WorldWideScience

Sample records for bone heterogeneity effects

  1. Posttranslational heterogeneity of bone alkaline phosphatase in metabolic bone disease.

    Science.gov (United States)

    Langlois, M R; Delanghe, J R; Kaufman, J M; De Buyzere, M L; Van Hoecke, M J; Leroux-Roels, G G

    1994-09-01

    Bone alkaline phosphatase is a marker of osteoblast activity. In order to study the posttranscriptional modification (glycosylation) of bone alkaline phosphatase in bone disease, we investigated the relationship between mass and catalytic activity of bone alkaline phosphatase in patients with osteoporosis and hyperthyroidism. Serum bone alkaline phosphatase activity was measured after lectin precipitation using the Iso-ALP test kit. Mass concentration of bone alkaline phosphatase was determined with an immunoradiometric assay (Tandem-R Ostase). In general, serum bone alkaline phosphatase mass and activity concentration correlated well. The activity : mass ratio of bone alkaline phosphatase was low in hyperthyroidism. Activation energy of the reaction catalysed by bone alkaline phosphatase was high in osteoporosis and in hyperthyroidism. Experiments with neuraminidase digestion further demonstrated that the thermodynamic heterogeneity of bone alkaline phosphatase can be explained by a different glycosylation of the enzyme.

  2. Heterogeneous Economic Integration Agreement Effects

    OpenAIRE

    Baier, Scott L.; Bergstrand, Jeffrey H.; Clance, Matthew W.

    2015-01-01

    Gravity equations have been used for more than 50 years to estimate ex post the partial effects of trade costs on international trade flows, and the well-known - and traditionally presumed exogenous – "trade-cost elasticity" plays a central role in computing general equilibrium trade-flow and welfare effects of trade-cost changes. This paper addresses theoretically and empirically the influence of variable and fixed export costs in explaining the likely heterogeneity in the trade-cost elast...

  3. Comparison of dose calculation algorithms in slab phantoms with cortical bone equivalent heterogeneities

    International Nuclear Information System (INIS)

    Carrasco, P.; Jornet, N.; Duch, M. A.; Panettieri, V.; Weber, L.; Eudaldo, T.; Ginjaume, M.; Ribas, M.

    2007-01-01

    To evaluate the dose values predicted by several calculation algorithms in two treatment planning systems, Monte Carlo (MC) simulations and measurements by means of various detectors were performed in heterogeneous layer phantoms with water- and bone-equivalent materials. Percentage depth doses (PDDs) were measured with thermoluminescent dosimeters (TLDs), metal-oxide semiconductor field-effect transistors (MOSFETs), plane parallel and cylindrical ionization chambers, and beam profiles with films. The MC code used for the simulations was the PENELOPE code. Three different field sizes (10x10, 5x5, and 2x2 cm 2 ) were studied in two phantom configurations and a bone equivalent material. These two phantom configurations contained heterogeneities of 5 and 2 cm of bone, respectively. We analyzed the performance of four correction-based algorithms and one based on convolution superposition. The correction-based algorithms were the Batho, the Modified Batho, the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system (TPS), and the Helax-TMS Pencil Beam from the Helax-TMS (Nucletron) TPS. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. All the correction-based calculation algorithms underestimated the dose inside the bone-equivalent material for 18 MV compared to MC simulations. The maximum underestimation, in terms of root-mean-square (RMS), was about 15% for the Helax-TMS Pencil Beam (Helax-TMS PB) for a 2x2 cm 2 field inside the bone-equivalent material. In contrast, the Collapsed Cone algorithm yielded values around 3%. A more complex behavior was found for 6 MV where the Collapsed Cone performed less well, overestimating the dose inside the heterogeneity in 3%-5%. The rebuildup in the interface bone-water and the penumbra shrinking in high-density media were not predicted by any of the calculation algorithms except the Collapsed Cone, and only the MC simulations matched the experimental values within

  4. Comparison of dose calculation algorithms in slab phantoms with cortical bone equivalent heterogeneities.

    Science.gov (United States)

    Carrasco, P; Jornet, N; Duch, M A; Panettieri, V; Weber, L; Eudaldo, T; Ginjaume, M; Ribas, M

    2007-08-01

    To evaluate the dose values predicted by several calculation algorithms in two treatment planning systems, Monte Carlo (MC) simulations and measurements by means of various detectors were performed in heterogeneous layer phantoms with water- and bone-equivalent materials. Percentage depth doses (PDDs) were measured with thermoluminescent dosimeters (TLDs), metal-oxide semiconductor field-effect transistors (MOSFETs), plane parallel and cylindrical ionization chambers, and beam profiles with films. The MC code used for the simulations was the PENELOPE code. Three different field sizes (10 x 10, 5 x 5, and 2 x 2 cm2) were studied in two phantom configurations and a bone equivalent material. These two phantom configurations contained heterogeneities of 5 and 2 cm of bone, respectively. We analyzed the performance of four correction-based algorithms and one based on convolution superposition. The correction-based algorithms were the Batho, the Modified Batho, the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system (TPS), and the Helax-TMS Pencil Beam from the Helax-TMS (Nucletron) TPS. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. All the correction-based calculation algorithms underestimated the dose inside the bone-equivalent material for 18 MV compared to MC simulations. The maximum underestimation, in terms of root-mean-square (RMS), was about 15% for the Helax-TMS Pencil Beam (Helax-TMS PB) for a 2 x 2 cm2 field inside the bone-equivalent material. In contrast, the Collapsed Cone algorithm yielded values around 3%. A more complex behavior was found for 6 MV where the Collapsed Cone performed less well, overestimating the dose inside the heterogeneity in 3%-5%. The rebuildup in the interface bone-water and the penumbra shrinking in high-density media were not predicted by any of the calculation algorithms except the Collapsed Cone, and only the MC simulations matched the experimental values

  5. Heterogeneity effects in neutron transport computations

    International Nuclear Information System (INIS)

    Gelbard, E.M.

    1975-01-01

    A nuclear reactor is, generally, an intricate heterogeneous structure whose adjacent components may differ radically in their neutronic properties. The heterogeneities in the structure of the reactor complicate the work of the reactor analyst and tend to degrade the efficiency of the numerical methods used in reactor computations. Two types of heterogeneity effects are considered. First, certain singularities in the solution of the neutron transport equation, induced by heterogeneities, are briefly described. Second, the effect of heterogeneities on neutron leakage rates, and consequently on effective diffusion coefficients, are discussed. (5 figures) (U.S.)

  6. Heterogeneous pattern of bone disease in adult type 1 Gaucher disease: clinical and pathological correlates.

    Science.gov (United States)

    van Dussen, L; Lips, P; van Essen, H W; Hollak, C E M; Bravenboer, N

    2014-09-01

    Gaucher disease (GD) is a lysosomal storage disorder characterized by accumulation of glucosylceramide in macrophages, so-called Gaucher cells, as a result of a deficiency of the lysosomal enzyme glucocerebrosidase. Bone complications are an important cause of morbidity of GD and are thought to result from imbalance in bone remodeling. Bone manifestations among GD patients demonstrate a large variation including increased osteoclastic bone resorption, low bone formation and osteonecrosis. The purpose of the current case series is to describe the histological features observed in undecalcified bone samples, obtained from three GD patients, and evaluate the relationship with clinical features in these patients. Bone fragments were obtained from three adult type 1 GD patients with variable degrees of bone disease during orthopedic surgery. Specimens were embedded without prior decalcification in methylmethacrylate and prepared for histology according to standardized laboratory procedures. Histology revealed a heterogeneous pattern of bone involvement. High cellularity of bone marrow, abundant presence of Gaucher cells (GCs) and high turnover were observed in a patient with a history of multiple bone complications, while minimal bone turnover and few GCs were detected in the mildest affected patient in this series. An intermediate picture with relatively low bone turnover and a substantial amount of Gaucher cells was demonstrated in the third, moderately affected patient. No gross abnormalities in three biochemical markers of bone turnover (osteocalcin, N-terminal propeptide of type 1 procollagen and type 1 collagen C-terminal telopeptide) were noted. Plastic embedding and subsequent Goldner and TRAP staining offered a unique possibility to study bone histological findings in GD. Our data show that bone manifestations in GD may vary both clinically as well as histologically and bone disease in GD will likely require a personalized approach. Copyright © 2014 Elsevier

  7. Heterogeneous Causal Effects and Sample Selection Bias

    DEFF Research Database (Denmark)

    Breen, Richard; Choi, Seongsoo; Holm, Anders

    2015-01-01

    The role of education in the process of socioeconomic attainment is a topic of long standing interest to sociologists and economists. Recently there has been growing interest not only in estimating the average causal effect of education on outcomes such as earnings, but also in estimating how...... causal effects might vary over individuals or groups. In this paper we point out one of the under-appreciated hazards of seeking to estimate heterogeneous causal effects: conventional selection bias (that is, selection on baseline differences) can easily be mistaken for heterogeneity of causal effects....... This might lead us to find heterogeneous effects when the true effect is homogenous, or to wrongly estimate not only the magnitude but also the sign of heterogeneous effects. We apply a test for the robustness of heterogeneous causal effects in the face of varying degrees and patterns of selection bias...

  8. Concerted effects of heterogeneous nuclear ribonucleoprotein C1/C2 to control vitamin D-directed gene transcription and RNA splicing in human bone cells.

    Science.gov (United States)

    Zhou, Rui; Park, Juw Won; Chun, Rene F; Lisse, Thomas S; Garcia, Alejandro J; Zavala, Kathryn; Sea, Jessica L; Lu, Zhi-Xiang; Xu, Jianzhong; Adams, John S; Xing, Yi; Hewison, Martin

    2017-01-25

    Traditionally recognized as an RNA splicing regulator, heterogeneous nuclear ribonucleoprotein C1/C2 (hnRNPC1/C2) can also bind to double-stranded DNA and function in trans as a vitamin D response element (VDRE)-binding protein. As such, hnRNPC1/C2 may couple transcription induced by the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH) 2 D) with subsequent RNA splicing. In MG63 osteoblastic cells, increased expression of the 1,25(OH) 2 D target gene CYP24A1 involved immunoprecipitation of hnRNPC1/C2 with CYP24A1 chromatin and RNA. Knockdown of hnRNPC1/C2 suppressed expression of CYP24A1, but also increased expression of an exon 10-skipped CYP24A1 splice variant; in a minigene model the latter was attenuated by a functional VDRE in the CYP24A1 promoter. In genome-wide analyses, knockdown of hnRNPC1/C2 resulted in 3500 differentially expressed genes and 2232 differentially spliced genes, with significant commonality between groups. 1,25(OH) 2 D induced 324 differentially expressed genes, with 187 also observed following hnRNPC1/C2 knockdown, and a further 168 unique to hnRNPC1/C2 knockdown. However, 1,25(OH) 2 D induced only 10 differentially spliced genes, with no overlap with differentially expressed genes. These data indicate that hnRNPC1/C2 binds to both DNA and RNA and influences both gene expression and RNA splicing, but these actions do not appear to be linked through 1,25(OH) 2 D-mediated induction of transcription. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. Material heterogeneity in cancellous bone promotes deformation recovery after mechanical failure.

    Science.gov (United States)

    Torres, Ashley M; Matheny, Jonathan B; Keaveny, Tony M; Taylor, David; Rimnac, Clare M; Hernandez, Christopher J

    2016-03-15

    Many natural structures use a foam core and solid outer shell to achieve high strength and stiffness with relatively small amounts of mass. Biological foams, however, must also resist crack growth. The process of crack propagation within the struts of a foam is not well understood and is complicated by the foam microstructure. We demonstrate that in cancellous bone, the foam-like component of whole bones, damage propagation during cyclic loading is dictated not by local tissue stresses but by heterogeneity of material properties associated with increased ductility of strut surfaces. The increase in surface ductility is unexpected because it is the opposite pattern generated by surface treatments to increase fatigue life in man-made materials, which often result in reduced surface ductility. We show that the more ductile surfaces of cancellous bone are a result of reduced accumulation of advanced glycation end products compared with the strut interior. Damage is therefore likely to accumulate in strut centers making cancellous bone more tolerant of stress concentrations at strut surfaces. Hence, the structure is able to recover more deformation after failure and return to a closer approximation of its original shape. Increased recovery of deformation is a passive mechanism seen in biology for setting a broken bone that allows for a better approximation of initial shape during healing processes and is likely the most important mechanical function. Our findings suggest a previously unidentified biomimetic design strategy in which tissue level material heterogeneity in foams can be used to improve deformation recovery after failure.

  10. The mechanical heterogeneity of the hard callus influences local tissue strains during bone healing: a finite element study based on sheep experiments.

    Science.gov (United States)

    Vetter, A; Liu, Y; Witt, F; Manjubala, I; Sander, O; Epari, D R; Fratzl, P; Duda, G N; Weinkamer, R

    2011-02-03

    During secondary fracture healing, various tissue types including new bone are formed. The local mechanical strains play an important role in tissue proliferation and differentiation. To further our mechanobiological understanding of fracture healing, a precise assessment of local strains is mandatory. Until now, static analyses using Finite Elements (FE) have assumed homogenous material properties. With the recent quantification of both the spatial tissue patterns (Vetter et al., 2010) and the development of elastic modulus of newly formed bone during healing (Manjubala et al., 2009), it is now possible to incorporate this heterogeneity. Therefore, the aim of this study is to investigate the effect of this heterogeneity on the strain patterns at six successive healing stages. The input data of the present work stemmed from a comprehensive cross-sectional study of sheep with a tibial osteotomy (Epari et al., 2006). In our FE model, each element containing bone was described by a bulk elastic modulus, which depended on both the local area fraction and the local elastic modulus of the bone material. The obtained strains were compared with the results of hypothetical FE models assuming homogeneous material properties. The differences in the spatial distributions of the strains between the heterogeneous and homogeneous FE models were interpreted using a current mechanobiological theory (Isakson et al., 2006). This interpretation showed that considering the heterogeneity of the hard callus is most important at the intermediate stages of healing, when cartilage transforms to bone via endochondral ossification. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Heterogeneous stock rat: a unique animal model for mapping genes influencing bone fragility.

    Science.gov (United States)

    Alam, Imranul; Koller, Daniel L; Sun, Qiwei; Roeder, Ryan K; Cañete, Toni; Blázquez, Gloria; López-Aumatell, Regina; Martínez-Membrives, Esther; Vicens-Costa, Elia; Mont, Carme; Díaz, Sira; Tobeña, Adolf; Fernández-Teruel, Alberto; Whitley, Adam; Strid, Pernilla; Diez, Margarita; Johannesson, Martina; Flint, Jonathan; Econs, Michael J; Turner, Charles H; Foroud, Tatiana

    2011-05-01

    Previously, we demonstrated that skeletal mass, structure and biomechanical properties vary considerably among 11 different inbred rat strains. Subsequently, we performed quantitative trait loci (QTL) analysis in four inbred rat strains (F344, LEW, COP and DA) for different bone phenotypes and identified several candidate genes influencing various bone traits. The standard approach to narrowing QTL intervals down to a few candidate genes typically employs the generation of congenic lines, which is time consuming and often not successful. A potential alternative approach is to use a highly genetically informative animal model resource capable of delivering very high resolution gene mapping such as Heterogeneous stock (HS) rat. HS rat was derived from eight inbred progenitors: ACI/N, BN/SsN, BUF/N, F344/N, M520/N, MR/N, WKY/N and WN/N. The genetic recombination pattern generated across 50 generations in these rats has been shown to deliver ultra-high even gene-level resolution for complex genetic studies. The purpose of this study is to investigate the usefulness of the HS rat model for fine mapping and identification of genes underlying bone fragility phenotypes. We compared bone geometry, density and strength phenotypes at multiple skeletal sites in HS rats with those obtained from five of the eight progenitor inbred strains. In addition, we estimated the heritability for different bone phenotypes in these rats and employed principal component analysis to explore relationships among bone phenotypes in the HS rats. Our study demonstrates that significant variability exists for different skeletal phenotypes in HS rats compared with their inbred progenitors. In addition, we estimated high heritability for several bone phenotypes and biologically interpretable factors explaining significant overall variability, suggesting that the HS rat model could be a unique genetic resource for rapid and efficient discovery of the genetic determinants of bone fragility. Copyright

  12. On the compensation effect in heterogeneous catalysis

    DEFF Research Database (Denmark)

    Pedersen, Thomas Bligaard; Honkala, Johanna Karoliina; Logadottir, Ashildur

    2003-01-01

    For a class of heterogeneously catalyzed reactions, we explain the compensation effect in terms of a switching of kinetic regimes leading to a concomitant change in the apparent activation energy and in the prefactor for the overall rate of the reaction. We first use the ammonia synthesis...

  13. Vanishing microwave effects : influence of heterogeneity

    NARCIS (Netherlands)

    Dressen, M.H.C.L.; Kruijs, van de B.H.P.; Meuldijk, J.; Vekemans, J.A.J.M.; Hulshof, L.A.

    2007-01-01

    A consistent setup of experiments has been conducted to demonstrate an enhanced reaction rate under microwave irradiation as compared to conventional heating, i.e. a real microwave effect. It was found that addition of a cosolvent, diminishing the heterogeneous character of the reaction mixture,

  14. Effects of heterogeneity on bank efficiency scores

    NARCIS (Netherlands)

    Bos, J. W. B.; Koetter, M.; Kolari, J. W.; Kool, C. J. M.

    2009-01-01

    Bank efficiency estimates often serve as a proxy of managerial skill since they quantify sub-optimal production choices. But such deviations can also be due to omitted systematic differences among banks. In this study, we examine the effects of heterogeneity on bank efficiency scores. We compare

  15. Heterogeneity within the spleen colony-forming cell population in rat bone marrow

    International Nuclear Information System (INIS)

    Martens, A.C.; van Bekkum, D.W.; Hagenbeek, A.

    1986-01-01

    The pluripotent hemopoietic stem cell (HSC) of the rat can be enumerated in a spleen colony assay (SCA) in rats as well as mice. After injection of rat bone marrow into lethally irradiated mice, macroscopically visible spleen colonies (CFU-S) are found from day 6 through 14, but the number varies on consecutive days. In normal bone marrow a constant ratio of day-8 to day-12 colony numbers is observed. However, this ratio is changed after in vivo treatment of rats with cyclophosphamide, as well as after in vitro treatment of rat bone marrow with cyclophosphamide derivatives. This indicates that the CFU-S that form colonies on day 8 react differently to this treatment than the CFU-S that form colonies on day 12, and suggests heterogeneity among the CFU-S population. Posttreatment regrowth of day-8 and day-12 CFU-S is characterized by differences in population-doubling times (Td = 0.85 days vs 1.65 days). Another argument in support of the postulate of heterogeneity within the rat CFU-S population is derived from the fact that (in contrast to normal rat spleen) the spleen of leukemic rats contains high numbers of CFU-S that show a ratio of day-8 to day-12 CFU-S of 4.5, which is different than that observed for a CFU-S population in normal bone marrow (a ratio of 2.4). It is concluded that, in rat hemopoiesis, two populations of spleen colony-forming cells can be distinguished using the rat-to-mouse SCA. This indicates that mouse and rat hemopoiesis are comparable in this respect and that heterogeneity in the stem cell compartment is a general phenomenon

  16. Characterization of Cellular and Molecular Heterogeneity of Bone Marrow Stromal Cells

    DEFF Research Database (Denmark)

    Elsafadi, Mona; Manikandan, Muthurangan; Atteya, Muhammad

    2016-01-01

    and osteoblast differentiation genes which included several homeobox genes: TBX15, HOXA2 and HOXA10, and IGF1, FGFR3, BMP6, MCAM, ITGA10, IGFBP5, and ALP. siRNA-based downregulation of the ALP gene in CL1 impaired osteoblastic and adipocytic differentiation. Our studies demonstrate the existence of molecular......Human bone marrow-derived stromal stem cells (hBMSC) exhibit multiple functions, including differentiation into skeletal cells (progenitor function), hematopoiesis support, and immune regulation (nonprogenitor function). We have previously demonstrated the presence of morphological and functional...... and functional heterogeneity in cultured hBMSC. ALP can be employed to identify osteoblastic and adipocytic progenitor cells in the heterogeneous hBMSC cultures...

  17. Heterogeneous and self-organizing mineralization of bone matrix promoted by hydroxyapatite nanoparticles.

    Science.gov (United States)

    Campi, G; Cristofaro, F; Pani, G; Fratini, M; Pascucci, B; Corsetto, P A; Weinhausen, B; Cedola, A; Rizzo, A M; Visai, L; Rea, G

    2017-11-16

    The mineralization process is crucial to the load-bearing characteristics of the bone extracellular matrix. In this work, we have studied the spatiotemporal dynamics of mineral deposition by human bone marrow mesenchymal stem cells differentiating toward osteoblasts promoted by the presence of exogenous hydroxyapatite nanoparticles. At the molecular level, the added nanoparticles positively modulated the expression of bone-specific markers and enhanced calcified matrix deposition during osteogenic differentiation. The nucleation, growth and spatial arrangement of newly deposited hydroxyapatite nanocrystals have been evaluated using scanning micro X-ray diffraction and scanning micro X-ray fluorescence. As leading results, we have found the emergence of a complex scenario where the spatial organization and temporal evolution of the process exhibit heterogeneous and self-organizing dynamics. At the same time the possibility of controlling the differentiation kinetics, through the addition of synthetic nanoparticles, paves the way to empower the generation of more structured bone scaffolds in tissue engineering and to design new drugs in regenerative medicine.

  18. Uncovering nanoscale electromechanical heterogeneity in the subfibrillar structure of collagen fibrils responsible for the piezoelectricity of bone.

    Science.gov (United States)

    Minary-Jolandan, Majid; Yu, Min-Feng

    2009-07-28

    Understanding piezoelectricity, the linear electromechanical transduction, in bone and tendon and its potential role in mechanoelectric transduction leading to their growth and remodeling remains a challenging subject. With high-resolution piezoresponse force microscopy, we probed piezoelectric behavior in relevant biological samples at different scale levels: from the subfibrillar structures of single isolated collagen fibrils to bone. We revealed that, beyond the general understanding of collagen fibril being a piezoelectric material, there existed an intrinsic piezoelectric heterogeneity within a collagen fibril coinciding with the periodic variation of its gap and overlap regions. This piezoelectric heterogeneity persisted even for the collagen fibrils embedded in bone, bringing about new implications for its possible roles in structural formation and remodeling of bone.

  19. Perfluoroalkyl substances in human bone: concentrations in bones and effects on bone cell differentiation.

    Science.gov (United States)

    Koskela, A; Koponen, J; Lehenkari, P; Viluksela, M; Korkalainen, M; Tuukkanen, J

    2017-07-28

    Perfluoroalkyl substances (PFAS), including two most commonly studied compounds perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are widely distributed environmental pollutants, used extensively earlier. Due to their toxicological effects the use of PFAS is now regulated. Based on earlier studies on PFOA's distribution in bone and bone marrow in mice, we investigated PFAS levels and their possible link to bone microarchitecture of human femoral bone samples (n = 18). Soft tissue and bone biopsies were also taken from a 49-year old female cadaver for PFAS analyses. We also studied how PFOA exposure affects differentiation of human osteoblasts and osteoclasts. PFAS were detectable from all dry bone and bone marrow samples, PFOS and PFOA being the most prominent. In cadaver biopsies, lungs and liver contained the highest concentrations of PFAS, whereas PFAS were absent in bone marrow. Perfluorononanoic acid (PFNA) was present in the bones, PFOA and PFOS were absent. In vitro results showed no disturbance in osteogenic differentiation after PFOA exposure, but in osteoclasts, lower concentrations led to increased resorption, which eventually dropped to zero after increase in PFOA concentration. In conclusion, PFAS are present in bone and have the potential to affect human bone cells partly at environmentally relevant concentrations.

  20. The effect of antiresorptives on bone quality.

    Science.gov (United States)

    Recker, Robert R; Armas, Laura

    2011-08-01

    Currently, antiresorptive therapy in the treatment and prevention of osteoporosis includes bisphosphonates, estrogen replacement, selective estrogen receptor modulators (raloxifene), and denosumab (a human antibody that inactivates RANKL). The original paradigm driving the development of antiresorptive therapy was that inhibition of bone resorption would allow bone formation to continue and correct the defect. However, it is now clear increases in bone density account for little of the antifracture effect of these treatments. We examined the antifracture benefit of antiresorptives deriving from bone quality changes. We searched the archive of nearly 30,000 articles accumulated over more than 40 years in our research center library using a software program (Refman™). Approximately 250 publications were identified in locating the 69 cited here. The findings document antiresorptive agents are not primarily anabolic. All cause a modest increase in bone density due to a reduction in the bone remodeling space; however, the majority of their efficacy is due to suppression of the primary cause of osteoporosis, ie, excessive bone remodeling not driven by mechanical need. All of them improve some element(s) of bone quality. Antiresorptive therapy reduces risk of fracture by improving bone quality through halting removal of bone tissue and the resultant destruction of microarchitecture of bone and, perhaps to some extent, by improving the intrinsic material properties of bone tissue. Information presented here may help clinicians to improve selection of patients for antiresorptive therapy by avoiding them in cases clearly not due to excessive bone remodeling.

  1. Heterogeneity of blood flow in tibial cortical bone: An experimental investigation using microspheres

    International Nuclear Information System (INIS)

    Willans, S.M.; McCarthy, I.D.

    1991-01-01

    The distribution of tibial blood flow was measured by injecting approximately (600-1000) x 10(3) 15 mu microspheres, labelled with either tin-113 (113Sn) or cobalt-57 (57Co) into femoral arteries of five mature greyhounds. The diaphyseal cortex, stripped of periosteum and devoid of marrow, was sawn into 40 pieces (10 transverse sections x 4 anatomical quarters/section). Relative deposition densities of the 113Sn microspheres in 40 pieces of cortex were found. These values, together with their associated masses, proved, from a statistical point of view, that flow rate heterogeneity was substantial in the diaphysis. In particular, for the diaphyseal cortex, distribution of relative deposition densities (flow rates) in six bones was found to be positively-skewed with a relative dispersion ((SD/mean) x 100) of approximately 40%

  2. Functional Heterogeneity and Senior Management Team Effectiveness

    Science.gov (United States)

    Benoliel, Pascale; Somech, Anit

    2016-01-01

    Purpose: There has been an increasing trend toward the creation of senior management teams (SMTs) which are characterized by a high degree of functional heterogeneity. Although such teams may create better linkages to information, along with the benefits of functional heterogeneity comes the potential for conflicts that stem from the value…

  3. Physical activity effects on bone metabolism.

    Science.gov (United States)

    Smith, E L; Gilligan, C

    1991-01-01

    The incidence of osteoporotic fractures rises exponentially with age and is increasing faster than the demographic increase in the aging population. Physical activity has great potential to reduce the risk for osteoporotic fractures. Three independent but interactive factors contribute to the risk of fractures: bone strength, the risk of falling, and the effectiveness of neuromuscular response that protects the skeleton from injury. Exercise can reduce fracture risk not only by preventing bone loss, but by decreasing the risk of falling and the force of impact by improving strength, flexibility, balance, and reaction time. Extreme inactivity causes rapid bone loss of up to 40%, while athletic activity results in bone hypertrophy of up to 40%. Exercise intervention programs have reduced bone loss or increased bone mass in both men and women of various ages and initial bone status. These benefits have been shown for arm bone mineral content, total body calcium, spine, calcium bone index, tibia, and calcaneus. In both middle-aged and elderly women, physical activity intervention reduced bone loss or increased bone mass. The mechanisms for maintenance of skeletal integrity rely on a cellular response to hormonal and mechanical load stimuli. Studies in animal models show that training affects cellular activity. In osteoporotics, cellular erosion is increased and mineral apposition rate (MAR) decreased compared with normal age-matched controls. In contrast to this, sows trained on a treadmill 20 min per day for 20 weeks had greater active periosteal surface, periosteal MAR, and osteonal MAR than untrained sows.

  4. [Bone Cell Biology Assessed by Microscopic Approach. The effect of parathyroid hormone and teriparatide on bone].

    Science.gov (United States)

    Takahata, Masahiko

    2015-10-01

    Continuous exposure to parathyroid hormone (PTH) leads to hypercalcemia and a decrease in bone volume, which is referred to as its catabolic effect, while intermittent exogenously administered PTH leads to an anabolic effect on bone. Intermittent administration of PTH dramatically increases bone remodeling and modeling through their direct and indirect effects on the functional cells of bone remodeling units and their precursors. These effects on bone metabolism differ according to dosing frequency of PTH. Therefore, different dosing frequency of PTH shows different therapeutic effects on bone in terms of bone volume and bone quality in patients with osteoporosis.

  5. Fourier transform infrared imaging of femoral neck bone: reduced heterogeneity of mineral-to-matrix and carbonate-to-phosphate and more variable crystallinity in treatment-naive fracture cases compared with fracture-free controls.

    Science.gov (United States)

    Gourion-Arsiquaud, Samuel; Lukashova, Lyudmilla; Power, Jon; Loveridge, Nigel; Reeve, Jonathan; Boskey, Adele L

    2013-01-01

    After the age of 60 years, hip fracture risk strongly increases, but only a fifth of this increase is attributable to reduced bone mineral density (BMD, measured clinically). Changes in bone quality, specifically bone composition as measured by Fourier transform infrared spectroscopic imaging (FTIRI), also contribute to fracture risk. Here, FTIRI was applied to study the femoral neck and provide spatially derived information on its mineral and matrix properties in age-matched fractured and nonfractured bones. Whole femoral neck cross sections, divided into quadrants along the neck's axis, from 10 women with hip fracture and 10 cadaveric controls were studied using FTIRI and micro-computed tomography. Although 3-dimensional micro-CT bone mineral densities were similar, the mineral-to-matrix ratio was reduced in the cases of hip fracture, confirming previous reports. New findings were that the FTIRI microscopic variation (heterogeneity) of the mineral-to-matrix ratio was substantially reduced in the fracture group as was the heterogeneity of the carbonate-to-phosphate ratio. Conversely, the heterogeneity of crystallinity was increased. Increased variation of crystallinity was statistically associated with reduced variation of the carbonate-to-phosphate ratio. Anatomical variation in these properties between the different femoral neck quadrants was reduced in the fracture group compared with controls. Although our treatment-naive patients had reduced rather than increased bending resistance, these changes in heterogeneity associated with hip fracture are in another way comparable to the effects of experimental bisphosphonate therapy, which decreases heterogeneity and other indicators of bone's toughness as a material. Copyright © 2013 American Society for Bone and Mineral Research.

  6. Effects of Spaceflight on Bone: The Rat as an Animal Model for Human Bone Loss

    Science.gov (United States)

    Halloran, B.; Weider, T.; Morey-Holton, E.

    1999-01-01

    The loss of weight bearing during spaceflight results in osteopenia in humans. Decrements in bone mineral reach 3-10% after as little as 75-184 days in space. Loss of bone mineral during flight decreases bone strength and increases fracture risk. The mechanisms responsible for, and the factors contributing to, the changes in bone induced by spaceflight are poorly understood. The rat has been widely used as an animal model for human bone loss during spaceflight. Despite its potential usefulness, the results of bone studies performed in the rat in space have been inconsistent. In some flights bone formation is decreased and cancellous bone volume reduced, while in others no significant changes in bone occur. In June of 1996 Drs. T. Wronski, S. Miller and myself participated in a flight experiment (STS 78) to examine the effects of glucocorticoids on bone during weightlessness. Technically the 17 day flight experiment was flawless. The results, however, were surprising. Cancellous bone volume and osteoblast surface in the proximal tibial metaphysis were the same in flight and ground-based control rats. Normal levels of cancellous bone mass and bone formation were also detected in the lumbar vertebrae and femoral neck of flight rats. Furthermore, periosteal bone formation rate was found to be identical in flight and ground-based control rats. Spaceflight had little or no effect on bone metabolism! These results prompted us to carefully review the changes in bone observed in, and the flight conditions of previous spaceflight missions.

  7. Measuring the effects of heterogeneity on distributed systems

    Science.gov (United States)

    El-Toweissy, Mohamed; Zeineldine, Osman; Mukkamala, Ravi

    1991-01-01

    Distributed computer systems in daily use are becoming more and more heterogeneous. Currently, much of the design and analysis studies of such systems assume homogeneity. This assumption of homogeneity has been mainly driven by the resulting simplicity in modeling and analysis. A simulation study is presented which investigated the effects of heterogeneity on scheduling algorithms for hard real time distributed systems. In contrast to previous results which indicate that random scheduling may be as good as a more complex scheduler, this algorithm is shown to be consistently better than a random scheduler. This conclusion is more prevalent at high workloads as well as at high levels of heterogeneity.

  8. The effect of heterogeneity on invasion in spatial epidemics

    DEFF Research Database (Denmark)

    Neri, Franco M; Bates, Anne; Füchtbauer, Winnie Sophie

    2011-01-01

    Heterogeneity in host populations is an important factor affecting the ability of a pathogen to invade, yet the quantitative investigation of its effects on epidemic spread is still an open problem. In this paper, we test recent theoretical results, which extend the established “percolation...... paradigm” to the spread of a pathogen in discrete heterogeneous host populations. In particular, we test the hypothesis that the probability of epidemic invasion decreases when host heterogeneity is increased. We use replicated experimental microcosms, in which the ubiquitous pathogenic fungus Rhizoctonia...

  9. Effective thermal neutron absorption cross section for heterogeneous mixture

    International Nuclear Information System (INIS)

    Gabanska, B.; Igielski, A.; Krynicka-Drozdowicz, E.; Woznicka, U.

    1989-01-01

    The first estimations (basing on Umiastowski's theory) of the influence of the sample heterogeneity of the effective thermal neutron absorption cross section were compared with the results obtained for the homogeneous mixture which components and concentration were the same as those of the heterogeneous sample. An experiment was prepared to determine how good this estimate is. Three artificial heterogeneous cylindrical samples (2R = H = 9 cm) were manufactured from pure silver cylinders embedded in plexiglass, keeping the Ag content and varying the size of cylinders (2R = H = 1.0 cm, 0.6 cm and 0.4 cm). Calculations performed show that the experimental effect of the sample heterogeneity can be significant. 5 figs., 5 tabs, 11 refs. (author)

  10. Intratumor heterogeneity alters most effective drugs in designed combinations.

    Science.gov (United States)

    Zhao, Boyang; Hemann, Michael T; Lauffenburger, Douglas A

    2014-07-22

    The substantial spatial and temporal heterogeneity observed in patient tumors poses considerable challenges for the design of effective drug combinations with predictable outcomes. Currently, the implications of tissue heterogeneity and sampling bias during diagnosis are unclear for selection and subsequent performance of potential combination therapies. Here, we apply a multiobjective computational optimization approach integrated with empirical information on efficacy and toxicity for individual drugs with respect to a spectrum of genetic perturbations, enabling derivation of optimal drug combinations for heterogeneous tumors comprising distributions of subpopulations possessing these perturbations. Analysis across probabilistic samplings from the spectrum of various possible distributions reveals that the most beneficial (considering both efficacy and toxicity) set of drugs changes as the complexity of genetic heterogeneity increases. Importantly, a significant likelihood arises that a drug selected as the most beneficial single agent with respect to the predominant subpopulation in fact does not reside within the most broadly useful drug combinations for heterogeneous tumors. The underlying explanation appears to be that heterogeneity essentially homogenizes the benefit of drug combinations, reducing the special advantage of a particular drug on a specific subpopulation. Thus, this study underscores the importance of considering heterogeneity in choosing drug combinations and offers a principled approach toward designing the most likely beneficial set, even if the subpopulation distribution is not precisely known.

  11. Exploring gamma radiation effect on exoelectron emission properties of bone

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, M.; Dekhtyar, Y.; Bogucharska, T.; Noskov, V. [Riga Technical Univ., Biomedical Engineering and Nanotechnology Institute (Latvia)

    2006-07-01

    Gamma radiation is used for radiation therapy to treat carcinogenic diseases including bone cancer. Ionising radiation kills carcinogenic calls. However, there are side effects of the gamma radiation on the bone surface electron structure. One of the effects is in the form of altering electron density of states of bone that, with time, influences biomedical reactions on bone life condition. (authors)

  12. Exploring gamma radiation effect on exoelectron emission properties of bone

    International Nuclear Information System (INIS)

    Zakaria, M.; Dekhtyar, Y.; Bogucharska, T.; Noskov, V.

    2006-01-01

    Gamma radiation is used for radiation therapy to treat carcinogenic diseases including bone cancer. Ionising radiation kills carcinogenic calls. However, there are side effects of the gamma radiation on the bone surface electron structure. One of the effects is in the form of altering electron density of states of bone that, with time, influences biomedical reactions on bone life condition. (authors)

  13. Local heterogeneity effects on small-sample worths

    International Nuclear Information System (INIS)

    Schaefer, R.W.

    1986-01-01

    One of the parameters usually measured in a fast reactor critical assembly is the reactivity associated with inserting a small sample of a material into the core (sample worth). Local heterogeneities introduced by the worth measurement techniques can have a significant effect on the sample worth. Unfortunately, the capability is lacking to model some of the heterogeneity effects associated with the experimental technique traditionally used at ANL (the radial tube technique). It has been suggested that these effects could account for a large portion of what remains of the longstanding central worth discrepancy. The purpose of this paper is to describe a large body of experimental data - most of which has never been reported - that shows the effect of radial tube-related local heterogeneities

  14. Heterogeneous Stock Rat: A Unique Animal Model for Mapping Genes Influencing Bone Fragility

    OpenAIRE

    Alam, Imranul; Koller, Daniel L.; Sun, Qiwei; Roeder, Ryan K.; Cañete, Toni; Blázquez, Gloria; López-Aumatell, Regina; Martínez-Membrives, Esther; Vicens-Costa, Elia; Mont, Carme; Díaz, Sira; Tobeña, Adolf; Fernández-Teruel, Alberto; Whitley, Adam; Strid, Pernilla

    2011-01-01

    Previously, we demonstrated that skeletal mass, structure and biomechanical properties vary considerably among 11 different inbred rat strains. Subsequently, we performed quantitative trait loci (QTL) analysis in 4 inbred rat strains (F344, LEW, COP and DA) for different bone phenotypes and identified several candidate genes influencing various bone traits. The standard approach to narrowing QTL intervals down to a few candidate genes typically employs the generation of congenic lines, which ...

  15. Heterogeneity in the effects of online persuasion

    NARCIS (Netherlands)

    Kaptein, M.C.; Eckles, D.

    2012-01-01

    Average effects of influence strategies on consumers' attitudes and behaviors have been studied extensively. Less is known about the relative size of individual differences in these effects, despite recognition of their importance in social psychology. Two experiments use repeated exposures to

  16. Heterogeneity in the Effects of Online Persuasion

    NARCIS (Netherlands)

    Kaptein, M.C.; Eckles, D.

    2012-01-01

    Average effects of influence strategies on consumers' attitudes and behaviors have been studied extensively. Less is known about the relative size of individual differences in these effects, despite recognition of their importance in social psychology. Two experiments use repeated exposures to

  17. Effect of random microstructure on crack propagation in cortical bone tissue under dynamic loading

    International Nuclear Information System (INIS)

    Gao, X; Li, S; Adel-Wahab, A; Silberschmidt, V

    2013-01-01

    A fracture process in a cortical bone tissue depends on various factors, such as bone loss, heterogeneous microstructure, variation of its material properties and accumulation of microcracks. Therefore, it is crucial to comprehend and describe the effect of microstructure and material properties of the components of cortical bone on crack propagation in a dynamic loading regime. At the microscale level, osteonal bone demonstrates a random distribution of osteons imbedded in an interstitial matrix and surrounded by a thin layer known as cement line. Such a distribution of osteons can lead to localization of deformation processes. The global mechanical behavior of bone and the crack-propagation process are affected by such localization under external loads. Hence, the random distribution of microstructural features plays a key role in the fracture process of cortical bone. The purpose of this study is two-fold: firstly, to develop two-dimensional microstructured numerical models of cortical bone tissue in order to examine the interaction between the propagating crack and bone microstructure using an extended finite-element method under both quasi-static and dynamic loading conditions; secondly, to investigate the effect of randomly distributed microstructural constituents on the crack propagation processes and crack paths. The obtained results of numerical simulations showed the influence of random microstructure on the global response of bone tissue at macroscale and on the crack-propagation process for quasi-static and dynamic loading conditions

  18. Effects of Growth Hormone on Bone.

    Science.gov (United States)

    Tritos, Nicholas A; Klibanski, Anne

    2016-01-01

    Describe the effects of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) on the skeleton. The GH and IGF-1 axis has pleiotropic effects on the skeleton throughout the lifespan by influencing bone formation and resorption. GH deficiency leads to decreased bone turnover, delayed statural growth in children, low bone mass, and increased fracture risk in adults. GH replacement improves adult stature in GH deficient children, increases bone mineral density (BMD) in adults, and helps to optimize peak bone acquisition in patients, during the transition from adolescence to adulthood, who have persistent GH deficiency. Observational studies suggest that GH replacement may mitigate the excessive fracture risk associated with GH deficiency. Acromegaly, a state of GH and IGF-1 excess, is associated with increased bone turnover and decreased BMD in the lumbar spine observed in some studies, particularly in patients with hypogonadism. In addition, patients with acromegaly appear to be at an increased risk of morphometric-vertebral fractures, especially in the presence of active disease or concurrent hypogonadism. GH therapy also has beneficial effects on statural growth in several conditions characterized by GH insensitivity, including chronic renal failure, Turner syndrome, Prader-Willi syndrome, postnatal growth delay in patients with intrauterine growth retardation who do not demonstrate catchup growth, idiopathic short stature, short stature homeobox-containing (SHOX) gene mutations, and Noonan syndrome. GH and IGF-1 have important roles in skeletal physiology, and GH has an important therapeutic role in both GH deficiency and insensitivity states. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Effect of tissue heterogeneity on quantification in positron emission tomography

    International Nuclear Information System (INIS)

    Blomqvist, G.; Lammertsma, A.A.; Mazoyer, B.; Wienhard, K.

    1995-01-01

    As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMR glc in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constans such as k 2 and k 3 for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameter k on .B max could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity, B max was found to be insensitive while K d was very sensitive to tissue heterogeneity. (orig.)

  20. Effect of tissue heterogeneity on quantification in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blomqvist, G [Dept. of Clinical Neuroscience, Experimental Alcohol and Drug Addiction Research Section, Karolinska Hospital, Stockholm (Sweden); Lammertsma, A A [PET Methodology Group, Cyclotron Unit, MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, London (United Kingdom); Mazoyer, B [Service Hospitalier Frederic Joliot CEA/Dept. de Biologie, Hopital d` Orsay and Antenne d` Informatique Medicale, Hopital Robert Debre, Paris (France); Wienhard, K [Max-Planck-Inst. fuer Neurologische Forschung, Koeln (Germany)

    1995-07-01

    As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMR{sub glc} in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constans such as k{sub 2} and k{sub 3} for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameter k{sub on}.B{sub max} could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity, B{sub max} was found to be insensitive while K{sub d} was very sensitive to tissue heterogeneity. (orig.)

  1. Effect of heterogeneities on evaluating earthquake triggering of volcanic eruptions

    Directory of Open Access Journals (Sweden)

    J. Takekawa

    2013-02-01

    Full Text Available Recent researches have indicated coupling between volcanic eruptions and earthquakes. Some of them calculated static stress transfer in subsurface induced by the occurrences of earthquakes. Most of their analyses ignored the spatial heterogeneity in subsurface, or only took into account the rigidity layering in the crust. On the other hand, a smaller scale heterogeneity of around hundreds of meters has been suggested by geophysical investigations. It is difficult to reflect that kind of heterogeneity in analysis models because accurate distributions of fluctuation are not well understood in many cases. Thus, the effect of the ignorance of the smaller scale heterogeneity on evaluating the earthquake triggering of volcanic eruptions is also not well understood. In the present study, we investigate the influence of the assumption of homogeneity on evaluating earthquake triggering of volcanic eruptions using finite element simulations. The crust is treated as a stochastic media with different heterogeneous parameters (correlation length and magnitude of velocity perturbation in our simulations. We adopt exponential and von Karman functions as spatial auto-correlation functions (ACF. In all our simulation results, the ignorance of the smaller scale heterogeneity leads to underestimation of the failure pressure around a chamber wall, which relates to dyke initiation. The magnitude of the velocity perturbation has a larger effect on the tensile failure at the chamber wall than the difference of the ACF and the correlation length. The maximum effect on the failure pressure in all our simulations is about twice larger than that in the homogeneous case. This indicates that the estimation of the earthquake triggering due to static stress transfer should take account of the heterogeneity of around hundreds of meters.

  2. Effects of radiations on bone marrow

    International Nuclear Information System (INIS)

    Tubiana, M.; Frindel, E.; Croizat, H.; Parmentier, C.

    1979-01-01

    After total body irradiation for kidney transplant, the initial decrease of circulating blood cells is more rapid, the nadir is reached sooner and the regeneration occurs earlier when the doses are higher than a few hundred rads. The LD 50 in man seems to be higher than 450 rads. The in vivo and in vitro assays of hemopoietic stem cells have greatly increasedd the understanding of acute and late effects. Multipotential stem cells are very radiosensitive, furthermore the differentiation of the surviving stem cells is accelerated after irradiation. This results in a severe depletion of the stem cell compartment. When this stem cell number falls below a critical value, the stem cell no longer differentiates till the completion of the regeneration of the stem cell compartment. Stem cell proliferation is regulated by inhibitors and stimulators. Release of stimulators by irradiated bone marrow has been demonstrated. Severe sequellae are observed after irradiation of animal and human bone marrow. They seem to be due either to the damage of the stromal cell or to the stem cell population. In patients, four compensating mechanisms are observed after a regional bone marrow irradiation: stimulation of non irradiated bone marrow, extension of hemopoietic areas, regeneration of irradiated bone marrow when the irradiated volume is large and increase in the amplification factor resulting in an increase in the output of mature cells for one stem cell input. Assay of progenitor cells provides useful information and a reduction in their number is still observed many years after a large regional irradiation

  3. Investigating the effect of heterogeneity on infill wells

    Directory of Open Access Journals (Sweden)

    Mahmood Bagheri

    2015-12-01

    Full Text Available Abstract In recent years, improving oil recovery (IOR has become an important subject for the petroleum industry. One IOR method is infill drilling, which improves hydrocarbon recovery from virgin zones of the reservoir. Determining the appropriate location for the infill wells is very challenging and greatly depends on different factors such as the reservoir heterogeneity. This study aims to investigate the effect of reservoir heterogeneity on the location of infill well. In order to characterize the effect of heterogeneity on infill well locations, some geostatistical methods, e.g., sequential gaussian simulation, have been applied to generate various heterogeneity models. In particular, different correlation ranges (R were used to observe the effect of heterogeneity. Results revealed that an increase in correlation ranges will lead to (1 a higher field oil production total, and (2 a faster expansion of the drainage radius which consequently reduced the need for infill wells. The results of this study will help engineers to appropriately design infill drilling schemes.

  4. Effect of parity on bone mineral density: A systematic review and meta-analysis.

    Science.gov (United States)

    Song, Seung Yeon; Kim, Yejee; Park, Hyunmin; Kim, Yun Joo; Kang, Wonku; Kim, Eun Young

    2017-08-01

    Parity has been suggested as a possible factor affecting bone health in women. However, study results on its association with bone mineral density are conflicting. PubMed, EMBASE, the Cochrane Library, and Korean online databases were searched using the terms "parity" and "bone mineral density", in May 2016. Two independent reviewers extracted the mean and standard deviation of bone mineral density measurements of the femoral neck, spine, and total hip in nulliparous and parous healthy women. Among the initial 10,146 studies, 10 articles comprising 24,771 women met the inclusion criteria. The overall effect of parity on bone mineral density was positive (mean difference=5.97mg/cm 2 ; 95% CI 2.37 to 9.57; P=0.001). The effect appears site-specific as parity was not significantly associated with the bone mineral density of the femoral neck (P=0.09) and lumbar spine (P=0.17), but parous women had significantly higher bone mineral density of the total hip compared to nulliparous women (mean difference=5.98mg/cm 2 ; 95% CI 1.72 to 10.24; P=0.006). No obvious heterogeneity existed among the included studies (femoral neck I 2 =0%; spine I 2 =31%; total hip I 2 =0%). Parity has a positive effect on bone in healthy, community-dwelling women and its effect appears site-specific. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Low cost guinea fowl bone derived recyclable heterogeneous catalyst for microwave assisted transesterification of Annona squamosa L. seed oil

    International Nuclear Information System (INIS)

    Singh, Veena; Sharma, Yogesh Chandra

    2017-01-01

    Highlights: • Discarded guinea fowl bone used to derive catalyst for biodiesel production. • High conversion of 95.82 ± 0.2% achieved in 20 min by microwave assisted transesterification of Annona Squamosa L. seed oil. • Catalyst was stable and can be reused up to five times by activation with >80% conversion. • Complete process is cheap, eco-friendly and fulfils ASTM standard limits. - Abstract: Guinea fowl bone derived heterogeneous catalyst was utilized for biodiesel production for the first time on microwave heating system from Annona squamosa (custard apple seed) oil. Synthesized catalyst was characterized by TGA, XRD, FTIR, SEM, EDS, BET surface area and basicity. Optimization for various reaction conditions on FAME conversion was explored. Maximum conversion of 95.82 ± 0.2% FAME was attained at 1:18 M ratio of oil: methanol, 4 wt% of catalyst at 800 W microwave power and 65 °C reaction temperatures for 20 min. Custard apple seed oil was studied by GCMS, whereas synthesized FAME was analysed by "1H FTNMR spectroscopy. Catalyst was reused up to five times with maximum conversion of >80%. Physicochemical properties of synthesized FAME were studied as per ASTM standards. Results displayed that catalyst derived from guinea fowl bone showed better reusability and has enormous potential to be used for biodiesel production under microwave irradiated transesterification of Annona squamosa L. (custard apple seed) oil within a short reaction time.

  6. The effects of surgicel and bone wax hemostatic agents on bone healing: An experimental study

    Directory of Open Access Journals (Sweden)

    Nasser Nooh

    2014-01-01

    Full Text Available Background: The biological effects of hemostatic agends on the physiological healing process need to be tested. The aim of this study was to assess the effects of oxidized cellulose (surgicel and bone wax on bone healing in goats′ feet. Materials and Methods: Three congruent circular bone defects were created on the lateral aspects of the right and left metacarpal bones of ten goats. One defect was left unfilled and acted as a control; the remaining two defects were filled with bone wax and surgicel respectively. The 10 animals were divided into two groups of 5 animals each, to be sacrificed at the 3rd and 5th week postoperatively. Histological analysis assessing quality of bone formed and micro-computed tomography (MCT measuring the quantities of bone volume (BV and bone density (BD were performed. The results of MCT analysis pertaining to BV and BD were statistically analyzed using two-way analysis of variance (ANOVA and posthoc least significant difference tests. Results: Histological analysis at 3 weeks showed granulation tissue with new bone formation in the control defects, active bone formation only at the borders for surgicel filled defects and fibrous encapsulation with foreign body reaction in the bone wax filled defects. At 5 weeks, the control and surgicel filled defects showed greater bone formation; however the control defects had the greatest amount of new bone. Bone wax filled defects showed very little bone formation. The two-way ANOVA for MCT results showed significant differences for BV and BD between the different hemostatic agents during the two examination periods. Conclusion: Surgicel has superiority over bone wax in terms of osseous healing. Bone wax significantly hinders osteogenesis and induces inflammation.

  7. Effects of low heterogeneity in fast critical assemblies

    International Nuclear Information System (INIS)

    Belov, S.P.; Dulin, V.A.; Zhukov, A.V.; Kuzin, E.N.; Mozhaev, V.K.; Sitnikov, V.I.; Tsibulya, A.M.; Shapar', A.V.; Zayfert, E.; Kuntsman, B.; Khayntsel'man, B.

    1989-01-01

    The problem of the low heterogeneity of fast critical assemblies, which are used to simulate fast reactors that are under design, has begun to assume increasing importance as the errors in nuclear data and group constants decrease and the capabilities of design codes improve. The design of the fuel channels of the fast critical assemblies of a BFS differs from that of the fuel subassemblies of a power reactor. The principal difference is that critical assemblies have a more heterogeneous structure than a reactor core does. As a result, the effects of this heterogeneity turn out to be appreciable for a number of functionals. Of particular interest was the measurement of the main neutronic characteristics of a fast reactor in its actual design and in the mockup produced by using BFS facilities. The authors measured and calculated the most important functionals (the ratios of the average cross sections of the main absorbing and fissioning elements, etc.) for both a homogeneous medium (fuel assemblies) and a heterogeneous medium (slugs, tubes) of practically identical composition. The objective of this work was to compare the discrepancy between experiment and calculations for the central functionals in the homogeneous and heterogeneous cases after corrections. This is a check of the accuracy of the simulation of homogeneous cores in fast power reactors by using the tools of the BFS fast critical assembly

  8. Effect of Heterogeneity in Initial Geographic Distribution on Opinions’ Competitiveness

    Directory of Open Access Journals (Sweden)

    Alexander S. Balankin

    2015-05-01

    Full Text Available Spin dynamics on networks allows us to understand how a global consensus emerges out of individual opinions. Here, we are interested in the effect of heterogeneity in the initial geographic distribution of a competing opinion on the competitiveness of its own opinion. Accordingly, in this work, we studied the effect of spatial heterogeneity on the majority rule dynamics using a three-state spin model, in which one state is neutral. Monte Carlo simulations were performed on square lattices divided into square blocks (cells. Accordingly, one competing opinion was distributed uniformly among cells, whereas the spatial distribution of the rival opinion was varied from the uniform to heterogeneous, with the median-to-mean ratio in the range from 1 to 0. When the size of discussion group is odd, the uncommitted agents disappear completely after  3.30 ± 0.05 update cycles, and then the system evolves in a two-state regime with complementary spatial distributions of two competing opinions. Even so, the initial heterogeneity in the spatial distribution of one of the competing opinions causes a decrease of this opinion competitiveness. That is, the opinion with initially heterogeneous spatial distribution has less probability to win, than the opinion with the initially uniform spatial distribution, even when the initial concentrations of both opinions are equal. We found that although the time to consensus , the opinion’s recession rate is determined during the first 3.3 update cycles. On the other hand, we found that the initial heterogeneity of the opinion spatial distribution assists the formation of quasi-stable regions, in which this opinion is dominant. The results of Monte Carlo simulations are discussed with regard to the electoral competition of political parties.

  9. Heterogenic transplantation of bone marrow-derived rhesus macaque mesenchymal stem cells ameliorates liver fibrosis induced by carbon tetrachloride in mouse

    Directory of Open Access Journals (Sweden)

    Xufeng Fu

    2018-02-01

    Full Text Available Liver fibrosis is a disease that causes high morbidity and has become a major health problem. Liver fibrosis can lead to the end stage of liver diseases (livercirrhosisand hepatocellularcarcinoma. Currently, liver transplantation is the only effective treatment for end-stage liver disease. However, the shortage of organ donors, high cost of medical surgery, immunological rejection and transplantation complications severely hamper liver transplantation therapy. Mesenchymal stem cells (MSCs have been regarded as promising cells for clinical applications in stem cell therapy in the treatment of liver diseases due to their unique multipotent differentiation capacity, immunoregulation and paracrine effects. Although liver fibrosis improvements by MSC transplantation in preclinical experiments as well as clinical trials have been reported, the in vivo fate of MSCs after transportation and their therapeutic mechanisms remain unclear. In this present study, we isolated MSCs from the bone marrow of rhesus macaques. The cells exhibited typical MSC markers and could differentiate into chondrocytes, osteocytes, and adipocytes, which were not affected by labeling with enhanced green fluorescent protein (EGFP. The harvested MSCs respond to interferon-γ stimulation and have the ability to inhibit lymphocyte proliferation in vitro. EGFP-labeled MSCs (1 × 106 cells were transplanted into mice with carbon tetrachloride-induced liver fibrosis via tail vein injection. The ability of the heterogenic MSC infusion to ameliorate liver fibrosis in mice was evaluated by a blood plasma chemistry index, pathological examination and liver fibrosis-associated gene expression. Additionally, a small number of MSCs that homed and engrafted in the mouse liver tissues were evaluated by immunofluorescence analysis. Our results showed that the transplantation of heterogenic MSCs derived from monkey bone marrow can be used to treat liver fibrosis in the mouse model and that the

  10. Osteoporotic-like effects of cadmium on bone mineral density and content in aged ovariectomized beagles

    International Nuclear Information System (INIS)

    Sacco-Gibson, N.; Abrams, J.; Chaudhry, S.; Hurst, D.; Peterson, D.; Bhattacharyya, M.

    1992-01-01

    Our purpose was to evaluate the effects of ovariectomy in conjunction with cadmium (Cd) exposure on bone. Aged female beagles with 45 Ca-labeled skeletons ovariectomized and exposed to Cd. Successive vertebral scans by dual photon absorptiometry monitored changes in bone mineral density (BMD) in each dog with time. Results showed that ovariectomy or Cd exposure alone caused significant decreases in BMD; ovariectomy with Cd exposure caused the greatest decrease. Ovariectomy alone did not decrease BMD in the distal end or mid-shaft of the tibia while BMD of the distal tibia decreased significantly due to Cd exposure alone. Combination treatment resulted in significant decreases in BMD of both tibial regions. At necropsy, tibiae, humeri, lumbar vertebrae and ribs were obtained for biochemical analysis. No group-to-group differences in bone weights (wet, dry, ash), in ash/dry ratios, or in long bone and vertebral Ca/dry or Ca/ash ratios were observed. Significantly higher total 45 Ca content and 45 Ca/dry and 45 Ca/ash ratios were observed in long bones and vertebrae of OV- and OV+ groups. In contrast, intact ribs showed significantly decreased Ca/dry and Ca/ash ratios compared to the SO-group. Quartered ribs demonstrated regional responses to specific treatment; decreases in total Ca content were greatest in the mid-rib region (-36 to -46%). Results suggest that in the aged female beagle, bone mineral loss associated with estrogen depletion is not only related to bone type (trabecular versus cortical) but also to bone Ca pools. Our results also suggest that a regional heterogeneity of bone plays a role in responsiveness to ovariectomy and Cd exposure. These aspects suggest that Cd is an exogenous factor affecting bone mineral loss independently of estrogen depletion. However, estrogen depletion primes bone for responsiveness to Cd-induced bone mineral loss

  11. Osteoporotic-like effects of cadmium on bone mineral density and content in aged ovariectomized beagles

    Energy Technology Data Exchange (ETDEWEB)

    Sacco-Gibson, N.; Abrams, J.; Chaudhry, S.; Hurst, D.; Peterson, D.; Bhattacharyya, M.

    1992-12-31

    Our purpose was to evaluate the effects of ovariectomy in conjunction with cadmium (Cd) exposure on bone. Aged female beagles with {sup 45}Ca-labeled skeletons ovariectomized and exposed to Cd. Successive vertebral scans by dual photon absorptiometry monitored changes in bone mineral density (BMD) in each dog with time. Results showed that ovariectomy or Cd exposure alone caused significant decreases in BMD; ovariectomy with Cd exposure caused the greatest decrease. Ovariectomy alone did not decrease BMD in the distal end or mid-shaft of the tibia while BMD of the distal tibia decreased significantly due to Cd exposure alone. Combination treatment resulted in significant decreases in BMD of both tibial regions. At necropsy, tibiae, humeri, lumbar vertebrae and ribs were obtained for biochemical analysis. No group-to-group differences in bone weights (wet, dry, ash), in ash/dry ratios, or in long bone and vertebral Ca/dry or Ca/ash ratios were observed. Significantly higher total {sup 45}Ca content and {sup 45}Ca/dry and {sup 45}Ca/ash ratios were observed in long bones and vertebrae of OV- and OV+ groups. In contrast, intact ribs showed significantly decreased Ca/dry and Ca/ash ratios compared to the SO-group. Quartered ribs demonstrated regional responses to specific treatment; decreases in total Ca content were greatest in the mid-rib region ({minus}36 to {minus}46%). Results suggest that in the aged female beagle, bone mineral loss associated with estrogen depletion is not only related to bone type (trabecular versus cortical) but also to bone Ca pools. Our results also suggest that a regional heterogeneity of bone plays a role in responsiveness to ovariectomy and Cd exposure. These aspects suggest that Cd is an exogenous factor affecting bone mineral loss independently of estrogen depletion. However, estrogen depletion primes bone for responsiveness to Cd-induced bone mineral loss.

  12. Fourier Transformed Infra-Red Imaging of Femoral Neck Bone: Reduced Heterogeneity of Mineral-to-Matrix and Carbonate-to-Phosphate and more Variable Crystallinity in Treatment-Naïve Fracture Cases compared to Fracture-Free Controls

    Science.gov (United States)

    Gourion-Arsiquaud, Samuel; Lukashova, Lyudmilla; Power, Jon; Loveridge, Nigel; Reeve, Jonathan; Boskey, Adele L.

    2012-01-01

    After age 60 hip fracture risk strongly increases, but only a fifth of this increase is attributable to reduced mineral density (BMD, measured clinically). Changes in bone quality, specifically bone composition as measured by Fourier Transform Infrared spectroscopic imaging (FTIRI), also contribute to fracture risk. Here, FTIRI was applied to study the femoral neck and provide spatially derived information on its mineral and matrix properties in age-matched fractured and non-fractured bones. Whole femoral neck cross sections, divided into quadrants along the neck’s axis, from 10 women with hip fracture and 10 cadaveric controls were studied using FTIRI and micro-computed Tomography. Although 3-dimensional micro-CT bone mineral densities were similar, the mineral-to-matrix ratio was reduced in the cases of hip fracture, confirming previous reports. New findings were that the FTIRI microscopic variation (heterogeneity) of the mineral-to-matrix ratio was substantially reduced in the fracture group as was the heterogeneity of the carbonate-to-phosphate ratio. Conversely, the heterogeneity of crystallinity was increased. Increased variation of crystallinity was statistically associated with reduced variation of the carbonate-to-phosphate ratio. Anatomical variation in these properties between the different femoral neck quadrants was reduced in the fracture group compared to controls. While our treatment-naïve patients had reduced rather than increased bending resistance, these changes in heterogeneity associated with hip fracture are in another way comparable to the effects of experimental bisphosphonate therapy, which decreases heterogeneity and other indicators of bone’s toughness as a material. PMID:22865771

  13. The effect of bone marrow aspirate, bone graft and collagen composites on fixation of bone implants

    DEFF Research Database (Denmark)

    Babiker, Hassan; Ding, Ming; Overgaard, Søren

    2007-01-01

     Introduction: Replacement of extensive local bone loss especially in revision joint arthroplasties is a significant clinical challenge. Autogenous and allogenic cancellous bone grafts have been the gold standard in reconstructive orthopaedic surgery, but it is well known that there is morbidity...... associated with harvesting of autogenous bone graft and limitations in the quantity of bone available. Disadvantages of allograft include the risk of bacterial or viral contamination and non union as well as the potential risk of disease transmission. Alternative options are attractive and continue...... to be sought. Hydroxyapatite and collagen composites have the potential in mimicking and replacing skeletal bones. Aim: This study attempted to determine the effect of hydroxyapatite/collagen composites in the fixation of bone implants. The composites used in this study is produced by Institute of Science...

  14. Computing effective properties of random heterogeneous materials on heterogeneous parallel processors

    Science.gov (United States)

    Leidi, Tiziano; Scocchi, Giulio; Grossi, Loris; Pusterla, Simone; D'Angelo, Claudio; Thiran, Jean-Philippe; Ortona, Alberto

    2012-11-01

    In recent decades, finite element (FE) techniques have been extensively used for predicting effective properties of random heterogeneous materials. In the case of very complex microstructures, the choice of numerical methods for the solution of this problem can offer some advantages over classical analytical approaches, and it allows the use of digital images obtained from real material samples (e.g., using computed tomography). On the other hand, having a large number of elements is often necessary for properly describing complex microstructures, ultimately leading to extremely time-consuming computations and high memory requirements. With the final objective of reducing these limitations, we improved an existing freely available FE code for the computation of effective conductivity (electrical and thermal) of microstructure digital models. To allow execution on hardware combining multi-core CPUs and a GPU, we first translated the original algorithm from Fortran to C, and we subdivided it into software components. Then, we enhanced the C version of the algorithm for parallel processing with heterogeneous processors. With the goal of maximizing the obtained performances and limiting resource consumption, we utilized a software architecture based on stream processing, event-driven scheduling, and dynamic load balancing. The parallel processing version of the algorithm has been validated using a simple microstructure consisting of a single sphere located at the centre of a cubic box, yielding consistent results. Finally, the code was used for the calculation of the effective thermal conductivity of a digital model of a real sample (a ceramic foam obtained using X-ray computed tomography). On a computer equipped with dual hexa-core Intel Xeon X5670 processors and an NVIDIA Tesla C2050, the parallel application version features near to linear speed-up progression when using only the CPU cores. It executes more than 20 times faster when additionally using the GPU.

  15. Effect of treadmill gait on bone markers and bone mineral density of quadriplegic subjects

    Directory of Open Access Journals (Sweden)

    D.C.L. Carvalho

    2006-10-01

    Full Text Available Quadriplegic subjects present extensive muscle mass paralysis which is responsible for the dramatic decrease in bone mass, increasing the risk of bone fractures. There has been much effort to find an efficient treatment to prevent or reverse this significant bone loss. We used 21 male subjects, mean age 31.95 ± 8.01 years, with chronic quadriplegia, between C4 and C8, to evaluate the effect of treadmill gait training using neuromuscular electrical stimulation, with 30-50% weight relief, on bone mass, comparing individual dual-energy X-ray absorptiometry responses and biochemical markers of bone metabolism. Subjects were divided into gait (N = 11 and control (N = 10 groups. The gait group underwent gait training for 6 months, twice a week, for 20 min, while the control group did not perform gait. Bone mineral density (BMD of lumbar spine, femoral neck, trochanteric area, and total femur, and biochemical markers (osteocalcin, bone alkaline phosphatase, pyridinoline, and deoxypyridinoline were measured at the beginning of the study and 6 months later. In the gait group, 81.8% of the subjects presented a significant increase in bone formation and 66.7% also presented a significant decrease of bone resorption markers, whereas 30% of the controls did not present any change in markers and 20% presented an increase in bone formation. Marker results did not always agree with BMD data. Indeed, many individuals with increased bone formation presented a decrease in BMD. Most individuals in the gait group presented an increase in bone formation markers and a decrease in bone resorption markers, suggesting that gait training, even with 30-50% body weight support, was efficient in improving the bone mass of chronic quadriplegics.

  16. Scattering theory and effective medium approximations to heterogeneous materials

    International Nuclear Information System (INIS)

    Gubernatis, J.E.

    1977-01-01

    The formal analogy existing between problems studied in the microscopic theory of disordered alloys and problems concerned with the effective (macroscopic) behavior of heterogeneous materials is discussed. Attention is focused on (1) analogous approximations (effective medium approximations) developed for the microscopic problems by scattering theory concepts and techniques, but for the macroscopic problems principally by intuitive means, (2) the link, provided by scattering theory, of the intuitively developed approximations to a well-defined perturbative analysis, (3) the possible presence of conditionally convergent integrals in effective medium approximations

  17. Heterogeneous Effects of a Nonlinear Price Schedule for Outpatient Care.

    Science.gov (United States)

    Farbmacher, Helmut; Ihle, Peter; Schubert, Ingrid; Winter, Joachim; Wuppermann, Amelie

    2017-10-01

    Nonlinear price schedules generally have heterogeneous effects on health-care demand. We develop and apply a finite mixture bivariate probit model to analyze whether there are heterogeneous reactions to the introduction of a nonlinear price schedule in the German statutory health insurance system. In administrative insurance claims data from the largest German health insurance plan, we find that some individuals strongly react to the new price schedule while a second group of individuals does not react. Post-estimation analyses reveal that the group of the individuals who do not react to the reform includes the relatively sick. These results are in line with forward-looking behavior: Individuals who are already sick expect that they will hit the kink in the price schedule and thus are less sensitive to the co-payment. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Effect of epimedium pubescen flavonoid on bone mineral status and bone turnover in male rats chronically exposed to cigarette smoke.

    Science.gov (United States)

    Gao, Shu-guang; Cheng, Ling; Li, Kang-hua; Liu, Wen-He; Xu, Mai; Jiang, Wei; Wei, Li-Cheng; Zhang, Fang-jie; Xiao, Wen-feng; Xiong, Yi-lin; Tian, Jian; Zeng, Chao; Sun, Jin-peng; Xie, Qiang; Lei, Guang-hua

    2012-06-19

    Epimedii herba is one of the most frequently used herbs in formulas that are prescribed for the treatment of osteoporosis in China and its main constituent is Epimedium pubescen flavonoid (EPF). However, it is unclear whether EPF during chronic exposure to cigarette smoke may have a protective influence on the skeleton. The present study investigated the effect of EPF on bone mineral status and bone turnover in a rat model of human relatively high exposure to cigarette smoke. Fifty male Wistar rats were randomized into five groups: controls, passive smoking groups and passive smoking rats administered EPF at three dosage levels (75, 150 or 300 mg/kg/day) in drinking water for 4 months. A rat model of passive smoking was prepared by breeding male rats in a cigarette-smoking box. Bone mineral content (BMC), bone mineral density (BMD), bone turnover markers, bone histomorphometric parameters and biomechanical properties were examined. Smoke exposure decreased BMC and BMD, increased bone turnover (inhibited bone formation and stimulated its resorption), affected bone histomorphometry (increased trabecular separation and osteoclast surface per bone surface; decreased trabecular bone volume, trabecular thickness, trabecular number, cortical thickness, bone formation rate and osteoblast surface per bone surface), and reduced mechanical properties. EPF supplementation during cigarette smoke exposure prevented smoke-induced changes in bone mineral status and bone turnover. The results suggest that EPF can prevent the adverse effects of smoke exposure on bone by stimulating bone formation and inhibiting bone turnover and bone resorption.

