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Sample records for properties influence calcification

  1. Determining the influence of calcification on the failure properties of abdominal aortic aneurysm (AAA) tissue.

    PubMed

    O'Leary, Siobhan A; Mulvihill, John J; Barrett, Hilary E; Kavanagh, Eamon G; Walsh, Michael T; McGloughlin, Tim M; Doyle, Barry J

    2015-02-01

    Varying degrees of calcification are present in most abdominal aortic aneurysms (AAAs). However, their impact on AAA failure properties and AAA rupture risk is unclear. The aim of this work is evaluate and compare the failure properties of partially calcified and predominantly fibrous AAA tissue and investigate the potential reasons for failure. Uniaxial mechanical testing was performed on AAA samples harvested from 31 patients undergoing open surgical repair. Individual tensile samples were divided into two groups: fibrous (n=31) and partially calcified (n=38). The presence of calcification was confirmed by fourier transform infrared spectroscopy (FTIR). A total of 69 mechanical tests were performed and the failure stretch (λf), failure stress (σf) and failure tension (Tf) were recorded for each test. Following mechanical testing, the failure sites of a subset of both tissue types were examined using scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) to investigate the potential reasons for failure. It has been shown that the failure properties of partially calcified tissue are significantly reduced compared to fibrous tissue and SEM and EDS results suggest that the junction between a calcification deposit and the fibrous matrix is highly susceptible to failure. This study implicates the presence of calcification as a key player in AAA rupture risk and provides further motivation for the development of non-invasive methods of measuring calcification.

  2. Determining the influence of calcification on the failure properties of abdominal aortic aneurysm (AAA) tissue.

    PubMed

    O'Leary, Siobhan A; Mulvihill, John J; Barrett, Hilary E; Kavanagh, Eamon G; Walsh, Michael T; McGloughlin, Tim M; Doyle, Barry J

    2015-02-01

    Varying degrees of calcification are present in most abdominal aortic aneurysms (AAAs). However, their impact on AAA failure properties and AAA rupture risk is unclear. The aim of this work is evaluate and compare the failure properties of partially calcified and predominantly fibrous AAA tissue and investigate the potential reasons for failure. Uniaxial mechanical testing was performed on AAA samples harvested from 31 patients undergoing open surgical repair. Individual tensile samples were divided into two groups: fibrous (n=31) and partially calcified (n=38). The presence of calcification was confirmed by fourier transform infrared spectroscopy (FTIR). A total of 69 mechanical tests were performed and the failure stretch (λf), failure stress (σf) and failure tension (Tf) were recorded for each test. Following mechanical testing, the failure sites of a subset of both tissue types were examined using scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) to investigate the potential reasons for failure. It has been shown that the failure properties of partially calcified tissue are significantly reduced compared to fibrous tissue and SEM and EDS results suggest that the junction between a calcification deposit and the fibrous matrix is highly susceptible to failure. This study implicates the presence of calcification as a key player in AAA rupture risk and provides further motivation for the development of non-invasive methods of measuring calcification. PMID:25482218

  3. Local influence of calcifications on the wall mechanics of abdominal aortic aneurysm

    NASA Astrophysics Data System (ADS)

    de Putter, Sander; van de Vosse, Frans N.; Breeuwer, Marcel; Gerritsen, Frans A.

    2006-03-01

    Finite element wall stress simulations on patient-specific models of abdominal aortic aneurysm (AAA) may provide a better rupture risk predictor than the currently used maximum transverse diameter. Calcifications in the wall of AAA lead to a higher maximum wall stress and thus may lead to an elevated rupture risk. The reported material properties for calcifications and the material properties actually used for simulations show great variation. Previous studies have focused on simplified modelling of the calcification shapes within a realistic aneurysm shape. In this study we use an accurate representation of the calcification geometry and a simplified model for the AAA. The objective of this approach is to investigate the influence of the calcification geometry, the material properties and the modelling approach for the computed peak wall stress. For four realistic calcification shapes from standard clinical CT images of AAA, we performed simulations with three distinct modelling approaches, at five distinct elasticity settings. The results show how peak wall stress is sensitive to the material properties of the calcifications. For relatively elastic calcifications, the results from the different modelling approaches agree. Also, for relatively elastic calcifications the computed wall stress in the tissue surrounding the calcifications shows to be insensitive to the exact calcification geometry. For stiffer calcifications the different modelling approaches and the different geometries lead to significantly different results. We conclude that an important challenge for future research is accurately estimating the material properties and the rupture potential of the AAA wall including calcifications.

  4. How Does Calcification Influence Plaque Vulnerability? Insights from Fatigue Analysis

    PubMed Central

    Wu, Baijian; Pei, Xuan; Li, Zhi-Yong

    2014-01-01

    Background. Calcification is commonly believed to be associated with cardiovascular disease burden. But whether or not the calcifications have a negative effect on plaque vulnerability is still under debate. Methods and Results. Fatigue rupture analysis and the fatigue life were used to evaluate the rupture risk. An idealized baseline model containing no calcification was first built. Based on the baseline model, we investigated the influence of calcification on rupture path and fatigue life by adding a circular calcification and changing its location within the fibrous cap area. Results show that 84.0% of calcified cases increase the fatigue life up to 11.4%. For rupture paths 10D far from the calcification, the life change is negligible. Calcifications close to lumen increase more fatigue life than those close to the lipid pool. Also, calcifications in the middle area of fibrous cap increase more fatigue life than those in the shoulder area. Conclusion. Calcifications may play a positive role in the plaque stability. The influence of the calcification only exists in a local area. Calcifications close to lumen may be influenced more than those close to lipid pool. And calcifications in the middle area of fibrous cap are seemly influenced more than those in the shoulder area. PMID:24955401

  5. Comparison of the x-ray attenuation properties of breast calcifications, aluminium, hydroxyapatite and calcium oxalate

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Mackenzie, A.; Dance, D. R.; Young, K. C.

    2013-04-01

    Aluminium is often used as a substitute material for calcifications in phantom measurements in mammography. Additionally, calcium oxalate, hydroxyapatite and aluminium are used in simulation studies. This assumes that these materials have similar attenuation properties to calcification, and this assumption is examined in this work. Sliced mastectomy samples containing calcification were imaged at ×5 magnification using a digital specimen cabinet. Images of the individual calcifications were extracted, and the diameter and contrast of each calculated. The thicknesses of aluminium required to achieve the same contrast as each calcification when imaged under the same conditions were calculated using measurements of the contrast of aluminium foils. As hydroxyapatite and calcium oxalate are also used to simulate calcifications, the equivalent aluminium thicknesses of these materials were also calculated using tabulated attenuation coefficients. On average the equivalent aluminium thickness was 0.85 times the calcification diameter. For calcium oxalate and hydroxyapatite, the equivalent aluminium thicknesses were 1.01 and 2.19 times the thickness of these materials respectively. Aluminium and calcium oxalate are suitable substitute materials for calcifications. Hydroxyapatite is much more attenuating than the calcifications and aluminium. Using solid hydroxyapatite as a substitute for calcification of the same size would lead to excessive contrast in the mammographic image.

  6. Comparison of the x-ray attenuation properties of breast calcifications, aluminium, hydroxyapatite and calcium oxalate.

    PubMed

    Warren, L M; Mackenzie, A; Dance, D R; Young, K C

    2013-04-01

    Aluminium is often used as a substitute material for calcifications in phantom measurements in mammography. Additionally, calcium oxalate, hydroxyapatite and aluminium are used in simulation studies. This assumes that these materials have similar attenuation properties to calcification, and this assumption is examined in this work. Sliced mastectomy samples containing calcification were imaged at ×5 magnification using a digital specimen cabinet. Images of the individual calcifications were extracted, and the diameter and contrast of each calculated. The thicknesses of aluminium required to achieve the same contrast as each calcification when imaged under the same conditions were calculated using measurements of the contrast of aluminium foils. As hydroxyapatite and calcium oxalate are also used to simulate calcifications, the equivalent aluminium thicknesses of these materials were also calculated using tabulated attenuation coefficients. On average the equivalent aluminium thickness was 0.85 times the calcification diameter. For calcium oxalate and hydroxyapatite, the equivalent aluminium thicknesses were 1.01 and 2.19 times the thickness of these materials respectively. Aluminium and calcium oxalate are suitable substitute materials for calcifications. Hydroxyapatite is much more attenuating than the calcifications and aluminium. Using solid hydroxyapatite as a substitute for calcification of the same size would lead to excessive contrast in the mammographic image.

  7. Mammogram - calcifications

    MedlinePlus

    Microcalcifications or macrocalcifications; Breast cancer - calcifications; Mammography - calcifications ... or take in as medicine does not cause calcifications in the breast. Most calcifications are not a ...

  8. Influence of Land Development on Holocene Porites Coral Calcification at Nagura Bay, Ishigaki Island, Japan

    PubMed Central

    Sowa, Kohki; Watanabe, Tsuyoshi; Kan, Hironobu; Yamano, Hiroya

    2014-01-01

    To evaluate the relationships between coral calcification, thermal stress, and sedimentation and eutrophication linked to human impact (hereafter referred to as “land development”) by river discharge, we analyzed growth characteristics in the context of a paleoenvironment that was reconstructed from geochemical signals in modern and fossil (1.2 cal kyr BP and 3.5 cal kyr BP, respectively) massive Porites corals from Nagura Bay (“Nagura”) and from modern Porites corals from the estuary of the Todoroki River, Shiraho Reef (“Todoroki”). Both sites are on Ishigaki Island, Japan, and Nagura is located approximately 12 km west of Todoroki. At Nagura, the individual corals provide time windows of 13 (modern), 10 (1.2 cal kyr BP), and 38 yr in length (3.5 cal kyr BP). Here, we present the coral annual calcification for Nagura and Todoroki, and (bi) monthly resolved records of Sr/Ca (a proxy of sea surface temperature (SST)) and Ba/Ca (a proxy of sedimentation and nutrients related to land development) for Nagura. At Nagura, the winter SST was cooler by 2.8°C in the 1.2 cal kyr BP, and the annual and winter SSTs in the 3.5 cal kyr BP were cooler by 2.6°C and 4.6°C, respectively. The annual periodicity of Ba/Ca in modern coral is linked to river discharge and is associated with land development including sugar cane cultivation. Modern coral calcification also has declined with SST warming and increasing Ba/Ca peaks in winter. However, calcification of fossil corals does not appear to have been influenced by variations in Sr/Ca and Ba/Ca. Modern coral growth characteristics at Nagura and Todoroki indicate that coral growth is both spatially and temporally influenced by river discharge and land development. At Nagura, our findings suggest that land development induces negative thermal sensitivity for calcification in winter due to sugar cane harvest, which is a specifically modern phenomenon. PMID:24586393

  9. Influence of land development on Holocene Porites coral calcification at Nagura Bay, Ishigaki Island, Japan.

    PubMed

    Sowa, Kohki; Watanabe, Tsuyoshi; Kan, Hironobu; Yamano, Hiroya

    2014-01-01

    To evaluate the relationships between coral calcification, thermal stress, and sedimentation and eutrophication linked to human impact (hereafter referred to as "land development") by river discharge, we analyzed growth characteristics in the context of a paleoenvironment that was reconstructed from geochemical signals in modern and fossil (1.2 cal kyr BP and 3.5 cal kyr BP, respectively) massive Porites corals from Nagura Bay ("Nagura") and from modern Porites corals from the estuary of the Todoroki River, Shiraho Reef ("Todoroki"). Both sites are on Ishigaki Island, Japan, and Nagura is located approximately 12 km west of Todoroki. At Nagura, the individual corals provide time windows of 13 (modern), 10 (1.2 cal kyr BP), and 38 yr in length (3.5 cal kyr BP). Here, we present the coral annual calcification for Nagura and Todoroki, and (bi) monthly resolved records of Sr/Ca (a proxy of sea surface temperature (SST)) and Ba/Ca (a proxy of sedimentation and nutrients related to land development) for Nagura. At Nagura, the winter SST was cooler by 2.8°C in the 1.2 cal kyr BP, and the annual and winter SSTs in the 3.5 cal kyr BP were cooler by 2.6°C and 4.6°C, respectively. The annual periodicity of Ba/Ca in modern coral is linked to river discharge and is associated with land development including sugar cane cultivation. Modern coral calcification also has declined with SST warming and increasing Ba/Ca peaks in winter. However, calcification of fossil corals does not appear to have been influenced by variations in Sr/Ca and Ba/Ca. Modern coral growth characteristics at Nagura and Todoroki indicate that coral growth is both spatially and temporally influenced by river discharge and land development. At Nagura, our findings suggest that land development induces negative thermal sensitivity for calcification in winter due to sugar cane harvest, which is a specifically modern phenomenon.

  10. Influences of organic matter and calcification rate on trace elements in aragonitic estuarine bivalve shells

    USGS Publications Warehouse

    Takesue, R.K.; Bacon, C.R.; Thompson, J.K.

    2008-01-01

    ., Bruguier O., Ordinola E., Barrett N. T. and Fontugne M. (2006) Calcification rate influence on trace element concentrations in aragonitic bivalve shells: evidences and mechanisms. Geochim. Cosmochim. Acta 70, 4906-4920] which predicts that [M]/Ca ratios increase as calcification rates increase and Ca2+ channel specificity decreases. This result, in combination with the possibility that there were ontogenetic variations in growth rates among individuals younger than 2 years, underscores the need to develop an independent age model for C. amurensis shells. If growth-rate effects on lattice-bound [M]/Ca ratios can be constrained, it may yet be possible to develop high-resolution geochemical proxies for external solution chemistry in low-salinity regions of SFB.

  11. [Ectopic calcification].

    PubMed

    Fukumoto, Seiji

    2014-02-01

    Calcium deposition can be observed in many tissues in addition to bones and teeth which physiologically calcify. This unphysiological calcification can damage several organs. It has been shown that vascular calcification which is a risk factor for cardiovascular events develops through similar mechanisms to physiological calcification. Further studies to clarify detailed mechanisms of calcification are necessary to develop measures that inhibit unphysiological ectopic calcification without affecting physiological calcification in bones and teeth.

  12. The combined influence of hydrodynamic forcing and calcification on the spatial distribution of alkalinity in a coral reef system

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenlin; Falter, James; Lowe, Ryan; Ivey, Greg

    2012-04-01

    We investigated the influence of hydrodynamic forcing (waves, tides, alongshore currents and winds) and net calcification by coral reef organisms on the spatial distribution of total alkalinity (TA) in a fringing reef system through a combination of field measurements and numerical modeling. A field experiment was conducted over 10 days in Coral Bay (Ningaloo Reef, Western Australia) during which we measured wave heights, currents, and tides as well as the spatial distribution of TA across the fore reef, reef crest, and lagoon. We used observed changes in TA on the adjacent reef flat, along with synoptic measurements of cross-reef transport, to estimate in situ rates of net calcification (gcv) using a control volume approach. Based on the gcv estimated, we simulated light-driven, diurnal variations in benthic net calcification within a three-dimensional ocean circulation model, ROMS (Regional Ocean Modeling System). By coupling ROMS with a spectral wave model (Simulating Waves Nearshore), we were able to simulate currents within Coral Bay reef-lagoon system that were in good agreement with the field observations and demonstrate that circulation with the system was wave-dominated. Both the field measurements and numerical model output confirmed that both residence time (τR) and TA varied primarily with offshore wave heights and location within the bay. However, variations in TA were also affected by the nonlinear interaction between rates of net calcification that varied as a function of diurnally changing light and water residence time that varied as a function of offshore wave heights.

  13. Procyanidins-crosslinked aortic elastin scaffolds with distinctive anti-calcification and biological properties.

    PubMed

    Wang, Xiaoya; Zhai, Wanyin; Wu, Chengtie; Ma, Bing; Zhang, Jiamin; Zhang, Hongfeng; Zhu, Ziyan; Chang, Jiang

    2015-04-01

    Elastin, a main component of decellularized extracellular matrices and elastin-containing materials, has been used for tissue engineering applications due to their excellent biocompatibility. However, elastin is easily calcified, leading to the decrease of life span for elastin-based substitutes. How to inhibit the calcification of elastin-based scaffolds, but maintain their good biocompatibility, still remains significantly challenging. Procyanidins (PC) are a type of natural polyphenols with crosslinking ability. To investigate whether pure elastin could be crosslinked by PC with anti-calcification effect, PC was first used to crosslink aortic elastin. Results show that PC can crosslink elastin and effectively inhibit elastin-initiated calcification. Further experiments reveal the possible mechanisms for the anti-calcification of PC crosslinking including (1) inhibiting inflammation cell attachment, and secretion of inflammatory factors such as MMPs and TNF-α, (2) preventing elastin degradation by elastase, and (3) direct inhibition of mineral nucleation in elastin. Moreover, the PC-crosslinked aortic elastin maintains natural structure with high pore volume (1111 μL/g), large pore size (10-300 μm) and high porosity (75.1%) which facilitates recellularization of scaffolds in vivo, and displays excellent hemocompatibility, anti-thrombus and anti-inflammatory potential. The advantages of PC-crosslinked porous aortic elastin suggested that it can serve as a promising scaffold for tissue engineering.

  14. Influence of Eunice norvegica on feeding and calcification in the coral Lophelia pertusa

    NASA Astrophysics Data System (ADS)

    Mueller, C. E.; van Oevelen, D.; Middelburg, J. J.; Lundälv, T.

    2012-04-01

    Lophelia pertusa is the main framework building cold-water coral in the North Atlantic. It forms complex reef structures, extending up to several km in length and several meters in hight. Many species are attracted by the coral frame work, forming a highly diverse community within the reef. Although most work has focused on the corals, the functioning of the system also depends on interactions between corals and associated species. A particular example is the Polychaete Eunice norvegica that lives in close association with the coral host. The Polychaete builds a thin texture-tube between living coral branches and stimulates the coral to calcify the tube. This process strengthens the reef framwork by thickening and connecting coral brances and thereby acts as a positive feedback on the development of large reef structures. This comes however at an metabolic cost for the coral due to the enhanced calcificationrates. Another negative feedback for cold-water coral may be food related, since aquaria observations have shown that Eunice occasionally steels food from its host coral. In this study we investigated the interactions between the coral and polychaete related to calcification and food partitioning for two food types (algae and Artemia). The uptake of 13C and 15N labeled food sources by the worm and the coral was studied in chambers with only corals, only the polychaete and both species present. After 7 days, corals and worms were analyzed for isotope incorporation in bulk tissue and skeleton samples and specific fatty acids (13C) using GC-c-IRMS (gas-chromatography-combustion-isotope ratio mass spectrometry). Corals that were kept in the presence of Eunice indeed showed a higher calcification rates of 7.4 ug C (day* g dw coral)-1, evidencing the stimulation of calcification by Eunice. Interestingly, food uptake of algae and Artemia was higher in the coral-worm treatment for both species as compared to the single species treatments. These results shed new light on

  15. Influence of silk-silica fusion protein design on silica condensation in vitro and cellular calcification

    PubMed Central

    Plowright, Robyn; Dinjaski, Nina; Zhou, Shun; Belton, David J.; Kaplan, David L.; Perry, Carole C.

    2016-01-01

    Biomaterial design via genetic engineering can be utilized for the rational functionalization of proteins to promote biomaterial integration and tissue regeneration. Spider silk has been extensively studied for its biocompatibility, biodegradability and extraordinary material properties. As a protein-based biomaterial, recombinant DNA derived derivatives of spider silks have been modified with biomineralization domains which lead to silica deposition and potentially accelerated bone regeneration. However, the influence of the location of the R5 (SSKKSGSYSGSKGSKRRIL) silicifying domain fused with the spider silk protein sequence on the biosilicification process remains to be determined. Here we designed two silk-R5 fusion proteins that differed in the location of the R5 peptide, C- vs. N-terminus, where the spider silk domain consisted of a 15mer repeat of a 33 amino acid consensus sequence of the major ampullate dragline Spidroin 1 from Nephila clavipes (SGRGGLGGQG AGAAAAAGGA GQGGYGGLGSQGT). The chemical, physical and silica deposition properties of these recombinant proteins were assessed and compared to a silk 15mer control without the R5 present. The location of the R5 peptide did not have a significant effect on wettability and surface energies, while the C-terminal location of the R5 promoted more controlled silica precipitation, suggesting differences in protein folding and possibly different access to charged amino acids that drive the silicification process. Further, cell compatibility in vitro, as well as the ability to promote human bone marrow derived mesenchymal stem cell (hMSC) differentiation were demonstrated for both variants of the fusion proteins. PMID:26989487

  16. On the effect of calcification volume and configuration on the mechanical behaviour of carotid plaque tissue.

    PubMed

    Barrett, H E; Cunnane, E M; Kavanagh, E G; Walsh, M T

    2016-03-01

    Vascular calcification is a complex molecular process that exhibits a number of relatively characteristic morphology patterns in atherosclerotic plaques. Treatment of arterial stenosis by endovascular intervention, involving forceful circumferential expansion of the plaque, can be unpredictable in calcified lesions. The aim of this study was to determine the mechanical stretching mechanisms and define the mechanical limits for circumferentially expanding carotid plaque lesions under the influence of distinct calcification patterns. Mechanical and structural characterisation was performed on 17 human carotid plaques acquired from patients undergoing endarterectomy procedures. The mechanical properties were determined using uniaxial extension tests that stretch the lesions to complete failure along their circumferential axis. Calcification morphology of mechanically ruptured plaque lesions was characterised using high resolution micro computed tomography imaging. Scanning electron microscopy was used to examine the mechanically induced failure sites and to identify the interface boundary conditions between calcified and non-calcified tissue. The mechanical tests produced four distinct trends in mechanical behaviour which corresponded to the calcification patterns that structurally defined each mechanical group. Each calcification pattern produced unique mechanical restraining effects on the plaque tissue stretching properties evidenced by the variation in degree of stretch to failure. Resistance to failure appears to rely on interactions between calcification and non-calcified tissue. Scanning electron microscopy examination revealed structural gradations at interface boundary conditions to facilitate the transfer of stress. This study emphasises the mechanical influence of distinct calcification configurations on plaque expansion properties and highlights the importance of pre-operative lesion characterisation to optimise treatment outcomes.

  17. Calcification of the planktonic foraminifera Globigerina bulloides and carbonate ion concentration: Results from the Santa Barbara Basin

    NASA Astrophysics Data System (ADS)

    Osborne, Emily B.; Thunell, Robert C.; Marshall, Brittney J.; Holm, Jessica A.; Tappa, Eric J.; Benitez-Nelson, Claudia; Cai, Wei-Jun; Chen, Baoshan

    2016-08-01

    Planktonic foraminiferal calcification intensity, reflected by shell wall thickness, has been hypothesized to covary with the carbonate chemistry of seawater. Here we use both sediment trap and box core samples from the Santa Barbara Basin to evaluate the relationship between the calcification intensity of the planktonic foraminifera species Globigerina bulloides, measured by area density (µg/µm2), and the carbonate ion concentration of seawater ([CO32-]). We also evaluate the influence of both temperature and nutrient concentration ([PO43-]) on foraminiferal calcification and growth. The presence of two G. bulloides morphospecies with systematically different calcification properties and offset stable isotopic compositions was identified within sampling populations using distinguishing morphometric characteristics. The calcification temperature and by extension calcification depth of the more abundant "normal" G. bulloides morphospecies was determined using δ18O temperature estimates. Calcification depths vary seasonally with upwelling and were used to select the appropriate [CO32-], temperature, and [PO43-] depth measurements for comparison with area density. Seasonal upwelling in the study region also results in collinearity between independent variables complicating a straightforward statistical analysis. To address this issue, we use additional statistical diagnostics and a down core record to disentangle the respective roles of each parameter on G. bulloides calcification. Our results indicate that [CO32-] is the primary variable controlling calcification intensity while temperature influences shell size. We report a modern calibration for the normal G. bulloides morphospecies that can be used in down core studies of well-preserved sediments to estimate past [CO32-].

  18. Shellfish Face Uncertain Future in High CO2 World: Influence of Acidification on Oyster Larvae Calcification and Growth in Estuaries

    PubMed Central

    Miller, A. Whitman; Reynolds, Amanda C.; Sobrino, Cristina; Riedel, Gerhardt F.

    2009-01-01

    Background Human activities have increased atmospheric concentrations of carbon dioxide by 36% during the past 200 years. One third of all anthropogenic CO2 has been absorbed by the oceans, reducing pH by about 0.1 of a unit and significantly altering their carbonate chemistry. There is widespread concern that these changes are altering marine habitats severely, but little or no attention has been given to the biota of estuarine and coastal settings, ecosystems that are less pH buffered because of naturally reduced alkalinity. Methodology/Principal Findings To address CO2-induced changes to estuarine calcification, veliger larvae of two oyster species, the Eastern oyster (Crassostrea virginica), and the Suminoe oyster (Crassostrea ariakensis) were grown in estuarine water under four pCO2 regimes, 280, 380, 560 and 800 µatm, to simulate atmospheric conditions in the pre-industrial era, present, and projected future concentrations in 50 and 100 years respectively. CO2 manipulations were made using an automated negative feedback control system that allowed continuous and precise control over the pCO2 in experimental aquaria. Larval growth was measured using image analysis, and calcification was measured by chemical analysis of calcium in their shells. C. virginica experienced a 16% decrease in shell area and a 42% reduction in calcium content when pre-industrial and end of 21st century pCO2 treatments were compared. C. ariakensis showed no change to either growth or calcification. Both species demonstrated net calcification and growth, even when aragonite was undersaturated, a result that runs counter to previous expectations for invertebrate larvae that produce aragonite shells. Conclusions and Significance Our results suggest that temperate estuarine and coastal ecosystems are vulnerable to the expected changes in water chemistry due to elevated atmospheric CO2 and that biological responses to acidification, especially calcifying biota, will be species-specific and

  19. Visceral adipose tissue influences on coronary artery calcification at young and middle-age groups using computed tomography angiography

    PubMed Central

    Abazid, Rami M.; Kattea, M. Obadah; Sayed, Sawsan; Saqqah, Hanaa; Qintar, Mohammed; Smettei, Osama A.

    2015-01-01

    Purpose: The purpose of the study was to evaluate the impact of excessive visceral adipose tissue (VAT) on subclinical coronary atherosclerosis and coronary artery calcifications (CAC) in young and middle-age groups using multislice computed tomography. Methods: This study is a single center, cross-sectional study. Eligible patients (n = 159), who under the age of 61 years, with chest pain and mild to moderate probability to have coronary artery disease (CAD) were enrolled. Coronary calcium score and epicardial adipose tissue (EAT) were measured at the level of the left main coronary artery while VAT was measured at the level of the iliac crest. Results: The average age was (48 ± 8 years). The mean VAT was (38 ± 21 cm2) with no significant difference between men and women (38 ± 22 vs. 37 ± 19 P = 0.8) respectively. Student's t-test analysis showed significantly higher VAT in patients with detectable CAC than patients with no CAC (48 ± 24 vs. 33 ± 18 P = 0.00002), respectively. Univariate regression analysis showed that VAT and EAT, are strong predictor for CAC (hazard ratio [HR] 1.034, 95% confidence interval [CI: 1.016–1.052]. P <0.001 and [HR] 1.344, 95% CI: [1.129–1.601] P = 0.001), respectively. Conclusion: Excessive VAT is significantly associated with positive CAC. VAT can strongly predict subclinical CAD in individuals at young and middle-age groups. PMID:26229760

  20. Middle Cerebral Artery Calcification

    PubMed Central

    Kao, Hung-Wen; Liou, Michelle; Chung, Hsiao-Wen; Liu, Hua-Shan; Tsai, Ping-Huei; Chiang, Shih-Wei; Chou, Ming-Chung; Peng, Giia-Sheun; Huang, Guo-Shu; Hsu, Hsian-He; Chen, Cheng-Yu

    2015-01-01

    Abstract Calcification of the middle cerebral artery (MCA) is uncommon in the healthy elderly. Whether calcification of the MCA is associated with cerebral ischemic stroke remains undetermined. We intended to investigate the association using Agatston calcium scoring of the MCA. This study retrospectively included 354 subjects with ischemic stroke in the MCA territory and 1518 control subjects who underwent computed tomography (CT) of the brain. We recorded major known risk factors for ischemic stroke, including age, gender, hypertension, diabetes mellitus, smoking, hyperlipidemia, and obesity, along with the MCA calcium burden, measured with the Agatston calcium scoring method. Univariate and modified logistic regression analyses were performed to examine the association between the MCA calcification and ischemic stroke. The univariate analyses showed significant associations of ischemic stroke with age, hypertension, diabetes mellitus, smoking, total MCA Agatston score, and the presence of calcification on both or either side of the MCA. Subjects with the presence of MCA calcification on both or either side of the MCA were 8.46 times (95% confidence interval, 4.93–14.53; P < 0.001) more likely to have a cerebral infarct than subjects without MCA calcification after adjustment for the major known risk factors, including age, hypertension, diabetes mellitus, and smoking. However, a higher degree of MCA calcification reflected by the Agatston score was not associated with higher risk of MCA ischemic stroke after adjustment for the confounding factors and presence of MCA calcification. These results suggest that MCA calcification is associated with ischemic stroke in the MCA territory. Further prospective studies are required to verify the clinical implications of the MCA calcification. PMID:26683969

  1. [Diabetes mellitus and vascular calcification].

    PubMed

    Okuno, Yasuhisa; Sato, Kyoko

    2002-08-01

    Two types of arterial calcification are well recognized:intimal (atherosclerotic) and medial (Monckeberg type). These two calcifications are considered different in pathogenesis. Arterial calcification has recently been reported to be an organized, regulated process similar to bone formation. The relation of calcification to diabetes mellitus remains still unclear. EBCT can noninvasively and accurately detect coronary artery calcification. Diabetic patients seem to have increased prevalence of coronary calcification when compared with non-diabetic patients. Medial artery calcification is an independent predictor of cardiovascular mortality in diabetic patients. PMID:15775402

  2. Calcific Metamorphosis: A Review

    PubMed Central

    Siddiqui, Shoaib Haider; Mohamed, Ahmed Nabil

    2016-01-01

    Dental trauma to the permanent dentition can lead to clinical complications and its management may considerably challenge a practitioner. The incidence of pulp canal obliteration following dental trauma has been reported to be approximately 4 – 24%. Attempting to locate canals following calcific metamorphosis and negotiating it to full working length may lead to iatrogenic errors such as fractured instrument and perforation. This review article describes the possible etiology of Calcific Metamorphosis, its clinical and radiographic features as well as its management.

  3. Calcific Metamorphosis: A Review.

    PubMed

    Siddiqui, Shoaib Haider; Mohamed, Ahmed Nabil

    2016-07-01

    Dental trauma to the permanent dentition can lead to clinical complications and its management may considerably challenge a practitioner. The incidence of pulp canal obliteration following dental trauma has been reported to be approximately 4 - 24%. Attempting to locate canals following calcific metamorphosis and negotiating it to full working length may lead to iatrogenic errors such as fractured instrument and perforation. This review article describes the possible etiology of Calcific Metamorphosis, its clinical and radiographic features as well as its management. PMID:27610067

  4. Myocardial fibre calcification.

    PubMed Central

    McClure, J; Pieterse, A S; Pounder, D J; Smith, P S

    1981-01-01

    Three cases of myocardial fibre calcification found at post-mortem examination are described. In one case there was antemortem hypercalcaemia and hyperphosphataemia and the case was clearly an example of metastatic calcification. In the other two cases there was ischaemic myocardial necrosis and calcification was seen in fibres which were not overtly necrotic, but which were both in proximity to (the majority) and remote from the necrotic zones. Since renal failure with hyperphosphataemia was present in both cases, these were considered to be examples of augmented (by the hyperphosphataemia) dystrophic calcification. The histological, histochemical and ultrastructural features were identical in the three cases. Hydroxyapatite formation was observed initially in mitochondria, followed by spillage of crystals into the cytosol and ultimately into the interstitium. It is suggested that the fundamental lesion is a dysfunction of the fibre membrane; the similarity of this reaction with the calcification seen in skeletal muscle fibres in various myopathies is noted and a unifying hypothesis of the mechanism of skeletal and cardiac muscle fibre calcification is thereby suggested. Images PMID:7309897

  5. Coral calcification and ocean acidification

    USGS Publications Warehouse

    Jokiel, Paul L.; Jury, Christopher P.; Kuffner, Ilsa B.

    2016-01-01

    calcification and increases in Gnet. These relationships result in a correlation between Gnet and Ωarag, with both parameters being variables dependent on Pnet. Consequently the correlation between Gnet and Ωarag varies widely between different locations and times depending on the relative metabolic contributions of various calcifying and photosynthesizing organisms and local rates of carbonate dissolution. High rates of H+ efflux continue for several hours following the mid-day Gnet peak suggesting that corals have difficulty in shedding waste protons as described by the Proton Flux Model. DIC flux (uptake) tracks Pnet and Gnet and drops off rapidly after the photosynthesis-calcification maxima, indicating that corals can cope more effectively with the problem of limited DIC supply compared to the problem of eliminating H+. Predictive models of future global changes in coral and coral reef growth based on oceanic Ωarag must include the influence of future changes in localized Pnet on Gnet as well as changes in rates of reef carbonate dissolution. The correlation between Ωarag and Gnet over the diel cycle is simply the result of increasing pH due to photosynthesis that shifts the CO2-carbonate system equilibria to increase [CO32] relative to the other DIC components of [HCO3] and [CO2]. Therefore Ωarag closely tracks pH as an effect of Pnet, which also drives changes in Gnet. Measurements of DIC flux and H+ flux are far more useful than concentrations in describing coral metabolism dynamics. Coral reefs are systems that exist in constant disequilibrium with the water column.

  6. Calcific uremic arteriolopathy

    PubMed Central

    Sowers, Kurt M

    2010-01-01

    Calcific uremic arteriolopathy (CUA)/calciphylaxis is an important cause of morbidity and mortality in patients with chronic kidney disease requiring renal replacement. Once thought to be rare, it is being increasingly recognized and reported on a global scale. The uremic milieu predisposes to multiple metabolic toxicities including increased levels of reactive oxygen species and inflammation. Increased oxidative stress and inflammation promote this arteriolopathy by adversely affecting endothelial function resulting in a prothrombotic milieu and significant remodeling effects on vascular smooth muscle cells. These arteriolar pathological effects include intimal hyperplasia, inflammation, endovascular fibrosis and vascular smooth muscle cell apoptosis and differentiation into bone forming osteoblast-like cells resulting in medial calcification. Systemic factors promoting this vascular condition include elevated calcium, parathyroid hormone and hyperphosphatemia with consequent increases in the calcium × phosphate product. The uremic milieu contributes to a marked increased in upstream reactive oxygen species—oxidative stress and subsequent downstream increased inflammation, in part, via activation of the nuclear transcription factor NFκB and associated downstream cytokine pathways. Consitutive anti-calcification proteins such as Fetuin-A and matrix GLA proteins and their signaling pathways may be decreased, which further contributes to medial vascular calcification. The resulting clinical entity is painful, debilitating and contributes to the excess morbidity and mortality associated with chronic kidney disease and end stage renal disease. These same histopathologic conditions also occur in patients without uremia and therefore, the term calcific obliterative arteriolopathy could be utilized in these conditions. PMID:20716935

  7. Calcific Metamorphosis: A Review

    PubMed Central

    Siddiqui, Shoaib Haider; Mohamed, Ahmed Nabil

    2016-01-01

    Dental trauma to the permanent dentition can lead to clinical complications and its management may considerably challenge a practitioner. The incidence of pulp canal obliteration following dental trauma has been reported to be approximately 4 – 24%. Attempting to locate canals following calcific metamorphosis and negotiating it to full working length may lead to iatrogenic errors such as fractured instrument and perforation. This review article describes the possible etiology of Calcific Metamorphosis, its clinical and radiographic features as well as its management. PMID:27610067

  8. Familial idiopathic cerebral calcifications.

    PubMed Central

    Boller, F; Boller, M; Gilbert, J

    1977-01-01

    Nine members of a family spanning three generations showed bilateral calcifications of the basal ganglia with autosomal dominant inheritance. Two members developed chorea, dementia, and a characteristic speech disturbance (palialalia) in the third or fourth decade. A third member possibly shows the initial stage of a similar syndrome. Six members with calcifications but without neurological signs are younger than 25 years. All nine patients had normal calcium and phosphorus, and no evidence of endocrinological or somatic abnormalities. Thie 'isiopathic' picture must be differentiated from hypoparathyroidism and pseudohypoparathyroidism. Images PMID:886353

  9. Associations between Thyroid Hormones, Calcification Inhibitor Levels and Vascular Calcification in End-Stage Renal Disease

    PubMed Central

    Meuwese, Christiaan Lucas; Olauson, Hannes; Qureshi, Abdul Rashid; Ripsweden, Jonaz; Barany, Peter; Vermeer, Cees; Drummen, Nadja; Stenvinkel, Peter

    2015-01-01

    Introduction Vascular calcification is a common, serious and elusive complication of end-stage renal disease (ESRD). As a pro-calcifying risk factor, non-thyroidal illness may promote vascular calcification through a systemic lowering of vascular calcification inhibitors such as matrix-gla protein (MGP) and Klotho. Methods and Material In 97 ESRD patients eligible for living donor kidney transplantation, blood levels of thyroid hormones (fT3, fT4 and TSH), total uncarboxylated MGP (t-ucMGP), desphospho-uncarboxylated MGP (dp-ucMGP), descarboxyprothrombin (PIVKA-II), and soluble Klotho (sKlotho) were measured. The degree of coronary calcification and arterial stiffness were assessed by means of cardiac CT-scans and applanation tonometry, respectively. Results fT3 levels were inversely associated with coronary artery calcification (CAC) scores and measures of arterial stiffness, and positively with dp-ucMGP and sKlotho concentrations. Subfractions of MGP, PIVKA-II and sKlotho did not associate with CAC scores and arterial stiffness. fT4 and TSH levels were both inversely associated with CAC scores, but not with arterial stiffness. Discussion The positive associations between fT3 and dp-ucMGP and sKlotho suggest that synthesis of MGP and Klotho is influenced by thyroid hormones, and supports a link between non-thyroidal illness and alterations in calcification inhibitor levels. However, the absence of an association between serum calcification inhibitor levels and coronary calcification/arterial stiffness and the fact that MGP and Klotho undergo post-translational modifications underscore the complexity of this association. Further studies, measuring total levels of MGP and membrane bound Klotho, should examine this proposed pathway in further detail. PMID:26147960

  10. TWEAK favors phosphate-induced calcification of vascular smooth muscle cells through canonical and non-canonical activation of NFκB

    PubMed Central

    Hénaut, L; Sanz, A B; Martin-Sanchez, D; Carrasco, S; Villa-Bellosta, R; Aldamiz-Echevarria, G; Massy, Z A; Sanchez-Nino, M D; Ortiz, A

    2016-01-01

    Vascular calcification (VC) is associated with increased cardiovascular mortality in aging, chronic kidney disease (CKD), type 2 diabetes mellitus (T2DM) and atherosclerosis. TNF-like weak inducer of apoptosis (TWEAK) recently emerged as a new biomarker for the diagnosis and prognosis of cardiovascular diseases. TWEAK binding to its functional receptor Fn14 was reported to promote several steps of atherosclerotic plaque progression. However, no information is currently available on the role of TWEAK/Fn14 on the development of medial calcification, which is highly prevalent in aging, CKD and T2DM. This study explored the involvement of TWEAK in human vascular smooth muscle cells (h-VSMCs) calcification in vitro. We report that TWEAK binding to Fn14 promotes inorganic phosphate-induced h-VSMCs calcification, favors h-VSMCs osteogenic transition, decreasing acta2 and myh11 and increasing bmp2 mRNA and tissue non-specific alkaline phosphatase (TNAP), and increases MMP9 activity. Blockade of the canonical NFκB pathway reduced by 80% TWEAK pro-calcific properties and decreased osteogenic transition, TNAP and MMP9 activity. Blockade of non-canonical NFκB signaling by a siRNA targeting RelB reduced by 20% TWEAK pro-calcific effects and decreased TWEAK-induced loss of h-VSMCs contractile phenotype and MMP9 activity, without modulating bmp2 mRNA or TNAP activity. Inhibition of ERK1/2 activation by a MAPK kinase inhibitor did not influence TWEAK pro-calcific properties. Our results suggest that TWEAK/Fn14 directly favors inorganic phosphate-induced h-VSMCs calcification by activation of both canonical and non-canonical NFκB pathways. Given the availability of neutralizing anti-TWEAK strategies, our study sheds light on the TWEAK/Fn14 axis as a novel therapeutic target in the prevention of VC. PMID:27441657

  11. Pineal Calcification Among Black Patients

    PubMed Central

    Fan, Kuang-Jaw

    1983-01-01

    A postmortem histopathological study was done in 233 pineal glands of black patients. Among them, 70 percent showed microscopic evidence of calcification in the pineal parenchyma. The frequency of calcification increased with age. However, the severity of calcification reached the peak in the 60 to 69 year old age group and then gradually declined. As compared to males, females had slightly higher frequency and reached the peak of severity in younger age groups. When pineal calcification was compared among patients with various malignancies, a higher frequency and more severe calcification were observed in patients with carcinoma of the prostate and the pancreas. A lower frequency and less severe calcification were observed in patients with carcinoma of the breast and the cervix. The results of this study emphasize the important role of sex hormone in genesis of pineal calcification. PMID:6631985

  12. Pineal calcification among black patients.

    PubMed

    Fan, K J

    1983-08-01

    A postmortem histopathological study was done in 233 pineal glands of black patients. Among them, 70 percent showed microscopic evidence of calcification in the pineal parenchyma. The frequency of calcification increased with age. However, the severity of calcification reached the peak in the 60 to 69 year old age group and then gradually declined. As compared to males, females had slightly higher frequency and reached the peak of severity in younger age groups. When pineal calcification was compared among patients with various malignancies, a higher frequency and more severe calcification were observed in patients with carcinoma of the prostate and the pancreas. A lower frequency and less severe calcification were observed in patients with carcinoma of the breast and the cervix. The results of this study emphasize the important role of sex hormone in genesis of pineal calcification.

  13. Arterial calcification: Conscripted by collagen

    NASA Astrophysics Data System (ADS)

    Miller, Jordan D.

    2016-03-01

    In atherosclerotic plaques, patterns of calcification -- which have profound implications for plaque stability and vulnerability to rupture -- are determined by the collagen's content and patterning throughout the plaque.

  14. Preliminary Study on Composition and Microstructure of Calcification in Craniopharyngiomas

    PubMed Central

    Peng, Junxiang; Qi, Songtao; Pan, Jun; Zhang, Xi’an; Huang, Guanglong; Li, Danling

    2016-01-01

    Abstract To analyze the element composition and microstructure of calcification in craniopharyngiomas and to explore the differences among differing degrees of calcification, 50 consecutive patients with craniopharyngioma were selected. X-ray diffraction analysis and energy-dispersive X-ray spectroscopy analysis were performed on the calcified plaques isolated from the tumor specimens. All calcified plaques were constituted of hydroxyapatite crystals and some amorphous materials. The main elements for the analysis were calcium, phosphate, carbon, and oxygen. There were significant differences among groups of differing degrees of calcification in the percentage composition of calcium, phosphorus, and carbon (P < 0.05), in which the element content of calcium and phosphorus had a positive correlation with the extent of calcification (rp = 0.745 and 0.778, respectively, P < 0.01), while the element content of carbon had a negative correlation with the extent of calcification (rp =−0.526, P <0.01). The calcium, phosphorus, and carbon content are different in calcified plaques with different extents of calcification. The element content of calcium, phosphorus, and carbon influences the degree of calcification. PMID:27213742

  15. Vascular calcification: Mechanisms of vascular smooth muscle cell calcification.

    PubMed

    Leopold, Jane A

    2015-05-01

    Vascular calcification is highly prevalent and, when present, is associated with major adverse cardiovascular events. Vascular smooth muscle cells play an integral role in mediating vessel calcification by undergoing differentiation to osteoblast-like cells and generating matrix vesicles that serve as a nidus for calcium-phosphate deposition in the vessel wall. Once believed to be a passive process, it is now recognized that vascular calcification is a complex and highly regulated process that involves activation of cellular signaling pathways, circulating inhibitors of calcification, genetic factors, and hormones. This review will examine several of the key mechanisms linking vascular smooth muscle cells to vessel calcification that may be targeted to reduce vessel wall mineralization and, thereby, reduce cardiovascular risk.

  16. Hemodynamic and cellular response feedback in calcific aortic valve disease.

    PubMed

    Gould, Sarah T; Srigunapalan, Suthan; Simmons, Craig A; Anseth, Kristi S

    2013-07-01

    This review highlights aspects of calcific aortic valve disease that encompass the entire range of aortic valve disease progression from initial cellular changes to aortic valve sclerosis and stenosis, which can be initiated by changes in blood flow (hemodynamics) and pressure across the aortic valve. Appropriate hemodynamics is important for normal valve function and maintenance, but pathological blood velocities and pressure can have profound consequences at the macroscopic to microscopic scales. At the macroscopic scale, hemodynamic forces impart shear stresses on the surface of the valve leaflets and cause deformation of the leaflet tissue. As discussed in this review, these macroscale forces are transduced to the microscale, where they influence the functions of the valvular endothelial cells that line the leaflet surface and the valvular interstitial cells that populate the valve extracellular matrix. For example, pathological changes in blood flow-induced shear stress can cause dysfunction, impairing their homeostatic functions, and pathological stretching of valve tissue caused by elevated transvalvular pressure can activate valvular interstitial cells and latent paracrine signaling cytokines (eg, transforming growth factor-β1) to promote maladaptive tissue remodeling. Collectively, these coordinated and complex interactions adversely impact bulk valve tissue properties, feeding back to further deteriorate valve function and propagate valve cell pathological responses. Here, we review the role of hemodynamic forces in calcific aortic valve disease initiation and progression, with focus on cellular responses and how they feed back to exacerbate aortic valve dysfunction.

  17. Impact of calcifications on patient-specific wall stress analysis of abdominal aortic aneurysms.

    PubMed

    Maier, A; Gee, M W; Reeps, C; Eckstein, H-H; Wall, W A

    2010-10-01

    As a degenerative and inflammatory desease of elderly patients, about 80% of abdominal aortic aneurysms (AAA) show considerable wall calcification. Effect of calcifications on computational wall stress analyses of AAAs has been rarely treated in literature so far. Calcifications are heterogeneously distributed, non-fibrous, stiff plaques which are most commonly found near the luminal surface in between the intima and the media layer of the vessel wall. In this study, we therefore investigate the influence of calcifications as separate AAA constituents on finite element simulation results. Thus, three AAAs are reconstructed with regard to intraluminal thrombus (ILT), calcifications and vessel wall. Each patient-specific AAA is simulated twice, once including all three AAA constituents and once neglecting calcifications as it is still common in literature. Parameters for constitutive modeling of calcifications are thereby taken from experiments performed by the authors, showing that calcifications exhibit an almost linear stress-strain behavior with a Young's modulus E ≥ 40 MPa. Simulation results show that calcifications exhibit significant load-bearing effects and reduce stress in adjacent vessel wall. Average stress within the vessel wall is reduced by 9.7 to 59.2%. For two out of three AAAs, peak wall stress decreases when taking calcifications into consideration (8.9 and 28.9%). For one AAA, simulated peak wall stress increases by 5.5% due to stress peaks near calcification borders. However, such stress singularities due to sudden stiffness jumps are physiologically doubtful. It can further be observed that large calcifications are mostly situated in concavely shaped regions of the AAA wall. We deduce that AAA shape is influenced by existent calcifications, thus crucial errors occur if they are neglected in computational wall stress analyses. A general increase in rupture risk for calcified AAAs is doubted.

  18. Impact of calcifications on patient-specific wall stress analysis of abdominal aortic aneurysms.

    PubMed

    Maier, A; Gee, M W; Reeps, C; Eckstein, H-H; Wall, W A

    2010-10-01

    As a degenerative and inflammatory desease of elderly patients, about 80% of abdominal aortic aneurysms (AAA) show considerable wall calcification. Effect of calcifications on computational wall stress analyses of AAAs has been rarely treated in literature so far. Calcifications are heterogeneously distributed, non-fibrous, stiff plaques which are most commonly found near the luminal surface in between the intima and the media layer of the vessel wall. In this study, we therefore investigate the influence of calcifications as separate AAA constituents on finite element simulation results. Thus, three AAAs are reconstructed with regard to intraluminal thrombus (ILT), calcifications and vessel wall. Each patient-specific AAA is simulated twice, once including all three AAA constituents and once neglecting calcifications as it is still common in literature. Parameters for constitutive modeling of calcifications are thereby taken from experiments performed by the authors, showing that calcifications exhibit an almost linear stress-strain behavior with a Young's modulus E ≥ 40 MPa. Simulation results show that calcifications exhibit significant load-bearing effects and reduce stress in adjacent vessel wall. Average stress within the vessel wall is reduced by 9.7 to 59.2%. For two out of three AAAs, peak wall stress decreases when taking calcifications into consideration (8.9 and 28.9%). For one AAA, simulated peak wall stress increases by 5.5% due to stress peaks near calcification borders. However, such stress singularities due to sudden stiffness jumps are physiologically doubtful. It can further be observed that large calcifications are mostly situated in concavely shaped regions of the AAA wall. We deduce that AAA shape is influenced by existent calcifications, thus crucial errors occur if they are neglected in computational wall stress analyses. A general increase in rupture risk for calcified AAAs is doubted. PMID:20143120

  19. Thyroid calcifications: a pictorial essay.

    PubMed

    Lacout, Alexis; Chevenet, Carole; Thariat, Juliette; Marcy, Pierre Yves

    2016-05-01

    Incidental diagnosis of thyroid nodules is very common on adult neck ultrasonography examination. Thyroid calcifications are encountered in benign thyroid nodules and goiters as well as in thyroid malignancy. Depiction and characterization of such calcifications within a thyroid nodule may be a key element in the thyroid nodule diagnosis algorithm. The goal of this paper is to display typical radio-pathological correlations of various thyroid pathologies of benign and malignant conditions in which the calcification type diagnosis can play a key role in the final diagnosis of the thyroid nodule. PMID:26891122

  20. Decrease in coccolithophore calcification and CO2 since the middle Miocene

    NASA Astrophysics Data System (ADS)

    Bolton, Clara T.; Hernández-Sánchez, María T.; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M.

    2016-01-01

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone εp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity.

  1. Decrease in coccolithophore calcification and CO2 since the middle Miocene.

    PubMed

    Bolton, Clara T; Hernández-Sánchez, María T; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M

    2016-01-01

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone ɛp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity. PMID:26762469

  2. Decrease in coccolithophore calcification and CO2 since the middle Miocene.

    PubMed

    Bolton, Clara T; Hernández-Sánchez, María T; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M

    2016-01-14

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone ɛp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity.

  3. Decrease in coccolithophore calcification and CO2 since the middle Miocene

    PubMed Central

    Bolton, Clara T.; Hernández-Sánchez, María T.; Fuertes, Miguel-Ángel; González-Lemos, Saúl; Abrevaya, Lorena; Mendez-Vicente, Ana; Flores, José-Abel; Probert, Ian; Giosan, Liviu; Johnson, Joel; Stoll, Heather M.

    2016-01-01

    Marine algae are instrumental in carbon cycling and atmospheric carbon dioxide (CO2) regulation. One group, coccolithophores, uses carbon to photosynthesize and to calcify, covering their cells with chalk platelets (coccoliths). How ocean acidification influences coccolithophore calcification is strongly debated, and the effects of carbonate chemistry changes in the geological past are poorly understood. This paper relates degree of coccolith calcification to cellular calcification, and presents the first records of size-normalized coccolith thickness spanning the last 14 Myr from tropical oceans. Degree of calcification was highest in the low-pH, high-CO2 Miocene ocean, but decreased significantly between 6 and 4 Myr ago. Based on this and concurrent trends in a new alkenone ɛp record, we propose that decreasing CO2 partly drove the observed trend via reduced cellular bicarbonate allocation to calcification. This trend reversed in the late Pleistocene despite low CO2, suggesting an additional regulator of calcification such as alkalinity. PMID:26762469

  4. Calcification prevention tablets

    NASA Technical Reports Server (NTRS)

    Lindsay, Geoffrey A.; Hasting, Michael A.; Gustavson, Michael A.

    1991-01-01

    Citric acid tablets, which slowly release citric acid when flushed with water, are under development by the Navy for calcification prevention. The citric acid dissolves calcium carbonate deposits and chelates the calcium. For use in urinals, a dispenser is not required because the tablets are non-toxic and safe to handle. The tablets are placed in the bottom of the urinal, and are consumed in several hundred flushes (the release rate can be tailored by adjusting the formulation). All of the ingredients are environmentally biodegradable. Mass production of the tablets on commercial tableting machines was demonstrated. The tablets are inexpensive (about 75 cents apiece). Incidences of clogged pipes and urinals were greatly decreased in long term shipboard tests. The corrosion rate of sewage collection pipe (90/10 Cu/Ni) in citric acid solution in the laboratory is several mils per year at conditions typically found in traps under the urinals. The only shipboard corrosion seen to date is of the yellow brass urinal tail pieces. While this is acceptable, the search for a nontoxic corrosion inhibitor is underway. The shelf life of the tablets is at least one year if stored at 50 percent relative humidity, and longer if stored in sealed plastic buckets.

  5. Calcification Transformation of Diasporic Bauxite

    NASA Astrophysics Data System (ADS)

    Zhao, Qiuyue; Zhu, Xiaofeng; Lv, Guozhi; Zhang, Zimu; Yin, Zhengnan; Zhang, Tingan

    2016-06-01

    The disposal of red mud, which is a solid waste that is generated during the extraction of alumina from bauxite, is one of major problems faced by the aluminum industry. Alkali in red mud seeping under the soil may pollute land and water. The Northeastern University, China, has proposed a calcification-carbonation method to deal with low-grade bauxite or red mud. Its main purpose is to change the equilibrium phase of red mud to 2CaO·SiO2 and CaCO3 hydrometallurgically, so that recomposed alkali-free red mud can be widely used. We conducted calcification transformation experiments using diasporic bauxite sampled from Wenshan, and investigated the effects of parameters such as diasporic bauxite grain size, temperature and treatment time on the calcification transformation digestion rate, which is also termed the calcification transformation rate (CTR). The main phase in the calcification transformation slag (CTS) is hydrogarnet with different grain sizes. The CTR increases with decrease in diasporic bauxite grain size, or increase in temperature or reaction time. The CTR reaches a maximum of 87% after 120 min reaction at 240°C. The Na2O/Al2O3 ratio decreases with increase in temperature and reaches 1.5. The sodium content in the CTS decreases with increasing reaction time and is lower than that in the red mud treated using the Bayer process (4-12%).

  6. Experimental Calcification of the Myocardium

    PubMed Central

    Bonucci, Ermanno; Sadun, Raffaele

    1973-01-01

    Focal areas of calcification are frequent in rat myocardium 30 and 60 days after administration of dihydrotachysterol. These areas are PAS-positive, stain deeply with alcian blue and show high affinity for colloidal iron. Calcification is almost completely confined to intracellular structures. Small clusters of needle-shaped crystals are first found in apparently undamaged mitochondria in undamaged myocardial cells. When all the mitochondria are calcified, the cell degenerates, and inorganic crystals are laid down in relationship with its myofilaments. In other myocardial cells, clusters of amorphous or finely granular inorganic substance are found in both mitochondria and myofibrils. Both structures show signs of advanced degeneration. Inorganic substance has only occasionally been found within the structures of the sarcoplasmic reticulum. These structures do not seem to be involved in myocardial calcification under the present experimental conditions. Calcification of myocardial cells gives rise to a cellular reaction. Many macrophagic cells surround the calcified areas, which are rapidly reabsorbed. The present results show that myocardial mitochondria are actively engaged in controlling the intracellular concentration and movement of calcium ions. Their role in the myocardial contraction-relaxation cycle and the possible mechanism of myocardial calcification are discussed. ImagesFig 14Fig 1Fig 2Fig 3Fig 4Fig 5Fig 6Fig 7Fig 8Fig 9Fig 10Fig 11Fig 12Fig 13 PMID:4197422

  7. The effect of calcification on the structural mechanics of the costal cartilage.

    PubMed

    Forman, Jason L; Kent, Richard W

    2014-01-01

    The costal cartilage often undergoes progressive calcification with age. This study sought to investigate the effects of calcification on the structural mechanics of whole costal cartilage segments. Models were developed for five costal cartilage specimens, including representations of the cartilage, the perichondrium, calcification, and segments of the rib and sternum. The material properties of the cartilage were determined through indentation testing; the properties of the perichondrium were determined through optimisation against structural experiments. The calcified regions were then expanded or shrunk to develop five different sensitivity analysis models for each. Increasing the relative volume of calcification from 0% to 24% of the cartilage volume increased the stiffness of the costal cartilage segments by a factor of 2.3-3.8. These results suggest that calcification may have a substantial effect on the stiffness of the costal cartilage which should be considered when modelling the chest, especially if age is a factor.

  8. Effect of calcium carbonate saturation of seawater on coral calcification

    USGS Publications Warehouse

    Gattuso, J.-P.; Frankignoulle, M.; Bourge, I.; Romaine, S.; Buddemeier, R.W.

    1998-01-01

    The carbonate chemistry of seawater is usually not considered to be an important factor influencing calcium-carbonate-precipitation by corals because surface seawater is supersaturated with respect to aragonite. Recent reports, however, suggest that it could play a major role in the evolution and biogeography of recent corals. We investigated the calcification rates of five colonies of the zooxanthellate coral Stylophora pistillata in synthetic seawater using the alkalinity anomaly technique. Changes in aragonite saturation from 98% to 585% were obtained by manipulating the calcium concentration. The results show a nonlinear increase in calcification rate as a function of aragonite saturation level. Calcification increases nearly 3-fold when aragonite saturation increases from 98% to 390%, i.e., close to the typical present saturation state of tropical seawater. There is no further increase of calcification at saturation values above this threshold. Preliminary data suggest that another coral species, Acropora sp., displays a similar behaviour. These experimental results suggest: (l) that the rate of calcification does not change significantly within the range of saturation levels corresponding to the last glacial-interglacial cycle, and (2) that it may decrease significantly in the future as a result of the decrease in the saturation level due to anthropogenic release of CO2 into the atmosphere. Experimental studies that control environmental conditions and seawater composition provide unique opportunities to unravel the response of corals to global environmental changes.

  9. CT of schistosomal calcification of the intestine

    SciTech Connect

    Fataar, S.; Bassiony, H.; Satyanath, S.; Rudwan, M.; Hebbar, G.; Khalifa, A.; Cherian, M.J.

    1985-01-01

    The spectrum of schistosomal colonic calcification on abdominal radiographs has been described. The appearance on computed tomography (CT) is equally distinctive and occurs with varying degrees of genitourinary calcification. The authors have experience in three cases with the appearance on CT of intestinal calcification due to schistosomiasis.

  10. [Mechanism, imaging technique and therapy for vascular calcification in patients of chronic kidney disease].

    PubMed

    Yoshida, Hiraku; Yokoyama, Keitaro

    2007-05-01

    Vascular calcification has been reported to influence mortality and complications of cardiovascular diseases in patients with chronic kidney disease. Once vascular calcification was thought to the result from passive precipitation of calcium and phosphate, it now appears that end result of phenotypic change of vascular smooth muscle cells (VSMC) into osteoblast-like cells. A variety of imaging technique are available to visualize vascular calcification, including X-ray, vascular ultrasound, electron beam computed tomography (EBCT) and multidetector-row computed tomography (MDCT) . Especially, MDCT with contrast medium that can detect not only coronary calcification but also stenosis is useful and noninvasive methods for screening of coronary artery disease. Through greater understanding of both the mechanism and clinical consequence of vascular calcification, future therapeutic strategies may be more effectively designed and applied. PMID:17471002

  11. Arterial calcification: friend or foe?

    PubMed

    Nicoll, Rachel; Henein, Michael Y

    2013-07-31

    There is a significant relationship between the presence, extent and progression of coronary artery calcification (CAC) and cardiovascular (CV) events and mortality in both CV and renal patients and CAC scoring can provide improved predictive ability over risk factor scoring alone. There is also a close relationship between CAC presence and atherosclerotic plaque burden, with angiography studies showing very high sensitivity but poor specificity of CAC score for predicting obstructive disease. Nevertheless, there are objections to CAC screening because of uncertainties and lack of studies showing improved outcome. Furthermore, histopathology studies indicate that heavily calcified plaque is unlikely to result in a CV event, while the vulnerable plaque tends to be uncalcified or 'mixed', suggesting that calcification may be protective. This scenario highlights a number of paradoxes, which may indicate that the association between CAC and CV events is spurious, following from the adoption of CAC as a surrogate for high plaque burden, which itself is a surrogate for the presence of vulnerable plaque. Since studies indicate that arterial calcification is a complex, organised and regulated process similar to bone formation, there is no particular reason why it should be a reliable indicator of either the plaque burden or the risk of a future CV event. We suggest that it is time to divorce arterial calcification from atherosclerosis and to view it as a distinct pathology in its own right, albeit one which frequently coexists with atherosclerosis and is related to it for reasons which are not yet fully understood.

  12. Aircraft type influence on contrail properties

    NASA Astrophysics Data System (ADS)

    Jeßberger, P.; Voigt, C.; Schumann, U.; Sölch, I.; Schlager, H.; Kaufmann, S.; Petzold, A.; Schäuble, D.; Gayet, J.-F.

    2013-05-01

    The investigation of the impact of aircraft parameters on contrail properties helps to better understand the climate impact from aviation. Yet, in observations, it is a challenge to separate aircraft and meteorological influences on contrail formation. During the CONCERT campaign in November 2008, contrails from 3 Airbus passenger aircraft of type A319-111, A340-311 and A380-841 were probed at cruise under similar meteorological conditions with in-situ instruments on board the DLR research aircraft Falcon. Within the 2 min old contrails detected near ice saturation, we find similar effective diameters Deff (5.2-5.9 μm), but differences in particle number densities nice (162-235 cm-3) and in vertical contrail extensions (120-290 m), resulting in large differences in contrail optical depths τ (0.25-0.94). Hence larger aircraft produce optically thicker contrails. Based on the observations, we apply the EULAG-LCM model with explicit ice microphysics and in addition the Contrail and Cirrus Prediction model CoCiP to calculate the aircraft type impact on young contrails under identical meteorological conditions. The observed increase in τ for heavier aircraft is confirmed by the models, yet for generally smaller τ. An aircraft dependence of climate relevant contrail properties persists during contrail lifetime, adding importance to aircraft dependent model initialization. We finally derive an analytical relationship between contrail, aircraft and meteorological parameters. Near ice saturation, contrail width × τ scales linearly with fuel flow rate as confirmed by observations. For higher saturation ratios approximations from theory suggest a non-linear increase in the form (RHI-1)2/3. Summarized our combined results could help to more accurately assess the climate impact from aviation using an aircraft dependent contrail parameterization.

  13. Aircraft type influence on contrail properties

    NASA Astrophysics Data System (ADS)

    Jeßberger, P.; Voigt, C.; Schumann, U.; Sölch, I.; Schlager, H.; Kaufmann, S.; Petzold, A.; Schäuble, D.; Gayet, J.-F.

    2013-12-01

    The investigation of the impact of aircraft parameters on contrail properties helps to better understand the climate impact from aviation. Yet, in observations, it is a challenge to separate aircraft and meteorological influences on contrail formation. During the CONCERT campaign in November 2008, contrails from 3 Airbus passenger aircraft of types A319-111, A340-311 and A380-841 were probed at cruise under similar meteorological conditions with in situ instruments on board DLR research aircraft Falcon. Within the 2 min-old contrails detected near ice saturation, we find similar effective diameters Deff (5.2-5.9 μm), but differences in particle number densities nice (162-235 cm-3) and in vertical contrail extensions (120-290 m), resulting in large differences in contrail optical depths τ at 550 nm (0.25-0.94). Hence larger aircraft produce optically thicker contrails. Based on the observations, we apply the EULAG-LCM model with explicit ice microphysics and, in addition, the Contrail and Cirrus Prediction (CoCiP) model to calculate the aircraft type impact on young contrails under identical meteorological conditions. The observed increase in τ for heavier aircraft is confirmed by the models, yet for generally smaller τ. CoCiP model results suggest that the aircraft dependence of climate-relevant contrail properties persists during contrail lifetime, adding importance to aircraft-dependent model initialization. We finally derive an analytical relationship between contrail, aircraft and meteorological parameters. Near ice saturation, contrail width × τ scales linearly with the fuel flow rate, as confirmed by observations. For higher relative humidity with respect to ice (RHI), the analytical relationship suggests a non-linear increase in the form (RHI-12/3. Summarized, our combined results could help to more accurately assess the climate impact from aviation using an aircraft-dependent contrail parameterization.

  14. Genetics and molecular biology of brain calcification.

    PubMed

    Deng, Hao; Zheng, Wen; Jankovic, Joseph

    2015-07-01

    Brain calcification is a common neuroimaging finding in patients with neurological, metabolic, or developmental disorders, mitochondrial diseases, infectious diseases, traumatic or toxic history, as well as in otherwise normal older people. Patients with brain calcification may exhibit movement disorders, seizures, cognitive impairment, and a variety of other neurologic and psychiatric symptoms. Brain calcification may also present as a single, isolated neuroimaging finding. When no specific cause is evident, a genetic etiology should be considered. The aim of the review is to highlight clinical disorders associated with brain calcification and provide summary of current knowledge of diagnosis, genetics, and pathogenesis of brain calcification.

  15. Review article: Getting the balance right: assessing causes and extent of vascular calcification in chronic kidney disease.

    PubMed

    Ketteler, Markus; Biggar, Patrick H

    2009-06-01

    Vascular calcification is part of the definition of chronic kidney disease-mineral and bone disorder (CKD-MBD). It is also a surrogate parameter of cardiovascular and all-cause mortality risk in the CKD population. However, vascular calcification is not a homogenous entity, but a rather complex manifestation influenced by derangements of calcium and phosphate homeostasis, by dysregulated calcification inhibitors and promoters, and by the type of arterial disease (atherosclerosis vs arteriosclerosis). Despite the clear-cut risk association between the presence of vascular calcification and mortality, it is currently not well defined, how this knowledge about calcification should be translated into active clinical management. Further, the choice of the appropriate imaging test is a matter of debate. This article attempts to provide an update on insights into the pathophysiology of vascular calcification processes and a subjective view of the clinical consequences of management of CKD patients at risk. PMID:19563380

  16. Influence of liquid lubricant properties on their performance

    NASA Technical Reports Server (NTRS)

    Wedeven, V.

    1972-01-01

    The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation. Since the lubrication of practical surfaces usually involves boundary as well as hydrodynamic mechanisms, both the chemical and physical properties significantly influence the lubricant's performance.

  17. Calcific retropharyngeal tendinitis. [Radiological findings

    SciTech Connect

    Karasick, D.; Karasick, S.

    1981-12-01

    Calcific retropharyngeal tendinitis is an imflammation of the longus colli muscle tendon which is located on the anterior surface of the verterbral column extending from the atlas to the third thoracic vertebra. The acute inflammatory condition is selflimiting with symptoms consisting of a gradually increasing neck pain often associated with throat pain and difficulty swallowing. The pain is aggravated by head and neck movement. Clinically the condition can be confused with retropharyngeal absecess, meningitis, infectious spondylitis, and post-traumatic muscle spasm. The radiographic features of this condition consist of pre-vertebral soft tissue swelling from C1 to C4 and amorphous calcific density in the longus colli tendon anterior to the body of C2 and inferior to the anterior arch of C1.

  18. Low cloud properties influenced by cosmic rays

    PubMed

    Marsh; Svensmark

    2000-12-01

    The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (

  19. [Atherosclerotic calcification of coronary artery detected by electron beam CT: A new probation of calcific algorithm].

    PubMed

    Li, Wensheng; Song, Zhijian; Zhao, Shumin; Zuo, Huanchen

    2006-08-01

    Electron beam computed tomography (EBCT) can detect the atherosclerotic calcification of coronary artery qualitatively and quantitatively. It was also verified that the atherosclerotic calcification was directly related to the atherosclerotic extent and had a limited relation to the occurrence of coronary heart disease (CHD). So EBCT is one of the good non-invasive methods for predicting the risk of CHD. However, there are some problems in the calcification parameters (calcification area, calcification score) adopted by EBCT which have high variability and low reproducibility. As a result, these parameters have imperfection and need to be improved further. This research provides a new calcification parameter (calcification volume) which makes the use of three dimensional information of all calcific pixels in EBCT scanning images of coronary artery. After experiment in 11 human coronary artery specimens, it was testified that calcification volume had a lower variability than calcification area and calcification score in 25% percentile, median, 75% percentile, Mean, respectively. P value of t test in Mean variability is 0.027, and 0.058. These results suggest that calcification volume may be a new calcification parameter. PMID:17002127

  20. Pleural calcification in northwest Greece

    SciTech Connect

    Bazas, T.; Oakes, D.; Gilson, J.C.; Bazas, B.; McDonald, J.C.

    1985-12-01

    Mass miniature radiography in 1969 detected a high prevalence of pleural calcification in three villages in northwest Greece. In 1980 a survey of a 15% sample of the population over the age of 10 was carried out with a 80% response rate. Full-size radiographs, ventilatory capacity measurements, and a detailed questionnaire on respiratory symptoms, type of work, and residence were used. Independent classification of the 408 films by two readers using the ILO/UC scheme showed very few small opacities but a very high prevalence of pleural calcification first evident in young adults and rising to 70% in the elderly. The overall prevalence was 34.7% in men and 21.5% in women. A comparison with the 1969 survey showed a progression rate of 5% per annum. In neither sex was there a significant relation of pleural calcification to smoking, ventilatory capacity, nor type of work, though those classified as field croppers had a slightly higher prevalence. There was no obvious evidence of increased lung cancer or mesothelioma in the village. The agent responsible for this apparently benign condition was not identified.

