bars (AVBs). The dynamic, nonlinear behavior of a U-tube excited by an air cross-flow is investigated on the CLAVECIN experiment. Interesting and rather unexpected results have been obtained, by varying clearances and flow velocities. The paper is focused on four main points: (i) the originality of the experiment with a force measurement device located in flow; (ii) the importance of a refined data processing for accurately measuring contact forces; (iii) the presentation of the unexpected phenomena revealed in the CLAVECIN experiment, i.e. a flow-induced decentering of the tube which changed the initial tube/AVB clearance, and the consequences on tube/support interaction; (iv) the influence of the actual tube/support clearance in flow on wear mechanisms. The work, presented in the second part of this paper, concentrates exclusively on the physical interpretation of the flow-induced decentering phenomenon and on the theoretical analysis of its consequences on dynamic tube/support interaction. We show that the flow-induced decentering phenomenon can be generated by an unstable quasi-static coupling between the flexible tube and the confined flow, in the vicinity of the support system. This phenomenon is not specific to the CLAVECIN tests and it can be expected every time that a movable obstacle is subjected to confined flow. Moreover, in single-sided impacting conditions, the theoretical analysis confirms the linear relation, found in the CLAVECIN tests

  5. An advanced tube wear and fatigue workstation to predict flow induced vibrations of steam generator tubes

    International Nuclear Information System (INIS)

    Gay, N.; Baratte, C.; Flesch, B.

    1997-01-01

    Flow induced tube vibration damage is a major concern for designers and operators of nuclear power plant steam generators (SG). The operating flow-induced vibrational behaviour has to be estimated accurately to allow a precise evaluation of the new safety margins in order to optimize the maintenance policy. For this purpose, an industrial 'Tube Wear and Fatigue Workstation', called 'GEVIBUS Workstation' and based on an advanced methodology for predictive analysis of flow-induced vibration of tube bundles subject to cross-flow has been developed at Electricite de France. The GEVIBUS Workstation is an interactive processor linking modules as: thermalhydraulic computation, parametric finite element builder, interface between finite element model, thermalhydraulic code and vibratory response computations, refining modelling of fluid-elastic and random forces, linear and non-linear dynamic response and the coupled fluid-structure system, evaluation of tube damage due to fatigue and wear, graphical outputs. Two practical applications are also presented in the paper; the first simulation refers to an experimental set-up consisting of a straight tube bundle subject to water cross-flow, while the second one deals with an industrial configuration which has been observed in some operating steam generators i.e., top tube support plate degradation. In the first case the GEVIBUS predictions in terms of tube displacement time histories and phase planes have been found in very good agreement with experiment. In the second application the GEVIBUS computation showed that a tube with localized degradation is much more stable than a tube located in an extended degradation zone. Important conclusions are also drawn concerning maintenance. (author)

  6. Pulsatile flow-induced angiogenesis: role of G(i) subunits.

    Science.gov (United States)

    Cullen, John P; Sayeed, Shariq; Sawai, Rebecca S; Theodorakis, Nicholas G; Cahill, Paul A; Sitzmann, James V; Redmond, Eileen M

    2002-10-01

    Angiogenesis plays a key role in the growth and function of normal and pathological tissues. We investigated the effect of pulsatile flow on endothelial cell (EC) in vitro angiogenic activity. Bovine aortic ECs were exposed to "static" or "flow" (1.2 to 67.0 mL/min, shear stress 1.4 to 19.2 dyne/cm2) conditions for 2 to 24 hours. After exposure, angiogenesis was measured as tubule formation on Matrigel, and EC migration was assessed by filter migration assay. Pulsatile flow increased angiogenesis and EC migration in a temporal and force-dependent manner, with a maximal effect at 16 hours (13.2 dyne/cm2). Pertussis toxin completely inhibited the effect of pulsatile flow on angiogenesis and migration. Transfection of ECs with inhibitory mutants of the alpha subunit of G(i)1 or G(i)3, but not G(i)2, inhibited the flow-induced angiogenic response by 61+/-2% and 32+/-6%, respectively, whereas transfection with constitutively activated mutants of the alpha subunit of G(i)1 or G(i)3, but not G(i)2, increased the flow-induced response by 202+/-23% and 70+/-4%, respectively. In contrast, inhibition of Gbetagamma by the carboxy terminal fragment of beta-adrenergic receptor kinase overexpression increased the flow-induced response by 82+/-8%. These results suggest that pulsatile flow stimulates angiogenesis and that this effect is mediated by activation of G(ialpha)1 or G(ialpha)3, but not Gbetagamma, subunits.

  7. Flow-induced vibration for light-water reactors. Progress report, April 1978-December 1979

    International Nuclear Information System (INIS)

    Schardt, J.F.

    1980-03-01

    Flow-Induced vibration for Light Water Reactors (FIV for LWRs) is a four-year program designed to improve the FIV performance of light water reactors through the development of design criteria, analytical models for predicting behavior of components, general scaling laws to improve the accuracy of reduced-scale tests, and the identification of high FIV risk areas. The program commenced December 1, 1976, but was suspended on September 30, 1978, due to a shift in Department of Energy (DOE) priorities away from LWR productivity/availability. It was reinitiated as of August 1, 1979. This progress report summarizes the accomplishments achieved during the period from April 1978 to December 1979

  8. Bone Diseases

    Science.gov (United States)

    ... avoid smoking and drinking too much alcohol. Bone diseases can make bones easy to break. Different kinds ... break Osteogenesis imperfecta makes your bones brittle Paget's disease of bone makes them weak Bones can also ...

  9. Exogenous NO suppresses flow-induced endothelium-derived NO production because of depletion of tetrahydrobiopterin.

    Science.gov (United States)

    Mochizuki, Seiichi; Sipkema, Pieter; Goto, Masami; Hiramatsu, Osamu; Nakamoto, Hiroshi; Toyota, Eiji; Kajita, Tatsuya; Shigeto, Fumiyuki; Yada, Toyotaka; Ogasawara, Yasuo; Kajiya, Fumihiko

    2005-02-01

    Exogenous nitric oxide (NO) suppresses endothelium-derived NO production. We were interested in determining whether this is also the case in flow-induced endothelium-derived NO production. If so, then is the mechanism because of intracellular depletion of tetrahydrobiopterin [BH4; a cofactor of NO synthase (NOS)], which results in superoxide production by uncoupled NOS? Isolated canine femoral arteries were perfused with 100 microM S-nitroso-N-acetylpenicillamine (SNAP; an NO donor) and/or 64 microM BH4. Perfusion of SNAP suppressed flow-induced NO production, which was evaluated as a change in the slope of the linear relationship between perfusion rate and NO production rate (P production (n = 7). Concomitant perfusion of SNAP and 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron; 1 mM; a membrane-permeable superoxide scavenger) also retained the control-level NO production (n = 7), whereas perfusion of Tiron after SNAP could not return the NO production to the control level (P production by superoxide released from uncoupled NOS because of intracellular BH4 depletion.

  10. Flow induced vibration mock-up test for heat exchanger tubes of PWR steam generator

    International Nuclear Information System (INIS)

    Iwase, T.; Takai, M.; Uwagawa, S.; Nakamura, T.; Hirota, K.; Suzuta, T.

    2000-01-01

    It is one of the most important subjects to estimate the flow-related stability of the heat exchanger tubes. A large scale model steam generator has been developed to verify the stability of the tubes in the Japanese PWR steam generators for the two-phase flow-induced vibration and to accumulate related technical data of thermal-hydraulic and flow-induced vibration of U-bend tube bundle. The model steam generator has 230 U-bend tubes of 46 different radius and 5 columns for each of practical diameter and material, and the anti vibration bars are inserted into each spacing between tube arrays. The freon R123 has been used as the secondary side fluid in stead of water-steam two-phase. In the test, void fraction and interfacial velocities in U-bend and straight tube-bundle are measured with bi-optical probes, and vibration responses of some selected tubes are measured with strain gauges and accelerators. It is verified that the U-bend tubes are stable when they are supported as the design requires under normal and some over power no operating condition. The thermal hydraulic code FIT-III has been well verified with measured thermal and hydraulic data. (author)

  11. A nonlinear flow-induced energy harvester by considering effects of fictitious springs

    Science.gov (United States)

    Zhang, Guangcheng; Lin, Yueh-Jaw

    2018-01-01

    In this paper, a newly proposed energy harvesting approach involving nonlinear coupling effects is demonstrated by utilizing a pair of inducing bluff bodies that are put on both sides of the flag-shaped cantilever beam, and placed in a side-by-side configuration to harvest the energy of the flow. One patch of macro fiber composite is attached to the fixed end of the cantilever beam to facilitate converting the kinetic energy into electric power. It is the first time in recent literature that two fluid dynamic phenomena (i.e. the vortex shedding and the Bernoulli effect) are considered simultaneously in the flow-induced energy harvesting field. The fictitious springs are introduced to explain the nonlinear characteristics of the proposed structure. With the effect of the fictitious springs, the speed range of the flow-induced energy harvester is extended. The proposed structure not only improves the output of the induced-based energy harvester compared to one that has just one cylinder, but can also be utilized in an actual hostile ambient environment. The experimental results for the energy harvester prototype are also investigated. The output power of the energy harvester with two cylinders (D = 25 mm) is measured to be 1.12 μW when the flow speed is 0.325 m s‑1 and the center-to-center transverse spacing is 45 mm. This research also delves into the geometric variations of the proposed structure and its optimization.

  12. Computing flow-induced stresses of injection molding based on PTT model

    International Nuclear Information System (INIS)

    Cao Wei; Gan Shufeng; Li Qian; Shen Changyu

    2010-01-01

    A numerical approach is introduced to solve the viscoelastic flow problem of filling and post-filling in injection molding. The governing equations are in terms of compressible, non-isothermal fluid, and the constitutive equation is based on the PTT model. By introducing some hypotheses according to the characteristics of injection molding, a quasi-Poisson type equation about pressure is derived with part integration. Besides, an analytical form of flow-induced stress is also generalized by using Undermined Coefficient Method. The conventional Galerkin approach is employed to solve the derived pressure equation, and the 'upwind' difference scheme is used to discrete the energy equation. Coupling is achieved between velocity and stress by Super Relax Iteration Method. The flow in the test mold is investigated by comparing the numerical results and photoelastic photos for polystyrene, showing flow-induced stresses are closely related to melt temperatures. The filling of a two-cavity box is also studied to investigate the viscoelastic effects on real injection molding.

  13. Study on numerical methods for transient flow induced by speed-changing impeller of fluid machinery

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dazhuan; Chen, Tao; Wang, Leqin [Zhejiang University, Hangzhou (China); Cheng, Wentao [Research Institute of Product Quality and Standard of Ministry of Water Recourse, Hangzhou (China); Sun, Youbo [Zhejiang Academy of Safety Science and Technology, Hangzhou (China)

    2013-06-15

    In order to establish a reliable numerical method for solving the transient rotating flow induced by a speed-changing impeller, two numerical methods based on finite volume method (FVM) were presented and analyzed in this study. Two-dimensional numerical simulations of incompressible transient unsteady flow induced by an impeller during starting process were carried out respectively by using DM and DSR methods. The accuracy and adaptability of the two methods were evaluated by comprehensively comparing the calculation results. Moreover, an intensive study on the application of DSR method was conducted subsequently. The results showed that transient flow structure evolution and transient characteristics of the starting impeller are obviously affected by the starting process. The transient flow can be captured by both two methods, and the DSR method shows a higher computational efficiency. As an application example, the starting process of a mixed-flow pump was simulated by using DSR method. The calculation results were analyzed by comparing with the experiment data.

  14. Study on numerical methods for transient flow induced by speed-changing impeller of fluid machinery

    International Nuclear Information System (INIS)

    Wu, Dazhuan; Chen, Tao; Wang, Leqin; Cheng, Wentao; Sun, Youbo

    2013-01-01

    In order to establish a reliable numerical method for solving the transient rotating flow induced by a speed-changing impeller, two numerical methods based on finite volume method (FVM) were presented and analyzed in this study. Two-dimensional numerical simulations of incompressible transient unsteady flow induced by an impeller during starting process were carried out respectively by using DM and DSR methods. The accuracy and adaptability of the two methods were evaluated by comprehensively comparing the calculation results. Moreover, an intensive study on the application of DSR method was conducted subsequently. The results showed that transient flow structure evolution and transient characteristics of the starting impeller are obviously affected by the starting process. The transient flow can be captured by both two methods, and the DSR method shows a higher computational efficiency. As an application example, the starting process of a mixed-flow pump was simulated by using DSR method. The calculation results were analyzed by comparing with the experiment data.

  15. Role of skin friction drag during flow-induced reconfiguration of a flexible thin plate

    Science.gov (United States)

    Bhati, Awan; Sawanni, Rajat; Kulkarni, Kaushik; Bhardwaj, Rajneesh

    2018-02-01

    We investigate drag reduction due to the flow-induced reconfiguration of a flexible thin plate in presence of skin friction drag at low Reynolds Number. The plate is subjected to a uniform free stream and is tethered at one end. We extend existing models in the literature to account for the skin friction drag. The total drag on the plate with respect to a rigid upright plate decreases due to flow-induced reconfiguration and further reconfiguration increases the total drag due to increase in skin friction drag. A critical value of Cauchy number ($Ca$) exists at which the total drag on the plate with respect to a rigid upright plate is minimum at a given Reynolds number. The reconfigured shape of the plate for this condition is unique, beyond which the total drag increases on the plate even with reconfiguration. The ratio of the form drag coefficient for an upright rigid plate and skin drag coefficient for a horizontal rigid plate ($\\lambda$) determines the critical Cauchy number ($Ca_{cr}$). We propose modification in the drag scaling with free stream velocity ($F_{x}$ ${\\propto}$ $U^{n}$) in presence of the skin friction drag. The following expressions of $n$ are found for $0.01 \\leq Re \\leq 1$, $n = 4/5 + {\\lambda}/5$ for 1 $\\leq$ $Ca$ $drag and buoyancy on the drag reduction. An assessment of the feasibility of experiments is presented in order to translate the present model to physical systems.

  16. Changes in muscle cell metabolism and mechanotransduction are associated with myopathic phenotype in a mouse model of collagen VI deficiency.

    Directory of Open Access Journals (Sweden)

    Sara De Palma

    Full Text Available This study identifies metabolic and protein phenotypic alterations in gastrocnemius, tibialis anterior and diaphragm muscles of Col6a1(-/- mice, a model of human collagen VI myopathies. All three muscles of Col6a1(-/- mice show some common changes in proteins involved in metabolism, resulting in decreased glycolysis and in changes of the TCA cycle fluxes. These changes lead to a different fate of α-ketoglutarate, with production of anabolic substrates in gastrocnemius and tibialis anterior, and with lipotoxicity in diaphragm. The metabolic changes are associated with changes of proteins involved in mechanotransduction at the myotendineous junction/costameric/sarcomeric level (TN-C, FAK, ROCK1, troponin I fast and in energy metabolism (aldolase, enolase 3, triose phosphate isomerase, creatine kinase, adenylate kinase 1, parvalbumin, IDH1 and FASN. Together, these change may explain Ca(2+ deregulation, impaired force development, increased muscle-relaxation-time and fiber damage found in the mouse model as well as in patients. The severity of these changes differs in the three muscles (gastrocnemius

  17. Substrate and mechanotransduction influence SERCA2a localization in human pluripotent stem cell-derived cardiomyocytes affecting functional performance

    Directory of Open Access Journals (Sweden)

    Sebastian Martewicz

    2017-12-01

    In this work, we show involvement of the mechanotransduction pathway RhoA/ROCK in the structural reorganization of hPSC-derived cardiomyocytes after adhesion plating. These structural changes have a major impact on the intracellular localization of SERCA2 pumps and concurrent improvement in calcium cycling. The process is triggered by cell interaction with the culture substrate, which mechanical cues drive sarcomeric alignment and SERCA2a spreading and relocalization from a perinuclear to a whole-cell distribution. This structural reorganization is mediated by the mechanical properties of the substrate, as shown by the process failure in hPSC-CMs cultured on soft 4 kPa hydrogels as opposed to physiologically stiff 16 kPa hydrogels and glass. Finally, pharmacological inhibition of Rho-associated protein kinase (ROCK by different compounds identifies this specific signaling pathway as a major player in SERCA2 localization and the associated improvement in hPSC-CMs calcium handling ability in vitro.

  18. Changes in Muscle Cell Metabolism and Mechanotransduction Are Associated with Myopathic Phenotype in a Mouse Model of Collagen VI Deficiency

    Science.gov (United States)

    De Palma, Sara; Leone, Roberta; Grumati, Paolo; Vasso, Michele; Polishchuk, Roman; Capitanio, Daniele; Braghetta, Paola; Bernardi, Paolo; Bonaldo, Paolo; Gelfi, Cecilia

    2013-01-01

    This study identifies metabolic and protein phenotypic alterations in gastrocnemius, tibialis anterior and diaphragm muscles of Col6a1−/− mice, a model of human collagen VI myopathies. All three muscles of Col6a1−/− mice show some common changes in proteins involved in metabolism, resulting in decreased glycolysis and in changes of the TCA cycle fluxes. These changes lead to a different fate of α-ketoglutarate, with production of anabolic substrates in gastrocnemius and tibialis anterior, and with lipotoxicity in diaphragm. The metabolic changes are associated with changes of proteins involved in mechanotransduction at the myotendineous junction/costameric/sarcomeric level (TN-C, FAK, ROCK1, troponin I fast) and in energy metabolism (aldolase, enolase 3, triose phosphate isomerase, creatine kinase, adenylate kinase 1, parvalbumin, IDH1 and FASN). Together, these change may explain Ca2+ deregulation, impaired force development, increased muscle-relaxation-time and fiber damage found in the mouse model as well as in patients. The severity of these changes differs in the three muscles (gastrocnemiusmass-to-tendon (myotendineous junction) ratio and to muscle morphology. PMID:23437220

  19. CFD simulation of flow-induced vibration of an elastically supported airfoil

    Directory of Open Access Journals (Sweden)

    Šidlof Petr

    2016-01-01

    Full Text Available Flow-induced vibration of lifting or control surfaces in aircraft may lead to catastrophic consequences. Under certain circumstances, the interaction between the airflow and the elastic structure may lead to instability with energy transferred from the airflow to the structure and with exponentially increasing amplitudes of the structure. In the current work, a CFD simulation of an elastically supported NACA0015 airfoil with two degrees of freedom (pitch and plunge coupled with 2D incompressible airflow is presented. The geometry of the airfoil, mass, moment of inertia, location of the centroid, linear and torsional stiffness was matched to properties of a physical airfoil model used for wind-tunnel measurements. The simulations were run within the OpenFOAM computational package. The results of the CFD simulations were compared with the experimental data.

  20. Research and design of underwater flow-induced vibration energy harvester based on Karman vortex street

    Science.gov (United States)

    Yao, Gang; Wang, Hai; Yang, Chunlai; Wen, Li

    2017-03-01

    With the increasing development of wireless sensor network (WSN), power supply for WSN nodes had attracted increasing attention, and the energy harvesting system based on Karman vortex street has been widely used in underwater WSN. But the research of the influences of affecting factors towards the energy harvesting system is yet to be completed. So, in this paper, an underwater flow-induced vibration energy harvesting system based on Karman vortex street was proposed and tested. The influence of bluff body geometry and flow velocity towards the performance of the energy harvesting has been researched. The results showed that the output voltage increased as the diameter of bluff body and the water velocity increase. The power generation efficiency was the best when the shape of bluff body was circular.

  1. Modeling and control of flow-induced vibrations of a flexible hydrofoil in viscous flow

    Science.gov (United States)

    Caverly, Ryan James; Li, Chenyang; Chae, Eun Jung; Forbes, James Richard; Young, Yin Lu

    2016-06-01

    In this paper, a reduced-order model (ROM) of the flow-induced vibrations of a flexible cantilevered hydrofoil is developed and used to design an active feedback controller. The ROM is developed using data from high-fidelity viscous fluid-structure interaction (FSI) simulations and includes nonlinear terms to accurately capture the effect of lock-in. An active linear quadratic Gaussian (LQG) controller is designed based on a linearization of the ROM and is implemented in simulation with the ROM and the high-fidelity viscous FSI model. A controller saturation method is also presented that ensures that the control force applied to the system remains within a prescribed range. Simulation results demonstrate that the LQG controller successfully suppresses vibrations in both the ROM and viscous FSI simulations using a reasonable amount of control force.

  2. Study and analysis on the flow induced vibration of the core barrel of PWR

    International Nuclear Information System (INIS)

    Yao Weida; Shi Guolin; Jiang Nanyan; Peng YongYong; Zhang Huijun; Wang Yufen; Xie Yongcheng; Guo Chunhua; Shen Qinping

    1989-01-01

    The deduction of the resemblance criterion and the design of the test model by applying flow-solid coupling theory are described. The model analysis of a core barrel both in the air and stationary water were performed in a 1:10 model, thus obtaining the dynamic characteristic. In a 1:5 reactor model with a hydraulic closed loop, the inner structure and support were modeled for performing hydraulic closed loop, the inner structure and support were modeled for performing hydraulic vibration test of the core barrel. The flow induced pulse pressure of the core barrel and corresponding response were obtained by using miniature pressure capsule, strain gauge and accelerometer. Power spectrum, correlation functions, transfer function and amplitudes under different flow velocities were calculated. The hydraulic vibration test shows that the core barrel will be in safety during its 30-year life time

  3. Leakage-flow induced vibrations of a chimney structure suspended in a liquid flow

    International Nuclear Information System (INIS)

    Chung, H.

    1983-01-01

    This paper presents the results of flow-induced vibration tests conducted to assess the vibration characteristics of a chimney structure suspended in a liquid flow. The test article is a full-scale model of a flow chimney used in a nuclear reactor as a part of reactor upper internals. Tests were performed by simulating all pertinent prototype conditions achievable in a laboratory environment. The test results show that there exists a fluid-elastic instability of the chimney motion which has a distinct lock-in phenomenon with respect to the flow rate. This unstable vibration is associated with the leakage-flow-modulated excitation through the small clearances between the chimney and its supports

  4. Flow-induced symmetry reduction in two-dimensional reaction-diffusion system

    Science.gov (United States)

    Hu, Hai Xiang; Li, Xiao Chun; Li, Qian Shu

    2009-03-01

    The influence of uniform flow on the pattern formation is investigated in a two-dimensional reaction-diffusion system. It is found that the convective flow plays a key role on pattern modulation. Both traveling and stationary periodic patterns are obtained. At moderate flow rates, the perfect hexagon, phase-shifted hexagon and stable square, which are essentially unstable in unperturbed reaction-diffusion systems, are obtained. These patterns move downstream. If the flow rate is increased further, the stationary flow-oriented stripes develop and compete with the spots. If the flow rate exceeds some critical value, the system is convectively unstable and the stationary stripes prevail against the traveling spots. The above patterns all have the same critical wavenumber associated with Turing bifurcation, which indicates that Turing instability produces the patterns while the flow induces the symmetry reduction, i.e., from six-fold symmetry to four-fold one, and to two-fold one ultimately.

  5. Modeling of movement-induced and flow-induced fluid forces in fast switching valves

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Johansen, Per; Schmidt, Lasse

    2015-01-01

    Fast switching fluid power valves set strict requirements on performance, size and energy efficiency and simulation models are therefore needed to obtain good designs of such components. The valve moving member is subject to fluid forces depending on the valve flow rate and movement of the valve...... member itself. These fluid forces may be accurately simulated using Computational Fluid Dynamics (CFD) analysis, but such models suffer from being computationally expensive and is not suited for optimization routines. In this paper, a computationally inexpensive method for modeling the fluid forces...... is proposed, which includes both the flow-induced fluid forces and the movement-induced fluid forces resulting from movement of the valve moving member. The movement-induced fluid force model is based on a known solution to the linearized Navier-Stokes equations. A method for accurately simulating the flow...

  6. Non-Newtonian Flow-Induced Deformation From Pressurized Cavities in Absorbing Porous Tissues

    Science.gov (United States)

    Ahmed, Aftab; Siddique, Javed

    2017-11-01

    We investigate the behavior of a spherical cavity in a soft biological tissue modeled as a deformable porous material during an injection of non-Newtonian fluid that follows a power law model. Fluid flows into the neighboring tissue due to high cavity pressure where it is absorbed by capillaries and lymphatics at a rate proportional to the local pressure. Power law fluid pressure and displacement of solid in the tissue are computed as function of radial distance and time. Numerical solutions indicate that shear thickening fluids exhibit less fluid pressure and induce small solid deformation as compared to shear thinning fluids. The absorption in the biological tissue increases as a consequence of flow induced deformation for power law fluids. In most cases non-Newtonian results are compared with viscous fluid case to magnify the differences.

  7. First international symposium on Flow Induced Noise and Vibration Issues and Aspects

    CERN Document Server

    Rosa, Sergio; Franco, Francesco; Guyader, Jean-Louis; Hambric, Stephen; Flinovia - Flow Induced Noise and Vibration Issues and Aspects

    2015-01-01

    Flow induced vibration and noise (FIVN) remains a critical research topic. Even after over 50 years of intensive research, accurate and cost-effective FIVN simulation and measurement techniques remain elusive. This book gathers the latest research from some of the most prominent experts in the field. It describes methods for characterizing wall pressure fluctuations, including subsonic and supersonic turbulent boundary layer flows over smooth and rough surfaces using computational methods like Large Eddy Simulation;
for inferring wall pressure fluctuations using inverse techniques based on panel vibrations or holographic pressure sensor arrays;
for calculating the resulting structural vibrations and radiated sound using traditional finite element methods, as well as advanced methods like Energy Finite Elements;
for using scaling approaches to universally collapse flow-excited vibration and noise spectra; and for computing time histories of structural response, including alternating stresses. This book p...

  8. Double cascade turbulence and Richardson dispersion in a horizontal fluid flow induced by Faraday waves.

    Science.gov (United States)

    von Kameke, A; Huhn, F; Fernández-García, G; Muñuzuri, A P; Pérez-Muñuzuri, V

    2011-08-12

    We report the experimental observation of Richardson dispersion and a double cascade in a thin horizontal fluid flow induced by Faraday waves. The energy spectra and the mean spectral energy flux obtained from particle image velocimetry data suggest an inverse energy cascade with Kolmogorov type scaling E(k) ∝ k(γ), γ ≈ -5/3 and an E(k) ∝ k(γ), γ ≈ -3 enstrophy cascade. Particle transport is studied analyzing absolute and relative dispersion as well as the finite size Lyapunov exponent (FSLE) via the direct tracking of real particles and numerical advection of virtual particles. Richardson dispersion with ∝ t(3) is observed and is also reflected in the slopes of the FSLE (Λ ∝ ΔR(-2/3)) for virtual and real particles.

  9. Flow induced on a salt waterbody due to the impingement of a freshwater drop

    Science.gov (United States)

    Benouaguef, Islam; Amah, Edison; Musunuri, Naga; Blackmore, Denis; Fischer, Ian; Singh, Pushpendra

    2017-11-01

    The particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) techniques are used to study the flow induced on the surface of a salt waterbody when a drop impinges on the surface. The measurements show that the impingement of a fresh water drop causes a strong axisymmetric solutocapillary flow about the vertical line passing through the center of impact. The fluid directly below the center of impact rises upward, and near the surface it moves away from the center of impact. The flow, which develops within a fraction of second after the impact, persists for several seconds and the volume of water circulated is two orders of magnitude larger than the volume circulated when a freshwater drop falls on a freshwater body.

  10. PIV measurements of acoustic and flow-induced vibration in main stream lines

    International Nuclear Information System (INIS)

    Li, Yanrong; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    Systems with closed side-branches are liable to an excitation of sound, as called cavity tone. In this study, flow-induced acoustic resonances of piping systems containing closed side-branches were investigated experimentally. The present investigation on the coaxial closed side-branches is the first rudimentary study to measure the pressure at the downstream side opening of the cavity by microphone and to visualize the fluid flow in the cross-section by using PIV. High-time-resolved PIV has a possibility to analyze the velocity field and the relation between sound propagation and flow field. The fluid flows at different points in the cavity interact with some phase differences and the relation can be clarified. (author)

  11. Axial-flow-induced vibration for a rod supported by translational springs at both ends

    International Nuclear Information System (INIS)

    Kang, H.S.; Song, K.N.; Kim, H.K.; Yoon, K.H.

    2003-01-01

    An axial-flow-induced vibration model was proposed for a rod supported by two translational springs at both ends in order to evaluate the sensitivity to spring stiffness on the FIV for a PWR fuel rod. For developing the model, a one-mode approximation was made based on the assumption that the first mode was dominant in vibration behavior of the single span rod. The first natural frequency and mode shape functions for the flow-induced vibration, called the FIV, model were derived by using Lagrange's method. The vibration displacements were calculated by both of the spring-supported rod and the simple-supported (SS) one. As a result, the vibration displacement for the spring-supported (50 kN m -1 ) rod was 15-20% larger than that of the SS rod when the rods are in axial flow of 5-8 m s -1 velocity. The discrepancy between both displacements became much larger as flow velocity increased, and that of the rod having the short span length was larger than that of the rod having the long span length although the displacement value itself of the long span rod was larger than that of the short one. The vibration displacement for the spring-supported rod appeared to decrease with the increase of the spring constant. Since single span beam supported by the two translational springs are focused on in this paper, further study will be needed to reflect more realistic supporting conditions of the PWR fuel rod such as two springs and four dimples and cross or swirling flow caused by the mixing vane of the spacer grid

  12. Effect of angle on flow-induced vibrations of pinniped vibrissae.

    Directory of Open Access Journals (Sweden)

    Christin T Murphy

    Full Text Available Two types of vibrissal surface structures, undulated and smooth, exist among pinnipeds. Most Phocidae have vibrissae with undulated surfaces, while Otariidae, Odobenidae, and a few phocid species possess vibrissae with smooth surfaces. Variations in cross-sectional profile and orientation of the vibrissae also exist between pinniped species. These factors may influence the way that the vibrissae behave when exposed to water flow. This study investigated the effect that vibrissal surface structure and orientation have on flow-induced vibrations of pinniped vibrissae. Laser vibrometry was used to record vibrations along the whisker shaft from the undulated vibrissae of harbor seals (Phoca vitulina and northern elephant seals (Mirounga angustirostris and the smooth vibrissae of California sea lions (Zalophus californianus. Vibrations along the whisker shaft were measured in a flume tank, at three orientations (0°, 45°, 90° to the water flow. The results show that vibration frequency and velocity ranges were similar for both undulated and smooth vibrissae. Angle of orientation, rather than surface structure, had the greatest effect on flow-induced vibrations. Vibration velocity was up to 60 times higher when the wide, flat aspect of the whisker faced into the flow (90°, compared to when the thin edge faced into the flow (0°. Vibration frequency was also dependent on angle of orientation. Peak frequencies were measured up to 270 Hz and were highest at the 0° orientation for all whiskers. Furthermore, CT scanning was used to quantify the three-dimensional structure of pinniped vibrissae that may influence flow interactions. The CT data provide evidence that all vibrissae are flattened in cross-section to some extent and that differences exist in the orientation of this profile with respect to the major curvature of the hair shaft. These data support the hypothesis that a compressed cross-sectional profile may play a key role in reducing self

  13. Numerical and experimental investigation of natural flow-induced vibrations of flexible hydrofoils

    Science.gov (United States)

    Chae, Eun Jung; Akcabay, Deniz Tolga; Lelong, Alexandra; Astolfi, Jacques Andre; Young, Yin Lu

    2016-07-01

    The objective of this work is to present combined numerical and experimental studies of natural flow-induced vibrations of flexible hydrofoils. The focus is on identifying the dependence of the foil's vibration frequencies and damping characteristics on the inflow velocity, angle of attack, and solid-to-fluid added mass ratio. Experimental results are shown for a cantilevered polyacetate (POM) hydrofoil tested in the cavitation tunnel at the French Naval Academy Research Institute (IRENav). The foil is observed to primarily behave as a chordwise rigid body and undergoes spanwise bending and twisting deformations, and the flow is observed to be effectively two-dimensional (2D) because of the strong lift retention at the free tip caused by a small gap with a thickness less than the wall boundary layer. Hence, the viscous fluid-structure interaction (FSI) model is formulated by coupling a 2D unsteady Reynolds-averaged Navier-Stokes (URANS) model with a two degree-of-freedom (2-DOF) model representing the spanwise tip bending and twisting deformations. Good agreements were observed between viscous FSI predictions and experimental measurements of natural flow-induced vibrations in fully turbulent and attached flow conditions. The foil vibrations were found to be dominated by the natural frequencies in absence of large scale vortex shedding due to flow separation. The natural frequencies and fluid damping coefficients were found to vary with velocity, angle of attack, and solid-to-fluid added mass ratio. In addition, the numerical results showed that the in-water to in-air natural frequency ratios decreased rapidly, and the fluid damping coefficients increased rapidly, as the solid-to-fluid added mass ratio decreases. Uncoupled mode (UM) linear potential theory was found to significantly over-predict the fluid damping for cases of lightweight flexible hydrofoils, and this over-prediction increased with higher velocity and lower solid-to-fluid added mass ratio.

  14. Segmentation of nanotomographic cortical bone images for quantitative characterization of the osteoctyte lacuno-canalicular network

    Energy Technology Data Exchange (ETDEWEB)

    Ciani, A.; Kewish, C. M. [Synchrotron Soleil, L’Orme des Merisiers, 91192 Saint-Aubin (France); Guizar-Sicairos, M.; Diaz, A.; Holler, M. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Pallu, S.; Achiou, Z.; Jennane, R.; Toumi, H.; Lespessailles, E. [Univ Orléans, I3MTO, Ea 4708, 45000 Orléans (France)

    2016-01-28

    A newly developed data processing method able to characterize the osteocytes lacuno-canalicular network (LCN) is presented. Osteocytes are the most abundant cells in the bone, living in spaces called lacunae embedded inside the bone matrix and connected to each other with an extensive network of canals that allows for the exchange of nutrients and for mechanotransduction functions. The geometrical three-dimensional (3D) architecture is increasingly thought to be related to the macroscopic strength or failure of the bone and it is becoming the focus for investigating widely spread diseases such as osteoporosis. To obtain 3D LCN images non-destructively has been out of reach until recently, since tens-of-nanometers scale resolution is required. Ptychographic tomography was validated for bone imaging in [1], showing clearly the LCN. The method presented here was applied to 3D ptychographic tomographic images in order to extract morphological and geometrical parameters of the lacuno-canalicular structures.

  15. Stress and Alterations in Bones: An Interdisciplinary Perspective

    Directory of Open Access Journals (Sweden)

    Pia-Maria Wippert

    2017-05-01

    Full Text Available Decades of research have demonstrated that physical stress (PS stimulates bone remodeling and affects bone structure and function through complex mechanotransduction mechanisms. Recent research has laid ground to the hypothesis that mental stress (MS also influences bone biology, eventually leading to osteoporosis and increased bone fracture risk. These effects are likely exerted by modulation of hypothalamic–pituitary–adrenal axis activity, resulting in an altered release of growth hormones, glucocorticoids and cytokines, as demonstrated in human and animal studies. Furthermore, molecular cross talk between mental and PS is thought to exist, with either synergistic or preventative effects on bone disease progression depending on the characteristics of the applied stressor. This mini review will explain the emerging concept of MS as an important player in bone adaptation and its potential cross talk with PS by summarizing the current state of knowledge, highlighting newly evolving notions (such as intergenerational transmission of stress and its epigenetic modifications affecting bone and proposing new research directions.

  16. Mechanotransductive Regulation of Gap-Junction Activity Between MLO-Y4 Osteocyte-Like and MC3T3-E1 Osteoblast-Like Cells in Three-Dimensional Co-Culture.

    Science.gov (United States)

    Juran, C. M.; Blaber, E. A.; Almeida, E. A. C.

    2016-01-01

    Cell and animal studies conducted onboard the International Space Station and formerly on Shuttle flights have provided groundbreaking data illuminating the deleterious biological response of bone to mechanical unloading. However the intercellular communicative mechanisms associated with the regulation of bone synthesis and bone resorption cells are still largely unknown. Connexin-43 (CX43), a gap junction protein, is hypothesized to play a significant role in osteoblast and osteocyte signaling. The purpose of this investigation was to evaluate within a novel three-dimensional microenvironment how the osteocyte-osteoblast gap-junction expression changes when cultures are exposed to exaggerated mechanical load. MLO-Y4 osteocyte-like cells were cultured on a 3D-Biotek polystyrene insert and placed in direct contact with an MC3T3-E1 pre-osteoblast co-cultured monolayer and exposed to 48 h of mechanical stimulation (pulsatile fluid flow (PFF) or monolayer cyclic stretch (MCS)) then evaluated for viability, proliferation, metabolism, and CX43 expression. Mono-cultured MLO-Y4 and MC3T3-E1 control experiments were conducted under PFF and MCS stimulation to observe how strain application stimuli (PFF cell membrane shear or MCS cell focal adhesion/attachment loading) initiates different signaling pathways or downstream regulatory controls. TotalLive cell count, viability and metabolic reduction (Trypan Blue, LIVEDead and Alamar Blue analysis respectively) indicate that mechanical activation of MC3T3-E1 cells inhibits proliferation while maintaining an average 1.04E4 reductioncell metabolic rate, *p0.05 n4. MLO-Y4s in monolayer culture increase in number when exposed to MCS loading but the percent of live cells within the population is low (46.3 total count, *p0.05 n4), these results may indicate an apoptotic signaling cascade. PFF stimulation of the three-dimensional co-cultures elicits a universal increase in CX43 in MLO-Y4 and MC3T3-E1 cells, illustrated by

  17. Flow induced particle migration in fresh concrete: Theoretical frame, numerical simulations and experimental results on model fluids

    DEFF Research Database (Denmark)

    Spangenberg, J.; Roussel, N.; Hattel, J.H.

    2012-01-01

    In this paper, we describe and compare the various physical phenomena which potentially lead to flow induced particle migration in concrete. We show that, in the case of industrial casting of concrete, gravity induced particle migration dominates all other potential sources of heterogeneities ind...

  18. Blood and interstitial flow in the hierarchical pore space architecture of bone tissue.

    Science.gov (United States)

    Cowin, Stephen C; Cardoso, Luis

    2015-03-18

    There are two main types of fluid in bone tissue, blood and interstitial fluid. The chemical composition of these fluids varies with time and location in bone. Blood arrives through the arterial system containing oxygen and other nutrients and the blood components depart via the venous system containing less oxygen and reduced nutrition. Within the bone, as within other tissues, substances pass from the blood through the arterial walls into the interstitial fluid. The movement of the interstitial fluid carries these substances to the cells within the bone and, at the same time, carries off the waste materials from the cells. Bone tissue would not live without these fluid movements. The development of a model for poroelastic materials with hierarchical pore space architecture for the description of blood flow and interstitial fluid flow in living bone tissue is reviewed. The model is applied to the problem of determining the exchange of pore fluid between the vascular porosity and the lacunar-canalicular porosity in bone tissue due to cyclic mechanical loading and blood pressure. These results are basic to the understanding of interstitial flow in bone tissue that, in turn, is basic to understanding of nutrient transport from the vasculature to the bone cells buried in the bone tissue and to the process of mechanotransduction by these cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Design and Numerical Simulations of a Flow Induced Vibration Energy Converter for Underwater Mooring Platforms

    Directory of Open Access Journals (Sweden)

    Wenlong Tian

    2017-09-01

    Full Text Available Limited battery energy restricts the duration of the underwater operation of underwater mooring platforms (UMPs. In this paper, a flow-induced vibration energy converter (FIVEC is designed to produce power for the UMPs and extend their operational time. The FIVEC is equipped with a thin plate to capture the kinetic energy in the vortices shed from the surface of the UMP. A magnetic coupling (MC is applied for the non-contacting transmission of the plate torque to the generators so that the friction loss can be minimized. In order to quantify and evaluate the performance of the FIVEC, two-dimensional computational fluid dynamics (CFD simulations are performed. Simulations are based on the Reynolds Averaged Navier-Stokes (RANS equations and the shear stress transport (SST k-ω turbulent model is utilized. The CFD method is firstly validated using existing experimental data. Then the influences of plate length and system damping on the performance of the FIVEC are evaluated. The results show that the device has a maximum averaged power coefficient of 0.0520 (13.86 W in the considered situations. The results also demonstrate the feasibility of this energy converter plan.

  20. Signal analysis of acoustic and flow-induced vibrations of BWR main steam line

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, G., E-mail: gepe@xanum.uam.mx [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Prieto-Guerrero, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Núñez-Carrera, A. [Comisión Nacional de Seguridad Nuclear y Salvaguardias, Doctor Barragán 779, Col. Narvarte, México, D.F. 03020 (Mexico); Vázquez-Rodríguez, A. [División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F. 09340 (Mexico); Centeno-Pérez, J. [Instituto Politécnico Nacional, Escuela Superior de Física y Matemáticas Unidad Profesional “Adolfo López Mateos”, Av. IPN, s/n, México, D.F. 07738 (Mexico); Espinosa-Martínez, E.-G. [Departamento de Sistemas Energéticos, Universidad Nacional Autónoma de México, México, D.F. 04510 (Mexico); and others

    2016-05-15

    Highlights: • Acoustic and flow-induced vibrations of BWR are analyzed. • BWR performance after extended power uprate is considered. • Effect of acoustic side branches (ASB) is analyzed. • The ASB represents a reduction in the acoustic loads to the steam dryer. • Methodology developed for simultaneous analyzing the signals in the MSL. - Abstract: The aim of this work is the signal analysis of acoustic waves due to phenomenon known as singing in Safety Relief Valves (SRV) of the main steam lines (MSL) in a typical BWR5. The acoustic resonance in SRV standpipes and fluctuating pressure is propagated from SRV to the dryer through the MSL. The signals are analyzed with a novel method based on the Multivariate Empirical Mode Decomposition (M-EMD). The M-EMD algorithm has the potential to find common oscillatory modes (IMF) within multivariate data. Based on this fact, we implement the M-EMD technique to find the oscillatory mode in BWR considering the measurements obtained collected by the strain gauges located around the MSL. These IMF, analyzed simultaneously in time, allow obtaining an estimation of the effects of the multiple-SRV in the MSL. Two scenarios are analyzed: the first is the signal obtained before the installation of the acoustic dampers (ASB), and the second, the signal obtained after installation. The results show the effectiveness of the ASB to damp the strong resonances when the steam flow increases, which represents an important reduction in the acoustic loads to the steam dryer.

  1. Debris flow-induced topographic changes: effects of recurrent debris flow initiation.

    Science.gov (United States)

    Chen, Chien-Yuan; Wang, Qun

    2017-08-12

    Chushui Creek in Shengmu Village, Nantou County, Taiwan, was analyzed for recurrent debris flow using numerical modeling and geographic information system (GIS) spatial analysis. The two-dimensional water flood and mudflow simulation program FLO-2D were used to simulate debris flow induced by rainfall during typhoon Herb in 1996 and Mindulle in 2004. Changes in topographic characteristics after the debris flows were simulated for the initiation of hydrological characteristics, magnitude, and affected area. Changes in topographic characteristics included those in elevation, slope, aspect, stream power index (SPI), topographic wetness index (TWI), and hypsometric curve integral (HI), all of which were analyzed using GIS spatial analysis. The results show that the SPI and peak discharge in the basin increased after a recurrence of debris flow. The TWI was higher in 2003 than in 2004 and indicated higher potential of landslide initiation when the slope of the basin was steeper. The HI revealed that the basin was in its mature stage and was shifting toward the old stage. Numerical simulation demonstrated that the parameters' mean depth, maximum depth, affected area, mean flow rate, maximum flow rate, and peak flow discharge were increased after recurrent debris flow, and peak discharge occurred quickly.

  2. Test for Jet Flow Induced by Steam Jet Condensation Using the GIRLS Facility

    International Nuclear Information System (INIS)

    Kim, Yeon Sik; Yoon, Y. J.; Song, C. H.

    2007-03-01

    To investigate the characteristics of the turbulent jet induced by steam jet condensation in a water tank through a single-hole sparger an experimental investigation was performed using the GIRLS facility. The experiments were conducted with respect to two cases, e.g. horizontal and vertical upward injections. For the measurements, pitot tube and thermocouples were used for turbulent flow velocity and temperatures, respectively. Overall flow shapes of the turbulent jet by the steam jet condensation are similar to those of axially symmetric turbulent jet flows. The angular coefficients of turbulent rays are quantitatively comparable between the traditional turbulent jet flows and the turbulent jet flows induced by the steam jet condensation in this work. Although the turbulent flows were induced by the horizontally injected steam jet condensation, general theory of turbulent jets was found to be applicable to the turbulent flows of this work. But for the vertically upward injection case, experimental data were quite deviated from the theoretical ones, which is considered due to the buoyancy effect

  3. Flow Induced by Ex-Vivo Nasal Cilia: Developing an Index of Dyskinesis

    Science.gov (United States)

    Grotberg, James; Bottier, Mathieu; Pena-Fernandez, Marta; Blanchon, Sylvain; Pelle, Gabriel; Bequignon, Emilie; Isabey, Daniel; Coste, Andre; Escudier, Estelle; Papon, Jean-Francois; Filoche, Marcel; Louis, Bruno

    2017-11-01

    Mucociliary clearance is one of the major lines of defense of the respiratory system. The mucus layer coating the pulmonary airways is moved along and out of the lung by the activity of motile cilia, thus expelling the particles trapped in it. Here we compare ex vivomeasurements of a Newtonian flow induced by cilia beating (using micro-beads as tracers) and a mathematical model of this fluid flow. Samples of nasal epithelial cells placed in water are recorded by high-speed video-microscopy and ciliary beat pattern is inferred. Automatic tracking of micro-beads, used as markers of the flow generated by cilia motion, enables us also to assess the steady velocity profile as a function of the distance above the cilia. This profile is shown to be essentially parabolic. This compares well to a 2D mathematical model for ciliary fluid propulsion using an envelope model. From the model and the experimental measurements, the shear stress exerted by the cilia is deduced. Finally, this shear stress is proposed as a new index for characterizing the efficiency of ciliary beating and diagnosing dyskinesis.