  19. Monte Carlo simulation of the Leksell Gamma KnifeTM: II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Moskvin, Vadim; Timmerman, Robert; DesRosiers, Colleen; Randall, Marcus; DesRosiers, Paul; Dittmer, Phil; Papiez, Lech

    2004-01-01

    The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife TM . The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan TM ) at up to 4 mm from an interface. The dose delivered to the target area away from an air-tissue interface may be underestimated by up to 7% by GammaPlan TM due to overestimation of attenuation of photon beams passing through air cavities. While the underdosing near the air-tissue interface cannot be eliminated with any plug pattern, the overdosage due to under-attenuation of the photon beams in air cavities can be eliminated by plugging the sources whose beams intersect the air cavity. Little perturbation was observed next to bone-tissue interfaces. Monte Carlo results were confirmed by measurements. This study shows that the employed Monte Carlo treatment planning is more accurate for precise dosimetry of stereotactic radiosurgery with the Leksell Gamma Knife TM for targets in the vicinity of air-filled cavities

  20. Effect of cisplatin on bone transport osteogenesis in dogs.

    Science.gov (United States)

    Ehrhart, Nicole; Eurell, Jo Ann C; Tommasini, Matteo; Constable, Peter D; Johnson, Ann L; Feretti, Antonio

    2002-05-01

    To document effects of cisplatin on regenerate bone formation during the distraction and consolidation phases of bone transport osteogenesis. 10 skeletally mature hounds. Bone transport osteogenesis was performed to reconstruct a 3-cm defect in the radius of each dog. Five dogs were randomly selected to receive cisplatin (70 mg/m2, IV, q 21 d for 4 cycles), and 5 were administered saline (0.9% NaCl) solution. Bone mineral density was measured by use of dual-energy x-ray absorptiometry (DEXA) on days 24, 55, and 90 after surgery. Dogs were euthanatized 90 days after surgery. Histomorphometry was performed on nondecalcified sections of regenerate bone. Bone mineral density and histomorphometric indices of newly formed bone were compared between groups. Densitometric differences in regenerate bone mineral density were not detected between groups at any time period. Cisplatin-treated dogs had decreased mineralized bone volume, decreased percentage of woven bone volume, decreased percentage of osteoblast-covered bone, increased porosity, and increased percentage of osteoblast-covered surfaces, compared with values for control dogs. Lamellar bone volume and osteoid volume did not differ significantly between groups. Regenerate bone will form and remodel during administration of cisplatin. Results of histomorphometric analysis suggest that bone formation and resorption may be uncoupled in cisplatin-treated regenerate bone as a result of increased osteoclast activity or delayed secondary bone formation during remodeling. These histomorphometric differences were modest in magnitude and did not result in clinically observable complications or decreased bone mineral density as measured by use of DEXA.

  1. Physical heterogeneity control on effective mineral dissolution rates

    Science.gov (United States)

    Jung, Heewon; Navarre-Sitchler, Alexis

    2018-04-01

    Hydrologic heterogeneity may be an important factor contributing to the discrepancy in laboratory and field measured dissolution rates, but the governing factors influencing mineral dissolution rates among various representations of physical heterogeneity remain poorly understood. Here, we present multiple reactive transport simulations of anorthite dissolution in 2D latticed random permeability fields and link the information from local grid scale (1 cm or 4 m) dissolution rates to domain-scale (1m or 400 m) effective dissolution rates measured by the flux-weighted average of an ensemble of flow paths. We compare results of homogeneous models to heterogeneous models with different structure and layered permeability distributions within the model domain. Chemistry is simplified to a single dissolving primary mineral (anorthite) distributed homogeneously throughout the domain and a single secondary mineral (kaolinite) that is allowed to dissolve or precipitate. Results show that increasing size in correlation structure (i.e. long integral scales) and high variance in permeability distribution are two important factors inducing a reduction in effective mineral dissolution rates compared to homogeneous permeability domains. Larger correlation structures produce larger zones of low permeability where diffusion is an important transport mechanism. Due to the increased residence time under slow diffusive transport, the saturation state of a solute with respect to a reacting mineral approaches equilibrium and reduces the reaction rate. High variance in permeability distribution favorably develops large low permeability zones that intensifies the reduction in mixing and effective dissolution rate. However, the degree of reduction in effective dissolution rate observed in 1 m × 1 m domains is too small (equilibrium conditions reduce the effective dissolution rate by increasing the saturation state. However, in large domains where less- or non-reactive zones develop, higher

  2. Inertial Effects on Flow and Transport in Heterogeneous Porous Media.

    Science.gov (United States)

    Nissan, Alon; Berkowitz, Brian

    2018-02-02

    We investigate the effects of high fluid velocities on flow and tracer transport in heterogeneous porous media. We simulate fluid flow and advective transport through two-dimensional pore-scale matrices with varying structural complexity. As the Reynolds number increases, the flow regime transitions from linear to nonlinear; this behavior is controlled by the medium structure, where higher complexity amplifies inertial effects. The result is, nonintuitively, increased homogenization of the flow field, which leads in the context of conservative chemical transport to less anomalous behavior. We quantify the transport patterns via a continuous time random walk, using the spatial distribution of the kinetic energy within the fluid as a characteristic measure.

  3. On heterogeneity of treatment effects and clinical freedom.

    Science.gov (United States)

    Sacristán, J A; Avendaño-Solá, C

    2015-01-01

    Three decades ago, John R Hampton announced the death of clinical freedom. Since then, evidence-based medicine has been the predominant paradigm in clinical research. By applying a population-based approach, the randomised controlled trial has become the cornerstone for demonstrating the overall effect of a treatment and for developing guidelines. The new patient-centred medicine movement is rediscovering the important implications of heterogeneity of treatment effects for clinical practice and that a better understanding of such variability can contribute to improve health outcomes for individual patients through practicing a science-based clinical freedom. © 2015 The Authors. International Journal of Clinical Practice Published by John Wiley & Sons Ltd.

  4. The Effect of Aloe, Gelfoam, Plaster on Bone Formation in applying to the bone defect

    International Nuclear Information System (INIS)

    Choi, Eui Hwan; Kim, Su Gwan

    1999-01-01

    This study was to evaluate the effects of Aloe, Gelfoam, and Plaster of Paris on bone healing. Four experimental defects were created for placement of the three materials in the right femur of dogs. One defect served as an empty control site. The evaluation was performed at 1-, 6-, and 12-weeks by light microscopy and NIH image program. Radiographic and Histologic examinations showed new bone formation in the presence of Aloe, Gelfoam, and Plaster of Paris and similar bone healing reactions. On the basis of these findings, it was concluded that Aloe, Gelfoam, and Plaster of Paris may be adequate agents for use in bone procurement.

  5. Effects of fault heterogeneity on seismic energy and spectrum

    Science.gov (United States)

    Dragoni, Michele; Santini, Stefano

    2017-12-01

    We study the effects of friction heterogeneity on the dynamics of a seismogenic fault. To this aim, we consider a fault model containing two asperities with different static frictions and a rate-dependent dynamic friction. We consider the seismic events produced by the consecutive failure of the two asperities and study their properties as functions of the ratio between static frictions. In particular, we calculate the moment rate, the stress evolution during fault slip, the average stress drop, the partitioning of energy release, the seismic energy, the far-field waveforms and the spectrum of seismic waves. These quantities depend to various extent on the friction distribution on the fault. In particular, the stress distribution on the fault is always strongly heterogeneous at the beginning of the seismic event. Seismic energy and frictional heat decrease with increasing friction heterogeneity, while seismic efficiency is constant. We obtain an equation relating seismic efficiency to the parameters of the friction law, showing that the efficiency is maximum for smaller values of dynamic friction. The seismic spectrum depends on the friction distribution as to the positions and the values of the minima. However, under the model assumption that the slip durations are the same for both asperities, the corner frequency is independent of the friction distribution, but it depends on the friction law and on the coupling between asperities. The model provides a relation between the total radiated energy and the seismic moment that is consistent with the empirical relation between the two quantities. The fault model with one asperity is also considered as a particular case. The model is applied to the 1965 Rat Islands (Alaska) earthquake and shows the role of fault heterogeneity in controlling the spatial distribution of stress drop as well as the time dependence and the final amount of radiated energy.

  6. Various effects of antidepressant drugs on bone microarchitectecture, mechanical properties and bone remodeling

    International Nuclear Information System (INIS)

    Bonnet, N.; Bernard, P.; Beaupied, H; Bizot, J.C.; Trovero, F.; Courteix, D.; Benhamou, C.L.

    2007-01-01

    The aim of this study was to evaluate the effects of various drugs which present antidepressant properties: selective serotonin-reuptake inhibitors (SSRIs, fluoxetine), serotonin and noradrenaline-reuptake inhibitors (Desipramine) and phosphodiesterase inhibitors (PDE, rolipram and tofisopam) on bone microarchitecture and biomechanical properties. Twelve female mice were studied per group starting at an age of 10 weeks. During 4 weeks, they received subcutaneously either placebo or 20 mg kg -1 day -1 of desipramine, fluoxetine or 10 mg kg -1 day -1 of rolipram or tofisopam. Serum Osteocalcin and CTx were evaluated by ELISA. Bone microarchitecture of the distal femur was characterized by X-ray microCT (Skyscan1072). Mechanical properties were assessed by three-point bending test (Instron 4501) and antidepressant efficacy by forced swimming and open field tests. Fluoxetine displayed lower TbTh (- 6.1%, p -1 , 6431 ± 1182 MPa) than in placebo (101 ± 9 N mm -1 , 8441 ± 1180 MPa). Bone markers indicated a significantly higher bone formation in tofisopam (+ 8.6%) and a lower in fluoxetine (- 56.1%) compared to placebo. These data suggest deleterious effects for SSRIs, both on trabecular and cortical bone and a positive effect of PDE inhibitors on trabecular bone. Furthermore tofisopam anabolic effect in terms of bone markers, suggests a potential therapeutic effect of the PDE inhibitors on bone

  7. Compacted cancellous bone has a spring-back effect

    DEFF Research Database (Denmark)

    Kold, S; Bechtold, JE; Ding, Ming

    2003-01-01

    A new surgical technique, compaction, has been shown to improve implant fixation. It has been speculated that the enhanced implant fixation with compaction could be due to a spring-back effect of compacted bone. However, such an effect has yet to be shown. Therefore we investigated in a canine mo....... Thus we found a spring-back effect of compacted bone, which may be important for increasing implant fixation by reducing initial gaps between the implant and bone....

  8. Effects of Fermented Milk Products on Bone.

    Science.gov (United States)

    Rizzoli, René; Biver, Emmanuel

    2018-04-01

    Fermented milk products like yogurt or soft cheese provide calcium, phosphorus, and protein. All these nutrients influence bone growth and bone loss. In addition, fermented milk products may contain prebiotics like inulin which may be added to yogurt, and provide probiotics which are capable of modifying intestinal calcium absorption and/or bone metabolism. On the other hand, yogurt consumption may ensure a more regular ingestion of milk products and higher compliance, because of various flavors and sweetness. Bone mass accrual, bone homeostasis, and attenuation of sex hormone deficiency-induced bone loss seem to benefit from calcium, protein, pre-, or probiotics ingestion, which may modify gut microbiota composition and metabolism. Fermented milk products might also represent a marker of lifestyle promoting healthy bone health.

  9. Effect of Heterogeneity of JSFR Fuel Assemblies to Power Distribution

    International Nuclear Information System (INIS)

    Takeda, Toshikazu; Shimazu, Yoichiro; Hibi, Koki; Fujimura, Koji

    2013-01-01

    Conclusion: 1) Strong heterogeneity of JSFR assemblies was successfully calculated by BACH. 2) Verification test of BACH: • Infinite assembly model; • Color set model; • Good agreement with Monte-Carlo results. 3) Core calculations 3 models for inner duct was used; inward model, outward model and homogeneous model. • k eff difference between the inward and out ward model → 0.3%Δk; • ~20% effect on flux and power distributions. Therefore, we have to pay careful attention for the location of inner duct in fuel loading of JSFR

  10. The effect of radiation therapy on bone scintigraphy

    International Nuclear Information System (INIS)

    Kado, Bunmei; Nakajima, Tetsuo; Sakura, Mizuyoshi; Ishihara, Akinori; Sasaki, Yasuhito; Nagai, Teruo.

    1982-01-01

    With the purpose to evaluate effect of radiation therapy on bone scintigraphy, ninety nine bone scans and Ga-67 citrate tumor scans were performed on 67 patients, including 42 with lung cancer, 5 with esophageal cancer, 4 malignant lymphoma and 15 with other malignancy. The spinal uptake of Tc-99m diphosphonate and Ga-67 citrate were evaluated during or after radiation therapy involving thoracic and lumbar spines. The correlation among the spinal uptake of radioactivity in the radiation field, the irradiation dose and the interval after radiotherapy was investigated. The results revealed that 34 of 99 bone scans (34%) showed ''decreased'' radioactivity in the irradiated spines. Twenty six of 41 bone scans (63%) performed more than three months after radiotherapy showed ''decreased'' spinal uptake. Among the same 41 bone scans, 16 of 21 bone scans (76%) taken in patients who received more than 5000 rads showed ''decreased'' spinal uptake. The decreased spinal uptake was irreversible. Eight cases changed to ''decreased'' from ''equilibrated'' during follow up study after radiotherapy. Twenty two of 31 cases (71%) with Ga tumor scans, which were performed in the earlier periods and with less dose of radiotherapy as compared with bone scans, showed ''decreased'' spinal uptake, which suggests impaired Ga-67 uptake by the bone marrow rather than the spinal bone. The factors causing decreased uptake of radioactivity in bone scan after irradiation were discussed in view of irradiation effect on bone tissue. The descrepancy of uptake of radioactivity between bone scan and Ga tumor scan was also discussed reviewing difference of radiation effect on bone and bone marrow cells. (author)

  11. Late effects of radiation on mature and growing bone

    International Nuclear Information System (INIS)

    Ramuz, O.; Mornex, F.; Bourhis, J.

    1997-01-01

    The physiopathology of radiation-induced bone damage is no completely elucidated. Ionizing radiation may induce an inhibition or an impairment of growing bone. This fact is of particular importance in children, and represents one of the most important dose-limiting factors in the radiotherapeutic management of children with malignant diseases. Scoliosis, epiphyseal slippage, avascular necrosis, abnormalities of craniofacial growth may be observed after radiation. Child's age at the time of treatment, location of irradiated bone and irradiation characteristics may influence the radiation related observed effects. In adults, pathological analysis of mature bone after ionizing radiation exposure are rare, suggesting that it is difficult to draw a clear feature of the action of radiation on the bone. Osteoporosis, medullary fibrosis and cytotoxicity on bone cells lead to fracture or necrosis. Various factors can influence bone tolerance to radiation such as bone involvement by tumor cells or infection, which is frequent is mandibulary osteoradionecrosis. Technical improvements in radiation techniques have also decreased radio-induced bone complications : the volume, fractionation and total dose are essential to consider. The absence of a consistent radiation-induced late effects evaluation scale has hampered efforts to analyze the influence of various therapeutic maneuvers and the comparison of results from different reported series. The currently proposed evaluation scale may help harmonizing the classification of radiation-induced bone late effects. (author)

  12. Disuse exaggerates the detrimental effects of alcohol on cortical bone

    Science.gov (United States)

    Hefferan, Theresa E.; Kennedy, Angela M.; Evans, Glenda L.; Turner, Russell T.

    2003-01-01

    BACKGROUND: Alcohol abuse is associated with an increased risk for osteoporosis. However, comorbidity factors may play an important role in the pathogenesis of alcohol-related bone fractures. Suboptimal mechanical loading of the skeleton, an established risk factor for bone loss, may occur in some alcohol abusers due to reduced physical activity, muscle atrophy, or both. The effect of alcohol consumption and reduced physical activity on bone metabolism has not been well studied. The purpose of this study was to determine whether mechanical disuse alters bone metabolism in a rat model for chronic alcohol abuse. METHODS: Alcohol was administered in the diet (35% caloric intake) of 6-month-old male rats for 4 weeks. Rats were hindlimb-unloaded the final 2 weeks of the experiment to prevent dynamic weight bearing. Afterward, cortical bone histomorphometry was evaluated at the tibia-fibula synostosis. RESULTS: At the periosteal surface of the tibial diaphysis, alcohol and hindlimb unloading independently decreased the mineralizing perimeter, mineral apposition rate, and bone formation rate. In addition, alcohol, but not hindlimb unloading, increased endocortical bone resorption. The respective detrimental effects of alcohol and hindlimb unloading to inhibit bone formation were additive; there was no interaction between the two variables. CONCLUSIONS: Reduced weight bearing accentuates the detrimental effects of alcohol on cortical bone in adult male rats by further inhibiting bone formation. This finding suggests that reduced physical activity may be a comorbidity factor for osteoporosis in alcohol abusers.

  13. Effect of catalysts on heterogeneous oxidation of coal

    Energy Technology Data Exchange (ETDEWEB)

    Glazkova, A P; Kazarova, Yu A; Suslov, A V

    1978-01-01

    Analyzes the effects of catalysts on the heterogeneous oxidation of coal in deflagration processes of stoichiometric mixtures. The following substances are studied as catalysts: alkali and alkaline-earth metals, and compounds of copper, lead, chromium, iron, and sulfur. In the first case the catalysts are used in the form of nitrates and the nitrate simultaneously plays the role of an oxidizer. In the second case the catalysts are added to stoichiometric mixtures of ammonium nitrate with carbon. It is shown that during carbon oxidation by nitrates the catalytic efficiency of the metals studied forms the following order: sodium > lead > potassium > barium > aluminium > calcium > magnesium > copper. The calculated and experimental parameters of combustion are given. The problem of dependence of combustion rate on combustion heat, the mechanism of the combustion reaction and the catalytic effects of the additives are discussed. Features of heterogeneous catalysis in the oxidation process of carbon by various oxidizers are analyzed. The investigations on the combustion process are important as the process takes place during explosion of coal dust in underground coal mines and during burning of coal in industrial furnaces. (34 refs.) (In Russian)

  14. The effects of bone marrow aspirate, bone graft, and collagen composites on fixation of titanium implants

    DEFF Research Database (Denmark)

    Babiker, Hassan; Ding, Ming; Sandri, Monica

    2012-01-01

    Replacement of extensive local bone loss especially in revision joint arthroplasty and spine fusion is a significant clinical challenge. Allograft and autograft have been considered as gold standards for bone replacement. However, there are several disadvantages such as donor site pain, bacterial...... contamination, and non union as well as the potential risk of disease transmission. Hydroxyapatite and collagen composites (HA/Collagen) have the potential in mimicking and replacing skeletal bones. This study attempted to determine the effects of newly developed HA/Collagen-composites with and without bone...... marrow aspirate (BMA) on enhancement of bone implant fixation. Method: Titanium alloy implants were inserted into bilateral femoral condyles of eight skeletally mature sheep, four implants per sheep. The implant had a circumferential gap of 2 mm. The gap was filled with: HA/Collagen; HA...

  15. Effects of developmental exposure to perfluorooctanoic acid (PFOA) on long bone morphology and bone cell differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Koskela, A., E-mail: antti.koskela@oulu.fi [Institute of Cancer Research and Translational Medicine, MRC Oulu and Department of Anatomy and Cell Biology, Faculty of Medicine, University of Oulu, Oulu (Finland); Finnilä, M.A. [Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu (Finland); Korkalainen, M. [National Institute for Health and Welfare, Department of Health Protection, Kuopio (Finland); Spulber, S. [Department of Neuroscience, Karolinska Institutet, Stockholm (Sweden); Koponen, J. [National Institute for Health and Welfare, Department of Health Protection, Kuopio (Finland); Håkansson, H. [Institute of Environmental Medicine, Karolinska Institutet, Stockholm (Sweden); Tuukkanen, J. [Institute of Cancer Research and Translational Medicine, MRC Oulu and Department of Anatomy and Cell Biology, Faculty of Medicine, University of Oulu, Oulu (Finland); Viluksela, M. [National Institute for Health and Welfare, Department of Health Protection, Kuopio (Finland); Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio (Finland)

    2016-06-15

    Perfluorooctanoic acid (PFOA) is a ubiquitous and persistent environmental chemical, which has been used extensively due to its stability and surface tension-lowering properties. Toxicological effects include induction of neonatal mortality and reproductive toxicity. In this study, pregnant C57BL/6 mice were exposed orally to 0.3 mg PFOA/kg/day throughout pregnancy, and female offspring were studied at the age of 13 or 17 months. Morphometrical and biomechanical properties of femurs and tibias were analyzed with micro-computed tomography and 3-point bending, and bone PFOA concentrations were determined by mass spectrometry. The effects of PFOA on bone cell differentiation were studied in osteoclasts from C57BL/6 mice and in the MC3T3 pre-osteoblast cell line. PFOA exposed mice showed increased femoral periosteal area as well as decreased mineral density of tibias. Biomechanical properties of these bones were not affected. Bone PFOA concentrations were clearly elevated even at the age of 17 months. In osteoblasts, low concentrations of PFOA increased osteocalcin (OCN) expression and calcium secretion, but at PFOA concentrations of 100 μM and above osteocalcin (OCN) expression and calcium secretion were decreased. The number of osteoclasts was increased at all PFOA concentrations tested and resorption activity dose-dependently increased from 0.1–1.0 μM, but decreased at higher concentrations. The results show that PFOA accumulates in bone and is present in bones until the old age. PFOA has the potential to influence bone turnover over a long period of time. Therefore bone is a target tissue for PFOA, and altered bone geometry and mineral density seem to persist throughout the life of the animal. - Highlights: • Bone is a target tissue for PFOA both in vivo and in vitro. • Maternal exposure during pregnancy results in PFOA accumulation in bone of the offspring. • PFOA is present in bones until the old age. • PFOA causes mild alterations in bone morphometry

  16. Effects of developmental exposure to perfluorooctanoic acid (PFOA) on long bone morphology and bone cell differentiation

    International Nuclear Information System (INIS)

    Koskela, A.; Finnilä, M.A.; Korkalainen, M.; Spulber, S.; Koponen, J.; Håkansson, H.; Tuukkanen, J.; Viluksela, M.

    2016-01-01

    Perfluorooctanoic acid (PFOA) is a ubiquitous and persistent environmental chemical, which has been used extensively due to its stability and surface tension-lowering properties. Toxicological effects include induction of neonatal mortality and reproductive toxicity. In this study, pregnant C57BL/6 mice were exposed orally to 0.3 mg PFOA/kg/day throughout pregnancy, and female offspring were studied at the age of 13 or 17 months. Morphometrical and biomechanical properties of femurs and tibias were analyzed with micro-computed tomography and 3-point bending, and bone PFOA concentrations were determined by mass spectrometry. The effects of PFOA on bone cell differentiation were studied in osteoclasts from C57BL/6 mice and in the MC3T3 pre-osteoblast cell line. PFOA exposed mice showed increased femoral periosteal area as well as decreased mineral density of tibias. Biomechanical properties of these bones were not affected. Bone PFOA concentrations were clearly elevated even at the age of 17 months. In osteoblasts, low concentrations of PFOA increased osteocalcin (OCN) expression and calcium secretion, but at PFOA concentrations of 100 μM and above osteocalcin (OCN) expression and calcium secretion were decreased. The number of osteoclasts was increased at all PFOA concentrations tested and resorption activity dose-dependently increased from 0.1–1.0 μM, but decreased at higher concentrations. The results show that PFOA accumulates in bone and is present in bones until the old age. PFOA has the potential to influence bone turnover over a long period of time. Therefore bone is a target tissue for PFOA, and altered bone geometry and mineral density seem to persist throughout the life of the animal. - Highlights: • Bone is a target tissue for PFOA both in vivo and in vitro. • Maternal exposure during pregnancy results in PFOA accumulation in bone of the offspring. • PFOA is present in bones until the old age. • PFOA causes mild alterations in bone morphometry

  17. Uranium's effects on bone integrity

    International Nuclear Information System (INIS)

    Souidi, Maamar; Wade-Gueye, Ndeye Marieme; Manens, Line; Blanchardon, Eric; Aigueperse, Jocelyne

    2018-01-01

    Uranium is a radioactive heavy metal naturally present in the environment. Its recent use in various civilian and military applications sometimes result in its release into the environment. After chronic ingestion, uranium accumulates in various organs, preferentially in bones. Several studies have shown that exposure to high concentrations of uranium affects bone growth. Little is known, however, about the effects of chronic exposure to low doses of uranium on bone, especially when ingested via drinking water, the main route by which the public is exposed to this radionuclide. This study examined the effects of chronic exposure to natural uranium through drinking water on bone integrity and bone turnover. Rats were contaminated with different concentrations of natural uranium (15, 10, and 40 mg / l) for 9 months. A high-resolution three-dimensional microtomography scanner was used for the first time to study uranium's impact on bone metabolism and thus on bone tissue integrity. After nine months of uranium exposure, micro-architecture analysis revealed that the cortical bone diameter of the femoral diaphysis of rats contaminated at a concentration of 40 mg/L of uranium had decreased significantly. In conclusion, our findings that chronic ingestion of uranium at low concentrations affects growth of cortical bone width suggests that it may affect bone strength. These results thus suggest the need to pay special attention to children during chronic low-dose exposure to this radionuclide. (authors)

  18. Heterogeneous structure and its effect on properties and electrochemical behavior of ion-exchange membrane

    Science.gov (United States)

    Ariono, D.; Khoiruddin; Subagjo; Wenten, I. G.

    2017-02-01

    Generally, commercially available ion-exchange membrane (IEM) can be classified into homogeneous and heterogeneous membranes. The classification is based on degree of heterogeneity in membrane structure. It is well known that the heterogeneity greatly affects the properties of IEM, such as conductivity, permselectivity, chemical and mechanical stability. The heterogeneity also influences ionic and electrical current transfer behavior of IEM-based processes during their operation. Therefore, understanding the role of heterogeneity in IEM properties is important to provide preliminary information on their operability and applicability. In this paper, the heterogeneity and its effect on IEM properties are reviewed. Some models for describing the heterogeneity of IEM and methods for characterizing the degree of heterogeneity are discussed. In addition, the influence of heterogeneity on the performance of IEM-based processes and their electrochemical behavior are described.

  19. Interphase thermodynamic bond in heterogeneous alloys: effects on alloy properties

    International Nuclear Information System (INIS)

    Savchenko, A.M.; Konovalov, Yu.V.; Yuferov, O.I.

    2005-01-01

    Inconsistency between a conventional thermodynamic description of alloys as a mechanical mixture of phases and a real alloys state as a common thermodynamic system in which there is a complicated physical-chemical phases interaction has been considered. It is supposed that in heterogeneous alloys (eutectic ones, for instance), so called interphase thermodynamic bond can become apparent due to a partial electron levels splitting under phase interaction. Thermodynamic description of phase equilibrium in alloys is proposed taking into account a thermodynamic bond for the system with phase diagram of eutectic type, and methods of the value of this bond estimation are presented. Experimental evidence (Al-Cu-Si, Al-Si-Mg-Cu, U-Mo + Al) of the effect of interphase thermodynamic bond on temperature and enthalpy of melting of alloys are produced as well as possibility of its effects on alloys electrical conduction, strength, heat and corrosion resistance is substantiated theoretically [ru

  20. Analysis of Surface Heterogeneity Effects with Mesoscale Terrestrial Modeling Platforms

    Science.gov (United States)

    Simmer, C.

    2015-12-01

    An improved understanding of the full variability in the weather and climate system is crucial for reducing the uncertainty in weather forecasting and climate prediction, and to aid policy makers to develop adaptation and mitigation strategies. A yet unknown part of uncertainty in the predictions from the numerical models is caused by the negligence of non-resolved land surface heterogeneity and the sub-surface dynamics and their potential impact on the state of the atmosphere. At the same time, mesoscale numerical models using finer horizontal grid resolution [O(1)km] can suffer from inconsistencies and neglected scale-dependencies in ABL parameterizations and non-resolved effects of integrated surface-subsurface lateral flow at this scale. Our present knowledge suggests large-eddy-simulation (LES) as an eventual solution to overcome the inadequacy of the physical parameterizations in the atmosphere in this transition scale, yet we are constrained by the computational resources, memory management, big-data, when using LES for regional domains. For the present, there is a need for scale-aware parameterizations not only in the atmosphere but also in the land surface and subsurface model components. In this study, we use the recently developed Terrestrial Systems Modeling Platform (TerrSysMP) as a numerical tool to analyze the uncertainty in the simulation of surface exchange fluxes and boundary layer circulations at grid resolutions of the order of 1km, and explore the sensitivity of the atmospheric boundary layer evolution and convective rainfall processes on land surface heterogeneity.

  1. Effects of heterogeneous convergence rate on consensus in opinion dynamics

    Science.gov (United States)

    Huang, Changwei; Dai, Qionglin; Han, Wenchen; Feng, Yuee; Cheng, Hongyan; Li, Haihong

    2018-06-01

    The Deffuant model has attracted much attention in the study of opinion dynamics. Here, we propose a modified version by introducing into the model a heterogeneous convergence rate which is dependent on the opinion difference between interacting agents and a tunable parameter κ. We study the effects of heterogeneous convergence rate on consensus by investigating the probability of complete consensus, the size of the largest opinion cluster, the number of opinion clusters, and the relaxation time. We find that the decrease of the convergence rate is favorable to decreasing the confidence threshold for the population to always reach complete consensus, and there exists optimal κ resulting in the minimal bounded confidence threshold. Moreover, we find that there exists a window before the threshold of confidence in which complete consensus may be reached with a nonzero probability when κ is not too large. We also find that, within a certain confidence range, decreasing the convergence rate will reduce the relaxation time, which is somewhat counterintuitive.

  2. Continuous Trading Dynamically Effectively Complete Market with Heterogeneous Beliefs

    DEFF Research Database (Denmark)

    Qin, Zhenjiang

    on the heterogeneous posterior variance of dividend throughout [0; T). The market populated with many time-additive exponential-utility investors is dynamically effectively complete, if investors are allowed to trade in only two long-lived securities continuously. The underlying mechanism is that these assumptions...... imply that the Pareto efficient individual consumption plans are measurable with respect to the aggregate consumption. Hence, I may not need a dynamically complete market to facilitate a Pareto efficient allocation of consumption, the securities only have to facilitate an allocation which is measurable...... a sufficient statistic for computation of the price of redundant dividend derivative and the equilibrium portfolios. The investors form their Pareto optimal trading strategies as if they intend to dynamically endogenously replicate the value of the dividend derivative....

  3. Effective IPTV channel management method over heterogeneous environments

    Science.gov (United States)

    Joo, Hyunchul; Lee, Dai-boong; Song, Hwangjun

    2007-09-01

    This paper presents an effective IPTV channel management method using SVC (scalable video coding) that considers concurrently both channel zapping time and network utilization. A broadcasting channel is encoded in two-layered bitstream (base-layer channel and enhancement-layer channel) to supply for heterogeneous environments. The proposed algorithm locates only a limited numbers of base-layer channels close to users to reduce the network delay part of channel zapping time and adjusts the length of GOP (group of picture) into each base-layer channel to decrease the video decoding delay part of channel zapping time, which are performed based on user's channel preference information. Finally, the experimental results are provided to show the performance of the proposed schemes.

  4. The effect of chronic alcohol administration on bone mineral content and bone strength in male rats.

    Science.gov (United States)

    Broulík, P D; Vondrová, J; Růzicka, P; Sedlácek, R; Zíma, T

    2010-01-01

    Alcohol use has been identified as a risk factor for the development of osteoporosis. Eight male Wistar rats at two months of age were alcoho-fed (7.6 g 95 % ethanol/kg b.w. per day) to evaluate the effects of long-term administration (three months) of alcohol in drinking water. We have used a dose which is considered to be comparable to a dose of 1 liter of wine or 2.5 liters of 12(°) beer used in male adults daily. The bones were tested mechanically by a three-point bending test in a Mini Bionix (MTS) testing system. The bones from alcohol-fed rats were characterized by a reduction in bone density as well as in ash, calcium and phosphate content. In alcohol-fed rats the reduction in bone mineral density (10 %) was reflected by about 12 % reduction of mechanical strength of femur (158+/-5.5 vs. 178+/-3.2 N/mm(2)). Alcohol significantly altered femoral cortical thickness. In our experiment alcohol itself did not exert any antiandrogenic effect and it did not produce changes in the weight of seminal vesicles. Liver function test (GGT, ALP, AST) did not differ between alcohol-fed rats and control rats. Alcohol-induced bone loss is associated with increased bone resorption and decreased bone formation. These results document the efficacy of alcohol at the dose of 7.6 g 95 % ethanol/kg b.w. to cause bone loss and loss of bone mechanical strength in intact rats. The results of the present study may be interpreted as supporting the hypothesis of alcohol as a risk factor for osteoporosis.

  5. Periosteal Distraction Osteogenesis: An Effective Method for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Danyang Zhao

    2016-01-01

    Full Text Available The treatment of bone defects is challenging and controversial. As a new technology, periosteal distraction osteogenesis (PDO uses the osteogenicity of periosteum, which creates an artificial space between the bone surface and periosteum to generate new bone by gradually expanding the periosteum with no need for corticotomy. Using the newly formed bone of PDO to treat bone defects is effective, which can not only avoid the occurrence of immune-related complications, but also solve the problem of insufficient donor. This review elucidates the availability of PDO in the aspects of mechanisms, devices, strategies, and measures. Moreover, we also focus on the future prospects of PDO and hope that PDO will be applied to the clinical treatment of bone defects in the future.

  6. The effect of radiation sterilization on human transplantable bone

    International Nuclear Information System (INIS)

    Triantafyllou, N.; Karatzas, P.

    1974-11-01

    In order to study the effect of radiation sterilization on human transplantable bones, work was carried out on human and bovine bone tissue samples. Factors causing possible alterations in the mechanical structures of the preserved bone allografts were considered to be deep freezing (-35degC), lyophylization, irradiation, or a combination of lyophylization and irradiation. The latter could be shown to lower the mechanical strength of the bone. Crystal lattice of the bone did not show any alterations in x-ray diffraction pattern, following freeze drying and/or irradiation with doses up to 10 Mrad of gamma radiation. Deterioration in mechanical properties is probably due to damage to the organic phase of the bone matrix

  7. Evaluating the Effect of Virtual Reality Temporal Bone Simulation on Mastoidectomy Performance: A Meta-analysis.

    Science.gov (United States)

    Lui, Justin T; Hoy, Monica Y

    2017-06-01

    Background The increasing prevalence of virtual reality simulation in temporal bone surgery warrants an investigation to assess training effectiveness. Objectives To determine if temporal bone simulator use improves mastoidectomy performance. Data Sources Ovid Medline, Embase, and PubMed databases were systematically searched per the PRISMA guidelines. Review Methods Inclusion criteria were peer-reviewed publications that utilized quantitative data of mastoidectomy performance following the use of a temporal bone simulator. The search was restricted to human studies published in English. Studies were excluded if they were in non-peer-reviewed format, were descriptive in nature, or failed to provide surgical performance outcomes. Meta-analysis calculations were then performed. Results A meta-analysis based on the random-effects model revealed an improvement in overall mastoidectomy performance following training on the temporal bone simulator. A standardized mean difference of 0.87 (95% CI, 0.38-1.35) was generated in the setting of a heterogeneous study population ( I 2 = 64.3%, P virtual reality simulation temporal bone surgery studies, meta-analysis calculations demonstrate an improvement in trainee mastoidectomy performance with virtual simulation training.

  8. Effect of Probiotics Supplementation on Bone Mineral Content and Bone Mass Density

    Directory of Open Access Journals (Sweden)

    Kolsoom Parvaneh

    2014-01-01

    Full Text Available A few studies in animals and a study in humans showed a positive effect of probiotic on bone metabolism and bone mass density. Most of the investigated bacteria were Lactobacillus and Bifidobacterium . The positive results of the probiotics were supported by the high content of dietary calcium and the high amounts of supplemented probiotics. Some of the principal mechanisms include (1 increasing mineral solubility due to production of short chain fatty acids; (2 producing phytase enzyme by bacteria to overcome the effect of mineral depressed by phytate; (3 reducing intestinal inflammation followed by increasing bone mass density; (4 hydrolysing glycoside bond food in the intestines by Lactobacillus and Bifidobacteria. These mechanisms lead to increase bioavailability of the minerals. In conclusion, probiotics showed potential effects on bone metabolism through different mechanisms with outstanding results in the animal model. The results also showed that postmenopausal women who suffered from low bone mass density are potential targets to consume probiotics for increasing mineral bioavailability including calcium and consequently increasing bone mass density.

  9. Effects of multi-deficiencies-diet on bone parameters of peripheral bone in ovariectomized mature rat.

    Directory of Open Access Journals (Sweden)

    Thaqif El Khassawna

    Full Text Available Many postmenopausal women have vitamin D and calcium deficiency. Therefore, vitamin D and calcium supplementation is recommended for all patients with osteopenia and osteoporosis. We used an experimental rat model to test the hypothesis that induction of osteoporosis is more efficiently achieved in peripheral bone through combining ovariectomy with a unique multi-deficiencies diet (vitamin D depletion and deficient calcium, vitamin K and phosphorus. 14-week-old Sprague-Dawley rats served as controls to examine the initial bone status. 11 rats were bilaterally ovariectomized (OVX and fed with multi-deficiencies diet. Three months later the treated group and the Sham group (n = 8 were euthanized. Bone biomechanical competence of the diaphyseal bone was examined on both, tibia and femur. Image analysis was performed on tibia via µCT, and on femur via histological analysis. Lower torsional stiffness indicated inferior mechanical competence of the tibia in 3 month OVX+Diet. Proximal metaphyseal region of the tibia showed a diminished bone tissue portion to total tissue in the µCT despite the increased total area as evaluated in both µCT and histology. Cortical bone showed higher porosity and smaller cross sectional thickness of the tibial diaphysis in the OVX+Diet rats. A lower ALP positive area and elevated serum level of RANKL exhibited the unbalanced cellular interaction in bone remodeling in the OVX+Diet rat after 3 month of treatment. Interestingly, more adipose tissue area in bone marrow indicated an effect of bone loss similar to that observed in osteoporotic patients. Nonetheless, the presence of osteoid and elevated serum level of PTH, BGP and Opn suggest the development of osteomalacia rather than an osteoporosis. As the treatment and fracture management of both osteoporotic and osteomalacia patients are clinically overlapping, this study provides a preclinical animal model to be utilized in local supplementation of minerals, drugs

  10. Effects of multi-deficiencies-diet on bone parameters of peripheral bone in ovariectomized mature rat.

    Science.gov (United States)

    El Khassawna, Thaqif; Böcker, Wolfgang; Govindarajan, Parameswari; Schliefke, Nathalie; Hürter, Britta; Kampschulte, Marian; Schlewitz, Gudrun; Alt, Volker; Lips, Katrin Susanne; Faulenbach, Miriam; Möllmann, Henriette; Zahner, Daniel; Dürselen, Lutz; Ignatius, Anita; Bauer, Natali; Wenisch, Sabine; Langheinrich, Alexander Claus; Schnettler, Reinhard; Heiss, Christian

    2013-01-01

    Many postmenopausal women have vitamin D and calcium deficiency. Therefore, vitamin D and calcium supplementation is recommended for all patients with osteopenia and osteoporosis. We used an experimental rat model to test the hypothesis that induction of osteoporosis is more efficiently achieved in peripheral bone through combining ovariectomy with a unique multi-deficiencies diet (vitamin D depletion and deficient calcium, vitamin K and phosphorus). 14-week-old Sprague-Dawley rats served as controls to examine the initial bone status. 11 rats were bilaterally ovariectomized (OVX) and fed with multi-deficiencies diet. Three months later the treated group and the Sham group (n = 8) were euthanized. Bone biomechanical competence of the diaphyseal bone was examined on both, tibia and femur. Image analysis was performed on tibia via µCT, and on femur via histological analysis. Lower torsional stiffness indicated inferior mechanical competence of the tibia in 3 month OVX+Diet. Proximal metaphyseal region of the tibia showed a diminished bone tissue portion to total tissue in the µCT despite the increased total area as evaluated in both µCT and histology. Cortical bone showed higher porosity and smaller cross sectional thickness of the tibial diaphysis in the OVX+Diet rats. A lower ALP positive area and elevated serum level of RANKL exhibited the unbalanced cellular interaction in bone remodeling in the OVX+Diet rat after 3 month of treatment. Interestingly, more adipose tissue area in bone marrow indicated an effect of bone loss similar to that observed in osteoporotic patients. Nonetheless, the presence of osteoid and elevated serum level of PTH, BGP and Opn suggest the development of osteomalacia rather than an osteoporosis. As the treatment and fracture management of both osteoporotic and osteomalacia patients are clinically overlapping, this study provides a preclinical animal model to be utilized in local supplementation of minerals, drugs and growth factors

  11. The effects of heterogeneities on memory-dependent diffusion

    Science.gov (United States)

    Adib, Farhad; Neogi, P.

    1993-07-01

    Case II diffusion is often seen in glassy polymers, where the mass uptake in sorption is proportional to time t instead of sqrt{t}. A memory dependent diffusion is needed to explain such effects, where the relaxation function used to describe the memory effect has a characteristic time. The ratio of this time to the overall diffusion times is the diffusional Deborah number. Simple models show that case II results when the Deborah number is around one, that is, when the two time scales are comparable. Under investigation are the possible effects of the fact that the glassy polymers are heterogeneous over molecular scales. The averaging form given by DiMarzio and Sanchez has been used to obtain the averaged response. The calculated dynamics of sorption show that whereas case II is still observed, the long term tails change dramatically from the oscillatory to torpid, to chaotic, which are all observed in the experiments. The Deborah number defined here in a self-consistent manner collapses in those cases, but causes no other ill-effects.

  12. The effects of floodplain soil heterogeneity on meander planform shape

    Science.gov (United States)

    Motta, D.; Abad, J. D.; Langendoen, E. J.; GarcíA, M. H.

    2012-09-01

    Past analytical studies of meander planform development have mostly focused on the complexity of the governing equations, i.e., hydrodynamics, and less so on the stream bank resistance to erosion, whose spatial heterogeneity is difficult to describe deterministically. This motivated the use of a Monte Carlo approach to examine the effects of floodplain soils and their distribution on planform development, with the goal of including bank erosion properties in the analysis. Simulated bank erosion rates are controlled by the resistance to hydraulic erosion of the bank soils using an excess shear stress approach. The spatial distribution of critical shear stress across the floodplain is delineated on a rectangular, equidistant grid with varying degrees of variability. The corresponding erodibility coefficient is computed using a field-derived empirical relation. For a randomly disturbed distribution, in which the mean resistance to erosion exponentially increases away from the valley centerline, two relevant parameters are identified: the standard deviation of the critical shear stress distribution, which controls skewness and variability of the channel centerline, and the cross-valley increase in soil resistance, which constrains lateral migration and also affects bend skewness. For a purely random distribution, migrated centerlines exhibit larger variability for increasing spatial scales of floodplain soil heterogeneity. For equal stochastic variability of the corresponding governing parameters, relating meander migration to hydraulic erosion of the bank soils produces more variability and shape complexity than the "classic" bank migration approach of Ikeda et al. (1981), which relates migration rate to excess velocity at the outer bank. Finally, the proposed stochastic approach provides a foundation for estimating a suitable spatial density of measurements to characterize the physical properties of floodplain soils and vegetation.

  13. Effect of epimedium pubescen flavonoid on bone mineral status and bone turnover in male rats chronically exposed to cigarette smoke

    Directory of Open Access Journals (Sweden)

    Gao Shu-guang

    2012-06-01

    Full Text Available Abstract Background Epimedii herba is one of the most frequently used herbs in formulas that are prescribed for the treatment of osteoporosis in China and its main constituent is Epimedium pubescen flavonoid (EPF. However, it is unclear whether EPF during chronic exposure to cigarette smoke may have a protective influence on the skeleton. The present study investigated the effect of EPF on bone mineral status and bone turnover in a rat model of human relatively high exposure to cigarette smoke. Methods Fifty male Wistar rats were randomized into five groups: controls, passive smoking groups and passive smoking rats administered EPF at three dosage levels (75, 150 or 300 mg/kg/day in drinking water for 4 months. A rat model of passive smoking was prepared by breeding male rats in a cigarette-smoking box. Bone mineral content (BMC, bone mineral density (BMD, bone turnover markers, bone histomorphometric parameters and biomechanical properties were examined. Results Smoke exposure decreased BMC and BMD, increased bone turnover (inhibited bone formation and stimulated its resorption, affected bone histomorphometry (increased trabecular separation and osteoclast surface per bone surface; decreased trabecular bone volume, trabecular thickness, trabecular number, cortical thickness, bone formation rate and osteoblast surface per bone surface, and reduced mechanical properties. EPF supplementation during cigarette smoke exposure prevented smoke-induced changes in bone mineral status and bone turnover. Conclusion The results suggest that EPF can prevent the adverse effects of smoke exposure on bone by stimulating bone formation and inhibiting bone turnover and bone resorption.

  14. Experimental study of the effects of radiation on growing bone by bone scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, Hisashi; Sakai, Yasuhiko; Morita, Seiichiro; Bussaka, Yoshitaka; Kikuchi, Shigeru; Okinaga, Toshichika; Oshibuchi, Masao; Umezaki, Noriyoshi

    1987-02-01

    Bones of immature rabbits were irradiated during the growth period, and followed with bone scintigraphy using Tc-99m methylene diphosphonate. The accumulation of the radionuclide was decreased in the irradiated bone at an early period as compared to the control side, and the decrease was more pronounced as the dose of irradiation was increased. In the groups irradiated with less than 4,000 rad, the accumulation ratio reached a minimum at 5 weeks and was followed by a gradual recovery. In the group irradiated with 6,000 rad, the recovery was small; and no recovery was observed in the 8,000 rad group. These changes were compared to the inhibition of the longitudinal growth of the bone. The accumulation ratio for the radionuclide was a more sensitive index of the effect of radiation than the growth rate.

  15. Recommendations on the effect of antidiabetic drugs in bone.

    Science.gov (United States)

    Rozas-Moreno, Pedro; Reyes-García, Rebeca; Jódar-Gimeno, Esteban; Varsavsky, Mariela; Luque-Fernández, Inés; Cortés-Berdonces, María; Muñoz-Torres, Manuel

    2017-03-01

    To provide recommendations on the effect of antidiabetic drugs on bone fragility to help select the most adequate antidiabetic treatment, especially in diabetic patients with high risk of fracture. Members of the Bone Metabolism Working Group of the Spanish Society of Endocrinology. The GRADE system (Grading of Recommendations, Assessment, Development, and Evaluation) was used to establish both the strength of recommendations and the quality of evidence. A systematic search was made in MEDLINE (Pubmed) using the following terms associated to the name of each antidiabetic drug: AND "osteoporosis", "fractures", "bone mineral density", "bone markers", "calciotropic hormones". Papers in English with publication date before 30 April 2016 were reviewed. Recommendations were jointly discussed by the Working Group. The document summaries the data on the potential effects of antidiabetic drugs on bone metabolism and fracture risk. Copyright © 2017 SEEN. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Effect of site-specific heterogeneous evolution on phylogenetic reconstruction: a simple evaluation.

    Science.gov (United States)

    Cheng, Qiqun; Su, Zhixi; Zhong, Yang; Gu, Xun

    2009-07-15

    Recent studies have shown that heterogeneous evolution may mislead phylogenetic analysis, which has been neglected for a long time. We evaluate the effect of heterogeneous evolution on phylogenetic analysis, using 18 fish mitogenomic coding sequences as an example. Using the software DIVERGE, we identify 198 amino acid sites that have experienced heterogeneous evolution. After removing these sites, the rest of sites are shown to be virtually homogeneous in the evolutionary rate. There are some differences between phylogenetic trees built with heterogeneous sites ("before tree") and without heterogeneous sites ("after tree"). Our study demonstrates that for phylogenetic reconstruction, an effective approach is to identify and remove sites with heterogeneous evolution, and suggests that researchers can use the software DIVERGE to remove the influence of heterogeneous evolution before reconstructing phylogenetic trees.

  17. Heterogeneous Effects of Direct Hypoxia Pathway Activation in Kidney Cancer.

    Directory of Open Access Journals (Sweden)

    Rafik Salama

    Full Text Available General activation of hypoxia-inducible factor (HIF pathways is classically associated with adverse prognosis in cancer and has been proposed to contribute to oncogenic drive. In clear cell renal carcinoma (CCRC HIF pathways are upregulated by inactivation of the von-Hippel-Lindau tumor suppressor. However HIF-1α and HIF-2α have contrasting effects on experimental tumor progression. To better understand this paradox we examined pan-genomic patterns of HIF DNA binding and associated gene expression in response to manipulation of HIF-1α and HIF-2α and related the findings to CCRC prognosis. Our findings reveal distinct pan-genomic organization of canonical and non-canonical HIF isoform-specific DNA binding at thousands of sites. Overall associations were observed between HIF-1α-specific binding, and genes associated with favorable prognosis and between HIF-2α-specific binding and adverse prognosis. However within each isoform-specific set, individual gene associations were heterogeneous in sign and magnitude, suggesting that activation of each HIF-α isoform contributes a highly complex mix of pro- and anti-tumorigenic effects.

  18. Giant cell tumor with secondary aneurysmal bone cyst shows heterogeneous metabolic pattern on {sup 18}F-FDG PET.CT: A case reort

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hee Jeong; Kwon, Seong Young; Yoon, Yeon Hong [Chonnam National University Hwasun Hospital, Huasun (Korea, Republic of); Cho, Sang Geon; Kim, Jahae; Song, Ho Chun; Kim, Sung Sun; Park, Jin Gyoon [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2016-12-15

    Giant cell tumor (GCT) is a generally benign bone tumor accounting for approximately 5 % of all primary bone neoplasms. Cystic components in GCTs that indicate secondary aneurysmal bone cysts (ABCs) are reported in 14 % of GCTs. Although both of them have been described separately in previous reports that may show considerable fluorodeoxyglucose (FDG) uptake despite their benign nature, the findings of GCT with secondary ABC on 18F-FDG positron emission tomography/computed tomography (PET/CT) have not been well-known. We report a case of GCT with secondary ABC in a 26-year-old woman. 18F-FDG PET/CT revealed a heterogeneous hypermetabolic lesion in the left proximal femur with the maximum standardized uptake value of 4.7. The solid components of the tumor showed higher FDG uptake than the cystic components. These observations suggest that the ABC components in GCTs show heterogeneous metabolic patterns on {sup 18}F-FDG PET/CT.

  19. Giant cell tumor with secondary aneurysmal bone cyst shows heterogeneous metabolic pattern on "1"8F-FDG PET.CT: A case reort

    International Nuclear Information System (INIS)

    Park, Hee Jeong; Kwon, Seong Young; Yoon, Yeon Hong; Cho, Sang Geon; Kim, Jahae; Song, Ho Chun; Kim, Sung Sun; Park, Jin Gyoon

    2016-01-01

    Giant cell tumor (GCT) is a generally benign bone tumor accounting for approximately 5 % of all primary bone neoplasms. Cystic components in GCTs that indicate secondary aneurysmal bone cysts (ABCs) are reported in 14 % of GCTs. Although both of them have been described separately in previous reports that may show considerable fluorodeoxyglucose (FDG) uptake despite their benign nature, the findings of GCT with secondary ABC on 18F-FDG positron emission tomography/computed tomography (PET/CT) have not been well-known. We report a case of GCT with secondary ABC in a 26-year-old woman. 18F-FDG PET/CT revealed a heterogeneous hypermetabolic lesion in the left proximal femur with the maximum standardized uptake value of 4.7. The solid components of the tumor showed higher FDG uptake than the cystic components. These observations suggest that the ABC components in GCTs show heterogeneous metabolic patterns on "1"8F-FDG PET/CT

  20. Bone effects of biologic drugs in rheumatoid arthritis.

    Science.gov (United States)

    Corrado, Addolorata; Neve, Anna; Maruotti, Nicola; Cantatore, Francesco Paolo

    2013-01-01

    Biologic agents used in the treatment of rheumatoid arthritis (RA) are able to reduce both disease activity and radiographic progression of joint disease. These drugs are directed against several proinflammatory cytokines (TNF α , IL-6, and IL-1) which are involved both in the pathogenesis of chronic inflammation and progression of joint structural damage and in systemic and local bone loss typically observed in RA. However, the role of biologic drugs in preventing bone loss in clinical practice has not yet clearly assessed. Many clinical studies showed a trend to a positive effect of biologic agents in preventing systemic bone loss observed in RA. Although the suppression of inflammation is the main goal in the treatment of RA and the anti-inflammatory effects of biologic drugs exert a positive effect on bone metabolism, the exact relationship between the prevention of bone loss and control of inflammation has not been clearly established, and if the available biologic drugs against TNF α , IL-1, and IL-6 can exert their effect on systemic and local bone loss also through a direct mechanism on bone cell metabolism is still to be clearly defined.

  1. Effects of Heterogeneous Social Interactions on Flocking Dynamics

    Science.gov (United States)

    Miguel, M. Carmen; Parley, Jack T.; Pastor-Satorras, Romualdo

    2018-02-01

    Social relationships characterize the interactions that occur within social species and may have an important impact on collective animal motion. Here, we consider a variation of the standard Vicsek model for collective motion in which interactions are mediated by an empirically motivated scale-free topology that represents a heterogeneous pattern of social contacts. We observe that the degree of order of the model is strongly affected by network heterogeneity: more heterogeneous networks show a more resilient ordered state, while less heterogeneity leads to a more fragile ordered state that can be destroyed by sufficient external noise. Our results challenge the previously accepted equivalence between the static Vicsek model and the equilibrium X Y model on the network of connections, and point towards a possible equivalence with models exhibiting a different symmetry.

  2. The biphasic effect of triiodothyronine compared to bone resorbing effect of PTH on bone modelling of mouse long bone in vitro

    International Nuclear Information System (INIS)

    Soskolne, W.A.; Schwartz, Z.; Goldstein, M.; Ornoy, A.

    1990-01-01

    To examine the effects of T3 on fetal long bone modelling the radii and ulnae of 16 day old fetal mice were grown in vitro for two days. Their growth, mineralization, and resorption were assessed by measuring diaphyseal length, calcium and phosphorus content, hydroxyproline content, and the release of incorporated 45 Ca. The effects of T3 were compared to the effects of 1-34 PTH, a known resorbing agent, on the same system. Devitalized bones were used as a control. The results showed that T3 had a biphasic effect. At high concentrations (10(-5) M-10(-6) M) T3 inhibited the growth of the bones as indicated by their diaphyseal length and hydroxyproline content. Calcium and phosphorus content were significantly decreased while 45 Ca release was increased. Similar effects were also found after the addition of 1-34 PTH to the media. However, T3, at lower concentrations (10(-7) M-10(-9) M), stimulated the growth and calcification of the bones as indicated by an increase in diaphyseal length and the hydroxyproline, calcium, and phosphorus content. 45 Ca release was significantly decreased at these concentrations. Neither T3 nor 1-34 PTH affected devitalized bones in the same system. The results suggest that at physiological concentrations, T3 has a direct, anabolic effect on bone, which may explain its major role in the growth process of various species. At high doses, however, T3 stimulates bone resorption in a way similar to PTH

  3. The effect of soil heterogeneity on ATES performance

    Science.gov (United States)

    Sommer, W.; Rijnaarts, H.; Grotenhuis, T.; van Gaans, P.

    2012-04-01

    Due to an increasing demand for sustainable energy, application of Aquifer Thermal Energy Storage (ATES) is growing rapidly. Large-scale application of ATES is limited by the space that is available in the subsurface. Especially in urban areas, suboptimal performance is expected due to thermal interference between individual wells of a single system, or interference with other ATES systems or groundwater abstractions. To avoid thermal interference there are guidelines on well spacing. However, these guidelines, and also design calculations, are based on the assumption of a homogeneous subsurface, while studies report a standard deviation in logpermeability of 1 to 2 for unconsolidated aquifers (Gelhar, 1993). Such heterogeneity may create preferential pathways, reducing ATES performance due to increased advective heat loss or interference between ATES wells. The role of hydraulic heterogeneity of the subsurface related to ATES performance has received little attention in literature. Previous research shows that even small amounts of heterogeneity can result in considerable uncertainty in the distribution of thermal energy in the subsurface and an increased radius of influence (Ferguson, 2007). This is supported by subsurface temperature measurements around ATES wells, which suggest heterogeneity gives rise to preferential pathways and short-circuiting between ATES wells (Bridger and Allen, 2010). Using 3-dimensional stochastic heat transport modeling, we quantified the influence of heterogeneity on the performance of a doublet well energy storage system. The following key parameters are varied to study their influence on thermal recovery and thermal balance: 1) regional flow velocity, 2) distance between wells and 3) characteristics of the heterogeneity. Results show that heterogeneity at the scale of a doublet ATES system introduces an uncertainty up to 18% in expected thermal recovery. The uncertainty increases with decreasing distance between ATES wells. The

  4. The Mechanical Properties and Biometrical Effect of 3D Preformed Titanium Membrane for Guided Bone Regeneration on Alveolar Bone Defect

    Directory of Open Access Journals (Sweden)

    So-Hyoun Lee

    2017-01-01

    Full Text Available The purpose of this study is to evaluate the effect of three-dimensional preformed titanium membrane (3D-PFTM to enhance mechanical properties and ability of bone regeneration on the peri-implant bone defect. 3D-PFTMs by new mechanically compressive molding technology and manually shaped- (MS- PFTMs by hand manipulation were applied in artificial peri-implant bone defect model for static compressive load test and cyclic fatigue load test. In 12 implants installed in the mandibular of three beagle dogs, six 3D-PFTMs, and six collagen membranes (CM randomly were applied to 2.5 mm peri-implant buccal bone defect with particulate bone graft materials for guided bone regeneration (GBR. The 3D-PFTM group showed about 7.4 times higher mechanical stiffness and 5 times higher fatigue resistance than the MS-PFTM group. The levels of the new bone area (NBA, %, the bone-to-implant contact (BIC, %, distance from the new bone to the old bone (NB-OB, %, and distance from the osseointegration to the old bone (OI-OB, % were significantly higher in the 3D-PFTM group than the CM group (p<.001. It was verified that the 3D-PFTM increased mechanical properties which were effective in supporting the space maintenance ability and stabilizing the particulate bone grafts, which led to highly efficient bone regeneration.

  5. The effect of sympathectomy on bone blood flow in man

    International Nuclear Information System (INIS)

    Lahtinen, T.; Alhava, E.M.; Hyoedynmaa, S.; Hendolin, H.; Oksala, I.

    1982-01-01

    The effect of lumbar sympathectomy on bone blood flow was measured in seven patients with a Xe-133 washout method. On the third postoperative day there was a significant increase of blood flow in the proximal femur and a slight increase in the proximal tibia. Two months after the operation blood flow in the proximal part of the femur was no more significantly increased but in the proximal tibia there was a significant increase. The study suggests that the positive effect of sympathectomy on bone blood flow may be of value in cases where the increase of blood flow to peripheral bones is required

  6. Effects of reservoir heterogeneity on scaling of effective mass transfer coefficient for solute transport

    Science.gov (United States)

    Leung, Juliana Y.; Srinivasan, Sanjay

    2016-09-01

    Modeling transport process at large scale requires proper scale-up of subsurface heterogeneity and an understanding of its interaction with the underlying transport mechanisms. A technique based on volume averaging is applied to quantitatively assess the scaling characteristics of effective mass transfer coefficient in heterogeneous reservoir models. The effective mass transfer coefficient represents the combined contribution from diffusion and dispersion to the transport of non-reactive solute particles within a fluid phase. Although treatment of transport problems with the volume averaging technique has been published in the past, application to geological systems exhibiting realistic spatial variability remains a challenge. Previously, the authors developed a new procedure where results from a fine-scale numerical flow simulation reflecting the full physics of the transport process albeit over a sub-volume of the reservoir are integrated with the volume averaging technique to provide effective description of transport properties. The procedure is extended such that spatial averaging is performed at the local-heterogeneity scale. In this paper, the transport of a passive (non-reactive) solute is simulated on multiple reservoir models exhibiting different patterns of heterogeneities, and the scaling behavior of effective mass transfer coefficient (Keff) is examined and compared. One such set of models exhibit power-law (fractal) characteristics, and the variability of dispersion and Keff with scale is in good agreement with analytical expressions described in the literature. This work offers an insight into the impacts of heterogeneity on the scaling of effective transport parameters. A key finding is that spatial heterogeneity models with similar univariate and bivariate statistics may exhibit different scaling characteristics because of the influence of higher order statistics. More mixing is observed in the channelized models with higher-order continuity. It

  7. The effects of low environmental cadmium exposure on bone density

    Energy Technology Data Exchange (ETDEWEB)

    Trzcinka-Ochocka, M., E-mail: ochocka@imp.lodz.pl [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland); Jakubowski, M. [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland); Szymczak, W. [Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz (Poland); Insitute of Psychology, University of Lodz (Poland); Janasik, B.; Brodzka, R. [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland)

    2010-04-15

    Recent epidemiological data indicate that low environmental exposure to cadmium, as shown by cadmium body burden (Cd-U), is associated with renal dysfunction as well as an increased risk of cadmium-induced bone disorders. The present study was designed to assess the effects of low environmental cadmium exposure, at the level sufficient to induce kidney damage, on bone metabolism and mineral density (BMD). The project was conducted in the area contaminated with cadmium, nearby a zinc smelter located in the region of Poland where heavy industry prevails. The study population comprised 170 women (mean age=39.7; 18-70 years) and 100 men (mean age=31.9; 18-76 years). Urinary and blood cadmium and the markers of renal tubular dysfunction ({beta}{sub 2}M-U RBP, NAG), glomerular dysfunction (Alb-U and {beta}{sub 2}M-S) and bone metabolism markers (BAP-S, CTX-S) as well as forearm BMD, were measured. The results of this study based on simple dose-effect analysis showed the relationship between increasing cadmium concentrations and an increased excretion of renal dysfunction markers and decreasing bone density. However, the results of the multivariate analysis did not indicate the association between exposure to cadmium and decrease in bone density. They showed that the most important factors that have impact on bone density are body weight and age in the female subjects and body weight and calcium excretion in males. Our investigation revealed that the excretion of low molecular weight proteins occurred at a lower level of cadmium exposure than the possible loss of bone mass. It seems that renal tubular markers are the most sensitive and significant indicators of early health effects of cadmium intoxication in the general population. The correlation of urinary cadmium concentration with markers of kidney dysfunction was observed in the absence of significant correlations with bone effects. Our findings did not indicate any effects of environmental cadmium exposure on bone

  8. Size effects on free vibration of heterogeneous beams

    Directory of Open Access Journals (Sweden)

    Hassanati Bahman

    2018-01-01

    Full Text Available In this paper the influence of microstructure on the free vibration of geometrically similar heterogeneous beams with free-free boundary conditions was numerically investigated by detailed finite element analysis (FEA to identify and quantify any effect of beam size on transverse modal frequencies when the microstructural scale is comparable to the overall size. ANSYS Mechanical APDL was used to generate specific unit cells at the microstructural scale comprised of two isotropic materials with different material properties. Unit cell variants containing voids and inclusions were considered. At the macroscopic scale, four beam sizes consisting of one, two, three or four layers of defined unit cells were represented by repeatedly regenerating the unit cell as necessary. In all four beam sizes the aspect ratio was kept constant. Changes to the volume fractions of each material were introduced while keeping the homogenized properties of the beam fixed. The influence of the beam surface morphology on the results was also investigated. The ANSYS results were compared with the analytical results from solution to Timoshenko beam and nonlocal Timoshenko beam as well as numerical results for a Micropolar beam. In nonlocal Timoshenko beams the Eringen’s small length scale coefficients were estimated for some of the studied models. Numerical analyses based on Micropolar theory were carried out to study the modal frequencies and a method was suggested to estimate characteristic length in bending and coupling number via transverse vibration which verifies the use of Micropolar elasticity theory in dynamic analysis.

  9. A newly developed snack effective for enhancing bone volume

    Directory of Open Access Journals (Sweden)

    Hayashi Hidetaka

    2009-07-01

    Full Text Available Abstract Background The incidence of primary osteoporosis is higher in Japan than in USA and European countries. Recently, the importance of preventive medicine has been gradually recognized in the field of orthopaedic surgery with a concept that peak bone mass should be increased in childhood as much as possible for the prevention of osteoporosis. Under such background, we have developed a new bean snack with an aim to improve bone volume loss. In this study, we examined the effects of a newly developed snack on bone volume and density in osteoporosis model mice. Methods Orchiectomy (ORX and ovariectomy (OVX were performed for C57BL/6J mice of twelve-week-old (Jackson Laboratory, Bar Harbar, ME, USA were used in this experiment. We prepared and given three types of powder diet e.g.: normal calcium diet (NCD, Ca: 0.9%, Clea Japan Co., Tokyo, Japan, low calcium diet (LCD, Ca: 0.63%, Clea Japan Co., and special diet (SCD, Ca: 0.9%. Eighteen weeks after surgery, all the animals were sacrified and prepared for histomorphometric analysis to quantify bone density and bone mineral content. Results As a result of histomorphometric examination, SCD was revealed to enhance bone volume irrespective of age and sex. The bone density was increased significantly in osteoporosis model mice fed the newly developmental snack as compared with the control mice. The bone mineral content was also enhanced significantly. These phenomena were revealed in both sexes. Conclusion It is shown that the newly developed bean snack is highly effective for the improvement of bone volume loss irrespective of sex. We demonstrated that newly developmental snack supplements may be a useful preventive measure for Japanese whose bone mineral density values are less than the ideal condition.

  10. Monte Carlo-narrow resonance calculational techniques for treating double-heterogeneity effects

    International Nuclear Information System (INIS)

    Gelbard, E.M.; Chen, I.J.

    1986-01-01

    Reliable methods already exist for computing resonance integrals (RI's) in regular lattices. But lattice structures always contain irregularities. Such effects have been called ''double-heterogeneity'' effects. Two methods for computing double heterogeneity effects on RI's are reviewed and evaluated. 2 refs., 1 tab

  11. Effects of anticonvulsants and inactivity on bone disease in epileptics

    Science.gov (United States)

    Murchison, Lilian E.; Bewsher, P. D.; Chesters, Marion; Gilbert, J.; Catto, G.; Law, Elizabeth; McKay, E.; Ross, H. S.

    1975-01-01

    No significant biochemical or radiological features of vitamin D deficiency were found in groups of juvenile and adult epileptics and control groups of non-epileptic patients in hospitals for the mentally retarded. There was evidence of hepatic enzyme induction in patients on anticonvulsants, in that urinary D-glucaric acid concentration and excretion were raised. No effect was found of prolonged anticonvulsant therapy on bone densitometry, but in children immobility was closely associated with decreased bone density. The evidence suggests that disuse osteoporosis is the major bone disease in these mentally retarded children. PMID:1161672

  12. Effects of Implant-Associated Osteomyelitis on Cefuroxime Bone Pharmacokinetics

    DEFF Research Database (Denmark)

    Tøttrup, Mikkel; Bue, Mats; Koch, Janne

    2016-01-01

    Background: The prolonged antibiotic therapy that is often needed for successful management of osteomyelitis may be related to incomplete penetration of antibiotics into the target site. The objective of this study was to assess the effects of implant-associated osteomyelitis on cefuroxime...... cavity up to MICs of 2 mg/L compared with the other tissues, but the time was shorter for higher MICs.  Conclusions: Cefuroxime penetration into infected cancellous bone was incomplete but comparable with that in healthy bone. The destructive bone processes associated with acute osteomyelitis reduced...

  13. Heterogenization of Homogeneous Catalysts: the Effect of the Support

    Energy Technology Data Exchange (ETDEWEB)

    Earl, W.L.; Ott, K.C.; Hall, K.A.; de Rege, F.M.; Morita, D.K.; Tumas, W.; Brown, G.H.; Broene, R.D.

    1999-06-29

    We have studied the influence of placing a soluble, homogeneous catalyst onto a solid support. We determined that such a 'heterogenized' homogeneous catalyst can have improved activity and selectivity for the asymmetric hydrogenation of enamides to amino acid derivatives. The route of heterogenization of RhDuPhos(COD){sup +} cations occurs via electrostatic interactions with anions that are capable of strong hydrogen bonding to silica surfaces. This is a novel approach to supported catalysis. Supported RhDuPhos(COD){sup +} is a recyclable, non-leaching catalyst in non-polar media. This is one of the few heterogenized catalysts that exhibits improved catalytic performance as compared to its homogeneous analog.

  14. Heterogeneity in Consumer Demands and the Income Effect

    DEFF Research Database (Denmark)

    Christensen, Mette

    2014-01-01

    This paper uses unique Spanish panel data on household expenditures to test whether unobservable heterogeneity in household demands (taste, etc.) is correlated with total expenditures (income). The main finding is that tastes are indeed correlated with income for about half of the goods considere....... For transportation, the bias is sufficiently large to misclassify the good as a luxury.......This paper uses unique Spanish panel data on household expenditures to test whether unobservable heterogeneity in household demands (taste, etc.) is correlated with total expenditures (income). The main finding is that tastes are indeed correlated with income for about half of the goods considered......, implying that cross-sectional estimates of income elasticities for these goods are biased. The goods are the following: food eaten outside home, alcohol and tobacco, transportation, and energy. The elasticity of alcohol and tobacco is more than halved when taking unobserved heterogeneity into account...

  15. EFFECTS OF RUN TRAINING ON BONE DEVELOPMENT AND BONE MINERALIZATION IN GROWING MICE

    Directory of Open Access Journals (Sweden)

    B Gönül

    2011-06-01

    Full Text Available We planned to study the body weights, bone sizes and bone mineral (Ca, Mg, Zn contents of growing mice subjected to treadmill training. Twelve 4-week-old male Swiss Albino mice were divided into sedentary and exercise groups. The mice were trained by running exercise on a flat bed treadmill with 15 m/min, 30 min/day motion, throughout 5 days per week, for 12 weeks. The body weight of animals, and length, fat-free dry weight and Ca, Mg, and Zn contents of bones were measured in both groups. Body weights of animals, and lengths and wet and dry weights of the femur and the tibia were significantly higher in the exercised group. Also, the Zn, Mg and Ca mineral contents of bones in the group that underwent exercise were higher than in the other group. Running exercise with a flat bed treadmill performed by the growing mice is an effective exercise mode, especially for bone morphology.