  1. Molecular determinants of vascular calcification: a bench to bedside view.

    PubMed

    Dellegrottaglie, S; Sanz, J; Rajagopalan, S

    2006-08-01

    Vascular calcification (VC) is an orchestrated event, evoking the programmed process of the osteogenesis and triggered by inflammatory cytokines active at vascular level. VC is a dynamic process in which the vessel wall intima, media and also cardiac valves may be involved. Intimal calcification is an endochondral ossification process in which type II collagen is mineralized by calcium deposition. In contrast, an intra-membranous ossification process leads to medial calcification, while a dystrophic calcification process is responsible for valvular calcification. Mechanisms involved in VC may be summarized as: 1. Activation of osteogenesis in the vessel wall, 2. Loss of inhibitory factors, 3. Enhanced bone turnover, and 4. Abnormalities in mineral metabolism. The signaling axis constituted by osteoprotegerin (OPG), receptor activator nuclear factor kB (RANK) and its ligand (RANKL), along with the monocyte colony stimulating factor (M-CSF) and the transcription factor core Binding protein (Cbfa-1), play a pivotal role in the control of VC. In contrast, fetuin-A, matrix G1a protein (MGP) and osteopontin (OPN) control the inhibition of VC. In addition, abnormal mineral metabolism with enhanced phosphates availability favors calcium deposition. The inflammatory cytokines interleukin (IL-1) and tumor necrosis factor (TNF)-alpha enhance OPG and RANKL function in the vessel wall leading to VC. VC is a controlled process, depending on the balance between osteoblastic and osteoclastic influences and further modulated by the influence of risk factors like diabetes, smoking, age, hypertension and dyslipidemia. Recent advances in diagnostic tools such as with multi-detector computed tomography (MDCT) and electron beam computed tomography (EBCT), may help diagnosis and delineation of VC in the clinical setting and aid in understanding its prognostic value. PMID:16918372

  2. Vascular diseases: aortitis, aortic aneurysms, and vascular calcification.

    PubMed

    Ladich, Elena; Yahagi, Kazuyuki; Romero, Maria E; Virmani, Renu

    2016-01-01

    Inflammatory diseases of the aorta broadly include noninfectious and infectious aortitis, periaortitis, atherosclerosis, and inflammatory atherosclerotic aneurysms. Aortitis is uncommon but is increasingly recognized as an important cause of aortic aneurysms and dissections. Abdominal (AAA) and thoracic aortic aneurysms (TAA) have different pathologies and etiologies. AAAs are the most common type of aortic aneurysm, and the vast majority of these are atherosclerotic. The causes of TAA vary depending on the site of involvement, but medial degeneration is a common pathologic substrate, regardless of etiology, and genetic influences play a prominent role in TAA expression. Standardized classification schemes for inflammatory and degenerative diseases of the aorta have only recently been added to the pathology literature. A brief overview of the new histopathologic classifications for aortic inflammatory and degenerative diseases has recently been published by the Society for Cardiovascular Pathology and the Association for European Cardiovascular Pathology as a consensus document on the surgical pathology of the aorta. Vascular calcification is a highly regulated biologic process, and the mechanisms leading to vascular calcification are under investigation. Calcification may occur in the intima (atherosclerotic) or in the media secondary to metabolic disease. Rarely, vascular calcification may be associated with genetic disorders. PMID:27526100

  3. Incidental Anterior Cruciate Ligament Calcification: Case Report

    PubMed Central

    Hayashi, Hisami; Fischer, Hans

    2016-01-01

    The calcification of knee ligaments is a finding noted only in a handful of case reports. The finding of an anterior cruciate ligament calcification has been reported once in the literature. Comparable studies involving the posterior cruciate ligament, medial collateral ligament and an ossicle within the anterior cruciate ligament are likewise discussed in reports of symptomatic patients. We report a case of incidentally discovered anterior cruciate ligament calcification. We discuss the likely etiology and clinical implications of this finding. PMID:27200163

  4. Incidental Anterior Cruciate Ligament Calcification: Case Report.

    PubMed

    Hayashi, Hisami; Fischer, Hans

    2016-03-01

    The calcification of knee ligaments is a finding noted only in a handful of case reports. The finding of an anterior cruciate ligament calcification has been reported once in the literature. Comparable studies involving the posterior cruciate ligament, medial collateral ligament and an ossicle within the anterior cruciate ligament are likewise discussed in reports of symptomatic patients. We report a case of incidentally discovered anterior cruciate ligament calcification. We discuss the likely etiology and clinical implications of this finding.

  5. The Role of AGE/RAGE Signaling in Diabetes-Mediated Vascular Calcification

    PubMed Central

    2016-01-01

    AGE/RAGE signaling has been a well-studied cascade in many different disease states, particularly diabetes. Due to the complex nature of the receptor and multiple intersecting pathways, the AGE/RAGE signaling mechanism is still not well understood. The purpose of this review is to highlight key areas of AGE/RAGE mediated vascular calcification as a complication of diabetes. AGE/RAGE signaling heavily influences both cellular and systemic responses to increase bone matrix proteins through PKC, p38 MAPK, fetuin-A, TGF-β, NFκB, and ERK1/2 signaling pathways in both hyperglycemic and calcification conditions. AGE/RAGE signaling has been shown to increase oxidative stress to promote diabetes-mediated vascular calcification through activation of Nox-1 and decreased expression of SOD-1. AGE/RAGE signaling in diabetes-mediated vascular calcification was also attributed to increased oxidative stress resulting in the phenotypic switch of VSMCs to osteoblast-like cells in AGEs-induced calcification. Researchers found that pharmacological agents and certain antioxidants decreased the level of calcium deposition in AGEs-induced diabetes-mediated vascular calcification. By understanding the role the AGE/RAGE signaling cascade plays diabetes-mediated vascular calcification will allow for pharmacological intervention to decrease the severity of this diabetic complication. PMID:27547766

  6. Calcification, storm damage and population resilience of tabular corals under climate change.

    PubMed

    Madin, Joshua S; Hughes, Terry P; Connolly, Sean R

    2012-01-01

    Two facets of climate change--increased tropical storm intensity and ocean acidification--are expected to detrimentally affect reef-building organisms by increasing their mortality rates and decreasing their calcification rates. Our current understanding of these effects is largely based on individual organisms' short-term responses to experimental manipulations. However, predicting the ecologically-relevant effects of climate change requires understanding the long-term demographic implications of these organism-level responses. In this study, we investigate how storm intensity and calcification rate interact to affect population dynamics of the table coral Acropora hyacinthus, a dominant and geographically widespread ecosystem engineer on wave-exposed Indo-Pacific reefs. We develop a mechanistic framework based on the responses of individual-level demographic rates to changes in the physical and chemical environment, using a size-structured population model that enables us to rigorously incorporate uncertainty. We find that table coral populations are vulnerable to future collapse, placing in jeopardy many other reef organisms that are dependent upon them for shelter and food. Resistance to collapse is largely insensitive to predicted changes in storm intensity, but is highly dependent on the extent to which calcification influences both the mechanical properties of reef substrate and the colony-level trade-off between growth rate and skeletal strength. This study provides the first rigorous quantitative accounting of the demographic implications of the effects of ocean acidification and changes in storm intensity, and provides a template for further studies of climate-induced shifts in ecosystems, including coral reefs.

  7. Calcification in bleached and unbleached Montastraea faveolata: evaluating the role of oxygen and glycerol

    NASA Astrophysics Data System (ADS)

    Colombo-Pallotta, M. F.; Rodríguez-Román, A.; Iglesias-Prieto, R.

    2010-12-01

    All reef-building corals are symbiotic with dinoflagellates of the genus Symbiodinium, which influences many aspects of the host’s physiology including calcification. Coral calcification is a biologically controlled process performed by the host that takes place several membranes away from the site of photosynthesis performed by the symbiont. Although it is well established that light accelerates CaCO3 deposition in reef-building corals (commonly referred to as light-enhanced calcification), the complete physiological mechanism behind the process is not fully understood. To better comprehend the coral calcification process, a series of laboratory experiments were conducted in the major Caribbean reef-building species Montastraea faveolata, to evaluate the effect of glycerol addition and/or the super-saturation of oxygen in the seawater. These manipulations were performed in bleached and unbleached corals, to separate the effect of photosynthesis from calcification. The results suggest that under normal physiological conditions, a 42% increase in seawater oxygen concentration promotes a twofold increase in dark-calcification rates relative to controls. On the other hand, the results obtained using bleached corals suggest that glycerol is required, as a metabolic fuel, in addition to an oxygenic environment in a symbiosis that has been disrupted. Also, respiration rates in symbiotic corals that were pre-incubated in light conditions showed a kinetic limitation, whereas corals that were pre-incubated in darkness were oxygen limited, clearly emphasizing the role of oxygen in this regard. These findings indicate that calcification in symbiotic corals is not strictly a “light-enhanced” or “dark-repressed” process, but rather, the products of photosynthesis have a critical role in calcification, which should be viewed as a “photosynthesis-driven” process. The results presented here are discussed in the context of the current knowledge of the coral

  8. [Multiple calcifications and ossifications of tendons].

    PubMed

    Gaucher, A; Péré, P; Gillet, P

    1991-06-21

    Multiple calcifications and ossifications of tendons are, as a rule, associated with similar lesions of other articular and/or periarticular structures. The nature and multiplicity of these lesions gives them an unquestionable diagnostic and nosological value. Multiple calcifications are part of the apatite arthritis or of diffuse articular chondrocalcinosis. Multiple ossifications of tendons often suggest Forestier's disease and ankylosing spondylitis.

  9. Urease-induced calcification of segmented polymer hydrogels - a step towards artificial biomineralization.

    PubMed

    Rauner, Nicolas; Meuris, Monika; Dech, Stephan; Godde, Julia; Tiller, Joerg C

    2014-09-01

    Natural organic/inorganic composites, such as nacre, bones and teeth, are perfectly designed materials with exceptional mechanical properties. Numerous approaches have been taken to synthetically prepare such composites. The presented work describes a new way of mineralizing bulk materials on a large scale following the approach of bioinduced mineralization. To this end, a series of polymer conetworks with entrapped urease were prepared. After polymerization, the entrapped urease shows high enzymatic activity. The bioactive polymer conetworks were then treated with an aqueous mixture of urea and CaCl2. The urease-induced calcification indeed allows formation of carbonate crystals exclusively within the hydrogel even at room temperature. The influence of network composition, degree of cross-linking, immobilized urease concentration and temperature of calcification were investigated. By varying these parameters, spherical, monolithic clusters, as well as bar-like nanocrystals with different aspect ratios in spherical or dendritic arrays, are formed. The grown nanocrystals improve the stiffness of the starting material by up to 700-fold, provided that the microstructure shows a dense construction without pores and strong interaction between crystals and network. The process has the potential to generate a new class of hybrid materials that would be available on the macroscopic scale for use in lightweight design and medicine.

  10. Neomycin fixation followed by ethanol pretreatment leads to reduced buckling and inhibition of calcification in bioprosthetic valves.

    PubMed

    Raghavan, Devanathan; Shah, Sagar R; Vyavahare, Naren R

    2010-01-01

    Glutaraldehyde crosslinked bioprosthetic heart valves (BHVs) have two modalities of failure: degeneration (cuspal tear due to matrix failure) and calcification. They can occur independently as well as one can lead to the other causing co-existence. Calcific failure has been extensively studied before and several anti-calcification treatments have been developed; however, little research is directed to understand mechanisms of valvular degeneration. One of the shortcomings of glutaraldehyde fixation is its inability to stabilize all extracellular matrix components in the tissue. Previous studies from our lab have demonstrated that neomycin could be used as a fixative to stabilize glycosaminoglycans (GAGs) present in the valve to improve matrix properties. But neomycin fixation did not prevent cuspal calcification. In the present study, we wanted to enhance the anti-calcification potential of neomycin fixed valves by pre-treating with ethanol or removing the free aldehydes by sodium borohydride treatment. Ethanol treatment has been previously used and found to have excellent anti-calcification properties for valve cusps. Results demonstrated in this study suggest that neomycin followed by ethanol treatment effectively preserves GAGs both in vitro as well as in vivo after subdermal implantation in rats. In vivo calcification was inhibited in neomycin fixed cusps pretreated with ethanol compared to glutaraldehyde (GLUT) control. Sodium borohydride treatment by itself did not inhibit calcification nor stabilized GAGs against enzymatic degradation. Neomycin fixation followed by ethanol treatment of BHVs could prevent both modalities of failure, thereby increasing the effective durability and lifetime of these bioprostheses several fold.

  11. Factors Influencing the Dielectric Properties of Agricultural and Food Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dielectric properties of materials are defined, and the major factors that influence these properties of agricultural and food materials, namely, frequency of the applied radio-frequency or microwave electric fields, and water content, temperature, and density of the materials, are discussed on the ...

  12. Calcific tendinitis of the shoulder

    PubMed Central

    DE CARLI, ANGELO; PULCINELLI, FERDINANDO; ROSE, GIACOMO DELLE; PITINO, DARIO; FERRETTI, ANDREA

    2014-01-01

    Calcific tendinitis is a common disease that predominantly affects individuals aged between 40 and 60 years. Women seem to be more affected than men. Various factors have been suggested to play a role in this condition, such as abnormal activity of the thyroid gland, metabolic diseases (e.g. diabetes), and genetic predisposition. Various etiological hypotheses have been advanced: the degenerative and multiphasic theories are the two most accredited ones. Clinically, calcific tendinitis is characterized by severe, disabling pain which occurs spontaneously, usually in the morning. There can be concomitant stiffness, giving rise to a frozen shoulder-like clinical picture. Conventional radiography of the shoulder is the most appropriate imaging approach. Most cases resolve spontaneously. Many conservative treatments have been reported in the literature, showing varying levels of evidence of efficacy. Arthroscopic surgery is the orthopedic specialist’s last option. It is to be noted that post-surgical pain can persist for many weeks after the operation. Finally, it is important not to forget the variant characterized by osteolytic involvement of the greater tuberosity, which has been associated with a worse clinical outcome, both after conservative treatment and after surgery. PMID:25606556

  13. Physiopathology of intratendinous calcific deposition

    PubMed Central

    2012-01-01

    In calcific tendinopathy (CT), calcium deposits in the substance of the tendon, with chronic activity-related pain, tenderness, localized edema and various degrees of decreased range of motion. CT is particularly common in the rotator cuff, and supraspinatus, Achilles and patellar tendons. The presence of calcific deposits may worsen the clinical manifestations of tendinopathy with an increase in rupture rate, slower recovery times and a higher frequency of post-operative complications. The aetiopathogenesis of CT is still controversial, but seems to be the result of an active cell-mediated process and a localized attempt of the tendon to compensate the original decreased stiffness. Tendon healing includes many sequential processes, and disturbances at different stages of healing may lead to different combinations of histopathological changes, diverting the normal healing processes to an abnormal pathway. In this review, we discuss the theories of pathogenesis behind CT. Better understanding of the pathogenesis is essential for development of effective treatment modalities and for improvement of clinical outcomes. PMID:22917025

  14. Mechanisms and Clinical Consequences of Vascular Calcification

    PubMed Central

    Zhu, Dongxing; Mackenzie, Neil C. W.; Farquharson, Colin; MacRae, Vicky E.

    2012-01-01

    Vascular calcification has severe clinical consequences and is considered an accurate predictor of future adverse cardiovascular events, including myocardial infarction and stroke. Previously vascular calcification was thought to be a passive process which involved the deposition of calcium and phosphate in arteries and cardiac valves. However, recent studies have shown that vascular calcification is a highly regulated, cell-mediated process similar to bone formation. In this article, we outline the current understanding of key mechanisms governing vascular calcification and highlight the clinical consequences. By understanding better the molecular pathways and genetic circuitry responsible for the pathological mineralization process novel drug targets may be identified and exploited to combat and reduce the detrimental effects of vascular calcification on human health. PMID:22888324

  15. MicroRNAs Regulate Vascular Medial Calcification.

    PubMed

    Leopold, Jane A

    2014-01-01

    Vascular calcification is highly prevalent in patients with coronary artery disease and, when present, is associated with major adverse cardiovascular events, including an increased risk of cardiovascular mortality. The pathogenesis of vascular calcification is complex and is now recognized to recapitulate skeletal bone formation. Vascular smooth muscle cells (SMC) play an integral role in this process by undergoing transdifferentiation to osteoblast-like cells, elaborating calcifying matrix vesicles and secreting factors that diminish the activity of osteoclast-like cells with mineral resorbing capacity. Recent advances have identified microRNAs (miRs) as key regulators of this process by directing the complex genetic reprogramming of SMCs and the functional responses of other relevant cell types relevant for vascular calcification. This review will detail SMC and bone biology as it relates to vascular calcification and relate what is known to date regarding the regulatory role of miRs in SMC-mediated vascular calcification.

  16. Diagnosis and differential diagnosis of breast calcifications

    SciTech Connect

    Lanyi, M.

    1987-01-01

    This book is the result of more than 10 years' intensive research into the phenomena of breast calcifications. The author, himself a decisive figure in the development of mammography, demonstrates that a careful, detailed analysis of X-rays can lead to a high degree of diagnostic certainty. Indeed, Lanyi's descriptions make one ask why mammography, which originally awakened such high hopes, is given so little attention today. Contents: historical review; critical analysis of the literature; statement of problems and goals; instruments used in the evaluation of breast microcalcifications; remarks on the pathogenesis, pathophysiology, and composition of breast calcifications; calcifications within the lobular and ductal system of the breast; calcifications in intra- and pericanalicular fibroadenomas; calcifications outside the lobular and ductal systems of the breast; differential diagnosis of microcalcifications; clinically occult, mammographically suspicious microcalcification cluster: Pre-, intra-, and postoperative measures; references, and index.

  17. Calcification inhibitors in human ligamentum flavum.

    PubMed

    Maruta, K; Ichimura, K; Matsui, H; Yamagami, T; Sano, A; Tsuji, H

    1993-01-01

    To examine the presence of substances which inhibit calcification in human ligamentum flavum, the inhibitory effect of an Na2HPO4 extract of the flavum was determined in terms of the in vitro calcium uptake of the ligamentum flavum matrix. Additionally, grafts of extracted and non-extracted dry ligamentum flavum matrices were transplanted into the dorsal muscles of rats, and calcification in the grafts was examined radiologically and histochemically. In order to determine if component cells of human ligamentum flavum produce calcification inhibitors, ligamentum flavum cells were cultured, and the crystal inhibitor activity of the culture medium was measured by a seed test which used hydroxyapatite as the nucleus of precipitation. The calcification reaction system demonstrated that the ligamentum flavum extract contains an inhibitory factor for calcium uptake by the ligamentum flavum matrix. The seed test revealed that human ligamentum flavum cells produce calcification inhibitor activity.

  18. Mechanisms of vascular calcification and associated diseases.

    PubMed

    Marulanda, Juliana; Alqarni, Saleh; Murshed, Monzur

    2014-01-01

    Mineralization of bone and tooth extracellular matrix (ECM) is a physiologic process, while soft tissue mineralization, also known as ectopic mineralization (calcification), is a pathologic condition. Vascular calcification is common in aging and also in a number of genetic and metabolic disorders. The calcific deposits in arteries complicate the prognosis and increase the morbidity in diseases such as atherosclerosis, diabetes and chronic kidney disease (CKD). To completely understand the pathophysiology of these lifethreatening diseases, it is critical to elucidate the molecular mechanisms underlying vascular calcification. Unveiling these mechanisms will eventually identify new therapeutic targets and also improve the management of the associated complications. In the current review, we discussed the common determinants of ECM mineralization, the mechanism of vascular calcification associated with several human diseases and outlined the most common therapeutic approaches to prevent its progression.

  19. Abdominal calcifications in infants and children.

    PubMed

    Pintér, A B; Weisenbach, J; Szemlédy, F

    1984-12-01

    Abdominal and pelvic calcifications are usually incidental findings and require further measures to determine their origin. Most laboratory investigations are of little help. Plain anteroposterior and lateral x-rays are essential. The time of appearance and localisation of a calcification is of diagnostic importance. Amorphous, granular and irregular calcification can be an early sign of malignancy. Mobility of a calcification also helps to clarify its origin. Over the past 15 years abdominal and pelvic calcifications, excluding urological radiodensities, have been found in 63 patients up to fourteen years of age at our institute. A migrating deposit in the omentum, a spontaneously amputated calcified ovary mimicking a vesical calculus and a congenital retroperitoneal xanthofibroma caused the greatest difficulty in establishing a preoperative diagnosis.

  20. Calcification

    MedlinePlus

    ... soft tissue tumors. In: Kumar V, Abbas AK, Aster JC, eds. Robbins and Cotran Pathologic Basis of ... Saunders; 2015:chap 26. Kumar V, Abbas AK, Aster JC. Cellular responses to stress and toxic insults: ...

  1. Influence of liquid lubricant properties on their performance.

    NASA Technical Reports Server (NTRS)

    Wedeven, V.

    1972-01-01

    The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation.

  2. Effect of trace metal availability on coccolithophorid calcification.

    PubMed

    Schulz, K G; Zondervan, I; Gerringa, L J A; Timmermans, K R; Veldhuis, M J W; Riebesell, U

    2004-08-01

    The deposition of atmospheric dust into the ocean has varied considerably over geological time. Because some of the trace metals contained in dust are essential plant nutrients which can limit phytoplankton growth in parts of the ocean, it has been suggested that variations in dust supply to the surface ocean might influence primary production. Whereas the role of trace metal availability in photosynthetic carbon fixation has received considerable attention, its effect on biogenic calcification is virtually unknown. The production of both particulate organic carbon and calcium carbonate (CaCO3) drives the ocean's biological carbon pump. The ratio of particulate organic carbon to CaCO3 export, the so-called rain ratio, is one of the factors determining CO2 sequestration in the deep ocean. Here we investigate the influence of the essential trace metals iron and zinc on the prominent CaCO3-producing microalga Emiliania huxleyi. We show that whereas at low iron concentrations growth and calcification are equally reduced, low zinc concentrations result in a de-coupling of the two processes. Despite the reduced growth rate of zinc-limited cells, CaCO3 production rates per cell remain unaffected, thus leading to highly calcified cells. These results suggest that changes in dust deposition can affect biogenic calcification in oceanic regions characterized by trace metal limitation, with possible consequences for CO2 partitioning between the atmosphere and the ocean.

  3. Coccolithophore calcification response to past ocean acidification and climate change

    PubMed Central

    O’Dea, Sarah A.; Gibbs, Samantha J.; Bown, Paul R.; Young, Jeremy R.; Poulton, Alex J.; Newsam, Cherry; Wilson, Paul A.

    2014-01-01

    Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene–Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates. However, only Coccolithus pelagicus exhibits a transient thinning of coccoliths, immediately before the PETM, that may have been OA-induced. Changing coccolith thickness may affect calcite production more significantly in the dominant modern species Emiliania huxleyi, but, overall, these PETM records indicate that the environmental factors that govern taxonomic composition and growth rate will most strongly influence coccolithophore calcification response to anthropogenic change. PMID:25399967

  4. Coccolithophore calcification response to past ocean acidification and climate change.

    PubMed

    O'Dea, Sarah A; Gibbs, Samantha J; Bown, Paul R; Young, Jeremy R; Poulton, Alex J; Newsam, Cherry; Wilson, Paul A

    2014-01-01

    Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene-Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates. However, only Coccolithus pelagicus exhibits a transient thinning of coccoliths, immediately before the PETM, that may have been OA-induced. Changing coccolith thickness may affect calcite production more significantly in the dominant modern species Emiliania huxleyi, but, overall, these PETM records indicate that the environmental factors that govern taxonomic composition and growth rate will most strongly influence coccolithophore calcification response to anthropogenic change. PMID:25399967

  5. Coccolithophore calcification response to past ocean acidification and climate change.

    PubMed

    O'Dea, Sarah A; Gibbs, Samantha J; Bown, Paul R; Young, Jeremy R; Poulton, Alex J; Newsam, Cherry; Wilson, Paul A

    2014-11-17

    Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene-Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates. However, only Coccolithus pelagicus exhibits a transient thinning of coccoliths, immediately before the PETM, that may have been OA-induced. Changing coccolith thickness may affect calcite production more significantly in the dominant modern species Emiliania huxleyi, but, overall, these PETM records indicate that the environmental factors that govern taxonomic composition and growth rate will most strongly influence coccolithophore calcification response to anthropogenic change.

  6. IN718 Additive Manufacturing Properties and Influences

    NASA Technical Reports Server (NTRS)

    Lambert, Dennis M.

    2015-01-01

    The results of tensile, fracture, and fatigue testing of IN718 coupons produced using the selective laser melting (SLM) additive manufacturing technique are presented. The data has been "generalized" to remove the numerical values, although certain references to material standards are provided. This document provides some knowledge of the effect of variation of controlled build parameters used in the SLM process, a snapshot of the capabilities of SLM in industry at present, and shares some of the lessons learned along the way. For the build parameter characterization, the parameters were varied over a range about the machine manufacturer's recommended value, and in each case they were varied individually, although some co-variance of those parameters would be expected. SLM-produced IN718, tensile, fracture, and high-cycle fatigue properties equivalent to wrought IN718 are achievable. Build and post-build processes need to be determined and then controlled to established limits to accomplish this. It is recommended that a multi-variable evaluation, e.g., design-of-experiment (DOE), of the build parameters be performed to better evaluate the co-variance of the parameters.

  7. IN718 Additive Manufacturing Properties and Influences

    NASA Technical Reports Server (NTRS)

    Lambert, Dennis M.

    2015-01-01

    The results of tensile, fracture, and fatigue testing of IN718 coupons produced using the selective laser melting (SLM) additive manufacturing technique are presented. The data have been "sanitized" to remove the numerical values, although certain references to material standards are provided. This document provides some knowledge of the effect of variation of controlled build parameters used in the SLM process, a snapshot of the capabilities of SLM in industry at present, and shares some of the lessons learned along the way. For the build parameter characterization, the parameters were varied over a range that was centered about the machine manufacturer's recommended value, and in each case they were varied individually, although some co-variance of those parameters would be expected. Tensile, fracture, and high-cycle fatigue properties equivalent to wrought IN718 are achievable with SLM-produced IN718. Build and post-build processes need to be determined and then controlled to established limits to accomplish this. It is recommended that a multi-variable evaluation, e.g., design-of experiment (DOE), of the build parameters be performed to better evaluate the co-variance of the parameters.

  8. Evidence of Pineal Gland Calcification on CBCT is Not Insignificant: What Else You Might Discover about Your Patient.

    PubMed

    Fore, Stacy

    2016-01-01

    The use of CBCT technology in the dental office is increasing rapidly. These scans provide information on anatomy not previously evaluated with traditional 2D films. One structure often mentioned in a CBCT radiology report is the pineal gland. The pineal gland will show evidence of calcification, but this calcification is often dismissed as a normal aging process. This review of the function and influence of the pineal gland may influence the doctor to complete further evaluation of the patient.

  9. Evidence of Pineal Gland Calcification on CBCT is Not Insignificant: What Else You Might Discover about Your Patient.

    PubMed

    Fore, Stacy

    2016-01-01

    The use of CBCT technology in the dental office is increasing rapidly. These scans provide information on anatomy not previously evaluated with traditional 2D films. One structure often mentioned in a CBCT radiology report is the pineal gland. The pineal gland will show evidence of calcification, but this calcification is often dismissed as a normal aging process. This review of the function and influence of the pineal gland may influence the doctor to complete further evaluation of the patient. PMID:27319034

  10. Notch signaling in cardiovascular disease and calcification.

    PubMed

    Rusanescu, Gabriel; Weissleder, Ralph; Aikawa, Elena

    2008-08-01

    Recent increase in human lifespan has shifted the spectrum of aging-related disorders to an unprecedented upsurge in cardiovascular diseases, especially calcific aortic valve stenosis, which has an 80% risk of progression to heart failure and death. A current therapeutic option for calcified valves is surgical replacement, which provides only temporary relief. Recent progress in cardiovascular research has suggested that arterial and valve calcification are the result of an active process of osteogenic differentiation, induced by a pro-atherogenic inflammatory response. At molecular level, the calcification process is regulated by a network of signaling pathways, including Notch, Wnt and TGFbeta/BMP pathways, which control the master regulator of osteogenesis Cbfa1/Runx2. Genetic and in vitro studies have implicated Notch signaling in the regulation of macrophage activation and cardiovascular calcification. Individuals with inactivating Notch1 mutations have a high rate of cardiovascular disorders, including valve stenosis and calcification. This article reviews recent progress in the mechanism of cardiovascular calcification and discusses potential molecular mechanisms involved, focusing on Notch receptors. We propose a calcification model where extreme increases in vascular wall cell density due to inflammation-induced cell proliferation can trigger an osteogenic differentiation program mediated by Notch receptors. PMID:19936191

  11. The influence of the nanostructure geometry on the thermoelectric properties

    NASA Astrophysics Data System (ADS)

    AL-Badry, Lafy F.

    2016-09-01

    We discuss the influence of nanostructure geometry on the thermoelectric properties in quantum ring consists of one QD in each arm, each QD connects with side QD. The calculations are based on the time-dependent Hamiltonian model, the steady state is considered to obtain an analytical expression for the transmission probability as a function of system energies. We employed the transmission probability to calculate the thermoelectric properties. We investigate thermoelectric properties through three configurations of this nanostructure. Figure of merit enhanced in configuration (II) when side QD connected to upper arm of quantum ring. The magnetic flux threads quantum ring. The effect of magnetic flux on the thermoelectric properties is examined.

  12. Factors influencing the dielectric properties of agricultural and food products.

    PubMed

    Nelson, Stuart O; Trabelsi, Samir

    2012-01-01

    Dielectric properties of materials are defined, and the major factors that influence these properties of agricultural and food materials, namely, frequency of the applied radiofrequency or microwave electric fields, and water content, temperature, and density of the materials, are discussed on the basis of fundamental concepts. The dependence of measured dielectric properties on these factors is illustrated graphically and discussed for a number of agricultural and food products, including examples of grain, peanuts, fruit, eggs, fresh chicken meat, whey protein gel, and a macaroni and cheese preparation. General observations are provided on the nature of the variation of the dielectric properties with the major variables.

  13. Dystrophic calcification: A rare pediatric parotid mass.

    PubMed

    Chislett, Sean P; Liming, Bryan J; Rogers, Derek J

    2016-02-01

    Dystrophic calcification, the ectopic deposition of calcium in previously damaged or inflamed tissues, is an uncommon finding in the head and neck. Only a few cases have been reported in the parotidomasseteric region, and all of them have been located within and adjacent to the masseter. We present a case of dystrophic calcification occurring entirely within the parotid gland in a 7-year-old girl without apparent inciting inflammation, infection, or trauma. Our patient's presentation highlights the diagnostic challenge associated with parotid masses in the pediatric population. To our knowledge, this is the first reported case of dystrophic calcification occurring entirely within the parotid gland in a child. PMID:26810287

  14. Chondrocyte Apoptosis Is Not Essential for Cartilage Calcification: Evidence From an In Vitro Avian Model

    PubMed Central

    Pourmand, Eric P.; Binderman, Itzhak; Doty, Stephen B.; Kudryashov, Valery; Boskey, Adele L.

    2006-01-01

    The calcification of cartilage is an essential step in the process of normal bone growth through endochondral ossification. Chondrocyte apoptosis is generally observed prior to the transition of calcified cartilage to bone. There are, however, contradictory reports in the literature as to whether chondrocyte apoptosis is a precursor to cartilage calcification, a co-event, or occurs after calcification. The purpose of this study was to test the hypothesis that chondrocyte apoptosis is not a requirement for initial calcification using a cell culture system that mimics endochondral ossification. Mesenchymal stem cells harvested from Stages 21-23 chick limb buds were plated as micro-mass cultures in the presence of 4 mM inorganic phosphate (mineralizing conditions). The cultures were treated with either an apoptosis inhibitor or stimulator and compared to un-treated controls before the start of calcification on day 7. Inhibition of apoptosis with the caspase inhibitor Z-Val-Ala-Asp (O-Me)-fluoromethylketone (Z-VAD-fmk) caused no decreases in calcification as indicated by radioactive calcium uptake or Fourier transform infrared (FT-IR) analysis of mineral properties. When apoptosis was inhibited, the cultures showed more robust histological features (including more intense staining for proteoglycans, and more intact cells within the nodules as well as along the periphery of the cells as compared to untreated controls), more proliferation as noted by bromo-deoxyuridine (BrdU) labeling, decreases in terminal deoxynucleotidyl transferase (Tdt)-mediated dUTP nick-end labeling (TUNEL) staining, and fewer apoptotic bodies in electron microscopy. Stimulation of apoptosis with 40-120 nM staurosporine prior to the onset of calcification resulted in inhibition of calcium accretion, with the extent of total calcium uptake significantly decreased, the amount of matrix deposition impaired, and the formation of abnormal mineral crystals. These results indicate that chondrocyte

  15. The influence of the sterilisation process on certain thermal properties.

    PubMed

    Issa, Manal; Abreu, Maria Jose; Schacher, Laurence; Adolphe, Dominique; Cabeco Silva, Maria Elisabete

    2004-09-01

    Surgical clothing and sheets have to meet all the requirements set in the health-care industry regarding body comfort, absorption capacity and general recognition of physiological safety and sterilisation capacity. The disposable surgical gown market is growing and the demand will increase in all product groups and market sectors, where the health care industry is the most dynamic growth area. The aim of this study was to analyse some of the thermal properties of disposable surgical gowns before and after different sterilisation methods, and therefore the influence of the sterilisation process on their thermal comfort. The apparatus used to measure heat transfer properties was the Thermo Labo device (KES FB7) which evaluates the cool/warm sensation, thermal conductivity and insulation properties of the test item. The results obtained highlight the influence of the sterilisation process on the thermal and comfort properties.

  16. Consideration of coastal carbonate chemistry in understanding biological calcification

    NASA Astrophysics Data System (ADS)

    Fassbender, Andrea J.; Sabine, Christopher L.; Feifel, Kirsten M.

    2016-05-01

    Correlations between aragonite saturation state (ΩAr) and calcification have been identified in many laboratory manipulation experiments aiming to assess biological responses to ocean acidification (OA). These relationships have been used with projections of ΩAr under continued OA to evaluate potential impacts on marine calcifiers. Recent work suggests, however, that calcification in some species may be controlled by the ratio of bicarbonate to hydrogen ion, or the substrate-to-inhibitor ratio (SIR), rather than ΩAr. SIR and ΩAr are not always positively correlated in the natural environment, which means that ΩAr can be a poor indicator of the calcifying environment when ΩAr->1. Highly variable carbonate chemistry in the coastal zone challenges our ability to monitor fluctuations in ΩAr, SIR, and the ΩAr-SIR relationship making it difficult to assess biological OA exposures and vulnerability. Careful consideration of natural variability throughout ocean environments is required to accurately determine the influence of OA on biological calcification.

  17. Calcification provides mechanical reinforcement to whale baleen alpha-keratin.

    PubMed

    Szewciw, L J; de Kerckhove, D G; Grime, G W; Fudge, D S

    2010-09-01

    Hard alpha-keratins such as hair, nail, wool and horn are stiff epidermal appendages used by mammals in a variety of functions including thermoregulation, feeding and intraspecific competition. Hard alpha-keratins are fibre-reinforced structures consisting of cytoskeletal elements known as 'intermediate filaments' embedded in an amorphous protein matrix. Recent research has shown that intermediate filaments are soft and extensible in living keratinocytes but become far stiffer and less extensible in keratinized cells, and this stiffening may be mediated by air-drying. Baleen, the keratinous plates used by baleen whales during filter feeding, is an unusual mammalian keratin in that it never air dries, and in some species, it represents the most heavily calcified of all the hard alpha-keratins. We therefore tested the hypothesis that whale baleen is stiffened by calcification. Here, we provide, to our knowledge, the first comprehensive description of baleen material properties and show that calcification contributes to overcoming the shortcomings of stiffening this hard alpha-keratin without the benefit of air-drying. We also demonstrate striking interspecies differences in the calcification patterns among three species of baleen whales and provide novel insights into the function and evolution of this unusual biomaterial.

  18. Coral calcification in a changing ocean

    USGS Publications Warehouse

    Kuffner, Ilsa B.

    2010-01-01

    One of the goals of the Coral Reef Ecosystem Studies (CREST) project is to examine how calcification rates in reef-building corals and encrusting coralline algae are changing in response to changes in the ocean environment.

  19. Nanobacteria-associated calcific aortic valve stenosis.

    PubMed

    Jelic, Tomislav M; Chang, Ho-Huang; Roque, Rod; Malas, Amer M; Warren, Stafford G; Sommer, Andrei P

    2007-01-01

    Calcific aortic valve stenosis is the most common valvular disease in developed countries, and the major reason for operative valve replacement. In the US, the current annual cost of this surgery is approximately 1 billion dollars. Despite increasing morbidity and mortality, little is known of the cellular basis of the calcifications, which occur in high-perfusion zones of the heart. The case is presented of a patient with calcific aortic valve stenosis and colonies of progressively mineralized nanobacteria in the fibrocalcific nodules of the aortic cusps, as revealed by transmission electron microscopy. Consistent with their outstanding bioadhesivity, nanobacteria might serve as causative agents in the development of calcific aortic valve stenosis. PMID:17315391

  20. The relationship between pulp calcifications and salivary gland calcifications

    PubMed Central

    Kaswan, Sumita; Maheshwari, Sneha; Rahman, Farzan; Khandelwal, Suneet

    2014-01-01

    Aim: Pulp stones are discrete calcified bodies found in the dental pulp. Sialolithasis is the most common salivary gland disease. The aim of the present study was to determine the relationship between the pulp stones and salivary gland stones. Material and Methods: 196 patients were randomly selected from the out patient department for the study. The periapical radiographs for all patients were evaluated for the presence or absence of the narrowing of dental pulp chambers and pulp canals. The intra oral occlusal radiographs were also evaluated to determine the presence or absence of salivary stones. The results were compared and analyzed using the Chi-square test (p<0.001). Results: Salivary gland calcifications were detected in 5 patients. 191 patients had pulp narrowing and 118 patients had pulp stones. There was no statistical correlation between pulp narrowing and salivary stones (p>0.001) and also between pulp stones and salivary gland stones (p>0.001). Conclusions: However, the incidental findings of salivary gland stones on intra oral occlusal radiographs can provide useful information in the early diagnosis of the condition, but in the present study no significant relationship was found between the presence of pulp stones and salivary gland stones. Key words:Pulp stone, salivary gland stone, periapical radiograph, occlusal radiograph. PMID:25674311

  1. Influence of multiple categories on the prediction of unknown properties

    PubMed Central

    Verde, Michael F.; Murphy, Gregory L.; Ross, Brian H.

    2006-01-01

    Knowing an item's category helps us predict its unknown properties. Previous studies suggest that when asked to evaluate the probability of an unknown property, people tend to consider only an item's most likely category, ignoring alternative categories. In the present study, property prediction took the form of either a probability rating or a speeded, binary-choice judgment. Consistent with past findings, subjects ignored alternative categories in their probability ratings. However, their binary-choice judgments were influenced by alternative categories. This novel finding suggests that the way category knowledge is used in prediction depends critically on the form of the prediction. PMID:16156183

  2. Comparative histology of pineal calcification.

    PubMed

    Vígh, B; Szél, A; Debreceni, K; Fejér, Z; Manzano e Silva, M J; Vígh-Teichmann, I

    1998-07-01

    The pineal organ (pineal gland, epiphysis cerebri) contains several calcified concretions called "brain sand" or acervuli (corpora arenacea). These concretions are conspicuous with imaging techniques and provide a useful landmark for orientation in the diagnosis of intracranial diseases. Predominantly composed of calcium and magnesium salts, corpora arenacea are numerous in old patients. In smaller number they can be present in children as well. The degree of calcification was associated to various diseases. However, the presence of calcified concretions seems not to reflect a specific pathological state. Corpora arenacea occur not only in the actual pineal tissue but also in the leptomeninges, in the habenular commissure and in the choroid plexus. Studies with the potassium pyroantimonate (PPA) method on the ultrastructural localization of free calcium ions in the human pineal, revealed the presence of calcium alongside the cell membranes, a finding that underlines the importance of membrane functions in the production of calcium deposits. Intrapineal corpora arenacea are characterized by a surface with globular structures. Meningeal acervuli that are present in the arachnoid cover of the organ, differ in structure from intrapineal ones and show a prominent concentric lamination of alternating dark and light lines. The electron-lucent lines contain more calcium than the dark ones. There is a correlation between the age of the subject and the number of layers in the largest acervuli. This suggests that the formation of these layers is connected to circannual changes in the calcium level of the organ. The histological organization of the human pineal is basically the same as that of mammalian experimental animals. Pineal concretions present in mammalian animal species are mainly of the meningeal type. Meningeal cells around acervuli contain active cytoplasmic organelles and exhibit alkaline phosphatase reaction in the rat and mink, an indication of a presumable

  3. Gastrointestinal stromal tumor presenting with prominent calcification

    PubMed Central

    Izawa, Naoki; Sawada, Takeshi; Abiko, Ryuichi; Kumon, Daisuke; Hirakawa, Mami; Kobayashi, Mika; Obinata, Nobuyuki; Nomoto, Masahito; Maehata, Tadateru; Yamauchi, Shun-ichi; Kouro, Takefumi; Tsuda, Takashi; Kitajima, Satoshi; Yasuda, Hiroshi; Tanaka, Keiichi; Tanaka, Ichiro; Hoshikawa, Masahiro; Takagi, Masayuki; Itoh, Fumio

    2012-01-01

    We present a rare case of a gastrointestinal stromal tumor (GIST) in the stomach with prominent calcification at presentation. A 61-year-old woman visited our hospital because of epigastric discomfort. A spherical calcified lesion with a diameter of about 30 mm was incidentally shown in the left upper quadrant on an abdominal X-ray. Computed tomography demonstrated that the tumor was growing from the upper gastric body, with calcification in the peripheral ring area. A laparoscopic partial gastrectomy was performed, and the resected specimen revealed a well-circumscribed tumor with exophytic growth from the gastric muscularis propria. Microscopic examination revealed spindle-shaped tumor cells with calcification and hemorrhage. Additionally, positive immunoreactivity of the tumor to KIT and CD34 and a low mitotic index resulted in the diagnosis of very low risk GIST. There are a few case reports of heavily calcified GIST, although solitary or punctate calcification of primary GIST has been reported in several case series. Dystrophic calcification of necrotic or degenerative tissue is the supposed cause of primary calcified GISTs. In contrast, appearance of calcification after administration of imatinib mesylate, which may be one indicator of disease response, is possibly caused by a different mechanism. PMID:23112561

  4. Influence of racket properties on injuries and performance in tennis.

    PubMed

    Hennig, Ewald M

    2007-04-01

    Racket properties may affect tennis elbow development. Shock and vibration to the arm is influenced by the location of ball impacts on the racket head, racket stiffness, and grip force. Beginners experience increased arm loads, and they hit the ball lower on the racket head. Tennis rackets behave differently during actual play compared with the performance predicted by physics.

  5. Lifetime, untreated isolated GH deficiency due to a GH-releasing hormone receptor mutation has beneficial consequences on bone status in older individuals, and does not influence their abdominal aorta calcification.

    PubMed

    Souza, Anita H O; Farias, Maria I T; Salvatori, Roberto; Silva, Gabriella M F; Santana, João A M; Pereira, Francisco A; de Paula, Francisco J A; Valença, Eugenia H O; Melo, Enaldo V; Barbosa, Rita A A; Pereira, Rossana M C; Gois-Junior, Miburge B; Aguiar-Oliveira, Manuel H

    2014-09-01

    The GH/IGF-I axis has essential roles in regulating bone and vascular status. The age-related decrease in GH secretion ("somatopause") may contribute to osteoporosis and atherosclerosis, commonly observed in the elderly. Adult-onset GH deficiency (GHD) has been reported to be associated with reduced bone mineral density (BMD), increased risk of fractures, and premature atherosclerosis. We have shown the young adult individuals with isolated GHD (IGHD) due to a homozygous for the c.57+1G>A GHRH receptor gene mutation have normal volumetric BMD (vBMD), and not develop premature atherosclerosis, despite adverse risk factor profile. However, the bone and vascular impact of lifetime GHD on the aging process remains unknown. We studied a group of ten older IGHD subjects (≥60 years) homozygous for the mutation, comparing them with 20 age- and gender-matched controls (CO). Areal BMD was measured, and vBMD was calculated at the lumbar spine and total hip. Vertebral fractures and abdominal aortic calcifications (expressed as calcium score) were also assessed. Areal BMD was lower in IGHD, but vBMD was similar in the two groups. The percent of fractured individuals was similar, but the mean number of fractures per individual was lower in IGHD than CO. Calcium score was similar in the two groups. A positive correlation was found between calcium score and number of fractures. Untreated lifetime IGHD has beneficial consequences on bone status and does not have a deleterious effect on abdominal aorta calcification. PMID:24272598

  6. Acute Renal Infarction Secondary to Calcific Embolus from Mitral Annular Calcification

    SciTech Connect

    Bande, Dinesh; Abbara, Suhny; Kalva, Sanjeeva P.

    2011-06-15

    We report a case of a 62-year-old man who presented with right groin pain who subsequently was found to have a renal infarct secondary to calcific embolus from mitral annular calcification on CT and angiography. We briefly review the literature and discuss the importance of this entity in clinical practice.

  7. Acute renal infarction secondary to calcific embolus from mitral annular calcification.

    PubMed

    Bande, Dinesh; Abbara, Suhny; Kalva, Sanjeeva P

    2011-06-01

    We report a case of a 62-year-old man who presented with right groin pain who subsequently was found to have a renal infarct secondary to calcific embolus from mitral annular calcification on CT and angiography. We briefly review the literature and discuss the importance of this entity in clinical practice.

  8. Tungsten nanoparticles influence on radiation protection properties of polymers

    NASA Astrophysics Data System (ADS)

    Gavrish, V. M.; Baranov, G. A.; Chayka, T. V.; Derbasova, N. M.; Lvov, A. V.; Matsuk, Y. M.

    2016-02-01

    In the presented article the results of the study of metal-polymer composites based on the ultra-high molecular weight polyethylene GUR 4122 with the addition of superdispersed tungsten nanopowders with 5, 10, 20, 40, and 50 mass percent content levels are given, their thermophysical, radiation-shielding, and mechanical properties are shown, and the influence of content levels of tungsten superdispersed nanopowders on these properties is analyzed. The conducted studies have shown the increase in the listed properties depending on the content level of tungsten superdispersed and nanopowders in the ultra-high molecular weight polyethylene GUR 4122. Owing to their properties, the obtained materials may be used in various fields, such as aviation, space technologies, mechanical engineering, etc.

  9. Microstructural influences on the mechanical properties of solder

    SciTech Connect

    Morris, J.W. Jr.; Goldstein, J.L.F.; Mei, Z.

    1993-04-01

    Intent of this book is to review analytic methods for predicting behavior of solder joints, based on continuum mechanics. The solder is treated as a continuous, homogeneous body, or composite of such bodies, whose mechanical behavior is uniform and governed by simple constitutive equations. The microstructure of a solder joint influences its mechanical properties in 3 ways: it governs deformation and failure; common solders deform inhomogeneously; and common solders are microstructurally unstable. The variety of microstructures often found in solder joints are briefly reviewed, and some of the ways are discussed in which the microstructure influences the common types of high-temperature mechanical behavior. 25 figs, 40 refs.

  10. Idiopathic Arterial Calcification of Infancy: Case Report.

    PubMed

    Attia, Tarek Hamed; Abd Alhamed, Mohamed Maisara; Selim, Mohamed Fouad; Haggag, Mohamed Salah; Fathalla, Diaa

    2015-11-01

    Idiopathic arterial calcification of infancy is a rare autosomal recessive disease, characterized by deposition of calcium along the internal elastic membrane of arteries, accompanied by fibrous thickening of the intima which causes luminal narrowing. Here we are reporting a case of idiopathic arterial calcification of infancy in a Saudi female newborn of non-consanguineous pregnant woman who had polyhydramnios. The newborn baby had severe respiratory distress, systemic hypertension and persistent pulmonary hypertension of newborn. She was admitted to Neonatal Intensive Care Unit, where she was ventilated and proper treatment was provided. Molecular genetic testing was positive for mutations of ectonucleotide pyrophosphatase/phosphodiesterase1 gene which is reported in 80% of cases of Idiopathic arterial calcification of infancy. The baby died at about 5 month of age because of myocardial ischemia and cardiorespiratory arrest. Idiopathic Arterial Calcification of Infancy should be considered in any newborn who presented with persistent pulmonary hypertension of newborn, severe systemic hypertension and echogenic vessels on any radiological study. Calcifications of large and medium-sized arteries are important diagnostic finding.

  11. Influence of Laser Reconditioning on Fatigue Properties of Crankshafts

    NASA Astrophysics Data System (ADS)

    Koehler, Henry; Partes, Knut; Seefeld, Thomas; Vollertsen, Frank

    Expensive machine parts often are repaired by additive processes to limit costs and increase productivity. However, repairing marine diesel engine crankshafts for these aims is not yet approved by the classification societies since the influence on mechanical properties can neither be predicted nor has been investigated sufficiently. A method for testing the influence of laser cladding on fatigue properties of marine crankshafts is presented. Tests on flat specimen indicated a drop in fatigue strength in consequence of laser cladding. The number of bearable load cycles of cladded crankshaft segments at 100% fatigue strength calculated according to CIMAC standards dropped. Origins of cracks could be traced back to cladded areas as well as to crankshaft fillets.

  12. Magnetic Interactions Influence the Properties of Helium Defects in Iron.

    SciTech Connect

    Seletskaia, Tatiana; Osetskiy, Yury N; Stoller, Roger E; Stocks, George Malcolm

    2005-01-01

    Density functional theory calculations of He defect properties in iron have shown an unexpected influence of magnetism arising from the defect's electronic structure. In contrast with previous work that neglected such effects, the results indicate that the tetrahedral position is energetically more favorable for the He interstitial than the octahedral site. This may have significant implications for He clustering and bubble nucleation, which will impact material performance in future fusion reactors. These results provide the basis for development of improved atomistic models.

  13. Foraminiferal calcification response to glacial-interglacial changes in atmospheric CO2.

    PubMed

    Barker, Stephen; Elderfield, Henry

    2002-08-01

    A record of foraminiferal shell weight across glacial-interglacial Termination I shows a response related to seawater carbonate ion concentration and allows reconstruction of a record of carbon dioxide in surface seawater that matches the atmospheric record. The results support suggestions that higher atmospheric carbon dioxide directly affects marine calcification, an effect that may be of global importance to past and future changes in atmospheric CO2. The process provides negative feedback to the influence of marine calcification on atmospheric carbon dioxide and is of practical importance to the application of paleoceanographic proxies.

  14. High-Dose Menaquinone-7 Supplementation Reduces Cardiovascular Calcification in a Murine Model of Extraosseous Calcification

    PubMed Central

    Scheiber, Daniel; Veulemans, Verena; Horn, Patrick; Chatrou, Martijn L.; Potthoff, Sebastian A.; Kelm, Malte; Schurgers, Leon J.; Westenfeld, Ralf

    2015-01-01

    Cardiovascular calcification is prevalent in the aging population and in patients with chronic kidney disease (CKD) and diabetes mellitus, giving rise to substantial morbidity and mortality. Vitamin K-dependent matrix Gla-protein (MGP) is an important inhibitor of calcification. The aim of this study was to evaluate the impact of high-dose menaquinone-7 (MK-7) supplementation (100 µg/g diet) on the development of extraosseous calcification in a murine model. Calcification was induced by 5/6 nephrectomy combined with high phosphate diet in rats. Sham operated animals served as controls. Animals received high or low MK-7 diets for 12 weeks. We assessed vital parameters, serum chemistry, creatinine clearance, and cardiac function. CKD provoked increased aortic (1.3 fold; p < 0.05) and myocardial (2.4 fold; p < 0.05) calcification in line with increased alkaline phosphatase levels (2.2 fold; p < 0.01). MK-7 supplementation inhibited cardiovascular calcification and decreased aortic alkaline phosphatase tissue concentrations. Furthermore, MK-7 supplementation increased aortic MGP messenger ribonucleic acid (mRNA) expression (10-fold; p < 0.05). CKD-induced arterial hypertension with secondary myocardial hypertrophy and increased elastic fiber breaking points in the arterial tunica media did not change with MK-7 supplementation. Our results show that high-dose MK-7 supplementation inhibits the development of cardiovascular calcification. The protective effect of MK-7 may be related to the inhibition of secondary mineralization of damaged vascular structures. PMID:26295257

  15. High-Dose Menaquinone-7 Supplementation Reduces Cardiovascular Calcification in a Murine Model of Extraosseous Calcification.

    PubMed

    Scheiber, Daniel; Veulemans, Verena; Horn, Patrick; Chatrou, Martijn L; Potthoff, Sebastian A; Kelm, Malte; Schurgers, Leon J; Westenfeld, Ralf

    2015-08-01

    Cardiovascular calcification is prevalent in the aging population and in patients with chronic kidney disease (CKD) and diabetes mellitus, giving rise to substantial morbidity and mortality. Vitamin K-dependent matrix Gla-protein (MGP) is an important inhibitor of calcification. The aim of this study was to evaluate the impact of high-dose menaquinone-7 (MK-7) supplementation (100 µg/g diet) on the development of extraosseous calcification in a murine model. Calcification was induced by 5/6 nephrectomy combined with high phosphate diet in rats. Sham operated animals served as controls. Animals received high or low MK-7 diets for 12 weeks. We assessed vital parameters, serum chemistry, creatinine clearance, and cardiac function. CKD provoked increased aortic (1.3 fold; p < 0.05) and myocardial (2.4 fold; p < 0.05) calcification in line with increased alkaline phosphatase levels (2.2 fold; p < 0.01). MK-7 supplementation inhibited cardiovascular calcification and decreased aortic alkaline phosphatase tissue concentrations. Furthermore, MK-7 supplementation increased aortic MGP messenger ribonucleic acid (mRNA) expression (10-fold; p < 0.05). CKD-induced arterial hypertension with secondary myocardial hypertrophy and increased elastic fiber breaking points in the arterial tunica media did not change with MK-7 supplementation. Our results show that high-dose MK-7 supplementation inhibits the development of cardiovascular calcification. The protective effect of MK-7 may be related to the inhibition of secondary mineralization of damaged vascular structures. PMID:26295257

  16. Dark calcification and the daily rhythm of calcification in the scleractinian coral, Galaxea fascicularis

    NASA Astrophysics Data System (ADS)

    Al-Horani, F. A.; Tambutté, É.; Allemand, D.

    2007-09-01

    The rate of calcification in the scleractinian coral Galaxea fascicularis was followed during the daytime using 45Ca tracer. The coral began the day with a low calcification rate, which increased over time to a maximum in the afternoon. Since the experiments were carried out under a fixed light intensity, these results suggest that an intrinsic rhythm exists in the coral such that the calcification rate is regulated during the daytime. When corals were incubated for an extended period in the dark, the calcification rate was constant for the first 4 h of incubation and then declined, until after one day of dark incubation, calcification ceased, possibly as a result of the depletion of coral energy reserves. The addition of glucose and Artemia reduced the dark calcification rate for the short duration of the experiment, indicating an expenditure of oxygen in respiration. Artificial hypoxia reduced the rate of dark calcification to about 25% compared to aerated coral samples. It is suggested that G. fascicularis obtains its oxygen needs from the surrounding seawater during the nighttime, whereas during the day time the coral exports oxygen to the seawater.

  17. Regulatory Circuits Controlling Vascular Cell Calcification

    PubMed Central

    Sallam, Tamer; Cheng, Henry; Demer, Linda L.; Tintut, Yin

    2013-01-01

    Vascular calcification is a common feature of chronic kidney disease, cardiovascular disease, and aging. Such abnormal calcium deposition occurs in medial and/or intimal layers of blood vessels as well as in cardiac valves. Once considered a passive and inconsequential finding, the presence of calcium deposits in the vasculature is widely accepted as a predictor of increased morbidity and mortality. Recognition of the importance of vascular calcification in health is driving research into mechanisms that govern its development, progression, and regression. Diverse, but highly interconnected factors, have been implicated, including disturbances in lipid metabolism, oxidative stress, inflammatory cytokines, and mineral and hormonal balances, which can lead to formation of osteoblast-like cells in the artery wall. A tight balance of procalcific and anticalcific regulators dictates the extent of disease. In this review, we focus on the main regulatory circuits modulating vascular cell calcification. PMID:23269436

  18. Calcific band keratopathy in an alpaca.

    PubMed

    Pucket, Jonathan D; Boileau, Melanie J; Sula, Mee Ja M

    2014-07-01

    A 4-year-old female Suri alpaca was presented for evaluation of acute onset weakness, lethargy, and recent development of opacities in both eyes. On ophthalmic examination, bilaterally symmetrical corneal opacities were noted along the interpalpebral fissures with a few corneal blood vessels intermingled. A presumed diagnosis of calcific band keratopathy was made based on location and appearance. The patient was euthanized a short while after diagnosis due to reasons unrelated to the eyes and histologic examination of the corneas revealed subepithelial calcium and vascularization, consistent with calcific band keratopathy. This case report is the first to document this ocular condition in an alpaca.

  19. Dystrophic calcification of the prostate after cryotherapy.

    PubMed

    Dru, Christopher; Bender, Leon

    2014-01-01

    We present a previously undocumented complication of dystrophic calcification of the prostate after cryotherapy. An 87-year-old male presented with recurrent lower urinary tract infections and was found to have an obstructing large calcified mass in the right lobe of the prostate. Subsequently, he underwent transurethral resection of the prostate (TURP) and bladder neck with laser lithotripsy to remove the calculus. We propose that chronic inflammation and necrosis of the prostate from cryotherapy resulted in dystrophic calcification of the prostate. As the use of cryotherapy for the treatment of localized prostate cancer continues to increase, it is important that clinicians be aware of this scenario and the technical challenges it poses.

  20. Effect of manganese on calcification of bone

    PubMed Central

    Tal, E.; Guggenheim, K.

    1965-01-01

    1. Young mice were maintained on a basal diet composed of meat, which is poor in both manganese and calcium. 2. The addition of small amounts (2·5–5·0mg./kg. of meat) of manganese improved weight gain and calcification of bone and decreased incorporation of injected radiocalcium into bone. 3. Prolonged treatment with larger amounts (10·0–25·0mg./kg. of meat) of manganese depressed growth, induced defective calcification of bone and increased incorporation of radiocalcium into bone. PMID:14333572

  1. An investigation of aerosol optical properties: Atmospheric implications and influences

    NASA Astrophysics Data System (ADS)

    Penaloza-Murillo, Marcos A.

    An experimental, observational, and theoretical investigation of aerosol optical properties has been made in this work to study their implications and influences on the atmosphere. In the laboratory the scientific and instrumental methodology consisted of three parts, namely, aerosol generation, optical and mass concentration measurements, and computational calculations. In particular the optical properties of ammonium sulfate and caffeine aerosol were derived from measurements made with a transmissometer cell-reciprocal- integrating nephelometer (TCRIN), equipped with a laser beam at 632.8 nm, and by applying a Mie theory computer code The aerosol generators, optical equipment and calibration procedures were reviewed. The aerosol shape and size distribution were studied by means of scanning electron microscopy and the Gumprecht- Sliepcevich/Lipofsky-Green extinction-sedimentation method. In particular the spherical and cylindrical shape were considered. During this investigation, an alternative method for obtaining the optical properties of monodisperse spherical non-absorbing aerosol using a cell-transmissometer, which is based on a linearisation of the Lambert-Beer law, was found. In addition, adapting the TCRIN to electrooptical aerosol studies, the optical properties of a circular-cylindrical aerosol of caffeine were undertaken under the condition of random orientation in relation with the laser beam, and perpendicular orientation to it. A theoretical study was conducted to assess the sensitivity of aerosol to a change of shape under different polarisation modes. The aerosol optical properties, obtained previously in the laboratory, were then used to simulate the direct radiative forcing. The calculations and results were obtained by applying a one- dimensional energy-balance box model. The influence of atmospheric aerosol on the sky brightness due to a total solar eclipse was studied using the photometric and meteorological observations made during the

  2. Influence of Delhi Pollution on Aerosol Properties Over Greater Noida

    NASA Astrophysics Data System (ADS)

    Sharma, M.; Singh, R. P.; Kumar, R.

    2015-12-01

    Influence of Delhi Pollution on Aerosol Properties over Greater NoidaManish Sharma1, Ramesh P. Singh2 and Rajesh Kumar3 1Research and Technology Development Centre, Sharda University, Greater Noida, India. 2School of Earth and Environmental Sciences, Schmid College of Science, Chapman University, Orange 92866, USA 3School of Basic Sciences and Research, Sharda University, Greater Noida, India. Delhi capital of India is highly polluted during winter and summer seasons. Due to dominant westerly winds the air mass influence its neighboring city Greater Noida which is located 60 km south east of Delhi. Detailed analysis of multi satellite data and ground observations have been carried out during 2001-2015. The ground observation and satellite data show dynamic aerosol optical parameters over Greater Noida. During winter and summer seasons, dominant westerly wind outflow pollutants of Delhi that mix with the local anthropogenic emissions of Greater Noida influencing aerosol properties at different pressure levels. The characteristics of trace gases and aerosol parameters over Delhi and Greater Noida will be presented. The air quality is severely affected from the outflow of pollutants from Delhi which is threat to people living in the area. Due to dominant winds the air mass further transported towards eastern parts of Indo-Gangetic plains affecting weather conditions of the major cities.

  3. Linking calcification by exotic snails to stream inorganic carbon cycling.

    PubMed

    Hotchkiss, Erin R; Hall, Robert O

    2010-05-01

    Biotic calcification is rarely considered in freshwater C budgets, despite calculations suggesting that calcifying animals can alter inorganic C cycling. Most studies that have quantified biocalcification in aquatic ecosystems have not directly linked CO(2) fluxes from biocalcification with whole-ecosystem rates of inorganic C cycling. The freshwater snail, Melanoides tuberculata, has achieved a high abundance and 37.4 g biomass m(-2) after invading Kelly Warm Springs in Grand Teton National Park. This high biomass suggests that introduced populations of Melanoides may alter ecosystem processes. We measured Melanoides growth rates and biomass to calculate the production of biomass, shell mass, and CO(2). We compared Melanoides biomass and inorganic C production with ecosystem C pools and fluxes, as well as with published rates of CO(2) production by other calcifying organisms. Melanoides calcification in Kelly Warm Springs produced 12.1 mmol CO(2) m(-2) day(-1) during summer months. We measured high rates of gross primary productivity and respiration in Kelly Warm Springs (-378 and 533 mmol CO(2) m(-2) day(-1), respectively); CO(2) produced from biocalcification increased net CO(2) production in Kelly Warm Springs from 155 to 167 mmol CO(2) m(-2) day(-1). This rate of CO(2) production via biocalcification is within the published range of calcification by animals. But these CO(2) fluxes are small when compared to ecosystem C fluxes from stream metabolism. The influence of animals is relative to ecosystem processes, and should always be compared with ecosystem fluxes to quantify the importance of a specific animal in its environment.

  4. Scattering properties of a composite resin: Influence on color perception

    PubMed Central

    Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Bianchi, Stefano; Poggio, Claudio

    2014-01-01

    Background: The properties of the composite materials and the clinical expertise while layering them carry many esthetic implications in restorative dentistry. Aims: The aim of the present study is to assess the influence of scattering properties of G-aenial A2 shade on color perception when used in esthetic restorations. Materials and Methods: Two composite resins were evaluated in this study: Gradia Direct (shade A3) and G-aenial (shade A2). A colorimetric evaluation according to the CIE L*a*b* system, relative to standard illuminant A against a white background, was performed to assess the referred chameleonic properties of G-aenial when used in simulated clinical situations. Statistical Analysis Used: The differences in color change between the test group G-aenial and the test Group Gradia Direct were considered clinically not perceptible (ΔE* <3.3). Differently, the differences in color change were considered clinically perceptible (ΔE* >3.3) between the control group G-aenial and the control group Gradia Direct and between the test group G-aenial and the control specimens obtained with G-aenial. The CIE Lab parameters which brought to ΔE were investigated using t-test (P < 0.05). Results and Conclusions: Color harmonization in simulated clinical conditions depends on different factors related to dentine and to composite resins. In this study dentine variables were dropped in order to analyze the influence of thickness and of the composition of the composite resin. PMID:25395767

  5. Association of mitral annulus calcification, aortic valve calcification with carotid intima media thickness

    PubMed Central

    Sgorbini, Luca; Scuteri, Angelo; Leggio, Massimo; Leggio, Francesco

    2004-01-01

    Background Mitral annular calcification (MAC) and aortic annular calcification (AVC) may represent a manifestation of generalized atherosclerosis in the elederly. Alterations in vascular structure, as indexed by the intima media thickness (IMT), are also recognized as independent predictors of adverse cardiovascular outcomes. Aim To examine the relationship between the degree of calcification at mitral and/or aortic valve annulus and large artery structure (thickness). Methods We evaluated 102 consecutive patients who underwent transthoracic echocardiography and carotid artery echoDoppler for various indications; variables measured were: systemic blood pressure (BP), pulse pressure (PP=SBP-DBP), body mass index (BMI), fasting glucose, total, HDL, LDL chlolesterol, triglycerides, cIMT. The patients were divided according to a grading of valvular/annular lesions independent scores based on acoustic densitometry: 1 = annular/valvular sclerosis/calcification absence; 2 = annular/valvular sclerosis; 3 = annular calcification; 4 = annular-valvular calcification; 5 = valvular calcification with no recognition of the leaflets. Results Patient score was the highest observed for either valvular/annulus. Mean cIMT increased linearly with increasing valvular calcification score, ranging from 3.9 ± 0.48 mm in controls to 12.9 ± 1.8 mm in those subjects scored 5 (p < 0.0001). In the first to fourth quartile of cIMT values the respective maximal percentual of score were: score 1: 76.1%, score 2: 70.1%, score 4: 54.3% and score 5: 69.5% (p > 0.0001). Conclusion MAC and AVC score can identify subgroups of patients with different cIMT values which indicate different incidence and prevalence of systemic artery diseases. This data may confirm MAC-AVC as a useful important diagnostic parameter of systemic atherosclerotic disease. PMID:15471552

  6. Aneurysm strength can decrease under calcification.

    PubMed

    Volokh, Konstantin Y; Aboudi, Jacob

    2016-04-01

    Aneurysms are abnormal dilatations of vessels in the vascular system that are prone to rupture. Prediction of the aneurysm rupture is a challenging and unsolved problem. Various factors can lead to the aneurysm rupture and, in the present study, we examine the effect of calcification on the aneurysm strength by using micromechanical modeling. The calcified tissue is considered as a composite material in which hard calcium particles are embedded in a hyperelastic soft matrix. Three experimentally calibrated constitutive models incorporating a failure description are used for the matrix representation. Two constitutive models describe the aneurysmal arterial wall and the third one - the intraluminal thrombus. The stiffness and strength of the calcified tissue are simulated in uniaxial tension under the varying amount of calcification, i.e. the relative volume of the hard inclusion within the periodic unit cell. In addition, the triaxiality of the stress state, which can be a trigger for the cavitation instability, is tracked. Results of the micromechanical simulation show an increase of the stiffness and a possible decrease of the strength of the calcified tissue as compared to the non-calcified one. The obtained results suggest that calcification (i.e. the presence of hard particles) can significantly affect the stiffness and strength of soft tissue. The development of refined experimental techniques that will allow for the accurate quantitative assessment of calcification is desirable. PMID:26717251

  7. The Influence of Fuelbed Physical Properties on Biomass Burning Emissions

    NASA Astrophysics Data System (ADS)

    Urbanski, S. P.; Lincoln, E.; Baker, S. P.; Richardson, M.

    2014-12-01

    Emissions from biomass fires can significantly degrade regional air quality and therefore are of major concern to air regulators and land managers in the U.S. and Canada. Accurately estimating emissions from different fire types in various ecosystems is crucial to predicting and mitigating the impact of fires on air quality. The physical properties of ecosystems' fuelbeds can heavily influence the combustion processes (e.g. flaming or smoldering) and the resultant emissions. However, despite recent progress in characterizing the composition of biomass smoke, significant knowledge gaps remain regarding the linkage between basic fuelbed physical properties and emissions. In laboratory experiments we examined the effects of fuelbed properties on combustion efficiency (CE) and emissions for an important fuel component of temperate and boreal forests - conifer needles. The bulk density (BD), depth (DZ), and moisture content (MC) of Ponderosa Pine needle fuelbeds were manipulated in 75 burns for which gas and particle emissions were measured. We found CE was negatively correlated with BD, DZ and MC and that the emission factors of species associated with smoldering combustion processes (CO, CH4, particles) were positively correlated with these fuelbed properties. The study indicates the physical properties of conifer needle fuelbeds have a significant effect on CE and hence emissions. However, many of the emission models used to predict and manage smoke impacts on air quality assume conifer litter burns by flaming combustion with a high CE and correspondingly low emissions of CO, CH4, particles, and organic compounds. Our results suggest emission models underestimate emissions from fires involving a large component of conifer needles. Additionally, our findings indicate that laboratory studies of emissions should carefully control fuelbed physical properties to avoid confounding effects that may obscure the effects being tested and lead to erroneous interpretations.

