55 research outputs found

    Inhibitory effect of salmon calcitonin on bone resorption: morphological study of the tibial growth plate in rats.

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    Salmon calcitonin (sCT) at doses of 100 and 50 UI given subcutaneously to growing rats produced in vivo evidence of osteoclastic activity inhibition. Histological assessment was carried out by measuring the perichondrial ring of Lacroix height, and a dose-correlated effect was found. These aspects were coupled with an increase in the osteoclast number and suggested that in studies with bone resorption inhibitors, morphological evaluation based on osteoclasts count is not reliable. The changes of the metaphysis suggested also that sCT affects the activity of hypertrophic chondrocytes of the growth plate. Plasma calcium levels did not differ significantly between treated rats and controls; an increased phosphatemia was observed in sCT-treated animals

    Experimental model in vivo for quantitative assessment of bone resorption inhibition.

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    Quantitative assessment of bone resorption inhibition in vivo is not easily accomplished; methods relying on a count of osteoclasts are questionable, and histomorphometric evaluation of the bone mass presents several technical problems as well. The authors developed a simple method to measure the inhibition of bone resorption by study of the proximal tibial metaphysis of growing rats: the height of the perichondrial bone ring was taken as an index of the balance between osteoblastic and osteoclastic activity because any agent that inhibits osteoclasts (without interference with osteoblasts) produces an increase in the height of this anatomical structure. Since the ring is well demarcated by surrounding tissues, its height can be measured with accuracy and used for quantitative assessment of bone resorption inhibition. This model was tested with salmon calcitonin, and it provides evidence in vivo that this hormone inhibits osteoclastic bone resorption

    Myositis ossificans in the newborn. A case report.

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    Myositis ossificans (MO) and fibroosseous pseudotumor of digits (FP) are pseudotumoral mimics of malignancy. A review of 50 cases of MO and 14 cases of FP showed that a malignant diagnosis was suggested by referring pathologists in 23% of MO and 9% of FP. The most common misdiagnosis was osteosarcoma. Awareness of the spectrum of clinicopathological features of MO and FP will help pathologists avoid misdiagnoses. A comparison of the clinicopathological features of MO and FP showed that most features were similar, but FP involved an older age group (p<0.001). MO showed a statistically significant higher tendency to contain fibrinous material (p=0.007), edematous lymphangioma-like areas (p=0.01 3), and cartilage (p=0.017) and FP to contain excessive immature osteoid (p=0.029). These differences may be related to the site of occurrenc

    Study of the bone pathology in early mucolipidosis II (I-cell disease).

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    Histological examination of the bones obtained on autopsy of a 5-month-old child with mucolipidosis II (I-cell disease) revealed inhibition of the growth plate calcification with defective vascular invasion and signs of hyperparathyroidism. These findings are the chondro-osseous basis of the early radiological ricket-like appearance of bones in the neonatal period or soon thereafter. Whether the early skeletal abnormalities of mucolipidosis II result from a primary enzymatic defect of cartilage and bone cells or from factors controlling bone metabolism deserves further study

    modeling early time dynamics of relativistic heavy ion collisions

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    We studied isotropization and thermalization of the quark-gluon plasma produced by decaying color-electric flux tubes created at the very early stages of relativistic heavy ion collisions. We coupled the dynamical evolution of the initial field, which decays to a plasma by the Schwinger mechanism, to the dynamics of the many particles system produced by the decay. The evolution of such a system is described by relativistic transport theory at fixed values of the viscosity over entropy density ratio. Within a single self-consistent calculation scheme we computed quantities which serve as indicators of the equilibration of the plasma for a 1+1 dimensional expanding geometry. We find that the initial color-electric field decays within 1 fm/c and particles production occurs in less than 1 fm/c; however, in the case of large viscosity oscillations of the field appear along the entire time evolution of the system, affecting also the behaviour of the ratio between longitudinal and transverse pressure. In case of small viscosity we find that the isotropization time is about 0.8 fm/c and the thermalization time is about 1 fm/c, in agreement with the common lore of hydrodynamic approaches