  4. Modeling fluid forces and response of a tube bundle in cross-flow induced vibrations

    International Nuclear Information System (INIS)

    Khushnood, Shahab; Khan, Zaffar M.; Malik, M. Afzaal; Koreshi, Zafarullah; Khan, Mahmood Anwar

    2003-01-01

    Flow induced vibrations occur in process heat exchangers, condensers, boilers and nuclear steam generators. Under certain flow conditions and fluid velocities, the fluid forces result in tube vibrations and possible damage of tube, tube sheet or baffle due to fretting and fatigue. Prediction of these forces is an important consideration. The characteristics of vibration depend greatly on the fluid dynamic forces and structure of the tube bundle. It is undesirable for the tube bundles to vibrate excessively under normal operating conditions because tubes wear and eventual leakage can occur leading to costly shutdowns. In this paper modeling of fluid forces and vibration response of a tube in a heat exchanger bundle has been carried out. Experimental validation has been performed on an existing refinery heat exchanger tube bundle. The target tube has been instrumented with an accelerometer and strain gages. The bundle has been studied for pulse, sinusoidal and random excitations. Natural frequencies and damping of the tubes have also been computed. Experimental fluid forces and response shows a reasonable agreement with the predictions. (author)

  5. Physical and numerical investigation of the flow induced vibration of the hydrofoil

    Science.gov (United States)

    Wu, Q.; Wang, G. Y.; Huang, B.

    2016-11-01

    The objective of this paper is to investigate the flow induced vibration of a flexible hydrofoil in cavitating flows via combined experimental and numerical studies. The experiments are presented for the modified NACA66 hydrofoil made of POM Polyacetate in the closed-loop cavitation tunnel at Beijing Institute of Technology. The high-speed camera and the single point Laser Doppler Vibrometer are applied to analyze the transient flow structures and the corresponding structural vibration characteristics. The hybrid coupled fluid structure interaction model is conducted to couple the incompressible and unsteady Reynolds Averaged Navier-Stokes solver with a simplified two-degree-of-freedom structural model. The k-ω SST turbulence model with the turbulence viscosity correction and the Zwart cavitation model are introduced to the present simulations. The results showed that with the decreasing of the cavitation number, the cavitating flows display incipient cavitation, sheet cavitation, cloud cavitation and supercavitation. The vibration magnitude increases dramatically for the cloud cavitation and decline for the supercavitation. The cloud cavitation development strongly affects the vibration response, which is corresponding to the periodically developing and shedding of the large-scale cloud cavity. The main frequency of the vibration amplitude is accordance with the cavity shedding frequency and other two frequencies of the vibration amplitude are corresponding to the natural frequencies of the bending and twisting modes.

  6. FLOW-INDUCED VIBRATION IN PIPES: CHALLENGESS AND SOLUTIONS - A REVIEW

    Directory of Open Access Journals (Sweden)

    M. SIBA

    2016-03-01

    Full Text Available The Flow-induced vibration has recently been the topic of experimental, numerical, and theoretical studies. It was intended to implement better applications for controlling the flow using orifice technique. Having the flow under control, the orifice becomes an instrument for measuring the flow. The flow of all fluid such as water, oil, gas and vapours through an orifice was tested and mathematical models were developed adequately. The basic theme for these enormous studies was the need for the very accurate flow measurements through orifices. All experimental, theoretical, numerical, and analytical studies have agreed that there is more than one avenue to develop, modify, and enhance such measurements. However, one factor that affects the flow measurements is the vibration which was not treated as required until the mid-20th century due to enormous discoveries that damages could be rooted to vibration. Researchers have studied vibration and then proposed mathematical models in conjunction with the pressure and velocity measurements of the flowing fluids and then the effect of the vibration, induced or not induced, has been under continuous investigation. This paper is an attempt to review the previous studies regarding understanding the nature of the vibration and the possible effects of vibration on the flow and on the piping structure in order to limit the damage caused by the vibration. This study shows that the need for more experimental studies and more comprehensive analytical approaches are, in particular, very essential to develop better results.

  7. Experimental investigation of flow-induced control-element movements by noise analysis

    International Nuclear Information System (INIS)

    Grunwald, G.; Liewers, P.; Schumann, P.; Weiss, F.P.

    1978-01-01

    The possibility has been reported of separating a single noise component due to flow-induced vibrations of a certain control element from a complex neutron signal which also contained contributions of many other control elements vibrating similarly. One of the basic assumptions for the different methods applied was that the body sound signal originating from touch events with the channel wall is closely correlated with the control-element movement. Some discrepancies between the results of the different methods showed that this assumption may not be entirely fulfilled. This paper investigates this correlation more accurately by measurements of an air flow model of the control-element channel. The pendulum movement of the element, and the body-sound signal due to the touch events with the channel wall, were measured at different flow-rates. The result is that the correlation is not an ideal one. For a constant flow-rate the touch events happen mainly within a small angle region, which means that the touch event marks a certain phase of the movement period and is therefore correlated with the movement. The dispersion of the touch events' angle distribution explains the small discrepancy between the so-called modified averaging method, which uses the sound signal to trigger the averaging procedure, and the partial spectral density method. But not all discrepancies can be explained by these results; they await further investigation. (author)

  8. Flow-induced vibration analysis of a helical coil steam generator experiment using large eddy simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Haomin; Solberg, Jerome; Merzari, Elia; Kraus, Adam; Grindeanu, Iulian

    2017-10-01

    This paper describes a numerical study of flow-induced vibration in a helical coil steam generator experiment conducted at Argonne National Laboratory in the 1980s. In the experiment, a half-scale sector model of a steam generator helical coil tube bank was subjected to still and flowing air and water, and the vibrational characteristics were recorded. The research detailed in this document utilizes the multi-physics simulation toolkit SHARP developed at Argonne National Laboratory, in cooperation with Lawrence Livermore National Laboratory, to simulate the experiment. SHARP uses the spectral element code Nek5000 for fluid dynamics analysis and the finite element code DIABLO for structural analysis. The flow around the coil tubes is modeled in Nek5000 by using a large eddy simulation turbulence model. Transient pressure data on the tube surfaces is sampled and transferred to DIABLO for the structural simulation. The structural response is simulated in DIABLO via an implicit time-marching algorithm and a combination of continuum elements and structural shells. Tube vibration data (acceleration and frequency) are sampled and compared with the experimental data. Currently, only one-way coupling is used, which means that pressure loads from the fluid simulation are transferred to the structural simulation but the resulting structural displacements are not fed back to the fluid simulation

  9. Flow induced by ependymal cilia dominates near-wall cerebrospinal fluid dynamics in the lateral ventricles.

    Science.gov (United States)

    Siyahhan, Bercan; Knobloch, Verena; de Zélicourt, Diane; Asgari, Mahdi; Schmid Daners, Marianne; Poulikakos, Dimos; Kurtcuoglu, Vartan

    2014-05-06

    While there is growing experimental evidence that cerebrospinal fluid (CSF) flow induced by the beating of ependymal cilia is an important factor for neuronal guidance, the respective contribution of vascular pulsation-driven macroscale oscillatory CSF flow remains unclear. This work uses computational fluid dynamics to elucidate the interplay between macroscale and cilia-induced CSF flows and their relative impact on near-wall dynamics. Physiological macroscale CSF dynamics are simulated in the ventricular space using subject-specific anatomy, wall motion and choroid plexus pulsations derived from magnetic resonance imaging. Near-wall flow is quantified in two subdomains selected from the right lateral ventricle, for which dynamic boundary conditions are extracted from the macroscale simulations. When cilia are neglected, CSF pulsation leads to periodic flow reversals along the ventricular surface, resulting in close to zero time-averaged force on the ventricle wall. The cilia promote more aligned wall shear stresses that are on average two orders of magnitude larger compared with those produced by macroscopic pulsatile flow. These findings indicate that CSF flow-mediated neuronal guidance is likely to be dominated by the action of the ependymal cilia in the lateral ventricles, whereas CSF dynamics in the centre regions of the ventricles is driven predominantly by wall motion and choroid plexus pulsation.

  10. Flow-induced vibration characteristics of the BWR/5-201 jet pump

    International Nuclear Information System (INIS)

    LaCroix, L.V.

    1982-09-01

    A General Electric boiling water reactor BWR/5-201 jet pump was tested for flow-induced vibration (FIV) characteristics in the Large Steam Water Test Facility at Moss Landing, CA, during the period June-July 1978. High level periodic FIV were observed at reactor operating conditions (1027 psia, 532 0 F and prototypical flow rates) for the specific single jet pump assembly tested. High level FIV of similar amplitude and character have been shown capable of damaging jet pump components and associated support hardware if allowed to continue unchecked. High level FIV were effectively suppressed in two special cases tested: (1) lateral load (>500 lb) at the mixer to diffuser slip joint; and (2) a labyrinth seal (5 small, circumferential grooves) on the mixer at the slip joint. Stability criteria for the particular jet pump tested were developed from test data. A cause-effect relationship between the dynamic pressure within the slip joint and the jet pump vibration was established

  11. Translational Optic Flow Induces Shifts in Direction of Active Forward and Backward Self-Motion

    Directory of Open Access Journals (Sweden)

    Kenzo Sakurai

    2011-05-01

    Full Text Available Previously, we reported that when observers passively experience real linear oscillatory somatic motion while viewing orthogonal visual optic flow patterns, their perceived motion direction is intermediate to those specified by visual and vestibular information individually (Sakurai et al., 2002, ACV; 2003, ECVP; 2010, VSS; Kubodera et al., 2010, APCV. Here, we extend those studies to active somatic motion, measuring the angular shift in body direction after active body motion while viewing synchronized orthogonal optic flow. Experimental visual stimuli consisted of 1 second of translating leftward (rightward random-dots and 1 second of random noise. Control stimuli consisted of two 1-second intervals of random noise separated by a static interval. Observers viewed the stimulus for 30 seconds through a face-mounted display while actively stepping forward and backward such that their forward body movement was synchronized with the random-dot translational motion. Observers' body direction was measured before and after each trial. Translational optic flow induced shifts in body direction that were opposite to shifts in perceived direction with passive viewing in our previous reports. Observers may have compensated their body motion in response to perceived direction shifts similar to those we reported for passive viewing.

  12. Investigation of flow-induced vibration for energy harvesting using a model soap-film system

    Science.gov (United States)

    Yang, Wenchao; Stremler, Mark; Virginia Tech Team

    2017-11-01

    One way to extract energy from geophysical flows is to take advantage of flow-induced vibration (FIV) caused by vortices being shed from a bluff body. Wake-induced vibration of the downstream cylinder in a tandem pair is a promising design for a FIV energy harvesting system, especially suitable for low Reynolds number flows. For this design, the upstream cylinder is fixed in place, while the downstream cylinder is free to oscillate like a pendulum that is driven by interactions with the flow, including the wake of the upstream cylinder. We use a flowing soap film system, with behavior that resembles two-dimensional hydrodynamics, to experimentally investigate the wake interaction between a stationary upstream circular disk and a free downstream circular disk, which acts as a swinging pendulum. The wake flow generates thickness variations in the thin soap film, allowing direct observation of wake patterns through visualization of interference fringes. With the ability to tie together the wake structure and the object motion, we investigate the relationship between energy generation and flow structure in the simplified model energy harvesting system for Re =150. The research results find the optimal efficiency of the energy harvesting system by a parametric study.

  13. Parametric Study and Optimization of a Piezoelectric Energy Harvester from Flow Induced Vibration

    Science.gov (United States)

    Ashok, P.; Jawahar Chandra, C.; Neeraj, P.; Santhosh, B.

    2018-02-01

    Self-powered systems have become the need of the hour and several devices and techniques were proposed in favour of this crisis. Among the various sources, vibrations, being the most practical scenario, is chosen in the present study to investigate for the possibility of harvesting energy. Various methods were devised to trap the energy generated by vibrating bodies, which would otherwise be wasted. One such concept is termed as flow-induced vibration which involves the flow of a fluid across a bluff body that oscillates due to a phenomenon known as vortex shedding. These oscillations can be converted into electrical energy by the use of piezoelectric patches. A two degree of freedom system containing a cylinder as the primary mass and a cantilever beam as the secondary mass attached with a piezoelectric circuit, was considered to model the problem. Three wake oscillator models were studied in order to determine the one which can generate results with high accuracy. It was found that Facchinetti model produced better results than the other two and hence a parametric study was performed to determine the favourable range of the controllable variables of the system. A fitness function was formulated and optimization of the selected parameters was done using genetic algorithm. The parametric optimization led to a considerable improvement in the harvested voltage from the system owing to the high displacement of secondary mass.

  14. Preparation of Nanostructured Microporous Metal Foams through Flow Induced Electroless Deposition

    Directory of Open Access Journals (Sweden)

    Galip Akay

    2015-01-01

    Full Text Available Monolithic nanostructured metallic porous structures with a hierarchy of pore size ranging from ca. 10 μm to 1 nm are processed for use as microreactors. The technique is based on flow induced electroless deposition of metals on a porous template known as PolyHIPE Polymer. The process is conducted in a purpose built flow reactor using a processing protocol to allow uniform and efficient metal deposition under flow. Nickel chloride and sodium hypophosphite were used as the metal and reducing agent, respectively. Electroless deposition occurs in the form of grains with a composition of NixPy in which the grain size range was ca. 20–0.2 μm depending on the composition of the metal deposition solution. Structure formation in the monoliths starts with heat treatment above 600°C resulting in the formation of a 3-dimensional network of capillary-like porous structures which form the walls of large arterial pores. These monoliths have a dense but porous surface providing mechanical strength for the monolith. The porous capillary-like arterial pore walls provide a large surface area for any catalytic activity. The mechanisms of metal deposition and nanostructure formation are evaluated using scanning electron microscopy, energy dispersive X-ray analysis, XRD, BET-surface area, and mercury intrusion porosimetry.

  15. A visualization study of flow-induced acoustic resonance in a branched pipe

    International Nuclear Information System (INIS)

    Li, Yanrong; Someya, Satoshi; Okamoto, Koji

    2008-01-01

    Systems with closed side-branches are liable to an excitation of sound, as called cavity tones. It may occur in pipe branches leading to safety valves or to boiler relief valves. The outbreak mechanism of the cavity tone has been known by phase-averaged measurement in previous researches, while the relation between sound propagation and flow field is still unclear due to the difficulty of detecting instantaneous pressure field. High time-resolved PIV has a possibility to analyze the pressure field and the relation mentioned above. In this report, flow-induced acoustic resonances of piping system containing closed side-branches were investigated experimentally. A High-Time-Resolved PIV technique was applied to measure a gas-flow in a cavity-tone. Air flow containing an oil mist as tracer particles was measured using a high frequency pulse laser and a high-speed camera. The present investigation on the coaxial closed side-branches is the first rudimentary study to measure the flow field two-dimensionally and simultaneously with the pressure measurement at multi-points and to visualize the fluid flow in the cross-section by using PIV. The fluid flows at different points in the cavity interact with some phase differences and the relation should be clarified. (author)

  16. Flow induced by ependymal cilia dominates near-wall cerebrospinal fluid dynamics in the lateral ventricles

    Science.gov (United States)

    Siyahhan, Bercan; Knobloch, Verena; de Zélicourt, Diane; Asgari, Mahdi; Schmid Daners, Marianne; Poulikakos, Dimos; Kurtcuoglu, Vartan

    2014-01-01

    While there is growing experimental evidence that cerebrospinal fluid (CSF) flow induced by the beating of ependymal cilia is an important factor for neuronal guidance, the respective contribution of vascular pulsation-driven macroscale oscillatory CSF flow remains unclear. This work uses computational fluid dynamics to elucidate the interplay between macroscale and cilia-induced CSF flows and their relative impact on near-wall dynamics. Physiological macroscale CSF dynamics are simulated in the ventricular space using subject-specific anatomy, wall motion and choroid plexus pulsations derived from magnetic resonance imaging. Near-wall flow is quantified in two subdomains selected from the right lateral ventricle, for which dynamic boundary conditions are extracted from the macroscale simulations. When cilia are neglected, CSF pulsation leads to periodic flow reversals along the ventricular surface, resulting in close to zero time-averaged force on the ventricle wall. The cilia promote more aligned wall shear stresses that are on average two orders of magnitude larger compared with those produced by macroscopic pulsatile flow. These findings indicate that CSF flow-mediated neuronal guidance is likely to be dominated by the action of the ependymal cilia in the lateral ventricles, whereas CSF dynamics in the centre regions of the ventricles is driven predominantly by wall motion and choroid plexus pulsation. PMID:24621815

  17. Flow-induced vibration for light water reactors. Progress report, January-June 1980

    International Nuclear Information System (INIS)

    De Coster, M.A.

    1981-02-01

    Flow-Induced Vibration for Light Water Reactors (FIV for LWRs) is a four-year program designed to improve the FIV performance of light water reactors through the development of design criteria, analytical models for predicting behavior of components, general scaling laws to improve the accuracy of reduced-scale tests, and the identification of high FIV risk areas. The program is managed by the General Electric Nuclear Power Systems Engineering Department and has three major contributors: General Electric Nuclear Power Systems Engineering Department (NPSED), General Electric Corporate Research and Development (CR and D) and Argonne National Laboratory (ANL). The program commenced December 1, 1976, but was suspended on September 30, 1978, due to a shift in Department of Energy (DOE) priorities away from LWR productivity/availability. It was reinitiated as of August 1, 1979. A second program suspension occurred from March 29, 1980 through May 16, 1980, due to funding limits. This progress report summarizes the accomplishments achieved during the period from Janury 1980 to June 1980

  18. Flow-induced vibration study by exploiting inherent nonlinearity of structure

    Science.gov (United States)

    Seyed-Aghazadeh, Banafsheh; Samandari, Hamed

    2017-11-01

    Elastically mounted prismatic structures placed in flow can undergo Flow-Induced Vibration (FIV). Flow forces acting on these structures consist of a main frequency, close to the natural frequency of the system, as well as its higher harmonic components. Mostly in FIV studies, the structural stiffness is provided through linear springs. The linearity of the structure limits occurrence of potential large amplitude oscillations at higher harmonics of the main frequency. In this study, we propose implementing an inherently nonlinear structure in FIV study of a prismatic structure. Through this unique design, excitation of higher harmonics and coupling between those and natural frequencies of the system can be achieved. A square cross-section prism was mounted on the upstream tip of an elastic beam with inherent nonlinearity and was placed in the test-section of a subsonic wind tunnel. The tests were conducted in a Reynolds number range of 150

  19. Diabetes alters vascular mechanotransduction data: Pressure-induced regulation of mTor and associated signaling in the rat inferior vena cava

    Directory of Open Access Journals (Sweden)

    Kevin M. Rice

    2017-12-01

    Full Text Available Diabetes is a multifaceted disease with various etiologies. The complexity of this pathology creates a myriad of factors that must be considered when addressing surgical outcomes and prognosis. Of vital importance to cardiovascular surgery is the viability of homographic vein grafts. Due to the fact, diabetic patients have a higher rate of vein graph failure, a greater understanding of the effect diabetes has on vascular mechano-transductive response is critical to improving patient prognosis. This article represents data regarding a study published in Cardiovascular Diabetology (Rice et al., 2006 [1] and Open Journal of Endocrine and Metabolic Diseases (Rice et al., 2015 [2] with the purpose of evaluating the effect of pressurization on rat inferior venae cavae (IVC. Here we provide the information about the method and processing of raw data related to our prior publish work and Data in Brief articles (Rice et al., Submitted for publication [3,4]. The data contained in this article evaluates the contribution of mTor signaling and associated proteins. IVC from lean and obese animals were exposed to a 30 min perfusion of 120 mm Hg pressure and evaluated for changes in expression and phosphorylation of mTor, p70s6k, GSK3β, and 4EBP-1. Keywords: Inferior vena cava, Diabetes, mTor, Mechanotransduction, Cardiovascular, Signaling

  20. Adding dimension to cellular mechanotransduction: Advances in biomedical engineering of multiaxial cell-stretch systems and their application to cardiovascular biomechanics and mechano-signaling.

    Science.gov (United States)

    Friedrich, O; Schneidereit, D; Nikolaev, Y A; Nikolova-Krstevski, V; Schürmann, S; Wirth-Hücking, A; Merten, A L; Fatkin, D; Martinac, B

    2017-11-01

    Hollow organs (e.g. heart) experience pressure-induced mechanical wall stress sensed by molecular mechano-biosensors, including mechanosensitive ion channels, to translate into intracellular signaling. For direct mechanistic studies, stretch devices to apply defined extensions to cells adhered to elastomeric membranes have stimulated mechanotransduction research. However, most engineered systems only exploit unilateral cellular stretch. In addition, it is often taken for granted that stretch applied by hardware translates 1:1 to the cell membrane. However, the latter crucially depends on the tightness of the cell-substrate junction by focal adhesion complexes and is often not calibrated for. In the heart, (increased) hemodynamic volume/pressure load is associated with (increased) multiaxial wall tension, stretching individual cardiomyocytes in multiple directions. To adequately study cellular models of chronic organ distension on a cellular level, biomedical engineering faces challenges to implement multiaxial cell stretch systems that allow observing cell reactions to stretch during live-cell imaging, and to calibrate for hardware-to-cell membrane stretch translation. Here, we review mechanotransduction, cell stretch technologies from uni-to multiaxial designs in cardio-vascular research, and the importance of the stretch substrate-cell membrane junction. We also present new results using our IsoStretcher to demonstrate mechanosensitivity of Piezo1 in HEK293 cells and stretch-induced Ca 2+ entry in 3D-hydrogel-embedded cardiomyocytes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Bone Cancer

    Science.gov (United States)

    Cancer that starts in a bone is uncommon. Cancer that has spread to the bone from another ... more common. There are three types of bone cancer: Osteosarcoma - occurs most often between ages 10 and ...

  2. Proceedings of the 8. international conference on Flow-induced vibration

    International Nuclear Information System (INIS)

    Langre, E. de; Axisa, F.

    2004-01-01

    FIV2004, the eighth of the series of International Conferences on Flow-Induced Vibration initiated at Keswick in 1973, evidences the sustained interest of the scientific and engineering international community for a subject area which incorporates at least two major disciplines: fluid mechanics and structural dynamics. Flow induced vibration (FIV) occur whenever a structure is in contact with a flowing fluid; which is a very common occurrence indeed. FIV can be rightly perceived as very useful and agreeable, in musical instruments, or at the opposite as annoying and even disastrous, in mechanical engineering. In both cases, the subject motivates a large and highly diversified amount of research work, driven either by scientific curiosity or engineering concerns, or both. In this field, empirical knowledge and experience are a precious asset but a certain breadth of perspective gained through a thorough background in theoretical mechanics is also necessary. In other words, to deal successfully with FIV problems, theoretical and pragmatic knowledge must be skillfully interwoven. Having also in mind the impressive progress achieved since the early seventies both in experimental techniques and computer science, it is rather fascinating to realize that we have still to learn so much about so 'elementary' systems as a pipe conveying air or water, or cylindrical rods subjected to cross-flow, to mention just two archetypical systems which are in fact extremely complex and which motivated so many studies already at the time of the first Keswick Conference and which still do at FIV2004. Though such systems are encountered in many industrial components and are rather easily accessible to experiment, they still give rise to many challenging questions concerning the extremely varied dynamical behavior they can display, which remain often insufficiently amenable to prediction. By no means this is to say that the research work devoted to FIV up to now has been made in vain. First

  3. Effects of flow-induced shear stress on limbal epithelial stem cell growth and enrichment.

    Directory of Open Access Journals (Sweden)

    Yun Gyeong Kang

    Full Text Available The roles of limbal epithelial stem cells (LESCs are widely recognized, but for these cells to be utilized in basic research and potential clinical applications, researchers must be able to efficiently isolate them and subsequently maintain their stemness in vitro. We aimed to develop a biomimetic environment for LESCs involving cells from their in vivo niche and the principle of flow-induced shear stress, and to subsequently demonstrate the potential of this novel paradigm. LESCs, together with neighboring cells, were isolated from the minced limbal tissues of rabbits. At days 8 and 9 of culture, the cells were exposed to a steady flow or intermittent flow for 2 h per day in a custom-designed bioreactor. The responses of LESCs and epithelial cells were assessed at days 12 and 14. LESCs and epithelial cells responded to both types of flow. Proliferation of LESCs, as assessed using a BrdU assay, was increased to a greater extent under steady flow conditions. Holoclones were found under intermittent flow, indicating that differentiation into transient amplifying cells had occurred. Immunofluorescent staining of Bmi-1 suggested that steady flow has a positive effect on the maintenance of stemness. This finding was confirmed by real-time PCR. Notch-1 and p63 were more sensitive to intermittent flow, but this effect was transient. K3 and K12 expression, indicative of differentiation of LESCs into epithelial cells, was induced by flow and lasted longer under intermittent flow conditions. In summary, culture of LESCs in a bioreactor under a steady flow paradigm, rather than one of intermittent flow, is beneficial for both increasing proliferation and maintaining stemness. Conversely, intermittent flow appears to induce differentiation of LESCs. This novel experimental method introduces micro-mechanical stimuli to traditional culture techniques, and has potential for regulating the proliferation and differentiation of LESCs in vitro, thereby

  4. Effects of flow-induced shear stress on limbal epithelial stem cell growth and enrichment.

    Science.gov (United States)

    Kang, Yun Gyeong; Shin, Ji Won; Park, So Hee; Oh, Min-Jae; Park, Hyo Soon; Shin, Jung-Woog; Kim, Su-Hyang

    2014-01-01

    The roles of limbal epithelial stem cells (LESCs) are widely recognized, but for these cells to be utilized in basic research and potential clinical applications, researchers must be able to efficiently isolate them and subsequently maintain their stemness in vitro. We aimed to develop a biomimetic environment for LESCs involving cells from their in vivo niche and the principle of flow-induced shear stress, and to subsequently demonstrate the potential of this novel paradigm. LESCs, together with neighboring cells, were isolated from the minced limbal tissues of rabbits. At days 8 and 9 of culture, the cells were exposed to a steady flow or intermittent flow for 2 h per day in a custom-designed bioreactor. The responses of LESCs and epithelial cells were assessed at days 12 and 14. LESCs and epithelial cells responded to both types of flow. Proliferation of LESCs, as assessed using a BrdU assay, was increased to a greater extent under steady flow conditions. Holoclones were found under intermittent flow, indicating that differentiation into transient amplifying cells had occurred. Immunofluorescent staining of Bmi-1 suggested that steady flow has a positive effect on the maintenance of stemness. This finding was confirmed by real-time PCR. Notch-1 and p63 were more sensitive to intermittent flow, but this effect was transient. K3 and K12 expression, indicative of differentiation of LESCs into epithelial cells, was induced by flow and lasted longer under intermittent flow conditions. In summary, culture of LESCs in a bioreactor under a steady flow paradigm, rather than one of intermittent flow, is beneficial for both increasing proliferation and maintaining stemness. Conversely, intermittent flow appears to induce differentiation of LESCs. This novel experimental method introduces micro-mechanical stimuli to traditional culture techniques, and has potential for regulating the proliferation and differentiation of LESCs in vitro, thereby facilitating research in this

  5. Experimental study on flow-induced vibration of propeller blades under non-uniform inflow

    Directory of Open Access Journals (Sweden)

    LI Jing

    2017-12-01

    Full Text Available [Objectives] This article presents an experimental study of the flow-induced vibration of propeller blades under periodic inflow, and the dependence of the response on its modes.[Methods] Two seven-bladed highly skewed model propellers of identical proportions but different material are operated in four-cycle and six-cycle inflows to produce a blade vibratory strain response. Two kinds of wire mesh wake screens located 400 mm upstream of the propeller plane are used to generate the four-cycle and six-cycle inflows. A laser Doppler velocimetry system located 100 mm downstream of the wake screen plane is used to measure the axial velocity distributions produced by the wake screens. Strain gauges are attached to the propeller blades at different positions. The data from the strain gauges quantifies the excitation frequencies induced by the wake screens. It is shown that the response will reach peak axial propeller frequency, four times axial propeller frequency and six times axial propeller frequency under uniform inflow, four-cycle inflow and six-cycle inflow respectively.[Results] The effect of resonance on the vibratory strain response is revealed. When six times axial propeller frequency induced by six-cycle inflow coincides with the natural frequency of a flexible propeller, the response of the propeller is at its greatest.[Conclusions] This research reveals that when designing a propeller, it is not sufficient to only focus on its hydrodynamic properties; the effects of the modes of the propeller should also be considered.

  6. Flow induced motion and energy harvesting of bluff bodies with different cross sections

    International Nuclear Information System (INIS)

    Ding, Lin; Zhang, Li; Wu, Chunmei; Mao, Xinru; Jiang, Deyi

    2015-01-01

    Highlights: • Code for FIM and power harvesting of different cross-section cylinders is developed. • VIV appears combined with galloping for PTC-cylinder and quasi-trapezoid cylinder. • Vortex structures of cylinder in VIV and galloping are predicted accurately. • Power can be harnessed over the high-lift TrSL3 regime when Re > 30,000. - Abstract: The flow induced motion (FIM) and energy conversion of cylinders with different cross sections are investigated using two-dimensional unsteady Reynolds-Averaged Navier–Stokes simulations in the Reynolds number range of 10,000 < Re < 130,000. The model for energy harvesting in FIM is established and verified by experimental measurements. For the PTC-cylinder (circular cylinder with passive turbulence control), square cylinder, Q-trapezoid I (quasi-trapezoid cylinder with the long edge as the windward side), and triangular prism, energy can be obviously harvested when Re > 30,000. The initial and upper branches of vortex induced vibration (VIV), transition from VIV to galloping, and galloping branch are clearly observed in the amplitude and frequency responses. The FIM responses of PTC-cylinder and Q-trapezoid I are stronger than the other cylinders. The maximum amplitude of 3.5D is achieved and 16 vortices are captured in one cycle in the fully-developed galloping branch. The optimum regime for energy harvesting is the VIV upper branch. And the PTC-cylinder and Q-trapezoid I have better performance on energy harvesting in FIM than other cylinders. The maximum energy efficiencies of 45.7% and 37.9% are achieved for Q-trapezoid I and PTC-cylinder respectively. Contrarily, the vibration of Q-trapezoid II (quasi-trapezoid cylinder with the short edge as the windward side) displays a quite different character with low amplitude and high frequency, and the vortex pattern is a constant 2S in the test Re range

  7. Flow-induced vibration for light water reactors. Progress report, December 1976--May 1977

    International Nuclear Information System (INIS)

    Schardt, J.

    1977-09-01

    The report describes the program objectives, overall work plans, and progress achieved. A description is also given of the related state-of-the-art flow-induced vibration (FIV) technology which represents the starting point of the program. The program has been developed to increase plant availability through substantially reducing downtime caused by FIV failure of components. It is a four-year balanced effort of fundamental studies, analyses, tests of idealized conditions, and realistic tests of reactor components, all leading to the preparation of design guides and criteria for LWR's. The specific goals of the program are to: (1) produce improved FIV design criteria; (2) provide improved analytical methods for predicting behavior of components; (3) provide general scaling laws which will improve the accuracy of reduced-scale tests (required for those situations where it is impossible to predict the FIV response analytically or through full-scale testing); and (4) identify high FIV risk areas. To achieve these goals, the program has been divided into four major tasks: (1) fundamental studies; (2) model and full-size tests; (3) design methods, guides and criteria; and (4) program administration. Task 1 will provide a better understanding of FIV phenomena through a combination of fundamental tests and analyses of geometries common in LWR's and mechanisms which can cause FIV. The studies will systematically vary parameters using relatively small-scale idealized geometries and controlled flow fields. Task 2 will verify and extend the results of Task 1 through the testing of realistic LWR component geometries. Task 3 will develop analytical methods, as well as utilize the results of Tasks 1 and 2 to produce design guides, predictive models, and scaling laws. Task 4 will administrate the program, as well as insure that pressure water reactor (PWR) needs are given proper consideration

  8. Numerical investigation on flow-induced vibration of a triangular cylinder at a low Reynolds number

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huakun; Zhao, Dongliang; Yang, Wenyu; Yu, Guoliang, E-mail: yugl@sjtu.edu.cn [State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, People’s Republic of China (China)

    2015-02-01

    Flow-induced vibration (FIV) of a triangular cylinder is numerically investigated at a Reynolds number of Re = 100. The four-step fractional finite element method is employed to solve the two-dimensional (2D) incompressible Navier–Stokes equations. The cylinder is endowed with a two-degree-of-freedom motion with the reduced mass ratio of M{sub r} = 2. Three typical flow incidence angles, α = 0°, 30° and 60°, are examined to identify the effect of incidence angle on the vibration characteristics of the cylinder. For each α, computations are conducted in a wide range of reduced velocities 2 U{sub r} ≤ 18. The numerical results show that at α = 0° and 30°, the responses of the cylinder are dominated by vortex-induced vibration which resembles that of a circular cylinder. At α = 0°, the peak amplitude of transverse vibration is the smallest among the three investigated α, and most of the cylinder motions exhibit a regular figure-eight trajectory. Some single-loop trajectories are observed at α = 30°, where the vibration frequency in the in-line direction is always identical to that in the transverse direction. At α = 60°, the triangular cylinder undergoes a typical transverse galloping with large amplitude and low frequency, and the vibration trajectories appear to be regular or irregular figure-eight patterns, which are strongly affected by the reduced velocity. (paper)

  9. Mechanotransduction and the Cytoskeleton

    Science.gov (United States)

    Pickard, Barbara G.

    1996-01-01

    Two intellectual developments in the lab suggested a more powerful approach to the problem defined in the original statement. These were discussed with the "Program Chief', who agreed that an alteration of approach was desirable. Second expansion of our work was on the computational optical sectioning microscope (COSM). Additionally, we hoped to visualize the channels with respect to cytoskeletal entities. We have identified major here-to-fore unknown cytoskeletal structure in our representative experimental system, the onion epidermal cell, and have named this structure the endomembrane grant.

  10. Low Bone Density

    Science.gov (United States)

    ... Bone Density Exam/Testing › Low Bone Density Low Bone Density Low bone density is when your bone ... to people with normal bone density. Detecting Low Bone Density A bone density test will determine whether ...

  11. A Phase Field Technique for Modeling and Predicting Flow Induced Crystallization Morphology of Semi-Crystalline Polymers

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2016-06-01

    Full Text Available Flow induced crystallization of semi-crystalline polymers is an important issue in polymer science and engineering because the changes in morphology strongly affect the properties of polymer materials. In this study, a phase field technique considering polymer characteristics was established for modeling and predicting the resulting morphologies. The considered crystallization process can be divided into two stages, which are nucleation upon the flow induced structures and subsequent crystal growth after the cessation of flow. Accordingly, the proposed technique consists of two parts which are a flow induced nucleation model based on the calculated information of molecular orientation and stretch, and a phase field crystal growth model upon the oriented nuclei. Two-dimensional simulations are carried out to predict the crystallization morphology of isotactic polystyrene under an injection molding process. The results of these simulations demonstrate that flow affects crystallization morphology mainly by producing oriented nuclei. Specifically, the typical skin-core structures along the thickness direction can be successfully predicted. More importantly, the results reveal that flow plays a dominant part in generating oriented crystal morphologies compared to other parameters, such as anisotropy strength, crystallization temperature, and physical noise.

  12. Endothelial surface glycocalyx can regulate flow-induced nitric oxide production in microvessels in vivo.

    Directory of Open Access Journals (Sweden)

    Wanyi Yen

    Full Text Available Due to its unique location, the endothelial surface glycocalyx (ESG at the luminal side of the microvessel wall may serve as a mechano-sensor and transducer of blood flow and thus regulate endothelial functions. To examine this role of the ESG, we used fluorescence microscopy to measure nitric oxide (NO production in post-capillary venules and arterioles of rat mesentery under reduced (low and normal (high flow conditions, with and without enzyme pretreatment to remove heparan sulfate (HS of the ESG and in the presence of an endothelial nitric oxide synthase (eNOS inhibitor, NG-monomethyl-L-arginine (L-NMMA. Rats (SD, 250-300 g were anesthetized. The mesentery was gently taken out from the abdominal cavity and arranged on the surface of a glass coverslip for the measurement. An individual post-capillary venule or arteriole was cannulated and loaded for 45 min with 5 μM 4, 5-Diaminofluorescein diacetate, a membrane permeable fluorescent indictor for NO, then the NO production was measured for ~10 min under a low flow (~300 μm/s and for ~60 min under a high flow (~1000 μm/s. In the 15 min after switching to the high flow, DAF-2-NO fluorescence intensity increased to 1.27-fold of its baseline, DAF-2-NO continuously increased under the high flow, to 1.53-fold of its baseline in 60 min. Inhibition of eNOS by 1 mM L-NMMA attenuated the flow-induced NO production to 1.13-fold in 15 min and 1.30-fold of its baseline in 60 min, respectively. In contrast, no significant increase in NO production was observed after switching to the high flow for 60 min when 1 h pretreatment with 50 mU/mL heparanase III to degrade the ESG was applied. Similar NO production was observed in arterioles under low and high flows and under eNOS inhibition. Our results suggest that ESG participates in endothelial cell mechanosensing and transduction through its heparan sulfate to activate eNOS.

  13. Bone marrow aspiration

    Science.gov (United States)

    Iliac crest tap; Sternal tap; Leukemia - bone marrow aspiration; Aplastic anemia - bone marrow aspiration; Myelodysplastic syndrome - bone marrow aspiration; Thrombocytopenia - bone marrow aspiration; Myelofibrosis - bone marrow aspiration

  14. A Study on the Uncertainty of Flow-Induced Vibration in a Cross Flow over Staggered Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-Su; Park, Jong-Woon [Dongguk univ, Gyeong Ju (Korea, Republic of); Choi, Hyeon-Kyeong [HanNam University, Daejeon (Korea, Republic of)

    2015-05-15

    Cross-flow in many support columns of very high temperature reactor (VHTR) lower plenum would have FIV issues under high speed flow jetting from the core. For a group of multiple circular cylinders subjected to a cross-flow, three types of potential vibration mechanisms may exist: (1) Vortex-induced vibration (VIV), (2) Fluid-elastic vibration (FEV) and (3) Turbulence-induced vibration (TIV). Kevalahan studied the free vibration of circular cylinders in a tightly packed periodic square inline array of cylinders. Pandey et al. studied the flue gas flow distribution in the Low Temperature Super Heater (LTSH) tube bundles situated in second pass of a utility boiler and the phenomenon of flow induced vibration. Nakamura et al. studied flow instability of cylinder arrays resembling U-bend tubes in steam generators. The FIV evaluation is usually performed with computational fluid dynamic (CFD) analysis to obtain unknown frequency of oscillation of the multiple objects under turbulent flow and thus the uncertainty residing in the turbulence model used should be quantified. In this paper, potential FIV uncertainty arising from the turbulence phenomena are evaluated for a typical cross flow through staggered tube bundles resembling the VHTR lower plenum support columns. Flow induced vibration (FIV) is one of the important mechanical and fatigue issues in nuclear systems. Especially, cross-flow in many support structures of VHTR lower plenum would have FIV issues under highly turbulent jet flows from the core. The results show that the effect of turbulence parameters on FIV is not negligible and the uncertainty is 5 to 10%. Present method can be applied to future FIV evaluations of nuclear systems. More extensive studies on flow induced vibration in a plant scale by using more rigorous computational methods are under way.

  15. Impact of mechanical stretch on the cell behaviors of bone and surrounding tissues

    Directory of Open Access Journals (Sweden)

    Hye-Sun Yu

    2016-02-01

    Full Text Available Mechanical loading is recognized to play an important role in regulating the behaviors of cells in bone and surrounding tissues in vivo. Many in vitro studies have been conducted to determine the effects of mechanical loading on individual cell types of the tissues. In this review, we focus specifically on the use of the Flexercell system as a tool for studying cellular responses to mechanical stretch. We assess the literature describing the impact of mechanical stretch on different cell types from bone, muscle, tendon, ligament, and cartilage, describing individual cell phenotype responses. In addition, we review evidence regarding the mechanotransduction pathways that are activated to potentiate these phenotype responses in different cell populations.

  16. Water in hydroxyapatite nanopores: Possible implications for interstitial bone fluid flow.

    Science.gov (United States)

    Lemaire, T; Pham, T T; Capiez-Lernout, E; de Leeuw, N H; Naili, S

    2015-09-18

    The role of bone water in the activity of this organ is essential in structuring apatite crystals, providing pathways for nutrients and waste involved in the metabolism of bone cells and participating in bone remodelling mechanotransduction. It is commonly accepted that bone presents three levels of porosity, namely the vasculature, the lacuno-canalicular system and the voids of the collagen-apatite matrix. Due to the observation of bound state of water at the latter level, the interstitial nanoscopic flow that may exist within these pores is classically neglected. The aim of this paper is to investigate the possibility to obtain a fluid flow at the nanoscale. That is why a molecular dynamics based analysis of a water-hydroxyapatite system is proposed to analyze the effect of water confinement on transport properties. The main result here is that free water can be observed inside hydroxyapatite pores of a few nanometers. This result would have strong implications in the multiscale treatment of the poromechanical behaviour of bone tissue. In particular, the mechanical properties of the bone matrix may be highly controlled by nanoscopic water diffusion and the classical idea that osteocytic activity is only regulated by bone fluid flow within the lacuno-canalicular system may be discussed again. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study

    International Nuclear Information System (INIS)

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-01-01

    Highlights: • An in-situ and real-time electrochemical monitoring of flow-induced corrosion of Mg alloy is designed in a vascular bioreactor. • Effect of hydrodynamics on corrosion kinetics, types, rates and products is analyzed. • Flow accelerates mass and electron transfer, leading to an increase in uniform and localized corrosions. • Flow increases not only the thickness of uniform corrosion product layer, but the removal rate of localized corrosion products. • Electrochemical impedance spectroscopy and linear polarization-measured polarization resistances provide a consistent correlation to corrosion rate calculated by computed tomography. - Abstract: An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography.

  18. Design specifications to ensure flow-induced vibration and fretting-wear performance in CANDU steam generators and heat exchangers

    International Nuclear Information System (INIS)

    Janzen, V.P.; Han, Y.; Pettigrew, M.J.

    2009-01-01

    Preventing flow-induced vibration and fretting-wear problems in steam generators and heat exchangers requires design specifications that bring together specific guidelines, analysis methods, requirements and appropriate performance criteria. This paper outlines the steps required to generate and support such design specifications for CANDU nuclear steam generators and heat exchangers, and relates them to typical steam-generator design features and computer modeling capabilities. It also describes current issues that are driving changes to flow-induced vibration and fretting-wear specifications that can be applied to the design process for component refurbishment, replacement or new designs. These issues include recent experimental or field evidence for new excitation mechanisms, e.g., the possibility of in-plane fluidelastic instability of U-tubes, the demand for longer reactor and component lifetimes, the need for better predictions of dynamic properties and vibration response, e.g., two-phase random-turbulence excitation, and requirements to consider system 'excursions' or abnormal scenarios, e.g., a main steam line break in the case of steam generators. The paper describes steps being taken to resolve these issues. (author)

  19. Effects of Neuropeptides and Mechanical Loading on Bone Cell Resorption in Vitro

    Directory of Open Access Journals (Sweden)

    Yeong-Min Yoo

    2014-04-01

    Full Text Available Neuropeptides such as vasoactive intestinal peptide (VIP and calcitonin gene-related peptide (CGRP are present in nerve fibers of bone tissues and have been suggested to potentially regulate bone remodeling. Oscillatory fluid flow (OFF-induced shear stress is a potent signal in mechanotransduction that is capable of regulating both anabolic and catabolic bone remodeling. However, the interaction between neuropeptides and mechanical induction in bone remodeling is poorly understood. In this study, we attempted to quantify the effects of combined neuropeptides and mechanical stimuli on mRNA and protein expression related to bone resorption. Neuropeptides (VIP or CGRP and/or OFF-induced shear stress were applied to MC3T3-E1 pre-osteoblastic cells and changes in receptor activator of nuclear factor kappa B (NF-κB ligand (RANKL and osteoprotegerin (OPG mRNA and protein levels were quantified. Neuropeptides and OFF-induced shear stress similarly decreased RANKL and increased OPG levels compared to control. Changes were not further enhanced with combined neuropeptides and OFF-induced shear stress. These results suggest that neuropeptides CGRP and VIP have an important role in suppressing bone resorptive activities through RANKL/OPG pathway, similar to mechanical loading.

  20. Angiogenesis is required for successful bone induction during distraction osteogenesis.

    Science.gov (United States)

    Fang, Tony D; Salim, Ali; Xia, Wei; Nacamuli, Randall P; Guccione, Samira; Song, HanJoon M; Carano, Richard A; Filvaroff, Ellen H; Bednarski, Mark D; Giaccia, Amato J; Longaker, Michael T

    2005-07-01

    The role of angiogenesis during mechanically induced bone formation is incompletely understood. The relationship between the mechanical environment, angiogenesis, and bone formation was determined in a rat distraction osteogenesis model. Disruption of either the mechanical environment or endothelial cell proliferation blocked angiogenesis and bone formation. This study further defines the role of the mechanical environment and angiogenesis during distraction osteogenesis. Whereas successful fracture repair requires a coordinated and complex transcriptional program that integrates mechanotransductive signaling, angiogenesis, and osteogenesis, the interdependence of these processes is not fully understood. In this study, we use a system of bony regeneration known as mandibular distraction osteogenesis (DO) in which a controlled mechanical stimulus promotes bone induction after an osteotomy and gradual separation of the osteotomy edges to examine the relationship between the mechanical environment, angiogenesis, and osteogenesis. Adult Sprague-Dawley rats were treated with gradual distraction, gradual distraction plus the angiogenic inhibitor TNP-470, or acute distraction (a model of failed bony regeneration). Animals were killed at the end of distraction (day 13) or at the end of consolidation (day 41) and examined with muCT, histology, and immunohistochemistry for angiogenesis and bone formation (n = 4 per time-point per group). An additional group of animals (n = 6 per time-point per group) was processed for microarray analysis at days 5, 9, 13, 21, and 41. Either TNP-470 administration or disruption of the mechanical environment prevented normal osteogenesis and resulted in a fibrous nonunion. Subsequent analysis of the regenerate showed an absence of angiogenesis by gross histology and immunohistochemical localization of platelet endothelial cell adhesion molecule in the groups that failed to heal. Microarray analysis revealed distinct patterns of expression of

  1. Flow-induced vibration and flow characteristics prediction for a sliding roller gate by two-dimensional unsteady CFD simulation

    International Nuclear Information System (INIS)

    Kim, Nak-Geun; Lee, Kye-Bock; Cho, Yong

    2017-01-01

    Numerical analysis on the flow induced vibration and flow characteristics in the water gate has been carried out by 2-dimensional unsteady CFD simulation when sea water flows into the port in the river. Effect of gate opening on the frequency and the mean velocity and the vortex shedding under the water gate were studied. The streamlines were compared for various gate openings. To get the frequency spectrum, Fourier transform should be performed. Spectral analysis of the excitation force signals permitted identification of the main characteristics of the interaction process. The results show that the sources of disturbed frequency are the vortex shedding from under the water gate. As the gate opening ratio increases, the predicted vibration frequency decreases. The bottom scouring occurs for large gate opening rather than smaller one. The unstable operation conditions can be estimated by using the CFD results and the Strouhal number results for various gate opening gaps.