  8. Characteristics of rib cartilage calcification in Asian patients.

    PubMed

    Sunwoo, Woong Sang; Choi, Hyo Geun; Kim, Dae Woo; Jin, Hong-Ryul

    2014-01-01

    IMPORTANCE Rib cartilage from the sixth, seventh, and eighth ribs offers a long cartilaginous curvature, making the material reliable for grafting. Calcification of cartilage causes unexpected absorption, difficult manipulation, and donor site morbidity. Most studies of calcification were performed in Western countries. OBJECTIVE To investigate the incidence, degree, and pattern of rib cartilage calcification in Asian patients. DESIGN, SETTING, AND PARTICIPANTS Retrospective study of computed tomographic scans of the chest in 120 patients (60 male and 60 female). The incidence, degree, and pattern of cartilage calcification of the sixth through eighth ribs were noted. The patients were stratified into 6 age groups, and 20 patients (10 male and 10 female) were selected for each group. The degree of calcification was assessed as 0%, 1% to 25%, 26% to 50%, 51% to 75%, and 76% to 100%. Meaningful calcification was defined as 26% or greater. The pattern of calcification was classified as marginal, granular, and central. EXPOSURE Computed tomographic scans of the chest. MAIN OUTCOMES AND MEASURES Degree of calcification, presence of meaningful calcification, and calcification pattern. RESULTS Overall, 50.8% of cartilage was calcified, and female patients showed more frequent calcification than male patients (59.4% vs 42.2% [P < .001]). Calcification rates of the sixth and seventh rib cartilage were higher than those of the eighth rib cartilage in all age groups except teenagers, who had a similar rate for all 3 ribs. Calcification of the sixth and seventh rib cartilage significantly increased with age. A meaningful calcification rate was very low in males younger than 60 years, whereas the rate was relatively higher in females than males for all age groups. Males predominantly had the marginal type of calcification, whereas females predominantly had a granular type. The rate and pattern of calcification had no relationship to age. CONCLUSIONS AND RELEVANCE In Asian

  9. Osteoporosis and vascular calcification in postmenopausal women: a cross-sectional study.

    PubMed

    Lampropoulos, C E; Kalamara, P; Konsta, M; Papaioannou, I; Papadima, E; Antoniou, Z; Andrianopoulou, A; Vlachoyiannopoulos, P G

    2016-06-01

    Objectives To estimate the correlation between osteoporosis and vascular calcification in postmenopausal women and the influence of calcium/vitamin D supplements on vascular calcification. Methods A cross-sectional study was performed including 29 women with osteoporosis (15 not taking supplements) and 18 age-matched, non-osteoporotic women. They were evaluated for cardiovascular risk factors and blood tests, lateral X-ray of lumbar spine (assessment of abdominal aorta calcification, AAC) and carotid ultrasound (increased intima media thickness (iIMT) or calcified plaques) were performed. Results In univariate analysis, osteoporotic women were 16 times more likely to develop AAC (odds ratio (OR) 15.8, 95% confidence interval (CI) 1.9-135.4) and seven times more likely to develop iIMT (OR 6.8, 95% CI 1.8-25.4) compared to normal individuals. The odds of developing AAC and iIMT were increased each year after menopause (OR 1.11, 95% CI 1.01-1.2 and OR 1.18, 95% CI 1.05-1.3, respectively) and with aging (OR 1.27, 95% CI 1.1-1.47 and OR = 1.17, 95% CI 1.04-1.3, respectively). Calcified plaques were significantly correlated with osteoporosis (p = 0.014). In multivariate analysis, osteoporosis was an independent risk factor for AAC (OR 13.3, 95% CI 1.3-134.4) and iIMT (OR 4.7, 95% CI 1.1-19.9). Low doses of supplements did not appear to affect vascular calcification (p = 0.6). Conclusions Osteoporosis is associated with increased calcification of the abdominal aorta and carotids. Low doses of supplements do not appear to cause any increase in vascular calcification in osteoporotic women. PMID:27045323

  10. Influence of the Soil Genesis on Physical and Mechanical Properties

    PubMed Central

    Marschalko, Marian; Yilmaz, Işık; Fojtová, Lucie; Kubečka, Karel; Bouchal, Tomáš; Bednárik, Martin

    2013-01-01

    The paper deals with the influence of soil genesis on the physical-mechanical properties. The presented case study was conducted in the region of the Ostrava Basin where there is a varied genetic composition of the Quaternary geological structure on the underlying Neogeneous sediments which are sediments of analogous granulometry but different genesis. In this study, 7827 soil samples of an eolian, fluvial, glacial, and deluvial origin and their laboratory analyses results were used. The study identified different values in certain cases, mostly in coarser-grained foundation soils, such as sandy loam S4 (MS) and clayey sand F4 (CS). The soils of the fluvial origin manifest different values than other genetic types. Next, based on regression analyses, dependence was proved neither on the deposition depth (depth of samples) nor from the point of view of the individual foundation soil classes or the genetic types. The contribution of the paper is to point at the influence of genesis on the foundation soil properties so that engineering geologists and geotechnicians pay more attention to the genesis during engineering-geological and geotechnical investigations. PMID:23844398

  11. Influence of the soil genesis on physical and mechanical properties.

    PubMed

    Marschalko, Marian; Yilmaz, Işık; Fojtová, Lucie; Kubečka, Karel; Bouchal, Tomáš; Bednárik, Martin

    2013-01-01

    The paper deals with the influence of soil genesis on the physical-mechanical properties. The presented case study was conducted in the region of the Ostrava Basin where there is a varied genetic composition of the Quaternary geological structure on the underlying Neogeneous sediments which are sediments of analogous granulometry but different genesis. In this study, 7827 soil samples of an eolian, fluvial, glacial, and deluvial origin and their laboratory analyses results were used. The study identified different values in certain cases, mostly in coarser-grained foundation soils, such as sandy loam S4 (MS) and clayey sand F4 (CS). The soils of the fluvial origin manifest different values than other genetic types. Next, based on regression analyses, dependence was proved neither on the deposition depth (depth of samples) nor from the point of view of the individual foundation soil classes or the genetic types. The contribution of the paper is to point at the influence of genesis on the foundation soil properties so that engineering geologists and geotechnicians pay more attention to the genesis during engineering-geological and geotechnical investigations.

  12. Acute Calcific Bursitis After Ultrasound-Guided Percutaneous Barbotage of Rotator Cuff Calcific Tendinopathy: A Case Report.

    PubMed

    Kang, Bo-Sung; Lee, Seung Hak; Cho, Yung; Chung, Sun Gun

    2016-08-01

    Ultrasound-guided percutaneous barbotage is an effective treatment for rotator cuff calcific tendinopathy, providing rapid and substantial pain relief. We present the case of a 49-year-old woman with aggravated pain early after ultrasound-guided barbotage of a large calcific deposit in the supraspinatus tendon. Subsequent examination revealed a thick calcification spreading along the subacromial-subdeltoid bursa space, suggesting acute calcific bursitis complicated by barbotage. Additional barbotage alleviated her pain completely. Therefore, a high index of suspicion for acute calcific bursitis is required in patients with unresolved or aggravated pain after barbotage. Repeated barbotage could be effective for this condition. PMID:26902864

  13. Adipocyte induced arterial calcification is prevented with sodium thiosulfate

    SciTech Connect

    Chen, Neal X.; O’Neill, Kalisha; Akl, Nader Kassis; Moe, Sharon M.

    2014-06-20

    Highlights: • High phosphorus can induce calcification of adipocytes, even when fully differentiated. • Adipocytes can induce vascular calcification in an autocrine manner. • Sodium thiosulfate inhibits adipocyte calcification. - Abstract: Background: Calcification can occur in fat in multiple clinical conditions including in the dermis, breasts and in the abdomen in calciphylaxis. All of these are more common in patients with advanced kidney disease. Clinically, hyperphosphatemia and obesity are risk factors. Thus we tested the hypothesis that adipocytes can calcify in the presence of elevated phosphorus and/or that adipocytes exposed to phosphorus can induce vascular smooth muscle cell (VSMC) calcification. Methods: 3T3-L1 preadipocytes were induced into mature adipocytes and then treated with media containing high phosphorus. Calcification was assessed biochemically and PCR performed to determine the expression of genes for osteoblast and adipocyte differentiation. Adipocytes were also co-cultured with bovine VSMC to determine paracrine effects, and the efficacy of sodium thiosulfate was determined. Results: The results demonstrated that high phosphorus induced the calcification of differentiated adipocytes with increased expression of osteopontin, the osteoblast transcription factor Runx2 and decreased expression of adipocyte transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT-enhancer-binding protein α (CEBPα), indicating that high phosphorus led to a phenotypic switch of adipocytes to an osteoblast like phenotype. Sodium thiosulfate, dose dependently decreased adipocyte calcification and inhibited adipocyte induced increase of VSMC calcification. Co-culture studies demonstrated that adipocytes facilitated VSMC calcification partially mediated by changes of secretion of leptin and vascular endothelial growth factor (VEGF) from adipocytes. Conclusion: High phosphorus induced calcification of mature adipocytes, and

  14. Apparent Optical Properties in Waters Influenced by the Mississippi River

    NASA Technical Reports Server (NTRS)

    D'Sa, E.; Miller, R. L.; McKee, B. A.; Trzaska, R.

    2002-01-01

    In-water downwelling irradiance (E(sub d)) and upwelling radiance (L(sub u)) were measured in coastal waters influenced by the Mississippi River at wavelengths corresponding to SeaWiFS spectral bands in April of 2000. Results of derived apparent optical properties (AOP's) such as spectral diffise attenuation coefficient for downwelling irradiance (K(sub d)) suggest that they are mainly influenced by phytoplankton chlorophyll. Large variations in chlorophyll concentrations (0.2 to greater than 10 mg per cubic meters) correspond to variations in K(sub d) at 443 nm ranging from about 0.1 to greater than 1.5 per meter. Attenuation values at 443 nm generally peaked (or were minimal at 555 nm) at depths where chlorophyll concentrations were high. Above water remote sensing reflectance R(sub rs) (443) derived from E(sub d) and L(sub u) shows good agreement to surface chlorophyll. Ratios of remote sensing reflectance, R(sub rs)(443/R(sub rs)(555)versus chlorophyll suggests a potential for obtaining a suitable bio-optical algorithm for the region influenced by the Mississippi River.

  15. Factors That Influence the Extensional Rheological Property of Saliva.

    PubMed

    Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy

    2015-01-01

    The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva. PMID:26305698

  16. Factors That Influence the Extensional Rheological Property of Saliva

    PubMed Central

    Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy

    2015-01-01

    The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva. PMID:26305698

  17. Factors That Influence the Extensional Rheological Property of Saliva.

    PubMed

    Vijay, Amrita; Inui, Taichi; Dodds, Michael; Proctor, Gordon; Carpenter, Guy

    2015-01-01

    The spinnbarkeit of saliva reflects the ability of saliva to adhere to surfaces within the mouth, thereby serving as a protective role and aiding in lubrication. Therefore, alterations in the extensional rheology of saliva may result in the loss in adhesiveness or the ability to bind onto surfaces. Mucin glycoproteins and their structures are known to be important factors for the extensional rheological properties of saliva. The conformation of mucin depends on factors such as pH and ionic strength. Chewing is one of the main stimuli for salivary secretion but creates significant sheer stress on the salivary film which could influence mouthfeel perceptions. The current study investigates the possible factors which affect the extensional rheological properties of saliva by comparing submandibular/sublingual saliva with different oral stimuli within the same group of subjects. Unstimulated and stimulated saliva (chew, smell and taste) salivas were collected primarily from submandibular/sublingual glands. The saliva samples were measured for Spinnbarkeit followed by the measuring mucin, total protein, total calcium and bicarbonate concentrations. The results indicated correlations between rheological properties and mucin/ion concentrations. However, chewing stimulated submandibular/sublingual saliva is shown to have significantly lower Spinnbarkeit, but factors such as mucin, protein and calcium concentrations did not account for this variation. Analysis of the concentration of bicarbonate and pH appears to suggest that it has a prominent effect on extensional rheology of saliva.

  18. Influence of mechanical properties on the combustion of propellants

    NASA Technical Reports Server (NTRS)

    Kumar, R. N.; Culick, F. E. C.

    1973-01-01

    Experimental study of the effects of minor compositional variables upon the combustion behavior of composite solid propellants. More specifically, it was attempted to determine the influence of ingredients that improve the mechanical properties upon the oscillatory combustion characteristics. Tests were carried out in the familiar Crawford bomb, a low-pressure L-star burner, and a high-pressure T-burner. Two families of propellants were investigated; each family consists of two propellants with a minor compositional variation between them. In the family that shows a decreasing (steady state) pressure index (n) with increasing pressures, all of the combustion characteristics are found to be very similar although the mechanical properties are widely different. In the other family, which shows an increasing n with increasing pressures, unmistakable differences are found between the two propellants in the low-pressure L-star instability behavior (along with the differences in the mechanical properties), while the other combustion characteristics are almost identical. The results are interpreted to be consistent with a theory that highlights the importance of condensed phase heat-transfer effects.

  19. Gamma irradiation influence on physical properties of milk proteins

    NASA Astrophysics Data System (ADS)

    Cieśla, K.; Salmieri, S.; Lacroix, M.; Tien, C. Le

    2004-09-01

    Gamma irradiation was found to be an effective method for the improvement of both barrier and mechanical properties of the edible films and coatings based on calcium and sodium caseinates alone or combined with some globular proteins. Our current studies concern gamma irradiation influence on the physical properties of calcium caseinate-whey protein isolate-glycerol (1:1:1) solutions and gels, used for films preparation. Irradiation of solutions was carried out with Co-60 gamma rays applying 0 and 32 kGy dose. The increase in viscosity of solutions was found after irradiation connected to induced crosslinking. Lower viscosity values were detected, however, after heating of the solutions irradiated with a 32 kGy dose than after heating of the non-irradiated ones regarding differences in the structure of gels and resulting in different temperature-viscosity curves that were recorded for the irradiated and the non-irradiated samples during heating and cooling. Creation of less stiff but better ordered gels after irradiation arises probably from reorganisation of aperiodic helical phase and β-sheets, in particular from increase of β-strands, detected by FTIR. Films obtained from these gels are characterised by improved barrier properties and mechanical resistance and are more rigid than those prepared from the non-irradiated gels. The route of gel creation was investigated for the control and the irradiated samples during heating and the subsequent cooling.

  20. Calcification by Reef-Building Sclerobionts

    PubMed Central

    Mallela, Jennie

    2013-01-01

    It is widely accepted that deteriorating water quality associated with increased sediment stress has reduced calcification rates on coral reefs. However, there is limited information regarding the growth and development of reef building organisms, aside from the corals themselves. This study investigated encruster calcification on five fore-reefs in Tobago subjected to a range of sedimentation rates (1.2 to 15.9 mg cm−2 d−1). Experimental substrates were used to assess rates of calcification in sclerobionts (e.g. crustose coralline algae, bryozoans and barnacles) across key reef microhabitats: cryptic (low-light), exposed (open-horizontal) and vertical topographic settings. Sedimentation negatively impacted calcification by photosynthesising crustose coralline algae in exposed microhabitats and encrusting foram cover (%) in exposed and cryptic substrates. Heterotrophs were not affected by sedimentation. Fore-reef, turbid water encruster assemblages calcified at a mean rate of 757 (SD ±317) g m−2 y−1. Different microhabitats were characterised by distinct calcareous encruster assemblages with different rates of calcification. Taxa with rapid lateral growth dominated areal cover but were not responsible for the majority of CaCO3 production. Cryptobiont assemblages were composed of a suite of calcifying taxa which included sciaphilic cheilostome bryozoans and suspension feeding barnacles. These calcified at mean rates of 20.1 (SD ±27) and 4.0 (SD ±3.6) g m−2 y−1 respectively. Encruster cover (%) on exposed and vertical substrates was dominated by crustose coralline algae which calcified at rates of 105.3 (SD ±67.7) g m−2 y−1 and 56.3 (SD ±8.3) g m−2 y−1 respectively. Globally, encrusting organisms contribute significant amounts of carbonate to the reef framework. These results provide experimental evidence that calcification rates, and the importance of different encrusting organisms, vary significantly according to topography and sediment

  1. The influence of meteoric smoke particles on stratospheric aerosol properties

    NASA Astrophysics Data System (ADS)

    Mann, Graham; Brooke, James; Dhomse, Sandip; Plane, John; Feng, Wuhu; Neely, Ryan; Bardeen, Chuck; Bellouin, Nicolas; Dalvi, Mohit; Johnson, Colin; Abraham, Luke

    2016-04-01

    The ablation of metors in the thermosphere and mesosphere introduces a signficant source of particulate matter into the polar upper stratosphere. These meteoric smoke particles (MSP) initially form at nanometre sizes but in the stratosphere have grown to larger sizes (tens of nanometres) following coagulation. The presence of these smoke particles may represent a significant mechanism for the nucleation of polar stratospheric clouds and are also known to influence the properties of the stratospheric aerosol or Junge layer. In this presentation we present findings from experiments to investigate the influence of the MSP on the Junge layer, carried out with the UM-UKCA composition-climate model. The UM-UKCA model is a high-top (up to 80km) version of the general circulation model with well-resolved stratospheric dynamics, includes the aerosol microphysics module GLOMAP and has interactive sulphur chemistry suitable for the stratosphere and troposphere (Dhomse et al., 2014). We have recently added to UM-UKCA a source of meteoric smoke particles, based on prescribing the variation of the smoke particles from previous simulations with the Whole Atmosphere Community Climate Model (WACCM). In UM-UKCA, the MSP particles are transported within the GLOMAP aerosol framework, alongside interactive stratospheric sulphuric acid aerosol. For the experiments presented here, we have activated the interaction between the MSP and the stratospheric sulphuric acid aerosol. The MSP provide an important sink term for the gas phase sulphuric acid simulated in the model, with subsequent effects on the formation, growth and temporal evolution of stratospheric sulphuric acid aerosol particles. By comparing simulations with and without the MSP-sulphur interactions we quantify the influence of the meteoric smoke on the properties of volcanically-quiescent Junge layer. We also investigate the extent to which the MSP may modulate the effects from SO2 injected into the stratosphere from volcanic

  2. Localised pulmonary metastatic calcification associated with pulmonary artery obstruction.

    PubMed Central

    Bloodworth, J; Tomashefski, J F

    1992-01-01

    BACKGROUND: Metastatic pulmonary calcification, a complication of uraemia and disordered calcium metabolism, may be diffuse or localised. The factors that determine calcium precipitation are complex, but tissue alkalosis is thought to be important. As obstruction of the pulmonary artery theoretically causes local alkalosis a retrospective necropsy study was carried out to examine the relation between metastatic pulmonary calcification and vascular obstruction. METHODS: Five patients with focal and two with diffuse metastatic calcification in the lungs were identified over eight years. Lungs were studied macroscopically and by light microscopy, haematoxylin and eosin and histochemical stains being used for calcium. RESULTS: Underlying risk factors for calcification in these patients included renal failure in six and disseminated malignancy in five. In the five patients with localised calcification obstruction of the pulmonary artery by thrombus or tumour was found proximal or adjacent to areas of calcium deposition. In two patients metastatic calcification was confined to a lung with unilateral pulmonary artery thromboembolic occlusion. Calcification was not specifically associated with infarction, pneumonia, or diffuse alveolar damage. Lesions of the pulmonary artery were not seen in the two patients with diffuse bilateral metastatic calcification. CONCLUSION: In this small series there was a spatial association between pulmonary artery obstruction and localised metastatic calcification. It is proposed that pulmonary artery obstruction alters the microchemical environment of the lung, favouring tissue alkalosis and thereby enhancing parenchymal calcification in patients predisposed to this condition. Images PMID:1519194

  3. The role of inflammation in coronary artery calcification.

    PubMed

    Li, Jian-Jun; Zhu, Chen-Gang; Yu, Bing; Liu, Ya-Xin; Yu, Meng-Yue

    2007-12-01

    Vascular calcification is an age-dependent, common finding in human coronary arteries and begins as early as the second decade of life, just after fatty streak formation. Previous studies have showed that the severity of coronary calcification is closely related to atherosclerotic plaque burden and cardiac event rate. In the past few decades, coronary calcification has been considered passive and degenerative. With recent clinical and basic research, however, there is increasing recognition that coronary calcification is an active, regulated process. Current diagnostic methods for coronary artery calcification (CAC) are usually traditional coronary angiography, intravascular ultrasound (IVUS), electron beam computed tomography (EBCT) and multi-slice computed tomography (MSCT) while treatment for patients with calcified coronary arteries is troublesome. Several lines of evidence suggest that inflammation plays a major role in the development of atherosclerosis as well as its clinical manifestations. Recent study showed that inflammatory process might be also involved in coronary calcification. Accordingly, measurements of inflammatory markers such as C-reactive protein (CRP) may in part reflect indices of atherosclerosis, such as coronary calcification, and are likely to provide distinct information regarding cardiovascular risk. In this article, we review the current evidence of relationship between coronary calcification and inflammation for purpose of drawing the more attention on the inflammatory mechanism of coronary calcification, which may change our research as well as therapeutic strategies for coronary calcification in the future. PMID:17964226

  4. Do the cup surface properties influence the initial stability?

    PubMed

    Goriainov, Vitali; Jones, Andrew; Briscoe, Adam; New, Andrew; Dunlop, Douglas

    2014-04-01

    This project tests the relationship between the acetabular cup surface characteristics and their initial stability by comparing uncemented (Trabecular Metal (TM) and Trilogy) and cemented polyethylene shells. We hypothesised that different surface properties of uncemented cups will influence the cup stability. Mounted directly onto host bone, TM and cemented cups were significantly more stable than Trilogy cups (P < 0.01), with minimal difference between TM and cemented cups (P > 0.1). On 100% graft bed, there was marginal difference between all three cup types (P > 0.1). Incremental cavitary and segmental defects resulted in reducing stability, with cemented cups being minimally more stable (P > 0.1). TM cups possess satisfactory initial stability in bone graft constructs. This study demonstrates that TM shells are marginally less stable than cemented cups in the absence of significant host bone contact.

  5. Unusual ganglioglioma with extensive calcification and ossification.

    PubMed

    Kavishwar, Vikas Shashikant; Chadha, Kirti G; Barodawala, Shaikhali Moiz; Murthy, Anuradha Krishna

    2016-01-01

    Ganglioglioma is a slow-growing relatively low-grade mixed glioneuronal tumor with most cases corresponding to the WHO Grade I category. It frequently presents with seizures. The temporal lobe is the most common location followed by frontal, parietal, and occipital lobes. These generally behave in a benign fashion and have a favorable prognosis. We describe a case of a 24-year-old male presenting with convulsions and a calcified parieto-occipital mass. This mass removed from the parietal lobe showed neoplastic glial and dysplastic neuronal tissue amidst extensive areas of calcification and foci of ossification. On immunohistochemistry, the glial component expressed glial fibrillary acidic protein whereas the dysplastic neuronal component expressed synaptophysin and CD34. Epithelial membrane antigen was negative and Ki-67 showed a low proliferative index. After the surgery, the patient is free of neurological symptoms. Widespread calcification and ossification are very unusual in ganglioglioma, which prompted us to report this case. PMID:27510688

  6. Computed tomographic evaluation of pineal calcification.

    PubMed

    Kohli, N; Rastogi, H; Bhadury, S; Tandon, V K

    1992-04-01

    A prospective study to ascertain the incidence of normally calcified pineal gland, was carried out in 1000 consecutive patients from different parts of Uttar Pradesh (India), undergoing cranial computed tomography for reasons other than a pineal or parapineal pathology. A total of 167 (16.70%) patients were found to have calcified pineals. Of these 128 were males and 39 females. The incidence rose from 1.16 per cent in the first decade to 31.88 per cent above the age of 50 yr. The percentage incidence of normal pineal calcification was lower than that seen in the Western population. No significant difference was found between men and women in any age group. Although calcification appeared as early as the first decade, this percentage was significantly lower than in the higher age groups. Significantly higher incidence rates were seen in the second decade, third decade and sixth decade onwards. PMID:1428055

  7. Vascular calcification in diabetes: mechanisms and implications.

    PubMed

    Snell-Bergeon, Janet K; Budoff, Matthew J; Hokanson, John E

    2013-06-01

    Cardiovascular disease (CVD) remains the leading cause of death among adults with diabetes, and CVD prevention remains a major challenge. Coronary artery calcium (CAC) score measured by electron beam tomography (EBT) or multi-slice detector computed tomography correlates closely with plaque burden and coronary angiography, and predicts coronary events independently of other risk factors. Further, progression of CAC over several years has been shown to predict increased mortality. Coronary calcification is an active process strongly associated with atherosclerotic plaque evolution and is an accepted surrogate endpoint in studies of patients with diabetes older than 30. In this review, recent findings regarding the mechanisms and implications of vascular calcification in diabetes will be discussed. PMID:23526400

  8. Dystrophic Calcification of the Prostate after Cryotherapy

    PubMed Central

    2014-01-01

    We present a previously undocumented complication of dystrophic calcification of the prostate after cryotherapy. An 87-year-old male presented with recurrent lower urinary tract infections and was found to have an obstructing large calcified mass in the right lobe of the prostate. Subsequently, he underwent transurethral resection of the prostate (TURP) and bladder neck with laser lithotripsy to remove the calculus. We propose that chronic inflammation and necrosis of the prostate from cryotherapy resulted in dystrophic calcification of the prostate. As the use of cryotherapy for the treatment of localized prostate cancer continues to increase, it is important that clinicians be aware of this scenario and the technical challenges it poses. PMID:25548712

  9. Enlarging mediastinal/hilar lymphadenopathy with calcification.

    PubMed

    Adachi, Takashi; Nakahata, Masashi; Moritani, Suzuko; Iida, Hiroatsu; Ogawa, Kenji

    2016-02-01

    A 77-year-old man was referred to our hospital due to enlarging mediastinal/hilar lymphadenopathy with calcification. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and bone marrow aspiration were performed. Subsequently, monoclonal gammopathy of undetermined significance (MGUS) associated with mediastinal amyloidosis was diagnosed. We hereby report a case in which EBUS-TBNA led to a successful diagnosis of amyloidosis. PMID:26862422

  10. Influence of humic acid applications on soil physicochemical properties

    NASA Astrophysics Data System (ADS)

    Gümüş, İ.; Şeker, C.

    2015-09-01

    Soil structure is often said to be the key to soil productivity since a fertile soil, with desirable soil structure and adequate moisture supply, constitutes a productive soil. Soil structure influences soil water movement and retention, erosion, crusting, nutrient recycling, root penetration and crop yield. The objective of this work is to study, humic acid (HA) application on some physical and chemical properties in weak structured soils investigated. The approach involved establishing a plot experiment in the laboratory conditions. Different rates of HA (control, 0.5, 1, 2 and 4 %) were applied to soil at three incubation periods (21, 42 and 62 days). At the end of the each incubation period, the changes in physicochemical properties were measured. Generally, HA addition increased EC values at the all incubation periods. HA applications decreased soil modulus of rupture. Application of HA at the rate of 4 % was significantly increased soil organic carbon contents. HA applications at the rate of 4 % significantly increased both mean soil total nitrogen content and aggregate stability after at three incubation periods (p < 0.05). Therefore, HA was potential to improve structure of soil in short term.

  11. Surface defects and their influence on surface properties

    NASA Astrophysics Data System (ADS)

    Rodríguez de la Fuente, O.; González-Barrio, M. A.; Navarro, V.; Pabón, B. M.; Palacio, I.; Mascaraque, A.

    2013-12-01

    Surface defects have a profound influence on many attributes of materials, therefore experimental techniques and specific studies focused on their controlled generation and properties are mandatory. We have carried out a thorough study of the role of surface defects on a variety of physico-chemical properties of metals and oxides, using different experimental techniques and molecular dynamics simulations. In particular, we have studied the defects formed upon bombardment with Ar+ ions in a reconstructed Au(100) surface at very low ion doses. At room temperature, the pristine defects are mainly single vacancies, which diffuse by collective atomic motions, then cluster and collapse, resulting in 2D dislocation dipoles. These dislocations exhibit an enhanced chemical reactivity due to the elastic stress of their cores. We have also performed indentation tests of flat and stepped Au(111) samples with an atomic force microscope, revealing noticeable differences in their mechanical behavior when probed at the nanoscale. Thus, the stepped sample has a 20% smaller Young’s modulus, 40% smaller yield point and 50% smaller shear stress. These differences, as well as reversible, quasiplastic behavior of the stepped sample up to a critical load, are due to the active role of steps as dislocation nucleation centers. In contrast, a TiO2(110) surface, modified with ion bombardment, does not show noticeable changes in its nanomechanical properties, which is an indication of the very different mechanical responses of oxides compared to simple metals at the nanoscale. Finally, we show how surface defects affect the chemical activity of a Pt(111) surface when exposed to methanol. The nature of the adsorbed species and the dynamics of the surface reactions are modified in the presence of surface defects, rendering the defective surface into a more robust state against catalytic poisoning.

  12. Mild hyperthermia influence on Herceptin® properties

    PubMed Central

    Escoffre, Jean-Michel; Deckers, Roel; Sasaki, Noboru; Bos, Clemens; Moonen, Chrit

    2015-01-01

    Background Mild hyperthermia (mHT) increases the tumor perfusion and vascular permeability, and reduces the interstitial fluid pressure, resulting in better intra-tumoral bioavailability of low molecular weight drugs. This approach is potentially also attractive for delivery of therapeutic macromolecules, such as antibodies. Here, we investigated the effects of mHT on the stability, immunological and pharmacological properties of Herceptin®, a clinically approved antibody, targeting the human epidermal growth factor receptor 2 (HER-2) overexpressed in breast cancer. Results Herceptin® was heated to 37°C (control) and 42°C (mHT) for 1 hour. Formation of Herceptin® aggregates was measured using Nile Red assay. mHT did not result in additional Herceptin® aggregates compared to 37°C, showing the Herceptin® stability is unchanged. Immunological and pharmacological properties of Herceptin® were evaluated following mHT using HER-2 positive breast cancer cells (BT-474). Exposure of Herceptin® to mHT preserved recognition and binding affinity of Herceptin® to HER-2. Western-blot and cell proliferation assays on BT-474 cells showed that mHT left the inhibitory activities of Herceptin® unchanged. Conclusions The stability, and the immunological and pharmacological properties of Herceptin® are not negatively affected by mHT. Further in-vivo studies are required to evaluate the influence of mHT on intra-tumoral bioavailability and therapeutic effectiveness of Herceptin®. PMID:25810700

  13. Bicarbonate-sensitive calcification and lifespan of klotho-deficient mice.

    PubMed

    Leibrock, Christina B; Voelkl, Jakob; Kohlhofer, Ursula; Quintanilla-Martinez, Leticia; Kuro-O, Makoto; Lang, Florian

    2016-01-01

    Klotho, a protein counteracting aging, is a powerful inhibitor of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] formation and regulator of mineral metabolism. In klotho hypomorphic (kl/kl) mice, excessive 1,25(OH)2D3 formation leads to hypercalcemia, hyperphosphatemia and vascular calcification, severe growth deficits, accelerated aging and early death. Kl/kl mice further suffer from extracellular volume depletion and hypotension, leading to the stimulation of antidiuretic hormone and aldosterone release. A vitamin D-deficient diet, restriction of dietary phosphate, inhibition of mineralocorticoid receptors with spironolactone, and dietary NaCl all extend the lifespan of kl/kl mice. Kl/kl mice suffer from acidosis. The present study explored whether replacement of tap drinking water by 150 mM NaHCO3 affects the growth, tissue calcification, and lifespan of kl/kl mice. As a result, NaHCO3 administration to kl/kl mice did not reverse the growth deficit but substantially decreased tissue calcification and significantly increased the average lifespan from 78 to 127 days. NaHCO3 did not significantly affect plasma concentrations of 1,25(OH)2D3 and Ca(2+) but significantly decreased plasma phosphate concentration and plasma aldosterone concentration. The present study reveals a novel effect of bicarbonate, i.e., a favorable influence on vascular calcification and early death of klotho-deficient mice. PMID:26538435

  14. Treatment of hypophosphatemic rickets in generalized arterial calcification of infancy (GACI) without worsening of vascular calcification.

    PubMed

    Ferreira, Carlos R; Ziegler, Shira G; Gupta, Ashutosh; Groden, Catherine; Hsu, Kevin S; Gahl, William A

    2016-05-01

    Patients with generalized arterial calcification of infancy (GACI) develop vascular calcifications early in life. About half of them die within the first 6 months despite optimal medical care. A subset of those who survive eventually develop hypophosphatemic rickets. Since hypophosphatemia and hyperphosphaturia have been previously associated with increased survival in GACI patients, physicians often avoid phosphate repletion as treatment for rickets. As a consequence, GACI patients develop severe rachitic complications such as short stature and skeletal deformities. It appears that the recognition of hypophosphatemia later in life in some GACI patients is a consequence of having survived the first few months of life, and not the cause of their survival per se. Here, we report the long-term follow-up of a GACI patient who was phosphate-repleted for his rickets for more than 7 years without worsening of vascular calcification.

  15. Corals concentrate dissolved inorganic carbon to facilitate calcification.

    PubMed

    Allison, Nicola; Cohen, Itay; Finch, Adrian A; Erez, Jonathan; Tudhope, Alexander W

    2014-12-22

    The sources of dissolved inorganic carbon (DIC) used to produce scleractinian coral skeletons are not understood. Yet this knowledge is essential for understanding coral biomineralization and assessing the potential impacts of ocean acidification on coral reefs. Here we use skeletal boron geochemistry to reconstruct the DIC chemistry of the fluid used for coral calcification. We show that corals concentrate DIC at the calcification site substantially above seawater values and that bicarbonate contributes a significant amount of the DIC pool used to build the skeleton. Corals actively increase the pH of the calcification fluid, decreasing the proportion of DIC present as CO2 and creating a diffusion gradient favouring the transport of molecular CO2 from the overlying coral tissue into the calcification site. Coupling the increases in calcification fluid pH and [DIC] yields high calcification fluid [CO3(2-)] and induces high aragonite saturation states, favourable to the precipitation of the skeleton.

  16. Effect of alternative crosslinking techniques on the enzymatic degradation of bovine pericardia and their calcification.

    PubMed

    Vasudev, S C; Chandy, T

    1997-06-01

    The in vitro calcification and enzymatic degradation of bovine pericardia (BP) after a series of surface treatments were studied as a function of exposure time. The degradation of these treated surfaces was monitored by scanning electron micrography and tensile strength measurements. Polyethylene glycol-(PEG) grafted BP and glutaraldehyde-(GA) treated BPs retained maximum stability in collagenase digestion compared with SDS-treated BP. The ability of alpha chymotrypsin, bromelain, esterase, trypsin, and collagenase to modulate the degradation of SDS-, GA-, PEG-, Carbodiimide-, and glycidylether-treated BPs also was investigated. Incubation of various enzymes to these crosslinked pericardia variably reduced the tensile strength of these tissues. It is conceivable that chemical treatments of pericardial tissues might have altered their physical and chemical configuration and the subsequent degradation properties. In vitro calcification studies showed a substantial reduction in the calcification profile of PEG-grafted bovine pericardia compared to other treated tissues. Furthermore, the biocompatibility aspects of pericardial tissues were established by platelet adhesion and octane contact angle. In conclusion, it seems that the surface modification of bovine pericardia via GA-PEG grafting may provide new ways of controlling biodegradation and calcification.

  17. Dystrophic calcifications after autologous fat injection on face.

    PubMed

    Kim, Dai Hyun; Jang, Hee Won; Kim, Hee Joo; Son, Sang Wook

    2014-06-01

    Autologous fat injection is widely used procedure for various functional and aesthetic purposes. However, it could result in many immediate or delayed complications including dystrophic calcifications. Almost all of the case reports about dystrophic calcification after autologous fat injection were result from the iatrogenic tissue trauma of breast augmentation. This is a report of a 30-year-old patient who developed pathologically proven multiple dystrophic calcifications on the face after autologous fat injection. PMID:24131074

  18. Atraumatic quadriceps tendon tear associated with calcific tendonitis.

    PubMed

    Abram, Simon G F; Sharma, Akash D; Arvind, Chinnakonda

    2012-11-27

    Calcific tendonitis of the quadriceps tendon is an uncommon condition. We present the first case of a quadriceps tendon tear associated with calcific tendonitis. In this case, the patient presented with symptoms mimicking a rupture of the quadriceps tendon. This case illustrates that although calcific tendonitis of the quadriceps is a rare condition it is not benign and should be considered when investigating acute symptoms associated with the extensor mechanism of the knee.

  19. Sortilin mediates vascular calcification via its recruitment into extracellular vesicles

    PubMed Central

    Goettsch, Claudia; Hutcheson, Joshua D.; Aikawa, Masanori; Iwata, Hiroshi; Pham, Tan; Nykjaer, Anders; Kjolby, Mads; Rogers, Maximillian; Michel, Thomas; Shibasaki, Manabu; Hagita, Sumihiko; Kramann, Rafael; Singh, Sasha A.

    2016-01-01

    Vascular calcification is a common feature of major cardiovascular diseases. Extracellular vesicles participate in the formation of microcalcifications that are implicated in atherosclerotic plaque rupture; however, the mechanisms that regulate formation of calcifying extracellular vesicles remain obscure. Here, we have demonstrated that sortilin is a key regulator of smooth muscle cell (SMC) calcification via its recruitment to extracellular vesicles. Sortilin localized to calcifying vessels in human and mouse atheromata and participated in formation of microcalcifications in SMC culture. Sortilin regulated the loading of the calcification protein tissue nonspecific alkaline phosphatase (TNAP) into extracellular vesicles, thereby conferring its calcification potential. Furthermore, SMC calcification required Rab11-dependent trafficking and FAM20C/casein kinase 2–dependent C-terminal phosphorylation of sortilin. In a murine model, Sort1-deficiency reduced arterial calcification but did not affect bone mineralization. Additionally, transfer of sortilin-deficient BM cells to irradiated atherosclerotic mice did not affect vascular calcification, indicating a primary role of SMC-derived sortilin. Together, the results of this study identify sortilin phosphorylation as a potential therapeutic target for ectopic calcification/microcalcification and may clarify the mechanism that underlies the genetic association between the SORT1 gene locus and coronary artery calcification. PMID:26950419

  20. Inhibitory Role of Notch1 in Calcific Aortic Valve Disease

    PubMed Central

    Koenig, Sara N.; Nichols, Haley A.; Galindo, Cristi L.; Garner, Harold R.; Merrill, Walter H.; Hinton, Robert B.; Garg, Vidu

    2011-01-01

    Aortic valve calcification is the most common form of valvular heart disease, but the mechanisms of calcific aortic valve disease (CAVD) are unknown. NOTCH1 mutations are associated with aortic valve malformations and adult-onset calcification in families with inherited disease. The Notch signaling pathway is critical for multiple cell differentiation processes, but its role in the development of CAVD is not well understood. The aim of this study was to investigate the molecular changes that occur with inhibition of Notch signaling in the aortic valve. Notch signaling pathway members are expressed in adult aortic valve cusps, and examination of diseased human aortic valves revealed decreased expression of NOTCH1 in areas of calcium deposition. To identify downstream mediators of Notch1, we examined gene expression changes that occur with chemical inhibition of Notch signaling in rat aortic valve interstitial cells (AVICs). We found significant downregulation of Sox9 along with several cartilage-specific genes that were direct targets of the transcription factor, Sox9. Loss of Sox9 expression has been published to be associated with aortic valve calcification. Utilizing an in vitro porcine aortic valve calcification model system, inhibition of Notch activity resulted in accelerated calcification while stimulation of Notch signaling attenuated the calcific process. Finally, the addition of Sox9 was able to prevent the calcification of porcine AVICs that occurs with Notch inhibition. In conclusion, loss of Notch signaling contributes to aortic valve calcification via a Sox9-dependent mechanism. PMID:22110751

  1. Sortilin mediates vascular calcification via its recruitment into extracellular vesicles.

    PubMed

    Goettsch, Claudia; Hutcheson, Joshua D; Aikawa, Masanori; Iwata, Hiroshi; Pham, Tan; Nykjaer, Anders; Kjolby, Mads; Rogers, Maximillian; Michel, Thomas; Shibasaki, Manabu; Hagita, Sumihiko; Kramann, Rafael; Rader, Daniel J; Libby, Peter; Singh, Sasha A; Aikawa, Elena

    2016-04-01

    Vascular calcification is a common feature of major cardiovascular diseases. Extracellular vesicles participate in the formation of microcalcifications that are implicated in atherosclerotic plaque rupture; however, the mechanisms that regulate formation of calcifying extracellular vesicles remain obscure. Here, we have demonstrated that sortilin is a key regulator of smooth muscle cell (SMC) calcification via its recruitment to extracellular vesicles. Sortilin localized to calcifying vessels in human and mouse atheromata and participated in formation of microcalcifications in SMC culture. Sortilin regulated the loading of the calcification protein tissue nonspecific alkaline phosphatase (TNAP) into extracellular vesicles, thereby conferring its calcification potential. Furthermore, SMC calcification required Rab11-dependent trafficking and FAM20C/casein kinase 2-dependent C-terminal phosphorylation of sortilin. In a murine model, Sort1-deficiency reduced arterial calcification but did not affect bone mineralization. Additionally, transfer of sortilin-deficient BM cells to irradiated atherosclerotic mice did not affect vascular calcification, indicating a primary role of SMC-derived sortilin. Together, the results of this study identify sortilin phosphorylation as a potential therapeutic target for ectopic calcification/microcalcification and may clarify the mechanism that underlies the genetic association between the SORT1 gene locus and coronary artery calcification. PMID:26950419

  2. Influence of isomerization on nonlinear optical properties of molecules.

    PubMed

    Kinnibrugh, T; Bhattacharjee, S; Sullivan, P; Isborn, C; Robinson, B H; Eichinger, B E

    2006-07-13

    The influence of rotational and geometrical isomerism on the nonlinear optical (NLO) properties, specifically the first-order hyperpolarizability beta, of chromophores of current interest has been investigated with density functional theory (DFT). In the first of this two-part study, the rotational isomerism of a linear chromophore was explored. Calculation of the torsion potentials about two of the rotatable and conformation-changing single bonds in a chromophore demonstrated the near equality of the molecular energies at 0 degrees and 180 degrees rotational angles. To explore the consequences of this near conformational energy degeneracy to NLO behavior, the eight low energy rotational isomers of FTC [Robinson, B. H.; et al. Chem. Phys. 1999, 245, 35] were investigated. This study provides the first-reported DFT-based calculation of the statistical mechanical average of beta over the conformational space of a molecule having substantial nonlinear optical behavior. The influence of the solvent reaction field on rotameric populations and on the beta tensor is reported. In the second part, two molecules having two donors and two acceptors bonded respectively in ortho and meta positions on a central benzene ring are shown to have substantially different beta tensors. These two so-called molecular Xs have different highest occupied molecular orbital to lowest unoccupied molecular orbital (HOMO-LUMO) distributions, and consistent with expectations, it is found that the larger beta(zzz) is associated with a large spatial asymmetry between the HOMOs and LUMOs. Large hyperpolarizability correlates with the HOMO concentrated on the donor groups and the LUMO on the acceptor groups. PMID:16821878

  3. Contrasts in the Sensitivity of Community Calcification to Saturation State Variability Within Temperate and Tropical Marine Environments

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, L.

    2015-12-01

    Ongoing emissions of carbon dioxide (CO2) and invasion of part of this CO2 into the oceans are projected to lower the calcium carbonate saturation state. As a result, the ability of many marine organisms to calcify may be compromised, with significant impacts on ocean ecosystems throughout the Anthropocene. In laboratory manipulations, calcifying organisms have exhibited reduced calcification under elevated pCO2 conditions. However, very few experiments have observed how in situ community calcification, which incorporates complex species interactions, responds to natural variations in carbonate chemistry. Using intensive seawater sampling techniques we assess the community level sensitivity of calcification rates to natural variability in the aragonite saturation state (Ωarag) at both a tropical coral reef and temperate intertidal study site. Both sites experiences large daily variation in Ωarag during low tide due to photosynthesis, respiration, and the time at which the sites are isolated from the open ocean. On hourly timescales, we find that community level rates of calcification have only a weak dependence on variability in Ωarag at the tropical study site. At the temperate study site, although weak Ωarag sensitivity is observed during the day, nighttime community calcification rates are found to be strongly influenced by variability in Ωarag, with greater dissolution rates at lower Ωarag levels. If the short-term sensitivity of community calcification to Ωarag described here is representative of the long-term sensitivity of marine ecosystems to ocean acidification, then one would expect temperate intertidal calcifying communities to be more vulnerable than tropical coral reef calcifying communities. In particular, reductions in net community calcification, in the temperate intertidal zone may be predominately due to the nocturnal impact of ocean acidification.

  4. Calcific Aortic Valve Disease Is Associated with Layer-Specific Alterations in Collagen Architecture

    PubMed Central

    Hutson, Heather N.; Marohl, Taylor; Anderson, Matthew; Eliceiri, Kevin; Campagnola, Paul

    2016-01-01

    Disorganization of the valve extracellular matrix (ECM) is a hallmark of calcific aortic valve disease (CAVD). However, while microarchitectural features of the ECM can strongly influence the biological and mechanical behavior of tissues, little is known about the ECM microarchitecture in CAVD. In this work, we apply advanced imaging techniques to quantify spatially heterogeneous changes in collagen microarchitecture in CAVD. Human aortic valves were obtained from individuals between 50 and 75 years old with no evidence of valvular disease (healthy) and individuals who underwent valve replacement surgery due to severe stenosis (diseased). Second Harmonic Generation microscopy and subsequent image quantification revealed layer-specific changes in fiber characteristics in healthy and diseased valves. Specifically, the majority of collagen fiber changes in CAVD were found to occur in the spongiosa, where collagen fiber number increased by over 2-fold, and fiber width and density also significantly increased. Relatively few fibrillar changes occurred in the fibrosa in CAVD, where fibers became significantly shorter, but did not otherwise change in terms of number, width, density, or alignment. Immunohistochemical staining for lysyl oxidase showed localized increased expression in the diseased fibrosa. These findings reveal a more complex picture of valvular collagen enrichment and arrangement in CAVD than has previously been described using traditional analysis methods. Changes in fiber architecture may play a role in regulating the pathobiological events and mechanical properties of valves during CAVD. Additionally, characterization of the ECM microarchitecture can inform the design of fibrous scaffolds for heart valve tissue engineering. PMID:27685946

  5. Magnesium intake is inversely associated with coronary artery calcification: the Framingham Heart Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OBJECTIVES: The aim of this study was to examine whether magnesium intake is associated with coronary artery calcification (CAC) and abdominal aortic calcification (AAC). BACKGROUND: Animal and cell studies suggest that magnesium may prevent calcification within atherosclerotic plaques underlying c...

  6. Calcification and photosynthesis of the coral acropora cervicornis under calcium limited conditions

    NASA Technical Reports Server (NTRS)

    Rathfon, Megan; Brewer, Debbie

    1997-01-01

    Differing hypothesis about the function of calcification are based on an interesting dilemma. Is the purpose of calcification mainly a structural and protective one or does calcification serve other functions? Does photosynthesis increase carbonate ion activity and cause calcification or does calcification increase CO2 levels and stimulate photsynthesis? It is proposed that calcification in corals is not dependent upon photosynthesis but upon calcium levels in the water. Under normal ocean conditions, corals convert a certain percentage of energy to photosynthesis and respiration and another percentage to calcification. As corals become nutrient stressed, particularly calcium limited, the ratio of photosynthesis to calcification shifts towards calcification in order to generate protons. The protons generated during calcification may stimulate photosynthesis and aid in the uptake of nutrients and biocarbonates. The results of the calcification experiment show a trend towards increased calcification and decreased photosynthesis when the coral Acropora cervicornis is calcium limited, but the data are inconclusive and further research is needed.

  7. Environmental control on Emiliania huxleyi coccolithophore calcification in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    D'Amario, Barbara; Grelaud, Michael; Ziveri, Patrizia

    2016-04-01

    The Mediterranean Sea, a "natural laboratory" characterized by strong environmental gradients, is likely to undergo serious alterations due to climate change and ocean acidification. These processes are expected to affect also phytoplankton distribution. Coccolithophores are the only phytoplankton calcifying group and laboratory studies on E. huxleyi, the most abundant and widely distributed species of coccolithophores worldwide, yield strain-specific results. Culture experiments must be integrated with observations in the natural environment to understand existing interactions between drivers, and to verify population structures in different areas. Two transects spanning the south-western and south-eastern basins have been investigated, combining data from April 2011 (Meteor cruise M84/3) and May 2013 (MedSeA cruise). E. huxleyi coccolith morphometry was analyzed to determine average mass and length. These results were then compared with morphological observations performed on the largely dominant E. huxleyi Type A through scanning electron microscope (SEM). We distinguished four main calcification morphologies within E. huxleyi Type A: low-calcified (A1), medium-calcified (A2), high-calcified with closed central area (A3a), and open central area (A3b). E. huxleyi coccolith mass was strongly and positively correlated with the relative abundance of a particular morphology. Moreover, the calcification morphologies were preferentially distributed in the Mediterranean according to specific combinations of environmental variables, which included the carbonate chemistry system. The distribution of E. huxleyi Type A calcification morphologies in the Mediterranean is likely to be influenced by climate changes. Coccolithophore calcification degree is connected to the carbon cycle through photosynthesis / calcification ratio and sedimentation (particulate inorganic and organic carbon reaching the seafloor). This study aims to provide a basis for future investigations on the

  8. High-Flux Hemodialysis and High-Volume Hemodiafiltration Improve Serum Calcification Propensity

    PubMed Central

    Dekker, Marijke; Pasch, Andreas; van der Sande, Frank; Konings, Constantijn; Bachtler, Matthias; Dionisi, Mauro; Meier, Matthias; Kooman, Jeroen; Canaud, Bernard

    2016-01-01

    Background Calciprotein particles (CPPs) may play an important role in the calcification process. The calcification propensity of serum (T50) is highly predictive of all-cause mortality in chronic kidney disease patients. Whether T50 is therapeutically improvable, by high-flux hemodialysis (HD) or hemodiafiltration (HDF), has not been studied yet. Methods We designed a cross-sectional single center study, and included stable prevalent in-center dialysis patients on HD or HDF. Patients were divided into two groups based on dialysis modality, were on a thrice-weekly schedule, had a dialysis vintage of > 3 months and vascular access providing a blood flow rate > 300 ml/min. Calcification propensity of serum was measured by the time of transformation from primary to secondary CPP (T50 test), by time-resolved nephelometry. Results We included 64 patients, mean convective volume was 21.7L (SD 3.3L). In the pooled analysis, T50 levels increased in both the HD and HDF group with pre- and post-dialysis (mean (SD)) of 244(64) - 301(57) and 253(55) - 304(61) min respectively (P = 0.43(HD vs. HDF)). The mean increase in T50 was 26.29% for HD and 21.97% for HDF patients (P = 0.61 (HD vs. HDF)). The delta values (Δ) of calcium, phosphate and serum albumin were equal in both groups. Baseline T50 was negatively correlated with phosphate, and positively correlated with serum magnesium and fetuin-A. The ΔT50 was mostly influenced by Δ phosphate (r = -0.342; P = 0.002 HD and r = -0.396; P<0.001 HDF) in both groups. Conclusions HD and HDF patients present with same baseline T50 calcification propensity values pre-dialysis. Calcification propensity is significantly improved during both HD and HDF sessions without significant differences between both modalities. PMID:27064679

  9. An experimental phantom study on the effect of calcifications on ultrasound shear wave elastography.

    PubMed

    Gregory, Adriana; Bayat, Mahdi; Denis, Max; Mehrmohammadi, Mohammad; Fatemi, Mostafa; Alizad, Azra

    2015-08-01

    In this study, we investigated the effects of single macrocalcifications and groups of microcalcifications on shear wave elastography. Supersonic shear imaging (SSI) and comb-push ultrasound shear elastography (CUSE) were performed on three sets of phantoms to investigate how calcifications of different sizes and distributions influence measured elasticity. Our results demonstrate that the presence of large isolated macrocalcifications and highly concentrated clusters of microcalcifications can introduce areas with apparent high elasticity when they are evaluated by shear wave elastography. PMID:26737132

  10. Secondary calcification and dissolution respond differently to future ocean conditions

    NASA Astrophysics Data System (ADS)

    Silbiger, N. J.; Donahue, M. J.

    2014-09-01

    Climate change threatens both the accretion and erosion processes that sustain coral reefs. Secondary calcification, bioerosion, and reef dissolution are integral to the structural complexity and long-term persistence of coral reefs, yet these processes have received less research attention than reef accretion by corals. In this study, we use climate scenarios from RCP8.5 to examine the combined effects of rising ocean acidity and SST on both secondary calcification and dissolution rates of a natural coral rubble community using a flow-through aquarium system. We found that secondary reef calcification and dissolution responded differently to the combined effect of pCO2 and temperature. Calcification had a non-linear response to the combined effect of pCO2-temperature: the highest calcification rate occurred slightly above ambient conditions and the lowest calcification rate was in the highest pCO2-temperature condition. In contrast, dissolution increased linearly with pCO2-temperature. The rubble community switched from net calcification to net dissolution at +272 μatm pCO2 and 0.84 °C above ambient conditions, suggesting that rubble reefs may shift from net calcification to net dissolution before the end of the century. Our results indicate that dissolution may be more sensitive to climate change than calcification, and that calcification and dissolution have different functional responses to climate stressors, highlighting the need to study the effects of climate stressors on both calcification and dissolution to predict future changes in coral reefs.

  11. Secondary calcification and dissolution respond differently to future ocean conditions

    NASA Astrophysics Data System (ADS)

    Silbiger, N. J.; Donahue, M. J.

    2015-01-01

    Climate change threatens both the accretion and erosion processes that sustain coral reefs. Secondary calcification, bioerosion, and reef dissolution are integral to the structural complexity and long-term persistence of coral reefs, yet these processes have received less research attention than reef accretion by corals. In this study, we use climate scenarios from RCP 8.5 to examine the combined effects of rising ocean acidity and sea surface temperature (SST) on both secondary calcification and dissolution rates of a natural coral rubble community using a flow-through aquarium system. We found that secondary reef calcification and dissolution responded differently to the combined effect of pCO2 and temperature. Calcification had a non-linear response to the combined effect of pCO2 and temperature: the highest calcification rate occurred slightly above ambient conditions and the lowest calcification rate was in the highest temperature-pCO2 condition. In contrast, dissolution increased linearly with temperature-pCO2 . The rubble community switched from net calcification to net dissolution at +271 μatm pCO2 and 0.75 °C above ambient conditions, suggesting that rubble reefs may shift from net calcification to net dissolution before the end of the century. Our results indicate that (i) dissolution may be more sensitive to climate change than calcification and (ii) that calcification and dissolution have different functional responses to climate stressors; this highlights the need to study the effects of climate stressors on both calcification and dissolution to predict future changes in coral reefs.

  12. Characterising the short-term sensitivity of Californian intertidal community calcification to ocean acidification

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, Lester; Caldeira, Ken

    2015-04-01

    Anthropogenic emissions of CO2 and invasion of part of this CO2 into the oceans results in a decrease in seawater pH and a lowering of the calcium carbonate saturation state. The historic and projected decrease of the calcium carbonate saturation state of seawater has the potential to compromise the ability of many marine calcifying organisms to form their calcium carbonate shells or skeletons and is likely to have significant ocean ecosystem impacts over the 21st Century. In laboratory manipulations temperate calcifying organisms have been shown to exhibit reduced calcification as a result of CO2 addition. However, very few experiments have observed how calcification in temperate systems responds to natural variations in seawater carbonate chemistry. We assess the community level sensitivity of Californian tidal pool calcification rates to variability in the calcium carbonate saturation state. Our tidal pool study sites at Bodega Bay in Northern California experience extreme variation in low tide carbonate saturation state due to photosynthetic activity and the time at which the pools are isolated from the open ocean. During our study period, we observed aragonite saturation levels ranging from 0.5 to 9. Photosynthetic activity is largely dependent on temperature and photosynthetic active radiation which vary on a diurnal timescale whereas the time at which pools are isolated from open seawater, and thus the amount by which tide pool carbonate chemistry differs from that of open ocean waters, is largely a consequence of tidal period which varies on a lunar cycle. Because there are substantial uncorrelated components of light, temperature, and seawater carbonate chemistry in our data, one can separate the influence of carbonate saturation state on calcification from the influence of temperature and PAR. This provides an opportunity to characterise the short-timescale sensitivity of tidal pool calcification rates to changes in carbonate saturation state. We show

  13. Calcific tendinitis of the rotator cuff

    PubMed Central

    ElShewy, Mohamed Taha

    2016-01-01

    Calcific tendinitis within the rotator cuff tendon is a common shoulder disorder that should be differentiated from dystrophic calcification as the pathogenesis and natural history of both is totally different. Calcific tendinitis usually occurs in the fifth and sixth decades of life among sedentary workers. It is classified into formative and resorptive phases. The chronic formative phase results from transient hypoxia that is commonly associated with repeated microtrauma causing calcium deposition into the matrix vesicles within the chondrocytes forming bone foci that later coalesce. This phase may extend from 1 to 6 years, and is usually asymptomatic. The resorptive phase extends from 3 wk up to 6 mo with vascularization at the periphery of the calcium deposits causing macrophage and mononuclear giant cell infiltration, together with fibroblast formation leading to an aggressive inflammatory reaction with inflammatory cell accumulation, excessive edema and rise of the intra-tendineous pressure. This results in a severely painful shoulder. Radiological investigations confirm the diagnosis and suggest the phase of the condition and are used to follow its progression. Although routine conventional X-ray allows detection of the deposits, magnetic resonance imaging studies allow better evaluation of any coexisting pathology. Various methods of treatment have been suggested. The appropriate method should be individualized for each patient. Conservative treatment includes pain killers and physiotherapy, or “minimally invasive” techniques as needling or puncture and aspiration. It is almost always successful since the natural history of the condition ends with resorption of the deposits and complete relief of pain. Due to the intolerable pain of the acute and severely painful resorptive stage, the patient often demands any sort of operative intervention. In such case arthroscopic removal is the best option as complete removal of the deposits is unnecessary. PMID

  14. Association between calcifying nanoparticles and placental calcification

    PubMed Central

    Guo, Yanan; Zhang, Dechun; Lu, He; Luo, Shuang; Shen, Xuecheng

    2012-01-01

    Background The purpose of this study was to examine the possible contribution of calcifying nanoparticles to the pathogenesis of placental calcification. Methods Calcified placental tissues and distal tissue samples were collected from 36 confirmed placental calcification cases. In addition, 20 normal placental tissue samples were obtained as a control group. All the tissue samples were cultured using special nanobacterial culture methods. The cultured calcifying nanoparticles were examined by transmission electron microscopy (TEM), and their growth was monitored by optical density (OD) at a wavelength of 650 nm. 16S rRNA gene expression of the cultured calcifying nanoparticles was also isolated and sequenced. Results Novel calcifying nanoparticles wrapped with electron-dense shells between 50 nm to 500 nm in diameter were observed in the extracellular matrix of calcified placental tissues. They were detected in placental villi and hydroxyapatite crystals, and contained “nucleic acid-like materials”. After isolation and four weeks of culture, 28 of 36 calcified placental tissue samples showed white granular precipitates attached to the bottom of the culture tubes. OD650 measurements indicated that the precipitates from the calcified placental tissues were able to grow in culture, whereas no such precipitates from the control tissues were observed. The 16S rRNA genes were isolated from the cultured calcifying nanoparticles and calcified placental tissues, and their gene sequencing results implied that calcifying nanoparticles were novel nanobacteria (GenBank JF823648). Conclusion Our results suggest that these novel calcifying nanoparticles may play a role in placental calcification. PMID:22615531

  15. Medial vascular calcification revisited: review and perspectives

    PubMed Central

    Lanzer, Peter; Boehm, Manfred; Sorribas, Victor; Thiriet, Marc; Janzen, Jan; Zeller, Thomas; St Hilaire, Cynthia; Shanahan, Catherine

    2014-01-01

    Vascular calcifications (VCs) are actively regulated biological processes associated with crystallization of hydroxyapatite in the extracellular matrix and in cells of the media (VCm) or intima (VCi) of the arterial wall. Both patterns of VC often coincide and occur in patients with type II diabetes, chronic kidney disease, and other less frequent disorders; VCs are also typical in senile degeneration. In this article, we review the current state of knowledge about the pathology, molecular biology, and nosology of VCm, expand on potential mechanisms responsible for poor prognosis, and expose some of the directions for future research in this area. PMID:24740885

  16. Ablation of the androgen receptor from vascular smooth muscle cells demonstrates a role for testosterone in vascular calcification

    PubMed Central

    Zhu, Dongxing; Hadoke, Patrick W. F.; Wu, Junxi; Vesey, Alex T.; Lerman, Daniel. A.; Dweck, Marc R.; Newby, David E.; Smith, Lee B.; MacRae, Vicky E.

    2016-01-01

    Vascular calcification powerfully predicts mortality and morbidity from cardiovascular disease. Men have a greater risk of cardiovascular disease, compared to women of a similar age. These gender disparities suggest an influence of sex hormones. Testosterone is the primary and most well-recognised androgen in men. Therefore, we addressed the hypothesis that exogenous androgen treatment induces vascular calcification. Immunohistochemical analysis revealed expression of androgen receptor (AR) in the calcified media of human femoral artery tissue and calcified human valves. Furthermore, in vitro studies revealed increased phosphate (Pi)-induced mouse vascular smooth muscle cell (VSMC) calcification following either testosterone or dihydrotestosterone (DHT) treatment for 9 days. Testosterone and DHT treatment increased tissue non-specific alkaline phosphatase (Alpl) mRNA expression. Testosterone-induced calcification was blunted in VSMC-specific AR-ablated (SM-ARKO) VSMCs compared to WT. Consistent with these data, SM-ARKO VSMCs showed a reduction in Osterix mRNA expression. However, intriguingly, a counter-intuitive increase in Alpl was observed. These novel data demonstrate that androgens play a role in inducing vascular calcification through the AR. Androgen signalling may represent a novel potential therapeutic target for clinical intervention. PMID:27095121

  17. [Endomyocardial fibrosis with massive calcification of the left ventricle].

    PubMed

    Trigo, Joana; Camacho, Ana; Gago, Paula; Candeias, Rui; Santos, Walter; Marques, Nuno; Matos, Pedro; Brandão, Victor; Gomes, Veloso

    2010-03-01

    Endomyocardial fibrosis is a rare disease, endemic in tropical countries. It is characterized by fibrosis of the endocardium that can extend to myocardium. Important calcification of the endocardium is rare with only a few cases reported in the literature. We report a case of endomyocardial fibrosis in a european caucasian patient, associated with massive calcification of left ventricle.

  18. Extracellular vesicles in cardiovascular calcification: expanding current paradigms.

    PubMed

    Krohn, Jona B; Hutcheson, Joshua D; Martínez-Martínez, Eduardo; Aikawa, Elena

    2016-06-01

    Vascular calcification is a major contributor to the progression of cardiovascular disease, one of the leading causes of death in industrialized countries. New evidence on the mechanisms of mineralization identified calcification-competent extracellular vesicles (EVs) derived from smooth muscle cells, valvular interstitial cells and macrophages as the mediators of calcification in diseased heart valves and atherosclerotic plaques. However, the regulation of EV release and the mechanisms of interaction between EVs and the extracellular matrix leading to the formation of destabilizing microcalcifications remain unclear. This review focuses on current limits in our understanding of EVs in cardiovascular disease and opens up new perspectives on calcific EV biogenesis, release and functions within and beyond vascular calcification. We propose that, unlike bone-derived matrix vesicles, a large population of EVs implicated in cardiovascular calcification are of exosomal origin. Moreover, the milieu-dependent loading of EVs with microRNA and calcification inhibitors fetuin-A and matrix Gla protein suggests a novel role for EVs in intercellular communication, adding a new mechanism to the pathogenesis of vascular mineralization. Similarly, the cell type-dependent enrichment of annexins 2, 5 or 6 in calcifying EVs posits one of several emerging factors implicated in the regulation of EV release and calcifying potential. This review aims to emphasize the role of EVs as essential mediators of calcification, a major determinant of cardiovascular mortality. Based on recent findings, we pinpoint potential targets for novel therapies to slow down the progression and promote the stability of atherosclerotic plaques. PMID:26824781

  19. Matrix Gla Protein polymorphisms are associated with coronary artery calcification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Matrix Gla Protein (MGP) is a key regulator of vascular calcification. Genetic variation at the MGP locus could modulate the development of coronary artery calcification (CAC). We examined the cross-sectional association between MGP SNPs [rs1800802 (T-138C), rs1800801 (G-7A),and rs4236 (Ala102Thr)...

  20. Liposarcoma of the thigh with mixed calcification and ossification.

    PubMed

    Child, Jeremy R; Young, Colin R; Amini, Behrang

    2016-09-01

    Liposarcoma is one of the most common soft-tissue sarcomas. Calcification and ossification can occur in liposarcoma; however, the presence of both ossification and calcification is a very rare entity. We present a case of a partially calcified and ossified dedifferentiated liposarcoma of the thigh in a 76-year-old woman, which contained heterologous elements of chondrosarcoma and rhabdomyosarcoma. PMID:27594953

  1. Activation of Nrf2 by dimethyl fumarate improves vascular calcification.

    PubMed

    Ha, Chae-Myeong; Park, Sungmi; Choi, Young-Keun; Jeong, Ji-Yun; Oh, Chang Joo; Bae, Kwi-Hyun; Lee, Sun Joo; Kim, Ji-Hyun; Park, Keun-Gyu; Jun, Do Youn; Lee, In-Kyu

    2014-10-01

    Dimethyl fumarate (DMF) has several pharmacological benefits including immunomodulation and prevention of fibrosis, which are dependent on the NF-E2-related factor 2 (Nrf2) antioxidant pathways. Therefore, we hypothesized that DMF could attenuate vascular calcification via Nrf2 activation. Vascular calcification induced by hyperphosphataemia was significantly inhibited by DMF in vascular smooth muscle cells (VSMCs) in a dose-dependent manner. DMF-mediated Nrf2 upregulation was accompanied by the reduced expressions of genes related with osteoblast-like phenotype based on promoter activity, mRNA and protein expression, and von Kossa staining. Likewise, Nrf2 overexpression significantly decreased the formation of calcium deposit similar to the level of osteogenic staining in VSMCs, and DMF with Nrf2 knockdown failed to attenuate hyperphosphatemia induced vascular calcification. Furthermore, DMF significantly attenuated the calcification of ex vivo ring culture from both rat common carotid artery and mouse thoracic aorta as well as in vivo mouse model of Vitamin D3-induced calcification consistent with the increased Nrf2 protein levels in early stage of calcification by DMF. In conclusion, our data support that DMF stimulates Nrf2 activity to attenuate hyperphosphatamia in vitro or Vitamin D3-induced in vivo vascular calcification, which would be a beneficial effect on vascular diseases induced by oxidative stress such as vascular calcification. PMID:25135648

  2. TBS Predict Coronary Artery Calcification in Adults

    PubMed Central

    Chuang, Tzyy-Ling; Hsiao, Fu-Tsung; Li, Yi-Da

    2016-01-01

    Purpose. This study analyzes the association between the bony microarchitecture score (trabecular bone score, TBS) and coronary artery calcification (CAC) in adults undergoing health exams. Materials and Methods. We retrospectively collected subjects (N = 81) who underwent coronary computed tomography and bone mineral density studies simultaneously. CAC was categorized to three levels (Group 0, G0, no CAC, score = 0, N = 45; Group 1, G1, moderate CAC, score = 1–100, N = 17; Group 2, G2, high CAC, score ≧ 101, N = 19). Multinomial logistic regression was used to study the association between TBS and CAC levels. Results. CAC is present in 44.4% of the population. Mean TBS ± SD was 1.399 ± 0.090. Per 1 SD increase in TBS, the unadjusted odds ratio (2.393) of moderate CAC compared with no CAC was significantly increased (95% CI, 1.219–4.696, p = 0.011). However, there has been no association of TBS with high CAC (OR: 1.026, 95% CI: 0.586–1.797, p = 0.928). These relationships also existed when individually adjusted for age, sex, and multiple other covariates. Conclusions. Higher TBS was related to moderate CAC, but not high CAC; a possible explanation may be that bone microarchitecture remodeling becomes more active when early coronary artery calcification occurs. However, further researches are needed to clarify this pathophysiology. PMID:27042671

  3. Mechanisms of ectopic calcification: implications for diabetic vasculopathy

    PubMed Central

    Fadini, Gian Paolo

    2015-01-01

    Vascular calcification (VC) is the deposition of calcium/phosphate in the vasculature, which portends a worse clinical outcome and predicts major adverse cardiovascular events. VC is an active process initiated and regulated via a variety of molecular signalling pathways. There are mainly two types of calcifications: the media VC and the intima VC. All major risk factors for cardiovascular disease (CVD) have been linked to the presence/development of VC. Besides the risk factors, a genetic component is also operative to determine arterial calcification. Several events take place before VC is established, including inflammation, trans-differentiation of vascular cells and homing of circulating pro-calcific cells. Diabetes is an important predisposing factor for VC. Compared with non-diabetic subjects, patients with diabetes show increased VC and higher expression of bone-related proteins in the medial layer of the vessels. In this review we will highlight the mechanisms underlying vascular calcification in diabetic patients. PMID:26543821

  4. Susceptibility weighted imaging: differentiating between calcification and hemosiderin*

    PubMed Central

    Barbosa, Jeam Haroldo Oliveira; Santos, Antonio Carlos; Salmon, Carlos Ernesto Garrido

    2015-01-01

    Objective To present a detailed explanation on the processing of magnetic susceptibility weighted imaging (SWI), demonstrating the effects of echo time and sensitive mask on the differentiation between calcification and hemosiderin. Materials and Methods Computed tomography and magnetic resonance (magnitude and phase) images of six patients (age range 41– 54 years; four men) were retrospectively selected. The SWI images processing was performed using the Matlab’s own routine. Results Four out of the six patients showed calcifications at computed tomography images and their SWI images demonstrated hyperintense signal at the calcification regions. The other patients did not show any calcifications at computed tomography, and SWI revealed the presence of hemosiderin deposits with hypointense signal. Conclusion The selection of echo time and of the mask may change all the information on SWI images, and compromise the diagnostic reliability. Amongst the possible masks, the authors highlight that the sigmoid mask allows for contrasting calcifications and hemosiderin on a single SWI image. PMID:25987750

  5. Cyanobacterial tufa calcification in two freshwater streams: ambient environment, chemical thresholds and biological processes

    NASA Astrophysics Data System (ADS)

    Merz-Preiß, Martina; Riding, Robert

    1999-07-01

    Calcareous freshwater streams near Bad Urach, southwest Germany, were studied to determine the environmental limits to cyanobacterial calcification. Daily variations in temperature, pH, calcium concentration, and alkalinity were measured at seasonal intervals from September 1993 to January 1995 in two small woodland streams with lengths of 1.0 and 1.5 km. The principal cause of supersaturation in these fast-flowing streams is inorganic carbon dioxide outgassing from resurging groundwater, locally enhanced by turbulence at waterfalls and cascades. Photosynthetic uptake of carbon dioxide and temperature effects are negligible. Nonetheless, organic substrates, particularly cyanobacteria-dominated microbial mats and biofilm, significantly localize precipitation by providing suitable nucleation sites. Precipitation rates on artificial substrates, up to 2.2 mm/yr on limestone, correlate with high Saturation Index values. Copper substrates inhibited microbial colonization and received negligible encrustation. Tufa formation and external calcium carbonate encrustation of cyanobacteria are conspicuous where the annual WATEQ4F Saturation Index exceeds 0.8, and are slightly below 0.7. Calcium carbonate impregnation of cyanobacterial sheaths has not been observed. We infer that in these fast-flowing streams cyanobacteria utilize CO 2 in photosynthesis whereas elsewhere, in sluggish freshwater, cyanobacteria utilize HCO 3-, leading to sheath impregnation by calcium carbonate even where Saturation Index is only 0.2-0.3. Thus, photosynthetic influence on cyanobacterial calcification appears to be negligible in fast-flowing CO 2-rich streams and cyanobacterial calcification takes the form of external encrustation. In slow-flowing CO 2-poor streams and lakes cyanobacteria preferentially utilize bicarbonate and sheath impregnation can result. Modern tropical marine carbonate shelves have saturation indices commonly in the range 0.62-0.82 and cyanobacterial calcification is

  6. A locus on chromosome 7 determines myocardial cell necrosis and calcification (dystrophic cardiac calcinosis) in mice.