  16. Effects of implant drilling parameters for pilot and twist drills on temperature rise in bone analog and alveolar bones.

    Science.gov (United States)

    Chen, Yung-Chuan; Hsiao, Chih-Kun; Ciou, Ji-Sih; Tsai, Yi-Jung; Tu, Yuan-Kun

    2016-11-01

    This study concerns the effects of different drilling parameters of pilot drills and twist drills on the temperature rise of alveolar bones during dental implant procedures. The drilling parameters studied here include the feed rate and rotation speed of the drill. The bone temperature distribution was analyzed through experiments and numerical simulations of the drilling process. In this study, a three dimensional (3D) elasto-plastic dynamic finite element model (DFEM) was proposed to investigate the effects of drilling parameters on the bone temperature rise. In addition, the FE model is validated with drilling experiments on artificial human bones and porcine alveolar bones. The results indicate that 3D DFEM can effectively simulate the bone temperature rise during the drilling process. During the drilling process with pilot drills or twist drills, the maximum bone temperature occurred in the region of the cancellous bones close to the cortical bones. The feed rate was one of the important factors affecting the time when the maximum bone temperature occurred. Our results also demonstrate that the elevation of bone temperature was reduced as the feed rate increased and the drill speed decreased, which also effectively reduced the risk region of osteonecrosis. These findings can serve as a reference for dentists in choosing drilling parameters for dental implant surgeries. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  17. Optimum measuring net for correcting mineralizing heterogeneity effect in XRF sampling

    International Nuclear Information System (INIS)

    Zhou Sichun; Zhao Youqing; Zhang Yuhuan

    2000-01-01

    The mineralizing heterogeneity effect in XRF sampling was investigated with theory of mathematical statistics. A method called 'Optimum measuring Net' has been developed. The theoretical estimation and experimental results show that the mineralizing heterogeneity effect can be cut down to the minimum with the method

  18. Effects of treatments for experimental bone tumor on prostaglandin E level and bone scintigrams

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Nobuaki; Ito, Yasuhiko; Yoneda, Masaya; Muranaka, Akira; Nishishita, Soichi; Morita, Rikushi [Kawasaki Medical School, Kurashiki, Okayama (Japan)

    1983-10-01

    The role of Prostaglandin E (PgE) level was studied experimentally as follows: 1) intrahepatic implantation of VX-2, 2) intravenous injection of VX-2, 3) effect of treatments on intramedullary implanted VX-2. The levels of PgE in intrahepatic and intravenous transplantation were not higher than that of intramedullary transplantation. Mitomycin C (MMC) did not reduce the PgE level and appearance time of bone scan abnormality was the same as that of untreated animals. A combination of indomethacin and MMC caused a delay in appearance time of bone scan abnormalities.

  19. Bone turnover in postmenopausal osteoporosis. Effect of calcitonin treatment.

    Science.gov (United States)

    Civitelli, R; Gonnelli, S; Zacchei, F; Bigazzi, S; Vattimo, A; Avioli, L V; Gennari, C

    1988-10-01

    To investigate the effectiveness of calcitonin treatment of postmenopausal osteoporosis in relation to bone turnover, we examined 53 postmenopausal osteoporotic women before and after one year of therapy with salmon calcitonin (sCT), at the dose of 50 IU every other day. Baseline evaluation revealed that 17 (32%) patients had high turnover (HTOP), and 36 (68%) normal turnover osteoporosis (NTOP) as assessed by measurement of whole body retention (WBR) of 99mTc-methylene diphosphonate. The two groups did not differ in terms of bone mineral content (BMC) measured by dual photon absorptiometry at both lumbar spine and femoral diaphysis. However, HTOP patients had higher levels of serum osteocalcin (OC) and urinary hydroxyproline excretion (HOP/Cr). Multivariate regression analysis showed no correlation between parameters of bone turnover (WBR, OC, HOP/Cr) and both femoral and vertebral bone density; the latter being negatively correlated only with the years elapsed since menopause (R2 = 0.406). Treatment with sCT resulted in a significant increase of vertebral BMC in the 53 patients taken as a whole group (+/- 7%, P less than 0.001). When the results obtained in HTOP and NTOP were analyzed separately, only those with HTOP showed a marked increment of spinal BMC (+22%, P less than 0.001), NTOP subjects neither gained nor lost bone mineral during the study. Femoral BMC decreased in the whole group after sCT therapy (-3%, P less than 0.003). However, HTOP patients maintained initial BMC values, whereas those with NTOP lost a significant amount of bone during the study period (-5%, P less than 0.001). The increase of vertebral bone mass was associated with a marked depression of bone turnover detectable in both subsets of patients and in the whole group. (a) assessment of bone turnover cannot help predict the severity of bone loss in postmenopausal osteoporosis; (b) calcitonin therapy appears to be particularly indicated for patients with high-turnover osteoporosis

  20. Biological effect of hydrolyzed collagen on bone metabolism.

    Science.gov (United States)

    Daneault, Audrey; Prawitt, Janne; Fabien Soulé, Véronique; Coxam, Véronique; Wittrant, Yohann

    2017-06-13

    Osteoporosis is a chronic and asymptomatic disease characterized by low bone mass and skeletal microarchitectural deterioration, increased risk of fracture, and associated comorbidities most prevalent in the elderly. Due to an increasingly aging population, osteoporosis has become a major health issue requiring innovative disease management. Proteins are important for bone by providing building blocks and by exerting specific regulatory function. This is why adequate protein intake plays a considerable role in both bone development and bone maintenance. More specifically, since an increase in the overall metabolism of collagen can lead to severe dysfunctions and a more fragile bone matrix and because orally administered collagen can be digested in the gut, cross the intestinal barrier, enter the circulation, and become available for metabolic processes in the target tissues, one may speculate that a collagen-enriched diet provides benefits for the skeleton. Collagen-derived products such as gelatin or hydrolyzed collagen (HC) are well acknowledged for their safety from a nutritional point of view; however, what is their impact on bone biology? In this manuscript, we critically review the evidence from literature for an effect of HC on bone tissues in order to determine whether HC may represent a relevant alternative in the design of future nutritional approaches to manage osteoporosis prevention.

  1. Effects of Cremation on Fetal Bones.

    Science.gov (United States)

    Zana, Michela; Magli, Francesca; Mazzucchi, Alessandra; Castoldi, Elisa; Gibelli, Daniele; Caccia, Giulia; Cornacchia, Francesca; Gaudio, Daniel A; Mattia, Mirko; Cattaneo, Cristina

    2017-09-01

    The charring process is a weak point of anthropological analysis as it changes bone morphology and reduces information obtainable, specially in fetuses. This experiment aims at verifying the conservation of fetal bones after cremation. A total of 3138 fetuses of unknown sex and age were used, deriving from legal and therapeutic abortions from different hospitals of Milan. Cremations took place in modern crematoria. Nine cremation events were analyzed, each ranging from 57 to 915 simultaneously cremated fetuses. During the cremations, 4356 skeletal remains were recovered, 3756 of which (86.2%) were morphologically distinguishable. All types of fetal skeletal elements were found, with the exception of some cranial bones. Only 3.4% of individuals could be detected after the cremation process, because of the prevalence of abortions under 12 lunar weeks. All fire alterations were observed and the results were statistically analyzed. This pilot study confirmed the possibility of preservation of fetal skeletal elements after cremation. © 2017 American Academy of Forensic Sciences.

  2. Effect of Electromagnetic Fields on Transfer Processes in Heterogeneous Systems

    Czech Academy of Sciences Publication Activity Database

    Levdansky, V.V.; Kim, H. Y.; Kim, H. C.; Smolík, Jiří; Moravec, Pavel

    2001-01-01

    Roč. 44, č. 5 (2001), s. 1065-1071 ISSN 0017-9310 Institutional research plan: CEZ:AV0Z4072921 Keywords : electromagnetic field * transfer processes * heterogeneous system Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.240, year: 2001

  3. Effectiveness of Reirradiation for Painful Bone Metastases: A Systematic Review and Meta-Analysis

    International Nuclear Information System (INIS)

    Huisman, Merel; Bosch, Maurice A.A.J. van den; Wijlemans, Joost W.; Vulpen, Marco van; Linden, Yvette M. van der; Verkooijen, Helena M.

    2012-01-01

    Purpose: Reirradiation of painful bone metastases in nonresponders or patients with recurrent pain after initial response is performed in up to 42% of patients initially treated with radiotherapy. Literature on the effect of reirradiation for pain control in those patients is scarce. In this systematic review and meta-analysis, we quantify the effectiveness of reirradiation for achieving pain control in patients with painful bone metastases. Methods and Materials: A free text search was performed to identify eligible studies using the MEDLINE, EMBASE, and the Cochrane Collaboration library electronic databases. After study selection and quality assessment, a pooled estimate was calculated for overall pain response for reirradiation of metastatic bone pain. Results: Our literature search identified 707 titles, of which 10 articles were selected for systematic review and seven entered the meta-analysis. Overall study quality was mediocre. Of the 2,694 patients initially treated for metastatic bone pain, 527 (20%) patients underwent reirradiation. Overall, a pain response after reirradiation was achieved in 58% of patients (pooled overall response rate 0.58, 95% confidence interval = 0.49–0.67). There was a substantial between-study heterogeneity (I 2 = 63.3%, p = 0.01) because of clinical and methodological differences between studies. Conclusions: Reirradiation of painful bone metastases is effective in terms of pain relief for a small majority of patients; approximately 40% of patients do not benefit from reirradiation. Although the validity of results is limited, this meta-analysis provides a comprehensive overview and the most quantitative estimate of reirradiation effectiveness to date.

  4. The effect of nutritional rickets on bone mineral density.

    Science.gov (United States)

    Thacher, Tom D; Fischer, Philip R; Pettifor, John M

    2014-11-01

    Nutritional rickets is caused by impaired mineralization of growing bone. The effect of nutritional rickets on areal bone mineral density (aBMD) has not been established. Our objective was to determine if aBMD is lower in children with active rickets than in healthy control children. We expected that the reduction in aBMD would vary between the radial and ulnar metaphyses near the growth plates and the proximal diaphyses. Case-control study. Primary care outpatient department of a teaching hospital in Jos, Nigeria. Nigerian children with radiographically-confirmed rickets were compared with a reference group of control children without rickets from the same community. Forearm bone density measurements were performed in all children with pDXA. Age, sex, and height-adjusted bone density parameters were compared between children with rickets and control subjects. A total of 264 children with active rickets (ages 13-120 months) and 660 control children (ages 11-123 months) were included. In multivariate analyses controlling for height, age, and gender, rickets was associated with a 4% greater bone area and 7% lower aBMD of the radial and ulnar metaphyses compared with controls (P rickets on the diaphyses of the radius and ulna were more pronounced with an 11% greater bone area, 21% lower aBMD, and 24% lower bone mineral apparent density than controls (P rickets, aBMD values were unrelated to dairy product intake or serum calcium, phosphorus, alkaline phosphatase, or 25-hydroxyvitamin D. Metaphyseal aBMD was positively associated with radiographic severity score, attributed to bone edge detection artifact by densitometry in active rickets. Rickets results in increased bone area and reduced aBMD, which are more pronounced in the diaphyseal than in the metaphyseal regions of the radius and ulna, consistent with secondary hyperparathyroidism, generalized osteoid expansion and impaired mineralization.

  5. Effects of microgravity on rat bone, cartlage and connective tissues

    Science.gov (United States)

    Doty, S.

    1990-01-01

    The response to hypogravity by the skeletal system was originally thought to be the result of a reduction in weight bearing. Thus a reduced rate of new bone formation in the weight-bearing bones was accepted, when found, as an obvious result of hypogravity. However, data on non-weight-bearing tissues have begun to show that other physiological changes can be expected to occur to animals during spaceflight. This overview of the Cosmos 1887 data discusses these results as they pertain to individual bones or tissues because the response seems to depend on the architecture and metabolism of each tissue under study. Various effects were seen in different tissues from the rats flown on Cosmos 1887. The femur showed a reduced bone mineral content but only in the central region of the diaphysis. This same region in the tibia showed changes in the vascularity of bone as well as some osteocytic cell death. The humerus demonstrated reduced morphometric characteristics plus a decrease in mechanical stiffness. Bone mineral crystals did not mature normally as a result of flight, suggesting a defect in the matrix mineralization process. Note that these changes relate directly to the matrix portion of the bone or some function of bone which slowly responds to changes in the environment. However, most cellular functions of bone are rapid responders. The stimulation of osteoblast precursor cells, the osteoblast function in collagen synthesis, a change in the proliferation rate of cells in the epiphyseal growth plate, the synthesis and secretion of osteocalcin, and the movement of water into or out of tissues, are all processes which respond to environmental change. These rapidly responding events produced results from Cosmos 1887 which were frequently quite different from previous space flight data.

  6. [The Effects of Exercising in Childhood on Bone Health.

    Science.gov (United States)

    Imai, Kazuhiro; Iwamoto, Jun; Torii, Suguru; Masujima, Atsushi

    In contemporary Japan, there is a polarizing trend in children who exercise more than 1,800 minutes a week and those who exercise less than 60 minutes a week. Quite a lot of girls in particular hate exercise,and therefore they don't get enough of it. Osteoporosis is a preventable disease from childhood. It is crucial for girls to exercise and to provide appropriate stimulation to bones before menarche, which increases bone mineral content. Exercise and sports in childhood are characterized as the ways to the lifelong prevention strategies against osteoporosis and fractures. It is hoped that all children practice appropriate exercise program based on scientific evidence to promote bone health. In this review article, the effects of exercising in childhood on bone health, and the points to be noted regarding childhood sports are described.

  7. Effects of Spaceflight on Cells of Bone Marrow Origin

    Directory of Open Access Journals (Sweden)

    Engin Özçivici

    2013-03-01

    Full Text Available Once only a subject for science fiction novels, plans for establishing habitation on space stations, the Moon, and distant planets now appear among the short-term goals of space agencies. This article reviews studies that present biomedical issues that appear to challenge humankind for long-term spaceflights. With particularly focus on cells of bone marrow origin, studies involving changes in bone, immune, and red blood cell populations and their functions due to extended weightlessness were reviewed. Furthermore, effects of mechanical disuse on primitive stem cells that reside in the bone marrow were also included in this review. Novel biomedical solutions using space biotechnology will be required in order to achieve the goal of space exploration without compromising the functions of bone marrow, as spaceflight appears to disrupt homeostasis for all given cell types.

  8. Effect of some chemical radioprotectors on mouse bone marrow

    International Nuclear Information System (INIS)

    Lata, Manju; Ghose, A.; Khanna, C.M.

    1993-01-01

    Effect of 5-hydroxy-L-tryptophan (HT), AET and Se on mice bone marrow has been studied by counting bone marrow micronucleated cells and endogenous spleen colony count (CFU-S). Combination of HT and AET used as a radioprotector has not caused any significant variation in any of the parameter studied when administered once, it increases bone marrow micronucleated cells and decreases CFU-S slightly after daily administration for 7 days. The individual constituent of the combination administered singly does not increase micronucleated cell number. Seven consecutive doses of HT+AET and same in combination with Se enhances micronucleated cells to a higher level. Daily injection of Se alone up to 7 days also causes an increase in micronucleated cells up to same level. CFU-S pool does not show any significant change in number of bone marrow cells through out the study except in the groups where animals were treated with Se. (author). 15 refs., 3 tabs

  9. Research on the Effects of Heterogeneity on Pedestrian Dynamics in Walkway of Subway Station

    Directory of Open Access Journals (Sweden)

    Haoling Wu

    2016-01-01

    Full Text Available The major objective of this paper is to study the effects of heterogeneity on pedestrian dynamics in walkway of subway station. We analyze the observed data of the selected facility and find that walking speed and occupied space were varied in the population. In reality, pedestrians are heterogeneous individuals with different attributes. However, the research on how the heterogeneity affects the pedestrian dynamics in facilities of subway stations is insufficient. The improved floor field model is therefore presented to explore the effects of heterogeneity. Pedestrians are classified into pedestrians walking in pairs, fast pedestrians, and ordinary pedestrians. For convenience, they are denoted as P-pedestrians, F-pedestrians, and O-pedestrians, respectively. The proposed model is validated under homogeneous and heterogeneous conditions. Three pedestrian compositions are simulated to analyze the effects of heterogeneity on pedestrian dynamics. The results show that P-pedestrians have negative effect and F-pedestrians have positive effect. All of the results in this paper indicate that the capacity of walkway is not a constant value. It changes with different component proportions of heterogeneous pedestrians. The heterogeneity of pedestrian has an important influence on the pedestrian dynamics in the walkway of the subway station.

  10. Effect of the “protein diet” and bone tissue.

    Science.gov (United States)

    Nascimento da Silva, Zoraide; Azevedo de Jesuz, Vanessa; De Salvo Castro, Eduardo; Soares da Costa, Carlos Alberto; Teles Boaventura, Gilson; Blondet de Azeredo, Vilma

    2014-01-01

    The aim of this study is to evaluate the effect of the hyperproteic diet consumption on bone tissue. The study was conducted during sixty days. Twenty eight Wistar albinus rats, adults, originated from Laboratory of Experimental Nutrition were divided in four groups: (n = 7); Control 1 (C1), Control 2 (C2), Hyperproteic 1 (HP1) e Hyperproteic 2 (HP2). The C2 and HP2 groups were submitted to 30% of food restriction. The hyperproteic diet was based on the Atkins diet and prepared to simulate the protein diet. At the end of the study the animals were anesthetized to performer bone densitometry analyses by DEXA and blood and tissue collection. Serum and bone minerals analyses were conducted by colorimetric methods in automated equipment. The total bone mineral density (BMD) of the pelvis and the spine of the food restriction groups (HP2 e C2) were lower (p hyperproteic groups (HP1 e HP2). It was observed similar effect on the osteocalcin level, that presented lower (p hyperproteic groups. The insulin level was lower only in HP2 and serum calcium of the HP1 and HP2 groups was lower than C1. The protein diet promotes significant bone change on femur and in the hormones levels related to bone synthesis and maintenance of this tissue.

  11. Estimation of the advection effects induced by surface heterogeneities in the surface energy budget

    NARCIS (Netherlands)

    Cuxart, J.; Wrenger, B.; Martinez-Villagrasa, D.; Reuder, J.; Jonassen, M.O.; Jimenez, M.A.; Lothon, M.; Hartogensis, O.K.; Dunnermann, J.; Conangla, L.; Garai, A.

    2016-01-01

    The effect of terrain heterogeneities in one-point
    measurements is a continuous subject of discussion. Here
    we focus on the order of magnitude of the advection term
    in the equation of the evolution of temperature as generated
    by documented terrain heterogeneities and we estimate

  12. Price Competition in Two-Sided Markets with Heterogeneous Consumers and Network Effects

    NARCIS (Netherlands)

    Filistrucchi, L.; Klein, T.J.

    We model a two-sided market with heterogeneous customers and two heterogeneous network effects. In our model, customers on each market side care differently about both the number and the type of customers on the other side. Examples of two-sided markets are online platforms or daily newspapers. In

  13. Effect of edema, relative biological effectiveness, and dose heterogeneity on prostate brachytherapy

    International Nuclear Information System (INIS)

    Wang, Jian Z.; Mayr, Nina A.; Nag, Subir; Montebello, Joseph; Gupta, Nilendu; Samsami, Nina; Kanellitsas, Christos

    2006-01-01

    Many factors influence response in low-dose-rate (LDR) brachytherapy of prostate cancer. Among them, edema, relative biological effectiveness (RBE), and dose heterogeneity have not been fully modeled previously. In this work, the generalized linear-quadratic (LQ) model, extended to account for the effects of edema, RBE, and dose heterogeneity, was used to assess these factors and their combination effect. Published clinical data have shown that prostate edema after seed implant has a magnitude (ratio of post- to preimplant volume) of 1.3-2.0 and resolves exponentially with a half-life of 4-25 days over the duration of the implant dose delivery. Based on these parameters and a representative dose-volume histogram (DVH), we investigated the influence of edema on the implant dose distribution. The LQ parameters (α=0.15 Gy -1 and α/β=3.1 Gy) determined in earlier studies were used to calculate the equivalent uniform dose in 2 Gy fractions (EUD 2 ) with respect to three effects: edema, RBE, and dose heterogeneity for 125 I and 103 Pd implants. The EUD 2 analysis shows a negative effect of edema and dose heterogeneity on tumor cell killing because the prostate edema degrades the dose coverage to tumor target. For the representative DVH, the V 100 (volume covered by 100% of prescription dose) decreases from 93% to 91% and 86%, and the D 90 (dose covering 90% of target volume) decrease from 107% to 102% and 94% of prescription dose for 125 I and 103 Pd implants, respectively. Conversely, the RBE effect of LDR brachytherapy [versus external-beam radiotherapy (EBRT) and high-dose-rate (HDR) brachytherapy] enhances dose effect on tumor cell kill. In order to balance the negative effects of edema and dose heterogeneity, the RBE of prostate brachytherapy was determined to be approximately 1.2-1.4 for 125 I and 1.3-1.6 for 103 Pd implants. These RBE values are consistent with the RBE data published in the literature. These results may explain why in earlier modeling studies

  14. The effect of Hydroxyapatite/collagen I composites, bone marrow aspirate and bone graft on fixation of bone implants in sheep

    DEFF Research Database (Denmark)

    Babiker, Hassan

      The effect of Hydroxyapatite/collagen I composites, bone marrow aspirate and bone graft on fixation of bone implants IN SHEEP   Ph.D. Student, Hassan Babiker; Associate Professor, Ph.D. Ming Ding; Professor, dr.med., Soren Overgaard. Department of Orthopaedic Surgery, Odense University Hospital......, Odense, Denmark   Background: Hydroxyapatite and collagen composites (HA/coll) have the potential in mimicking and replacing skeletal bones. This study attempted to determine the effect of newly developed HA/coll-composites with and without bone marrow aspirate (BMA) in order to enhance the fixation...... of bone implants.   Materials and Methods: Titanium alloy implants were inserted into bilateral femoral condyles of 8 skeletally mature sheep, four in each sheep. The implant has a circumferential gap of 2 mm. The gap was filled with: HA/coll; HA/coll-BMA; autograft or allograft. Allograft was served...

  15. Dynamic effects of increasing heterogeneity in financial markets

    International Nuclear Information System (INIS)

    Naimzada, Ahmad K.; Ricchiuti, Giorgio

    2009-01-01

    Despite canonical behavioural financial market models [Day R, Huang W. Bulls, bears and market sheep. J Econ Behav Org 1990;14:299-329], that use different types of agents (i.e., fundamentalist vs. chartists), we develop a model in which the source of instability is the interaction of groups that are homogeneous in the strategy they use, but have heterogeneous beliefs about the fundamental value of the asset. Specifically, heterogeneity arises among two groups of fundamentalists that follow gurus. We show that an increasing distance between beliefs (the degree of heterogeneity), leads first (i) to a pitchfork bifurcation to arise secondly (ii) it generates, together with a larger reaction to misalignment of both market maker and agents, the appearance of a periodic, or even, chaotic, price fluctuation; (iii) finally a homoclinic bifurcation [Dieci R, Bischi GI, Gardini L. From bi-stability to chaotic oscillations in a macroeconomic model. Chaos, Solitons and Fractals 2001;12:805-22] transforms a two piece chaotic set into a one piece chaotic set that generates bull and bear markets.

  16. Effects of soil nutrient heterogeneity on intraspecific competition in the invasive, clonal plant Alternanthera philoxeroides.

    Science.gov (United States)

    Zhou, Jian; Dong, Bi-Cheng; Alpert, Peter; Li, Hong-Li; Zhang, Ming-Xiang; Lei, Guang-Chun; Yu, Fei-Hai

    2012-03-01

    Fine-scale, spatial heterogeneity in soil nutrient availability can increase the growth of individual plants, the productivity of plant communities and interspecific competition. If this is due to the ability of plants to concentrate their roots where nutrient levels are high, then nutrient heterogeneity should have little effect on intraspecific competition, especially when there are no genotypic differences between individuals in root plasticity. We tested this hypothesis in a widespread, clonal species in which individual plants are known to respond to nutrient heterogeneity. Plants derived from a single clone of Alternanthera philoxeroides were grown in the greenhouse at low or high density (four or 16 plants per 27·5 × 27·5-cm container) with homogeneous or heterogeneous availability of soil nutrients, keeping total nutrient availability per container constant. After 9 weeks, measurements of size, dry mass and morphology were taken. Plants grew more in the heterogeneous than in the homogeneous treatment, showing that heterogeneity promoted performance; they grew less in the high- than in the low-density treatment, showing that plants competed. There was no interactive effect of nutrient heterogeneity and plant density, supporting the hypothesis that heterogeneity does not affect intraspecific competition in the absence of genotypic differences in plasticity. Treatments did not affect morphological characteristics such as specific leaf area or root/shoot ratio. Results indicate that fine-scale, spatial heterogeneity in the availability of soil nutrients does not increase competition when plants are genetically identical, consistent with the suggestion that effects of heterogeneity on competition depend upon differences in plasticity between individuals. Heterogeneity is only likely to increase the spread of monoclonal, invasive populations such as that of A. philoxeroides in China.

  17. Effect of chemical and physical heterogeneities on colloid-facilitated cesium transport

    Science.gov (United States)

    Rod, Kenton; Um, Wooyong; Chun, Jaehun; Wu, Ning; Yin, Xialong; Wang, Guohui; Neeves, Keith

    2018-06-01

    A set of column experiments was conducted to investigate the chemical and physical heterogeneity effect on colloid facilitated transport under slow pore velocity conditions. Pore velocities were kept below 100 cm d-1 for all experiments. Glass beads were packed into columns establishing four different conditions: 1) homogeneous, 2) mixed physical heterogeneity, 3) sequentially layered physical heterogeneity, and 4) chemical heterogeneity. The homogeneous column was packed with glass beads (diameter 500-600 μm), and physical heterogeneities were created by sequential layering or mixing two sizes of glass bead (500-600 μm and 300-400 μm). A chemical heterogeneity was created using 25% of the glass beads coated with hydrophobic molecules (1H-1H-2H-2H-perfluorooctyltrichlorosilane) mixed with 75% pristine glass beads (all 500-600 μm). Input solution with 0.5 mM CsI and 50 mg L-1 colloids (1-μm diameter SiO2) was pulsed into columns under saturated conditions. The physical heterogeneity in the packed glass beads retarded the transport of colloids compared to homogeneous (R = 25.0), but showed only slight differences between sequentially layered (R = 60.7) and mixed heterogeneity(R = 62.4). The column with the chemical, hydrophobic/hydrophilic, heterogeneity removed most of the colloids from the input solution. All column conditions stripped Cs from colloids onto the column matrix of packed glass beads.

  18. Effect of risedronate on bone in renal transplant recipients.

    Science.gov (United States)

    Coco, Maria; Pullman, James; Cohen, Hillel W; Lee, Sally; Shapiro, Craig; Solorzano, Clemencia; Greenstein, Stuart; Glicklich, Daniel

    2012-08-01

    Bisphosphonates may prevent or treat the bone loss promoted by the immunosuppressive regimens used in renal transplantation. Risedronate is a commonly used third-generation amino-bisphosphonate, but little is known about its effects on the bone health of renal transplant recipients. We randomly assigned 42 new living-donor kidney recipients to either 35 mg of risedronate weekly or placebo for 12 months. We obtained bone biopsies at the time of renal transplant and after 12 months of protocol treatment. Treatment with risedronate did not affect bone mineral density (BMD) in the overall cohort. In subgroup analyses, it tended to preserve BMD in female participants but did not significantly affect the BMD of male participants. Risedronate did associate with increased osteoid volume and trabecular thickness in male participants, however. There was no evidence for the development of adynamic bone disease. In summary, further study is needed before the use of prophylactic bisphosphonates to attenuate bone loss can be recommended in renal transplant recipients.

  19. Calculation code of heterogeneity effects for analysis of small sample reactivity worth

    International Nuclear Information System (INIS)

    Okajima, Shigeaki; Mukaiyama, Takehiko; Maeda, Akio.

    1988-03-01

    The discrepancy between experimental and calculated central reactivity worths has been one of the most significant interests for the analysis of fast reactor critical experiment. Two effects have been pointed out so as to be taken into account in the calculation as the possible cause of the discrepancy; one is the local heterogeneity effect which is associated with the measurement geometry, the other is the heterogeneity effect on the distribution of the intracell adjoint flux. In order to evaluate these effects in the analysis of FCA actinide sample reactivity worth the calculation code based on the collision probability method was developed. The code can handle the sample size effect which is one of the local heterogeneity effects and also the intracell adjoint heterogeneity effect. (author)

  20. Effect of alpha-calciferol on bone mineral density, bone histomorphometry and bone biomechanics in rats by radiative injury to kidney

    International Nuclear Information System (INIS)

    Zhu Feipeng; Wang Hongfu; Gao Linfeng; Jin Weifang

    2003-01-01

    The work is to study the effects of alpha-calciferol on bone mineral density, histomorphometry and biomechanics in rats with osteoporosis induced by irradiation of the rat kidney. 32 male SD rats of six months in age were randomly divided into 4 groups (8 rats per group), i.e. the model group, the sham group, the bone one group and the fosamax group. Osteoporosis was developed in the rats by irradiating the kidney. Then the rats were administrated orally as follows in a 90 days, 0.1 g·kg -1 BW.d of alpha-calciferol for the bone one group, 10 mg·kg -1 BW.d of alendronate sodium in 1 mL CMC for the fosamax group, and 1 mL CMC for both the model group and sham group. BMD of L1-4, bone histomorphometry and the bone biomechanical properties were measured. Compared with the model group, both the bone one group and the fosamax group were characterized with significantly higher BMD of L1-4 (p<0.01), significantly larger volume and width of bone trabecula, smaller space of bone trabecula (p<0.05, p<0.01), and significantly larger maximal stress of femur and lumbar vertebra (p<0.05, p<0.01). It is concluded that Alpha-calciferol can improve BMD, bone histomorphometry and bone biomechanical properties in rat osteoporosis induced by kidney irradiation

  1. The effect of platelet rich plasma from bone marrow aspirate with added bone morphogenetic protein-2 on the Achilles tendon-bone junction in rabbits.

    Science.gov (United States)

    Kim, Hak Jun; Nam, Hyok-Woo; Hur, Chang-Yong; Park, Misu; Yang, Hee Seok; Kim, Byung-Soo; Park, Jung-Ho

    2011-12-01

    To determine if exogenously injected bone marrow derived platelet-rich plasma (PRP) plus bone morphogenetic protein (BMP)-2 could accelerate the healing of bone-tendon junction injuries and increase the junction holding strength during the early regeneration period. A direct injury model of the bone-tendon junction was made using an Achilles tendon-calcaneus bone junction in a rabbit. In the PRP/BMP-2/fibrin group, 0.05 mL of bone marrow derived PRP and 100 ng/mL of BMP-2 both incorporated into 0.1 mL of fibrin glue were injected into Achilles tendon-calcaneus bone junctions. The effect of the intervention was tested by comparing the results of an intervention group to a control group. The results of biomechanical testing, and histological and gross analyses were compared between the 2 groups at the following time points after surgery: 2 weeks, 4 weeks, and 8 weeks. Histologic examinations showed that woven bone developed in tendon-bone junctions at 2 weeks after surgery in the PRP/BMP-2/fibrin group. Mechanical test results showed no significant difference between the PRP/BMP-2/fibrin and control groups at 2 and 4 weeks after surgery, but the mean maximal load in the PRP/BMP-2/fibrin group was significantly higher than in the control group (p rabbit model of tendon-bone junction injury.

  2. Monte Carlo simulation of the Leksell Gamma Knife{sup TM}: II. Effects of heterogeneous versus homogeneous media for stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Moskvin, Vadim; Timmerman, Robert; DesRosiers, Colleen; Randall, Marcus; DesRosiers, Paul; Dittmer, Phil; Papiez, Lech [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, 535 Barnhill Dr, RT041, IN 46202-5289 (United States)

    2004-11-07

    The absence of electronic equilibrium in the vicinity of bone-tissue or air-tissue heterogeneity in the head can misrepresent deposited dose with treatment planning algorithms that assume all treatment volume as homogeneous media. In this paper, Monte Carlo simulation (PENELOPE) and measurements with a specially designed heterogeneous phantom were applied to investigate the effect of air-tissue and bone-tissue heterogeneity on dose perturbation with the Leksell Gamma Knife{sup TM}. The dose fall-off near the air-tissue interface caused by secondary electron disequilibrium leads to overestimation of dose by the vendor supplied treatment planning software (GammaPlan{sup TM}) at up to 4 mm from an interface. The dose delivered to the target area away from an air-tissue interface may be underestimated by up to 7% by GammaPlan{sup TM} due to overestimation of attenuation of photon beams passing through air cavities. While the underdosing near the air-tissue interface cannot be eliminated with any plug pattern, the overdosage due to under-attenuation of the photon beams in air cavities can be eliminated by plugging the sources whose beams intersect the air cavity. Little perturbation was observed next to bone-tissue interfaces. Monte Carlo results were confirmed by measurements. This study shows that the employed Monte Carlo treatment planning is more accurate for precise dosimetry of stereotactic radiosurgery with the Leksell Gamma Knife{sup TM} for targets in the vicinity of air-filled cavities.

  3. Effect of Physical Forces on the Metastatic Bone Microenvironment

    Science.gov (United States)

    2014-12-01

    gravitational loading does not account for the skeletal effect of botulinum toxin -induced muscle inhibition suggesting a direct effect of muscle on bone...osteoblastic properties . Cancer Res 47:4961– 4966. Schmidt AF, Nielen M, Klungel OH, Hoes AW, de Boer A, Groenwold RH, Kirpensteijn J. 2013. Prognostic

  4. Effect of reservoir heterogeneity on air injection performance in a light oil reservoir

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2018-03-01

    Full Text Available Air injection is a good option to development light oil reservoir. As well-known that, reservoir heterogeneity has great effect for various EOR processes. This also applies to air injection. However, oil recovery mechanisms and physical processes for air injection in heterogeneous reservoir with dip angle are still not well understood. The reported setting of reservoir heterogeneous for physical model or simulation model of air injection only simply uses different-layer permeability of porous media. In practice, reservoir heterogeneity follows the principle of geostatistics. How much of contrast in permeability actually challenges the air injection in light oil reservoir? This should be investigated by using layered porous medial settings of the classical Dykstra-Parsons style. Unfortunately, there has been no work addressing this issue for air injection in light oil reservoir. In this paper, Reservoir heterogeneity is quantified based on the use of different reservoir permeability distribution according to classical Dykstra-Parsons coefficients method. The aim of this work is to investigate the effect of reservoir heterogeneity on physical process and production performance of air injection in light oil reservoir through numerical reservoir simulation approach. The basic model is calibrated based on previous study. Total eleven pseudo compounders are included in this model and ten complexity of reactions are proposed to achieve the reaction scheme. Results show that oil recovery factor is decreased with the increasing of reservoir heterogeneity both for air and N2 injection from updip location, which is against the working behavior of air injection from updip location. Reservoir heterogeneity sometimes can act as positive effect to improve sweep efficiency as well as enhance production performance for air injection. High O2 content air injection can benefit oil recovery factor, also lead to early O2 breakthrough in heterogeneous reservoir. Well

  5. Murine bone marrow Lin⁻Sca⁻1⁺CD45⁻ very small embryonic-like (VSEL cells are heterogeneous population lacking Oct-4A expression.

    Directory of Open Access Journals (Sweden)

    Krzysztof Szade

    Full Text Available Murine very small embryonic-like (VSEL cells, defined by the Lin(-Sca-1(+CD45(- phenotype and small size, were described as pluripotent cells and proposed to be the most primitive hematopoietic precursors in adult bone marrow. Although their isolation and potential application rely entirely on flow cytometry, the immunophenotype of VSELs has not been extensively characterized. Our aim was to analyze the possible heterogeneity of Lin(-Sca(+CD45(- population and investigate the extent to which VSELs characteristics may overlap with that of hematopoietic stem cells (HSCs or endothelial progenitor cells (EPCs. The study evidenced that murine Lin(-Sca-1(+CD45(- population was heterogeneous in terms of c-Kit and KDR expression. Accordingly, the c-Kit(+KDR(-, c-Kit(-KDR(+, and c-Kit(-KDR(- subpopulations could be distinguished, while c-Kit(+KDR(+ events were very rare. The c-Kit(+KDR(- subset contained almost solely small cells, meeting the size criterion of VSELs, in contrast to relatively bigger c-Kit(-KDR(+ cells. The c-Kit(-KDR(-FSC(low subset was highly enriched in Annexin V-positive, apoptotic cells, hence omitted from further analysis. Importantly, using qRT-PCR, we evidenced lack of Oct-4A and Oct-4B mRNA expression either in whole adult murine bone marrow or in the sorted of Lin(-Sca-1(+CD45(-FSC(low population, even by single-cell qRT-PCR. We also found that the Lin(-Sca-1(+CD45(-c-Kit(+ subset did not exhibit hematopoietic potential in a single cell-derived colony in vitro assay, although it comprised the Sca-1(+c-Kit(+Lin(- (SKL CD34(-CD45(-CD105(+ cells, expressing particular HSC markers. Co-culture of Lin(-Sca-1(+CD45(-FSC(low with OP9 cells did not induce hematopoietic potential. Further investigation revealed that SKL CD45(-CD105(+ subset consisted of early apoptotic cells with fragmented chromatin, and could be contaminated with nuclei expelled from erythroblasts. Concluding, murine bone marrow Lin(-Sca-1(+CD45(-FSC(low cells are

  6. Protective Effects of Selected Botanical Agents on Bone

    Directory of Open Access Journals (Sweden)

    James Jam Jolly

    2018-05-01

    Full Text Available Osteoporosis is a serious health problem affecting more than 200 million elderly people worldwide. The early symptoms of this disease are hardly detectable. It causes progressive bone loss, which ultimately renders the patients susceptible to fractures. Osteoporosis must be prevented because the associated fragility fractures result in high morbidity, mortality, and healthcare costs. Many plants used in herbal medicine contain bioactive compounds possessing skeletal protective effects. This paper explores the anti-osteoporotic properties of selected herbal plants, including their actions on osteoblasts (bone forming cells, osteoclasts (bone resorbing cells, and bone remodelling. Some of the herbal plant families included in this review are Berberidaceae, Fabaceae, Arecaceae, Labiatae, Simaroubaceaea, and Myrsinaceae. Their active constituents, mechanisms of action, and pharmaceutical applications were discussed. The literature shows that very few herbal plants have undergone human clinical trials to evaluate their pharmacological effects on bone to date. Therefore, more intensive research should be performed on these plants to validate their anti-osteoporotic properties so that they can complement the currently available conventional drugs in the battle against osteoporosis.

  7. Effect of Rosiglitazone on Radiation Damage in Bone Marrow Hemopoiesis

    International Nuclear Information System (INIS)

    Benko', Klara; Pintye, Eva; Szabo, Boglarka; Geresi, Krisztina; Megyeri, Attila; Benko, Ilona

    2008-01-01

    To study radiobiological effects and drugs, which can modify radiation injury, has an importance if we would like to avoid harmful effects of radiation due to emergency situations or treat patients with malignant diseases by radiotherapy. During the long treatment schedules patients may be treated by not only anticancer but many other drugs because of accompanying diseases. These drugs may also modify radiobiological effects. Rosiglitazone pre-treatment proved to be myeloprotective and accelerated recovery of 5-fluorouracil-damaged bone marrow in our previous experiments. Our new studies are designed to evaluate whether rosiglitazone has similar beneficial effects in radiation-damaged hemopoiesis. Bone marrow damage was precipitated by total body irradiation (TBI) using single increasing doses (2-10 Gy) of γ--irradiation in groups of mice. Lethality was well correlated with damage in hemopoiesis measured by cellularity of bone marrow (LD 50 values were 4.8 and 5.3 gray respectively). Rosiglitazone, an insulin-sensitizing drug, had no significant effect on bone marrow cellularity. Insulin resistance associated with obesity or diabetes mellitus type 2 is intensively growing among cancer patients requiring some kind of radiotherapy. Therefore it is important to know whether drugs used for their therapy can modify radiation effects.

  8. Effect of Rosiglitazone on Radiation Damage in Bone Marrow Hemopoiesis

    Science.gov (United States)

    Benkő, Klára; Pintye, Éva; Szabó, Boglárka; Géresi, Krisztina; Megyeri, Attila; Benkő, Ilona

    2008-12-01

    To study radiobiological effects and drugs, which can modify radiation injury, has an importance if we would like to avoid harmful effects of radiation due to emergency situations or treat patients with malignant diseases by radiotherapy. During the long treatment schedules patients may be treated by not only anticancer but many other drugs because of accompanying diseases. These drugs may also modify radiobiological effects. Rosiglitazone pre-treatment proved to be myeloprotective and accelerated recovery of 5-fluorouracil-damaged bone marrow in our previous experiments. Our new studies are designed to evaluate whether rosiglitazone has similar beneficial effects in radiation-damaged hemopoiesis. Bone marrow damage was precipitated by total body irradiation (TBI) using single increasing doses (2-10 Gy) of γ—irradiation in groups of mice. Lethality was well correlated with damage in hemopoiesis measured by cellularity of bone marrow (LD50 values were 4.8 and 5.3 gray respectively). Rosiglitazone, an insulin-sensitizing drug, had no significant effect on bone marrow cellularity. Insulin resistance associated with obesity or diabetes mellitus type 2 is intensively growing among cancer patients requiring some kind of radiotherapy. Therefore it is important to know whether drugs used for their therapy can modify radiation effects.

  9. Charge Transfer and Support Effects in Heterogeneous Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Hervier, Antoine [Univ. of California, Berkeley, CA (United States)

    2011-12-21

    the band bending at the interface, gives rise to a steady-state flow of hot holes to the surface. This leads to a decrease in turnover on the surface, an effect which is enhanced when a reverse bias is applied to the diode. Similar experiments were carried out for CO oxidation. On Pt/Si diodes, the reaction rate was found to increase when a forward bias was applied. When the diode was exposed to visible light and a reverse bias was applied, the rate was instead decreased. This implies that a flow of negative charges to the surface increases turnover, while positive charges decrease it. Charge flow in an oxide supported metal catalyst can be modified even without designing the catalyst as a solid state electronic device. This was done by doping stoichiometric and nonstoichiometric TiO2 films with F, and using the resulting oxides as supports for Pt films. In the case of stoichiometric TiO2, F was found to act as an n-type dopant, creating a population of filled electronic states just below the conduction band, and dramatically increasing the conductivity of the oxide film. The electrons in those states can transfer to surface O, activating it for reaction with CO, and leading to increased turnover for CO oxidation. This reinforces the hypothesis that CO oxidation is activated by a flow of negative charges to the surface. The same set of catalysts was used for methanol oxidation. The electronic properties of the TiO2 films again correlated with the turnover rates, but also with selectivity. With stoichiometric TiO2 as the support, F-doping caused an increase in selectivity toward the formation of partial oxidation products, formaldehyde and methyl formate, versus the total oxidation product, CO2. With non-stoichiometric TiO2, F-doping had the reverse effect. Ambient Pressure X-Ray Photoelectron Spectroscopy was used to investigate this F-doping effect in reaction conditions. In O2 alone, and in

  10. Array-Enhanced Coherence Resonance: Nontrivial Effects of Heterogeneity and Spatial Independence of Noise

    International Nuclear Information System (INIS)

    Zhou, Changsong; Kurths, Juergen; Hu, Bambi

    2001-01-01

    We demonstrate the effect of coherence resonance in a heterogeneous array of coupled Fitz Hugh--Nagumo neurons. It is shown that coupling of such elements leads to a significantly stronger coherence compared to that of a single element. We report nontrivial effects of parameter heterogeneity and spatial independence of noise on array-enhanced coherence resonance; especially, we find that (i) the coherence increases as spatial correlation of the noise decreases, and (ii) inhomogeneity in the parameters of the array enhances the coherence. Our results have the implication that generic heterogeneity and background noise can play a constructive role to enhance the time precision of firing in neural systems

  11. No effect of Osteoset, a bone graft substitute, on bone healing in humans: a prospective randomized double-blind study

    DEFF Research Database (Denmark)

    Petruskevicius, Juozas; Nielsen, Mette Strange; Kaalund, Søren

    2002-01-01

    We studied the effects of a newly marketed bone substitute, Osteoset, on bone healing in a tibial defect in humans. 20 patients undergoing an ACL (anterior cruciate ligament) reconstruction with bone-patella tendon-bone graft were block-randomized into 2 groups of 10 each. In the treatment group......, the tibial defect was filled manually with Osteoset pellets, in the control group the defect was left empty. CTs of the defect were taken on the first day after the operation, 6 weeks, 3 and 6 months postoperatively. We found about the same amount of bone in the defect in the Osteoset and control groups...... after 6 weeks, 3, and 6 months. In the control group, but not in the Osteoset group, the bone volume increased from 6 weeks to 3 months. The Osteoset pellets were almost resorbed after 6 weeks....

  12. Effect of heterogeneous investments on the evolution of cooperation in spatial public goods game.

    Science.gov (United States)

    Huang, Keke; Wang, Tao; Cheng, Yuan; Zheng, Xiaoping

    2015-01-01

    Understanding the emergence of cooperation in spatial public goods game remains a grand challenge across disciplines. In most previous studies, it is assumed that the investments of all the cooperators are identical, and often equal to 1. However, it is worth mentioning that players are diverse and heterogeneous when choosing actions in the rapidly developing modern society and researchers have shown more interest to the heterogeneity of players recently. For modeling the heterogeneous players without loss of generality, it is assumed in this work that the investment of a cooperator is a random variable with uniform distribution, the mean value of which is equal to 1. The results of extensive numerical simulations convincingly indicate that heterogeneous investments can promote cooperation. Specifically, a large value of the variance of the random variable can decrease the two critical values for the result of behavioral evolution effectively. Moreover, the larger the variance is, the better the promotion effect will be. In addition, this article has discussed the impact of heterogeneous investments when the coevolution of both strategy and investment is taken into account. Comparing the promotion effect of coevolution of strategy and investment with that of strategy imitation only, we can conclude that the coevolution of strategy and investment decreases the asymptotic fraction of cooperators by weakening the heterogeneity of investments, which further demonstrates that heterogeneous investments can promote cooperation in spatial public goods game.

  13. Bone Biomarkers on the Pathway to Effective Spaceflight Countermeasures

    Science.gov (United States)

    Spatz, Jordan

    2009-01-01

    Osteocyte cells are the most abundant yet least understood bone cell type in the human body. However, recent discovers in osteocyte cell biology have shed light on their importance as key mechanosensing cells regulating the bone remodeling process. Thus, we propose the first ever in vitro gene expression evaluation of osteocytes exposed to simulated microgravity to determine mechanistic pathways of their gravity sensing ability. Improved understanding of the fundamental mechanisms at the osteocyte cellular level may lead to improved treatment options to mitigate the effects of bone loss encountered by astronauts on long duration space missions and provide tailored treatment options for maintaining bone strength of immobilized/partially paralyzed patients here on Earth. Aim 1: Characterize the gene expression patterns and protein levels following exposure of murine osteocytelike cell line (MLO-Y4) to simulated microgravity using the NASA Rotating Wall Vessel (RWV) Bioreactor. Osteocytes are theorized to be the mechanosensors and transducers of mechanical load for bones, yet the biological mechanism of this action remains elusive. We propose to investigate the genetic regulation of the mechanism of the MLO-Y4 cell in the NASA Bioreactor as it is the accepted ground-based analog for simulating vector averaged microgravity.

  14. Dietary phosphorus depletion in sheep: Longterm effects on bone structure

    International Nuclear Information System (INIS)

    Breves, G.; Prokop, M.

    1990-01-01

    Experiments were performed on 6 sheep from 8 months old to study effects of dietary phosphorus depletion on bone structure. Sheep were given a semisynthetic diet of chopped straw and pellets for 38 weeks. Mean daily P in the diet was 0.97 g and 3 sheep were given additional NaH2PO4.H2O, increasing daily P supply to 4.5 g (controls). Bone density was estimated photometrically within the laterodistal metaphysis of the foreleg and standardized by a copper step wedge. Metacarpal cortical thickness was also measured. Cortical thickness and bone density started to decrease about 4 weeks after start of P depletion. The trabecular structure of the distal radius was coarser and less dense with reduced cross-linking between trabeculae

  15. Effect of limestone particle size on bone quality characteristics of ...

    African Journals Online (AJOL)

    A study was conducted to determine the effect of different limestone particle sizes in layer diets on bone quality characteristics at end-of-lay hens. Calcitic limestone (360 g Ca/kg DM) that is extensively used in commercial poultry diets was obtained from a specific South African source. Limestone particles were graded as ...

  16. Long term effects of formaldehyde preservation on subsequent bone ...

    African Journals Online (AJOL)

    This study was conducted to compare the effectiveness of cold and hot water maceration techniques for the development of bone specimens from cadavers. Three already dissected bodies of both sexes (two males and a female) obtained from the Department of Anatomy, Bowen University, Iwo, Osun State, Nigeria were ...

  17. Effect of resistance and aerobic exercises on bone mineral density ...

    African Journals Online (AJOL)

    Conclusion: Based on obtained data, it can be concluded that, resistance and aerobic exercise training program is effective in increasing BMD, muscle strength and functional ability in children with hemophilia. Keywords: Hemophilia; Resistance; Aerobic exercise; Bone mineral density; Strength; Functional ability ...

  18. The effect of vitamin D on bone and osteoporosis

    NARCIS (Netherlands)

    Lips, P.T.A.M.; van Schoor, N.M.

    2011-01-01

    The main effect of the active vitamin D metabolite 1,25(OH)2D is to stimulate the absorption of calcium from the gut. The consequences of vitamin D deficiency are secondary hyperparathyroidism and bone loss, leading to osteoporosis and fractures, mineralization defects, which may lead to

  19. MicroCT Bone Densitometry: Context Sensitivity, Beam Hardening Correction and the Effect of Surrounding Media

    Directory of Open Access Journals (Sweden)

    Philip L. Salmon

    2014-12-01

    Full Text Available The context-sensitivity of microCT bone densitometry due to beam hardening artefacts was assessed. Bones and teeth are scanned with varying thickness of surrounding media (water, alcohol, biological tissue and it is important to understand how this affects reconstructed attenuation (“density” of the mineralized tissue. Aluminium tubes and rods with thickness 0.127mm–5mm were scanned both in air or surrounded by up to 2cm of water. Scans were performed with different energy filters and degrees of software beam hardening correction (BHC. Also tested were the effects of signal-to-noise ratio, magnification and truncation. The thickness of an aluminium tube significantly affected its mean reconstructed attenuation. This effect of thickness could be reduced substantially by BHC for scans in air, but not for scans in water. Varying thickness of surrounding water also changed the mean attenuation of an aluminium tube. This artefact could be almost eliminated by an optimal BHC value. The “cupping” artefact of heterogeneous attenuation (elevated at outer surfaces could be corrected if aluminium was scanned in air, but in water BHC was much less effective. Scan truncation, changes to magnification and signal-to-noise ratio also caused artificial changes to measured attenuation. Measurement of bone mineral density by microCT is highly context sensitive. A surrounding layer of liquid or biological tissue reduces the ability of software BHC to remove bone density artefacts. Sample thickness, truncation, magnification and signal to noise ratio also affect reconstructed attenuation. Thus it is important for densitometry that sample and calibration phantom dimensions and mounting materials are standardised.

  20. Effectiveness of Russian current in bone regeneration process in rats

    Directory of Open Access Journals (Sweden)

    Renata Aparecida de Oliveira Lima

    Full Text Available Abstract Introduction: Russian current is an electric current of average frequency that is able to restore the properties of skeletal muscle at a low treatment cost. It is essential to know the effects of Russian current in bone tissue, since electromagnetic energy could be an efficient and low cost method to treat bone disorders. Objective: The aim of the study was to evaluate the effectiveness of Russian current in the consolidation of tibia fracture in adult rats. Methods: 24 adult male Albinus Wistar rats wereused. The animals were divided randomly into two groups: control group (CG, composed of 12 animals, and Intervention Group (IG consisting of 12 animals, both groups were submitted to osteotomy (proximal medial surface of the tibia. The IG underwent an electrical stimulation protocol with Russian current, while the CG did not undergo any kind of intervention. Euthanasia was performed in three animals of each group on the following days: 5, 10, 20, and 30 days of treatment. Results: The results suggested higher primary ossification, intense osteogenic activity, and increased thickness of the periosteum, characterizing more advanced ossification and a greater presence of trabecular bone marrow in rats in the group subjected to the treatment. In this way, we can assign one more beneficial effect to interventions with Russian current, for the treatment of postfracture rehabilitation. Conclusion: In both groups the bone tissue repair process occurred, but in the electrically stimulated group the osteogenesis process was more advanced.

  1. Relationships between in vivo microdamage and the remarkable regional material and strain heterogeneity of cortical bone of adult deer, elk, sheep and horse calcanei

    Science.gov (United States)

    Skedros, John G; Sybrowsky, Christian L; Anderson, Wm Erick; Chow, Frank

    2011-01-01

    Natural loading of the calcanei of deer, elk, sheep and horses produces marked regional differences in prevalent/predominant strain modes: compression in the dorsal cortex, shear in medial–lateral cortices, and tension/shear in the plantar cortex. This consistent non-uniform strain distribution is useful for investigating mechanisms that mediate the development of the remarkable regional material variations of these bones (e.g. collagen orientation, mineralization, remodeling rates and secondary osteon morphotypes, size and population density). Regional differences in strain-mode-specific microdamage prevalence and/or morphology might evoke and sustain the remodeling that produces this material heterogeneity in accordance with local strain characteristics. Adult calcanei from 11 animals of each species (deer, elk, sheep and horses) were transversely sectioned and examined using light and confocal microscopy. With light microscopy, 20 linear microcracks were identified (deer: 10; elk: six; horse: four; sheep: none), and with confocal microscopy substantially more microdamage with typically non-linear morphology was identified (deer: 45; elk: 24; horse: 15; sheep: none). No clear regional patterns of strain-mode-specific microdamage were found in the three species with microdamage. In these species, the highest overall concentrations occurred in the plantar cortex. This might reflect increased susceptibility of microdamage in habitual tension/shear. Absence of detectable microdamage in sheep calcanei may represent the (presumably) relatively greater physical activity of deer, elk and horses. Absence of differences in microdamage prevalence/morphology between dorsal, medial and lateral cortices of these bones, and the general absence of spatial patterns of strain-mode-specific microdamage, might reflect the prior emergence of non-uniform osteon-mediated adaptations that reduce deleterious concentrations of microdamage by the adult stage of bone development. PMID

  2. Nostril Base Augmentation Effect of Alveolar Bone Graft

    Directory of Open Access Journals (Sweden)

    Woojin Lee

    2013-09-01

    Full Text Available Background The aims of alveolar bone grafting are closure of the fistula, stabilization ofthe maxillary arch, support for the roots of the teeth adjacent to the cleft on each side.We observed nostril base augmentation in patients with alveolar clefts after alveolar bonegrafting. The purpose of this study was to evaluate the nostril base augmentation effect ofsecondary alveolar bone grafting in patients with unilateral alveolar cleft.Methods Records of 15 children with alveolar clefts who underwent secondary alveolar bonegrafting with autogenous iliac cancellous bone between March of 2011 and May of 2012 werereviewed. Preoperative and postoperative worm’s-eye view photographs and reconstructedthree-dimensional computed tomography (CT scans were used for photogrammetry. Thedepression of the nostril base and thickness of the philtrum on the cleft side were measuredin comparison to the normal side. The depression of the cleft side pyriform aperture wasmeasured in comparison to the normal side on reconstructed three-dimensional CT.Results Significant changes were seen in the nostril base (P=0.005, the philtrum length(P=0.013, and the angle (P=0.006. The CT measurements showed significant changes in thepyriform aperture (P<0.001 and the angle (P<0.001.Conclusions An alveolar bone graft not only fills the gap in the alveolar process but alsoaugments the nostril base after surgery. In this study, only an alveolar bone graft was performedto prevent bias from other procedures. Nostril base augmentation can be achieved byperforming alveolar bone grafts in children, in whom invasive methods are not advised.

  3. Effects of different loading patterns on the trabecular bone morphology of the proximal femur using adaptive bone remodeling.

    Science.gov (United States)

    Banijamali, S Mohammad Ali; Oftadeh, Ramin; Nazarian, Ara; Goebel, Ruben; Vaziri, Ashkan; Nayeb-Hashemi, Hamid

    2015-01-01

    In this study, the changes in the bone density of human femur model as a result of different loadings were investigated. The model initially consisted of a solid shell representing cortical bone encompassing a cubical network of interconnected rods representing trabecular bone. A computationally efficient program was developed that iteratively changed the structure of trabecular bone by keeping the local stress in the structure within a defined stress range. The stress was controlled by either enhancing existing beam elements or removing beams from the initial trabecular frame structure. Analyses were performed for two cases of homogenous isotropic and transversely isotropic beams.Trabecular bone structure was obtained for three load cases: walking, stair climbing and stumbling without falling. The results indicate that trabecular bone tissue material properties do not have a significant effect on the converged structure of trabecular bone. In addition, as the magnitude of the loads increase, the internal structure becomes denser in critical zones. Loading associated with the stumbling results in the highest density;whereas walking, considered as a routine daily activity, results in the least internal density in different regions. Furthermore, bone volume fraction at the critical regions of the converged structure is in good agreement with previously measured data obtained from combinations of dual X-ray absorptiometry (DXA) and computed tomography (CT). The results indicate that the converged bone architecture consisting of rods and plates are consistent with the natural bone morphology of the femur. The proposed model shows a promising means to understand the effects of different individual loading patterns on the bone density.

  4. Effect of superparamagnetic iron oxide on bone marrow

    International Nuclear Information System (INIS)

    Hundt, W.; Helmberger, T.; Reiser, M.; Petsch, R.

    2000-01-01

    The goal of this study was to compare the effects of SPIO particles on the signal intensity of the bone marrow of the vertebra spine in patients with and without liver cirrhosis. Forty-eight patients with normal liver tissue and 56 patients with liver cirrhosis were examined before and after intravenous SPIO administration, using a 1.5-T system (Magnetom Vision, Siemens, Erlangen, Germany) with a semiflexible cp-array coil. Three different pulse sequences were applied: a T1-weighted gradient-echo sequence, a T2-weighted fast spin-echo sequence with spectral fat suppression and a T2 * -weighted gradient-echo sequence. The signal-to-noise ratio (SNR) of the liver, vertebra bone and paraspinal muscle were obtained. The SNR value change in each patient group and the SNR value difference between the two groups were evaluated. For assessment of statistical significance, Student's t-test with a level of p * -weighted gradient-echo sequence, the signal intensity decrease of the normal liver tissue was approximately -65.6 % (p = 0.00), in cirrhotic liver tissue the decrease was -29.9 % (p = 0.02). The SNR values of the bone marrow showed a decrease of -27.8 % (p = 0.04) in the noncirrhotic liver group, whereas in the cirrhotic liver group it was only -11.3 % and statistically not significant. The effect of SPIO particles on the liver and bone marrow is significantly less in patients with liver cirrhosis. (orig.)

  5. Effects of ovariectomy and cadmium (Cd) on bone calcium

    International Nuclear Information System (INIS)

    Sacco-Gibson, N.; Chaudhry, S.; Abrams, J.; Peterson, D.; Bhattacharyya, M.

    1991-01-01

    This study evaluated the effects of Cd exposure on bone calcium following ovariectomy. Fourteen female beagles (7-9 y old) with 45 Ca prelabeled skeletons (100 μCi/kg body weight) were divided into four groups: shams (SO-; n = 3); ovariectomized (OV-; n =4); shams exposed to Cd (OV+; n = 4). Cd was given in capsules for 4 weeks, increasing dosage weekly (1,5, 15, 50 ppm), followed by exposure for 4.5, 2.0, and 15 weeks in drinking water (15 ppm). Repeated measures of bone mineral density (BMD) were made by dual photon absorptiometry. After the last Cd-water exposure, ribs, tibiae, humerii and lumbar vertebrae (L2-4; L5) were taken from each dog (except SO+, kept for further study). No consistent differences between treatment and control groups were observed in dry or ash weight, Ca content, ash/dry , Ca/dry, and Ca/ash ratios. However, 45 Ca, 45 Ca/dry, and 45 Ca/ash were significantly higher (18 to 38%) in bones of OV+ and OV- compared to SO-. In contrast, significant decreases in BMD of L 2-4 were observed in OV+ dogs (baseline to sacrifice) (OV+: -7.2 ± 1.1%; OV-: -4.0 ± 1.9%; SO-: -1.0 ± 1.7%). Our results suggest: (1) ovariectomy sensitizes bone to cadmium effects and (2) bone mineral loss due to Cd exposure, such as in Itai-Itai disease, may be due to direct effects

  6. Effect of Quercetin on Bone Mineral Status and Markers of Bone Turnover in Retinoic Acid-Induced Osteoporosis

    Directory of Open Access Journals (Sweden)

    Oršolić Nada

    2018-06-01

    Full Text Available Retinoic acid-induced osteoporosis (RBM is one of the most common causes of secondary osteoporosis. This study tested the anti-osteoporetic effect of quercetin in RBM-induced bone loss model (RBM. After 14-day supplementation of 13cRA to induce RBM, rats were administered with quercetin (100 mg/kg or alendronate (40 mg/kg. We analysed changes in body and uterine weight of animals, femoral geometric characteristics, calcium and phosphorus content, bone weight index, bone hystology, bone mineral density (BMD, markers of bone turnover, lipid peroxidation, glutathione levels and SOD, CAT activity of liver, kidney spleen, and ovary as well as biochemical and haematological variables. In comparison to the control RBM rats, the treatment with quercetin increased bone weight index, BMD, osteocalcin level, femoral geometric characteristics, calcium and phosphorus content in the 13cRA-induced bone loss model. Histological results showed its protective action through promotion of bone formation. According to the results, quercetin could be an effective substitution for alendronate in 13cRA-induced osteoporosis. Good therapeutic potential of quercetin on rat skeletal system is based partly on its antioxidant capacity and estrogenic activity.

  7. The effect of radiotherapy, and radiotherapy combined with bisphosphonates or RANK ligand inhibitors on bone quality in bone metastases. A systematic review

    NARCIS (Netherlands)

    Groenen, K.H.J.; Pouw, M.H.; Hannink, G.; Hosman, A.J.; van der Linden, Y.M.; Verdonschot, Nicolaas Jacobus Joseph; Tanck, E.

    2016-01-01

    Purpose The role of radiotherapy in stabilizing metastatic bones is unclear. This systematic review assessed the effects of (1) radiotherapy, (2) radiotherapy combined with bisphosphonates, and (3) radiotherapy combined with RANK ligand (RANKL) inhibitors on bone quality and bone strength in bone

  8. Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tsuneda, H.; Matsukawa, S.; Takayanagi, S.; Matsukawa, M., E-mail: mmatsuka@mail.doshisha.ac.jp [Wave Electronics Research Center, Laboratory of Ultrasonic Electronics, Doshisha University, 1-3, Tatara Miyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Mizuno, K. [Underwater Technology Collaborative Research Center, Institute of Industrial Science, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Yanagitani, T. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso cho, Showa-ku, Nagoya 466-8555 (Japan)

    2015-02-16

    The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurements and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.

  9. The pleiotropic effects of paricalcitol: Beyond bone-mineral metabolism.

    Science.gov (United States)

    Egido, Jesús; Martínez-Castelao, Alberto; Bover, Jordi; Praga, Manuel; Torregrosa, José Vicente; Fernández-Giráldez, Elvira; Solozábal, Carlos

    2016-01-01

    Secondary hyperparathyroidism (SHPT) is a common complication in patients with chronic kidney disease (CKD) that is characterised by elevated parathyroid hormone (PTH) levels and a series of bone-mineral metabolism anomalies. In patients with SHPT, treatment with paricalcitol, a selective vitamin D receptor activator, has been shown to reduce PTH levels with minimal serum calcium and phosphorus variations. The classic effect of paricalcitol is that of a mediator in mineral and bone homeostasis. However, recent studies have suggested that the benefits of treatment with paricalcitol go beyond PTH reduction and, for instance, it has a positive effect on cardiovascular disease and survival. The objective of this study is to review the most significant studies on the so-called pleiotropic effects of paricalcitol treatment in patients with CKD. Copyright © 2015 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  10. Expanding the Description of Spaceflight Effects beyond Bone Mineral Density [BMD]: Trabecular Bone Score [TBS] in ISS Astronauts

    Science.gov (United States)

    Sibonga, J. D.; Spector, E. R.; King, L. J.; Evans, H. J.; Smith, S. A.

    2014-01-01

    Dual-energy x-ray absorptiometry [DXA] is the widely-applied bone densitometry method used to diagnose osteoporosis in a terrestrial population known to be at risk for age-related bone loss. This medical test, which measures areal bone mineral density [aBMD] of clinically-relevant skeletal sites (e.g., hip and spine), helps the clinician to identify which persons, among postmenopausal women and men older than 50 years, are at high risk for low trauma or fragility fractures and might require an intervention. The most recognized osteoporotic fragility fracture is the vertebral compression fracture which can lead to kyphosis or hunched backs typically seen in the elderly. DXA measurement of BMD however is recognized to be insufficient as a sole index for assessing fracture risk. DXA's limitation may be related to its inability to monitor changes in structural parameters, such as trabecular vs. cortical bone volumes, bone geometry or trabecular microarchitecture. Hence, in order to understand risks to human health and performance due to space exposure, NASA needs to expand its measurements of bone to include other contributors to skeletal integrity. To this aim, the Bone and Mineral Lab conducted a pilot study for a novel measurement of bone microarchitecture that can be obtained by retrospective analysis of DXA scans. Trabecular Bone Score (TBS) assesses changes to trabecular microarchitecture by measuring the grey color "texture" information extracted from DXA images of the lumbar spine. An analysis of TBS in 51 ISS astronauts was conducted to assess if TBS could detect 1) an effect of spaceflight and 2) a response to countermeasures independent of DXA BMD. In addition, changes in trunk body lean tissue mass and in trunk body fat tissue mass were also evaluated to explore an association between body composition, as impacted by ARED exercise, and bone microarchitecture. The pilot analysis of 51 astronaut scans of the lumbar spine suggests that, following an ISS

  11. Regional effects of ovariectomy and cadmium on bone mineral in ribs from aged female beagles

    International Nuclear Information System (INIS)

    Hurst, D.R.

    1991-01-01

    The purpose of this study was to evaluate effects of estrogen depletion and cadmium (Cd) on bone calcium and to determine if these effects were localized in specific regions of ribs. Fourteen female beagles with 45 Ca labeled skeletons were divided into four groups: sham controls (SO-); ovariectomized (OV-); shams exposed to Cd (SO+); ovariecomized exposed to Cd (OV+). Total Cd exposure period was 7 months, including 1 month by capsules and 6 months by drinking H 2 O. Ribs were taken at necropsy from 12 of the 14 dogs, and each rib was quartered. Wet, dry, and ash weights, as well as total Ca and 45 Ca content, were determined for each quarter. Analysis of ribs from control animals demonstrated that a given rib is heterogeneous in composition. One end appears to be less mineralized and more metabolically active than other regions. The OV- and OV+ mid-rib regions had significantly lower dry and ash weights than SO-. Total Ca contents of these same regions were also decreased in the OV- and OV+. The only significant change in Ca/dry and Ca/ash was observed when comparing OV+ to SO-. Analysis of treatment suggests that there are regional effects following ovariectomy increased the loss of bone mineral occurring as a result of ovariectomy. 30 refs., 1 fig

  12. Dynamic and heterogeneous effects of sibling death on children's outcomes.

    Science.gov (United States)

    Fletcher, Jason; Vidal-Fernandez, Marian; Wolfe, Barbara

    2018-01-02

    This paper explores the effects of experiencing the death of a sibling on children's developmental outcomes. Recent work has shown that experiencing a sibling death is common and long-term effects are large. We extend understanding of these effects by estimating dynamic effects on surviving siblings' cognitive and socioemotional outcomes, as well as emotional and cognitive support by parents. Using the Children of the National Longitudinal Survey of Youth 1979 (CNLSY79), we find large initial effects on cognitive and noncognitive outcomes that decline over time. We also provide evidence that the effects are larger if the surviving child is older and less prominent if the deceased child was either disabled or an infant, suggesting sensitive periods of exposure. Auxiliary results show that parental investments in the emotional support of surviving children decline following the death of their child.

  13. Evaluating heterogeneous conservation effects of forest protection in Indonesia.

    Directory of Open Access Journals (Sweden)

    Payal Shah

    Full Text Available Establishing legal protection for forest areas is the most common policy used to limit forest loss. This article evaluates the effectiveness of seven Indonesian forest protected areas introduced between 1999 and 2012. Specifically, we explore how the effectiveness of these parks varies over space. Protected areas have mixed success in preserving forest, and it is important for conservationists to understand where they work and where they do not. Observed differences in the estimated treatment effect of protection may be driven by several factors. Indonesia is particularly diverse, with the landscape, forest and forest threats varying greatly from region to region, and this diversity may drive differences in the effectiveness of protected areas in conserving forest. However, the observed variation may also be spurious and arise from differing degrees of bias in the estimated treatment effect over space. In this paper, we use a difference-in-differences approach comparing treated observations and matched controls to estimate the effect of each protected area. We then distinguish the true variation in protected area effectiveness from spurious variation driven by several sources of estimation bias. Based on our most flexible method that allows the data generating process to vary across space, we find that the national average effect of protection preserves an additional 1.1% of forest cover; however the effect of individual parks range from a decrease of 3.4% to an increase of 5.3% and the effect of most parks differ from the national average. Potential biases may affect estimates in two parks, but results consistently show Sebangau National Park is more effective while two parks are substantially less able to protect forest cover than the national average.