  2. Flow-Induced Dispersion Analysis for Probing Anti-dsDNA Antibody Binding Heterogeneity in Systemic Lupus Erythematosus Patients

    DEFF Research Database (Denmark)

    Poulsen, Nicklas N; Pedersen, Morten E; Østergaard, Jesper

    2016-01-01

    , specificity, and accuracy with established assays. Also, existing methodologies for quantification of autoantibodies are challenging to transfer to a point-of-care setting. Here we present the use of flow-induced dispersion analysis (FIDA) for rapid (minutes) measurement of autoantibodies against ds......DNA. The assay is based on Taylor dispersion analysis (TDA) and is fully automated with the use of standard capillary electrophoresis (CE) based equipment employing fluorescence detection. It is robust toward matrix effects as demonstrated by the direct analysis of samples composed of up to 85% plasma derived...... from human blood samples, and it allows for flexible exchange of the DNA sequences used to probe for the autoantibodies. Plasma samples from SLE positive patients were analyzed using the new FIDA methodology as well as by standard indirect immunofluorescence and solid-phase immunoassays. Interestingly...

  3. Flow-induced vibration and flow characteristics prediction for a sliding roller gate by two-dimensional unsteady CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nak-Geun; Lee, Kye-Bock [Chungbuk National University, Cheongju (Korea, Republic of); Cho, Yong [Korea Water Resources Corporation, Daejeon (Korea, Republic of)

    2017-07-15

    Numerical analysis on the flow induced vibration and flow characteristics in the water gate has been carried out by 2-dimensional unsteady CFD simulation when sea water flows into the port in the river. Effect of gate opening on the frequency and the mean velocity and the vortex shedding under the water gate were studied. The streamlines were compared for various gate openings. To get the frequency spectrum, Fourier transform should be performed. Spectral analysis of the excitation force signals permitted identification of the main characteristics of the interaction process. The results show that the sources of disturbed frequency are the vortex shedding from under the water gate. As the gate opening ratio increases, the predicted vibration frequency decreases. The bottom scouring occurs for large gate opening rather than smaller one. The unstable operation conditions can be estimated by using the CFD results and the Strouhal number results for various gate opening gaps.

  4. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study

    Science.gov (United States)

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-01-01

    An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography. PMID:28626241

  5. Flow-Induced Pulsation and Vibration in Hydroelectric Machinery Engineer’s Guidebook for Planning, Design and Troubleshooting

    CERN Document Server

    Dörfler, Peter; Coutu, André

    2013-01-01

    Since the 1970’s, an increasing amount of specialized research has focused on the problems created by instability of internal flow in hydroelectric power plants. However, progress in this field is hampered by the inter­disciplinary nature of the subject, between fluid mechanics, structural mechanics and hydraulic transients. Flow-induced Pulsation and Vibration in Hydroelectric Machinery provides a compact guidebook explaining the many different underlying physical mechanisms and their possible effects.   Typical phenomena are described to assist in the proper diagnosis of problems and various key strategies for solution are compared and considered with support from practical experience and real-life examples. The link between state-of the-art CFD computation and notorious practical problems is discussed  and quantitative data is provided on  normal levels of vibration and pulsation so realistic limits can be set for future projects. Current projects are also addressed as the possibilities and limitatio...

  6. IAEA specialist meeting on flow induced vibrations in fast breeder reactors, Paris, France, 22-24 October 1986

    International Nuclear Information System (INIS)

    Perez, M.A.

    1986-10-01

    The Specialists' Meeting on ''Flow Induced Vibrations in FBRs for LMFBR Applications'' was held in Paris under the auspices of the French CEA on 21-24 October 1982. The meeting was sponsored by the IAEA on the recommendation of the 14th Meeting of the IWGFR and was attended by 31 participants from France, the Federal Republic of Germany, India, Italy, Japan, the United Kingdom, the Union of Soviet Socialist Republics, the United States of America and one international organization (IAEA). The meeting was presided over by Pr. R.J. Gibert of France. After the first session on review of national positions in the subject field (7 papers), the meeting was divided into five technical sections as follows: fluid-structures interaction, calculation methods (3 papers); tubes bundles vibration and weir (4 papers); instability (6 papers); induced vibrations in the pumps (2 papers). A separate abstract was prepared for each of these papers

  7. PIV measurements of acoustic flow-induced vibration in a rectangular channel with co-axial side branches

    International Nuclear Information System (INIS)

    Li, Yanrong; Someya, Satoshi; Okamoto, Koji

    2010-01-01

    Systems with closed side-branches are liable to an excitation of sound, as called cavity tone. In this study, flow-induced acoustic resonances of piping systems containing closed side-branches were investigated experimentally. The present investigation on the coaxial closed side-branches is the first rudimentary study to measure the pressure at the downstream side opening of the cavity by microphone and to visualize the fluid flow in the cross-section by using PIV. High-time-resolved PIV has a possibility to analyze the velocity field and the relation between sound propagation and flow field. The fluid flows at different points in the cavity interact with some phase differences and the relation can be clarified. (author)

  8. Probing the mystery of Chinese medicine meridian channels with special emphasis on the connective tissue interstitial fluid system, mechanotransduction, cells durotaxis and mast cell degranulation

    Directory of Open Access Journals (Sweden)

    Fung Peter

    2009-05-01

    Full Text Available Abstract This article hypothesizes that the Chinese medicine meridian system is a special channel network comprising of skin with abundant nerves and nociceptive receptors of various types, and deeper connective tissues inside the body with the flowing interstitial fluid system. These meridian channels provide efficient migratory tracks mainly due to durotaxis (also including chemotaxis for mast cells, fibroblasts and other cells to migrate and carry out a number of physiological functions. Acupuncture acting on meridian channel causes cytoskeletal remodeling through mechanotransduction, leading to regulation of gene expression and the subsequent production of related proteins. Also, stimulation on cell surface can trigger Ca2+ activities, resulting in a cascade of intra- and inter-cellular signaling. Moreover, nerve endings in the meridian channels interact with mast cells and induce the degranulation of these cells, leading to the release of many specific biomolecules needed for homeostasis, immune surveillance, wound healing and tissue repair. Acupoint along a meridian channel is a functional site to trigger the above functions with specificity and high efficiency.

  9. Vascular mechanotransduction data in a rodent model of diabetes: Pressure-induced regulation of SHP2 and associated signaling in the rat inferior vena cava

    Directory of Open Access Journals (Sweden)

    Kevin M. Rice

    2017-12-01

    Full Text Available The effect of diabetes on vascular mechano-transductive response is of great concern. Given the higher rate of vein graft failures associated with diabetes, understanding the multiple cellular and molecular events associated with vascular remodeling is of vital importance. This article represents data related to a study published in Cardiovascular Diabetology [1] (Rice et al., 2006 and Open Journal of Endocrine and Metabolic Diseases [2] (Rice et al., 2015 evaluating the effect of pressurization on rat inferior venae cavae (IVC. Provided within this articles is information related to the method and processing of raw data related to our prior publish work and Data in Brief articles [3,4] (Rice et al., 2017, as well as the evaluation of alternation in SHP-2 signaling and associated proteins in response to mechanical force. IVC from lean and obese animals were exposed to a 30 min perfusion of 120 mm Hg pressure and evaluated for changes in expression of SHP2, BCL-3, BCL-XL, HSP 27, HSP 70, and PI3K p85, along with the phosphorylation of SHP-2 (Tyr 542.

  10. Broken bone

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Broken bone URL of this page: //medlineplus.gov/ency/ ... following steps to reduce your risk of a broken bone: Wear protective ... pads. Create a safe home for young children. Place a gate at stairways ...

  11. Surface Waves and Flow-Induced Oscillations along an Underground Elliptic Cylinder Filled with a Viscous Fluid

    Science.gov (United States)

    Sakuraba, A.

    2015-12-01

    I made a linear analysis of flow-induced oscillations along an underground cylindrical conduit with an elliptical cross section on the basis of the hypothesis that volcanic tremor is a result of magma movement through a conduit. As a first step to understand how the self oscillation occurs because of magma flow, I investigated surface wave propagation and attenuation along an infinitely long fluid-filled elliptic cylinder in an elastic medium. The boundary element method is used to obtain the two-dimensional wave field around the ellipse in the frequency-wavenumber domain. When the major axis is much greater than the minor axis of the ellipse, we obtain the analytic form of the dispersion relation of both the crack-wave mode (Korneev 2008, Lipovsky & Dunham 2015) and the Rayleigh-wave mode with flexural deformation. The crack-wave mode generally has a slower phase speed and a higher attenuation than the Rayleigh-wave mode. In the long-wavelength limit, the crack-wave mode disappears because of fluid viscosity, but the Rayleigh-wave mode exists with a constant Q-value that depends on viscosity. When the aspect ratio of the ellipse is finite, the surface waves can basically be understood as those propagating along a fluid pipe. The flexural mode does exist even when the wavelength is much longer than the major axis, but its phase speed coincides with that of the surrounding S-wave (Randall 1991). As its attenuation is zero in the long-wavelength limit, the flexural mode differs in nature from surface wave. I also obtain a result on linear stability of viscous flow through an elliptic cylinder. In this analysis, I made an assumption that the fluid inertia is so small that the Stokes equation can be used. As suggested by the author's previous study (Sakuraba & Yamauchi 2014), the flexural (Rayleigh-wave) mode is destabilized at a critical flow speed that decreases with the wavelength. However, when the wavelength is much greater than the major axis of the ellipse, the

  12. Bone Scan

    Science.gov (United States)

    ... posts Join Mayo Clinic Connect Bone scan About Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  13. Bone Biopsy

    Science.gov (United States)

    ... bear denotes child-specific content. Related Articles and Media Computed Tomography (CT) - Body Magnetic Resonance Imaging (MRI) - Body X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Bone Biopsy Sponsored by Please note ...

  14. Bone sarcomas

    International Nuclear Information System (INIS)

    Mudry, P.

    2008-01-01

    Bone sarcomas are malignancies with peak incidence in adolescents and young adults. The most frequent are osteosarcoma and Ewing sarcoma/PNET, in an older adults are seen chondrosarcomas, other ones are rare. In general, biology of sarcomas is closely related to pediatric malignancies with fast growth, local aggressiveness, tendency to early hematogenic dissemination and chemo sensitivity. Diagnostics and treatment of bone sarcomas should be done in well experienced centres due to low incidence and broad issue of this topic. An interdisciplinary approach and staff education is essential in due care of patients with bone sarcoma. If these criteria are achieved, the cure rate is contemporary at 65 - 70 %, while some subpopulation of patients has chance for cure up to 90 %. Osteosarcoma and Ewing sarcoma/PNET are discussed below as types of most frequent bone sarcoma. (author)

  15. Bone pain

    DEFF Research Database (Denmark)

    Frost, Charlotte Ørsted; Hansen, Rikke Rie; Heegaard, Anne-Marie

    2016-01-01

    Skeletal conditions are common causes of chronic pain and there is an unmet medical need for improved treatment options. Bone pain is currently managed with disease modifying agents and/or analgesics depending on the condition. Disease modifying agents affect the underlying pathophysiology...... of the disease and reduce as a secondary effect bone pain. Antiresorptive and anabolic agents, such as bisphosphonates and intermittent parathyroid hormone (1-34), respectively, have proven effective as pain relieving agents. Cathepsin K inhibitors and anti-sclerostin antibodies hold, due to their disease...... modifying effects, promise of a pain relieving effect. NSAIDs and opioids are widely employed in the treatment of bone pain. However, recent preclinical findings demonstrating a unique neuronal innervation of bone tissue and sprouting of sensory nerve fibers open for new treatment possibilities....

  16. Human osteoblast-like cells respond to mechanical strain with increased bone matrix protein production independent of hormonal regulation

    Science.gov (United States)

    Harter, L. V.; Hruska, K. A.; Duncan, R. L.

    1995-01-01

    Exposure of osteosarcoma cell lines to chronic intermittent strain increases the activity of mechano-sensitive cation (SA-cat) channels. The impact of mechano-transduction on osteoblast function has not been well studied. We analyzed the expression and production of bone matrix proteins in human osteoblast-like osteosarcoma cells, OHS-4, in response to chronic intermittent mechanical strain. The OHS-4 cells exhibit type I collagen production, 1,25-Dihydroxyvitamin D-inducible osteocalcin, and mineralization of the extracellular matrix. The matrix protein message level was determined from total RNA isolated from cells exposed to 1-4 days of chronic intermittent strain. Northern analysis for type I collagen indicated that strain increased collagen message after 48 h. Immunofluorescent labeling of type I collagen demonstrated that secretion was also enhanced with mechanical strain. Osteopontin message levels were increased several-fold by the application of mechanical load in the absence of vitamin D, and the two stimuli together produced an additive effect. Osteocalcin secretion was also increased with cyclic strain. Osteocalcin levels were not detectable in vitamin D-untreated control cells. However, after 4 days of induced load, significant levels of osteocalcin were observed in the medium. With vitamin D present, osteocalcin levels were 4 times higher in the medium of strained cells compared to nonstrained controls. We conclude that mechanical strain of osteoblast-like cells is sufficient to increase the transcription and secretion of matrix proteins via mechano-transduction without hormonal induction.

  17. Numerical Research about Influence of Blade Outlet Angle on Flow-Induced Noise and Vibration for Centrifugal Pump

    Directory of Open Access Journals (Sweden)

    Ailing Yang

    2014-03-01

    Full Text Available A hybrid numerical method was used to calculate the flow-induced noise and vibration of the centrifugal pump in the paper. The unsteady flows inside the centrifugal pumps with different blade outlet angles were simulated firstly. The unsteady pressure on the inner surface of the volute and the unsteady force applied on the impeller were analyzed. Then the vibration of the volute and sound field were calculated based on an acoustic-vibro-coupling method. The results show that the pump head has increased 7% while the hydraulic efficiency decreased 11.75% as blade outlet angles increased from 18° to 39°. The amplitude of pressure fluctuation at the first blade passing frequency has decreased but increased at the second-order blade passing frequency as the angle growing. The total fluctuation power near volute tongue goes up about 12% every 3° increment of blade outlet angle. The results also show that vibrating-velocity of the volute at second-order blade passing frequency is much higher than at other frequencies, and the velocity increases rapidly as blade outlet angle varies from 18° to 39°. At the same time, the sound pressure level outside the pump has increased about 8.6 dB when the angle increased from 18° to 39°.

  18. Linear Aspects of Stability in Flow Induced Oscillations of Cantilever Pipes: Application of a Popular Heuristic Algorithm

    Science.gov (United States)

    Hebbar, Ullhas; Krishnan, Abilash; Kadoli, Ravikiran

    2017-11-01

    This work studied linear aspects of flow induced oscillations in cantilever pipes, with an emphasis on the numerical method of solution adopted for the system of governing equations. The complex frequencies of vibration of the different characteristic modes of the system were computed as a function of the flow velocity, wherein multi-variable minimization was performed using the popular Nelder-Mead heuristic algorithm. Results for a canonical fluid-to-pipe mass ratio (β) were validated with literature, and the evolution of frequencies was studied for different mass ratios. Additionally, the numerical scheme was implemented to compute critical conditions of stability for the cantilever system as a function of β. Finally, interesting aspects of the dynamics of the system were analyzed: the supposed `mode exchange' behavior, and an explanation for discontinuities observed in the critical conditions plotted as a function of β. In conclusion, the heuristic optimization based solution used in this study can be used to analyze various aspects of linear stability in pipes conveying fluid. Part of the submitted work was completed at the author's previous affiliation - National Institute of Technology Karnataka, India.

  19. Changes in distribution of hepatic blood flow induced by intra-arterial infusion of angiotensin II in human hepatic cancer

    International Nuclear Information System (INIS)

    Sasaki, Y.; Imaoka, S.; Hasegawa, Y.

    1985-01-01

    Changes in the distribution of the hepatic blood flow induced by intra-arterial infusion of angiotensin II (AT-II) were studied in human hepatic cancers using extremely short-lived radioisotope (RI) (krypton 81 m [/sup 81m/Kr]; half-life, 13 seconds). After the start of continuous infusion of AT-II, the radioactivity of the tumor showed about a two-fold increase, whereas that of the nontumor region decreased to about one half as much as the level before the infusion. Consequently, the mean ratio of the arterial blood flow in the tumor region to that in the nontumor region (T/N ratio) increased to 3.30 (P less than 0.001). The T/N ratio showed a peak before the peripheral blood pressure reached the maximum, and thereafter tended to decrease. Intra-arterial infusion of AT-II raised the T/N ratio more obviously than did intravenous infusion of the drug, with less rise in the peripheral blood pressure. It is believed that intra-arterial infusion chemotherapy with local use of AT-II enables better accessibility of chemotherapeutic drugs to tumors

  20. Experimental Analysis of Flow-Induced Matrix Deformation on Deviation from Darcy's Law in Deformable Porous Media

    Science.gov (United States)

    Munro, Benjamin; Becker, Sid

    2017-11-01

    When a viscous fluid flows through a deformable porous medium, the response of the matrix and the flow field is coupled. The flow of the fluid through the elastic media causes matrix deformation and conversely, deformation of the matrix affects the fluid field by altering pressure within the pores. This study concerns the effect of flow-induced matrix deformation on deviation from Darcy's law at low Reynolds numbers in a deformable porous medium. The experiments consist of a glycerol and water mixture driven through an isotropic elastic porous matrix by an externally applied pressure gradient. The method of elastic matrix manufacture allows for a particular control of the matrix parameters: elasticity and pore geometry. The coupled solid-fluid interaction is then observed in an experimental test rig which captures the global flow behaviour, matrix deformation, and the onset of deviation from Darcy's law at low Re. The experimental data is then compared against theoretical and computational models, and presented so that the results can be used for numerical validation.

  1. Hemodynamic, biological, and right ventricular functional changes following intraatrial shunt repair in patients with flow-induced pulmonary hypertension.

    Science.gov (United States)

    Hsu, Chih-Hsin; Roan, Jun-Neng; Wang, Jieh-Neng; Huang, Chien-Chi; Shih, Chao-Jung; Chen, Jyh-Hong; Wu, Jing-Ming; Lam, Chen-Fuh

    2017-07-01

    Atrial septal defects may result in pulmonary hypertension and right heart remodeling. We analyzed improvements in patients with flow-induced pulmonary hypertension and the activation of endothelial progenitor cells after flow reduction. This prospective cohort study included 37 patients who were admitted for an occluder implantation. Blood samples were collected before and after the procedure. We determined the number of endothelial progenitor cells in outgrowth colonies and serum Hsp27 concentrations. Daily performance and cardiothoracic ratio were reevaluated later. Closure of the defect significantly reduced the pulmonary pressure and B-type natriuretic peptide levels. The cardiothoracic ratio and daily performance status also improved. The number of endothelial progenitor cell outgrowth colony-forming units significantly increased and was positively correlated with daily performance. In patients with enhanced colony formation, Hsp27 levels were significantly increased. The implantation of an occluder successfully improved hemodynamic, right ventricular, and daily performance. Qualitative enhancement of colony formation for endothelial progenitor cells was also noted and positively correlated with daily performance. Closure of defects may serve as a valid, reliable model to obtain a deeper understanding of the modulation of endothelial progenitor cell activity and its relationship with pulmonary hypertension prognosis. © 2017 Wiley Periodicals, Inc.

  2. Computational modelling of blood-flow-induced changes in blood electrical conductivity and its contribution to the impedance cardiogram.

    Science.gov (United States)

    Trakic, A; Akhand, M; Wang, H; Mason, D; Liu, F; Wilson, S; Crozier, S

    2010-01-01

    Studies have shown that blood-flow-induced change in electrical conductivity is of equal importance in assessment of the impedance cardiogram (ICG) as are volumetric changes attributed to the motion of heart, lungs and blood vessels. To better understand the sole effect of time-varying blood conductivity on the spatiotemporal distribution of trans-thoracic electric fields (i.e. ICG), this paper presents a segmented high-resolution (1 mm(3)) thoracic cardiovascular system, in which the time-varying pressures, flows and electrical conductivities of blood in different vessels are evaluated using a set of coupled nonlinear differential equations, red blood cell orientation and cardiac cycle functions. Electric field and voltage simulations are performed using two and four electrode configurations delivering a small alternating electric current to an anatomically realistic and electrically accurate model of modelled human torso. The simulations provide a three-dimensional electric field distribution and show that the time-varying blood conductivity alters the voltage potential difference between the electrodes by a maximum of 0.28% for a cardiac output of about 5 L min(-1). As part of a larger study, it is hoped that this initial model will be useful in providing improved insights into blood-flow-related spatiotemporal electric field variations and assist in the optimal placement of electrodes in impedance cardiography experiments.

  3. Study on flow-induced acoustic resonance in symmetrically located side-branches using dynamic PIV technique

    International Nuclear Information System (INIS)

    Li, Yanrong; Inagaki, Terumi; Nishi, Yasuyuki; Someya, Satoshi; Okamoto, Koji

    2014-01-01

    Flow-induced acoustic resonance in a piping system containing closed coaxial side-branches was investigated experimentally. Resonance characteristics of the piping system were examined by a microphone. The results revealed that the resonance frequencies of the shear layer instability were locked in corresponding to the natural frequencies of the side-branches. Phase-averaged velocity fields were obtained two-dimensionally in the junction of coaxial side-branches by dynamic particle image velocimetry (PIV), while the acoustic resonance was induced at the first and second hydrodynamic modes. Patterns of jet correspond to two hydrodynamic modes were derived from the phase-averaged velocity fields. The dynamic PIV can acquire time-series velocity fluctuations, then, two-dimensional phase delay maps under resonance and off-resonance conditions in the junction of coaxial side-branches were obtained. Experimental results show that the proposed phase delay map method costs less experiment and computation time and achieves a better accuracy and repetition than the phase-locking technique. In addition, the phase delay map method can obtain phase difference under the different frequency components. This is important when two different acoustic modes were induced in one experimental condition. (author)

  4. Medicines and Bone Loss

    Science.gov (United States)

    Fact Sheet Medici a ne n s d Bone Loss Some types of medicines can cause bone loss, making your bones weak, if used for a long time. Use over a short time ... old bone and replaces it with new bone. Bone loss occurs when old bone breaks down faster than ...

  5. FLow-induced PRotrusions (FLIPRs): a platelet-derived platform for the retrieval of microparticles by monocytes and neutrophils.

    Science.gov (United States)

    Tersteeg, Claudia; Heijnen, Harry F; Eckly, Anita; Pasterkamp, Gerard; Urbanus, Rolf T; Maas, Coen; Hoefer, Imo E; Nieuwland, Rienk; Farndale, Richard W; Gachet, Christian; de Groot, Philip G; Roest, Mark

    2014-02-28

    Platelets are the most important cells in the primary prevention of blood loss after injury. In addition, platelets are at the interface between circulating leukocytes and the (sub)endothelium regulating inflammatory responses. Our aim was to study the dynamic process that leads to the formation of procoagulant and proinflammatory platelets under physiological flow. In the present study, we describe the formation of extremely long, negatively charged membrane strands that emerge from platelets adhered under flow. These flow-induced protrusions (FLIPRs) are formed in vitro on different physiological substrates and are also detected in vivo in a mouse carotid injury model. FLIPRs are formed downstream the adherent and activated platelets and reach lengths of 250 μm. FLIPR formation is shear-dependent and requires cyclophilin D, calpain, and Rac1 activation. It is accompanied by a disassembly of the F-actin and microtubule organization. Monocytes and neutrophils roll over FLIPRs in a P-selectin/P-selectin glycoprotein ligand-1-dependent manner, retrieving fragments of FLIPRs as microparticles on their surface. Consequently, monocytes and neutrophils become activated, as demonstrated by increased CD11b expression and L-selectin shedding. The formation of long platelet membrane extensions, such as the ones presented in our flow model, may pave the way to generate an increased membrane surface for interaction with monocytes and neutrophils. Our study provides a mechanistic model for platelet membrane transfer and the generation of monocyte/neutrophil-microparticle complexes. We propose that the formation of FLIPRs in vivo contributes to the well-established proinflammatory function of platelets and platelet-derived microparticles.

  6. Flow-induced vibration and fretting-wear specifications to ensure steam-generator and heat exchanger lifetime performance

    International Nuclear Information System (INIS)

    Janzen, V.P.; Han, Y.; Pettigrew, M.J.

    2008-01-01

    The current interest in refurbishment, life extension and new-build activity has meant a renewed emphasis on technical specifications that will ensure improved reliability and longer life. Preventing vibration and fretting-wear problems in steam generators and heat exchangers requires design specifications that bring together specific guidelines, analysis methods, requirements and appropriate performance criteria. The specifications must be firmly based on experimental data and field inspections. In addition, the specifications must be supported by theoretical analyses and fundamental scaling correlations, to cover conditions and geometries over the wide range applicable to existing components and probable future designs. The specifications are expected to evolve to meet changing industry requirements. This paper outlines the steps required to generate and support design specifications, and relates them to typical steam-generator design features and computer modeling capabilities. It also describes current issues that are driving changes to flow-induced vibration and fretting-wear specifications that can be applied to the design process for component refurbishment, replacement or new designs. These issues include recent experimental or field evidence for new excitation mechanisms, e.g., the possibility of in-plane fluidelastic instability of U-tubes, the demand for longer reactor and component lifetimes, the need for better predictions of dynamic properties and vibration response, e.g., two-phase random-turbulence excitation, and requirements to consider system 'excursions' or abnormal scenarios, e.g., a main steam line break in the case of steam generators. The paper describes steps being taken to resolve these issues. (author)

  7. Frequency Dependence of Helioseismic Measurements of the Center-to-Limb Effect and Flow-induced Travel-time Shifts

    Science.gov (United States)

    Chen, Ruizhu; Zhao, Junwei

    2018-02-01

    Time–distance helioseismology measures acoustic travel times to infer the structure and flow field of the solar interior; however, both the mean travel times and the travel-time shifts suffer systematic center-to-limb variations, which complicate the interpretation and inversions of the time–distance measurements. In particular, the center-to-limb variation in travel-time shifts (CtoL effect) has a significant impact on the inference of the Sun’s meridional circulation, and needs to be removed from the helioseismic measurements, although the observational properties and the physical cause of the CtoL effect have yet to be investigated. In this study, we measure the CtoL effect in the frequency domain using Doppler-velocity data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, and study its properties as a function of disk-centric distance, travel distance, and frequency of acoustic waves. It is found that the CtoL effect has a significant frequency dependence—it reverses sign at a frequency around 5.4 mHz and reaches maximum at around 4.0 mHz before the sign reversal. The tendency of frequency dependence varies with disk-centric distance in a way that both the sign-reversal frequency and the maximum-value frequency decrease closer to the limb. The variation tendency does not change with travel distance, but the variation magnitude is approximately proportional to travel distance. For comparison, the flow-induced travel-time shifts show little frequency dependence. These observational properties provide more clues on the nature of the CtoL effect, and also possibly lead to new ways of effect-removal for a more robust determination of the deep meridional flow.

  8. Ganoderma Triterpenoids Exert Antiatherogenic Effects in Mice by Alleviating Disturbed Flow-Induced Oxidative Stress and Inflammation

    Directory of Open Access Journals (Sweden)

    Pei-Ling Hsu

    2018-01-01

    eliminating disturbed flow-induced oxidative stress and inflammation.

  9. Experimental validation of the design method to prevent flow-induced vibration in high Reynolds-number

    International Nuclear Information System (INIS)

    Sakai, Takaaki; Yamaguchi, Akira; Morisita, Masaki; Iwata, Koji

    1998-08-01

    The incident of sodium leakage from a main pipe of the secondary heat transport system of Monju fast breeder reactor was caused by the failure of a thermometer well. 'Flow-induced vibration design guide for thermometer wells' (express as 'design guide') was proposed by PNC Working Group to prevent the same cause of the sodium leak incident in future. On this report, applicability of the 'design guide' was estimated to plant conditions in high Reynolds-number(approximately 3x10 5 ∼ 3x10 6 ) involving the supercritical region, by measured data on a vortex synchronized vibration and a turbulence induced vibration. Experiments were performed for cylindrical and taper shaped types of test pieces. As results, reduced velocity (Vr) at onsets of the inline synchronized vibration were evaluated to be grater than 1.0 in the range of experimental conditions. Fluctuating drag and lift coefficients, which were evaluated from power spectrum of turbulence for Vr < 1.0 condition, were 0.01 ∼ 0.05 for drag direction and 0.04 ∼ 0.13 for lift direction. The fluctuating drag and lift coefficients used in the 'design guide' were estimated to be conservative by comparison with these data. Correlation lengths for a cylinder and a taper shaped one in the high Reynolds-number region were estimated to be 1.6 times of the diameter(D) in the maximum case. The measured value of correlation length is enough smaller than the 'design guide' value of 3.0D. Displacement amplitudes of test pieces for Vr < 1.0 conditions were enough smaller (fives times) than calculated values based on the 'design guide'. Consequently, the applicability of the design guide' was confirmed in the range of experiments involving the super critical Reynolds-number region. (author)

  10. Experimental modeling of flow-induced vibration of multi-span U-tubes in a CANDU steam generator

    International Nuclear Information System (INIS)

    Mohany, A.; Feenstra, P.; Janzen, V.P.; Richard, R.

    2009-01-01

    Flow-induced vibration of the tubes in a nuclear steam generator is a concern for designers who are trying to increase the life span of these units. The dominant excitation mechanisms are fluidelastic instability and random turbulence excitation. The outermost U-bend region of the tubes is of greatest concern because the flow is almost perpendicular to the tube axis and the unsupported span is relatively long. The support system in this region must be well designed in order to minimize fretting wear of the tubes at the support locations. Much of the previous testing was conducted on straight single-span or cantilevered tubes in cross-flow. However, the dynamic response of steam generator multi-span U-tubes with clearance supports is expected to be different. Accurate modeling of the tube dynamics is important to properly simulate the dynamic interaction of the tube and supports. This paper describes a test program that was developed to measure the dynamic response of a bundle of steam generator U-tubes with Anti-Vibration Bar (AVB) supports, subjected to Freon two-phase cross-flow. The tube bundle has similar geometrical conditions to those expected for future CANDU steam generators. Future steam generators will be larger than previous CANDU steam generators, nearly twice the heat transfer area, with significant changes in process conditions in the U-bend region, such as increased steam quality and a broader range of flow velocities. This test program was initiated at AECL to demonstrate that the tube support design for future CANDU steam generators will meet the stringent requirements associated with a 60 year design life. The main objective of the tests is to address the issue of in-plane and out-of-plane fluidelastic instability and random turbulent excitation of a U-tube bundle with Anti-Vibration Bar (AVB) supports. Details of the test rig, measurement techniques and preliminary instrumentation results are described in the paper. (author)

  11. From bone biology to bone analysis.

    NARCIS (Netherlands)

    Schoenau, E.; Saggese, G.; Peter, F.; Baroncelli, G.I.; Shaw, N.J.; Crabtree, N.J.; Zadik, Z.; Neu, C.M.; Noordam, C.; Radetti, G.; Hochberg, Z.

    2004-01-01

    Bone development is one of the key processes characterizing childhood and adolescence. Understanding this process is not only important for physicians treating pediatric bone disorders, but also for clinicians and researchers dealing with postmenopausal and senile osteoporosis. Bone densitometry has

  12. Bone mineral content and bone metabolism in young adults with severe periodontitis

    DEFF Research Database (Denmark)

    Wowern von, N.; Westergaard, J.; Kollerup, G.

    2001-01-01

    Bone loss, bone markers, bone metabolism, bone mineral content, osteoporosis, severe periodontitis......Bone loss, bone markers, bone metabolism, bone mineral content, osteoporosis, severe periodontitis...

  13. Flow-induced vibration analysis of Three Mile Island Unit-2 once-through steam generator tubes. Volume 1. Final report

    International Nuclear Information System (INIS)

    Johnson, J.R.; Brown, J.C.; Harris, C.E.; McGuinn, E.J.; Simonis, J.C.; Thoren, D.E.

    1981-06-01

    Tube responses to flow-induced vibration were measured in the top two spans and the tenth span in the B once-through steam generator at Three Mile Island, Unit 2. This program evaluated the effects of flow-induced biration of OTSG tubes during steady-state and transient operation. Twenty-three tubes were instrumented with accelerometers and strain gages in tubes located along the open lane, in the bundle, and at the tenth span. Tube displacements, frequencies, dynamic strains, and mode shapes were determined during steady-state and transient operation. Pressure sensors were installed in the OTSG to measure pressure fluctuations and plant parameters, which were recorded for correlation with tube response. Data analysis results indicate that the steady-state tube response increases with increasing reactor power, with the maximum response (12 mils peak to peak at midspan) at the outer perimeter of the generator in the 16th span

  14. Facts about Broken Bones

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Broken Bones KidsHealth / For Kids / Broken Bones What's in this ... sticking through the skin . What Happens When a Bone Breaks? It hurts to break a bone! It's ...

  15. Bone lesion biopsy

    Science.gov (United States)

    Bone biopsy; Biopsy - bone ... the cut, then pushed and twisted into the bone. Once the sample is obtained, the needle is ... sample is sent to a lab for examination. Bone biopsy may also be done under general anesthesia ...

  16. Flow-induced endothelial cell alignment requires the RhoGEF Trio as a scaffold protein to polarize active Rac1 distribution.

    Science.gov (United States)

    Kroon, Jeffrey; Heemskerk, Niels; Kalsbeek, Martin J T; de Waard, Vivian; van Rijssel, Jos; van Buul, Jaap D

    2017-07-01

    Endothelial cells line the lumen of the vessel wall and are exposed to flow. In linear parts of the vessel, the endothelial cells experience laminar flow, resulting in endothelial cell alignment in the direction of flow, thereby protecting the vessel wall from inflammation and permeability. In order for endothelial cells to align, they undergo rapid remodeling of the actin cytoskeleton by local activation of the small GTPase Rac1. However, it is not clear whether sustained and local activation of Rac1 is required for long-term flow-induced cell alignment. Using a FRET-based DORA Rac1 biosensor, we show that local Rac1 activity remains for 12 h upon long-term flow. Silencing studies show that the RhoGEF Trio is crucial for keeping active Rac1 at the downstream side of the cell and, as a result, for long-term flow-induced cell alignment. Surprisingly, Trio appears to be not involved in flow-induced activation of Rac1. Our data show that flow induces Rac1 activity at the downstream side of the cell in a Trio-dependent manner and that Trio functions as a scaffold protein rather than a functional GEF under long-term flow conditions. © 2017 Kroon et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  17. Analysis of Mitogen-Activated Protein Kinases in Bone and Cartilage of Patients with Rheumatoid Arthritis Treated with Abatacept

    Directory of Open Access Journals (Sweden)

    Katsuaki Kanbe

    2016-01-01

    Full Text Available The aim of this study was to analyze the histological changes related to mitogen-activated protein (MAP kinases in bone and cartilage treated with abatacept for rheumatoid arthritis (RA. A total of 20 patients of bone and cartilage were assessed: 10 abatacept with methotrexate (MTX-treated RA patients were compared with 10 MTX-treated RA patients (control. The histology of bone and cartilage was observed by staining with hematoxylin and eosin and analyzed immunohistochemically for the expression of tumor necrosis factor-α, interleukin-6, CD4 (T cell, CD68 (macrophage, receptor activator of nuclear kappa-B ligand, osteoprotegerin, osteopontin, CD29 (β-1 integrin, phospho-p38 MAPK (Tyr180/Tyr182, phospho-p44/42 MAPK (extracellular signal-regulated kinase, ERK1/ERK2, and phosphor-c-Jun N-terminal kinase. The expressions of CD29 known as mechanoreceptor and ERK known as mechanotransduction signal protein in MAP kinases in the bone and cartilage of patients treated with abatacept were significantly different from those of control. These findings suggest that increases in CD29 and ERK in MAP kinases may change the metabolism of bone and cartilage in RA patients treated with abatacept.

  18. Osteoclasts prefer aged bone

    DEFF Research Database (Denmark)

    Henriksen, K; Leeming, Diana Julie; Byrjalsen, I

    2007-01-01

    We investigated whether the age of the bones endogenously exerts control over the bone resorption ability of the osteoclasts, and found that osteoclasts preferentially develop and resorb bone on aged bone. These findings indicate that the bone matrix itself plays a role in targeted remodeling...... of aged bones....

  19. Bone marker gene expression in calvarial bones: different bone microenvironments.

    Science.gov (United States)

    Al-Amer, Osama

    2017-12-01

    In calvarial mice, mesenchymal stem cells (MSCs) differentiate into osteoprogenitor cells and then differentiate into osteoblasts that differentiate into osteocytes, which become embedded within the bone matrix. In this case, the cells participating in bone formation include MSCs, osteoprogenitor cells, osteoblasts and osteocytes. The calvariae of C57BL/KaLwRijHsD mice consist of the following five bones: two frontal bones, two parietal bones and one interparietal bone. This study aimed to analyse some bone marker genes and bone related genes to determine whether these calvarial bones have different bone microenvironments. C57BL/KaLwRijHsD calvariae were carefully excised from five male mice that were 4-6 weeks of age. Frontal, parietal, and interparietal bones were dissected to determine the bone microenvironment in calvariae. Haematoxylin and eosin staining was used to determine the morphology of different calvarial bones under microscopy. TaqMan was used to analyse the relative expression of Runx2, OC, OSX, RANK, RANKL, OPG, N-cadherin, E-cadherin, FGF2 and FGFR1 genes in different parts of the calvariae. Histological analysis demonstrated different bone marrow (BM) areas between the different parts of the calvariae. The data show that parietal bones have the smallest BM area compared to frontal and interparietal bones. TaqMan data show a significant increase in the expression level of Runx2, OC, OSX, RANKL, OPG, FGF2 and FGFR1 genes in the parietal bones compared with the frontal and interparietal bones of calvariae. This study provides evidence that different calvarial bones, frontal, parietal and interparietal, contain different bone microenvironments.

  20. [Frontier in bone biology].

    Science.gov (United States)

    Takeda, Shu

    2015-10-01

    Bone is an active organ in which bone mass is maintained by the balance between osteoblastic bone formation and osteoclastic bone resorption, i.e., coupling of bone formation and bone resorption. Recent advances in molecular bone biology uncovered the molecular mechanism of the coupling. A fundamental role of osteocyte in the maintenance of bone mass and whole body metabolism has also been revealed recently. Moreover, neurons and neuropeptides have been shown to be intimately involved in bone homeostasis though inter-organ network, in addition to "traditional" regulators of bone metabolism such as soluble factors and cytokines

  1. Lab-on-a-chip platforms for quantification of multicellular interactions in bone remodeling.

    Science.gov (United States)

    George, Estee L; Truesdell, Sharon L; York, Spencer L; Saunders, Marnie M

    2018-04-01

    Researchers have been using lab-on-a-chip systems to isolate factors for study, simulate laboratory analysis and model cellular, tissue and organ level processes. The technology is increasing rapidly, but the bone field has been slow to keep pace. Novel models are needed that have the power and flexibility to investigate the elegant and synchronous multicellular interactions that occur in normal bone turnover and in disease states in which remodeling is implicated. By removing temporal and spatial limitations and enabling quantification of functional outcomes, the platforms should provide unique environments that are more biomimetic than single cell type systems while minimizing complex systemic effects of in vivo models. This manuscript details the development and characterization of lab-on-a-chip platforms for stimulating osteocytes and quantifying bone remodeling. Our platforms provide the foundation for a model that can be used to investigate remodeling interactions as a whole or as a standard mechanotransduction tool by which isolated activity can be quantified as a function of load. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. P2X7R-Panx1 Complex Impairs Bone Mechanosignaling under High Glucose Levels Associated with Type-1 Diabetes.

    Science.gov (United States)

    Seref-Ferlengez, Zeynep; Maung, Stephanie; Schaffler, Mitchell B; Spray, David C; Suadicani, Sylvia O; Thi, Mia M

    2016-01-01

    Type 1 diabetes (T1D) causes a range of skeletal problems, including reduced bone density and increased risk for bone fractures. However, mechanisms underlying skeletal complications in diabetes are still not well understood. We hypothesize that high glucose levels in T1D alters expression and function of purinergic receptors (P2Rs) and pannexin 1 (Panx1) channels, and thereby impairs ATP signaling that is essential for proper bone response to mechanical loading and maintenance of skeletal integrity. We first established a key role for P2X7 receptor-Panx1 in osteocyte mechanosignaling by showing that these proteins are co-expressed to provide a major pathway for flow-induced ATP release. To simulate in vitro the glucose levels to which bone cells are exposed in healthy vs. diabetic bones, we cultured osteoblast and osteocyte cell lines for 10 days in medium containing 5.5 or 25 mM glucose. High glucose effects on expression and function of P2Rs and Panx1 channels were determined by Western Blot analysis, quantification of Ca2+ responses to P2R agonists and oscillatory fluid shear stress (± 10 dyne/cm2), and measurement of flow-induced ATP release. Diabetic C57BL/6J-Ins2Akita mice were used to evaluate in vivo effects of high glucose on P2R and Panx1. Western blotting indicated altered P2X7R, P2Y2R and P2Y4R expression in high glucose exposed bone cells, and in diabetic bone tissue. Moreover, high glucose blunted normal P2R- and flow-induced Ca2+ signaling and ATP release from osteocytes. These findings indicate that T1D impairs load-induced ATP signaling in osteocytes and affects osteoblast function, which are essential for maintaining bone health.

  3. P2X7R-Panx1 Complex Impairs Bone Mechanosignaling under High Glucose Levels Associated with Type-1 Diabetes.

    Directory of Open Access Journals (Sweden)

    Zeynep Seref-Ferlengez

    Full Text Available Type 1 diabetes (T1D causes a range of skeletal problems, including reduced bone density and increased risk for bone fractures. However, mechanisms underlying skeletal complications in diabetes are still not well understood. We hypothesize that high glucose levels in T1D alters expression and function of purinergic receptors (P2Rs and pannexin 1 (Panx1 channels, and thereby impairs ATP signaling that is essential for proper bone response to mechanical loading and maintenance of skeletal integrity. We first established a key role for P2X7 receptor-Panx1 in osteocyte mechanosignaling by showing that these proteins are co-expressed to provide a major pathway for flow-induced ATP release. To simulate in vitro the glucose levels to which bone cells are exposed in healthy vs. diabetic bones, we cultured osteoblast and osteocyte cell lines for 10 days in medium containing 5.5 or 25 mM glucose. High glucose effects on expression and function of P2Rs and Panx1 channels were determined by Western Blot analysis, quantification of Ca2+ responses to P2R agonists and oscillatory fluid shear stress (± 10 dyne/cm2, and measurement of flow-induced ATP release. Diabetic C57BL/6J-Ins2Akita mice were used to evaluate in vivo effects of high glucose on P2R and Panx1. Western blotting indicated altered P2X7R, P2Y2R and P2Y4R expression in high glucose exposed bone cells, and in diabetic bone tissue. Moreover, high glucose blunted normal P2R- and flow-induced Ca2+ signaling and ATP release from osteocytes. These findings indicate that T1D impairs load-induced ATP signaling in osteocytes and affects osteoblast function, which are essential for maintaining bone health.

  4. Dating of cremated bones

    NARCIS (Netherlands)

    Lanting, JN; Aerts-Bijma, AT; van der Plicht, J; Boaretto, E.; Carmi, I.

    2001-01-01

    When dating unburnt bone, bone collagen, the organic fraction of the bone, is used. Collagen does not survive the heat of the cremation pyre, so dating of cremated bone has been considered impossible. Structural carbonate in the mineral fraction of the bone, however, survives the cremation process.

  5. Analysis of flow-induced vibration of heat exchanger and steam generator tube bundles using the AECL computer code PIPEAU-2

    International Nuclear Information System (INIS)

    Gorman, D.J.

    1983-12-01

    PIPEAU-2 is a computer code developed at the Chalk River Nuclear Laboratories for the flow-induced vibration analysis of heat exchanger and steam generator tube bundles. It can perform this analysis for straight and 'U' tubes. All the theoretical work underlying the code is analytical rather than numerical in nature. Highly accurate evaluation of the free vibration frequencies and mode shapes is therefore obtained. Using the latest experimentally determined parameters available, the free vibration analysis is followed by a forced vibration analysis. Tube response due to fluid turbulence and vortex shedding is determined, as well as critical fluid velocity associated with fluid-elastic instability

  6. A 3D CFD Simulation and Analysis of Flow-Induced Forces on Polymer Piezoelectric Sensors in a Chinese Liquors Identification E-Nose

    Directory of Open Access Journals (Sweden)

    Yu Gu

    2016-10-01

    Full Text Available Chinese liquors can be classified according to their flavor types. Accurate identification of Chinese liquor flavors is not always possible through professional sommeliers’ subjective assessment. A novel polymer piezoelectric sensor electric nose (e-nose can be applied to distinguish Chinese liquors because of its excellent ability in imitating human senses by using sensor arrays and pattern recognition systems. The sensor, based on the quartz crystal microbalance (QCM principle is comprised of a quartz piezoelectric crystal plate sandwiched between two specific gas-sensitive polymer coatings. Chinese liquors are identified by obtaining the resonance frequency value changes of each sensor using the e-nose. However, the QCM principle failed to completely account for a particular phenomenon: we found that the resonance frequency values fluctuated in the stable state. For better understanding the phenomenon, a 3D Computational Fluid Dynamics (CFD simulation using the finite volume method is employed to study the influence of the flow-induced forces to the resonance frequency fluctuation of each sensor in the sensor box. A dedicated procedure was developed for modeling the flow of volatile gas from Chinese liquors in a realistic scenario to give reasonably good results with fair accuracy. The flow-induced forces on the sensors are displayed from the perspective of their spatial-temporal and probability density distributions. To evaluate the influence of the fluctuation of the flow-induced forces on each sensor and ensure the serviceability of the e-nose, the standard deviation of resonance frequency value (SDF and the standard deviation of resultant forces (SDFy in y-direction (Fy are compared. Results show that the fluctuations of Fy are bound up with the resonance frequency values fluctuations. To ensure that the sensor's resonance frequency values are steady and only fluctuate slightly, in order to improve the identification accuracy of Chinese

  7. Missense Mutations in LRP5 Associated with High Bone Mass Protect the Mouse Skeleton from Disuse- and Ovariectomy-Induced Osteopenia.