    PubMed Central

    Ivandic, B T; Qiao, J H; Machleder, D; Liao, F; Drake, T A; Lusis, A J

    1996-01-01

    Dystrophic cardiac calcinosis, an age-related cardiomyopathy that occurs among certain inbred strains of mice, involves myocardial injury, necrosis, and calcification. Using a complete linkage map approach and quantitative trait locus analysis, we sought to identify genetic loci determining dystrophic cardiac calcinosis in an F2 intercross of resistant C57BL/6J and susceptible C3H/HeJ inbred strains. We identified a single major locus, designated Dyscalc, located on proximal chromosome 7 in a region syntenic with human chromosomes 19q13 and 11p15. The statistical significance of Dyscalc (logarithm of odds score 14.6) was tested by analysis of permuted trait data. Analysis of BxH recombinant inbred strains confirmed the mapping position. The inheritance pattern indicated that this locus influences susceptibility of cells both to enter necrosis and to subsequently undergo calcification. Images Fig. 1 Fig. 3 PMID:8643601

  7. ENPP1-Fc prevents mortality and vascular calcifications in rodent model of generalized arterial calcification of infancy

    PubMed Central

    Albright, Ronald A.; Stabach, Paul; Cao, Wenxiang; Kavanagh, Dillon; Mullen, Isabelle; Braddock, Alexander A.; Covo, Mariel S.; Tehan, Martin; Yang, Guangxiao; Cheng, Zhiliang; Bouchard, Keith; Yu, Zhao-Xue; Thorn, Stephanie; Wang, Xiangning; Folta-Stogniew, Ewa J.; Negrete, Alejandro; Sinusas, Albert J.; Shiloach, Joseph; Zubal, George; Madri, Joseph A.; De La Cruz, Enrique M.; Braddock, Demetrios T.

    2015-01-01

    Diseases of ectopic calcification of the vascular wall range from lethal orphan diseases such as generalized arterial calcification of infancy (GACI), to common diseases such as hardening of the arteries associated with aging and calciphylaxis of chronic kidney disease (CKD). GACI is a lethal orphan disease in which infants calcify the internal elastic lamina of their medium and large arteries and expire of cardiac failure as neonates, while calciphylaxis of CKD is a ubiquitous vascular calcification in patients with renal failure. Both disorders are characterized by vascular Mönckeburg's sclerosis accompanied by decreased concentrations of plasma inorganic pyrophosphate (PPi). Here we demonstrate that subcutaneous administration of an ENPP1-Fc fusion protein prevents the mortality, vascular calcifications and sequela of disease in animal models of GACI, and is accompanied by a complete clinical and biomarker response. Our findings have implications for the treatment of rare and common diseases of ectopic vascular calcification. PMID:26624227

  8. A red herring in vascular calcification: 'nanobacteria' are protein-mineral complexes involved in biomineralization.

    PubMed

    Schlieper, Georg; Krüger, Thilo; Heiss, Alexander; Jahnen-Dechent, Willi

    2011-11-01

    Biomineralization at pathological extraosseous sites (i.e. vasculature and soft tissues) is associated with increased morbidity and mortality. So-called 'nanobacteria' have been described as pathogenic agents causing many diseases including calcification. Initially, their appearance, and having a content consisting of nucleic acids plus proteins and properties of growing structures, suggested that they were living organisms. However, it could be demonstrated that the so-called nanobacteria were in fact mineralizing nanoparticles that contain mineral and non-mineral compounds, that these particles bind to charged molecules and that supersaturation enables in vitro growth of these nanoparticles. Recent data indicate that nanoparticles consisting of protein-mineral complexes can be seen both in vitro and in vivo as precursors of matrix calcification. PMID:21965584

  9. Aortic calcification produced by vitamin D3 plus nicotine.

    PubMed

    Niederhoffer, N; Bobryshev, Y V; Lartaud-Idjouadiene, I; Giummelly, P; Atkinson, J

    1997-01-01

    Calcification of the elastic arteries of the young rat by treatment with vitamin D and nicotine (VDN) has been proposed as an animal model of arterial calcification associated with age and age-related vascular pathology in man. The calcium-binding protein, S-100, which is found in human atherosclerotic lesions was associated with medial calcification of the aorta in VDN rats, especially in cases of severe calcification. Calcification (total calcium content: 366 +/- 87, n = 12 in VDN vs. 24 +/- 2 micromol g(-1) aortic dry weight in controls, n = 13) involved elastocalcinosis leading to elastolysis as revealed by a fall in the amount of desmosine and isodesmosine in the aortic wall (266 +/- 17 and 254 +/- 15 in VDN vs. 655 +/- 56 and 588 +/- 30 microg g(-1) aortic dry weight in controls). The decrease in elastin was associated with an increase in the stiffness of the aortic wall (elastic modulus: 15.1 +/- 1.8 in VDN vs. 6.7 +/- 0.5 10(6) dyn cm(-2) in controls), an increase in end-systolic stress (central systolic aortic pressure: 152 +/- 6 in VDN vs. 136 +/- 2 mm Hg in controls) (at a normotensive mean pressure level) and left ventricular hypertrophy (heart weight/body weight 2.51 +/- 0.10 in VDN vs. 2.24 +/- 0.07 g kg(-1) in controls). In conclusion, the mechanisms and consequences of aortic calcification in VDN show several similarities with calcification occurring in human athero- and arteriosclerosis.

  10. Observer study to evaluate the simulation of mammographic calcification clusters

    NASA Astrophysics Data System (ADS)

    Sousa, Maria A. Z.; Marcomini, Karem D.; Bakic, Predrag R.; Maidment, Andrew D. A.; Schiabel, Homero

    2016-03-01

    Numerous breast phantoms have been developed to be as realistic as possible to ensure the accuracy of image quality analysis, covering a greater range of applications. In this study, we simulated three different densities of the breast parenchyma using paraffin gel, acrylic plates and PVC films. Hydroxyapatite was used to simulate calcification clusters. From the images acquired with a GE Senographe DR 2000D mammography system, we selected 68 regions of interest (ROIs) with and 68 without a simulated calcification cluster. To validate the phantom simulation, we selected 136 ROIs from the University of South Florida's Digital Database for Screening Mammography (DDSM). Seven trained observers performed two observer experiments by using a high-resolution monitor Barco mod. E-3620. In the first experiment, the observers had to distinguish between real or phantom ROIs (with and without calcification). In the second one, the observers had to indicate the ROI with calcifications between a pair of ROIs. Results from our study show that the hydroxyapatite calcifications had poor contrast in the simulated breast parenchyma, thus observers had more difficulty in identifying the presence of calcification clusters in phantom images. Preliminary analysis of the power spectrum was conducted to investigate the radiographic density and the contrast thresholds for calcification detection. The values obtained for the power spectrum exponent (β) were comparable with those found in the literature.

  11. In-vitro calcification study of polyurethane heart valves.

    PubMed

    Boloori Zadeh, Parnian; Corbett, Scott C; Nayeb-Hashemi, Hamid

    2014-02-01

    Tri-leaflet polyurethane heart valves have been considered as a potential candidate in heart valve replacement surgeries. In this study, polyurethane (Angioflex(®)) heart valve prostheses were fabricated using a solvent-casting method to evaluate their calcification resistance. These valves were subjected to accelerated life testing (continuous opening and closing of the leaflets) in a synthetic calcification solution. Results showed that Angioflex(®) could be considered as a potential material for fabricating prosthetic heart valves with possibly a higher calcification resistance compared to tissue valves. In addition, calcification resistance of bisphosphonate-modified Angioflex(®) valves was also evaluated. Bisphosphonates are considered to enhance the calcification resistance of polymers once covalently bonded to the bulk of the material. However, our in-vitro results showed that bisphosphonate-modified Angioflex(®) valves did not improve the calcification resistance of Angioflex(®) compared to its untreated counterparts. The results also showed that cyclic loading of the valves' leaflets resulted in formation of numerous cracks on the calcified surface, which were not present when calcification study did not involve mechanical loading. Further study of these cracks did not result in enough evidence to conclude whether these cracks have penetrated to the polymeric surface.

  12. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Role of vascular smooth muscle cells in vascular calcification].

    PubMed

    Kurabayashi, Masahiko

    2015-05-01

    Vascular calcification is commonly seen with aging, chronic kidney disese (CKD), diabetes, and atherosclerosis, and is closely associated with cardiovascular morbidity and mortality. Vascular calcification has long been regarded as the final stage of degeneration and necrosis of arterial wall and a passive, unregulated process. However, it is now known to be an active and tightly regulated process involved with phenotypic transition of vascular smooth muscle cells (VSMC) that resembles bone mineralization. Briefly, calcium deposits of atherosclerotic plaque consist of hydroxyapatite and may appear identical to fully formed lamellar bone. By using a genetic fate mapping strategy, VSMC of the vascular media give rise to the majority of the osteochondrogenic precursor- and chondrocyte-like cells observed in the calcified arterial media of MGP (- / -) mice. Osteogenic differentiation of VSMC is characterized by the expression of bone-related molecules including bone morphogenetic protein (BMP) -2, Msx2 and osteopontin, which are produced by osteoblasts and chondrocytes. Our recent findings are that (i) Runx2 and Notch1 induce osteogenic differentiation, and (ii) advanced glycation end-product (AGE) /receptor for AGE (RAGE) and palmitic acid promote osteogenic differentiation of VSMC. To understand of the molecular mechanisms of vascular calcification is now under intensive research area. PMID:25926569

  13. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Role of vascular smooth muscle cells in vascular calcification].

    PubMed

    Kurabayashi, Masahiko

    2015-05-01

    Vascular calcification is commonly seen with aging, chronic kidney disese (CKD), diabetes, and atherosclerosis, and is closely associated with cardiovascular morbidity and mortality. Vascular calcification has long been regarded as the final stage of degeneration and necrosis of arterial wall and a passive, unregulated process. However, it is now known to be an active and tightly regulated process involved with phenotypic transition of vascular smooth muscle cells (VSMC) that resembles bone mineralization. Briefly, calcium deposits of atherosclerotic plaque consist of hydroxyapatite and may appear identical to fully formed lamellar bone. By using a genetic fate mapping strategy, VSMC of the vascular media give rise to the majority of the osteochondrogenic precursor- and chondrocyte-like cells observed in the calcified arterial media of MGP (- / -) mice. Osteogenic differentiation of VSMC is characterized by the expression of bone-related molecules including bone morphogenetic protein (BMP) -2, Msx2 and osteopontin, which are produced by osteoblasts and chondrocytes. Our recent findings are that (i) Runx2 and Notch1 induce osteogenic differentiation, and (ii) advanced glycation end-product (AGE) /receptor for AGE (RAGE) and palmitic acid promote osteogenic differentiation of VSMC. To understand of the molecular mechanisms of vascular calcification is now under intensive research area.

  14. Calcification of in vitro developed hypertrophic cartilage

    SciTech Connect

    Tacchetti, C.; Quarto, R.; Campanile, G.; Cancedda, R.

    1989-04-01

    We have recently reported that dedifferentiated cells derived from stage 28-30 chick embryo tibiae, when transferred in suspension culture in the presence of ascorbic acid, develop in a tissue closely resembling hypertrophic cartilage. Ultrastructural examination of this in vitro formed cartilage showed numerous matrix vesicles associated with the extracellular matrix. In the present article we report that the in vitro developed hypertrophic cartilage undergoes calcification. We indicate a correlation between the levels of alkaline phosphatase activity and calcium deposition at different times of development. Following the transfer of cells into suspension culture and an initial lag phase, the level of alkaline phosphatase activity rapidly increased. In most experiments the maximum of activity was reached after 5 days of culture. When alkaline phosphatase activity and /sup 45/Ca deposition were measured in the same experiment, we observed that the increase in alkaline phosphatase preceded the deposition of nonwashable calcium deposits in the cartilage.

  15. Intracranial Artery Calcification and Its Clinical Significance

    PubMed Central

    Wu, Xiao Hong; Wang, Li Juan; Wong, Ka Sing

    2016-01-01

    Intracranial arterial calcification (IAC) is an easily identifiable entity on plain head computed tomography scans. Recent studies have found high prevalence rates for IAC worldwide, and this may be associated with ischemic stroke and cognitive decline. Aging, traditional cardiovascular risk factors, and chronic kidney disease have been found to be associated with IAC. The severity of IAC can be assessed using different visual grading scales or various quantitative methods (by measuring volume or intensity). An objective method for assessing IAC using consistent criteria is urgently required to facilitate comparisons between multiple studies involving diverse populations. There is accumulating evidence from clinical studies that IAC could be utilized as an indicator of intracranial atherosclerosis. However, the pathophysiology underlying the potential correlation between IAC and ischemic stroke—through direct arterial stenosis or plaque stability—remains to be determined. More well-designed clinical studies are needed to explore the predictive values of IAC in vascular events and the underlying pathophysiological mechanisms. PMID:27165425

  16. Maximal conservative therapy of calcific uremic ateriolopathy.

    PubMed

    Van Noten, Charlotte; Janssen van Doorn, Karin; Vermander, Evert; Vlayen, Sonja; Verpooten, Gert A; Couttenye, Marie-Madeleine

    2012-07-01

    We present the case of a 61-year- old female patient in long-term hemodialysis who developed calcific uremic arteriolopathy (CUA) upon administration of the oral calcimimetic agent cinacalcet for treatment of secondary hyperparathyroidism. In May 2009, the baseline serum values were parathormone (PTH) 310 pg/ml, calcium 9.1 mg/dl and phosphorous 6.9 mg/dl. Necrotic wounds in the suprapubic fat tissue were successfully treated first, by correcting the calcium phosphorous product; second, through treatment with sodium thiosulfate and third, through intensive wound care with hyperbaric oxygen therapy and vacuum-assisted closure therapy, with no need for parathyroidectomy. Multiple factors have been described to play a role in the development of CUA. Based on the findings of this case, the treatment of CUA should be aimed at correcting different causes simultaneously.

  17. Calcification of multipotent prostate tumor endothelium.

    PubMed

    Dudley, Andrew C; Khan, Zia A; Shih, Shou-Ching; Kang, Soo-Young; Zwaans, Bernadette M M; Bischoff, Joyce; Klagsbrun, Michael

    2008-09-01

    Solid tumors require new blood vessels for growth and metastasis, yet the biology of tumor-specific endothelial cells is poorly understood. We have isolated tumor endothelial cells from mice that spontaneously develop prostate tumors. Clonal populations of tumor endothelial cells expressed hematopoietic and mesenchymal stem cell markers and differentiated to form cartilage- and bone-like tissues. Chondrogenic differentiation was accompanied by an upregulation of cartilage-specific col2a1 and sox9, whereas osteocalcin and the metastasis marker osteopontin were upregulated during osteogenic differentiation. In human and mouse prostate tumors, ectopic vascular calcification was predominately luminal and colocalized with the endothelial marker CD31. Thus, prostate tumor endothelial cells are atypically multipotent and can undergo a mesenchymal-like transition.

  18. Pathological calcifications studied with micro-CT

    NASA Astrophysics Data System (ADS)

    Stock, Stuart R.; Rajamannan, Nalini M.; Brooks, Ellen R.; Langman, Craig B.; Pachman, Lauren M.

    2004-10-01

    The microstructure of pathological biomineral deposits has received relatively little attention, perhaps, in part because of the difficulty preparing samples for microscopy. MicroCT avoids these difficulties, and laboratory microCT results are reviewed for aortic valve calcification (human as well as a rabbit model), for human renal calculi (stones) and for calcinoses formed in juvenile dermatomyositis (JDM). In calcified aortic valves of rabbits, numerical analysis of the data shows statistically significant correlation with diet. In a large kidney stone the pattern of mineralization is clearly revealed and may provide a temporal blueprint for stone growth. In JDM calcified deposits, very different microstructures are observed and may be related to processes unique to this disease.

  19. Pineal and habenula calcification in schizophrenia.

    PubMed

    Sandyk, R

    1992-01-01

    Animal data indicate that melatonin secretion is stimulated by the paraventricular nucleus (PVN) of the hypothalamus and that lesions of the PVN mimic the endocrine effects of pinealectomy. Since the PVN lies adjacent to the third ventricle, I propose that periventricular damage, which is found in schizophrenia and may account for the third ventricular dilatation seen on computed tomographic (CT), may disrupt PVN-pineal interactions and ultimately enhance the process of pineal calcification (PC). To investigate this hypothesis, I conducted CT study on the relationship of PC size to third ventricular width (TVW) in 12 chronic schizophrenic patients (mean age: 33.7 years; SD = 7.3). For comparison, I also studied the relationship of PC size to the ventricular brain ratio and prefrontal cortical atrophy. As predicted, there was a significant correlation between PC size and TVW (r pbi = .61, p < .05), whereas PC was unrelated to the control neuroradiological measures. The findings support the hypothesis that periventricular damage may be involved in the process of PC in schizophrenia and may indirectly implicate damage to the PVN in the mechanisms underlying dysfunction of the pineal gland in schizophrenia. In a second study, I investigated the prevalence of habenular calcification (HAC) on CT in a cohort of 23 chronic schizophrenic-patients (mean age: 31.2 years; SD = 5.95). In this sample HAC was present in 20 patients (87%). Since the prevalence of HAC in a control population of similar age is only 15% these data reveal an almost 6-fold higher prevalence of HAC (X2 = 84.01, p < .0001) in chronic schizophrenia as compared to normal controls. The implications of HAC for the pathophysiology of schizophrenia are discussed in light of the central role of the habenula in the regulation of limbic functions.

  20. Pineal and habenula calcification in schizophrenia.

    PubMed

    Sandyk, R

    1992-01-01

    Animal data indicate that melatonin secretion is stimulated by the paraventricular nucleus (PVN) of the hypothalamus and that lesions of the PVN mimic the endocrine effects of pinealectomy. Since the PVN lies adjacent to the third ventricle, I propose that periventricular damage, which is found in schizophrenia and may account for the third ventricular dilatation seen on computed tomographic (CT), may disrupt PVN-pineal interactions and ultimately enhance the process of pineal calcification (PC). To investigate this hypothesis, I conducted CT study on the relationship of PC size to third ventricular width (TVW) in 12 chronic schizophrenic patients (mean age: 33.7 years; SD = 7.3). For comparison, I also studied the relationship of PC size to the ventricular brain ratio and prefrontal cortical atrophy. As predicted, there was a significant correlation between PC size and TVW (r pbi = .61, p < .05), whereas PC was unrelated to the control neuroradiological measures. The findings support the hypothesis that periventricular damage may be involved in the process of PC in schizophrenia and may indirectly implicate damage to the PVN in the mechanisms underlying dysfunction of the pineal gland in schizophrenia. In a second study, I investigated the prevalence of habenular calcification (HAC) on CT in a cohort of 23 chronic schizophrenic-patients (mean age: 31.2 years; SD = 5.95). In this sample HAC was present in 20 patients (87%). Since the prevalence of HAC in a control population of similar age is only 15% these data reveal an almost 6-fold higher prevalence of HAC (X2 = 84.01, p < .0001) in chronic schizophrenia as compared to normal controls. The implications of HAC for the pathophysiology of schizophrenia are discussed in light of the central role of the habenula in the regulation of limbic functions. PMID:1305634

  1. Screening of Cyanobacterial Species for Calcification

    SciTech Connect

    Brady D. Lee; William A. Apel; Michelle R. Walton

    2004-07-01

    Species of cyanobacteria in the genera Synechococcus and Synechocystis are known to be the catalysts of a phenomenon called "whitings", which is the formation and precipitation of fine-grained CaCO3 particles. Whitings occur when the cyanobacteria fix atmospheric CO2 through the formation of CaCO3 on their cell surfaces, which leads to precipitation to the ocean floor and subsequent entombment in mud. Whitings represent one potential mechanism for CO2 sequestration. Research was performed to determine the ability of various strains of Synechocystis and Synechococcus to calcify when grown in microcosms amended with 2.5 mM HCO3- and 3.4 mM Ca2+. Results indicated that although all strains tested have the ability to calcify, only two Synechococcus species, strains PCC 8806 and PCC 8807, were able to calcify to the extent that a CaCO3 precipitate was formed. Enumeration of the cyanobacterial cultures during testing indicated that cell density did not appear to have a direct effect on calcification. Factors that had the greatest effect on calcification were CO2 removal and subsequent generation of alkaline pH. Whereas cell density was similar for all strains tested, differences in maximum pH were demonstrated. As CO2 was removed, growth medium pH increased and soluble Ca2+ was removed from solution. The largest increases in growth medium pH occurred when CO2 levels dropped below 400 ppmv. Research presented demonstrates that, under the conditions tested, many species of cyanobacteria in the genera Synechocystis and Synechococcus are able to calcify but only two species of Synechococcus were able to calcify to an extent that led to the precipitation of calcium carbonate.

  2. Idiopathic calcification of the seminal vesicles: a rare cause for prostate cancer overstaging.

    PubMed

    Pannek, J; Senge, T

    2001-01-01

    Calcification of the seminal vesicles is a rare phenomenon. We present 2 cases in whom calcification of the seminal vesicles led to preoperative overstaging of prostate cancer. Although idiopathic calcifications are extremely rare, calcifications appear more frequently in diabetic patients. Therefore, knowledge of these formations is essential to prevent overstaging, namely infiltration of the seminal vesicles.

  3. Soft-tissue calcification after subcutaneus emphysema in a neonate

    SciTech Connect

    Naidech, H.J.; Chawla, H.S.

    1982-08-01

    Bilateral, almost symmetric, calcifications of the soft tissues after subcutaneous emphysema have not, to our knowledge, been described. Because of the close clinical and radiographic evaluation in our case, the finding of calcinosis was not a diagnostic problem. Several 1.5 mm computed tomographic (CT) sections of the thorax were scanned and they were confirmatory in showing the distribution of the calcifications. Since subcutaneous emphysema is commonplace, and calcification after it is apparently unknown, the literature was reviewed and an additional cause of soft-tissue calcinosis is presented.

  4. [Study on influence between activated carbon property and immobilized biological activated carbon purification effect].

    PubMed

    Wang, Guang-zhi; Li, Wei-guang; He, Wen-jie; Han, Hong-da; Ding, Chi; Ma, Xiao-na; Qu, Yan-ming

    2006-10-01

    By means of immobilizing five kinds of activated carbon, we studied the influence between the chief activated carbon property items and immobilized bioactivated carbon (IBAC) purification effect with the correlation analysis. The result shows that the activated carbon property items which the correlation coefficient is up 0.7 include molasses, abrasion number, hardness, tannin, uniform coefficient, mean particle diameter and effective particle diameter; the activated carbon property items which the correlation coefficient is up 0.5 include pH, iodine, butane and tetrachloride. In succession, the partial correlation analysis shows that activated carbon property items mostly influencing on IBAC purification effect include molasses, hardness, abrasion number, uniform coefficient, mean particle diameter and effective particle diameter. The causation of these property items bringing influence on IBAC purification is that the activated carbon holes distribution (representative activated carbon property item is molasses) provides inhabitable location and adjust food for the dominance bacteria; the mechanical resist-crash property of activated carbon (representative activated carbon property items: abrasion number and hardness) have influence on the stability of biofilm; and the particle diameter size and distribution of activated carbon (representative activated carbon property items: uniform coefficient, mean particle diameter and effective particle diameter) can directly affect the force of water in IBAC filter bed, which brings influence on the dominance bacteria immobilizing on activated carbon.

  5. Calcification response of a key phytoplankton family to millennial-scale environmental change

    PubMed Central

    McClelland, H. L. O.; Barbarin, N.; Beaufort, L.; Hermoso, M.; Ferretti, P.; Greaves, M.; Rickaby, R. E. M.

    2016-01-01

    Coccolithophores are single-celled photosynthesizing marine algae, responsible for half of the calcification in the surface ocean, and exert a strong influence on the distribution of carbon among global reservoirs, and thus Earth’s climate. Calcification in the surface ocean decreases the buffering capacity of seawater for CO2, whilst photosynthetic carbon fixation has the opposite effect. Experiments in culture have suggested that coccolithophore calcification decreases under high CO2 concentrations ([CO2(aq)]) constituting a negative feedback. However, the extent to which these results are representative of natural populations, and of the response over more than a few hundred generations is unclear. Here we describe and apply a novel rationale for size-normalizing the mass of the calcite plates produced by the most abundant family of coccolithophores, the Noëlaerhabdaceae. On average, ancient populations subjected to coupled gradual increases in [CO2(aq)] and temperature over a few million generations in a natural environment become relatively more highly calcified, implying a positive climatic feedback. We hypothesize that this is the result of selection manifest in natural populations over millennial timescales, so has necessarily eluded laboratory experiments. PMID:27677230

  6. Effect of Calcifications on Breast Ultrasound Shear Wave Elastography: An Investigational Study

    PubMed Central

    Gregory, Adriana; Mehrmohammadi, Mohammad; Denis, Max; Bayat, Mahdi; Stan, Daniela L.; Fatemi, Mostafa; Alizad, Azra

    2015-01-01

    Purpose To investigate the effects of macrocalcifications and clustered microcalcifications associated with benign breast masses on shear wave elastography (SWE). Methods SuperSonic Imagine (SSI) and comb-push ultrasound shear elastography (CUSE) were performed on three sets of phantoms to investigate how calcifications of different sizes and distributions influence measured elasticity. To demonstrate the effect in vivo, three female patients with benign breast masses associated with mammographically-identified calcifications were evaluated by CUSE. Results Apparent maximum elasticity (Emax) estimates resulting from individual macrocalcifications (with diameters of 2mm, 3mm, 5mm, 6mm, 9mm, 11mm, and 15mm) showed values over 50 kPa for all cases, which represents more than 100% increase over background (~21kPa). We considered a 2cm-diameter circular region of interest for all phantom experiments. Mean elasticity (Emean) values varied from 26 kPa to 73 kPa, depending on the macrocalcification size. Highly dense clusters of microcalcifications showed higher Emax values than clusters of microcalcification with low concentrations, but the difference in Emean values was not significant. Conclusions Our results demonstrate that the presence of large isolated macrocalcifications and highly concentrated clusters of microcalcifications can introduce areas with apparent high elasticity in SWE. Considering that benign breast masses normally have significantly lower elasticity values than malignant tumors, such areas with high elasticity appearing due to presence of calcification in benign breast masses may lead to misdiagnosis. PMID:26368939

  7. Coral biomineralization: A focus on intra-skeletal organic matrix and calcification.

    PubMed

    Falini, Giuseppe; Fermani, Simona; Goffredo, Stefano

    2015-10-01

    In the recent years several papers and some reviews have dealt with characterization, localization and influence on the precipitation of calcium carbonate, of the organic matrix from scleractinian corals. In fact, it has been well established that coral calcification is a biological controlled process orchestrated in space and time by the organism also trough the secretion of organic matrix molecules because it has been well established that coral calcification is a biological controlled process, and thus is orchestrated in space and time by the organism also through the secretion of organic matrix molecules. In this review is presented a scientific path on the biomineralization of corals having as focusing point the intra-skeletal organic matrix, the molecules that are associated with mineral (aragonite). The review starts with a an overview on coral tissue, skeleton and tissue skeleton interface, describes the intra-skeletal organic matrix putting attention mainly on the proteins associated to aragonite and finally describes the in vivo and in vitro calcium carbonate precipitation experiments carried out aimed to evaluate the role of the organic matrix. The last paragraph reports studies on the role of the organic matrix in controlling calcification when corals are subject ocean acidification effects. The readers are expected to find a source of inspiration for new studies on the biomineralization of corals that are organic matrix addressed and merge diverse scientific disciplines.

  8. Calcification response of a key phytoplankton family to millennial-scale environmental change

    NASA Astrophysics Data System (ADS)

    McClelland, H. L. O.; Barbarin, N.; Beaufort, L.; Hermoso, M.; Ferretti, P.; Greaves, M.; Rickaby, R. E. M.

    2016-09-01

    Coccolithophores are single-celled photosynthesizing marine algae, responsible for half of the calcification in the surface ocean, and exert a strong influence on the distribution of carbon among global reservoirs, and thus Earth’s climate. Calcification in the surface ocean decreases the buffering capacity of seawater for CO2, whilst photosynthetic carbon fixation has the opposite effect. Experiments in culture have suggested that coccolithophore calcification decreases under high CO2 concentrations ([CO2(aq)]) constituting a negative feedback. However, the extent to which these results are representative of natural populations, and of the response over more than a few hundred generations is unclear. Here we describe and apply a novel rationale for size-normalizing the mass of the calcite plates produced by the most abundant family of coccolithophores, the Noëlaerhabdaceae. On average, ancient populations subjected to coupled gradual increases in [CO2(aq)] and temperature over a few million generations in a natural environment become relatively more highly calcified, implying a positive climatic feedback. We hypothesize that this is the result of selection manifest in natural populations over millennial timescales, so has necessarily eluded laboratory experiments.

  9. In vitro evaluation of anti-calcification and anti-coagulation on sulfonated chitosan and carrageenan surfaces.

    PubMed

    Campelo, Clayton Souza; Lima, Luana Dias; Rebêlo, Luciana Magalhães; Mantovani, Diego; Beppu, Marisa Masumi; Vieira, Rodrigo Silveira

    2016-02-01

    In recent years, great effort has been devoted to the development of biomaterials that come into contact with blood. The surfaces of these materials need to be of suitable mechanical strength, and present anti-thrombogenic and anti-calcification properties. Chitosan is a natural polymer that has attracted attention due to its potential to act as a biomaterial. However, chitosan contains amino groups in its structure that may promote thrombogenesis and calcification. A strategy to reduce these properties constitutes the introduction of sulfonate groups (R-SO3-) in the chitosan chain. Another interesting biopolymer with similar characteristics to those of heparin is carrageenan, which has sulfate groups in its structure. As such, we evaluated “in vitro” calcification and thrombogenic processes on surfaces of pristine and sulfonated chitosan and on polyelectrolyte complexes (PEC) of chitosan and carrageenan. Results indicate that PEC demonstrate significant reductions in calcification and thrombogenic potential, probably due to the presence of sulfonate groups in both the carrageenan and treated chitosan.

  10. Intra-Section Analysis of Human Coronary Arteries Reveals a Potential Role for Micro-Calcifications in Macrophage Recruitment in the Early Stage of Atherosclerosis

    PubMed Central

    Chatrou, Martijn L. L.; Cleutjens, Jack P.; van der Vusse, Ger J.; Roijers, Ruben B.; Mutsaers, Peter H. A.; Schurgers, Leon J.

    2015-01-01

    number of CD68 positive cells were observed in combination with calcification, suggesting a pro-inflammatory effect of micro-calcifications. In vitro, invasion assays revealed chemoattractant properties of cell-culture medium of calcifying vascular smooth muscle cells towards THP-1 cells, which implies pro-inflammatory effect of calcium deposits. Additionally, calcifying hVSMCs revealed a pro-inflammatory profile as compared to non-calcifying hVSMCs. Conclusion Our data indicate that calcification of VSMCs is one of the earliest events in the genesis of atherosclerosis, which strongly correlates with ucMGP staining. Our findings suggest that loss of calcification inhibitors and/or failure of inhibitory capacity is causative for the early precipitation of calcium, with concomitant increased inflammation followed by osteochondrogenic transdifferentiation of VSMCs. PMID:26555788

  11. Dissolution Dominating Calcification Process in Polar Pteropods Close to the Point of Aragonite Undersaturation

    PubMed Central

    Bednaršek, Nina; Tarling, Geraint A.; Bakker, Dorothee C. E.; Fielding, Sophie; Feely, Richard A.

    2014-01-01

    Thecosome pteropods are abundant upper-ocean zooplankton that build aragonite shells. Ocean acidification results in the lowering of aragonite saturation levels in the surface layers, and several incubation studies have shown that rates of calcification in these organisms decrease as a result. This study provides a weight-specific net calcification rate function for thecosome pteropods that includes both rates of dissolution and calcification over a range of plausible future aragonite saturation states (Ωar). We measured gross dissolution in the pteropod Limacina helicina antarctica in the Scotia Sea (Southern Ocean) by incubating living specimens across a range of aragonite saturation states for a maximum of 14 days. Specimens started dissolving almost immediately upon exposure to undersaturated conditions (Ωar∼0.8), losing 1.4% of shell mass per day. The observed rate of gross dissolution was different from that predicted by rate law kinetics of aragonite dissolution, in being higher at Ωar levels slightly above 1 and lower at Ωar levels of between 1 and 0.8. This indicates that shell mass is affected by even transitional levels of saturation, but there is, nevertheless, some partial means of protection for shells when in undersaturated conditions. A function for gross dissolution against Ωar derived from the present observations was compared to a function for gross calcification derived by a different study, and showed that dissolution became the dominating process even at Ωar levels close to 1, with net shell growth ceasing at an Ωar of 1.03. Gross dissolution increasingly dominated net change in shell mass as saturation levels decreased below 1. As well as influencing their viability, such dissolution of pteropod shells in the surface layers will result in slower sinking velocities and decreased carbon and carbonate fluxes to the deep ocean. PMID:25285916

  12. Dissolution dominating calcification process in polar pteropods close to the point of aragonite undersaturation.

    PubMed

    Bednaršek, Nina; Tarling, Geraint A; Bakker, Dorothee C E; Fielding, Sophie; Feely, Richard A

    2014-01-01

    Thecosome pteropods are abundant upper-ocean zooplankton that build aragonite shells. Ocean acidification results in the lowering of aragonite saturation levels in the surface layers, and several incubation studies have shown that rates of calcification in these organisms decrease as a result. This study provides a weight-specific net calcification rate function for thecosome pteropods that includes both rates of dissolution and calcification over a range of plausible future aragonite saturation states (Ω(ar)). We measured gross dissolution in the pteropod Limacina helicina antarctica in the Scotia Sea (Southern Ocean) by incubating living specimens across a range of aragonite saturation states for a maximum of 14 days. Specimens started dissolving almost immediately upon exposure to undersaturated conditions (Ω(ar) ∼ 0.8), losing 1.4% of shell mass per day. The observed rate of gross dissolution was different from that predicted by rate law kinetics of aragonite dissolution, in being higher at Ω(ar) levels slightly above 1 and lower at Ω(ar) levels of between 1 and 0.8. This indicates that shell mass is affected by even transitional levels of saturation, but there is, nevertheless, some partial means of protection for shells when in undersaturated conditions. A function for gross dissolution against Ω(ar) derived from the present observations was compared to a function for gross calcification derived by a different study, and showed that dissolution became the dominating process even at Ω(ar) levels close to 1, with net shell growth ceasing at an Ω(ar) of 1.03. Gross dissolution increasingly dominated net change in shell mass as saturation levels decreased below 1. As well as influencing their viability, such dissolution of pteropod shells in the surface layers will result in slower sinking velocities and decreased carbon and carbonate fluxes to the deep ocean.

  13. Genetics Home Reference: generalized arterial calcification of infancy

    MedlinePlus

    ... It is characterized by abnormal accumulation of the mineral calcium (calcification) in the walls of the blood ... characterized by the accumulation of calcium and other minerals (mineralization) in elastic fibers, which are a component ...

  14. Genetics Home Reference: familial idiopathic basal ganglia calcification

    MedlinePlus

    ... in regulating phosphate levels within the body (phosphate homeostasis) by transporting phosphate across cell membranes. The SLC20A2 ... link familial idiopathic basal ganglia calcification with phosphate homeostasis. Nat Genet. 2012 Feb 12;44(3):254- ...

  15. Calcification of vestibular schwannoma: a case report and literature review.

    PubMed

    Zhang, Yang; Yu, Jinlu; Qu, Limei; Li, Yunqian

    2012-10-02

    Calcification rarely occurs in vestibular schwannoma (VS), and only seven cases of calcified VS have been reported in the literature. Here, we report a 48-year-old man with VS, who had a history of progressive left-sided hearing loss for 3 years. Neurological examination revealed that he had left-sided hearing loss and left cerebellar ataxia. Magnetic resonance imaging and computerized tomography angiography showed a mass with calcification in the left cerebellopontine angle (CPA). The tumor was successfully removed via suboccipital craniotomy, and postoperative histopathology showed that the tumor was a schwannoma. We reviewed seven cases of calcified VS that were previously reported in the literature, and we analyzed and summarized the characteristics of these tumors, including the calcification, texture, and blood supply. We conclude that calcification in VS is associated with its texture and blood supply, and these characteristics affect the surgical removal of the tumor.

  16. Placental calcification: ultrastructural and X-ray microanalytic studies.

    PubMed

    Varma, V A; Kim, K M

    1985-01-01

    Calcification is common in human placentas and is widely recognized as a normal part of maturation and aging of this organ. Eleven human placentas were studied by light and electron microscopy to elucidate the mechanism of placental calcification. Earliest mineral deposits were seen along the trophoblastic basement membrane of the chorionic villi undergoing fibrinoid degeneration. Transmission electron microscopic examination revealed crystalline deposits within small membrane-bound vesicles; the latter appear to be derived from degenerating cells and were particularly numerous within the basement membrane. X-ray microanalysis of these deposits revealed calcium and phosphorus peaks and the pattern of calcium hydroxyapatite was noted by electron diffraction. This pattern of calcification, i.e., precipitation of calcium hydroxyapatite in association with extracellular membrane bound vesicles, is similar to that seen in physiologic and pathologic calcifications of other tissues.

  17. [Calcifications of the prostate: a transrectal echographic study].

    PubMed

    Bock, E; Calugi, V; Stolfi, V; Rossi, P; D'Ascenzo, R; Solivetti, F M

    1989-05-01

    Prostatic lithiasis is a well know phenomenon. It has little clinical significance and is not easily shown by conventional radiography, which has poor sensitivity and specificity. The authors have studied 612 patients with both suprapubic and transrectal US in order to 1) assess US sensitivity and specificity and 2) report the frequency, spatial distribution, number and features of prostatic calcifications with special emphasis on differential diagnosis between prostatic neoplasms and chronic prostatitis. The authors have also studied the relationship between morphology and symptoms and the results agree with those reported in the scanty literature. The authors conclude that the parameters studied are directly related to age, except for a younger group with clear evidence of genital inflammation. The authors emphasize the impossibility to correlate morphology of prostatic calcifications with pathologic conditions: there are no specific symptoms clearly connected with calcification even though the inflammation is often associated with calcifications.

  18. Calcification generates protons for nutrient and bicarbonate uptake

    NASA Astrophysics Data System (ADS)

    McConnaughey, T. A.; Whelan, J. F.

    1997-03-01

    The biosphere's great carbonate deposits, from caliche soils to deep-sea carbonate oozes, precipitate largely as by-products of autotrophic nutrient acquisition physiologies. Protons constitute the critical link: Calcification generates protons, which plants and photosynthetic symbioses use to assimilate bicarbonate and nutrients. A calcium ATPase-based "trans" mechanism underlies most biological calcification. This permits high calcium carbonate supersaturations and rapid carbonate precipitation. The competitive advantages of calcification become especially apparent in light and nutrient-deficient alkaline environments. Calcareous plants often dominate the lower euphotic zone in both the benthos and the plankton. Geographically and seasonally, massive calcification concentrates in nutrient-deficient environments including alkaline soils, coral reefs, cyanobacterial mats and coccolithophorid blooms. Structural and defensive uses for calcareous skeletons are sometimes overrated.

  19. Influence of Carbon on the Electrical Properties of Crustal Rocks

    SciTech Connect

    Mathez, E. A.

    2002-11-19

    The report summarizes work to determine the nature and distribution of carbon on microcracks in crystalline rocks by time-of-flight secondary ion mass spectroscopy. It also summarizes the results of a workshop devoted to investigating how carbon in rocks influences electrical conductivity and whether carbon on fracture surfaces can account for the electrical conductivity structure of the crust.

  20. The influence of microstructure on the mechanical properties of solder

    SciTech Connect

    Morris, J.W. Jr.; Reynolds, H.L.

    1996-06-01

    Solder joints in microelectronics devices consist of low-melting solder compositions that wet and join metal contacts and are, ordinarily, used at high homologous temperatures in the as-solidified condition. Differences in solidification rate and substrate interactions have the consequence that even solder joints of similar compositions exhibit a wide range of microstructures. The variation in microstructure causes a variation in properties; in particular, the high-temperature creep properties that govern much of the mechanical behavior of the solder may differ significantly from joint to joint. The present paper reviews the varieties of microstructure that are found in common solder joints, and describes some of the ways in which microstructural changes affect mechanical properties and joint reliability.

  1. Sodium thiosulfate protects brain in rat model of adenine induced vascular calcification.

    PubMed

    Subhash, N; Sriram, R; Kurian, Gino A

    2015-11-01

    Vascular bed calcification is a common feature of ends stage renal disease that may lead to a complication in cardiovascular and cerebrovascular beds, which is a promoting cause of myocardial infarction, stroke, dementia and aneurysms. Sodium thiosulfate (STS) due to its multiple properties such as antioxidant and calcium chelation has been reported to prevent vascular calcification in uremic rats, without mentioning its impact on cerebral function. Moreover, the previous studies have not explored the effect of STS on the mitochondrial dysfunction, one of the main pathophysiological features associated with the disease and the main site for STS metabolism. The present study addresses this limitation by using a rat model where 0.75% adenine was administered to induce vascular calcification and 400 mg/kg b wt. of STS was given as preventive and curative agent. The blood and urine chemistries along with histopathology of aorta confirms the renal protective effect of STS in two modes of administration. The brain oxidative stress assessment was made through TBARS level, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, found to be in the near normal level. STS administration not only reduced the mitochondrial oxidative stress (measured by TBARS, SOD, GPx and CAT) but also preserved the mitochondrial respiratory enzyme activities (NADH dehydrogenase, Succinate dehydrogenase and Malate dehydrogenase) and its physiology (measured by P/O ratio and RCR). In fact, the protective effect of STS was prominent, when it was administered as a curative agent, where low H2S and high thiosulfate level was observed along with low cystathionine β synthase activity, confirms thiosulfate mediated renal protection. In conclusion, STS when given after induction of calcification is protective to the brain by preserving its mitochondria, compared to the treatment given concomitantly. PMID:26363090

  2. Sodium thiosulfate protects brain in rat model of adenine induced vascular calcification.

    PubMed

    Subhash, N; Sriram, R; Kurian, Gino A

    2015-11-01

    Vascular bed calcification is a common feature of ends stage renal disease that may lead to a complication in cardiovascular and cerebrovascular beds, which is a promoting cause of myocardial infarction, stroke, dementia and aneurysms. Sodium thiosulfate (STS) due to its multiple properties such as antioxidant and calcium chelation has been reported to prevent vascular calcification in uremic rats, without mentioning its impact on cerebral function. Moreover, the previous studies have not explored the effect of STS on the mitochondrial dysfunction, one of the main pathophysiological features associated with the disease and the main site for STS metabolism. The present study addresses this limitation by using a rat model where 0.75% adenine was administered to induce vascular calcification and 400 mg/kg b wt. of STS was given as preventive and curative agent. The blood and urine chemistries along with histopathology of aorta confirms the renal protective effect of STS in two modes of administration. The brain oxidative stress assessment was made through TBARS level, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, found to be in the near normal level. STS administration not only reduced the mitochondrial oxidative stress (measured by TBARS, SOD, GPx and CAT) but also preserved the mitochondrial respiratory enzyme activities (NADH dehydrogenase, Succinate dehydrogenase and Malate dehydrogenase) and its physiology (measured by P/O ratio and RCR). In fact, the protective effect of STS was prominent, when it was administered as a curative agent, where low H2S and high thiosulfate level was observed along with low cystathionine β synthase activity, confirms thiosulfate mediated renal protection. In conclusion, STS when given after induction of calcification is protective to the brain by preserving its mitochondria, compared to the treatment given concomitantly.

  3. Influence of microstructure on the properties of resistance spot welds

    SciTech Connect

    Santella, M.L.; Babu, S.S.; Riemer, B.W.; Feng, Z.

    1998-11-01

    An integrated model approach was proposed for relating resistance welding parameters to weldment properties. A key element of the approach is microstructure modeling. It was demonstrated that existing process models and microstructure models can be used to determine the spatial distribution of microstructures and properties in resistance spot welds of a plain carbon steel. It was also shown by finite element analysis that the existence of microstructure gradients in the welds is expected to reduce their ability to support shear loads by about 50%.

  4. A Review of the Effect of Diet on Cardiovascular Calcification

    PubMed Central

    Nicoll, Rachel; Howard, John McLaren; Henein, Michael Y.

    2015-01-01

    Cardiovascular (CV) calcification is known as sub-clinical atherosclerosis and is recognised as a predictor of CV events and mortality. As yet there is no treatment for CV calcification and conventional CV risk factors are not consistently correlated, leaving clinicians uncertain as to optimum management for these patients. For this reason, a review of studies investigating diet and serum levels of macro- and micronutrients was carried out. Although there were few human studies of macronutrients, nevertheless transfats and simple sugars should be avoided, while long chain ω-3 fats from oily fish may be protective. Among the micronutrients, an intake of 800 μg/day calcium was beneficial in those without renal disease or hyperparathyroidism, while inorganic phosphorus from food preservatives and colas may induce calcification. A high intake of magnesium (≥380 mg/day) and phylloquinone (500 μg/day) proved protective, as did a serum 25(OH)D concentration of ≥75 nmol/L. Although oxidative damage appears to be a cause of CV calcification, the antioxidant vitamins proved to be largely ineffective, while supplementation of α-tocopherol may induce calcification. Nevertheless other antioxidant compounds (epigallocatechin gallate from green tea and resveratrol from red wine) were protective. Finally, a homocysteine concentration >12 µmol/L was predictive of CV calcification, although a plasma folate concentration of >39.4 nmol/L could both lower homocysteine and protect against calcification. In terms of a dietary programme, these recommendations indicate avoiding sugar and the transfats and preservatives found in processed foods and drinks and adopting a diet high in oily fish and vegetables. The micronutrients magnesium and vitamin K may be worthy of further investigation as a treatment option for CV calcification. PMID:25906474

  5. [Neuroimaging findings in cerebroretinal microangiopathy with calcifications and cysts].

    PubMed

    Herrera, Diego Alberto; Vargas, Sergio Alberto; Montoya, Claudia

    2014-01-01

    Cerebroretinal microangiopathy with calcifications and cysts is a rare condition characterized by brain, retinal and bone anomalies, as well as a predisposition to gastrointestinal bleeding. There are few reported cases of this condition in adults, among whom the incidence is low. Neuroimaging findings are characteristic, with bilateral calcifications, leukoencephalopathy and intracranial cysts. The purpose of this article was to do a literature survey and illustrate two cases diagnosed with the aid of neuroimaging. PMID:24967922

  6. Acid-Base Balance in Uremic Rats with Vascular Calcification

    PubMed Central

    Peralta-Ramírez, Alan; Raya, Ana Isabel; Pineda, Carmen; Rodríguez, Mariano; Aguilera-Tejero, Escolástico; López, Ignacio

    2014-01-01

    Background/Aims Vascular calcification (VC), a major complication in humans and animals with chronic kidney disease (CKD), is influenced by changes in acid-base balance. The purpose of this study was to describe the acid-base balance in uremic rats with VC and to correlate the parameters that define acid-base equilibrium with VC. Methods Twenty-two rats with CKD induced by 5/6 nephrectomy (5/6 Nx) and 10 nonuremic control rats were studied. Results The 5/6 Nx rats showed extensive VC as evidenced by a high aortic calcium (9.2 ± 1.7 mg/g of tissue) and phosphorus (20.6 ± 4.9 mg/g of tissue) content. Uremic rats had an increased pH level (7.57 ± 0.03) as a consequence of both respiratory (PaCO2 = 28.4 ± 2.1 mm Hg) and, to a lesser degree, metabolic (base excess = 4.1 ± 1 mmol/l) derangements. A high positive correlation between both anion gap (AG) and strong ion difference (SID) with aortic calcium (AG: r = 0.604, p = 0.02; SID: r = 0.647, p = 0.01) and with aortic phosphorus (AG: r = 0.684, p = 0.007; SID: r = 0.785, p = 0.01) was detected. Conclusions In an experimental model of uremic rats, VC showed high positive correlation with AG and SID. PMID:25177336

  7. Dense calcification in a GH-secreting pituitary macroadenoma

    PubMed Central

    Ibrahim, Ramez; Kalhan, Atul; Lammie, Alistair; Kotonya, Christine; Nannapanenni, Ravindra; Rees, Aled

    2014-01-01

    Summary A 30-year-old female presented with a history of secondary amenorrhoea, acromegalic features and progressive visual deterioration. She had elevated serum IGF1 levels and unsuppressed GH levels after an oral glucose tolerance test. Magnetic resonance imaging revealed a heterogeneously enhancing space-occupying lesion with atypical extensive calcification within the sellar and suprasellar areas. Owing to the extent of calcification, the tumour was a surgical challenge. Postoperatively, there was clinical, radiological and biochemical evidence of residual disease, which required treatment with a somatostatin analogue and radiotherapy. Mutational analysis of the aryl hydrocarbon receptor-interacting protein (AIP) gene was negative. This case confirms the relatively rare occurrence of calcification within a pituitary macroadenoma and its associated management problems. The presentation, biochemical, radiological and pathological findings are discussed in the context of the relevant literature. Learning points Calcification of pituitary tumours is relatively rare.Recognising calcification in pituitary adenomas on preoperative imaging is important in surgical decision-making.Gross total resection can be difficult to achieve in the presence of extensive calcification and dictates further management and follow-up to achieve disease control. PMID:24683483

  8. Computed tomography study of pineal calcification in schizophrenia.

    PubMed

    Bersani, G; Garavini, A; Taddei, I; Tanfani, G; Nordio, M; Pancheri, P

    1999-06-01

    Computed tomography studies concerning pineal calcification (PC) in schizophrenia have been conducted mainly by one author who correlated this calcification with several aspects of the illness. On the basis of these findings the aim of the present study was to analyze size and incidence of pineal gland calcification by CT in schizophrenics and healthy controls, and to verify the relationship between pineal calcification and age, and the possible correlation with psychopathologic variables. Pineal calcification was measured on CT scans of 87 schizophrenics and 46 controls divided into seven age subgroups of five years each. No significant differences in PC incidence and mean size between patients and controls were observed as far as the entire group was considered. PC size correlated with age both in schizophrenics and controls. We found a higher incidence of PC in schizophrenics in the age subgroup of 21-25 years, and a negative correlation with positive symptoms of schizophrenia in the overall group. These findings could suggest a premature calcific process in schizophrenics and a probable association with 'non-paranoid' aspects of the illness. Nevertheless the potential role of this process possibly related to some aspects of the altered neurodevelopment in schizophrenia is still unclear. PMID:10572342

  9. Ocean acidification reduces growth and calcification in a marine dinoflagellate.

    PubMed

    Van de Waal, Dedmer B; John, Uwe; Ziveri, Patrizia; Reichart, Gert-Jan; Hoins, Mirja; Sluijs, Appy; Rost, Björn

    2013-01-01

    Ocean acidification is considered a major threat to marine ecosystems and may particularly affect calcifying organisms such as corals, foraminifera and coccolithophores. Here we investigate the impact of elevated pCO2 and lowered pH on growth and calcification in the common calcareous dinoflagellate Thoracosphaera heimii. We observe a substantial reduction in growth rate, calcification and cyst stability of T. heimii under elevated pCO2. Furthermore, transcriptomic analyses reveal CO2 sensitive regulation of many genes, particularly those being associated to inorganic carbon acquisition and calcification. Stable carbon isotope fractionation for organic carbon production increased with increasing pCO2 whereas it decreased for calcification, which suggests interdependence between both processes. We also found a strong effect of pCO2 on the stable oxygen isotopic composition of calcite, in line with earlier observations concerning another T. heimii strain. The observed changes in stable oxygen and carbon isotope composition of T. heimii cysts may provide an ideal tool for reconstructing past seawater carbonate chemistry, and ultimately past pCO2. Although the function of calcification in T. heimii remains unresolved, this trait likely plays an important role in the ecological and evolutionary success of this species. Acting on calcification as well as growth, ocean acidification may therefore impose a great threat for T. heimii.

  10. ADVANCE: Study to Evaluate Cinacalcet Plus Low Dose Vitamin D on Vascular Calcification in Subjects With Chronic Kidney Disease Receiving Hemodialysis

    ClinicalTrials.gov

    2014-07-14

    Chronic Kidney Disease; End Stage Renal Disease; Coronary Artery Calcification; Vascular Calcification; Calcification; Cardiovascular Disease; Chronic Renal Failure; Hyperparathyroidism; Kidney Disease; Nephrology; Secondary Hyperparathyroidism

  11. The influence of powder properties on the imbibation rate.

    PubMed

    Hellborg, D; Bergenståhl, B; Trägårdh, C

    2012-05-01

    Mixing of powders into liquids is a common unit operation. Mixing can be divided into several steps, imbibation of the powder into the liquid being the first. Under some circumstances, such as when the powder has poor wetting properties, imbibation can be the rate-determining step. The effects of different powder properties on the imbibation rate were evaluated using an experimental imbibation model based on the imbibing process employed in an industrial powder-in-liquid mixer. A multivariate analysis of the results suggests that bulk density and capillary penetration rate, and to some extent cohesivity, play an important role in determining the powder imbibation rate. The results also suggest that the capillary penetration rate is increasing on a large particle radius, slow solubilisation of the particles and a low ability of the particles to generate viscosity. PMID:22244301

  12. The influence of grain size on the mechanical properties ofsteel

    SciTech Connect

    Morris Jr., J.W.

    2001-05-01

    Many of the important mechanical properties of steel, including yield strength and hardness, the ductile-brittle transition temperature and susceptibility to environmental embrittlement can be improved by refining the grain size. The improvement can often be quantified in a constitutive relation that is an appropriate variant on the familiar Hall-Petch relation: the quantitative improvement in properties varies with d{sup -1/2}, where d is the grain size. Nonetheless, there is considerable uncertainty regarding the detailed mechanism of the grain size effect, and appropriate definition of ''grain size''. Each particular mechanism of strengthening and fracture suggests its own appropriate definition of the ''effective grain size'', and how it may be best controlled.

  13. Influence of hydrogen bonds and temperature on dielectric properties

    NASA Astrophysics Data System (ADS)

    Ortiz de Urbina, Jordi; Sesé, Gemma

    2016-07-01

    Dielectric properties are evaluated by means of molecular dynamics simulations on two model systems made up of dipolar molecules. One of them mimics methanol, whereas the other differs from the former only in the ability to form hydrogen bonds. Static dielectric properties such as the permittivity and the Kirkwood factor are evaluated, and results are analyzed by considering the distribution of relative orientations between molecular dipoles. Dipole moment-time correlation functions are also evaluated. The relevance of contributions associated with autocorrelations of molecular dipoles and with cross-correlations between dipoles belonging to different molecules has been investigated. For methanol, the Debye approximation for the overall dipole moment correlation function is not valid at room temperature. The model applies when hydrogen bonds are suppressed, but it fails upon cooling the nonassociated liquid. Important differences between relaxation times associated with dipole auto- versus cross-correlations as well as their relative relevance are at the root of the Debye model breakdown.

  14. Influence of hydrogen bonds and temperature on dielectric properties.

    PubMed

    Ortiz de Urbina, Jordi; Sesé, Gemma

    2016-07-01

    Dielectric properties are evaluated by means of molecular dynamics simulations on two model systems made up of dipolar molecules. One of them mimics methanol, whereas the other differs from the former only in the ability to form hydrogen bonds. Static dielectric properties such as the permittivity and the Kirkwood factor are evaluated, and results are analyzed by considering the distribution of relative orientations between molecular dipoles. Dipole moment-time correlation functions are also evaluated. The relevance of contributions associated with autocorrelations of molecular dipoles and with cross-correlations between dipoles belonging to different molecules has been investigated. For methanol, the Debye approximation for the overall dipole moment correlation function is not valid at room temperature. The model applies when hydrogen bonds are suppressed, but it fails upon cooling the nonassociated liquid. Important differences between relaxation times associated with dipole auto- versus cross-correlations as well as their relative relevance are at the root of the Debye model breakdown. PMID:27575177

  15. Process design of press hardening with gradient material property influence

    SciTech Connect

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-05-04

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  16. The influence of additives on rheological properties of limestone slurry

    NASA Astrophysics Data System (ADS)

    Jaworska, B.; Bartosik, A.

    2014-08-01

    Limestone slurry appears in the lime production process as the result of rinsing the processed material. It consists of particles with diameter smaller than 2 mm and the water that is a carrier of solid fraction. Slurry is directed to the settling tank, where the solid phase sediments and the excess water through the transfer system is recovered for re-circulation. Collected at the bottom of the tank sludge is deposited in a landfill located on the premises. Rheological properties of limestone slurry hinder its further free transport in the pipeline due to generated flow resistance. To improve this state of affairs, chemical treatment of drilling fluid, could be applied, of which the main task is to give the slurry properties suitable for the conditions encountered in hydrotransport. This treatment consists of applying chemical additives to slurry in sufficient quantity. Such additives are called as deflocculants or thinners or dispersants, and are chemical compounds which added to aqueous solution are intended to push away suspended particles from each other. The paper presents the results of research allowing reduction of shear stress in limestone slurry. Results demonstrate rheological properties of limestone slurry with and without the addition of modified substances which causes decrease of slurry viscosity, and as a consequence slurry shear stress for adopted shear rate. Achieving the desired effects increases the degree of dispersion of the solid phase suspended in the carrier liquid and improving its ability to smooth flow with decreased friction.

  17. Influence of sedimentary environments on mechanical properties of clastic rocks

    NASA Astrophysics Data System (ADS)

    Meng, Zhaoping; Zhang, Jincai; Peng, Suping

    2006-10-01

    The sedimentary environments are the intrinsic factor controlling the mechanical properties of clastic rocks. Examining the relationship between rock sedimentary environments and rock mechanical properties gives a better understanding of rock deformation and failure mechanisms. In this study, more than 55 samples in coal measures were taken from seven different lithologic formations in eastern China. Using the optical microscope the sedimentary characteristics, such as components of clastic rocks and sizes of clastic grains were quantitatively tested and analyzed. The corresponding mechanical parameters were tested using the servo-controlled testing system. Different lithologic attributes in the sedimentary rocks sampled different stress-strain behaviors and failure characteristics under different confining pressures, mainly due to different compositions and textures. Results demonstrate that clastic rocks have the linear best-fit for Mohr-Coulomb failure criterion. The elastic moduli in clastic rocks are highly dependent upon confining pressures, unlike hard rocks. The envelope lines of the mechanical properties versus the contents of quartz, detritus of the grain diameter of more than 0.03 mm, and grain size in clastic rocks are given. The compressive strength or elastic modulus and the grain diameter have a non-monotonic relation and demonstrate the “grain-diameter softening” effect.

  18. Influence of dispersion medium on properties of complex lithium greases

    SciTech Connect

    Bulgak, V.B.; Cherednichenko, G.I.; Sokolova, T.G.; Voznyuk, F.Z.

    1984-03-01

    This article investigates the properties of complex lithium (cLi) greases prepared by thickening various dispersion media, differing in hydrocarbon composition, with cLi soap (10% by weight). Distillate and residual oils produced in the USSR were used as the dispersion media. It is determined that the viscosity level of the dispersion medium does not determine the properties of the cLi greases. The presence of aromatic hydrocarbons in the distillate oils, as the content of aromatics is increased, tends to increase the viscosity-strength characteristics, increase the colloidal stability (lower the oil bleeding), reduce the heat-hardening, and give lower values of the viscosity-temperature characteristics of the greases. The quality of cLi greases based on distillate oils depends to a considerable degree on the hydrocarbon group composition of the oil and on the hydrocarbon structure. The greases based on residual oils have better rheological properties and serviceability at high temperatures than the greases based on distillate oils. It is recommended that residual oils be used as the dispersion medium for cLi greases operating at high temperatures. Includes 3 tables.

  19. Influence of carbon nanotubes on mechanical properties and structure of rigid polyurethane foam

    NASA Astrophysics Data System (ADS)

    Ciecierska, E.; Jurczyk-Kowalska, M.; Bazarnik, P.; Kulesza, M.; Lewandowska, M.; Kowalski, M.; Krauze, S.

    2014-08-01

    In this work, the influence of carbon nanotubes addition on foam structure and mechanical properties of rigid polyurethane foam/nanotube composites was investigated. Scanning electron microscopy was performed to reveal the foam porous structure and distribution of carbon nanotubes. To determine the mechanical properties, three point bending tests were carried out.

  20. The Fabric of Thought: Priming Tactile Properties during Reading Influences Direct Tactile Perception

    ERIC Educational Resources Information Center

    Brunye, Tad T.; Walters, Eliza K.; Ditman, Tali; Gagnon, Stephanie A.; Mahoney, Caroline R.; Taylor, Holly A.

    2012-01-01

    The present studies examined whether implied tactile properties during language comprehension influence subsequent direct tactile perception, and the specificity of any such effects. Participants read sentences that implicitly conveyed information regarding tactile properties (e.g., "Grace tried on a pair of thick corduroy pants while shopping")…

  1. Factors Influencing the Dielectric Properties of Agricultural Products and Food Materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dielectric properties of materials are defined, and the major factors that influence these properties of agricultural and food materials, namely, frequency of the applied radio-frequency and microwave electric fields, water content, temperature, and density of the materials are discussed on the bas...

  2. Coronary artery calcification in renal transplant recipients.

    PubMed

    Rosas, Sylvia E; Mensah, Korlei; Weinstein, Rachel B; Bellamy, Scarlett L; Rader, Daniel J

    2005-08-01

    Cardiovascular disease is the leading cause of mortality in renal transplant recipients. Although renal transplant recipients frequently undergo cardiac functional tests prior to surgery, coronary atherosclerosis can remain undetected. Coronary artery calcification (CAC), an early marker of atherosclerosis can be quantified using EBCT. The purpose of this study was to determine the extent and characteristics of CAC at the time of renal transplantation. We evaluated 79 consecutive incident asymptomatic renal transplant recipients. Patients were mostly White (62%), male (54%) and had a deceased donor renal transplant (61%). The mean age was 47 (12.1) years. Sixty-five percentage of subjects had CAC. The mean CAC score was 331.5 (562.4) with a median of 43.3. Older age, presence of diabetes, not having a preemptive transplant, deceased donor transplantation and hypercholesterolemia were significantly associated with presence of CAC univariately. Median CAC scores were significantly increased in subjects with diabetes (127.8 vs. 28.9, p=0.05), exposed to dialysis (102.9 vs. 3.7, p<0.001) and deceased donor recipients (169.7 vs. 7.5, p=0.02). Using multiple logistic regression, age and time on dialysis were significantly associated with the presence of CAC at the time of transplant. In summary, CAC is prevalent in patients undergoing kidney transplant. CAC may be a method to identify renal transplant recipients at increased risk for future cardiovascular events. PMID:15996243

  3. Vascular calcification and renal bone disorders.

    PubMed

    Lu, Kuo-Cheng; Wu, Chia-Chao; Yen, Jen-Fen; Liu, Wen-Chih

    2014-01-01

    At the early stage of chronic kidney disease (CKD), the systemic mineral metabolism and bone composition start to change. This alteration is known as chronic kidney disease-mineral bone disorder (CKD-MBD). It is well known that the bone turnover disorder is the most common complication of CKD-MBD. Besides, CKD patients usually suffer from vascular calcification (VC), which is highly associated with mortality. Many factors regulate the VC mechanism, which include imbalances in serum calcium and phosphate, systemic inflammation, RANK/RANKL/OPG triad, aldosterone, microRNAs, osteogenic transdifferentiation, and effects of vitamins. These factors have roles in both promoting and inhibiting VC. Patients with CKD usually have bone turnover problems. Patients with high bone turnover have increase of calcium and phosphate release from the bone. By contrast, when bone turnover is low, serum calcium and phosphate levels are frequently maintained at high levels because the reservoir functions of bone decrease. Both of these conditions will increase the possibility of VC. In addition, the calcified vessel may secrete FGF23 and Wnt inhibitors such as sclerostin, DKK-1, and secreted frizzled-related protein to prevent further VC. However, all of them may fight back the inhibition of bone formation resulting in fragile bone. There are several ways to treat VC depending on the bone turnover status of the individual. The main goals of therapy are to maintain normal bone turnover and protect against VC. PMID:25136676

  4. Intracranial Calcifications and Hemorrhages: Characterization with Quantitative Susceptibility Mapping

    PubMed Central

    Chen, Weiwei; Zhu, Wenzhen; Kovanlikaya, IIhami; Kovanlikaya, Arzu; Liu, Tian; Wang, Shuai; Salustri, Carlo

    2014-01-01

    Purpose To compare gradient-echo (GRE) phase magnetic resonance (MR) imaging and quantitative susceptibility mapping (QSM) in the detection of intracranial calcifications and hemorrhages. Materials and Methods This retrospective study was approved by the institutional review board. Thirty-eight patients (24 male, 14 female; mean age, 33 years ± 16 [standard deviation]) with intracranial calcifications and/or hemorrhages diagnosed on the basis of computed tomography (CT), MR imaging (interval between examinations, 1.78 days ± 1.31), and clinical information were selected. GRE and QSM images were reconstructed from the same GRE data. Two experienced neuroradiologists independently identified the calcifications and hemorrhages on the QSM and GRE phase images in two randomized sessions. Sensitivity, specificity, and interobserver agreement were computed and compared with the McNemar test and k coefficients. Calcification loads and volumes were measured to gauge intermodality correlations with CT. Results A total of 156 lesions were detected: 62 hemorrhages, 89 calcifications, and five mixed lesions containing both hemorrhage and calcification. Most of these lesions (146 of 151 lesions, 96.7%) had a dominant sign on QSM images suggestive of a specific diagnosis of hemorrhage or calcium, whereas half of these lesions (76 of 151, 50.3%) were heterogeneous on GRE phase images and thus were difficult to characterize. Averaged over the two independent observers for detecting hemorrhages, QSM achieved a sensitivity of 89.5% and a specificity of 94.5%, which were significantly higher than those at GRE phase imaging (71% and 80%, respectively; P < .05 for both readers). In the identification of calcifications, QSM achieved a sensitivity of 80.5%, which was marginally higher than that with GRE phase imaging (71%; P = .08 and .10 for the two readers), and a specificity of 93.5%, which was significantly higher than that with GRE phase imaging (76.5%; P < .05 for both readers

  5. Computer aided breast calcification auto-detection in cone beam breast CT

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohua; Ning, Ruola; Liu, Jiangkun

    2010-03-01

    In Cone Beam Breast CT (CBBCT), breast calcifications have higher intensities than the surrounding tissues. Without the superposition of breast structures, the three-dimensional distribution of the calcifications can be revealed. In this research, based on the fact that calcifications have higher contrast, a local thresholding and a histogram thresholding were used to select candidate calcification areas. Six features were extracted from each candidate calcification: average foreground CT number value, foreground CT number standard deviation, average background CT number value, background CT number standard deviation, foreground-background contrast, and average edge gradient. To reduce the false positive candidate calcifications, a feed-forward back propagation artificial neural network was designed. The artificial neural network was trained with the radiologists confirmed calcifications and used as classifier in the calcification auto-detection task. In the preliminary experiments, 90% of the calcifications in the testing data sets were detected correctly with an average of 10 false positives per data set.