  14. The effect of heterogeneous defectors on the evolution of public cooperation

    Science.gov (United States)

    Chen, Tong; Hu, Xuezhi; Wang, Yongjie; Wang, Le

    2018-06-01

    In recent years,more and more private capital join the construction of cultural facilities and the organization of cultural activities in China. Actually, the organization of cultural activities by crowd-funding mechanism is a kind of multi-player game. Not all players who donate different amount of money are real cooperators. In fact, some cunning defectors may donate a little money to avoid the gossip and punishment. This part of people are very tricky. They could be seen as heterogeneous defectors. The role of heterogeneous defectors is investigated in cooperative behaviors of complex social network. Numerical results show that heterogeneous defectors could be a buffer for maintaining the public pool when synergy factor is low in public goods game (PGG). It is relatively easy to be cooperators for heterogeneous defectors when synergy factor is high in PGG. To better improve cooperation, punishment towards heterogeneous defectors and complete defectors is introduced. We are glad to find that when the defectors' loss is equal to or larger than the altruistic cooperators' punishment cost, the mechanism could make great effect. In addition, the role of heterogeneous defectors depends on the relationship between the punishment cost and the defectors' loss.

  15. Effects of growth hormone administration for 6 months on bone turnover and bone marrow fat in obese premenopausal women.

    Science.gov (United States)

    Bredella, Miriam A; Gerweck, Anu V; Barber, Lauren A; Breggia, Anne; Rosen, Clifford J; Torriani, Martin; Miller, Karen K

    2014-05-01

    Abdominal adiposity is associated with low BMD and decreased growth hormone (GH) secretion, an important regulator of bone homeostasis. The purpose of our study was to determine the effects of a short course of GH on markers of bone turnover and bone marrow fat in premenopausal women with abdominal adiposity. In a 6-month, randomized, double-blind, placebo-controlled trial we studied 79 abdominally obese premenopausal women (21-45 y) who underwent daily sc injections of GH vs. placebo. Main outcome measures were body composition by DXA and CT, bone marrow fat by proton MR spectroscopy, P1NP, CTX, 25(OH)D, hsCRP, undercarboxylated osteocalcin (ucOC), preadipocyte factor 1 (Pref 1), apolipoprotein B (ApoB), and IGF-1. GH increased IGF-1, P1NP, 25(OH)D, ucOC, bone marrow fat and lean mass, and decreased abdominal fat, hsCRP, and ApoB compared with placebo (pbone formation. A six-month decrease in abdominal fat, hsCRP, and ApoB inversely predicted 6-month change in P1NP, and 6-month increase in lean mass and 25(OH)D positively predicted 6-month change in P1NP (p≤0.05), suggesting that subjects with greatest decreases in abdominal fat, inflammation and ApoB, and the greatest increases in lean mass and 25(OH)D experienced the greatest increases in bone formation. A six-month increase in bone marrow fat correlated with 6-month increase in P1NP (trend), suggesting that subjects with the greatest increases in bone formation experienced the greatest increases in bone marrow fat. Forward stepwise regression analysis indicated that increase in lean mass and decrease in abdominal fat were positive predictors of P1NP. When IGF-1 was added to the model, it became the only predictor of P1NP. GH replacement in abdominally obese premenopausal women for 6 months increased bone turnover and bone marrow fat. Reductions in abdominal fat, and inflammation, and increases in IGF-1, lean mass and vitamin D were associated with increased bone formation. The increase in bone marrow fat may

  16. Effects of a phosphocitrate analogue on osteophyte, subchondral bone advance, and bone marrow lesions in Hartley guinea pigs.

    Science.gov (United States)

    Sun, Y; Kiraly, A J; Sun, A R; Cox, M; Mauerhan, D R; Hanley, E N

    2018-02-01

    The objectives of this study were: 1) to examine osteophyte formation, subchondral bone advance, and bone marrow lesions (BMLs) in osteoarthritis (OA)-prone Hartley guinea pigs; and 2) to assess the disease-modifying activity of an orally administered phosphocitrate 'analogue', Carolinas Molecule-01 (CM-01). Young Hartley guinea pigs were divided into two groups. The first group (n = 12) had drinking water and the second group (n = 9) had drinking water containing CM-01. Three guinea pigs in each group were euthanized at age six, 12, and 18 months, respectively. Three guinea pigs in the first group were euthanized aged three months as baseline control. Radiological, histological, and immunochemical examinations were performed to assess cartilage degeneration, osteophyte formation, subchondral bone advance, BMLs, and the levels of matrix metalloproteinse-13 (MMP13) protein expression in the knee joints of hind limbs. In addition to cartilage degeneration, osteophytes, subchondral bone advance, and BMLs increased with age. Subchondral bone advance was observed as early as six months, whereas BMLs and osteophytes were both observed mainly at 12 and 18 months. Fibrotic BMLs were found mostly underneath the degenerated cartilage on the medial side. In contrast, necrotic BMLs were found almost exclusively in the interspinous region. Orally administered CM-01 decreased all of these pathological changes and reduced the levels of MMP13 expression. Subchondral bone may play a role in cartilage degeneration. Subchondral bone changes are early events; formation of osteophytes and BMLs are later events in the OA disease process. Carolinas Molecule-01 is a promising small molecule candidate to be tested as an oral disease-modifying drug for human OA therapy. Cite this article : Y. Sun, A. J. Kiraly, A. R. Sun, M. Cox, D. R. Mauerhan, E. N. Hanley Jr. Effects of a phosphocitrate analogue on osteophyte, subchondral bone advance, and bone marrow lesions in Hartley guinea

  17. Effect of platelet-rich plasma combined with demineralised bone matrix on bone healing in rabbit ulnar defects.

    Science.gov (United States)

    Galanis, Vasilios; Fiska, Alice; Kapetanakis, Stylianos; Kazakos, Konstantinos; Demetriou, Thespis

    2017-09-01

    This study evaluates the effect of autologous platelet-rich plasma (PRP) combined with xenogeneic demineralised bone matrix (DBM) on bone healing of critical-size ulnar defects (2-2.5 times the ulnar diameter) in New Zealand White rabbits. Critical-size defects were created unilaterally in the ulna of 36 rabbits, while keeping the contralateral limb intact. They were divided into three groups. In Group A, the defect was filled with autologous PRP and in Group B, with autologous PRP combined with DBM; in Group C, the defect remained empty. The rabbits were euthanised 12 weeks postoperatively. Radiological, biomechanical and histological assessments were carried out and statistical analysis of the results was performed. Group B had significantly higher radiological and histological scores than Groups A and C. Defects in Group B showed significant new bone formation, whereas there was minimal or no new bone formation in Groups A and C. Only specimens in Group B showed macroscopic bone union. Biomechanical evaluation of the treated and intact contralateral limbs in Group B showed significant differences. In this study, statistically significant enhancement of bone healing was found in critical-size defects treated with PRP and DBM, as shown by radiological findings, gross assessment, and biomechanical and histopathological results. Defects in the two other groups remained unbridged. Therefore, PRP was effective only when it was used in combination with a bone graft. Copyright: © Singapore Medical Association

  18. Doe productivity indices and sire effects of a heterogeneous rabbit ...

    African Journals Online (AJOL)

    IJAAAR

    reproductive data obtained include annual productivity indices for each doe and sire family at birth, ... contributed to their productivity success in ..... susceptible to heat stress at temperatures above. 300c. ... Effects of weaning litter size and sex.

  19. The heterogeneous world of congruency sequence effects: An update.

    OpenAIRE

    Wout eDuthoo; Elger eAbrahamse; Senne eBraem; Senne eBraem; C. Nico Boehler; Wim eNotebaert

    2014-01-01

    Congruency sequence effects (CSEs) refer to the observation that congruency effects in conflict tasks are typically smaller following incongruent compared to following congruent trials. This measure has long been thought to provide a unique window into top-down attentional adjustments and their underlying brain mechanisms. According to the renowned conflict monitoring theory, CSEs reflect enhanced selective attention following conflict detection. Still, alternative accounts suggested that bot...

  20. Self-transparency effects in heterogeneous nonlinear scattering media and their possible use in lasers

    International Nuclear Information System (INIS)

    Al'tshuler, G.B.; Ermolaev, V.S.; Krylov, K.I.; Manenkov, A.A.; Prokhorov, A.M.

    1986-01-01

    Transmission of intense laser beams through heterogeneous scattering media is considered. Effects of intensity limitation, self-recovery of the wave front of a transmitted beam, and bistable reflection associated with the laser-induced self-transparency (suppression of scattering) of such media are predicted because of the compensation of the linear refractive-index difference Δn/sub L/ of the heterocomponents of a medium by nonlinear change Δn/sub N//sub L/ for different mechanisms of nonlinearity. Applications of these effects in lasers for Q switching and mode locking are discussed. The observation of self-transparency effects in several heterogeneous media (glass particles in toluene and nitrobenzene, and lead molybdenite powder) for cw Ar- and pulsed Nd- and CO 2 -laser radiation is reported. Q switching and mode locking have also been demonstrated with a YAG:Nd laser using nonlinear scattering in a heterogeneous cell as a control element in a laser resonator

  1. The effects of habitat connectivity and regional heterogeneity on artificial pond metacommunities.

    Science.gov (United States)

    Pedruski, Michael T; Arnott, Shelley E

    2011-05-01

    Habitat connectivity and regional heterogeneity represent two factors likely to affect biodiversity across different spatial scales. We performed a 3 × 2 factorial design experiment to investigate the effects of connectivity, heterogeneity, and their interaction on artificial pond communities of freshwater invertebrates at the local (α), among-community (β), and regional (γ) scales. Despite expectations that the effects of connectivity would depend on levels of regional heterogeneity, no significant interactions were found for any diversity index investigated at any spatial scale. While observed responses of biodiversity to connectivity and heterogeneity depended to some extent on the diversity index and spatial partitioning formula used, the general pattern shows that these factors largely act at the β scale, as opposed to the α or γ scales. We conclude that the major role of connectivity in aquatic invertebrate communities is to act as a homogenizing force with relatively little effect on diversity at the α or γ levels. Conversely, heterogeneity acts as a force maintaining differences between communities.

  2. Diverse Friendship Networks and Heterogeneous Peer Effects on Adolescent Misbehaviors

    Science.gov (United States)

    Xu, Yilan; Fan, Linlin

    2018-01-01

    This study estimates peer effects in diverse friendship networks by friend types. Evidence from friendship networks for 57,351 U.S. high school adolescents demonstrates that adolescents are more likely to make friends with someone of the same immigrant status or ethnicity ('similar friends') than those with different backgrounds ('dissimilar…

  3. Using Dirichlet Processes for Modeling Heterogeneous Treatment Effects across Sites

    Science.gov (United States)

    Miratrix, Luke; Feller, Avi; Pillai, Natesh; Pati, Debdeep

    2016-01-01

    Modeling the distribution of site level effects is an important problem, but it is also an incredibly difficult one. Current methods rely on distributional assumptions in multilevel models for estimation. There it is hoped that the partial pooling of site level estimates with overall estimates, designed to take into account individual variation as…

  4. Persistence Heterogeneity Testing in Panels with Interactive Fixed Effects

    DEFF Research Database (Denmark)

    Ergemen, Yunus Emre; Velasco, Carlos

    We consider large N,T panel data models with fixed effects, a common factor allowing for cross-section dependence, and persistent data and shocks, which are assumed fractionally integrated. In a basic setup, the main interest is on the fractional parameter of the idiosyncratic component, which...

  5. Effect of material property heterogeneity on biomechanical modeling of prostate under deformation

    International Nuclear Information System (INIS)

    Samavati, Navid; McGrath, Deirdre M; Ménard, Cynthia; Jewett, Michael A S; Van der Kwast, Theo; Brock, Kristy K

    2015-01-01

    Biomechanical model based deformable image registration has been widely used to account for prostate deformation in various medical imaging procedures. Biomechanical material properties are important components of a biomechanical model. In this study, the effect of incorporating tumor-specific material properties in the prostate biomechanical model was investigated to provide insight into the potential impact of material heterogeneity on the prostate deformation calculations. First, a simple spherical prostate and tumor model was used to analytically describe the deformations and demonstrate the fundamental effect of changes in the tumor volume and stiffness in the modeled deformation. Next, using a clinical prostate model, a parametric approach was used to describe the variations in the heterogeneous prostate model by changing tumor volume, stiffness, and location, to show the differences in the modeled deformation between heterogeneous and homogeneous prostate models. Finally, five clinical prostatectomy examples were used in separately performed homogeneous and heterogeneous biomechanical model based registrations to describe the deformations between 3D reconstructed histopathology images and ex vivo magnetic resonance imaging, and examine the potential clinical impact of modeling biomechanical heterogeneity of the prostate. The analytical formulation showed that increasing the tumor volume and stiffness could significantly increase the impact of the heterogeneous prostate model in the calculated displacement differences compared to the homogeneous model. The parametric approach using a single prostate model indicated up to 4.8 mm of displacement difference at the tumor boundary compared to a homogeneous model. Such differences in the deformation of the prostate could be potentially clinically significant given the voxel size of the ex vivo MR images (0.3  ×  0.3  ×  0.3 mm). However, no significant changes in the registration accuracy were

  6. Scaling Effects of Cr(VI) Reduction Kinetics. The Role of Geochemical Heterogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Li [Pennsylvania State Univ., State College, PA (United States); Li, Li [Pennsylvania State Univ., State College, PA (United States)

    2015-10-22

    The natural subsurface is highly heterogeneous with minerals distributed in different spatial patterns. Fundamental understanding of how mineral spatial distribution patterns regulate sorption process is important for predicting the transport and fate of chemicals. Existing studies about the sorption was carried out in well-mixed batch reactors or uniformly packed columns, with few data available on the effects of spatial heterogeneities. As a result, there is a lack of data and understanding on how spatial heterogeneities control sorption processes. In this project, we aim to understand and develop modeling capabilities to predict the sorption of Cr(VI), an omnipresent contaminant in natural systems due to its natural occurrence and industrial utilization. We systematically examine the role of spatial patterns of illite, a common clay, in determining the extent of transport limitation and scaling effects associated with Cr(VI) sorption capacity and kinetics using column experiments and reactive transport modeling. Our results showed that the sorbed mass and rates can differ by an order of magnitude due to of the illite spatial heterogeneities and transport limitation. With constraints from data, we also developed the capabilities of modeling Cr(VI) in heterogeneous media. The developed model is then utilized to understand the general principles that govern the relationship between sorption and connectivity, a key measure of the spatial pattern characteristics. This correlation can be used to estimate Cr(VI) sorption characteristics in heterogeneous porous media. Insights gained here bridge gaps between laboratory and field application in hydrogeology and geochemical field, and advance predictive understanding of reactive transport processes in the natural heterogeneous subsurface. We believe that these findings will be of interest to a large number of environmental geochemists and engineers, hydrogeologists, and those interested in contaminant fate and transport

  7. Pharmacological activation of aldehyde dehydrogenase 2 promotes osteoblast differentiation via bone morphogenetic protein-2 and induces bone anabolic effect

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Monika; Pal, Subhashis; China, Shyamsundar Pal; Porwal, Konica [Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226031 (India); Dev, Kapil [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Shrivastava, Richa [Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Raju, Kanumuri Siva Rama; Rashid, Mamunur [Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Trivedi, Arun Kumar; Sanyal, Sabyasachi [Biochemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Wahajuddin, Muhammad [Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Bhaduria, Smrati [Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Maurya, Rakesh [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Chattopadhyay, Naibedya, E-mail: n_chattopadhyay@cdri.res.in [Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226031 (India)

    2017-02-01

    Aldehyde dehydrogenases (ALDHs) are a family of enzymes involved in detoxifying aldehydes. Previously, we reported that an ALDH inhibitor, disulfiram caused bone loss in rats and among ALDHs, osteoblast expressed only ALDH2. Loss-of-function mutation in ALDH2 gene is reported to cause bone loss in humans which suggested its importance in skeletal homeostasis. We thus studied whether activating ALDH2 by N-(1, 3-benzodioxol-5-ylmethyl)-2, 6-dichlorobenzamide (alda-1) had osteogenic effect. We found that alda-1 increased and acetaldehyde decreased the differentiation of rat primary osteoblasts and expressions of ALDH2 and bone morphogenetic protein-2 (BMP-2). Silencing ALDH2 in osteoblasts abolished the alda-1 effects. Further, alda-1 attenuated the acetaldehyde-induced lipid-peroxidation and oxidative stress. BMP-2 is essential for bone regeneration and alda-1 increased its expression in osteoblasts. We then showed that alda-1 (40 mg/kg dose) augmented bone regeneration at the fracture site with concomitant increase in BMP-2 protein compared with control. The osteogenic dose (40 mg/kg) of alda-1 attained a bone marrow concentration that was stimulatory for osteoblast differentiation, suggesting that the tissue concentration of alda-1 matched its pharmacologic effect. In addition, alda-1 promoted modeling-directed bone growth and peak bone mass achievement, and increased bone mass in adult rats which reiterated its osteogenic effect. In osteopenic ovariectomized (OVX) rats, alda-1 reversed trabecular osteopenia with attendant increase in serum osteogenic marker (procollagen type I N-terminal peptide) and decrease in oxidative stress. Alda-1 has no effect on liver and kidney function. We conclude that activating ALDH2 by alda-1 had an osteoanabolic effect involving increased osteoblastic BMP-2 production and decreased OVX-induced oxidative stress. - Highlights: • Alda-1 induced osteoblast differentiation that involved upregulation of ALDH2 and BMP-2 • Alda-1

  8. Limited Benefits of Heterogeneous Dual-Task Training on Transfer Effects in Older Adults.

    Science.gov (United States)

    Lussier, Maxime; Brouillard, Philippe; Bherer, Louis

    2017-09-01

    It has often been reported that cognitive training has limited transfer effects. The present study addresses training context variability as a factor that could increase transfer effects, as well as the manifestation through time of transfer effects. Fifty-eight older adults were assigned to an active placebo or two dual-task training conditions, one in which the training context varies between sessions (heterogeneous training) and the other in a fixed training context (homogeneous training). Transfer was assessed with near and far-modality transfer tasks. Results show that heterogeneous and homogeneous training led to larger near-modality transfer effects than an active placebo (computer lessons). Transfer effects were roughly comparable in both training groups, but heterogeneous training led to a steeper improvement of the dual-task coordination learning curve within training sessions. Also, results indicated that dual-task cost did not improve in the active placebo group from the pre- to the post-training sessions. Heterogeneous training showed modest advantages over homogeneous training. Results also suggest that transfer effects on dual-task cost induced by training take place early on in the post-training session. These findings provide valuable insights on benefits arising from variability in the training protocol for maximizing transfer effects. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Effects of casein, whey and soy proteins on volumetric bone density and bone strength in immunocompromised piglets

    DEFF Research Database (Denmark)

    Budek, Alicja Zofia; Bjørnvad, Charlotte; Mølgaard, Christian

    2007-01-01

    Summary:Background and aims: Bone-promoting effect of different proteins in early life, under immunocompromised conditions, is unknown. We investigated effects of milk- and plantderived proteins on bone development in immunocompromised piglets. Methods: Newborn, colostrum-deprived piglets were...... assigned to a formula based on either casein (n=11), whey (n=11) or soy (n=10) as the protein source (each 55 g/L), and equal amounts of fat, carbohydrates, calcium and phosphorus. Results & Conclusion: Despite efforts to sustain immuno-protection (sow serum and antibiotic injections), some piglets became...... sick and were early euthanised. After 6 days, bone density (peripheral quantitative computed tomography), bone mechanical strength (three-point bending test) and serum insulin-like growth factor-I (sIGF-I) (immunoassay) were measured in the surviving piglets (casein n=5, whey n=9, soy n=5)....

  10. Osteoporosis imaging: effects of bone preservation on MDCT-based trabecular bone microstructure parameters and finite element models

    International Nuclear Information System (INIS)

    Baum, Thomas; Grande Garcia, Eduardo; Burgkart, Rainer; Gordijenko, Olga; Liebl, Hans; Jungmann, Pia M.; Gruber, Michael; Zahel, Tina; Rummeny, Ernst J.; Waldt, Simone; Bauer, Jan S.

    2015-01-01

    Osteoporosis is defined as a skeletal disorder characterized by compromised bone strength due to a reduction of bone mass and deterioration of bone microstructure predisposing an individual to an increased risk of fracture. Trabecular bone microstructure analysis and finite element models (FEM) have shown to improve the prediction of bone strength beyond bone mineral density (BMD) measurements. These computational methods have been developed and validated in specimens preserved in formalin solution or by freezing. However, little is known about the effects of preservation on trabecular bone microstructure and FEM. The purpose of this observational study was to investigate the effects of preservation on trabecular bone microstructure and FEM in human vertebrae. Four thoracic vertebrae were harvested from each of three fresh human cadavers (n = 12). Multi-detector computed tomography (MDCT) images were obtained at baseline, 3 and 6 month follow-up. In the intervals between MDCT imaging, two vertebrae from each donor were formalin-fixed and frozen, respectively. BMD, trabecular bone microstructure parameters (histomorphometry and fractal dimension), and FEM-based apparent compressive modulus (ACM) were determined in the MDCT images and validated by mechanical testing to failure of the vertebrae after 6 months. Changes of BMD, trabecular bone microstructure parameters, and FEM-based ACM in formalin-fixed and frozen vertebrae over 6 months ranged between 1.0–5.6 % and 1.3–6.1 %, respectively, and were not statistically significant (p > 0.05). BMD, trabecular bone microstructure parameters, and FEM-based ACM as assessed at baseline, 3 and 6 month follow-up correlated significantly with mechanically determined failure load (r = 0.89–0.99; p < 0.05). The correlation coefficients r were not significantly different for the two preservation methods (p > 0.05). Formalin fixation and freezing up to six months showed no significant effects on trabecular bone microstructure

  11. Experimental study on the radiation effects to the bone growth

    International Nuclear Information System (INIS)

    Sakai, Yasuhiko

    1980-01-01

    The radiation effects on growing bone were studied using immature rabbits. The irradiation was done with telecobalt to the right knee joint. The rabbits were divided into six groups according to the dose, such as 1,000, 2,000, 3,000, 4,000, 6,000 and 8,000 rad respectively. The effects of irradiation were investigated by RI-scintigraphy, X-ray photography and pathohistological examination. The following results were obtained. 1. In RI-scintigraphy using sup(99m)Tc-MDP, the change of accumulation ratio of the irradiated side was investigated. In terms of chronological observation, the accumulation ratio decreased most 5 weeks after irradiation and subsequently increased in the group irradiated with less than 4,000 rad. In the 6,000 rad group, the accumulation ratio decreased rapidly until 5 weeks after irradiation, and subsequently increased slightly. In the 8,000 rad group, the accumulation ratio progressively decreased unabated during the time observed. 2. X-ray findings of irradiated bones were as follows: In the group irradiated with more than 3,000 rad, sclerosis of the metaphysis and unclearness of the trabecula, thickening of the compact bone, bending, fissure and fracture of the bone appeared early with increased frequency with an increased in radiation doses. Also, according to an increase in radiation doses, growth inhibition in the length of the tibia was conspicuous. 3. In the histopathological findings, disturbances of the epiphyseal cartilage, the blood vessel system, trabecula, and medullary tissue becomes intense with increasing radiation doses. (author)

  12. Immunochemical heterogeneity of calcitonin in man: effect on radioimmunoassay

    International Nuclear Information System (INIS)

    Snider, R.H.; Moore, C.F.

    1977-01-01

    Determinations of blood levels of human calcitonin by radioimmunoassay have varied considerably in different laboratories. Much of the controversy over calcitonin levels can be attributed to the multiplicity of immunoreactive forms of the hormone (iCT), the differing region specificities of the antisera utilized for measurement by radioimmunoassay, protein effects, different rates of degradation of the various iCT fractions and the specific methodology of the radioimmunoassay

  13. Effective Data Acquisition Protocol for Multi-Hop Heterogeneous Wireless Sensor Networks Using Compressive Sensing

    Directory of Open Access Journals (Sweden)

    Ahmed M. Khedr

    2015-10-01

    Full Text Available In designing wireless sensor networks (WSNs, it is important to reduce energy dissipation and prolong network lifetime. Clustering of nodes is one of the most effective approaches for conserving energy in WSNs. Cluster formation protocols generally consider the heterogeneity of sensor nodes in terms of energy difference of nodes but ignore the different transmission ranges of them. In this paper, we propose an effective data acquisition clustered protocol using compressive sensing (EDACP-CS for heterogeneous WSNs that aims to conserve the energy of sensor nodes in the presence of energy and transmission range heterogeneity. In EDACP-CS, cluster heads are selected based on the distance from the base station and sensor residual energy. Simulation results show that our protocol offers a much better performance than the existing protocols in terms of energy consumption, stability, network lifetime, and throughput.

  14. The effect of material heterogeneity in curved composite beams for use in aircraft structures

    Science.gov (United States)

    Otoole, Brendan J.; Santare, Michael H.

    1992-01-01

    A design tool is presented for predicting the effect of material heterogeneity on the performance of curved composite beams for use in aircraft fuselage structures. Material heterogeneity can be induced during processes such as sheet forming and stretch forming of thermoplastic composites. This heterogeneity can be introduced in the form of fiber realignment and spreading during the manufacturing process causing a gradient in material properties in both the radial and tangential directions. The analysis procedure uses a separate two-dimensional elasticity solution for the stresses in the flanges and web sections of the beam. The separate solutions are coupled by requiring the forces and displacements match at the section boundaries. Analysis is performed for curved beams loaded in pure bending and uniform pressure. The beams can be of any general cross-section such as a hat, T-, I-, or J-beam. Preliminary results show that geometry of the beam dictates the effect of heterogeneity on performance. Heterogeneity plays a much larger role in beams with a small average radius to depth ratio, R/t, where R is the average radius of the beam and t is the difference between the inside and outside radius. Results of the analysis are in the form of stresses and displacements, and they are compared to both mechanics of materials and numerical solutions obtained using finite element analysis.

  15. The heterogeneous world of congruency sequence effects: An update.

    Directory of Open Access Journals (Sweden)

    Wout eDuthoo

    2014-09-01

    Full Text Available Congruency sequence effects (CSEs refer to the observation that congruency effects in conflict tasks are typically smaller following incongruent compared to following congruent trials. This measure has long been thought to provide a unique window into top-down attentional adjustments and their underlying brain mechanisms. According to the renowned conflict monitoring theory, CSEs reflect enhanced selective attention following conflict detection. Still, alternative accounts suggested that bottom-up associative learning suffices to explain the pattern of reaction times and error rates. A couple of years ago, a review by Egner (2007 pitted these two rivalry accounts against each other, concluding that both conflict adaptation and feature integration contribute to the CSE. Since then, a wealth of studies has further debated this issue, and two additional accounts have been proposed, offering intriguing alternative explanations. Contingency learning accounts put forward that predictive relationships between stimuli and responses drive the CSE, whereas the repetition expectancy hypothesis suggests that top-down, expectancy-driven control adjustments affect the CSE. In the present paper, we build further on the previous review (Egner, 2007 by summarizing and integrating recent behavioural and neurophysiological studies on the CSE. In doing so, we evaluate the relative contribution and theoretical value of the different attentional and memory-based accounts. Moreover, we review how all of these influences can be experimentally isolated, and discuss designs and procedures that can critically judge between them.

  16. The heterogeneous world of congruency sequence effects: an update.

    Science.gov (United States)

    Duthoo, Wout; Abrahamse, Elger L; Braem, Senne; Boehler, Carsten N; Notebaert, Wim

    2014-01-01

    Congruency sequence effects (CSEs) refer to the observation that congruency effects in conflict tasks are typically smaller following incongruent compared to following congruent trials. This measure has long been thought to provide a unique window into top-down attentional adjustments and their underlying brain mechanisms. According to the renowned conflict monitoring theory, CSEs reflect enhanced selective attention following conflict detection. Still, alternative accounts suggested that bottom-up associative learning suffices to explain the pattern of reaction times and error rates. A couple of years ago, a review by Egner (2007) pitted these two rivalry accounts against each other, concluding that both conflict adaptation and feature integration contribute to the CSE. Since then, a wealth of studies has further debated this issue, and two additional accounts have been proposed, offering intriguing alternative explanations. Contingency learning accounts put forward that predictive relationships between stimuli and responses drive the CSE, whereas the repetition expectancy hypothesis suggests that top-down, expectancy-driven control adjustments affect the CSE. In the present paper, we build further on the previous review (Egner, 2007) by summarizing and integrating recent behavioral and neurophysiological studies on the CSE. In doing so, we evaluate the relative contribution and theoretical value of the different attentional and memory-based accounts. Moreover, we review how all of these influences can be experimentally isolated, and discuss designs and procedures that can critically judge between them.

  17. Effects of Fiber Type and Size on the Heterogeneity of Oxygen Distribution in Exercising Skeletal Muscle

    Science.gov (United States)

    Liu, Gang; Mac Gabhann, Feilim; Popel, Aleksander S.

    2012-01-01

    The process of oxygen delivery from capillary to muscle fiber is essential for a tissue with variable oxygen demand, such as skeletal muscle. Oxygen distribution in exercising skeletal muscle is regulated by convective oxygen transport in the blood vessels, oxygen diffusion and consumption in the tissue. Spatial heterogeneities in oxygen supply, such as microvascular architecture and hemodynamic variables, had been observed experimentally and their marked effects on oxygen exchange had been confirmed using mathematical models. In this study, we investigate the effects of heterogeneities in oxygen demand on tissue oxygenation distribution using a multiscale oxygen transport model. Muscles are composed of different ratios of the various fiber types. Each fiber type has characteristic values of several parameters, including fiber size, oxygen consumption, myoglobin concentration, and oxygen diffusivity. Using experimentally measured parameters for different fiber types and applying them to the rat extensor digitorum longus muscle, we evaluated the effects of heterogeneous fiber size and fiber type properties on the oxygen distribution profile. Our simulation results suggest a marked increase in spatial heterogeneity of oxygen due to fiber size distribution in a mixed muscle. Our simulations also suggest that the combined effects of fiber type properties, except size, do not contribute significantly to the tissue oxygen spatial heterogeneity. However, the incorporation of the difference in oxygen consumption rates of different fiber types alone causes higher oxygen heterogeneity compared to control cases with uniform fiber properties. In contrast, incorporating variation in other fiber type-specific properties, such as myoglobin concentration, causes little change in spatial tissue oxygenation profiles. PMID:23028531

  18. Synergistic effect of parathyroid hormone and growth hormone on trabecular and cortical bone formation in hypophysectomized rats.

    Science.gov (United States)

    Guevarra, Maria Sarah N; Yeh, James K; Castro Magana, Mariano; Aloia, John F

    2010-01-01

    Growth hormone (GH) deficiency in pediatric patients results in short stature and osteopenia. We postulated that the GH and parathyroid hormone (PTH) combination would result in improvement in bone growth and bone formation. Forty hypophysectomized female rats at age 8 weeks were divided into hypophysectomy (HX), HX + PTH (62.5 microg/kg, s.c. daily), HX + GH (3.33 mg/kg, s.c. daily), and HX + PTH + GH for a 4-week study. GH increased body weight, bone growth, bone mineral content (BMC) and bone mineral density (BMD), whereas PTH increased BMC and BMD without a significant effect on bone size. GH increased both periosteal and endocortical bone formation and cortical size, while PTH increased only endocortical bone formation. GH mitigated the trabecular bone loss by increasing bone formation, while PTH increased bone mass by increasing bone formation and suppressing osteoclast number per bone area. The result of combined intervention shows an increase in trabecular, periosteal and endocortical bone formation and suppression of bone resorption resulting in a synergistic effect on increasing trabecular and cortical bone volume and BMD. The combination treatment of PTH and GH increases bone growth, bone formation, decreases bone resorption and has a synergistic effect on increasing bone density and bone mass. Copyright (c) 2010 S. Karger AG, Basel.

  19. Effects of Antiseptic Solutions Commonly Used in Dentistry on Bone Viability, Bone Morphology, and Release of Growth Factors.

    Science.gov (United States)

    Sawada, Kosaku; Fujioka-Kobayashi, Masako; Kobayashi, Eizaburo; Schaller, Benoit; Miron, Richard J

    2016-02-01

    Antiseptic solutions are commonly used in dentistry for a number of sterilization procedures, including harvesting of bone chips, irrigation of extraction sockets, and sterilization of osteonecrotic bone. Despite its widespread use, little information is available regarding the effects of various antiseptic solutions on bone cell viability, morphology, and the release of growth factors. The antiseptic solutions included 1) 0.5% povidone iodine (PI), 2) 0.2% chlorhexidine diguluconate (CHX), 3) 1% hydrogen peroxide (H2O2), and 4) 0.25% sodium hypochlorite (HYP). Bone samples collected from porcine mandibular cortical bone were rinsed in the antiseptic solutions for 10 minutes and assessed for cell viability using an MTS assay and protein release of transforming growth factor (TGF-β1), bone morphogenetic protein 2 (BMP2), vascular endothelial growth factor (VEGF), interleukin (IL)-1β, and receptor activator of nuclear factor κB ligand (RANKL) using an enzyme-linked immunosorbent assay at 15 minutes and 4 hours after rinsing. After antiseptic rinsing, changes to the surface protein content showed marked alterations, with an abundant protein layer remaining on CHX-rinsed bone samples. The amount of surface protein content gradually decreased in the following order: CHX, H2O2, PI, and HYP. A similar trend was also observed for the relative cell viability from within bone samples after rinsing, with up to 6 times more viable cells found in the CHX-rinsed bone samples than in the HYP- and PI-rinsed samples. An analysis of the growth factors found that both HYP and PI had significantly lower VEGF and TGF-β1 protein release from bone samples at 15 minutes and 4 hours after rinsing compared with CHX and H2O2. A similar trend was observed for RANKL and IL-1β protein release, although no change was observed for BMP2. The results from the present study have demonstrated that antiseptic solutions present with very different effects on bone samples after 10 minutes of

  20. Effect of vitamin K2 and growth hormone on the long bones in hypophysectomized young rats: a bone histomorphometry study.

    Science.gov (United States)

    Iwamoto, Jun; Takeda, Tsuyoshi; Sato, Yoshihiro; Yeh, James K

    2007-01-01

    The purpose of the present study was to determine whether vitamin K(2) and growth hormone (GH) had an additive effect on the long bones in hypophysectomized young rats. Forty-eight female Sprague-Dawley rats (6 weeks old) were assigned to the following five groups by the stratified weight randomization method: intact controls, hypophysectomy (HX) alone, HX + vitamin K(2) (30 mg/kg, p.o., daily), HX + GH (0.625 mg/kg, s.c., 5 days a week), and HX + vitamin K(2) + GH. The duration of the experiment was 4 weeks. HX resulted in a reduction of the cancellous bone volume/total tissue volume (BV/TV) at the proximal tibial metaphysis, as well as decreasing the total tissue area and cortical area of the tibial diaphysis. These changes resulted from a decrease of the longitudinal growth rate and the bone formation rate (BFR)/TV of cancellous bone, as well as a decrease of the periosteal BFR/bone surface (BS) and an increase of endocortical bone turnover (indicated by the BFR/BS) in cortical bone. Administration of vitamin K(2) to HX rats did not affect the cancellous BV/TV or the cortical area. On the other hand, GH completely prevented the decrease of total tissue area and cortical area in cortical bone, as well as the decrease of marrow area and endocortical circumference, by increasing the periosteal BFR/BS compared with that in intact controls and reversing the increase of endocortical bone turnover (BFR/BS). However, GH only partly improved the reduction of the cancellous BV/TV, despite an increase of the longitudinal growth rate and BFR/TV compared with those of intact controls. When administered with GH, vitamin K(2) counteracted the reduction of endocortical bone turnover (BFR/BS) and circumference caused by GH treatment, resulting in no significant difference of marrow area from that in untreated HX rats. These results suggest that, despite the lack of an obvious effect on bone parameters, vitamin K(2) normalizes the size of the marrow cavity during development of

  1. The effect of semelil (angipars® on bone resorption and bone formation markers in type 2 diabetic patients

    Directory of Open Access Journals (Sweden)

    Hasani-Ranjbar Shirin

    2012-12-01

    Full Text Available Abstract Background and purpose of the study Diabetes mellitus has been recognized as a major risk factor for osteoporosis in which bone turnover is affected by different mechanisms. As the morbidity, mortality and financial cost related to osteoporosis are expected to rise in Iran in coming years, and considering the efficacy of Angipars® for improvement of different ulcers which made it a new herbal drug in diabetic foot ulcer, there is a need to evaluate the effect of this new drug on different organs including bone resorption and bone formation markers. Methods In this randomized, double- blind clinical trial, 61 diabetic patients were included. The subjects were randomly divided into intervention and control groups. Subjects of intervention group received 100 mg of Angipars® twice a day. Laboratory tests including bone resorption and bone formation markers were performed at baseline and after 3 months. Result 31 patients in study group and 30 patients in control group finished the study. The mean age of the study population and the mean disease duration was respectively 51.8 ± 6.2 and 7.5 ± 4.7 years with no significant differences between intervention and control patients. No statistically significant differences between patients and controls were observed in pyridinoline, osteocalcin, urine calcium, bone alkaline phosphatase and tumor necrosis factor (TNF-α. Only urine creatinine level significantly changed between two groups after 3 month of treatment (p-value: 0.029 Conclusion In conclusion, the findings of this study indicate that Semelil (Angipars® had no beneficial or harmful effects on bone. It might be other effects of this new component on bone turnover process which need more studies and more time to be discovered.

  2. Effects of orthopedic implants with a polycaprolactone polymer coating containing bone morphogenetic protein-2 on osseointegration in bones of sheep.

    Science.gov (United States)

    Niehaus, Andrew J; Anderson, David E; Samii, Valerie F; Weisbrode, Steven E; Johnson, Jed K; Noon, Mike S; Tomasko, David L; Lannutti, John J

    2009-11-01

    To determine elution characteristics of bone morphogenetic protein (BMP)-2 from a polycaprolactone coating applied to orthopedic implants and determine effects of this coating on osseointegration. 6 sheep. An in vitro study was conducted to determine BMP-2 elution from polycaprolactone-coated implants. An in vivo study was conducted to determine the effects on osseointegration when the polycaprolactone with BMP-2 coating was applied to bone screws. Osseointegration was assessed via radiography, measurement of peak removal torque and bone mineral density, and histomorphometric analysis. Physiologic response was assessed by measuring serum bone-specific alkaline phosphatase activity and uptake of bone markers. Mean +/- SD elution on day 1 of the in vitro study was 263 +/- 152 pg/d, which then maintained a plateau at 59.8 +/- 29.1 pg/d. Mean peak removal torque for screws coated with polycalprolactone and BMP-2 (0.91 +/- 0.65 dN x m) and screws coated with polycaprolactone alone (0.97 +/- 1.30 dN.m) did not differ significantly from that for the control screws (2.34 +/- 1.62 dN x m). Mean bone mineral densities were 0.535 +/- 0.060 g/cm(2), 0.596 +/- 0.093 g/cm(2), and 0.524 +/- 0.142 g/cm(2) for the polycaprolactone-BMP-2-coated, polycaprolactone-coated, and control screws, respectively, and did not differ significantly among groups. Histologically, bone was in closer apposition to the implant with the control screws than with either of the coated screws. BMP-2 within the polycaprolactone coating did not stimulate osteogenesis. The polycaprolactone coating appeared to cause a barrier effect that prevented formation of new bone. A longer period or use of another carrier polymer may result in increased osseointegration.

  3. NOx AND HETEROGENEITY EFFECTS IN HIGH LEVEL WASTE (HLW)

    International Nuclear Information System (INIS)

    Meisel, Dan; Camaioni, Donald M.; Orlando, Thom

    2000-01-01

    We summarize contributions from our EMSP supported research to several field operations of the Office of Environmental Management (EM). In particular we emphasize its impact on safety programs at the Hanford and other EM sites where storage, maintenance and handling of HLW is a major mission. In recent years we were engaged in coordinated efforts to understand the chemistry initiated by radiation in HLW. Three projects of the EMSP (''The NOx System in Nuclear Waste,'' ''Mechanisms and Kinetics of Organic Aging in High Level Nuclear Wastes, D. Camaioni--PI'' and ''Interfacial Radiolysis Effects in Tanks Waste, T. Orlando--PI'') were involved in that effort, which included a team at Argonne, later moved to the University of Notre Dame, and two teams at the Pacific Northwest National Laboratory. Much effort was invested in integrating the results of the scientific studies into the engineering operations via coordination meetings and participation in various stages of the resolution of some of the outstanding safety issues at the sites. However, in this Abstract we summarize the effort at Notre Dame

  4. Effects of bone morphogenetic protein-2 on bone cells in primary culture: immunohistochemical and electronmicroscopical studies

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, I.; Prochnow, N.; Mueller, K.M. [Berufsgenossenschaftliche Kliniken Bergmannsheil, Bochum (Germany). Inst. fuer Pathologie; Wiemann, M.; Schirrmacher, K.; Bingmann, D. [Essen Univ. (Germany). Inst. fuer Physiologie; Sebald, W. [Wuerzburg Univ. (Germany). Inst. fuer Physiologische Chemie II

    2001-02-01

    Bone morphogenetic protein 2 (BMP-2), among other morphogenetic effects on non osseous tissues, promotes bone formation in vivo. Therefore, BMP-2 may accelerate the integration of osseous implants. Although the effects of BMPs on cell proliferation have been studied extensively in vivo or in cell lines, little is published about effects on bone cells in primary cultures, especially on cell differentiation. As such information is a prerequisite to understand and to control effects of BMPs on cells at the surface of implant materials, the present experiments aimed to describe effects of BMP-2 on primary cultures derived from calvarial fragments of neonatal rats. The cells were stimulated with 50 nM BMP-2 added to the nutrient medium for 3 or 6 days. Light- and electronmicroscopical studies showed that cells in the sprouting zones were larger and more often spindle shaped. Stimulated cells had more nucleoli than control cells and the endoplasmic reticulum was widened. They retained properties of typical bone cells: An immunhistochemical analysis showed that stimulated cells increased the activity of alkaline phosphatase, they secreted collagen type I and to a minor extent collagen type III. In BMP-2 treated cells the pattern of cells stained for actin, desmin and vimentin hardly changed whereas extracellular fibronectin appeared to be less cross-linked in BMP-2 treated cultures. The distribution and labeling strength of osteocalcin, a specific marker protein of bone cells did not change markedly. After exposure to BMP-2 cells tended to detach from the cover slips. Electron microscopy showed a reduced number of cell processes possibly facilitating the detachment and/or mobility. Stimulated cells contained an increased number of lamellar bodies which may reflect an increased synthesis and/or membrane turnover. Staining of non-osseous cells with anti-CD68-or anti-myeloid antibodies revealed that the small percentage of these cells regularly occurring in primary cultures

  5. Heterogeneous substitution effects in chlorocyanomethyl radical and chlorocyanocarbene.

    Science.gov (United States)

    Khuseynov, Dmitry; Dixon, Andrew R; Goebbert, Daniel J; Sanov, Andrei

    2013-10-17

    We report a photoelectron-imaging investigation of the chlorocyanomethyl radical (CHClCN) and the corresponding carbene (CClCN). The results are discussed in comparison with the corresponding dichloro- and dicyano-substituted species, focusing on the divergent effects of the halogen and pseudohalogen (CN) substitutions. A cooperative (captodative) interaction of the π-donor Cl and π-acceptor cyano groups favors the increased stability of the CHClCN radical, but a competition of the two substituents is observed in the singlet-triplet splitting of the carbene. The vertical detachment energy (VDE) of CHClCN(-) is determined to be 2.39 ± 0.04 eV, with the broad photoelectron band consistent with the significant geometry change predicted by theory for the detachment transition. The adiabatic electron affinity of CHClCN, EA = 1.86 ± 0.08 eV, is estimated on the basis of the experimental VDE and the computed difference between the VDE and EA values. This result allows the calculation of the bond dissociation energy of chloroacetonitrile, DH298(H-CHClCN) = 87.0 ± 2.7 kcal/mol. Photoelectron imaging of CClCN(-) reveals two main transitions, assigned to the singlet ((1)A') and triplet ((3)A″) states of the CClCN carbene. The respective VDEs are 2.76 ± 0.05 and 3.25 ± 0.05 eV. The experimental results are in good agreement with the theoretically predicted singlet-triplet vertical energy gap at the anion geometry, but inconclusive with regard to the adiabatic singlet-triplet splitting in CClCN. Consistent with the experimental findings, ab initio calculations using the spin-flip approach in combination with the coupled-cluster theory, indicate that the (1)A' and (3)A″ states are nearly degenerate, with the singlet state lying adiabatically only ∼0.01 eV below the triplet.

  6. Bone density and body composition in chronic renal failure: effects of growth hormone treatment

    NARCIS (Netherlands)

    van der Sluis, I. M.; Boot, A. M.; Nauta, J.; Hop, W. C.; de Jong, M. C.; Lilien, M. R.; Groothoff, J. W.; van Wijk, A. E.; Pols, H. A.; Hokken-Koelega, A. C.; de Muinck Keizer-Schrama, S. M.

    2000-01-01

    Metabolic bone disease and growth retardation are common complications of chronic renal failure (CRF). We evaluated bone mineral density (BMD), bone metabolism, body composition and growth in children with CRF, and the effect of growth hormone treatment (GHRx) on these variables. Thirty-three

  7. Facile Hydrothermal Preparation of ZNO/CO3O4 Heterogeneous Nanostructures and its Photovoltaic Effect

    Science.gov (United States)

    Wei, Fanan; Jiang, Minlin; Liu, Lianqing

    2015-07-01

    Photovoltaic technology offers great potential in the replacement of fossil fuel resources, but still suffers from high device fabrication cost. Herein, we attempted to provide a solution to these issues with heterogeneous nanostructures. Firstly, Zinc oxide (ZnO)/cobalt oxide (Co3O4) heterojunction nanowires are prepared through facile fabrication methods. By assembling Co(OH)2 nanoplates on ZnO nanowire arrays, the ZnO/Co3O4 heterogeneous nanostructures are uniformly synthesized on ITO coated glass and wafer. Current (I)-voltage (V) measurement through conductive atomic force microscope shows excellent photovoltaic effect. And, the heterojunction nanostructures shows unprecedented high open circuit voltage. Therefore, the potential application of the heterogeneous nanostructures in solar cells is demonstrated.

  8. Oxalic acid as a heterogeneous ice nucleus in the upper troposphere and its indirect aerosol effect

    Directory of Open Access Journals (Sweden)

    B. Zobrist

    2006-01-01

    Full Text Available Heterogeneous ice freezing points of aqueous solutions containing various immersed solid dicarboxylic acids (oxalic, adipic, succinic, phthalic and fumaric have been measured with a differential scanning calorimeter. The results show that only the dihydrate of oxalic acid (OAD acts as a heterogeneous ice nucleus, with an increase in freezing temperature between 2 and 5 K depending on solution composition. In several field campaigns, oxalic acid enriched particles have been detected in the upper troposphere with single particle aerosol mass spectrometry. Simulations with a microphysical box model indicate that the presence of OAD may reduce the ice particle number density in cirrus clouds by up to ~50% when compared to exclusively homogeneous cirrus formation without OAD. Using the ECHAM4 climate model we estimate the global net radiative effect caused by this heterogeneous freezing to result in a cooling as high as −0.3 Wm−2.

  9. [Effectiveness of conventional diagnostic radiology and nuclear medicine in the treatment of pain from bone metastases].

    Science.gov (United States)

    Genovese, Eugenio Annibale; Mallardo, Vania; Vaccaro, Andrea; Santagata, Mario; Raucci, Antonio; D'Agosto, Gianfranco; Fontanarosa, Antonio; Schillirò, Francesco

    2013-01-01

    Bone is one of the most common metastasis sites from solid tumors. Bone pain due to metastatic neoplastic growth is due to tumor infiltration and expansion of bone membranes. Treatment of acute and chronic pain represents one of the greatest problems in clinical oncology, requiring a multidisciplinary approach. This review focuses on the effectiveness of conventional diagnostic radiology and nuclear medicine for the detection, management and treatment of pain from bone metastasis.

  10. Heterogeneity of Rapid Sand Filters and Its Effect on Contaminant Transport and Nitrification Performance

    DEFF Research Database (Denmark)

    Lopato, Laure Rose; Galaj, Zofia; Delpont, Sébastien

    2011-01-01

    Laboratory and full-scale experiments were conducted to investigate the development and effect of heterogeneity caused by filter media nonuniformity, biofilm, particles, precipitates, and gas bubbles in rapid sand filters used for drinking-water treatment. Salt tracer experiments were conducted...

  11. Effect of heterogeneous microvasculature distribution on drug delivery to solid tumour

    International Nuclear Information System (INIS)

    Zhan, Wenbo; Xu, Xiao Yun; Gedroyc, Wladyslaw

    2014-01-01

    Most of the computational models of drug transport in vascular tumours assume a uniform distribution of blood vessels through which anti-cancer drugs are delivered. However, it is well known that solid tumours are characterized by dilated microvasculature with non-uniform diameters and irregular branching patterns. In this study, the effect of heterogeneous vasculature on drug transport and uptake is investigated by means of mathematical modelling of the key physical and biochemical processes in drug delivery. An anatomically realistic tumour model accounting for heterogeneous distribution of blood vessels is reconstructed based on magnetic resonance images of a liver tumour. Numerical simulations are performed for different drug delivery modes, including direct continuous infusion and thermosensitive liposome-mediated delivery, and the anti-cancer effectiveness is evaluated through changes in tumour cell density based on predicted intracellular concentrations. Comparisons are made between regions of different vascular density, and between the two drug delivery modes. Our numerical results show that both extra- and intra-cellular concentrations in the liver tumour are non-uniform owing to the heterogeneous distribution of tumour vasculature. Drugs accumulate faster in well-vascularized regions, where they are also cleared out more quickly, resulting in less effective tumour cell killing in these regions. Compared with direct continuous infusion, the influence of heterogeneous vasculature on anti-cancer effectiveness is more pronounced for thermosensitive liposome-mediated delivery. (paper)

  12. Effects on bone geometry, density, and microarchitecture in the distal radius but not the tibia in women with primary hyperparathyroidism

    DEFF Research Database (Denmark)

    Hansen, Stinus; Beck Jensen, Jens-Erik; Rasmussen, Lars

    2010-01-01

    Patients with primary hyperparathyroidism (PHPT) have continuously elevated parathyroid hormone (PTH) and consequently increased bone turnover with negative effects on cortical (Ct) bone with preservation of trabecular (Tb) bone. High-resolution peripheral quantitative computed tomography (HR...

  13. The effect of carrier type on bone regeneration of demineralized bone matrix in vivo.

    Science.gov (United States)

    Tavakol, Shima; Khoshzaban, Ahad; Azami, Mahmoud; Kashani, Iraj Ragerdi; Tavakol, Hani; Yazdanifar, Mahbube; Sorkhabadi, Seyed Mahdi Rezayat

    2013-11-01

    Demineralized bone matrix (DBM) is a bone substitute biomaterial used as an excellent grafting material. Some factors such as carrier type might affect the healing potential of this material. The background data discuss the present status of the field: Albumin as a main protein in blood and carboxymethyl cellulose (CMC) were applied frequently in the DBM gels. We investigated the bone-repairing properties of 2 DBMs with different carriers. Bone regeneration in 3 groups of rat calvaria treated with DBM from the Iranian Tissue Bank Research and Preparation Center, DBM from Hans Biomed Corporation, and an empty cavity was studied. Albumin and CMC as carriers were used. The results of bone regeneration in the samples after 1, 4, and 8 weeks of implantation were compared. The block of the histologic samples was stained with hematoxylin and eosin, and the percentage area of bone formation was calculated using the histomorphometry method. The results of in vivo tests showed a significantly stronger new regenerated bone occupation in the DBM with albumin carrier compared with the one with CMC 8 weeks after the implantation. The 2 types of DBM had a significant difference in bone regeneration. This difference is attributed to the type of carriers. Albumin could improve mineralization and bioactivity compared with CMC.

  14. Collagen type I from bovine bone. Effect of animal age, bone anatomy and drying methodology on extraction yield, self-assembly, thermal behaviour and electrokinetic potential

    OpenAIRE

    Ferraro, Vincenza; Gaillard-Martinie, Brigitte; Sayd, Thierry; Chambon, Christophe; Anton, Marc; Sante-Lhoutellier, Veronique

    2017-01-01

    Natural collagen is easily available from animal tissues such as bones. Main limitations reported in the use of natural collagen are heterogeneity and loss of integrity during recovery. However, its natural complexity, functionality and bioactivity still remain to be achieved through synthetic and recombinant ways. Variability of physicochemical prope...

  15. Effect of heterogeneities on the thermoelectric power of pressure vessel steel

    International Nuclear Information System (INIS)

    Simonet, L.

    2006-12-01

    In service working conditions, the vessel of the Pressurized Water Reactors (PWR) undergoes an ageing due to irradiation. In order to follow the evolution of the mechanical characteristics of the steel in service, EDF launched a surveillance program which consists to carry out mechanical tests on samples aged in reactor. However, the results of these tests have the disadvantage to be affected by the presence of heterogeneities within the steel. Indeed, because of its manufacturing process, the steel contains segregated areas. Thus, EDF launched Thermoelectric Power Measurements (TEP) on the resilience samples of the surveillance program, to complete the mechanical tests and to help with their interpretation. However, these measurements are today difficult to analyse because they include at the same time the effect of the irradiation and the effect of the metallurgical heterogeneities. The aim of this work consisted in evaluating the effect of the heterogeneities on the TEP of the non-irradiated vessel steel. For that, a numerical model was developed which allows to calculate the TEP of a composite structure. We have shown that the model is pertinent to highlight the effect of the heterogeneities on the TEP of the vessel steel, which is considered like a 'matrix'/'segregation' composite. The model allowed us to put emphasis on the influence of different parameters on the TEP measurement. We have thus showed that the measurements conditions have an important effect on the obtained TEP value (influence of the applied pressure, the position of the sample on the device, the site of the metallurgical heterogeneities,...). (author)

  16. The effect of heterogeneous dynamics of online users on information filtering

    International Nuclear Information System (INIS)

    Chen, Bo-Lun; Zeng, An; Chen, Ling

    2015-01-01

    The rapid expansion of the Internet requires effective information filtering techniques to extract the most essential and relevant information for online users. Many recommendation algorithms have been proposed to predict the future items that a given user might be interested in. However, there is an important issue that has always been ignored so far in related works, namely the heterogeneous dynamics of online users. The interest of active users changes more often than that of less active users, which asks for different update frequency of their recommendation lists. In this paper, we develop a framework to study the effect of heterogeneous dynamics of users on the recommendation performance. We find that the personalized application of recommendation algorithms results in remarkable improvement in the recommendation accuracy and diversity. Our findings may help online retailers make better use of the existing recommendation methods. - Highlights: • We study the effect of heterogeneous dynamics of users on recommendation. • Due to the user heterogeneity, their amount of links in the probe set is different. • The personalized algorithm implementation improves the recommendation performance. • Our results suggest different update frequency for users – recommendation list.

  17. The effect of heterogeneous dynamics of online users on information filtering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bo-Lun [Department of Computer Science, Yangzhou University of China, Yangzhou 225127 (China); Department of Computer Science, Nanjing University of Aeronautics and Astronautics of China, Nanjing 210016 (China); Department of Physics, University of Fribourg, Chemin du Musee 3, CH-1700 Fribourg (Switzerland); Zeng, An, E-mail: anzeng@bnu.edu.cn [School of Systems Science, Beijing Normal University, Beijing 100875 (China); Chen, Ling [Department of Computer Science, Yangzhou University of China, Yangzhou 225127 (China); Department of Computer Science, Nanjing University of Aeronautics and Astronautics of China, Nanjing 210016 (China)

    2015-11-06

    The rapid expansion of the Internet requires effective information filtering techniques to extract the most essential and relevant information for online users. Many recommendation algorithms have been proposed to predict the future items that a given user might be interested in. However, there is an important issue that has always been ignored so far in related works, namely the heterogeneous dynamics of online users. The interest of active users changes more often than that of less active users, which asks for different update frequency of their recommendation lists. In this paper, we develop a framework to study the effect of heterogeneous dynamics of users on the recommendation performance. We find that the personalized application of recommendation algorithms results in remarkable improvement in the recommendation accuracy and diversity. Our findings may help online retailers make better use of the existing recommendation methods. - Highlights: • We study the effect of heterogeneous dynamics of users on recommendation. • Due to the user heterogeneity, their amount of links in the probe set is different. • The personalized algorithm implementation improves the recommendation performance. • Our results suggest different update frequency for users – recommendation list.

  18. Effect of Thyrotropin Suppression Therapy on Bone in Thyroid Cancer Patients.

    Science.gov (United States)

    Papaleontiou, Maria; Hawley, Sarah T; Haymart, Megan R

    2016-02-01

    The thyroid cancer incidence is rising. Despite current guidelines, controversy exists regarding the degree and duration of thyrotropin suppression therapy. Also, its potential skeletal effects remain a concern to physicians caring for thyroid cancer patients. We conducted a review of published data to evaluate existing studies focusing on the skeletal effects of thyrotropin suppression therapy in thyroid cancer patients. A systematic search of the PubMed, Ovid/Medline, and Cochrane Central Register of Controlled Trials databases was conducted. The retained studies were evaluated for methodological quality, and the study populations were categorized into premenopausal women, postmenopausal women, and men. Twenty-five pertinent studies were included. Seven studies were longitudinal and 18 were cross-sectional. Of the 25 included studies, 13 were assigned an excellent methodological quality score. Three of 5 longitudinal studies and 3 of 13 cross-sectional studies reported decreased bone mineral density (BMD) in premenopausal women; 2 of 4 longitudinal studies and 5 of 13 cross-sectional studies reported decreased BMD in postmenopausal women. The remaining studies showed no effect on BMD. The only longitudinal study of men showed bone mass loss; however, cross-sectional studies of men did not demonstrate a similar effect. Studies to date have yielded conflicting results on the skeletal effects of thyrotropin suppression therapy and a knowledge gap remains, especially for older adults and men. Existing data should be cautiously interpreted because of the variable quality and heterogeneity. Identifying groups at risk of adverse effects from thyrotropin suppression therapy will be instrumental to providing focused and tailored thyroid cancer treatment. The standard treatment for thyroid cancer includes total thyroidectomy with or without radioactive iodine ablation, often followed by thyrotropin suppression therapy. Despite current guidelines, controversy exists

  19. Mechanisms for the bone anabolic effect of parathyroid hormone treatment in humans

    DEFF Research Database (Denmark)

    Aslan, Derya; Dahl Andersen, Mille; Gede, Lene Bjerring

    2012-01-01

    . However, development of the biochemical measurement of PTH in the 1980s led us to understand the regulation of PTH secretion and calcium metabolism which subsequently paved the way for the use of PTH as an anabolic treatment of osteoporosis as, when given intermittently, it has strong anabolic effects...... in bone. This could not have taken place without the basic understanding achieved by the biochemical measurements of PTH. The stimulatory effects of PTH on bone formation have been explained by the so-called ‘anabolic window’, which means that during PTH treatment, bone formation is in excess over bone...... resorption during the first 6–18 months. This is due to the following: (1) PTH up-regulates c-fos expression in bone cells, (2) IGF is essential for PTH's anabolic effect, (3) bone lining cells are driven to differentiate into osteoblasts, (4) mesenchymal stem cells adhesion to bone surface is enhanced, (5...

  20. Hysterectomy with ovarian conservation: effect on bone mineral density

    International Nuclear Information System (INIS)

    Lareon, G.; Baillon, L.

    1997-01-01

    Full text: There are conflicting data on the long-term effects of hysterectomy with ovarian conservation on bone mineral density (BMD). Accordingly, we performed a cross-sectional study on 58 women with premenopausal hysterectomy and ovarian conservation (group 1) and 59 women with natural menopause (group 2). No subjects had disorders or medications known to interfere with bone metabolism. Patients underwent bone densitometry of the lumbar spine and hip using a Norland XR-36. By chi-squared and one-way ANOVA, there were no differences in age: 55.4± 11.0 y (1)v 57.6± 9.8 y (2); exercise, alcohol or smoking consumption, family history of osteoporosis, height: 1.61 ± 0.08m (1) v 1.61 ± 0.08m (2); weight 67.7 ± 11.3kg (1) v 68.3 kg ± 12.5 kg (2); body mass index: 30.95 (1 ) v 26.26 (2). Lumbar spine BMD was also similar for the two groups [0.95 ± 0.18g/cm 2 (1) v 0.94± 0.21 g/cm 2 (2)]. However, hysterectomy patients had a significantly lower hip BMD: 0.63 ± 0.16 g/cm 2 v 0.76 ± 0.18 g/cm 2 (p>0.001). Multivariate logistic regression showed that spine BMD was influenced by age, family history, height and weight (R 2 = 0.37), but not prior hysterectomy. Hip BMD was related to age, hysterectomy, smoking and weight (R 2 = o 45). We conclude that prior hysterectomy with ovarian conservation has an adverse effect on hip but not spine BMD

  1. Hysterectomy with ovarian conservation: effect on bone mineral density

    Energy Technology Data Exchange (ETDEWEB)

    Lareon, G.; Baillon, L. [Westmead Hospital, Westmead, NSW, (Australia). Department of Nuclear Medicine and Ultrasound

    1997-09-01

    Full text: There are conflicting data on the long-term effects of hysterectomy with ovarian conservation on bone mineral density (BMD). Accordingly, we performed a cross-sectional study on 58 women with premenopausal hysterectomy and ovarian conservation (group 1) and 59 women with natural menopause (group 2). No subjects had disorders or medications known to interfere with bone metabolism. Patients underwent bone densitometry of the lumbar spine and hip using a Norland XR-36. By chi-squared and one-way ANOVA, there were no differences in age: 55.4{+-} 11.0 y (1)v 57.6{+-} 9.8 y (2); exercise, alcohol or smoking consumption, family history of osteoporosis, height: 1.61 {+-} 0.08m (1) v 1.61 {+-} 0.08m (2); weight 67.7 {+-} 11.3kg (1) v 68.3 kg {+-} 12.5 kg (2); body mass index: 30.95 (1 ) v 26.26 (2). Lumbar spine BMD was also similar for the two groups [0.95 {+-} 0.18g/cm{sup 2} (1) v 0.94{+-} 0.21 g/cm{sup 2} (2)]. However, hysterectomy patients had a significantly lower hip BMD: 0.63 {+-} 0.16 g/cm{sup 2} v 0.76 {+-} 0.18 g/cm{sup 2} (p>0.001). Multivariate logistic regression showed that spine BMD was influenced by age, family history, height and weight (R{sup 2} = 0.37), but not prior hysterectomy. Hip BMD was related to age, hysterectomy, smoking and weight (R{sup 2} = o 45). We conclude that prior hysterectomy with ovarian conservation has an adverse effect on hip but not spine BMD.

  2. Zero-inflated count models for longitudinal measurements with heterogeneous random effects.

    Science.gov (United States)

    Zhu, Huirong; Luo, Sheng; DeSantis, Stacia M

    2017-08-01

    Longitudinal zero-inflated count data arise frequently in substance use research when assessing the effects of behavioral and pharmacological interventions. Zero-inflated count models (e.g. zero-inflated Poisson or zero-inflated negative binomial) with random effects have been developed to analyze this type of data. In random effects zero-inflated count models, the random effects covariance matrix is typically assumed to be homogeneous (constant across subjects). However, in many situations this matrix may be heterogeneous (differ by measured covariates). In this paper, we extend zero-inflated count models to account for random effects heterogeneity by modeling their variance as a function of covariates. We show via simulation that ignoring intervention and covariate-specific heterogeneity can produce biased estimates of covariate and random effect estimates. Moreover, those biased estimates can be rectified by correctly modeling the random effects covariance structure. The methodological development is motivated by and applied to the Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) study, the largest clinical trial of alcohol dependence performed in United States with 1383 individuals.

  3. The effects of strontium on bone mineral: A review on current knowledge and microanalytical approaches.

    Science.gov (United States)

    Querido, William; Rossi, Andre L; Farina, Marcos

    2016-01-01

    The interest in effects of strontium (Sr) on bone has greatly increased in the last decade due to the development of the promising drug strontium ranelate. This drug is used for treating osteoporosis, a major bone disease affecting hundreds of millions of people worldwide, especially postmenopausal women. The novelty of strontium ranelate compared to other treatments for osteoporosis is its unique effect on bone: it simultaneously promotes bone formation by osteoblasts and inhibits bone resorption by osteoclasts. Besides affecting bone cells, treatment with strontium ranelate also has a direct effect on the mineralized bone matrix. Due to the chemical similarities between Sr and Ca, a topic that has long been of particular interest is the incorporation of Sr into bones replacing Ca from the mineral phase, which is composed by carbonated hydroxyapatite nanocrystals. Several groups have analyzed the mineral produced during treatment; however, most analysis were done with relatively large samples containing numerous nanocrystals, resulting thus on data that represents an average of many crystalline domains. The nanoscale analysis of the bone apatite crystals containing Sr has only been described in a few studies. In this study, we review the current knowledge on the effects of Sr on bone mineral and discuss the methodological approaches that have been used in the field. In particular, we focus on the great potential that advanced microscopy and microanalytical techniques may have on the detailed analysis of the nanostructure and composition of bone apatite nanocrystals produced during treatment with strontium ranelate. Copyright © 2015. Published by Elsevier Ltd.

  4. Effects of low-intensity pulsed ultrasound on new trabecular bone during bone-tendon junction healing in a rabbit model: a synchrotron radiation micro-CT study.

    Directory of Open Access Journals (Sweden)

    Hongbin Lu

    Full Text Available This study was designed to evaluate the effects of low-intensity pulsed ultrasound on bone regeneration during the bone-tendon junction healing process and to explore the application of synchrotron radiation micro computed tomography in three dimensional visualization of the bone-tendon junction to evaluate the microarchitecture of new trabecular bone. Twenty four mature New Zealand rabbits underwent partial patellectomy to establish a bone-tendon junction injury model at the patella-patellar tendon complex. Animals were then divided into low-intensity pulsed ultrasound treatment (20 min/day, 7 times/week and placebo control groups, and were euthanized at week 8 and 16 postoperatively (n = 6 for each group and time point. The patella-patellar tendon specimens were harvested for radiographic, histological and synchrotron radiation micro computed tomography detection. The area of the newly formed bone in the ultrasound group was significantly greater than that of control group at postoperative week 8 and 16. The high resolution three dimensional visualization images of the bone-tendon junction were acquired by synchrotron radiation micro computed tomography. Low-intensity pulsed ultrasound treatment promoted dense and irregular woven bone formation at week 8 with greater bone volume fraction, number and thickness of new trabecular bone but with lower separation. At week 16, ultrasound group specimens contained mature lamellar bone with higher bone volume fraction and thicker trabeculae than that of control group; however, there was no significant difference in separation and number of the new trabecular bone. This study confirms that low-intensity pulsed ultrasound treatment is able to promote bone formation and remodeling of new trabecular bone during the bone-tendon junction healing process in a rabbit model, and the synchrotron radiation micro computed tomography could be applied for three dimensional visualization to quantitatively evaluate

  5. [Experimental study of the effect of new bone formation on new type artificial bone composed of bioactive ceramics].

    Science.gov (United States)

    Zhu, Minghua; Zeng, Yi; Sun, Tao; Peng, Qiang

    2005-03-15

    To investigate the osteogenic potential of four kinds of new bioactive ceramics combined with bovine bone morphogenetic proteins (BMP) and to explore the feasibility of using compounds as bone substitute material. Ninety-six rats were divided into 4 groups (24 in each group). BMP was combined with hydroxyapatite (HA), tricalcium phosphate (TCP), fluoridated-HA (FHA), and collagen-HA(CHA) respectively. The left thighs of the rats implanted with HA/BMP, TCP/BMP, FHA/BMP, and CHA/BMP were used as experimental groups. The right thighs of the rats implanted with HA, TCP, CHA, and decalcified dentin matrix (DDM) were used as control groups. The rats were sacrificed 1, 3, 5 and 7 weeks after implantation and bone induction was estimated by alkaline phosphatase (ALP), phosphorus (P), and total protein (TP) measurement. The histological observation and electronic microscope scanning of the implants were also made. The cartilage growth in the 4 experimental groups and the control group implanted with DDM was observed 1 week after operation and fibrous connective tissues were observed in the other 3 control groups. 3 weeks after implantation, lamellar bone with bone marrow and positive reaction in ALP stain were observed in the 4 experimental groups. No bone formation or positive reaction in ALP stain were observed in the control groups. The amount of ALP activity, P value, and new bone formation in the experimental groups were higher than those in the control group(P < 0.05). The amount of ALP activity, P value, and new bone formation in TCP/BMP group were higher than those in HA/BMP, CHA/BMP and FHA/BMP groups (P < 0.05). There was no significant difference in TP between the BMP treatment group and the control groups. From 5th to 7th week, new bone formation, histochemistry evaluation, and the level of ALP, P, TP value were as high as those in the 3rd week. New composite artificial bone of TCP/BMP, HA/BMP, CHA/BMP, and FHA/BMP all prove to be effective, but TCP/BMP is the

  6. Application and Effect of Mobiletype-Bone Health Intervention in Korean Young Adult Women with Low Bone Mass: A Randomized Control Trial

    Directory of Open Access Journals (Sweden)

    Young-Joo Park, PhD, RN

    2017-03-01

    Conclusion: Although both experimental groups exhibited positive outcomes in regards to the promotion of bone health, this study did not show an additional effect of the mobile application on self-management ability for the promotion of bone health. Nonetheless, the SbFb application is very meaningful as it is the first application developed with the aim of improving women's bone health.