    New method to assess teh pozzolanic reactivity of mineral admixtures by measn of pH and electrical conductivity measurements in lime: pozzolan suspensions

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    A very simple method based on electrical conductivity and pH measurements was proposed for assessing reactivity of pozzolans. Calcium hydroxide:pozzolan water suspensions were monitored by means of measurements of electrical conductivity and pH values. In these suspensions, Ca(OH)2 in solid state was initially present, being them, thus, saturated in this reagent. Three testing temperatures were selected (40, 50 and 60 °C). In the experiments carried out, calcium hydroxide was suspended in deionized water for yielding a lime saturated suspension. The addition of siliceous pozzolan (two types of rice husk ash RHA and two types of densified silica fume DSF were tested) to the saturated lime suspension can produce the unsaturation of the system, depending on the testing time, testing temperature and reactivity of pozzolan. When unsaturation was reached, the loss of electrical conductivity was higher than 30% and the variation of pH was higher than 0.15 units. These threshold values were selected for characterizing the reactivity of pozzolans by means of a proposed template, classifying the pozzolan in three different reactivity levels.Mitsuuchi Tashima, M.; Soriano Martinez, L.; Monzó Balbuena, JM.; Borrachero Rosado, MV.; Akasaki, JL.; Paya Bernabeu, JJ. (2014). New method to assess teh pozzolanic reactivity of mineral admixtures by measn of pH and electrical conductivity measurements in lime: pozzolan suspensions. Materiales de Construcción. 64(316):32-44. doi:10.3989/mc.2014.00914S324464316Schneider, M., Romer, M., Tschudin, M., & Bolio, H. (2011). Sustainable cement production—present and future. Cement and Concrete Research, 41(7), 642-650. doi:10.1016/j.cemconres.2011.03.019Altmann, F., & Mechtcherine, V. (2013). Durability design strategies for new cementitious materials. Cement and Concrete Research, 54, 114-125. doi:10.1016/j.cemconres.2013.08.008Shi, C., Jiménez, A. F., & Palomo, A. (2011). New cements for the 21st century: The pursuit of an alternative to Portland cement. Cement and Concrete Research, 41(7), 750-763. doi:10.1016/j.cemconres.2011.03.0164. Payá, J. (2012) La "transmutación" sostenible de los residuos para nuevas materias primas en el ámbito del concreto. Dyna 79, 38–47.Donatello, S., Freeman-Pask, A., Tyrer, M., & Cheeseman, C. R. (2010). Effect of milling and acid washing on the pozzolanic activity of incinerator sewage sludge ash. Cement and Concrete Composites, 32(1), 54-61. doi:10.1016/j.cemconcomp.2009.09.002Soriano, L., Monzó, J., Bonilla, M., Tashima, M. M., Payá, J., & Borrachero, M. V. (2013). Effect of pozzolans on the hydration process of Portland cement cured at low temperatures. Cement and Concrete Composites, 42, 41-48. doi:10.1016/j.cemconcomp.2013.05.0077. Villar-Coci-a, E.; Frías, M.; Valencia-Morales, E.; Rojas, M.I.S. (2005) Validation of a kinetic-diffusive model to characterize pozzolanic reaction kinetics in sugar cane straw-clay ash/lime systems. Mater. Construcc. 55 [278], 29–40.8. Cruz, J.M.; Payá, J.; Lalinde, L.F.; Fita, I.C. (2011) Evaluation of electric properties of cement mortars containing pozzolans. Mater. Construcc. 61 [301], 7–26.Luxán, M. P., Madruga, F., & Saavedra, J. (1989). Rapid evaluation of pozzolanic activity of natural products by conductivity measurement. Cement and Concrete Research, 19(1), 63-68. doi:10.1016/0008-8846(89)90066-5Payá, J., Borrachero, M. ., Monzó, J., Peris-Mora, E., & Amahjour, F. (2001). Enhanced conductivity measurement techniques for evaluation of fly ash pozzolanic activity. Cement and Concrete Research, 31(1), 41-49. doi:10.1016/s0008-8846(00)00434-8Villar-Cociña, E., Valencia-Morales, E., González-Rodrı́guez, R., & Hernández-Ruı́z, J. (2003). Kinetics of the pozzolanic reaction between lime and sugar cane straw ash by electrical conductivity measurement: A kinetic–diffusive model. Cement and Concrete Research, 33(4), 517-524. doi:10.1016/s0008-8846(02)00998-5Frías, M., Villar-Cociña, E., Sánchez de Rojas, M. I., & Valencia-Morales, E. (2005). The effect that different pozzolanic activity methods has on the kinetic constants of the pozzolanic reaction in sugar cane straw-clay ash/lime systems: Application of a kinetic–diffusive model. Cement and Concrete Research, 35(11), 2137-2142. doi:10.1016/j.cemconres.2005.07.005Sinthaworn, S., & Nimityongskul, P. (2009). Quick monitoring of pozzolanic reactivity of waste ashes. Waste Management, 29(5), 1526-1531. doi:10.1016/j.wasman.2008.11.010Payá, J., Monzó, J., Borrachero, M. ., Mellado, A., & Ordoñez, L. . (2001). Determination of amorphous silica in rice husk ash by a rapid analytical method. Cement and Concrete Research, 31(2), 227-231. doi:10.1016/s0008-8846(00)00466-xMartínez-Velandia, D., Payá, J., Monzó, J., & Borrachero, M. V. (2011). Effect of sonication on the reactivity of silica fume in Portland cement mortars. Advances in Cement Research, 23(1), 23-31. doi:10.1680/adcr.8.00027Tashima, M. M., Fioriti, C. F., Akasaki, J. L., Bernabeu, J. P., Sousa, L. C., & Melges, J. L. P. (2012). Cinza de casca de arroz (CCA) altamente reativa: método de produção e atividade pozolânica. Ambiente Construído, 12(2), 151-163. doi:10.1590/s1678-86212012000200010Payá, J., Monzó, J., Borrachero, M. V., Peris-Mora, E., & Amahjour, F. (2000). Mechanical treatment of fly ashes. Cement and Concrete Research, 30(4), 543-551. doi:10.1016/s0008-8846(00)00218-