  6. Influence of octacalcium phosphate coating on osteoinductive properties of biomaterials.

    PubMed

    Habibovic, P; van der Valk, C M; van Blitterswijk, C A; De Groot, K; Meijer, G

    2004-04-01

    In this study, we investigated the influence of octacalcium phosphate (OCP) coating on osteoinductive behaviour of the biomaterials. Porous titanium alloy (Ti6Al4V), hydroxyapatite (HA), biphasic calcium phosphate (BCP) and polyethylene glyco terephtalate/polybuthylene terephtalate (PEGT-PBT) copolymer, all uncoated and coated with biomimetically produced OCP, were implanted in back muscles of 10 goats for 6 and 12 weeks. Uncoated Ti6Al4Vand HA did not show any bone formation after intramuscular implantation. All OCP coated implants, except PEGT-PBT, did induce bone in the soft tissue. The reason for the non-inductive behaviour of the copolymer is probably its softness, that makes it impossible to maintain its porous shape after implantation. Both uncoated and OCP coated BCP induced bone. However, the amount of animals in which the bone was induced was higher in the coated BCP implants in comparison to the uncoated ones. Osteoinductive potential of biomaterials is influenced by various material characteristics, such as chemical composition, crystallinity, macro- and microstructure. OCP coating has a positive effect on osteoinductivity of the biomaterials. The combination of the advantages of biomimetic coating method above traditional methods, and a good osteoinductivity of OCP coating that is produced by using this method, opens new possibilities for designing more advanced orthopaedic implants. PMID:15332602

  7. Laser cutting: influence on morphological and physicochemical properties of polyhydroxybutyrate.

    PubMed

    Lootz, D; Behrend, D; Kramer, S; Freier, T; Haubold, A; Benkiesser, G; Schmitz, K P; Becher, B

    2001-09-01

    Polyhydroxybutyrate (PHB) is a biocompatible and resorbable implant material. For these reasons, it has been used for the fabrication of temporary stents, bone plates, nails and screws (Peng et al. Biomaterials 1996;17:685). In some cases, the brittle mechanical properties of PHB homopolymer limit its application. A typical plasticizer, triethylcitrate (TEC), was used to overcome such limitations by making the material more pliable. In the past few years, CO2-laser cutting of PHB was used in the manufacturing of small medical devices such as stents. Embrittlement of plasticized PHB tubes has been observed, after laser machining. Consequently, the physicochemical and morphological properties of laser-processed surfaces and cut edges of plasticized polymer samples were examined to determine the extent of changes in polymer properties as a result of laser machining. These studies included determination of the depth of the laser-induced heat affected zone by polariscopy of thin polymer sections. Molecular weight changes and changes in the TEC content as a function of distance from the laser-cut edge were determined. In a preliminary test, the cellular response to the processed material was investigated by cell culture study of L929 mouse fibroblasts on laser-machined surfaces. The heat-affected zone was readily classified into four different regions with a total depth of about 60 to 100 microm (Klamp, Master Thesis, University of Rostock, 1998). These results correspond well with the chemical analysis and molecular weight measurements. Furthermore, it was found that cells grew preferentially on the laser-machined area. These findings have significant implications for the manufacture of medical implants from PHB by laser machining.

  8. Influence of network properties on routing within a catchment

    NASA Astrophysics Data System (ADS)

    Åkesson (Née Gustafsson), A.; Wörman, A.; Lindstrom, G.

    2009-12-01

    This study concerns how river network characteristics (topology and geomorpholpogy) and their stage dependency can be used as means to parameterize hydrological compartment models, such as e.g. HBV. By increasing the coupling to physical properties, the performance of these models versus data is expected to be improved - especially regarding hydrological extremes. By the use of particle-tracking routing routines, distributions of flow distances and flow times through a catchment are expressed as functions of channel morphology, topology and stage. By analyzing these effects separately and together, we conclude that the transit time for water is strongly non-linearly related to stage and correlated with geomorphology as well as network topology. A primary effect is due to the change in hydraulics in parts of the river network were flooding occurs during high flows. The impact of network effects and stage on water transit times in different subcatchments are analysed. The preliminary results show that topological properties are highly responsible for the appearance of the response functions. The controlling factors are mapped in different catchments, on different areal scale and during different conditions (stages). A case study is also reported for Ronne catchment, Sweden (about 1900 km2). By relating the distributions of transit times to generalised properties of the sub-catchments, we can theoretically transfer information from one catchment to another. A later phase of this research will be to make a similar study in River Ljusnan (20 000 km2) to conclude how these generalised channel network and hydraulic characteristics can be used to bridge temporal and spatial scales in hydrology. By the increased use of GIS applications (and the continuous augmentation of this type of data), generalised channel network data of this kind can easily be obtained, even for remote catchments of little previous hydrological monitoring.

  9. Influence of chemical processing on the imaging properties of microlenses

    NASA Astrophysics Data System (ADS)

    Vasiljević, Darko; Murić, Branka; Pantelić, Dejan; Panić, Bratimir

    2009-07-01

    Microlenses are produced by irradiation of a layer of tot'hema and eosin sensitized gelatin (TESG) by using a laser beam (Nd:YAG 2nd harmonic; 532 nm). All the microlenses obtained are concave with a parabolic profile. After the production, the microlenses are chemically processed with various concentrations of alum. The following imaging properties of microlenses were calculated and analyzed: the root mean square (rms) wavefront aberration, the geometric encircled energy and the spot diagram. The microlenses with higher concentrations of alum in solution had a greater effective focal length and better image quality. The microlenses chemically processed with 10% alum solution had near-diffraction-limited performance.

  10. Influence of combustion conditions and coal properties on physical properties of fly ash generated from pulverized coal combustion

    SciTech Connect

    Hiromi Shirai; Hirofumi Tsuji; Michitaka Ikeda; Toshinobu Kotsuji

    2009-07-15

    To develop combustion technology for upgrading the quality of fly ash, the influences of the coal properties, such as the size of pulverized coal particles and the two-stage combustion ratio during the combustion, on the fly ash properties were investigated using our test furnace. The particle size, density, specific surface area (obtained by the Blaine method), and shape of fly ash particles of seven types of coal were measured. It was confirmed that the size of pulverized coal particles affects the size of the ash particles. Regarding the coal properties, the fuel ratio affected the ash particle size distribution. The density and shape of the ash particles strongly depended on their ash size. Our results indicated that the shape of the ash particles and the concentration of unburned carbon affected the specific surface area. The influence of the two-stage combustion ratio was limited. 8 refs., 13 figs., 3 tabs.

  11. Mechanical Properties of Mineralized Collagen Fibrils As Influenced By Demineralization

    SciTech Connect

    Balooch, M.; Habelitz, S.; Kinney, J.H.; Marshall, S.J.; Marshall, G.W.

    2009-05-11

    Dentin and bone derive their mechanical properties from a complex arrangement of collagen type-I fibrils reinforced with nanocrystalline apatite mineral in extra- and intrafibrillar compartments. While mechanical properties have been determined for the bulk of the mineralized tissue, information on the mechanics of the individual fibril is limited. Here, atomic force microscopy was used on individual collagen fibrils to study structural and mechanical changes during acid etching. The characteristic 67 nm periodicity of gap zones was not observed on the mineralized fibril, but became apparent and increasingly pronounced with continuous demineralization. AFM-nanoindentation showed a decrease in modulus from 1.5 GPa to 50 MPa during acid etching of individual collagen fibrils and revealed that the modulus profile followed the axial periodicity. The nanomechanical data, Raman spectroscopy and SAXS support the hypothesis that intrafibrillar mineral etches at a substantially slower rate than the extrafibrillar mineral. These findings are relevant for understanding the biomechanics and design principles of calcified tissues derived from collagen matrices.

  12. Influence of biofilms on transport properties in porous media

    NASA Astrophysics Data System (ADS)

    Davit, Y.

    2015-12-01

    Microbial activity and biofilm growth in porous media can drastically modify transport properties such as permeability, longitudinal and transverse dispersion or effective reaction rates. Understanding these effects has proven to be a considerable challenge. Advances in this field have been hindered by the difficulty of modeling and visualizing these multi-phase non-linear effects across a broad range of spatial and temporal scales. To address these issues, we are developing a strategy that combines imaging techniques based on x-ray micro-tomography with homogenization of pore-scale transport equations. Here, we review recent progress in x-ray imaging of biofilms in porous media, with a particular focus on the contrast agents that are used to differentiate between the fluid and biofilm phases. We further show how the 3D distribution of the different phases can be used to extract specific information about the biofilm and how effective properties can be calculated via the resolution of closure problems. These closure problems are obtained using the method of volume averaging and must be adapted to the problem of interest. In hydrological systems, we show that a generic formulation for reactive solute transport is based on a domain decomposition approach at the micro-scale yielding macro-scale models reminiscent of multi-rate mass transfer approaches.

  13. Properties that Influence the Specific Surface Areas of Carbon Nanotubes and Nanofibers

    PubMed Central

    BIRCH, M. EILEEN; RUDA-EBERENZ, TONI A.; CHAI, MING; ANDREWS, RONNEE; HATFIELD, RANDAL L.

    2015-01-01

    Commercially available carbon nanotubes and nanofibers were analyzed to examine possible relationships between their Brunauer–Emmett–Teller specific surface areas (SSAs) and their physical and chemical properties. Properties found to influence surface area were number of walls/diameter, impurities, and surface functionalization with hydroxyl and carboxyl groups. Characterization by electron microscopy, energy-dispersive X-ray spectrometry, thermogravimetric analysis, and elemental analysis indicates that SSA can provide insight on carbon nanomaterials properties, which can differ vastly depending on synthesis parameters and post-production treatments. In this study, how different properties may influence surface area is discussed. The materials examined have a wide range of surface areas. The measured surface areas differed from product specifications, to varying degrees, and between similar products. Findings emphasize the multiple factors that influence surface area and mark its utility in carbon nanomaterial characterization, a prerequisite to understanding their potential applications and toxicities. Implications for occupational monitoring are discussed. PMID:24029925

  14. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Extracellular matrix tenascin-X in calcific aortic valves].

    PubMed

    Matsumoto, Ken-ichi

    2015-05-01

    We previously disclosed a novel extracellular matrix tenascin-X (TNX) , the largest member of the tenascin family. So far, we have made efforts to elucidate the roles of TNX. TNX is involved in collagen deposition, collagen fibrillogenesis, and modulation of collagen stiffness. Homozygous mutations in TNXB, the gene encoding TNX, cause a classic-type Ehlers-Danlos syndrome (EDS) , a heritable connective tissue disorder, whereas haploinsufficiency of TNXB and heterozygous mutations in TNXB are associated with hypermobility-type EDS. Recently, we performed proteomic analyses of calcific aortic valves (CAVs) compared with relatively adjacent normal tissues to understand the underlying molecular mechanisms of dystrophic valvular calcification. Interestingly, we found that TNX was the protein with the greatest decrease in expression among the differentially expressed proteins and that expression levels of proteins modulating collagen structure and function, such as type I collagen and decorin, were also decreased in CAVs. In this review, I will discuss about the decreased level of collagen due to the reduction of expression levels of proteins that play regulatory roles in collagen functions such as fibril organization and fibrillogenesis in CAVs. PMID:25926574

  15. Shunt tube calcification as a late complication of ventriculoperitoneal shunting

    PubMed Central

    Salim, Abubakr Darrag; Elzain, Mohammed Awad; Mohamed, Haddab Ahmed; Ibrahim Zayan, Baha Eldin Mohamed

    2015-01-01

    Shunt calcification is a rare complication of ventriculoperitoneal shunting that occurs years later after the initial operation this condition is rarely reported in literature. Two patients with shunt calcifications were described. The first patient was 17-year-old lady who had congenital hydrocephalus and shunted in the early infancy, she was presented recently complaining of itching of the skin along the shunt track and limitation of neck movement. The patient was then operated with removal of the old peritoneal catheter and replacing it with a new one. The second patient was 17-year-old boy originally was a case of posterior fossa pilocytic astrocytoma associated with obstructive hydrocephalus, he was operated with both shunting for the hydrocephalus and tumor removal, 6 years later he presented with shunt exposure. Calcification of the shunt tube was discovered intraoperatively upon shunt removal. Shunt calcification has been observed mainly in barium-impregnated catheters. Introducing plain silicone-coated shunt tubing may reduce the rate of this condition. The usual complaints of the patients suffering from this condition are pain in the neck and chest wall along the shunt pathway and limitation of the neck movement due to shunt tube tethering, but features of shunt dysfunction and skin irritation above the shunt may be present. In this review, plain X-ray and operative findings showed that the most extensive calcification is present in the neck, where the catheters were subject to heavy mechanical stress. Disturbed calcium and phosphate metabolisms may be involved in this condition. Shunt calcification is a rare condition that occurs due to material aging presenting with features of shunt tethering, dysfunction or overlying skin irritation. Plain X-ray is needed to detect calcification while shunt removal, replacement or endoscopic third ventriculostomy may carry solution for this condition. PMID:26396620

  16. The association between abdominal body composition and vascular calcification.

    PubMed

    Jensky, Nicole E; Criqui, Michael H; Wright, C Michael; Wassel, Christina L; Alcaraz, John E; Allison, Matthew A

    2011-12-01

    Subclinical cardiovascular disease (CVD) may be associated with both adipose and skeletal muscle tissues in the abdomen. Accordingly, we examined whether subcutaneous, intermuscular, and visceral adipose tissue, as well as abdominal lean muscle, were associated with the presence and extent of vascular calcification in multiple vascular beds. Three hundred and ninety four patients (58.1% men) underwent electron beam computed tomography (EBCT) scans as part of routine health maintenance screening. The coronary and carotid calcium scores were analyzed at the time of the scan, whereas the other calcium scores, as well as the body composition analyses, were analyzed retrospectively. Mean age was 55.2 ± 11.1 years and BMI was 26.9 ± 4.2. The prevalence of any calcification in the carotids, coronaries, thoracic aorta, abdominal aorta, and iliacs was 30.1, 60.1, 39.8, 55.7, and 56.8%, respectively. Compared to those with calcification in different vascular beds, those without vascular calcification generally had significantly more lean muscle and less adipose tissue. In separate multivariable logistic models, a 1 s.d. increment in the ratio of abdominal and visceral fat to total area of each corresponding compartments was significantly associated with an increased odds for the presence of thoracic aortic calcium (odds ratio (OR) = 1.6, 1.5, respectively; P = 0.01 for both). Conversely, increases in abdominal lean muscle were associated with significantly decreased odds of thoracic aortic calcification (OR = 0.34; P ≤ 0.01). A similar pattern of associations existed among the other vascular beds. Also, the association between lean muscle and vascular calcification was independent of visceral adipose tissue. In conclusion, adipose tissue was positively and lean body mass inversely associated with prevalent aortic calcification. PMID:21475146

  17. The dark and bright side of atherosclerotic calcification.

    PubMed

    Pugliese, Giuseppe; Iacobini, Carla; Blasetti Fantauzzi, Claudia; Menini, Stefano

    2015-02-01

    Vascular calcification is an unfavorable event in the natural history of atherosclerosis that predicts cardiovascular morbidity and mortality. However, increasing evidence suggests that different calcification patterns are associated with different or even opposite histopathological and clinical features, reflecting the dual relationship between inflammation and calcification. In fact, initial calcium deposition in response to pro-inflammatory stimuli results in the formation of spotty or granular calcification ("microcalcification"), which induces further inflammation. This vicious cycle favors plaque rupture, unless an adaptive response prevails, with blunting of inflammation and survival of vascular smooth muscle cells (VSMCs). VSMCs promote fibrosis and also undergo osteogenic transdifferentiation, with formation of homogeneous or sheet-like calcification ("macrocalcification"), that stabilizes the plaque by serving as a barrier towards inflammation. Unfortunately, little is known about the molecular mechanisms regulating this adaptive response. The advanced glycation/lipoxidation endproducts (AGEs/ALEs) have been shown to promote vascular calcification and atherosclerosis. Recent evidence suggests that two AGE/ALE receptors, RAGE and galectin-3, modulate in divergent ways, not only inflammation, but also vascular osteogenesis, by favoring "microcalcification" and "macrocalcification", respectively. Galectin-3 seems essential for VSMC transdifferentiation into osteoblast-like cells via direct modulation of the WNT-β-catenin signaling, thus driving formation of "macrocalcification", whereas RAGE favors deposition of "microcalcification" by promoting and perpetuating inflammation and by counteracting the osteoblastogenic effect of galectin-3. Further studies are required to understand the molecular mechanisms regulating transition from "microcalcification" to "macrocalcification", thus allowing to design therapeutic strategies which favor this adaptive process

  18. Influence of Fatty acids on foaming properties of cider.

    PubMed

    Margolles Cabrales, Inmaculada; Arias Abrodo, Pilar; Blanco-Gomis, Domingo

    2003-10-01

    Seventy-seven ciders from four consecutive harvests, which were produced at industrial scale by cider-makers from the region of Asturias (northern Spain), were analyzed to evaluate their foam capacity. The Bikerman method for the evaluation of foaming characteristics was adapted to ciders. In foaming, there are two parameters, foam formation and foam stability, which are found to be related to each other. To determine the relationship between fatty acid content and foaming properties of cider, the multivariate analysis technique of canonical correlation analysis was applied. Foam stability is positively related to the content of caprylic acid. Foam height is positively related to linolenic, pentadecanoic, and palmitic acid and negatively related to stearic and linoleic acid. PMID:14518961

  19. Predicting molybdenum toxicity to higher plants: influence of soil properties.

    PubMed

    McGrath, S P; Micó, C; Curdy, R; Zhao, F J

    2010-10-01

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED50) of Mo in different soils, explaining>65% of the variance in ED50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations.

  20. Influence of porosity on thermophysical properties of a composite

    SciTech Connect

    Grishaeva, N. Yu. Ljukshin, B. A. Bochkareva, S. A.; Strukov, Yu. S.

    2015-10-27

    In many modern information systems, the heat generated during the operation of electronic devices is usually dissipated by heat-conductive pads between the casing of the respective equipment and a massive base (platform). For newly developed pads, the promising materials are composites on the basis of various types of silicone rubber. At the same time, during the production of the pads without a vacuum setup, the material can contain air bubbles, which causes the porosity potentially negative for the thermal properties of the material. This work studies the thermal conductivity depending on the degree of silicone matrix filling by copper particles, introduced to improve thermal conductivity, and by air bubbles that are considered as reinforcing inclusions.

  1. Influence of porosity on thermophysical properties of a composite

    NASA Astrophysics Data System (ADS)

    Grishaeva, N. Yu.; Ljukshin, B. A.; Strukov, Yu. S.; Bochkareva, S. A.

    2015-10-01

    In many modern information systems, the heat generated during the operation of electronic devices is usually dissipated by heat-conductive pads between the casing of the respective equipment and a massive base (platform). For newly developed pads, the promising materials are composites on the basis of various types of silicone rubber. At the same time, during the production of the pads without a vacuum setup, the material can contain air bubbles, which causes the porosity potentially negative for the thermal properties of the material. This work studies the thermal conductivity depending on the degree of silicone matrix filling by copper particles, introduced to improve thermal conductivity, and by air bubbles that are considered as reinforcing inclusions.

  2. Influence of hydroxyl substitution on flavanone antioxidants properties.

    PubMed

    Masek, Anna; Chrzescijanska, Ewa; Latos, Malgorzata; Zaborski, Marian

    2017-01-15

    The aim of our study was to determine the effect of the position of the hydroxyl group on the antioxidant properties of flavonoid derivatives. For this purpose, we performed electrochemical analysis and quantum-mechanical calculations to describe the mechanisms of electrochemical oxidation, and we selected the two methods of ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), which allowed us to determine the ability to scavenge free radicals. On the basis of the research, we found that the derivatives of flavonoids, which have a hydroxyl group substituted at the R-3 position on the C ring, have outstanding antioxidant activity. Flavone, which had an OH group substituted at the R-6 and R-7 position on the ring A, showed similar antioxidant activity to flavone without -OH groups in the structure and slightly higher activity than the di-substituted flavone on the ring A. PMID:27542504

  3. Chemical modifications of graphene and their influence on properties of polyurethane composites: a review

    NASA Astrophysics Data System (ADS)

    Włodarczyk, D.; Urban, M.; Strankowski, M.

    2016-10-01

    Polyurethane composites are materials of great interest nowadays due to their wide range of available forms and applications in industry. Controlling and achieving unique properties via matrix modifications and addition of various specific nanofillers seems be one of the key elements to success. The purpose of this work is to briefly present some examples of graphene nanoderivatives, their syntheses, properties and influence on polyurethane matrix after application. Structural, mechanical and electrical properties of graphene nanofillers were analyzed before and after implementation into polymer matrices. Additionally properties of obtained composites were considered in the context of shape memory. The first chapter presents methods of synthesizing carbon nanofillers and some structure investigations via x-ray Diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy. The second part discusses influence of graphene modifications on polymer structure and changes in thermomechanical properties via stress-strain tests and Thermogravimetry (TG).

  4. Influence of the processed sunflower oil on the cement properties

    NASA Astrophysics Data System (ADS)

    Fleysher, A. U.; Tokarchuk, V. V.; Sviderskiy, V. A.

    2015-01-01

    Used oils (vegetable oil, animal oil, engine oil, etc.), which are essentially industrial wastes, have found application as secondary raw materials in some braches of industry. In particular, the only well-known and commonly-used way of utilizing wastes of vegetable oils is to apply them as raw materials in the production of biodiesel. The goal of the present study is to develop a conceptually new way of vegetable oil wastes utilization in the building industry. The test admixture D-148 was obtained from the processing of wastes of sunflower oil and it mainly consists of fatty acid diethanolamide. The test admixture was added to the cement system for the purpose of studying its influence on water demand, flowability, setting times, compressive strength and moisture adsorption. The test admixture D-148 at the optimal content 0. 2 weight % causes 10% decrease in water demand, 1.7 time increase in flowability (namely spread diameter), 23% increase in grade strength and 34% decrease in moisture adsorption. The results of the present investigation make it possible to consider the final product of the waste sunflower oil processing as multifunctional plasticizing-waterproofing admixture.

  5. Processing and nanostructure influences on mechanical properties of thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Schmidt, Robert David

    Thermoelectric (TE) materials are materials that can generate an electric current from a thermal gradient, with possible service in recovery of waste heat such as engine exhaust. Significant progress has been made in improving TE conversion efficiency, typically reported according to the figure of merit, ZT, with several recent papers publishing ZT values above 2. Furthermore, cost reductions may be made by the use of lower cost elements such as Mg, Si, Sn, Pb, Se and S in TE materials, while achieving ZT values between 1.3 and 1.8. To be used in a device, the thermoelectric material must be able to withstand the applied thermal and mechanical forces without failure. However, these materials are brittle, with low fracture toughness typically less than 1.5 MPa-m1/2, and often less than 0.5 MPa-m1/2. For comparison, window glass is approximately 0.75 MPa-m1/2. They have been optimized with nanoprecipitates, nanoparticles, doping, alterations in stoichiometry, powder processing and other techniques, all of which may alter the mechanical properties. In this study, the effect of SiC nanoparticle additions in Mg2Si, SnTe and Ag nanoparticle additions in the skutterudite Ba0.3Co 4Sb12 on the elastic moduli, hardness and fracture toughness are measured. Large changes (˜20%) in the elastic moduli in SnTe 1+x as a function of x at 0 and 0.016 are shown. The effect on mechanical properties of doping and precipitates of CdS or ZnS in a PbS or PbSe matrix have been reported. Changes in sintering behavior of the skutterudite with the Ag nanoparticle additions were explored. Possible liquid phase sintering, with associated benefits in lower processing temperature, faster densification and lower cost, has been shown. A technique has been proposed for determining additional liquid phase sintering aids in other TE materials. The effects of porosity, grain size, powder processing method, and sintering method were explored with YbAl3 and Ba0.3Co4Sb 12, with the porosity dependence of

  6. Influence of moisture content on physical properties of minor millets.

    PubMed

    Balasubramanian, S; Viswanathan, R

    2010-06-01

    Physical properties including 1000 kernel weight, bulk density, true density, porosity, angle of repose, coefficient of static friction, coefficient of internal friction and grain hardness were determined for foxtail millet, little millet, kodo millet, common millet, barnyard millet and finger millet in the moisture content range of 11.1 to 25% db. Thousand kernel weight increased from 2.3 to 6.1 g and angle of repose increased from 25.0 to 38.2°. Bulk density decreased from 868.1 to 477.1 kg/m(3) and true density from 1988.7 to 884.4 kg/m(3) for all minor millets when observed in the moisture range of 11.1 to 25%. Porosity decreased from 63.7 to 32.5%. Coefficient of static friction of minor millets against mild steel surface increased from 0.253 to 0.728 and coefficient of internal friction was in the range of 1.217 and 1.964 in the moisture range studied. Grain hardness decreased from 30.7 to 12.4 for all minor millets when moisture content was increased from 11.1 to 25% db. PMID:23572637

  7. Lahar Properties and Propagation: The Influence of Bulking and Debulking

    NASA Astrophysics Data System (ADS)

    Fagents, S. A.; Baloga, S. M.

    2005-12-01

    Construction of physics-based models lahar flow processes is complicated by the need to account for varying topography, solid mass fractions and complex rheologic behaviors. The incorporation and loss of material (sediments or water) during the advance of a lahar can significantly influence the advance rate, mobility, rheology, and inundation limits of the flow, and therefore has consequences for destructive potential. We have developed a theoretical treatment based on the conservation of flow volume and mass to describe the effects of such processes on flow characteristics. We apply our model to a common scenario of lahar generation and evolution; the formation of an initially dilute flow by catastrophic breaching or ejection of a volcanic summit crater lake, followed by bulking due to incorporation of substrate materials, and later debulking due to sediment deposition. The key features of this model are time-dependence and the inclusion of two terms describing the influx or efflux of sediments to or from the flow, at a rate proportional to the volumetric flow rate. For lahars triggered by crater-lake water, we derive the time-evolution of flow behavior for comparison with the well-documented lahars of Mt. Ruapehu, New Zealand. Our model produces qualitatively realistic behavior with respect to flow depth and density profiles, downstream hydrograph evolution, erosional and depositional regimes, and transformations between streamflow, hyperconcentrated flow and debris flow conditions. However, there is a need for further testing with a suite of field data sets. These include detailed pre- and post-event topographic cross-sectional and longitudinal transects of potential lahar pathways, as well as observations on active lahars (i.e., discharge hydrographs at multiple downflow localities, high-water marks reflecting the passage of the peak stage, and observations of the flow erosional/depositional and rheologic/density regimes). The resulting calibration will allow

  8. The mechanism of vascular calcification – a systematic review

    PubMed Central

    Karwowski, Wojciech; Naumnik, Beata; Szczepański, Marek; Myśliwiec, Michał

    2012-01-01

    Summary Calcification of vessels reduces their elasticity, affecting hemodynamic parameters of the cardiovascular system. The development of arterial hypertension, cardiac hypertrophy, ischemic heart disease or peripheral arterial disease significantly increases mortality in patients over 60 years of age. Stage of advancement and the extent of accumulation of calcium deposits in vessel walls are key risk factors of ischemic events. Vascular calcification is an active and complex process that involves numerous mechanisms responsible for calcium depositions in arterial walls. They lead to increase in arterial stiffness and in pulse wave velocity, which in turn increases cardiovascular disease morbidity and mortality. In-depth study and thorough understanding of vascular calcification mechanisms may be crucial for establishing an effective vasculoprotective therapy. The aim of this study was to present a comprehensive survey of current state-of-the-art research into the impact of metabolic and hormonal disorders on development of vascular calcification. Due to strong resemblance to the processes occurring in bone tissue, drugs used for osteoporosis treatment (calcitriol, estradiol, bisphosphonates) may interfere with the processes occurring in the vessel wall. On the other hand, drugs used to treat cardiovascular problems (statins, angiotensin convertase inhibitors, warfarin, heparins) may have an effect on bone tissue metabolism. Efforts to optimally control calcium and phosphate concentrations are also beneficial for patients with end-stage renal disease, for whom vessel calcification remains a major problem. PMID:22207127

  9. Gaussian weighted projection for visualization of cardiac calcification

    NASA Astrophysics Data System (ADS)

    Chen, Xiang; Li, Ke; Gilkeson, Robert; Fei, Baowei

    2008-03-01

    At our institution, we are using dual-energy digital radiography (DEDR) as a cost-effective screening tool for the detection of cardiac calcification. We are evaluating DEDR using CT as the gold standard. We are developing image projection methods for the generation of digitally reconstructed radiography (DRR) from CT image volumes. Traditional visualization methods include maximum intensity projection (MIP) and average-based projection (AVG) that have difficulty to show cardiac calcification. Furthermore, MIP can over estimate the calcified lesion as it displays the maximum intensity along the projection rays regardless of tissue types. For AVG projection, the calcified tissue is usually overlapped with bone, lung and mediastinum. In order to improve the visualization of calcification on DRR images, we developed a Gaussian-weighted projection method for this particular application. We assume that the CT intensity values of calcified tissues have a Gaussian distribution. We then use multiple Gaussian functions to fit the intensity histogram. Based on the mean and standard deviation parameters, we incorporate a Gaussian weighted function into the perspective projection and display the calcification exclusively. Our digital and physical phantom studies show that the new projection method can display tissues selectively. In addition, clinical images show that the Gaussian-weighted projection method better visualizes cardiac calcification than either the AVG or MIP method and can be used to evaluate DEDR as a screening tool for the detection of coronary artery diseases.

  10. Epilepsy, occipital calcifications, and oligosymptomatic celiac disease in childhood.

    PubMed

    Arroyo, Hugo A; De Rosa, Susana; Ruggieri, Victor; de Dávila, María T G; Fejerman, Natalio

    2002-11-01

    The association of epilepsy, occipital calcifications, and celiac disease has been recognized as a distinct syndrome. The objective of this study was to present the clinical, electrophysiologic, and neuroradiologic features in a series of patients with this syndrome. Thirty-two patients with the constellation of epilepsy, occipital calcifications, and celiac disease were identified in our epilepsy clinic. The mean age was 11 years and the mean length of follow-up was 7.4 years. The 1990 criteria of the European Society of Pediatric Gastroenterology and Nutrition were used to diagnose celiac disease. The Kruskal-Wallis statistics test was employed with a signficance of P < .05. Thirty-one patients had partial seizures, 21 of them with symptoms related to the occipital lobe. In most patients, the epilepsy was controlled or the seizures were sporadic. Three developed severe epilepsy. Occipital calcifications were present in all cases. Computed tomography in 7 patients showed hypodense areas in the white matter around calcifications, which decreased or disappeared after a period of gluten-free diet in 3 patients. A favorable outcome of epilepsy was detected in patients with the earliest dietary therapy. This study presents the largest series of children with this syndrome outside Italy. White-matter hypodensities surrounding calcifications are rarely reported. A prompt diagnosis of celiac disease might improve the evolution of the epilepsy and may improve cognitive status. PMID:12585717

  11. Inflammatory, metabolic, and genetic mechanisms of vascular calcification.

    PubMed

    Demer, Linda L; Tintut, Yin

    2014-04-01

    This review centers on updating the active research area of vascular calcification. This pathology underlies substantial cardiovascular morbidity and mortality, through adverse mechanical effects on vascular compliance, vasomotion, and, most likely, plaque stability. Biomineralization is a complex, regulated process occurring widely throughout nature. Decades ago, its presence in the vasculature was considered a mere curiosity and an unregulated, dystrophic process that does not involve biological mechanisms. Although it remains controversial whether the process has any adaptive value or past evolutionary advantage, substantial advances have been made in understanding the biological mechanisms driving the process. Different types of calcific vasculopathy, such as inflammatory versus metabolic, have parallel mechanisms in skeletal bone calcification, such as intramembranous and endochondral ossification. Recent work has identified important regulatory roles for inflammation, oxidized lipids, elastin, alkaline phosphatase, osteoprogenitor cells, matrix γ-carboxyglutamic acid protein, transglutaminase, osteoclastic regulatory factors, phosphate regulatory hormones and receptors, apoptosis, prelamin A, autophagy, and microvesicles or microparticles similar to the matrix vesicles of skeletal bone. Recent work has uncovered fascinating interactions between matrix γ-carboxyglutamic acid protein, vitamin K, warfarin, and transport proteins. And, lastly, recent breakthroughs in inherited forms of calcific vasculopathy have identified the genes responsible as well as an unexpected overlap of phenotypes. Until recently, vascular calcification was considered a purely degenerative, unregulated process. Since then, investigative groups around the world have identified a wide range of causative mechanisms and regulatory pathways, and some of the recent developments are highlighted in this review.

  12. Intracranial Cortical Calcifications in a Focal Epilepsy Patient with Pseudohypoparathyroidism.

    PubMed

    Kim, Ye Sel; Park, Jihyung; Park, Yoonkyung; Hwang, KyoungJin; Koo, Dae Lim; Kim, Daeyoung; Seo, Dae-Won

    2016-06-01

    Patients with chronic parathyroid dysfunction often have intracranial calcification in deep gray matter (GM) and subcortical white matter (WM) of their brain. Some of them are also epilepsy patients. Although cortical etiologies are main cause of epileptic seizure, cortical calcification has not been reported in these patients. We report a newly diagnosed focal epilepsy patient whose brain magnetic resonance imaging revealed intracranial calcifications in cortical as well as subcortical areas. Blood lab revealed that he had hypocalcemia due to pseudohypoparathyroidism. Video EEG monitoring revealed the ictal EEG mainly consist of polymorphic delta to theta waves with maximum at right temporal area followed by background attenuation and muscle artifacts. The interictal EEG showed multiple focal spike-wave discharges. After given oral calcium and calcitriol supplement, his calcium and phosphorous level normalized and he remains seizure free. This is the first case to show cortical calcification in a patient with pseudohypoparathyroidism. Cortical calcification could be an important measure of seizure burden in these patients and thus sophisticated imaging protocols should be used to visualize the extent of calcium deposits. PMID:27390678

  13. Intracranial Cortical Calcifications in a Focal Epilepsy Patient with Pseudohypoparathyroidism

    PubMed Central

    Kim, Ye Sel; Park, Jihyung; Park, Yoonkyung; Hwang, KyoungJin; Koo, Dae Lim; Kim, Daeyoung; Seo, Dae-Won

    2016-01-01

    Patients with chronic parathyroid dysfunction often have intracranial calcification in deep gray matter (GM) and subcortical white matter (WM) of their brain. Some of them are also epilepsy patients. Although cortical etiologies are main cause of epileptic seizure, cortical calcification has not been reported in these patients. We report a newly diagnosed focal epilepsy patient whose brain magnetic resonance imaging revealed intracranial calcifications in cortical as well as subcortical areas. Blood lab revealed that he had hypocalcemia due to pseudohypoparathyroidism. Video EEG monitoring revealed the ictal EEG mainly consist of polymorphic delta to theta waves with maximum at right temporal area followed by background attenuation and muscle artifacts. The interictal EEG showed multiple focal spike-wave discharges. After given oral calcium and calcitriol supplement, his calcium and phosphorous level normalized and he remains seizure free. This is the first case to show cortical calcification in a patient with pseudohypoparathyroidism. Cortical calcification could be an important measure of seizure burden in these patients and thus sophisticated imaging protocols should be used to visualize the extent of calcium deposits. PMID:27390678

  14. Organic Carbon Influences on Soil Particle Density and Rheological Properties

    SciTech Connect

    Blanco-Canqui, H; Lal, Rattan; Post, W M.; Izaurralde, R Cesar C.; Shipitalo, M. J.

    2006-07-01

    Soil particle density (rs) is not routinely measured and is assumed to range between 2.60 and 2.70 Mgm23 or to be a constant (2.65 Mgm23) when estimating essential properties such as porosity, and volumetric water and air relations. Values of rs for the same soil may, however, differ significantly from the standard range due to management induced changes in soil organic carbon (SOC) concentrations. We quantified the rs and Atterberg limits of a Rayne silt loam for five long-term (.22 yr) moldboard-plowed continuous corn (Zea mays L.; MP), no-till continuous corn (NT), no-till continuous corn with beef cattle manure (NTm), pasture, and forest systems.We also assessed the relationships of SOC concentration with rs and the Atterberg limits and the impact of rs on soil porosity. Mean rs across NT, NTm, and pasture (2.35 Mg m23) was |7% lower than that for MP in the 0- to 10-cm soil depth (2.52 Mg m23, P , 0.01). Forest had the lowest rs of all soils (1.79 Mg m23). The NTm caused a greater reduction in rs and a greater increase in SOC concentration, liquid limit (LL), plastic limit (PL), and plasticity index (PI) than NT. Surface soils under MP had the highest rs and rb and the lowest SOC concentration, LL, PL, and PI. The SOC concentration was correlated negatively with rs (r 2 5 0.75) and positively with Atterberg limits (r 2 . 0.64) at .20-cm depth. Estimates of soil porosity for NT, NTm, and pasture using the constant rs overestimated the ''true'' porosity by 12% relative to that using the measured rs.

  15. The Influence of Nanopore Dimensions on the Electrochemical Properties of Nanopore Arrays Studied by Impedance Spectroscopy

    PubMed Central

    Kant, Krishna; Priest, Craig; Shapter, Joe G.; Losic, Dusan

    2014-01-01

    The understanding of the electrochemical properties of nanopores is the key factor for better understanding their performance and applications for nanopore-based sensing devices. In this study, the influence of pore dimensions of nanoporous alumina (NPA) membranes prepared by an anodization process and their electrochemical properties as a sensing platform using impedance spectroscopy was explored. NPA with four different pore diameters (25 nm, 45 nm and 65 nm) and lengths (5 μm to 20 μm) was used and their electrochemical properties were explored using different concentration of electrolyte solution (NaCl) ranging from 1 to 100 μM. Our results show that the impedance and resistance of nanopores are influenced by the concentration and ion species of electrolytes, while the capacitance is independent of them. It was found that nanopore diameters also have a significant influence on impedance due to changes in the thickness of the double layer inside the pores. PMID:25393785

  16. Quality and safety aspects of reusable plastic food packaging materials: influence of reuse on intrinsic properties.

    PubMed

    Jetten, J; de, Kruijf N

    2002-01-01

    The aim of the project was to develop a comprehensive package of quality assurance criteria for use by the industry and by regulatory authorities to ensure the quality and safety-in-use (sensory, microbiological and chemical safety) of reused plastics for food packaging. The paper describes the investigations into potential adulteration effects by reuse on the intrinsic properties of plastics in more detail. The plastic articles investigated were bottles of polyethylene terephthalate (PET) or polycarbonate (PC) and vending cups of polypropylene (PP). The influence of repeated use on the migration of plastic constituents, degradation products of plastic additives, barrier properties and surface characteristics were investigated. The overall conclusion was that the investigated intrinsic properties of the refillable articles were not significantly influenced by repeated use. Only the hydrophobicity of the refillable PC and PP articles seemed to be influenced by repeated washing. PC bottles washed 15 times were significantly less hydrophobic than unwashed bottles.

  17. Quality and safety aspects of reusable plastic food packaging materials: influence of reuse on intrinsic properties.

    PubMed

    Jetten, J; de, Kruijf N

    2002-01-01

    The aim of the project was to develop a comprehensive package of quality assurance criteria for use by the industry and by regulatory authorities to ensure the quality and safety-in-use (sensory, microbiological and chemical safety) of reused plastics for food packaging. The paper describes the investigations into potential adulteration effects by reuse on the intrinsic properties of plastics in more detail. The plastic articles investigated were bottles of polyethylene terephthalate (PET) or polycarbonate (PC) and vending cups of polypropylene (PP). The influence of repeated use on the migration of plastic constituents, degradation products of plastic additives, barrier properties and surface characteristics were investigated. The overall conclusion was that the investigated intrinsic properties of the refillable articles were not significantly influenced by repeated use. Only the hydrophobicity of the refillable PC and PP articles seemed to be influenced by repeated washing. PC bottles washed 15 times were significantly less hydrophobic than unwashed bottles. PMID:11811768

  18. Decreased calcification in the Southern Ocean over the satellite record

    NASA Astrophysics Data System (ADS)

    Freeman, Natalie M.; Lovenduski, Nicole S.

    2015-03-01

    Widespread ocean acidification is occurring as the ocean absorbs anthropogenic carbon dioxide from the atmosphere, threatening marine ecosystems, particularly the calcifying plankton that provide the base of the marine food chain and play a key role within the global carbon cycle. We use satellite estimates of particulate inorganic carbon (PIC), surface chlorophyll, and sea surface temperature to provide a first estimate of changing calcification rates throughout the Southern Ocean. From 1998 to 2014 we observe a 4% basin-wide reduction in summer calcification, with ˜9% reductions in large regions (˜1 × 106 km2) of the Pacific and Indian sectors. Southern Ocean trends are spatially heterogeneous and primarily driven by changes in PIC concentration (suspended calcite), which has declined by ˜24% in these regions. The observed decline in Southern Ocean calcification and PIC is suggestive of large-scale changes in the carbon cycle and provides insight into organism vulnerability in a changing environment.

  19. Coconut Atrium: Transmural Calcification of the Entire Left Atrium

    PubMed Central

    Campo, Carlos Del; Weinstein, Paul; Kunnelis, Constantine; DiStefano, Peter; Ebers, Gloria M.

    2000-01-01

    Massive calcification of the left atrium usually spares the interatrial septum, which provides a cleavage plane for surgical access to the mitral valve. Endoatriectomy with mitral valve replacement is the currently accepted corrective procedure because it affords maximum exposure while decreasing the risk of embolization and intraoperative hemorrhage. We describe a case in which the entire left atrium, including the septum, was thickly calcified and resembled a coconut shell. This condition prevented surgical correction of severe mitral stenosis. To our knowledge, this is the most severe case of left atrial calcification yet reported in the literature. Although it is not possible to establish preoperatively that the atrium is completely calcified and impossible to incise, when predisposing factors and evidence of complete transmural calcification are present, the surgeon should be aware of this possibility and should weigh carefully the decision to operate. PMID:10830629

  20. Declining coral calcification on the Great Barrier Reef.

    PubMed

    De'ath, Glenn; Lough, Janice M; Fabricius, Katharina E

    2009-01-01

    Reef-building corals are under increasing physiological stress from a changing climate and ocean absorption of increasing atmospheric carbon dioxide. We investigated 328 colonies of massive Porites corals from 69 reefs of the Great Barrier Reef (GBR) in Australia. Their skeletal records show that throughout the GBR, calcification has declined by 14.2% since 1990, predominantly because extension (linear growth) has declined by 13.3%. The data suggest that such a severe and sudden decline in calcification is unprecedented in at least the past 400 years. Calcification increases linearly with increasing large-scale sea surface temperature but responds nonlinearly to annual temperature anomalies. The causes of the decline remain unknown; however, this study suggests that increasing temperature stress and a declining saturation state of seawater aragonite may be diminishing the ability of GBR corals to deposit calcium carbonate.

  1. Atypical localizations of calcific deposits in the shoulder

    PubMed Central

    Vinanti, G.B.; Pavan, D.; Rossato, A.; Biz, Carlo

    2015-01-01

    Introduction Calcific tendinopathies of the shoulder are due to inflammation around deposits of calcium within periarticular tendineal structures. Presentation of cases We present three cases of atypical localization of calcium deposits in the shoulder. All of the cases have been treated with arthroscopic excision, followed by post-operative rehabilitation, regaining excellent results. Patients were evaluated 6 months after surgery using the Visual Analogue Scale (VAS), the Simple Shoulder Test (SST) and the UCLA modified shoulder rating. Discussion Calcific tendinopathy is a self-limiting condition or is successfully treated with conservative therapy especially during the early phases of the pathology. If conservative measures fail, removal of calcium deposits is recommended. Arthroscopic management showed good results in our three cases. Conclusion We suggest that arthroscopic treatment of calcific tendonitis guarantees good results even when calcium deposits are in atypical locations. PMID:25884610

  2. Impact of elevated CO2 on shellfish calcification

    NASA Astrophysics Data System (ADS)

    Gazeau, Frédéric; Quiblier, Christophe; Jansen, Jeroen M.; Gattuso, Jean-Pierre; Middelburg, Jack J.; Heip, Carlo H. R.

    2007-04-01

    Ocean acidification resulting from human emissions of carbon dioxide has already lowered and will further lower surface ocean pH. The consequent decrease in calcium carbonate saturation potentially threatens calcareous marine organisms. Here, we demonstrate that the calcification rates of the edible mussel (Mytilus edulis) and Pacific oyster (Crassostrea gigas) decline linearly with increasing pCO2. Mussel and oyster calcification may decrease by 25 and 10%, respectively, by the end of the century, following the IPCC IS92a scenario (~740 ppmv in 2100). Moreover, mussels dissolve at pCO2 values exceeding a threshold value of ~1800 ppmv. As these two species are important ecosystem engineers in coastal ecosystems and represent a large part of worldwide aquaculture production, the predicted decrease of calcification in response to ocean acidification will probably have an impact on coastal biodiversity and ecosystem functioning as well as potentially lead to significant economic loss.

  3. Idiopathic Basal Ganglia Calcification Presented with Impulse Control Disorder

    PubMed Central

    Sahin, Cem; Levent, Mustafa; Akbaba, Gulhan; Kara, Bilge; Yeniceri, Emine Nese; Inanc, Betul Battaloglu

    2015-01-01

    Primary familial brain calcification (PFBC), also referred to as Idiopathic Basal Ganglia Calcification (IBGC) or “Fahr's disease,” is a clinical condition characterized by symmetric and bilateral calcification of globus pallidus and also basal ganglions, cerebellar nuclei, and other deep cortical structures. It could be accompanied by parathyroid disorder and other metabolic disturbances. The clinical features are dysfunction of the calcified anatomic localization. IBGC most commonly presents with mental damage, convulsion, parkinson-like clinical picture, and neuropsychiatric behavior disorders; however, presentation with impulse control disorder is not a frequent presentation. In the current report, a 43-year-old male patient who has been admitted to psychiatry policlinic with the complaints of aggressive behavior episodes and who has been diagnosed with impulse control disorder and IBGC was evaluated in the light of the literature. PMID:26246920

  4. A Premature Infant with Fetal Myocardial and Abdominal Calcifications and Factor V Leiden Homozygosity

    PubMed Central

    Parker, Margaret G.K.; Webster, Gregory; Insoft, Robert M.

    2014-01-01

    We present a premature male neonate with confirmed Factor V Leiden deficiency diagnosed prenatally with cardiac and abdominal calcifications. Our patient’s findings suggest that clinicians consider thromboembolic conditions when multiple fetal calcifications are visualized. PMID:19861970

  5. Alkalinity Enrichment Enhances Net Calcification of a Coral Reef Flat

    NASA Astrophysics Data System (ADS)

    Albright, R.; Caldeira, K.

    2015-12-01

    Ocean acidification is projected to shift reefs from a state of net accretion to one of net dissolution sometime this century. While retrospective studies show large-scale changes in coral calcification over the last several decades, it is not possible to unequivocally link these results to ocean acidification due to confounding factors of temperature and other environmental parameters. Here, we quantified the calcification response of a coral reef flat to alkalinity enrichment to test whether reef calcification increases when ocean chemistry is restored to near pre-industrial conditions. We used sodium hydroxide (NaOH) to increase the total alkalinity of seawater flowing over a reef flat, with the aim of increasing carbonate ion concentrations [CO32-] and the aragonite saturation state (Ωarag) to values that would have been attained under pre-industrial atmospheric pCO2 levels. We developed a dual tracer regression method to estimate alkalinity uptake (i.e., calcification) in response to alkalinity enrichment. This approach uses the change in ratios between a non-conservative tracer (alkalinity) and a conservative tracer (a non-reactive dye, Rhodamine WT) to assess the fraction of added alkalinity that is taken up by the reef as a result of an induced increase in calcification rate. Using this method, we estimate that an average of 17.3% ± 2.3% of the added alkalinity was taken up by the reef community. In providing results from the first seawater chemistry manipulation experiment performed on a natural coral reef community (without artificial confinement), we demonstrate that, upon increase of [CO32-] and Ωarag to near pre-industrial values, reef calcification increases. Thus, we conclude that, the impacts of ocean acidification are already being felt by coral reefs. This work is the culmination of years of work in the Caldeira lab at the Carnegie Institution for Science, involving many people including Jack Silverman, Kenny Schneider, and Jana Maclaren.

  6. Reversal of ocean acidification enhances net coral reef calcification.

    PubMed

    Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; Maclaren, Jana K; Mason, Benjamin M; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

    2016-03-17

    Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO3(2-)]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO3(2-)], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth. PMID:26909578

  7. Reversal of ocean acidification enhances net coral reef calcification.

    PubMed

    Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; Maclaren, Jana K; Mason, Benjamin M; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

    2016-03-17

    Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO3(2-)]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO3(2-)], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth.

  8. The association of bone and osteoclasts with vascular calcification.

    PubMed

    Han, Kum Hyun; Hennigar, Randolph A; O'Neill, W Charles

    2015-12-01

    The presence of bone tissue in calcified arteries may provide insights into the pathophysiology and potential reversibility of calcification, but the prevalence, distribution, and determinants of bone and osteoclasts in calcified arteries are unknown. Specimens of 386 arteries from lower limb amputations in 108 patients were examined retrospectively. Calcification was present in 282 arteries from 89 patients, which was medial in 64%, intimal in 9%, and both in 27%. Bone was present in 6% of arteries, essentially all of which were heavily calcified. Multiple sampling revealed that the true prevalence of bone in heavily calcified arteries was 25%. Bone was more common in medial rather than intimal calcifications (10% vs 3%, p=0.03) but did not vary with artery location (above vs below the knee). Heavily calcified arteries with bone were more likely to come from patients who were older (p=0.04), had diabetes (p=0.06), or were receiving warfarin (p=0.06), but there was no association with gender or renal failure. Bone was almost always adjacent to calcifications, along the periphery, but never within. Staining for the bone-specific proteins osteocalcin and osterix was noted in 20% and 45% of heavily calcified arteries without visible bone. Osteoclasts were present in 4.9% of arteries, all of which were heavily calcified and most of which contained bone. The frequent absence of bone in heavily calcified vessels and the histologic pattern strongly suggests a secondary rather than primary event. Recruitment of osteoclasts to vascular calcifications can occur but is rare, suggesting a limited capacity to reverse calcifications.

  9. Early detection of ocean acidification effects on marine calcification

    SciTech Connect

    Ilyina, T.; Zeebe, R. E.; E. Maier-Reimer; C. Heinze

    2009-02-19

    Ocean acidification is likely to impact calcification rates in many pelagic organisms, which may in turn cause significant changes in marine ecosystem structure. We examine effects of changes in marine CaCO3 production on total alkalinity (TA) in the ocean using the global biogeochemical ocean model HAMOCC. We test a variety of future calcification scenarios because experimental studies with different organisms have revealed a wide range of calcification sensitivities to CaCO3 saturation state. The model integrations start at a preindustrial steady state in the year 1800 and run until the year 2300 forced with anthropogenic CO2 emissions. Calculated trends in TA are evaluated taking into account the natural variability in ocean carbonate chemistry, as derived from repeat hydrographic transects. We conclude that the data currently available does not allow discerning significant trends in TA due to changes in pelagic calcification caused by ocean acidification. Given different calcification scenarios, our model calculations indicate that the TA increase over time will start being detectable by the year 2040, increasing by 5–30 umol/kg compared to the present-day values. In a scenario of extreme reductions in calcification, large TA changes relative to preindustrial conditions would have occurred at present, which we consider very unlikely. However, the time interval of reliable TA observations is too short to disregard this scenario. The largest increase in surface ocean TA is predicted for the tropical and subtropical regions. In order to monitor and quantify possible early signs of acidification effects, we suggest to specifically target those regions during future ocean chemistry surveys.

  10. Reversal of ocean acidification enhances net coral reef calcification

    NASA Astrophysics Data System (ADS)

    Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; MacLaren, Jana K.; Mason, Benjamin M.; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L.; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

    2016-03-01

    Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO32-]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO32-], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth.

  11. [Mechanism of losartan suppressing vascular calcification in rat aortic artery].

    PubMed

    Shao, Juan; Wu, Panfeng; Wu, Jiliang; Li, Mincai

    2016-08-01

    Objective To investigate the effect of the angiotensin II receptor 1 (AT1R) blocker losartan on vascular calcification in rat aortic artery and explore the underlying mechanisms. Methods SD rats were divided randomly into control group, vascular calcification model group and treatment group. Vascular calcification models were made by subcutaneous injection of warfarin plus vitamin K1 for two weeks. Rats in the treatment group were subcutaneously injected with losartan (10 mg/kg) at the end of the first week and consecutively for one week. We observed the morphological changes by HE staining and the calcium deposition by Alizarin red staining in the artery vascular wall. The mRNA expressions of bone morphogenetic protein 2 (BMP2) and Runt-related transcription factor 2 (RUNX2) were analyzed by reverse transcription PCR. The BMP2 and RUNX2 protein expressions were determined by Western blotting. The apoptosis of smooth muscle cells (SMCs) were detected by TUNEL. The AT1R expression was tested by fluorescent immunohistochemistry. Results The aortic vascular calcification was induced by warfarin and vitamin K1. Compared with the vascular calcification model group, the mRNA and protein expressions of BMP2 and RUNX2 were significantly downregulated in the aorta in the losartan treatment group. Furthermore, the apoptosis of SMCs and the AT1R expression obviously decreased. Conclusion AT1R blocker losartan inhibits the apoptosis of SMCs and reduces AT1R expression; it downregulates the BMP2 and RUNX2 expressions in the vascular calcification process. PMID:27412937

  12. The influence of surface reflectance anisotropy on estimation of soil properties

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Harm; Roosjen, Peter; Clevers, Jan

    2014-05-01

    The spatial variation in soil properties is an important factor for agricultural management. Unmanned airborne vehicles (UAV's) equipped with a hyperspectral mapping system may provide these data, but anisotropic reflectance effects may have an influence on the derived soil properties. Besides influencing the reflectance, angular observations may deliver added information about soil properties. We investigated the anisotropic behavior of 59 soil samples with a large variation in soil composition, by measuring their reflectance (350-2500 nm) over 92 different angles using a robot-based laboratory goniometer system. The results show that the anisotropic behavior of the soils influences the measured reflectance significantly, which limits the accurate prediction of soil properties (OM and clay especially). However, prediction accuracies of OM increase when spectra are measured under specific angles. Prediction accuracies further increase when a combination of observation angles is being used. Apart from that, using UAV's the wavelength range is limited to about 1000 nm. In general, this will decrease the model performance, but our results show that this effect can largely be compensated by combining multiple observation angles. Altogether, we demonstrate that surface anisotropy influences the prediction of soil properties negatively. This effect can be reduced by combining spectra acquired under different angles. Moreover, predictions can be improved if combinations of different observation angles are used.

  13. Absorption measurement of thin films by using photothermal techniques: The influence of thermal properties

    SciTech Connect

    Wu, Z.L.; Kuo, P.K.; Thomas, R.L.; Fan, Z.X.

    1995-12-31

    Photothermal techniques are widely used for measuring optical absorption of thin film coatings. In these applications the calibration of photothermal signal is typically based on the assumption that the thermal properties of the thin film make very little contribution. In this paper we take mirage technique as an example and present a detailed analysis of the influence of thin film thermal properties on absorption measurements. The results show that the traditional calibration method is not valid on surprisingly many situations.

  14. Symmetrical infantile thalamic degeneration with focal cytoplasmic calcification.

    PubMed

    Ambler, M; O'Neil, W

    1975-10-27

    Infantile thalamic degeneration is a rare clinico-pathological entity. Restricted location of the lesion and peculiar cytopathological changes serve to distinguish this disorder from other common encephalopathies. Optical and ultrastructural studies demonstrate cytoplasmic calcopherules in previously viable cells. According to current concepts of acute cellular reactions to injury and mechanism of intracellular calcification, the cytological changes cannot be attributed to either hypoxic ischemic cell change or dystrophic calcification. By analogy to other human and pathological material, the most likely basis for nondystrophic calcopherule formation is toxic or infectious injury with local synthesis, or autophagic or phagolysosomal degradation of cellular debris of specific chemical composition favoring calcium deposition.

  15. Evaluation and nonsurgical management of rotator cuff calcific tendinopathy.

    PubMed

    Greis, Ari C; Derrington, Stephen M; McAuliffe, Matthew

    2015-04-01

    Rotator cuff calcific tendinopathy is a common finding that accounts for about 7% of patients with shoulder pain. There are numerous theories on the pathogenesis of rotator cuff calcific tendinopathy. The diagnosis is confirmed with radiography, MRI or ultrasound. There are numerous conservative treatment options available and most patients can be managed successfully without surgical intervention. Nonsteroidal anti-inflammatory drugs and multiple modalities are often used to manage pain and inflammation; physical therapy can help improve scapular mechanics and decrease dynamic impingement; ultrasound-guided needle aspiration and lavage techniques can provide long-term improvement in pain and function in these patients.

  16. Prevention of vascular calcification with bisphosphonates without affecting bone mineralization: a new challenge?

    PubMed

    Neven, Ellen G; De Broe, Marc E; D'Haese, Patrick C

    2009-03-01

    Arterial calcification has been found to coexist with bone loss. Bisphosphonates, used as standard therapy for osteoporosis, inhibit experimentally induced vascular calcification, offering perspectives for the treatment of vascular calcification in renal failure patients. However, Lomashvili et al. report that the doses of etidronate and pamidronate that are effective in attenuating aortic calcification also decrease bone formation and mineralization in uremic rats, limiting their therapeutic use as anticalcifying agents.

  17. Influence of PSMC and other mineral admixtures on the properties of cement mortar

    NASA Astrophysics Data System (ADS)

    Xu, George Jianzhou

    PSMC is a waste material produced from pyrolysis of Sheet Molding Compound. The material consists of 35% fibreglass, 55% CaCOsb3 and 10% carbon. In this thesis, PSMC and seven other related materials have been investigated for their influences on the overall properties of cement mortar. The materials under investigation in addition to PSMC are the fibreglass part of PSMC (PG), the filler part of PSMC (C+Ca), the ground virgin fibreglass (RG), the virgin CaCOsb3 powder, the pyrolysed automotive fluff (PAF). For comparison, one class-F fly ash (FA), and one condensed silica fume (CSF) were also tested. The mortar properties that were studied include workability, strength, drying shrinkage, alkali-silica reactivity, sulphate resistance, freezing-thawing expansion, salt scaling resistance, and wet-dry expansion. The pore structures were also studied using water absorption and water evaporation techniques. It was found that PSMC increased the compressive strength, mitigated the ASR expansion and improved the sulphate resistance of cement mortar. All these improvements were largely due to the fibreglass content in the PSMC. Ground fibreglass was found to be a very effective material to improve the properties of cement mortar. It increased the compressive strength, reduced long term drying shrinkage, mitigated the ASR expansion, improved sulphate resistance, decreased the freeze-thaw weight loss and greatly enhanced the salt scaling resistance of cement mortar. The influence of fly ash and condensed silica fume on the properties of cement mortar was found to be similar to that of ground fibreglass. It was also found that the pore structure of cement mortars was greatly influenced by the mineral admixtures which possess pozzolanic properties. From a statistical analysis, it was concluded that the influence of mineral admixtures on the properties of cement mortar can be explained by their influence on three pore related factors. These factors are the porosity factor, the

  18. Temperature modulates coccolithophorid sensitivity of growth, photosynthesis and calcification to increasing seawater pCO₂.

    PubMed

    Sett, Scarlett; Bach, Lennart T; Schulz, Kai G; Koch-Klavsen, Signe; Lebrato, Mario; Riebesell, Ulf

    2014-01-01

    Increasing atmospheric CO₂ concentrations are expected to impact pelagic ecosystem functioning in the near future by driving ocean warming and acidification. While numerous studies have investigated impacts of rising temperature and seawater acidification on planktonic organisms separately, little is presently known on their combined effects. To test for possible synergistic effects we exposed two coccolithophore species, Emiliania huxleyi and Gephyrocapsa oceanica, to a CO₂ gradient ranging from ∼0.5-250 µmol kg⁻¹ (i.e. ∼20-6000 µatm pCO₂) at three different temperatures (i.e. 10, 15, 20°C for E. huxleyi and 15, 20, 25°C for G. oceanica). Both species showed CO₂-dependent optimum-curve responses for growth, photosynthesis and calcification rates at all temperatures. Increased temperature generally enhanced growth and production rates and modified sensitivities of metabolic processes to increasing CO₂. CO₂ optimum concentrations for growth, calcification, and organic carbon fixation rates were only marginally influenced from low to intermediate temperatures. However, there was a clear optimum shift towards higher CO₂ concentrations from intermediate to high temperatures in both species. Our results demonstrate that the CO₂ concentration where optimum growth, calcification and carbon fixation rates occur is modulated by temperature. Thus, the response of a coccolithophore strain to ocean acidification at a given temperature can be negative, neutral or positive depending on that strain's temperature optimum. This emphasizes that the cellular responses of coccolithophores to ocean acidification can only be judged accurately when interpreted in the proper eco-physiological context of a given strain or species. Addressing the synergistic effects of changing carbonate chemistry and temperature is an essential step when assessing the success of coccolithophores in the future ocean.

  19. Placental calcifications: a clue for the identification of high-risk fetuses in the low-risk pregnant population?

    PubMed

    Mastrolia, Salvatore Andrea; Weintraub, Adi Yehuda; Sciaky-Tamir, Yael; Tirosh, Dan; Loverro, Giuseppe; Hershkovitz, Reli

    2016-03-01

    "What does it mean, Doctor?" and "Is it going to affect my baby in some way?". Those are the most typical questions of pregnant women to obstetricians. Answering is sometimes easier but placental calcification is not the case, since placental architecture and disease are two different faces of the same coin and the association between them is not completely clear. Placenta can function properly, even in the presence of architectural alterations, without any fetal consequences. So, remains the question, when does a placental structural anomaly become a sign of increased attention to maternal conditions, fetal development and well-being? The present review will analyze these concepts, with emphasis on placental calcification, its pathogenesis, and the state-of-the-art regarding the influence of this finding on pregnancy outcomes among low-risk pregnant patients.

  20. Influence of jet-cooking Prowashonupana barley flour on phenolic composition, antioxidant activities, and viscoelastic properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of jet-cooking Prowashonupana barley flour on total phenolic contents, antioxidant activities, water holding capacities, and viscoelastic properties was studied. Barley flour was jet-cooked without or with pH adjustment at 7, 9, or 11. Generally, the free phenolic content and antioxi...

  1. Influence of the refractive index and dispersion of spectacle lens on its imaging properties

    NASA Astrophysics Data System (ADS)

    Miks, Antonin; Novak, Jiri; Novak, Pavel

    2007-12-01

    The paper shows an influence of the refractive index and dispersion of the spectacle lens on its imaging properties. Relations are presented for calculation of radii of curvature of anastigmatic spectacle lenses and their chromatic aberration. Moreover, the formulas are derived for calculation of the change of astigmatism of spectacle lens due to dispersion of spectacle lens material.

  2. Influence of Specific Features of Twin Arc Welding on Properties of Weld Joints

    NASA Astrophysics Data System (ADS)

    Sholokhov, M. A.; Melnikov, A. U.; Fiveyskiy, A. M.

    2016-04-01

    The present article covers the influence of standard and narrow gap twin arc welding on properties of weld joints from high-strength steels. While analyzing microsections we established that distribution of micro structure and phase terms, as well the distribution of micro-hardness, were more homogeneous under narrow gap twin arc welding.

  3. Environmental and centrifugal factors influencing the visco-elastic properties of oral biofilms in vitro.

    PubMed

    Peterson, Brandon W; Busscher, Henk J; Sharma, Prashant K; van der Mei, Henny C

    2012-01-01

    Centrifugal compaction causes changes in the surface properties of bacterial cells. It has been shown previously that the surface properties of planktonic cells change with increasing centrifugal compaction. This study aimed to analyze the influences of centrifugal compaction and environmental conditions on the visco-elastic properties of oral biofilms. Biofilms were grown out of a layer of initially adhering streptococci, actinomyces or a combination of these. Different uni-axial deformations were induced on the biofilms and the load relaxations were measured over time. Linear-Regression-Analysis demonstrated that both the centrifugation coefficient for streptococci and induced deformation influenced the percentage relaxation. Centrifugal compaction significantly influenced relaxation only upon compression of the outermost 20% of the biofilm (p < 0.05), whereas biofilm composition became influential when 50% deformation was induced, invoking re-arrangement of the bacteria in deeper biofilm structures. In summary, the effects of centrifugal compaction of initially adhering, centrifuged bacteria extend to the visco-elastic properties of biofilms, indicating that the initial bacterial layer influences the structure of the entire biofilm.

  4. Influence of color on dielectric properties of marinated poultry breast meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dielectric behavior of foods when exposed to radio-frequency and microwave electric fields is highly influenced by moisture content and the degree of water binding with constituents of the food materials. The ability to correlate specific food quality characteristics with the dielectric properti...

  5. Molecular characterization of biochars and their influence on microbiological properties of soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The composition and surface chemistry of carbon rich biochar materials is highly uncertain and believed to change with feedstock and biomass conversion process. The tentative connection between the biochar surface chemical properties and their influence on microbially mediated mineralization of C, N...

  6. The kinetics of Dissolution of Biologically Formed Calcific Deposits.

    NASA Astrophysics Data System (ADS)

    Rokidi, Stamatia; Koutsoukos, Petros

    2015-04-01

    The calcification of aortic valves results in the formation of non stoichiometric apatitic deposits which may have serious health implications because of the fact that these minerals adhere tenaciously on tissues like heart valves and arteries causing permanent damage which is partly due to their low solubility. In the present work, calcium phosphate biominerals were extracted from clinically removed tissues and were characterized with respect to their mineralogical constituents and other properties including morphology, specific surface area analyses and thermogravimetric analysis. In all cases, the biominerals may be described as non stoichiometric apatitic materials, although traces of the precursor phase of octacalcium phosphate (Ca8H2(PO4)6•5H2O, OCP) were identified on the basis of their morphological examination. The kinetics of dissolution of the biomineral deposits was investigated in solutions undersaturated with respect to hydroxyapatite (Ca5(PO4)3OH, HAP) at conditions of constant undersaturation at pH 7.40, 37°C, 0.15M NaCl. Synthetic stoichiometric HAP was used as the control mineral. The experiments in the present work used solutions prepared from calcium chloride and sodium hydrogen phosphate and the relative undersaturation, σ, was in the range 0.38-0.74 with respect to HAP and 0.49-0.85 with respect to OCP (σ=1 in water). The dissolution process started immediately upon the introduction of an accurately weighted amount of powdered biomineral in the undersaturated solutions homogenized by magnetic stirring. Inert atmosphere was ensured with the bubbling of water vapor saturated nitrogen through the demineralizing solutions. A glass/Ag/AgCl combination electrode was used as a probe to monitor the process and to control the addition of diluent solutions with the stoichiometry of the dissolving mineral. The measurements of the rates of crystal dissolution, showed a parabolic dependence on the relative solution undersaturation for HAP and higher

  7. The influence of surface functionalisation on the electrical properties and thermal stability of nanodiamonds

    NASA Astrophysics Data System (ADS)

    Welch, Joseph O.; Li, Pei; Chaudhary, Aysha; Edgington, Robert; Jackman, Richard B.

    2014-10-01

    Detonation nanodiamond (ND) has recently emerged as a useful new class of diamond material. However, to date there has been little investigation of the electrical properties of this material. Due to the nanoscale dimensions, the surface functionalisation of the individual ND is of particular importance to the characteristics of ND films. Here, hydrogen and oxygen termination of ND, verified using Fourier transform infrared spectroscopy, are shown to strongly influence the electronic properties of NDs. Hydrogen terminated ND exhibiting a far greater resilience to thermal decomposition when compared to the oxygen terminated NDs. Moreover, H-NDs also displayed so-called "surface conductivity," a property displayed by hydrogen-terminated bulk diamond films, whilst O-NDs display properties high resistivity. These results indicate that under the correct conditions ND layers can display similar electrical properties to "bulk" diamond thin films.

  8. The influence of surface functionalisation on the electrical properties and thermal stability of nanodiamonds

    SciTech Connect

    Welch, Joseph O; Li, Pei; Chaudhary, Aysha; Edgington, Robert; Jackman, Richard B.

    2014-10-07

    Detonation nanodiamond (ND) has recently emerged as a useful new class of diamond material. However, to date there has been little investigation of the electrical properties of this material. Due to the nanoscale dimensions, the surface functionalisation of the individual ND is of particular importance to the characteristics of ND films. Here, hydrogen and oxygen termination of ND, verified using Fourier transform infrared spectroscopy, are shown to strongly influence the electronic properties of NDs. Hydrogen terminated ND exhibiting a far greater resilience to thermal decomposition when compared to the oxygen terminated NDs. Moreover, H-NDs also displayed so-called “surface conductivity,” a property displayed by hydrogen-terminated bulk diamond films, whilst O-NDs display properties high resistivity. These results indicate that under the correct conditions ND layers can display similar electrical properties to “bulk” diamond thin films.

  9. Antibacterial Properties of Copper Nanoparticle Dispersions: Influence of Synthesis Conditions and Physicochemical Characteristics

    NASA Astrophysics Data System (ADS)

    Godymchuk, A.; Frolov, G.; Gusev, A.; Zakharova, O.; Yunda, E.; Kuznetsov, D.; Kolesnikov, E.

    2015-11-01

    The production of bactericidal plasters, bandages and medicines with the inclusion of copper nanoparticles and copper ions may have a great potential in terms of their biomedical application. The work considers the influence of the synthesis conditions, size, aggregation status, and charge of nanoparticles in aqueous solutions as well as the type of microorganisms to the antibacterial properties of water suspensions of electroexplosive copper nanoparticles in the conditions in vitro in relation to strains Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus. Water dispersions of copper nanoparticles were shown to inhibit the growth of test cells for both G+ and G- microbacteria but the degree of such an influence strongly depended on the type of a test strain. The authors have demonstrated that use of deeply purified water and alcohol-containing stabilizers at the synthesis of nanoparticles via metals electric erosion in the liquid prevents the copper nanoparticles coagulation and significantly influences on their physicochemical characteristics and, consequently, antibacterial properties.