    Directory of Open Access Journals (Sweden)

    Paul J Niziolek

    Full Text Available The low density lipoprotein receptor-related protein-5 (LRP5, a co-receptor in the Wnt signaling pathway, modulates bone mass in humans and in mice. Lrp5 knock-out mice have severely impaired responsiveness to mechanical stimulation whereas Lrp5 gain-of-function knock-in and transgenic mice have enhanced responsiveness to mechanical stimulation. Those observations highlight the importance of Lrp5 protein in bone cell mechanotransduction. It is unclear if and how high bone mass-causing (HBM point mutations in Lrp5 alter the bone-wasting effects of mechanical disuse. To address this issue we explored the skeletal effects of mechanical disuse using two models, tail suspension and Botulinum toxin-induced muscle paralysis, in two different Lrp5 HBM knock-in mouse models. A separate experiment employing estrogen withdrawal-induced bone loss by ovariectomy was also conducted as a control. Both disuse stimuli induced significant bone loss in WT mice, but Lrp5 A214V and G171V were partially or fully protected from the bone loss that normally results from disuse. Trabecular bone parameters among HBM mice were significantly affected by disuse in both models, but these data are consistent with DEXA data showing a failure to continue growing in HBM mice, rather than a loss of pre-existing bone. Ovariectomy in Lrp5 HBM mice resulted in similar protection from catabolism as was observed for the disuse experiments. In conclusion, the Lrp5 HBM alleles offer significant protection from the resorptive effects of disuse and from estrogen withdrawal, and consequently, present a potential mechanism to mimic with pharmaceutical intervention to protect against various bone-wasting stimuli.

  8. Dating of cremated bones

    OpenAIRE

    Lanting, JN; Aerts-Bijma, AT; van der Plicht, J; Boaretto, E.; Carmi, I.

    2001-01-01

    When dating unburnt bone, bone collagen, the organic fraction of the bone, is used. Collagen does not survive the heat of the cremation pyre, so dating of cremated bone has been considered impossible. Structural carbonate in the mineral fraction of the bone, however, survives the cremation process. We developed a method of dating cremated bone by accelerator mass spectrometry (AMS), using this carbonate fraction. Here we present results for a variety of prehistoric sites and ages, showing a r...

  9. Bone development

    DEFF Research Database (Denmark)

    Tatara, M.R.; Tygesen, Malin Plumhoff; Sawa-Wojtanowicz, B.

    2007-01-01

    The objective of this study was to determine the long-term effect of alpha-ketoglutarate (AKG) administration during early neonatal life on skeletal development and function, with emphasis on bone exposed to regular stress and used to serve for systemic changes monitoring, the rib. Shropshire ram...... at 146 days of life and five left and right ribs (fourth to eighth) were removed for analysis. The influence of AKG on skeletal system development was evaluated in relation to both geometrical and mechanical properties, as well as quantitative computed tomography (QCT). No significant differences between...... has a long-term effect on skeletal development when given early in neonatal life, and that changes in rib properties serve to improve chest mechanics and functioning in young animals. Moreover, neonatal administration of AKG may be considered as an effective factor enhancing proper development...

  10. Bone grafting: An overview

    Directory of Open Access Journals (Sweden)

    D. O. Joshi

    2010-08-01

    Full Text Available Bone grafting is the process by which bone is transferred from a source (donor to site (recipient. Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of

  11. Bone grafts in dentistry

    Directory of Open Access Journals (Sweden)

    Prasanna Kumar

    2013-01-01

    Full Text Available Bone grafts are used as a filler and scaffold to facilitate bone formation and promote wound healing. These grafts are bioresorbable and have no antigen-antibody reaction. These bone grafts act as a mineral reservoir which induces new bone formation.

  12. Bone scan in rheumatology

    International Nuclear Information System (INIS)

    Morales G, R.; Cano P, R.; Mendoza P, R.

    1993-01-01

    In this chapter a revision is made concerning different uses of bone scan in rheumatic diseases. These include reflex sympathetic dystrophy, osteomyelitis, spondyloarthropaties, metabolic bone diseases, avascular bone necrosis and bone injuries due to sports. There is as well some comments concerning pediatric pathology and orthopedics. (authors). 19 refs., 9 figs

  13. Bone Marrow Transplantation

    Science.gov (United States)

    Bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains immature cells, called stem cells. The ... platelets, which help the blood to clot. A bone marrow transplant is a procedure that replaces a ...

  14. Differences in trabecular bone of leptin-deficient ob/ob mice in response to biomechanical loading.

    Science.gov (United States)

    Heep, Hansjoerg; Wedemeyer, Christian; Wegner, Alexander; Hofmeister, Sebastian; von Knoch, Marius

    2008-06-15

    It is known that bone mineral density (BMD) and the strength of bone is predicted by body mass. Fat mass is a significant predictor of bone mineral density which correlates with body weight. This suggests that body fat regulates bone metabolism first by means of hormonal factors and second that the effects of muscle and loading are signaling factors in mechanotransduction. Leptin, a peptide hormone produced predominantly by white fat cells, is one of these hormonal factors. The aim of this study was to investigate and measure by micro-CT the different effects of weight-bearing on trabecular bone formation in mice without the stimulation of leptin. Animals with an ad-libitum-diet (Group A) were found to increase body weight significantly at the age of six weeks in comparison with lean mice (Group B). From this point on, the difference increased constantly. At the age of twenty weeks the obese mice were almost twice as heavy as the lean mice. Significant statistical differences are shown between the two groups for body weight and bone mineral density. Examination of trabecular bone (BV/TV, trabecular number (Tb.N.), trabecular thickness (Tb.Th.)) revealed that the only statistically significant difference between the two groups was the Tb.N. for the proximal femur. High weight-bearing insignificantly improved all trabecular bone parameters in the obese mice. Compared with the control-diet Group B, the BV/TV and Tb.N. were slightly higher in the controlled-diet Group A, but not the Tb.Th.. However, correlation was found between Tb.N. and BMD on the one hand and body weight on the other hand. biomechanical loading led to decreased bone mineral density by a decrease in the number of trabeculae. Trabecular thickness was not increased by biomechanical loading in growing mice. Decreased body weight in leptin-deficient mice protects against bone loss. This finding is consistent with the principle of light-weight construction of bone. Differences in cortical and trabecular

  15. Anorexia Nervosa and Bone

    Science.gov (United States)

    Misra, Madhusmita; Klibanski, Anne

    2014-01-01

    Anorexia nervosa (AN) is a condition of severe low weight that is associated with low bone mass, impaired bone structure and reduced bone strength, all of which contribute to increased fracture risk., Adolescents with AN have decreased rates of bone accrual compared with normal-weight controls, raising addition concerns of suboptimal peak bone mass and future bone health in this age group. Changes in lean mass and compartmental fat depots, hormonal alterations secondary to nutritional factors contribute to impaired bone metabolism in AN. The best strategy to improve bone density is to regain weight and menstrual function. Oral estrogen-progesterone combinations are not effective in increasing bone density in adults or adolescents with AN, and transdermal testosterone replacement is not effective in increasing bone density in adult women with AN. However, physiologic estrogen replacement as transdermal estradiol with cyclic progesterone does increase bone accrual rates in adolescents with AN to approximate that in normal-weight controls, leading to a maintenance of bone density Z-scores. A recent study has shown that risedronate increases bone density at the spine and hip in adult women with AN. However, bisphosphonates should be used with great caution in women of reproductive age given their long half-life and potential for teratogenicity, and should be considered only in patients with low bone density and clinically significant fractures when non-pharmacological therapies for weight gain are ineffective. Further studies are necessary to determine the best therapeutic strategies for low bone density in AN. PMID:24898127

  16. Numerical simulation of flow induced by a pitched blade turbine. Comparison of the sliding mesh technique and an averaged source term method

    Energy Technology Data Exchange (ETDEWEB)

    Majander, E.O.J.; Manninen, M.T. [VTT Energy, Espoo (Finland)

    1996-12-31

    The flow induced by a pitched blade turbine was simulated using the sliding mesh technique. The detailed geometry of the turbine was modelled in a computational mesh rotating with the turbine and the geometry of the reactor including baffles was modelled in a stationary co-ordinate system. Effects of grid density were investigated. Turbulence was modelled by using the standard k-{epsilon} model. Results were compared to experimental observations. Velocity components were found to be in good agreement with the measured values throughout the tank. Averaged source terms were calculated from the sliding mesh simulations in order to investigate the reliability of the source term approach. The flow field in the tank was then simulated in a simple grid using these source terms. Agreement with the results of the sliding mesh simulations was good. Commercial CFD-code FLUENT was used in all simulations. (author)

  17. Regulation of Bone Metabolism

    Directory of Open Access Journals (Sweden)

    Maryam Shahi

    2017-05-01

    Full Text Available Bone is formed through the processes of endochondral and intramembranous ossification. In endochondral ossification primary mesenchymal cells differentiate to chondrocytes and then are progressively substituted by bone, while in intramembranous ossification mesenchymal stem cells (MSCs differentiate directly into osteoblasts to form bone. The steps of osteogenic proliferation, differentiation, and bone homeostasis are controlled by various markers and signaling pathways. Bone needs to be remodeled to maintain integrity with osteoblasts, which are bone-forming cells, and osteoclasts, which are bone-degrading cells. In this review we considered the major factors and signaling pathways in bone formation; these include fibroblast growth factors (FGFs, bone morphogenetic proteins (BMPs, wingless-type (Wnt genes, runt-related transcription factor 2 (RUNX2 and osteoblast-specific transcription factor (osterix or OSX.

  18. Bone disease in hypoparathyroidism.

    Science.gov (United States)

    Clarke, Bart L

    2014-07-01

    Hypoparathyroidism is a rare disorder that may be acquired or inherited. Postsurgical hypoparathyroidism is responsible for the majority of acquired hypoparathyroidism. Bone disease occurs in hypoparathyroidism due to markedly reduced bone remodeling due to the absence or low levels of parathyroid hormone. Chronically reduced bone turnover in patients with hypoparathyroidism typically leads to higher bone mass than in age- and sex-matched controls. Whether this increased bone density reduces fracture risk is less certain, because while increased bone mineralization may be associated with increased brittleness of bone, this does not appear to be the case in hypoparathyroidism. Treatment of hypoparathyroidism with recombinant parathyroid hormone may reduce bone mineral density but simultaneously strengthen the mechanical properties of bone.

  19. Bone-Immune Cell Crosstalk: Bone Diseases

    Directory of Open Access Journals (Sweden)

    Giorgio Mori

    2015-01-01

    Full Text Available Bone diseases are associated with great morbidity; thus, the understanding of the mechanisms leading to their development represents a great challenge to improve bone health. Recent reports suggest that a large number of molecules produced by immune cells affect bone cell activity. However, the mechanisms are incompletely understood. This review aims to shed new lights into the mechanisms of bone diseases involving immune cells. In particular, we focused our attention on the major pathogenic mechanism underlying periodontal disease, psoriatic arthritis, postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, metastatic solid tumors, and multiple myeloma.

  20. Macrophages and bone inflammation

    Directory of Open Access Journals (Sweden)

    Qiaoli Gu

    2017-07-01

    Full Text Available Bone metabolism is tightly regulated by the immune system. Accelerated bone destruction is observed in many bone diseases, such as rheumatoid arthritis, fracture, and particle-induced osteolysis. These pathological conditions are associated with inflammatory responses, suggesting the contribution of inflammation to bone destruction. Macrophages are heterogeneous immune cells and are polarized into the proinflammatory M1 and antiinflammatory M2 phenotypes in different microenvironments. The cytokines produced by macrophages depend on the macrophage activation and polarization. Macrophages and macrophage-derived cytokines are important to bone loss in inflammatory bone disease. Recent studies have shown that macrophages can be detected in bone tissue and interact with bone cells. The interplay between macrophages and bone cells is critical to bone formation and repair. In this article, we focus on the role of macrophages in inflammatory bone diseases, as well as discuss the latest studies about macrophages and bone formation, which will provide new insights into the therapeutic strategy for bone disease.

  1. Bone mineral density test

    Science.gov (United States)

    BMD test; Bone density test; Bone densitometry; DEXA scan; DXA; Dual-energy x-ray absorptiometry; p-DEXA; Osteoporosis - BMD ... need to undress. This scan is the best test to predict your risk of fractures, especially of ...

  2. Temporal bone imaging

    International Nuclear Information System (INIS)

    Shaffer, K.A.

    1987-01-01

    Although pluridirectional tomography had been the standard method to evaluate the temporal bone, computed tomography has replaced it for nearly all applications. Magnetic resonance imaging can demonstrate nonosseous temporal bone structures as well

  3. Bone Marrow Diseases

    Science.gov (United States)

    ... that help with blood clotting. With bone marrow disease, there are problems with the stem cells or ... marrow makes too many white blood cells Other diseases, such as lymphoma, can spread into the bone ...

  4. Bone substitute biomaterials

    CERN Document Server

    Mallick, K

    2014-01-01

    Bone substitute biomaterials are fundamental to the biomedical sector, and have recently benefitted from extensive research and technological advances aimed at minimizing failure rates and reducing the need for further surgery. This book reviews these developments, with a particular focus on the desirable properties for bone substitute materials and their potential to encourage bone repair and regeneration. Part I covers the principles of bone substitute biomaterials for medical applications. One chapter reviews the quantification of bone mechanics at the whole-bone, micro-scale, and non-scale levels, while others discuss biomineralization, osteoductivization, materials to fill bone defects, and bioresorbable materials. Part II focuses on biomaterials as scaffolds and implants, including multi-functional scaffolds, bioceramics, and titanium-based foams. Finally, Part III reviews further materials with the potential to encourage bone repair and regeneration, including cartilage grafts, chitosan, inorganic poly...

  5. What causes bone loss?

    Science.gov (United States)

    ... Paula FJA, Black DM, Rosen CJ. Osteoporosis and bone biology. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology . 13th ed. Philadelphia, PA: ... HM. Bone development and remodeling. In: Jameson JL, De Groot ...

  6. Gracile bone dysplasias

    Energy Technology Data Exchange (ETDEWEB)

    Kozlowski, Kazimierz [Department of Medical Imaging, The Children' s Hospital at Westmead, Locked Bag 4001, Westmead 2145, NSW (Australia); Masel, John [Department of Radiology, Royal Children' s Hospital, Brisbane (Australia); Sillence, David O. [Department of Paediatrics and Child Health, The University of Sydney (Australia); Arbuckle, Susan [Department of Anatomical Pathology, The Children' s Hospital at Westmead, NSW (Australia); Juttnerova, Vera [Oddeleni Lekarske Genetiky, Hradec Kralove (Czech Republic)

    2002-09-01

    Gracile bone dysplasias constitute a group of disorders characterised by extremely slender bones with or without fractures. We report four newborns, two of whom showed multiple fractures. Two babies had osteocraniostenosis and one had features of oligohydramnios sequence. The diagnosis in the fourth newborn, which showed thin long bones and clavicles and extremely thin, poorly ossified ribs, is uncertain. Exact diagnosis of a gracile bone dysplasia is important for genetic counselling and medico-legal reasons. (orig.)

  7. [Artificial bone substitutes].

    Science.gov (United States)

    Koníček, Petr

    Bone tissue substitutes are divided into basic classification with its pros and cons described. Arteficial bone grafts are especially pointed out in article, publishing our own experience with two specific synthetic preps. Finally there is a blink in the near future of bone tissue augmentation.

  8. (unicameral) bone cysts

    African Journals Online (AJOL)

    When encountering a radiologically benign lucent bone lesion in a child, a simple bone cyst is a reasonable diagnostic consideration. Simple or unicameral bone cysts are expansile, serous-fluid-containing defects, that are not true neoplasms. Peak age ranges between 3 and 14 years in. 80% of cases. The incidence is ...

  9. Long-term potentiation in bone – a role for glutamate in strain-induced cellular memory?

    Directory of Open Access Journals (Sweden)

    Genever Paul G

    2003-07-01

    Full Text Available Abstract Background The adaptive response of bone cells to mechanical strain is a primary determinant of skeletal architecture and bone mass. In vivo mechanical loading induces new bone formation and increases bone mineral density whereas disuse, immobilisation and weightlessness induce bone loss. The potency of mechanical strain is such that a single brief period of loading at physiological strain magnitude is able to induce a long-lasting osteogenic response that lasts for days. Although the process of mechanotransduction in bone is incompletely understood, observations that responses to mechanical strain outlast the duration of stimulation necessitate the existence of a form of cellular memory through which transient strain episodes are recorded, interpreted and remembered by bone cells. Recent evidence supports the existence of a complex multicellular glutamate-signalling network in bone that shares functional similarities to glutamatergic neurotransmission in the central nervous system. In neurones, these signalling molecules coordinate synaptic communication required to support learning and memory formation, through a complex process of long-term potentiation. Presentation of the hypothesis We hypothesise that osteoblasts use a cellular mechanism similar or identical to neuronal long-term potentiation in the central nervous system to mediate long-lasting changes in osteogenesis following brief periods of mechanical strain. Testing the hypothesis N-methyl-D-aspartate (NMDA receptor antagonism should inhibit the saturating response of mechanical strain and reduce the enhanced osteogenicity of segregated loading to that of an equivalent period of uninterrupted loading. Changes in α-amino-3-hydroxy-5-methyl-isoxazole propionate (AMPA receptor expression, localisation and electrophysiological responses should be induced by mechanical strain and inhibited by modulators of neuronal long-term potentiation. Implications of the hypothesis If true

  10. Cytology of Bone.

    Science.gov (United States)

    Barger, Anne M

    2017-01-01

    Cytology of bone is a useful diagnostic tool. Aspiration of lytic or proliferative lesions can assist with the diagnosis of inflammatory or neoplastic processes. Bacterial, fungal, and protozoal organisms can result in significant osteomyelitis, and these organisms can be identified on cytology. Neoplasms of bone including primary bone tumors such as osteosarcoma, chondrosarcoma, fibrosarcoma, synovial cell sarcoma, and histiocytic sarcoma and tumors of bone marrow including plasma cell neoplasia and lymphoma and metastatic neoplasia can result in significant bone lysis or proliferation and can be diagnosed effectively with cytology. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Bone disease in diabetes

    DEFF Research Database (Denmark)

    Shanbhogue, Vikram V.; Hansen, Stinus; Frost, Morten

    2017-01-01

    Type 1 and type 2 diabetes are generally accepted to be associated with increased bone fracture risk. However, the pathophysiological mechanisms of diabetic bone disease are poorly understood, and whether the associated increased skeletal fragility is a comorbidity or a complication of diabetes...... remains under debate. Although there is some indication of a direct deleterious effect of microangiopathy on bone, the evidence is open to question, and whether diabetic osteopathy can be classified as a chronic, microvascular complication of diabetes remains uncertain. Here, we review the current...... knowledge of potential contributory factors to diabetic bone disease, particularly the association between diabetic microangiopathy and bone mineral density, bone structure, and bone turnover. Additionally, we discuss and propose a pathophysiological model of the effects of diabetic microvascular disease...

  12. Bone regeneration in dentistry

    Science.gov (United States)

    Tonelli, Paolo; Duvina, Marco; Barbato, Luigi; Biondi, Eleonora; Nuti, Niccolò; Brancato, Leila; Rose, Giovanna Delle

    2011-01-01

    Summary The edentulism of the jaws and the periodontal disease represent conditions that frequently leads to disruption of the alveolar bone. The loss of the tooth and of its bone of support lead to the creation of crestal defects or situation of maxillary atrophy. The restoration of a functional condition involves the use of endosseous implants who require adequate bone volume, to deal with the masticatory load. In such situations the bone need to be regenerated, taking advantage of the biological principles of osteogenesis, osteoinduction and osteoconduction. Several techniques combine these principles with different results, due to the condition of the bone base on which we operate changes, the surgical technique that we use, and finally for the bone metabolic conditions of the patient who can be in a state of systemic osteopenia or osteoporosis; these can also affect the result of jaw bone reconstruction. PMID:22461825

  13. Bone stress injuries

    Energy Technology Data Exchange (ETDEWEB)

    Kiuru, M.J.; Pihlajamaeki, H.K.; Ahovuo, J.A. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology

    2004-05-01

    Bone stress injuries are due to cyclical overuse of the bone. They are relatively common in athletes and military recruits but also among otherwise healthy people who have recently started new or intensive physical activity. Diagnosis of bone stress injuries is based on the patient's history of increased physical activity and on imaging findings. The general symptom of a bone stress injury is stress-related pain. Bone stress injuries are difficult to diagnose based only on a clinical examination because the clinical symptoms may vary depending on the phase of the pathophysiological spectrum in the bone stress injury. Imaging studies are needed to ensure an early and exact diagnosis, because if the diagnosis is not delayed most bone stress injuries heal well without complications.

  14. Bone allografting in children

    Science.gov (United States)

    Sadovoy, M. A.; Kirilova, I. A.; Podorognaya, V. T.; Matsuk, S. A.; Novoselov, V. P.; Moskalev, A. V.; Bondarenko, A. V.; Afanasev, L. M.; Gubina, E. V.

    2017-09-01

    A total of 522 patients with benign and intermediate bone tumors of various locations, aged 1 to 15 years, were operated in the period from 1996 to 2016. To diagnose skeleton tumors, we used clinical observation, X-ray, and, if indicated, tomography and tumor site biopsy. In the extensive bone resection, we performed bone reconstruction with the replacement of a defect with an allograft (bone strips, deproteinized and spongy grafts), sometimes in the combination with bone autografting. After segmental resection, the defects were filled with bone strips in the form of matchstick grafts; the allografts were received from the Laboratory for Tissue Preparation and Preservation of the Novosibirsk Research Institute of Traumatology and Orthopedics. According to the X-ray data, a complete reorganization of bone grafts occurred within 1.5 to 3 years. The long-term result was assessed as good.

  15. Bone scintiscanning updated.

    Science.gov (United States)

    Lentle, B C; Russell, A S; Percy, J S; Scott, J R; Jackson, F I

    1976-03-01

    Use of modern materials and methods has given bone scintiscanning a larger role in clinical medicine, The safety and ready availability of newer agents have led to its greater use in investigating both benign and malignant disease of bone and joint. Present evidence suggests that abnormal accumulation of 99mTc-polyphosphate and its analogues results from ionic deposition at crystal surfaces in immature bone, this process being facilitated by an increase in bone vascularity. There is, also, a component of matrix localization. These factors are in keeping with the concept that abnormal scintiscan sites represent areas of increased osteoblastic activity, although this may be an oversimplification. Increasing evidence shows that the bone scintiscan is more sensitive than conventional radiography in detecting focal disease of bone, and its ability to reflect the immediate status of bone further complements radiographic findings. The main limitation of this method relates to nonspecificity of the results obtained.

  16. BONES WITH BIOCERAMICS

    Directory of Open Access Journals (Sweden)

    Wijianto Wijianto

    2017-01-01

    Full Text Available This paper discuss about ceramics in application as bone implant. Bioceramics for instance Hydroxyapatite, usually is abbreviated with HA or HAp, is a mineral that is very good physical properties as bone replacement in human body. To produce Hydroxyapatite, coating process is used which have good potential as they can exploit the biocompatible and bone bonding properties of the ceramic. There are many advantages and disadvantages of bioceramics as bone implant. Advantages of hydroxyapatite as bone implant are rapidly integrated into the human body, and is most interesting property that will bond to bone forming indistinguishable unions. On contrary, disadvantages of hydroxyapatite as bone implant are poor mechanical properties (in particular fatigue properties mean that hydroxyapatite cannot be used in bulk form for load bearing applications such as orthopaedics and poor adhesion between the calcium phosphate coating and the material implant will occur.

  17. Flow-induced [Ca2+]i increase depends on nucleotide release and subsequent purinergic signaling in the intact nephron

    DEFF Research Database (Denmark)

    Juul Jensen, Mikkel E.; Odgaard, Elvin V. P.; Christensen, Mette Høgh

    2007-01-01

    that the flow-induced [Ca2+]i response in the renal tubule involves mechanically stimulated nucleotide release. This study investigated (1) the expression of P2 receptors in mouse medullary thick ascending limb (mTAL) using P2Y2 receptor knockout (KO) mice, (2) whether flow increases induce [Ca2+]i elevations...... in mTAL, and (3) whether this flow response is affected in mice that are deplete of the main purinergic receptor. [Ca2+]i was imaged in perfused mTAL with fura-2 or fluo-4. It is shown that luminal and basolateral P2Y2 receptors are the main purinergic receptor in this segment. Moreover, the data...... suggest presence of basolateral P2X receptors. Increases of tubular flow were imposed by promptly rising the inflow pressure, which triggered a marked increase of [Ca2+]i. This [Ca2+]i response was significantly reduced in P2Y2 receptor KO tubules (fura-2 ratio increase WT 0.44 +/- 0.09 [n = 28] versus KO...

  18. Experimental Investigation of the Effect of Radial Gap and Impeller Blade Exit on Flow-Induced Vibration at the Blade-Passing Frequency in a Centrifugal Pump

    Directory of Open Access Journals (Sweden)

    A. Al-Qutub

    2009-01-01

    Full Text Available It has been recognized that the pressure pulsation excited by rotor-stator interaction in large pumps is strongly influenced by the radial gap between impeller and volute diffusers/tongues and the geometry of impeller blade at exit. This fluid-structure interaction phenomenon, as manifested by the pressure pulsation, is the main cause of flow-induced vibrations at the blade-passing frequency. In the present investigation, the effects of the radial gap and flow rate on pressure fluctuations, vibration, and pump performance are investigated experimentally for two different impeller designs. One impeller has a V-shaped cut at the blade's exit, while the second has a straight exit (without the V-cut. The experimental findings showed that the high vibrations at the blade-passing frequency are primarily raised by high pressure pulsation due to improper gap design. The existence of V-cut at blades exit produces lower pressure fluctuations inside the pump while maintaining nearly the same performance. The selection of proper radial gap for a given impeller-volute combination results in an appreciable reduction in vibration levels.

  19. Evaluation of Flow-Induced Dynamic Stress and Vibration of Volute Casing for a Large-Scale Double-Suction Centrifugal Pump

    Directory of Open Access Journals (Sweden)

    Fu-Jun Wang

    2013-01-01

    Full Text Available The transient analysis was carried out to investigate the dynamic stress and vibration of volute casing for a large double-suction centrifugal pump by using the transient fluid-structure interaction theory. The flow pulsations at flow rate ranging from 60% to 100% of the nominal flow rate (Qd were taken as the boundary conditions for FEM analysis of the pump volute casing structure. The results revealed that, for all operating conditions, the maximum stress located at the volute tongue region, whereas the maximum vibration displacement happened close to the shaft hole region. It was also found that the blade passing frequency and its harmonics were dominant in the variations of dynamic stress and vibration displacement. The amplitude of the dominant frequency for the maximum stress detected at 0.6 Qd was 1.14 times that at Qd, lower than the related difference observed for pressure fluctuations (3.23 times. This study provides an effective method to quantify the flow-induced structural dynamic characteristics for a large-scale double-suction pump. It can be used to direct the hydraulic and structural design and stable operation, as well as fatigue life prediction for large-scale pumps.

  20. Visualization investigation of acoustic and flow-induced vibration in main stream lines using a high-time-resolved PIV technique

    International Nuclear Information System (INIS)

    Li, Yanrong; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    Systems with closed side-branches are liable to an excitation of sound, as called cavity tone. It may occur in pipe branches leading to safety valves or to boiler relief valves. The outbreak mechanism of the cavity tone has been known by phase-averaged measurement in previous researches, while the relation between sound propagation and flow field is still unclear due to the difficulty of detecting instantaneous velocity field. High-time-resolved PIV has a possibility to analyze the velocity field and the relation mentioned above. In this study, flow-induced acoustic resonance of piping system containing closed side-branches was investigated experimentally. A high-time-resolved PIV technique was applied to measure a gas-flow in a cavity. Air flow containing oil mist as tracer particles was measured using a high frequency pulse laser and a high speed camera. The present investigation on the coaxial closed side-branches is the first rudimentary study to visualize the fluid flow two-dimensionally in the cross-section by using PIV and to measure the pressure at the downstream side opening of the cavity by microphone. The fluid flows at different points in the cavity interact with some phase differences and the relation was clarified. (author)

  1. Analysis on Flow Induced Motion of Cylinders with Different Cross Sections and the Potential Capacity of Energy Transference from the Flow

    Directory of Open Access Journals (Sweden)

    Jijian Lian

    2017-01-01

    Full Text Available The energy in flow induced motion (FIM was harnessed in recent years. In this study, the energy transfer ratio was derived to estimate the energy transference from the flow to the FIM. Then the FIM characteristics and energy transference of cylinders with different cross sections were experimentally investigated. The main findings are listed as follows. (a Circular cylinders and diamond prisms both present a self-limited motion. The maximum amplitude ratio of circular cylinder is around 1~1.2 which is higher than that of diamond prism (0.4~0.5. (b Triangle prisms and right square prisms present a self-unlimited motion. For triangle prism, amplitude ratio increases over 1.8; for right square prisms, amplitude ratio reaches 1.2. (c The maximum transfer ratios of circular cylinder and triangle prism are 80% and 57%, respectively, which are much higher than those of other prisms, indicating that circular cylinder and triangle prism have better performances in energy transference. (d The transfer ratio is strongly dependent on the damping and mass; higher damping or mass will promote a higher transfer ratio. (e Beyond the critical transfer ratios, amplitude variation coefficients are around 10%~30% resulting in a better performance in stationarity.

  2. [Bone homeostasis and Mechano biology.

    Science.gov (United States)

    Nakashima, Tomoki

    The weight-bearing exercises help to build bones and to maintain them strength. Bone is constantly renewed by the balanced action of osteoblastic bone formation and osteoclastic bone resorption both of which mainly occur at the bone surface. This restructuring process called "bone remodeling" is important not only for normal bone mass and strength, but also for mineral homeostasis. Bone remodeling is stringently regulated by communication between bone component cells such as osteoclasts, osteoblasts and osteocytes. An imbalance of this process is often linked to various bone diseases. During bone remodeling, resorption by osteoclasts precedes bone formation by osteoblasts. Based on the osteocyte location within the bone matrix and the cellular morphology, it is proposed that osteocytes potentially contribute to the regulation of bone remodeling in response to mechanical and endocrine stimuli.

  3. Toxicokinetics of bone lead.

    Science.gov (United States)

    Rabinowitz, M B

    1991-02-01

    This article discusses bone as a source of lead to the rest of the body and as a record of past lead exposure. Bone lead levels generally increase with age at rates dependent on the skeletal site and lead exposure. After occupational exposure, the slow decline in blood lead, a 5- to 19-year half-life, reflects the long skeletal half-life. Repeated measurements of bone lead demonstrate the slow elimination of lead from bone. Stable isotope ratios have revealed many details of skeletal uptake and subsequent release. The bulk turnover rates for compact bone are about 2% per year and 8% for spine. Turnover activity varies with age and health. Even though lead approximates calcium, radium, strontium, barium, fluorine, and other bone seekers, the rates for each are different. A simple, two-pool (bone and blood) kinetic model is presented with proposed numerical values for the changes in blood lead levels that occur with changes in turnover rates. Two approaches are offered to further quantify lead turnover. One involves a study of subjects with known past exposure. Changes in the ratio of blood lead to bone lead with time would reflect the course of bone lead availability. Also, stable isotopes and subjects who move from one geographical area to another offer opportunities. Sequential isotope measurements would indicate how much of the lead in blood is from current exposure or bone stores, distinct from changes in absorption or excretion.

  4. Biophotonics and Bone Biology

    Science.gov (United States)

    Zimmerli, Gregory; Fischer, David; Asipauskas, Marius; Chauhan, Chirag; Compitello, Nicole; Burke, Jamie; Tate, Melissa Knothe

    2004-01-01

    One of the more-serious side effects of extended space flight is an accelerated bone loss [Bioastronautics Critical Path Roadmap, http://research.hq.nasa.gov/code_u/bcpr/index.cfm]. Rates of bone loss are highest in the weight-bearing bones of the hip and spine regions, and the average rate of bone loss as measured by bone mineral density measurements is around 1.2% per month for persons in a microgravity environment. It shows that an extrapolation of the microgravity induced bone loss rates to longer time scales, such as a 2.5 year round-trip to Mars (6 months out at 0 g, 1.5 year stay on Mars at 0.38 g, 6 months back at 0 g), could severely compromise the skeletal system of such a person.

  5. Flow induced vibrations of piping

    International Nuclear Information System (INIS)

    Gibert, R.J.; Axisa, F.

    1977-01-01

    In order to design the supports of piping systems, estimations of the vibrations induced by the fluid conveyed through the pipes are generally needed. For that purpose it is necessary to calculate the model parameters of liquid containing pipes. In most computer codes, fluid effects are accounted for just by adding the fuid mass to the structure. This may lead to serious errors.- Inertial effects from the fluid are not correctly evaluated especially in the case of bended or of non-uniform section pipes. Fluid boundary conditions are simply ignored. - In many practical problems fluid compressibility cannot be negelcted, even in the low frequencies domain which corresponds to efficient excitation by turbulent sources of the flow. This paper presents a method to take into account these efects, by solving a coupled mechanical acoustical problem: the computer code TEDEL of the C.E.A./D.E.M.T. System, based on the finite-elements method, has been extended to calculate simultaneously the pressure fluctuations in the fluid and the vibrations of the pipe. (Auth.)

  6. Flow induced vibrations of piping

    International Nuclear Information System (INIS)

    Gibert, R.J.; Axisa, F.

    1977-01-01

    This paper presents a method to take into account the inertial effects and the fluid compressibility by solving a coupled mechanical-acoustical problem: the computer code TEDEL of the C.E.A./D.E.M.T. System, based on the finite-element method, has been extended to calculate simultaneously the pressure fluctuations in the fluid and the vibrations of the pipe. By this way the mechanical-acoustical coupled eigenmodes of any piping system can be obtained. These eigenmodes are used to determine the response of the system to various sources (acoustical sources or forces exciting directly the structure). Equations have been written in the hypothesis that acoustical wave lengths remain large compared to the diameter of the pipe. Indeed this is largely verified in almost practical cases. The method has been checked by an experiment performed on the GASCOGNE loop at D.E.M.T. The piping system under test consist of a tube with four elbows. The circuit is ended at each extremity by a large vessel which performs acoustical isolation by generating modes for the pressure. Excitation of the circuit is caused by a valve located near the downstream vessel. This provide an efficient localised broad band acoustical source. The comparison between the test results and the calculations has shown that the low frequency resonant characteristics of the pipe and the vibrational amplitude at various flow-rates can be correctly predicted [fr

  7. The petrous bone

    DEFF Research Database (Denmark)

    Jørkov, Marie Louise Schjellerup; Heinemeier, Jan; Lynnerup, Niels

    2009-01-01

    Intraskeletal variation in the composition of carbon (delta(13)C) and nitrogen (delta(15)N) stable isotopes measured in collagen is tested from various human bones and dentine. Samples were taken from the femur, rib, and petrous part of the temporal bone from well-preserved skeletons of both adul...... of this study it is believed the petrous bone may be a new useful bone element and a supplement or a proxy for teeth in the analysis of early dietary patterns as it may reflect diet in fetal stages and early years of life....

  8. Toxicokinetics of bone lead.

    OpenAIRE

    Rabinowitz, M B

    1991-01-01

    This article discusses bone as a source of lead to the rest of the body and as a record of past lead exposure. Bone lead levels generally increase with age at rates dependent on the skeletal site and lead exposure. After occupational exposure, the slow decline in blood lead, a 5- to 19-year half-life, reflects the long skeletal half-life. Repeated measurements of bone lead demonstrate the slow elimination of lead from bone. Stable isotope ratios have revealed many details of skeletal uptake a...

  9. Hypercalciuric Bone Disease

    Science.gov (United States)

    Favus, Murray J.

    2008-09-01

    Hypercalciuria plays an important causal role in many patients with calcium oxalate (CaOx) stones. The source of the hypercalciuria includes increased intestinal Ca absorption and decreased renal tubule Ca reabsorption. In CaOx stone formers with idiopathic hypercalciuria (IH), Ca metabolic balance studies have revealed negative Ca balance and persistent hypercalciuria in the fasting state and during low dietary Ca intake. Bone resorption may also contribute to the high urine Ca excretion and increase the risk of bone loss. Indeed, low bone mass by DEXA scanning has been discovered in many IH patients. Thiazide diuretic agents reduce urine Ca excretion and may increase bone mineral density (BMD), thereby reducing fracture risk. Dietary Ca restriction that has been used unsuccessfully in the treatment of CaOx nephrolithiasis in the past may enhance negative Ca balance and accelerate bone loss. DEXA scans may demonstrate low BMD at the spine, hip, or forearm, with no predictable pattern. The unique pattern of bone histologic changes in IH differs from other causes of low DEXA bone density including postmenopausal osteoporosis, male hypogonadal osteoporosis, and glucocorticoid-induced osteoporosis. Hypercalciuria appears to play an important pathologic role in the development of low bone mass, and therefore correction of urine Ca losses should be a primary target for treatment of the bone disease accompanying IH.

  10. Traumatic bone cyst, idiopathic origin

    African Journals Online (AJOL)

    GB

    BACKGROUND: Traumatic bone cyst (TBC) is an uncommon non-epithelial lined cavity of the jaws. Traumatic bone cysts have been reported in the literature under a variety of names: solitary bone cyst, haemorrhagic bone cyst, extravasation cyst and simple bone cyst. The multitude of names applied to this lesion implies ...

  11. Extraskeletal and intraskeletal new bone formation induced by demineralized bone matrix combined with bone marrow cells

    International Nuclear Information System (INIS)

    Lindholm, T.S.; Nilsson, O.S.; Lindholm, T.C.

    1982-01-01

    Dilutions of fresh autogenous bone marrow cells in combination with allogeneic demineralized cortical bone matrix were tested extraskeletally in rats using roentgenographic, histologic, and 45 Ca techniques. Suspensions of bone marrow cells (especially diluted 1:2 with culture media) combined with demineralized cortical bone seemed to induce significantly more new bone than did demineralized bone, bone marrow, or composite grafts with whole bone marrow, respectively. In a short-term spinal fusion experiment, demineralized cortical bone combined with fresh bone marrow produced new bone and bridged the interspace between the spinous processes faster than other transplantation procedures. The induction of undifferentiated host cells by demineralized bone matrix is further complemented by addition of autogenous, especially slightly diluted, bone marrow cells

  12. Study on the annular leakage-flow-induced vibrations. 1st Report. Stability for translational and rotational single-degree-of-freedom systems; Kanjo sukimaryu reiki shindo ni kansuru kenkyu. 1. Heishin oyobi kaiten 1 jiyudokei no anteise

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.W. [Hitachi, Ltd., Tokyo (Japan); Kaneko, S. [The University of Tokyo, Tokyo (Japan); Hayama, S. [Toyama Prefectural University, Toyama (Japan)

    1999-07-25

    This study reports the stability of annular leakage-flow-induced vibrations. The pressure distribution of fluid between a fixed outer cylinder and a vibrating inner cylinder was obtained in the case of a translationally and rotationally coupled motion of the inner cylinder. The unsteady fluid force acting on the inner cylinder in the case of translational and rotational single-degree-of-freedom vibrations was then expressed in terms proportional to the acceleration, velocity, and displacement. Then the critical flow rate (at which stability was lost) was determined for an annular leakage-flow-induced vibration. Finally, the stability was investigated theoretically. It is known that instability will occur in the case of a divergent passage, but the critical flow rate depends on the passage increment in a limited range: the eccentricity of the passage and the pressure loss factor at the inlet of the passage lower the stability. (author)

  13. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... the body. X-rays are the oldest and most frequently used form of medical imaging. A bone ... bones. top of page How should I prepare? Most bone x-rays require no special preparation. You ...

  14. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... is commonly used to diagnose fractured bones or joint dislocation. Bone x-rays are the fastest and ... to view and assess bone fractures, injuries and joint abnormalities. This exam requires little to no special ...

  15. Bone-building exercise (image)

    Science.gov (United States)

    Exercise plays an important role in the retention of bone density in the aging person. Studies show that exercises requiring muscles to pull on bones cause the bones to retain and possibly gain density.

  16. Pregnancy, Breastfeeding, and Bone Health

    Science.gov (United States)

    ... go on to optimize their bone mass. Teen pregnancy and bone health. Teenage mothers may be at especially high risk for bone loss during pregnancy and for osteoporosis later in life. Unlike older ...

  17. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... of bone cancer . locate foreign objects in soft tissues around or in bones. top of page How ... bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow more ...

  18. Biologicals and bone loss

    NARCIS (Netherlands)

    Krieckaert, C.L.M.; Lems, W.F.

    2012-01-01

    Inflammatory joint diseases are associated with extra-articular side effects including bone involvement.There is an increased risk of osteoporotic fractures. The pathogeneses of local and generalized bone loss share a common pathway. Early and active rheumatoid arthritis is associated with

  19. Menopause and Bone Loss

    Science.gov (United States)

    ... calcium supplement if necessary. • Vitamin D. Your body needs vitamin D to absorb calcium and move it into ... bone density test? • Should I take calcium and vitamin D supplements? How much do I need? • Do I need medication for my bone loss? • ...

  20. Pseudoanaplastic tumors of bone

    International Nuclear Information System (INIS)

    Bahk, Won-Jong; Mirra, Joseph M.

    2004-01-01

    To discuss the concept of pseudoanaplastic tumors of bone, which pathologically show hyperchromatism and marked pleomorphism with quite enlarged, pleomorphic nuclei, but with no to extremely rare, typical mitoses, and to propose guidelines for their diagnosis. From a database of 4,262 bone tumors covering from 1971 to 2001, 15 cases of pseudoanaplastic bone tumors (0.35% of total) were retrieved for clinical, radiographic and pathologic review. Postoperative follow-up after surgical treatment was at least 3 years and a maximum of 7 years. There were eight male and seven female patients. Their ages ranged from 10 to 64 years with average of 29.7 years. Pathologic diagnoses of pseudoanaplastic variants of benign bone tumors included: osteoblastoma (4 cases), giant cell tumor (4 cases), chondromyxoid fibroma (3 cases), fibrous dysplasia (2 cases), fibrous cortical defect (1 case) and aneurysmal bone cyst (1 case). Radiography of all cases showed features of a benign bone lesion. Six cases, one case each of osteoblastoma, fibrous dysplasia, aneurysmal bone cyst, chondromyxoid fibroma, giant cell tumor and osteoblastoma, were initially misdiagnosed as osteosarcoma. The remaining cases were referred for a second opinion to rule out sarcoma. Despite the presence of significant cytologic aberrations, none of our cases showed malignant behavior following simple curettage or removal of bony lesions. Our observation justifies the concept of pseudoanaplasia in some benign bone tumors as in benign soft tissue tumors, especially in their late evolutionary stage when bizarre cytologic alterations strongly mimic a sarcoma. (orig.)

  1. Pseudoanaplastic tumors of bone

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Won-Jong [Uijongbu St. Mary Hospital, The Catholic University of Korea, Department of Orthopaedic Surgery, Gyunggido, 480-821 (Korea); Mirra, Joseph M. [Orthopaedic Hospital, Orthopedic Oncology, Los Angeles, California (United States)

    2004-11-01

    To discuss the concept of pseudoanaplastic tumors of bone, which pathologically show hyperchromatism and marked pleomorphism with quite enlarged, pleomorphic nuclei, but with no to extremely rare, typical mitoses, and to propose guidelines for their diagnosis. From a database of 4,262 bone tumors covering from 1971 to 2001, 15 cases of pseudoanaplastic bone tumors (0.35% of total) were retrieved for clinical, radiographic and pathologic review. Postoperative follow-up after surgical treatment was at least 3 years and a maximum of 7 years. There were eight male and seven female patients. Their ages ranged from 10 to 64 years with average of 29.7 years. Pathologic diagnoses of pseudoanaplastic variants of benign bone tumors included: osteoblastoma (4 cases), giant cell tumor (4 cases), chondromyxoid fibroma (3 cases), fibrous dysplasia (2 cases), fibrous cortical defect (1 case) and aneurysmal bone cyst (1 case). Radiography of all cases showed features of a benign bone lesion. Six cases, one case each of osteoblastoma, fibrous dysplasia, aneurysmal bone cyst, chondromyxoid fibroma, giant cell tumor and osteoblastoma, were initially misdiagnosed as osteosarcoma. The remaining cases were referred for a second opinion to rule out sarcoma. Despite the presence of significant cytologic aberrations, none of our cases showed malignant behavior following simple curettage or removal of bony lesions. Our observation justifies the concept of pseudoanaplasia in some benign bone tumors as in benign soft tissue tumors, especially in their late evolutionary stage when bizarre cytologic alterations strongly mimic a sarcoma. (orig.)

  2. Flexoelectricity in Bones.

    Science.gov (United States)

    Vasquez-Sancho, Fabian; Abdollahi, Amir; Damjanovic, Dragan; Catalan, Gustau

    2018-03-01

    Bones generate electricity under pressure, and this electromechanical behavior is thought to be essential for bone's self-repair and remodeling properties. The origin of this response is attributed to the piezoelectricity of collagen, which is the main structural protein of bones. In theory, however, any material can also generate voltages in response to strain gradients, thanks to the property known as flexoelectricity. In this work, the flexoelectricity of bone and pure bone mineral (hydroxyapatite) are measured and found to be of the same order of magnitude; the quantitative similarity suggests that hydroxyapatite flexoelectricity is the main source of bending-induced polarization in cortical bone. In addition, the measured flexoelectric coefficients are used to calculate the (flexo)electric fields generated by cracks in bone mineral. The results indicate that crack-generated flexoelectricity is theoretically large enough to induce osteocyte apoptosis and thus initiate the crack-healing process, suggesting a central role of flexoelectricity in bone repair and remodeling. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Benign bone tumors

    International Nuclear Information System (INIS)

    Gilday, D.L.; Ash, J.M.