  7. On the validity of effective formulations for transport through heterogeneous porous media

    Science.gov (United States)

    de Dreuzy, Jean-Raynald; Carrera, Jesus

    2016-04-01

    Geological heterogeneity enhances spreading of solutes and causes transport to be anomalous (i.e., non-Fickian), with much less mixing than suggested by dispersion. This implies that modeling transport requires adopting either stochastic approaches that model heterogeneity explicitly or effective transport formulations that acknowledge the effects of heterogeneity. A number of such formulations have been developed and tested as upscaled representations of enhanced spreading. However, their ability to represent mixing has not been formally tested, which is required for proper reproduction of chemical reactions and which motivates our work. We propose that, for an effective transport formulation to be considered a valid representation of transport through heterogeneous porous media (HPM), it should honor mean advection, mixing and spreading. It should also be flexible enough to be applicable to real problems. We test the capacity of the multi-rate mass transfer (MRMT) model to reproduce mixing observed in HPM, as represented by the classical multi-Gaussian log-permeability field with a Gaussian correlation pattern. Non-dispersive mixing comes from heterogeneity structures in the concentration fields that are not captured by macrodispersion. These fine structures limit mixing initially, but eventually enhance it. Numerical results show that, relative to HPM, MRMT models display a much stronger memory of initial conditions on mixing than on dispersion because of the sensitivity of the mixing state to the actual values of concentration. Because MRMT does not restitute the local concentration structures, it induces smaller non-dispersive mixing than HPM. However long-lived trapping in the immobile zones may sustain the deviation from dispersive mixing over much longer times. While spreading can be well captured by MRMT models, in general non-dispersive mixing cannot.

  8. Bone Quality: The Mechanical Effects of Microarchitecture and Matrix Properties

    NARCIS (Netherlands)

    J.S. Day (Judd)

    2005-01-01

    textabstractIn this body of work we have examined some of the current concepts pertaining to the relation between bone mass, bone quality and the mechanical properties of bone. In our first series of studies we used a model of human osteoarthritis to investigate the implications of changes in the

  9. Effect of weightlessness on mineral saturation of bone tissue

    Science.gov (United States)

    Krasnykh, I. G.

    1975-01-01

    X-ray photometry of bone density established dynamic changes in mineral saturation of bone tissues for Soyuz spacecraft and Salyut orbital station crews. Calcaneus optical bone densities in all crew members fell below initial values; an increase in spacecrew exposure time to weightlessness conditions also increased the degree of decalcification. Demineralization under weightlessness conditions took place at a higher rate than under hypodynamia.

  10. Effects of mechanical repetitive load on bone quality around implants in rat maxillae.

    Directory of Open Access Journals (Sweden)

    Yusuke Uto

    Full Text Available Greater understanding and acceptance of the new concept "bone quality", which was proposed by the National Institutes of Health and is based on bone cells and collagen fibers, are required. The novel protein Semaphorin3A (Sema3A is associated with osteoprotection by regulating bone cells. The aims of this study were to investigate the effects of mechanical loads on Sema3A production and bone quality based on bone cells and collagen fibers around implants in rat maxillae. Grade IV-titanium threaded implants were placed at 4 weeks post-extraction in maxillary first molars. Implants received mechanical loads (10 N, 3 Hz for 1800 cycles, 2 days/week for 5 weeks from 3 weeks post-implant placement to minimize the effects of wound healing processes by implant placement. Bone structures, bone mineral density (BMD, Sema3A production and bone quality based on bone cells and collagen fibers were analyzed using microcomputed tomography, histomorphometry, immunohistomorphometry, polarized light microscopy and birefringence measurement system inside of the first and second thread (designated as thread A and B, respectively, as mechanical stresses are concentrated and differently distributed on the first two threads from the implant neck. Mechanical load significantly increased BMD, but not bone volume around implants. Inside thread B, but not thread A, mechanical load significantly accelerated Sema3A production with increased number of osteoblasts and osteocytes, and enhanced production of both type I and III collagen. Moreover, mechanical load also significantly induced preferential alignment of collagen fibers in the lower flank of thread B. These data demonstrate that mechanical load has different effects on Sema3A production and bone quality based on bone cells and collagen fibers between the inside threads of A and B. Mechanical load-induced Sema3A production may be differentially regulated by the type of bone structure or distinct stress distribution

  11. Effects of hypogonadism on bone metabolism in female adolescents and young adults.

    Science.gov (United States)

    Misra, Madhusmita

    2012-01-24

    Gonadal steroids, including androgens and oestrogens, play a critical part in bone metabolism, and conditions associated with a deficiency of gonadal steroids can reduce BMD in adults and impair bone accrual in adolescents. In addition, other associated hormone alterations, for example, insulin-like growth factor 1 deficiency or high cortisol levels, can further exacerbate the effect of hypogonadism on bone metabolism, as can factors such as calcium and vitamin D deficiency, low body weight and exercise status. This Review discusses the effects of different hypogonadal states on bone metabolism in female adolescents and young adults, with particular emphasis on conditions associated with low energy availability, such as anorexia nervosa and athletic amenorrhoea, in which many factors other than hypogonadism affect bone. In contrast to most hypogonadal conditions, in which replacement of gonadal steroids is sufficient to normalize bone accrual rates and BMD, gonadal steroid replacement may not be sufficient to normalize bone metabolism in these states of energy deficit.

  12. Positive effects of bisphosphonates on bone and muscle in a mouse model of Duchenne muscular dystrophy.

    Science.gov (United States)

    Yoon, Sung-Hee; Sugamori, Kim S; Grynpas, Marc D; Mitchell, Jane

    2016-01-01

    Patients with Duchenne muscular dystrophy are at increased risk of decreased bone mineral density and bone fracture as a result of inactivity. To determine if antiresorptive bisphosphonates could improve bone quality and their effects on muscle we studied the Mdx mouse, treated with pamidronate during peak bone growth at 5 and 6 weeks of age, and examined the outcome at 13 weeks of age. Pamidronate increased cortical bone architecture and strength in femurs with increased resistance to fracture. While overall long bone growth was not affected by pamidronate, there was significant inhibition of remodeling in metaphyseal trabecular bone with evidence of residual calcified cartilage. Pamidronate treatment had positive effects on skeletal muscle in the Mdx mice with decreased serum and muscle creatine kinase and evidence of improved muscle histology and grip strength. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Effect of hormone replacement therapy on the bone mass and urinary excretion of pyridinium cross-links

    OpenAIRE

    Pardini,Dolores Perovano; Sabino,Anibal Tagliaferri; Meneses,Ana Maria; Kasamatsu,Teresa; Vieira,José Gilberto Henriques

    2000-01-01

    CONTEXT: The menopause accelerates bone loss and is associated with an increased bone turnover. Bone formation may be evaluated by several biochemical markers. However, the establishment of an accurate marker for bone resorption has been more difficult to achieve. OBJECTIVE: To study the effect of hormone replacement therapy (HRT) on bone mass and on the markers of bone resorption: urinary excretion of pyridinoline and deoxypyridinoline. DESIGN: Cohort correlational study. SETTING: Academic...

  14. Stability of faults with heterogeneous friction properties and effective normal stress

    Science.gov (United States)

    Luo, Yingdi; Ampuero, Jean-Paul

    2018-05-01

    Abundant geological, seismological and experimental evidence of the heterogeneous structure of natural faults motivates the theoretical and computational study of the mechanical behavior of heterogeneous frictional fault interfaces. Fault zones are composed of a mixture of materials with contrasting strength, which may affect the spatial variability of seismic coupling, the location of high-frequency radiation and the diversity of slip behavior observed in natural faults. To develop a quantitative understanding of the effect of strength heterogeneity on the mechanical behavior of faults, here we investigate a fault model with spatially variable frictional properties and pore pressure. Conceptually, this model may correspond to two rough surfaces in contact along discrete asperities, the space in between being filled by compressed gouge. The asperities have different permeability than the gouge matrix and may be hydraulically sealed, resulting in different pore pressure. We consider faults governed by rate-and-state friction, with mixtures of velocity-weakening and velocity-strengthening materials and contrasts of effective normal stress. We systematically study the diversity of slip behaviors generated by this model through multi-cycle simulations and linear stability analysis. The fault can be either stable without spontaneous slip transients, or unstable with spontaneous rupture. When the fault is unstable, slip can rupture either part or the entire fault. In some cases the fault alternates between these behaviors throughout multiple cycles. We determine how the fault behavior is controlled by the proportion of velocity-weakening and velocity-strengthening materials, their relative strength and other frictional properties. We also develop, through heuristic approximations, closed-form equations to predict the stability of slip on heterogeneous faults. Our study shows that a fault model with heterogeneous materials and pore pressure contrasts is a viable framework

  15. Effects of a phosphocitrate analogue on osteophyte, subchondral bone advance, and bone marrow lesions in Hartley guinea pigs

    Science.gov (United States)

    Kiraly, A. J.; Sun, A. R.; Cox, M.; Mauerhan, D. R.; Hanley, E. N.

    2018-01-01

    Objectives The objectives of this study were: 1) to examine osteophyte formation, subchondral bone advance, and bone marrow lesions (BMLs) in osteoarthritis (OA)-prone Hartley guinea pigs; and 2) to assess the disease-modifying activity of an orally administered phosphocitrate ‘analogue’, Carolinas Molecule-01 (CM-01). Methods Young Hartley guinea pigs were divided into two groups. The first group (n = 12) had drinking water and the second group (n = 9) had drinking water containing CM-01. Three guinea pigs in each group were euthanized at age six, 12, and 18 months, respectively. Three guinea pigs in the first group were euthanized aged three months as baseline control. Radiological, histological, and immunochemical examinations were performed to assess cartilage degeneration, osteophyte formation, subchondral bone advance, BMLs, and the levels of matrix metalloproteinse-13 (MMP13) protein expression in the knee joints of hind limbs. Results In addition to cartilage degeneration, osteophytes, subchondral bone advance, and BMLs increased with age. Subchondral bone advance was observed as early as six months, whereas BMLs and osteophytes were both observed mainly at 12 and 18 months. Fibrotic BMLs were found mostly underneath the degenerated cartilage on the medial side. In contrast, necrotic BMLs were found almost exclusively in the interspinous region. Orally administered CM-01 decreased all of these pathological changes and reduced the levels of MMP13 expression. Conclusion Subchondral bone may play a role in cartilage degeneration. Subchondral bone changes are early events; formation of osteophytes and BMLs are later events in the OA disease process. Carolinas Molecule-01 is a promising small molecule candidate to be tested as an oral disease-modifying drug for human OA therapy. Cite this article: Y. Sun, A. J. Kiraly, A. R. Sun, M. Cox, D. R. Mauerhan, E. N. Hanley Jr. Effects of a phosphocitrate analogue on osteophyte, subchondral bone advance, and

  16. Effects of growth hormone and low dose estrogen on bone growth and turnover in long bones of hypophysectomized rats

    Science.gov (United States)

    Kidder, L. S.; Schmidt, I. U.; Evans, G. L.; Turner, R. T.

    1997-01-01

    Pituitary hormones are recognized as critical to longitudinal growth, but their role in the radial growth of bone and in maintaining cancellous bone balance are less clear. This investigation examines the histomorphometric effects of hypophysectomy (Hx) and ovariectomy (OVX) and the subsequent replacement of growth hormone (GH) and estrogen (E), in order to determine the effects and possible interactions between these two hormones on cortical and cancellous bone growth and turnover. The replacement of estrogen is of interest since Hx results in both pituitary and gonadal hormone insufficiencies, with the latter being caused by the Hx-associated reduction in follicle stimulating hormone (FSH). All hypophysectomized animals received daily supplements of hydrocortisone (500 microg/kg) and L-thyroxine (10 microg/kg), whereas intact animals received daily saline injections. One week following surgery, hypophysectomized animals received either daily injections of low-dose 17 beta-estradiol (4.8 microg/kg s.c.), 3 X/d recombinant human GH (2 U/kg s.c.), both, or saline for a period of two weeks. Flurochromes were administered at weekly intervals to label bone matrix undergoing mineralization. Whereas Hx resulted in reductions in body weight, uterine weight, and tibial length, OVX significantly increased body weight and tibial length, while reducing uterine weight. The combination of OVX and Hx resulted in values similar to Hx alone. Treatment with GH normalized body weight and bone length, while not affecting uterine weight in hypophysectomized animals. Estrogen increased uterine weight, while not impacting longitudinal bone growth and reduced body weight. Hypophysectomy diminished tibial cortical bone area through reductions in both mineral appositional rate (MAR) and bone formation rate (BFR). While E had no effect, GH increased both MAR and BFR, though not to sham-operated (control) levels. Hypophysectomy reduced proximal tibial trabecular number and cancellous bone

  17. Evaluation of aquifer heterogeneity effects on river flow loss using a transition probability framework

    Science.gov (United States)

    Engdahl, N.B.; Vogler, E.T.; Weissmann, G.S.

    2010-01-01

    River-aquifer exchange is considered within a transition probability framework along the Rio Grande in Albuquerque, New Mexico, to provide a stochastic estimate of aquifer heterogeneity and river loss. Six plausible hydrofacies configurations were determined using categorized drill core and wetland survey data processed through the TPROGS geostatistical package. A base case homogeneous model was also constructed for comparison. River loss was simulated for low, moderate, and high Rio Grande stages and several different riverside drain stage configurations. Heterogeneity effects were quantified by determining the mean and variance of the K field for each realization compared to the root-mean-square (RMS) error of the observed groundwater head data. Simulation results showed that the heterogeneous models produced smaller estimates of loss than the homogeneous approximation. Differences between heterogeneous and homogeneous model results indicate that the use of a homogeneous K in a regional-scale model may result in an overestimation of loss but comparable RMS error. We find that the simulated river loss is dependent on the aquifer structure and is most sensitive to the volumetric proportion of fines within the river channel. Copyright 2010 by the American Geophysical Union.

  18. Effects of Heterogeneity in Residential Preferences on an Agent-Based Model of Urban Sprawl

    Directory of Open Access Journals (Sweden)

    Daniel G. Brown

    2006-06-01

    Full Text Available The ability of agent-based models (ABMs to represent heterogeneity in the characteristics and behaviors of actors enables analyses about the implications of this heterogeneity for system behavior. The importance of heterogeneity in the specification of ABMs, however, creates new demands for empirical support. An earlier analysis of a survey of residential preferences within southeastern Michigan revealed seven groups of residents with similar preferences on similar characteristics of location. In this paper, we present an ABM that represents the process of residential development within an urban system and run it for a hypothetical pattern of environmental variation. Residential locations are selected by residential agents, who evaluate locations on the basis of preference for nearness to urban services, including jobs, aesthetic quality of the landscape, and their similarity to their neighbors. We populate our ABM with a population of residential preferences drawn from the survey results in five different ways: (1 preferences drawn at random; (2 equal preferences based on the mean from the entire survey sample; (3 preferences drawn from a single distribution, whose mean and standard deviation are derived from the survey sample; (4 equal preferences within each of seven groups, based on the group means; and (5 preferences drawn from distributions for each of seven groups, defined by group means and standard deviations. Model sensitivity analysis, based on multiple runs of our model under each case, revealed that adding heterogeneity to agents has a significant effect on model outcomes, measured by aggregate patterns of development sprawl and clustering.

  19. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    Science.gov (United States)

    Shi, Chengyu; Guo, Bingqi; Cheng, Chih-Yao; Eng, Tony; Papanikolaou, Nikos

    2010-09-01

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent™ x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95

  20. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos [Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, TX 78229 (United States); Cheng, Chih-Yao, E-mail: shic@uthscsa.ed [Radiation Oncology Department, Oklahoma University Health Science Center, Oklahoma, OK 73104 (United States)

    2010-09-21

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V{sub 100} reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as

  1. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    International Nuclear Information System (INIS)

    Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos; Cheng, Chih-Yao

    2010-01-01

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V 100 reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95

  2. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration

    International Nuclear Information System (INIS)

    Chen, Zonggang; Kang, Lingzhi; Meng, Qing-Yuan; Liu, Huanye; Wang, Zhaoliang; Guo, Zhongwu; Cui, Fu-Zhai

    2014-01-01

    The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites. - Highlights: • The nHAC/CSH composite can be as an injectable bone repair material. • The L/S ratio and nHAC content have a significant effect on material degradability. • The degradability of bone materials can be regulated to match tissue repair. • The regulable degradability will further improve the workability of bone materials

  3. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zonggang, E-mail: chenzg@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kang, Lingzhi [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Meng, Qing-Yuan [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, Huanye [Department of Prosthodontics, School of Stomatology, China Medical University, Shenyang 110001 (China); Wang, Zhaoliang [Jinan Military General Hospital of PLA, Jinan 250031 (China); Guo, Zhongwu, E-mail: zwguo@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Cui, Fu-Zhai, E-mail: cuifz@mail.tsinghua.edu.cn [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-12-01

    The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites. - Highlights: • The nHAC/CSH composite can be as an injectable bone repair material. • The L/S ratio and nHAC content have a significant effect on material degradability. • The degradability of bone materials can be regulated to match tissue repair. • The regulable degradability will further improve the workability of bone materials.

  4. Heterogeneity in the response to gasoline prices: Evidence from Pennsylvania and implications for the rebound effect

    International Nuclear Information System (INIS)

    Gillingham, Kenneth; Jenn, Alan; Azevedo, Inês M.L.

    2015-01-01

    The consumer response to changing gasoline prices has long interested economists and policymakers, for it has important implications for the effects of gasoline taxation and vehicle energy efficiency policies. This study examines both the elasticity of driving with respect to changing gasoline prices and heterogeneity in this elasticity by geography, the fuel economy of the vehicle, and the age of the vehicle. We use detailed annual vehicle-level emissions inspection test data from Pennsylvania that include odometer readings, inspection zip codes, and extensive vehicle characteristics. We estimate a short-run gasoline price elasticity of driving demand of − 0.10, and find substantial heterogeneity in this responsiveness. The elasticity is largely driven by low fuel economy vehicles, as well as vehicles between 3 and 7 years old. Our findings help reconcile some of the recent literature and provide guidance on the magnitude of the direct rebound effect from light duty vehicle energy efficiency policies.

  5. Widespread differential maternal and paternal genome effects on fetal bone phenotype at mid-gestation.

    Science.gov (United States)

    Xiang, Ruidong; Lee, Alice M C; Eindorf, Tanja; Javadmanesh, Ali; Ghanipoor-Samami, Mani; Gugger, Madeleine; Fitzsimmons, Carolyn J; Kruk, Zbigniew A; Pitchford, Wayne S; Leviton, Alison J; Thomsen, Dana A; Beckman, Ian; Anderson, Gail I; Burns, Brian M; Rutley, David L; Xian, Cory J; Hiendleder, Stefan

    2014-11-01

    Parent-of-origin-dependent (epi)genetic factors are important determinants of prenatal development that program adult phenotype. However, data on magnitude and specificity of maternal and paternal genome effects on fetal bone are lacking. We used an outbred bovine model to dissect and quantify effects of parental genomes, fetal sex, and nongenetic maternal effects on the fetal skeleton and analyzed phenotypic and molecular relationships between fetal muscle and bone. Analysis of 51 bone morphometric and weight parameters from 72 fetuses recovered at day 153 gestation (54% term) identified six principal components (PC1-6) that explained 80% of the variation in skeletal parameters. Parental genomes accounted for most of the variation in bone wet weight (PC1, 72.1%), limb ossification (PC2, 99.8%), flat bone size (PC4, 99.7%), and axial skeletal growth (PC5, 96.9%). Limb length showed lesser effects of parental genomes (PC3, 40.8%) and a significant nongenetic maternal effect (gestational weight gain, 29%). Fetal sex affected bone wet weight (PC1, p maternal genome effects on bone wet weight (74.1%, p paternal genome controlled limb ossification (95.1%, p maternal genome effects on growth plate height (98.6%, p maternal genome effects on fetal serum 25-hydroxyvitamin D (96.9%, p paternal genome effects on alkaline phosphatase (90.0%, p maternally controlled bone wet weight and paternally controlled limb ossification, respectively. Bone wet weight and flat bone size correlated positively with muscle weight (r = 0.84 and 0.77, p maternally expressed H19 regulates growth factors by miRNA interference, this suggests muscle-bone interaction via epigenetic factors. © 2014 American Society for Bone and Mineral Research.

  6. Effect of heterogeneity in a horizontal well with multiple fractures on the long term forecast in shale gas reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Nobakht, M.; Ambrose, R.; Clarkson, C.R. [Society of Petroleum Engineers (Canada)

    2011-07-01

    Multiple fracture horizontal wells (MFHWs) are the most popular type of method used for exploiting shale gas reservoirs. When analyzing MFHW's a homogeneous completion model is often used, but this rarely occurs in the field. This paper develops a hybrid method for forecasting MFHWs based on a heterogeneous completion and investigates the effect of completion heterogeneity on production forecasts. First, a current forecasting method for homogeneous completions was modified for heterogeneous completions. The new forecasting method was then validated using a numerical simulation. A relationship between Arps' hyperbolic decline exponent and the heterogeneity of a completion for a particular case was then developed. Lastly, a field case was analyzed to compare the impact of forecasting with and without taking a heterogeneous completion into consideration. Through analysis and simulations this paper found that the long-term forecast of MFHWs can be greatly impacted should heterogeneity of the completion be ignored.

  7. Experimental Evaluation of the Effectiveness of Demineralized Bone Matrix and Collagenated Heterologous Bone Grafts Used Alone or in Combination with Platelet-Rich Fibrin on Bone Healing in Sinus Floor Augmentation.

    Science.gov (United States)

    Peker, Elif; Karaca, Inci Rana; Yildirim, Benay

    2016-01-01

    The aim of this study was an experimental evaluation of the effectiveness of demineralized bone matrix (DBM) and collagenated heterologous bone graft (CHBG) used alone or in combination with platelet-rich fibrin on bone healing in sinus floor augmentation procedures. In this study, 36 New Zealand rabbits were used. The bilateral sinus elevation was performed, and 72 defects were obtained. The rabbit maxillary sinuses were divided into four groups according to the augmentation biomaterials obtained: demineralized bone matrix (Grafton DBM Putty, Osteotech; DBM group), DBM combined with platelet-rich fibrin (PRF; DBM + PRF group), collagenated heterologous bone graft (CHBG; Apatos Mix, OsteoBiol, Tecnoss; CHBG group), CHBG combined with PRF (CHBG + PRF group). All groups were sacrificed at 2, 4, and 8 weeks after surgery for histologic, histomorphometric, and immunohistochemical analyses. The inflammatory reaction was moderate to intense at the second week in all groups and declined from 2 to 8 weeks. New bone formation was started at the second week and increased from 2 to 8 weeks in all groups. There was no significant difference in bone formation between the experimental groups that used PRF mixed graft material and control groups that used only graft material. The percentage of new bone formation showed a significant difference in DBM groups and DBM + PRF groups compared with other groups. There were osteoclasts around all the bone graft materials used, but the percentage of residual graft particles was significantly higher in CHBG groups and CHBG + PRF groups at the eighth week. There is no beneficial effect of the application of PRF in combination with demineralized bone matrix or collagenated heterologous bone graft on bone formation in sinus floor augmentation. The results of this study showed that both collagenated heterologous bone graft and demineralized bone matrix have osteoconductive properties, but demineralized bone matrix showed more bone formation

  8. PTH prevents the adverse effects of focal radiation on bone architecture in young rats.

    Science.gov (United States)

    Chandra, Abhishek; Lan, Shenghui; Zhu, Ji; Lin, Tiao; Zhang, Xianrong; Siclari, Valerie A; Altman, Allison R; Cengel, Keith A; Liu, X Sherry; Qin, Ling

    2013-08-01

    Radiation therapy is a common treatment regimen for cancer patients. However, its adverse effects on the neighboring bone could lead to fractures with a great impact on quality of life. The underlying mechanism is still elusive and there is no preventive or curative solution for this bone loss. Parathyroid hormone (PTH) is a current therapy for osteoporosis that has potent anabolic effects on bone. In this study, we found that focal radiation from frequent scans of the right tibiae in 1-month-old rats by micro-computed tomography severely decreased trabecular bone mass and deteriorated bone structure. Interestingly, PTH daily injections remarkably improved trabecular bone in the radiated tibiae with increases in trabecular number, thickness, connectivity, structure model index and stiffness, and a decrease in trabecular separation. Histomorphometric analysis revealed that radiation mainly decreased the number of osteoblasts and impaired their mineralization activity but had little effects on osteoclasts. PTH reversed these adverse effects and greatly increased bone formation to a similar level in both radiated and non-radiated bones. Furthermore, PTH protects bone marrow mesenchymal stem cells from radiation-induced damage, including a decrease in number and an increase in adipogenic differentiation. While radiation generated the same amount of free radicals in the bone marrow of vehicle-treated and PTH-treated animals, the percentage of apoptotic bone marrow cells was significantly attenuated in the PTH group. Taken together, our data demonstrate a radioprotective effect of PTH on bone structure and bone marrow and shed new light on a possible clinical application of anabolic treatment in radiotherapy. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Flow and transport in unsaturated fractured rock: Effects of multiscale heterogeneity of hydrogeologic properties

    International Nuclear Information System (INIS)

    Zhou, Quanlin; Liu, Hui-Hai; Bodvarsson, Gudmundur S.; Oldenburg, Curtis M.

    2002-01-01

    The heterogeneity of hydrogeologic properties at different scales may have different effects on flow and transport processes in a subsurface system. A model for the unsaturated zone of Yucca Mountain, Nevada, is developed to represent complex heterogeneity at two different scales: (1) layer scale corresponding to geologic layering and (2) local scale. The layer-scale hydrogeologic properties are obtained using inverse modeling, based on the available measurements collected from the Yucca Mountain site. Calibration results show a significant lateral and vertical variability in matrix and fracture properties. Hydrogeologic property distributions in a two-dimensional, vertical cross section of the site are generated by combining the average layer-scale matrix and fracture properties with local-scale perturbations generated using a stochastic simulation method. The unsaturated water flow and conservative (nonsorbing) tracer transport through the cross section are simulated for different sets of matrix and fracture property fields. Comparison of simulation results indicates that the local-scale heterogeneity of matrix and fracture properties has a considerable effect on unsaturated flow processes, leading to fast flow paths in fractures and the matrix. These paths shorten the travel time of a conservative tracer from the source (repository) horizon in the unsaturated zone to the water table for small fractions of total released tracer mass. As a result, the local-scale heterogeneity also has a noticeable effect on global tracer transport processes, characterized by an average breakthrough curve at the water table, especially at the early arrival time of tracer mass. However, the effect is not significant at the later time after 20 percent tracer mass reaches the water table. The simulation results also verify that matrix diffusion plays an important role in overall solute transport processes in the unsaturated zone at Yucca Mountain

  10. Page 1 Heterogeneous doping effects in KC-AlO composites 213 of ...

    Indian Academy of Sciences (India)

    Heterogeneous doping effects in KC-AlO composites 213 of Al-O in KCl at 500°C for three different sizes of Al-O particles (0-05, 0-3 and. 1-0 um). The figure shows that as the concentration of Al Os increases, the conductivity increases slowly initially, then rather rapidly before it peaks at a 45mol%. Al2O. Moreover, as the ...

  11. Approach to reducing the effect of bone-coal power station on radiation environment

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effect of two bone-coal power stations (6 MWe) on environment wasinvestigated within the scope of the dose contribution caused by various radionucildes in different ways. It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder (BCC), soot and ash in the catchers.

  12. Effect of Clothing on Measurement of Bone Mineral Density.

    Science.gov (United States)

    McNamara, Elizabeth A; Feldman, Anna Z; Malabanan, Alan O; Abate, Ejigayehu G; Whittaker, LaTarsha G; Yano-Litwin, Amanda; Dorazio, Jolene; Rosen, Harold N

    2016-01-01

    It is unknown whether allowing patients to have BMD (bone mineral density) studies acquired while wearing radiolucent clothing adlib contributes appreciably to the measurement error seen. To examine this question, a spine phantom was scanned 30 times without any clothing, while draped with a gown, and while draped with heavy winter clothing. The effect on mean BMD and on SD (standard deviation) was assessed. The effect of clothing on mean or SD of the area was not significant. The effect of clothing on mean and SD for BMD was small but significant and was around 1.6% for the mean. However, the effect on BMD precision was much more clinically important. Without clothing the spine phantom had an least significant change of 0.0077 gm/cm(2), while when introducing variability of clothing the least significant change rose as high as 0.0305 gm/cm(2). We conclude that, adding clothing to the spine phantom had a small but statistically significant effect on the mean BMD and on variance of the measurement. It is unlikely that the effect on mean BMD has any clinical significance, but the effect on the reproducibility (precision) of the result is likely clinically significant. Copyright © 2016 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  13. Effect of zoledronic acid on bone density and markers of bone turnover in a community clinic.

    Science.gov (United States)

    Lim, Ria; Zailskas, Susan; Goldsby, Tashauna U; Lukens, Carrie; Muravev, Rostislav; Dulipsingh, Latha

    2013-01-01

    This study aims to document the efficacy of zoledronic acid by comparing bone densities and markers of bone turnover, in patients with osteoporosis. Bone mineral density (BMD) and urinary N-telopeptide, a marker of bone turnover, were compared before and after treatment with intravenous zoledronic acid. 52 participants had atleast two doses of zoledronic acid over 36 months. Significant increases in BMD were found in the spine (t=4.38, Pturnover marker N-telopeptide (t=3.30, P=0.002). Small but significant correlations were determined between prior steroid use and change in BMD in the spine (r=0.35, P<0.05), and family history of osteoporosis and change in BMD in the right femur (r=0.38, P<0.05). Annual infusions of zoledronic acid for at least two years, revealed a significant increase in bone density at the spine and a decrease in urinary N-telopeptide in patients treated at our center.

  14. The effect of patient age on bone formation using a fully synthetic nanocrystalline bone augmentation material in maxillary sinus grafting.

    Science.gov (United States)

    Wolf, Michael; Wurm, Alexander; Heinemann, Friedhelm; Gerber, Thomas; Reichert, Christoph; Jäger, Andreas; Götz, Werner

    2014-01-01

    Maxillary sinus floor augmentation is a treatment that has been proposed for patients in whom the alveolar bone height is insufficient. This procedure is commonly used in patients aged 40 to 70 years and older. However, little information exists whether the factor of age might influence the outcome of augmentation procedures. The aim of this study was to investigate whether the patient's age has an effect on bone formation and incorporation in maxillary sinus floor augmentation procedures. A fully synthetic nanocrystalline bone augmentation material (NanoBone, Artoss) was used for sinus floor augmentation in patients with a subantral vertical bone height of at least 3 mm and maximum of 7 mm. After 7 months healing time, biopsy specimens were taken and were divided into two groups according to the patient's age. Exclusion criteria were poor general health (eg, severe renal/and or liver disease), history of a radiotherapy in the head region, chemotherapy at the time of surgical procedure, noncompensated diabetes mellitus, symptoms of a maxillary sinus disease, active periodontal or systemic diseases, smoking, and poor oral hygiene. Histologic analyses with hematoxylin-eosin stain were performed. Multinucleated osteoclast-like cells were identified by histochemical staining (tartrate-resistant acid phosphatase [TRAP]). Quantitative and age-dependent assessment of bone formation, residual bone grafting material, and soft tissue formation following sinus augmentation was performed using histomorphometric analysis and the Bonferroni adjustment of the Student t test. Twenty biopsy specimens from 17 patients were taken and divided into two groups according to age (group 1: 41 to 52 years; group 2: 66 to 71 years) containing 10 specimens each, which were analyzed in triplicate resulting in a total of 30 specimens per group. A regeneration process with varying amounts of newly formed bone surrounded by marrow-like tissue was present in all augmented regions. No signs of

  15. Effect of Denosumab on Peripheral Compartmental Bone Density, Microarchitecture and Estimated Bone Strength in De Novo Kidney Transplant Recipients.

    Science.gov (United States)

    Bonani, Marco; Meyer, Ursina; Frey, Diana; Graf, Nicole; Bischoff-Ferrari, Heike A; Wüthrich, Rudolf P

    2016-01-01

    In a randomized controlled clinical trial in kidney transplant recipients (NCT01377467) we have recently shown that RANKL inhibition with denosumab significantly improved areal bone mineral density (aBMD) when given during the first year after transplantation. The effect of denosumab on skeletal microstructure and bone strength in kidney transplant recipients is not known. The purpose of the present bone microarchitecture ancillary study was to investigate high-resolution peripheral quantitative computed tomography (HRpQCT) data from the distal tibia and distal radius in 24 study patients that had been randomized to receive either two injections of denosumab 60 mg at baseline and after 6 months (n=10) or no treatment (n=14). Consistent with the full trial findings, denosumab reduced biomarkers of bone turnover, and significantly increased aBMD at the lumbar spine (median difference of 4.7%; 95% confidence interval [CI] 2.6 - 7.8; pBone quality as assessed by total and cortical volumetric bone mineral density (Tot. vBMD, Ct.vBMD) and cortical thickness (Ct.Th) increased significantly at the tibia, while changes at the radius were less pronounced. The trabecular volumetric BMD (Tb.vBMD), thickness (Tb. Th), separation (Tb.Sp) and number (Tb.N) and the cortical porosity (Ct.Po) at the tibia and the radius did not significantly change in both treatment groups. Micro-finite element analysis (µFEA) showed that bone stiffness increased significantly at the tibia (median difference 5.6%; 95% CI 1.8% - 9.2%; p=0.002) but not at the radius (median difference 2.9%, 95% CI -3.7% - 9.1%; p=0.369). Likewise, failure load increased significantly at the tibia (median difference 5.1%; 95% CI 2.1% - 8.1%; p=0.002) but not at the radius (median difference 2.4%, 95% CI -3.2% - 8.5%; p=0.336). These findings demonstrate that denosumab improves bone density and bone quality in first-year kidney transplant recipients at risk to develop osteoporosis. © 2016 The Author(s) Published by S

  16. Hypovitaminosis D and hyperparathyroidism: effects on bone turnover and bone mineral density among perinatally HIV-infected adolescents.

    Science.gov (United States)

    Sudjaritruk, Tavitiya; Bunupuradah, Torsak; Aurpibul, Linda; Kosalaraksa, Pope; Kurniati, Nia; Prasitsuebsai, Wasana; Sophonphan, Jiratchaya; Ananworanich, Jintanat; Puthanakit, Thanyawee

    2016-04-24

    The impact of hypovitaminosis D and secondary hyperparathyroidism on bone mineral density (BMD) in the setting of pediatric HIV infection remains unclear. This study aimed to determine the prevalence of hypovitaminosis D and hyperparathyroidism and their effects on bone turnover and BMD among HIV-infected adolescents in Southeast Asia. A multicenter, cross-sectional study evaluating bone health and vitamin D metabolism in HIV-infected adolescents in Thailand and Indonesia. Perinatally HIV-infected adolescents aged 10-18 years on antiretroviral therapy with virologic suppression were enrolled. Serum 25-hydroxyvitamin D, intact parathyroid hormone, and bone turnover markers (C-terminal cross-linked telopeptide of type I collagen and procollagen type I amino-terminal propeptide) were assessed; serum 25-hydroxyvitamin D less than 20 ng/ml and intact parathyroid hormone more than 65 pg/ml were defined as hypovitaminosis D and hyperparathyroidism, respectively. Lumbar spine (L2-L4) BMD Z-score -2 or less was defined as low BMD. Of 394 adolescents, 57% were women. The median age [interquartile range (IQR)] was 15.0 (13.3-16.9) years. The prevalence of hypovitaminosis D, hyperparathyroidism, and both conditions were 21% [95% confidence interval (CI): 17-25%], 17% (95% CI: 13-20%), and 5% (95% CI: 3-7%), respectively. Adolescents with hypovitaminosis D and secondary hyperparathyroidism had the highest median bone resorption (C-terminal cross-linked telopeptide of type I collagen: 1610 vs. 1270 ng/l; P = 0.04) and bone formation (procollagen type I amino-terminal propeptide: 572 vs. 330 μg/l; P = 0.02) markers, and the greatest proportion of low BMD (42 vs. 15%; P = 0.01) compared with the rest of the cohort. Hypovitaminosis D complicated with secondary hyperparathyroidism was associated with increased bone turnover and bone loss. Early treatment of hypovitaminosis D before hyperparathyroidism occurs may be important to prevent bone mass deterioration.

  17. Effect of gamma irradiation sterilization on the osteoinductive capacity of demineralized bone powder

    International Nuclear Information System (INIS)

    Babak Arjmand; Hamid Reza Aghayan; Mehdi Golestani; Farid Azmoudeh Ardalan

    2008-01-01

    Full text: Gamma irradiation is a well known method for secondary sterilization of bone allograft before clinical use to reduce the risk of infections and complications. The current study evaluated the effect of gamma irradiation on the osteoinductive capability of human demineralized bone powder using a rat model. Twenty rats received two separate implants consisting of 30 mg aseptically-harvested and 30 mg gamma irradiated demineralized bone powder. The implants from each group were placed into two separate muscle pouch in the paravertebral muscles of each rat. All 20 rats were euthanized after 4 weeks and each implantation site was removed with 0.5 cm normal tissue around the implant. Histological examination was done to determine the presence or absence of new bone, cartilage and bone marrow element. All except one of 20 aseptically-harvested demineralized bone powder sites histologically contained new bone elements (95%) and six (30%) of 20 gamma irradiated demineralized bone powder sites showed evidence of new bone elements. There was significant difference between two groups (p<0.05). The results of this study indicate that gamma irradiation reduces osteoinductive properties of demineralized bone powder. But because of its availability and low cost it is widely used for secondary sterilization of bone allografts. (Author)

  18. Suppression Effect of Astaxanthin on Osteoclast Formation In Vitro and Bone Loss In Vivo

    Directory of Open Access Journals (Sweden)

    Yun-Ho Hwang

    2018-03-01

    Full Text Available Osteoporosis is characterized by a reduction of the bone mineral density (BMD and microarchitectural deterioration of the bone, which lead to bone fragility and susceptibility to fracture. Astaxanthin (AST has a variety of biological activities, such as a protective effect against asthma or neuroinflammation, antioxidant effect, and decrease of the osteoclast number in the right mandibles in the periodontitis model. Although treatment with AST is known to have an effect on inflammation, no studies on the effect of AST exposure on bone loss have been performed. Thus, in the present study, we examined the antiosteoporotic effect of AST on bone mass in ovariectomized (OVX mice and its possible mechanism of action. The administration of AST (5, 10 mg/kg for 6 weeks suppressed the enhancement of serum calcium, inorganic phosphorus, alkaline phosphatase, total cholesterol, and tartrate-resistant acid phosphatase (TRAP activity. The bone mineral density (BMD and bone microarchitecture of the trabecular bone in the tibia and femur were recovered by AST exposure. Moreover, in the in vitro experiment, we demonstrated that AST inhibits osteoclast formation through the expression of the nuclear factor of activated T cells (NFAT c1, dendritic cell-specific transmembrane protein (DC-STAMP, TRAP, and cathepsin K without any cytotoxic effects on bone marrow-derived macrophages (BMMs. Therefore, we suggest that AST may have therapeutic potential for the treatment of postmenopausal osteoporosis.

  19. The effect of 12-month participation in osteogenic and non-osteogenic sports on bone development in adolescent male athletes. The PRO-BONE study

    DEFF Research Database (Denmark)

    Vlachopoulos, Dimitris; Barker, Alan R; Ubago-Guisado, Esther

    2018-01-01

    OBJECTIVES: Research investigating the longitudinal effects of the most popular sports on bone development in adolescent males is scarce. The aim is to investigate the effect of 12-month participation in osteogenic and non-osteogenic sports on bone development. DESIGN: A 12-month study...... by dual-energy X-ray absorptiometry, and bone stiffness was measured by quantitative ultrasound. Bone outcomes at 12 months were adjusted for baseline bone status, age, height, lean mass and moderate to vigorous physical activity. RESULTS: Footballers had higher improvement in adjusted BMC at the total...... body, total hip, shaft, Ward's triangle, legs and bone stiffness compared to cyclists (6.3-8.0%). Footballers had significantly higher adjusted BMC at total body, shaft and legs compared to swimmers (5.4-5.6%). There was no significant difference between swimmers and cyclists for any bone outcomes...

  20. Late health effects of chronic radiation exposure of bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Yarmoshenko, Ilia V.; Malinovsky, Georgy P.; Konshina, Lidia G.; Zhukovsky, Michael V. [Institute of Industrial Ecology UB RAS, 620219, 20, Sophy Kovalevskoy St., Ekaterinburg (Russian Federation); Tuzankina, Irina A. [Institute of Immunology and Physiology UB RAS, 620049, 106, Pervomayskaya St., Ekaterinburg (Russian Federation)

    2014-07-01

    Accidental explosion of waste storage tank at former soviet plutonium production plant 'Mayak' in 1957 resulted in emission of considerable amount of radioactive substances to the atmosphere. Atmospheric transfer and fallout caused contamination of the environment by Sr-90 and short-lived radionuclides (East-Ural Radioactive Trace, EURT). Due to consumption of contaminated food and milk some internal organs were affected to relatively high radiation exposure. Archive data of causes of deaths of rural population of EURT northern part for period 1957-2000 were used to create the Register on causes of deaths. Register records related to the settlements where initial surface contamination by Sr-90 was above and below 3.7 kBq/m2 were included to exposed (4 844 records) and unexposed (6 158 records) group respectively. Basing on the Register the analysis of cancer and non-cancer health effects of radiation exposure was conducted. By estimating proportionate mortality ratios statistically significant excess mortality due to the groups of causes of death as follow was observed in exposed population: stomach, liver and cervix cancers; group consisted only of stomach cancer; non-cancer deceases of infectious etiology. Non-significant but remarkably high risk was observed for the following groups of causes of death: bone cancer; leukemia; liver cancer; cervix cancer. Insignificant, virtually zero risk was found for: non-gastrointestinal solid cancers; colon and lung cancers; non-infectious non-cancer deceases. At the same time, considerable radiation doses were absorbed in bone (mean bone surface dose about 0.1 Gy) and colon (mean dose about 0.07 Gy). Doses absorbed in other organs and tissues were negligible and amounted less than 0.01 Gy for most tissues. It can be seen that some disagreement between observed effects and absorbed doses is revealed. Most remarkable is the high excess risks of stomach, liver and cervix cancers as well as non-cancer deceases of

  1. Effect of hyperthyroidism and its treatment on bone mineral content

    International Nuclear Information System (INIS)

    Toh, S.H.; Claunch, B.C.; Brown, P.H.

    1985-01-01

    Patients with hyperthyroidism may develop osteopenia associated with fractures; however, there has been no general agreement on the incidence of osteopenia in hyperthyroidism or the recovery of the mineral loss after treatment of hyperthyroidism. The authors conducted a longitudinal prospective study on the effect of hyperthyroidism and its treatment on bone mineral content (BMC) using photon absorptiometry. They observed that both young and older hyperthyroid patients showed a significantly decreased baseline BMC compared with age- and sex-matched controls. They also observed a slight recovery of BMC in hyperthyroid patients at the two-year interval after a euthyroid state had been achieved. However, the BMC was still much lower than that of controls, and they did not find any significant restoration of BMC following ''cure'' of hyperthyroidism

  2. Effects of Recombinant Human Bone Morphogenetic Protein-2 on Vertical Bone Augmentation in a Canine Model.

    Science.gov (United States)

    Hsu, Yung-Ting; Al-Hezaimi, Khalid; Galindo-Moreno, Pablo; O'Valle, Francisco; Al-Rasheed, Abdulaziz; Wang, Hom-Lay

    2017-09-01

    Vertical bone augmentation (VBA) remains unpredictable and challenging for most clinicians. This study aims to compare hard tissue outcomes of VBA, with and without recombinant human bone morphogenetic protein (rhBMP)-2, under space-making titanium mesh in a canine model. Eleven male beagle dogs were used in the study. Experimental ridge defects were created to form atrophic ridges. VBA was performed via guided bone regeneration using titanium mesh and allografts. In experimental hemimandibles, rhBMP-2/absorbable collagen sponge was well mixed with allografts prior to procedures, whereas a control buffer was applied within controls. Dogs were euthanized after a 4-month healing period. Clinical and radiographic examinations were performed to assess ridge dimensional changes. In addition, specimens were used for microcomputed tomography (micro-CT) assessment and histologic analysis. Membrane exposure was found on five of 11 (45.5%) rhBMP-2-treated sites, whereas it was found on nine of 11 (81.8%) non-rhBMP-2-treated sites. Within 4 months of healing, rhBMP-2-treated sites showed better radiographic bone density, greater defect fill, and significantly more bone gain in ridge height (P 0.05). Under light microscope, predominant lamellar patterns were found in the specimen obtained from rhBMP-2 sites. With inherent limitations of the canine model and the concern of such a demanding surgical technique, current findings suggest that the presence of rhBMP-2 in a composite graft allows an increase of vertical gain, with formation of ectopic bone over the titanium mesh in comparison with non-rhBMP-2 sites.

  3. Identifying treatment effect heterogeneity in clinical trials using subpopulations of events: STEPP.

    Science.gov (United States)

    Lazar, Ann A; Bonetti, Marco; Cole, Bernard F; Yip, Wai-Ki; Gelber, Richard D

    2016-04-01

    Investigators conducting randomized clinical trials often explore treatment effect heterogeneity to assess whether treatment efficacy varies according to patient characteristics. Identifying heterogeneity is central to making informed personalized healthcare decisions. Treatment effect heterogeneity can be investigated using subpopulation treatment effect pattern plot (STEPP), a non-parametric graphical approach that constructs overlapping patient subpopulations with varying values of a characteristic. Procedures for statistical testing using subpopulation treatment effect pattern plot when the endpoint of interest is survival remain an area of active investigation. A STEPP analysis was used to explore patterns of absolute and relative treatment effects for varying levels of a breast cancer biomarker, Ki-67, in the phase III Breast International Group 1-98 randomized clinical trial, comparing letrozole to tamoxifen as adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer. Absolute treatment effects were measured by differences in 4-year cumulative incidence of breast cancer recurrence, while relative effects were measured by the subdistribution hazard ratio in the presence of competing risks using O-E (observed-minus-expected) methodology, an intuitive non-parametric method. While estimation of hazard ratio values based on O-E methodology has been shown, a similar development for the subdistribution hazard ratio has not. Furthermore, we observed that the subpopulation treatment effect pattern plot analysis may not produce results, even with 100 patients within each subpopulation. After further investigation through simulation studies, we observed inflation of the type I error rate of the traditional test statistic and sometimes singular variance-covariance matrix estimates that may lead to results not being produced. This is due to the lack of sufficient number of events within the subpopulations, which we refer to as instability of

  4. Effect of Microgravity on Bone Tissue and Calcium Metabolism

    Science.gov (United States)

    1997-01-01

    Session TA4 includes short reports concerning: (1) Human Bone Tissue Changes after Long-Term Space Flight: Phenomenology and Possible Mechanics; (2) Prediction of Femoral Neck Bone Mineral Density Change in Space; (3) Dietary Calcium in Space; (4) Calcium Metabolism During Extended-Duration Space Flight; (5) External Impact Loads on the Lower Extremity During Jumping in Simulated Microgravity and the Relationship to Internal Bone Strain; and (6) Bone Loss During Long Term Space Flight is Prevented by the Application of a Short Term Impulsive Mechanical Stimulus.

  5. Effect of capillary forces on immiscible two-phase flow in heterogeneous porous media

    Energy Technology Data Exchange (ETDEWEB)

    van Duijn, C.J.; Molenaar, J.; de Neef, M.J.

    1994-12-31

    We consider the one-dimensional two-phase flow including capillary effects through a heterogeneous porous medium. The heterogeneity is due to the spatial variation of the absolute permeability and the porosity. Both these quantities are assumed to be piecewise constant. At interfaces where the rock properties are discontinuous, we derive, by a regularization technique, conditions to match the values of the saturation on both sides. There are two conditions: a flux condition and an extended pressure condition. Applying these conditions we show that trapping of the wetting phase may occur near hetergeneities. To illustrate the behavior of the saturation we consider a time-dependent diffusion problem without convection, a stationary convection-diffusion problem, and the full time-dependent convection-diffusion problem (numerically). In particular the last two problems explicitly show the trapping behavior.

  6. Exact asymptotic relations for the effective response of linear viscoelastic heterogeneous media

    Science.gov (United States)

    Gallican, Valentin; Brenner, Renald; Suquet, Pierre

    2017-11-01

    This article addresses the asymptotic response of viscoelastic heterogeneous media in the frequency domain, at high and low frequencies, for different types of elementary linear viscoelastic constituents. By resorting to stationary principles for complex viscoelasticity and adopting a classification of the viscoelastic behaviours based on the nature of their asymptotic regimes, either elastic or viscous, four exact relations are obtained on the overall viscoelastic complex moduli in each case. Two relations are related to the asymptotic uncoupled heterogeneous problems, while the two remaining ones result from the viscoelastic coupling that manifests itself in the transient regime. These results also provide exact conditions on certain integrals in time of the effective relaxation spectrum. This general setting encompasses the results obtained in preceding studies on mixtures of Maxwell constituents [1,2]. xml:lang="fr"

  7. Reduced negativity effect in older adults' memory for emotional pictures: the heterogeneity-homogeneity list paradigm.

    Science.gov (United States)

    Grühn, Daniel; Scheibe, Susanne; Baltes, Paul B

    2007-09-01

    Using the heterogeneity-homogeneity list paradigm, the authors investigated 48 young adults' (20-30 years) and 48 older adults' (65-75 years) recognition memory for emotional pictures. The authors obtained no evidence for a positivity bias in older adults' memory: Age differences were primarily driven by older adults' diminished ability to remember negative pictures. The authors further found a strong effect of list types: Pictures, particularly neutral ones, were better recognized in homogeneous (blocked) lists than in heterogeneous (mixed) ones. Results confirm those of a previous study by D. Grühn, J. Smith, and P. B. Baltes (2005) that used a different type of to-be-remembered material, that is, pictures instead of words. (PsycINFO Database Record (c) 2007 APA, all rights reserved).

  8. The value of heterogeneity for cost-effectiveness subgroup analysis: conceptual framework and application.

    Science.gov (United States)

    Espinoza, Manuel A; Manca, Andrea; Claxton, Karl; Sculpher, Mark J

    2014-11-01

    This article develops a general framework to guide the use of subgroup cost-effectiveness analysis for decision making in a collectively funded health system. In doing so, it addresses 2 key policy questions, namely, the identification and selection of subgroups, while distinguishing 2 sources of potential value associated with heterogeneity. These are 1) the value of revealing the factors associated with heterogeneity in costs and outcomes using existing evidence (static value) and 2) the value of acquiring further subgroup-related evidence to resolve the uncertainty given the current understanding of heterogeneity (dynamic value). Consideration of these 2 sources of value can guide subgroup-specific treatment decisions and inform whether further research should be conducted to resolve uncertainty to explain variability in costs and outcomes. We apply the proposed methods to a cost-effectiveness analysis for the management of patients with acute coronary syndrome. This study presents the expected net benefits under current and perfect information when subgroups are defined based on the use and combination of 6 binary covariates. The results of the case study confirm the theoretical expectations. As more subgroups are considered, the marginal net benefit gains obtained under the current information show diminishing marginal returns, and the expected value of perfect information shows a decreasing trend. We present a suggested algorithm that synthesizes the results to guide policy. © The Author(s) 2014.

  9. Effects of surface roughness and electrokinetic heterogeneity on electroosmotic flow in microchannel

    Energy Technology Data Exchange (ETDEWEB)

    Masilamani, Kannan; Ganguly, Suvankar; Feichtinger, Christian; Bartuschat, Dominik; Rüde, Ulrich, E-mail: suva_112@yahoo.co.in [Department of Computer Science 10 University of Erlangen-Nuremberg, Cauerstr.11 91058 Erlangen (Germany)

    2015-06-15

    In this paper, a hybrid lattice-Boltzmann and finite-difference (LB-FD) model is applied to simulate the effects of three-dimensional surface roughness and electrokinetic heterogeneity on electroosmotic flow (EOF) in a microchannel. The lattice-Boltzmann (LB) method has been employed to obtain the flow field and a finite-difference (FD) method is used to solve the Poisson-Boltzmann (PB) equation for the electrostatic potential distribution. Numerical simulation of flow through a square cross-section microchannel with designed roughness is conducted and the results are critically analysed. The effects of surface heterogeneity on the electroosmotic transport are investigated for different roughness height, width, roughness interval spacing, and roughness surface potential. Numerical simulations reveal that the presence of surface roughness changes the nature of electroosmotic transport through the microchannel. It is found that the electroosmotic velocity decreases with the increase in roughness height and the velocity profile becomes asymmetric. For the same height of the roughness elements, the EOF velocity rises with the increase in roughness width. For the heterogeneously charged rough channel, the velocity profile shows a distinct deviation from the conventional plug-like flow pattern. The simulation results also indicate locally induced flow vortices which can be utilized to enhance the flow and mixing within the microchannel. The present study has important implications towards electrokinetic flow control in the microchannel, and can provide an efficient way to design a microfluidic system of practical interest. (paper)

  10. Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis

    Directory of Open Access Journals (Sweden)

    Vittorio Locatelli

    2014-01-01

    Full Text Available Background. Growth hormone (GH and insulin-like growth factor (IGF-1 are fundamental in skeletal growth during puberty and bone health throughout life. GH increases tissue formation by acting directly and indirectly on target cells; IGF-1 is a critical mediator of bone growth. Clinical studies reporting the use of GH and IGF-1 in osteoporosis and fracture healing are outlined. Methods. A Pubmed search revealed 39 clinical studies reporting the effects of GH and IGF-1 administration on bone metabolism in osteopenic and osteoporotic human subjects and on bone healing in operated patients with normal GH secretion. Eighteen clinical studies considered the effect with GH treatment, fourteen studies reported the clinical effects with IGF-1 administration, and seven related to the GH/IGF-1 effect on bone healing. Results. Both GH and IGF-1 administration significantly increased bone resorption and bone formation in the most studies. GH/IGF-1 administration in patients with hip or tibial fractures resulted in increased bone healing, rapid clinical improvements. Some conflicting results were evidenced. Conclusions. GH and IGF-1 therapy has a significant anabolic effect. GH administration for the treatment of osteoporosis and bone fractures may greatly improve clinical outcome. GH interacts with sex steroids in the anabolic process. GH resistance process is considered.

  11. Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis

    Science.gov (United States)

    Locatelli, Vittorio; Bianchi, Vittorio E.

    2014-01-01

    Background. Growth hormone (GH) and insulin-like growth factor (IGF-1) are fundamental in skeletal growth during puberty and bone health throughout life. GH increases tissue formation by acting directly and indirectly on target cells; IGF-1 is a critical mediator of bone growth. Clinical studies reporting the use of GH and IGF-1 in osteoporosis and fracture healing are outlined. Methods. A Pubmed search revealed 39 clinical studies reporting the effects of GH and IGF-1 administration on bone metabolism in osteopenic and osteoporotic human subjects and on bone healing in operated patients with normal GH secretion. Eighteen clinical studies considered the effect with GH treatment, fourteen studies reported the clinical effects with IGF-1 administration, and seven related to the GH/IGF-1 effect on bone healing. Results. Both GH and IGF-1 administration significantly increased bone resorption and bone formation in the most studies. GH/IGF-1 administration in patients with hip or tibial fractures resulted in increased bone healing, rapid clinical improvements. Some conflicting results were evidenced. Conclusions. GH and IGF-1 therapy has a significant anabolic effect. GH administration for the treatment of osteoporosis and bone fractures may greatly improve clinical outcome. GH interacts with sex steroids in the anabolic process. GH resistance process is considered. PMID:25147565

  12. Assessment of gene-by-sex interaction effect on bone mineral density

    DEFF Research Database (Denmark)

    Liu, Ching-Ti; Estrada, Karol; Yerges-Armstrong, Laura M

    2012-01-01

    Sexual dimorphism in various bone phenotypes, including bone mineral density (BMD), is widely observed; however, the extent to which genes explain these sex differences is unclear. To identify variants with different effects by sex, we examined gene-by-sex autosomal interactions genome-wide, and ......Sexual dimorphism in various bone phenotypes, including bone mineral density (BMD), is widely observed; however, the extent to which genes explain these sex differences is unclear. To identify variants with different effects by sex, we examined gene-by-sex autosomal interactions genome...

  13. Potential implications of the bystander effect on TCP and EUD when considering target volume dose heterogeneity.

    Science.gov (United States)

    Balderson, Michael J; Kirkby, Charles

    2015-01-01

    In light of in vitro evidence suggesting that radiation-induced bystander effects may enhance non-local cell killing, there is potential for impact on radiotherapy treatment planning paradigms such as the goal of delivering a uniform dose throughout the clinical target volume (CTV). This work applies a bystander effect model to calculate equivalent uniform dose (EUD) and tumor control probability (TCP) for external beam prostate treatment and compares the results with a more common model where local response is dictated exclusively by local absorbed dose. The broad assumptions applied in the bystander effect model are intended to place an upper limit on the extent of the results in a clinical context. EUD and TCP of a prostate cancer target volume under conditions of increasing dose heterogeneity were calculated using two models: One incorporating bystander effects derived from previously published in vitro bystander data ( McMahon et al. 2012 , 2013a); and one using a common linear-quadratic (LQ) response that relies exclusively on local absorbed dose. Dose through the CTV was modelled as a normal distribution, where the degree of heterogeneity was then dictated by changing the standard deviation (SD). Also, a representative clinical dose distribution was examined as cold (low dose) sub-volumes were systematically introduced. The bystander model suggests a moderate degree of dose heterogeneity throughout a target volume will yield as good or better outcome compared to a uniform dose in terms of EUD and TCP. For a typical intermediate risk prostate prescription of 78 Gy over 39 fractions maxima in EUD and TCP as a function of increasing SD occurred at SD ∼ 5 Gy. The plots only dropped below the uniform dose values for SD ∼ 10 Gy, almost 13% of the prescribed dose. Small, but potentially significant differences in the outcome metrics between the models were identified in the clinically-derived dose distribution as cold sub-volumes were introduced. In terms of

  14. Effect of latrogenic trauma on the bone scintigram: an animal study. Concise communication

    International Nuclear Information System (INIS)

    Alazraki, N.; Moitoza, J.; Heaphy, J.; Taylor, A. Jr.

    1984-01-01

    An animal study was performed to assess the effect on the Tc-99m phosphate bone scintigram of injury by needle aspiration or drill hole to metaphyseal and diaphyseal areas in immature and mature bones. Results showed that in 12 immature rabbits such trauma to metaphyseal regions had no effect on the bone image. Similar metaphyseal trauma in two mature dogs showed definite abnormalities on the bone image, but in one mature rabbit, no abnormality could be identified by scintigram. Diaphyseal trauma always gave a definitely abnormal bone image. Extrapolation of these results to humans should be cautious, but it suggests that needling or drilling in metaphyseal regions in neonates or young children probably does not affect later bone images

  15. Effects of a perfusion bioreactor activated novel bone substitute in spine fusion in sheep

    DEFF Research Database (Denmark)

    Sørensen, Jesper Roed; Koroma, Kariatta Ester; Ding, Ming

    2012-01-01

    To evaluate the effect of a large perfusion-bioreactor cell-activated bone substitute, on a two-level large posterolateral spine fusion sheep model.......To evaluate the effect of a large perfusion-bioreactor cell-activated bone substitute, on a two-level large posterolateral spine fusion sheep model....

  16. The Anabolic Effect of PTH on Bone is Attenuated by Simultaneous Glucocorticoid Treatment

    DEFF Research Database (Denmark)

    Oxlund, Hans; Ørtoft, Gitte; Thomsen, Jesper Skovhus

    2006-01-01

    . The pronounced anabolic effect of PTH injections on the endocortical and trabecular bone surfaces and less pronounced anabolic effect on periosteal surfaces were partially inhibited, but not prevented, by simultaneous GC treatment in old rats. Both cortical and cancellous bone possessed full mechanical...

  17. Effect of hormone replacement therapy on bone quality in early postmenopausal women

    DEFF Research Database (Denmark)

    Paschalis, E P; Boskey, A L; Kassem, M

    2003-01-01

    HRT is an effective prophylaxis against postmenopausal bone loss. Infrared imaging of paired iliac crest biopsies obtained at baseline and after 2 years of HRT therapy demonstrate an effect on the mineral crystallinity and collagen cross-links that may affect bone quality. Several studies have de...

  18. Effects of Alendronate and Raloxifene on Bone Density and Bone Turnover Markers in Postmenopausal Women

    Directory of Open Access Journals (Sweden)

    Ebru Zülfikaroğlu

    2011-04-01

    CONCLUSION: ALN 70 mg once- weekly significantly produced greater increases in spine and greater but not significantly increases in hip BMD and significantly greater reductions in markers of bone turnover than RLX in 1 yr treatment period. Both ALN and RLX treatment groups have similar safety and tolerability profiles.

  19. Local effect of zoledronic acid on new bone formation in posterolateral spinal fusion with demineralized bone matrix in a murine model.

    Science.gov (United States)

    Zwolak, Pawel; Farei-Campagna, Jan; Jentzsch, Thorsten; von Rechenberg, Brigitte; Werner, Clément M

    2018-01-01

    Posterolateral spinal fusion is a common orthopaedic surgery performed to treat degenerative and traumatic deformities of the spinal column. In posteriolateral spinal fusion, different osteoinductive demineralized bone matrix products have been previously investigated. We evaluated the effect of locally applied zoledronic acid in combination with commercially available demineralized bone matrix putty on new bone formation in posterolateral spinal fusion in a murine in vivo model. A posterolateral sacral spine fusion in murine model was used to evaluate the new bone formation. We used the sacral spine fusion model to model the clinical situation in which a bone graft or demineralized bone matrix is applied after dorsal instrumentation of the spine. In our study, group 1 received decortications only (n = 10), group 2 received decortication, and absorbable collagen sponge carrier, group 3 received decortication and absorbable collagen sponge carrier with zoledronic acid in dose 10 µg, group 4 received demineralized bone matrix putty (DBM putty) plus decortication (n = 10), and group 5 received DBM putty, decortication and locally applied zoledronic acid in dose 10 µg. Imaging was performed using MicroCT for new bone formation assessment. Also, murine spines were harvested for histopathological analysis 10 weeks after surgery. The surgery performed through midline posterior approach was reproducible. In group with decortication alone there was no new bone formation. Application of demineralized bone matrix putty alone produced new bone formation which bridged the S1-S4 laminae. Local application of zoledronic acid to demineralized bone matrix putty resulted in significant increase of new bone formation as compared to demineralized bone matrix putty group alone. A single local application of zoledronic acid with DBM putty during posterolateral fusion in sacral murine spine model increased significantly new bone formation in situ in our model. Therefore, our

  20. Poor bone health in underprivileged Indian girls: an effect of low bone mass accrual during puberty.

    Science.gov (United States)

    Khadilkar, Anuradha V; Sanwalka, Neha J; Kadam, Nidhi S; Chiplonkar, Shashi A; Khadilkar, Vaman V; Mughal, M Zulf

    2012-05-01

    A socio-economic gradient exists for most reasons of morbidity and mortality including delayed puberty in lower (LSES) as compared to higher (HSES) socio-economic stratum and puberty is an important factor affecting bone status in children and adolescents. Thus, a cross-sectional study was conducted on 195 age-matched pairs of girls (8-17years) from LSES and HSES in Pune City, India to assess the hypothesis that socio-economic factors working through late puberty would have a negative association with bone status of adolescents. Height, weight and Tanner stage were assessed. Total body bone mineral content (TBBMC), total body bone area (TBBA), total body bone mineral density (TBBMD), lean body mass (LBM) and total body fat mass (TBFM) were measured using GE Lunar DPX Pro Pencil Beam DXA (Wisconsin, USA) scanner. Mean TBBMC (1172±434g), TBBA (1351±356cm(2)), TBBMD (0.846±0.104g/cm(2)), LBM (21,622±5306g) and TBFM (7746±5194g) in LSES girls were significantly lower than that of HSES girls [TBBMC (1483±525g), TBBA (1533±380cm(2)), TBBMD (0.942±0.119g/cm(2)), LBM (24,308±5829g) and TBFM (12,196±7404g)] (pbone parameters. The differences in TBBMC, TBBA, LBM and TBFM between the 2 socio-economic strata at Tanner stage I were not significant (p>0.1) whereas there were significant differences in these parameters from Tanner stages II to V (pbone health in adolescent girls from the lower socio-economic stratum. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Male Hypogonadism and Osteoporosis: The Effects, Clinical Consequences, and Treatment of Testosterone Deficiency in Bone Health

    OpenAIRE

    Golds, Gary; Houdek, Devon; Arnason, Terra

    2017-01-01

    It is well recognized that bone loss accelerates in hypogonadal states, with female menopause being the classic example of sex hormones affecting the regulation of bone metabolism. Underrepresented is our knowledge of the clinical and metabolic consequences of overt male hypogonadism, as well as the more subtle age-related decline in testosterone on bone quality. While menopause and estrogen deficiency are well-known risk factors for osteoporosis in women, the effects of age-related testoster...

  2. A method to calculate the effect of heterogeneous composition on bundle power

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hang Bok [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-09-01

    In the DUPIC fuel cycle, the spent pressurized water reactor (PWR) fuel is used in a Canada deuterium uranium (CANDU) reactor. Depending on the initial condition and burnup history of PWR fuel, the DUPIC fuel composition varies accordingly. In order to see the effect of the fuel composition, a simple and fast method was developed and applied to the DUPIC fuel. This report discusses the method developed to predict the effect of heterogeneous fuel composition on the bundle power. (author). 3 refs., 5 tabs.

  3. The effects of transit time heterogeneity on brain oxygenation during rest and functional activation

    Science.gov (United States)

    Rasmussen, Peter M; Jespersen, Sune N; Østergaard, Leif

    2015-01-01

    The interpretation of regional blood flow and blood oxygenation changes during functional activation has evolved from the concept of ‘neurovascular coupling', and hence the regulation of arteriolar tone to meet metabolic demands. The efficacy of oxygen extraction was recently shown to depend on the heterogeneity of capillary flow patterns downstream. Existing compartment models of the relation between tissue metabolism, blood flow, and blood oxygenation, however, typically assume homogenous microvascular flow patterns. To take capillary flow heterogeneity into account, we modeled the effect of capillary transit time heterogeneity (CTH) on the ‘oxygen conductance' used in compartment models. We show that the incorporation of realistic reductions in CTH during functional hyperemia improves model fits to dynamic blood flow and oxygenation changes acquired during functional activation in a literature animal study. Our results support earlier observations that oxygen diffusion properties seemingly change during various physiologic stimuli, and posit that this phenomenon is related to parallel changes in capillary flow patterns. Furthermore, our results suggest that CTH must be taken into account when inferring brain metabolism from changes in blood flow- or blood oxygenation-based signals . PMID:25492112

  4. Estimating the effect of treatment rate changes when treatment benefits are heterogeneous: antibiotics and otitis media.

    Science.gov (United States)

    Park, Tae-Ryong; Brooks, John M; Chrischilles, Elizabeth A; Bergus, George

    2008-01-01

    Contrast methods to assess the health effects of a treatment rate change when treatment benefits are heterogeneous across patients. Antibiotic prescribing for children with otitis media (OM) in Iowa Medicaid is the empirical example. Instrumental variable (IV) and linear probability model (LPM) are used to estimate the effect of antibiotic treatments on cure probabilities for children with OM in Iowa Medicaid. Local area physician supply per capita is the instrument in the IV models. Estimates are contrasted in terms of their ability to make inferences for patients whose treatment choices may be affected by a change in population treatment rates. The instrument was positively related to the probability of being prescribed an antibiotic. LPM estimates showed a positive effect of antibiotics on OM patient cure probability while IV estimates showed no relationship between antibiotics and patient cure probability. Linear probability model estimation yields the average effects of the treatment on patients that were treated. IV estimation yields the average effects for patients whose treatment choices were affected by the instrument. As antibiotic treatment effects are heterogeneous across OM patients, our estimates from these approaches are aligned with clinical evidence and theory. The average estimate for treated patients (higher severity) from the LPM model is greater than estimates for patients whose treatment choices are affected by the instrument (lower severity) from the IV models. Based on our IV estimates it appears that lowering antibiotic use in OM patients in Iowa Medicaid did not result in lost cures.

  5. Blocking effect and numerical study of polymer particles dispersion flooding in heterogeneous reservoir

    Science.gov (United States)

    Zhu, Weiyao; Li, Jianhui; Lou, Yu

    2018-02-01

    Polymer flooding has become an effective way to improve the sweep efficiency in many oil fields. Many scholars have carried out a lot of researches on the mechanism of polymer flooding. In this paper, the effect of polymer on seepage is analyzed. The blocking effect of polymer particles was studied experimentally, and the residual resistance coefficient (RRF) were used to represent the blocking effect. We also build a mathematical model for heterogeneous concentration distribution of polymer particles. Furthermore, the effects of polymer particles on reservoir permeability, fluid viscosity and relative permeability are considered, and a two-phase flow model of oil and polymer particles is established. In addition, the model was tested in the heterogeneous stratum model, and three influencing factors, such as particle concentration, injection volume and PPD (short for polymer particle dispersion) injection time, were analyzed. Simulation results show that PPD can effectively improve sweep efficiency and especially improve oil recovery of low permeability layer. Oil recovery increases with the increase of particle concentration, but oil recovery increase rate gradually decreases with that. The greater the injected amount of PPD, the greater oil recovery and the smaller oil recovery increase rate. And there is an optimal timing to inject PPD for specific reservoir.