  10. Influence of process variables on the properties of laccase biobleached pulps.

    PubMed

    Martin-Sampedro, Raquel; Miranda, Jesús; García-Fuentevilla, Luisa L; Hernández, Manuel; Arias, Maria E; Diaz, Manuel J; Eugenio, Maria E

    2015-01-01

    A laccase stage can be used as a pre-treatment of a standard chemical bleaching sequence to reduce environmental concerns associated to this process. The importance of each independent variable and its influence on the properties of the bleached pulp have been studied in depth in this work, using an adaptive network-based fuzzy inference system (ANFIS) with four independent variables (laccase, buffer, mediator and oxygen) as input. Eucalyptus globulus kraft pulp was biobleached using a laccase from Pycnoporus sanguineus and a natural mediator (acetosyringone). Later, an alkaline extraction and a hydrogen peroxide treatment were applied. Most biobleaching processes showed a decrease in kappa number and an increase in brightness with no significant impact on the viscosity values, compared with the control. Oxygen was the variable with the smallest influence on the final pulp properties while the laccase and buffer solution showed a significant influence. PMID:25085529

  11. Intracranial physiological calcifications in adults on computed tomography in Tabriz, Iran.

    PubMed

    Daghighi, M H; Rezaei, V; Zarrintan, S; Pourfathi, H

    2007-05-01

    Intracranial physiological calcifications are unaccompanied by any evidence of disease and have no demonstrable pathological cause. They are often due to calcium and sometimes iron deposition in the blood vessels of different structures of the brain. Computed tomography (CT) is the most sensitive means of detection of these calcifications. The aim of this study was the assessment of intracranial physiological calcifications in adults. We studied 1569 cases ranging in age from 15 to 85 in Tabriz Imam Khomeini Hospital, Iran. These patients had a history of head trauma and their CT scan did not show any evidence of pathological findings. The structures evaluated consisted of (A) the pineal gland, (B) the choroid plexus, (C) the habenula, (D) the basal ganglia, (E) the tentorium cerebelli, sagittal sinus and falx cerebri, (F) vessels and (G) lens and other structures which could be calcified. Of the 1569 subjects, 71.0% had pineal calcification, 66.2% had choroid plexus calcification, 20.1% had habenular calcification, 7.3% had tentorium cerebelli, sagittal sinus or falx cerebri calcifications, 6.6% had vascular calcification, 0.8% had basal ganglia calcification and 0.9% had lens and other non-defined calcifications. In general, the frequency of intracranial physiological calcifications was greater in men than in women. All types of calcification increased at older ages except for lens and other non-defined calcifications. We evaluated all the cranial structures and determined percentages for all types of intracranial physiological calcification. These statistics can be used for comparing physiological and pathological intracranial calcifications. Moreover, these statistics may be of interest from the clinical perspective and are potentially of clinical use. PMID:17594669

  12. Influence Of The Laser Cladding Strategies On The Mechanical Properties Of Inconel 718

    SciTech Connect

    Lamikiz, A.; Tabernero, I.; Ukar, E.; Lopez de Lacalle, L. N.

    2011-01-17

    This work presents different experimental results of the mechanical properties of Inconel registered 718 test parts built-up by laser cladding. Recently, turbine manufacturers for aeronautical sector have presented high interest on laser cladding processes. This process allows building fully functional structures on superalloys, such as Inconel registered 718, with high flexibility on complex shapes. However, there is limited data on mechanical properties of the laser cladding structures. Moreover, the available data do not include the influence of process parameters and laser cladding strategies. Therefore, a complete study of the influence of the laser cladding parameters and mainly, the variation of the tensile strength with the laser cladding strategy is presented. The results show that there is a high directionality of mechanical properties, depending on the strategies of laser cladding process. In other words, the test parts show a fiber -like structure that should be considered on the laser cladding strategy selection.

  13. Intracerebral metaplastic meningioma with prominent ossification and extensive calcification

    PubMed Central

    Huang, Jingxiang; Petersson, Fredrik

    2011-01-01

    We present a patient (male 26 years) with a short history of recurrent seizures induced by a largely intracerebrally located frontal lobe meningioma. The tumor displayed a heretofore unpublished combination of extensive metaplastic bone formation and prominent non-psammomatous calcifications with focal chicken-wire pattern. PMID:21769319

  14. Calcific Aortic Valve Stenosis: Methods, Models, and Mechanisms

    PubMed Central

    Miller, Jordan D.; Weiss, Robert M.; Heistad, Donald D.

    2011-01-01

    Calcific aortic valve stenosis (CAVS) is a major health problem facing aging societies. The identification of osteoblast-like and osteoclast-like cells in human tissue has led to a major paradigm shift in the field. CAVS was thought to be a passive, degenerative process, whereas now the progression of calcification in CAVS is considered to be actively regulated. Mechanistic studies examining the contributions of true ectopic osteogenesis, non-osseous calcification, and ectopic osteoblast-like cells (that appear to function differently from skeletal osteoblasts) to valvular dysfunction have been facilitated by the development of mouse models of CAVS. Recent studies also suggest that valvular fibrosis, as well as calcification, may play an important role in restricting cusp movement, and CAVS may be more appropriately viewed as a fibrocalcific disease. High resolution echocardiography and magnetic resonance imaging have emerged as useful tools for testing the efficacy of pharmacological and genetic interventions in vivo. Key studies in humans and animals are reviewed that have shaped current paradigms in the field of CAVS, and suggest promising future areas for research. PMID:21617136

  15. Inflammatory, metabolic, and genetic mechanisms of vascular calcification

    PubMed Central

    Demer, Linda L.; Tintut, Yin

    2014-01-01

    This review centers on updating the active research area of vascular calcification. This pathology underlies substantial cardiovascular morbidity and mortality, through adverse mechanical effects on vascular compliance, vasomotion, and, most likely, plaque stability. Biomineralization is a complex, regulated process occurring widely throughout nature. Decades ago, its presence in the vasculature was considered a mere curiosity and an unregulated, “dystrophic” process that does not involve biological mechanisms. While it remains controversial whether the process has any adaptive value or past evolutionary advantage, substantial advances have been made in understanding the biological mechanisms driving the process. Different types of calcific vasculopathy, such as inflammatory vs. metabolic, have parallel mechanisms in skeletal bone calcification, such as intramembranous and endochondral ossification. Recent work has identified important regulatory roles for inflammation, oxidized lipids, elastin, alkaline phosphatase, osteoprogenitor cells, matrix gamma-carboxyglutamic acid protein (MGP), transglutaminase, osteoclastic regulatory factors, phosphate regulatory hormones and receptors, apoptosis, prelamin A, autophagy, and microvesicles or microparticles similar to the matrix vesicles of skeletal bone. Recent work has uncovered fascinating interactions between MGP, vitamin K, warfarin and transport proteins. And, lastly, recent breakthroughs in inherited forms of calcific vasculopathy, have identified the genes responsible as well as an unexpected overlap of phenotypes. PMID:24665125

  16. [Vascular calcifications, the hidden side effects of vitamin K antagonists].

    PubMed

    Bennis, Youssef; Vengadessane, Subashini; Bodeau, Sandra; Gras, Valérie; Bricca, Giampiero; Kamel, Saïd; Liabeuf, Sophie

    2016-09-01

    Despite the availability of new oral anticoagulants, vitamin K antagonists (VKA, such as fluindione, acenocoumarol or warfarin) remain currently the goal standard medicines for oral prevention or treatment of thromboembolic disorders. They inhibit the cycle of the vitamin K and its participation in the enzymatic gamma-carboxylation of many proteins. The VKA prevent the activation of the vitamin K-dependent blood clotting factors limiting thus the initiation of the coagulation cascade. But other proteins are vitamin K-dependent and also remain inactive in the presence of VKA. This is the case of matrix Gla-protein (MGP), a protein that plays a major inhibitory role in the development of vascular calcifications. Several experimental and epidemiological results suggest that the use of the VKA could promote the development of vascular calcifications increasing thus the cardiovascular risk. This risk seems to be higher in patients with chronic kidney disease or mellitus diabetes who are more likely to develop vascular calcifications, and may be due to a decrease of the MGP activity. This review aims at summarizing the data currently available making vascular calcifications the probably underestimated side effects of VKA.

  17. Endothelial microparticles mediate inflammation-induced vascular calcification.

    PubMed

    Buendía, Paula; Montes de Oca, Addy; Madueño, Juan Antonio; Merino, Ana; Martín-Malo, Alejandro; Aljama, Pedro; Ramírez, Rafael; Rodríguez, Mariano; Carracedo, Julia

    2015-01-01

    Stimulation of endothelial cells (ECs) with TNF-α causes an increase in the expression of bone morphogenetic protein-2 (BMP-2) and the production of endothelial microparticles (EMPs). BMP-2 is known to produce osteogenic differentiation of vascular smooth muscle cells (VSMCs). It was found that EMPs from TNF-α-stimulated endothelial cells (HUVECs) contained a significant amount of BMP-2 and were able to enhance VSMC osteogenesis and calcification. Calcium content was greater in VSMCs exposed to EMPs from TNF-α-treated HUVECs than EMPs from nontreated HUVECs (3.56 ± 0.57 vs. 1.48 ± 0.56 µg/mg protein; P < 0.05). The increase in calcification was accompanied by up-regulation of Cbfa1 (osteogenic transcription factor) and down-regulation of SM22α (VSMC lineage marker). Inhibition of BMP-2 by small interfering RNA reduced the VSMC calcification induced by EMPs from TNF-α-treated HUVECs. Similar osteogenic capability was observed in EMPs from both patients with chronic kidney disease and senescent cells, which also presented a high level of BMP-2 expression. Labeling of EMPs with CellTracker shows that EMPs are phagocytized by VSMCs under all conditions (with or without high phosphate, control, and EMPs from TNF-α-treated HUVECs). Our data suggest that EC damage results in the release of EMPs with a high content of calcium and BMP-2 that are able to induce calcification and osteogenic differentiation of VSMCs.

  18. Severe prostatic calcification after radiation therapy for cancer.

    PubMed

    Jones, W A; Miller, E V; Sullivan, L D; Chapman, W H

    1979-06-01

    Severe symptomatic prostatic calcification was seen in 3 patients who had carcinoma of the prostate treated initially with transurethral resection, followed in 2 to 4 weeks by definitive radiation therapy. This complication is probably preventable if an interval of 6 weeks is allowed between transurethral resection of the prostate and radiation therapy.

  19. Low calcification in corals in the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-10-01

    Reef-building coral communities in the Great Barrier Reef—the world's largest coral reef—may now be calcifying at only about half the rate that they did during the 1970s, even though live coral cover may not have changed over the past 40 years, a new study finds. In recent decades, coral reefs around the world, home to large numbers of fish and other marine species, have been threatened by such human activities as pollution, overfishing, global warming, and ocean acidification; the latter affects ambient water chemistry and availability of calcium ions, which are critical for coral communities to calcify, build, and maintain reefs. Comparing data from reef surveys during the 1970s, 1980s, and 1990s with present-day (2009) measurements of calcification rates in One Tree Island, a coral reef covering 13 square kilometers in the southern part of the Great Barrier Reef, Silverman et al. show that the total calcification rates (the rate of calcification minus the rate of dissolution) in these coral communities have decreased by 44% over the past 40 years; the decrease appears to stem from a threefold reduction in calcification rates during nighttime.

  20. Endothelial microparticles mediate inflammation-induced vascular calcification.

    PubMed

    Buendía, Paula; Montes de Oca, Addy; Madueño, Juan Antonio; Merino, Ana; Martín-Malo, Alejandro; Aljama, Pedro; Ramírez, Rafael; Rodríguez, Mariano; Carracedo, Julia

    2015-01-01

    Stimulation of endothelial cells (ECs) with TNF-α causes an increase in the expression of bone morphogenetic protein-2 (BMP-2) and the production of endothelial microparticles (EMPs). BMP-2 is known to produce osteogenic differentiation of vascular smooth muscle cells (VSMCs). It was found that EMPs from TNF-α-stimulated endothelial cells (HUVECs) contained a significant amount of BMP-2 and were able to enhance VSMC osteogenesis and calcification. Calcium content was greater in VSMCs exposed to EMPs from TNF-α-treated HUVECs than EMPs from nontreated HUVECs (3.56 ± 0.57 vs. 1.48 ± 0.56 µg/mg protein; P < 0.05). The increase in calcification was accompanied by up-regulation of Cbfa1 (osteogenic transcription factor) and down-regulation of SM22α (VSMC lineage marker). Inhibition of BMP-2 by small interfering RNA reduced the VSMC calcification induced by EMPs from TNF-α-treated HUVECs. Similar osteogenic capability was observed in EMPs from both patients with chronic kidney disease and senescent cells, which also presented a high level of BMP-2 expression. Labeling of EMPs with CellTracker shows that EMPs are phagocytized by VSMCs under all conditions (with or without high phosphate, control, and EMPs from TNF-α-treated HUVECs). Our data suggest that EC damage results in the release of EMPs with a high content of calcium and BMP-2 that are able to induce calcification and osteogenic differentiation of VSMCs. PMID:25342130

  1. Metastatic calcification of the stomach imaged on a bone scan

    SciTech Connect

    Goldstein, R.; Ryo, U.Y.; Pinsky, S.M.

    1984-10-01

    A whole body bone scan obtained on a 21-year-old woman with sickle cell disease and chronic renal failure showed localization of the radionuclide diffusely in the stomach. The localization of the radionuclide represented metastatic calcification of the stomach caused by secondary hyperparathyroidism.

  2. Familial idiopathic basal ganglia calcification (Fahr’s disease)

    PubMed Central

    Mufaddel, Amir A.; Al-Hassani, Ghanem A.

    2014-01-01

    Familial idiopathic basal ganglia calcification (Fahr’s disease) is a rare neurodegenerative disorder characterized by symmetrical and bilateral calcification of the basal ganglia. Calcifications may also occur in other brain regions such as dentate nucleus, thalamus, and cerebral cortex. Both familial and non-familial cases of Fahr’s disease have been reported, predominantly with autosomal-dominant fashion. The disease has a wide range of clinical presentations, predominantly with neuropsychiatric features and movement disorders. Psychiatric features reported in the literature include: cognitive impairment, depression, hallucinations, delusions, manic symptoms, anxiety, schizophrenia-like psychosis, and personality change. Other clinical features include: Parkinsonism, ataxia, headache, seizures, vertigo, stroke-like events, orthostatic hypotension, tremor, dysarthria, and paresis. Fahr’s disease should be considered in the differential diagnosis of psychiatric symptoms, particularly when associated with movement disorder. The disease should be differentiated from other conditions that can cause intracranial calcification. No specific treatment is currently available. Further research is needed to bridge the gap existing in our current knowledge of the prevalence, etiology, symptoms, and treatment of Fahr’s disease. PMID:24983277

  3. Familial idiopathic basal ganglia calcification (Fahr`s disease).

    PubMed

    Mufaddel, Amir A; Al-Hassani, Ghanem A

    2014-07-01

    Familial idiopathic basal ganglia calcification (Fahr`s disease) is a rare neurodegenerative disorder characterized by symmetrical and bilateral calcification of the basal ganglia. Calcifications may also occur in other brain regions such as dentate nucleus, thalamus, and cerebral cortex. Both familial and non-familial cases of Fahr`s disease have been reported, predominantly with autosomal-dominant fashion. The disease has a wide range of clinical presentations, predominantly with neuropsychiatric features and movement disorders. Psychiatric features reported in the literature include: cognitive impairment, depression, hallucinations, delusions, manic symptoms, anxiety, schizophrenia-like psychosis, and personality change. Other clinical features include: Parkinsonism, ataxia, headache, seizures, vertigo, stroke-like events, orthostatic hypotension, tremor, dysarthria, and paresis. Fahr`s disease should be considered in the differential diagnosis of psychiatric symptoms, particularly when associated with movement disorder. The disease should be differentiated from other conditions that can cause intracranial calcification. No specific treatment is currently available. Further research is needed to bridge the gap existing in our current knowledge of the prevalence, etiology, symptoms, and treatment of Fahr`s disease.

  4. A red herring in vascular calcification: ‘nanobacteria’ are protein–mineral complexes involved in biomineralization

    PubMed Central

    Krüger, Thilo; Heiss, Alexander; Jahnen-Dechent, Willi

    2011-01-01

    Biomineralization at pathological extraosseous sites (i.e. vasculature and soft tissues) is associated with increased morbidity and mortality. So-called ‘nanobacteria’ have been described as pathogenic agents causing many diseases including calcification. Initially, their appearance, and having a content consisting of nucleic acids plus proteins and properties of growing structures, suggested that they were living organisms. However, it could be demonstrated that the so-called nanobacteria were in fact mineralizing nanoparticles that contain mineral and non-mineral compounds, that these particles bind to charged molecules and that supersaturation enables in vitro growth of these nanoparticles. Recent data indicate that nanoparticles consisting of protein–mineral complexes can be seen both in vitro and in vivo as precursors of matrix calcification. PMID:21965584

  5. Isolation and Culture of Aortic Smooth Muscle Cells and In Vitro Calcification Assay.

    PubMed

    Villa-Bellosta, Ricardo; Hamczyk, Magda R

    2015-01-01

    Elevated serum phosphorus is a major risk factor for vascular calcification, which is characterized by the presence of calcium phosphate deposits, mainly hydroxyapatite crystals. In vitro studies of phosphate-induced calcification show that vascular smooth muscle cells undergo calcification with features similar to those observed in pathological vascular calcification in vivo, including the presence of hydroxyapatite crystals. Here, we describe the double-collagenase digestion method for isolating vascular smooth muscle cells from aorta, and a method for inducing calcification in vitro using high phosphate concentration.

  6. Evaluation of regional cerebral blood flow in patient with atypical senile dementia with asymmetrical calcification.

    PubMed

    Shoyama, Masaru; Ukai, Satoshi; Shinosaki, Kazuhiro

    2015-12-01

    We report an 83-year-old woman with atypical senile dementia with Fahr-type calcification. Brain computed tomography demonstrated asymmetrical calcification predominant in the basal ganglia on the right side and pronounced diffuse cortical atrophy in the frontotemporal areas. The patient was clinically diagnosed with diffuse neurofibrillary tangles with calcification. Brain single photon emission computed tomography findings revealed that cerebral blood flow was reduced on the right side, as compared with the left side, in widespread areas. Hemispheric asymmetry in both calcification and cerebral blood flow suggests a relationship between calcification and vascular changes. PMID:25737312

  7. Physical oceanographic processes influence bio-optical properties in the Tasman Sea

    NASA Astrophysics Data System (ADS)

    Cherukuru, Nagur; Davies, Peter L.; Brando, Vittorio E.; Anstee, Janet M.; Baird, Mark E.; Clementson, Lesley A.; Doblin, Martina A.

    2016-04-01

    Remote sensing observations show optical signatures to conform to the physical oceanographic patterns in the Tasman Sea. To test the link between physical oceanographic processes and bio-optical properties we investigated an in situ bio-optical dataset collected in the Tasman Sea. Analysis of in situ observations showed the presence of four different water masses in the Tasman Sea, formed by the relatively warm and saline East Australia Current (EAC) water, a mesoscale cold core eddy on the continental slope, cooler Tasman Sea water on the shelf and river plume water. The distribution of suspended substances and their inherent optical properties in these water masses were distinctly different. Light absorption and attenuation budgets indicate varying optical complexity between the water masses. Specific inherent optical properties of suspended particulate and dissolved substances in each group were different as they were influenced by physical and biogeochemical processes specific to that water mass. Remote sensing reflectance signature varied in response to changing bio-optical properties between the water masses; thus providing the link between physical oceanographic processes, bio-optical properties and the optical signature. Findings presented here extend our knowledge of the Tasman Sea, its optical environment and the role of physical oceanographic processes in influencing the inherent optical properties and remote sensing signature in this complex oceanographic region.

  8. Calcification by juvenile corals under heterotrophy and elevated CO2

    NASA Astrophysics Data System (ADS)

    Drenkard, E. J.; Cohen, A. L.; McCorkle, D. C.; de Putron, S. J.; Starczak, V. R.; Zicht, A. E.

    2013-09-01

    Ocean acidification (OA) threatens the existence of coral reefs by slowing the rate of calcium carbonate (CaCO3) production of framework-building corals thus reducing the amount of CaCO3 the reef can produce to counteract natural dissolution. Some evidence exists to suggest that elevated levels of dissolved inorganic nutrients can reduce the impact of OA on coral calcification. Here, we investigated the potential for enhanced energetic status of juvenile corals, achieved via heterotrophic feeding, to modulate the negative impact of OA on calcification. Larvae of the common Atlantic golf ball coral, Favia fragum, were collected and reared for 3 weeks under ambient (421 μatm) or significantly elevated (1,311 μatm) CO2 conditions. The metamorphosed, zooxanthellate spat were either fed brine shrimp (i.e., received nutrition from photosynthesis plus heterotrophy) or not fed (i.e., primarily autotrophic). Regardless of CO2 condition, the skeletons of fed corals exhibited accelerated development of septal cycles and were larger than those of unfed corals. At each CO2 level, fed corals accreted more CaCO3 than unfed corals, and fed corals reared under 1,311 μatm CO2 accreted as much CaCO3 as unfed corals reared under ambient CO2. However, feeding did not alter the sensitivity of calcification to increased CO2; ∆ calcification/∆Ω was comparable for fed and unfed corals. Our results suggest that calcification rates of nutritionally replete juvenile corals will decline as OA intensifies over the course of this century. Critically, however, such corals could maintain higher rates of skeletal growth and CaCO3 production under OA than those in nutritionally limited environments.

  9. The role of vitamin K in soft-tissue calcification.

    PubMed

    Theuwissen, Elke; Smit, Egbert; Vermeer, Cees

    2012-03-01

    Seventeen vitamin K-dependent proteins have been identified to date of which several are involved in regulating soft-tissue calcification. Osteocalcin, matrix Gla protein (MGP), and possibly Gla-rich protein are all inhibitors of soft-tissue calcification and need vitamin K-dependent carboxylation for activity. A common characteristic is their low molecular weight, and it has been postulated that their small size is essential for calcification inhibition within tissues. MGP is synthesized by vascular smooth muscle cells and is the most important inhibitor of arterial mineralization currently known. Remarkably, the extrahepatic Gla proteins mentioned are only partly carboxylated in the healthy adult population, suggesting vitamin K insufficiency. Because carboxylation of the most essential Gla proteins is localized in the liver and that of the less essential Gla proteins in the extrahepatic tissues, a transport system has evolved ensuring preferential distribution of dietary vitamin K to the liver when vitamin K is limiting. This is why the first signs of vitamin K insufficiency are seen as undercarboxylation of the extrahepatic Gla proteins. New conformation-specific assays for circulating uncarboxylated MGP were developed; an assay for desphospho-uncarboxylated matrix Gla protein and another assay for total uncarboxylated matrix Gla protein. Circulating desphospho-uncarboxylated matrix Gla protein was found to be predictive of cardiovascular risk and mortality, whereas circulating total uncarboxylated matrix Gla protein was associated with the extent of prevalent arterial calcification. Vitamin K intervention studies have shown that MGP carboxylation can be increased dose dependently, but thus far only 1 study with clinical endpoints has been completed. This study showed maintenance of vascular elasticity during a 3-y supplementation period, with a parallel 12% loss of elasticity in the placebo group. More studies, both in healthy subjects and in patients at risk

  10. Mammographic calcification cluster detection and threshold gold thickness measurements

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Mackenzie, A.; Cooke, J.; Given-Wilson, R.; Wallis, M. G.; Chakraborty, D. P.; Dance, D. R.; Young, K. C.

    2012-03-01

    European Guidelines for quality control in digital mammography specify acceptable and achievable standards of image quality (IQ) in terms of threshold gold thickness using the CDMAM test object. However, there is little evidence relating such measurements to cancer detection. This work investigated the relationship between calcification detection and threshold gold thickness. An observer study was performed using a set of 162 amorphous selenium direct digital (DR) detector images (81 no cancer and 81 with 1-3 inserted calcification clusters). From these images four additional IQs were simulated: different digital detectors (computed radiography (CR) and DR) and dose levels. Seven observers marked and rated the locations of suspicious regions. DBM analysis of variances was performed on the JAFROC figure of merit (FoM) yielding 95% confidence intervals for IQ pairs. Automated threshold gold thickness (Tg) analysis was performed for the 0.25mm gold disc diameter on CDMAM images at the same IQs (16 images per IQ). Tg was plotted against FoM and a power law fitted to the data. There was a significant reduction in FoM for calcification detection for CR images compared with DR; FoM decreased from 0.83 to 0.63 (p<=0.0001). Detection was also sensitive to dose. There was a good correlation between FoM and Tg (R2=0.80, p<0.05), consequently threshold gold thickness was a good predictor of calcification detection at the same IQ. Since the majority of threshold gold thicknesses for the various IQs were above the acceptable standard despite large variations in calcification detection by radiologists, current EU guidelines may need revising.

  11. Kangaroo vs. porcine aortic valves: calcification potential after glutaraldehyde fixation.

    PubMed

    Narine, K; Chéry, Cyrille C; Goetghebeur, Els; Forsyth, R; Claeys, E; Cornelissen, Maria; Moens, L; Van Nooten, G

    2005-01-01

    The aim of this study was to evaluate and compare the calcification potential of kangaroo and porcine aortic valves after glutaraldehyde fixation at both low (0.6%) and high (2.0%) concentrations of glutaraldehyde in the rat subcutaneous model. To our knowledge this is the first report comparing the time-related, progressive calcification of these two species in the rat subcutaneous model. Twenty-two Sprague-Dawley rats were each implanted with two aortic valve leaflets (porcine and kangaroo) after fixation in 0.6% glutaraldehyde and two aortic valve leaflets (porcine and kangaroo) after fixation in 2% glutaraldehyde respectively. Animals were sacrificed after 24 h and thereafter weekly for up to 10 weeks after implantation. Calcium content was determined using inductively coupled plasma-mass spectrometry and confirmed histologically. Mean calcium content per milligram of tissue (dry weight) treated with 0.6 and 2% glutaraldehyde was 116.2 and 110.4 microg/mg tissue for kangaroo and 95.0 and 106.8 microg/mg tissue for porcine valves. Calcium content increased significantly over time (8.8 microg/mg tissue per week) and was not significantly different between groups. Regression analysis of calcification over time showed no significant difference in calcification of valves treated with 0.6 or 2% glutaraldehyde within and between the two species. Using the subcutaneous model, we did not detect a difference in calcification potential between kangaroo and porcine aortic valves treated with either high or low concentrations of glutaraldehyde.

  12. Environmental and management influences on temporal variability of near saturated soil hydraulic properties.

    PubMed

    Bodner, G; Scholl, P; Loiskandl, W; Kaul, H-P

    2013-08-01

    Structural porosity is a decisive property for soil productivity and soil environmental functions. Hydraulic properties in the structural range vary over time in response to management and environmental influences. Although this is widely recognized, there are few field studies that determine dominant driving forces underlying hydraulic property dynamics. During a three year field experiment we measured temporal variability of soil hydraulic properties by tension infiltrometry. Soil properties were characterized by hydraulic conductivity, effective macroporosity and Kosugi's lognormal pore size distribution model. Management related influences comprised three soil cover treatment (mustard and rye vs. fallow) and an initial mechanical soil disturbance with a rotary harrow. Environmental driving forces were derived from meteorological and soil moisture data. Soil hydraulic parameters varied over time by around one order of magnitude. The coefficient of variation of soil hydraulic conductivity K(h) decreased from 69.5% at saturation to 42.1% in the more unsaturated range (- 10 cm pressure head). A slight increase in the Kosugi parameter showing pore heterogeneity was observed under the rye cover crop, reflecting an enhanced structural porosity. The other hydraulic parameters were not significantly influenced by the soil cover treatments. Seedbed preparation with a rotary harrow resulted in a fourfold increase in macroporosity and hydraulic conductivity next to saturation, and homogenized the pore radius distribution. Re-consolidation after mechanical loosening lasted over 18 months until the soil returned to its initial state. The post-tillage trend of soil settlement could be approximated by an exponential decay function. Among environmental factors, wetting-drying cycles were identified as dominant driving force explaining short term hydraulic property changes within the season (r(2) = 0.43 to 0.59). Our results suggested that beside considering average

  13. Detection of Calcifications In Vivo and Ex Vivo After Brain Injury in Rat Using SWIFT

    PubMed Central

    Lehto, Lauri Juhani; Sierra, Alejandra; Corum, Curtis Andrew; Zhang, Jinjin; Idiyatullin, Djaudat; Pitkänen, Asla; Garwood, Michael; Gröhn, Olli

    2012-01-01

    Calcifications represent one component of pathology in many brain diseases. With MRI, they are most often detected by exploiting negative contrast in magnitude images. Calcifications are more diamagnetic than tissue, leading to a magnetic field disturbance that can be seen in phase MR images. Most phase imaging studies use gradient recalled echo based pulse sequences. Here, the phase component of SWIFT, a virtually zero acquisition delay sequence, was used to detect calcifications ex vivo and in vivo in rat models of status epilepticus and traumatic brain injury. Calcifications were detected in phase and imaginary SWIFT images based on their dipole like magnetic field disturbances. In magnitude SWIFT images, calcifications were distinguished as hypointense and hyperintense. Hypointense calcifications showed large crystallized granules with few surrounding inflammatory cells, while hyperintense calcifications contained small granules with the presence of more inflammatory cells. The size of the calcifications in SWIFT magnitude images correlated with that in Alizarin stained histological sections. Our data indicate that SWIFT is likely to better preserve signal in the proximity of a calcification or other field perturber in comparison to gradient echo due to its short acquisition delay and broad excitation bandwidth. Furthermore, a quantitative description for the phase contrast near dipole magnetic field inhomogeneities for the SWIFT pulse sequence is given. In vivo detection of calcifications provides a tool to probe the progression of pathology in neurodegenerative diseases. In particular, it appears to provide a surrogate marker for inflammatory cells around the calcifications after brain injury. PMID:22425671

  14. Photo-physical properties of 2-(1-ethynylpyrene)-adenosine: influence of hydrogen bonding on excited state properties.

    PubMed

    Trojanowski, P; Plötner, J; Grünewald, C; Graupner, F F; Slavov, C; Reuss, A J; Braun, M; Engels, J W; Wachtveitl, J

    2014-07-21

    The photo-physical properties of 2-(1-ethynylpyrene)-adenosine (PyA), a fluorescent probe for RNA dynamics, were examined by solvation studies. The excited-state dynamics display the influence of the vicinity on the spectral features. Combining improved transient absorption and streak camera measurements along with a new analysis method provide a detailed molecular picture of the photophysics. After intramolecular vibrational energy redistribution (IVR), two distinct states are observed. Solvent class (protic/aprotic) and permittivity strongly affect the properties of these states and their population ratio. As a result their emission spectrum is altered, while the fluorescence quantum yield and the overall lifetime remain nearly unchanged. Consequently, the hitherto existing model of the photophysics is herein refined and extended. The findings can serve as basis for improving the information content of measurements with PyA as a label in RNA. PMID:24894337

  15. A new concept for melatonin deficit: on pineal calcification and melatonin excretion.

    PubMed

    Kunz, D; Schmitz, S; Mahlberg, R; Mohr, A; Stöter, C; Wolf, K J; Herrmann, W M

    1999-12-01

    Even though exogenous melatonin has proven to influence sleep and circadian parameters, low endogenous melatonin is not related to sleep disturbances, nor does it predict response to melatonin replacement therapy. In this manuscript, we present a new concept towards a definition of a melatonin deficit. The purpose of the study was to introduce a marker for an intra-individual decrease in melatonin production. Therefore, we developed a method to quantify the degree of pineal calcification (DOC) using cranial computed tomography. Combining pineal DOC with the organs's size, we estimated the uncalcified pineal gland volume. This estimation was positively and significantly associated with 6-sulfatoxymelatonin (aMT6s), collected over 24 hours in urine, in 26 subjects. Data yielded evidence that the decline in aMT6s excretion with age can be sufficiently explained by an increased pineal calcification. These results suggest that DOC might be useful as an indicator of an intra-individual, decreased capability of the pineal gland to produce melatonin. DOC might prove to be a response-marker for melatonin replacement therapy and a vulnerability marker of the circadian timing system. PMID:10633482

  16. Net community production and calcification from 7 years of NOAA Station Papa Mooring measurements

    NASA Astrophysics Data System (ADS)

    Fassbender, Andrea J.; Sabine, Christopher L.; Cronin, Meghan F.

    2016-02-01

    Seven years of near-continuous observations from the Ocean Station Papa (OSP) surface mooring were used to evaluate drivers of marine carbon cycling in the eastern subarctic Pacific. Processes contributing to mixed layer carbon inventory changes throughout each deployment year were quantitatively assessed using a time-dependent mass balance approach in which total alkalinity and dissolved inorganic carbon were used as tracers. By using two mixed layer carbon tracers, it was possible to isolate the influences of net community production (NCP) and calcification. Our results indicate that the annual NCP at OSP is 2 ± 1 mol C m-2 yr-1 and the annual calcification is 0.3 ± 0.3 mol C m-2 yr-1. Piecing together evidence for potentially significant dissolved organic carbon cycling in this region, we estimate a particulate inorganic carbon to particulate organic carbon ratio between 0.15 and 0.25. This is at least double the global average, adding to the growing evidence that calcifying organisms play an important role in carbon export at this location. These results, coupled with significant seasonality in the NCP, suggest that carbon cycling near OSP may be more complex than previously thought and highlight the importance of continuous observations for robust assessments of biogeochemical cycling.

  17. Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera.

    PubMed

    Prazeres, Martina; Uthicke, Sven; Pandolfi, John M

    2015-03-22

    Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii, we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity.

  18. Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera

    PubMed Central

    Prazeres, Martina; Uthicke, Sven; Pandolfi, John M.

    2015-01-01

    Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii, we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity. PMID:25694619

  19. Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera.

    PubMed

    Prazeres, Martina; Uthicke, Sven; Pandolfi, John M

    2015-03-22

    Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii, we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity. PMID:25694619

  20. The influence of Reynolds numbers on resistance properties of jet pumps

    NASA Astrophysics Data System (ADS)

    Geng, Q.; Zhou, G.; Li, Q.

    2014-01-01

    Jet pumps are widely used in thermoacoustic Stirling heat engines and pulse tube cryocoolers to eliminate the effect of Gedeon streaming. The resistance properties of jet pumps are principally influenced by their structures and flow regimes which are always characterized by Reynolds numbers. In this paper, the jet pump of which cross section contracts abruptly is selected as our research subject. Based on linear thermoacoustic theory, a CFD model is built and the oscillating flow of the working gas is simulated and analyzed with different Reynolds numbers in the jet pump. According to the calculations, the influence of different structures and Reynolds numbers on the resistance properties of the jet pump are analyzed and presented. The results show that Reynolds numbers have a great influence on the resistance properties of jet pumps and some empirical formulas which are widely used are unsuitable for oscillating flow with small Reynolds numbers. This paper provides a more comprehensive understanding on resistance properties of jet pumps with oscillating flow and is significant for the design of jet pumps in practical thermoacoustic engines and refrigerators.

  1. The influence of Reynolds numbers on resistance properties of jet pumps

    SciTech Connect

    Geng, Q.; Zhou, G.; Li, Q.

    2014-01-29

    Jet pumps are widely used in thermoacoustic Stirling heat engines and pulse tube cryocoolers to eliminate the effect of Gedeon streaming. The resistance properties of jet pumps are principally influenced by their structures and flow regimes which are always characterized by Reynolds numbers. In this paper, the jet pump of which cross section contracts abruptly is selected as our research subject. Based on linear thermoacoustic theory, a CFD model is built and the oscillating flow of the working gas is simulated and analyzed with different Reynolds numbers in the jet pump. According to the calculations, the influence of different structures and Reynolds numbers on the resistance properties of the jet pump are analyzed and presented. The results show that Reynolds numbers have a great influence on the resistance properties of jet pumps and some empirical formulas which are widely used are unsuitable for oscillating flow with small Reynolds numbers. This paper provides a more comprehensive understanding on resistance properties of jet pumps with oscillating flow and is significant for the design of jet pumps in practical thermoacoustic engines and refrigerators.

  2. Observations of Three-Dimensional Radiative Effects that Influence Satellite Retrievals of Cloud Properties

    NASA Technical Reports Server (NTRS)

    Varnai, Tamas; Marshak, Alexander; Lau, William K. M. (Technical Monitor)

    2001-01-01

    This paper examines three-dimensional (3D) radiative effects, which arise from horizontal radiative interactions between areas that have different cloud properties. Earlier studies have argued that these effects can cause significant uncertainties in current satellite retrievals of cloud properties, because the retrievals rely on one-dimensional (1D) theory and do not consider the effects of horizontal changes in cloud properties. This study addresses two questions: which retrieved cloud properties are influenced by 3D radiative effects, and where 3D effects tend to occur? The influence of 3D effects is detected from the wayside illumination and shadowing make clouds appear asymmetric: Areas appear brighter if the cloud top surface is tilted toward, rather than away from, the Sun. The analysis of 30 images by the Moderate Resolution Imaging Spectroradiometer (MODIS) reveals that retrievals of cloud optical thickness and cloud water content are most influenced by 3D effects, whereas retrievals of cloud particle size are much less affected. The results also indicate that while 3D effects are strongest at cloud edges, cloud top variability in cloud interiors, even in overcast regions, also produces considerable 3D effects. Finally, significant 3D effects are found in a wide variety of situations, ranging from thin clouds to thick ones and from low clouds to high ones.

  3. Influence of x-ray radiation on the properties of magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Yu, M.; Fu, J.; Ju, B. X.; Zheng, X.; Choi, S. B.

    2013-12-01

    In this work, the influence of x-ray radiation on the properties of magnetorheological elastomers (MREs) was experimentally investigated. Five MRE samples with the same composition were prepared, and then were irradiated by an x-ray detection machine, with different radiation doses. The microstructures of samples before and after x-ray irradiation were observed by using scanning electron microscopy. The dynamic mechanical properties of all samples were investigated under different magnetic flux densities. The experimental results indicated that the x-rays had a great impact on the properties of MRE. Due to the x-ray radiation, two kinds of radiation-induced effects were generated in the MRE, which were radiation-induced crosslinking and radiation-induced degradation. Based on the influence of the radiation-induced effects on MRE, the initial modulus of the MRE was increased by the radiation-induced crosslinking effect, but the MR effect of the MRE decreased. While the MRE began to degrade, the MR effect of the MRE exhibited a large increasing trend with the increase of the x-ray radiation dose. In addition, the damping property of the MRE was also influenced greatly by the x-ray radiation, and the loss factor of the MRE was increased dramatically first and then decreased under x-ray irradiation. On the basis of these results, this study may provide a good guideline for developing various applications of MREs.

  4. Spent nuclear fuel and residential property values : the influence of proximity, visual cues and public information.

    SciTech Connect

    Clark, D. E.; Allison, T.; Decision and Information Sciences; Marquette Univ.

    1999-10-01

    This article examines whether public knowledge of spent fuel storage at nuclear power plants, and any local adverse risk perceptions that may have occurred, affect the sale price of single-family residential properties. We present evidence from the Rancho Seco, California, plant on residential property values using an hedonic modeling framework. We include a large number of control variables, data with a high level of spatial detail and a number of public information variables in order to model property market effects within a fifteen mile radius of the plant. Our findings indicate that proximity and visual reminders of the plant have some influence on local property markets, and that there is a small media coverage effect on single-family home sale prices.

  5. Tensile properties influencing variables in eutectic Al-Si casting alloys

    SciTech Connect

    Hafiz, M.F. . Dept. of Mechanical Engineering); Kobayashi, Toshiro . Dept. of Production Systems Engineering)

    1994-09-15

    Efforts to identify and characterize the physical properties of aluminum castings alloys are envisaged to lead to a new guideline from which the mechanical behavior of these alloys can be accurately predicted. For aluminum-silicon (Al-Si) casting alloys the tensile properties of a specific composition are observed to vary depending on the production parameters. The difference in the tensile properties appears to be mainly due to the microstructural features concomitant with the imposed production parameters. The present study aims to identify, quantitatively, the tensile properties influencing variables in high purity eutectic Al-Si casting alloy produced under a variety of solidification cooling rate with different strontium (Sr) additions, as a modifying agent. The correlation between the fracture characteristics and the microstructures has also been investigated.

  6. Sediment properties influencing the bioavailability of uranium to Chironomus dilutus larvae in spiked field sediments.

    PubMed

    Crawford, Sarah E; Liber, Karsten

    2016-04-01

    The partitioning of metals between dissolved and solid phases directly affects metal bioavailability to benthic invertebrates and is influenced by metal-binding properties of sediment phases. Little research has been done examining the effects of sediment properties on the bioavailability of uranium (U) to freshwater benthic invertebrates. In the present study, 18 field sediments with a wide range of properties (total organic carbon, fine fraction, cation exchange capacity, and iron content) were amended with the same concentrations of U to characterize the effects of these sediment properties on U bioavailability to freshwater midge, Chironomus dilutus. Bioaccumulation of U by C. dilutus larvae varied by over an order of magnitude when exposed to sediments spiked with 50 mg U kg(-1) d.w. (5-69 mg U kg(-1) d.w.) and 500 mg U kg(-1) d.w. (20-452 mg U kg(-1) d.w.), depending on the type of sediment. Variance in U bioaccumulation was best explained by differences in the cation exchange capacity, fine fraction (≤50 μm particle size), and Fe content of U-spiked sediment, with generated regression equations predicting observed bioaccumulation within a factor of two. The presented regression equations offer an easy-to-apply method for accounting for the influence of sediment properties on U bioavailability in freshwater sediment, with fine fraction being the single most practical variable. This research strongly supports that risk assessments and guidelines for U-contaminated sediments should not ignore the influence of sediment properties that can result in substantial differences in the bioaccumulation of U in benthic invertebrates. PMID:26802266

  7. Sediment properties influencing the bioavailability of uranium to Chironomus dilutus larvae in spiked field sediments.

    PubMed

    Crawford, Sarah E; Liber, Karsten

    2016-04-01

    The partitioning of metals between dissolved and solid phases directly affects metal bioavailability to benthic invertebrates and is influenced by metal-binding properties of sediment phases. Little research has been done examining the effects of sediment properties on the bioavailability of uranium (U) to freshwater benthic invertebrates. In the present study, 18 field sediments with a wide range of properties (total organic carbon, fine fraction, cation exchange capacity, and iron content) were amended with the same concentrations of U to characterize the effects of these sediment properties on U bioavailability to freshwater midge, Chironomus dilutus. Bioaccumulation of U by C. dilutus larvae varied by over an order of magnitude when exposed to sediments spiked with 50 mg U kg(-1) d.w. (5-69 mg U kg(-1) d.w.) and 500 mg U kg(-1) d.w. (20-452 mg U kg(-1) d.w.), depending on the type of sediment. Variance in U bioaccumulation was best explained by differences in the cation exchange capacity, fine fraction (≤50 μm particle size), and Fe content of U-spiked sediment, with generated regression equations predicting observed bioaccumulation within a factor of two. The presented regression equations offer an easy-to-apply method for accounting for the influence of sediment properties on U bioavailability in freshwater sediment, with fine fraction being the single most practical variable. This research strongly supports that risk assessments and guidelines for U-contaminated sediments should not ignore the influence of sediment properties that can result in substantial differences in the bioaccumulation of U in benthic invertebrates.

  8. Influence of magnetostimulation therapy on rheological properties of blood in neurological patients.

    PubMed

    Marcinkowska-Gapińska, Anna; Kowal, Piotr

    2016-01-01

    The aim of the study is to test the influence of in vivo magnetostimulation on the rheological properties of blood in neurological patients. Blood circulation in the body depends both on the mechanical properties of the circulatory system and on the physical and physicochemical properties of blood. The main factors influencing the rheological properties of blood are as follows: hematocrit, plasma viscosity, whole-blood viscosity, red cells aggregability, deformability, and the ability of red cells to orient in the flow. The blood samples were collected from neurological patients with pain. Blood samples were collected twice from each patient, that is, before the magnetostimulation and immediately after the therapy. For each blood sample, the hematocrit value was measured using the standard method. Plasma viscosity and whole-blood viscosity were measured by means of a rotary-oscillating rheometer Contraves LS40. Magnetic field was generated by the instrument Viofor JPS® and the magnetostimulation treatments were performed using M1P2 and M1P3 programs. The analysis of the results included estimation of the hematocrit value (Hct), plasma viscosity (ηp), whole-blood viscosity and rheological parameters of Quemada's model: k0, k∞, γ'c. Plasma viscosity values were obtained from the shear rate dependence of shear stress using the linear regression method. The results obtained in the study suggest that the blood rheological properties change in accord with applied magnetostimulation program. PMID:27014934

  9. Influence of Physicochemical Properties of Silver Nanoparticles on Mast Cell Activation and Degranulation

    PubMed Central

    Aldossari, Abdullah A.; Shannahan, Jonathan H.; Podila, Ramakrishna; Brown, Jared M.

    2014-01-01

    Silver nanoparticles (AgNPs) are increasingly being incorporated into products for their antimicrobial properties. This has resulted in increased human exposures and the possibility of adverse health effects. Mast cells orchestrate allergic immune responses through degranulation and release of pre-formed mediators. Little data exists on understanding interactions of AgNPs with mast cells and the properties that influence activation and degranulation. Using bone marrow-derived mast cells and AgNPs of varying physicochemical properties we tested the hypothesis that AgNP physicochemical properties influence mast cell degranulation and osteopontin production. AgNPs evaluated included spherical 20 nm and 110 nm suspended in either polyvinylpyrrolidone (PVP) or citrate, Ag plates suspended in PVP of diameters between 40–60 nm or 100–130 nm, and Ag nanowires suspended in PVP with thicknesses <100 nm and length up to 2 microns. Mast cell responses were found to be dependent on the physicochemical properties of the AgNP. Further, we determined a role for scavenger receptor B1 in AgNP-induced mast cell responses. Mast cell degranulation was not dependent on AgNP dissolution but was prevented by tyrosine kinsase inhibitor pretreatment. This study suggests that exposure to AgNPs may elicit adverse mast cell responses that could contribute to the initiation or exacerbation of allergic disease. PMID:25458489

  10. Influence of concentration modifier on the structure and functional properties of aluminum oxyhydroxide modified

    NASA Astrophysics Data System (ADS)

    Shiyan, L. N.; Gryaznova, E. N.; Galanov, S. I.; Sidorova, O. I.

    2016-02-01

    Studying the properties of nanomaterials is an important task, but nanomaterials with desired properties is a promising direction. The aim of this work is to investigate the influence of the value of the concentration of the modifier (ions Mn2+) on the structural and functional properties of modified aluminum oxyhydroxide. In this paper, using methods such as the X-ray diffraction studies, differential thermal analysis, electron microscopy, chromatography. The paper found that increasing the concentration of the modifier result in significant changes in the morphology, the appearance of metallic aluminum, which is well seen on X-ray data samples. The influence of thermal effects on a modified aluminum oxyhydroxide argon. Set the phase transition temperatures in the synthesized samples. It is shown that with increasing sodeozhaniya manganese in the composition of the synthesized samples decreases the value of specific surface area. Study of the functional properties showed that the synthesized material has catalytic properties in the oxidation of methane. It is shown that the effective sample is a sample with a manganese content of 2.7 wt. %. By XRD results calcined in air samples modified aluminum oxyhydroxide was shown that only in the sample with a manganese content of 2.7 wt. % MnAl2O4 phase is formed, which is catalytically active phase.

  11. Influence of sputtering power on the optical properties of ITO thin films

    SciTech Connect

    K, Aijo John; M, Deepak T, Manju; Kumar, Vineetha V.

    2014-10-15

    Tin doped indium oxide films are widely used in transparent conducting coatings such as flat panel displays, crystal displays and in optical devices such as solar cells and organic light emitting diodes due to the high electrical resistivity and optical transparency in the visible region of solar spectrum. The deposition parameters have a commendable influence on the optical and electrical properties of the thin films. In this study, ITO thin films were prepared by RF magnetron sputtering. The properties of the films prepared under varying sputtering power were compared using UV- visible spectrophotometry. Effect of sputtering power on the energy band gap, absorption coefficient and refractive index are investigated.

  12. Influence of magnetic and acoustic treatment of superplasticizer solutions on the properties of portland cement concretes

    NASA Astrophysics Data System (ADS)

    Belous, N. Kh.; Azharonok, V. V.; Rodtsevich, S. P.; Koshevar, V. D.; Goncharik, S. V.; Chubrik, N. I.; Orlovich, A. I.; Rubannik, V. V.

    2012-05-01

    We have investigated the influence of the regimes of high-frequency magnetic-impulse and acoustic action on the physicochemical properties of water solutions of polycarboxylate superplasticizers and technological indices of fine concretes plasticized by them. The dependences of technological properties of concretes on the concentration of water solutions of the superplasticizers, the content of impurity ions in the water used for dilution, and the conditions of acousto-radiowave treatment have been determined. The regimes of activation of superplasticizer solutions, which permit increasing the mobility and keeping quality of concrete and solution mixes tempered with water and the density and strength of fine concretes formed from them, have been established.

  13. The influence of halogen substituents on the biological properties of sulfur-containing flavonoids.

    PubMed

    Bahrin, Lucian Gabriel; Sarbu, Laura Gabriela; Hopf, Henning; Jones, Peter G; Babii, Cornelia; Stefan, Marius; Birsa, Mihail Lucian

    2016-07-15

    A series of halogen-substituted tricyclic flavonoids containing a 1,3-dithiol-2-ylium moiety has been synthesized from the corresponding 3-dithiocarbamic flavanones. The influence of halogen substituents on the antibacterial properties of the tricyclic flavonoids has been investigated against Staphylococcus aureus and Escherichia coli. On going from fluorine to iodine, these compounds exhibit good to excellent inhibitory properties against both Gram-positive and Gram-negative pathogens. These results suggest that size is the main factor for the change in potency rather than polarity/electronics. PMID:27259400

  14. Influence of pre-stress fields on electric properties of semiconductor nanowires

    SciTech Connect

    Zhu, Linli

    2015-03-10

    The effects of pre-stress field on the electric properties such as electron-acoustic phonon interaction and mobility are investigated for a rectangular silicon nanowire. The continuum elastic model is employed to calculate the spatially confined phonon dispersion relation. The electron-acoustic phonon scattering rate and the carrier mobility are obtained for stressed silicon nanowire. The numerical results show that the pre-stress field has a significant influence on the phonon properties, leading to completely altering the electron-acoustic phonon interaction. Under the tensile (compressive) pre-stress, the carrier mobility is reduced (enhanced) that is sensitive to the strength of corresponding stress fields.

  15. Influence of sputtering power on the optical properties of ITO thin films

    NASA Astrophysics Data System (ADS)

    K, Aijo John; Kumar, Vineetha V.; M, Deepak; T, Manju

    2014-10-01

    Tin doped indium oxide films are widely used in transparent conducting coatings such as flat panel displays, crystal displays and in optical devices such as solar cells and organic light emitting diodes due to the high electrical resistivity and optical transparency in the visible region of solar spectrum. The deposition parameters have a commendable influence on the optical and electrical properties of the thin films. In this study, ITO thin films were prepared by RF magnetron sputtering. The properties of the films prepared under varying sputtering power were compared using UV- visible spectrophotometry. Effect of sputtering power on the energy band gap, absorption coefficient and refractive index are investigated.

  16. Direct Synthesis and Morphological Characterization of Gold-Dendrimer Nanocomposites Prepared Using PAMAM Succinamic Acid Dendrimers: Preliminary Study of the Calcification Potential

    PubMed Central

    Vasile, E.; Serafim, A.; Petre, D.; Giol, D.; Dubruel, P.; Iovu, H.; Stancu, I. C.

    2014-01-01

    Gold-dendrimer nanocomposites were obtained for the first time by a simple colloidal approach based on the use of polyamidoamine dendrimers with succinamic acid terminal groups and dodecanediamine core. Spherical and highly crystalline nanoparticles with dimensions between 3 nm and 60 nm, and size-polydispersity depending on the synthesis conditions, have been generated. The influence of the stoichiometric ratio and the structural and architectural features of the dendrimers on the properties of the nanocomposites has been described. The self-assembling behaviour of these materials produces gold-dendrimer nanostructured porous networks with variable density, porosity, and composition. The investigations of the reaction systems, by TEM, at two postsynthesis moments, allowed to preliminary establish the control over the properties of the nanocomposite products. Furthermore, this study allowed better understanding of the mechanism of nanocomposite generation. Impressively, in the early stages of the synthesis, the organization of gold inside the dendrimer molecules has been evidenced by micrographs. Growth and ripening mechanisms further lead to nanoparticles with typical characteristics. The potential of such nanocomposite particles to induce calcification when coating a polymer substrate was also investigated. PMID:24600316

  17. Sequence and domain arrangements influence mechanical properties of elastin-like polymeric elastomers.

    PubMed

    Miao, Ming; Sitarz, Eva; Bellingham, Catherine M; Won, Emily; Muiznieks, Lisa D; Keeley, Fred W

    2013-06-01

    Elastin is the polymeric, extracellular matrix protein that provides properties of extensibility and elastic recoil to large arteries, lung parenchyma, and other tissues. Elastin assembles by crosslinking through lysine residues of its monomeric precursor, tropoelastin. Tropoelastin, as well as polypeptides based on tropoelastin sequences, undergo a process of self-assembly that aligns lysine residues for crosslinking. As a result, both the full-length monomer as well as elastin-like polypeptides (ELPs) can be made into biomaterials whose properties resemble those of native polymeric elastin. Using both full-length human tropoelastin (hTE) as well as ELPs, we and others have previously reported on the influence of sequence and domain arrangements on self-assembly properties. Here we investigate the role of domain sequence and organization on the tensile mechanical properties of crosslinked biomaterials fabricated from ELP variants. In general, substitutions in ELPs involving similiar domain types (hydrophobic or crosslinking) had little effect on mechanical properties. However, modifications altering either the structure or the characteristic sequence style of these domains had significant effects on such properties. In addition, using a series of deletion and replacement constructs for full-length hTE, we provide new insights into the role of conserved domains of tropoelastin in determining mechanical properties. PMID:23529691

  18. Influence Of Ambient Light On The "Visual" Sensitometric Properties Of, And Detail Perception On, A Radiograph

    NASA Astrophysics Data System (ADS)

    Bollen, Romain; Vranckx, Jean

    1981-07-01

    Lack of perception at high densities on radiographs and the influence of viewing conditions on it are well known. This lack may be caused by blinding effects, by high visual noise at low light intensities or by a third phenomenon i.e. the dependence of the sensitometric properties of film on viewing conditions, which is analyzed in this paper. Reflection of ambient light by the film mainly lowers dramatically high densities and film contrast at these densities. Sensitometric curves of several films were measured under different viewing conditions by means of a telescopic photometer. The curves also can be deduced from curves measured by a regular densitometer when the optical properties of the film, the ambient light level and the light intensity of the negatoscope are known. The influence of the phenomenon under typical viewing conditions for the Curix MR4-film is demonstrated by means of sensitometric- and perceptibility-curves.

  19. Influence of perennial plants on chemical properties of arid calcareous soils in Iran

    SciTech Connect

    Karimian, N.; Razmi, K. )

    1990-10-01

    The authors conducted a study in Bajgah to determine the influence of perennial plants on some selected properties of soils formed on the highly calcareous parent material. The major plant genera were determined to be Agropyron, Artemisia, Astragalus, Dianthus, Eryngium, Peganum, Polygonum, Stipa, and Thymus. Tops of plants genera were found to be significantly different in ash, N, P, K, Ca, Mg, Na, Mn, Zn, and Cu; the concentration of Fe was not significantly different. The authors found the plants to differ significantly in their influence on soil properties. Peganum caused an accumulation of organic matter (OM) as high as 7% in the soil, in an environment where the soils typically contain less than 1% OM. Soil concentrations of P, K, Mn, Zn, and Cu were also found to vary significantly beneath different plant genera. They suggest these differences in OM accumulation were caused by plant litter. Concentration of Fe in the soils formed beneath different plant genera was statistically unchanged.

  20. Influence of sterilisation methods on collagen-based devices stability and properties.

    PubMed

    Delgado, Luis M; Pandit, Abhay; Zeugolis, Dimitrios I

    2014-05-01

    Sterilisation is essential for any implantable medical device in order to prevent infection in patients. The selection of the most appropriate sterilisation method depends on the nature and the physical state of the material to be sterilised; the influence of the sterilisation method on the properties of the device; and the type of the potential contaminant. In this context, herein we review the influence of ethylene oxide, γ-irradiation, e-beam irradiation, gas plasma, peracetic acid and ethanol on structural, biomechanical, biochemical and biological properties of collagen-based devices. Data to-date demonstrate that chemical approaches are associated with cytotoxicity, whilst physical methods are associated with degradation, subject to the device physical characteristics. Thus, the sterilisation method of choice is device dependent. PMID:24654928

  1. Influence of viscoelastic property on laser-generated surface acoustic waves in coating-substrate systems

    SciTech Connect

    Sun Hongxiang; Zhang Shuyi; Xu Baiqiang

    2011-04-01

    Taking account of the viscoelasticity of materials, the pulsed laser generation of surface acoustic waves in coating-substrate systems has been investigated quantitatively by using the finite element method. The displacement spectra of the surface acoustic waves have been calculated in frequency domain for different coating-substrate systems, in which the viscoelastic properties of the coatings and substrates are considered separately. Meanwhile, the temporal displacement waveforms have been obtained by applying inverse fast Fourier transforms. The numerical results of the normal surface displacements are presented for different configurations: a single plate, a slow coating on a fast substrate, and a fast coating on a slow substrate. The influences of the viscoelastic properties of the coating and the substrate on the attenuation of the surface acoustic waves have been studied. In addition, the influence of the coating thickness on the attenuation of the surface acoustic waves has been also investigated in detail.

  2. Beyond the Alphabet Soup: Molecular Properties of Aerosol Components Influence Optics. (Invited)

    NASA Astrophysics Data System (ADS)

    Thompson, J. E.

    2013-12-01

    Components within atmospheric aerosols exhibit almost every imaginable model of chemical bonding and physical diversity. The materials run the spectrum from crystalline to amorphous, covalent to ionic, and have varying viscosities, phase, and hygroscopicity. This seminar will focus on the molecular properties of materials that influence the optical behavior of aerosols. Special focus will be placed on the polarizability of materials, hygroscopic growth, and particle phase.

  3. The influence of impurities and planar defects on the infrared properties of silicon carbide films

    SciTech Connect

    Rajasekhara, S.; Ferreira, P. J.; Kovar, D.; Neuner, B. H. III; Shvets, G.; Zorman, C. A.; Jegenyes, N.; Ferro, G.

    2011-05-09

    Two cubic, single crystal silicon carbide (3C-SiC) films with similar thickness are shown to exhibit significantly different optical properties at mid-infrared wavelengths. Depth profiling by time-of-flight secondary ion mass spectroscopy indicates that these two films have substantially different n-type impurity concentrations that are responsible for the observed differences in optical absorption. The influence of impurities manifests as substantially different planar defect morphologies.

  4. Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method

    NASA Astrophysics Data System (ADS)

    Bobadilla, L. F.; García, C.; Delgado, J. J.; Sanz, O.; Romero-Sarria, F.; Centeno, M. A.; Odriozola, J. A.

    2012-11-01

    The influence of PVP on the magnetic properties of NiSn nanoparticles prepared by polyol method has been studied. NiSn nanoparticles exhibit superparamagnetic behavior although there is a ferromagnetic contribution due to particles agglomerated below the blocking temperature. The particle size is controlled by the addiction of PVP in varying amounts. The addition of PVP also favours the particles isolation, narrow the particle size distribution and decrease the interparticle interaction strength increasing the superparamagnetic contribution.

  5. Grazing season and forage type influence goat milk composition and rennet coagulation properties.

    PubMed

    Inglingstad, R A; Steinshamn, H; Dagnachew, B S; Valenti, B; Criscione, A; Rukke, E O; Devold, T G; Skeie, S B; Vegarud, G E

    2014-01-01

    Two different types of pasture (cultivated and rangeland) and 2 different hay qualities (high and low quality) were examined for their effects on goat milk composition and rennet coagulation properties. Furthermore, the effect of dietary treatments in both the early and late grazing season was studied. As lactation stage is known to influence milk composition, the goats in the early and late grazing season were in the same lactation stage at the start of the experiment. The milk composition was influenced both by dietary treatment and season. Milk from goats on pasture was superior to those on hay by containing a higher content of protein and casein, and the goats on cultivated pasture had the highest milk yield. Casein composition was significantly influenced by forage treatment. Goats grazing on cultivated pasture had higher contents of αs1-casein and also of κ-casein compared with the other treatments, whereas goats grazing on rangeland had the highest content of β-casein. Factors such as milk yield, casein micelle size, αs2-casein, and calcium content were reduced in late compared with early season. More favorable rennet coagulation properties were achieved in milk from the early grazing season, with shorter firming time and higher curd firmness compared with milk from the late grazing season, but the firming time and curd firmness were not prominently influenced by forage treatment. The content of αs2-casein and calcium in the milk affected the firming time and the curd firmness positively. The influence of season and forage treatment on especially milk yield, casein content, and rennet coagulation properties is of economic importance for both the dairy industry and goat milk farmers. PMID:24704223

  6. The Impact of Different Amounts of Calcium Intake on Bone Mass and Arterial Calcification in Ovariectomized Rats.

    PubMed

    Agata, Umon; Park, Jong-Hoon; Hattori, Satoshi; Aikawa, Yuki; Kakutani, Yuya; Ezawa, Ikuko; Akimoto, Takayuki; Omi, Naomi

    2015-01-01

    Reduced estrogen secretion and low calcium (Ca) intake are risk factors for bone loss and arterial calcification in female rodents. To evaluate the effects of Ca intake at different amounts on bone mass changes and arterial calcification, 8-wk-old female Wistar rats were randomly placed in ovariectomized (OVX) control and OVX with vitamin D3 plus nicotine (VDN) treatment groups. The OVX with VDN rats were then divided into six groups to receive different amounts of Ca in their diets: 0.01%, 0.1%, 0.3%, 0.6%, 1.2%, or 2.4% Ca. After 8 wk of administration, low Ca intake groups with 0.01% and 0.1% Ca diets had significantly reduced bone mineral density (BMD) and bone mechanical properties as compared with those of the other groups, whereas high Ca intake groups with 1.2% and 2.4% Ca diets showed no differences as compared with the 0.6% Ca intake group. For both the 0.01% and 2.4% Ca intake groups, Ca levels in their thoracic arteries were significantly higher as compared with those of the 0.6% Ca diet group, and that was highly correlated with serum PTH levels. An increase in relative BMP-2 mRNA expression in the arterial tissues of the 0.01% and 2.4% Ca diet groups was also observed. These results suggested that extremely low Ca intake during periods of estrogen deficiency may be a possible risk for the complications of reduced BMD and arterial calcification and that extremely high Ca intake may promote arterial calcification with no changes in BMD.

  7. Insights on the Optical Properties of Estuarine DOM – Hydrological and Biological Influences

    PubMed Central

    Santos, Luísa; Pinto, António; Filipe, Olga; Cunha, Ângela; Santos, Eduarda B. H.

    2016-01-01

    Dissolved organic matter (DOM) in estuaries derives from a diverse array of both allochthonous and autochthonous sources. In the estuarine system Ria de Aveiro (Portugal), the seasonality and the sources of the fraction of DOM that absorbs light (CDOM) were inferred using its optical and fluorescence properties. CDOM parameters known to be affected by aromaticity and molecular weight were correlated with physical, chemical and meteorological parameters. Two sites, representative of the marine and brackish water zones of the estuary, and with different hydrological characteristics, were regularly surveyed along two years, in order to determine the major influences on CDOM properties. Terrestrial-derived compounds are the predominant source of CDOM in the estuary during almost all the year and the two estuarine zones presented distinct amounts, as well as absorbance and fluorescence characteristics. Freshwater inputs have major influence on the dynamics of CDOM in the estuary, in particular at the brackish water zone, where accounted for approximately 60% of CDOM variability. With a lower magnitude, the biological productivity also impacted the optical properties of CDOM, explaining about 15% of its variability. Therefore, climate changes related to seasonal and inter-annual variations of the precipitation amounts might impact the dynamics of CDOM significantly, influencing its photochemistry and the microbiological activities in estuarine systems. PMID:27195702

  8. Influence of the dynamic ergodic divertor on transport properties in TEXTOR

    NASA Astrophysics Data System (ADS)

    Finken, K. H.; Unterberg, B.; Xu, Y.; Abdullaev, S. S.; Jakubowski, M.; Lehnen, M.; de Bock, M. F. M.; Bozhenkov, S.; Brezinsek, S.; Busch, C.; Classen, I. G. J.; Coenen, J. W.; Harting, D.; von Hellermann, M.; Jachmich, S.; Jaspers, R. J. E.; Kikuchi, Y.; Krämer-Flecken, A.; Liang, Y.; Mitri, M.; Peleman, P.; Pospieszczyk, A.; Reiser, D.; Reiter, D.; Samm, U.; Schega, D.; Schmitz, O.; Soldatov, S.; Van Schoor, M.; Vergote, M.; Weynants, R. R.; Wolf, R.; Zimmermann, O.; TEXTOR Team

    2007-07-01

    Experiments to investigate transport properties under the influence of the dynamic ergodic divertor (DED) on TEXTOR are discussed. Relativistic runaway electrons are applied for studying transport properties of ergodization such as enhanced runaway loss. The ergodization causes an enhanced loss rate; this loss is higher for low relativistic electrons than for highly relativistic ones, in good agreement with particle orbit mapping. Edge transport can be controlled by the DED perturbation: in limiter H-mode plasmas ELM-like particle and heat bursts associated with the formation of enhanced edge pressure gradients are mitigated in the 6/2 configuration on the expense of a reduced pedestal height. Finally, the plasma is driven back to L-mode under the influence of the magnetic perturbation. In the 3/1 configuration the onset of tearing modes limits the possibility to affect edge transport. A mode of spontaneous density built-up has been found for the TEXTOR-DED as well. This mode is in particular strong for an inward shifted plasma; the built-up has a resonant character with respect to q(a). Langmuir probe measurements with two probe arrays show a strong influence of the magnetic ergodization on both the edge plasma equilibrium and fluctuation parameters. In particular, in the ergodic zone the turbulence properties and turbulence-driven flux are profoundly modified.

  9. Insights on the Optical Properties of Estuarine DOM - Hydrological and Biological Influences.

    PubMed

    Santos, Luísa; Pinto, António; Filipe, Olga; Cunha, Ângela; Santos, Eduarda B H; Almeida, Adelaide

    2016-01-01

    Dissolved organic matter (DOM) in estuaries derives from a diverse array of both allochthonous and autochthonous sources. In the estuarine system Ria de Aveiro (Portugal), the seasonality and the sources of the fraction of DOM that absorbs light (CDOM) were inferred using its optical and fluorescence properties. CDOM parameters known to be affected by aromaticity and molecular weight were correlated with physical, chemical and meteorological parameters. Two sites, representative of the marine and brackish water zones of the estuary, and with different hydrological characteristics, were regularly surveyed along two years, in order to determine the major influences on CDOM properties. Terrestrial-derived compounds are the predominant source of CDOM in the estuary during almost all the year and the two estuarine zones presented distinct amounts, as well as absorbance and fluorescence characteristics. Freshwater inputs have major influence on the dynamics of CDOM in the estuary, in particular at the brackish water zone, where accounted for approximately 60% of CDOM variability. With a lower magnitude, the biological productivity also impacted the optical properties of CDOM, explaining about 15% of its variability. Therefore, climate changes related to seasonal and inter-annual variations of the precipitation amounts might impact the dynamics of CDOM significantly, influencing its photochemistry and the microbiological activities in estuarine systems. PMID:27195702

  10. Moss Mediates the Influence of Shrub Species on Soil Properties and Processes in Alpine Tundra

    PubMed Central

    Williamson, Scott N.; Barrio, Isabel C.; Helgadóttir, Ágústa; HiK, David S.

    2016-01-01

    In tundra ecosystems, bryophytes influence soil processes directly and indirectly through interactions with overstory shrub species. We experimentally manipulated moss cover and measured seasonal soil properties and processes under two species of deciduous shrubs with contrasting canopy structures, Salix planifolia pulchra and Betula glandulosa-nana complex. Soil properties (seasonal temperature, moisture and C:N ratios) and processes (seasonal litter decomposition and soil respiration) were measured over twelve months. Shrub species identity had the largest influence on summer soil temperatures and soil respiration rates, which were higher under Salix canopies. Mosses were associated with lower soil moisture irrespective of shrub identity, but modulated the effects of shrubs on winter soil temperatures and soil C:N ratios so that moss cover reduced differences in soil winter temperatures between shrub species and reduced C:N ratios under Betula but not under Salix canopies. Our results suggest a central role of mosses in mediating soil properties and processes, with their influence depending on shrub species identity. Such species-dependent effects need to be accounted for when forecasting vegetation dynamics under ongoing environmental changes. PMID:27760156

  11. Influence of physical properties of carrier on the performance of dry powder inhalers.

    PubMed

    Peng, Tingting; Lin, Shiqi; Niu, Boyi; Wang, Xinyi; Huang, Ying; Zhang, Xuejuan; Li, Ge; Pan, Xin; Wu, Chuanbin

    2016-07-01

    Dry powder inhalers (DPIs) offer distinct advantages as a means of pulmonary drug delivery and have attracted much attention in the field of pharmaceutical science. DPIs commonly contain micronized drug particles which, because of their cohesiveness and strong propensity to aggregate, have poor aerosolization performance. Thus carriers with a larger particle size are added to address this problem. However, the performance of DPIs is profoundly influenced by the physical properties of the carrier, particularly their particle size, morphology/shape and surface roughness. Because these factors are interdependent, it is difficult to completely understand how they individually influence DPI performance. The purpose of this review is to summarize and illuminate how these factors affect drug-carrier interaction and influence the performance of DPIs. PMID:27471671

  12. Influence of side chain configuration on anti-inflammatory analgesic and anti-pyretic properties of 4-biphenylyl alkanoic acids.

    PubMed

    Tenconi, F; Barzaghi, F; Riva, M; Meli, A

    1976-04-01

    A study on the influence of the number of carbon atoms in the side chain as well as side chain configuration on some pharmacologic properties of 4-biphenylyl alkanoic acids is presented. Unlike the chemical structure dependent anti-inflammatory properties, mild analgesic and anti-pyretic properties were neither dependent upon number of carbon atoms nor side chain configuration. PMID:939325

  13. Low Florida coral calcification rates in the Plio-Pleistocene

    NASA Astrophysics Data System (ADS)

    Brachert, Thomas C.; Reuter, Markus; Krüger, Stefan; Klaus, James S.; Helmle, Kevin; Lough, Janice M.