    1976-01-01

    There is little information in the literature concerning the role of bone scanning in benign bone neoplasms except for sporadic reports. Since the advent of /sup 99m/Tc-polyphosphate, bone imaging has proven feasible and useful in locating the cause of bone pain, such as in osteoid osteomas, which are not always radiologically apparent, and in evaluating whether or not a radiologic lesion is indeed benign and solitary. Blood-pool images are particularly important in neoplastic disease, since the absence of hyperemia in the immediate postinjection period favors the diagnosis of a benign neoplasm, as does low-grade uptake on the delayed study. The scan, including pinhole magnification images, is especially valuable in diagnosing lesions in the spine and pelvis, which are poorly seen radiologically. We have studied various types of benign bone tumors, including simple and aneurysmal bone cysts, fibrous cortical defects, and nonossifying fibromas, all of which had minimal or no increased uptake of the radiopharmaceutical, unless traumatized. Although osteochondromas and enchondromas showed varied accumulation of activity, the scan was useful in differentiating these from sarcomatous lesions. All osteoid osteomas demonstrated marked activity, and could be accurately located preoperatively, as could the extent of fibrous dysplasia. The bone scan in the reticuloses also showed abnormal accumulation of activity, and aided in arriving at the prognosis and treatment of histiocytic bone lesions

  4. Caisson disease of bone.

    Science.gov (United States)

    Gregg, P J; Walder, D N

    1986-09-01

    Caisson disease of bone, which may affect compressed air workers and divers, is characterized by regions of bone and marrow necrosis that may lead to secondary osteoarthrosis of the hip and shoulder joints. A review of the pathologic, radiologic, and clinical aspects demonstrated uncertainties in the exact etiology. Early diagnosis is often not possible because of the delayed appearance of radiologic abnormalities. Research into these two aspects of this condition was carried out by the Medical Research Council Decompression Sickness Research Team in Newcastle upon Tyne over a ten-year period (1972 to 1982). Because no suitable animal model exists for the study of this condition, bone and marrow necrosis was produced by embolism of bone blood vessels with glass microspheres. With this model, it was shown that the presence of bone and marrow necrosis could be detected by bone scintigraphy using 99mTc-MDP and by measuring changes in serum ferritin concentration at a much earlier stage than was possible by radiography. However, only the former method has proved useful in clinical practice. Investigations into the etiology of caisson disease of bone have shown evidence for an increase in marrow fat cell size resulting from hyperoxia. This phenomenon may play a role in the production and localization of gas bubble emboli, which are thought to be the cause of the bone and marrow necrosis.

  5. Children's bone health

    NARCIS (Netherlands)

    I.M. van der Sluis (Inge)

    2002-01-01

    textabstractThe thesis can be divided in two main parts. In the first part (Chapter 2 to 5) bone mineral density, bone metabolism and body composition in healthy children and young adults have been evaluated, while in the second part (Chapter 6 to 10) these issues were studied in children

  6. Citoesqueleto e mecanotransdução na fisiopatologia da lesão pulmonar induzida por ventilador Cytoskeleton and mechanotransduction in the pathophysiology of ventilator-induced lung injury

    Directory of Open Access Journals (Sweden)

    Leandro Utino Taniguchi

    2010-06-01

    Full Text Available A ventilação mecânica é uma terapia importante, mas pode resultar em complicações. Uma das mais relevantes é a lesão pulmonar induzida por ventilador. Devido à hiperdistensão alveolar, o pulmão inicia um processo inflamatório, com infiltrado neutrofílico, formação de membrana hialina, fibrogênese e prejuízo de troca gasosa. Nesse processo, a mecanotransdução da hiperdistensão celular é mediada através do citoesqueleto da célula e de suas interações com a matriz extracelular e com as células vizinhas, de modo que o estímulo mecânico da ventilação se traduz em sinalização bioquímica intracelular, desencadeando ativação endotelial, permeabilidade vascular pulmonar, quimiotaxia leucocitária, produção de citocinas e, possivelmente, lesão de órgãos à distância. Estudos clínicos demonstram essa relação entre distensão pulmonar e mortalidade em pacientes com lesão pulmonar induzida por ventilador. Entretanto, apesar de o citoesqueleto ter um papel fundamental na patogênese da lesão pulmonar induzida por ventilador, a literatura carece de estudos utilizando modelos in vivo sobre as alterações do citoesqueleto e de suas proteínas associadas durante esse processo patológico.Although mechanical ventilation is an important therapy, it can result in complications. One major complication is ventilator-induced lung injury, which is caused by alveolar hyperdistension, leading to an inflammatory process, with neutrophilic infiltration, hyaline membrane formation, fibrogenesis and impaired gas exchange. In this process, cellular mechanotransduction of the overstretching stimulus is mediated by means of the cytoskeleton and its cell-cell and cell-extracellular matrix interactions, in such a way that the mechanical stimulus of ventilation is translated into an intracellular biochemical signal, inducing endothelial activation, pulmonary vascular permeability, leukocyte chemotaxis, cytokine production and, possibly

  7. Characterization of reactive flow-induced evolution of carbonate rocks using digital core analysis- part 1: Assessment of pore-scale mineral dissolution and deposition.

    Science.gov (United States)

    Qajar, Jafar; Arns, Christoph H

    2016-09-01

    The application of X-ray micro-computed tomography (μ-CT) for quantitatively characterizing reactive-flow induced pore structure evolution including local particle detachment, displacement and deposition in carbonate rocks is investigated. In the studies conducted in this field of research, the experimental procedure has involved alternating steps of imaging and ex-situ core sample alteration. Practically, it is impossible to return the sample, with micron precision, to the same position and orientation. Furthermore, successive images of a sample in pre- and post-alteration states are usually taken at different conditions such as different scales, resolutions and signal-to-noise ratios. These conditions accompanying with subresolution features in the images make voxel-by-voxel comparisons of successive images problematic. In this paper, we first address the respective challenges in voxel-wise interpretation of successive images of carbonate rocks subject to reactive flow. Reactive coreflood in two carbonate cores with different rock types are considered. For the first rock, we used the experimental and imaging results published by Qajar et al. (2013) which showed a quasi-uniform dissolution regime. A similar reactive core flood was conducted in the second rock which resulted in wormhole-like dissolution regime. We particularly examine the major image processing operations such as transformation of images to the same grey-scale, noise filtering and segmentation thresholding and propose quantitative methods to evaluate the effectiveness of these operations in voxel-wise analysis of successive images of a sample. In the second part, we generalize the methodology based on the three-phase segmentation of normalized images, microporosity assignment and 2D histogram of image intensities to estimate grey-scale changes of individual image voxels for a general case where the greyscale images are segmented into arbitrary number of phases. The results show that local (voxel

  8. Channel flow induced by wall injection of fluid and particles; Ecoulement induit par injection parietale de fluide et de particules dans un conduit

    Energy Technology Data Exchange (ETDEWEB)

    Feraille, Th.; Casalis, G. [Aerodynamics and Energetics Modeling Dept., 31 - Toulouse (France)

    2003-12-01

    The Taylor flow is the laminar single phase flow induced by gas injection through porous walls, and is assumed to represent the flow inside solid propellant motors. Such a flow is intrinsically unstable, and the generated instabilities are probably responsible for the thrust oscillations observed in the aforesaid motors. However particles are embedded in the propellants usually used, and are released in the fluid by the lateral walls during the combustion, so that there are two heterogeneous phases in the flow. The purpose of this paper is to study the influence of these particles on stability by comparison with stability results from the single phase studies, in a plane two-dimensional configuration. The particles are supposed to be chemically inert and of a uniform size. In order to carry out a linear stability study for this flow modified by the presence of particles, the mean particle velocity field is first determined, assuming that only the gas exerts forces on the particles. This field is sought in a self similar form, which imposes a limit on the size of the particles. However, the particle mass concentration cannot be obtained in a self similar form, but can only, be described by a partial differential equation. The mean flow characteristics being determined, the spectrum of the discretized linear stability operator shows first that particle addition does not trigger any new 'dangerous' modes compared with the single phase flow case. It also shows that the most amplified mode in the case of the single phase flow remains the most amplified mode in the case of the two phase flow. Moreover, the addition of particles acts continuously upon stability results, behaving linearly with respect to the particle mass concentration when the latter is small. The linear correction to the monophasic mode, as well as the evolution of the modes with weak values of the particle mass concentration at the wall, are shown to be proportional to the ejection velocity of

  9. SILICON AND BONE HEALTH

    Science.gov (United States)

    JUGDAOHSINGH, R.

    2009-01-01

    Low bone mass (osteoporosis) is a silent epidemic of the 21st century, which presently in the UK results in over 200,000 fractures annually at a cost of over one billion pounds. Figures are set to increase worldwide. Understanding the factors which affect bone metabolism is thus of primary importance in order to establish preventative measures or treatments for this condition. Nutrition is an important determinant of bone health, but the effects of the individual nutrients and minerals, other than calcium, is little understood. Accumulating evidence over the last 30 years strongly suggest that dietary silicon is beneficial to bone and connective tissue health and we recently reported strong positive associations between dietary Si intake and bone mineral density in US and UK cohorts. The exact biological role(s) of silicon in bone health is still not clear, although a number of possible mechanisms have been suggested, including the synthesis of collagen and/or its stabilization, and matrix mineralization. This review gives an overview of this naturally occurring dietary element, its metabolism and the evidence of its potential role in bone health. PMID:17435952

  10. Aneurysmal bone cysts

    Directory of Open Access Journals (Sweden)

    Rangachari P

    2005-01-01

    Full Text Available Back ground: Aneurysmal bone cysts have raised intra-cystic pressures which are dynamic and diagnostic in nature. Aneurysmal bone cysts could be diagnosed from other benign cystic lesions of bone by recording their intra-cystic pressures with a spinal manometer. Raised intra-cystic pressures in aneurysmal bone cysts are maintained as long as the periosteum over the cyst is intact even in those with pathological fractures. Even though its pathology is definite its aetio-pathology is not clear Method: Fourteen out of 16 radiologically benign cystic lesions of bone were subjected to intra-cystic pressure recordings with spinal manometer. Other two cysts had displaced unimpacted pathological fractures and so their intra-cystic pressures could not be recorded. All 16 cysts were subjected to histo-pathological examination to confirm their diagnosis and to find out for any pre-existing benign pathology. All the cysts were surgically treated. Results: Fourteen benign cystic lesions of bone were diagnosed as aneurysmal bone cysts preoperatively by recording raised intra-cystic pressures and confirmed by histo-pathology. In addition, histo-pathology revealed pre-existing benign pathology. All cysts were successfully treated surgically. Conclusions: Since, there is appreciable rise in intra-cystic dynamic pressures, the aneurysmal bone cyst is considered to be due to either sudden venous obstruction or arterio-venous shunt. Pre-operative intra-cystic pressure recordings help not only to diagnose aneurysmal bone cysts but also to assess the quantum of blood loss and its replacement during surgery.

  11. Autogenous tooth bone graft: Ingenious bone regeneration material

    Directory of Open Access Journals (Sweden)

    Chadalavada Sarala

    2018-01-01

    Full Text Available Tooth-derived bone graft material, which is proved to be rich in bone growth factors and bone morphogenic proteins (BMPs, have been becoming a practical substitute to bone grafting. It can also be used as a carrier for growth factors and stem cells as reported in many recent studies. Autogenous-tooth bone grafting technique is significant as this biomaterial has excellent bone regeneration capacity and also relatively non-existent chances of antigenicity, genetic diseases and disease transmission. In this article, a broad overview of the published findings with regard to the properties and uses of tooth-derived regenerative bone grafting is discussed.

  12. Bone changes in endometrosis

    International Nuclear Information System (INIS)

    Jensen, P.S.; Orphanoudakis, S.C.; Hutchinson-Williams, K.; Lewis, A.B.; Lovett, L.; Polan, M.L.; DeCherney, A.H.; Comite, F.

    1989-01-01

    In this study, quantitative CT is used to measure bone in the distal radius in normal women, women with endometriosis who had not been treated, and women with endometriosis who had been treated with danazol--an anabolic (androgen) steroid. Measurements of cortex and trabeculae indicate that untreated women have decreased bone mass (1125 HU and 160 HU, respectively), compared with bone mass in normal women (1269 HU and 257 HU; P < .05) and treated women (1238 HU and 255 HU). This finding is important because the most effective way to reduce the complications of osteoporosis is identification of risk factors, prevention, and early treatment

  13. Bone scintigraphy for horses

    International Nuclear Information System (INIS)

    Jahn, Werner

    2010-01-01

    Scintigraphy (bone scan) is being used approximately since 1980 in the horse under general anaesthesia. With the construction of custom-made overhead gantries for gamma-cameras scintigraphy found widespread entry in big equine referral hospitals for bone-scanning of the standing horse. Indications for the use of a bone scan in the horse are inflammatory alterations in the locomotor apparatus. It is primarily used for diagnosis of lameness of unknown origin, suspect of stress fracture or hairline fracture and for horses with bad riding comfort with suspected painful lesions in the spine. (orig.)

  14. Periodontal bone lesions

    International Nuclear Information System (INIS)

    Linden, L.W.J. van der.

    1985-01-01

    In the course of life the periodontum is subject to changes which may be physiological or pathological. Intraoral radiographs give insight into the hard structures of the dentomaxillar region and provides information on lesions in the bone of the periodontum in that they show radiopacities and radiolucencies caused by such lesions. In this thesis the relation is investigated between the true shape and dimensions of periodontal bone lesions and their radiographic images. A method is developed and tested of making standardized and reproducible radiographs suitable for longitudinal studies of periodontal lesions. Also the possibility is demonstrated of an objective and reproducible interpretation of radiographic characteristics of periodontal bone lesions. (Auth.)

  15. Lutein Enhances Bone Mass by Stimulating Bone Formation and Suppressing Bone Resorption in Growing Mice.

    Science.gov (United States)

    Takeda, Hiroshi; Tominari, Tsukasa; Hirata, Michiko; Watanabe, Kenta; Matsumoto, Chiho; Grundler, Florian M W; Inada, Masaki; Miyaura, Chisato

    2017-01-01

    Lutein is a member of the xanthophyll family of carotenoids, which are known to prevent hypoxia-induced cell damage in the eye by removing free radicals. However, its role in other tissues is controversial, and the effects of lutein on bone tissues are unknown. To identify a possible role of lutein in bone tissues, we examined the effects of lutein on bone formation and bone resorption and on femoral bone mass in mice. Lutein enhanced the formation of mineralized bone nodules in cultures of osteoblasts. On the other hand, lutein clearly suppressed 1α, 25-dihydroxyvitamin D 3 -induced bone resorption as measured by pit formation in organ culture of mouse calvaria. In co-cultures of bone marrow cells and osteoblasts, lutein suppressed 1α, 25-dihydroxyvitamin D 3 -induced osteoclast formation. In cultures of bone marrow macrophages, lutein suppressed soluble RANKL, the receptor activator of nuclear factor-kappaB (NF-κB) ligand, induced osteoclast formation. When five-week-old male mice were orally administered lutein for 4 weeks, the femoral bone mass was clearly enhanced in cortical bone, as measured by bone mineral density in dual X-ray absorptiometry and micro computed tomography (µCT) analyses. The present study indicates that lutein enhances bone mass in growing mice by suppressing bone resorption and stimulating bone formation. Lutein may be a natural agent that promotes bone turnover and may be beneficial for bone health in humans.

  16. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  17. Bone X-Ray (Radiography)

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  18. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small dose ... limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is ...

  19. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive ...

  20. Bone Graft Alternatives

    Science.gov (United States)

    ... spinal deformity, or who have some types of disc herniations. In certain types of spinal fusion, bone grafts ... Specialist SEARCH Download Brochure ENGLISH Related Treatments Cervical Disc Herniation Fusion Lumbar Disc Herniation {1} ##LOC[OK]## {1} ## ...

  1. BONE MARROW TRANSPLANTATION

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. BONE MARROW TRANSPLANTATION. AUTOLOGOUS TRANSPLANTS: Oct 1986 - Dec 2007. Multiple Myeloma 90. NHL 39. Hodgkins lymphoma 19. AML 36. APML 9. ALL 2. Amyloidosis 2. Granulocytic Sarcoma 1.

  2. Bone marrow transplant - discharge

    Science.gov (United States)

    ... lymphoblastic leukemia (ALL) Acute myeloid leukemia - adult Aplastic anemia Bone marrow transplant Chronic lymphocytic leukemia (CLL) Chronic myelogenous leukemia (CML) Graft-versus-host disease Hodgkin lymphoma Multiple myeloma Non-Hodgkin lymphoma Patient ...

  3. Bone marrow biopsy

    Science.gov (United States)

    ... test is used to diagnose leukemia, infections, some types of anemia, and other blood disorders. It may also be ... the bone marrow contains the proper number and types of blood-forming (hematopoietic) cells, fat cells, and connective tissues.

  4. Nanocomposites for bone tissue regeneration.

    Science.gov (United States)

    Sahoo, Nanda Gopal; Pan, Yong Zheng; Li, Lin; He, Chao Bin

    2013-04-01

    Natural bone tissue possesses a nanocomposite structure that provides appropriate physical and biological properties. For bone tissue regeneration, it is crucial for the biomaterial to mimic living bone tissue. Since no single type of material is able to mimic the composition, structure and properties of native bone, nanocomposites are the best choice for bone tissue regeneration as they can provide the appropriate matrix environment, integrate desirable biological properties, and provide controlled, sequential delivery of multiple growth factors for the different stages of bone tissue regeneration. This article reviews the composition, structure and properties of advanced nanocomposites for bone tissue regeneration. It covers aspects of interest such as the biomimetic synthesis of bone-like nanocomposites, guided bone regeneration from inert biomaterials and bioactive nanocomposites, and nanocomposite scaffolds for bone tissue regeneration. The design, fabrication, and in vitro and in vivo characterization of such nanocomposites are reviewed.

  5. Uranium in fossil bones

    International Nuclear Information System (INIS)

    Koul, S.L.

    1978-01-01

    An attempt has been made to determine the uranium content and thus the age of certain fossil bones Haritalyangarh (Himachal Pradesh), India. The results indicate that bones rich in apatite are also rich in uranium, and that the radioactivity is due to radionuclides in the uranium series. The larger animals apparently have a higher concentration of uranium than the small. The dating of a fossil jaw (elephant) places it in the Pleistocene. (Auth.)

  6. Engineered vascularized bone grafts

    OpenAIRE

    Tsigkou, Olga; Pomerantseva, Irina; Spencer, Joel A.; Redondo, Patricia A.; Hart, Alison R.; O’Doherty, Elisabeth; Lin, Yunfeng; Friedrich, Claudia C.; Daheron, Laurence; Lin, Charles P.; Sundback, Cathryn A.; Vacanti, Joseph P.; Neville, Craig

    2010-01-01

    Clinical protocols utilize bone marrow to seed synthetic and decellularized allogeneic bone grafts for enhancement of scaffold remodeling and fusion. Marrow-derived cytokines induce host neovascularization at the graft surface, but hypoxic conditions cause cell death at the core. Addition of cellular components that generate an extensive primitive plexus-like vascular network that would perfuse the entire scaffold upon anastomosis could potentially yield significantly higher-quality grafts. W...

  7. Bone changes in phenylketonuria

    International Nuclear Information System (INIS)

    Hong, Hyun Sook; Lee, Hae Kyung; Kwon, Kui Hyang; Choi, Deuk Lin; Lee, Dong Hwan

    1998-01-01

    While treating 14 phenylketonurial (PKU) patients, we evaluated bone density, changes in bone age, and bony changes such as spiculation or metaphyseal widening. A total of 14 PKU patients aged between 1 month and 14 years (mean, 6.4 years) were under dietary treatment. Eight and eleven patients underwent radiography of the left hand and wrist and bone densitometry (BMD) of the lumbar spine, respectively. The results were reviewed with regard to abnormal bony changes, delayed bone age, and osteopenia. Patients were assigned to either the early or late treatment group, depending on whether or not dietary therapy was started before 3 months of age. Those in whom a blood phenylalanine level of under 10 mg/dl was maintained were assigned to the good control group; others were classified as variable control. The findings of radiographs of the left hand and lumbar BMD were evaluated in relation to the time of dietary therapy, and adequacy of treatment. None of the 14 PKU patients who underwent dietary therapy had bony abnormalities such as spiculation or metaphyseal widening. In four of the 11, bone age was at least one year less than chronological age, and on lumbar BMD, osteoporosis was seen. For the evaluation of bone change in PKU patients, plain radiography and BMD are thus complementary. (author). 18 refs., 1 tab., 2 figs

  8. Bone changes in phenylketonuria

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Hyun Sook; Lee, Hae Kyung; Kwon, Kui Hyang; Choi, Deuk Lin; Lee, Dong Hwan [Soonchunhyang Univ., Seoul (Korea, Republic of). Hospital

    1998-02-01

    While treating 14 phenylketonurial (PKU) patients, we evaluated bone density, changes in bone age, and bony changes such as spiculation or metaphyseal widening. A total of 14 PKU patients aged between 1 month and 14 years (mean, 6.4 years) were under dietary treatment. Eight and eleven patients underwent radiography of the left hand and wrist and bone densitometry (BMD) of the lumbar spine, respectively. The results were reviewed with regard to abnormal bony changes, delayed bone age, and osteopenia. Patients were assigned to either the early or late treatment group, depending on whether or not dietary therapy was started before 3 months of age. Those in whom a blood phenylalanine level of under 10 mg/dl was maintained were assigned to the good control group; others were classified as variable control. The findings of radiographs of the left hand and lumbar BMD were evaluated in relation to the time of dietary therapy, and adequacy of treatment. None of the 14 PKU patients who underwent dietary therapy had bony abnormalities such as spiculation or metaphyseal widening. In four of the 11, bone age was at least one year less than chronological age, and on lumbar BMD, osteoporosis was seen. For the evaluation of bone change in PKU patients, plain radiography and BMD are thus complementary. (author). 18 refs., 1 tab., 2 figs.

  9. Bone nutrients for vegetarians.

    Science.gov (United States)

    Mangels, Ann Reed

    2014-07-01

    The process of bone mineralization and resorption is complex and is affected by numerous factors, including dietary constituents. Although some dietary factors involved in bone health, such as calcium and vitamin D, are typically associated with dairy products, plant-based sources of these nutrients also supply other key nutrients involved in bone maintenance. Some research suggests that vegetarian diets, especially vegan diets, are associated with lower bone mineral density (BMD), but this does not appear to be clinically significant. Vegan diets are not associated with an increased fracture risk if calcium intake is adequate. Dietary factors in plant-based diets that support the development and maintenance of bone mass include calcium, vitamin D, protein, potassium, and soy isoflavones. Other factors present in plant-based diets such as oxalic acid and phytic acid can potentially interfere with absorption and retention of calcium and thereby have a negative effect on BMD. Impaired vitamin B-12 status also negatively affects BMD. The role of protein in calcium balance is multifaceted. Overall, calcium and protein intakes in accord with Dietary Reference Intakes are recommended for vegetarians, including vegans. Fortified foods are often helpful in meeting recommendations for calcium and vitamin D. Plant-based diets can provide adequate amounts of key nutrients for bone health. © 2014 American Society for Nutrition.

  10. Bone mineral density and elemental composition of bone tissues in "red-boned" Guishan goats.

    Science.gov (United States)

    Wu, Chenchen; Wang, Jianguo; Li, Peng; Liu, Guowen; Li, Xiaobing; Ma, Huarong; Wang, Weizhong; Wang, Zhe; Ge, Changrong; Gao, Shizheng

    2012-12-01

    Red-colored bones were first found in Guishan goats in the 1980s, and they were subsequently designated red-boned Guishan goats. However, the difference remains unclear between the bone mineral density (BMD) or elemental composition in bones between red-boned Guishan goats and common Guishan goats. Analysis of femoral bone samples by dual-energy X-ray absorptiometry and inductively coupled plasma optical emission spectrometry revealed an increase in bone mineral density in the femoral diaphysis and distal femur of red-boned Guishan goats at 18 and 36 months of age. The data revealed that BMD increased in both the red-boned and common Guishan goats from 18 to 36 months of age. The data also indicated that the ratio of the BMD values of red-boned to common Guishan goats was higher at 36 months of age than they were at 18 months of age. Furthermore, the levels of calcium, phosphorus, magnesium, barium, zinc, manganese, and aluminum were significantly higher in red-boned Guishan goats than common Guishan goats at 18 and 36 months of age. The results indicate that the red-boned Guishan goats were linked to the elevated levels of mineral salts observed in the bones and that this in turn may be linked to the elevated BMD levels encountered in red-boned Guishan goats. These reasons may be responsible for the red coloration in the bones of red-boned Guishan goats.

  11. Guided bone regeneration : the influence of barrier membranes on bone grafts and bone defects

    NARCIS (Netherlands)

    Gielkens, Pepijn Frans Marie

    2008-01-01

    Guided bone regeneration (GBR) can be described as the use of a barrier membrane to provide a space available for new bone formation in a bony defect. The barrier membrane protects the defect from in-growth of soft tissue cells and allows bone progenitor cells to develop bone within a blood clot

  12. Chimeric Self-assembling Nanofiber Containing Bone Marrow Homing Peptide's Motif Induces Motor Neuron Recovery in Animal Model of Chronic Spinal Cord Injury; an In Vitro and In Vivo Investigation.

    Science.gov (United States)

    Tavakol, Shima; Saber, Reza; Hoveizi, Elham; Aligholi, Hadi; Ai, Jafar; Rezayat, Seyed Mahdi

    2016-07-01

    To date, spinal cord injury (SCI) has remained an incurable disaster. The use of self-assembling peptide nanofiber containing bioactive motifs such as bone marrow homing peptide (BMHP1) as an injectable scaffold in spinal cord regeneration has been suggested. Human endometrial-derived stromal cells (hEnSCs) have been approved by the FDA for clinical application. In this regard, we were interested in investigating the role of BMHP1 in hEnSCs' neural differentiation in vitro and evaluating the supportive effects of this scaffold in rat model of chronic SCI. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH), lactate dehydrogenase (LDH) release, 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay, real-time PCR, and immunocyotochemistry (ICC) were performed as a biocompatibility and neural differentiation evaluations on neuron-like hEnSC-derived cells encapsulated into nanofiber. Nanofiber was implanted into rats and followed by behavioral test, Nissl, luxol fast blue (LFB) staining and immunohistostaining (IHC). Results indicated that cell membrane of neuroblastoma cells were more sensitive than hEnSCs to concentration of proton and cell proliferation decreased with increase of concentration. This effect might be related to oxygen tension and elastic modules of scaffold. -BMHP1 nanofiber induced neural differentiation in hEnSC and decreased GFAP gene and protein as a marker of reactive astrocytes in vitro and in vivo. A reason for this finding might be related to the role of spacer number in induction of mechano-transduction signals. The presented study revealed the chimeric BMHP1 nanofiber induced higher axon regeneration and myelniation around the cavity and motor neuron function was encouraged to improve with less inflammatory response following SCI in rats. These effects were possibly due to nanostructured topography and mechano-transduction signals derived from hydrogel at low concentration.

  13. Formation of D- and I-shaped geochemical profiles in saucer-shaped sills due to post- emplacement magma flow induced by thermal stresses

    Science.gov (United States)

    Aarnes, I.; Podladchikov, Y. Y.; Neumann, E.

    2007-12-01

    elements due to the outflux through a stationary crystal network, resulting in a less evolved total system composition from a total lower melt percentage. Dimensional analysis combined with a numerical model developed using finite element method is used to constrain the post-emplacement melt flow induced by cooling. The numerical model show that large underpressure-anomalies (in the order of -1e8 Pa) develop at the cooling margins. The melt flow following Darcy's law of porous flow is integrated over time into total melt displacement. The two main parameters controlling the magnitude of the melt displacement are permeability of the crystal network and viscosity of the melt. By using a basaltic viscosity and the permeability of 90% crystallinity we get a total melt displacement that is larger than 10% of the sill thickness. We therefore conclude that the post-emplacement flow as a differentiation mechanism causing D-shaped profiles is feasible under natural occurring conditions. I-shaped profiles is predicted to occur where there is no or limited flow due to e.g. rapid cooling (i.e. rapidly decreasing permeability and increasing viscosity) or in melts with high silica contents and thus higher viscosity. This model can be applied to any magmatic sheet-intrusion, regardless of orientation.

  14. Morphogens, Membranes and Mechanotransduction in Articular Cartilage

    Science.gov (United States)

    Motaung, Shirley; Chan, Stephanie; Reddi, A. Hari

    The three fundamentals of developmental biology are cell growth, cellular differentiation, and morphogenesis. Morphogenesis is the process of the generation of the shape of tissues, organs, and entire organisms from various cells. During embryonic development, as cells reproduce and divide, chemical and mechanical signals induce the cell to sort and differentiate into specialized cells. Morphogenesis is the process by which these cells become distributed and organized into tissues and organs. Morphogenetic responses can be stimulated in organisms by morphogenetic proteins, hormones, and environmental cues. There are different types of molecules that play an important role during morphogenesis and include the transcription factors and morphogens themselves.

  15. Mechanotransduction through the plasma membrane & cytoskeleton

    Science.gov (United States)

    Haase, Kristina; Pelling, Andrew

    2012-02-01

    Mechanical forces initiate immediate and long-term changes in cells; however the exact mechanisms remain unclear, albeit crucial for understanding the pathology of disease. We used combined confocal and atomic force microscopy (AFM) to investigate changes in cell morphology and elasticity in response to a mechanical stimulus. The AFM was used as a nano-indentor to gauge the response of the membrane and cytoskeleton (CSK) of HeLa cells. We observed their viscoelastic nature by probing cells transfected with a green fluorescent protein localized at the plasma membrane. Inhibition of acto-myosin contractility (AMc) resulted in a significant decrease of cellular elasticity, and a corresponding increase in mean deformation. We also investigated the rate at which the membrane and CSK deform and relax in response to a local force. The response to a local perturbation is nearly instantaneous for control cells and shows no statistical difference when compared to cells treated with CSK-inhibiting drugs. Inhibition of AMc affects the rate of recovery, in comparison to control cells which recover quite quickly (30-60s). Overall, we demonstrated short and long-term deformation and subsequent recovery of both the cell membrane and actin network in response to a local force.

  16. Modulation of oligodendrocyte differentiation by mechanotransduction

    Directory of Open Access Journals (Sweden)

    Tânia Lourenço

    2016-11-01

    Full Text Available Oligodendrocytes (OLs are responsible for the myelination of axons in the central nervous system. The differentiation of OLs encompasses several stages, through which cells undergo dramatic biochemical and morphological changes. Oligodendrocyte differentiation is modulated by soluble factors (SFs — such as growth factors and hormones —, known to be essential for each maturation stage. Besides SFs, insoluble factors such as extracellular matrix (ECM proteins and other microenvironmental elements also play a pivotal role during OL differentiation. Recently, a growing number of studies were published concerning the effect of biophysical properties of the extracellular milieu on oligodendrocyte differentiation and myelination, showing the importance of ECM stiffness and topography, strain forces and spatial constraints. For instance, it was shown in vitro that OL differentiation and maturation is enhanced by substrates within the reported range of stiffness of the brain and that this effect is potentiated by the presence of merosin, whereas the myelination process is influenced by the diameter of axonal-like fibers. In this mini review, we will discuss the effect of mechanical cues during oligodendrocyte differentiation and the possible molecular mechanisms involved in such regulation.

  17. Porous surface modified bioactive bone cement for enhanced bone bonding.

    Directory of Open Access Journals (Sweden)

    Qiang He

    Full Text Available Polymethylmethacrylate bone cement cannot provide an adhesive chemical bonding to form a stable cement-bone interface. Bioactive bone cements show bone bonding ability, but their clinical application is limited because bone resorption is observed after implantation. Porous polymethylmethacrylate can be achieved with the addition of carboxymethylcellulose, alginate and gelatin microparticles to promote bone ingrowth, but the mechanical properties are too low to be used in orthopedic applications. Bone ingrowth into cement could decrease the possibility of bone resorption and promote the formation of a stable interface. However, scarce literature is reported on bioactive bone cements that allow bone ingrowth. In this paper, we reported a porous surface modified bioactive bone cement with desired mechanical properties, which could allow for bone ingrowth.The porous surface modified bioactive bone cement was evaluated to determine its handling characteristics, mechanical properties and behavior in a simulated body fluid. The in vitro cellular responses of the samples were also investigated in terms of cell attachment, proliferation, and osteoblastic differentiation. Furthermore, bone ingrowth was examined in a rabbit femoral condyle defect model by using micro-CT imaging and histological analysis. The strength of the implant-bone interface was also investigated by push-out tests.The modified bone cement with a low content of bioactive fillers resulted in proper handling characteristics and adequate mechanical properties, but slightly affected its bioactivity. Moreover, the degree of attachment, proliferation and osteogenic differentiation of preosteoblast cells was also increased. The results of the push-out test revealed that higher interfacial bonding strength was achieved with the modified bone cement because of the formation of the apatite layer and the osseointegration after implantation in the bony defect.Our findings suggested a new bioactive

  18. Horizontal bone augmentation by means of guided bone regeneration.

    Science.gov (United States)

    Benic, Goran I; Hämmerle, Christoph H F

    2014-10-01

    The development of bone augmentation procedures has allowed placement of dental implants into jaw bone areas lacking an amount of bone sufficient for standard implant placement. Thus, the indications for implants have broadened to include jaw regions with bone defects and those with a bone anatomy that is unfavorable for implant anchorage. Of the different techniques, the best documented and the most widely used method to augment bone in localized alveolar defects is guided bone regeneration. A large body of evidence has demonstrated the successful use of guided bone regeneration to regenerate missing bone at implant sites with insufficient bone volume and the long-term success of implants placed simultaneously with, or after, guided bone regeneration. However, the influence of guided bone regeneration on implant survival and success rates, and the long-term stability of the augmented bone, remain unknown. Many of the materials and techniques currently available for bone regeneration of alveolar ridge defects were developed many years ago. Recently, various new materials and techniques have been introduced. Many of them have, however, not been sufficiently documented in clinical studies. The aim of this review was to present the scientific basis of guided bone regeneration and the accepted clinical procedures. A classification of bone defects has been presented, aiming at simplifying the decision-making process regarding the choice of strategy for bone augmentation. Finally, an outlook into actual research and the possible future options related to bone augmentation has been provided. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Gene Expression in Bone

    Science.gov (United States)

    D'Ambrogio, A.

    Skeletal system has two main functions, to provide mechanical integrity for both locomotion and protection and to play an important role in mineral homeostasis. There is extensive evidence showing loss of bone mass during long-term Space-Flights. The loss is due to a break in the equilibrium between the activity of osteoblasts (the cells that forms bone) and the activity of osteoclasts (the cells that resorbs bone). Surprisingly, there is scanty information about the possible altered gene expression occurring in cells that form bone in microgravity.(Just 69 articles result from a "gene expression in microgravity" MedLine query.) Gene-chip or microarray technology allows to screen thousands of genes at the same time: the use of this technology on samples coming from cells exposed to microgravity could provide us with many important informations. For example, the identification of the molecules or structures which are the first sensors of the mechanical stress derived from lack of gravity, could help in understanding which is the first event leading to bone loss due to long-term exposure to microgravity. Consequently, this structure could become a target for a custom-designed drug. It is evident that bone mass loss, observed during long-time stay in Space, represents an accelerated model of what happens in aging osteoporosis. Therefore, the discovery and design of drugs able to interfere with the bone-loss process, could help also in preventing negative physiological processes normally observed on Earth. Considering the aims stated above, my research is designed to:

  20. Temporal bone meningiomas.

    Science.gov (United States)

    Vrionis, F D; Robertson, J H; Gardner, G; Heilman, C B

    1999-01-01

    Meningiomas involving the temporal bone may originate from arachnoid cell nests present within the temporal bone (intratemporal), but more frequently originate from arachnoid cell nests of the posterior or middle cranial fossa with secondary invasion of the TB (extratemporal). In this study, we retrospectively reviewed the charts of 13 patients with meningiomas involving the temporal bone who underwent surgery. Tumors of the posterior fossa with only temporal bone hyperostosis, but without invasion, were excluded. Patients presented primarily with otologic symptoms and signs. The tumors originated in the temporal bone (5/13), jugular foramen (4/13), petroclival region (2/13), the asterion (1/13) or the internal auditory meatus (1/13). All of the intratemporal meningiomas had the radiological appearance of en-plaque menigiomas. The tumor extended into the middle ear (11/13), eustachian tube (5/13), and/or the labyrinth (3/13). A gross total resection was achieved in 11 patients and a subtotal resection in 2 patients. The lower cranial nerves were infiltrated by tumor in 4 patients, and were sacrificed. At a mean follow-up of approximately 6 years, 12 patients are currently alive and doing well and 1 died from tumor progression. Six patients showed tumor recurrence and were reoperated on (5/6) or followed conservatively (1/6). Surgical treatment of temporal bone meningiomas is associated with high recurrence rate due to indiscreet tumor margins. Combined surgical approaches (temporal craniotomy and mastoidectomy) by neurosurgical and otological teams are recommended for meningiomas originating in the temporal bone.

  1. Bone anabolic versus bone anticatabolic treatment of postmenopausal osteoporosis.

    Science.gov (United States)

    Lyritis, George P; Georgoulas, Thomas; Zafeiris, Christos P

    2010-09-01

    Increased bone fragility after menopause is commonly associated with accelerated bone loss and aggressive osteoclastic function. This is attributed to increased RANKL production and impaired osteoprotegerin synthesis. Fast bone loss leads to trabecular perforations, dramatic diminution of bone strength, and unexpected fractures. To avoid osteoporotic fractures, elimination of fast bone loss is recommended. Antiosteoclastic drugs, apart from estrogens, are the selective estrogen receptor modulators, calcitonins, and amino-bisphosphonates. These drugs increase bone mass by 1-5%, but reduce the relative risk of a vertebral fracture by 30-70%. Long-term exposure to bisphosphonates may be related to low bone turnover. In elderly and severe osteoporosis, antiosteoclastic regimens hardly correct the depressed osteoblastic function. Intermittent teriperatide stimulates osteoblastic function, improves bone geometry, and has an additional analgesic effect. While both anticatabolic and anabolic agents increase bone mass and decrease the risk of spinal fractures and occasionally of the fracture of the femoral neck, there are differences in the mode of their action. These pathophysiological differences are tentative therapeutic tools for the prevention of osteoporotic fractures. A fast bone loss, associated with increased biochemical markers, is the main indicator for anticatabolic agents, while impaired bone geometry, normal or low bone markers, and established bone architectural changes are in favor of the anabolic agents. Strontium ranelate combines the anticatabolic effect with an additional anabolic action. © 2010 New York Academy of Sciences.

  2. Microarchitecture of irradiated bone: comparison with healthy bone

    Science.gov (United States)

    Bléry, Pauline; Amouriq, Yves; Guédon, Jeanpierre; Pilet, Paul; Normand, Nicolas; Durand, Nicolas; Espitalier, Florent; Arlicot, Aurore; Malard, Olivier; Weiss, Pierre

    2012-03-01

    The squamous cell carcinomas of the upper aero-digestive tract represent about ten percent of cancers. External radiation therapy leads to esthetic and functional consequences, and to a decrease of the bone mechanical abilities. For these patients, the oral prosthetic rehabilitation, including possibilities of dental implant placement, is difficult. The effects of radiotherapy on bone microarchitecture parameters are not well known. Thus, the purpose of this study is to assess the effects of external radiation on bone micro architecture in an experimental model of 25 rats using micro CT. 15 rats were irradiated on the hind limbs by a single dose of 20 Grays, and 10 rats were non irradiated. Images of irradiated and healthy bone were compared. Bone microarchitecture parameters (including trabecular thickness, trabecular number, trabecular separation, connectivity density and tissue and bone volume) between irradiated and non-irradiated bones were calculated and compared using a Mann and Whitney test. After 7 and 12 weeks, images of irradiated and healthy bone are different. Differences on the irradiated and the healthy bone populations exhibit a statistical significance. Trabecular number, connectivity density and closed porosity are less important on irradiated bone. Trabecular thickness and separation increase for irradiated bone. These parameters indicate a decrease of irradiated bone properties. Finally, the external irradiation induces changes on the bone micro architecture. This knowledge is of prime importance for better oral prosthetic rehabilitation, including implant placement.

  3. Calcar bone graft

    Energy Technology Data Exchange (ETDEWEB)

    Bargar, W.L.; Paul, H.A.; Merritt, K.; Sharkey, N.

    1986-01-01

    A canine model was developed to investigate the use of an autogeneic iliac bone graft to treat the calcar deficiency commonly found at the time of revision surgery for femoral component loosening. Five large male mixed-breed dogs had bilateral total hip arthroplasty staged at three-month intervals, and were sacrificed at six months. Prior to cementing the femoral component, an experimental calcar defect was made, and a bicortical iliac bone graft was fashioned to fill the defect. Serial roentgenograms showed the grafts had united with no resorption. Technetium-99 bone scans showed more uptake at three months than at six months in the graft region. Disulfine blue injection indicated all grafts were perfused at both three and six months. Thin section histology, fluorochromes, and microradiographs confirmed graft viability in all dogs. Semiquantitative grading of the fluorochromes indicated new bone deposition in 20%-50% of each graft at three months and 50%-80% at six months. Although the calcar bone graft was uniformly successful in this canine study, the clinical application of this technique should be evaluated by long-term results in humans.

  4. Fibrosarcoma of bone

    International Nuclear Information System (INIS)

    Taconis, W.K.

    1982-01-01

    A general clinical-radiological description of fibrosarcoma of bone, including tumours with features of malignant fibrous histiocytoma is presented. 104 patients with fibrosarcoma of the long bones are analysed in terms of age and sex distribution, symptoms, duration of symptoms and tumour localization. The radiological findings obtained in patients with fibrosarcoma of the long bones are discussed. The treatment and course of fibrosarcoma of the long bones are discussed. Data on the type of therapy given were available on 103 patients: 67 were treated by ablative surgery either immediately or within three months of preceding local surgery and/or radiotherapy. In the remaining 36 cases treatment consisted of local surgery, radiotherapy or a combination of these, or non-curative (palliative) treatment. In a few cases ablative surgery was performed at a later stage. 13 patients with fibrosarcoma of the axial skeleton and 14 with fibrosarcoma of the jaws are considered. A causistic discussion of patients with a secondary fibrosarcoma is presented. Secondary fibrosarcoma was found in a total of 19 patients (14%); 4 after irradiation. The features of significance for the course of the disease are discussed: general features such as age and sex, tumour localization in the long bones, presence or absence of a pathological fracture, and the radiological and histological characteristics of the tumour. The type of therapy and the occurrence of lung metastases in relation to the course of the disease is also discussed. (Auth.)

  5. [Bone Cell Biology Assessed by Microscopic Approach. Bone histomorphometry of remodeling, modeling and minimodeling].

    Science.gov (United States)

    Yamamoto, Noriaki; Shimakura, Taketoshi; Takahashi, Hideaki

    2015-10-01

    Bone histomorphometry is defined as a quantitative evaluation of bone remodeling. In bone remodeling, bone resorption and bone formation are coupled with scalloped cement lines. Another mechanism of bone formation is minimodeling which bone formation and resorption are independent. The finding of minimodeling appeared in special condition with metabolic bone disease or anabolic agents. We need further study for minimodeling feature and mechanism.

  6. Is More Cortical Bone Decortication Effective on Guided Bone Augmentation?

    Science.gov (United States)

    Acar, Ahmet Hüseyin; Alan, Hilal; Özgür, Cem; Vardi, Nigar; Asutay, Fatih; Güler, Çiğdem

    2016-10-01

    This study aims to evaluate the possible effect of more cortical bone decortication (CBD) on guided bone augmentation. A total of 16 New Zealand rabbits and 32 titanium domes were used. No cortical bone decortication was applied to the control group and in the study groups, the cortical bones were decorticated with a round burr (Group A: 1 hole with bleeding, Group B: 5 holes with bleeding, Group C: a thin layer of compact bone was completely removed with no bleeding). Then 2 titanium domes were placed on the calvarium of each rabbit with hydroxyapatite/beta-tricalcium phosphate. After 3 months, the animals were sacrificed and specimens were sent for histological and histomorphometric analysis. Histological and histomorphometric analysis showed that bone decortication with burr significantly increased new bone regeneration in all the experimental groups compared with the control group (P guided bone augmentation. However, a greater amount of CBD does not have a greater effect.

  7. Percutaneous bone tumor management.

    Science.gov (United States)

    Gangi, Afshin; Buy, Xavier

    2010-06-01

    Interventional radiology plays a major role in the management of bone tumors. Many different percutaneous techniques are available. Some aim to treat pain and consolidate a pathological bone (cementoplasty); others aim to ablate tumor or reduce its volume (sclerotherapy, thermal ablation). In this article, image-guided techniques of primary and secondary bone tumors with vertebroplasty, ethanol injection, radiofrequency ablation, laser photocoagulation, cryoablation, and radiofrequency ionization (coblation) will be reviewed. For each modality, the principles, the indications, and the results will be presented. The technical choice depends on the therapeutic intent-curative or palliative-and the need for consolidation, but also on the general status of the patient and the other therapeutic options. For the most complex cases, combined treatments can be required. However, the less disabling technique should always be considered first.