  6. Study of the heterogeneity effects of lung in the evaluation of absorbed dose in radiotherapy

    International Nuclear Information System (INIS)

    Campos, Luciana Tourinho

    2006-02-01

    The main objective of radiotherapy is to deliver the highest possible dose to the tumour, in order to destroy it, reducing as much as possible the doses to healthy tissues adjacent to the target volume. Therefore, it is necessary to do a planning of the treatment. The more complex is the treatment, the more difficult the planning will be, demanding computation sophisticated methods in its execution, in order to consider the heterogeneities present in the human body. Additionally, with the appearing of new radiotherapeutic techniques, that used irradiation fields of small area, for instance, the intensity modulated radiotherapy, the difficulties for the execution of a reliable treatment planning, became still larger. In this work it was studied the influence of the lung heterogeneity in the planning of the curves of percentage depth dose, PDP, obtained with the Eclipse R planning system for different sizes of irradiation fields, using the correction algorithms for heterogeneities available in the planning system: modified Batho, general Batho and equivalent tissue-air ratio. A thorax phantom, manufactured in acrylic, containing a region made of cork to simulate the lung tissue, was used. The PDP curves generated by the planning system were compared to those obtained by Monte Carlo simulation and with the use of thermoluminescent, TL, dosimetry. It was verified that the algorithms used by the Eclipse R system for the correction of heterogeneity effects are not able to generate correct results for PDP curves in the case of small fields, occurring differences of up to 100%, when the 1x1 cm 2 treatment field is considered. These differences can cause a considerable subdosage in the lung tissue, reducing the possibility of the patient cure. (author)

  7. Effect of ethylene oxide sterilization on the osteoinductivity of demineralized allograft bone powder

    International Nuclear Information System (INIS)

    Hamid Reza Aghayan; Babak Arjmand; Mehdi Golestani; Farokh Tirgari

    2008-01-01

    Full text: Ethylene oxide has been widely used for secondary sterilization of bone allograft to reduce the risk of infection and associated complications. In this study we investigate the effects of ethylene oxide gas sterilization on the osteoinductivity of demineralized bone Powder. Eighteen rats received two separate implants consisting of 30 mg aseptically prepared and 30 mg ethylene oxide-sterilized demineralized bone powder. The demineralized bone powder from each group was placed into two separate muscle pouch created in the paravertebral muscles of each rat. After 4 weeks each implantation site was removed with 0.5 cm normal tissue around the implant. Histological examination was done to determine the presence or absence of osteoinduction. All except one of eighteen aseptically prepared demineralized bone powder sites histologically contained new bone elements (94.4%) and fourteen (77.7%) of ethylene oxide sterilized demineralized bone powder sites showed evidence of new bone elements (p>0.05). There is no significant difference in osteoblast formation in two groups. We concluded that ethylene oxide sterilization in 42 degree C did not significantly reduce the osteoinductivity of demineralized bone powder. So ethylene oxide can be considered as a suitable but not perfect method for secondary sterilization of demineralized bone powder. (Author)

  8. Effect of bone-soft tissue friction on ultrasound axial shear strain elastography.

    Science.gov (United States)

    Tang, Songyuan; Chaudhry, Anuj; Kim, Namhee; Reddy, J N; Righetti, Raffaella

    2017-07-12

    Bone-soft tissue friction is an important factor affecting several musculoskeletal disorders, frictional syndromes and the ability of a bone fracture to heal. However, this parameter is difficult to determine using non-invasive imaging modalities, especially in clinical settings. Ultrasound axial shear strain elastography is a non-invasive imaging modality that has been used in the recent past to estimate the bonding between different tissue layers. As most elastography methods, axial shear strain elastography is primarily used in soft tissues. More recently, this technique has been proposed to assess the bone-soft tissue interface. In this paper, we investigate the effect of a variation in bone-soft tissue friction coefficient in the resulting axial shear strain elastograms. Finite element poroelastic models of bone specimens exhibiting different bone-soft tissue friction coefficients were created and mechanically analyzed. These models were then imported to an ultrasound elastography simulation module to assess the presence of axial shear strain patterns. In vitro experiments were performed to corroborate selected simulation results. The results of this study show that the normalized axial shear strain estimated at the bone-soft tissue interface is statistically correlated to the bone-soft tissue coefficient of friction. This information may prove useful to better interpret ultrasound elastography results obtained in bone-related applications and, possibly, monitor bone healing.

  9. Effects of Nrf2 Deficiency on Bone Microarchitecture in an Experimental Model of Osteoporosis

    Directory of Open Access Journals (Sweden)

    Lidia Ibáñez

    2014-01-01

    Full Text Available Objective. Redox imbalance contributes to bone fragility. We have evaluated the in vivo role of nuclear factor erythroid derived 2-related factor-2 (Nrf2, an important regulator of cellular responses to oxidative stress, in bone metabolism using a model of postmenopausal osteoporosis. Methods. Ovariectomy was performed in both wild-type and mice deficient in Nrf2 (Nrf2−/−. Bone microarchitecture was analyzed by μCT. Serum markers of bone metabolism were also measured. Reactive oxygen species production was determined using dihydrorhodamine 123. Results. Sham-operated or ovariectomized Nrf2−/− mice exhibit a loss in trabecular bone mineral density in femur, accompanied by a reduction in cortical area in vertebrae. Nrf2 deficiency tended to increase osteoblastic markers and significantly enhanced osteoclastic markers in sham-operated animals indicating an increased bone turnover with a main effect on bone resorption. We have also shown an increased production of oxidative stress in bone marrow-derived cells from sham-operated or ovariectomized Nrf2−/− mice and a higher responsiveness of bone marrow-derived cells to osteoclastogenic stimuli in vitro. Conclusion. We have demonstrated in vivo a key role of Nrf2 in the maintenance of bone microarchitecture.

  10. Engineering bone grafts with enhanced bone marrow and native scaffolds.

    Science.gov (United States)

    Hung, Ben P; Salter, Erin K; Temple, Josh; Mundinger, Gerhard S; Brown, Emile N; Brazio, Philip; Rodriguez, Eduardo D; Grayson, Warren L

    2013-01-01

    The translation of tissue engineering approaches to the clinic has been hampered by the inability to find suitable multipotent cell sources requiring minimal in vitro expansion. Enhanced bone marrow (eBM), which is obtained by reaming long bone medullary canals and isolating the solid marrow putty, has large quantities of stem cells and demonstrates significant potential to regenerate bone tissues. eBM, however, cannot impart immediate load-bearing mechanical integrity or maintain the gross anatomical structure to guide bone healing. Yet, its putty-like consistency creates a challenge for obtaining the uniform seeding necessary to effectively combine it with porous scaffolds. In this study, we examined the potential for combining eBM with mechanically strong, osteoinductive trabecular bone scaffolds for bone regeneration by creating channels into scaffolds for seeding the eBM. eBM was extracted from the femurs of adult Yorkshire pigs using a Synthes reamer-irrigator-aspirator device, analyzed histologically, and digested to extract cells and characterize their differentiation potential. To evaluate bone tissue formation, eBM was seeded into the channels in collagen-coated or noncoated scaffolds, cultured in osteogenic conditions for 4 weeks, harvested and assessed for tissue distribution and bone formation. Our data demonstrates that eBM is a heterogenous tissue containing multipotent cell populations. Furthermore, coating scaffolds with a collagen hydrogel significantly enhanced cellular migration, promoted uniform tissue development and increased bone mineral deposition. These findings suggest the potential for generating customized autologous bone grafts for treating critical-sized bone defects by combining a readily available eBM cell source with decellularized trabecular bone scaffolds. © 2013 S. Karger AG, Basel

  11. Effects of the 3D bone-to-implant contact and bone stiffness on the initial stability of a dental implant: micro-CT and resonance frequency analyses.

    Science.gov (United States)

    Hsu, J T; Huang, H L; Tsai, M T; Wu, A Y J; Tu, M G; Fuh, L J

    2013-02-01

    This study investigated the effects of bone stiffness (elastic modulus) and three-dimensional (3D) bone-to-implant contact ratio (BIC%) on the primary stabilities of dental implants using micro-computed tomography (micro-CT) and resonance frequency analyses. Artificial sawbone models with five values of elastic modulus (137, 123, 47.5, 22, and 12.4 MPa) comprising two types of trabecular structure (solid-rigid and cellular-rigid) were investigated for initial implant stability quotient (ISQ), measured using the wireless Osstell resonance frequency analyzer. Bone specimens were attached to 2 mm fibre-filled epoxy sheets mimicking the cortical shell. ISQ was measured after placing a dental implant into the bone specimen. Each bone specimen with an implant was subjected to micro-CT scanning to calculate the 3D BIC% values. The similarity of the cellular type of artificial bone to the trabecular structure might make it more appropriate for obtaining accurate values of primary implant stability than solid-bone blocks. For the cellular-rigid bone models, the ISQ increased with the elastic modulus of cancellous bone. The regression correlation coefficient was 0.96 for correlations of the ISQ with the elasticity of cancellous bone and with the 3D BIC%. The initial implant stability was moderately positively correlated with the elasticity of cancellous bone and with the 3D BIC%. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. A novel use of 3D printing model demonstrates the effects of deteriorated trabecular bone structure on bone stiffness and strength.

    Science.gov (United States)

    Barak, Meir Max; Black, Margaret Arielle

    2018-02-01

    Trabecular bone structure is crucial to normal mechanical behavior of bones. Studies have shown that osteoporosis negatively affects trabecular bone structure, mainly by reducing bone volume fraction (BV/TV) and thus increasing fracture risk. One major limitation in assessing and quantifying the effect of this structural deterioration is that no two trabecular structures are identical. Thus, when we compare a group of healthy bones against a different group of bones that experienced resorption (i.e. decreased BV/TV) we only discover an "average" mechanical effect. It is impossible to quantify the mechanical effect of individual structural deterioration for each sample, simply because we never have the same sample in both states (intact and deteriorated structure). 3D printing is a new technology that can assist in overcoming this issue. Here we report a preliminary study that compares a healthy 3D printed trabecular bone model with the same model after bone resorption was simulated. Since the deteriorated structural bone model is derived from the healthy one, it is possible to directly estimate (percentage wise) the decrease of tissue stiffness and strength as a result of bone resorption for this specific structure. Our results demonstrate that a relatively small decrease in BV/TV (about 8%) leads to a dramatic decrease in structural strength (24%) and structural stiffness (17%), (P printing is a novel and valuable tool for quantifying the effect of structural deterioration on the mechanical properties of trabecular bone. In the future, this approach may help us attain better personal fracture risk assessments by CT scanning, 3D printing and mechanically testing individual bone replicas from patients suffering excessive bone resorption. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Comparative radioprotective studies of chlorpromazine and cysteamine on rat bone development; Effect on serum and bone proteins

    Energy Technology Data Exchange (ETDEWEB)

    Abdeen, A M; Ibrahim, H A; Badawy, M; Elkholy, W M.E.

    1986-01-01

    Experiments were planned to study the radioprotective effect of chlorpromazine (CPZ) and Cysteamine (Cys), when injected separately or combined before irradiation, on some factors affecting the development of rat bone. The results obtained can be summarized as follows: (1) The body weight decreased due to gamma-irradiation. (2) The mortality rate increased after irradiation, but diminished by single or double chemical injection before irradiation. (3) The serum total protein; albumin, globulin contents and A/G ratio were significantly increased, 6 hrs. After irradiation, then declined afterwards. (4) Histochemically, a decrease in bone protein content was demonstrates after irradiation. The above irradiation effects were suppressed by injection of the radioprotective substances. Their effect seems to be cumulative. 4 fig.,3 tab.

  14. Developing effective automated feedback in temporal bone surgery simulation.

    Science.gov (United States)

    Wijewickrema, Sudanthi; Piromchai, Patorn; Zhou, Yun; Ioannou, Ioanna; Bailey, James; Kennedy, Gregor; O'Leary, Stephen

    2015-06-01

    We aim to test the effectiveness, accuracy, and usefulness of an automated feedback system in facilitating skill acquisition in virtual reality surgery. We evaluate the performance of the feedback system through a randomized controlled trial of 24 students allocated to feedback and nonfeedback groups. The feedback system was based on the Melbourne University temporal bone surgery simulator. The study was conducted at the simulation laboratory of the Royal Victorian Eye and Ear Hospital, Melbourne. The study participants were medical students from the University of Melbourne, who were asked to perform virtual cortical mastoidectomy on the simulator. The extent to which the drilling behavior of the feedback and nonfeedback groups differed was used to evaluate the effectiveness of the system. Its accuracy was determined through a postexperiment observational assessment of recordings made during the experiment by an expert surgeon. Its usability was evaluated using students' self-reports of their impressions of the system. A Friedman's test showed that there was a significant improvement in the drilling performance of the feedback group, χ(2)(1) = 14.450, P feedback (when trainee behavior was detected) 88.6% of the time and appropriate feedback (accurate advice) 84.2% of the time. Participants' opinions about the usefulness of the system were highly positive. The automated feedback system was observed to be effective in improving surgical technique, and the provided feedback was found to be accurate and useful. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  15. Effects of Curcumin on Bone Loss and Biochemical Markers of Bone Turnover in Patients with Spinal Cord Injury.

    Science.gov (United States)

    Hatefi, Masoud; Ahmadi, Mohammad Reza Hafezi; Rahmani, Asghar; Dastjerdi, Masoud Moghadas; Asadollahi, Khairollah

    2018-06-01

    Osteoporosis is one of the most common problems of patients with spinal cord injuries (SCIs). The current study aimed to evaluate the antiosteoporotic effects of curcumin on densitometry parameters and biomarkers of bone turnovers among patients with SCI. The current controlled clinical trial was conducted among 100 patients with SCI referred to an outpatient clinic of rehabilitation in Ilam City, Iran, in 2013-2015. The intervention group received 110/mg/kg/day curcumin for 6 months and the control group received placebo. Bone mineral density (BMD) was measured in all patients. The level of procollagen type I N-terminal propeptide, serum carboxy-terminal telopeptide of type I collagen, osteocalcin, and bone-specific alkaline phosphates were compared before and after study. BMD indicators of lumbar, femoral neck, and total hip in the control group significantly decreased compared with the beginning of study. However, in the curcumin group, a significant increase was observed in BMD indicators of lumbar, femoral neck, and hip at the end of study compared with the beginning. There was also a significant difference between interventional and control groups for the mean BMD of femoral neck and hip at the end of study (0.718 ± 0.002 g/cm 2 vs. 0.712 ± 0.003 g/cm 2 and 0.742 ± 0.031 g/cm 2 vs. 0.692 ± 0.016 g/cm 2 , respectively). Curcumin, via modulation of densitometry indices and bone resorption markers, showed inhibitory effects on the process of osteoporosis. Treatment with curcumin was significantly associated with a decrease in the osteoporosis progression and bone turnover markers of patients with SCI after 6 months. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Effects of short-term testosterone replacement on areal bone mineral density and bone turnover in young hypogonadal males

    Directory of Open Access Journals (Sweden)

    Prasun Deb

    2012-01-01

    Full Text Available Context: Effect of parenteral testosterone esters administration on bone-mineral density (BMD and bone turnover in young age onset male hypogonadism is not studied in Indian subjects. Aims: To prospectively study the effect of short-term (6 months replacement therapy with parenteral testosterone enanthate-propionate combination on BMD and bone turnover markers in hypogonadal adult patients. Settings and Design: Prospective, tertiary care academic center. Materials and Methods: Thirteen young, otherwise healthy hypogonadal males (age 25.5 ± 4.9 yrs, serum testosterone 2.56 ± 4.29 nmol/l were subjected to BMD measurements (DXA and estimation of urinary Crosslaps™ and serum osteocalcin at baseline. Twelve healthy age and BMI-matched males served as controls for BMD measurements. The hypogonadal patients were administered parenteral testosterone esters (as mixed enanthate and propionate 250 mg i.m. every 2-3 weeks, and prospectively followed for 6 months. BMD and bone markers were studied at the end of 6 months. Statistical Analysis Used: Mann-Whitney nonparametric test, paired t-test and Pearson′s test of two-tail significance. Results: At baseline, BMD was significantly lower in hypogonadal males as compared to that in controls. With testosterone replacement, there was significant improvement in BMD, both at trabecular and cortical sites, There was a decline in bone turnover with treatment (Ur Crosslaps™:creatinine ratio: pretreatment 72.8 ± 40.4, post-treatment 35.5 ± 23.8 μg/mmol, P = 0.098; serum osteocalcin: pre-treatment 41.0 ± 16.8, post-treatment 31.7 ± 2.1 ng/ml, P = 0.393. Conclusions: Short-term parenteral testosterone replacement significantly improves BMD at the hip, lumbar spine and forearm in hypogonadal young males.

  17. Metabolic Syndrome and Bone: Pharmacologically Induced Diabetes has Deleterious Effect on Bone in Growing Obese Rats.

    Science.gov (United States)

    Bagi, Cedo M; Edwards, Kristin; Berryman, Edwin

    2017-12-01

    Metabolic syndrome and osteoporosis share similar risk factors. Also, patients with diabetes have a higher risk of osteoporosis and fracture. Liver manifestations, such as non-alcoholic steatohepatitis (NASH), of metabolic syndrome are further aggravated in diabetics and often lead to liver failure. Our objective was to create a rat model of human metabolic syndrome and determine the long-term impact of early-onset T1D on bone structure and strength in obese growing rats. Male rats were given either standard chow and RO water (Controls) or a high-fat, high-cholesterol diet and sugar water containing 55% fructose and 45% glucose (HFD). A third group of rats received the HFD diet and a single dose of streptozotocin to induce type 1 diabetes (HFD/Sz). Body weight and glucose tolerance tests were conducted several times during the course of the study. Serum chemistry, liver enzymes, and biomarkers of bone metabolism were evaluated at 10 and 28 weeks. Shear wave elastography and histology were used to assess liver fibrosis. Cancellous bone structure and cortical bone geometry were evaluated by mCT and strength by the 3-point bending method. Body mass and fat accumulation was significantly higher in HFD and HFD/Sz rats compared to Controls. Rats in both the HFD and HFD/Sz groups developed NASH, although the change was more severe in diabetic rats. Although both groups of obese rats had larger bones, their cancellous structure and cortical thickness were reduced, resulting in diminished strength that was further aggravated by diabetes. The HFD and HFD/Sz rats recapitulate MeSy in humans with liver pathology consistent with NASH. Our data provide strong indication that obesity accompanied by type 1 diabetes significantly aggravates comorbidities of MeSy, including the development of osteopenia and weaker bones. The juvenile rat skeleton seems to be more vulnerable to damage imposed by obesity and diabetes and may offer a model to inform the underlying pathology associated

  18. The effect of polyunsaturated fatty acids and vitamin D on growth and bone mineralization in children

    DEFF Research Database (Denmark)

    Pedersen, Louise

    2012-01-01

    Polyunsaturated fatty acids (PUFA) and vitamin D are important for fat and bone metabolism but the intake is declining in Western societies with a potential deleterious effect on growth and bone health. Dietary PUFA composition favors the intake of omega-6 (n-6 PUFA) compared to omega-3 (n-3 PUFA...... early in life is essential for preventive steps against development of overweight and obesity. Vitamin D promotes bone mineralization and growth through regulation of the calcium homeostasis, and via activation of vitamin D receptors on bone and cartilage forming cells. However vitamin D insufficiency...... development, and fat percentage; serum vitamin D status in cord blood and height development and bone mineralization; and serum vitamin D status at 4 years and bone mineralization. This is performed in the Copenhagen Prospective Study of Asthma in Childhood (COPSAC2000). In Study 1, breast-milk n-3 PUFA...

  19. Alendronate Can Improve Bone Alterations in Experimental Diabetes by Preventing Antiosteogenic, Antichondrogenic, and Proadipocytic Effects of AGEs on Bone Marrow Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Sara Rocío Chuguransky

    2016-01-01

    Full Text Available Bisphosphonates such as alendronate are antiosteoporotic drugs that inhibit the activity of bone-resorbing osteoclasts and secondarily promote osteoblastic function. Diabetes increases bone-matrix-associated advanced glycation end products (AGEs that impair bone marrow progenitor cell (BMPC osteogenic potential and decrease bone quality. Here we investigated the in vitro effect of alendronate and/or AGEs on the osteoblastogenic, adipogenic, and chondrogenic potential of BMPC isolated from nondiabetic untreated rats. We also evaluated the in vivo effect of alendronate (administered orally to rats with insulin-deficient Diabetes on long-bone microarchitecture and BMPC multilineage potential. In vitro, the osteogenesis (Runx2, alkaline phosphatase, type 1 collagen, and mineralization and chondrogenesis (glycosaminoglycan production of BMPC were both decreased by AGEs, while coincubation with alendronate prevented these effects. The adipogenesis of BMPC (PPARγ, intracellular triglycerides, and lipase was increased by AGEs, and this was prevented by coincubation with alendronate. In vivo, experimental Diabetes (a decreased femoral trabecular bone area, osteocyte density, and osteoclastic TRAP activity; (b increased bone marrow adiposity; and (c deregulated BMPC phenotypic potential (increasing adipogenesis and decreasing osteogenesis and chondrogenesis. Orally administered alendronate prevented all these Diabetes-induced effects on bone. Thus, alendronate could improve bone alterations in diabetic rats by preventing the antiosteogenic, antichondrogenic, and proadipocytic effects of AGEs on BMPC.

  20. Bone mineral measurement, experiment M078. [space flight effects on human bone composition

    Science.gov (United States)

    Rambaut, P. C.; Vogel, J. M.; Ullmann, J.; Brown, S.; Kolb, F., III

    1973-01-01

    Measurement tests revealed few deviations from baseline bone mineral measurements after 56 days in a Skylab-type environment. No mineral change was observed in the right radius. One individual, however, showed a possible mineral loss in the left os calcis and another gained mineral in the right ulna. The cause of the gain is unclear but may be attributable to the heavy exercise routines engaged in by the crewmember in question. Equipment problems were identified during the experiment and rectified.

  1. Accounting for Heterogeneity in Relative Treatment Effects for Use in Cost-Effectiveness Models and Value-of-Information Analyses.

    Science.gov (United States)

    Welton, Nicky J; Soares, Marta O; Palmer, Stephen; Ades, Anthony E; Harrison, David; Shankar-Hari, Manu; Rowan, Kathy M

    2015-07-01

    Cost-effectiveness analysis (CEA) models are routinely used to inform health care policy. Key model inputs include relative effectiveness of competing treatments, typically informed by meta-analysis. Heterogeneity is ubiquitous in meta-analysis, and random effects models are usually used when there is variability in effects across studies. In the absence of observed treatment effect modifiers, various summaries from the random effects distribution (random effects mean, predictive distribution, random effects distribution, or study-specific estimate [shrunken or independent of other studies]) can be used depending on the relationship between the setting for the decision (population characteristics, treatment definitions, and other contextual factors) and the included studies. If covariates have been measured that could potentially explain the heterogeneity, then these can be included in a meta-regression model. We describe how covariates can be included in a network meta-analysis model and how the output from such an analysis can be used in a CEA model. We outline a model selection procedure to help choose between competing models and stress the importance of clinical input. We illustrate the approach with a health technology assessment of intravenous immunoglobulin for the management of adult patients with severe sepsis in an intensive care setting, which exemplifies how risk of bias information can be incorporated into CEA models. We show that the results of the CEA and value-of-information analyses are sensitive to the model and highlight the importance of sensitivity analyses when conducting CEA in the presence of heterogeneity. The methods presented extend naturally to heterogeneity in other model inputs, such as baseline risk. © The Author(s) 2015.

  2. Effects of long-term estrogen replacement therapy on bone turnover in periarticular tibial osteophytes in surgically postmenopausal cynomolgus monkeys

    OpenAIRE

    Olson, Erik J.; Lindgren, Bruce R.; Carlson, Cathy S.

    2007-01-01

    The aims of the present study were to assess the effects of long-term estrogen replacement therapy (ERT) on size and indices of bone turnover in periarticular osteophytes in ovariectomized cynomolgus monkeys and to compare dynamic indices of bone turnover in osteophyte bone with those of subchondral bone (SCB) and epiphyseal/metaphyseal cancellous (EMC) bone. One hundred sixty-five adult female cynomolgus macaques were bilaterally ovariectomized and randomly divided into three age- and weight...

  3. Efficiency effects of observed and unobserved heterogeneity: Evidence from Norwegian electricity distribution networks

    International Nuclear Information System (INIS)

    Growitsch, Christian; Jamasb, Tooraj; Wetzel, Heike

    2012-01-01

    Since the 1990s, efficiency and benchmarking analysis has increasingly been used in network utilities research and regulation. A recurrent concern is the effect of observable environmental factors that are beyond the influence of firms and unobserved factors that are not identifiable on measured cost and quality performance of firms. This paper analyses the effect of observed geographic and weather factors and unobserved heterogeneity on a set of 128 Norwegian electricity distribution utilities for the 2001–2004 period. We utilise data on 78 geographic and weather variables to identify real economic inefficiency while controlling for observed and unobserved heterogeneity. We use the Factor Analysis technique to reduce the number of environmental factors into few composite variables and to avoid the problem of multicollinearity. In order to identify firm-specific inefficiency, we then estimate a pooled version of the established stochastic frontier model of Aigner et al. (1977) and the recent true random effects model of Greene (2004; 2005a,b) without and with environmental variables. The results indicate that the observed environmental factors have a rather limited influence on the utilities' average efficiency and the efficiency rankings. Moreover, the difference between the average efficiency scores and the efficiency rankings among the pooled and the true random effects models imply that the type of SFA model used is highly influencing the efficiency estimates.

  4. Effects of Bone Morphogenic Proteins on Engineered Cartilage

    Science.gov (United States)

    Gooch, Keith, J.; Blunk, Torsten; Courter, Donald L.; Sieminski, Alisha; Vunjak-Novakovic, Gordana; Freed, Lisa E.

    2007-01-01

    A report describes experiments on the effects of bone morphogenic proteins (BMPs) on engineered cartilage grown in vitro. In the experiments, bovine calf articular chondrocytes were seeded onto biodegradable polyglycolic acid scaffolds and cultured in, variously, a control medium or a medium supplemented with BMP-2, BMP-12, or BMP-13 in various concentrations. Under all conditions investigated, cell-polymer constructs cultivated for 4 weeks macroscopically and histologically resembled native cartilage. At a concentration of 100 ng/mL, BMP-2, BMP-12, or BMP-13 caused (1) total masses of the constructs to exceed those of the controls by 121, 80, or 62 percent, respectively; (2) weight percentages of glycosaminoglycans in the constructs to increase by 27, 18, or 15, respectively; and (3) total collagen contents of the constructs to decrease to 63, 89, or 83 percent of the control values, respectively. BMP-2, but not BMP-12 or BMP-13, promoted chondrocyte hypertrophy. These observations were interpreted as suggesting that the three BMPs increase the growth rates and modulate the compositions of engineered cartilage. It was also concluded that in vitro engineered cartilage is a suitable system for studying effects of BMPs on chondrogenesis in a well-defined environment.

  5. Effects of farm heterogeneity and methods for upscaling on modelled nitrogen losses in agricultural landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, T., E-mail: tommy.dalgaard@agrsci.dk [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Hutchings, N. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Dragosits, U. [CEH Edinburgh, Bush Estate, Penicuik, Midlothian EH26 0QB, Scotland (United Kingdom); Olesen, J.E.; Kjeldsen, C. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Drouet, J.L.; Cellier, P. [INRA, UMR Environnement et Grandes Cultures, BP 01, 78850 Thiverval-Grignon (France)

    2011-11-15

    The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20-30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions. - Highlights: > Farm-N balances and the distribution on types of N-losses are modelled for 56 farms. > Farm type significantly affects N-losses and soil-N accumulation. > A non-linear relation between livestock density and ammonia loss is identified. > Approaches for upscaling from farm to landscape level are discussed. > Accounting farm heterogeneity is important when upscaling N-losses. - This study illustrates the importance of including non-linear effects of farm and landscape heterogeneity on the modelling and upscaling of farm nitrogen losses and greenhouse gas emissions in agricultural landscapes.

  6. Effects of farm heterogeneity and methods for upscaling on modelled nitrogen losses in agricultural landscapes

    International Nuclear Information System (INIS)

    Dalgaard, T.; Hutchings, N.; Dragosits, U.; Olesen, J.E.; Kjeldsen, C.; Drouet, J.L.; Cellier, P.

    2011-01-01

    The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20-30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions. - Highlights: → Farm-N balances and the distribution on types of N-losses are modelled for 56 farms. → Farm type significantly affects N-losses and soil-N accumulation. → A non-linear relation between livestock density and ammonia loss is identified. → Approaches for upscaling from farm to landscape level are discussed. → Accounting farm heterogeneity is important when upscaling N-losses. - This study illustrates the importance of including non-linear effects of farm and landscape heterogeneity on the modelling and upscaling of farm nitrogen losses and greenhouse gas emissions in agricultural landscapes.

  7. Effect of water on piezoelectricity in bone and collagen.

    Science.gov (United States)

    Netto, T G; Zimmerman, R L

    1975-01-01

    Interferometric measurements of bovine bone and tendon show that the values of the piezoelectric strain constant d14 decrease with hydration from the dry values of 0.2 X 10(-14) and 2.0 X 10(-14) m/V, respectively. The decrease of piezoelectricity in tendon is exponential with a characteristic hydration of 7% by weight from which an upper limit of the average molecular weight of the responsible electric dipole moments is deduced. The piezoelectricity in bone decreases relatively slowly with hydration indicating that the electric dipoles in bone collagen are subject to a different cancelling mechanism. PMID:1148359

  8. Effect of sex hormones on bone density during growth

    International Nuclear Information System (INIS)

    Gilsanz, V.; Roe, T.F.; Wells, T.R.; Senac, M.O. Jr.; Landing, B.; Libaneti, C.; Cann, C.E.; Schulz, E.

    1986-01-01

    The development of special phantoms permitted precise measurement of vertebral mineral content by CT in the very young. The normal standards for spinal trabecular bone of children aged 0-18 years are presented. Although there is no age-related difference in bone density before puberty, there is a significant increase in bone mineral content after puberty. The increase in sex hormones during puberty accounts for the increased density. Longitudinal studies analyzing vertebral density changes in castrated rabbits after testosterone and estradiol administration are discussed

  9. Effect of freezing rate and storage time on shelf-life quality of hot boned and conventionally boned ground beef

    International Nuclear Information System (INIS)

    Gapud, V.G.; Schlimme, D.V.

    1986-01-01

    Commercially processed, 80% lean, chub packaged ground beef (both conventionally boned and hot boned) was frozen to O F (-18 0 C) at three rates: 72, 96, and 120 hours before storage at O F (-18 0 C). The meat was examined after 0, 1.5, 3, 6, 9, and 12 months storage for the following attributes: psychrophile and aerobic plate counts, free fatty acid (FFA) and thiobarbituric acid (TBA) values, niacin content, raw and cooked color, moisture, fat and protein contents, and cook shrink and texture of cooked patties. Freezing rates had no significant effect on microbial load, niacin content, color, or cook shrink and texture. Freezing rate had a significant effect upon TBA and FFA values. Niacin, cook shrink and moisture values declined and TBA and FFA values increased with storage. Raw meat Hunter L value increased and Hunter a/b value declined during storage. Substantial quality differences between meat types were found

  10. Effect of Tissue Heterogeneity on the Transmembrane Potential of Type-1 Spiral Ganglion Neurons: A Simulation Study.

    Science.gov (United States)

    Sriperumbudur, Kiran Kumar; Pau, Hans Wilhelm; van Rienen, Ursula

    2018-03-01

    Electric stimulation of the auditory nerve by cochlear implants has been a successful clinical intervention to treat the sensory neural deafness. In this pathological condition of the cochlea, type-1 spiral ganglion neurons in Rosenthal's canal play a vital role in the action potential initiation. Various morphological studies of the human temporal bones suggest that the spiral ganglion neurons are surrounded by heterogeneous structures formed by a variety of cells and tissues. However, the existing simulation models have not considered the tissue heterogeneity in the Rosenthal's canal while studying the electric field interaction with spiral ganglion neurons. Unlike the existing models, we have implemented the tissue heterogeneity in the Rosenthal's canal using a computationally inexpensive image based method in a two-dimensional finite element model. Our simulation results suggest that the spatial heterogeneity of surrounding tissues influences the electric field distribution in the Rosenthal's canal, and thereby alters the transmembrane potential of the spiral ganglion neurons. In addition to the academic interest, these results are especially useful to understand how the latest tissue regeneration methods such as gene therapy and drug-induced resprouting of peripheral axons, which probably modify the density of the tissues in the Rosenthal's canal, affect the cochlear implant functionality.

  11. Effect of Teriparatide, Vibration and the Combination on Bone Mass and Bone Architecture in Chronic Spinal Cord Injury

    Science.gov (United States)

    2015-12-01

    osteoporosis. J Bone Miner Res, 2003. 18(3): p. 539-43. 10. Ma, Y., et al., Parathyroid hormone and mechanical usage have a synergistic effect in rat tibial...directions, respectively. Material nonlinearity was modeled as bilinear elastic– plastic with a postyield modulus that was 5% of the pre-yield modulus(31...Injury Poster Sessions, Presentation Number: SA0435 Session: Poster Session I & Poster Tours Saturday, October 5, 2013 12:00 PM - 2:00 PM, Baltimore

  12. Effect of dietary soy isoflavones on bone loss in ovariectomized rats

    African Journals Online (AJOL)

    Abstract. Purpose: To determine the effect of dietary soy isoflavone supplementation on bone loss in ... Keywords: Mineral elements, Alkaline phosphatase, Isoflavones, Bone loss, Notch pathway. This is an Open .... incubated for 3 h in 5% non-fat-milk blocking solution at ..... protect against osteopenia in ovariectomised rats.

  13. P38 MAPK / beta-catenin canonical wnt signaling mediated bone formation effects of blueberries

    Science.gov (United States)

    Appropriate nutrition is one of the critical factors that influences bone development. We studied the effects of dietary blueberry supplementation on bone growth in weanling rats. Weanling male and female rats were fed AIN-93G semi-purified diets supplemented with 10% whole blueberry powder for 14 a...

  14. Wnt/RANKL-mediated bone growth promoting effects of blueberries in weanling rats

    Science.gov (United States)

    We studied the effects of dietary blueberry supplementation on bone growth in weanling rats. Weanling male and female rats were fed AIN-93G semi-purified diets supplemented with 10% whole blueberry powder for 14 and 30 days beginning on PND 21. In both sexes tibial bone mineral density and content a...

  15. Effect of dietary soy isoflavones on bone loss in ovariectomized rats ...

    African Journals Online (AJOL)

    Purpose: To determine the effect of dietary soy isoflavone supplementation on bone loss in ovariectomized (OVX) rats. Methods: Forty-eight rats were assigned randomly to groups of OVX rats receiving soy isoflavones (20, 30, or 40 mg/kg of body weight daily), untreated OVX rats, or untreated intact rats. After 8 weeks, bone ...

  16. The effect of storage on the nutritional quality of meat and bone meal

    NARCIS (Netherlands)

    Hendriks, W.H.; Cottam, Y.H.; Thomas, D.V.

    2006-01-01

    The effect of storage on the nutritional quality of meat and bone meal was investigated. Three meat and bone meal samples were stored for 1, 2, 3, 6 and 9 months, with or without the addition of the antioxidants (butylatedhydroxytoluene and butylatedhydroxyanisole). Gross composition, thiobarbituric

  17. Optimizing tamoxifen-inducible Cre/loxp system to reduce tamoxifen effect on bone turnover in long bones of young mice.

    Science.gov (United States)

    Zhong, Zhendong A; Sun, Weihua; Chen, Haiyan; Zhang, Hongliang; Lay, Yu-An E; Lane, Nancy E; Yao, Wei

    2015-12-01

    For tamoxifen-dependent Cre recombinase, also known as CreER recombinase, tamoxifen (TAM) is used to activate the Cre to generate time- and tissue-specific mouse mutants. TAM is a potent CreER system inducer; however, TAM is also an active selective estrogen receptor modulator (SERM) that can influence bone homeostasis. The purpose of this study was to optimize the TAM dose for Cre recombinase activation while minimizing the effects of TAM on bone turnover in young growing mice. To evaluate the effects of TAM on bone turnover and bone mass, 1-month-old wild-type male and female mice were intraperitoneally injected with TAM at 0, 1, 10 or 100mg/kg/day for four consecutive days, or 100, 300 mg/kg/day for one day. The distal femurs were analyzed one month after the last TAM injection by microCT, mechanical test, and surface-based bone histomorphometry. Similar doses of TAM were used in Col1 (2.3 kb)-CreERT2; mT/mG reporter male mice to evaluate the dose-dependent efficacy of Cre-ER activation in bone tissue. A TAM dose of 100 mg/kg × 4 days significantly increased trabecular bone volume/total volume (BV/TV) of the distal femur, femur length, bone strength, and serum bone turnover markers compared to the 0mg control group. In contrast, TAM doses ≤ 10 mg/kg did not significantly change any of these parameters compared to the 0mg group, although a higher bone strength was observed in the 10mg group. Surface-based histomorphometry revealed that the 100mg/kg dose of TAM dose significantly increased trabecular bone formation and decreased periosteal bone formation at 1-week post-TAM treatment. Using the reporter mouse model Col1-CreERT2; mT/mG, we found that 10mg/kg TAM induced Col1-CreERT2 activity in bone at a comparable level to the 100mg/kg dose. TAM treatment at 100mg/kg/day × 4 days significantly affects bone homeostasis, resulting in an anabolic bone effect on trabecular bone in 1-month-old male mice. However, a lower dose of TAM at 10 mg/kg/day × 4 days can

  18. Effect of calcination conditions of pork bone sludge on behaviour

    Indian Academy of Sciences (India)

    ... bone sludge from meat plant via two essentially different calcination methods using ... tissue and suitability for further investigations intended for medical grafting. ... The Alfred Meissner Higher School of Dental Engineering and Humanities, ...

  19. Vaccination Games with Peer Effects in a Heterogeneous Hospital Worker Population

    Directory of Open Access Journals (Sweden)

    Troy Tassier

    2015-01-01

    Full Text Available We develop a game theoretic model to analyze the Nash equilibrium of vaccine decisions in a hospital population with heterogeneous contacts. We use the model in conjunction with person-to-person contact data within a large university hospital. We simulate, using agent-based models, the probability of infection for various worker types in the data and use these probabilities to identify the Nash equilibrium vaccine choices of hospital workers. The analysis suggests that there may be large differences in vaccination rates among hospital worker groups. We extend the model to include peer effects within the game. The peer effects may create additional equilibria or may further cement existing equilibria depending on parameter values. Further, depending on the magnitude of the peer effects and the costs of infection and vaccination, peer effects may increase or decrease differences in worker group vaccination rates within the hospital.

  20. Random Process Theory Approach to Geometric Heterogeneous Surfaces: Effective Fluid-Solid Interaction

    Science.gov (United States)

    Khlyupin, Aleksey; Aslyamov, Timur

    2017-06-01

    Realistic fluid-solid interaction potentials are essential in description of confined fluids especially in the case of geometric heterogeneous surfaces. Correlated random field is considered as a model of random surface with high geometric roughness. We provide the general theory of effective coarse-grained fluid-solid potential by proper averaging of the free energy of fluid molecules which interact with the solid media. This procedure is largely based on the theory of random processes. We apply first passage time probability problem and assume the local Markov properties of random surfaces. General expression of effective fluid-solid potential is obtained. In the case of small surface irregularities analytical approximation for effective potential is proposed. Both amorphous materials with large surface roughness and crystalline solids with several types of fcc lattices are considered. It is shown that the wider the lattice spacing in terms of molecular diameter of the fluid, the more obtained potentials differ from classical ones. A comparison with published Monte-Carlo simulations was discussed. The work provides a promising approach to explore how the random geometric heterogeneity affects on thermodynamic properties of the fluids.

  1. Effect of heterogeneity and assumed mode of inheritance on lod scores.

    Science.gov (United States)

    Durner, M; Greenberg, D A

    1992-02-01

    Heterogeneity is a major factor in many common, complex diseases and can confound linkage analysis. Using computer-simulated heterogeneous data we tested what effect unlinked families have on a linkage analysis when heterogeneity is not taken into account. We created 60 data sets of 40 nuclear families each with different proportions of linked and unlinked families and with different modes of inheritance. The ascertainment probability was 0.05, the disease had a penetrance of 0.6, and the recombination fraction for the linked families was zero. For the analysis we used a variety of assumed modes of inheritance and penetrances. Under these conditions we looked at the effect of the unlinked families on the lod score, the evaluation of the mode of inheritance, and the estimate of penetrance and of the recombination fraction in the linked families. 1. When the analysis was done under the correct mode of inheritance for the linked families, we found that the mode of inheritance of the unlinked families had minimal influence on the highest maximum lod score (MMLS) (i.e., we maximized the maximum lod score with respect to penetrance). Adding sporadic families decreased the MMLS less than adding recessive or dominant unlinked families. 2. The mixtures of dominant linked families with unlinked families always led to a higher MMLS when analyzed under the correct (dominant) mode of inheritance than when analyzed under the incorrect mode of inheritance. In the mixtures with recessive linked families, assuming the correct mode of inheritance generally led to a higher MMLS, but we observed broad variation.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Investigating the Abscopal Effects of Radioablation on Shielded Bone Marrow in Rodent Models Using Multimodality Imaging.

    Science.gov (United States)

    Afshar, Solmaz F; Zawaski, Janice A; Inoue, Taeko; Rendon, David A; Zieske, Arthur W; Punia, Jyotinder N; Sabek, Omaima M; Gaber, M Waleed

    2017-07-01

    The abscopal effect is the response to radiation at sites that are distant from the irradiated site of an organism, and it is thought to play a role in bone marrow (BM) recovery by initiating responses in the unirradiated bone marrow. Understanding the mechanism of this effect has applications in treating BM failure (BMF) and BM transplantation (BMT), and improving survival of nuclear disaster victims. Here, we investigated the use of multimodality imaging as a translational tool to longitudinally assess bone marrow recovery. We used positron emission tomography/computed tomography (PET/CT), magnetic resonance imaging (MRI) and optical imaging to quantify bone marrow activity, vascular response and marrow repopulation in fully and partially irradiated rodent models. We further measured the effects of radiation on serum cytokine levels, hematopoietic cell counts and histology. PET/CT imaging revealed a radiation-induced increase in proliferation in the shielded bone marrow (SBM) compared to exposed bone marrow (EBM) and sham controls. T 2 -weighted MRI showed radiation-induced hemorrhaging in the EBM and unirradiated SBM. In the EBM and SBM groups, we found alterations in serum cytokine and hormone levels and in hematopoietic cell population proportions, and histological evidence of osteoblast activation at the bone marrow interface. Importantly, we generated a BMT mouse model using fluorescent-labeled bone marrow donor cells and performed fluorescent imaging to reveal the migration of bone marrow cells from shielded to radioablated sites. Our study validates the use of multimodality imaging to monitor bone marrow recovery and provides evidence for the abscopal response in promoting bone marrow recovery after irradiation.

  3. Noninvasive markers of bone metabolism in the rhesus monkey: normal effects of age and gender

    Science.gov (United States)

    Cahoon, S.; Boden, S. D.; Gould, K. G.; Vailas, A. C.

    1996-01-01

    Measurement of bone turnover in conditions such as osteoporosis has been limited by the need for invasive iliac bone biopsy to reliably determine parameters of bone metabolism. Recent advances in the area of serum and urinary markers of bone metabolism have raised the possibility for noninvasive measurements; however, little nonhuman primate data exist for these parameters. The purpose of this experiment was to define the normal range and variability of several of the newer noninvasive bone markers which are currently under investigation in humans. The primary intent was to determine age and gender variability, as well as provide some normative data for future experiments in nonhuman primates. Twenty-four rhesus macaques were divided into equal groups of male and female according to the following age groupings: 3 years, 5-10 years, 15-20 years, and > 25 years. Urine was collected three times daily for a four-day period and measured for several markers of bone turnoverm including pyridinoline (PYD), deoxypyrodinoline (DPD), hydroxyproline, and creatinine. Bone mineral density measurements of the lumbar spine were performed at the beginning and end of the study period. Serum was also obtained at the time of bone densitometry for measurement of osteocalcin levels by radioimmunoassay. There were no significant differences in bone mineral density, urine PYD, or urine DPD based on gender. Bone density was lowest in the youngest animals, peaked in the 15-20-year group, but again decreased in the oldest animals. The osteocalcin, PYD, and DPD levels followed an inversely related pattern to bone density. The most important result was the relative age insensitivity of the ratio of PYD:DPD in monkeys up to age 20 years. Since bone density changes take months or years to become measurable and iliac biopsies are invasive, the PYD/DPD marker ratio may have important implications for rapid noninvasive measurement of the effects of potential treatments for osteoporosis in the non

  4. The effects of hypercapnia on cortical capillary transit time heterogeneity (CTH) in anesthetized mice

    DEFF Research Database (Denmark)

    Gutiérrez-Jiménez, Eugenio; Angleys, Hugo; Rasmussen, Peter Mondrup

    2018-01-01

    Capillary flow patterns are highly heterogeneous in the resting brain. During hyperemia, capillary transit-time heterogeneity (CTH) decreases, in proportion to blood's mean transit time (MTT) in passive, compliant microvascular networks. Previously, we found that functional activation reduces...

  5. Effects of drilling parameters in numerical simulation to the bone temperature elevation

    Science.gov (United States)

    Akhbar, Mohd Faizal Ali; Malik, Mukhtar; Yusoff, Ahmad Razlan

    2018-04-01

    Drilling into the bone can produce significant amount of heat which can cause bone necrosis. Understanding the drilling parameters influence to the heat generation is necessary to prevent thermal necrosis to the bone. The aim of this study is to investigate the influence of drilling parameters on bone temperature elevation. Drilling simulations of various combinations of drill bit diameter, rotational speed and feed rate were performed using finite element software DEFORM-3D. Full-factorial design of experiments (DOE) and two way analysis of variance (ANOVA) were utilised to examine the effect of drilling parameters and their interaction influence on the bone temperature. The maximum bone temperature elevation of 58% was demonstrated within the range in this study. Feed rate was found to be the main parameter to influence the bone temperature elevation during the drilling process followed by drill diameter and rotational speed. The interaction between drill bit diameter and feed rate was found to be significantly influence the bone temperature. It is discovered that the use of low rotational speed, small drill bit diameter and high feed rate are able to minimize the elevation of bone temperature for safer surgical operations.

  6. The effects of odontogenic and nonodontogenic tissues on bone healing in Guinea pig mandible

    International Nuclear Information System (INIS)

    Kim, So Jung; Hwang, Eui Hwan; Lee, Sang Rae; Hong, Jung Pyo

    1996-01-01

    This study was for comparing healing patterns and effects between with odontogenic and nonodontogenic tissues on the defected mandible. Experimental bone defects that measured 3 mm in diameter were created on the mandibular body of guinea pig by removal of bone with the use of trephine burs and bone defects were grafted with Biogran (Orthovita Co., U.S. A.) and covered with Dura Mata (Pfrimmer-Viggo GmbH Co., Germany). Guinea pigs were serially terminated by fours on the 3 days, the 1 week, the 2 weeks, the 3 weeks, the 4 weeks, and the 5 weeks after experiment, and the mandibular body was removed and fixed with 10% neutral formalin. They were decalcified and embedded in paraffin as using the usual methods. The specimen sectioned and stained with hematoxylin and eosin and toluidine blue. They were observed with a light microscope and a polarizing microscope. The obtained results were as follows: 1. Defected bone was healed fast from the odontogenic tissues in early stage of the experiment. 2. The arrangement of the bone matrix was relatively regular in the bone from the nonodontogenic tissues, but irregular in the bone from the odotogenic tissues. 3. Compact bone has started to be absorbed and changed to the pattern of matrix bone tissue from 3 weeks after experiment.

  7. Effects and Complications of Bone-Marrow Transplantation in Man

    Energy Technology Data Exchange (ETDEWEB)

    Mathe, G.; Schwarzenberg, L.; Miel, J.L. A; Schneider, M.; Cattan, A.; Schlumberger, J. R. [Institut de cancerologie et immunogenetique, Hopital Paul Brousse, Villejuif (France)

    1969-07-15

    Full text: Allogenic bone-marrow grafting in 24 human leukaemic subjects is described. The graft failed in 7 cases and took in 17 cases. In the latter group, all 17 cases were complicated by the secondary syndrome which was-fatal in 13 cases and controlled in 4 cases. The immunogenetic and immunological factors determining the establishment and evolution of haematological radiochimeras in man are discussed. The choice of donor is fundamental. Three tests are effective in donor selection, the indirect histocompatibility test, the leucocyte antigen test and the reaction of donor and recipient leucocytes in the dermis of an irradiated hamster. When marrow from several donors is transfused, the recipient spontaneously selects the genetically nearest. It seems likely there is more chance of finding a suitable donor among genetically related subjects than among those who are unrelated. The frequency of graft take seems slightly lower in recipients who have previously received blood transfusions. Total bone-marrow graft is associated with specific tolerance towards donor tissues. This is paralleled by the production in the chimera of immunoglobulins produced by the graft. The secondary syndrome seems, as in animals, to be related essentially to the graft-versus-host reaction. It is convenient to distinguish among its various manifestations, on the one hand, those lesions which are readily controlled such as hepatitis or erythrodermia associated with infiltration and proliferation of immunologically competent cells from the graft and, on the other hand, immune insufficiency with regard to micro-organisms, especially viruses and Candida albicans. This latter group, the mechanism of which is complex, still eludes attempts at preventive and curative control. The use of multiple donors and the administration of cortisone during marrow transfusion and A-methopterin and/or cyclophosphamide in the days following transfusions; seem to have reduced the severity of the secondary

  8. BEYOND GLYCEMIC CONTROL IN DIABETES MELLITUS: EFFECTS OF INCRETIN-BASED THERAPY ON BONE METABOLISM

    Directory of Open Access Journals (Sweden)

    ELENA eCECCARELLI

    2013-06-01

    Full Text Available Diabetes mellitus (DM and osteoporosis (OP are common disorders with a significant health burden, and an increase in fracture risk has been described both in type 1 (T1DM and in type 2 (T2DM diabetes. The pathogenic mechanisms of impaired skeletal strength in diabetes remain to be clarified in details and they are only in part reflected by a variation in bone mineral density (BMD. In T2DM, the occurrence of low bone turnover together with a decreased osteoblast activity and compromised bone quality has been shown. Of note, some antidiabetic drugs (e.g. tiazolidinediones, insulin may deeply affect bone metabolism. In addition, the recently introduced class of incretin-based drugs (i.e. GLP-1 receptor agonists and DPP-4 inhibitors is expected to exert potentially beneficial effects on bone health, possibly due to a bone anabolic activity of GLP-1, that can be either direct or indirect through the involvement of thyroid C cells.Here we will review the established as well as the putative effects of incretin hormones and of incretin-based drugs on bone metabolism, both in preclinical models and in man, taking into account that such therapeutic strategy may be effective not only to achieve a good glycemic control, but also to improve bone health in diabetic patients.

  9. Effect of strontium addition and chitosan concentration variation on cytotoxicity of chitosan-alginate-carbonate apatite based bone scaffold

    Science.gov (United States)

    Perkasa, Rilis Eka; Umniati, B. Sri; Sunendar, Bambang

    2017-09-01

    Bone scaffold is one of the most important component in bone tissue engineering. Basically, bone scaffold is a biocompatible structure designed to replace broken bone tissue temporarily. Unlike conventional bone replacements, an advanced bone scaffold should be bioactive (e.g: supporting bone growth) and biodegradable as new bone tissue grow, while retain its mechanical properties similarity with bone. It is also possible to add more bioactive substrates to bone scaffold to further support its performance. One of the substrate is strontium, an element that could improve the ability of the bone to repair itself. However, it must be noted that excessive consumption of strontium could lead to toxicity and diseases, such as osteomalacia and hypocalcemia. This research aimed to investigate the effect of strontium addition to the cytotoxic property of chitosan-alginate-carbonate apatite bone scaffold. The amount of strontium added to the bone scaffold was 5% molar of the carbonate apatite content. As a control, bone scaffold without stronsium (0% molar) were also made. The effect of chitosan concentration variation on the cytotoxicity were also observed, where the concentration varies on 1% and 3% w/v of chitosan solution. The results showed an optimum result on bone scaffold sample with 5% molar of strontium and 3% chitosan, where 87.67% cells in the performed MTS-Assay cytotoxicity testing survived. This showed that the use of up to 5% molar addition of strontium and 3% chitosan could enhance the survivability of the cell.

  10. Effect of Hydroxyapatite on Bone Integration in a Rabbit Tibial Defect Model

    Science.gov (United States)

    Sohn, Sung-Keun; Kim, Kyung-Taek; Kim, Chul-Hong; Ahn, Hee-Bae; Rho, Mee-Sook; Jeong, Min-Ho; Sun, Sang-Kyu

    2010-01-01

    Background The aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study. Methods Ten rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting. Results The HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged. Conclusions We concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite cylinder showed better results for the sustained morphology. PMID:20514266

  11. Effect of droplet size on the droplet behavior on the heterogeneous surface

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ho Yeon; Son, Sung Wan; Ha, ManYeong [Pusan National University, Busan (Korea, Republic of); Park, Yong Gap [Pusan National University, Busan (Korea, Republic of)

    2017-06-15

    The characteristics of a three-dimensional hemispherical droplet on a heterogeneous surface were studied using the Lattice Boltzmann method (LBM). The hydrophilic surface has a hydrophobic part at the center. The hemispherical droplets are located at the center of the heterogeneous surface. According to the contact angles of hydrophilic and hydrophobic bottom surfaces, the droplet either separates or reaches a new equilibrium state. The separation time varies according to the change in droplet size, and it affects the status of droplet separation. The droplet separation behavior was investigated by analyzing the velocity vector around the phase boundary line. The shape and separation time of a droplet are determined by the contact angle of each surface. The speed of droplet separation increases as the difference in contact angle increases between the hydrophobic surface and hydrophilic surface. The separation status and the separation time of a droplet are also determined by the change of the droplet size. As the size of the droplet decreases, the effect of surface tension decreases, and the separation time of the droplet also decreases. On the other hand, as the droplet becomes larger, the effect of surface tension increases and the time required for the droplet to separate also increases.

  12. Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control

    Science.gov (United States)

    Zhao, Ling; Xia, Huifen

    2018-01-01

    The project of polymer flooding has achieved great success in Daqing oilfield, and the main oil reservoir recovery can be improved by more than 15%. But, for some strong oil reservoir heterogeneity carrying out polymer flooding, polymer solution will be inefficient and invalid loop problem in the high permeability layer, then cause the larger polymer volume, and a significant reduction in the polymer flooding efficiency. Aiming at this problem, it is studied the method that improves heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control. The research results show that the polymer physical and chemical reaction of positively-charged gel with the residual polymer in high permeability layer can generate three-dimensional network of polymer, plugging high permeable layer, and increase injection pressure gradient, then improve the effect of polymer flooding development. Under the condition of the same dosage, positively-charged gel profile control can improve the polymer flooding recovery factor by 2.3∼3.8 percentage points. Under the condition of the same polymer flooding recovery factor increase value, after positively-charged gel profile control, it can reduce the polymer volume by 50 %. Applying mechanism of positively-charged gel profile control technology is feasible, cost savings, simple construction, and no environmental pollution, therefore has good application prospect.

  13. Experimental investigation on improving the removal effect of WFGD system on fine particles by heterogeneous condensation

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Jingjing; Yang, Linjun; Yan, Jinpei; Xiong, Guilong; Shen, Xianglin [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Heterogeneous condensation of water vapor as a preconditioning technique for the removal of fine particles from flue gas was investigated experimentally in a wet flue gas desulfurization (WFGD) system. A supersaturated vapor phase, necessary for condensational growth of fine particles, was achieved in the SO{sub 2} absorption zone and at the top of the wet FGD scrubber by adding steam in the gas inlet and above the scrubbing liquid inlet of the scrubber, respectively. The condensational grown droplets were then removed by the scrubbing liquid and a high-efficiency demister. The results show that the effectiveness of the WFGD system for removal of fine particles is related to the SO{sub 2} absorbent and the types of scrubber employed. Despite a little better effectiveness for the removal of fine particles in the rotating-stream-tray scrubber at the same liquid-to-gas ratio, The similar trends are obtained between the spray scrubber and rotating-stream-tray scrubber. Due to the formation of aerosol particles in the limestone and ammonia-based FGD processes, the fine particle removal efficiencies are lower than those for Na{sub 2}CO{sub 3} and water. The performance of the WFGD system for removal of fine particles can be significantly improved for both steam addition cases, for which the removal efficiency increases with increasing amount of added steam. A high liquid to gas ratio is beneficial for efficient removal of fine particles by heterogeneous condensation of water vapor.

  14. Investigations on the heterogenous catalytic hydrogenation using isotope effect and gamma- and neutron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kudlacek, R; Cabicar, J [Ceske Vysoke Uceni Technicke, Prague (Czechoslovakia). Katedra Jaderne Chemie

    1976-01-01

    The kinetic and solvent isotope effects during the maleic acid heterogeneous catalytic hydrogenation and deuteration in light and heavy water have been studied. Also the effect of the gamma and neutron irradiation on the Ni-ZnO catalysts (with various ratios of components) on the reaction kinetics and mechanism has been measured, as well as the effect of pH on the adsorption behaviour of maleic acid and the temperature dependence of the reaction rate. Existence of different adsorption centers for hydrogen and maleic acid could be deduced from these experiments. A reaction mechanism based on the two-dimensional diffusion of components in the surface is proposed. The catalyst is formed from Ni and ZnO-microspheres. Hydrogen is bound to nickel and maleic acid is adsorbed on the ZnO-microspheres. The reaction takes place on the boundary layers of these microspheres.

  15. Effects of genes, sex, age, and activity on BMC, bone size, and areal and volumetric BMD.

    Science.gov (United States)

    Havill, Lorena M; Mahaney, Michael C; L Binkley, Teresa; Specker, Bonny L

    2007-05-01

    Quantitative genetic analyses of bone data for 710 inter-related individuals 8-85 yr of age found high heritability estimates for BMC, bone area, and areal and volumetric BMD that varied across bone sites. Activity levels, especially time in moderate plus vigorous activity, had notable effects on bone. In some cases, these effects were age and sex specific. Genetic and environmental factors play a complex role in determining BMC, bone size, and BMD. This study assessed the heritability of bone measures; characterized the effects of age, sex, and physical activity on bone; and tested for age- and sex-specific bone effects of activity. Measures of bone size and areal and volumetric density (aBMD and vBMD, respectively) were obtained by DXA and pQCT on 710 related individuals (466 women) 8-85 yr of age. Measures of activity included percent time in moderate + vigorous activity (%ModVig), stair flights climbed per day, and miles walked per day. Quantitative genetic analyses were conducted to model the effects of activity and covariates on bone outcomes. Accounting for effects of age, sex, and activity levels, genes explained 40-62% of the residual variation in BMC and BMD and 27-75% in bone size (all pBMC and cross-sectional area (CSA) at the 4% radius, but this was not observed among women (sex-by-activity interaction, both p bone sites. Percent time spent in moderate to vigorous activity had the most notable effect on bone, and in some cases, this effect was age or sex specific.

  16. Vitamin D, muscle and bone: Integrating effects in development, aging and injury.

    Science.gov (United States)

    Girgis, Christian M; Baldock, Paul A; Downes, Michael

    2015-07-15

    Beyond the established effects of muscle loading on bone, a complex network of hormones and growth factors integrates these adjacent tissues. One such hormone, vitamin D, exerts broad-ranging effects in muscle and bone calcium handling, differentiation and development. Vitamin D also modulates muscle and bone-derived hormones, potentially facilitating cross-talk between these tissues. In the clinical setting, vitamin D deficiency or mutations of the vitamin D receptor result in generalized atrophy of muscle and bone, suggesting coordinated effects of vitamin D at these sites. In this review, we discuss emerging evidence that vitamin D exerts specific effects throughout the life of the musculoskeletal system - in development, aging and injury. From this holistic viewpoint, we offer new insights into an old debate: whether vitamin D's effects in the musculoskeletal system are direct via local VDR signals or indirect via its systemic effects in calcium and phosphate homeostasis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Effects of heterogeneous wealth distribution on public cooperation with collective risk

    Science.gov (United States)

    Wang, Jing; Fu, Feng; Wang, Long

    2010-07-01

    The distribution of wealth among individuals in real society can be well described by the Pareto principle or “80-20 rule.” How does such heterogeneity in initial wealth distribution affect the emergence of public cooperation, when individuals, the rich and the poor, engage in a collective-risk enterprise, not to gain a profit but to avoid a potential loss? Here we address this issue by studying a simple but effective model based on threshold public goods games. We analyze the evolutionary dynamics for two distinct scenarios, respectively: one with fair sharers versus defectors and the other with altruists versus defectors. For both scenarios, particularly, we in detail study the dynamics of the population with dichotomic initial wealth—the rich versus the poor. Moreover, we demonstrate the possible steady compositions of the population and provide the conditions for stability of these steady states. We prove that in a population with heterogeneous wealth distribution, richer individuals are more likely to cooperate than poorer ones. Participants with lower initial wealth may choose to cooperate only if all players richer than them are cooperators. The emergence of pubic cooperation largely relies on rich individuals. Furthermore, whenever the wealth gap between the rich and the poor is sufficiently large, cooperation of a few rich individuals can substantially elevate the overall level of social cooperation, which is in line with the well-known Pareto principle. Our work may offer an insight into the emergence of cooperative behavior in real social situations where heterogeneous distribution of wealth among individual is omnipresent.

  18. The effect of organic coating on the heterogeneous ice nucleation efficiency of mineral dust aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Moehler, O; Benz, S; Saathoff, H; Schnaiter, M; Wagner, R [Forschungszentrum Karlsruhe, Institute for Meteorology and Climate Research, 76021 Karlsruhe (Germany); Schneider, J; Walter, S [Max Planck Institute for Chemistry, 55128 Mainz (Germany); Ebert, V; Wagner, S [University of Heidelberg, Institute for Physical Chemistry, 69120 Heidelberg (Germany)], E-mail: Ottmar.Moehler@imk.fzk.de

    2008-04-15

    The effect of organic coating on the heterogeneous ice nucleation (IN) efficiency of dust particles was investigated at simulated cirrus cloud conditions in the AIDA cloud chamber of Forschungszentrum Karlsruhe. Arizona test dust (ATD) and the clay mineral illite were used as surrogates for atmospheric dust aerosols. The dry dust samples were dispersed into a 3.7 m{sup 3} aerosol vessel and either directly transferred into the 84 m{sup 3} cloud simulation chamber or coated before with the semi-volatile products from the reaction of {alpha}-pinene with ozone in order to mimic the coating of atmospheric dust particles with secondary organic aerosol (SOA) substances. The ice-active fraction was measured in AIDA expansion cooling experiments as a function of the relative humidity with respect to ice, RHi, in the temperature range from 205 to 210 K. Almost all uncoated dust particles with diameters between 0.1 and 1.0 {mu}m acted as efficient deposition mode ice nuclei at RHi between 105 and 120%. This high ice nucleation efficiency was markedly suppressed by coating with SOA. About 20% of the ATD particles coated with a SOA mass fraction of 17 wt% were ice-active at RHi between 115 and 130%, and only 10% of the illite particles coated with an SOA mass fraction of 41 wt% were ice-active at RHi between 160 and 170%. Only a minor fraction of pure SOA particles were ice-active at RHi between 150 and 190%. Strong IN activation of SOA particles was observed only at RHi above 200%, which is clearly above water saturation at the given temperature. The IN suppression and the shift of the heterogeneous IN onset to higher RHi seem to depend on the coating thickness or the fractional surface coverage of the mineral particles. The results indicate that the heterogeneous ice nucleation potential of atmospheric mineral particles may also be suppressed if they are coated with secondary organics.

  19. The effect of organic coating on the heterogeneous ice nucleation efficiency of mineral dust aerosols

    International Nuclear Information System (INIS)

    Moehler, O; Benz, S; Saathoff, H; Schnaiter, M; Wagner, R; Schneider, J; Walter, S; Ebert, V; Wagner, S

    2008-01-01

    The effect of organic coating on the heterogeneous ice nucleation (IN) efficiency of dust particles was investigated at simulated cirrus cloud conditions in the AIDA cloud chamber of Forschungszentrum Karlsruhe. Arizona test dust (ATD) and the clay mineral illite were used as surrogates for atmospheric dust aerosols. The dry dust samples were dispersed into a 3.7 m 3 aerosol vessel and either directly transferred into the 84 m 3 cloud simulation chamber or coated before with the semi-volatile products from the reaction of α-pinene with ozone in order to mimic the coating of atmospheric dust particles with secondary organic aerosol (SOA) substances. The ice-active fraction was measured in AIDA expansion cooling experiments as a function of the relative humidity with respect to ice, RHi, in the temperature range from 205 to 210 K. Almost all uncoated dust particles with diameters between 0.1 and 1.0 μm acted as efficient deposition mode ice nuclei at RHi between 105 and 120%. This high ice nucleation efficiency was markedly suppressed by coating with SOA. About 20% of the ATD particles coated with a SOA mass fraction of 17 wt% were ice-active at RHi between 115 and 130%, and only 10% of the illite particles coated with an SOA mass fraction of 41 wt% were ice-active at RHi between 160 and 170%. Only a minor fraction of pure SOA particles were ice-active at RHi between 150 and 190%. Strong IN activation of SOA particles was observed only at RHi above 200%, which is clearly above water saturation at the given temperature. The IN suppression and the shift of the heterogeneous IN onset to higher RHi seem to depend on the coating thickness or the fractional surface coverage of the mineral particles. The results indicate that the heterogeneous ice nucleation potential of atmospheric mineral particles may also be suppressed if they are coated with secondary organics

  20. Effects of upper mantle heterogeneities on the lithospheric stress field and dynamic topography

    Science.gov (United States)

    Osei Tutu, Anthony; Steinberger, Bernhard; Sobolev, Stephan V.; Rogozhina, Irina; Popov, Anton A.

    2018-05-01

    The orientation and tectonic regime of the observed crustal/lithospheric stress field contribute to our knowledge of different deformation processes occurring within the Earth's crust and lithosphere. In this study, we analyze the influence of the thermal and density structure of the upper mantle on the lithospheric stress field and topography. We use a 3-D lithosphere-asthenosphere numerical model with power-law rheology, coupled to a spectral mantle flow code at 300 km depth. Our results are validated against the World Stress Map 2016 (WSM2016) and the observation-based residual topography. We derive the upper mantle thermal structure from either a heat flow model combined with a seafloor age model (TM1) or a global S-wave velocity model (TM2). We show that lateral density heterogeneities in the upper 300 km have a limited influence on the modeled horizontal stress field as opposed to the resulting dynamic topography that appears more sensitive to such heterogeneities. The modeled stress field directions, using only the mantle heterogeneities below 300 km, are not perturbed much when the effects of lithosphere and crust above 300 km are added. In contrast, modeled stress magnitudes and dynamic topography are to a greater extent controlled by the upper mantle density structure. After correction for the chemical depletion of continents, the TM2 model leads to a much better fit with the observed residual topography giving a good correlation of 0.51 in continents, but this correction leads to no significant improvement of the fit between the WSM2016 and the resulting lithosphere stresses. In continental regions with abundant heat flow data, TM1 results in relatively small angular misfits. For example, in western Europe the misfit between the modeled and observation-based stress is 18.3°. Our findings emphasize that the relative contributions coming from shallow and deep mantle dynamic forces are quite different for the lithospheric stress field and dynamic

  1. Effects of heterogeneous wealth distribution on public cooperation with collective risk.

    Science.gov (United States)

    Wang, Jing; Fu, Feng; Wang, Long

    2010-07-01

    The distribution of wealth among individuals in real society can be well described by the Pareto principle or "80-20 rule." How does such heterogeneity in initial wealth distribution affect the emergence of public cooperation, when individuals, the rich and the poor, engage in a collective-risk enterprise, not to gain a profit but to avoid a potential loss? Here we address this issue by studying a simple but effective model based on threshold public goods games. We analyze the evolutionary dynamics for two distinct scenarios, respectively: one with fair sharers versus defectors and the other with altruists versus defectors. For both scenarios, particularly, we in detail study the dynamics of the population with dichotomic initial wealth-the rich versus the poor. Moreover, we demonstrate the possible steady compositions of the population and provide the conditions for stability of these steady states. We prove that in a population with heterogeneous wealth distribution, richer individuals are more likely to cooperate than poorer ones. Participants with lower initial wealth may choose to cooperate only if all players richer than them are cooperators. The emergence of pubic cooperation largely relies on rich individuals. Furthermore, whenever the wealth gap between the rich and the poor is sufficiently large, cooperation of a few rich individuals can substantially elevate the overall level of social cooperation, which is in line with the well-known Pareto principle. Our work may offer an insight into the emergence of cooperative behavior in real social situations where heterogeneous distribution of wealth among individual is omnipresent.

  2. Effects of temperature on the heterogeneous oxidation of sulfur dioxide by ozone on calcium carbonate

    Directory of Open Access Journals (Sweden)

    L. Y. Wu

    2011-07-01

    Full Text Available The heterogeneous oxidation of sulfur dioxide by ozone on CaCO3 was studied as a function of temperature (230 to 298 K at ambient pressure. Oxidation reactions were followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS to obtain kinetic and mechanistic data. From the analysis of the spectral features, the formation of sulfate was identified on the surface in the presence of O3 and SO2 at different temperatures from 230 to 298 K. The results showed that the heterogeneous oxidation and the rate of sulfate formation were sensitive to temperature. An interesting stage-transition region was observed at temperatures ranging from 230 to 257 K, but it became ambiguous gradually above 257 K. The reactive uptake coefficients at different temperatures from 230 to 298 K were acquired for the first time, which can be used directly in atmospheric chemistry modeling studies to predict the formation of secondary sulfate aerosol in the troposphere. Furthermore, the rate of sulfate formation had a turning point at about 250 K. The sulfate concentration at 250 K was about twice as large as that at 298 K. The rate of sulfate formation increased with decreasing temperature at temperatures above 250 K, while there is a contrary temperature effect at temperatures below 250 K. The activation energy for heterogeneous oxidation at temperatures from 245 K to 230 K was determined to be 14.63 ± 0.20 kJ mol−1. A mechanism for the temperature dependence was proposed and the atmospheric implications were discussed.