    2016-08-01

    In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands often allow for reconstructions of annual extension ( = growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. This report presents the bulk density, extension rates and calcification rates of fossil reef corals which underwent minor diagenetic alteration only. The corals derive from unlithified shallow water carbonates of the Florida platform (south-eastern USA), which formed during four interglacial sea level highstands dated approximately 3.2, 2.9, 1.8, and 1.2 Ma in the mid-Pliocene to early Pleistocene. With regard to the preservation, the coral skeletons display smooth growth surfaces with minor volumes of marine aragonite cement within intra-skeletal porosity. Within the skeletal structures, voids are commonly present along centres of calcification which lack secondary cements. Mean extension rates were 0.44 ± 0.19 cm yr-1 (range 0.16 to 0.86 cm yr-1), mean bulk density was 0.96 ± 0.36 g cm-3 (range 0.55 to 1.83 g cm-3) and calcification rates ranged from 0.18 to 0.82 g cm-2 yr-1 (mean 0.38 ± 0.16 g cm-2 yr-1), values which are 50 % of modern shallow-water reef corals. To understand the possible mechanisms behind these low calcification rates, we compared the fossil calcification rates with those of modern zooxanthellate corals (z corals) from the Western Atlantic (WA) and Indo-Pacific calibrated against sea surface temperature (SST). In the fossil data, we found a widely analogous relationship with SST in z corals from the WA, i.e. density increases and extension rate decreases with increasing SST, but over a significantly larger

  14. Hilar cholangiocarcinoma with intratumoral calcification: A case report

    PubMed Central

    Inoko, Kazuho; Tsuchikawa, Takahiro; Noji, Takehiro; Kurashima, Yo; Ebihara, Yuma; Tamoto, Eiji; Nakamura, Toru; Murakami, Soichi; Okamura, Keisuke; Shichinohe, Toshiaki; Hirano, Satoshi

    2015-01-01

    This report describes a rare case of hilar cholangiocarcinoma with intratumoral calcification that mimicked hepatolithiasis. A 73-year-old man presented to a local hospital with a calcified lesion in the hepatic hilum. At first, hepatolithiasis was diagnosed, and he underwent endoscopic stone extraction via the trans-papillary route. This treatment strategy failed due to biliary stricture. He was referred to our hospital, and further examination suggested the existence of cholangiocarcinoma. He underwent left hepatectomy with caudate lobectomy and extrahepatic bile duct resection. Pathological examination revealed hilar cholangiocarcinoma with intratumoral calcification, while no stones were found. To the best of our knowledge, only one case of calcified hilar cholangiocarcinoma has been previously reported in the literature. Here, we report a rare case of calcified hilar cholangiocarcinoma and reveal its clinicopathologic features. PMID:26478684

  15. Low Florida coral calcification rates in the Plio-Pleistocene

    NASA Astrophysics Data System (ADS)

    Brachert, T. C.; Reuter, M.; Krüger, S.; Klaus, J. S.; Helmle, K.; Lough, J. M.

    2015-12-01

    In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands may be retained allowing for reconstructions of annual extension (= growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. Here we report the first data of calcification rates of fossil reef corals which escaped diagenetic alteration. The corals derive from unlithified shallow water carbonates of the Florida platform (southeastern USA), which formed during four interglacial sea level highstands dated 3.2, 2.9, 1.8, and 1.2 Ma in the mid Pliocene to early Pleistocene. With regard to the preservation, the coral skeletons display smooth growth surfaces with minor volumes of marine aragonite cement within intra-skeletal porosity. Within the skeletal structures, dissolution is minor along centers of calcification. Mean extension rates were 0.44 ± 0.19 cm yr-1 (range 0.16 to 0.86 cm yr-1) and mean bulk density was 0.86 ± 0.36 g cm-3 (range 0.55 to 1.22 g cm-3). Correspondingly, calcification rates ranged from 0.18 to 0.82 g cm-2 yr-1 (mean 0.38 ± 0.16 g cm-2 yr-1), values which are 50 % of modern shallow-water reef corals. To understand the possible mechanisms behind these low calcification rates, we compared the fossil calcification with modern zooxanthellate-coral (z-coral) rates from the Western Atlantic (WA) and Indo-Pacific (IP) calibrated against sea surface temperature (SST). In the fossil data, we found an analogous relationship with SST in z-corals from the WA, i.e. density increases and extension rate decreases with increasing SST, but over a significantly larger temperature window during the Plio-Pleistocene. With regard to the

  16. Metanephric adenoma with diffuse calcifications: A case report

    PubMed Central

    WU, JINGTAO; ZHU, QINGQIANG; ZHU, WENRONG; ZHANG, HONGYING

    2015-01-01

    Metanephric adenoma is a rare and benign renal neoplasm originating in the epithelial cells of the kidney. The tumor has a benign course and a characteristic histopathological appearance, typically exhibiting a solid and poorly-demarcated margin with rare cystic components or calcifications. However, it is often difficult to distinguish metanephric adenoma from malignant neoplasms prior to surgical resection. To the best of our knowledge, only one case of metastasis to the lymph nodes has been described in the literature thus far. The present study retrospectively analyzed one case of surgically and pathologically-confirmed atypical metanephric adenoma. Clinical and pathological analysis, as well as computed tomography scans, revealed a mass with a clearly defined margin and diffuse calcifications. The mass was subsequently resected and the patient recovered well following the procedure. PMID:26622757

  17. Influence of Matrix Polarity on the Properties of Ethylene Vinyl Acetate-Carbon Nanofiller Nanocomposites.

    PubMed

    George, Jinu Jacob; Bhowmick, Anil K

    2009-01-01

    A series of ethylene vinyl acetate (EVA) nanocomposites using four kinds of EVA with 40, 50, 60, and 70 wt% vinyl acetate (VA) contents and three different carbon-based nanofillers-expanded graphite (EG), multi-walled carbon nanotube (MWCNT), and carbon nanofiber (CNF) have been prepared via solution blending. The influence of the matrix polarity and the nature of nanofillers on the morphology and properties of EVA nanocomposites have been investigated. It is observed that the sample with lowest vinyl acetate content exhibits highest mechanical properties. However, the enhancement in mechanical properties with the incorporation of various nanofillers is the highest for EVA with high VA content. This trend has been followed in both dynamic mechanical properties and thermal conductivity of the nanocomposites. EVA copolymer undergoes a transition from partial to complete amorphousness between 40 and 50 wt% VA content, and this changes the dispersion of the nanofillers. The high VA-containing polymers show more affinity toward fillers due to the large free volume available and allow easy dispersion of nanofillers in the amorphous rubbery phase, as confirmed from the morphological studies. The thermal stability of the nanocomposites is also influenced by the type of nanofiller. PMID:20596353

  18. Rheological properties of wheat starch influenced by amylose-lysophosphatidylcholine complexation at different gelation phases.

    PubMed

    Ahmadi-Abhari, S; Woortman, A J J; Hamer, R J; Loos, K

    2015-05-20

    Amylose is able to form helical inclusion complexes with lysophosphatidylcholine (LPC). This complexation influences the functional and rheological properties of wheat starch; however it is well known that the formation of these complexes lead the starchy systems to a slower enzymatic hydrolysis. Based on this, to benefit from both the structuring properties of starch and also lower digestibility of the inclusion complexes, the objective of this study is the formation of amylose-LPC inclusion complexes while developing a firm network providing the desired functional properties in a starchy system. To investigate the influence of amylose-LPC complex formation at different stages of starch gelation on the viscosity behavior of wheat starch, 3% (w/w) LPC was added at three different points of the viscosity profile, obtained by rapid visco analyzer (RVA). LPC addition at all points affected the gelation behavior of wheat starch as compared with the reference. LPC addition at half-peak and peak of the viscosity profile resulted in a viscosity increase during cooling. Measuring the dynamic rheological properties of the freshly prepared gelatinized samples showed a decrease of storage modulus (G') and loss modulus (G") in the presence of LPC. During storage, in the presence of LPC, a lower elasticity was observed which indicates a lower rate of amylose retrogradation due to complexation with LPC.

  19. Influence of calcium compounds on the mechanical properties of fly ash geopolymer pastes.

    PubMed

    Temuujin, J; van Riessen, A; Williams, R

    2009-08-15

    The influence of calcium compounds (CaO and Ca(OH)(2)) on the mechanical properties of fly ash based geopolymers has been studied. Calcium compounds were substituted in fly ash at 1, 2 and 3 wt%, respectively. Curing of the geopolymers was performed at ambient temperature (20 degrees C) and 70 degrees C. Addition of calcium compounds as a fly ash substitute improved mechanical properties for the ambient temperature cured samples while decreasing properties for the 70 degrees C cured samples. Seven days compressive strength of the ambient temperature cured samples increased from 11.8 (2.9) to 22.8 (3.8)MPa and 29.2 (1.1)MPa for 3% CaO and 3% Ca(OH)(2) additions, respectively.

  20. Leveraging the withered tail tip phenotype in C. elegans to identify proteins that influence membrane properties

    PubMed Central

    Svensk, Emma; Biermann, Jana; Hammarsten, Sofia; Magnusson, Fredrik; Pilon, Marc

    2016-01-01

    ABSTRACT The properties of cellular membranes are critical for most cellular functions and are influenced by several parameters including phospholipid composition, integral and peripheral membrane proteins, and environmental conditions such as temperature. We previously showed that the C. elegans paqr-2 and iglr-2 mutants have a defect in membrane homeostasis and exhibit several distinct phenotypes, including a characteristic tail tip defect and cold intolerance. In the present study we report that screening for novel mutants with these 2 defects can lead to the identification of genes that are important contributors to membrane properties. In particular we isolated 3 novel alleles of sma-1, the C. elegans homolog of βH spectrin, and 2 novel alleles of dpy-23, which encodes the C. elegans homolog of the AP2 μ subunit. We also show that sma-1 and dpy-23 act on membrane properties in pathways distinct from that of paqr-2 and iglr-2. PMID:27695656

  1. Influence of molybdenum on the creep properties of nickel-base superalloy single crystals

    NASA Technical Reports Server (NTRS)

    Mackay, R. A.; Nathal, M. V.; Pearson, D. D.

    1990-01-01

    The Mo content of an alloy series based on Ni-6 wt pct Al-6 wt pct Ta was systematically varied from 9.8 to 14.6 wt pct, in order to ascertain the influence of Mo on the creep properties of single crystals. The optimum initial gamma-gamma prime microstructure for raft development and creep strength was established in each alloy before testing. It was found that, as the Mo content increased from 9.8 to 14.0 percent, the magnitude of the lattice mismatch increased; upon reaching 14.6 percent, a degradation of mechanical properties occurred due to the precipitation of a third phase. These results suggest that small refractory metal content and initial gamma-prime variations can profoundly affect mechanical properties.

  2. The influence of tilt grain boundaries on the mechanical properties of bicrystalline graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Xu, Na; Guo, Jian-Gang; Cui, Zhen

    2016-10-01

    The mechanical properties of bicrystalline graphene nanoribbons with various tilt grain boundaries (GBs) which typically consist of repeating pentagon-heptagon ring defects are investigated based on the method of molecular structural mechanics. The GB models are constructed via the theory of disclinations in crystals, and the elastic properties and ultimate strength of bicrystalline graphene nanoribbons are calculated under uniaxial tensile loads in perpendicular and parallel directions to grain boundaries. The dependence of mechanical properties is analyzed on the chirality and misorientation angles of graphene nanoribbons, and the experimental phenomena that Young's modulus and ultimate strength of bicrystalline graphene nanoribbons can either increase or decrease with the grain boundary angles are further verified and discussed. In addition, the influence of GB on the size effects of graphene Young's modulus is also analyzed.

  3. Calcific Tendinitis of the Gluteus Maximus in a Golfer.

    PubMed

    Williams, Ariel A; Stang, Thomas S; Fritz, Jan; Papp, Derek F

    2016-09-01

    Calcific tendinitis is a relatively rare condition in which calcium is inappropriately deposited in tendons, resulting in a local inflammatory reaction that can cause severe symptoms in certain cases. The cause of this disease process is not completely understood, although repetitive microtrauma likely plays a role in its development. Although the disorder most often involves the rotator cuff, it can affect other structures throughout the body, such as the tendons about the ankle and hip-including the rectus femoris and gluteus maximus. Nonoperative management typically involves using an anti-inflammatory medication and activity modification and can be augmented with formal physical therapy and modalities. Although nonoperative management provides adequate relief for many patients, sometimes operative debridement of the calcific deposit with or without repair of the involved tendon is required. The authors report an unusual case of calcific tendinitis of the gluteus maximus insertion in a golfer. The patient had tried nonoperative treatment for approximately 2 years with no real relief, and a recent exacerbation of the pain was significantly delaying his return to sport. Although plain radiographs did not show abnormalities, magnetic resonance imaging showed a calcific deposit in the insertion of the gluteus maximus tendon. After discussing further treatment options with the patient, the decision was made to remove the deposit and repair the insertion. He recovered completely and was able to return to play. The frequency, pathogenesis, and treatment of this condition are discussed in this case report, as well as the possible link to golf in this patient. [Orthopedics.2016; 39(5):e997-e1000.]. PMID:27337668

  4. Stone formation and calcification by nanobacteria in the human body

    NASA Astrophysics Data System (ADS)

    Ciftcioglu, Neva; Bjorklund, Michael; Kajander, E. Olavi

    1998-07-01

    The formation of discrete and organized inorganic crystalline structures within macromolecular extracellular matrices is a widespread biological phenomenon generally referred to as biomineralization. Recently, bacteria have been implicated as factors in biogeochemical cycles for formation of many minerals in aqueous sediments. We have found nanobacterial culture systems that allow for reproducible production of apatite calcification in vitro. Depending on the culture conditions, tiny nanocolloid-sized particles covered with apatite, forming various size of aggregates and stones were observed. In this study, we detected the presence of nanobacteria in demineralized trilobit fossil, geode, apatite, and calcite stones by immunofluorescence staining. Amethyst and other quartz stones, and chalk gave negative results. Microorganisms are capable of depositing apatite outside the thermodynamic equilibrium in sea water. We bring now evidence that this occurs in the human body as well. Previously, only struvite kidney stones composed of magnesium ammonium phosphate and small amounts of apatite have been regarded as bacteria related. 90 percent of demineralized human kidney stones now screened, contained nanobacteria. At least three different distribution patterns of nanobacteria were conditions, and human kidney stones that are formed from small apatite units. Prerequisites for the formation of kidney stones are the supersaturation of urine and presence of nidi for crystallization. Nanobacteria are important nidi and their presence might be of special interest in space flights where supersaturation of urine is present due to the loss of bone. Furthermore, we bring evidence that nanobacteria may act as crystallization nidi for the formation of biogenic apatite structures in tissue calcification found in e.g., atherosclerotic plaques, extensive metastatic and tumoral calcification, acute periarthritis, malacoplakia, and malignant diseases. In nanaobacteria-infected fibroblasts

  5. Modelling coral polyp calcification in relation to ocean acidification

    NASA Astrophysics Data System (ADS)

    Hohn, S.; Merico, A.

    2012-11-01

    Rising atmospheric CO2 concentrations due to anthropogenic emissions induce changes in the carbonate chemistry of the oceans and, ultimately, a drop in ocean pH. This acidification process can harm calcifying organisms like coccolithophores, molluscs, echinoderms, and corals. It is expected that ocean acidification in combination with other anthropogenic stressors will cause a severe decline in coral abundance by the end of this century, with associated disastrous effects on reef ecosystems. Despite the growing importance of the topic, little progress has been made with respect to modelling the impact of acidification on coral calcification. Here we present a model for a coral polyp that simulates the carbonate system in four different compartments: the seawater, the polyp tissue, the coelenteron, and the calcifying fluid. Precipitation of calcium carbonate takes place in the metabolically controlled calcifying fluid beneath the polyp tissue. The model is adjusted to a state of activity as observed by direct microsensor measurements in the calcifying fluid. We find that a transport mechanism for bicarbonate is required to supplement carbon into the calcifying fluid because CO2 diffusion alone is not sufficient to sustain the observed calcification rates. Simulated CO2 perturbation experiments reveal decreasing calcification rates under elevated pCO2 despite the strong metabolic control of the calcifying fluid. Diffusion of CO2 through the tissue into the calcifying fluid increases with increasing seawater pCO2, leading to decreased aragonite saturation in the calcifying fluid. Our modelling study provides important insights into the complexity of the calcification process at the organism level and helps to quantify the effect of ocean acidification on corals.

  6. Continuous melt granulation: Influence of process and formulation parameters upon granule and tablet properties.

    PubMed

    Monteyne, Tinne; Vancoillie, Jochem; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-10-01

    The pharmaceutical industry has a growing interest in alternative manufacturing models allowing automation and continuous production in order to improve process efficiency and reduce costs. Implementing a switch from batch to continuous processing requires fundamental process understanding and the implementation of quality-by-design (QbD) principles. The aim of this study was to examine the relationship between formulation-parameters (type binder, binder concentration, drug-binder miscibility), process-parameters (screw speed, powder feed rate and granulation temperature), granule properties (size, size distribution, shape, friability, true density, flowability) and tablet properties (tensile strength, friability, dissolution rate) of four different drug-binder formulations using Design of experiments (DOE). Two binders (polyethylene glycol (PEG) and Soluplus®) with a different solid state, semi-crystalline vs amorphous respectively, were combined with two model-drugs, metoprolol tartrate (MPT) and caffeine anhydrous (CAF), both having a contrasting miscibility with the binders. This research revealed that the granule properties of miscible drug-binder systems depended on the powder feed rate and barrel filling degree of the granulator whereas the granule properties of immiscible systems were mainly influenced by binder concentration. Using an amorphous binder, the tablet tensile strength depended on the granule size. In contrast, granule friability was more important for tablet quality using a brittle binder. However, this was not the case for caffeine-containing blends, since these phenomena were dominated by the enhanced compression properties of caffeine Form I, which was formed during granulation. Hence, it is important to gain knowledge about formulation behavior during processing since this influences the effect of process parameters onto the granule and tablet properties. PMID:27449628

  7. Continuous melt granulation: Influence of process and formulation parameters upon granule and tablet properties.

    PubMed

    Monteyne, Tinne; Vancoillie, Jochem; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2016-10-01

    The pharmaceutical industry has a growing interest in alternative manufacturing models allowing automation and continuous production in order to improve process efficiency and reduce costs. Implementing a switch from batch to continuous processing requires fundamental process understanding and the implementation of quality-by-design (QbD) principles. The aim of this study was to examine the relationship between formulation-parameters (type binder, binder concentration, drug-binder miscibility), process-parameters (screw speed, powder feed rate and granulation temperature), granule properties (size, size distribution, shape, friability, true density, flowability) and tablet properties (tensile strength, friability, dissolution rate) of four different drug-binder formulations using Design of experiments (DOE). Two binders (polyethylene glycol (PEG) and Soluplus®) with a different solid state, semi-crystalline vs amorphous respectively, were combined with two model-drugs, metoprolol tartrate (MPT) and caffeine anhydrous (CAF), both having a contrasting miscibility with the binders. This research revealed that the granule properties of miscible drug-binder systems depended on the powder feed rate and barrel filling degree of the granulator whereas the granule properties of immiscible systems were mainly influenced by binder concentration. Using an amorphous binder, the tablet tensile strength depended on the granule size. In contrast, granule friability was more important for tablet quality using a brittle binder. However, this was not the case for caffeine-containing blends, since these phenomena were dominated by the enhanced compression properties of caffeine Form I, which was formed during granulation. Hence, it is important to gain knowledge about formulation behavior during processing since this influences the effect of process parameters onto the granule and tablet properties.

  8. ARTHROSCOPY FOR TREATMENT OF REFRACTORY CALCIFIC TENDONITIS OF THE SHOULDER

    PubMed Central

    Fernandes, Marcos Rassi; Fernandes, Rui José

    2015-01-01

    Objective: To evaluate the results from arthroscopic treatment in patients with calcific tendonitis of the shoulder. Methods: Between September 2001 and June 2006, 55 patients with calcific tendonitis of the shoulder that was resistant to conservative treatment were evaluated, with follow-up of 12 to 70 months. The mean age was 42 years, ranging from 30 to 64 years; 44 patients were female (80%). There were 37 right shoulders, and 63.63% of the cases were on the dominant side. Pain was the main symptom, and the mean time between onset of symptoms and arthroscopy was 38 months (range: five to 120 months). The tendon affected was the supraspinatus in 42 cases, the infraspinatus in 11 cases and an association between these in two cases. Acromioplasty was carried out in 12 patients (21.82%) and subacromial bursectomy was performed in all cases. Results: According to the UCLA criteria, 46 cases were excellent and six were good, making a total of 52 satisfactory results (94.54%). Conclusion: Arthroscopic treatment of calcific tendonitis of the shoulder appears to be an effective method, with high rates of satisfactory results. Associated acromioplasty is not necessary. PMID:27019839

  9. Peripheral arterial calcification: Prevalence, mechanism, detection, and clinical implications

    PubMed Central

    Rocha-Singh, Krishna J; Zeller, Thomas; Jaff, Michael R

    2014-01-01

    Vascular calcification (VC), particularly medial (Mönckeberg's medial sclerosis) arterial calcification, is common in patients with diabetes mellitus and chronic kidney disease and is associated with increased cardiovascular morbidity and mortality. Although, the underlying pathophysiological mechanisms and genetic pathways of VC are not fully known, hypocalcemia, hyperphosphatemia, and the suppression of parathyroid hormone activity are central to the development of vessel mineralization and, consequently, bone demineralization. In addition to preventive measures, such as the modification of atherosclerotic cardiovascular risk factors, current treatment strategies include the use of calcium-free phosphate binders, vitamin D analogs, and calcium mimetics that have shown promising results, albeit in small patient cohorts. The impact of intimal and medial VC on the safety and effectiveness of endovascular devices to treat symptomatic peripheral arterial disease (PAD) remains poorly defined. The absence of a generally accepted, validated vascular calcium grading scale hampers clinical progress in assessing the safety and utility of various endovascular devices (e.g., atherectomy) in treating calcified vessels. Accordingly, we propose the peripheral arterial calcium scoring system (PACSS) and a method for its clinical validation. A better understanding of the pathogenesis of vascular calcification and the development of optimal medical and endovascular treatment strategies are crucial as the population ages and presents with more chronic comorbidities. PMID:24402839

  10. Osteoprotegerin and Vascular Calcification: Clinical and Prognostic Relevance.

    PubMed

    Makarović, Sandra; Makarović, Zorin; Steiner, Robert; Mihaljević, Ivan; Milas-Ahić, Jasminka

    2015-06-01

    Osteoprotegerin (OPG) is a key regulator in bone metabolism, that also has effect in vascular system. Studies suggest that osteoprotegerin is a critical arterial calcification inhibitor, and is released by endothelial cells as a protective mechanism for their survival in certain pathological conditions, such as diabetes mellitus, chronic kidney disease, and other metabolic disorders. That has been shown in studies in vitro and in animal models. The discovery that OPG deficient mice (OPG -/- mice) develop severe osteoporosis and arterial calcification, has led to conclusion that osteoprotegerin might be mulecule linking vascular and bone system. Paradoxically however, clinical trials have shown recently that OPG serum levels is increased in coronary artery disease and correlates with its severity, ischemic cardial decompensation, and future cardiovascular events. Therefore it is possible that osteoprotegerin could have a new function as a potential biomarker in early identification and monitoring patients with cardiovascular disease. Amongst that osteoprotegerin is in association with well known atherosclerosis risc factors: undoubtedly it is proven its relationship with age, smoking and diabetes mellitus. There is evidence regarding presence of hyperlipoproteinemia and increased serum levels of osteoprotegerin. Also the researches have been directed in genetic level, linking certain single nucleotid genetic polymorphisms of osteoprotegerin and vascular calcification appearance. This review emphasises multifactorial role of OPG, presenting numerous clinical and experimental studies regarding its role in vascular pathology, suggesting a novel biomarker in cardiovascular diseases, showing latest conclusions about this interesting topic that needs to be further explored. PMID:26753467

  11. In vitro models of aortic valve calcification: solidifying a system.

    PubMed

    Bowler, Meghan A; Merryman, W David

    2015-01-01

    Calcific aortic valve disease (CAVD) affects 25% of people over 65, and the late-stage stenotic state can only be treated with total valve replacement, requiring 85,000 surgeries annually in the US alone (University of Maryland Medical Center, 2013, http://umm.edu/programs/services/heart-center-programs/cardiothoracic-surgery/valve-surgery/facts). As CAVD is an age-related disease, many of the affected patients are unable to undergo the open-chest surgery that is its only current cure. This challenge motivates the elucidation of the mechanisms involved in calcification, with the eventual goal of alternative preventative and therapeutic strategies. There is no sufficient animal model of CAVD, so we turn to potential in vitro models. In general, in vitro models have the advantages of shortened experiment time and better control over multiple variables compared to in vivo models. As with all models, the hypothesis being tested dictates the most important characteristics of the in vivo physiology to recapitulate. Here, we collate the relevant pieces of designing and evaluating aortic valve calcification so that investigators can more effectively draw significant conclusions from their results. PMID:25249188

  12. In vitro Models of Aortic Valve Calcification: Solidifying a System

    PubMed Central

    Bowler, Meghan A.; Merryman, W. David

    2014-01-01

    Calcific aortic valve disease (CAVD) affects 25% of people over 65, and the late-stage stenotic state can only be treated with total valve replacement, requiring 85,000 surgeries annually in the US alone [1]. As CAVD is an age-related disease, many of the affected patients are unable to undergo the open-chest surgery that is its only current cure. This challenge motivates the elucidation of the mechanisms involved in calcification, with the eventual goal of alternative preventative and therapeutic strategies. There is no sufficient animal model of CAVD, so we turn to potential in vitro models. In general, in vitro models have the advantages of shortened experiment time and better control over multiple variables compared to in vivo models. As with all models, the hypothesis being tested dictates the most important characteristics of the in vivo physiology to recapitulate. Here, we collate the relevant pieces of designing and evaluating aortic valve calcification so that investigators can more effectively draw significant conclusions from their results. PMID:25249188

  13. Hydrologic influences on soil properties along ephemeral rivers in the Namib Desert

    USGS Publications Warehouse

    Jacobson, P.J.; Jacobson, K.M.; Angermeier, P.L.; Cherry, D.S.

    2000-01-01

    Soils were examined along three ephemeral rivers in the Namib Desert to assess the influence of their hydrologic characteristics on soil properties. Soils consisted of layers of fluvially deposited, organic-rich silts, interstratified with fluvial and aeolian sands. The most significant influence of the ephemeral hydrologic regime upon soils was related to the downstream alluviation associated with hydrologic decay. This alluviation increased the silt proportion of soils in the lower reaches of the rivers. Organic carbon, nitrogen and phosphorous were correlated with silt content, and silt deposition patterns influenced patterns of moisture availability and plant rooting, creating and maintaining micro-habitats for various organisms. Localized salinization occurred in association with wetland sites and soluble salt content tended to increase downstream. Because of the covariance between silt and macronutrients, and the influence of silt upon moisture availability and habitat suitability, alluviation patterns associated with the hydrologic regime strongly influence the structure, productivity, and spatial distribution of biotic communities in ephemeral river ecosystems. (C) 2000 Academic Press.

  14. The role of cellular senescence during vascular calcification: a key paradigm in aging research.

    PubMed

    Mackenzie, N C W; MacRae, V E

    2011-07-01

    Vascular calcification has severe clinical consequences and is considered an accurate predictor of future adverse cardiovascular events. Vascular calcification refers to the deposition of calcium phosphate mineral, most often hydroxyapatite, in arteries. Extensive calcification of the vascular system is a key characteristic of aging. In this article, we outline the mechanisms governing vascular calcification and highlight its association with cellular senescence. This review discusses the molecular mechanisms of cellular senescence and its affect on calcification of vascular cells, the relevance of phosphate regulation and the function of FGF23 and Klotho proteins. The association of vascular calcification and cellular senescence with the rare human aging disorder Hutchison-Gilford Progeria Syndrome (HGPS) is highlighted and the mouse models used to try to determine the underlying pathways are discussed. By understanding the pathways involved in these processes novel drug targets may be elucidated in an effort to reduce the effects of cellular aging as a risk factor in cardiovascular disease.

  15. Effect of image quality on calcification detection in digital mammography

    PubMed Central

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-01-01

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  16. Effect of image quality on calcification detection in digital mammography

    SciTech Connect

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-06-15

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  17. Tracking calcification in tissue-engineered bone using synchrotron micro-FTIR and SEM.

    PubMed

    Deegan, Anthony J; Cinque, Gianfelice; Wehbe, Katia; Konduru, Sandeep; Yang, Ying

    2015-02-01

    One novel tissue engineering approach to mimic in vivo bone formation is the use of aggregate or micromass cultures. Various qualitative and quantitative techniques, such as histochemical staining, protein assay kits and RT-PCR, have been used previously on cellular aggregate studies to investigate how these intricate arrangements lead to mature bone tissue. However, these techniques struggle to reveal spatial and temporal distribution of proliferation and mineralization simultaneously. Synchrotron-based Fourier transform infrared microspectroscopy (micro-FTIR) offers a unique insight at the molecular scale by coupling high IR sensitivity to organic matter with the high spatial resolution allowed by diffraction limited SR microbeam. This study is set to investigate the effects of culture duration and aggregate size on the dynamics and spatial distribution of calcification in engineered bone aggregates by a combination of micro-FTIR and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX). A murine bone cell line has been used, and small/large bone aggregates have been induced using different chemically treated culture substrates. Our findings suggest that bone cell aggregate culturing can greatly increase levels of mineralization over short culture periods. The size of the aggregates influences mineralisation rates with larger aggregates mineralizing at a faster rate than their smaller counterparts. The micro-FTIR mapping has demonstrated that mineralization in the larger aggregates initiated from the periphery and spread to the centre, whilst the smaller aggregates have more minerals in the centre at the early stage and deposited more in the periphery after further culturing, implying that aggregate size influences calcification distribution and development over time. SEM/EDX data correlates well with the micro-FTIR results for the total mineral content. Thus, synchrotron-based micro-FTIR can accurately track mineralization process

  18. Tracking calcification in tissue-engineered bone using synchrotron micro-FTIR and SEM.

    PubMed

    Deegan, Anthony J; Cinque, Gianfelice; Wehbe, Katia; Konduru, Sandeep; Yang, Ying

    2015-02-01

    One novel tissue engineering approach to mimic in vivo bone formation is the use of aggregate or micromass cultures. Various qualitative and quantitative techniques, such as histochemical staining, protein assay kits and RT-PCR, have been used previously on cellular aggregate studies to investigate how these intricate arrangements lead to mature bone tissue. However, these techniques struggle to reveal spatial and temporal distribution of proliferation and mineralization simultaneously. Synchrotron-based Fourier transform infrared microspectroscopy (micro-FTIR) offers a unique insight at the molecular scale by coupling high IR sensitivity to organic matter with the high spatial resolution allowed by diffraction limited SR microbeam. This study is set to investigate the effects of culture duration and aggregate size on the dynamics and spatial distribution of calcification in engineered bone aggregates by a combination of micro-FTIR and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX). A murine bone cell line has been used, and small/large bone aggregates have been induced using different chemically treated culture substrates. Our findings suggest that bone cell aggregate culturing can greatly increase levels of mineralization over short culture periods. The size of the aggregates influences mineralisation rates with larger aggregates mineralizing at a faster rate than their smaller counterparts. The micro-FTIR mapping has demonstrated that mineralization in the larger aggregates initiated from the periphery and spread to the centre, whilst the smaller aggregates have more minerals in the centre at the early stage and deposited more in the periphery after further culturing, implying that aggregate size influences calcification distribution and development over time. SEM/EDX data correlates well with the micro-FTIR results for the total mineral content. Thus, synchrotron-based micro-FTIR can accurately track mineralization process

  19. Influence of Halide Solutions on Collagen Networks: Measurements of Physical Properties by Atomic Force Microscopy

    PubMed Central

    Kempe, André; Lackner, Maximilian

    2016-01-01

    The influence of aqueous halide solutions on collagen coatings was tested. The effects on resistance against indentation/penetration on adhesion forces were measured by atomic force microscopy (AFM) and the change of Young's modulus of the coating was derived. Comparative measurements over time were conducted with halide solutions of various concentrations. Physical properties of the mesh-like coating generally showed large variability. Starting with a compact set of physical properties, data disperse after minutes. A trend of increase in elasticity and permeability was found for all halide solutions. These changes were largest in NaI, displaying a logical trend with ion size. However a correlation with concentration was not measured. Adhesion properties were found to be independent of mechanical properties. The paper also presents practical experience for AFM measurements of soft tissue under liquids, particularly related to data evaluation. The weakening in physical strength found after exposure to halide solutions may be interpreted as widening of the network structure or change in the chemical properties in part of the collagen fibres (swelling). In order to design customized surface coatings at optimized conditions also for medical applications, halide solutions might be used as agents with little impact on the safety of patients. PMID:27721994

  20. The influence of large deformations on mechanical properties of sinusoidal ligament structures

    NASA Astrophysics Data System (ADS)

    Strek, Tomasz; Jopek, Hubert; Wojciechowski, Krzysztof W.

    2016-05-01

    Studies of mechanical properties of materials, both theoretical and experimental, usually deal with linear characteristics assuming a small range of deformations. In particular, not much research has been published devoted to large deformations of auxetic structures - i.e. structures exhibiting negative Poisson’s ratio. This paper is focused on mechanical properties of selected structures that are subject to large deformations. Four examples of structure built of sinusoidal ligaments are studied and for each geometry the impact of deformation size and geometrical parameters on the effective mechanical properties of these structures are investigated. It is shown that some of them are auxetic when compressed and non-auxetic when stretched. Geometrical parameters describing sinusoidal shape of ligaments strongly affect effective mechanical properties of the structure. In some cases of deformation, the increase of the value of amplitude of the sinusoidal shape decreases the effective Poisson’s ratio by 0.7. Therefore the influence of geometry, as well as the arrangement of ligaments allows for smart control of mechanical properties of the sinusoidal ligament structure being considered. Given the large deformation of the structure, both a linear elastic material model, and a hyperelastic Neo-Hookean material model are used.

  1. Influence of Thermal and Radiation Effects on Microstructural and Mechanical Properties of Nb-1Zr

    SciTech Connect

    Leonard, Keith J; Busby, Jeremy T; Zinkle, Steven J

    2011-01-01

    Refractory metals and alloys offer attractive high-temperature properties, most of which are suitable for applications in nuclear environments including high temperature strength, good thermal conductivity, and compatibility with most liquid metal coolants. One of only two commercially produced Nb-alloys, Nb-1Zr has long been considered for various compact reactor designs. Nb-1Zr has also recently been considered for high-performance Gen IV gas reactor concepts. However, there are significant gaps in the irradiated materials database, especially at temperatures above 800 K. Recent work has shown that irradiated properties of Nb-1Zr are strongly controlled by phase-related transformations in the microstructure. Changes in the microstructure (obtained via scanning and transmission electron microscopy) and corresponding mechanical properties of Nb-1Zr were examined following fission reactor irradiation experiments at temperatures of 1073, 1223 and 1373 K to 1.9 dpa (displacements per atom) and compared with material thermally aged for similar exposure times of ~1100 h. Thermally driven changes in the development of precipitate phases showed a greater influence on mechanical properties compared to irradiation-induced defects for these irradiation conditions. The changes in material density, electrical resistivity and mechanical properties of the irradiated and thermally aged materials in association with microstructural developments are discussed.

  2. Metal matrix composite micromechanics: In-situ behavior influence on composite properties

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Hopkins, D. A.; Chamis, C. C.

    1989-01-01

    Recent efforts in computational mechanics methods for simulating the nonlinear behavior of metal matrix composites have culminated in the implementation of the Metal Matrix Composite Analyzer (METCAN) computer code. In METCAN material nonlinearity is treated at the constituent (fiber, matrix, and interphase) level where the current material model describes a time-temperature-stress dependency of the constituent properties in a material behavior space. The composite properties are synthesized from the constituent instantaneous properties by virtue of composite micromechanics and macromechanics models. The behavior of metal matrix composites depends on fabrication process variables, in situ fiber and matrix properties, bonding between the fiber and matrix, and/or the properties of an interphase between the fiber and matrix. Specifically, the influence of in situ matrix strength and the interphase degradation on the unidirectional composite stress-strain behavior is examined. These types of studies provide insight into micromechanical behavior that may be helpful in resolving discrepancies between experimentally observed composite behavior and predicted response.

  3. The influence of soil hydraulic properties on bare soil evaporation dynamics

    NASA Astrophysics Data System (ADS)

    Durner, Wolfgang; Iden, Sascha C.; Diamantopoulos, Efstathios

    2015-04-01

    Evaporation from bare soil is an important component of the global water cycle and the energy balance of the earth's surface. Forecasting bare soil evaporation requires knowledge of physical soil properties like thermal and hydraulic conductivity, heat and water capacity, and the water-content dependency of the albedo. The focus of this contribution is to analyze the sensitivity of soil evaporation dynamics with respect to physical soil properties. A coupled numerical model of water, vapor, and heat flow in soil considering the surface energy balance and temperature effects on the transport coefficients is used for the analysis. Particular attention is devoted to the influence of soil hydraulic properties on the duration of stage-one evaporation and evaporation rates during stage-two. We illustrate the importance of an adequate parameterization of soil hydraulic properties which should account for water sorption in dry soil, water flow in completely and incompletely-filled pores, and vapor diffusion. A comparison with data from evaporation experiments in the laboratory under different atmospheric forcings provides the link between models and reality. This confrontation unveils that the use of classic parametrizations of soil hydraulic properties leads to a bias in the description of experimental data and model predictions.

  4. Elucidating the Molecular-Level Events in Valvular Interstitial Cell Calcification to Improve the Design of Tissue-Engineered Heart Valves

    NASA Astrophysics Data System (ADS)

    Gu, Xiaoxiao

    Calcification is the leading cause of native and bioprosthetic heart valve failure, yet its etiology and progression remain poorly understood. Total valve replacement, which is both invasive and accompanied by numerous shortcomings, is commonly performed to replace stenotic valves, but there are currently no medical agents that are FDA-approved for the prevention of aortic valve disease progression. Tissue engineering offers an attractive alternative to current valve replacement options. Thus, there is a pressing need to: (1) better understand the progression of valve calcification, (2) develop more options for prevention and treatment of valve calcification, and (3) define the properties of appropriate scaffold environments that will support the growth of engineered valve tissue. In this thesis, we describe our plan to bring together these goals in cardiovascular medicine: we aim to identify differences between calcifying and non-calcifying valve cultures and then use this information to discover potential calcification inhibitors and define biomaterial environments that can be used to support either healthy or diseased valvular interstitial cell function.

  5. Using 137 Cs measurements to investigate the influence of erosion and soil redistribution on soil properties.

    PubMed

    Du, P; Walling, D E

    2011-05-01

    Information on the interaction between soil erosion and soil properties is an important requirement for sustainable management of the soil resource. The relationship between soil properties and the soil redistribution rate, reflecting both erosion and deposition, is an important indicator of this interaction. This relationship is difficult to investigate using traditional approaches to documenting soil redistribution rates involving erosion plots and predictive models. However, the use of the fallout radionuclide (137)Cs to document medium-term soil redistribution rates offers a means of overcoming many of the limitations associated with traditional approaches. The study reported sought to demonstrate the potential for using (137)Cs measurements to assess the influence of soil erosion and redistribution on soil properties (particle size composition, total C, macronutrients N, P, K and Mg, micronutrients Mn, Mo, Fe, Cu and Zn and other elements, including Ti and As). (137)Cs measurements undertaken on 52 soil cores collected within a 7 ha cultivated field located near Colebrooke in Devon, UK were used to establish the magnitude and spatial pattern of medium-term soil redistribution rates within the field. The soil redistribution rates documented for the individual sampling points within the field ranged from an erosion rate of -12.9 t ha(-1) yr(-1) to a deposition rate of 19.2 t ha(-1) yr(-1). Composite samples of surface soil (0-5 cm) were collected immediately adjacent to each coring point and these samples were analysed for a range of soil properties. Individual soil properties associated with these samples showed significant variability, with CV values generally lying in the range 10-30%. The relationships between the surface soil properties and the soil redistribution rate were analysed. This analysis demonstrated statistically significant relationships between some soil properties (total phosphorus, % clay, Ti and As) and the soil redistribution rate, but for

  6. Influence of color on dielectric properties of marinated poultry breast meat.

    PubMed

    Samuel, D; Trabelsi, S

    2012-08-01

    The dielectric behavior of foods when exposed to radio-frequency and microwave electric fields is highly influenced by moisture content and the degree of water binding with constituents of the food materials. The ability to correlate specific food quality characteristics with the dielectric properties can lead to the development of rapid, nondestructive techniques for such quality measurements. Water-holding capacity is a critical attribute in meat quality. Up to 50% of raw poultry meat in the United States is marinated with mixtures of water, salts, and phosphates. The objective of this study was to determine if variations in breast meat color would affect the dielectric properties of marinated poultry meat over a broad frequency range from 500 MHz to 50 GHz. Poultry meat was obtained from a local commercial plant in Georgia (USA). Color and pH measurements were taken on the breast filets. Groups of breast filets were sorted into classes of pale and normal before adding marination pickup percentages of 0, 5, 10, and 15. Breast filets were vacuum-tumbled and weighed for pickup percentages. Dielectric properties of the filets were measured with a coaxial open-ended probe on samples equilibrated to 25°C. Samples from pale meat exhibited higher dielectric properties than samples from normal meat. No differences could be observed between samples from pale and normal meat after marination of the samples. Overall, dielectric properties increased as the marination pickup increased (α=0.05). Marination pickup strongly influenced the dielectric loss factor. Differences between samples marinated at different pickup levels were more pronounced at lower frequencies for the dielectric loss factor. As frequency increased, the differences between samples decreased. Differences in dielectric constant between samples were not as consistent as those seen with the dielectric loss factor.

  7. Influence of processing sequence on the tribological properties of VGCF-X/PA6/SEBS composites

    NASA Astrophysics Data System (ADS)

    Osada, Yu; Nishitani, Yosuke; Kitano, Takeshi

    2016-03-01

    In order to develop the new tribomaterials for mechanical sliding parts with sufficient balance of mechanical and tribological properties, we investigated the influence of processing sequence on the tribological properties of the ternary nanocomposites: the polymer blends of polyamide 6 (PA6) and styrene-ethylene/butylene-styrene copolymer (SEBS) filled with vapor grown carbon fiber (VGCF-X), which is one of carbon nanofiber (CNF) and has 15nm diameter and 3μm length. Five different processing sequences: (1) VGCF-X, PA6 and SEBS were mixed simultaneously (Process A), (2) Re-mixing (Second compounding) of the materials prepared by Process A (Process AR),(3) SEBS was blended with PA6 (PA6/SEBS blends) and then these blends were mixed with VGCF-X (Process B), (4) VGCF-X was mixed with PA6 (VGCF-X/PA6 composites) and then these composites were blended with SEBS (Process C), and (5) VGCF-X were mixed with SEBS (VGCF-X/SEBS composites) and then these composites were blended with PA6 (Process D) were attempted for preparing of the ternary nanocomposites (VGCF-X/PA6/SEBS composites). These ternary polymer nanocomposites were extruded by a twin screw extruder and injection-molded. Their tribological properties were evaluated by using a ring-on-plate type sliding wear tester under dry condition. The tribological properties such as the frictional coefficient and the specific wear rate were influenced by the processing sequence. These results may be attributed to the change of internal structure formation, which is a dispersibility of SEBS particle and VGCF-X in ternary nanocomposites (VGCF-X/PA6/SEBS) by different processing sequences. In particular, the processing sequences of AR, B and D, which are those of re-mixing of VGCF-X, have a good dispersibility of VGCF-X for the improvement of tribological properties.

  8. Needle-like ion-doped hydroxyapatite crystals influence osteogenic properties of PCL composite scaffolds.

    PubMed

    Guarino, V; Veronesi, F; Marrese, M; Giavaresi, G; Ronca, A; Sandri, M; Tampieri, A; Fini, M; Ambrosio, Luigi

    2016-02-01

    Surface topography and chemistry both play a crucial role on influencing cell response in 3D porous scaffolds in terms of osteogenesis. Inorganic materials with peculiar morphology and chemical functionalities may be proficiently used to improve scaffold properties-in the bulk and along pore surface-promoting in vitro and in vivo osseous tissue in-growth. The present study is aimed at investigating how bone regenerative properties of composite scaffolds made of poly(Ɛ-caprolactone) (PCL) can be augmented by the peculiar properties of Mg(2+) ion doped hydroxyapatite (dHA) crystals, mainly emphasizing the role of crystal shape on cell activities mediated by microstructural properties. At the first stage, the study of mechanical response by crossing experimental compression tests and theoretical simulation via empirical models, allow recognizing a significant contribution of dHA shape factor on scaffold elastic moduli variation as a function of the relative volume fraction. Secondly, the peculiar needle-like shape of dHA crystals also influences microscopic (i.e. crystallinity, adhesion forces) and macroscopic (i.e. roughness) properties with relevant effects on biological response of the composite scaffold: differential scanning calorimetry (DSC) analyses clearly indicate a reduction of crystallization heat-from 66.75 to 43.05 J g(-1)-while atomic force microscopy (AFM) ones show a significant increase of roughness-from (78.15  ±  32.71) to (136.13  ±  63.21) nm-and of pull-off forces-from 33.7% to 48.7%. Accordingly, experimental studies with MG-63 osteoblast-like cells show a more efficient in vitro secretion of alkaline phosphatase (ALP) and collagen I and a more copious in vivo formation of new bone trabeculae, thus suggesting a relevant role of dHA to support the main mechanisms involved in bone regeneration. PMID:26928781

  9. The influence of type 2 diabetes on fibrin clot properties in patients with coronary artery disease.

    PubMed

    Neergaard-Petersen, S; Hvas, A-M; Kristensen, S D; Grove, E L; Larsen, S B; Phoenix, F; Kurdee, Z; Grant, P J; Ajjan, R A

    2014-12-01

    Type 2 diabetes mellitus (T2DM) increases the risk of coronary thrombosis and both conditions are associated with altered fibrin clot properties. However, the influence of T2DM on fibrin clot properties in patients with coronary artery disease (CAD) remains unclear. We aimed to investigate the influence of T2DM on fibrin clot properties in patients with CAD. Fibrin clot structure and fibrinolysis were investigated in 581 CAD patients (148 with T2DM) using turbidimetric assays, confocal and scanning electron microscopy. Clots made from plasma and plasma-purified fibrinogen were studied, and plasma levels of inflammatory markers were analysed. T2DM patients had increased clot maximum absorbance compared with non-diabetic patients (0.36 ± 0.1 vs 0.33 ± 0.1 au; p=0.01), displayed longer lysis time (804 [618;1002] vs 750 [624;906] seconds; p=0.03) and showed more compact fibrin structure assessed by confocal and electron microscopy. Fibrinogen levels were elevated in T2DM (p< 0.001), but clots made from purified fibrinogen showed no differences in fibrin properties in the two populations. Adjusting for fibrinogen levels, T2DM was associated with C-reactive protein and complement C3 plasma levels, with the former correlating with clot maximum absorbance (r=0.24, p< 0.0001) and the latter with lysis time (r=0.30, p< 0.0001). Independent of fibrinogen levels, females had more compact clots with prolonged lysis time compared with males (all p-values< 0.001). In conclusion, T2DM is associated with prothrombotic changes in fibrin clot properties in patients with CAD. This is related to quantitative rather than qualitative changes in fibrinogen with a possible role for inflammatory proteins. PMID:25187394

  10. Short term preservation of hide using vacuum: influence on properties of hide and of processed leather.

    PubMed

    Gudro, Ilze; Valeika, Virgilijus; Sirvaitytė, Justa

    2014-01-01

    The objective of this work was to investigate vacuum influence on hide preservation time and how it affects hide structure. It was established that vacuum prolongs the storage time without hide tissue putrefaction up to 21 days when the storage temperature is 4°C. The microorganisms act for all storage times, but the action is weak and has no observable influence on the quality of hide during the time period mentioned. The hide shrinkage temperature decrease is negligible, which shows that breaking of intermolecular bonds does not occur. Optical microscopy, infrared spectroscopy and differential scanning calorimetry also did not show any structural changes which can influence the quality of leather produced from such hide. The qualitative indexes of wet blue processed under laboratory conditions and of leather produced during industrial trials are presented. Indexes such as chromium compounds exhaustion, content of chromium in leather, content of soluble matter in dichloromethane, strength properties, and shrinkage temperature were determined. Properties of the leather produced from vacuumed hide under industrial conditions conformed to the requirements of shoe upper leather.

  11. Short Term Preservation of Hide Using Vacuum: Influence on Properties of Hide and of Processed Leather

    PubMed Central

    Gudro, Ilze; Valeika, Virgilijus; Sirvaitytė, Justa

    2014-01-01

    The objective of this work was to investigate vacuum influence on hide preservation time and how it affects hide structure. It was established that vacuum prolongs the storage time without hide tissue putrefaction up to 21 days when the storage temperature is 4°C. The microorganisms act for all storage times, but the action is weak and has no observable influence on the quality of hide during the time period mentioned. The hide shrinkage temperature decrease is negligible, which shows that breaking of intermolecular bonds does not occur. Optical microscopy, infrared spectroscopy and differential scanning calorimetry also did not show any structural changes which can influence the quality of leather produced from such hide. The qualitative indexes of wet blue processed under laboratory conditions and of leather produced during industrial trials are presented. Indexes such as chromium compounds exhaustion, content of chromium in leather, content of soluble matter in dichloromethane, strength properties, and shrinkage temperature were determined. Properties of the leather produced from vacuumed hide under industrial conditions conformed to the requirements of shoe upper leather. PMID:25393637

  12. Does the casting mode influence microstructure, fracture and properties of different metal ceramic alloys?

    PubMed

    Bauer, José Roberto de Oliveira; Grande, Rosa Helena Miranda; Rodrigues-Filho, Leonardo Eloy; Pinto, Marcelo Mendes; Loguercio, Alessandro Dourado

    2012-01-01

    The aim of the present study was to evaluate the tensile strength, elongation, microhardness, microstructure and fracture pattern of various metal ceramic alloys cast under different casting conditions. Two Ni-Cr alloys, Co-Cr and Pd-Ag were used. The casting conditions were as follows: electromagnetic induction under argon atmosphere, vacuum, using blowtorch without atmosphere control. For each condition, 16 specimens, each measuring 25 mm long and 2.5 mm in diameter, were obtained. Ultimate tensile strength (UTS) and elongation (EL) tests were performed using a Kratos machine. Vickers Microhardness (VM), fracture mode and microstructure were analyzed by SEM. UTS, EL and VM data were statistically analyzed using ANOVA. For UTS, alloy composition had a direct influence on casting condition of alloys (Wiron 99 and Remanium CD), with higher values shown when cast with Flame/Air (p < 0.05). The factors 'alloy" and 'casting condition" influenced the EL and VM results, generally presenting opposite results, i.e., alloy with high elongation value had lower hardness (Wiron 99), and casting condition with the lowest EL values had the highest VM values (blowtorch). Both factors had significant influence on the properties evaluated, and prosthetic laboratories should select the appropriate casting method for each alloy composition to obtain the desired property. PMID:22641437

  13. Influence of internal temperature development during manufacturing on thick laminates compression fatigue properties

    NASA Astrophysics Data System (ADS)

    Lahuerta, F.; Nijssen, RPL

    2016-07-01

    Thick laminates (above 6 mm) are increasingly present in large composite structures such as wind turbine blades. Blade designs are based on static and fatigue coupon tests on 14mm thick laminates. However, a thickness effect has been observed, showing significantly shorter fatigue life in thick laminates. Different factors are suspected to be involved in the decreased static and dynamic performance of thick laminates. These include the effect of selfheating during fatigue testing, scaling effects, and the influence of residual stresses due to temperature gradients during manufacturing. This work studies the influence of the temperature gradients during resin infusion on the through-thickness fatigue properties in thick laminates. Coupons from thick laminates cured at different curing rates have been tested in fatigue. The work reports the compression fatigue properties of a thick laminate and relates the results with the curing rate. Safety factors between 1.23 and 1.60 regarding the influence of the curing cycles in thick laminates are reported.

  14. Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source

    NASA Astrophysics Data System (ADS)

    Balint, Ramona; Said-Pullicino, Daniel; Ajmone-Marsan, Franco

    2015-02-01

    Understanding the effect of soil redox conditions on contaminant dynamics is of significant importance for evaluating their lability, mobility and potential transfer to other environmental compartments. Under changing redox conditions, soil properties and constituents such as Fe and Mn (hydr)oxides and organic matter (OM) may influence the behavior of associated metallic elements (MEs). In this work, the redox-driven release and redistribution of Cu between different soil pools was studied in three soils having different contamination sources. This was achieved by subjecting soil columns to a series of alternating reducing and oxidizing cycles under non-limiting C conditions, and assessing their influence on soil pore water, leachate and solid phase composition. Results showed that, in all soils, alternating redox conditions led to an increase in the distribution of Cu in the more labile fractions, consequently enhancing its susceptibility to loss. This was generally linked to the redox-driven cycling of Fe, Mn and dissolved organic matter (DOM). In fact, results suggested that the reductive dissolution of Fe and Mn (hydr)oxides and subsequent reprecipitation as poorly-ordered phases under oxic conditions contributed to the release and mobilization of Cu and/or Cu-containing organometallic complexes. However, the behavior of Cu, as well as the mechanisms controlling Cu release and loss with redox cycling, was influenced by both soil properties (e.g. pH, contents of easily reducible Fe and Mn (hydr)oxides) and source of Cu contamination.

  15. Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source.

    PubMed

    Balint, Ramona; Said-Pullicino, Daniel; Ajmone-Marsan, Franco

    2015-02-01

    Understanding the effect of soil redox conditions on contaminant dynamics is of significant importance for evaluating their lability, mobility and potential transfer to other environmental compartments. Under changing redox conditions, soil properties and constituents such as Fe and Mn (hydr)oxides and organic matter (OM) may influence the behavior of associated metallic elements (MEs). In this work, the redox-driven release and redistribution of Cu between different soil pools was studied in three soils having different contamination sources. This was achieved by subjecting soil columns to a series of alternating reducing and oxidizing cycles under non-limiting C conditions, and assessing their influence on soil pore water, leachate and solid phase composition. Results showed that, in all soils, alternating redox conditions led to an increase in the distribution of Cu in the more labile fractions, consequently enhancing its susceptibility to loss. This was generally linked to the redox-driven cycling of Fe, Mn and dissolved organic matter (DOM). In fact, results suggested that the reductive dissolution of Fe and Mn (hydr)oxides and subsequent reprecipitation as poorly-ordered phases under oxic conditions contributed to the release and mobilization of Cu and/or Cu-containing organometallic complexes. However, the behavior of Cu, as well as the mechanisms controlling Cu release and loss with redox cycling, was influenced by both soil properties (e.g. pH, contents of easily reducible Fe and Mn (hydr)oxides) and source of Cu contamination.

  16. Influence of some crosslinking agents on thermal and mechanical properties of electron beam irradiated polylactide

    NASA Astrophysics Data System (ADS)

    Rytlewski, Piotr; Malinowski, RafaŁ; Moraczewski, Krzysztof; Żenkiewicz, Marian

    2010-10-01

    The aim of this article was to determine and compare the influence of trimethylopropane trimethacylate (TMPTA) and trially isocyanurate (TAIC) crosslinking agents on thermal and mechanical properties of electron beam irradiated polylactide (PLA). The blends were made of PLA mixed with 3 wt% of TMPTA (PLA/TMPTA), and PLA mixed with 3 wt% of TAIC (PLA/TAIC). Injection moulded samples were irradiated with the use of high energy (10 MeV) electron beam at various radiation doses to crosslinking PLA macromolecules. Thermal and mechanical properties were investigated by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile strength, and impact strength measurements. The samples were also characterized by Fourier transform infrared spectroscopy (FTIR). It was found that under the influence of electron irradiation PLA/TMPTA samples underwent degradation while PLA/TAIC samples became crosslinked. Tensile and impact strengths of PLA/TMPTA samples decreased with increasing radiation dose while an enhancement of these properties for PLA/TAIC samples was observed.

  17. Influence of dopant distribution on the plasmonic properties of indium tin oxide nanocrystals.

    PubMed

    Lounis, Sebastien D; Runnerstrom, Evan L; Bergerud, Amy; Nordlund, Dennis; Milliron, Delia J

    2014-05-14

    Doped metal oxide nanocrystals represent an exciting frontier for colloidal synthesis of plasmonic materials, displaying unique optoelectronic properties and showing promise for a variety of applications. However, fundamental questions about the nature of doping in these materials remain. In this article, the strong influence of radial dopant distribution on the optoelectronic properties of colloidal indium tin oxide nanocrystals is reported. Comparing elemental depth-profiling by X-ray photoelectron spectroscopy (XPS) with detailed modeling and simulation of the optical extinction of these nanocrystals using the Drude model for free electrons, a correlation between surface segregation of tin ions and the average activation of dopants is observed. A strong influence of surface segregation of tin on the line shape of the localized surface plasmon resonance (LSPR) is also reported. Samples with tin segregated near the surface show a symmetric line shape that suggests weak or no damping of the plasmon by ionized impurities. It is suggested that segregation of tin near the surface facilitates compensation of the dopant ions by electronic defects and oxygen interstitials, thus reducing activation. A core-shell model is proposed to explain the observed differences in line shape. These results demonstrate the nuanced role of dopant distribution in determining the optoelectronic properties of semiconductor nanocrystals and suggest that more detailed study of the distribution and structure of defects in plasmonic colloidal nanocrystals is warranted.

  18. Influence of physicochemical properties of rice flour on oil uptake of tempura frying batter.

    PubMed

    Nakamura, Sumiko; Ohtsubo, Ken'ichi

    2010-01-01

    The physicochemical properties of rice flour and wheat flour influenced the oil uptake of tempura frying batter. Rice flour was better than wheat flour in the overall quality and crispness of the fried tempura batter. Rice flour resisted oil absorption more than wheat flour, and a higher level of apparent starch amylose and higher consistency/breakdown ratio of the pasting properties led to a lower oil uptake of the batter. Super hard EM10 rice showed the highest apparent amylose content and higher consistency/breakdown ratio than the other flour samples, the batter from EM10 revealing the lowest oil content after frying among all the batters examined. The apparent amylose content, consistency/breakdown ratio and oil absorption index are proposed as useful guides for oil absorption when frying from among the physicochemical properties that influence the oil content of fried batter. Our proposal for the "oil absorption index" could be a simple, although not perfect method for estimating the oil content of batter flour.

  19. Influences of the steam sterilization on the properties of calcium phosphate porous bioceramics.

    PubMed

    Li, Xiangfeng; Guo, Bo; Xiao, Yumei; Yuan, Tun; Fan, Yujiang; Zhang, Xingdong

    2016-01-01

    The influences of steam sterilization on the physicochemical properties of calcium phosphate (Ca-P) porous bioceramics, including β-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP) and hydroxyapatite (HA) are investigated. After being steam sterilized in an autoclave (121 °C for 40 min), the porous bioceramics are dried and characterized. The steam sterilization has no obvious effects on the phase composition, thermal stability, pH value and dissolubility of β-TCP porous bioceramic, but changes its morphology and mechanical strength. Meanwhile, the steam sterilization leads to the significant changes of the morphology, phase composition, pH value and dissolubility of BCP porous bioceramic. The increase of dissolubility and mechanical strength, the decrease of pH value of the immersed solution and partial oriented growth of crystals are also observed in HA porous bioceramic after steam sterilization. These results indicate that the steam sterilization can result in different influences on the physicochemical properties of β-TCP, BCP and HA porous bioceramics, thus the application of the steam sterilization on the three kinds of Ca-P porous bioceramics should be considered carefully based on the above changed properties.

  20. Analysis of the Magnetic Field Influence on the Rheological Properties of Healthy Persons Blood

    PubMed Central

    Nawrocka-Bogusz, Honorata

    2013-01-01

    The influence of magnetic field on whole blood rheological properties remains a weakly known phenomenon. An in vitro analysis of the magnetic field influence on the rheological properties of healthy persons blood is presented in this work. The study was performed on blood samples taken from 25 healthy nonsmoking persons and included comparative analysis of the results of both the standard rotary method (flow curve measurement) and the oscillatory method known also as the mechanical dynamic analysis, performed before and after exposition of blood samples to magnetic field. The principle of the oscillatory technique lies in determining the amplitude and phase of the oscillations of the studied sample subjected to action of a harmonic force of controlled amplitude and frequency. The flow curve measurement involved determining the shear rate dependence of blood viscosity. The viscoelastic properties of the blood samples were analyzed in terms of complex blood viscosity. All the measurements have been performed by means of the Contraves LS40 rheometer. The data obtained from the flow curve measurements complemented by hematocrit and plasma viscosity measurements have been analyzed using the rheological model of Quemada. No significant changes of the studied rheological parameters have been found. PMID:24078918

  1. Influence of Dopant Distribution on the Plasmonic Properties of Indium Tin Oxide Nanocrystals

    SciTech Connect

    Lounis, SD; Runnerstrom, EL; Bergerud, A; Nordlund, D; Milliron, DJ

    2014-05-14

    Doped metal oxide nanocrystals represent an exciting frontier for colloidal synthesis of plasmonic materials, displaying unique optoelectronic properties and showing promise for a variety of applications. However, fundamental questions about the nature of doping in these materials remain. In this article, the strong influence of radial dopant distribution on the optoelectronic properties of colloidal indium tin oxide nanocrystals is reported. Comparing elemental depth-profiling by X-ray photoelectron spectroscopy (XPS) with detailed modeling and simulation of the optical extinction of these nanocrystals using the Drude model for free electrons, a correlation between surface segregation of tin ions and the average activation of dopants is observed. A strong influence of surface segregation of tin on the line shape of the localized surface plasmon resonance (LSPR) is also reported. Samples with tin segregated near the surface show a symmetric line shape that suggests weak or no damping of the plasmon by ionized impurities. It is suggested that segregation of tin near the surface facilitates compensation of the dopant ions by electronic defects and oxygen interstitials, thus reducing activation. A core shell model is proposed to explain the observed differences in line shape. These results demonstrate the nuanced role of dopant distribution in determining the optoelectronic properties of semiconductor nanocrystals and suggest that more detailed study of the distribution and structure of defects in plasmonic colloidal nanocrystals is warranted.

  2. Hydrothermal carbonization of biomass from landscape management - Influence of process parameters on soil properties of hydrochars.

    PubMed

    Röhrdanz, Michael; Rebling, Tammo; Ohlert, Jan; Jasper, Jan; Greve, Thomas; Buchwald, Rainer; von Frieling, Petra; Wark, Michael

    2016-05-15

    Besides pyrolysis the technology of hydrothermal carbonization (HTC) is tested to produce hydrochars for soil improvement. The chemical and physical properties of the hydrochars mainly depend on the feedstock and the process parameters reaction time and process temperature. Systematic investigations on the influences of these process parameters on soil properties of hydrochars like water holding capacity (WHC) and cation exchange capacity (CEC) are missing. In this study, a rush-rich biomass was carbonized within defined HTC process conditions under variation of reaction time and process temperature to produce hydrochars. Analysis of WHC, CEC, the elemental composition and Fourier-transform infrared spectroscopy (FT-IR) were performed to evaluate the influence of HTC process conditions on the pedological hydrochar properties. The results indicated that at increasing reaction severity (reaction time and process temperature) WHC and CEC decreased as well as the elemental O/C ratio. The decrease of WHC and CEC is based on the decrease of the hydrochar surface polarity. However, even the lowest WHC and CEC of investigated hydrochars still exceeded those of pure quartz sand by factors of 5-10. An application of hydrochars produced at severe HTC conditions could improve WHC and CEC of sandy soils. This has to be investigated in further studies. PMID:26974240

  3. Age-related incidence of pineal calcification detected by computed tomography

    SciTech Connect

    Zimmerman, R.A.; Bilaniuk, L.T.

    1982-03-01

    The age-related incidence of detectable pineal calcification in 725 patients (age range, newborn-20 yrs) suggests that there is a relationship between calcification and the hormonal role played by the pineal gland in the regulation of sexual development. Pineal calcification (demonstrated by computed tomography (CT) on 8-mm-thick sections) in patients less than 6 years old should be looked upon with suspicion, and follow-up CT should be considered to exclude the possible development of a pineal neoplasm.

  4. Progression to calcific mitral stenosis in end-stage renal disease.

    PubMed

    D'Cruz, I A; Madu, E C

    1995-12-01

    A 59-year-old man with end-stage renal disease and on hemodialysis had neither mitral stenosis nor mitral calcification on echo-Doppler examination in 1989, but had extensive mitral calcification and definite mitral stenosis on conventional and transesophageal echocardiography in 1994. The left ventricle had marked concentric hypertrophy. To our knowledge this is the first documentation of the development of calcific mitral stenosis in end-stage renal disease revealed by serial echo-Doppler studies.

  5. Calcification and airway stenosis in a child with chondrodysplasia calcificans punctata

    PubMed Central

    Goussard, Pierre; Andronikou, Savvas; Semakula-Katende, Namakula S; Gie, Robert

    2014-01-01

    Calcification of the airways is rarely seen in children. A male baby was born at 34 weeks with severe respiratory distress. Intubation was difficult with severe hypercarbia after intubation. Chest radiography demonstrated calcification in the tracheobronchial tree and this was confirmed with Chest CT scan. Flexible bronchoscopy confirmed long-segment funnel tracheal stenosis with visible calcifications in the trachea and bronchi. Chondrodysplasia punctata was diagnosed based on the clinical and radiological findings. PMID:25246461

  6. Irradiating of Bulk Soybeans: Influence on Their Functional and Sensory Properties for Soyfood Processing

    NASA Technical Reports Server (NTRS)

    Chia, Chiew-Ling; Wilson, Lester A.; Boylston, Terri; Perchonok, Michele; French, Stephen

    2006-01-01

    Soybeans were chosen for lunar and planetary missions, where soybeans will be supplied in bulk or grown locally, due to their nutritive value and ability to produce oil and protein for further food applications. However, soybeans must be processed into foods prior to consumption. Radiation that soybeans would be exposed to during bulk storage prior to and during a Mars mission may influence their germination and functional properties. The influence of radiation includes the affect of surface pasteurization to ensure the astronauts safety from food-borne illnesses (HACCP, CCP), and the affect of the amount of radiation the soybeans receive during a Mars mission. Decreases in the amount of natural antioxidants free radical formation, and oxidation-induced changes in the soybean will influence the nutritional value, texture, color, and aroma of soyfoods. The objective of this study was to determine the influence of pasteurization and sterilization surface radiation on whole soybeans using gamma and electron beam radiation. The influence of 0, 1, 5, 10, and 30kGy on microbial load, germination rate, ease of processing, and quality of soymilk and tofu were determined. Surface radiation of whole dry soybeans using electron beam or gamma rays from 1-30kGy did provide microbial safety for the astronauts. However, the lower dose levels had surviving yeasts and molds. These doses caused oxidative changes that resulted in soymilk and tofu with rancid aromas. GC-MS of the aroma compounds using SPME Headspace confirmed the presence of lipid oxidation compounds. Soybean germination ability was reduced as radiation dosage increased. While lower doses may reduce these problems, the ability to insure microbial safety of bulk soybeans will be lost. Counter measures could include vacuum packaging, nitrogen flushing, added antioxidants, and radiating under freezing conditions. Doses below 1kGy need to be investigated further to determine the influence of the radiation encountered

  7. Globular adiponectin reduces vascular calcification via inhibition of ER-stress-mediated smooth muscle cell apoptosis

    PubMed Central

    Lu, Yan; Bian, Yunfei; Wang, Yueru; Bai, Rui; Wang, Jiapu; Xiao, Chuanshi

    2015-01-01

    Objective: This study aims to explore the mechanism of globular adiponectin inhibiting vascular calcification. Methods: We established drug-induced rat vascular calcification model, globular adiponectin was given to observe the effect of globular Adiponectin on the degree of calcification. The markers of vascular calcification and apoptosis were also investigated. Meanwhile, the in vitro effect of globular Adiponectin on vascular calcification was also evaluated using primary cultured rat vascular smooth muscle cells. Results: We found that globular adiponectin could inhibit drug-induced rat vascular calcification significantly in vivo. The apoptosis of vascular smooth muscle cells was also reduced. The possible mechanism could be the down-regulation of endoplasmic reticulum stress by globular adiponectin. Experiments in primary cultured vascular smooth muscle cells also confirmed that globular adiponectin could reduce cell apoptosis to suppress vascular calcification via inhibition of endoplasmic reticulum stress. Conclusions: This study confirmed that globular adiponectin could suppress vascular calcification; one of the mechanisms could be inhibition of endoplasmic reticulum stress to reduce cell apoptosis. It could provide an effective method in the therapy of vascular calcification-associated diseases. PMID:26045760

  8. Molecular Mechanisms of Vascular Calcification in Chronic Kidney Disease: The Link between Bone and the Vasculature

    PubMed Central

    Byon, Chang Hyun

    2015-01-01

    Vascular calcification is highly prevalent in patients with chronic kidney disease (CKD) and increases mortality in those patients. Impaired calcium and phosphate homeostasis, increased oxidative stress, and loss of calcification inhibitors have been linked to vascular calcification in CKD. Additionally, impaired bone may perturb serum calcium/phosphate and their key regulator, parathyroid hormone, thus contributing to increased vascular calcification in CKD. Therapeutic approaches for CKD, such as phosphate binders and bisphosphonates, have been shown to ameliorate bone loss as well as vascular calcification. The precise mechanisms responsible for vascular calcification in CKD and the contribution of bone metabolism to vascular calcification have not been elucidated. This review discusses the role of systemic uremic factors and impaired bone metabolism in the pathogenesis of vascular calcification in CKD. The regulation of the key osteogenic transcription factor Runt-related transcription factor 2 (Runx2) and the emerging role of Runx2-dependent receptor activator of nuclear factor kappa-B ligand (RANKL) in vascular calcification of CKD are emphasized. PMID:25947259

  9. [Biomarkers of vascular calcifications: the osteoprotegerin/RANK/RANK L axis].