  8. Bone pathology inpsoriatic arthritis

    Directory of Open Access Journals (Sweden)

    V. V. Badokin

    2007-01-01

    Full Text Available Objective. To study different variants of osteolysis in pts with psoriatic arthritis (PA and to reveal their relationship with other clinico-radiological features of joint damage. Material and methods. 370 pts with definite PA having different variants of joint damage were included. Radiological examination of bones and joints (in some cases large picture frame was performed. Morphological evaluation of synovial biopsies was done in 34 pts with PA and 10 pts with rheumatoid arthritis (RA. Results. Different types of osteolysis were revealed in 80 (21,6% pts. Osteolytic variant of joint damage was present in 29 pts. 33 pts had acral, 48 — intra-articular osteolysis and 16 - true bone atrophy. Frequency and intensity of bone resorption were associated with severity of PA. Acral osteolysis correlated with arthritis of distal interphalangeal joints and onychodystrophy. Intra-articular osteolysis was most often present in distal interphalangeal joints of hands and metacarpophalangeal joints (39,6% and 41,7% respectively. Characteristic feature of PA was combination of prominent resorption with formation of bone ankylosis and periosteal reaction. Ankylosis was present in 33,3% of pts with intra-articular osteolysis and in 60% of pts with combination of different osteolysis variants. Systemic reaction of microcirculation in synovial biopsies was most prominent in osteolytic variant: marked thickening of capillary and venule basal membrane with high level of acid phosphatase, increased capillary and precapillary blood flow with stasis features, vascular lymphocyte and macrophage infiltration, productive vasculitis with annular wall thickening, thrombovasculitis and villi deep layer sclerosis. Conclusion. Different variants of osteolysis show bone involvement in PA. Acral and intra- articular osteolysis association with bone ankylosis and periostitis proves their common pathogenetic entity.

  9. Biochemical markers of bone turnover

    International Nuclear Information System (INIS)

    Kim, Deog Yoon

    1999-01-01

    Biochemical markers of bone turnover has received increasing attention over the past few years, because of the need for sensitivity and specific tool in the clinical investigation of osteoporosis. Bone markers should be unique to bone, reflect changes of bone less, and should be correlated with radiocalcium kinetics, histomorphometry, or changes in bone mass. The markers also should be useful in monitoring treatment efficacy. Although no bone marker has been established to meet all these criteria, currently osteocalcin and pyridinium crosslinks are the most efficient markers to assess the level of bone turnover in the menopausal and senile osteoporosis. Recently, N-terminal telopeptide (NTX), C-terminal telopeptide (CTX) and bone specific alkaline phosphatase are considered as new valid markers of bone turnover. Recent data suggest that CTX and free deoxypyridinoline could predict the subsequent risk of hip fracture of elderly women. Treatment of postmenopausal women with estrogen, calcitonin and bisphosphonates demonstrated rapid decrease of the levels of bone markers that correlated with the long-term increase of bone mass. Factors such as circadian rhythms, diet, age, sex, bone mass and renal function affect the results of biochemical markers and should be appropriately adjusted whenever possible. Each biochemical markers of bone turnover may have its own specific advantages and limitations. Recent advances in research will provide more sensitive and specific assays

  10. Biochemical markers of bone turnover

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Deog Yoon [College of Medicine, Kyunghee Univ., Seoul (Korea, Republic of)

    1999-08-01

    Biochemical markers of bone turnover has received increasing attention over the past few years, because of the need for sensitivity and specific tool in the clinical investigation of osteoporosis. Bone markers should be unique to bone, reflect changes of bone less, and should be correlated with radiocalcium kinetics, histomorphometry, or changes in bone mass. The markers also should be useful in monitoring treatment efficacy. Although no bone marker has been established to meet all these criteria, currently osteocalcin and pyridinium crosslinks are the most efficient markers to assess the level of bone turnover in the menopausal and senile osteoporosis. Recently, N-terminal telopeptide (NTX), C-terminal telopeptide (CTX) and bone specific alkaline phosphatase are considered as new valid markers of bone turnover. Recent data suggest that CTX and free deoxypyridinoline could predict the subsequent risk of hip fracture of elderly women. Treatment of postmenopausal women with estrogen, calcitonin and bisphosphonates demonstrated rapid decrease of the levels of bone markers that correlated with the long-term increase of bone mass. Factors such as circadian rhythms, diet, age, sex, bone mass and renal function affect the results of biochemical markers and should be appropriately adjusted whenever possible. Each biochemical markers of bone turnover may have its own specific advantages and limitations. Recent advances in research will provide more sensitive and specific assays.

  11. Tiludronate: bone pharmacology and safety.

    Science.gov (United States)

    Bonjour, J P; Ammann, P; Barbier, A; Caverzasio, J; Rizzoli, R

    1995-11-01

    The pharmacological properties of tiludronate (4-chlorophenyl)thiomethylene bisphosphonate), a sulfured bisphosphonate, have been characterized in a series of preclinical in vivo and in vitro studies. In vivo, tiludronate exerts a dose-dependent inhibitory activity on bone resorption. This property was demonstrated in several animal models, including rats, ewes, and dogs, when bone resorption was induced by administration of retinoid acid or parathyroid hormone, or by immobilization, ovariectomy or orchidectomy. By uncoupling bone resorption from bone formation, tiludronate can induce a positive calcium and phosphate balance. When administered either continuously or intermittently to ovariectomized osteoporotic rats, tiludronate promotes a significant increase in bone mass. This positive effect is associated with an increase in mechanical resistance. Bone tolerance studies indicate that tiludronate is a safe compound with an appreciable therapeutic margin since it can effectively inhibit bone resorption without reducing bone mineralization and strength. In vitro, tiludronate added to bone tissue culture inhibits calcium release, lysosomal enzyme secretion and collagen matrix degradation when induced by various stimulators of bone resorption. At the cellular level, tiludronate does not appear to exert its inhibitory effect on bone resorption by impairing either the recruitment, the migration or the fusion of osteoclast precursors. Tiludronate could act on mature osteoclasts by reducing their capacity to secrete proton into the resorption space and also by favoring their detachment from the bone matrix. The available preclinical data indicate that tiludronate should be an efficacious bisphosphonate in the management of clinical conditions characterized by excessive bone resorption.

  12. Enzymatic maceration of bone

    DEFF Research Database (Denmark)

    Uhre, Marie-Louise; Eriksen, Anne Marie; Simonsen, Kim Pilkjær

    2015-01-01

    This proof of concept study investigates the removal of soft tissue from human ribs with the use of two common methods: boiling with a laundry detergent and using enzymes. Six individuals were autopsied, and one rib from each individual was removed for testing. Each rib was cut into pieces...... and afterwards macerated by one of the two methods. DNA extraction was performed to see the effect of the macerations on DNA preservation. Furthermore, the bone pieces were examined in a stereomicroscope to assess for any bone damage. The results demonstrated that both methods removed all flesh/soft tissue from...

  13. Porcine bone marrow: extraction procedure and characterization by bone type.

    Science.gov (United States)

    Calhoun, C M; Schnell, T D; Mandigo, R W

    1998-12-01

    Data on porcine and bovine bone marrow composition indicate high calcium content, which may be erroneously elevated owing to the marrow recovery process. A method of bone marrow recovery was developed that involved passing marrow extracted from bone through a filter-press mechanism to remove very fine bone particles and dust, allowing a more accurate analysis of marrow. Calcium values were reduced approximately 90% and ash values reduced more than 50% compared to other reported data. The new recovery method did not require sawing away the hard bone and it removed particulate that may have interfered with analyses. Bone marrow was characterized by bone type. Rib bone marrow had higher protein, iron, non-heme iron and total pigment than scapula, aitch/hip bone or vertebrae marrow. Fat ranged from 17·81 to 26·76% and calcium ranged from 27·25 to 44·33mg 100g(-1) among bone types. The pH of bone marrow ranged from 7·14 to 7·53. Bone marrow appears to contribute to some of the properties of meat obtained from advanced meat recovery systems.

  14. A novel bio-inorganic bone implant containing deglued bone ...

    Indian Academy of Sciences (India)

    Deglued bone (DGB) which is a by-product of bone glue industries and has the close crystallographic similarities of hydroxyapatite was used as main component in the preparation of bone implant. Chitosan was prepared from the exoskeleton of prawn (Pinaeus indicus, family Crustaceae) which is a by-product of seafood ...

  15. Analysis of bone mineral density of human bones for strength ...

    Indian Academy of Sciences (India)

    indirect indicator of osteoporosis and fracture risk. This medical bone density is not the true physical “density” of the bone, which would be computed as mass per volume. Dual-energy X-ray absorptiometry (DXA, previously DEXA), a means of measuring BMD, is the most widely used and most thoroughly studied bone ...

  16. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x- ... x-ray machine is a compact apparatus that can be taken to the patient in a hospital ...

  17. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... little information about muscles, tendons or joints. An MRI may be more useful in identifying bone and ... bones and the spinal cord can be evaluated). MRI can also detect subtle or occult fractures or ...

  18. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... to produce pictures of any bone in the body. It is commonly used to diagnose fractured bones ... x-rays involves exposing a part of the body to a small dose of ionizing radiation to ...

  19. Breast Cancer and Bone Loss

    Science.gov (United States)

    ... Menopause Map Featured Resource Find an Endocrinologist Search Breast Cancer and Bone Loss July 2010 Download PDFs English ... G. Komen Foundation What is the link between breast cancer and bone loss? Certain treatments for breast cancer ...

  20. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... are the limitations of Bone X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray ( ... leg (shin), ankle or foot. top of page What are some common uses of the procedure? A ...

  1. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... your doctor to view and assess bone fractures, injuries and joint abnormalities. This exam requires little to ... fusion, joint replacement and fracture reductions. look for injury, infection, arthritis , abnormal bone growths and bony changes ...

  2. Fractures (Broken Bones): First Aid

    Science.gov (United States)

    First aid Fractures (broken bones) Fractures (broken bones): First aid By Mayo Clinic Staff A fracture is a ... 10, 2018 Original article: http://www.mayoclinic.org/first-aid/first-aid-fractures/basics/ART-20056641 . Mayo Clinic ...

  3. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... tissues around or in bones. top of page How should I prepare? Most bone x-rays require ... is placed beneath the patient. top of page How does the procedure work? X-rays are a ...

  4. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

    ... Bone Health Featured Resource Find an Endocrinologist Search Vitamin D, Calcium, and Bone Health Download PDFs English Espanol ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin D ...

  5. Bone quality: the determinants of bone strength and fragility.

    Science.gov (United States)

    Fonseca, Hélder; Moreira-Gonçalves, Daniel; Coriolano, Hans-Joachim Appell; Duarte, José Alberto

    2014-01-01

    Bone fragility is a major health concern, as the increased risk of bone fractures has devastating outcomes in terms of mortality, decreased autonomy, and healthcare costs. Efforts made to address this problem have considerably increased our knowledge about the mechanisms that regulate bone formation and resorption. In particular, we now have a much better understanding of the cellular events that are triggered when bones are mechanically stimulated and how these events can lead to improvements in bone mass. Despite these findings at the molecular level, most exercise intervention studies reveal either no effects or only minor benefits of exercise programs in improving bone mineral density (BMD) in osteoporotic patients. Nevertheless, and despite that BMD is the gold standard for diagnosing osteoporosis, this measure is only able to provide insights regarding the quantity of bone tissue. In this article, we review the complex structure of bone tissue and highlight the concept that its mechanical strength stems from the interaction of several different features. We revisited the available data showing that bone mineralization degree, hydroxyapatite crystal size and heterogeneity, collagen properties, osteocyte density, trabecular and cortical microarchitecture, as well as whole bone geometry, are determinants of bone strength and that each one of these properties may independently contribute to the increased or decreased risk of fracture, even without meaningful changes in aBMD. Based on these findings, we emphasize that while osteoporosis (almost) always causes bone fragility, bone fragility is not always caused just by osteoporosis, as other important variables also play a major role in this etiology. Furthermore, the results of several studies showing compelling data that physical exercise has the potential to improve bone quality and to decrease fracture risk by influencing each one of these determinants are also reviewed. These findings have meaningful clinical

  6. Cellular and Molecular Mechanisms of Bone Remodeling*

    OpenAIRE

    Raggatt, Liza J.; Partridge, Nicola C.

    2010-01-01

    Physiological bone remodeling is a highly coordinated process responsible for bone resorption and formation and is necessary to repair damaged bone and to maintain mineral homeostasis. In addition to the traditional bone cells (osteoclasts, osteoblasts, and osteocytes) that are necessary for bone remodeling, several immune cells have also been implicated in bone disease. This minireview discusses physiological bone remodeling, outlining the traditional bone biology dogma in light of emerging ...

  7. Chondroblastoma of temporal bone

    Energy Technology Data Exchange (ETDEWEB)

    Tanohta, K.; Noda, M.; Katoh, H.; Okazaki, A.; Sugiyama, S.; Maehara, T.; Onishi, S.; Tanida, T.

    1986-07-01

    The case of a 55-year-old female with chondroblastoma arising from the left temporal bone is presented. Although 10 cases of temporal chondroblastoma have been reported, this is the first in which plain radiography, pluridirectional tomography, computed tomography (CT) and angiography were performed. We discuss the clinical and radiological aspects of this rare tumor.

  8. Bone scintigraphy in chondroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Humphry, A.; Gilday, D.L.; Brown, R.G.

    1980-11-01

    Scintigraphy in 3 patients with chondroblastoma showed that the tumors were hyperemic and avidly accumulated the radionuclide. These changes were also present in adjacent normal bone, but to a lesser degree. This suggests that radionuclide uptake in chondroblastoma is a function of the blood supply to the tumor rather than primary matrix extraction.

  9. Bone scintiscanning in metastases

    International Nuclear Information System (INIS)

    Cayla, J.; Basset, J.Y.

    1986-01-01

    The three fold interest of bone scintiscanning is discussed in relation to 182 cases of bone metastases of various origins. Firstly, this technic facilitates early diagnosis of invasion of the bone by the detection of metastatic lesions which, in 7.7% of cases are still infraradiologic, or even of reflex algodystrophy of the legs, which can be detected only from a scintiscan, long before X-ray plates can show the lumbar metastasis which is responsible. Secondly, the method is able to pick up more metastasic sites in 54.4% of cases than can be detected by X-ray; this is confirmed by investigation of the S/R ratio (ratio of the number of strongly binding sites to the number of sites showing radiologic damage) which is greater than unity for a considerable period. Thirdly, repeated scintiscanography provides a prognosis, because the survival time appears to be fairly closely correlated with the regression, stability or extension of strongly binding sites, although a ''flare phenomenon'' may give the erroneous impression that the metastatic process has deteriorated. Repeated scintiscanography also provides a good way of evaluating the efficacy of medical treatment, particularly in the case of bone metastases of mammary or prostatic origin. Sometimes, the decision for or against prophylactic or palliative orthopedic surgery may be based to a considerable extent on data provided by scintiscan [fr

  10. Bone island and leprosy

    Energy Technology Data Exchange (ETDEWEB)

    Carpintero, P.; Garcia-Frasquet, A. [Department of Orthopaedic Surgery, Cordoba University, Medical School, Reina Sofia University Hospital, Cordoba (Spain); Tarradas, E. [Department of Imaging, Cordoba University, Medical School, Cordoba (Spain); Logrono, C. [Department of Dermatology, Reina Sofia University Hospital, Cordoba (Spain); Carrascal, A. [Department of Radiology, Infanta Elena Hospital, Huelva (Spain); Carreto, A. [Department of Radiology, Reina Sofia University Hospital, Cordoba (Spain)

    1998-06-01

    Objective. To determine the incidence of bone islands in leprosy patients. Design. X-rays of feet and hands of patients with Hansen`s disease (leprosy) were reviewed retrospectively. A second group of related age- and sex-matched patients who did not have Hansen`s disease was used for control purposes. Controls had undergone hand or foot X-rays during diagnosis of other pathologies. The patients with Hansen`s disease were compared with the control group, and were also analyzed as subgroups with different types of leprosy. The results were subjected to statistical analysis. Patients. Ninety patients with Hansen`s disease were randomly selected for this study. Patients who had had ulcers on hands or feet were excluded from the study. Results and conclusions. Bone islands were demonstrated in 20 patients with Hansen`s disease; no bone islands were observed in the controls. This was statistically significant (P<0.01). Bone islands were only seen in patients with lepromatous leprosy and borderline types but were not demonstrated in patients with tuberculoid leprosy. There was also a statistically significant relationship for a disease duration of 15 years or more. The cause of this raised incidence of enostosis in leprosy patients is not clear, but there may be a genetic predisposition in patients with leprosy, or it may be a side effect of leprosy, especially the lepromatous form. (orig.) With 4 figs., 2 tabs., 9 refs.

  11. Bone marrow aspiration

    Science.gov (United States)

    Bain, B

    2001-01-01

    Bone marrow aspiration biopsies are carried out principally to permit cytological assessment but also for immunophenotypic, cytogenetic, molecular genetic, and other specialised investigations. Often, a trephine biopsy is carried out as part of the same procedure. Bone marrow aspirations should be carried out by trained individuals who are aware of the indications, contraindications, and hazards of the procedure. They should follow a standard operating procedure. The operator should have made an adequate assessment of clinical and haematological features to ensure both that appropriate indications exist and that all relevant tests are performed. For the patient's comfort and safety, the posterior iliac crest is generally the preferred site of aspiration. Films of aspirated marrow and, when appropriate, films of crushed particles should be made and labelled. Once thoroughly dry, films should be fixed and stained. As a minimum, a Romanowsky stain and a Perls' stain are required. A cover slip should be applied. The bone marrow films should be assessed and reported in a systematic manner so that nothing of importance is overlooked, using a low power, then intermediate, then high power objective. A differential count should be performed. An interpretation of the findings, in the light of the clinical and haematological features, should be given. The report should be signed or computer authorised, using a secure password, and issued in a timely manner. Key Words: bone marrow aspirate • haematological diagnosis PMID:11533068

  12. Sodium and bone health

    DEFF Research Database (Denmark)

    Teucher, B.; Dainty, J. R.; Spinks, C. A.

    2008-01-01

    High salt intake is a well-recognized risk factor for osteoporosis because it induces calciuria, but the effects of salt on calcium metabolism and the potential impact on bone health in postmenopausal women have not been fully characterized. This study investigated adaptive mechanisms in response...

  13. Making silent bones speak

    DEFF Research Database (Denmark)

    Ivanovaite, Livija; Jensen, Mathias Paul Bjørnevad; Philippsen, Bente

    2017-01-01

    Orphaned osseous tools very often perceived as having high aesthetical value but carrying minimal information. The article illustrates the research potential of these artefacts with a case study of Mesolithic stray finds from Lithuania. Four bone points from the Šventoji river, Vaikantonys, Obšrū...

  14. Temporal bone imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lemmerling, Marc [Algemeen Ziekenhuis Sint-Lucas, Gent (Belgium). Dept. of Radiology; Foer, Bert de (ed.) [Sint-Augustinus Ziekenhuis, Wilrijk (Belgium). Dept. of Radiology

    2015-04-01

    Complete overview of imaging of normal and diseased temporal bone. Straightforward structure to facilitate learning. Detailed consideration of newer imaging techniques, including the hot topic of diffusion-weighted imaging. Includes a chapter on anatomy that will be of great help to the novice interpreter of imaging findings. Excellent illustrations throughout. This book provides a complete overview of imaging of normal and diseased temporal bone. After description of indications for imaging and the cross-sectional imaging anatomy of the area, subsequent chapters address the various diseases and conditions that affect the temporal bone and are likely to be encountered regularly in clinical practice. The classic imaging methods are described and discussed in detail, and individual chapters are included on newer techniques such as functional imaging and diffusion-weighted imaging. There is also a strong focus on postoperative imaging. Throughout, imaging findings are documented with the aid of numerous informative, high-quality illustrations. Temporal Bone Imaging, with its straightforward structure based essentially on topography, will prove of immense value in daily practice.

  15. Bones of the Earth

    Science.gov (United States)

    Correa, Jose Miguel

    2014-01-01

    The film "Bones of the Earth" (Riglin, Cunninham & Correa, 2014) is an experience in collective inquiry and visual creation based on arts-based research. Starting from the meeting of different subjectivities and through dialogue, planning, shooting and editing, an audiovisual text that reconstructs a reflexive process of collective…

  16. Are Bones Alive?

    Science.gov (United States)

    Caravita, Silvia; Falchetti, Elisabetta

    2005-01-01

    Many studies have investigated the classification of living things. Our study deals with a different problem: the attribution of life to one component of a living organism, specifically the bones. The task involves not only specifying what we mean by "alive", but also requires "informed thinking" leading to an understanding of…

  17. Bone Marrow Matters

    Science.gov (United States)

    Dunne, Mark; Maklad, Rania; Heaney, Emma

    2014-01-01

    As a final-year student teacher specialising in primary science, Emma Heaney faced the challenge of having to plan, organise, and conduct a small-scale, classroom-based research project. She had to teach about bones in the final block practice session and thought it would be a good idea to bring in some biological specimens obtained from the local…

  18. Calcium and bones

    Science.gov (United States)

    ... eat in their diet. Vitamin D is the hormone that helps the gut absorb more calcium. Many older adults have common risks that make bone health worse. Calcium intake in the diet (milk, cheese, yogurt) is low. Vitamin D levels are ...

  19. Bone scintigraphy in psoriasis

    International Nuclear Information System (INIS)

    Hahn, K.; Thiers, G.; Eissner, D.; Holzmann, H.; Frankfurt Univ.

    1980-01-01

    Since 1973 bone scintigraphy using sup(99m)Tc-phosphate-complexes was carried out in 382 patients with psoriasis. For comparison with the results of nuclear medicine, roentgenologic and clinical findings a group af 121 patients with psoriasis aged between 11 and 74 years was compared to a group of 42 patients aged between 20 and 49 years without roentgenologic and clinical signs of psoriasis arthritis. We found by means of isotope investigation that an essentially greater part of the bones adjacent to the joints was involved than was expected according to X-ray and clinical findings. In addition, in 205 patients with psoriasis whole-body scintigraphy, using sup(99m)Tc-MDP, was carried out since 1977/78. In 17 patients we found an increased accumulation of activity in the region of extraarticular structures of the skull as well as of the skeletal thorax. According to these results we conclude that in addition to the clinically and roentgenologically defined psoriatic arthritis in patients with psoriasis an osteopathy may exist, which can only be demonstrated by skeletal scintigraphy and which is localized in bones adjacent to the joints but can also be demonstrated in the region of extraarticular bones. (orig.) [de

  20. Bone scintiscanning in metastases

    Energy Technology Data Exchange (ETDEWEB)

    Cayla, J.; Basset, J.Y.

    1986-05-01

    The three fold interest of bone scintiscanning is discussed in relation to 182 cases of bone metastases of various origins. Firstly, this technic facilitates early diagnosis of invasion of the bone by the detection of metastatic lesions which, in 7.7% of cases are still infraradiologic, or even of reflex algodystrophy of the legs, which can be detected only from a scintiscan, long before X-ray plates can show the lumbar metastasis which is responsible. Secondly, the method is able to pick up more metastasic sites in 54.4% of cases than can be detected by X-ray; this is confirmed by investigation of the S/R ratio (ratio of the number of strongly binding sites to the number of sites showing radiologic damage) which is greater than unity for a considerable period. Thirdly, repeated scintiscanography provides a prognosis, because the survival time appears to be fairly closely correlated with the regression, stability or extension of strongly binding sites, although a ''flare phenomenon'' may give the erroneous impression that the metastatic process has deteriorated. Repeated scintiscanography also provides a good way of evaluating the efficacy of medical treatment, particularly in the case of bone metastases of mammary or prostatic origin. Sometimes, the decision for or against prophylactic or palliative orthopedic surgery may be based to a considerable extent on data provided by scintiscan.

  1. Food and Your Bones

    Science.gov (United States)

    ... Experts Home › Patients › Treatment for Osteoporosis › Nutrition Nutrition Food For Thought Quiz How do you get your ... above View Answers Loading ... Nutritional Guide View Now Food and Your Bones — Osteoporosis Nutrition Guidelines The food ...

  2. Electron Microscopy of Bone

    NARCIS (Netherlands)

    Everts, V.; Hoeben, K. A.

    2012-01-01

    Mineralized tissues like bone, dentin and mineralized cartilage are difficult to prepare for ultrastructural analysis. In general, the higher the level of mineralization is, the more difficult it is to obtain ultrathin sections of these tissue. Tissues with a low level of mineral, e.g. from young

  3. Eosinophilic Granuloma in Jaw Bone

    African Journals Online (AJOL)

    GB

    alveolar bone. Involvement of other bones is ruled out by nucleotide imaging study. CONCLUSION: EG should be considered as a differential diagnosis whenever there is ... KEYWORDS: Eosinophilic granuloma, langerhans cell histiocytosis, oral manifestations, alveolar bone .... enough to initiate healing and spontaneous.

  4. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z X-ray (Radiography) - Bone Bone x-ray uses a very small ... X-ray (Radiography)? What is Bone X-ray (Radiography)? An x-ray (radiograph) is a noninvasive medical ...

  5. Bone grafting options in children.

    Science.gov (United States)

    Betz, Randal R; Lavelle, William F; Samdani, Amer F

    2010-08-01

    Retrospective review of the literature. To review the current literature as well as recent trends in bone grafting techniques available for children. The currently accepted gold standard in bone grafting for adolescent idiopathic scoliosis (AIS) is autogenous iliac crest. Due to questions concerning complications such as donor site pain, other options have been explored, including various allograft sources, demineralized bone matrix, and bone morphogenetic protein. A review of the current medical literature was completed and additional case examples are presented. A review of the literature reveals that up to 31% of patients have persistent pain at 2 years post surgery when autogenous iliac crest bone graft is harvested. Allograft supplementation of local autograft has been demonstrated in the literature to be as effective as autogenous iliac crest bone grafting in contributing to a successful posterior spinal fusion in patients with AIS. Modern demineralized bone matrix formulations have been found in both animal models as well as in a recent retrospective clinical review to contribute to a successful posterior spinal fusion in AIS. Bone morphogenetic protein has been shown to contribute to a successful posterior spinal fusion in complex pediatric spinal deformity patients. At 2 years follow-up, patients who underwent a posterior instrumented spinal fusion that was not augmented with any bone graft appear to have successful spinal fusions. Although autogenous iliac bone graft remains the benchmark to which bone grafting materials are compared, other options including the placement of no bone graft at all provides similar fusion rates in patients with AIS.

  6. [Imaging diagnostics of bone sarcomas].

    Science.gov (United States)

    Krämer, J A; Gübitz, R; Beck, L; Heindel, W; Vieth, V

    2014-06-01

    Bone tumors and especially bone sarcomas are rare lesions of the skeletal system in comparison to the much more frequently occurring bone metastases. Despite the relative rarity they are important differential diagnoses of bone lesions. The aim of this article is to give the reader an insight into the fundamentals of the primary imaging of bone sarcomas and to illustrate this with the help of two examples (e.g. osteosarcoma and chondrosarcoma). The foundation of the imaging of bone sarcomas is the radiograph in two planes. This method delivers important information on bone tumors. This information should be analyzed with the help of the Lodwick classification, the configuration of periosteal reactions and a possible reaction of the cortex. A possible tumor matrix and the localization within the skeleton or within long bones also provide important information for differential diagnostic delimitation. Magnetic resonance imaging (MRI) with specific adapted bone tumor sequences allows an exact local staging of a bone sarcoma. In addition to local imaging a compartmental MRI which illustrates the entire extent of tumor-bearing bone and the adjacent joints should be performed to rule out possible skip lesions. The most common distant metastases of osteosarcoma and chondrosarcoma occur in the lungs; therefore, a computed tomography (CT) of the chest is part of staging. Other imaging methods, such as CT of the tumor, positron emission tomography CT (PET-CT), bone scan and whole body MRI supplement the imaging depending on tumor type.

  7. Bone regeneration during distraction osteogenesis

    NARCIS (Netherlands)

    Amir, L.R.; Everts, V.; Bronckers, A.L.J.J.

    2009-01-01

    Bone has the capacity to regenerate in response to injury. During distraction osteogenesis, the renewal of bone is enhanced by gradual stretching of the soft connec- tive tissues in the gap area between two separated bone segments. This procedure has received much clinical atten- tion as a way to

  8. Oral Health and Bone Disease

    Science.gov (United States)

    ... that the loss of alveolar bone mineral density leaves bone more susceptible to periodontal bacteria, increasing the ... bone density will have a favorable impact on dental health. Bisphosphonates, a group of medications available for the treatment of osteoporosis, have been linked to the development ...

  9. Bone formation using human demineralised bone matrix (Grafton) for the treatment of bone cysts in children.

    Science.gov (United States)

    Hass, H-J; Krause, H; Kroker, S; Wagemann, W; Meyer, F

    2007-02-01

    Bone cysts, in particular solitary bone cysts, are the most frequent cause of pathological fractures in children. However, there is still a great variety of regimens used to treat these lesions. Since demineralised bone matrix (DBM) is commercially available, we aimed to use this material for the consolidation of bones diagnosed as fragile because of cyst formation. Each of the 7 bone cysts as well as one enchondroma filled with DBM showed a continuous decrease in bone transparency over a period of two years (mean 8 months). A significant decrease in bone transparency and simultaneous cortical remodelling was radiographically detected in these cases as the specific hallmark of an initiated graft incorporation after 3 to 4 months. It was demonstrated that it is possible to heal children within an acceptable period of time using DBM to fill the cystic lesion. DBM appears to be a reasonable and beneficial alternative for the treatment of bone cysts offering both osteoinduction and osteoconductive features.

  10. Osteoinduction of bone grafting materials for bone repair and regeneration.

    Science.gov (United States)

    García-Gareta, Elena; Coathup, Melanie J; Blunn, Gordon W

    2015-12-01

    Regeneration of bone defects caused by trauma, infection, tumours or inherent genetic disorders is a clinical challenge that usually necessitates bone grafting materials. Autologous bone or autograft is still considered the clinical "gold standard" and the most effective method for bone regeneration. However, limited bone supply and donor site morbidity are the most important disadvantages of autografting. Improved biomaterials are needed to match the performance of autograft as this is still superior to that of synthetic bone grafts. Osteoinductive materials would be the perfect candidates for achieving this task. The aim of this article is to review the different groups of bone substitutes in terms of their most recently reported osteoinductive properties. The different factors influencing osteoinductivity by biomaterials as well as the mechanisms behind this phenomenon are also presented, showing that it is very limited compared to osteoinductivity shown by bone morphogenetic proteins (BMPs). Therefore, a new term to describe osteoinductivity by biomaterials is proposed. Different strategies for adding osteoinductivity (BMPs, stem cells) to bone substitutes are also discussed. The overall objective of this paper is to gather the current knowledge on osteoinductivity of bone grafting materials for the effective development of new graft substitutes that enhance bone regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Bone marrow oedema associated with benign and malignant bone tumours

    Energy Technology Data Exchange (ETDEWEB)

    James, S.L.J. [Department of Radiology, Royal Orthopaedic Hospital, Birmingham, B31 2AP (United Kingdom)], E-mail: steven.james@roh.nhs.uk; Panicek, D.M. [Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021 (United States); Davies, A.M. [Department of Radiology, Royal Orthopaedic Hospital, Birmingham, B31 2AP (United Kingdom)

    2008-07-15

    Bone marrow oedema is associated with a wide variety of pathological processes including both benign and malignant bone tumours. This imaging finding in relation to intraosseous tumours can aid in providing a more focused differential diagnosis. In this review, we will discuss the MR imaging of bone marrow oedema surrounding intraosseous neoplasms. The different pulse sequences used in differentiating underlying tumour from surrounding oedema are discussed along with the role of dynamic contrast enhanced MRI. Benign lesions commonly associated with bone marrow oedema include osteoid osteoma, osteoblastoma, chondroblastoma and Langerhan's cell histiocytosis. Metastases and malignant primary bone tumours such as osteosarcoma, Ewing's sarcoma and chondrosarcoma may also be surrounded by bone marrow oedema. The imaging findings of these conditions are reviewed and illustrated. Finally, the importance of bone marrow oedema in assessment of post chemotherapeutic response is addressed.

  12. Bone microarchitecture and bone mineral density in multiple sclerosis

    DEFF Research Database (Denmark)

    Olsson, A; Oturai, A B; Søndergaard, H B

    2018-01-01

    BACKGROUND: Multiple sclerosis (MS) patients are at increased risk of reduced bone mineral density (BMD) and fractures. The aetiology of bone loss in MS is unclear. Trabecular bone score (TBS) is a novel analytical tool that provides a measurement of the bone microarchitecture. Decreased TBS...... included. TBS was calculated using TBS iNsight software (MediMaps® ). Multivariable regression analyses were performed with information on smoking, alcohol, glucocorticoid (GC) treatment, sun exposure, physical activity, vitamin D and BMI. RESULTS: Trabecular bone score was not significantly different from...... patients, suggesting that BMD alone, and not the bone microarchitecture, is affected in MS. However, larger studies are needed to verify these findings and to establish the role of TBS in MS. As in the background population, physical activity and non-smoking habits are associated with better bone health...

  13. Bone scintigraphy in detection of bone invasion by oral carcinoma

    International Nuclear Information System (INIS)

    Higashi, Kotaro; Wakao, Hiromi; Ikuta, Hiroyuki; Kashima, Isamu; Everhart, F.R. Jr.

    1996-01-01

    Detecting osseous involvement is clinically important in the management of oral carcinoma. Thirty-one patients with osseous involvement due to oral carcinoma who underwent panoramic radiography and bone scintigraphy were evaluated retrospectively. Bone scintigraphy confirmed osseous involvement in all 31 (100%) of these patients. In 27 (87%) of 31 patients with osseous involvement, both the panoramic radiogram and bone scintigram were positive. In the remaining four patients (13%), bone scintigram was positive for mandibular or maxillary invasion, while panoramic radiogram was negative. There were no instances of an abnormal radiogram with a normal bone scintigram. These findings strongly suggest that bone scintigraphy is more sensitive than panoramic radiography in detecting osseous involvement of the mandible and maxilla due to oral carcinoma. Furthermore, bone scintigraphy was a critical pre-surgical tool in determining the extent of the osseous involvement. (author)

  14. Bone marrow oedema associated with benign and malignant bone tumours

    International Nuclear Information System (INIS)

    James, S.L.J.; Panicek, D.M.; Davies, A.M.

    2008-01-01

    Bone marrow oedema is associated with a wide variety of pathological processes including both benign and malignant bone tumours. This imaging finding in relation to intraosseous tumours can aid in providing a more focused differential diagnosis. In this review, we will discuss the MR imaging of bone marrow oedema surrounding intraosseous neoplasms. The different pulse sequences used in differentiating underlying tumour from surrounding oedema are discussed along with the role of dynamic contrast enhanced MRI. Benign lesions commonly associated with bone marrow oedema include osteoid osteoma, osteoblastoma, chondroblastoma and Langerhan's cell histiocytosis. Metastases and malignant primary bone tumours such as osteosarcoma, Ewing's sarcoma and chondrosarcoma may also be surrounded by bone marrow oedema. The imaging findings of these conditions are reviewed and illustrated. Finally, the importance of bone marrow oedema in assessment of post chemotherapeutic response is addressed

  15. Lrp5 functions in bone to regulate bone mass.

    Science.gov (United States)

    Cui, Yajun; Niziolek, Paul J; MacDonald, Bryan T; Zylstra, Cassandra R; Alenina, Natalia; Robinson, Daniel R; Zhong, Zhendong; Matthes, Susann; Jacobsen, Christina M; Conlon, Ronald A; Brommage, Robert; Liu, Qingyun; Mseeh, Faika; Powell, David R; Yang, Qi M; Zambrowicz, Brian; Gerrits, Han; Gossen, Jan A; He, Xi; Bader, Michael; Williams, Bart O; Warman, Matthew L; Robling, Alexander G

    2011-06-01

    The human skeleton is affected by mutations in low-density lipoprotein receptor-related protein 5 (LRP5). To understand how LRP5 influences bone properties, we generated mice with osteocyte-specific expression of inducible Lrp5 mutations that cause high and low bone mass phenotypes in humans. We found that bone properties in these mice were comparable to bone properties in mice with inherited mutations. We also induced an Lrp5 mutation in cells that form the appendicular skeleton but not in cells that form the axial skeleton; we observed that bone properties were altered in the limb but not in the spine. These data indicate that Lrp5 signaling functions locally, and they suggest that increasing LRP5 signaling in mature bone cells may be a strategy for treating human disorders associated with low bone mass, such as osteoporosis.

  16. Evolutionary patterns of bone histology and bone compactness in xenarthran mammal long bones.

    Science.gov (United States)

    Straehl, Fiona R; Scheyer, Torsten M; Forasiepi, Analía M; MacPhee, Ross D; Sánchez-Villagra, Marcelo R

    2013-01-01

    Bone microstructure reflects physiological characteristics and has been shown to contain phylogenetic and ecological signals. Although mammalian long bone histology is receiving increasing attention, systematic examination of the main clades has not yet been performed. Here we describe the long bone microstructure of Xenarthra based on thin sections representing twenty-two species. Additionally, patterns in bone compactness of humeri and femora are investigated. The primary bone tissue of xenarthran long bones is composed of a mixture of woven, parallel-fibered and lamellar bone. The vascular canals have a longitudinal, reticular or radial orientation and are mostly arranged in an irregular manner. Concentric rows of vascular canals and laminar organization of the tissue are only found in anteater bones. The long bones of adult specimens are marked by dense Haversian bone, a feature that has been noted for most groups of mammals. In the long bones of armadillos, secondary osteons have an oblique orientation within the three-dimensional bone tissue, thus resulting in their irregular shape when the bones are sectioned transversely. Secondary remodeling is generally more extensive in large taxa than in small taxa, and this could be caused by increased loading. Lines of arrested growth are assumed to be present in all specimens, but they are restricted to the outermost layer in bones of armadillos and are often masked by secondary remodeling in large taxa. Parameters of bone compactness show a pattern in the femur that separates Cingulata and Pilosa (Folivora and Vermilingua), with cingulates having a lower compactness than pilosans. In addition, cingulates show an allometric relationship between humeral and femoral bone compactness.

  17. Autologous bone graft versus demineralized bone matrix in internal fixation of ununited long bones

    OpenAIRE

    Rubenbauer Bianka; Löffler Thomas; Zaspel Johannes; Wittmann Alexandra; Pieske Oliver; Trentzsch Heiko; Piltz Stefan

    2009-01-01

    Abstract Background Non-unions are severe complications in orthopaedic trauma care and occur in 10% of all fractures. The golden standard for the treatment of ununited fractures includes open reduction and internal fixation (ORIF) as well as augmentation with autologous-bone-grafting. However, there is morbidity associated with the bone-graft donor site and some patients offer limited quantity or quality of autologous-bone graft material. Since allogene bone-grafts are introduced on the marke...

  18. Oscillatory fluid flow induces the osteogenic lineage commitment of mesenchymal stem cells: The effect of shear stress magnitude, frequency, and duration.

    Science.gov (United States)

    Stavenschi, Elena; Labour, Marie-Noelle; Hoey, David A

    2017-04-11

    A potent regulator of bone anabolism is physical loading. However, it is currently unclear whether physical stimuli such as fluid shear within the marrow cavity is sufficient to directly drive the osteogenic lineage commitment of resident mesenchymal stem cells (MSC). Therefore, the objective of the study is to employ a systematic analysis of oscillatory fluid flow (OFF) parameters predicted to occur in vivo on early MSC osteogenic responses and late stage lineage commitment. MSCs were exposed to OFF of 1Pa, 2Pa and 5Pa magnitudes at frequencies of 0.5Hz, 1Hz and 2Hz for 1h, 2h and 4h of stimulation. Our findings demonstrate that OFF elicits a positive osteogenic response in MSCs in a shear stress magnitude, frequency, and duration dependent manner that is gene specific. Based on the mRNA expression of osteogenic markers Cox2, Runx2 and Opn after short-term fluid flow stimulation, we identified that a regime of 2Pa shear magnitude and 2Hz frequency induces the most robust and reliable upregulation in osteogenic gene expression. Furthermore, long-term mechanical stimulation utilising this regime, elicits a significant increase in collagen and mineral deposition when compared to static control demonstrating that mechanical stimuli predicted within the marrow is sufficient to directly drive osteogenesis. Copyright © 2017. Published by Elsevier Ltd.

  19. [Osteoporosis and quality of bone].

    Science.gov (United States)

    Štěpán, Jan

    2018-01-01

    The risk of osteoporotic fracture is determined collectively by bone mineral density, bone mass, architecture and properties of the mineral and organic matrix composite. Changes in these distinct aspects of quality of bone with age, estrogen deficiency, diseases leading to increased risk of fracture and differential mode of action of antiresorptive and bone anabolic treatments have to be considered in clinical therapeutic strategies. In patients at high risk of low impact fracture, sequential therapy switching to antiresorptives after patients have an adequate response to 2 years teriparatide may be the optimal strategy of long term therapy.Key words: aging - bone quality - osteoporosis - prevention - therapy.

  20. Metastases to bone in medulloblastoma

    International Nuclear Information System (INIS)

    Vieco, P.T.; Azouz, E.M.; Hoeffel, J.C.

    1989-01-01

    Medulloblastoma is a relatively common intracranial neoplasm in childhood. Its extraneural spread was, until recently, thought to be a rare occurrence. Metastases are most commonly to bone. Five patients with medulloblastoma metastatic to bone are presented, and findings are compared to those of previous reports. Two of the five cases showed patchy extensive osteosclerosis of the pelvis and/or proximal femora. One case had concurrent lymph node involvement. In patients with past or present medulloblastoma and bone pain, metastases to bone should be excluded. Medulloblastoma metastatic to bone is a rare cause of extensive osteosclerosis. (orig.)

  1. Bone Anchored Hearing Aid

    Science.gov (United States)

    2002-01-01

    Executive Summary Objective The objective of this health technology policy assessment was to determine the effectiveness and cost-effectiveness of bone-anchored hearing aid (BAHA) in improving the hearing of people with conduction or mixed hearing loss. The Technology The (BAHA) is a bone conduction hearing device that includes a titanium fixture permanently implanted into the mastoid bone of the skull and an external percutaneous sound processor. The sound processor is attached to the fixture by means of a skin penetrating abutment. Because the device bypasses the middle ear and directly stimulates the cochlea, it has been recommended for individuals with conduction hearing loss or discharging middle ear infection. The titanium implant is expected to last a lifetime while the external sound processor is expected to last 5 years. The total initial device cost is approximately $5,300 and the external sound processor costs approximately $3,500. Review of BAHA by the Medical Advisory Secretariat The Medical Advisory Secretariat’s review is a descriptive synthesis of findings from 36 research articles published between January 1990 and May 2002. Summary of Findings No randomized controlled studies were found. The evidence was derived from level 4 case series with relative small sample sizes (ranging from 30-188). The majority of the studies have follow-up periods of eight years or longer. All except one study were based on monaural BAHA implant on the side with the best bone conduction threshold. Safety Level 4 evidence showed that BAHA has been be implanted safely in adults and children with success rates of 90% or higher in most studies. No mortality or life threatening morbidity has been reported. Revision rates for tissue reduction or resiting were generally under 10% for adults but have been reported to be as high as 25% in pediatric studies. Adverse skin reaction around the skin penetration site was the most common complication reported. Most of these

  2. Bone Metabolism in Anorexia Nervosa

    Science.gov (United States)

    Fazeli, Pouneh K.; Klibanski, Anne

    2014-01-01

    Anorexia nervosa (AN), a psychiatric disorder predominantly affecting young women, is characterized by self-imposed chronic nutritional deprivation and distorted body image. AN is associated with a number of medical co-morbidities including low bone mass. The low bone mass in AN is due to an uncoupling of bone formation and bone resorption, which is the result of hormonal adaptations aimed at decreasing energy expenditure during periods of low energy intake. Importantly, the low bone mass in AN is associated with a significant risk of fractures and therefore treatments to prevent bone loss are critical. In this review, we discuss the hormonal determinants of low bone mass in AN and treatments that have been investigated in this population. PMID:24419863

  3. MRI in bone marrow lesions

    International Nuclear Information System (INIS)

    Linden, A.; Theissen, P.; Schauerte, G.; Schicha, H.; Diehl, V.

    1989-01-01

    MRI has the potential to demonstrate bone marrow pathology due to its good soft tissue contrast. Inflammation and necrosis can be detected very early before there is evidence of radiological changes. In bone tumors intramedullary infiltration can be visualized in addition to soft tissue changes. Metastases of bone and bone marrow, especially in spinal and pelvic regions, are well depicted, often before bone scintigraphy yields pathological findings. In haematological disorders MRI permits follow-up studies due to its good reproducibility. Infiltration by malignant lymphoma and multiple myeloma and its extension in bone marrow can be visualized by MRI, too. However, the most common pathological MRI findings in bone marrow are not very specific, and final diagnosis requires further clinical or histological information. (orig.) [de

  4. Electromechanical Properties of Bone Tissue.

    Science.gov (United States)

    Regimbal, Raymond L.

    Discrepancies between calculated and empirical properties of bone are thought to be due to a general lack of consideration for the extent and manner(s) with which bone components interact at the molecular level. For a bone component in physiological fluid or whenever two phases are in contact, there is a region between the bulk phases called the electrical double layer which is marked by a separation of electric charges. For the purpose of studying electrical double layer interactions, the method of particle microelectrophoresis was used to characterize bone and its major constituents on the basis of the net charge they bear when suspended in ionic media of physiological relevance. With the data presented as pH versus zeta (zeta ) potential, the figures reveal an isoelectric point (IEP) for bone mineral near pH 8.6, whereas intact and EDTA demineralized bone tissue both exhibit IEPs near pH 5.1. While these data demonstrate the potential for a significant degree of coulombic interaction between the bone mineral and organic constituent double layers, it was also observed that use of inorganic phosphate buffers, as a specific marker for bone mineral, resulted in (1) an immediate reversal, from positive to negative, of the bone mineral zeta potential (2) rendered the zeta potential of intact bone more negative in a manner linearly dependent on both time and temperature and (3) had no affect on demineralized bone (P load for a 3 day period. While it is thus demonstrated that the major inorganic and organic phases of bone are electromechanically coupled, a thermodynamic consideration of the data suggests that the nature of the bond is to preserve mineral and organic phase electroneutralities by participating in electrical double layer interactions. The results are discussed in terms of bone mechanical modeling, electrokinetic properties, aging, tissue-implant compatibility and the etiologies of bone pathologic conditions.