  3. Wetting at the nanometer scale: effects of long-range forces and substrate heterogeneities

    International Nuclear Information System (INIS)

    Checco, Antonio

    2003-01-01

    Wetting phenomena on the nano-scale remain poorly understood in spite of their growing theoretical and practical interest. In this context, the present work aimed at studying partial wetting of nanometer-sized alkane droplets on 'model' surfaces build by self-assembly of organic monolayers. For this purpose a novel technique, based on 'noncontact' Atomic Force Microscopy (AFM), has been developed to image, with minimal artefacts, drops of adjustable size directly condensed on so- lid surfaces. We have thus shown that contact angle of alkanes, wetting a weakly heterogeneous, silanized substrate, noticeably decreases from its macroscopic value for droplets sizes in the submicron range. The line tension, arising in this case from purely dispersive long-range interactions between the liquid and the substrate, is theoretically too weak to be responsible for the observed effect. Therefore we have supposed that contact angle is affected by mesoscopic chemical heterogeneities of the substrate whenever the droplets size becomes sufficiently small. This scenario has been supported by numerical simulations based on a simplified model of the spatial distribution of surface defects. Similar experiments, performed on different substrates (monolayers made of alkane-thiols self-assembled on gold and of alkyl chains covalently bound onto a silicon surface), have also shown that wetting on small scales is strongly affected by minimal physical and chemical surface heterogeneities. Finally, to provide further examples of the potential of the above mentioned AFM technique, we have studied the wettability of nano-structured surfaces and the local wetting properties of hair. (author) [fr

  4. Synergistic effects of dimethyloxallyl glycine and recombinant human bone morphogenetic protein-2 on repair of critical-sized bone defects in rats

    Science.gov (United States)

    Qi, Xin; Liu, Yang; Ding, Zhen-Yu; Cao, Jia-Qing; Huang, Jing-Huan; Zhang, Jie-Yuan; Jia, Wei-Tao; Wang, Jing; Liu, Chang-Sheng; Li, Xiao-Lin

    2017-02-01

    In bone remodeling, osteogenesis is closely coupled to angiogenesis. Bone tissue engineering using multifunctional bioactive materials is a promising technique which has the ability to simultaneously stimulate osteogenesis and angiogenesis for repair of bone defects. We developed mesoporous bioactive glass (MBG)-doped poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds as delivery vehicle. Two bioactive molecules, dimethyloxalylglycine (DMOG), a small-molecule angiogenic drug, and recombinant human bone morphogenetic protein-2 (rhBMP-2), an osteoinductive growth factor, were co-incorporated into the scaffold. The synergistic effects of DMOG and rhBMP-2 released in the composite scaffolds on osteogenic and angiogenic differentiation of hBMSCs were investigated using real-time quantitative polymerase chain reaction and western blotting. Moreover, in vivo studies were conducted to observe bone regeneration and vascular formation of critical-sized bone defects in rats using micro-computed tomography, histological analyses, Microfil® perfusion, fluorescence labeling, and immunohistochemical analysis. The results showed that DMOG and rhBMP-2 released in the MBG-PHBHHx scaffolds did exert synergistic effects on the osteogenic and angiogenic differentiation of hBMSCs. Moreover, DMOG and rhBMP-2 produced significant increases in newly-formed bone and neovascularization of calvarial bone defects in rats. It is concluded that the co-delivery strategy of both rhBMP-2 and DMOG can significantly improve the critical-sized bone regeneration.

  5. Evaluation of follow-up bone scintigraphy for assessing the effects of hormone and chemotherapy of bone metastases from prostatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Nobuaki; Ito, Yasuhiko; Morita, Rikushi; Yoneda, Masaya; Muranaka, Akira [Kawasaki Medical School, Kurashiki, Okayama (Japan)

    1983-08-01

    To assess the clinical usefulness of bone scintigraphy for the osseous metastases of prostatic cancer after treatment, we attempted the correlative studies on laboratory data (TAP, PAP, ALP, and LDH) and scintigraphy. In 77 patients with prostatic cancer, bone scintigraphies were performed with sup(99m)Tc-phosphorous compounds to detect bone metastases. In 34 cases (44 %) bone metastases were detected. In 21 patients out of them, we assessed the effects of hormone and chemotherapy for bone metastases using serial bone scintigraphy. In 19 cases (24.7 %) of the bone scintigraphy showed equivocal results. Of 21 patients with bone metastases, 15 patients showed improvement on scintigram after hormone or chemotherapy. In much improved group (5 patients) and moderately improved group (5 patients), TAP and PAP levels were low and stable. On the other hand, in slightly improved group (5 patients) which showed partially effective on scintigram after treatment, serum TAP and PAP level were unstable. Some cases in the group of which the 1st scintigrams showed normal were turned to positive on scintigram, while TAP, PAP, ALP and LDH level were not elevated. Therefore, follow-up bone scintigraphies have value in evaluating the disease extent in patients with prostatic carcinoma.

  6. The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.

    Science.gov (United States)

    Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

    2014-04-01

    High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network

  7. Effects of occlusal inclination and loading on mandibular bone remodeling: a finite element study.

    Science.gov (United States)

    Rungsiyakull, Chaiy; Rungsiyakull, Pimdeun; Li, Qing; Li, Wei; Swain, Michael

    2011-01-01

    To provide a preliminary understanding of the biomechanics with respect to the effect of cusp inclination and occlusal loading on the mandibular bone remodeling. Three different cusp inclinations (0, 10, and 30 degrees) of a ceramic crown and different occlusal loading locations (central fossa and 1- and 2-mm offsets horizontally) were taken into account to explore the stresses and strains transferred from the crown to the surrounding dental bone through the implant. A strain energy density obtained from two-dimensional plane-strain finite element analysis was used as the mechanical stimulus to drive cancellous and cortical bone remodeling in a buccolingual mandibular section. Different ceramic cusp inclinations had a significant effect on bone remodeling responses in terms of the change in the average peri-implant bone density and overall stability. The remodeling rate was relatively high in the first few months of loading and gradually decreased until reaching its equilibrium. A larger cusp inclination and horizontal offset (eg, 30 degrees and 2-mm offset) led to a higher bone remodeling rate and greater interfacial stress. The dental implant superstructure design (in terms of cusp inclination and loading location) determines the load transmission pattern and thus largely affects bone remodeling activities. Although the design with a lower cusp inclination recommended in previous studies may reduce damage and fracture failure, it could, to a certain extent, compromise bone engagement and long-term stability.

  8. Effects of the hexahydroxyhexane myoinositol on bone uptake of radiocalcium in rats: Effect of inositol and vitamin D2 on bone uptake of 45Ca in rats

    International Nuclear Information System (INIS)

    Angeloff, L.G.; Skoryna, S.C.; Henderson, I.W.D.

    1977-01-01

    The objective of this study was to investigate the effects of inositol and vitamin D 2 on bone uptake of 45 Ca in rats. The radioactive calcium was administered to young rats by orogastric intubation (2 μci/100 g body weight (b.wt.)) with inositol (20 mg/100 g b.wt) and/or vitamin D 2 (500 IU/100g b.wt) to normal rats. Bone uptake of 45 Ca was measured after 24 hours by standard technique. Inositol alone produced a 48% increase in calcium uptake. It is concluded that inositol significantly increases bone uptake to radioactive calcium (P>0.005). Simultaneous administration of vitamin D 2 decreases the effect of inositol considerably, while vitamin D 2 has no significant effect. (author)

  9. The Effect of Liquid Nitrogen on Bone Graft Survival.

    Science.gov (United States)

    Sirinoglu, Hakan; Çilingir, Özlem Tuğçe; Çelebiler, Ozhan; Ercan, Feriha; Numanoglu, Ayhan

    2015-08-01

    Liquid nitrogen is used in medicine for cancer treatment and tissue preservation; however, bone viability after its application is controversial. This study aims to evaluate both the tissue viability and the clinical and histopathologic findings following liquid nitrogen application with different thawing techniques in rats. Mandibular bone grafts were taken from 45 Wistar rats and freezed in liquid nitrogen for 20 minutes. In the rapid-thawing technique (Rapid Thawing-1, Rapid Thawing-2), the grafts were held for 20 minutes in room temperature; in the slow-thawing technique (Slow Thawing-1, Slow Thawing-2), 20 minutes in -20°C, 20 minutes in +4°C, and 20 minutes in room temperature, respectively. In Rapid Thawing-2 and Slow Thawing-2 groups, autografts were implanted to their origin for 3 weeks and bone staining with India ink was performed and samples taken for histologic examination. The amount of cells and blood vessels and the density of bone canaliculi were significantly reduced in Rapid Thawing-1 and Slow Thawing-1 groups comparing to the Control group. However, the reduction rate was more significant in the Slow Thawing-1 group. Histomorphometric evaluation of the healing autografts after 3 weeks revealed that the decreased amounts of canaliculi were not changed in Slow Thawing-2 group. The study results demonstrated that bone tissue survives after liquid nitrogen treatment regardless of the performed thawing technique; however, slow thawing causes more tissue damage and metabolism impairment. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  10. Bone mineral density and bone markers in patients with a recent low-energy fracture: effect of 1 y of treatment with calcium and vitamin D

    DEFF Research Database (Denmark)

    Hitz, Mette F; Jensen, Jens-Erik B; Eskildsen, Peter C

    2007-01-01

    BACKGROUND: Low-energy fractures of the hip, forearm, shoulder, and spine are known consequences of osteoporosis. OBJECTIVE: We evaluated the effect of 1 y of treatment with calcium and vitamin D on bone mineral density (BMD) and bone markers in patients with a recent low-energy fracture. DESIGN...

  11. Effects of chronic mild stress on parameters of bone assessment in adult male and female rats

    Directory of Open Access Journals (Sweden)

    Fabrício L. Valente

    Full Text Available Abstract: Osteoporosis is a multifactorial disease of high prevalence and has great impact on quality of life, because the effects on bone structure increase the risk of fractures, what may be very debilitating. Based on the observation that patients with depression have lower bone mineral density than healthy individuals, many studies have indicated that stress could be an aggravating factor for bone loss. This study evaluates the effect of a protocol of chronic mild stress (CMS on parameters of bone assessment in male and female rats. Five 5-monh-old rats of each sex underwent a schedule of stressor application for 28 days. Stressors included cold, heat, restraint, cage tilt, isolation, overnight illumination, and water and food deprivation. Five rats of each sex were kept under minimum intervention as control group. The animals were weighed at beginning and end of the period, and after euthanasia had their bones harvested. Femur, tibia and lumbar vertebrae were analyzed by bone densitometry. Biomechanical tests were performed in femoral head and diaphysis. Trabecular bone volume was obtained from histomorphometric analysis of femoral head and vertebral body, as well as of femoral midshaft cross-sectional measures. Not all parameters analyzed showed effect of CMS. However, tibial and L4 vertebral bone mineral density and cross-sectional cortical/medullar ratio of femoral shaft were lower in female rats submitted to the CMS protocol. Among male rats, the differences were significant for femoral trabecular bone volume and maximum load obtained by biomechanical test. Thus, it could be confirmed that CMS can affect the balance of bone homeostasis in rats, what may contribute to the establishment of osteopenia or osteoporosis.

  12. Effects of treadmill exercise on cortical bone in the third metacarpus of young horses

    International Nuclear Information System (INIS)

    McCarthy, R.N.; Jeffcott, L.B.

    1992-01-01

    The effects of exercise and relative inactivity on cortical bone were compared in young horses. Two groups were used; one was given a 14-week programme of exercise (n = 6) and the other kept as unexercised controls (n = 6). The first nine weeks of exercise involved trotting and cantering (2 to 4 km d-1 at speeds up to 12 m s-1) on a treadmill set at an incline of 3 degrees. Over the next five weeks the horses were trained at near maximal speeds (that is, up to 14.5 m s-1) with no incline of the treadmill. At the end of the programme marked differences in cortical porosity and distribution of subperiosteal osteogenesis at the mid-shaft of the third metacarpal bone were found between the groups. Histomorphometrical examination of the dorsal cortex showed minimal bone remodelling in the exercised horses, but extensive modelling as evidenced by the large amount of subperiosteal bone formation. In contrast, the unexercised horses had significantly more bone remodelling and less formation of subperiosteal bone. The histomorphometric and microradiographic findings provided an explanation for changes in the non-invasive bone measurements that occurred during training. Bone mineral content of the mid-metacarpus was found to increase more in the exercised than the unexercised horses despite a lower overall growth in bodyweight. In those horses that completed the full training programme, ultrasound speed increased significantly by the end of the training programme. It remained unchanged in the horse that did not complete the full exercise programme and decreased slightly in the unexercised horses. The difference in ultrasound speed between the groups was considered to reflect differences in intracortical bone porosity, endosteal bone formation and alterations in skin thickness. The stiffness of cortical bone increased significantly in the exercised horses but remained unaltered in the unexercised horses

  13. Simulated weightlessness and synbiotic diet effects on rat bone mechanical strength

    Science.gov (United States)

    Sarper, Hüseyin; Blanton, Cynthia; DePalma, Jude; Melnykov, Igor V.; Gabaldón, Annette M.

    2014-10-01

    This paper reports results on exposure to simulated weightlessness that leads to a rapid decrease in bone mineral density known as spaceflight osteopenia by evaluating the effectiveness of dietary supplementation with synbiotics to counteract the effects of skeletal unloading. Forty adult male rats were studied under four different conditions in a 2 × 2 factorial design with main effects of diet (synbiotic and control) and weight condition (unloaded and control). Hindlimb unloading was performed at all times for 14 days followed by 14 days of recovery (reambulation). The synbiotic diet contained probiotic strains Lactobacillus acidophilus and Lactococcus lactis lactis and prebiotic fructooligosaccharide. This paper also reports on the development of a desktop three-point bending device to measure the mechanical strength of bones from rats subjected to simulated weightlessness. The importance of quantifying bone resistance to breakage is critical when examining the effectiveness of interventions against osteopenia resulting from skeletal unloading, such as astronauts experience, disuse or disease. Mechanical strength indices provide information beyond measures of bone density and microarchitecture that enhance the overall assessment of a treatment's potency. In this study we used a newly constructed three-point bending device to measure the mechanical strength of femur and tibia bones from hindlimb-unloaded rats fed an experimental synbiotic diet enriched with probiotics and fermentable fiber. Two calculated outputs for each sample were Young's modulus of elasticity and fracture stress. Bone major elements (calcium, magnesium, and phosphorous) were quantified using ICP-MS analysis. Hindlimb unloading was associated with a significant loss of strength in the femur, and with significant reductions in major bone elements. The synbiotic diet did not protect against these unloading effects. Tibia strength and major elements were not reduced by hindlimb unloading, as was

  14. Understanding heterogeneity in the effects of birth weight on adult cognition and wages.

    Science.gov (United States)

    Justin Cook, C; Fletcher, Jason M

    2015-05-01

    A large economics literature has shown long term impacts of birth weight on adult outcomes, including IQ and earnings that are often robust to sibling or twin fixed effects. We examine potential mechanisms underlying these effects by incorporating findings from the genetics and neuroscience literatures. We use a sample of siblings combined with an "orchids and dandelions hypothesis", where the IQ of genetic dandelions is not affected by in utero nutrition variation but genetic orchids thrive under advantageous conditions and wilt in poor conditions. Indeed, using variation in three candidate genes related to neuroplasticity (APOE, BDNF, and COMT), we find substantial heterogeneity in the associations between birth weight and adult outcomes, where part of the population (i.e., "dandelions") is not affected by birth weight variation. Our results help uncover why birth weight affects adult outcomes. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Effects of farm heterogeneity and methods for upscaling on modelled nitrogen losses in agricultural landscapes

    DEFF Research Database (Denmark)

    Dalgaard, Tommy; Hutchings, Nicholas John; Dragosits, U

    2011-01-01

    The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching......) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm...... to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20–30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N...

  16. Dynamic effective properties of heterogeneous geological formations with spherical inclusions under periodic time variations

    Science.gov (United States)

    Rabinovich, A.; Dagan, G.; Miloh, T.

    2013-04-01

    In unsteady groundwater flow (or similar processes of heat/electrical conduction), the heterogeneous medium structure is characterized by two random properties, the conductivity K and the specific storativity S. The average head field ⟨H ⟩and the associated effective properties Kef, Sef are determined for a layer with a periodic head drop between boundaries, such that H is periodic in time, and a medium made up of a matrix with a dilute concentration of spherical inclusions. In the common quasi-steady approximation, Kef is equal to the classical steady solution while Sef = SA, the arithmetic mean. We derive expressions for the frequency dependent Kef, Sef, which are generally complex, i.e., dynamic. The main result is the delineation of the ranges of the parameters: dimensionless frequency (ω) and contrasts of conductivity (κ) and storativity (s) between the matrix and the inclusions, for which dynamic effects are significant.

  17. Heterogeneous effects of oil shocks on exchange rates: evidence from a quantile regression approach.

    Science.gov (United States)

    Su, Xianfang; Zhu, Huiming; You, Wanhai; Ren, Yinghua

    2016-01-01

    The determinants of exchange rates have attracted considerable attention among researchers over the past several decades. Most studies, however, ignore the possibility that the impact of oil shocks on exchange rates could vary across the exchange rate returns distribution. We employ a quantile regression approach to address this issue. Our results indicate that the effect of oil shocks on exchange rates is heterogeneous across quantiles. A large US depreciation or appreciation tends to heighten the effects of oil shocks on exchange rate returns. Positive oil demand shocks lead to appreciation pressures in oil-exporting countries and this result is robust across lower and upper return distributions. These results offer rich and useful information for investors and decision-makers.

  18. Effects of solution viscosity on heterogeneous electron transfer across a liquid/liquid interface

    Energy Technology Data Exchange (ETDEWEB)

    Bai Yamin; Sun Peng; Zhang Meiqin; Gao Zhao; Yang Zhengyu; Shao Yuanhua

    2003-10-15

    Scanning electrochemical microscopy (SECM) is employed to investigate the effect of solution viscosity on the rate constants of electron transfer (ET) reaction between potassium ferricyanide in water and 7,7,8,8-tetracyanoquinodimethane (TCNQ) in 1,2-dichloroethane. Either tetrabutylammonium (TBA{sup +}) or ClO{sub 4}{sup -} is chosen as the common ion in both phases to control the interfacial potential drop. The rate constant of heterogeneous ET reaction between TCNQ and ferrocyanide produced in-situ, k{sub 12}, is evaluated by SECM and is inversely proportional to the viscosity of the aqueous solution and directly proportional to the diffusion coefficient of K{sub 4}Fe(CN){sub 6} in water when the concentration of TCNQ in the DCE phase is in excess. The k{sub 12} dependence on viscosity is explained in terms of the longitudinal relaxation time of the solution. The rate constant of the heterogeneous ET reaction between TCNQ{sup -} and ferricyanide, k{sub 21}, is also obtained by SECM and these results cannot be explained by the same manner.

  19. Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2016-03-01

    Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

  20. Modeling triple-negative breast cancer heterogeneity: effects of stromal macrophages, fibroblasts and tumor vasculature.

    Science.gov (United States)

    Norton, Kerri-Ann; Jin, Kideok; Popel, Aleksander S

    2018-05-08

    A hallmark of breast tumors is its spatial heterogeneity that includes its distribution of cancer stem cells and progenitor cells, but also heterogeneity in the tumor microenvironment. In this study we focus on the contributions of stromal cells, specifically macrophages, fibroblasts, and endothelial cells on tumor progression. We develop a computational model of triple-negative breast cancer based on our previous work and expand it to include macrophage infiltration, fibroblasts, and angiogenesis. In vitro studies have shown that the secretomes of tumor-educated macrophages and fibroblasts increase both the migration and proliferation rates of triple-negative breast cancer cells. In vivo studies also demonstrated that blocking signaling of selected secreted factors inhibits tumor growth and metastasis in mouse xenograft models. We investigate the influences of increased migration and proliferation rates on tumor growth, the effect of the presence on fibroblasts or macrophages on growth and morphology, and the contributions of macrophage infiltration on tumor growth. We find that while the presence of macrophages increases overall tumor growth, the increase in macrophage infiltration does not substantially increase tumor growth and can even stifle tumor growth at excessive rates. Copyright © 2018. Published by Elsevier Ltd.

  1. Effects of ionization chamber construction on dose measurements in a heterogeneity

    International Nuclear Information System (INIS)

    Mauceri, T.; Kase, K.

    1987-01-01

    Traditionally, measurements have been made in heterogeneous phantoms to determine the factors which should be applied to dose calculations, when calculating a dose to a heterogeneous medium. Almost all measurements have relied on relatively thin-walled ion chambers, with no attempt to match ion chamber wall material to the measuring medium. The recent AAPM dosimetry protocol has established that a mismatch between ion chamber wall and phantom material can have an effect on dose measurement. To investigate the affect of this mismatch of ion chamber wall material to phantom material, two parallel-plate ion chambers were constructed. One ion chamber from solid water, for measurements in a solid water phantom and the other from plastic lung material, for measurements in a plastic lung material phantom. Correction factors measured by matching ion chamber to media were compared to correction factors measured by using a thin-walled cavity ion chamber with no regard for matching wall and media for cobalt-60, 6-, 10- and 20-MV photon beams. The results demonstrated that the matching of ion chamber to measuring media can be ignored, provided that a small, approximately tissue-equivalent, thin-walled ion chamber is used for measuring the correction factors

  2. Effects of radiation on the developing dentition and supporting bone

    International Nuclear Information System (INIS)

    Carl, W.; Wood, R.

    1980-01-01

    Underdevelopment of teeth after exposure to radiation has been observed since the early experiments with x rays. Two patients had been irradiated at young ages for embryonal rhabdomyosarcomas. For the patient treated with radiation at age 4 for a lesion in the submandibular area, root development of the mandibular teeth stopped, but the teeth nevertheless erupted. In the patient treated with radiation at age 9 for a tumor in the left cheek, bone apposition in the left side of the mandible failed to continue at the same rate as on the right side. Although new megavoltage radiation machines have reduced the chances of bone complications in adults, developing bone and structures are still significantly affected by radiation

  3. [Effects of growth hormone replacement therapy on bone metabolism].

    Science.gov (United States)

    Yamamoto, Masahiro; Sugimoto, Toshitsugu

    2014-06-01

    Growth hormone (GH) as well as insulin like growth factor-1 (IGF-1) are essential hormones to maintain homeostasis of bone turnover by activating osteoblastogenesis and osteoclastogenesis. Results from GH replacement therapy for primary osteoporosis and adult-onset GH deficiency (AGHD) suggest that one year or more treatment period by this agent is required to gain bone mineral density (BMD) over the basal level after compensating BMD loss caused by dominant increase in bone resorption which was observed at early phase of GH treatment. A recent meta-analysis demonstrates the efficacy of GH replacement therapy on increases in BMD in male patients with AGHD. Additional analyses are needed to draw firm conclusions in female patients with AGHD, because insufficient amounts of GH might be administrated to them without considerations of influence of estrogen replacement therapy on IGF-1 production. Further observational studies are needed to clarify whether GH replacement therapy prevent fracture risk in these patients.

  4. Mixing effects on apparent reaction rates and isotope fractionation during denitrification in a heterogeneous aquifer

    Science.gov (United States)

    Green, Christopher T.; Böhlke, John Karl; Bekins, Barbara A.; Phillips, Steven P.

    2010-01-01

    Gradients in contaminant concentrations and isotopic compositions commonly are used to derive reaction parameters for natural attenuation in aquifers. Differences between field‐scale (apparent) estimated reaction rates and isotopic fractionations and local‐scale (intrinsic) effects are poorly understood for complex natural systems. For a heterogeneous alluvial fan aquifer, numerical models and field observations were used to study the effects of physical heterogeneity on reaction parameter estimates. Field measurements included major ions, age tracers, stable isotopes, and dissolved gases. Parameters were estimated for the O2 reduction rate, denitrification rate, O2 threshold for denitrification, and stable N isotope fractionation during denitrification. For multiple geostatistical realizations of the aquifer, inverse modeling was used to establish reactive transport simulations that were consistent with field observations and served as a basis for numerical experiments to compare sample‐based estimates of “apparent” parameters with “true“ (intrinsic) values. For this aquifer, non‐Gaussian dispersion reduced the magnitudes of apparent reaction rates and isotope fractionations to a greater extent than Gaussian mixing alone. Apparent and true rate constants and fractionation parameters can differ by an order of magnitude or more, especially for samples subject to slow transport, long travel times, or rapid reactions. The effect of mixing on apparent N isotope fractionation potentially explains differences between previous laboratory and field estimates. Similarly, predicted effects on apparent O2threshold values for denitrification are consistent with previous reports of higher values in aquifers than in the laboratory. These results show that hydrogeological complexity substantially influences the interpretation and prediction of reactive transport.

  5. Evidence for the Adverse Effect of Starvation on Bone Quality: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    Janina Kueper

    2015-01-01

    Full Text Available Malnutrition and starvation’s possible adverse impacts on bone health and bone quality first came into the spotlight after the horrors of the Holocaust and the ghettos of World War II. Famine and food restrictions led to a mean caloric intake of 200–800 calories a day in the ghettos and concentration camps, resulting in catabolysis and starvation of the inhabitants and prisoners. Severely increased risks of fracture, poor bone mineral density, and decreased cortical strength were noted in several case series and descriptive reports addressing the medical issues of these individuals. A severe effect of severely diminished food intake and frequently concomitant calcium- and Vitamin D deficiencies was subsequently proven in both animal models and the most common cause of starvation in developed countries is anorexia nervosa. This review attempts to summarize the literature available on the impact of the metabolic response to Starvation on overall bone health and bone quality.

  6. Evidence for the adverse effect of starvation on bone quality: a review of the literature.

    Science.gov (United States)

    Kueper, Janina; Beyth, Shaul; Liebergall, Meir; Kaplan, Leon; Schroeder, Josh E

    2015-01-01

    Malnutrition and starvation's possible adverse impacts on bone health and bone quality first came into the spotlight after the horrors of the Holocaust and the ghettos of World War II. Famine and food restrictions led to a mean caloric intake of 200-800 calories a day in the ghettos and concentration camps, resulting in catabolysis and starvation of the inhabitants and prisoners. Severely increased risks of fracture, poor bone mineral density, and decreased cortical strength were noted in several case series and descriptive reports addressing the medical issues of these individuals. A severe effect of severely diminished food intake and frequently concomitant calcium- and Vitamin D deficiencies was subsequently proven in both animal models and the most common cause of starvation in developed countries is anorexia nervosa. This review attempts to summarize the literature available on the impact of the metabolic response to Starvation on overall bone health and bone quality.

  7. A review of the effects of dietary silicon intake on bone homeostasis and regeneration.

    Science.gov (United States)

    Rodella, L F; Bonazza, V; Labanca, M; Lonati, C; Rezzani, R

    2014-11-01

    Increasing evidences suggest that dietary Silicon (Si) intake, is positively correlated with bone homeostasis and regeneration, representing a potential and valid support for the prevention and improvement of bone diseases, like osteoporosis. This review, aims to provide the state of art of the studies performed until today, in order to investigate and clarify the beneficial properties and effects of silicates, on bone metabolism. We conducted a systematic literature search up to March 2013, using two medical databases (Pubmed and the Cochrane Library), to review the studies about Si consumption and bone metabolism. We found 45 articles, but 38 were specifically focused on Si studies. RESULTS showed a positive relationship between dietary Si intake and bone regeneration.

  8. Effect of a carbonated HAP/β-glucan composite bone substitute on healing of drilled bone voids in the proximal tibial metaphysis of rabbits

    International Nuclear Information System (INIS)

    Borkowski, Leszek; Pawłowska, Marta; Radzki, Radosław P.; Bieńko, Marek; Polkowska, Izabela; Belcarz, Anna; Karpiński, Mirosław; Słowik, Tymoteusz; Matuszewski, Łukasz; Ślósarczyk, Anna; Ginalska, Grażyna

    2015-01-01

    A novel elastic hydroxyapatite-based composite of high surgical handiness has been developed. Its potential application in orthopedics as a filler of bone defects has been studied. The biomaterial was composed of carbonated hydroxyapatite (CHAP) granules and polysaccharide polymer (β-1,3-glucan). Cylinders of 4 mm in diameter and 6 mm in length were implanted into bone cavities created in the proximal metaphysis of tibiae of 24 New Zealand white rabbits. 18 sham-operated animals were used as controls. After 1, 3 or 6 months, the rabbits were euthanized, the bones were harvested and subjected to analysis. Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. Peripheral quantitative computed tomography (pQCT) indicated the stimulating effect of the biomaterial on bone formation and mineralization. Densitometry (DXA) analysis suggested that biomineralization of bones was preceded by bioresorption and gradual disappearance of porous ceramic granules. The findings suggest that the CHAP–glucan composite material enables regeneration of bone tissue and could serve as a bone defect filler. - Highlights: • Highly porous carbonate HAP granules and β-1,3-glucan were used to fill bone voids. • Critical size defects of rabbit tibiae were filled with the composite scaffolds. • Biocompatibility, mineralization and osseointegration of implants were examined. • Histological analysis indicated a high biocompatibility of composite grafts. • We report penetration of bony tissue into implants and advanced osseointegration

  9. Effect of a carbonated HAP/β-glucan composite bone substitute on healing of drilled bone voids in the proximal tibial metaphysis of rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Borkowski, Leszek, E-mail: leszek.borkowski@umlub.pl [Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Pawłowska, Marta; Radzki, Radosław P.; Bieńko, Marek [Department of Animal Physiology, University of Life Sciences in Lublin, Akademicka 12, 20-033 Lublin (Poland); Polkowska, Izabela [Department and Clinic of Animal Surgery, University of Life Sciences in Lublin, Głęboka 30, 20-612 Lublin (Poland); Belcarz, Anna [Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland); Karpiński, Mirosław [Department of Companion and Wildlife Animals, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin (Poland); Słowik, Tymoteusz [Independent Radiology Unit at Lublin Small Animals Medical Centre, Stefczyka 11, 20-151 Lublin (Poland); Matuszewski, Łukasz [Children' s Orthopaedic Clinic and Rehabilitation Department, Medical University of Lublin, Chodzki 2, 20-093 Lublin (Poland); Ślósarczyk, Anna [Faculty of Materials Science and Ceramics, AGH-University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland); Ginalska, Grażyna [Department of Biochemistry and Biotechnology, Medical University of Lublin, Chodźki 1, 20-093 Lublin (Poland)

    2015-08-01

    A novel elastic hydroxyapatite-based composite of high surgical handiness has been developed. Its potential application in orthopedics as a filler of bone defects has been studied. The biomaterial was composed of carbonated hydroxyapatite (CHAP) granules and polysaccharide polymer (β-1,3-glucan). Cylinders of 4 mm in diameter and 6 mm in length were implanted into bone cavities created in the proximal metaphysis of tibiae of 24 New Zealand white rabbits. 18 sham-operated animals were used as controls. After 1, 3 or 6 months, the rabbits were euthanized, the bones were harvested and subjected to analysis. Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. Peripheral quantitative computed tomography (pQCT) indicated the stimulating effect of the biomaterial on bone formation and mineralization. Densitometry (DXA) analysis suggested that biomineralization of bones was preceded by bioresorption and gradual disappearance of porous ceramic granules. The findings suggest that the CHAP–glucan composite material enables regeneration of bone tissue and could serve as a bone defect filler. - Highlights: • Highly porous carbonate HAP granules and β-1,3-glucan were used to fill bone voids. • Critical size defects of rabbit tibiae were filled with the composite scaffolds. • Biocompatibility, mineralization and osseointegration of implants were examined. • Histological analysis indicated a high biocompatibility of composite grafts. • We report penetration of bony tissue into implants and advanced osseointegration.

  10. The Effect of Spaceflight on Bone Cell Cultures

    Science.gov (United States)

    Landis, William J.

    1999-01-01

    Understanding the response of bone to mechanical loading (unloading) is extremely important in defining the means of adaptation of the body to a variety of environmental conditions such as during heightened physical activity or in extended explorations of space or the sea floor. The mechanisms of the adaptive response of bone are not well defined, but undoubtedly they involve changes occurring at the cellular level of bone structure. This proposal has intended to examine the hypothesis that the loading (unloading) response of bone is mediated by specific cells through modifications of their activity cytoskeletal elements, and/or elaboration of their extracellular matrices. For this purpose, this laboratory has utilized the results of a number of previous studies defining molecular biological, biochemical, morphological, and ultrastructural events of the reproducible mineralization of a primary bone cell (osteoblast) culture system under normal loading (1G gravity level). These data and the culture system then were examined following the use of the cultures in two NASA shuttle flights, STS-59 and STS-63. The cells collected from each of the flights were compared to respective synchronous ground (1G) control cells examined as the flight samples were simultaneously analyzed and to other control cells maintained at 1G until the time of shuttle launch, at which point they were terminated and studied (defined as basal cells). Each of the cell cultures was assayed in terms of metabolic markers- gene expression; synthesis and secretion of collagen and non-collagenous proteins, including certain cytoskeletal components; assembly of collagen into macrostructural arrays- formation of mineral; and interaction of collagen and mineral crystals during calcification of the cultures. The work has utilized a combination of biochemical techniques (radiolabeling, electrophoresis, fluorography, Western and Northern Blotting, and light microscopic immunofluorescence) and structural

  11. Effect of the wavelength on laser induced breakdown spectrometric analysis of archaeological bone

    Energy Technology Data Exchange (ETDEWEB)

    Kasem, M.A. [National Institute of Laser Enhanced Science (NILES), Cairo University, Giza (Egypt); Gonzalez, J.J.; Russo, R.E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Harith, M.A., E-mail: mharithm@niles.edu.eg [National Institute of Laser Enhanced Science (NILES), Cairo University, Giza (Egypt)

    2014-11-01

    The analytical exploitation of the laser induced plasma suffers from its transient behavior due to some nonlinear effects. These phenomena are matrix-dependent and limit the use of LIBS to mostly semi-quantitative precision. The plasma parameters have to be kept as constant as possible during LIBS measurements. Studying archaeological bone samples using LIBS technique could be more difficult since these samples are less tough in their texture than many other solid samples. Thus, the ablation process could change the sample morphological features rapidly resulting in poor reproducibility and statistics. Furthermore archaeological bones are subjected to diagenesis effects due to burial environment and postmortem effects. In the present work comparative analytical study of UV (266 nm) and IR (1064 nm) LIBS for archaeological bone samples belonging to four ancient Egyptian dynasties representing the middle kingdom (1980–1630 BC), 2nd intermediate period (1630–1539/23 BC), Roman–Greek period (30 BC–A.D. 395) and the late period (664–332 BC). Measurements have been performed under identical experimental conditions except the laser wavelength to examine its effects. Elemental fluctuations within the same dynasty were studied for reliable information about each dynasty. The analytical results demonstrated that UV-LIBS gives a more realistic picture for bone elemental composition within the same dynasty, and bone ash could be more suitable as a reference material for bone calibration in the case of UV-LIBS. - Highlights: • UV and IR LIBS for archaeological bone samples have been performed. • Elemental fluctuations within the same dynasty were studied. • UV-LIBS gave realistic picture for bone elemental composition for the same dynasty. • Depth profile for Sr/Ca concentration was an indicator for the diagenesis effect. • Bone ash is the most suitable for calcified tissue calibration for UV-LIBS.

  12. Effect of the wavelength on laser induced breakdown spectrometric analysis of archaeological bone

    International Nuclear Information System (INIS)

    Kasem, M.A.; Gonzalez, J.J.; Russo, R.E.; Harith, M.A.

    2014-01-01

    The analytical exploitation of the laser induced plasma suffers from its transient behavior due to some nonlinear effects. These phenomena are matrix-dependent and limit the use of LIBS to mostly semi-quantitative precision. The plasma parameters have to be kept as constant as possible during LIBS measurements. Studying archaeological bone samples using LIBS technique could be more difficult since these samples are less tough in their texture than many other solid samples. Thus, the ablation process could change the sample morphological features rapidly resulting in poor reproducibility and statistics. Furthermore archaeological bones are subjected to diagenesis effects due to burial environment and postmortem effects. In the present work comparative analytical study of UV (266 nm) and IR (1064 nm) LIBS for archaeological bone samples belonging to four ancient Egyptian dynasties representing the middle kingdom (1980–1630 BC), 2nd intermediate period (1630–1539/23 BC), Roman–Greek period (30 BC–A.D. 395) and the late period (664–332 BC). Measurements have been performed under identical experimental conditions except the laser wavelength to examine its effects. Elemental fluctuations within the same dynasty were studied for reliable information about each dynasty. The analytical results demonstrated that UV-LIBS gives a more realistic picture for bone elemental composition within the same dynasty, and bone ash could be more suitable as a reference material for bone calibration in the case of UV-LIBS. - Highlights: • UV and IR LIBS for archaeological bone samples have been performed. • Elemental fluctuations within the same dynasty were studied. • UV-LIBS gave realistic picture for bone elemental composition for the same dynasty. • Depth profile for Sr/Ca concentration was an indicator for the diagenesis effect. • Bone ash is the most suitable for calcified tissue calibration for UV-LIBS

  13. The Effect of Rosiglitazone on Bone Quality in a Rat Model of Insulin Resistance and Osteoporosis

    Science.gov (United States)

    Sardone, Laura Donata

    Rosiglitazone (RSG) is an insulin-sensitizing drug used to treat Type 2 Diabetes Mellitus (T2DM). Clinical trials show that women taking RSG experience more limb fractures than patients taking other T2DM drugs. The purpose of this study is to understand how RSG (3mg/kg/day and 10mg/kg/day) and the bisphosphonate alendronate (0.7mg/kg/week) alter bone quality in the male, female and female ovariectomized (OVX) Zucker fatty rat model over a 12 week period. Bone quality was evaluated by mechanical testing of cortical and trabecular bone. Microarchitecture, bone mineral density (BMD), cortical bone porosity, bone formation/resorption and mineralization were also measured. Female OVX RSG10mg/kg rats had significantly lower vertebral BMD and compromised trabecular architecture versus OVX controls. Increased cortical porosity and decreased mechanical properties occurred in these rats. ALN treatment prevented these negative effects in the OVX RSG model. Evidence of reduced bone formation and excess bone resorption was detected in female RSG-treated rats.

  14. Effect of odanacatib on root resorption and alveolar bone metabolism during orthodontic tooth movement.

    Science.gov (United States)

    Wei, X X; Chu, J P; Zou, Y Z; Ru, N; Cui, S X; Bai, Y X

    2015-12-22

    The aim of this study was to investigate the effect of local administration of odanacatib (ODN) on orthodontic root resorption and the status of alveolar bone metabolism in rat molars. All specimens were scanned using microcomputed tomography and then the raw images were reconstructed. The total volume of the root resorption craters of the 60 g-NS (normal saline) group was higher than in the 60 g-ODN group and the control group. In the 60 g-NS group, the bone volume fraction values of alveolar bone were significantly decreased compared with the other 2 groups. There were no significant differences in the bone volume fraction values of the tibiae among the 3 groups. The results of tartrate-resistant acid phosphatase-positive (TRAP+) numbers showed that there was no difference between the 60 g-NS group and the 60 g-ODN group. The expression of cathepsin K was decreased significantly in the 60 g-ODN group. These results indicate that ODN reduces orthodontics-induced external root resorption and increases alveolar bone metabolism. This may be because ODN inhibits the activity of odontoclasts, but maintains the quantity of odontoclasts and enhances bone formation. ODN promotes local alveolar bone metabolism, but does not affect systemic bone metabolism.

  15. The Effect of Combined Exercise on Bone Mineral Density of Premenopausal Females

    Directory of Open Access Journals (Sweden)

    Safoura Ghasemi

    2016-06-01

    Full Text Available Background and Objectives: The best way to prevent osteoporosis, at old age is to prevent bone loss and at young age is trying to keep bones healthy, therefore the aim of this study was to determine the effect of combined exercise on bone mineral density of premenopausal females. Materials and Methods: This semi-experimental study was conducted among 20 premenopausal females between 40 and 45 years old, which were randomly assigned to two groups (experimental and control groups in Hamadan city, during year 2016. The experimental group completed a 12-week combined exercise-training program (6 weeks in water and 6 weeks on land, three times a week and 70 minutes per session. Before and after the 12 weeks, femoral bone mineral density in all samples was measured by DEXA bone mineral densitometry. Data were analyzed with the SPSS 21 software using descriptive and inferential statistics, such as independent and paired t-test, and Analysis of Covariance (ANCOVA. Results: Bone mineral density of femoral neck and total hip of the experimental group, had significant differences with corresponding areas of the control group (P <0.05. In other words, the results revealed that 12 weeks of combined exercise increases femoral bone mineral density in the experimental group with a significant decrease in the control group. Conclusions: According to the results, to prevent a decrease in bone mineral density during the menopausal period, combined exercises are recommended for females at this age.

  16. High doses of ionizing radiation on bone repair: is there effect outside the irradiated site?

    Science.gov (United States)

    Rocha, Flaviana Soares; Dias, Pâmella Coelho; Limirio, Pedro Henrique Justino Oliveira; Lara, Vitor Carvalho; Batista, Jonas Dantas; Dechichi, Paula

    2017-03-01

    Local ionizing radiation causes damage to bone metabolism, it reduces blood supply and cellularity over time. Recent studies indicate that radiation promotes biological response outside the treatment field. The aim of this study was to investigate the effects of ionizing radiation on bone repair outside the irradiated field. Ten healthy male Wistar rats were used; and five animals were submitted to radiotherapy on the left femur. After 4 weeks, in all animals were created bone defects in the right and left femurs. Seven days after surgery, animals were euthanized. The femurs were removed and randomly divided into 3 groups (n=5): Control (C) (right femur of the non-irradiated animals); Local ionizing radiation (IR) (left femur of the irradiated animals); Contralateral ionizing radiation (CIR) (right femur of the irradiated animals). The femurs were processed and embedded in paraffin; and bone histologic sections were evaluated to quantify the bone neoformation. Histomorphometric analysis showed that there was no significant difference between groups C (24.6±7.04) and CIR (25.3±4.31); and IR group not showed bone neoformation. The results suggest that ionizing radiation affects bone repair, but does not interfere in bone repair distant from the primary irradiated site. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. An improved cost-effective, reproducible method for evaluation of bone loss in a rodent model.

    Science.gov (United States)

    Fine, Daniel H; Schreiner, Helen; Nasri-Heir, Cibele; Greenberg, Barbara; Jiang, Shuying; Markowitz, Kenneth; Furgang, David

    2009-02-01

    This study was designed to investigate the utility of two "new" definitions for assessment of bone loss in a rodent model of periodontitis. Eighteen rats were divided into three groups. Group 1 was infected by Aggregatibacter actinomycetemcomitans (Aa), group 2 was infected with an Aa leukotoxin knock-out, and group 3 received no Aa (controls). Microbial sampling and antibody titres were determined. Initially, two examiners measured the distance from the cemento-enamel-junction to alveolar bone crest using the three following methods; (1) total area of bone loss by radiograph, (2) linear bone loss by radiograph, (3) a direct visual measurement (DVM) of horizontal bone loss. Two "new" definitions were adopted; (1) any site in infected animals showing bone loss >2 standard deviations above the mean seen at that site in control animals was recorded as bone loss, (2) any animal with two or more sites in any quadrant affected by bone loss was considered as diseased. Using the "new" definitions both evaluators independently found that infected animals had significantly more disease than controls (DVM system; p<0.05). The DVM method provides a simple, cost effective, and reproducible method for studying periodontal disease in rodents.

  18. On-Command Exoskeleton for Countermeasure Microgravity Effects on Muscles and Bones

    Science.gov (United States)

    Bar-Cohen, Y.; Bao, X.; Badescu, M.; Sherrit, S.; Mavroidis, C.; Unluhisarcikh, O.; Pietrusinski, M.; Rajulu, S.; Berka, R.; Cowley, M.

    2012-06-01

    On-command exoskeleton with impeding and augmenting elements would support the operation of astronauts traveling to Mars. Thus, countermeasure deleterious effects on the muscles and bones during travel and assist their physical activity on Mars.

  19. High-Phosphorus, Low-Calcium Dietary Intakes and Bone Effects of Physical Training

    National Research Council Canada - National Science Library

    Zerath, Erik

    2003-01-01

    .... Diet inquiries showed changes in calcium and phosphorus intakes. This study is aimed at investigating the effects of physical activity on bone tissue in the context of high-phosphorus and low-calcium intakes. Sedentary (SED) and trained (TR...

  20. Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects.

    LENUS (Irish Health Repository)

    Mohamed, Seif

    2010-05-01

    This study was designed to evaluate the effect of surface contamination on osseointegration of dental implants surrounded by a circumferential bone defect and to compare osseointegration around Osseotite with that around Nanotite implants.

  1. Protective Effects of Vildagliptin against Pioglitazone-Induced Bone Loss in Type 2 Diabetic Rats.

    Science.gov (United States)

    Eom, Young Sil; Gwon, A-Ryeong; Kwak, Kyung Min; Kim, Ju-Young; Yu, Seung Hee; Lee, Sihoon; Kim, Yeun Sun; Park, Ie Byung; Kim, Kwang-Won; Lee, Kiyoung; Kim, Byung-Joon

    2016-01-01

    Long-term use of thiazolidinediones (TZDs) is associated with bone loss and an increased risk of fracture in patients with type 2 diabetes (T2DM). Incretin-based drugs (glucagon-like peptide-1 (GLP-1) agonists and dipeptidylpeptidase-4 (DPP-4) inhibitors) have several benefits in many systems in addition to glycemic control. In a previous study, we reported that exendin-4 might increase bone mineral density (BMD) by decreasing the expression of SOST/sclerostin in osteocytes in a T2DM animal model. In this study, we investigated the effects of a DPP-4 inhibitor on TZD-induced bone loss in a T2DM animal model. We randomly divided 12-week-old male Zucker Diabetic Fatty (ZDF) rats into four groups; control, vildagliptin, pioglitazone, and vildagliptin and pioglitazone combination. Animals in each group received the respective treatments for 5 weeks. We performed an intraperitoneal glucose tolerance test (IPGTT) before and after treatment. BMD and the trabecular micro-architecture were measured by DEXA and micro CT, respectively, at the end of the treatment. The circulating levels of active GLP-1, bone turnover markers, and sclerostin were assayed. Vildagliptin treatment significantly increased BMD and trabecular bone volume. The combination therapy restored BMD, trabecular bone volume, and trabecular bone thickness that were decreased by pioglitazone. The levels of the bone formation marker, osteocalcin, decreased and that of the bone resorption marker, tartrate-resistant acid phosphatase (TRAP) 5b increased in the pioglitazone group. These biomarkers were ameliorated and the pioglitazone-induced increase in sclerostin level was lowered to control values by the addition of vildagliptin. In conclusion, our results indicate that orally administered vildagliptin demonstrated a protective effect on pioglitazone-induced bone loss in a type 2 diabetic rat model.

  2. Effects of amlodipine on bone metabolism in male albino Wistar rats

    Directory of Open Access Journals (Sweden)

    Iveta Gradošová

    2011-01-01

    Full Text Available Amlodipine (dihydropyridine-type calcium channel blocker is a widely used agent for the treatment of hypertension in human and veterinary medicine but detailed information about its effects on bone metabolism are missing. Therefore, the aim of our study was to investigate the effect of amlodipine on bone metabolism in male albino Wistar rats. Amlodipine (0.3 mg/100 g body weight; gavage was administered to 8 rats for 8 weeks. Control group (n = 8 received aqua pro inj. (0.2 ml/100 g body weight; gavage. Bone marker concentrations of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I and aminoterminal propeptide of procollagen type I in serum, and of bone alkaline phosphatase (BALP in both serum and bone homogenate were measured by enzyme immunoassay. We investigated the expression of bone morphogenetic protein 2 (BMP-2 in proximal tibia using Western blotting, and bone mineral density was measured by Dual-energy X-ray Absorptiometry in lumbar and caudal vertebrae and in femoral areas. Mechanical properties of the femurs were measured by three-point bending of the shaft and compression testing of the femoral neck. After 8 weeks of amlodipine administration there was a significant decrease in serum concentrations of BALP (p = 0.0009 and CTX-I (p = 0.003, and the content of BALP in bone homogenate (p = 0.026 compared to the control. In addition, Western blot analysis indicated increased BMP-2 protein concentration after amlodipine administration. Our findings suggest that amlodipine has a retarding influence on bone metabolism in rats by decreasing bone turnover, which probably in consequence increases expression of BMP-2.

  3. Heterogeneous effects of M-CSF isoforms on the progression of MLL-AF9 leukemia.

    Science.gov (United States)

    Wang, Rong; Feng, Wenli; Yang, Feifei; Yang, Xiao; Wang, Lina; Chen, Chong; Hu, Yuting; Ren, Qian; Zheng, Guoguang

    2018-02-01

    Macrophage colony-stimulating factor (M-CSF) regulates both malignant cells and microenvironmental cells. Its splicing isoforms show functional heterogeneity. However, their roles on leukemia have not been well established. Here, the expression of total M-CSF in patients with hematopoietic malignancies was analyzed. The roles of M-CSF isoforms on the progression of acute myeloid leukemia (AML) were studied by establishing MLL-AF9-induced mouse AML models with high level membrane-bound M-CSF (mM-CSF) or soluble M-CSF (sM-CSF). Total M-CSF was highly expressed in myeloid leukemia patients. Furthermore, mM-CSF but not sM-CSF prolonged the survival of leukemia mice. While sM-CSF was more potent to promote proliferation and self-renew, mM-CSF was more potent to promote differentiation. Moreover, isoforms had different effects on leukemia-associated macrophages (LAMs) though they both increase monocytes/macrophages by growth-promoting and recruitment effects. In addition, mM-CSF promoted specific phagocytosis of leukemia cells by LAMs. RNA-seq analysis revealed that mM-CSF enhanced phagocytosis-associated genes and activated oxidative phosphorylation and metabolism pathway. These results highlight heterogeneous effects of M-CSF isoforms on AML progression and the mechanisms of mM-CSF, that is, intrinsically promoting AML cell differentiation and extrinsically enhancing infiltration of macrophages and phagocytosis by macrophages, which may provide potential clues for clinical diagnosis and therapy. © 2017 Australasian Society for Immunology Inc.

  4. Subpopulations of Bone Marrow Mesenchymal Stem Cells Exhibit Differential Effects in Delaying Retinal Degeneration.

    Science.gov (United States)

    Li, P; Tian, H; Li, Z; Wang, L; Gao, F; Ou, Q; Lian, C; Li, W; Jin, C; Zhang, J; Xu, J-Y; Wang, J; Zhang, J; Wang, F; Lu, L; Xu, G-T

    2016-01-01

    Bone marrow mesenchymal stem cells (BMSCs) have a therapeutic role in retinal degeneration (RD). However, heterogeneity of BMSCs may be associated with differential therapeutic effects in RD. In order to confirm this hypothesis, two subsets of rat BMSCs, termed rBMSC1 and rBMSC2, were obtained, characterized and functionally evaluated in the treatment of RD of Royal College of Surgeons (RCS) rats. Both subpopulations expressed mesenchymal stem cells (MSC) markers CD29 and CD90, but were negative for hemacyte antigen CD11b and CD45 expression. In comparison with rBMSC2, rBMSC1 showed higher rate of proliferation, stronger colony formation, and increased adipogenic potential, whereas rBMSC2 exhibited higher osteogenic potential. Microarray analysis showed differential gene expression patterns between rBMSC1 and rBMSC2, including functions related to proliferation, differentiation, immunoregulation, stem cell maintenance and division, survival and antiapoptosis. After subretinal transplantation in RCS rats, rBMSC1 showed stronger rescue effect than rBMSC2, including increased b-wave amplitude, restored retinal nuclear layer thickness, and decreased number of apoptotic photoreceptors, whereas the rescue function of rBMSC2 was essentially not better than the control. Histological analysis also demonstrated that rBMSC1 possessed a higher survival rate than rBMSC2 in subretinal space. In addition, treatment of basic fibroblast growth factor, an accompanying event in subretinal injection, triggered more robust increase in secretion of growth factors by rBMSC1 as compared to rBMSC2. Taken together, these results have suggested that the different therapeutic functions of BMSC subpopulations are attributed to their distinct survival capabilities and paracrine functions. The underlying mechanisms responsible for the different functions of BMSC subpopulation may lead to a new strategy for the treatment of RD.

  5. Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-14-2-0190 TITLE: Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone PRINCIPAL...including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing...29 Sep 2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Testosterone Combined with Electrical Stimulation and Standing: Effect on Muscle and Bone 5b

  6. Biochemical and biophysical aspects of iation effects in bone tissues at different stages of ontogenesis

    International Nuclear Information System (INIS)

    Frenkel', L.A.

    1986-01-01

    In experiments on rats it has been ascertained that under the effect of X radiation in the dose 8Gy already at early stages of organism affection in the mineral spectrum of bone tissue considerable disturbances take place, the character and degree of which depend on the animal age. Microelement composition of bone tissue under conditions of acute radiation effect undergo significant changes. The degree and character of the changes depend on radiation affection dynamics and age of the experimental animals

  7. The effects of bone on proton NMR relaxation times of surrounding liquids

    Science.gov (United States)

    Davis, C. A.; Genant, H. K.; Dunham, J. S.

    1986-01-01

    Preliminary attempts by our group at UCSF to assess fat content of vertebral marrow in the lumbar spine using relaxation time information demonstrated that the presence of trabecular bone affects relaxation times. The objective of this work was a thorough study of the effects of bone on NMR relaxation characteristics of surrounding liquids. Trabecular bone from autopsy specimens was ground up and sifted into a series of powders with graded densities ranging from 0.3 gm/cc to 0.8 gm/cc. Each powder was placed first in n-saline and then in cottonseed oil. With spectroscopy, spin-lattice relaxation times (T1) and effective spin-spin relaxation times (T2*) were measured for each liquid in each bone powder. As bone density and surface to volume ratio increased, T1 decreased faster for saline than for oil. T2* decreased significantly for both water and oil as the surface to volume ratio increased. It was concluded that effects of water on T1 could be explained by a surface interaction at the bone/liquid interface, which restricted rotational and translational motion of nearby molecules. The T1s of oil were not affected since oil molecules are nonpolar, do not participate in significant intermolecular hydrogen bonding, and therefore would not be expected to interact strongly with the bone surface. Effects on T2* could be explained by local magnetic field inhomogeneities created by discontinuous magnetic susceptibility near the bone surface. These preliminary results suggest that water in contact with trabecular bone in vivo will exhibit shortened relaxation times.

  8. The proteomic dataset for bone marrow derived human mesenchymal stromal cells: Effect of in vitro passaging

    Directory of Open Access Journals (Sweden)

    Samuel T. Mindaye

    2015-12-01

    Full Text Available Bone-marrow derived mesenchymal stromal cells (BMSCs have been in clinical trials for therapy. One major bottleneck in the advancement of BMSC-based products is the challenge associated with cell isolation, characterization, and ensuring cell fitness over the course of in vitro cell propagation steps. The data in this report is part of publications that explored the proteomic changes following in vitro passaging of BMSCs [4] and the molecular heterogeneity in cultures obtained from different human donors [5,6].The methodological details involving cell manufacturing, proteome harvesting, protein identification and quantification as well as the bioinformatic analyses were described to ensure reproducibility of the results.

  9. Beneficial Therapeutic Effects of Sildenafil on Bone Healing in ...

    African Journals Online (AJOL)

    2018-02-23

    Feb 23, 2018 ... (SBPC) technique for detection of collagen 1 and gremlin. 1 antibodies. ..... grafting materials on early bone regeneration in osseous defects in rabbits. ... Hart K, Baur D, Hodam J, Lesoon-Wood L, Parham M, Keith. K, et al.

  10. Effects of housing systems on behavioural assessment, bone ...

    African Journals Online (AJOL)

    The birds were fed same quality and quantity of feed and water ad libitum throughout the period of the experiment which lasted for four weeks. Data were collected on behavioural observations, bone morphometry and faecal samples were analyzed to determine the helminthes egg per gram. The experiment was arranged in ...

  11. Effects of vegetation heterogeneity and surface topography on spatial scaling of net primary productivity

    Science.gov (United States)

    Chen, J. M.; Chen, X.; Ju, W.

    2013-07-01

    Due to the heterogeneous nature of the land surface, spatial scaling is an inevitable issue in the development of land models coupled with low-resolution Earth system models (ESMs) for predicting land-atmosphere interactions and carbon-climate feedbacks. In this study, a simple spatial scaling algorithm is developed to correct errors in net primary productivity (NPP) estimates made at a coarse spatial resolution based on sub-pixel information of vegetation heterogeneity and surface topography. An eco-hydrological model BEPS-TerrainLab, which considers both vegetation and topographical effects on the vertical and lateral water flows and the carbon cycle, is used to simulate NPP at 30 m and 1 km resolutions for a 5700 km2 watershed with an elevation range from 518 m to 3767 m in the Qinling Mountain, Shanxi Province, China. Assuming that the NPP simulated at 30 m resolution represents the reality and that at 1 km resolution is subject to errors due to sub-pixel heterogeneity, a spatial scaling index (SSI) is developed to correct the coarse resolution NPP values pixel by pixel. The agreement between the NPP values at these two resolutions is improved considerably from R2 = 0.782 to R2 = 0.884 after the correction. The mean bias error (MBE) in NPP modelled at the 1 km resolution is reduced from 14.8 g C m-2 yr-1 to 4.8 g C m-2 yr-1 in comparison with NPP modelled at 30 m resolution, where the mean NPP is 668 g C m-2 yr-1. The range of spatial variations of NPP at 30 m resolution is larger than that at 1 km resolution. Land cover fraction is the most important vegetation factor to be considered in NPP spatial scaling, and slope is the most important topographical factor for NPP spatial scaling especially in mountainous areas, because of its influence on the lateral water redistribution, affecting water table, soil moisture and plant growth. Other factors including leaf area index (LAI) and elevation have small and additive effects on improving the spatial scaling

  12. Effects of vegetation heterogeneity and surface topography on spatial scaling of net primary productivity

    Directory of Open Access Journals (Sweden)

    J. M. Chen

    2013-07-01

    Full Text Available Due to the heterogeneous nature of the land surface, spatial scaling is an inevitable issue in the development of land models coupled with low-resolution Earth system models (ESMs for predicting land-atmosphere interactions and carbon-climate feedbacks. In this study, a simple spatial scaling algorithm is developed to correct errors in net primary productivity (NPP estimates made at a coarse spatial resolution based on sub-pixel information of vegetation heterogeneity and surface topography. An eco-hydrological model BEPS-TerrainLab, which considers both vegetation and topographical effects on the vertical and lateral water flows and the carbon cycle, is used to simulate NPP at 30 m and 1 km resolutions for a 5700 km2 watershed with an elevation range from 518 m to 3767 m in the Qinling Mountain, Shanxi Province, China. Assuming that the NPP simulated at 30 m resolution represents the reality and that at 1 km resolution is subject to errors due to sub-pixel heterogeneity, a spatial scaling index (SSI is developed to correct the coarse resolution NPP values pixel by pixel. The agreement between the NPP values at these two resolutions is improved considerably from R2 = 0.782 to R2 = 0.884 after the correction. The mean bias error (MBE in NPP modelled at the 1 km resolution is reduced from 14.8 g C m−2 yr−1 to 4.8 g C m−2 yr−1 in comparison with NPP modelled at 30 m resolution, where the mean NPP is 668 g C m−2 yr−1. The range of spatial variations of NPP at 30 m resolution is larger than that at 1 km resolution. Land cover fraction is the most important vegetation factor to be considered in NPP spatial scaling, and slope is the most important topographical factor for NPP spatial scaling especially in mountainous areas, because of its influence on the lateral water redistribution, affecting water table, soil moisture and plant growth. Other factors including leaf area index (LAI and elevation have small and additive effects on improving

  13. Bayesian analysis of heterogeneous treatment effects for patient-centered outcomes research.

    Science.gov (United States)

    Henderson, Nicholas C; Louis, Thomas A; Wang, Chenguang; Varadhan, Ravi

    2016-01-01

    Evaluation of heterogeneity of treatment effect (HTE) is an essential aspect of personalized medicine and patient-centered outcomes research. Our goal in this article is to promote the use of Bayesian methods for subgroup analysis and to lower the barriers to their implementation by describing the ways in which the companion software beanz can facilitate these types of analyses. To advance this goal, we describe several key Bayesian models for investigating HTE and outline the ways in which they are well-suited to address many of the commonly cited challenges in the study of HTE. Topics highlighted include shrinkage estimation, model choice, sensitivity analysis, and posterior predictive checking. A case study is presented in which we demonstrate the use of the methods discussed.

  14. Effective properties of linear viscoelastic heterogeneous media: Internal variables formulation and extension to ageing behaviours

    International Nuclear Information System (INIS)

    Ricaud, J.M.; Masson, R.; Masson, R.

    2009-01-01

    The Laplace-Carson transform classically used for homogenization of linear viscoelastic heterogeneous media yields integral formulations of effective behaviours. These are far less convenient than internal variables formulations with respect to computational aspects as well as to theoretical extensions to closely related problems such as ageing viscoelasticity. Noticing that the collocation method is usually adopted to invert the Laplace-Carson transforms, we first remark that this approximation is equivalent to an internal variables formulation which is exact in some specific situations. This result is illustrated for a two-phase composite with phases obeying a compressible Maxwellian behaviour. Next, an incremental formulation allows to extend at each time step the previous general framework to ageing viscoelasticity. Finally, with the help of a creep test of a porous viscoelastic matrix reinforced with elastic inclusions, it is shown that the method yields accurate predictions (comparing to reference results provided by periodic cell finite element computations). (authors)

  15. Effect of Heterogeneous Interest Similarity on the Spread of Information in Mobile Social Networks

    Science.gov (United States)

    Zhao, Narisa; Sui, Guoqin; Yang, Fan

    2018-06-01

    Mobile social networks (MSNs) are important platforms for spreading news. The fact that individuals usually forward information aligned with their own interests inevitably changes the dynamics of information spread. Thereby, first we present a theoretical model based on the discrete Markov chain and mean field theory to evaluate the effect of interest similarity on the information spread in MSNs. Meanwhile, individuals' interests are heterogeneous and vary with time. These two features result in interest shift behavior, and both features are considered in our model. A leveraging simulation demonstrates the accuracy of our model. Moreover, the basic reproduction number R0 is determined. Further extensive numerical analyses based on the model indicate that interest similarity has a critical impact on information spread at the early spreading stage. Specifically, the information always spreads more quickly and widely if the interest similarity between an individual and the information is higher. Finally, five actual data sets from Sina Weibo illustrate the validity of the model.

  16. Effects of heterogeneity on recrystallization kinetics of nanocrystalline copper prepared by dynamic plastic deformation

    DEFF Research Database (Denmark)

    Lin, Fengxiang; Zhang, Yubin; Tao, Nairong

    2014-01-01

    to develop a heterogeneous structure, consisting of regions with different textures and microstructures. This heterogeneity within the deformed structure leads to the formation of severely clustered grains in partially recrystallized samples. The recrystallization kinetic curve shows an Avrami exponent less...... recrystallization kinetics. The hardness of the two samples was measured, and the mechanical properties before and after partial recrystallization of both samples are discussed based on the presence of structural heterogeneities on the macroscopic and the microscopic scale....

  17. Fixed and mobile-bearing total ankle prostheses: Effect on tibial bone strain.

    Science.gov (United States)

    Terrier, Alexandre; Fernandes, Caroline Sieger; Guillemin, Maïka; Crevoisier, Xavier

    2017-10-01

    Total ankle replacement is associated to a high revision rate. To improve implant survival, the potential advantage of prostheses with fixed bearing compared to mobile bearing is unclear. The objective of this study was to test the hypothesis that fixed and mobile bearing prostheses are associated with different biomechanical quantities typically associated to implant failure. With a validated finite element model, we compared three cases: a prosthesis with a fixed bearing, a prosthesis with a mobile bearing in a centered position, and a prosthesis with mobile bearing in an eccentric position. Both prostheses were obtained from the same manufacturer. They were tested on seven tibias with maximum axial compression force during walking. We tested the hypothesis that there was a difference of bone strain, bone-implant interfacial stress, and bone support between the three cases. We also evaluated, for the three cases, the correlations between bone support, bone strain and bone-implant interfacial stress. There were no statistically significant differences between the three cases. Overall, bone support was mainly trabecular, and less effective in the posterior side. Bone strain and bone-implant interfacial stress were strongly correlated to bone support. Even if slight differences are observed between fixed and mobile bearing, it is not enough to put forward the superiority of one of these implants regarding their reaction to axial compression. When associated to the published clinical results, our study provides no argument to warn surgeons against the use of two-components fixed bearing implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Heterogeneous effects of health insurance on out-of-pocket expenditure on medicines in Mexico.

    Science.gov (United States)

    Wirtz, Veronika J; Santa-Ana-Tellez, Yared; Servan-Mori, Edson; Avila-Burgos, Leticia

    2012-01-01

    Given the importance of health insurance for financing medicines and recent policy changes designed to reduce health-related out-of-pocket expenditure (OOPE) in Mexico, our study examined and analyzed the effect of health insurance on the probability and amount of OOPE for medicines and the proportion spent from household available expenditure (AE) funds. We conducted a cross-sectional analysis by using the Mexican National Household Survey of Income and Expenditures for 2008. Households were grouped according to household medical insurance type (Social Security, Seguro Popular, mixed, or no affiliation). OOPE for medicines and health costs, and the probability of occurrence, were estimated with linear regression models; subsequently, the proportion of health expenditures from AE was calculated. The Heckman selection procedure was used to correct for self-selection of health expenditure; a propensity score matching procedure and an alternative procedure using instrumental variables were used to correct for heterogeneity between households with and without Seguro Popular. OOPE in medicines account for 66% of the total health expenditures and 5% of the AE. Households with health insurance had a lower probability of OOPE for medicines than their comparison groups. There was heterogeneity in the health insurance effect on the proportion of OOPE for medicines out of the AE, with a reduction of 1.7% for households with Social Security, 1.4% for mixed affiliation, but no difference between Seguro Popular and matched households without insurance. Medicines were the most prevalent component of health expenditures in Mexico. We recommend improving access to health services and strengthening access to medicines to reduce high OOPE. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  19. Effect of microstructure on micromechanical performance of dry cortical bone tissues

    International Nuclear Information System (INIS)

    Yin Ling; Venkatesan, Sudharshan; Kalyanasundaram, Shankar; Qin Qinghua

    2009-01-01

    The mechanical properties of bone depend on composition and structure. Previous studies have focused on macroscopic fracture behavior of bone. In the present study, we performed microindentation studies to understand the deformation properties and microcrack-microstructure interactions of dry cortical bone. Dry cortical bone tissues from lamb femurs were tested using Vickers indentation with loads of 0.245-9.8 N. We examined the effect of bone microstructure on deformation and crack propagation using scanning electron microscopy (SEM). The results showed the significant effect of cortical bone microstructure on indentation deformation and microcrack propagation. The indentation deformation of the dry cortical bone was basically plastic at any applied load with a pronounced viscoelastic recovery, in particular at lower loads. More microcracks up to a length of approximately 20 μm occurred when the applied load was increased. At loads of 4.9 N and higher, most microcracks were found to develop from the boundaries of haversian canals, osteocyte lacunae and canaliculi. Some microcracks propagated from the parallel direction of the longitudinal interstitial lamellae. At loads 0.45 N and lower, no visible microcracks were observed.

  20. Male Hypogonadism and Osteoporosis: The Effects, Clinical Consequences, and Treatment of Testosterone Deficiency in Bone Health

    Science.gov (United States)

    Houdek, Devon

    2017-01-01

    It is well recognized that bone loss accelerates in hypogonadal states, with female menopause being the classic example of sex hormones affecting the regulation of bone metabolism. Underrepresented is our knowledge of the clinical and metabolic consequences of overt male hypogonadism, as well as the more subtle age-related decline in testosterone on bone quality. While menopause and estrogen deficiency are well-known risk factors for osteoporosis in women, the effects of age-related testosterone decline in men on bone health are less well known. Much of our knowledge comes from observational studies and retrospective analysis on small groups of men with variable causes of primary or secondary hypogonadism and mild to overt testosterone deficiencies. This review aims to present the current knowledge of the consequences of adult male hypogonadism on bone metabolism. The direct and indirect effects of testosterone on bone cells will be explored as well as the important differences in male osteoporosis and assessment as compared to that in females. The clinical consequence of both primary and secondary hypogonadism, as well as testosterone decline in older males, on bone density and fracture risk in men will be summarized. Finally, the therapeutic options and their efficacy in male osteoporosis and hypogonadism will be discussed. PMID:28408926

  1. Male Hypogonadism and Osteoporosis: The Effects, Clinical Consequences, and Treatment of Testosterone Deficiency in Bone Health

    Directory of Open Access Journals (Sweden)

    Gary Golds

    2017-01-01

    Full Text Available It is well recognized that bone loss accelerates in hypogonadal states, with female menopause being the classic example of sex hormones affecting the regulation of bone metabolism. Underrepresented is our knowledge of the clinical and metabolic consequences of overt male hypogonadism, as well as the more subtle age-related decline in testosterone on bone quality. While menopause and estrogen deficiency are well-known risk factors for osteoporosis in women, the effects of age-related testosterone decline in men on bone health are less well known. Much of our knowledge comes from observational studies and retrospective analysis on small groups of men with variable causes of primary or secondary hypogonadism and mild to overt testosterone deficiencies. This review aims to present the current knowledge of the consequences of adult male hypogonadism on bone metabolism. The direct and indirect effects of testosterone on bone cells will be explored as well as the important differences in male osteoporosis and assessment as compared to that in females. The clinical consequence of both primary and secondary hypogonadism, as well as testosterone decline in older males, on bone density and fracture risk in men will be summarized. Finally, the therapeutic options and their efficacy in male osteoporosis and hypogonadism will be discussed.