    Community shift of ammonia-oxidizing bacteria along an anthropogenic pollution gradient from the Pearl River Delta to the South China Sea

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    The phylogenetic diversity and abundance of ammonia-oxidizing beta-proteobacteria (beta-AOB) was analyzed along an anthropogenic pollution gradient from the coastal Pearl River Delta to the South China Sea using the ammonia monooxygenase subunit A (amoA) gene. Along the gradient from coastal to the open ocean, the phylogenetic diversity of the dominant genus changed from Nitrosomonas to Nitrosospira, indicating the niche specificity by these two genera as both salinity and anthropogenic influence were major factors involved. The diversity of bacterial amoA gene was also variable along the gradient, with the highest in the deep-sea sediments, followed by the marshes sediments and the lowest in the coastal areas. Within the Nitrosomonas-related clade, four distinct lineages were identified including a putative new one (A5-16) from the different sites over the large geographical area. In the Nitrosospira-related clade, the habitat-specific lineages to the deep-sea and coastal sediments were identified. This study also provides strong support that Nitrosomonas genus, especially Nitrosomonas oligotropha lineage (6a) could be a potential bio-indicator species for pollution or freshwater/wastewater input into coastal environments. A suite of statistical analyses used showed that water depth and temperature were major factors shaping the community structure of beta-AOB in this study area

    Institutions for Effective Business-Government Collaboration: Micro Mechanisms and Macro Politics in Latin America

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    Bone marrow granulomas in hairy cell leukaemia

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