  5. Bone- and bone marrow scintigraphy in Gaucher disease type 1

    Energy Technology Data Exchange (ETDEWEB)

    Mikosch, P. [Dept. of Nuclear Medicine and Endocrinology, State Hospital Klagenfurt (Austria); Dept. of Internal Medicine II, State Hospital Klagenfurt (Austria); Zitter, F. [Dept. of Internal Medicine II, State Hospital Klagenfurt (Austria); Gallowitsch, H.J.; Lind, P. [Dept. of Nuclear Medicine and Endocrinology, State Hospital Klagenfurt (Austria); Wuertz, F. [Dept. of Pathology, State Hospital Klagenfurt (Austria); Mehta, A.B.; Hughes, D.A. [Lysosomal Storage Disorder Unit, Dept. of Academic Haematology, Royal Free and Univ. Coll. Medical School, London (United Kingdom)

    2008-07-01

    Scintigraphy is a method for imaging metabolism and should be viewed as complimentary to morphological imaging. Bone and bone marrow scintigraphy can particularly contribute to the detection of focal disease in Gaucher disease. In bone crises it can discriminate within three days after pain onset between local infection and aseptic necrosis. A further advantage of bone- and bone marrow scintigraphy is the visualization of the whole skeleton within one setting. Whole body imaging for focal lesions might thus be an objective in GD, in particular in patients complaining of several painful sites. Direct imaging of bone marrow deposits in GD by MIBI scintigraphy might be of special interest in children in whom bone marrow undergoes a developmental conversion from red to yellow marrow in the ap-pendicular skeleton. MRI interpretation in young GD patients is thus difficult in order to estimate the exact amount and extent of bone marrow infiltration by Gaucher cells. 99mTc-MIBI scintigraphy with its direct visualization of lipid storage could thus add interesting additional information not shown with other methods including MRI. Although MRI is the most accepted imaging modality in assessing the skeletal status in GD, a selective use of scintigraphy for imaging bone and bone marrow may add information in the evaluation of patients with Gaucher disease.

  6. Bone marrow macrophages support prostate cancer growth in bone.

    Science.gov (United States)

    Soki, Fabiana N; Cho, Sun Wook; Kim, Yeo Won; Jones, Jacqueline D; Park, Serk In; Koh, Amy J; Entezami, Payam; Daignault-Newton, Stephanie; Pienta, Kenneth J; Roca, Hernan; McCauley, Laurie K

    2015-11-03

    Resident macrophages in bone play important roles in bone remodeling, repair, and hematopoietic stem cell maintenance, yet their role in skeletal metastasis remains under investigated. The purpose of this study was to determine the role of macrophages in prostate cancer skeletal metastasis, using two in vivo mouse models of conditional macrophage depletion. RM-1 syngeneic tumor growth was analyzed in an inducible macrophage (CSF-1 receptor positive cells) ablation model (MAFIA mice). There was a significant reduction in tumor growth in the tibiae of macrophage-ablated mice, compared with control non-ablated mice. Similar results were observed when macrophage ablation was performed using liposome-encapsulated clodronate and human PC-3 prostate cancer cells where tumor-bearing long bones had increased numbers of tumor associated-macrophages. Although tumors were consistently smaller in macrophage-depleted mice, paradoxical results of macrophage depletion on bone were observed. Histomorphometric and micro-CT analyses demonstrated that clodronate-treated mice had increased bone volume, while MAFIA mice had reduced bone volume. These results suggest that the effect of macrophage depletion on tumor growth was independent of its effect on bone responses and that macrophages in bone may be more important to tumor growth than the bone itself. In conclusion, resident macrophages play a pivotal role in prostate cancer growth in bone.

  7. Bone- and bone marrow scintigraphy in Gaucher disease type 1

    International Nuclear Information System (INIS)

    Mikosch, P.; Zitter, F.; Gallowitsch, H.J.; Lind, P.; Wuertz, F.; Mehta, A.B.; Hughes, D.A.

    2008-01-01

    Scintigraphy is a method for imaging metabolism and should be viewed as complimentary to morphological imaging. Bone and bone marrow scintigraphy can particularly contribute to the detection of focal disease in Gaucher disease. In bone crises it can discriminate within three days after pain onset between local infection and aseptic necrosis. A further advantage of bone- and bone marrow scintigraphy is the visualization of the whole skeleton within one setting. Whole body imaging for focal lesions might thus be an objective in GD, in particular in patients complaining of several painful sites. Direct imaging of bone marrow deposits in GD by MIBI scintigraphy might be of special interest in children in whom bone marrow undergoes a developmental conversion from red to yellow marrow in the ap-pendicular skeleton. MRI interpretation in young GD patients is thus difficult in order to estimate the exact amount and extent of bone marrow infiltration by Gaucher cells. 99mTc-MIBI scintigraphy with its direct visualization of lipid storage could thus add interesting additional information not shown with other methods including MRI. Although MRI is the most accepted imaging modality in assessing the skeletal status in GD, a selective use of scintigraphy for imaging bone and bone marrow may add information in the evaluation of patients with Gaucher disease

  8. Aging and bone. X-ray bone densitometry

    International Nuclear Information System (INIS)

    Morita, Rikushi

    1994-01-01

    Bone mass at all ages of the individuals is the integration of genetic factors, nutrition, physical exercise, hormonal environments, and other factors influencing the bone. It is also a measurable risk factor for osteoporosis which may subsequently cause bone fractures. Thus measuring bone mass is required to predict the probability of developing bone fractures subsequent to osteoporosis, and to diagnose osteoporosis, and to manage the osteoporosis patient. This paper discusses bone mineral measurements according to their characteristics and clinical application. Methodology for measuring bone mass has rapidly progressed during the past 15 years, which covers photodensitometry, photon absorptiometry (single energy X-ray absorptiometry and dual energy X-ray absorptiometry), quantitative CT, and ultrasound. These techniques have allowed noninvasive measurement of bone mineral density in any site of the skeleton with high accuracy and precision, although a single use of the technique cannot satisfy the complete clinical requirements. Thus the most appropriate method for measuring bone mineral density is important to monitor bone mass change and according to the specific site. (N.K.)

  9. Bone graft viability evaluated by three phase bone scan

    International Nuclear Information System (INIS)

    Ljiljana Jaukovic Rajko Spaic; Marijan Novakovic; Srbislav Stosic

    2004-01-01

    Bone defects resulting war injury can be replaced by microvascular bone grafts from fibula. Aim: The aim of this study was to assess the value of three phase (3P) bone scintigraphy in the early detection of the bone graft complications. Method: 3P bone scans were performed in four patients (two after mandible reconstruction with micro vascular fibular bone grafts, one after fibular transplantation for ulnar and one with humeral reconstruction). First dynamic phase scan was performed immediately after iv injection of 740 MBq Tc- 99m DPD, acquiring 15 two seconds duration frames. Second, early static scan was performed during next 300 seconds, and third, delayed scan three hours later. All scans were obtained under the bone graft region. The scans were evaluated using ROI under graft region and the corresponding contra lateral area. Blood flow in graft region was determined using first phase scan, and tracer uptake in the same region was determined using second and third phase scans. Results: in all patients blood flow in graft region was particularly normal. Tracer uptake in one of two patients with mandible reconstruction was diffusely increased in graft, strongly suggesting infection; In the other patient delayed scan showed no tracer uptake in graft center .Both patients with ulnar and humeral reconstruction showed only slightly decreased tracer uptake in bone grafts. 3 phase bone scintigraphy may play a role in the evaluation of bone graft viability by predicting the infection and necrosis. (authors)

  10. Role of bone marrow macrophages in controlling homeostasis and repair in bone and bone marrow niches.

    Science.gov (United States)

    Kaur, Simranpreet; Raggatt, Liza Jane; Batoon, Lena; Hume, David Arthur; Levesque, Jean-Pierre; Pettit, Allison Robyn

    2017-01-01

    Macrophages, named for their phagocytic ability, participate in homeostasis, tissue regeneration and inflammatory responses. Bone and adjacent marrow contain multiple functionally unique resident tissue macrophage subsets which maintain and regulate anatomically distinct niche environments within these interconnected tissues. Three subsets of bone-bone marrow resident tissue macrophages have been characterised; erythroblastic island macrophages, haematopoietic stem cell niche macrophages and osteal macrophages. The role of these macrophages in controlling homeostasis and repair in bone and bone marrow niches is reviewed in detail. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Heritability of bone mineral density.

    Science.gov (United States)

    François, S; Benmalek, A; Guaydier-Souquières, G; Sabatier, J P; Marcelli, C

    1999-03-01

    To evaluate the influence of genetic background as a determinant of peak bone mass. We compared lumbar spine bone mineral density in 175 girls with a bone age of 16 years or older and in their premenopausal mothers. We also investigated the influence of a family history of osteoporosis on lumbar spine bone mineral density in 275 women and their 559 daughters. In the 175 mother-daughter pairs, heritability (h2) was significantly different from 0 (P < 0.0001) for lumbar spine bone mineral density (h2 = 53%; 95% confidence interval [95% CI] = 28.5-77.6%), bone mineral content (h2 = 62.3%; 95% CI = 37.7-86.8%), bone mineral density adjusted for body mass index (h2 = 56%; CI = 31.5-80.5%), and bone mineral content adjusted for body mass index (h2 = 68.2%; CI = 43.6-92.7%). However, the heritability estimations lacked accuracy, as shown by the wide 95% CIs. Osteopenia and osteoporosis were found in 16.4% and 1% of the mothers, respectively. In the subgroup defined by osteopenia or osteoporosis in the mother, lumbar spine bone mineral density was significantly higher in the daughters than in the mothers (0.994 +/- 0.095 g/cm2 versus 0.895 +/- 0.098 g/cm2; P < 0.0001), whereas the opposite was true in the subgroup defined by normal bone mass in the mothers (1.068 +/- 0.110 g/cm2 versus 1.109 +/- 0.098 g/cm2; P = 0.0003). Nevertheless, lumbar spine bone mineral density was significantly lower in the daughters of low-bone-mass women than in those of normal-bone-mass women (0.994 +/- 0.009 g/cm2 versus 1.069 +/- 0.012 g/cm2; P = 0.0006). These findings suggest a role of genetic factors inherited from the father and also indicate that bone mass gains during adulthood contribute to achievement of the optimal peak bone mass. In the family history study, bone mass was lower in the subjects with a family history of osteoporosis (123 of the 559 daughters, Z-scores normalized for height, weight, and pubertal status: bone mineral density Z-score, -0.054 +/- 1.104; bone mineral

  12. Multiscale Modeling of Bone

    Science.gov (United States)

    2014-12-01

    risk ?,” Equine Veterinary J., vol. 42, no. 2, pp. 174– 180, Mar. 2010. [127] J. J. Sciote and T. J. Morris, “Skeletal muscle function and fibre...shear properties of fibrils, fibers, and lamellar layers. A layered composite model assessed cortical and trabecular bone while a simple finite element...to be assessed . It was found that the distribution of hydroxyapatite within the tropocollagen matrix at the fibril level influences the macroscale

  13. Battling Brittle Bones

    Science.gov (United States)

    2002-01-01

    The accuDEXA(R) Bone Mineral Density Assessment System, manufactured by Schick Technologies, Inc., utilizes "camera on a chip" sensor technology invented and developed by NASA's Jet Propulsion Laboratory. Schick's accuDEXA system offers several advantages over traditional osteoporosis tests, which assess bone density loss in the hip and spine, and require specialized personnel to conduct. With accuDEXA, physicians can test the entire body's bone density at a peripheral site, such as the finger, without applying gels or having patients remove garments. Results are achieved in 30 seconds and printed out in less than a minute, compared to the estimated exam time of 15 minutes for hip and spine density analyses. Schick has also applied the CMOS APS technology to a new software product that performs dental radiography using up to 90 percent less radiation exposure than conventional X-rays. Called Computed Dental Radiography(R), the new digital imaging product utilizes an electronic sensor in place of X-ray film to generate sharp and clear images that appear on a computer screen within 3 seconds, and can be enlarged and enhanced to identify problems.

  14. HIV and bone disease.

    Science.gov (United States)

    Stone, Benjamin; Dockrell, David; Bowman, Christine; McCloskey, Eugene

    2010-11-01

    Advances in management have resulted in a dramatic decline in mortality for individuals infected with human immunodeficiency virus (HIV). This decrease in mortality, initially the result of improved prophylaxis and treatment of opportunistic infections but later mediated by the use of highly-active antiretroviral therapy (HAART) has led to the need to consider long-term complications of the disease itself, or its treatment. Bone disease is increasingly recognised as a concern. The prevalence of reduced BMD and possibly also fracture incidence are increased in HIV-positive individuals compared with HIV-negative controls. There are many potential explanations for this - an increased prevalence of established osteoporosis risk factors in the HIV-positive population, a likely direct effect of HIV infection itself and a possible contributory role of ARV therapy. At present, the assessment of bone disease and fracture risk remains patchy, with little or no guidance on identifying those at increased risk of reduced BMD or fragility fracture. Preventative and therapeutic strategies with bone specific treatments need to be developed. Limited data suggest bisphosphonates may be beneficial in conjunction with vitamin D and calcium supplementation in the treatment of reduced BMD in HIV-infected patients but larger studies of longer duration are needed. The safety and cost-effectiveness of these and other treatments needs to be evaluated. Copyright © 2010. Published by Elsevier Inc.

  15. Bone Metabolism on ISS Missions

    Science.gov (United States)

    Smith, S. M.; Heer, M. A.; Shackelford, L. C.; Zwart, S. R.

    2014-01-01

    Spaceflight-induced bone loss is associated with increased bone resorption (1, 2), and either unchanged or decreased rates of bone formation. Resistive exercise had been proposed as a countermeasure, and data from bed rest supported this concept (3). An interim resistive exercise device (iRED) was flown for early ISS crews. Unfortunately, the iRED provided no greater bone protection than on missions where only aerobic and muscular endurance exercises were available (4, 5). In 2008, the Advanced Resistive Exercise Device (ARED), a more robust device with much greater resistance capability, (6, 7) was launched to the ISS. Astronauts who had access to ARED, coupled with adequate energy intake and vitamin D status, returned from ISS missions with bone mineral densities virtually unchanged from preflight (7). Bone biochemical markers showed that while the resistive exercise and adequate energy consumption did not mitigate the increased bone resorption, bone formation was increased (7, 8). The typical drop in circulating parathyroid hormone did not occur in ARED crewmembers. In 2014, an updated look at the densitometry data was published. This study confirmed the initial findings with a much larger set of data. In 42 astronauts (33 male, 9 female), the bone mineral density response to flight was the same for men and women (9), and those with access to the ARED did not have the typical decrease in bone mineral density that was observed in early ISS crewmembers with access to the iRED (Figure 1) (7). Biochemical markers of bone formation and resorption responded similarly in men and women. These data are encouraging, and represent the first in-flight evidence in the history of human space flight that diet and exercise can maintain bone mineral density on long-duration missions. However, the maintenance of bone mineral density through bone remodeling, that is, increases in both resorption and formation, may yield a bone with strength characteristics different from those

  16. Flow-induced crystallization of a nano composite of poly(butylene adipate-co-terephthalate)/montmorillonite; Cinetica de cristalizacao induzida por fluxo de nanocomposito de poli(butileno adipato-co-tereftalato)/montmorilonita

    Energy Technology Data Exchange (ETDEWEB)

    Bonel, Alan B. [Universidade Federal de Sao Carlos. UFSCar, Departamento de Engenharia de Materiais DEMa, SP (Brazil); Rego, Bruna T.; Beatrice, Cesar A.G.; Marini, Juliano; Bretas, Rosario E.S., E-mail: bretas@ufscar.br [Universidade Federal de Sao Carlos. UFSCar, Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais, SP (Brazil)

    2011-07-01

    Poly(butylene adipate-co-terephthalate) (PBAT) with 5wt% of an organically modified montmorillonite with polar surfactant was prepared by melt blending in a co-rotational twin-screw extruder at 160 degree C. 100rpm and 1 kg/h. Both pure polymer and nano composite were characterized by wide measurements. The study of the flow-induced crystallization was also done by rheological measurements, monitoring the viscosity as a function of time. The nano clay's lamellas were intercalated in the polymer m loss moduli of the nano composite, at low frequencies, showed that the particles of the nano clay were well dispersed and distributed thru the PBAT matrix. Finally, the presence of the nano clay's particles reduced the induction tim crystals growth, due to the strong interactions with the PBAT chains. (author)

  17. Denosumab for bone diseases: translating bone biology into targeted therapy.

    Science.gov (United States)

    Tsourdi, Elena; Rachner, Tilman D; Rauner, Martina; Hamann, Christine; Hofbauer, Lorenz C

    2011-12-01

    Signalling of receptor activator of nuclear factor-κB (RANK) ligand (RANKL) through RANK is a critical pathway to regulate the differentiation and activity of osteoclasts and, hence, a master regulator of bone resorption. Increased RANKL activity has been demonstrated in diseases characterised by excessive bone loss such as osteoporosis, rheumatoid arthritis and osteolytic bone metastases. The development and approval of denosumab, a fully MAB against RANKL, has heralded a new era in the treatment of bone diseases by providing a potent, targeted and reversible inhibitor of bone resorption. This article summarises the molecular and cellular biology of the RANKL/RANK system and critically reviews preclinical and clinical studies that have established denosumab as a promising novel therapy for metabolic and malignant bone diseases. We will discuss the potential indications for denosumab along with a critical review of safety and analyse its potential within the concert of established therapies.

  18. Bone disease in primary hyperparathyroidism

    Science.gov (United States)

    Bandeira, Francisco; Cusano, Natalie E.; Silva, Barbara C.; Cassibba, Sara; Almeida, Clarissa Beatriz; Machado, Vanessa Caroline Costa; Bilezikian, John P.

    2015-01-01

    Bone disease in severe primary hyperparathyroidism (PHPT) is described classically as osteitis fibrosa cystica (OFC). Bone pain, skeletal deformities and pathological fractures are features of OFC. Bone mineral density is usually extremely low in OFC, but it is reversible after surgical cure. The signs and symptoms of severe bone disease include bone pain, pathologic fractures, proximal muscle weakness with hyperreflexia. Bone involvement is typically characterized as salt-and-pepper appearance in the skull, bone erosions and bone resorption of the phalanges, brown tumors and cysts. In the radiography, diffuse demineralization is observed, along with pathological fractures, particularly in the long bones of the extremities. In severe, symptomatic PHPT, marked elevation of the serum calcium and PTH concentrations are seen and renal involvement is manifested by nephrolithiasis and nephrocalcinosis. A new technology, recently approved for clinical use in the United States and Europe, is likely to become more widely available because it is an adaptation of the lumbar spine DXA image. Trabecular bone score (TBS) is a gray-level textural analysis that provides an indirect index of trabecular microarchitecture. Newer technologies, such as high-resolution peripheral quantitative computed tomography (HR-pQCT), have provided further understanding of the microstructural skeletal features in PHPT. PMID:25166047

  19. Bone tumors of the spine and sacral bone

    International Nuclear Information System (INIS)

    Freyschmidt, Juergen

    2010-01-01

    Bone tumors and tumorlike lesions of the spine are rare entities and may harbour diagnostic problems. In this article we discuss the epidemiology, topographic aspects, clinical and radiologic features as well as the diagnostic management of vertebral bone tumors. Entities that should be more familiar to the radiologist (i.e. osteoid osteoma, osteoblastoma, hemangioma, giant cell tumor, chordoma, aneurysmal bone cyst) are considered in more detail. (orig.)

  20. Development of Bone Remodeling Model for Spaceflight Bone Physiology Analysis

    Science.gov (United States)

    Pennline, James A.; Werner, Christopher R.; Lewandowski, Beth; Thompson, Bill; Sibonga, Jean; Mulugeta, Lealem

    2015-01-01

    Current spaceflight exercise countermeasures do not eliminate bone loss. Astronauts lose bone mass at a rate of 1-2% a month (Lang et al. 2004, Buckey 2006, LeBlanc et al. 2007). This may lead to early onset osteoporosis and place the astronauts at greater risk of fracture later in their lives. NASA seeks to improve understanding of the mechanisms of bone remodeling and demineralization in 1g in order to appropriately quantify long term risks to astronauts and improve countermeasures. NASA's Digital Astronaut Project (DAP) is working with NASA's bone discipline to develop a validated computational model to augment research efforts aimed at achieving this goal.

  1. Carbon nanohorns accelerate bone regeneration in rat calvarial bone defect

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Takao; Iizuka, Tadashi; Kanamori, Takeshi; Yokoyama, Atsuro [Department of Oral Functional Prosthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo, Hokkaido 060-8586 (Japan); Matsumura, Sachiko; Shiba, Kiyotaka [Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, 3-8-31, Ariake, koutou-ku, Tokyo 135-8550 (Japan); Yudasaka, Masako; Iijima, Sumio, E-mail: tkasai@den.hokudai.ac.jp [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

    2011-02-11

    A recent study showed that carbon nanohorns (CNHs) have biocompatibility and possible medical uses such as in drug delivery systems. It was reported that some kinds of carbon nanomaterials such as carbon nanotubes were useful for bone formation. However, the effect of CNHs on bone tissue has not been clarified. The purpose of this study was to evaluate the effect of CNHs on bone regeneration and their possible application for guided bone regeneration (GBR). CNHs dispersed in ethanol were fixed on a porous polytetrafluoroethylene membrane by vacuum filtration. Cranial defects were created in rats and covered by a membrane with/without CNHs. At two weeks, bone formation under the membrane with CNHs had progressed more than under that without CNHs and numerous macrophages were observed attached to CNHs. At eight weeks, there was no significant difference in the amount of newly formed bone between the groups and the appearance of macrophages was decreased compared with that at two weeks. Newly formed bone attached to some CNHs directly. These results suggest that macrophages induced by CNHs are related to bone regeneration. In conclusion, the present study indicates that CNHs are compatible with bone tissue and effective as a material for GBR.

  2. Carbon nanohorns accelerate bone regeneration in rat calvarial bone defect

    Science.gov (United States)

    Kasai, Takao; Matsumura, Sachiko; Iizuka, Tadashi; Shiba, Kiyotaka; Kanamori, Takeshi; Yudasaka, Masako; Iijima, Sumio; Yokoyama, Atsuro

    2011-02-01

    A recent study showed that carbon nanohorns (CNHs) have biocompatibility and possible medical uses such as in drug delivery systems. It was reported that some kinds of carbon nanomaterials such as carbon nanotubes were useful for bone formation. However, the effect of CNHs on bone tissue has not been clarified. The purpose of this study was to evaluate the effect of CNHs on bone regeneration and their possible application for guided bone regeneration (GBR). CNHs dispersed in ethanol were fixed on a porous polytetrafluoroethylene membrane by vacuum filtration. Cranial defects were created in rats and covered by a membrane with/without CNHs. At two weeks, bone formation under the membrane with CNHs had progressed more than under that without CNHs and numerous macrophages were observed attached to CNHs. At eight weeks, there was no significant difference in the amount of newly formed bone between the groups and the appearance of macrophages was decreased compared with that at two weeks. Newly formed bone attached to some CNHs directly. These results suggest that macrophages induced by CNHs are related to bone regeneration. In conclusion, the present study indicates that CNHs are compatible with bone tissue and effective as a material for GBR.

  3. LONG TERM EVOLUTION OF BONE RECONSTRUCTION WITH BONE GRAFT SUBSTITUTES

    Directory of Open Access Journals (Sweden)

    O. V. Martynenko

    2017-06-01

    Full Text Available The review involves clinical and experimental data, constitutive modeling, and computational investigations towards an understanding on how mechanical cyclic loads for long periods of time affect damage evolution in a reconstructed bone, as well as, lifetime reduction of bone graft substitutes after advanced core decompression. The outcome of the integrated model discussed in this paper will be how damage growth in femur after advanced core decompression subjected to mechanical cyclic loading under creep and fatigue conditions may be controlled in order to optimize design and processing of bone graft substitutes, and extend lifetime of bone substitutes.

  4. Clinical research of bone scan characteristics for metabolic bone diseases

    International Nuclear Information System (INIS)

    Zhu Ruisen; Luo Qiong; Lu Haikui; Chen Libo; Luo Quanyong

    2009-01-01

    Characteristic images of 99m Tc-MDP bone scintigraphy in patients with metabolic bone diseases (MBD) were analyzed and compared, in an attempt to improve the capability of differential diagnosis in this aspect. A total of 142 cases, clinically confirmed as (MBD), were categorized into six groups: hyperparathyroidism (117), renal osteodystrophy (4), Paget's disease (16), hypophosphatemic osteomalacia (2), Albers-Schonberg disease (2), and Brittle bone disease (1). They were diagnosed clinically or pathologically, and scanned with 99m Tc-MDP bone scintegraphy, from which the 142 MBD cases were classified into 4 types. The cases of Type I had increased amount of 99m Tc-MDP uptake in whole body bones, including hyperparathyroidism, Albers-Schonberg disease, brittle bone disease and renal osteodystrophy. The cases of Type II had high uptake of 99m Tc-MDP in local region of bones, including paget's disease, hypophosphatemic osteomalacia and hyperparathyroidism. A Type I case with pathological fracture or secondary osteopathy was classified as Type III. Type IV cases were in early stage of hyperparathyroidism, with normal bone scan image. Analysis of the characteristics of 99m Tc-MDP bone scintigraphic findings (locations, morphology and intensities) in patients with MBD may be helpful in the differential diagnosis of MBD, in association with the patient's history and X-ray data altogether. (authors)

  5. Differentiation of bone marrow cells with irradiated bone in vitro

    International Nuclear Information System (INIS)

    Toshiyuki Tominaga; Moritoshi Itoman; Izumi, T.; Wakita, R.; Uchino, M.

    1999-01-01

    Disease transmission or infection is an important issue in bone allograft, and irradiation is used for sterilization of graft bones. One of the advantages of bone allograft over biomaterials is that graft bones have osteoinductive factors such as growth factors. Irradiation is reported to decrease the osteoinductive activity in vivo. We investigated the osteoinductive activity of irradiated bone by alkaline phosphatase (ALP) activity in rat bone marrow cell culture. Bones (tibias and femurs of 12-week-old Wistar rats) were cleaned of adhering soft tissue, and the marrow was removed by washing. The bones were defatted, lyophilized, and cut into uniform 70 mg fragments. Then the Bone fragments were irradiated at either 10, 20, 25, 30, 40, or 50 kGy at JAERI. Bone marrow cells were isolated from tibias and femurs of 4-week-old Wistar rats. Cells were plated in tissue culture flask. When primary cultures reached confluence, cells were passaged (4 x 103 cell / cm2) to 6 wells plates. The culture medium consisted of minimum essential medium, 10% fetal bovine serum, ascorbic acid, and antibiotics. At confluence, a cell culture insert was set in the well, and an irradiated bone fragment was placed in it. Then, medium was supplemented with 10 mM ?-glycerophosphate and 1 x 10-8 M dexamethasone. Culture wells were stained by naphthol AS-MX phosphate, N,N-dimethyl formamide, Red violet LB salt on day 0, 7, 14. The density of ALP staining was analyzed by a personal computer. Without bones, ALP staining increased by 50% on day 7 and by 100% on day 14, compared with that on day 0. The other side, with bones irradiated at 30 kGy or lower, ALP staining increased by 150% on day 7, and by 180% on day 14, compared with that on day 0. In the groups of irradiated bones of 40 kGy or higher, the increase in ALP staining was less prominent compared with the groups of irradiated bones of 30 kGy or lower. In the groups of 0-30 kGy irradiation, ALP staining increased in the early period

  6. Mandibular reconstruction using bone allografts

    International Nuclear Information System (INIS)

    Chang Joon Yim

    1999-01-01

    Further understanding of bone healing mechanisms, bone physiology and bone biology, transplantation immunology, and development of Tissue Banking procedures has enabled oral and maxillofacial surgeons to reconstruct even the most difficult bony defects successfully with the preserved allogeneic bone implant. Although it had been known that bone allografts were clinically effective, its application has not been widespread until the reports of Inclan (I 942), Hyatt and Butler (I 950), and Wilson (I 95 1). Tissue Banking provides the surgeon with a readily available, relatively inexpensive, and relatively safe selection of allogeneic bone for clinical use. Now autogenous bone and allogeneic bone implants present a wide variety of surgical options to surgeons, whether used separately or in combination. The surgeons are able to make judicious and fruitful choices, only with a thorough knowledge of the above-mentioned biological principles and skillful techniques. Many kinds of bone grafting techniques have been tried for reconstructing defective osseous tissues of the oral and maxillofacial region, though they have varying degrees of success. The osseous defects which require grafting include those of various size, shape, position, or amount. Unlike autogenous grafts, whose function is to provide osteogenic cells, allografts are purely passive, offering only a matrix for the inductive phase of bone healing. The condition of the recipient bed is of primary importance, because the host must produce all of the essential elements for the bone allograft to become incorporated. Depending on the processing methods of the allogeneic bone, the bone graft materials have different qualities, different healing potentials and different indications. Proper selection of grafts and surgical techniques requires an understanding of graft immunology and the mechanisms of graft healing. The surgeons should know about the biological principles to raise the clinical success rate

  7. Bone-seeking therapeutic radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Srivastava Suresh C.

    2002-01-01

    Full Text Available Bone-seeking therapeutic radiopharmaceuticals are utilized on the basis of the radionuclide?s particulate emissions (primarily low to intermediate beta emission. The requirements therefore are different from those of bone imaging agents that consist mainly of short-lived single photon emitters. Lately, the therapeutic bone seeking radiopharmaceuticals have attained increasing importance due to their potential role in alleviating pain from osseous metastases in cancer patients, for the treatment of joint pain resulting from inflamed synovium (radiosynoviorthesis, or radiosynovectomy, or from various other forms of arthritic disease. There is, however, a paucity of published data on the bio-pharmacokinetics of these agents when used following intravenous administration for bone pain palliation. This paper will briefly review and summarize the presently available chemical and biopharmacokinetic information on the various clinically approved as well as experimental bone-localizing therapeutic radiopharmaceuticals, and make projections on their clinical application for the treatment of primary/metastatic cancer in bone.

  8. Trace elements and bone health.

    Science.gov (United States)

    Zofková, Ivana; Nemcikova, Petra; Matucha, Petr

    2013-08-01

    The importance of nutrition factors such as calcium, vitamin D and vitamin K for the integrity of the skeleton is well known. Moreover, bone health is positively influenced by certain elements (e.g., zinc, copper, fluorine, manganese, magnesium, iron and boron). Deficiency of these elements slows down the increase of bone mass in childhood and/or in adolescence and accelerates bone loss after menopause or in old age. Deterioration of bone quality increases the risk of fractures. Monitoring of homeostasis of the trace elements together with the measurement of bone density and biochemical markers of bone metabolism should be used to identify and treat patients at risk of non-traumatic fractures. Factors determining the effectivity of supplementation include dose, duration of treatment, serum concentrations, as well as interactions among individual elements. Here, we review the effect of the most important trace elements on the skeleton and evaluate their clinical importance.

  9. Ultrasonic guided waves in bone.

    Science.gov (United States)

    Moilanen, Petro

    2008-01-01

    Recent progress in quantitative ultrasound (QUS) has shown increasing interest toward measuring long bones by ultrasonic guided waves. This technology is widely used in the field of nondestructive testing and evaluation of different waveguide structures. Cortical bone provides such an elastic waveguide and its ability to sustain loading and resist fractures is known to be related to its mechanical properties at different length scales. Because guided waves could yield diverse characterizations of the bone's mechanical properties at the macroscopic level, the method of guided waves has a strong potential over the standardized bone densitometry as a tool for bone assessment. Despite this, development of guided wave methods is challenging, e.g., due to interferences and multiparametric inversion problems. This paper discusses the promises and challenges related to bone characterization by ultrasonic guided waves.

  10. Bone health in cancer patients

    DEFF Research Database (Denmark)

    Coleman, R; Body, J J; Aapro, M

    2014-01-01

    There are three distinct areas of cancer management that make bone health in cancer patients of increasing clinical importance. First, bone metastases are common in many solid tumours, notably those arising from the breast, prostate and lung, as well as multiple myeloma, and may cause major...... morbidity including fractures, severe pain, nerve compression and hypercalcaemia. Through optimum multidisciplinary management of patients with bone metastases, including the use of bone-targeted treatments such as potent bisphosphonates or denosumab, it has been possible to transform the course of advanced...... cancer for many patients resulting in a major reduction in skeletal complications, reduced bone pain and improved quality of life. Secondly, many of the treatments we use to treat cancer patients have effects on reproductive hormones, which are critical for the maintenance of normal bone remodelling...

  11. Artificial composite bone as a model of human trabecular bone: the implant-bone interface.

    Science.gov (United States)

    Grant, J A; Bishop, N E; Götzen, N; Sprecher, C; Honl, M; Morlock, M M

    2007-01-01

    The use of artificial bones in implant testing has become popular due to their low variability and ready availability. However, friction coefficients, which are critical to load transfer in uncemented implants, have rarely been compared between human and artificial bone, particularly for wet and dry conditions. In this study, the static and dynamic friction coefficients for four commercially used titanium surfaces (polished, Al(2)O(3) blasted, plasma sprayed, beaded) acting on the trabecular component of artificial bones (Sawbones) were compared to those for human trabecular bone. Artificial bones were tested in dry and wet conditions and normal interface stress was varied (0.25, 0.5, 1.0MPa). Friction coefficients were mostly lower for artificial bones than real bone. In particular, static friction coefficients for the dry polished surface were 20% of those for real bone and 42-61% for the dry beaded surface, with statistical significance (alphaartificial bone models for pre-clinical implant testing that rely on interface load transfer with trabecular bone for mechanical integrity can be particularly sensitive to surface finish and lubrication conditions.

  12. Playing with bone and fat

    DEFF Research Database (Denmark)

    Gimble, Jeffrey M.; Zvonic, Sanjin; Floyd, Z. Elisabeth

    2006-01-01

    The relationship between bone and fat formation within the bone marrow microenvironment is complex and remains an area of active investigation. Classical in vitro and in vivo studies strongly support an inverse relationship between the commitment of bone marrow-derived mesenchymal stem cells...... or stromal cells to the adipocyte and osteoblast lineage pathways. In this review, we focus on the recent literature exploring the mechanisms underlying these differentiation events and discuss their implications relevant to osteoporosis and regenerative medicine....

  13. Heterogeneity of spine bone density

    Energy Technology Data Exchange (ETDEWEB)

    Laskey, M.A.; Crisp, A.J.; Compston, J.E.; Khaw, K.-T. (Addenbrooke' s Hospital, Cambridge (United Kingdom))

    1993-05-01

    This short communication investigates how accurate bone density measured in the lumbar spine (L1-L4 or L2-L4) reflects the bone density of vertebrae where many compression fractures occur (T12 and L1). The ability of two dual-energy X-ray absorptiometers (Lunar DPX and Hologic QDR-1000) to determine the bone density of T12 was also investigated. (Author).

  14. Stress fractures and bone pain

    International Nuclear Information System (INIS)

    Groshar, D.; Even-Sapir, E.; Lam, M.; Israel, O.; Front, D.

    1984-01-01

    Stress fractures result from an unusual repetitive physical activity causing absorption of bone in excess of repair and bone formation. This leads to the weakening of the bone and subsequently to a fracture. It is a benign condition that if recognized in time does not need any treatment besides rest. However, if diagnosis is not made and physical activity continues it may result in severe injury to the bone and a frank fracture may result. Pain is the typical clinical feature and bone scintigraphy, being more sensitive than radiography, is done to establish early diagnosis. The presence of asymptomatic sites of abnormal bone uptake typical of stress fracture in which pain appeared only about 2 weeks after scintigraphy, drew the authors' attention to the question of how close is the relationship between stress fractures and bone pain. Sixty-four military recruits diagnosed as suffering from stress fracture were investigated in order to correlate sites with abnormal uptake of Tc-99m MDP on bone scintigraphy with sites of local pain. In 37 (58%) subjects multiple sites of abnormal uptake were recognised. Of 123 sites of abnormal uptake, 31 (25%) were asymptomatic. In three patients bone pain appeared at the site of the abnormal uptake two weeks after scintigraphy. Bone scintigraphy appears to be more sensitive than bone pain in the diagnosis of stress fractures. The osteoblastic activity which manifests itself by abnormal uptake appears in some cases earlier than the pain caused by the fracture. Present findings may suggest that under certain circumstances, in a population prone to stress fracture, bone scan should be considered as a screening method

  15. Investigations of Diabetic Bone Disease

    DEFF Research Database (Denmark)

    Linde, Jakob Starup

    Diabetes mellitus is associated with an increased risk of fracture with and current fracture predictors underestimate fracture risk in both type 1 and type 2 diabetes. Thus, further understanding of the underlying causes of diabetic bone disease may lead to better fracture predictors and preventive...... diabetes had lower bone turnover markers compared to patients with type 1 diabetes and bone mineral density and tissue stiffness were increased in patients with type 2 diabetes. The bone turnover markers were inversely associated with blood glucose in patients with diabetes and both an oral glucose...

  16. Bone anchorage: When and why?

    Directory of Open Access Journals (Sweden)

    Ahmet Nejat Erverdi

    2015-01-01

    Full Text Available Anchorage is the most important concept in biomechanics of orthodontics. In contemporary orthodontics, bone anchorage is a magic tool, which decreased the indication for extraoral appliances greatly and at the same time achieving stationary anchorage became possible. However, the indication for bone anchorage has to be clarified carefully. Skeletal open-bite treatment, effective molar distalization, Class III treatment by using chin anchorage, and space closure in severe minimal anchorage cases are some examples for bone anchorage supported orthodontic treatment. Here, we discussed three necessary usages of bone anchorage for different treatment modalities.

  17. Biomechanical properties of bone allografts

    International Nuclear Information System (INIS)

    Pelker, R.R.; Friedlaender, G.E.; Markham, T.C.

    1983-01-01

    The biomechanical properties of allograft bone can be altered by the methods chosen for its preservation and storage. These effects are minimal with deep-freezing or low-level radiation. Freeze-drying, however, markedly diminishes the torsional and bending strength of bone allografts but does not deleteriously affect the compressive or tensile strength. Irradiation of bone with more than 3.0 megarad or irradiation combined with freeze-drying appears to cause a significant reduction in breaking strength. These factors should be considered when choosing freeze-dried or irradiated allogeneic bone that will be subjected to significant loads following implantation

  18. Expansion of the CHR bone code system

    International Nuclear Information System (INIS)

    Farnham, J.E.; Schlenker, R.A.

    1976-01-01

    This report describes the coding system used in the Center for Human Radiobiology (CHR) to identify individual bones and portions of bones of a complete skeletal system. It includes illustrations of various bones and bone segments with their respective code numbers. Codes are also presented for bone groups and for nonbone materials

  19. Unifocal Bone Paracoccidioidomycosis, Brazil

    Science.gov (United States)

    Correa-de-Castro, Bruna; Pompilio, Mauricio A.; Odashiro, Danilo N.; Odashiro, Maçanori; Arão-Filho, Adalberto; Paniago, Anamaria M. M.

    2012-01-01

    We report a 47 year-old man from the State of Mato Grosso do Sul, Brazil, with unifocal tibial paracoccidioidomycosis. A radiograph showed an osteolytic lesion on the tibial middle third diaphysis. The diagnosis was confirmed by histopathologic analysis, and treatment with sulfamethoxazole and trimethoprim was started. After three months, the patient showed significant clinical improvement. Ten months after treatment, the patient showed lesion bone healing. This case describes the rare occurrence of an osteolytic lesion caused by endemic Paracoccidioides brasiliensis in Latin America. PMID:22403319

  20. Bones of the Earth

    Directory of Open Access Journals (Sweden)

    Jose Miguel Correa

    2014-06-01

    Full Text Available The film Bones of the Earth (Riglin, Cunninham & Correa, 2014 is an experience in collective inquiry and visual creation based on arts-based research. Starting from the meeting of different subjectivities and through dialogue, planning, shooting and editing, an audiovisual text that reconstructs a reflexive process of collective creation is built. A sense of community, on-going inquiry, connections and social commitment inform the creative process. As a result, the video’s nearly five intense minutes are a metaphor for the search for personal meaning, connection with nature and intersubjective positioning in a world that undergoes constant change.

  1. Bone marrow transplantation

    International Nuclear Information System (INIS)

    Storb, R.; Santos, G.W.

    1979-01-01

    Bone marrow transplantation has been increasingly used to treat patients with severe combined immunodeficiency diseases, severe aplastic anemia, and malignant hematologic diseases, especially leukemia. At the Workshop a number of problems were discussed, e.g., conditioning regimens aimed at overcoming the problem of marrow graft rejection and reducing the incidence of recurrent leukemia, prevention of graft-versus-host disease (GVHD), possible mechanisms involved in stable graft-host tolerance, graft-versus-leukemia effect in mice, and finally, the possible use of autologous marrow transplantation

  2. Interleukin-10 Inhibits Bone Resorption: A Potential Therapeutic Strategy in Periodontitis and Other Bone Loss Diseases

    OpenAIRE

    Zhang, Qian; Chen, Bin; Yan, Fuhua; Guo, Jianbin; Zhu, Xiaofeng; Ma, Shouzhi; Yang, Wenrong

    2014-01-01

    Periodontitis and other bone loss diseases, decreasing bone volume and strength, have a significant impact on millions of people with the risk of tooth loss and bone fracture. The integrity and strength of bone are maintained through the balance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively, so the loss of bone results from the disruption of such balance due to increased resorption or/and decreased formation of bone. The goal of therapies for diseases...

  3. Analysis of bone mineral density of human bones for strength ...

    Indian Academy of Sciences (India)

    The bone density (BMD) is a medical term normally referring to the amount of mineral matter per square centimetre of bones. Twenty-five patients (18 female and 7 male patients with a mean age of 71.3 years) undergoing both lumbar spine DXA scans and computed tomography imaging were evaluated to determine if HU ...

  4. Bone Activity Biomarkers and Bone Mineral Density in Children with ...

    African Journals Online (AJOL)

    Participants were subjected to biochemical assessment that included osteocalcin (OC), total and bone-specific alkaline phosphatase (tALP and bALP), isomerized beta form of type I collagen cross-linked telopeptide (β-Crosslaps) and intact parathyroid hormone (iPTH) levels. Patients with CKD also had their bone mineral ...

  5. Osseointegration of subperiosteal implants using bovine bone substitute and various membranes

    DEFF Research Database (Denmark)

    Aaboe, Merete; Schou, S.; Hjørting-Hansen, E.

    2000-01-01

    Osseointegration, subperiosteal implant, bone substitute, bovine bone, guided bone, regeneration, histology, rabbits......Osseointegration, subperiosteal implant, bone substitute, bovine bone, guided bone, regeneration, histology, rabbits...

  6. Raman spectroscopy of bone metastasis

    Science.gov (United States)

    Esmonde-White, Karen A.; Sottnik, Joseph; Morris, Michael; Keller, Evan

    2012-02-01

    Raman spectroscopy of bone has been used to characterize chemical changes occurring in diseases such as osteoporosis, osteoarthritis and osteomyelitis. Metastasis of cancer into bone causes changes to bone quality that are similar to those observed in osteoporosis, such as decreased bone strength, but with an accelerated timeframe. In particular, osteolytic (bone degrading) lesions in bone metastasis have a marked effect on patient quality of life because of increased risk of fractures, pain, and hypercalcemia. We use Raman spectroscopy to examine bone from two different mouse models of osteolytic bone metastasis. Raman spectroscopy measures physicochemical information which cannot be obtained through standard biochemical and histological measurements. This study was reviewed and approved by the University of Michigan University Committee on the Care and Use of Animals. Two mouse models of prostate cancer bone metastasis, RM1 (n=3) and PC3-luc (n=4) were examined. Tibiae were injected with RM1 or PC3-luc cancer cells, while the contralateral tibiae received a placebo injection for use as controls. After 2 weeks of incubation, the mice were sacrificed and the tibiae were examined by Raman microspectroscopy (λ=785 nm). Spectroscopic markers corresponding to mineral stoichiometry, bone mineralization, and mineral crystallinity were compared in spectra from the cancerous and control tibiae. X-ray imaging of the tibia confirmed extensive osteolysis in the RM1 mice, with tumor invasion into adjoining soft tissue and moderate osteolysis in the PC3-luc mice. Raman spectroscopic markers indicate that osteolytic lesions are less mineralized than normal bone tissue, with an altered mineral stoichiometry and crystallinity.

  7. Does methamphetamine affect bone metabolism?

    International Nuclear Information System (INIS)

    Tomita, Masafumi; Katsuyama, Hironobu; Watanabe, Yoko; Okuyama, Toshiko; Fushimi, Shigeko; Ishikawa, Takaki; Nata, Masayuki; Miyamoto, Osamu

    2014-01-01

    There is a close relationship between the central nervous system activity and bone metabolism. Therefore, methamphetamine (METH), which stimulates the central nervous system, is expected to affect bone turnover. The aim of this study was to investigate the role of METH in bone metabolism. Mice were divided into 3 groups, the control group receiving saline injections, and the 5 and 10 mg/kg METH groups (n = 6 in each group). All groups received an injection of saline or METH every other day for 8 weeks. Bone mineral density (BMD) was assessed by X-ray computed tomography. We examined biochemical markers and histomorphometric changes in the second cancellous bone of the left femoral distal end. The animals that were administered 5 mg/kg METH showed an increased locomotor activity, whereas those receiving 10 mg/kg displayed an abnormal and stereotyped behavior. Serum calcium and phosphorus concentrations were normal compared to the controls, whereas the serum protein concentration was lower in the METH groups. BMD was unchanged in all groups. Bone formation markers such as alkaline phosphatase and osteocalcin significantly increased in the 5 mg/kg METH group, but not in the 10 mg/kg METH group. In contrast, bone resorption markers such as C-terminal telopeptides of type I collagen and tartrate-resistant acid phosphatase 5b did not change in any of the METH groups. Histomorphometric analyses were consistent with the biochemical markers data. A significant increase in osteoblasts, especially in type III osteoblasts, was observed in the 5 mg/kg METH group, whereas other parameters of bone resorption and mineralization remained unchanged. These results indicate that bone remodeling in this group was unbalanced. In contrast, in the 10 mg/kg METH group, some parameters of bone formation were significantly or slightly decreased, suggesting a low turnover metabolism. Taken together, our results suggest that METH had distinct dose-dependent effects on bone turnover and that

  8. Multifocal bone and bone marrow lesions in children - MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Raissaki, Maria; Demetriou, Stelios; Spanakis, Konstantinos; Skiadas, Christos; Karantanas, Apostolos H. [University of Crete, Faculty of Medicine, Department of Radiology, University Hospital of Heraklion, Heraklion, Crete (Greece); Katzilakis, Nikolaos; Stiakaki, Eftichia [University of Crete, Faculty of Medicine, Department of Pediatric Hematology-Oncology, University Hospital of Heraklion, Heraklion, Crete (Greece); Velivassakis, Emmanouil G. [University Hospital of Heraklion, Orthopedic Clinic, Heraklion, Crete (Greece)

    2017-03-15

    Polyostotic bone and bone marrow lesions in children may be due to various disorders. Radiographically, lytic lesions may become apparent after loss of more than 50% of the bone mineral content. Scintigraphy requires osteoblastic activity and is not specific. MRI may significantly contribute to the correct diagnosis and management. Accurate interpretation of MRI examinations requires understanding of the normal conversion pattern of bone marrow in childhood and of the appearances of red marrow rests and hyperplasia. Differential diagnosis is wide: Malignancies include metastases, multifocal primary sarcomas and hematological diseases. Benign entities include benign tumors and tumor-like lesions, histiocytosis, infectious and inflammatory diseases, multiple stress fractures/reactions and bone infarcts/ischemia. (orig.)