  2. Effects of Resveratrol Supplementation on Bone Growth in Young Rats and Microarchitecture and Remodeling in Ageing Rats

    Directory of Open Access Journals (Sweden)

    Alice M. C. Lee

    2014-12-01

    Full Text Available Osteoporosis is a highly prevalent skeletal disorder in the elderly that causes serious bone fractures. Peak bone mass achieved at adolescence has been shown to predict bone mass and osteoporosis related risk fracture later in life. Resveratrol, a natural polyphenol compound, may have the potential to promote bone formation and reduce bone resorption. However, it is unclear whether it can aid bone growth and bone mass accumulation during rapid growth and modulate bone metabolism during ageing. Using rat models, the current study investigated the potential effects of resveratrol supplementation during the rapid postnatal growth period and in late adulthood (early ageing on bone microarchitecture and metabolism. In the growth trial, 4-week-old male hooded Wistar rats on a normal chow diet were given resveratrol (2.5 mg/kg/day or vehicle control for 5 weeks. In the ageing trial, 6-month-old male hooded Wistar rats were treated with resveratrol (20 mg/kg/day or vehicle for 3 months. Treatment effects in the tibia were examined by μ-computer tomography (μ-CT analysis, bone histomorphometric measurements and reverse transcription-polymerase chain reaction (RT-PCR gene expression analysis. Resveratrol treatment did not affect trabecular bone volume and bone remodeling indices in the youth animal model. Resveratrol supplementation in the early ageing rats tended to decrease trabecular bone volume, Sirt1 gene expression and increased expression of adipogenesis-related genes in bone, all of which were statistically insignificant. However, it decreased osteocalcin expression (p = 0.03. Furthermore, serum levels of bone resorption marker C-terminal telopeptides type I collagen (CTX-1 were significantly elevated in the resveratrol supplementation group (p = 0.02 with no changes observed in serum levels of bone formation marker alkaline phosphatase (ALP. These results in rat models suggest that resveratrol supplementation does not significantly affect bone

  3. Insulin-like growth factor I has independent effects on bone matrix formation and cell replication

    International Nuclear Information System (INIS)

    Hock, J.M.; Centrella, M.; Canalis, E.

    1988-01-01

    The effects of insulin-like growth factor-I (IGF-I) and insulin on bone matrix synthesis and bone cell replication were studied in cultured 21-day-old fetal rat calvariae. Histomorphometry techniques were developed to measure the incorporation of [2,3- 3 H]proline and [methyl- 3 H]thymidine into bone matrix and bone cell nuclei, respectively, using autoradiographs of sagittal sections of calvariae cultured with IGF-I, insulin, or vehicle for up to 96 h. To confirm an effect on bone formation, IGF-I was also studied for its effects on [ 3 H]proline incorporation into collagenase-digestible protein (CDP) and noncollagen protein and on [ 3 H]thymidine incorporation into acid-precipitable material (DNA). IGF-I at 10(-9)-10(-7) M significantly increased the rate of bone matrix apposition and CDP after 24 h by 45-50% and increased cell labeling by 8-fold in the osteoprogenitor cell zone, by 4-fold in the osteoblast cell zone, and by 2-fold in the periosteal fibroblast zone. Insulin at 10(-9)-10(-6) M also increased matrix apposition rate and CDP by 40-50%, but increased cell labeling by 2-fold only at a concentration of 10(-7) M or higher and then only in the osteoprogenitor cell zone. When hydroxyurea was added to IGF-I-treated bones, the effects of IGF-I on DNA synthesis were abolished, but the increase in bone matrix apposition induced by IGF-I was only partly diminished. In conclusion, IGF-I stimulates matrix synthesis in calvariae, an effect that is partly, although not completely, dependent on its stimulatory effect on DNA synthesis

  4. Patterns and effects of GC3 heterogeneity and parsimony informative sites on the phylogenetic tree of genes.

    Science.gov (United States)

    Ma, Shuai; Wu, Qi; Hu, Yibo; Wei, Fuwen

    2018-05-20

    The explosive growth in genomic data has provided novel insights into the conflicting signals hidden in phylogenetic trees. Although some studies have explored the effects of the GC content and parsimony informative sites (PIS) on the phylogenetic tree, the effect of the heterogeneity of the GC content at the first/second/third codon position on parsimony informative sites (GC1/2/3 PIS ) among different species and the effect of PIS on phylogenetic tree construction remain largely unexplored. Here, we used two different mammal genomic datasets to explore the patterns of GC1/2/3 PIS heterogeneity and the effect of PIS on the phylogenetic tree of genes: (i) all GC1/2/3 PIS have obvious heterogeneity between different mammals, and the levels of heterogeneity are GC3 PIS  > GC2 PIS  > GC1 PIS ; (ii) the number of PIS is positively correlated with the metrics of "good" gene tree topologies, and excluding the third codon position (C3) decreases the quality of gene trees by removing too many PIS. These results provide novel insights into the heterogeneity pattern of GC1/2/3 PIS in mammals and the relationship between GC3/PIS and gene trees. Additionally, it is necessary to carefully consider whether to exclude C3 to improve the quality of gene trees, especially in the super-tree method. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Low effect of young afforestations on bird communities inhabiting heterogeneous Mediterranean cropland

    Directory of Open Access Journals (Sweden)

    Juan S. Sánchez-Oliver

    2015-12-01

    Full Text Available Afforestation programs such as the one promoted by the EU Common Agricultural Policy have spread tree plantations on former cropland. These afforestations attract generalist forest and ubiquitous species but may cause severe damage to open habitat species, especially birds of high conservation value. We investigated the effects of young (<20 yr tree plantations dominated by pine P. halepensis on bird communities inhabiting the adjacent open farmland habitat in central Spain. We hypothesize that pine plantations located at shorter distances from open fields and with larger surface would affect species richness and conservation value of bird communities. Regression models controlling for the influence of land use types around plantations revealed positive effects of higher distance to pine plantation edge on community species richness in winter, and negative effects on an index of conservation concern (SPEC during the breeding season. However, plantation area did not have any effect on species richness or community conservation value. Our results indicate that the effects of pine afforestation on bird communities inhabiting Mediterranean cropland are diluted by heterogeneous agricultural landscapes.

  6. Revisiting Rebound Effects from Material Resource Use. Indications for Germany Considering Social Heterogeneity

    Directory of Open Access Journals (Sweden)

    Johannes Buhl

    2014-02-01

    Full Text Available In contrast to the original investigation by William Stanley Jevons, compensations of energy savings due to improved energy efficiency are mostly analyzed by providing energy consumption or greenhouse gas emissions. In support of a sustainable resource management, this paper analyzes so-called rebound effects based on resource use. Material flows and associated expenditures by households allow for calculating resource intensities and marginal propensities to consume. Marginal propensities to consume are estimated from data of the German Socio-Economic Panel (SOEP in order to account for indirect rebound effects for food, housing and mobility. Resource intensities are estimated in terms of total material requirements per household final consumption expenditures along the Classification of Individual Consumption according to Purpose (COICOP. Eventually, rebound effects are indicated on the basis of published saving scenarios in resource and energy demand for Germany. In sum, compensations due to rebound effects are lowest for food while the highest compensations are induced for mobility. This is foremost the result of a relatively high resource intensity of food and a relatively low resource intensity in mobility. Findings are provided by giving various propensity scenarios in order to cope with income differences in Germany. The author concludes that policies on resource conservation need to reconsider rebound effects under the aspect of social heterogeneity.

  7. Effect of protein malnutrition on the metabolism of bone collagen in albino rats

    Energy Technology Data Exchange (ETDEWEB)

    Rao, J S; Rao, V H [Central Leather Research Inst., Madras (India)

    1981-01-01

    The effect of protein malnutrition on the metabolism of collagen in bone was studied in young female albino rats after a single injection of /sup 3/H-proline. Both specific and total radioactivities of hydroxyproline in the total collagen of the bone were found to decrease in the protein-deficient animals, indicating decreased rate of collagen synthesis. In the urine the amount of hydroxyproline excreted and total radioactivity of /sup 3/H-hydroxyproline were greatly decreased. The results of the present investigation therefore clearly indicate decreased synthesis and catabolism of collagen in bones of protein deficient animals compared to controls.

  8. Effect of Different Loading Conditions on the Nucleation and Development of Shear Zones Around Material Heterogeneities

    Science.gov (United States)

    Rybacki, E.; Nardini, L.; Morales, L. F.; Dresen, G.

    2017-12-01

    Rock deformation at depths in the Earth's crust is often localized in high temperature shear zones, which occur in the field at different scales and in a variety of lithologies. The presence of material heterogeneities has long been recognized to be an important cause for shear zones evolution, but the mechanisms controlling initiation and development of localization are not fully understood, and the question of which loading conditions (constant stress or constant deformation rate) are most favourable is still open. To better understand the effect of boundary conditions on shear zone nucleation around heterogeneities, we performed a series of torsion experiments under constant twist rate (CTR) and constant torque (CT) conditions in a Paterson-type deformation apparatus. The sample assemblage consisted of copper-jacketed Carrara marble hollow cylinders with one weak inclusion of Solnhofen limestone. The CTR experiments were performed at maximum bulk strain rates of 1.8-1.9*10-4 s-1, yielding shear stresses of 19-20 MPa. CT tests were conducted at shear stresses between 18.4 and 19.8 MPa resulting in shear strain rates of 1-2*10-4 s-1. All experiments were run at 900 °C temperature and 400 MPa confining pressure. Maximum bulk shear strains (γ) were ca. 0.3 and 1. Strain localized within the host marble in front of the inclusion in an area termed process zone. Here grain size reduction is intense and local shear strain (estimated from markers on the jackets) is up to 8 times higher than the applied bulk strain, rapidly dropping to 2 times higher at larger distance from the inclusion. The evolution of key microstructural parameters such as average grain size and average grain orientation spread (GOS, a measure of lattice distortion) within the process zone, determined by electron backscatter diffraction analysis, differs significantly as a function of loading conditions. Both parameters indicate that, independent of bulk strain and distance from the inclusion, the

  9. Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice

    Science.gov (United States)

    Yu, Kanglun; Doherty, Alison H.; Genik, Paula C.; Gookin, Sara E.; Roteliuk, Danielle M.; Wojda, Samantha J.; Jiang, Zhi-Sheng; McGee-Lawrence, Meghan E.; Weil, Michael M.; Donahue, Seth W.

    2017-11-01

    During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation.

  10. The Preventive Effect of Calcium Supplementation on Weak Bones Caused by the Interaction of Exercise and Food Restriction in Young Female Rats During the Period from Acquiring Bone Mass to Maintaining Bone Mass.

    Science.gov (United States)

    Aikawa, Yuki; Agata, Umon; Kakutani, Yuya; Kato, Shoyo; Noma, Yuichi; Hattori, Satoshi; Ogata, Hitomi; Ezawa, Ikuko; Omi, Naomi

    2016-01-01

    Increasing calcium (Ca) intake is important for female athletes with a risk of weak bone caused by inadequate food intake. The aim of the present study was to examine the preventive effect of Ca supplementation on low bone strength in young female athletes with inadequate food intake, using the rats as an experimental model. Seven-week-old female Sprague-Dawley rats were divided into four groups: the sedentary and ad libitum feeding group (SED), voluntary running exercise and ad libitum feeding group (EX), voluntary running exercise and 30% food restriction group (EX-FR), and a voluntary running exercise, 30% food-restricted and high-Ca diet group (EX-FR+Ca). To Ca supplementation, we used 1.2% Ca diet as "high-Ca diet" that contains two-fold Ca of normal Ca diet. The experiment lasted for 12 weeks. As a result, the energy availability, internal organ weight, bone strength, bone mineral density, and Ca absorption in the EX-FR group were significantly lower than those in the EX group. The bone strength and Ca absorption in the EX-FR+Ca group were significantly higher than those in the EX-FR group. However, the bone strength in the EX-FR+Ca group did not reach that in the EX group. These results suggested that Ca supplementation had a positive effect on bone strength, but the effect was not sufficient to prevent lower bone strength caused by food restriction in young female athletes.

  11. Analytic Investigation Into Effect of Population Heterogeneity on Parameter Ratio Estimates

    International Nuclear Information System (INIS)

    Schinkel, Colleen; Carlone, Marco; Warkentin, Brad; Fallone, B. Gino

    2007-01-01

    Purpose: A homogeneous tumor control probability (TCP) model has previously been used to estimate the α/β ratio for prostate cancer from clinical dose-response data. For the ratio to be meaningful, it must be assumed that parameter ratios are not sensitive to the type of tumor control model used. We investigated the validity of this assumption by deriving analytic relationships between the α/β estimates from a homogeneous TCP model, ignoring interpatient heterogeneity, and those of the corresponding heterogeneous (population-averaged) model that incorporated heterogeneity. Methods and Materials: The homogeneous and heterogeneous TCP models can both be written in terms of the geometric parameters D 50 and γ 50 . We show that the functional forms of these models are similar. This similarity was used to develop an expression relating the homogeneous and heterogeneous estimates for the α/β ratio. The expression was verified numerically by generating pseudo-data from a TCP curve with known parameters and then using the homogeneous and heterogeneous TCP models to estimate the α/β ratio for the pseudo-data. Results: When the dominant form of interpatient heterogeneity is that of radiosensitivity, the homogeneous and heterogeneous α/β estimates differ. This indicates that the presence of this heterogeneity affects the value of the α/β ratio derived from analysis of TCP curves. Conclusions: The α/β ratio estimated from clinical dose-response data is model dependent-a heterogeneous TCP model that accounts for heterogeneity in radiosensitivity will produce a greater α/β estimate than that resulting from a homogeneous TCP model

  12. The effect of bisphosphonates on bone mineral density in patients with ankylosing spondylitis in daily clinical practice

    NARCIS (Netherlands)

    Arends, S.; Veneberg, J.G.; Wink, F.R.; Bos, R.; Brouwer, E.; Van Der Veer, E.; Bootsma, H.; Van Roon, E.N.; Maas, F.; Spoorenberg, A.

    2016-01-01

    Background: Ankylosing spondylitis (AS) is not only characterized by excessive bone formation, but also by excessive bone loss which may lead to low bone mineral density (BMD). So far, little is known about the effect of treatment with bisphosphonates on BMD in patients with AS. Objectives: To

  13. Effect of low-dose prednisone (with calcium and calcitriol supplementation) on calcium and bone metabolism in healthy volunteers

    NARCIS (Netherlands)

    Lems, W. F.; van Veen, G. J.; Gerrits, M. I.; Jacobs, J. W.; Houben, H. H.; van Rijn, H. J.; Bijlsma, J. W.

    1998-01-01

    The administration of moderate to high doses of corticosteroids is associated with bone loss. This probably results from the uncoupling of bone formation (decreased) and bone resorption (unchanged or increased). We examined the effect of low-dose (10 mg/day) prednisone (LDP) and the possible

  14. Effects of lead shot ingestion on bone mineralization in a population of red-legged partridge (Alectoris rufa)

    International Nuclear Information System (INIS)

    Álvarez-Lloret, Pedro; Rodríguez-Navarro, Alejandro B.; Romanek, Christopher S.; Ferrandis, Pablo; Martínez-Haro, Mónica; Mateo, Rafael

    2014-01-01

    The effect of lead (Pb) toxicity on bone mineralization was investigated in a wild population of red-legged partridge (Alectoris rufa) inhabiting a farmland area contaminated with Pb-shot from recreational hunting activities in Albacete, a southeastern province of Spain. Femora from 40 specimens of red-legged partridge were analyzed for Pb by graphite furnace atomic absorption spectroscopy (GF-AAS), and for bone composition by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The FTIR and DRX data of bone were analyzed in detail to determine possible alterations in bone mineral chemistry and crystallinity due to Pb toxicity. Results showed a marked decrease in the degree of mineralization as Pb concentrations in bone tissue increased while XRD analyses showed that the crystallinity of apatite crystals increased with the Pb load in bone. These load-dependent effects are indicative that Pb contamination altered bone remodeling by reducing new bone mineral formation and demonstrate that bone quality is a sensitive indicator of adverse effects on wild bird populations exposed to Pb pollution. - Highlights: •The effect of Pb toxicity on bone mineralization was investigated in partridges. •Lead exposure decreased bone mineralization degree. •Demonstrated usefulness of FTIR and DRX to evaluate alterations in bone chemistry and crystallinity by Pb exposure

  15. Effects of lead shot ingestion on bone mineralization in a population of red-legged partridge (Alectoris rufa)

    Energy Technology Data Exchange (ETDEWEB)

    Álvarez-Lloret, Pedro, E-mail: pedroalvarez@geol.uniovi.es [Department of Mineralogy and Petrology, University of Granada, Avd. Fuentenueva s/n, 18002 Granada (Spain); Departament of Geology, University of Oviedo, C/Jesús Arias de Velasco, s/n, 33005 Oviedo (Spain); Rodríguez-Navarro, Alejandro B. [Department of Mineralogy and Petrology, University of Granada, Avd. Fuentenueva s/n, 18002 Granada (Spain); Romanek, Christopher S. [Department of Earth and Environmental Sciences, University of Kentucky, Lexington, KY (United States); Ferrandis, Pablo [Department of Plant Production and Agricultural Technology, E.T.S. Ingenieros Agrónomos, University of Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete (Spain); Martínez-Haro, Mónica [Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC, UCLM, JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain); IMAR-Instituto do Mar, Department of Life Sciences, University of Coimbra, 3004-517 Coimbra (Portugal); Mateo, Rafael [Instituto de Investigación en Recursos Cinegéticos, IREC (CSIC, UCLM, JCCM), Ronda de Toledo s/n, 13005 Ciudad Real (Spain)

    2014-01-01

    The effect of lead (Pb) toxicity on bone mineralization was investigated in a wild population of red-legged partridge (Alectoris rufa) inhabiting a farmland area contaminated with Pb-shot from recreational hunting activities in Albacete, a southeastern province of Spain. Femora from 40 specimens of red-legged partridge were analyzed for Pb by graphite furnace atomic absorption spectroscopy (GF-AAS), and for bone composition by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The FTIR and DRX data of bone were analyzed in detail to determine possible alterations in bone mineral chemistry and crystallinity due to Pb toxicity. Results showed a marked decrease in the degree of mineralization as Pb concentrations in bone tissue increased while XRD analyses showed that the crystallinity of apatite crystals increased with the Pb load in bone. These load-dependent effects are indicative that Pb contamination altered bone remodeling by reducing new bone mineral formation and demonstrate that bone quality is a sensitive indicator of adverse effects on wild bird populations exposed to Pb pollution. - Highlights: •The effect of Pb toxicity on bone mineralization was investigated in partridges. •Lead exposure decreased bone mineralization degree. •Demonstrated usefulness of FTIR and DRX to evaluate alterations in bone chemistry and crystallinity by Pb exposure.

  16. [Effects of the combined calcitonin and sodium etidronate therapy in Paget's disease of bone].

    Science.gov (United States)

    Nuti, R; Turchetti, V; Righi, G; Vattimo, A

    1982-03-03

    The therapy of Paget's bone disease is essentially based on the use of calcitonin and diphosphonates: both drugs, if used in large doses for long periods, have shown themselves able to provoke particular side-effects. It was, therefore, decided to study the therapeutic efficacy of combined low-dosage treatment using synthetic salmon calcitonin and sodium-etidronate on a group of patients with Paget's osteodystrophy. A clear evident diminution in plasma alkaline phosphatase, hydroxyprolinuria and whole body retention (WBR) of MDP-Tc99m was observed, demonstrating a reduction of metabolic turnover in the bone. No changes in the bone mass (BMC), evaluated by bone mineral detector, were observed at the end of treatment. With this treatment the plateau effect was shown to be appreciably less than normally occurs when either calcitonin or sodium etidronate are used alone.

  17. Effects of total flavonoids from Drynariae Rhizoma prevent bone loss in vivo and in vitro

    Directory of Open Access Journals (Sweden)

    Shuang-hong Song

    2016-12-01

    Full Text Available Estrogen deficiency is one of the major causes of osteoporosis in postmenopausal women. Drynariae Rhizoma is a widely used traditional Chinese medicine for the treatment of bone diseases. In this study, we investigated the therapeutic effects of the total Drynariae Rhizoma flavonoids (DRTF on estrogen deficiency-induced bone loss using an ovariectomized rat model and osteoblast-like MC3T3-E1 cells. Our results indicated that DRTF produced osteo-protective effects on the ovariectomized rats in terms of bone loss reduction, including decreased levels of bone turnover markers, enhanced biomechanical femur strength and trabecular bone microarchitecture deterioration prevention. In vitro experiments revealed that the actions of DRTF on regulating osteoblastic activities were mediated by the estrogen receptor (ER dependent pathway. Our data also demonstrated that DRTF inhibited osteoclastogenesis via up-regulating osteoprotegrin (OPG, as well as down-regulating receptor activator of NF–κB ligand (RANKL expression. In conclusion, this study indicated that DRTF treatment effectively suppressed bone mass loss in an ovariectomized rat model, and in vitro evidence suggested that the effects were exerted through actions on both osteoblasts and osteoclasts. Keywords: Osteoporosis, Osteoblast, Osteoclast, Ovariectomy, Drynariae Rhizoma

  18. Additive Genetic Effects on Circulating Periostin Contribute to the Heritability of Bone Microstructure.

    Science.gov (United States)

    Bonnet, N; Biver, E; Durosier, C; Chevalley, T; Rizzoli, R; Ferrari, S

    2015-07-01

    Genetic factors account for 60-80% of the areal bone mineral density (aBMD) variance, whereas the heritability of bone microstructure is not clearly established. aBMD and microstructure are under the control of osteocytes, which regulate bone formation through the expression of molecules such as sclerostin (SOST) and periostin (POSTN). We hypothesized that additive genetic effects contribute to serum levels of SOST and POSTN and thereby to the individual variance of bone microstructure. In a retrospective analysis of 432 subjects from the Geneva Retiree Cohort age 64.9 ± 1.4 years and 96 of their offspring age 37.9 ± 5.7 years, we measured serum SOST (sSOST) and serum POSTN (sPOSTN), distal radius and tibia microstructure, hip and lumbar spine aBMD, and bone turnover markers, Heritability (h(2), %) was calculated as twice the slope of the regression (β) between parents and offspring. cPOSTN levels were significantly higher in men than women and in offspring than parents. h(2) values for bone microstructural traits ranged from 22-64% depending on the envelope (trabecular [Tb] or cortical [Ct]) and skeletal site (radius or tibia), whereas h(2) for sPOSTN and sSOST was 50% and 40%, respectively. sPOSTN was positively associated with Tb bone volume on total volume and Ct thickness, and negatively with Ct porosity. The associations for Ct parameters remain significant after adjustment for propetide of type-I procollagen, cross-linked telopeptide of type I collagen, femoral neck aBMD, sex or age. After adjustment of bone traits for sPOSTN, h(2) values decreased for several Tb and Ct bone parameters, but not for aBMD. In contrast, adjusting for sSOST did not alter h(2) values for bone traits. Additive genetic effects account for a substantial proportion of the individual variance of bone microstructure, sPOSTN, and sSOST. sPOSTN is largely inherited as a sex-related trait and carries an important contribution to the heritability of bone microstructure, indicating that

  19. Effect of heterogeneity on enhanced reductive dechlorination: Analysis of remediation efficiency and groundwater acidification

    Science.gov (United States)

    Brovelli, A.; Lacroix, E.; Robinson, C. E.; Gerhard, J.; Holliger, C.; Barry, D. A.

    2011-12-01

    Enhanced reductive dehalogenation is an attractive in situ treatment technology for chlorinated contaminants. The process includes two acid-forming microbial reactions: fermentation of an organic substrate resulting in short-chain fatty acids, and dehalogenation resulting in hydrochloric acid. The accumulation of acids and the resulting drop of groundwater pH are controlled by the mass and distribution of chlorinated solvents in the source zone, type of electron donor, alternative terminal electron acceptors available and presence of soil mineral phases able to buffer the pH (such as carbonates). Groundwater acidification may reduce or halt microbial activity, and thus dehalogenation, significantly increasing the time and costs required to remediate the aquifer. In previous work a detailed geochemical and groundwater flow simulator able to model the fermentation-dechlorination reactions and associated pH change was developed. The model accounts for the main processes influencing microbial activity and groundwater pH, including the groundwater composition, the electron donor used and soil mineral phase interactions. In this study, the model was applied to investigate how spatial variability occurring at the field scale affects dechlorination rates, groundwater pH and ultimately the remediation efficiency. Numerical simulations were conducted to examine the influence of heterogeneous hydraulic conductivity on the distribution of the injected, fermentable substrate and on the accumulation/dilution of the acidic products of reductive dehalogenation. The influence of the geometry of the DNAPL source zone was studied, as well as the spatial distribution of soil minerals. The results of this study showed that the heterogeneous distribution of the soil properties have a potentially large effect on the remediation efficiency. For examples, zones of high hydraulic conductivity can prevent the accumulation of acids and alleviate the problem of groundwater acidification. The

  20. Serological markers suggest heterogeneity of effectiveness of malaria control interventions on Bioko Island, equatorial Guinea.

    Directory of Open Access Journals (Sweden)

    Jackie Cook

    Full Text Available In order to control and eliminate malaria, areas of on-going transmission need to be identified and targeted for malaria control interventions. Immediately following intense interventions, malaria transmission can become more heterogeneous if interventions are more successful in some areas than others. Bioko Island, Equatorial Guinea, has been subject to comprehensive malaria control interventions since 2004. This has resulted in substantial reductions in the parasite burden, although this drop has not been uniform across the island.In 2008, filter paper blood samples were collected from 7387 people in a cross-sectional study incorporating 18 sentinel sites across Bioko, Equatorial Guinea. Antibodies were measured to P. falciparum Apical Membrane Antigen-1 (AMA-1 by Enzyme Linked Immunosorbent Assay (ELISA. Age-specific seropositivity rates were used to estimate seroconversion rates (SCR. Analysis indicated there had been at least a 60% decline in SCR in four out of five regions on the island. Changes in SCR showed a high degree of congruence with changes in parasite rate (PR and with regional reductions in all cause child mortality. The mean age adjusted concentration of anti-AMA-1 antibodies was mapped to identify areas where individual antibody responses were higher than expected. This approach confirmed the North West of the island as a major focus of continuing infection and an area where control interventions need to be concentrated or re-evaluated.Both SCR and PR revealed heterogeneity in malaria transmission and demonstrated the variable effectiveness of malaria control measures. This work confirms the utility of serological analysis as an adjunct measure for monitoring transmission. Age-specific seroprevalence based evidence of changes in transmission over time will be of particular value when no baseline data are available. Importantly, SCR data provide additional evidence to link malaria control activities to contemporaneous

  1. The effects of oestrogens on linear bone growth

    DEFF Research Database (Denmark)

    Juul, A

    2001-01-01

    Regulation of linear bone growth in children and adolescents comprises a complex interaction of hormones and growth factors. Growth hormone (GH) is considered to be the key hormone regulator of linear growth in childhood. The pubertal increase in growth velocity associated with GH has traditionally...... been attributed to testicular androgen secretion in boys, and to oestrogens or adrenal androgen secretion in girls. Research data indicating that oestrogen may be the principal hormone stimulating the pubertal growth spurt in boys as well as girls is reviewed. Such an action is mediated by oestrogen...... female growth spurt despite lack of androgen action. Oestrogens may also influence linear bone growth indirectly via modulation of the GH-insulin-like growth factor-I (IGF-I) axis. Thus, ER blockade diminishes endogenous GH secretion, androgen receptor (AR) blockade increases GH secretion in peripubertal...

  2. Effects of bone substitute architecture and surface properties on cell response, angiogenesis, and structure of new bone

    NARCIS (Netherlands)

    Bobbert, F.S.L.; Zadpoor, A.A.

    2017-01-01

    The success of bone substitutes used to repair bone defects such as critical sized defects depends on the architecture of the porous biomaterial. The architectural parameters and surface properties affect cell seeding efficiency, cell response, angiogenesis, and eventually bone formation. The

  3. Effect of salidroside on radiation-induced bone marrow adipogenesis

    International Nuclear Information System (INIS)

    Zhu Jincan; Chen Xiaoyu; Liu Chengcheng; Zhu Aizhen; Liu Shantao; Liu Gexiu

    2014-01-01

    Objective: To investigate the potential and underlying molecular mechanism of salidroside in ameliorating radiation-induced bone marrow adipogenesis and stimulating hematopoiesis. Methods: The female BALB/c mice aged 6-7 weeks were randomly divided into normal control group, radiation group and salidroside group. The radiation group and salidroside group were irradiated with 6.0 Gy of "6"0Co γ-rays. The salidroside group was intraperitoneally injected with 30 mg·kg"-"1·d"-"1 salidroside at 12 h and then every day until 8th d after radiation. The normal control group and radiation group were treated with equal volume of saline as control of salidroside. At 14 d after radiation, the mice weight, peripheral blood count, femur bone marrow histology, and the proportion of adipocyte area were measured, and the expressions of PPAR-γ and FABP4 were detected by q-PCR. Results: After irradiation, the numbers of white blood cells, hemoglobin and platelet in peripheral blood were reduced obviously, and the percentage of adipocyte area was increased significantly. Compared with mice in the radiation group, salidroside inhibited adipogenesis and reduced the proportion of adipocyte area (t = 13.31, P < 0.05) by reducing the expressions of PPAR-γ and FABP4 (t = 8.64, 13.19, P < 0.05). The number of white blood cells was partly recovered at 7 d after irradiation (t = 5.80, P < 0.05). Both white blood cells and hemoglobinin in peripheral blood of the salidroside group were higher than those in the radiation group at 14 d after irradiation. Conclusions: Salidroside could inhibit radiation-induced bone marrow adipogenesis and regulate bone marrow microenvironment, thereby promotes hematopoietic recovery in mice after radiation injury. (authors)

  4. Effects of radiation therapy on growing long bones

    International Nuclear Information System (INIS)

    De Smet, A.A.; Kuhns, L.R.; Fayos, J.V.; Holt, J.F.

    1976-01-01

    Characteristic radiographic changes were seen in six of 14 children who received radiation therapy to the epiphyseal plate of a long bone. These changes, which include metaphyseal sclerosis, metaphyseal fraying, and epiphyseal plate widening, resemble rickets. In three patients, these changes were followed by development of a broad metaphyseal band of increased density. The absence of metaphyseal changes may indicate sterilization of cartilage cells and may be predictive of significant limb shortening

  5. Effects of Active Mastication on Chronic Stress-Induced Bone Loss in Mice.

    Science.gov (United States)

    Azuma, Kagaku; Furuzawa, Manabu; Fujiwara, Shu; Yamada, Kumiko; Kubo, Kin-ya

    2015-01-01

    Chronic psychologic stress increases corticosterone levels, which decreases bone density. Active mastication or chewing attenuates stress-induced increases in corticosterone. We evaluated whether active mastication attenuates chronic stress-induced bone loss in mice. Male C57BL/6 (B6) mice were randomly divided into control, stress, and stress/chewing groups. Stress was induced by placing mice in a ventilated restraint tube (60 min, 2x/day, 4 weeks). The stress/chewing group was given a wooden stick to chew during the experimental period. Quantitative micro-computed tomography, histologic analysis, and biochemical markers were used to evaluate the bone response. The stress/chewing group exhibited significantly attenuated stress-induced increases in serum corticosterone levels, suppressed bone formation, enhanced bone resorption, and decreased trabecular bone mass in the vertebrae and distal femurs, compared with mice in the stress group. Active mastication during exposure to chronic stress alleviated chronic stress-induced bone density loss in B6 mice. Active mastication during chronic psychologic stress may thus be an effective strategy to prevent and/or treat chronic stress-related osteopenia.

  6. Effects of Hydroxyapatite on Bone Graft Resorption in an Experimental Model of Maxillary Alveolar Arch Defects

    Directory of Open Access Journals (Sweden)

    Ozgur Pilanci

    2013-06-01

    Full Text Available Most commonly used treatments use autologous bone grafts to address bony defects in patients with cleft palate. Major disadvantages of autogenous bone grafts include donor site morbidity and resorption. Suggestions to overcome such problems include biomaterials that can be used alone or in combination with bone. We examined the effect of hydroxyapatite cement on bone graft resorption in a rabbit maxillary alveolar defect model. We divided 16 young adult albino New Zealand rabbits into two groups. A defect 1 cm wide was created in each rabbit's maxillary arch. In Group 1, the removed bone was disrupted, and the pieces were replaced in the defect. In the other group, the pieces were replaced after mixing (1:1 with hydroxyapatite cement. Quantitative computed tomographic evaluation of these grafts was performed in axial and coronal planes for each rabbit at 2 and 12 weeks. In axial images at 12 weeks, the group without cement showed mean bone resorption of 15%. In the cement group, a mean volumetric increase of 68% was seen. No resorption occurred when bone grafts were mixed with hydroxyapatite cement. [Arch Clin Exp Surg 2013; 2(3.000: 170-175

  7. Discordant effect of body mass index on bone mineral density and speed of sound

    Directory of Open Access Journals (Sweden)

    Hagag Philippe

    2003-07-01

    Full Text Available Abstract Background Increased BMI may affect the determination of bone mineral density (BMD by dual X-ray absorptiometry (DXA and speed of sound (SOS measured across bones. Preliminary data suggest that axial SOS is less affected by soft tissue. The purpose of this study is to evaluate the effect of body mass index (BMI on BMD and SOS measured along bones. Methods We compared axial BMD determined by DXA with SOS along the phalanx, radius and tibia in 22 overweight (BMI > 27 kg/m2, and 11 lean (BMI = 21 kg/m2 postmenopausal women. Serum bone specific alkaline phosphatase and urinary deoxypyridinoline excretion determined bone turnover. Results Mean femoral neck – but not lumbar spine BMD was higher in the overweight – as compared with the lean group (0.70 ± 0.82, -0.99 ± 0.52, P P Conclusions The high BMI of postmenopausal women may result in spuriously high BMD. SOS measured along bones may be a more appropriate means for evaluating bones of overweight women.

  8. Effect of the cortex on ultrasonic backscatter measurements of cancellous bone

    International Nuclear Information System (INIS)

    Hoffmeister, Brent K; Holt, Andrew P; Kaste, Sue C

    2011-01-01

    Ultrasonic backscatter techniques offer a promising new approach for detecting changes in bone caused by osteoporosis. However, several challenges impede clinical implementation of backscatter techniques. This study examines how the dense outer surface of bone (the cortex) affects backscatter measurements of interior regions of porous (cancellous) bone tissue. Fifty-two specimens of bone were prepared from 13 human femoral heads so that the same region of cancellous bone could be ultrasonically interrogated through the cortex or along directions that avoided the cortex. Backscatter signals were analyzed over a frequency range of 0.8-3.0 MHz to determine two ultrasonic parameters: apparent integrated backscatter (AIB) and frequency slope of apparent backscatter (FSAB). The term 'apparent' means that the parameters are sensitive to the frequency-dependent effects of diffraction and attenuation. Significant (p < 0.001) changes in AIB and FSAB indicated that measurements through the cortex decreased the apparent backscattered power and increased the frequency dependence of the power. However, the cortex did not affect the correlation of AIB and FSAB with the x-ray bone mineral density of the specimens. This suggests that results from many previous in vitro backscatter studies of specimens of purely cancellous bone may be extrapolated with greater confidence to in vivo conditions.

  9. Effects of dietary bread crust Maillard reaction products on calcium and bone metabolism in rats.

    Science.gov (United States)

    Roncero-Ramos, Irene; Delgado-Andrade, Cristina; Haro, Ana; Ruiz-Roca, Beatriz; Morales, Francisco J; Navarro, María Pilar

    2013-06-01

    Maillard reaction products (MRP) consumption has been related with the development of bone degenerative disorders, probably linked to changes in calcium metabolism. We aimed to investigate the effects of MRP intake from bread crust on calcium balance and its distribution, and bone metabolism. During 88 days, rats were fed control diet or diets containing bread crust as source of MRP, or its soluble high molecular weight, soluble low molecular weight or insoluble fractions (bread crust, HMW, LMW and insoluble diets, respectively). In the final week, a calcium balance was performed, then animals were sacrified and some organs removed to analyse calcium levels. A second balance was carried out throughout the experimental period to calculate global calcium retention. Biochemical parameters and bone metabolism markers were measured in serum or urine. Global calcium bioavailability was unmodified by consumption of bread crust or its isolate fractions, corroborating the previously described low affinity of MRP to bind calcium. Despite this, a higher calcium concentration was found in femur due to smaller bones having a lower relative density. The isolate consumption of the fractions altered some bone markers, reflecting a situation of increased bone resorption or higher turnover; this did not take place in the animals fed the bread crust diet. Thus, the bread crust intake does not affect negatively calcium bioavailability and bone metabolism.

  10. EFFECTS OF TAEKWONDO TRAINING ON BONE MINERAL DENSITY OF HIGH SCHOOL GIRLS IN KOREA

    Directory of Open Access Journals (Sweden)

    S. Young Ho

    2011-09-01

    Full Text Available The incidence of bone fractures has increased in the current decade due to osteoporosis. Bone mineral density (BMD, or the amount of mineralized bone, is an important determinant of risk for bone fractures. Bone mineralization is strongly stimulated by weight-bearing exercise during growth and development. Taekwondo, a Korean martial art, is a well-known form of strenuous and weight-bearing physical activity. Therefore, the primary goal of this study was to determine the effects of taekwondo training on the bone health of female high school students in Korea. The secondary goal of this study was to clarify the relationships between body weight and BMD in this sample. Thirty taekwondo players (TKD and 30 sedentary high school girls (CON voluntarily participated in the present study and were split into three groups by weight: light weight (L under 51 kg; middle weight (M between 51 and under 57 kg; and heavy weight (H over 57 kg. BMD was determined from dual-emission X-ray absorptiometry (DEXA, and percent body fat was measured by the skin-fold method. Lumbar spine and femoral BMD were not significantly different between light, middle and heavy body weight groups. However, the average BMD in the TKD group was significantly greater than in the CON group for all lumbar spine regions (P<0.05. The results of this study suggest that taekwondo training during growth significantly improved bone health in all weight groups.

  11. Total bone calcium in normal women: effect of age and menopause status

    International Nuclear Information System (INIS)

    Gallagher, J.C.; Goldgar, D.; Moy, A.

    1987-01-01

    Bone density in different regions of the skeleton was measured in 392 normal women aged 20-80 years by dual photon absorpiometry. In premenopausal women, aged 25-50 years, multiple regression analysis of regional bone density on age, height, and weight showed a small significant decrease in total bone density (less than 0.01) but no significant change in other regions of the skeleton. In postmenopausal women there were highly significant decreases in all regions of the skeleton (p less than 0.001), and bone density in these areas decreased as a logarithmic function of years since menopause. Based on multiple regression analyses, the decrease in spine density and total bone calcium was 2.5-3.0 times greater in the 25 years after menopause than the 25 years before menopause. The largest change, however, occurred in the first five years after menopause. During this time the estimated annual change in spine density and total bone calcium was about 10 times greater than that in the premenopausal period. These results demonstrate the important effect of the menopause in determining bone mass in later life

  12. Effect of the cortex on ultrasonic backscatter measurements of cancellous bone

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmeister, Brent K; Holt, Andrew P [Department of Physics, Rhodes College, Memphis, TN (United States); Kaste, Sue C, E-mail: hoffmeister@rhodes.edu [Department of Diagnostic Imaging, St Jude Children' s Research Hospital, Memphis, TN (United States)

    2011-10-07

    Ultrasonic backscatter techniques offer a promising new approach for detecting changes in bone caused by osteoporosis. However, several challenges impede clinical implementation of backscatter techniques. This study examines how the dense outer surface of bone (the cortex) affects backscatter measurements of interior regions of porous (cancellous) bone tissue. Fifty-two specimens of bone were prepared from 13 human femoral heads so that the same region of cancellous bone could be ultrasonically interrogated through the cortex or along directions that avoided the cortex. Backscatter signals were analyzed over a frequency range of 0.8-3.0 MHz to determine two ultrasonic parameters: apparent integrated backscatter (AIB) and frequency slope of apparent backscatter (FSAB). The term 'apparent' means that the parameters are sensitive to the frequency-dependent effects of diffraction and attenuation. Significant (p < 0.001) changes in AIB and FSAB indicated that measurements through the cortex decreased the apparent backscattered power and increased the frequency dependence of the power. However, the cortex did not affect the correlation of AIB and FSAB with the x-ray bone mineral density of the specimens. This suggests that results from many previous in vitro backscatter studies of specimens of purely cancellous bone may be extrapolated with greater confidence to in vivo conditions.

  13. Effects of 15 Gy 137Cs γ-rays radiation of rat kidneys on bone metabolism

    International Nuclear Information System (INIS)

    Gao Linfeng; Wang Hongfu; Xu Peikang; Xu Aihong; Zhu Feipeng

    2003-01-01

    The work was to observe the effects of γ-rays radiation of rat kidneys on rat bone metabolism. Ten male SD rats aged 6 months were irradiated at their kidneys with 15 Gy 137 Cs γ-rays (0.91 Gy/min) and were raised for 3 months after the radiation. On collecting 24h urine of rats they were sacrificed for serum, kidney, spine, femur and tibia exams. Results show that the γ-ray irradiation could induce the pathological injuries of renal glomeruli, tubules and mesenchyme. Comparing to the control group, significant changes were found in the irradiated group in terms of their blood urea, nitrogen creatinine, urinal β-2 microglobulin, serum Ca and P, urine Ca and P, activity of serum alkaline phosphatase, 1,25 (OH) 2 D 3 , serum PTH, urine PYD/creatinine, bone mineral density (BMD) of lumbar vertebras, mineral mass of No.4 lumbar vertebra, BMD, dehydrated weight and ash weight of right femur. Marked changes were also found in bone trabecula volume, average bone trabecula thick and the ratio of nodes/points, and rate of mineralization deposition. It was concluded that renal dysfunction and metabolic bone disease might occur with the character of accelerated bone turnover and decreased bone mass

  14. Combined Effects of Spaceflight and Age in Astronauts as Assessed by Areal Bone Mineral Density [BMD] and Trabecular Bone Score

    Science.gov (United States)

    Sibonga, Jean D.; Spector, Elizabeth R.; Ploutz-Snyder, R.; Evans, H. J.; King, L.; Watts, N. B.; Hans, D.; Smith, S. A.

    2013-01-01

    Spaceflight is a potential risk factor for secondary osteoporosis in astronauts. Although lumbar spine (LS) BMD declines rapidly, more than expected for age, there have been no fragility fractures in astronauts that can clearly be attributed to spaceflight. Recently, astronauts have been returning from 6-month spaceflights with absolute BMD still above young adult mean BMD. In spite of these BMD measurements, we project that the rapid loss in bone mass over long-duration spaceflight affects the bone microarchitecture of the LS which might predispose astronauts to premature vertebral fractures. Thus, we evaluated TBS, a novel texture index correlated with vertebral bone microarchitecture, as a means of monitoring changes to bone microarchitecture in astronauts as they age. We previously reported that TBS detects an effect of spaceflight (6-month duration), independent of BMD, in 51 astronauts (47+/-4 y) (Smith et al, J Clin Densitometry 2014). Hence, TBS was evaluated in serial DXA scans (Hologic Discovery W) conducted triennially in all active and retired astronauts and more frequently (before spaceflight, after spaceflight and until recovery) in the subset of astronauts flying 4-6- month missions. We used non-linear models to describe trends in observations (BMD or TBS) plotted as a function of astronaut age. We fitted 1175 observations of 311 astronauts, pre-flight and then postflight starting 3 years after landing or after astronaut's BMD for LS was restored to within 2% of preflight BMD. Observations were then grouped and defined as follows: 1) LD: after exposure to at least one long-duration spaceflight > 100 days and 2) SD: before LD and after exposure to at least one short-duration spaceflight < 30 days. Data from males and females were analyzed separately. Models of SD observations revealed that TBS and BMD had similar curvilinear declines with age for both male and female astronauts. However, models of LD observations showed TBS declining with age while

  15. Combined effects of soy isoflavone and fish oil on ovariectomy-induced bone loss in mice.

    Science.gov (United States)

    Uchida, Raina; Chiba, Hiroshige; Ishimi, Yoshiko; Uehara, Mariko; Suzuki, Kazuharu; Kim, Hyounju; Matsumoto, Akiyo

    2011-07-01

    Both soy isoflavone and n-3 polyunsaturated fatty acids are known to reduce the levels of bone-resorbing cytokines; however, the synergistic effects of these food ingredients have not been examined yet. This study was performed to elucidate the effect of concomitant intake of soy isoflavone and fish oil on bone mass in ovariectomized mice. Eight-week-old ddY female mice were subjected to ovariectomy (OVX) or sham surgery, and then fed an AIN-93G with safflower oil (So) as a control lipid source, isoflavone-supplemented safflower oil (So + I), fish oil instead of safflower oil (Fo) or isoflavone-supplemented fish oil (Fo + I) for 4 weeks. Femoral bone mineral density was significantly decreased by OVX; however, this decrease was inhibited by the intake of isoflavone and/or fish oil. Histomorphometric analyses showed that bone volume and trabecular thickness in the distal femoral trabecular bone were significantly lower in the So group than in the sham group, but those were restored in the Fo + I groups. The number of osteoclasts was significantly decreased by isoflavone intake. The increased rate of bone resorption after OVX was inhibited by isoflavone and/or fish oil. The serum concentration of tumor necrosis factor alpha was increased after OVX, but was significantly lower with the combination of isoflavone with fish oil than isoflavone or fish oil alone. The results of this study indicated that the intakes of soy isoflavone and/or fish oil might have ameliorating effects on bone loss due to OVX. Further, the concomitant intake of soy isoflavone and fish oil at a low dose showed better effects on cytokines related with bone resorption.

  16. Effects of Initial Seeding Density and Fluid Perfusion Rate on Formation of Tissue-Engineered Bone

    OpenAIRE

    GRAYSON, WARREN L.; BHUMIRATANA, SARINDR; CANNIZZARO, CHRISTOPHER; CHAO, P.-H. GRACE; LENNON, DONALD P.; CAPLAN, ARNOLD I.; VUNJAK-NOVAKOVIC, GORDANA

    2008-01-01

    We describe a novel bioreactor system for tissue engineering of bone that enables cultivation of up to six tissue constructs simultaneously, with direct perfusion and imaging capability. The bioreactor was used to investigate the relative effects of initial seeding density and medium perfusion rate on the growth and osteogenic differentiation patterns of bone marrow–derived human mesenchymal stem cells (hMSCs) cultured on three-dimensional scaffolds. Fully decellularized bovine trabecular bon...

  17. The effect of dietary inclusion of meat and bone meal on the ...

    African Journals Online (AJOL)

    The effect of the inclusion of meat and bone meal (MBM) in the diet of old laying hens on their egg production and the quality of their eggs was investigated. Meat and bone meal containing a high concentration of ash and a low concentration of crude protein was included at levels of 2.0, 4.0 and 6.0% in the diets and fed for ...

  18. Collagen type I from bovine bone. Effect of animal age, bone anatomy and drying methodology on extraction yield, self-assembly, thermal behaviour and electrokinetic potential.

    Science.gov (United States)

    Ferraro, Vincenza; Gaillard-Martinie, Brigitte; Sayd, Thierry; Chambon, Christophe; Anton, Marc; Santé-Lhoutellier, Véronique

    2017-04-01

    Natural collagen is easily available from animal tissues such as bones. Main limitations reported in the use of natural collagen are heterogeneity and loss of integrity during recovery. However, its natural complexity, functionality and bioactivity still remain to be achieved through synthetic and recombinant ways. Variability of physicochemical properties of collagen extracted from bovine bone by acetic acid was then investigated taking into account endogenous and exogenous factors. Endogenous: bovine's bones age (4 and 7 years) and anatomy (femur and tibia); exogenous: thermal treatments (spray-drying and lyophilisation). Scanning electron microscopy, spectroscopy (EDS, FTIR, UV/Vis and CD), differential scanning calorimetry (DSC), centesimal composition, mass spectrometry, amino acids and zeta-potential analysis were used for the purpose. Age correlated negatively with yield of recovery and positively with minerals and proteoglycans content. Comparing the anatomy, higher yields were found for tibias, and higher stability of tibias collagen in solution was noticed. Whatever the age and the anatomy, collagens were able to renature and to self-assemble into tri-dimensional structures. Nonetheless thermal stability and kinetics of renaturation were different. Variability of natural collagen with bone age and anatomy, and drying methodology, may be a crucial advantage to conceive tailor-made applications in either the biological or technical sector. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Assessing and reporting heterogeneity in treatment effects in clinical trials: a proposal

    Directory of Open Access Journals (Sweden)

    Kent David M

    2010-08-01

    Full Text Available Abstract Mounting evidence suggests that there is frequently considerable variation in the risk of the outcome of interest in clinical trial populations. These differences in risk will often cause clinically important heterogeneity in treatment effects (HTE across the trial population, such that the balance between treatment risks and benefits may differ substantially between large identifiable patient subgroups; the "average" benefit observed in the summary result may even be non-representative of the treatment effect for a typical patient in the trial. Conventional subgroup analyses, which examine whether specific patient characteristics modify the effects of treatment, are usually unable to detect even large variations in treatment benefit (and harm across risk groups because they do not account for the fact that patients have multiple characteristics simultaneously that affect the likelihood of treatment benefit. Based upon recent evidence on optimal statistical approaches to assessing HTE, we propose a framework that prioritizes the analysis and reporting of multivariate risk-based HTE and suggests that other subgroup analyses should be explicitly labeled either as primary subgroup analyses (well-motivated by prior evidence and intended to produce clinically actionable results or secondary (exploratory subgroup analyses (performed to inform future research. A standardized and transparent approach to HTE assessment and reporting could substantially improve clinical trial utility and interpretability.

  20. The effects of photobiomodulation on healing of bone defects in streptozotocin induced diabetic rats

    Science.gov (United States)

    Martinez Costa Lino, Maíra D.; Bastos de Carvalho, Fabíola; Ferreira Moraes, Michel; Augusto Cardoso, José; Pinheiro, Antônio L. B.; Maria Pedreira Ramalho, Luciana

    2011-03-01

    Previous studies have shown positive effects of Low level laser therapy (LLLT) on the repair of bone defects, but there are only a few that associates bone healing in the presence of a metabolic disorder as Diabetes Melitus and LLLT. The aim of this study was to assess histologically the effect of LLLT (AsGaAl), 780nm, 70mW, CW, Ø~0.4mm, 16J/cm2 per session) on the repair of surgical defects created in the femur of diabetic and non-diabetic Wistar Albinus rats. Surgical bone defects were created in 60 animals divided into four groups of 15 animals each: Group C (non-diabetic - control); Group CL (non-diabetic + LLLT); Group CD (diabetic); Group CDL (diabetic + LLLT). The animals on the irradiated group received 16 J/cm2 per session divided into four points around the defect, being the first irradiation immediately after surgery and repeated every 48h for 14 days. The animals were killed 15, 21 and 30 days after surgery. The results of the present investigation showed histological evidence of improved amount of collagen fibers at early stages of the bone healing (15 days) and increased amount of well organized bone trabeculae at the end of the experimental period (30 days) on irradiated animals, (diabetic and non-diabetic) compared to non irradiated ones. It is concluded that LLLT has a positive biomodulative effect on the healing process of bone defects, even when diabetes mellitus was present.

  1. Growth hormone effects on cortical bone dimensions in young adults with childhood-onset growth hormone deficiency

    DEFF Research Database (Denmark)

    Hyldstrup, L; Conway, G S; Racz, K

    2012-01-01

    Growth hormone (GH) treatment in young adults with childhood-onset GH deficiency has beneficial effects on bone mass. The present study shows that cortical bone dimensions also benefit from GH treatment, with endosteal expansion and increased cortical thickness leading to improved bone strength....... INTRODUCTION: In young adults with childhood-onset growth hormone deficiency (CO GHD), GH treatment after final height is reached has been shown to have beneficial effects on spine and hip bone mineral density. The objective of the study was to evaluate the influence of GH on cortical bone dimensions. METHODS...

  2. Effects of the Heterogeneity in the Electron Beam Welded Joint on Mechanical Properties of Ti6Al4V Alloy

    Science.gov (United States)

    Liu, Jing; Gao, Xiao-Long; Zhang, Lin-Jie; Zhang, Jian-Xun

    2015-01-01

    The aim of this investigation was to evaluate the effect of microstructure heterogeneity on the tensile and low cycle fatigue properties of electron beam welded (EBW) Ti6Al4V sheets. To achieve this goal, the tensile and low cycle fatigue property in the EBW joints and base metal (BM) specimens is compared. During the tensile testing, digital image correlation technology was used to measure the plastic strain field evolution within the specimens. The experimental results showed that the tensile ductility and low cycle fatigue strength of EBW joints are lower than that of BM specimens, mainly because of the effect of microstructure heterogeneity of the welded joint. Moreover, the EBW joints exhibit the cyclic hardening behavior during low fatigue process, while BM specimens exhibit the cyclic softening behavior. Compared with the BM specimens with uniform microstructure, the heterogeneity of microstructure in the EBW joint is found to decrease the mechanical properties of welded joint.

  3. Comparative effectiveness of using resorbable membranes of polylactic acid and collagen in regeneration of bone defects in patients with periimplantitis

    Directory of Open Access Journals (Sweden)

    Gudaryan A.A.

    2014-03-01

    Full Text Available The article presents the results of comparative study of effectiveness of usage of separation membranes from polylactic acid (PLA and collagen in carrying out targeted regeneration of bone tissue in 22 patients with periimplantitis. Purpose: To conduct a comparative clinico-radiological efficiency of PLA membrane and collagen membranes in removing bone defects of the alveolar bone in patients with periimplantitis in clinic. It was found that depending on the type of membrane, bone tissue growth occurs not in the same way. Surgery in treatment of periimplantitis using osteo-inducing agent «Bio-Oss» and PLA membranes allows to reach full recovery of bone in bone defects in 90.9 % of patients versus 63.63 % of cases with collagen membranes. Thus, reconstitution of bone in bone defects in periimplantitis is more of full value in using PLA membranes than with membranes from collagen.

  4. Effect of Silicon Supplementation on Bone Status in Ovariectomized Rats Under Calcium-Replete Condition.

    Science.gov (United States)

    Bu, So Young; Kim, Mi-Hyun; Choi, Mi-Kyeong

    2016-05-01

    Previous studies have suggested that silicon (Si) had positive effects on bone, but such benefits from Si may be dependent on calcium status. Also, several biochemical roles of Si in osteoblastic mineralization, the regulation of gene expression related to bone matrix synthesis, and the decrease in reactive oxygen species and pro-inflammatory mediators were reported, but these effects were mostly shown in cell culture studies. Hence, we tested the effect of Si supplementation on bone status and the gene expression related to bone metabolism and inflammatory mediators in young estrogen-deficient rats under calcium-replete condition (0.5 % diet). Results showed that 15-week supplementation of both high and very high doses of Si (0.025 and 0.075 % diet, respectively) could not restore the ovariectomy (OVX)-induced decrease of bone mineral density (BMD) of vertebrae, femur, and tibia. Also, several bone biochemical markers (ALP, osteocalcin, CTx) and mRNA expression of COL-I, RANKL, IL-6, and TNF-α in femur metaphysis were not significantly changed by Si in OVX rats. However, a very high dose (0.075 %) of Si supplementation significantly increased OPG expression and decreased the ratio of RANKL/OPG in mRNA expression comparable to that of sham-control animals. Taken together, Si supplementation did not increase BMD under calcium-replete condition but the decrease in the ratio of RANKL/OPG expression to the normal level suggests the possibility of a bone health benefit of Si in estrogen deficiency-induced bone loss.

  5. Reconstructive Effects of Percutaneous Electrical Stimulation Combined with GGT Composite on Large Bone Defect in Rats

    Directory of Open Access Journals (Sweden)

    Bo-Yin Yang

    2013-01-01

    Full Text Available Previous studies have shown the electromagnetic stimulation improves bone remodeling and bone healing. However, the effect of percutaneous electrical stimulation (ES was not directly explored. The purpose of this study was to evaluate effect of ES on improvement of bone repair. Twenty-four adult male Sprague-Dawley rats were used for cranial implantation. We used a composite comprising genipin cross-linked gelatin mixed with tricalcium phosphate (GGT. Bone defects of all rats were filled with the GGT composites, and the rats were assigned into six groups after operation. The first three groups underwent 4, 8, and 12 weeks of ES, and the anode was connected to the backward of the defect on the neck; the cathode was connected to the front of the defect on the head. Rats were under inhalation anesthesia during the stimulation. The other three groups only received inhalation anesthesia without ES, as control groups. All the rats were examined afterward at 4, 8, and 12 weeks. Radiographic examinations including X-ray and micro-CT showed the progressive bone regeneration in the both ES and non-ES groups. The amount of the newly formed bone increased with the time between implantation and examination in the ES and non-ES groups and was higher in the ES groups. Besides, the new bone growth trended on bilateral sides in ES groups and accumulated in U-shape in non-ES groups. The results indicated that ES could improve bone repair, and the effect is higher around the cathode.

  6. Further studies on the intermediary metabolism of bone in vitro and a monoclonal cell line (MMB-1) derived from bone: effects of parathyroid hormone and acetazolamide

    International Nuclear Information System (INIS)

    Nichols, F.C.

    1981-01-01

    The mechanism/mechanisms by which PTH affects Ca homeostasis between blood and bone have not been clearly established. Most studies of metabolic acid production in bone took place during the late 1950s and early 1960s. Since that time, assay techniques for metabolic acid production have been improved for greater sensitivity, more has been learned as to how PTH mediates its cellular responses, and techniques for cell isolation and culture have dramatically improved. These improvements have made possible new approaches to the study of short term effects of PTH on metabolic acid production in bone. Chapter 1 explores the potential of bone to utilize substrates other than glucose for metabolic energy transfer. Chapter 2 characterizes glucose metabolism in mouse calvaria in vitro and explores effects of PTH, acetazolamide, and C1 13,850 on calvaria oxidative metabolism. Chapter 3 describes PTH effects on glucose metabolism of MMB-1 cells, a monoclonal cell line reported to possess osteoblast-like characteristics

  7. 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.......01). Furthermore, AKG administration induced significantly higher bone mineral density of the cortical bone by 7.1% (P

  8. Correction of metabolic acidosis with potassium citrate in renal transplant patients and its effect on bone quality.

    Science.gov (United States)

    Starke, Astrid; Corsenca, Alf; Kohler, Thomas; Knubben, Johannes; Kraenzlin, Marius; Uebelhart, Daniel; Wüthrich, Rudolf P; von Rechenberg, Brigitte; Müller, Ralph; Ambühl, Patrice M

    2012-09-01

    Acidosis and transplantation are associated with increased risk of bone disturbances. This study aimed to assess bone morphology and metabolism in acidotic patients with a renal graft, and to ameliorate bone characteristics by restoration of acid/base homeostasis with potassium citrate. This was a 12-month controlled, randomized, interventional trial that included 30 renal transplant patients with metabolic acidosis (S-[HCO(3)(-)] 24 mmol/L, or potassium chloride (control group). Iliac crest bone biopsies and dual-energy X-ray absorptiometry were performed at baseline and after 12 months of treatment. Bone biopsies were analyzed by in vitro micro-computed tomography and histomorphometry, including tetracycline double labeling. Serum biomarkers of bone turnover were measured at baseline and study end. Twenty-three healthy participants with normal kidney function comprised the reference group. Administration of potassium citrate resulted in persisting normalization of S-[HCO(3)(-)] versus potassium chloride. At 12 months, bone surface, connectivity density, cortical thickness, and cortical porosity were better preserved with potassium citrate than with potassium chloride, respectively. Serological biomarkers and bone tetracycline labeling indicate higher bone turnover with potassium citrate versus potassium chloride. In contrast, no relevant changes in bone mineral density were detected by dual-energy X-ray absorptiometry. Treatment with potassium citrate in renal transplant patients is efficient and well tolerated for correction of metabolic acidosis and may be associated with improvement in bone quality. This study is limited by the heterogeneity of the investigated population with regard to age, sex, and transplant vintage.

  9. Effects of long-term estrogen replacement therapy on bone turnover in periarticular tibial osteophytes in surgically postmenopausal cynomolgus monkeys.

    Science.gov (United States)

    Olson, Erik J; Lindgren, Bruce R; Carlson, Cathy S

    2008-05-01

    The aims of the present study were to assess the effects of long-term estrogen replacement therapy (ERT) on size and indices of bone turnover in periarticular osteophytes in ovariectomized cynomolgus monkeys and to compare dynamic indices of bone turnover in osteophyte bone with those of subchondral bone (SCB) and epiphyseal/metaphyseal cancellous (EMC) bone. One hundred sixty-five adult female cynomolgus macaques were bilaterally ovariectomized and randomly divided into three age- and weight-matched treatment groups for a 36-month treatment period. Group 1 (OVX control) received no treatment, Group 2 (SPE) received soy phytoestrogens, and Group 3 (ERT) received conjugated equine estrogens in the diet; all monkeys were labeled with calcein before necropsy. A midcoronal, plastic-embedded section of the right proximal tibia from 20 randomly selected animals per treatment group was examined histologically. Forty-nine of the sections (OVX control, n=16; SPE, n=16; ERT, n=17) contained lateral abaxial osteophytes, and static and dynamic histomorphometry measurements were taken from osteophyte bone, SCB from the lateral tibial plateau, and EMC bone. Data were analyzed using the ANOVA and Kruskal-Wallis test, correlation and regression methods, and the Friedman and Wilcoxon signed rank test. There was no significant effect of long-term ERT on osteophyte area or on any static or dynamic histomorphometry parameters. The bone volume, trabecular number, and trabecular thickness in osteophyte bone were considerably higher than in EMC bone; whereas, trabecular separation was considerably lower in osteophyte bone. In all three treatment groups, BS/BV was significantly lower in osteophyte bone vs. EMC bone and significantly higher in osteophyte bone vs. lateral SCB. We conclude that osteophyte area and static and dynamic histomorphometry parameters within periarticular tibial osteophytes in ovariectomized cynomolgus monkeys are not significantly influenced by long-term ERT, but

  10. Effects of long-term estrogen replacement therapy on bone turnover in periarticular tibial osteophytes in surgically postmenopausal cynomolgus monkeys

    Science.gov (United States)

    Olson, Erik J.; Lindgren, Bruce R.; Carlson, Cathy S.

    2008-01-01

    The aims of the present study were to assess the effects of long-term estrogen replacement therapy (ERT) on size and indices of bone turnover in periarticular osteophytes in ovariectomized cynomolgus monkeys and to compare dynamic indices of bone turnover in osteophyte bone with those of subchondral bone (SCB) and epiphyseal/metaphyseal cancellous (EMC) bone. One hundred sixty-five adult female cynomolgus macaques were bilaterally ovariectomized and randomly divided into three age- and weight-matched treatment groups for a 36-month treatment period. Group 1 (OVX control) received no treatment, Group 2 (SPE) received soy phytoestrogens, and Group 3 (ERT) received conjugated equine estrogens in the diet; all monkeys were labeled with calcein before necropsy. A midcoronal, plastic-embedded section of the right proximal tibia from 20 randomly selected animals per treatment group was examined histologically. Forty-nine of the sections (OVX control, n=16; SPE, n=16; ERT, n=17) contained lateral abaxial osteophytes, and static and dynamic histomorphometry measurements were taken from osteophyte bone, SCB from the lateral tibial plateau, and EMC bone. Data were analyzed using the ANOVA and Kruskal-Wallis test, correlation and regression methods, and the Friedman and Wilcoxon signed rank test. There was no significant effect of long-term ERT on osteophyte area or on any static or dynamic histomorphometry parameters. The bone volume, trabecular number, and trabecular thickness in osteophyte bone were considerably higher than in EMC bone; whereas, trabecular separation was considerably lower in osteophyte bone. In all three treatment groups, BS/BV was significantly lower in osteophyte bone vs. EMC bone and significantly higher in osteophyte bone vs. lateral SCB. We conclude that osteophyte area and static and dynamic histomorphometry parameters within periarticular tibial osteophytes in ovariectomized cynomolgus monkeys are not significantly influenced by long-term ERT, but

  11. Estrogen inhibits Dlk1/FA1 production: A potential mechanism for estrogen effects on bone turnover

    DEFF Research Database (Denmark)

    Abdallah, Basem M; Bay-Jensen, Anne-Christine; Srinivasan, Bhuma

    2011-01-01

    We have recently identified delta-like 1/fetal antigen 1 (Dlk1/FA1) as a novel regulator of bone mass that functions to mediate bone loss under estrogen deficiency in mice. In this report, we investigated the effects of estrogen (E) deficiency and E replacement on serum (s) levels of Dlk1/FA1 (s......-Dlk1FA1) and its correlation with bone turnover markers. s-Dlk1/FA1 and bone turnover markers (serum cross-linked C-telopeptide [s-CTX] and serum osteocalcin) were measured in two cohorts: a group of pre- and postmenopausal women (n = 100) and a group of postmenopausal women, where half had received...... estrogen-replacement therapy (ERT, n = 166). s-Dlk1/FA1 and s-CTX were elevated in postmenopausal E-deficient women compared with premenopausal E-replete women (both p ...

  12. Effect of castration age on weight and size of some bones in Piemontese male cattle

    Directory of Open Access Journals (Sweden)

    C. Lazzaroni

    2010-04-01

    Full Text Available Effect of pre- and post-pubertal castration on bone weight and measurements has been studied in 3 groups of Piemontese male cattle (EC - early castrated, LC - late castrated, IM - intact reared in the same environmental conditions and slaughtered at about 18 month of age, at about 550 kg of l.w., and at the same commercial fattening degree. At side commercial dissection all separated bones were weighted, and on the main ones (scapula, humerus, radius, femur, and tibia linear measures were recorded and then some conformation ratios were calculated (weight/length, length/width, and length/circumference. Data were analysed by GLM ANCOVA procedure, correcting data on side weight to avoid bias due to differences in carcass weight. No differences were found in side bone weight (23.58 ± 2.61 kg, so as in single bone weight, measures and ratios.

  13. Effect of occlusal (mechanical) stimulus on bone remodelling in rat mandibular condyle.

    Science.gov (United States)

    Gazit, D; Ehrlich, J; Kohen, Y; Bab, I

    1987-09-01

    Mechanical load influences the remodelling of skeletal tissues. In the mandibular condyle, occlusal alterations and the consequent mechanical stimulus induce changes in chondrocytes and cartilage mineralization. In the present study we quantified in the mandibular condyle the effect of occlusal interference on remodelling of the subchondral bone. Computerized histomorphometry after 5-21-day exposure to the influence of a unilateral occlusal splint revealed an increased rate of trabecular remodelling, consisting of enhancement in osteoblast and osteoclast numbers and activities. The bone formation parameters reached their high values on Days 5 or 9 and remained stable thereafter. Bone resorption showed a gradual increase throughout the experimental period. These results further characterize the temporomandibular joint reaction to occlusal alterations. It is suggested that the present increase in bone turnover together with the known enhancement in chondrogenesis are part of a process of functional adaptation in response to mechanical stimulus.

  14. Artistic versus rhythmic gymnastics: effects on bone and muscle mass in young girls.

    Science.gov (United States)

    Vicente-Rodriguez, G; Dorado, C; Ara, I; Perez-Gomez, J; Olmedillas, H; Delgado-Guerra, S; Calbet, J A L

    2007-05-01

    We compared 35 prepubertal girls, 9 artistic gymnasts and 13 rhythmic gymnasts with 13 nonphysically active controls to study the effect of gymnastics on bone and muscle mass. Lean mass, bone mineral content and areal density were measured by dual energy X-ray absorptiometry, and physical fitness was also assessed. The artistic gymnasts showed a delay in pubertal development compared to the other groups (partistic gymnasts had a 16 and 17 % higher aerobic power and anaerobic capacity, while the rhythmic group had a 14 % higher anaerobic capacity than the controls, respectively (all partistic gymnasts had higher lean mass (partistic and the rhythmic gymnasts (partistic group compared to the other groups. Lean mass strongly correlated with bone mineral content (r=0.84, partistic gymnastic participation is associated with delayed pubertal development, enhanced physical fitness, muscle mass, and bone density in prepubertal girls, eliciting a higher osteogenic stimulus than rhythmic gymnastic.

  15. Necessity of using heterogeneous ellipsoidal Earth model with terrain to calculate co-seismic effect

    Science.gov (United States)

    Cheng, Huihong; Zhang, Bei; Zhang, Huai; Huang, Luyuan; Qu, Wulin; Shi, Yaolin

    2016-04-01

    Co-seismic deformation and stress changes, which reflect the elasticity of the earth, are very important in the earthquake dynamics, and also to other issues, such as the evaluation of the seismic risk, fracture process and triggering of earthquake. Lots of scholars have researched the dislocation theory and co-seismic deformation and obtained the half-space homogeneous model, half-space stratified model, spherical stratified model, and so on. Especially, models of Okada (1992) and Wang (2003, 2006) are widely applied in the research of calculating co-seismic and post-seismic effects. However, since both semi-infinite space model and layered model do not take the role of the earth curvature or heterogeneity or topography into consideration, there are large errors in calculating the co-seismic displacement of a great earthquake in its impacted area. Meanwhile, the computational methods of calculating the co-seismic strain and stress are different between spherical model and plane model. Here, we adopted the finite element method which could well deal with the complex characteristics (such as anisotropy, discontinuities) of rock and different conditions. We use the mash adaptive technique to automatically encrypt the mesh at the fault and adopt the equivalent volume force replace the dislocation source, which can avoid the difficulty in handling discontinuity surface with conventional (Zhang et al., 2015). We constructed an earth model that included earth's layered structure and curvature, the upper boundary was set as a free surface and the core-mantle boundary was set under buoyancy forces. Firstly, based on the precision requirement, we take a testing model - - a strike-slip fault (the length of fault is 500km and the width is 50km, and the slippage is 10m) for example. Because of the curvature of the Earth, some errors certainly occur in plane coordinates just as previous studies (Dong et al., 2014; Sun et al., 2012). However, we also found that: 1) the co

  16. [Effects of pamidronate disodium (Bonin) combined with chemotherapy on bone pain in multiple myeloma].

    Science.gov (United States)

    Leng, Yun; Chen, Shi-lun; Shi, Hong-zhi

    2002-10-01

    Objective. To evaluate the therapeutic effects of Disodium Pamidronate (Bonin) on bone pain in multiple myeloma. Method. 18 patients received only chemotherapy and 16 patients with addition of Bonin were compared. Result. The bone pain was significantly relieved both in chemotherapy alone group and in the combination group of Bonin with chemotherapy after treatment (P<0.01, as compared with before therapy). However, the effects of combination group were more dramatical than that of the other group (P<0.05). No obvious side-effects were observed except mild fever in one patient in the combination group. Conclusion. Bonin, as a safe and effective Bisphosphonates preparation, could relieve bone pain in multiple myeloma more effectively when combined with chemotherapy.