  9. Bone SPECT/CT Localizes Increased Bone Metabolism and Subsequent Bone Resorption in Reflex Sympathetic Dystrophy.

    Science.gov (United States)

    Narimatsu, Hidetoshi; Nakahara, Tadaki; Kodama, Sayuri; Hisazumi, Hiromi; Tominaga, Shinichi; Ohkuma, Kiyoshi; Jinzaki, Masahiro

    2017-10-01

    A 64-year-old man with lung cancer with a history of revascularization of the occluded right femoral artery underwent bone scintigraphy, which showed intense uptake in the distal side of the right leg. The additional SPECT/CT clarified that the uptake was predominantly increased in the epiphyses of the right ankle and foot with possible osteopenia. One month later, follow-up SPECT/CT showed the manifestation of periosteal resorption in the hypermetabolic sites with slight decrease in bone metabolism. Radiological correlation between bone metabolism and subsequent bone resorption in addition to clinical symptoms in this patient suggested the diagnosis of reflex sympathetic dystrophy.

  10. Bone marrow edema syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Korompilias, Anastasios V.; Lykissas, Marios G.; Beris, Alexandros E. [University of Ioannina, Department of Orthopaedic Surgery, School of Medicine, Ioannina (Greece); Karantanas, Apostolos H. [University of Crete School of Medicine, Department of Radiology, Heraklion (Greece)

    2009-05-15

    Bone marrow edema syndrome (BMES) refers to transient clinical conditions with unknown pathogenic mechanism, such as transient osteoporosis of the hip (TOH), regional migratory osteoporosis (RMO), and reflex sympathetic dystrophy (RSD). BMES is primarily characterized by bone marrow edema (BME) pattern. The disease mainly affects the hip, the knee, and the ankle of middle-aged males. Many hypotheses have been proposed to explain the pathogenesis of the disease. Unfortunately, the etiology of BMES remains obscure. The hallmark that separates BMES from other conditions presented with BME pattern is its self-limited nature. Laboratory tests usually do not contribute to the diagnosis. Histological examination of the lesion is unnecessary. Plain radiographs may reveal regional osseous demineralization. Magnetic resonance imaging is mainly used for the early diagnosis and monitoring the progression of the disease. Early differentiation from other aggressive conditions with long-term sequelae is essential in order to avoid unnecessary treatment. Clinical entities, such as TOH, RMO, and RSD are spontaneously resolving, and surgical treatment is not needed. On the other hand, early differential diagnosis and surgical treatment in case of osteonecrosis is of crucial importance. (orig.)

  11. Chronic Alcohol Abuse Leads to Low Bone Mass with No General Loss of Bone Structure or Bone Mechanical Strength

    DEFF Research Database (Denmark)

    Ulhøi, Maiken Parm; Meldgaard, Karoline; Steiniche, Torben

    2017-01-01

    Chronic alcohol abuse (CAA) has deleterious effects on skeletal health. This study examined the impact of CAA on bone with regard to bone density, structure, and strength. Bone specimens from 42 individuals with CAA and 42 individuals without alcohol abuse were obtained at autopsy. Dual-energy X...... wall thickness of trabecular osteons compared to individuals without alcohol abuse. No significant difference was found for bone strength and structure. Conclusion: CAA leads to low bone mass due to a decrease in bone formation but with no destruction of bone architecture nor a decrease in bone...

  12. Bones, Muscles, and Joints: The Musculoskeletal System

    Science.gov (United States)

    ... Facts Dealing With Broken Bones Proximal Biceps Tendonitis Hamstring Strain Muscular Dystrophy Stress Fractures Scoliosis Juvenile Idiopathic Arthritis (JIA) Strains and Sprains Broken Bones Bones, Muscles, and Joints Achilles Tendonitis View more Partner Message ...

  13. Bone Mass Measurement: What the Numbers Mean

    Science.gov (United States)

    ... the Test Do? The T-Score World Health Organization Definitions Based on Bone Density Levels Low Bone Mass ... number, the more severe the osteoporosis. World Health Organization Definitions Based on Bone Density Levels Level Definition Normal ...

  14. Blood and Bone MarrowTransplant?

    Science.gov (United States)

    ... Topics / Blood and Bone Marrow Transplant Blood and Bone Marrow Transplant Also known as Hematopoietic Stem Cell Transplant , Hematopoietic Cell Transplant , Autologous Transplant , Allogeneic Transplant A blood or bone marrow ...

  15. Osteoporosis: Peak Bone Mass in Women

    Science.gov (United States)

    ... has been linked to low bone density in adolescents and is associated with other unhealthy behaviors, such ... Bone Health for Lupus Patients Bone Health and Anorexia Nervosa Partner Resources Screening Tests and Immunizations Guidelines for ...

  16. False air-bone gap.

    Science.gov (United States)

    Rudmin, F

    1983-01-01

    A single case is reported of a severely hearing-impaired child with a finding of a large air-bone gap on pure-tone audiometry on multiple tests. Exploratory surgery found normal middle ear function. Subsequent audiometry indicated the presence of a false air-bone gap resulting from vibrotactile responses. Test procedures for identifying vibrotactile responses are discussed.

  17. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... be more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, rotator cuff and labrum tears in the shoulder) and in imaging of the spine (because both the bones and the spinal cord can be evaluated). MRI can also detect subtle ...

  18. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... be more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, rotator cuff and labrum tears in the shoulder) and in imaging of the spine (because both the bones and the spinal cord can be evaluated). MRI can also detect ...

  19. Time Simulation of Bone Adaptation

    DEFF Research Database (Denmark)

    Bagge, Mette

    1998-01-01

    The structural adaptation of a three-dimensional finite element model ofthe proximal femur is considered. Presuming the bone possesses the optimalstructure under the given loads, the bone material distribution is foundby minimizing the strain energy averaged over ten load cases with avolume...

  20. Green Tea and Bone Metabolism

    Science.gov (United States)

    Osteoporosis is a major health problem in elderly men and women. Epidemiological evidence has shown association between tea consumption and age-related bone loss in elderly men and women. The aim of this review is to provide a systemic review of green tea and bone health to cover the following topi...

  1. Bone healing around nanocrystalline hydroxyapatite, deproteinized bovine bone mineral, biphasic calcium phosphate, and autogenous bone in mandibular bone defects

    DEFF Research Database (Denmark)

    Broggini, Nina; Bosshardt, Dieter D; Jensen, Simon S

    2015-01-01

    with nanocrystalline hydroxyapatite (HA-SiO), deproteinized bovine bone mineral (DBBM), biphasic calcium phosphate (BCP) with a 60/40% HA/β-TCP (BCP 60/40) ratio, or particulate autogenous bone (A) for histological and histomorphometric analysis. At 2 weeks, percent filler amongst the test groups (DBBM (35.65%), HA...

  2. Bone tissue engineering in osteoporosis.

    Science.gov (United States)

    Jakob, Franz; Ebert, Regina; Ignatius, Anita; Matsushita, Takashi; Watanabe, Yoshinobu; Groll, Juergen; Walles, Heike

    2013-06-01

    Osteoporosis is a polygenetic, environmentally modifiable disease, which precipitates into fragility fractures of vertebrae, hip and radius and also confers a high risk of fractures in accidents and trauma. Aging and the genetic molecular background of osteoporosis cause delayed healing and impair regeneration. The worldwide burden of disease is huge and steadily increasing while the average life expectancy is also on the rise. The clinical need for bone regeneration applications, systemic or in situ guided bone regeneration and bone tissue engineering, will increase and become a challenge for health care systems. Apart from in situ guided tissue regeneration classical ex vivo tissue engineering of bone has not yet reached the level of routine clinical application although a wealth of scaffolds and growth factors has been developed. Engineering of complex bone constructs in vitro requires scaffolds, growth and differentiation factors, precursor cells for angiogenesis and osteogenesis and suitable bioreactors in various combinations. The development of applications for ex vivo tissue engineering of bone faces technical challenges concerning rapid vascularization for the survival of constructs in vivo. Recent new ideas and developments in the fields of bone biology, materials science and bioreactor technology will enable us to develop standard operating procedures for ex vivo tissue engineering of bone in the near future. Once prototyped such applications will rapidly be tailored for compromised conditions like vitamin D and sex hormone deficiencies, cellular deficits and high production of regeneration inhibitors, as they are prevalent in osteoporosis and in higher age. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... An MRI may be more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, rotator cuff and labrum tears in the shoulder) and in imaging of the spine (because both the bones and the spinal cord can be evaluated). MRI ...

  4. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... views of bone, they provide little information about muscles, tendons or joints. An MRI may be more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, rotator cuff and labrum ...

  5. Roentgenologic bone changes in phenylketonuria

    International Nuclear Information System (INIS)

    Zhang Xuezhe; Shang Yanning; Yu Weimin; Li Yongfa; Wang Yongchun; Wang Wu

    2000-01-01

    Objective: To report the bone X-ray changes in phenylketonuria. Methods: Thirty-seven cases of phenylketonuria were reported. Among the 37 cases, 25 were males and 12 were females. The age of this series ranged from 6 months to 9 years. X-ray examination of the hands, wrists, and knees and laboratory examination were performed in all cases. Results: The bone changes of the 37 cases were divided into 6 groups: no abnormal findings, osteoporosis, metaphyseal changes, special changes, the bone age method, and miscellaneous changes. Special changes included striations into the diaphysis (12 cases) and beak of the metaphyseal margin (21 cases). Conclusion: The mechanism causing the bone changes in phenylketonuria is not quite clear. The authors conclude that specific bone changes may be important X-ray signs suggestive of phenylketonuria

  6. Ethnic Differences in Bone Health

    Directory of Open Access Journals (Sweden)

    Ayse eZengin

    2015-03-01

    Full Text Available There are differences in bone health between ethnic groups in both men and in women. Variations in body size and composition are likely to contribute to reported differences. Most studies report ethnic differences in areal bone mineral density (aBMD which do not consistently parallel ethnic patterns in fracture rates. This suggests that other parameters beside aBMD should be considered when determining fracture risk between and within populations, including other aspects of bone strength: bone structure and microarchitecture as well muscle strength (mass, force generation, anatomy and fat mass. We review what is known about differences in bone-densitometry derived outcomes between ethnic groups and the extent to which they account for the differences in fracture risk. Studies are included that were published primarily between 1994 – 2014. A ‘one size fits all approach’ should not be used to understand better ethnic differences in fracture risk.

  7. Radiodiagnosis of hemophiliac bone pseudotumors

    International Nuclear Information System (INIS)

    Fedorov, V.V.; Chantseva, E.A.

    1992-01-01

    Of 259 hemophiliacs bone pseudotumors were diagnosed in 11 (4.3 %); they were localised in the femur (6 cases), calcaneus (4) and in the iliac bone (3). Two cases of combined fermoral and calcaneal lesions and 4 cases of bone fracture were observed. As a rule, pseudotumors developed in hemophiliacs with severe disease. An x-ray picture of a pseudotumor depended on its site and was characterized by a large soft tissue tumor shadow, often with calcinosis, and serious destructive changes in bones in the form or round foci of 7 cm in diameter with clear-cut contours. An adge defect of the cortical layer was defined in the diaphysis of the femoral bone (15 cm long). Destructive changes were often accompanied by osteosclerosis and periostitis

  8. The healing of fractured bones

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Central Electricity Generating Board, Cheltenham (United Kingdom)

    1997-04-01

    A method utilising neutron beams of width 1 mm, used on D1B (2.4 A) and D20 (1.3 A) to study the healing of fractured bones is presented. It is found that the callus bone uniting the fractured tibia of a sheep, whose healing had been encouraged by daily mechanical vibration over a period of three months, showed no trace of the large preferential vertical orientation of the apatite crystals which is characteristic of the normal bone. Nevertheless the bone had regained about 60% of its mechanical strength and the callus bone, although not oriented, was well crystallized. It is considered that the new monochromator for D20, expected to give increased intensity at 2.5 A, will be of considerable advantage. (author). 2 refs.

  9. Ultrasonic Needles for Bone Biopsy.

    Science.gov (United States)

    Mathieson, Andrew; Wallace, Robert; Cleary, Rebecca; Li Li; Simpson, Hamish; Lucas, Margaret

    2017-02-01

    Bone biopsy is an invasive clinical procedure, where a bone sample is recovered for analysis during the diagnosis of a medical condition. When the architecture of the bone tissue is required to be preserved, a core-needle biopsy is taken. Although this procedure is performed while the patient is under local anaesthesia, the patient can still experience significant discomfort. Additionally, large haematoma can be induced in the soft tissue surrounding the biopsy site due to the large axial and rotational forces, which are applied through the needle to penetrate bone. It is well documented that power ultrasonic surgical devices offer the advantages of low cutting force, high accuracy, and preservation of soft tissues. This paper reports a study of the design, analysis, and test of two novel power ultrasonic needles for bone biopsy that operate using different configurations to penetrate bone. The first utilizes micrometric vibrations generated at the distil tip of a full-wavelength resonant ultrasonic device, while the second utilizes an ultrasonic-sonic approach, where vibrational energy generated by a resonant ultrasonic horn is transferred to a needle via the chaotic motion of a free-mass. It is shown that the dynamic behavior of the devices identified through experimental techniques closely match the behavior calculated through numerical and finite-element analysis methods, demonstrating that they are effective design tools for these devices. Both devices were able to recover trabecular bone from the metaphysis of an ovine femur, and the biopsy samples were found to be comparable to a sample extracted using a conventional biopsy needle. Furthermore, the resonant needle device was also able to extract a cortical bone sample from the central diaphysis, which is the strongest part of the bone, and the biopsy was found to be superior to the sample recovered by a conventional bone biopsy needle.

  10. Bone turnover in postmenopausal osteoporosis

    International Nuclear Information System (INIS)

    Thomsen, K.

    1988-02-01

    Studies of the bone turnover in postmenopausal osteoporosis are essential, because the associated bone loss is inevitably due to the relative increase of bone resorption compared with bone formation. Measurement of the bone mineral content (BMC) in normal adults is assessed - partly on the uncorrected values and partly in proportion to the body muscle mass. The whole body retention (WBR) method is presented. The WBR and alternative urinary excretion (UE) methods used by the author are characterised and compared with the retention methods described in the literature. The representativity of WBR and UE for the estimation of bone turnover in normal subjects and patients with various bone metabolic diseases is discussed. The conclusion is that the modified retention methods used by the author have a satisfactory precision and accuracy in relation to the clinical studies carried out. The author's modification of the WBR method for determination of bone turnover and the alternative urinary excretion method (UE) consists in continuous scanning in the whole body count, using a gamma camera, and with the collimator a short distance from the volunteer. This procedure has the advantage of restricting the radioactive dose to 2 mCi (72 MBa). This is smaller by a factor of 5-10 than the dose used to measure WBR with equally simple counting equipment: With the author's procedure, using frontal counting, WBR is systematically underestimated by about 4 per cent point compared to the purely dorsal count, but since the frontal position is the most comfortable, requires a smaller radioactive dose, and the error is systematic, it is the preferred counting procedure. Correction of WBR and UE for bone mineral content is in principle a new parameter of bone turnover, whose improved accuracy increases the validity of the retention determinations. 136 refs. (EG)

  11. Chronic Alcohol Abuse Leads to Low Bone Mass with No General Loss of Bone Structure or Bone Mechanical Strength.

    Science.gov (United States)

    Ulhøi, Maiken Parm; Meldgaard, Karoline; Steiniche, Torben; Odgaard, Anders; Vesterby, Annie

    2017-01-01

    Chronic alcohol abuse (CAA) has deleterious effects on skeletal health. This study examined the impact of CAA on bone with regard to bone density, structure, and strength. Bone specimens from 42 individuals with CAA and 42 individuals without alcohol abuse were obtained at autopsy. Dual-energy X-ray absorptiometry (DEXA), compression testing, ashing, and bone histomorphometry were performed. Individuals with CAA had significantly lower bone mineral density (BMD) in the femoral neck and significantly lower bone volume demonstrated by thinner trabeculae, decreased extent of osteoid surfaces, and lower mean wall thickness of trabecular osteons compared to individuals without alcohol abuse. No significant difference was found for bone strength and structure. CAA leads to low bone mass due to a decrease in bone formation but with no destruction of bone architecture nor a decrease in bone strength. It is questionable whether this per se increases fracture risk. © 2016 American Academy of Forensic Sciences.

  12. Histologic diagnosis of metabolic bone diseases: bone histomorphometry

    Directory of Open Access Journals (Sweden)

    L. Dalle Carbonare

    2011-09-01

    Full Text Available Histomorphometry or quantitative histology is the analysis on histologic sections of bone resorption parameters, formation and structure. It is the only technique that allows a dynamic evaluation of the activity of bone modelling after labelling with tetracycline. Moreover, the new measurement procedures through the use of the computer allow an assessment of bone microarchitecture too. Histomorphometric bone biopsy is a reliable and well-tolerated procedure. Complications are reported only in 1% of the subjects (hematoma, pain, transient neuralgia. Histomorphometry is used to exclude or confirm the diagnosis of osteomalacia. It is employed in the evaluation of bone damage associated with particular treatments (for example, anticonvulsants or in case of rare bone diseases (osteogenesis imperfecta, systemic mastocytosis. It is also an essential approach when clinical, biochemical and other diagnostic data are not consistent. Finally, it is a useful method to understand the pathophysiologic mechanisms of drugs. The bone sample is taken at the level of iliac crest under local anesthesia. It is then put into methyl-metacrilate resin where the sections are prepared for the microscopic analysis of the various histomorphometric parameters.

  13. Bone composition: relationship to bone fragility and antiosteoporotic drug effects.

    Science.gov (United States)

    Boskey, Adele L

    2013-01-01

    The composition of a bone can be described in terms of the mineral phase, hydroxyapatite, the organic phase, which consists of collagen type I, noncollagenous proteins, other components and water. The relative proportions of these various components vary with age, site, gender, disease and treatment. Any drug therapy could change the composition of a bone. This review, however, will only address those pharmaceuticals used to treat or prevent diseases of bone: fragility fractures in particular, and the way they can alter the composition. As bone is a heterogeneous tissue, its composition must be discussed in terms of the chemical makeup, properties of its chemical constituents and their distributions in the ever-changing bone matrix. Emphasis, in this review, is placed on changes in composition as a function of age and various diseases of bone, particularly osteoporosis. It is suggested that while some of the antiosteoporotic drugs can and do modify composition, their positive effects on bone strength may be balanced by negative ones.

  14. Progesterone and Bone: Actions Promoting Bone Health in Women

    Directory of Open Access Journals (Sweden)

    Vanadin Seifert-Klauss

    2010-01-01

    Full Text Available Estradiol (E2 and progesterone (P4 collaborate within bone remodelling on resorption (E2 and formation (P4. We integrate evidence that P4 may prevent and, with antiresorptives, treat women's osteoporosis. P4 stimulates osteoblast differentiation in vitro. Menarche (E2 and onset of ovulation (P4 both contribute to peak BMD. Meta-analysis of 5 studies confirms that regularly cycling premenopausal women lose bone mineral density (BMD related to subclinical ovulatory disturbances (SODs. Cyclic progestin prevents bone loss in healthy premenopausal women with amenorrhea or SOD. BMD loss is more rapid in perimenopause than postmenopause—decreased bone formation due to P4 deficiency contributes. In 4 placebo-controlled RCTs, BMD loss is not prevented by P4 in postmenopausal women with increased bone turnover. However, 5 studies of E2-MPA co-therapy show greater BMD increases versus E2 alone. P4 fracture data are lacking. P4 prevents bone loss in pre- and possibly perimenopausal women; progesterone co-therapy with antiresorptives may increase bone formation and BMD.

  15. Maxillary bone myxoma.

    Science.gov (United States)

    Zainine, R; Mizouni, H; El Korbi, A; Beltaief, N; Sahtout, S; Besbes, G

    2014-09-01

    Maxillary bone myxoma is a rare benign mesenchymal tumor, slow-growing but locally aggressive. Pathogenesis remains disputed. To study the clinical, radiological and histological features and treatment of maxillary myxoma, based on a pediatric case report. An infant of two and a half months presented with endonasal tumor extending to ethmoid. Surgical excision was performed on an endonasal approach. Myxoma was diagnosed by histologic examination of the surgical specimen, whereas initial biopsy had suggested fibrous dysplasia. No recurrence was observed after two and a half years' surveillance. Positive diagnosis of maxillary myxoma is histological. Treatment is primarily surgical. Strict long-term surveillance is required because of the high risk of recurrence. Copyright © 2013. Published by Elsevier Masson SAS.

  16. Bone position emission tomography with or without CT Is more accurate than bone scan for detection of bone metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo Jin; Lee, Wom Woo; Kim, Sang Eun [Dept. of Nuclear Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of)

    2013-06-15

    Na1{sup 8F} bone positron emission tomography (bone PET) is a new imaging modality which is useful for the evaluation of bone diseases. Here, we compared the diagnostic accuracies between bone PET and bone scan for the detection of bone metastasis (BM). Sixteen cancer patients (M:F = 10:6, mean age = 60 ± 12 years) who underwent both bone PET and bone scan were analyzed. Bone PET was conducted 30 minutes after the injection of 370 MBq Na1{sup 8F}, and a bone scan was performed 3 hours after the injection of 1295 MBq 9{sup 9mT}c-hydroxymethylene diphosphonate. In the patient-based analysis (8 patients with BM and 8 without BM), the sensitivities of bone PET (100% 8/8) and bone scan (87.5% = 7/8) were not significantly different (p > 0.05), whereas the specificity of bone PET (87.5% = 7/8) was significantly greater than that of the bone scan (25% = 2/8) (p < 0.05). In the lesion-based analysis (43 lesions in 14 patients; 31 malignant and 12 benign), the sensitivity of bone PET (100% = 31/31) was significantly greater than that of bone scan (38.7% = 12/31) (p < 0.01), and the specificity of bone PET (75.0% = 9/12) was also significantly higher than that of bone scan (8.3% = 1/12) (p < 0.05). The receiver operating characteristic curve analysis showed that bone PET was significantly more accurate than the bone scan in the patient (p = 0.0306) and lesion (p = 0.0001) based analyses. Na1{sup 8F} bone PET is more accurate than bone scan for BM evaluation.

  17. Bone pain palliation: Philippines setting

    International Nuclear Information System (INIS)

    Pagsisihan, J.R.; Barrenechea, E.; San Luis, T.O.L.

    2008-01-01

    Metastatic bone disease is a major sequela of several solid cancers; the breast, prostate, lung, kidney and thyroid etc. Bone pain is a common symptom in advancing malignancy and often determines the quality of life in the later stages of disease. Management of bone pain remains palliative at present. With the improved cancer survival resulting from advances in cancer management, the population of patients seeking relief of bone pain has increased. Radiopharmaceutical therapy offers potential pain relief with minimal adverse effects. The purpose of this study was to assess the current status of radiopharmaceutical therapy for bone pain palliation in the Philippines. To date, no study has been done on bone pain palliation therapy. The study population included all cancer patients with bone metastasis presenting with chronic bone pain who were subjected to radiopharmaceutical therapy for bone pain palliation in the different medical centers and hospitals in the Philippines. The clinical histories of the patients were reviewed. The specific radiopharmaceutical and corresponding doses used for the said therapies were also noted. The respondents were inquired of the effectiveness of the therapy in relieving bone pain and duration of the response to the therapy. The complete blood count, before and after the therapy, were retrieved. The approximate cost of the therapy was also inquired and was then compared with the cost of different treatment modalities. Over the years only six radiopharmaceutical therapies have been performed in the Philippines (three male patients with prostate cancer, two female patients with breast cancer and one female patient with renal cancer). All had multiple bone metastases on bone scintigraphy and presented with chronic bone pain, which were not adequately controlled by other treatment modalities such as analgesics, bisphosphonates, chemotherapy, hormonal therapy and radiation therapy. Four subjects were subjected to Strontium-89 chloride (Sr

  18. Improved repair of bone defects with prevascularized tissue-engineered bones constructed in a perfusion bioreactor.

    Science.gov (United States)

    Li, De-Qiang; Li, Ming; Liu, Pei-Lai; Zhang, Yuan-Kai; Lu, Jian-Xi; Li, Jian-Min

    2014-10-01

    Vascularization of tissue-engineered bones is critical to achieving satisfactory repair of bone defects. The authors investigated the use of prevascularized tissue-engineered bone for repairing bone defects. The new bone was greater in the prevascularized group than in the non-vascularized group, indicating that prevascularized tissue-engineered bone improves the repair of bone defects. [Orthopedics. 2014; 37(10):685-690.]. Copyright 2014, SLACK Incorporated.

  19. Allogenic bone grafts in post-traumatic juxta-articular defects: Need for allogenic bone banking.

    Science.gov (United States)

    Mishra, Anil Kumar; Vikas, Rohit; Agrawal, H S

    2017-07-01

    Allogenic bone banking provide both structural and granular bone grafts for various orthopaedic, spinal, oncological and dental surgeries. However allogenic bones, presently, are not readily available. This article discusses the clinical applications of the allogenic grafts, the screening criteria and procedure for maintenance of such a bone banking facility. This article demonstrates the effective role of allogenic bone in a case of post-traumatic bone loss situation and discusses the growing need and present situation of bone banking in our country.

  20. Re-evaluation of bone pain in patients with type 1 Gaucher disease suggests that bone crises occur in small bones as well as long bones.

    Science.gov (United States)

    Baris, Hagit N; Weisz Hubshman, Monika; Bar-Sever, Zvi; Kornreich, Liora; Shkalim Zemer, Vered; Cohen, Ian J

    2016-09-01

    Bone crises in type 1 Gaucher disease are reported in long bones and occasionally in weight bearing bones and other bones, but rarely in small bones of the hands and feet. We retrospectively examined the incidence of bone pain in patients followed at the Rabin Medical Center, Israel, before and following the initiation of enzyme replacement therapy (ERT) and evaluated them for bone crises. Of 100 type I Gaucher disease patients, 30 (30%) experienced one or more bone crises. Small bone crises represented 31.5% of all bone crises and were always preceded by crises in other bones. While the incidence of long bone crises reduced after the initiation of ERT, small bone crises increased. Almost 60% of patients with bone crises were of the N370S/84GG genotype suggesting a greater susceptibility of N370S/84GG patients to severe bone complications. These patients also underwent the greatest number of splenectomies (70.6% of splenectomised patients). Splenectomised patients showed a trend towards increased long and small bone crises after surgery. Active investigation of acute pain in the hands and feet in patients in our cohort has revealed a high incidence of small bone crises. Physicians should consider imaging studies to investigate unexplained pain in these areas. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Bone health in anorexia nervosa

    Science.gov (United States)

    Misra, Madhusmita; Klibanski, Anne

    2013-01-01

    Purpose of review Anorexia nervosa is associated with low bone mineral density (BMD), concerning for an increased risk of fractures, and decreased bone accrual in adolescents, concerning for suboptimal peak bone mass. This review discusses causes of impaired bone health in anorexia nervosa and potential therapeutic strategies. Recent findings Low BMD in anorexia nervosa is consequent to decreased lean mass, hypogonadism, low insulin-like growth factor-1 (IGF-1), relative hypercortisolemia and alterations in hormones impacted by energy availability. Weight gain causes some improvement in bone accrual, but not to the extent observed in controls, and vitamin D supplementation does not increase BMD. Oral estrogen is not effective in increasing BMD, likely from IGF-1 suppressive effects. In contrast, transdermal estrogen replacement is effective in increasing bone accrual in adolescents with anorexia nervosa, although not to the extent seen in controls. Recombinant human IGF-1 increases bone formation in adolescents, and with oral estrogen increases BMD in adults with anorexia nervosa. Bisphosphonates increase BMD in adults, but not in adolescents, and should be used cautiously given their long half-life. Summary Further investigation is necessary to explore therapies for low BMD in anorexia nervosa. Weight gain is to be encouraged. Transdermal estrogen in adolescents, and bisphosphonates in adults, have a potential therapeutic role. PMID:21897220

  2. Today's understanding about bone aging.

    Science.gov (United States)

    Grzibovskis, Maris; Pilmane, Mara; Urtane, Ilga

    2010-01-01

    Patient's age is an important factor in orthodontic treatment. There are many studies about bone aging from the aspects of osteoporosis and other bone diseases. Both, aging and osteoporosis are associated problems and have a great importance in relation to their incidence. But not only osteoporosis or other bone related diseases are issue for many studies, because the knowledge of bone pathophysiology and diagnostics with signaling molecules makes it possible to predict treatment outcome and specific cell targeted pharmacology. In recent years immunohistological studies had become very popular in all fields of medicine including orthodontics, too. The question we tried to answer in this literature mini-review was--what kind of immunohistological studies were done from the aspect of bone aging in relation to patient`s age and orthodontic treatment? Search on Cochrane Library, PubMed, Science Direct, and DynaMed data bases by keywords: Alveolar bone aging, RANK, RANKL, OPG, MMP-1, MMP-8, IL-1, IL-6, TNF-α, TNF-β, and BM, resulted with 147 full-text articles; from them 90 met the criteria, 30 were reviews, and only in 22 articles from 60 bone aging from the aspect of signaling molecules were discussed. Interestingly, only 2 articles (Cei 2006 and Zhang 2003) were related to alveolar bone, and none studied it from the orthodontic point of view. Patient`s age plays an important role in orthodontic treatment, because of the bone response to mechanical loading. It is in accordance to clinical studies, or alike, that tooth movement in younger patient occurs much faster than in adults, but the question which factors are responsible for the process still remains.

  3. Bone position emission tomography with or without CT Is more accurate than bone scan for detection of bone metastasis

    International Nuclear Information System (INIS)

    Lee, Soo Jin; Lee, Wom Woo; Kim, Sang Eun

    2013-01-01

    Na1 8F bone positron emission tomography (bone PET) is a new imaging modality which is useful for the evaluation of bone diseases. Here, we compared the diagnostic accuracies between bone PET and bone scan for the detection of bone metastasis (BM). Sixteen cancer patients (M:F = 10:6, mean age = 60 ± 12 years) who underwent both bone PET and bone scan were analyzed. Bone PET was conducted 30 minutes after the injection of 370 MBq Na1 8F , and a bone scan was performed 3 hours after the injection of 1295 MBq 9 9mT c-hydroxymethylene diphosphonate. In the patient-based analysis (8 patients with BM and 8 without BM), the sensitivities of bone PET (100% 8/8) and bone scan (87.5% = 7/8) were not significantly different (p > 0.05), whereas the specificity of bone PET (87.5% = 7/8) was significantly greater than that of the bone scan (25% = 2/8) (p 8F bone PET is more accurate than bone scan for BM evaluation.

  4. Myxoma of the nasal bone.

    Science.gov (United States)

    Al-Qahtani, Khalid; Islam, Tahera; AlOulah, Mohammad; Bafaqeeh, Sameer; Faqeeh, Yasser

    2017-06-01

    Myxoma is a benign tumor that arises from mesenchymal tissue, and found in the soft tissue and less commonly in the bone. The majority of bony myxomas of the head and neck occur in the jaws and maxilla. We report an extremely rare case of nasal bone myxoma in a 52-year-old man. The diagnosis was confirmed by biopsy. Due to the aggressive nature of the lesion the nasal bone was eroded by the disease. The patient underwent resection of the mass with reconstruction of the defect by septal cartilage. The patient remains tumor free after 5 years. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Bone markers in craniofacial bone deformations and dysplasias

    Directory of Open Access Journals (Sweden)

    Monika Seifert

    2015-10-01

    Full Text Available Various forms of bony deformations and dysplasias are often present in the facial skeleton. Bone defects can be either localized or general. Quite often they are not only present in the skull but also can be found in other parts of the skeleton. In many cases the presence and levels of specific bone markers should be measured in order to fully describe their activity and presence in the skeleton. Fibrous dysplasia (FD is the most common one in the facial skeleton; however, other bone deformations regarding bone growth and activity can also be present. Every clinician should be aware of all common, rare and uncommon bony diseases and conditions such as cherubism, Paget’s disease, osteogenesis imperfecta and others related to genetic conditions. We present standard (calcium, parathyroid hormone, calcitonin, alkaline phosphatase, vitamin D and specialized bone markers (pyridinium, deoxypyridinium, hydroxyproline, RANKL/RANK/OPG pathway, growth hormone, insulin-like growth hormone-1 that can be used to evaluate, measure or describe the processes occurring in craniofacial bones.

  6. Radiopharmaceuticals for bone and bone-marrow imaging

    International Nuclear Information System (INIS)

    Subramanian, G.; McAfee, J.G.; Blair, R.J.; Thomas, F.D.

    1977-01-01

    The review discusses the current status of available radiopharmaceuticals for bone and bone-marrow imaging. For skeletal imaging 99 Tcsup(m)-labelled diphosphonates as a group seem to be superior to other phosphorous compounds including pyrophosphate. Of the diphosphonates, 99 Tcsup(m)-labelled MDP is better than EHDP. The new compound 99 Tcsup(m)-IDP shows more skeletal uptake than MDP or EHDP in patients, but requires further clinical evaluation. Bone-marrow imaging has not received as much attention as bone imaging because of the lack of suitable radiopharmaceuticals. The erythropoietic marrow can be well visualized by using iron-52, an accelerator-produced positron emitter (511 keV gamma). However, availability (short half-life) and instrumentation problems limit its use to only a few institutions with access to an accelerator. The RES cell function of the bone marrow can be demonstrated by using colloids labelled with a suitable radionuclide. However, none of the available colloids of short-lived radionuclides ( 99 Tcsup(m) or 113 Insup(m)) localize to any great extent in the marrow - their localization often being limited to 10-15% of the injected dose in normal patients. Indium-111 chloride has been claimed to be useful as an erythropoietic cell marrow imaging agent by some investigators but others have disputed this claim. At the present time, we do not have an optimal agent for bone-marrow imaging and further work in this area is warranted. (author)

  7. ALVEOLAR BONE REGENERATION AFTER DEMINERALIZED FREEZE DRIED BONE ALOGRAFT (DFDBA BONE GRAFTING

    Directory of Open Access Journals (Sweden)

    Sri Oktawati

    2006-04-01

    Full Text Available Periodontal treatment by conventional way will result in healing repair, which easily cause recurrence. Modification of treatment should be done to get an effective result, that is the regeneration of alveolar bone and to reduce inflammation. The objective of this study is to determine the alveolar bone regeneration after using DFDBA (Demineralized Freeze Dried Bone Allograft. Quasi experimental designs with pre and post test method was used in this study. From 13 patients, 26 defects got conventional or regenerative treatment. The indicator of alveolar bone regenaration in bone height in radiographic appearance and level of osteocalsin in gingival crevicular fluid (GCF were checked before and after the treatment, then the changes that occurred were analyzed. The result of the research showed that alveolar bone regeneration only occurred to the group of regenerative treatment using DFDBA. The conclusion is the effective periodontal tissue regeneration occurred at regenerative treatment by using DFDBA, and the osteocalsin in GCF can be used as indicator of bone growth.

  8. Bone intake by vultures in Namibia

    African Journals Online (AJOL)

    2007-09-01

    Sep 1, 2007 ... onwards (taken as the beginning of the breeding period). A rough estimate of bone ... associated with horses (Mönnig &. Veldman 1989) .... period (g). Mean mass of bones consumed per visiting vulture (g). Mean mass of bones per bone- consuming vulture. Non-breeding season. 700. 466. 225. 1.65. 49.4.

  9. Bone metabolism in patients with rheumatoid arthritis

    NARCIS (Netherlands)

    Bijlsma, J. W.

    1988-01-01

    Bone metabolism in patients with rheumatoid arthritis is reviewed. Two different entities are recognised: 1) a localised periarticular bone loss, due to inflammatory processes and 2) a generalised increased bone turnover, ultimately leading to a loss of axial bone mass. The mechanism of this loss of

  10. Bone X-Ray (Radiography)

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    Full Text Available ... for your doctor to view and assess bone fractures, injuries and joint abnormalities. This exam requires little ... stabilization of bony fragments following treatment of a fracture. guide orthopedic surgery, such as spine repair/fusion, ...

  11. Bone X-Ray (Radiography)

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    Full Text Available ... taken of the unaffected limb, or of a child's growth plate (where new bone is forming), for ... around joints, and in evaluating the hips of children with congenital problems. top of page This page ...

  12. Bone X-Ray (Radiography)

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    Full Text Available ... injury, infection, arthritis , abnormal bone growths and bony changes seen in metabolic conditions. assist in the detection ... examination may also be necessary so that any change in a known abnormality can be monitored over ...

  13. Bone X-Ray (Radiography)

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    Full Text Available ... of the radiation while soft tissue, such as muscle, fat and organs, allow more of the x- ... views of bone, they provide little information about muscles, tendons or joints. An MRI may be more ...

  14. Bone X-Ray (Radiography)

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    Full Text Available ... view and assess bone fractures, injuries and joint abnormalities. This exam requires little to no special preparation. ... follow-up exam is done because a potential abnormality needs further evaluation with additional views or a ...

  15. Bone X-Ray (Radiography)

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    Full Text Available ... bone in the body, including the hand, wrist, arm, elbow, shoulder, spine, pelvis, hip, thigh, knee, leg ( ... x-ray tube is connected to a flexible arm that is extended over the patient while an ...

  16. Bone X-Ray (Radiography)

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    Full Text Available ... to X-ray (Radiography) - Bone Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  17. Bone X-Ray (Radiography)

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    Full Text Available ... taken of the unaffected limb, or of a child's growth plate (where new bone is forming), for ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose ...

  18. Bone X-Ray (Radiography)

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    Full Text Available ... may also be asked to remove jewelry, removable dental appliances, eye glasses and any metal objects or ... for a physician to view and assess bone injuries, including fractures, and joint abnormalities, such as arthritis. ...

  19. Bone X-Ray (Radiography)

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits Bone x-rays are the fastest and ... in the typical diagnostic range for this exam. Risks There is always a slight chance of cancer ...

  20. Bone X-Ray (Radiography)

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    Full Text Available ... will analyze the images and send a signed report to your primary care or referring physician , who ... Medicine Radiation Safety How to Read Your Radiology Report Images related to X-ray (Radiography) - Bone Sponsored ...

  1. [Trace elements of bone tumors].

    Science.gov (United States)

    Kalashnikov, V M; Zaĭchik, V E; Bizer, V A

    1983-01-01

    Due to activation analysis involving the use of neutrons from a nuclear reactor, the concentrations of 11 trace elements: scandium, iron, cobalt, mercury, rubidium, selenium, silver, antimony, chrome, zinc and terbium in intact bone and skeletal tumors were measured. 76 specimens of bioptates and resected material of operations for bone tumors and 10 specimens of normal bone tissue obtained in autopsies of cases of sudden death were examined. The concentrations of trace elements and their dispersion patterns in tumor tissue were found to be significantly higher than those in normal bone tissue. Also, the concentrations of some trace elements in tumor differed significantly from those in normal tissue; moreover, they were found to depend on the type and histogenesis of the neoplasm.

  2. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... as spine repair/fusion, joint replacement and fracture reductions. look for injury, infection, arthritis , abnormal bone growths ... the individual patient's condition. Ultrasound imaging, which uses sound waves instead of ionizing radiation to create diagnostic ...

  3. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... x-ray uses a very small dose of ionizing radiation to produce pictures of any bone in the ... of the body to a small dose of ionizing radiation to produce pictures of the inside of the ...

  4. Flavonoid intake and bone health.

    Science.gov (United States)

    Weaver, Connie M; Alekel, D Lee; Ward, Wendy E; Ronis, Martin J

    2012-01-01

    Flavonoids, found in a wide diversity of plant foods from fruits and vegetables, herbs and spices, essential oils, and beverages, have the most potential of dietary components for promotion of bone health beyond calcium and vitamin D. Recent epidemiological studies show flavonoid consumption to have a stronger association with bone than general fruit and vegetable consumption. Bioactive flavonoids are being assessed for properties beyond their chemical antioxidant capacity, including anti-inflammatory actions. Some have been reported to enhance bone formation and to inhibit bone resorption through their action on cell signaling pathways that influence osteoblast and osteoclast differentiation. Future research is needed to determine which of the flavonoids and their metabolites are most effective and at what dose, as well as the mechanism of modulating cellular events, in order to set priorities for clinical trials.

  5. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... abnormalities. This exam requires little to no special preparation. Tell your doctor and the technologist if there ... prepare? Most bone x-rays require no special preparation. You will be asked to remove some of ...

  6. Bone X-Ray (Radiography)

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    Full Text Available ... in metabolic conditions. assist in the detection and diagnosis of bone cancer . locate foreign objects in soft ... frequently compared to current x-ray images for diagnosis and disease management. top of page How is ...

  7. Effects of radiation on bone.

    Science.gov (United States)

    Pacheco, Rafael; Stock, Harlan

    2013-12-01

    Ionizing radiation produces its deleterious biologic effects by both direct (DNA strand breaks) and indirect processes (formation of free oxygen radicals). Mitotically active cells are more susceptible to the detrimental effects of ionizing radiation. These effects are most severe locally within the treatment field but can also occur systemically, possibly reflecting hormonal influences and inflammatory cytokine mediators. Specific bone complications of radiation include osteopenia, growth arrest, fracture and malignancy. Some of these complications, such as osteopenia, are reversible and severity is dose dependent. Insufficiency fractures are a common complication after radiation therapy and generally affect those bones under most physiologic stress and with the highest ratio of trabecular to cortical bone. Familiarity with the radiographic appearance of irradiated bone, including computed tomography (CT) and magnetic resonance imaging (MRI), will improve image interpretation and facilitate accurate diagnosis.

  8. Bone X-Ray (Radiography)

    Medline Plus

    Full Text Available ... of page What will I experience during and after the procedure? A bone x-ray examination itself ... available in emergency rooms, physician offices, ambulatory care centers, nursing homes and other locations, making it convenient ...

  9. Drugs Approved for Bone Cancer

    Science.gov (United States)

    This page lists cancer drugs approved by the Food and Drug Administration (FDA) for bone cancer. The list includes generic names and brand names. The drug names link to NCI's Cancer Drug Information summaries.

  10. Bone X-Ray (Radiography)

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    Full Text Available ... patient. top of page How does the procedure work? X-rays are a form of radiation like ... taken of the unaffected limb, or of a child's growth plate (where new bone is forming), for ...

  11. Bone X-Ray (Radiography)

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    Full Text Available ... limb, or of a child's growth plate (where new bone is forming), for comparison purposes. When the ... Exams Arthritis X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety How to Read Your Radiology Report ...

  12. Bone X-Ray (Radiography)

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    Full Text Available ... limb, or of a child's growth plate (where new bone is forming), for comparison purposes. When the ... From (your name): Your e-mail address: Personal message (optional): Bees: Wax: Notice: RadiologyInfo respects your privacy. ...

  13. Understanding the Structure of Bones

    Science.gov (United States)

    ... structure of bone is very similar to reinforced concrete that is used to make a building or ... a defective blueprint is produced that tells the cell to produce deformed collagen, resulting in bad collagen ...

  14. Bone X-Ray (Radiography)

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    Full Text Available ... standards used by radiology professionals. Modern x-ray systems have very controlled x-ray beams and dose ... Medicine Radiation Safety How to Read Your Radiology Report Images related to X-ray (Radiography) - Bone Sponsored ...

  15. Treatment of Temporal Bone Fractures

    Science.gov (United States)

    Diaz, Rodney C.; Cervenka, Brian; Brodie, Hilary A.

    2016-01-01

    Traumatic injury to the temporal bone can lead to significant morbidity or mortality and knowledge of the pertinent anatomy, pathophysiology of injury, and appropriate management strategies is critical for successful recovery and rehabilitation of such injured patients. Most temporal bone fractures are caused by motor vehicle accidents. Temporal bone fractures are best classified as either otic capsule sparing or otic capsule disrupting-type fractures, as such classification correlates well with risk of concomitant functional complications. The most common complications of temporal bone fractures are facial nerve injury, cerebrospinal fluid (CSF) leak, and hearing loss. Assessment of facial nerve function as soon as possible following injury greatly facilitates clinical decision making. Use of prophylactic antibiotics in the setting of CSF leak is controversial; however, following critical analysis and interpretation of the existing classic and contemporary literature, we believe its use is absolutely warranted. PMID:27648399

  16. Bone X-Ray (Radiography)

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    Full Text Available ... more useful in identifying bone and joint injuries (e.g., meniscal and ligament tears in the knee, ... or suggestion into the following text box: Comment: E-mail: Area code: Phone no: Thank you! Please ...

  17. Bone X-Ray (Radiography)

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    Full Text Available ... assist in the detection and diagnosis of bone cancer . locate foreign objects in soft tissues around or ... Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  18. Bone X-Ray (Radiography)

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    Full Text Available ... 10 minutes. top of page What will I experience during and after the procedure? A bone x- ... examination itself is a painless procedure. You may experience discomfort from the cool temperature in the examination ...

  19. Paget disease of the bone

    Science.gov (United States)

    ... also affect the results of the following tests: Alkaline phosphatase (ALP) , bone specific isoenzyme Serum calcium Treatment ... Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. ...

  20. Digital Astronaut: Bone Remodeling Model

    Data.gov (United States)

    National Aeronautics and Space Administration — Significant progress has been made with regard to the plan outlined in the 2014 report for building in the effects of exercise induced loading on preserving bone...