    PubMed

    Bargnoux, Anne-Sophie; Morena, Marion; Arnaud, Josiane; Cavalier, Étienne; Zaoui, Philippe; Delanaye, Pierre; Cristol, Jean-Paul

    2015-01-01

    A better knowledge of physiopathologic phenomena responsible for vascular mineralization leads to emerging biological markers of vascular calcifications. In calcified arteries, the presence of bone matrix as well as osteoblast cells suggest that vascular calcification is an active and highly regulated process. The OPG/RANK/RANKL system is clearly of central significance in controlling vascular calcifications as in bone metabolism. Converging results suggest that circulating OPG determination should be a relevant marker of calcifications. The OPG/RANK/RANKL pathway also represents a potential therapeutic target in diseases associated with high bone resorption.

  10. Identification of Calcification with Magnetic Resonance Imaging Using Susceptibility-Weighted Imaging: A Case Study

    PubMed Central

    Wu, Zhen; Mittal, Sandeep; Kish, Karl; Yu, Yingjian; Hu, J.; Haacke, E. Mark

    2008-01-01

    Susceptibility weighted imaging (SWI) is a new MRI technique that can identify calcification by using phase images. We present a single case with a partially calcified oligodendroglioma, multiple calcified cysticercosis lesions, and multiple physiologic calcifications in the same patient. SWI phase images and computed tomography (CT) images are compared. SWI phase images showed the same calcified lesions as shown on CT and sometimes some new calcifications. Our conclusion is that SWI filtered phase images can identify calcifications as well as CT in this case. PMID:19097156

  11. Harnessing osteopontin and other natural inhibitors to mitigate ectopic calcification of bioprosthetic heart valve material

    NASA Astrophysics Data System (ADS)

    Ohri, Rachit

    Dystrophic calcification has been the long-standing major cause of bioprosthetic heart valve failure, and has been well studied in terms of the underlying causative mechanisms. Such understanding has yielded several anti-calcification strategies involving biomaterial modification at the preparation stage: chemical alteration, extraction of calcifiable components, or material modification with small-molecule anti-calcific agents. However, newer therapeutic opportunities are offered by the growing illustration of the pathology as a dynamic, actively regulated process involving several gene products, such as osteopontin (OPN), matrix-gla protein (MGP) and glycosaminoglycans (GAGs). Osteopontin, a multi-functional matricellular glycosylated phosphoprotein has emerged as a prime candidate for the role of an in vivo inhibitor of ectopic calcification with two putative mechanisms: crystal poisoning and mineral-dissolution. The full therapeutic realization of its potential necessitates a better understanding of the mechanisms of anti-calcification by osteopontin, as well as appropriate in vivo models in which to evaluate its efficacy, potency and molecular mechanisms. In this work, we pursued the development and characterization of a reliable in vivo model with the OPN-null mouse to simulate the calcification of bioprosthetic valve material, namely glutaraldehyde-fixed bovine pericardium (GFBP) tissue. Subsequently, we used the calcification model to evaluate hypotheses based on the anti-calcific potential of osteopontin. Several modes of administering exogenous OPN to the implant site in OPN-null mice were explored, including soluble injected OPN, OPN covalently immobilized on the biomaterial, and OPN adsorbed onto the biomaterial. An investigation of the structure-function aspects of the anti-calcific ability of OPN was also pursued in the in vivo model. The OPN-null mouse was also used as an in vivo test-bed to evaluate the anti-calcific potential of other biomolecules

  12. Role of extracellular vesicles in de novo mineralization: an additional novel mechanism of cardiovascular calcification.

    PubMed

    New, Sophie E P; Aikawa, Elena

    2013-08-01

    Extracellular vesicles are membrane micro/nanovesicles secreted by many cell types into the circulation and the extracellular milieu in physiological and pathological conditions. Evidence suggests that extracellular vesicles, known as matrix vesicles, play a role in the mineralization of skeletal tissue, but emerging ultrastructural and in vitro studies have demonstrated their contribution to cardiovascular calcification as well. Cells involved in the progression of cardiovascular calcification release active vesicles capable of nucleating hydroxyapatite on their membranes. This review discusses the role of extracellular vesicles in cardiovascular calcification and elaborates on this additional mechanism of calcification as an alternative pathway to the currently accepted mechanism of biomineralization via osteogenic differentiation.

  13. Regulation of the sodium-phosphate cotransporter Pit-1 and its role in vascular calcification.

    PubMed

    Gonzalez, Magdalena; Martínez, Rafael; Amador, Cristián; Michea, Luis

    2009-10-01

    Vascular calcification is caused by the deposition of basic calcium phosphate crystals in blood vessels, myocardium, and/or cardiac valves. Calcification decreases artery wall compliance, and arterial calcification is associated to mortality in hyperphosphatemic renal failure and diabetes mellitus. The calcification of the tunica media characterizes the arteriosclerosis observed with age, diabetes and end stage-renal disease, and it can develop independently from intima calcification. As part of the vascular calcification mechanism, vascular smooth muscle cells (VSMC) experience a transition from a contractile to an osteochondrogenic phenotype and a sequence of molecular events that are typical of endochondral ossification. The current evidence indicates a key role of increased phosphate uptake by VSMC for calcification, which supplies the substrate for hydroxyapatite formation and could trigger or potentiate VSMC transdiferentiation. The present review analyzes the sodium-phosphate cotransporter Pit-1, which is implicated in calcification. On the basis of the available data obtained in the study of vascular and osteoblastic experimental models, we discuss potential regulatory mechanisms that could lead to increased sodium-dependent phosphate uptake in vascular calcification. PMID:19485893

  14. Influence of fuels, weather and the built environment on the exposure of property to wildfire.

    PubMed

    Penman, Trent D; Collins, Luke; Syphard, Alexandra D; Keeley, Jon E; Bradstock, Ross A

    2014-01-01

    Wildfires can pose a significant risk to people and property. Billions of dollars are spent investing in fire management actions in an attempt to reduce the risk of loss. One of the key areas where money is spent is through fuel treatment--either fuel reduction (prescribed fire) or fuel removal (fuel breaks). Individual treatments can influence fire size and the maximum distance travelled from the ignition and presumably risk, but few studies have examined the landscape level effectiveness of these treatments. Here we use a Bayesian Network model to examine the relative influence of the built and natural environment, weather, fuel and fuel treatments in determining the risk posed from wildfire to the wildland-urban interface. Fire size and distance travelled was influenced most strongly by weather, with exposure to fires most sensitive to changes in the built environment and fire parameters. Natural environment variables and fuel load all had minor influences on fire size, distance travelled and exposure of assets. These results suggest that management of fuels provided minimal reductions in risk to assets and adequate planning of the changes in the built environment to cope with the expansion of human populations is going to be vital for managing risk from fire under future climates.

  15. Influence of Fuels, Weather and the Built Environment on the Exposure of Property to Wildfire

    PubMed Central

    Penman, Trent D.; Collins, Luke; Syphard, Alexandra D.; Keeley, Jon E.; Bradstock, Ross A.

    2014-01-01

    Wildfires can pose a significant risk to people and property. Billions of dollars are spent investing in fire management actions in an attempt to reduce the risk of loss. One of the key areas where money is spent is through fuel treatment – either fuel reduction (prescribed fire) or fuel removal (fuel breaks). Individual treatments can influence fire size and the maximum distance travelled from the ignition and presumably risk, but few studies have examined the landscape level effectiveness of these treatments. Here we use a Bayesian Network model to examine the relative influence of the built and natural environment, weather, fuel and fuel treatments in determining the risk posed from wildfire to the wildland-urban interface. Fire size and distance travelled was influenced most strongly by weather, with exposure to fires most sensitive to changes in the built environment and fire parameters. Natural environment variables and fuel load all had minor influences on fire size, distance travelled and exposure of assets. These results suggest that management of fuels provided minimal reductions in risk to assets and adequate planning of the changes in the built environment to cope with the expansion of human populations is going to be vital for managing risk from fire under future climates. PMID:25360741

  16. Influence of fuels, weather and the built environment on the exposure of property to wildfire

    USGS Publications Warehouse

    Penman, Trent D.; Collins, Luke S.; Syphard, Alexandra D.; Keeley, Jon E.; Bradstock, Ross A.

    2014-01-01

    Wildfires can pose a significant risk to people and property. Billions of dollars are spent investing in fire management actions in an attempt to reduce the risk of loss. One of the key areas where money is spent is through fuel treatment – either fuel reduction (prescribed fire) or fuel removal (fuel breaks). Individual treatments can influence fire size and the maximum distance travelled from the ignition and presumably risk, but few studies have examined the landscape level effectiveness of these treatments. Here we use a Bayesian Network model to examine the relative influence of the built and natural environment, weather, fuel and fuel treatments in determining the risk posed from wildfire to the wildland-urban interface. Fire size and distance travelled was influenced most strongly by weather, with exposure to fires most sensitive to changes in the built environment and fire parameters. Natural environment variables and fuel load all had minor influences on fire size, distance travelled and exposure of assets. These results suggest that management of fuels provided minimal reductions in risk to assets and adequate planning of the changes in the built environment to cope with the expansion of human populations is going to be vital for managing risk from fire under future climates.

  17. Influence of substrate miscut angle on surface morphology and luminescence properties of AlGaN

    SciTech Connect

    Kusch, Gunnar Edwards, Paul R.; Bruckbauer, Jochen; Martin, Robert W.; Li, Haoning; Parbrook, Peter J.; Sadler, Thomas C.

    2014-03-03

    The influence of substrate miscut on Al{sub 0.5}Ga{sub 0.5} N layers was investigated using cathodoluminescence (CL) hyperspectral imaging and secondary electron imaging in an environmental scanning electron microscope. The samples were also characterized using atomic force microscopy and high resolution X-ray diffraction. It was found that small changes in substrate miscut have a strong influence on the morphology and luminescence properties of the AlGaN layers. Two different types are resolved. For low miscut angle, a crack-free morphology consisting of randomly sized domains is observed, between which there are notable shifts in the AlGaN near band edge emission energy. For high miscut angle, a morphology with step bunches and compositional inhomogeneities along the step bunches, evidenced by an additional CL peak along the step bunches, are observed.

  18. The nanomechanical properties of lipid membranes are significantly influenced by the presence of ethanol.

    PubMed

    Stetter, Frank W S; Hugel, Thorsten

    2013-03-01

    Ethanol has a profound impact on biological systems and is moreover used in various medical and nonmedical applications. Its interaction with the lipid part of biological membranes has been the subject of intensive studies, but surprisingly, to our knowledge, no study has examined the influence of ethanol on lipid bilayer nanomechanics. We performed atomic force microscopy-based measurements to assess the influence of ethanol on the nanomechanical properties of fluid supported lipid bilayers. Ethanol significantly reduces membrane stability, bilayer thickness, Young's modulus, area stretch modulus, and bending stiffness. Altogether, our data suggest that ethanol addition to supported lipid bilayers supports both the hydrophobic and the hydrophilic permeation pathways by a decrease of bilayer thickness and reduced stability, respectively.

  19. Pyocyanin facilitates extracellular DNA binding to Pseudomonas aeruginosa influencing cell surface properties and aggregation.

    PubMed

    Das, Theerthankar; Kutty, Samuel K; Kumar, Naresh; Manefield, Mike

    2013-01-01

    Pyocyanin is an electrochemically active metabolite produced by the human pathogen Pseudomonas aeruginosa. It is a recognized virulence factor and is involved in a variety of significant biological activities including gene expression, maintaining fitness of bacterial cells and biofilm formation. It is also recognized as an electron shuttle for bacterial respiration and as an antibacterial and antifungal agent. eDNA has also been demonstrated to be a major component in establishing P. aeruginosa biofilms. In this study we discovered that production of pyocyanin influences the binding of eDNA to P. aeruginosa PA14 cells, mediated through intercalation of pyocyanin with eDNA. P. aeruginosa cell surface properties including cell size (hydrodynamic diameter), hydrophobicity and attractive surface energies were influenced by eDNA in the presence of pyocyanin, affecting physico-chemical interactions and promoting aggregation. A ΔphzA-G PA14 mutant, deficient in pyocynain production, could not bind with eDNA resulting in a reduction in hydrodynamic diameter, a decrease in hydrophobicity, repulsive physico-chemical interactions and reduction in aggregation in comparison to the wildtype strain. Removal of eDNA by DNase I treatment on the PA14 wildtype strain resulted in significant reduction in aggregation, cell surface hydrophobicity and size and an increase in repulsive physico-chemical interactions, similar to the level of the ΔphzA-G mutant. The cell surface properties of the ΔphzA-G mutant were not affected by DNase I treatment. Based on these findings we propose that pyocyanin intercalation with eDNA promotes cell-to-cell interactions in P. aeruginosa cells by influencing their cell surface properties and physico-chemical interactions. PMID:23505483

  20. The influence of the property of random coded patterns on fluctuation-correlation ghost imaging

    NASA Astrophysics Data System (ADS)

    Wang, Chenglong; Gong, Wenlin; Shao, Xuehui; Han, Shensheng

    2016-06-01

    According to the reconstruction feature of fluctuation-correlation ghost imaging (GI), we define a normalized characteristic matrix and the influence of the property of random coded patterns on GI is investigated based on the theory of matrix analysis. Both simulative and experimental results demonstrate that for different random coded patterns, the quality of fluctuation-correlation GI can be predicted by some parameters extracted from the normalized characteristic matrix, which suggests its potential application in the optimization of random coded patterns for GI system.

  1. Influence of Space-Flight Factors on the Properties of Microorganisms, Producers of Biologically Active Substances

    NASA Astrophysics Data System (ADS)

    Krasheninnikova, T. K.; Kanaeva, E. N.; Ukraintsev, A. D.; Smolyanaya, G. L.; Kuznetsov, N. V.; Panasyuk, M. I.; Shcherbakov, G. Ya.

    2001-07-01

    The following substances were isolated under the influence of space-flight factors in cosmic experiments aboard the Mirorbital station: an MIB-90 monoisolant, which is distinguished by its morphological and biochemical properties and enhanced productivity, was isolated from the Bacillus thuringiensis ssp. Kurstaki var. Z-52culture, which is a producer of the plant protection agent Lepidocide; and MIA-74 and MIP-89 monoisolants, which are highly active toward heavy petroleum fractions (C23 C33), were isolated from the Arthrobacter OC-1culture, which is a producer of biodegradants for petroleum.

  2. Influence of dipolar interaction on magnetic properties of ultrafine ferromagnetic particles

    PubMed

    Garcia-Otero; Porto; Rivas; Bunde

    2000-01-01

    We use Monte Carlo simulations to study the influence of dipolar interaction and polydispersity on the magnetic properties of single-domain ultrafine ferromagnetic particles. From the zero field cooling (ZFC)/field cooling (FC) simulations we observe that the blocking temperature T(B) clearly increases with increasing strength of interaction, but it is almost not effected by a broadening of the distribution of particle sizes. While the dependence of the ZFC/FC curves on interaction and cooling rate are reminiscent of a spin glass transition at T(B), the relaxational behavior of the magnetic moments below T(B) is not in accordance with the picture of cooperative freezing.

  3. [Influence of UV-light and dexamethasone on functional properties of lymphocytes and neutrophils].

    PubMed

    Artiukhov, V G; Basharina, O V; Lialina, I E; Maslov, O V

    2005-01-01

    UV-light and dexamethasone influence on functional properties of lymphocytes and neutrophils of peripherical donors' blood was studied. An increase of phagocytic activity of neutrophils was observed after their incubation with photomodified lymphocytes. It was found that UV-irradiation of lymphocytes activated synthesis of interleukines 1beta and 2. Dexamethasone presence in lymphocyte suspension inhibited the synthesis of the studied cytokines, especially by the incubation with photomodified cells. It was shown by the method of fluorescent labels that UV-irradiation improved interaction between dexamethasone and cell membrane.

  4. The influence of yarn treatment on the tensile properties of biocomposites

    NASA Astrophysics Data System (ADS)

    Širvaitienė, Anne; Jankauskaitė, Virginija; Bekampienė, Paulė; Sankauskaitė, Audronė

    2012-07-01

    The aim of this work was to investigate the influence of cotton and linen yarns treatments at different hierarchical levels on the biocomposite tensile properties. The biodegradable poly(lactic acid) (PLA) resin was used as the matrix polymer. The water based mercerization and low pressure plasma treatment were applied for chemical modification of yarns macro- and microfibrils. To improve fiber orientation of fibre bundles and single fibers the pretension of yarn was used. It was obtained that the most efficient is the complex yarns treatment, plasma treatment with subsequent pre-tension, where especially notable was the positive effect of low-pressure plasma.

  5. Optical properties of VO2 films at the phase transition: Influence of substrate and electronic correlations

    NASA Astrophysics Data System (ADS)

    Peterseim, Tobias; Dressel, Martin; Dietrich, Marc; Polity, Angelika

    2016-08-01

    Thin films of VO2 on different substrates, Al2O3 and SiO2/Si, have been prepared and characterized from room temperature up to 360 K. From the band structure in the rutile metallic phase and in the monoclinic insulating phase, the optical properties are calculated and compared with reflection measurements performed as a function of temperatures. Various interband transitions can be assigned and compared with previous speculations. We extract the parameters of the metallic charge carriers that evolve upon crossing the insulator-to-metal phase transition and find effects by the substrate. The influence of electronic correlations becomes obvious at the phase transition.

  6. Influence of binder type on interacting variables acting on mechanical properties of a sulfadimidine tablet formulation.

    PubMed

    Alebiowu, G; Ojeleye, O O

    2007-01-01

    A study of the quantitative effect of type of binder (N), applied pressure (P), and granular size (G) on two mechanical properties-tensile strength (TS) and brittle fracture index (BFI) - of a sulfadimidine tablet formulation has been carried out by using a 2(3) factorial experimental design. The results obtained from this work suggest that P exhibited the largest individual effect on TS and BFI. It is also seen from this work that the nature of binders in combination affects the influence that P and G had on the TS or BFI.

  7. Influence of length of hot soak of melt on properties of lithium greases with additives

    SciTech Connect

    El'-Shaban, I.; Fuks, I.G.; Safi, M.; Uvarova, E.M.; Yaroshevich, S.V.

    1983-11-01

    An extension of the time during which the melt is hot-soaked at the maximum cooking temperature tends to improve the dispersion of the thickening agent in the oil but also increases oxidation and evaporation. This paper investigates the influence of hot-soaking the soap/oil melt of Li greases on the effectiveness of selected additives. Extending the hot-soak time in manufacturing Li greases leads to oxidation as well as accumulation of oxygen-containing substances in the grease. The end result is poorer properties of the grease.

  8. Influence of erbium doping on phase transition and optical properties of strontium barium niobate

    NASA Astrophysics Data System (ADS)

    Oprea, Isabella-Ioana; Voelker, Uwe; Niemer, Alexander; Pankrath, Rainer; Podlozhenov, Sergey; Betzler, Klaus

    2009-11-01

    The optical properties of erbium impurities in strontium barium niobate are investigated measuring optical absorption and emission in the visible and near infrared spectral region. For the main fluorescence band at 1.55 μm, an anomalous dependence of the fluorescence decay time on dopant concentration is found which, however, can be consistently explained by reabsorption effects. A Judd-Ofelt analysis of the absorption spectra together with an appropriate analysis of the reabsorption yields a radiative quantum efficiency of approximately 60%. In addition, erbium dopants are shown to efficiently influence the phase transition temperature of strontium barium niobate.

  9. Solidification rate influence on orientation and mechanical properties of MAR-M-246+Hf

    NASA Technical Reports Server (NTRS)

    Hamilton, D.

    1983-01-01

    The influence of solidification rates on the orientation and mechanical properties of MAR-M-246+Hf was studied. The preferred orientation was found to be (001) for single crystals, with all samples with 45 degrees of (001). Tensile tests were performed at room temperature. The anisotropy of directionally solidified MAR-M-246+Hf was demonstrated by gage section deformation. Dendrite arm spacing and crystal growth were found to depend on solidification rates and source material conditions. The greatest strength occurred at lower solidification rates. Some single crystals were grown by control of growth rates without seeding.

  10. Surface coating influence on elastic properties of spruce wood by means of holographic vibration mode visualization

    NASA Astrophysics Data System (ADS)

    Bongova, M.; Urgela, Stanislav

    1999-07-01

    Physicoacoustical properties of wood influenced by surface coating are studied by modal analysis. Resonant spruce plates were coated by stain, nitrocellulose varnish, special violin paint and shellac. The modal testing was performed by electronic speckle pattern interferometry. For this purpose, equipment called VIBROVIZER was used. The collected values of physicoacoustical characteristics (density, Young's modulus, acoustic constant) were compared using the graphic plots of data. The 3D plots help to evaluate wooden plates from a viewpoint of the quality control. This fact offers new opportunity for musical instrument manufacturers.

  11. The Influence of Structural Features of Particles on their Light Scattering Properties

    NASA Astrophysics Data System (ADS)

    Theilheim, K. O.

    The theory of the scattering of light by ensembles of particles with ir regular shape is of interest in the context of interstellar and interplanetary dust grains and particles associated with comets or observed in aerosols and hydrosols. The scattering properties of homogeneous particles are determined by both geometrical features and chemical composition as represented by the complex frequency dependent index of refraction. We have performed a systematic investigation on the former aspect, namely the influence of structural features of the surface of large dielectric particles on their light scattering properties. The geometrical surface structure will be discussed in terms of macro roughness and micro roughness as two limiting cases of a more general type of roughness. Some results will also be presented for composite roughness models. Finally I will discuss preliminary results of a scattering theory applicable to ensembles of particles with irregular shape and arbitrary size based on the method of perturbed boundary conditions.

  12. The influence of processing on microstructure and properties of iron aluminides

    SciTech Connect

    Wright, R.N.; Wright, J.K.

    1995-08-01

    An Fe-28%Al alloy containing 5% Cr has been synthesized by reaction of elemental powders, followed by consolidation using hot isostatic pressing or hot extrusion. The resulting materials are fully dense, homogeneous, and have a grain size of less than 5{mu}m. Processing strongly influences the propensity toward secondary recrystallization. While HIPped material is extremely resistant to grain growth, under some circumstances hot extruded material undergoes secondary recrystallization, resulting in grain sizes as large as 25 millimeters. Elevated temperature tensile properties and strain rate sensitivities are reported for fine and very coarse grained materials. Grain boundary sliding is not a significant deformation mode for any of the materials. The properties are compared to those of Fe{sub 3}Al processed from conventional hot extruded prealloyed. powder. It has been found that the reaction synthesized materials generally have superior elevated temperature tensile strength.

  13. Influence of oxygen impurity on electronic properties of carbon and boron nitride nanotubes: A comparative study

    SciTech Connect

    Singh, Ram Sevak

    2015-11-15

    Influence of oxygen impurity on electronic properties of carbon and boron nitride nanotubes (CNTs and BNNTs) is systematically studied using first principle calculations based on density functional theory. Energy band structures and density of states of optimized zigzag (5, 0), armchair (3, 3), and chiral (4, 2) structures of CNT and BNNT are calculated. Oxygen doping in zigzag CNT exhibits a reduction in metallicity with opening of band gap in near-infrared region while metallicity is enhanced in armchair and chiral CNTs. Unlike oxygen-doped CNTs, energy bands are drastically modulated in oxygen-doped zigzag and armchair BNNTs, showing the nanotubes to have metallic behaviour. Furthermore, oxygen impurity in chiral BNNT induces narrowing of band gap, indicating a gradual modification of electronic band structure. This study underscores the understanding of different electronic properties induced in CNTs and BNNTs under oxygen doping, and has potential in fabrication of various nanoelectronic devices.

  14. Influence of Heat Treatment Conditions on the Properties of Vanadium Oxide Thin Films for Thermochromic Applications.

    PubMed

    Kim, Donguk; Kwon, Samyoung; Park, Young; Boo, Jin-Hyo; Nam, Sang-Hun; Joo, Yang Tae; Kim, Minha; Lee, Jaehyeong

    2016-05-01

    In present work, the effects of the heat treatment on the structural, optical, and thermochromic properties of vanadium oxide films were investigated. Vanadium dioxide (VO2) thin films were deposited on glass substrate by reactive pulsed DC magnetron sputtering from a vanadium metal target in mixture atmosphere of argon and oxygen gas. Various heat treatment conditions were applied in order to evaluate their influence on the crystal phases formed, surface morphology, and optical properties. The films were characterized by an X-ray diffraction (XRD) in order to investigate the crystal structure and identify the phase change as post-annealing temperature of 500-600 degrees C for 5 minutes. Surface conditions of the obtained VO2(M) films were analyzed by field emission scanning electron microscopy (FE-SEM) and the semiconductor-metal transition (SMT) characteristics of the VO2 films were evaluate by optical spectrophotometry in the UV-VIS-NIR, controlling temperature of the films.

  15. Characteristics of wood ash and influence on soil properties and nutrient uptake: an overview.

    PubMed

    Demeyer, A; Voundi Nkana, J C; Verloo, M G

    2001-05-01

    Wood industries and power plants generate enormous quantities of wood ash. Disposal in landfills has been for long a common method for removal. New regulations for conserving the environment have raised the costs of landfill disposal and added to the difficulties for acquiring new sites for disposal. Over a few decades a number of studies have been carried out on the utilization of wood ashes in agriculture and forestry as an alternative method for disposal. Because of their properties and their influence on soil chemistry the utilization of wood ashes is particularly suited for the fertility management of tropical acid soils and forest soils. This review principally focuses on ash from the wood industry and power plants and considers its physical, chemical and mineralogical characteristics, its effect on soil properties, on the availability of nutrient elements and on the growth and chemical composition of crops and trees, as well as its impact on the environment. PMID:11272014

  16. Influence of morphological transformation on luminescence properties of europium-doped gadolinium oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Dondapati, Hareesh; Holloway, Terence; Cao, Wei; Kar, Arik; Patra, Amitava; Pradhan, Aswini K.

    2010-09-01

    Low dimensional europium (Eu3+)-doped gadolinium oxide (Gd2O3) lanthanide nanostructures are synthesized by an effective and simple coprecipitation process followed by subsequent heat treatments. Transmission electron microscope (TEM) images indicate Eu3+-doped Gd2O3 nanostructures undergo significant morphological changes from nanorods to nanoparticles during thermal treatments. Nanostructures with different morphology, including nanotubes, strongly influence the photoluminescence properties. The dependence of luminescence lifetime on morphological nature of the nanostructures demonstrates that the one dimensional nanostructures such as nanorods and nanotubes have higher emission intensity with shorter lifetime. Our analysis suggests that the morphological transformation of the nanostructures plays the most important role in the behavior of radiative and nonradiative relaxation mechanisms, resulting in the overall photoluminescence properties.

  17. Influence of tragacanth gum in egg white based bioplastics: Thermomechanical and water uptake properties.

    PubMed

    López-Castejón, María Luisa; Bengoechea, Carlos; García-Morales, Moisés; Martínez, Inmaculada

    2016-11-01

    This study aims to extend the range of applications of tragacanth gum by studying its incorporation into bioplastics formulation, exploring the influence that different gum contents (0-20wt.%) exert over the thermomechanical and water uptake properties of bioplastics based on egg white albumen protein (EW). The effect of plasticizer nature was also evaluated through the modification of the water/glycerol ratio within the plasticizer fraction (fixed at 40wt.%). The addition of tragacanth gum generally yielded an enhancement of the water uptake capacity, being doubled at the highest content. Conversely, presence of tragacanth gum resulted in a considerable decrease in the bioplastic mechanical properties: both tensile strength and maximum elongation were reduced up to 75% approximately when compared to the gum-free system. Ageing of selected samples was also studied, revealing an important effect of storage time when tragacanth gum is present, possibly due to its hydrophilic character.

  18. Influence of TESG layer viscoelasticity on the imaging properties of microlenses

    NASA Astrophysics Data System (ADS)

    Vasiljević, Darko; Murić, Branka; Pantelić, Dejan; Panić, Bratimir

    2012-05-01

    Microlenses were produced by the irradiation of a layer of tot'hema and eosin sensitized gelatin (TESG) with laser light (second harmonic Nd:YAG, 532 nm). For this research, eight microlenses were written on a dog-bone-shaped TESG layer. After production, microlenses were uniaxially stretched on a tensile testing machine. Each microlens had different amounts of strain (0, 30, 60, 80, 120, 140, 180 and 240% strain). The influence of TESG layer extensibility on the imaging properties of microlenses was characterized by calculating the root mean square wavefront aberration, the modulation transfer function and the geometrical spot diagram. All microlenses had very good imaging properties and the microlens with 0% strain had diffraction-limited performance.

  19. Mesomeric Effects of Graphene Modified with Diazonium Salts: Substituent Type and Position Influence its Properties.

    PubMed

    Bouša, Daniel; Jankovský, Ondřej; Sedmidubský, David; Luxa, Jan; Šturala, Jiří; Pumera, Martin; Sofer, Zdeněk

    2015-12-01

    In the last decade, graphene and graphene derivatives have become some of the most intensively studied materials. Tuning of the electronic and electrochemical properties of graphene is of paramount importance. In this study, six diazonium-modified graphenes containing different functional groups according to the diazonium salt precursor were investigated. These diazonium moieties have a strong mesomeric (resonance) effect and act as either electron-donating or -withdrawing species. Different graphene precursors, such as thermally and chemically reduced graphenes were studied. All the products were characterized in detail by elemental combustion analysis, FTIR spectroscopy, Raman spectroscopy, high-resolution X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry. Resistivity and zeta potential measurements were consistent with theoretical (DFT) calculations. The results show that chemical modification of graphene by diazotation strongly influences its properties, creating a huge application potential in microelectronics, energy storage and conversion devices, and electrocatalysis.

  20. Influence of self-assembly regenerated silk fibroin nanofibers on the properties of electrospun materials.

    PubMed

    Zhao, Huijing; Ren, Xia; Zhang, Yi; Huang, Lei

    2015-01-01

    In this study, self-assembly regenerated silk fibroin (RSF) nanofibers were prepared and observed by Atomic Force Microscope (AFM). Then RSF films containing nanospheres and nanofibers were prepared and dissolved with poly (L-lactide-co-ε-caprolactone) (PLCL) with a blending ratio of 30/70 in hexafluoro-2-propanol (HFIP). In order to determine whether different nanostructures in the solution influence the morphological, structural, and mechanical properties of the final electrospun materials, flat membranes were prepared and characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FT-IR), and mechanical testing. The secondary structure of as-spun materials with RSF nanofibers were not changed, however, the diameter of electrospun fibers decreased and tensile strength and elongation at breaks increased. Electrospun materials with RSF nanofibers have the potential to be used for skin, cartilage, and blood vessels because of their biocompatibility and improved mechanical properties.

  1. The influence of granulated powder temporary organics composition on ceramic structure and properties

    NASA Astrophysics Data System (ADS)

    Veselov, S.; Belousova, N.; Zamyatina, A.; Sokolov, I.; Felofyanova, A.

    2016-04-01

    The influence of granulated powder binder/plasticizer ratio on epy microstructure and properties of sintered ceramic specimens is shown using submicron alumina. The fracture mode, microstructure and properties analyses of a green part and sintered samples obtained with different organic ratio contained in granulated powder are presented. It was stated that the usage of PVA (grade 16/1) and PEG 400 at an equal ratio results in a uniform distribution of granulated powder in a die and high green density. It is also shown that an addition of 2 wt. % of PVA and 2 wt. % of PEG400 into granules of ceramic press powder allows obtaining A1203 ceramic with apparent density of about 3,91 g/cm3 and bending strength of up to 410 MPa.

  2. Influence of self-assembly regenerated silk fibroin nanofibers on the properties of electrospun materials.

    PubMed

    Zhao, Huijing; Ren, Xia; Zhang, Yi; Huang, Lei

    2015-01-01

    In this study, self-assembly regenerated silk fibroin (RSF) nanofibers were prepared and observed by Atomic Force Microscope (AFM). Then RSF films containing nanospheres and nanofibers were prepared and dissolved with poly (L-lactide-co-ε-caprolactone) (PLCL) with a blending ratio of 30/70 in hexafluoro-2-propanol (HFIP). In order to determine whether different nanostructures in the solution influence the morphological, structural, and mechanical properties of the final electrospun materials, flat membranes were prepared and characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FT-IR), and mechanical testing. The secondary structure of as-spun materials with RSF nanofibers were not changed, however, the diameter of electrospun fibers decreased and tensile strength and elongation at breaks increased. Electrospun materials with RSF nanofibers have the potential to be used for skin, cartilage, and blood vessels because of their biocompatibility and improved mechanical properties. PMID:26406088

  3. Influence of tragacanth gum in egg white based bioplastics: Thermomechanical and water uptake properties.

    PubMed

    López-Castejón, María Luisa; Bengoechea, Carlos; García-Morales, Moisés; Martínez, Inmaculada

    2016-11-01

    This study aims to extend the range of applications of tragacanth gum by studying its incorporation into bioplastics formulation, exploring the influence that different gum contents (0-20wt.%) exert over the thermomechanical and water uptake properties of bioplastics based on egg white albumen protein (EW). The effect of plasticizer nature was also evaluated through the modification of the water/glycerol ratio within the plasticizer fraction (fixed at 40wt.%). The addition of tragacanth gum generally yielded an enhancement of the water uptake capacity, being doubled at the highest content. Conversely, presence of tragacanth gum resulted in a considerable decrease in the bioplastic mechanical properties: both tensile strength and maximum elongation were reduced up to 75% approximately when compared to the gum-free system. Ageing of selected samples was also studied, revealing an important effect of storage time when tragacanth gum is present, possibly due to its hydrophilic character. PMID:27516250

  4. Influence of carbonyl iron particle coating with silica on the properties of magnetorheological elastomers

    NASA Astrophysics Data System (ADS)

    Małecki, P.; Królewicz, M.; Hiptmair, F.; Krzak, J.; Kaleta, J.; Major, Z.; Pigłowski, J.

    2016-10-01

    In this paper, the influence of encapsulating carbonyl iron particles with various silica coatings on the properties of magnetorheological elastomers (MREs) was investigated. A soft styrene-ethylene-butylene-styrene thermoplastic elastomer was used as the composite’s polymer matrix. Spherical carbonyl iron powder (CIP) acted as the ferromagnetic filler. In order to improve the metal-polymer interaction, carbonyl iron particles were coated with two types of single and six types of double silica layers. The first layer was created through a TMOS or TEOS hydrolysis whereas the second one was composed of organosilanes. The mechanical properties of MREs containing 38.5 vol% of CIP were analysed under dynamic loading conditions. To investigate the magnetorheological effect in these composites, a 430 mT magnetic field, generated by an array of permanent magnets, was applied during testing. The results revealed that the magnetomechanical response of the MREs differs substantially, depending on the kind of particle coating.

  5. Diphenylphosphino Styrene-Containing Homopolymers: Influence of Alkylation and Mobile Anions on Physical Properties.

    PubMed

    Jangu, Chainika; Schultz, Alison R; Wall, Candace E; Esker, Alan R; Long, Timothy E

    2016-07-01

    Conventional free radical polymerization and post-alkylation of 4-diphenylphosphino styrene (DPPS) generate a new class of high-molecular-weight phosphonium-containing homopolymers with tunable thermal, viscoelastic, and wetting properties. Post-alkylation and subsequent anion exchange provide an effective method for tuning Tg values and thermal stability as a function of alkyl chain length and counteranion selection (X(-) , BF4 (-) , TfO(-) , and Tf2 N(-) ). Rheological characterization facilitates the generation of time-temperature-superposition (TTS) pseudomaster curves and subsequent analysis of frequency sweeps at various temperatures reveals two relaxation modes corresponding to long-range segmental motion and the onset of viscous flow. Contact angle measurements reveal the influence of counteranion selection on wetting properties, revealing increased contact angles for homopolymers containing nucleophilic counteranions. These investigations provide fundamental insight into phosphonium-containing polymers, aiming to guide future research and applications involving electro-active polymeric devices.

  6. Influence of Heat Treatment Conditions on the Properties of Vanadium Oxide Thin Films for Thermochromic Applications.

    PubMed

    Kim, Donguk; Kwon, Samyoung; Park, Young; Boo, Jin-Hyo; Nam, Sang-Hun; Joo, Yang Tae; Kim, Minha; Lee, Jaehyeong

    2016-05-01

    In present work, the effects of the heat treatment on the structural, optical, and thermochromic properties of vanadium oxide films were investigated. Vanadium dioxide (VO2) thin films were deposited on glass substrate by reactive pulsed DC magnetron sputtering from a vanadium metal target in mixture atmosphere of argon and oxygen gas. Various heat treatment conditions were applied in order to evaluate their influence on the crystal phases formed, surface morphology, and optical properties. The films were characterized by an X-ray diffraction (XRD) in order to investigate the crystal structure and identify the phase change as post-annealing temperature of 500-600 degrees C for 5 minutes. Surface conditions of the obtained VO2(M) films were analyzed by field emission scanning electron microscopy (FE-SEM) and the semiconductor-metal transition (SMT) characteristics of the VO2 films were evaluate by optical spectrophotometry in the UV-VIS-NIR, controlling temperature of the films. PMID:27483853

  7. Investigations on the Mechanical Properties of Conducting Polymer Coating-Substrate Structures and Their Influencing Factors

    PubMed Central

    Wang, Xi-Shu; Tang, Hua-Ping; Li, Xu-Dong; Hua, Xin

    2009-01-01

    This review covers recent advances and work on the microstructure features, mechanical properties and cracking processes of conducting polymer film/coating- substrate structures under different testing conditions. An attempt is made to characterize and quantify the relationships between mechanical properties and microstructure features. In addition, the film cracking mechanism on the micro scale and some influencing factors that play a significant role in the service of the film-substrate structure are presented. These investigations cover the conducting polymer film/coating nucleation process, microstructure-fracture characterization, translation of brittle-ductile fractures, and cracking processes near the largest inherent macromolecule defects under thermal-mechanical loadings, and were carried out using in situ scanning electron microscopy (SEM) observations, as a novel method for evaluation of interface strength and critical failure stress. PMID:20054470

  8. Influence of various surfactants on magnetic property of cobalt ferrite prepared by Co-precipitation technique

    NASA Astrophysics Data System (ADS)

    Solanki, Neha; Khatri, Hemal; Jotania, R. B.

    2016-05-01

    Cobalt Ferrite (CoFe2O4) particles were synthesised using a Co-precipitation method. Influence of three different surfactants i.e. (1) Cationic - CTAB (Cetyl Tri-Methyl Ammonium Bromide), (2) Anionic - SDBS (Sodium Dodecyl Benzene Sulphonate) and (3) Nonionic - Triton X-100, on magnetic property of Cobalt Ferrite were investigated. Magnetic property of Cobalt ferrite powder was studied at room temperature using Vibrating Sample Measurements (VSM) technique under an applied magnetic field of 15kOe. The results show maximum value of saturation magnetization - Ms (81.87 emu/g) for the sample synthesised without surfactant and Coercivity value found maximum (2086 kOe) for the sample synthesized in presence of surfactant SDBS.

  9. Influence of hydroxyl content on selected properties of 45S5 bioactive glass.

    PubMed

    Hall, Matthew M

    2007-12-01

    Numerous material properties may be influenced by the concentration of chemically dissolved hydroxyl species within a glass. A tube furnace connected to a steam generator was used to create hydroxyl-saturated 45S5 glass under 1 atm of water at 1100 degrees C. Selected properties of as-melted and hydroxyl-saturated samples were compared to assess the sensitivity of 45S5 to excess hydroxylation. The glass transition temperature and the peak crystallization temperature of the treated 45S5 glass were reduced in comparison to the as-melted 45S5 glass. In addition, the treated glass exhibited a broad endothermic signal that may be indicative of enhanced viscous flow. A simple dissolution experiment indicated that the treated 45S5 glass was also less durable than the as-melted 45S5 glass. PMID:17559121

  10. How Far Does a Receptor Influence Vibrational Properties of an Odorant?

    PubMed Central

    Kongsted, Jacob; Solov’yov, Ilia A.

    2016-01-01

    The biophysical mechanism of the sense of smell, or olfaction, is still highly debated. The mainstream explanation argues for a shape-based recognition of odorant molecules by olfactory receptors, while recent investigations suggest the primary olfactory event to be triggered by a vibrationally-assisted electron transfer reaction. We consider this controversy by studying the influence of a receptor on the vibrational properties of an odorant in atomistic details as the coupling between electronic degrees of freedom of the receptor and the vibrations of the odorant is the key parameter of the vibrationally-assisted electron transfer. Through molecular dynamics simulations we elucidate the binding specificity of a receptor towards acetophenone odorant. The vibrational properties of acetophenone inside the receptor are then studied by the polarizable embedding density functional theory approach, allowing to quantify protein-odorant interactions. Finally, we judge whether the effects of the protein provide any indications towards the existing theories of olfaction. PMID:27014869

  11. Influence of cobalt, tantalum, and tungsten on the microstructure and mechanical properties of superalloy single crystals

    NASA Technical Reports Server (NTRS)

    Nathal, M. V.; Ebert, L. J.

    1982-01-01

    The influence of Co, Ta, and W on the microstructure and mechanical properties of nickel base super-alloy single crystals was investigated. A matrix of alloys was based on Mar-M 247 stripped of C, B, Zr, and Hf. The microstructures of the alloys were examined using optical and electron microscopy, phase extraction, X-ray diffraction, and differential thermal analysis. Tensile and creep-rupture tests were performed at 1000 C. An increase in tensile and creep strength resulted when Co was removed from alloys containing high refractory metal contents, but Co effects were negligible for alloys with lower refractory metal levels. In the composition range studied, W was more effective than Ta in increasing the creep resistance. The mechanical properties are discussed in relation to the microstructures of the alloys.

  12. Chemical force microscopy study of adhesive properties of polypropylene films: influence of surface polarity and medium.

    PubMed

    Gourianova, Svetlana; Willenbacher, Norbert; Kutschera, Michael

    2005-06-01

    The adhesive properties of untreated and corona treated polypropylene (PP) films were studied in polar (water) and nonpolar (hexadecane) liquid medium by using chemical force microscopy. A gold-coated colloidal probe was sequentially modified with self-assembled monolayers (SAMs) of omega-functionalized alkanethiols. The same colloidal probe was used for the force measurements, to avoid influence of determination accuracy of the spring constant and sphere radius on the obtained results. The thermodynamic work of adhesion was determined from the measured pull-off force using the Johnson-Kendall-Roberts (JKR) adhesion theory. Rabinovich's model was applied for the consideration of an effect of roughness when calculating the work of adhesion. It was found that the work of adhesion correlates with the hydrophilic properties of the PP surface and SAMs as well as with the polarity of the liquid medium. The observed correlations agree well with those found for the work of adhesion calculated from contact angle measurement.

  13. Optical properties of mice skin for optical therapy relevant wavelengths: influence of gender and pigmentation

    NASA Astrophysics Data System (ADS)

    Sabino, C. P.; Deana, A. M.; Silva, D. F. T.; França, C. M.; Yoshimura, T. M.; Ribeiro, M. S.

    2015-03-01

    Red and near-infrared light have been widely employed in optical therapies. Skin is the most common optical barrier in non-invasive techniques and in many cases it is the target tissue itself. Consequently, to optimize the outcomes brought by lightbased therapies, the optical properties of skin tissue must be very well elucidated. In the present study, we evaluated the dorsal skin optical properties of albino (BALB/c) and pigmented (C57BL/6) mice using the Kubelka-Munk photon transport model. We evaluated samples from male and female young mice of both strains. Analysis was performed for wavelengths at 630, 660, 780, 810 and 905 nm due to their prevalent use in optical therapies, such as low-level light (or laser) and photodynamic therapies. Spectrophotometric measurements of diffuse transmittance and reflectance were performed using a single integrating sphere coupled to a proper spectrophotometer. Statistic analysis was made by two-way ANOVA, with Tukey as post-test and Levenne and Shapiro-Wilks as pre-tests. Statistical significance was considered when p<0.05. Our results show only a slight transmittance increment (<10 %) as wavelengths are increased from 630 to 905 nm, and no statistical significance was observed. Albino male mice present reduced transmittance levels for all wavelengths. The organization and abundance of skin composing tissues significantly influence its scattering optical properties although absorption remains constant. We conclude that factors such as subcutaneous adiposity and connective tissue structure can have statistically significant influence on mice skin optical properties and these factors have relevant variations among different gender and strains.

  14. Influence of cooling rate on interlaminar fracture properties of unidirectional commingled CF/PEEK composites

    NASA Astrophysics Data System (ADS)

    Beehag, Andrew; Ye, Lin

    1995-05-01

    The influence of cooling rates on the mechanical property profile (transverse flexure properties and modes-I and -II interlaminar fracture toughness) has been investigated for unidirectional commingled CF/PEEK composites. A laboratory hot press with a steel mould was used to process the composites at 400°C for 60 min, at an applied pressure of 1 MPa. Cooling rates from fast (quenching in oil) to slow (hot press cooling) were achieved at ambient pressure. The results indicate that different matrix morphology was found at different cooling conditions, although deconsolidation occurred in the CF/PEEK composites during cooling. When the cooling rate was shifted from slow to fast, consolidation quality of the CF/PEEK composites was improved. The resulting effect of the consolidation quality and cooling rates on the mechanical property profile of commingled CF/PEEK composites is presented. It was found that the effect of the cooling rate on the mechanical property profile of the commingled CF/PEEK composites could not be isolated from the consolidation quality.

  15. Compound Microstructures and Wax Layer of Beetle Elytral Surfaces and Their Influence on Wetting Properties

    PubMed Central

    Sun, Mingxia; Liang, Aiping; Watson, Gregory S.; Watson, Jolanta A.; Zheng, Yongmei; Jiang, Lei

    2012-01-01

    A beetles’ first line of defense against environmental hazards is their mesothoracic elytra – rigid, protective forewings. In order to study the interaction of these wings with water, the surface microstructures of various beetles’ elytra were observed by Environment Scanning Electron Microscopy (ESEM) and Atomic Force Microscopy (AFM). Chemistry components were ascertained using X-ray photoelectron spectroscopy (XPS). All the beetles of various habitats (including desert, plant, dung, land and water) exhibited compound microstructures on their elytra. The wetting properties of these elytra were identified using an optical contact angle meter. In general the native elytra exhibited hydrophilic or weak hydrophobic properties with contact angles (CAs) ranging from 47.5° to 109.1°. After treatment with chloroform, the CAs all increased on the rougher elytral surfaces. The presence of wax is not the only determinant of hydrophobic properties, but rather a combination with microscopic structures found on the surfaces. Irregularities and the presence or absence of tiny cracks, hairs (or setae), pores and protrusions are important factors which influence the wetting properties. Rougher elytral surfaces tended to present a stronger hydrophobicity. Effects on hydrophobicity, such as surface microstructures, chemistry, environment and aging (referring to the time after emergence), are also included and discussed. Our results also provide insights into the motion of water droplets when in contact with beetle elytra. PMID:23056414

  16. Influence of soil properties on the bioaccumulation and effects of arsenic in the earthworm Eisenia andrei.

    PubMed

    Romero-Freire, A; Peinado, F J Martín; Ortiz, M Díez; van Gestel, C A M

    2015-10-01

    This study aimed at assessing the influence of soil properties on the uptake and toxicity effects of arsenic in the earthworm Eisenia andrei exposed for 4 weeks to seven natural soils spiked with different arsenic concentrations. Water-soluble soil concentrations (AsW) and internal As concentrations in the earthworms (AsE) were greatly different between soils. These two variables were highly correlated and were key factors in earthworm toxicity response. AsW was explained by some soil properties, such as the pH, calcium carbonate content, ionic strength, texture or oxide forms. Toxicity showed a clear variation between soils, in some cases without achieving 50 % adverse effect at the highest As concentration added (600 mg kg(-1)). Nevertheless, soil properties did not show, in general, a high relation with studied toxicity endpoints, although the high correlation with AsW could greatly reduce indirectly As bioavailability and toxicity risk for earthworms. Obtained results suggest that soil properties should be part of the criteria to establishing thresholds for contaminated soils because they will be key in controlling As availability and thus result in different degrees of toxicity. PMID:26002360

  17. Gum Tragacanth Fibers from Astragalus gummifer Species: Effects of Influencing Factors on Mechanical Properties of Fibers

    NASA Astrophysics Data System (ADS)

    Khajavi, Ramin; Mossavi Pourgharbi, Seyed Hossein; Kiumarsi, Amir; Rashidi, Abosayeed

    Gum Tragacanth (GT) is one of the most widely used natural gum across the globe and it is shown that GT from Asteragalus gummifer can be processed into fiber via alkaline treatment. In this study a complementary description of GT fibers is provided and the effects of influencing factors on properties of GT fibers investigated. Spinning Dope (SD) prepared by adding ribbon type GT of Astragalus gummifer species to alkaline solutions and fibers produced by solution spinning method. The effects of some processing factors including: draft ratio, residence time in coagulation bath, GT concentration in SD, ripening time of SD, kind of coagulant agent and the pH of washing bath on some mechanical properties of GT fibers studied. It was concluded that with increasing the coagulant concentration the mechanical properties of fibers improved, but it caused formation of sheet core structure. ZnCl2 as coagulant agent improved mechanical properties and applying glycerol caused more flexibility in GT fibers, even though their tenacity reduced.

  18. Influence of soil properties on the bioaccumulation and effects of arsenic in the earthworm Eisenia andrei.

    PubMed

    Romero-Freire, A; Peinado, F J Martín; Ortiz, M Díez; van Gestel, C A M

    2015-10-01

    This study aimed at assessing the influence of soil properties on the uptake and toxicity effects of arsenic in the earthworm Eisenia andrei exposed for 4 weeks to seven natural soils spiked with different arsenic concentrations. Water-soluble soil concentrations (AsW) and internal As concentrations in the earthworms (AsE) were greatly different between soils. These two variables were highly correlated and were key factors in earthworm toxicity response. AsW was explained by some soil properties, such as the pH, calcium carbonate content, ionic strength, texture or oxide forms. Toxicity showed a clear variation between soils, in some cases without achieving 50 % adverse effect at the highest As concentration added (600 mg kg(-1)). Nevertheless, soil properties did not show, in general, a high relation with studied toxicity endpoints, although the high correlation with AsW could greatly reduce indirectly As bioavailability and toxicity risk for earthworms. Obtained results suggest that soil properties should be part of the criteria to establishing thresholds for contaminated soils because they will be key in controlling As availability and thus result in different degrees of toxicity.

  19. Indexical properties influence time-varying amplitude and fundamental frequency contributions of vowels to sentence intelligibility

    PubMed Central

    Fogerty, Daniel

    2015-01-01

    The present study investigated how non-linguistic, indexical information about talker identity interacts with contributions to sentence intelligibility by the time-varying amplitude (temporal envelope) and fundamental frequency (F0). Young normal-hearing adults listened to sentences that preserved the original consonants but replaced the vowels with a single vowel production. This replacement vowel selectively preserved amplitude or F0 cues of the original vowel, but replaced cues to phonetic identity. Original vowel duration was always preserved. Three experiments investigated indexical contributions by replacing vowels with productions from the same or different talker, or by acoustically morphing the original vowel. These stimulus conditions investigated how vowel suprasegmental and indexical properties interact and contribute to intelligibility independently from phonetic information. Results demonstrated that indexical properties influence the relative contribution of suprasegmental properties to sentence intelligibility. F0 variations are particularly important in the presence of conflicting indexical information. Temporal envelope modulations significantly improve sentence intelligibility, but are enhanced when either indexical or F0 cues are available. These findings suggest that F0 and other indexical cues may facilitate perceptually grouping suprasegmental properties of vowels with the remainder of the sentence. Temporal envelope modulations of vowels may contribute to intelligibility once they are successfully integrated with the preserved signal. PMID:26543276

  20. Influence of interfacial properties and inhomogeneity on formation of microdamage in bone

    NASA Astrophysics Data System (ADS)

    Nakade, Rugved

    Microdamage accumulation at the nanoscopic level of bone affects the overall mechanical behavior of the bone. This makes it necessary to study the mechanisms through which microdamage accumulation can take place at the nanoscopic level. Experiments on bone's different hierarchy are difficult because of the small sizes of these hierarchical structures. Prevention of bone fractures is greatly enhanced with the help of predictive computational tools and hence used to evaluate the effects of microdamage in bone. There are two main types of microdamage that can form in the bone; linear cracks and diffuse damage. The bone nanostructure consists of mineral platelets embedded in soft protein called collagen and can be treated as a composite material. In this study, a two-dimensional probabilistic finite element model of the bone nanostructure was developed to evaluate the likely formation of the microdamage in the nanostructure due to changes in material properties of the nanostructure. The influence of the microdamage formation due to the collagen-mineral interface strength and also the effects of inhomogeneity were studied. To study interfacial strength effects, cohesive elements using bilinear traction separation laws were used to simulate the behavior of the interface (by way of interfacial debonding) between the collegen-mineral layers. Random field theory was used to assign spatially correlated random variables in order to assign inhomogeneous material properties to the bone. Correlation lengths were used to control the level of inhomogeneity in the model. The analysis showed that the type of microdamage was significantly influenced by the strength of the mineral-collagen interface. Probabilistic failure analyses indicated that strong interfaces resulted in limited interfacial debonding and narrow stress concentrations around an initial defect in the mineral-collagen composite, thereby suggesting that the likely location of failure was in same plane of the initial

  1. Bioacceptable and calcification-resistant membranes and interfaces for implantable sensors and devices

    NASA Astrophysics Data System (ADS)

    Galeska, Izabela Ewa

    The rational design and characterization of biocompatible, semipermeable and calcification resistant materials to serve as an outer membrane for implantable glucose biosensors, was the primary focus of this research. Multilayered films of polyanions (i.e. Nafion(TM), a perfluorinated ionomer, and Humic Acids (HAs), naturally occurring biopolymers), fabricated by layer-by-layer self-assembly with oppositely charged ferric ions were investigated as potential membranes. Spectroscopic ellipsometry and quartz crystal microbalance studies point towards a stepwise film growth, with growth rates of 47 and 24.3 nm per layer (for Nafion and HAs respectively) that can be altered depending on the pH and ionic strength of the polyanion solution. Nafion/Fe3+ assembled films exhibited an order of magnitude lower calcification as compared to dip-coated Nafion films and did not require annealing to impart insolubility. Similarly the HAs/Fe3+ films were also devoid of calcification, even after four-week immersion in DMEM cell culture media. Significantly, in vivo studies on the HAs/Fe3 films point to their biocompatibility as demonstrated by mild tissue reaction. These results, along with controllable glucose permeability, could prove vital in prolonging the lifetime of implantable biosensors. Additionally in effort to minimize tissue trauma upon implantation, novel poly(lactic-co-glycolic acid) (PLGA) microsphere/poly(vinyl alcohol) (PVA) hydrogel composites were investigated for dexamethasone delivery. A release rate of 25 to 40% over one month, following a zero order profile, was achieved by preferential adsorption of surface active polyacids (poly(acrylic acid), Nafion and HAs) on the hydrogel dispersed microspheres. Environmental scanning electron microscopy investigation on the degradation mechanism of the microspheres pointed towards their slow homogeneous degradation in the PVA hydrogels that was significantly surface-accelerated in the presence of polyacids. The physico

  2. Sensitivity of Calcification to Thermal Stress Varies among Genera of Massive Reef-Building Corals

    PubMed Central

    Carricart-Ganivet, Juan P.; Cabanillas-Terán, Nancy; Cruz-Ortega, Israel; Blanchon, Paul

    2012-01-01

    Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm−2 year−1 in Porites spp. and 0.12 g cm−2 year−1 in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ωar) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ωar changes on coral calcification rate in the MBR. Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown, seriously

  3. Spatial and seasonal reef calcification in corals and calcareous crusts in the central Red Sea

    NASA Astrophysics Data System (ADS)

    Roik, Anna; Roder, Cornelia; Röthig, Till; Voolstra, Christian R.

    2016-06-01

    The existence of coral reef ecosystems critically relies on the reef carbonate framework produced by scleractinian corals and calcareous crusts (i.e., crustose coralline algae). While the Red Sea harbors one of the longest connected reef systems in the world, detailed calcification data are only available from the northernmost part. To fill this knowledge gap, we measured in situ calcification rates of primary and secondary reef builders in the central Red Sea. We collected data on the major habitat-forming coral genera Porites, Acropora, and Pocillopora and also on calcareous crusts (CC) in a spatio-seasonal framework. The scope of the study comprised sheltered and exposed sites of three reefs along a cross-shelf gradient and over four seasons of the year. Calcification of all coral genera was consistent across the shelf and highest in spring. In addition, Pocillopora showed increased calcification at exposed reef sites. In contrast, CC calcification increased from nearshore, sheltered to offshore, exposed reef sites, but also varied over seasons. Comparing our data to other reef locations, calcification in the Red Sea was in the range of data collected from reefs in the Caribbean and Indo-Pacific; however, Acropora calcification estimates were at the lower end of worldwide rates. Our study shows that the increasing coral cover from nearshore to offshore environments aligned with CC calcification but not coral calcification, highlighting the potentially important role of CC in structuring reef cover and habitats. While coral calcification maxima have been typically observed during summer in many reef locations worldwide, calcification maxima during spring in the central Red Sea indicate that summer temperatures exceed the optima of reef calcifiers in this region. This study provides a foundation for comparative efforts and sets a baseline to quantify impact of future environmental change in the central Red Sea.

  4. Impact of seawater carbonate chemistry on the calcification of marine bivalves

    NASA Astrophysics Data System (ADS)

    Thomsen, J.; Haynert, K.; Wegner, K. M.; Melzner, F.

    2015-07-01

    Bivalve calcification, particularly of the early larval stages, is highly sensitive to the change in ocean carbonate chemistry resulting from atmospheric CO2 uptake. Earlier studies suggested that declining seawater [CO32-] and thereby lowered carbonate saturation affect shell production. However, disturbances of physiological processes such as acid-base regulation by adverse seawater pCO2 and pH can affect calcification in a secondary fashion. In order to determine the exact carbonate system component by which growth and calcification are affected it is necessary to utilize more complex carbonate chemistry manipulations. As single factors, pCO2 had no effects and [HCO3-] and pH had only limited effects on shell growth, while lowered [CO32-] strongly impacted calcification. Dissolved inorganic carbon (CT) limiting conditions led to strong reductions in calcification, despite high [CO32-], indicating that [HCO3-] rather than [CO32-] is the inorganic carbon source utilized for calcification by mytilid mussels. However, as the ratio [HCO3-] / [H+] is linearly correlated with [CO32-] it is not possible to differentiate between these under natural seawater conditions. An equivalent of about 80 μmol kg-1 [CO32-] is required to saturate inorganic carbon supply for calcification in bivalves. Below this threshold biomineralization rates rapidly decline. A comparison of literature data available for larvae and juvenile mussels and oysters originating from habitats differing substantially with respect to prevailing carbonate chemistry conditions revealed similar response curves. This suggests that the mechanisms which determine sensitivity of calcification in this group are highly conserved. The higher sensitivity of larval calcification seems to primarily result from the much higher relative calcification rates in early life stages. In order to reveal and understand the mechanisms that limit or facilitate adaptation to future ocean acidification, it is necessary to better

  5. Autophagy protects end plate chondrocytes from intermittent cyclic mechanical tension induced calcification.

    PubMed

    Xu, Hong-guang; Yu, Yun-fei; Zheng, Quan; Zhang, Wei; Wang, Chuang-dong; Zhao, Xiao-yn; Tong, Wen-xue; Wang, Hong; Liu, Ping; Zhang, Xiao-ling

    2014-09-01

    Calcification of end plate chondrocytes is a major cause of intervertebral disc (IVD) degeneration. However, the underlying molecular mechanism of end plate chondrocyte calcification is still unclear. The aim of this study was to clarify whether autophagy in end plate chondrocytes could protect the calcification of end plate chondrocytes. Previous studies showed that intermittent cyclic mechanical tension (ICMT) contributes to the calcification of end plate chondrocytes in vitro. While autophagy serves as a cell survival mechanism, the relationship of autophagy and induced end plate chondrocyte calcification by mechanical tension in vitro is unknown. Thus, we investigated autophagy, the expression of the autophagy genes, Beclin-1 and LC3, and rat end plate chondrocyte calcification by ICMT. The viability of end plate chondrocytes was examined using the LIVE/DEAD viability/cytotoxicity kit. The reverse transcription-polymerase chain reaction and western blotting were used to detect the expression of Beclin-1; LC3; type I, II and X collagen; aggrecan; and Sox-9 genes. Immunofluorescent and fluorescent microscopy showed decreased autophagy in the 10- and 20-day groups loaded with ICMT. Additionally, Alizarin red and alkaline phosphatase staining detected the palpable calcification of end plate chondrocytes after ICMT treatment. We found that increased autophagy induced by short-term ICMT treatment was accompanied by an insignificant calcification of end plate chondrocytes. To the contrary, the suppressive autophagy inhibited by long-term ICMT was accompanied by a more significant calcification. The process of calcification induced by ICMT was partially resisted by increased autophagy activity induced by rapamycin, implicating that autophagy may prevent end plate chondrocyte calcification.

  6. Sensitivity of calcification to thermal stress varies among genera of massive reef-building corals.

    PubMed

    Carricart-Ganivet, Juan P; Cabanillas-Terán, Nancy; Cruz-Ortega, Israel; Blanchon, Paul

    2012-01-01

    Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm(-2) year(-1) in Porites spp. and 0.12 g cm(-2) year(-1) in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ω(ar)) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ω(ar) changes on coral calcification rate in the MBR. Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown

  7. Effects of Hydrogen Peroxide on Coral Photosynthesis and Calcification

    NASA Astrophysics Data System (ADS)

    Higuchi, T.; Fujimura, H.; Arakaki, T.; Oomori, T.

    2007-12-01

    The widely-observed decline of coral reefs is considered to be caused by changes in the environment by natural and anthropogenic activities. As one important factor, the run-off of various matters from human activities to the coastal seawater poses stresses to the corals by degrading the quality of the seawater. In Okinawa, Japan, red- soil running off from the developed land has been a major environmental issue since 1980s. Hydrogen peroxide (HOOH), a strong active oxygen species, is one of the photochemically formed chemicals in the red-soil-polluted seawater. Recent photochemical studies of seawater showed that HOOH photo-formation was faster in the red- soil-polluted seawater than clean seawater. We studied the effects of HOOH on corals by studying the changes in coral carbon metabolisms such as photosynthesis and calcification, which are indicators of the physiological state of a coral colony. The corals were exposed to various concentrations of HOOH (0, 0.3, 3 μM). Two massive coral species of Porites sp. and Goniastrea aspera and one branch coral of Galaxea facicularis were used for the exposure experiments. The control experiments showed that when no HOOH was added, metabolisms of each coral colony were relatively stable. On the other hand, when HOOH was added to the seawater, we observed obvious changes in the coral metabolisms in all the coral species. When 0.3 μM HOOH was added, photosynthesis decreased by 14% and calcification decreased by 17% within 3 days, compared with the control. When 3 μM HOOH was added, photosynthesis decreased by 21% and calcification decreased by 41% within 3 days, compared with the control. Our study showed that higher concentrations of HOOH posed more stress to the coral colonies.

  8. The influence of surface properties on uptake of oil into complex coacervate microcapsules.

    PubMed

    Rabiskova, M; Song, J; Opawale, F O; Burgess, D J

    1994-08-01

    A range of surfactants with different hydrophile-lipophile balance (HLB) values was selected to investigate the influence of interfacial properties on the uptake of oil droplets into complex coacervate microcapsules. The well characterized gelatin/acacia complex coacervate system was used in this study and the encapsulation of squalane, and oleic acid was investigated. The surfactants investigated were Span 85, Span 80, Span 40, egg yolk lecithin, and Tween 80. Combinations of surfactants were utilized to obtain intermediate HLB values. The percentage oil encapsulated was determined gravimetrically, based on the initial concentration and the amount extracted from the microcapsules. The aqueous interfacial tension values of the oils and oil/surfactant systems were measured using the Wilhelmy plate method. The interfacial properties were correlated to the percentage oil uptake by the coacervate phase. The relative hydrophobicity/lipophilicity of the oil influenced its uptake by complex coacervate droplets. The presence of surfactant affected oil uptake, depending on the HLB value of the surfactant or surfactant mixture. Uptake of squalane by the gelatin/acacia coacervates was found to be optimized by the addition of surfactants with HLB values in the range 2.5-6. The percentage uptake of oil decreased rapidly for systems prepared containing surfactants with HLB values outside this range. No correlation was observed between oil uptake by the coacervate phase and the interfacial tension of the oil and oil/surfactant systems with double-distilled deionized water.

  9. Influence of process variables on essential oil microcapsule properties by carbohydrate polymer-protein blends.

    PubMed

    Banerjee, Subham; Chattopadhyay, Pronobesh; Ghosh, Animesh; Goyary, Danswrang; Karmakar, Sanjeev; Veer, Vijay

    2013-04-01

    Carbohydrate polymer-protein blends Zanthoxylum limonella oil (ZLO) loaded microcapsules were prepared by multiple emulsion solvent evaporation technology and the influence of various processing variables on the properties of ZLO loaded microcapsules were examined systematically. It was found that the internal aqueous alginate phase volume, external aqueous gelatin phase volume and concentration of surfactant in external aqueous gelatin phase have a significant influence on microcapsules properties. The essential oil-loaded microcapsules were smooth and spherical in shape as revealed by scanning electron micrograph. Results of Fourier transform infrared (FTIR) spectroscopy indicated stable character and showed the absence of chemical interaction between the microencapsulated oil and carbohydrate polymer-protein blends. Differential scanning calorimetry (DSC) study revealed the antioxidant nature of ZLO in the microcapsules. The release rate of ZLO loaded microcapsules was analyzed by UV-vis spectrophotometer. 83.80% of oil encapsulation efficiency was obtained depending upon the processing variables. Thus, proper control of the processing variables involved in this technology could allow effective incorporation of essential oil into the core of the carbohydrate polymer-protein blends matrix.

  10. Influence of Fluorination on the Conformational Properties and Hydrogen-Bond Acidity of Benzyl Alcohol Derivatives

    PubMed Central

    Bogdan, Elena; Compain, Guillaume; Mtashobya, Lewis; Le Questel, Jean-Yves; Besseau, François; Galland, Nicolas; Linclau, Bruno; Graton, Jérôme

    2015-01-01

    The effect of fluorination on the conformational and hydrogen-bond (HB)-donating properties of a series of benzyl alcohols has been investigated experimentally by IR spectroscopy and theoretically with quantum chemical methods (ab initio (MP2) and DFT (MPWB1K)). It was found that o-fluorination generally resulted in an increase in the HB acidity of the hydroxyl group, whereas a decrease was observed upon o,o′-difluorination. Computational analysis showed that the conformational landscapes of the title compounds are strongly influenced by the presence of o-fluorine atoms. Intramolecular interaction descriptors based on AIM, NCI and NBO analyses reveal that, in addition to an intramolecular OH⋅⋅⋅F interaction, secondary CH⋅⋅⋅F and/or CH⋅⋅⋅O interactions also occur, contributing to the stabilisation of the various conformations, and influencing the overall HB properties of the alcohol group. The benzyl alcohol HB-donating capacity trends are properly described by an electrostatic potential based descriptor calculated at the MPWB1K/6-31+G(d,p) level of theory, provided solvation effects are taken into account for these flexible HB donors. PMID:26130594

  11. Influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules.

    PubMed

    Song, Zhiwei; Li, Ting; Wang, Qiuxu; Pan, Yu; Li, Lixin

    2015-09-01

    In order to evaluate the influence of microbial community structure of seed sludge on the properties of aerobic nitrifying granules, these granules were cultivated with different seed sludge, and the variation of microbial community and dominant bacterial groups that impact the nitrogen removal efficiency of the aerobic nitrifying granules were analyzed and identified using 16s rDNA sequence and denaturing gradient gel electrophoresis (DGGE) profiles. The results presented here demonstrated that the influence of the community structure of seed sludge on the properties of aerobic nitrifying granules was remarkable, and the granules cultivated by activated sludge from a beer wastewater treatment plant showed better performance, with a stable sludge volume index (SVI) value of 20mL/g, high extracellular polymeric substance (EPS) content of 183.3mg/L, high NH4(+)-N removal rate of 89.42% and abundant microbial population with 10 dominant bacterial groups. This indicated that activated sludge with abundant communities is suitable for use as seed sludge in culturing aerobic nitrifying granules. PMID:26354703

  12. The influence of substrate temperature on the tribo- mechanical properties of chromium nitride thin films

    NASA Astrophysics Data System (ADS)

    Merie, V. V.; Negrea, G.; Modi, E.

    2016-08-01

    Different nitrides such as titanium nitride, chromium nitride and so on are used in a widespread range of applications such as cutting tools, medical implants, and microelectromechanical devices and all that due to their mechanical, physical and chemical properties. The aim of this study is to obtain chromium nitride thin films and to characterize them by atomic force microscopy investigations. The chromium nitride thin films were deposited by reactive magnetron sputtering on silicon substrates. During the deposition process, the discharge current, the argon and nitrogen flows, the pressure inside the chamber and the deposition time were kept constant. A chromium target with a purity of 99.95 % was used. Some of the films were deposited after a chromium buffer layer was previously deposited on the silicon substrate. The deposition was carried out when substrate temperature was at room temperature, at 300 and 500°C respectively. Once the films were deposited, atomic force microscopy investigations were performed in order to emphasize the influence of the substrate temperature on the topographical, mechanical and tribological characteristics. The results pointed out an important influence of the substrate temperature on topographical, mechanical and tribological properties of the investigated chromium nitride thin films.

  13. Influence of soil properties on copper toxicity for two soil invertebrates.

    PubMed

    Criel, Peggy; Lock, Koen; Eeckhout, Hilde Van; Oorts, Koen; Smolders, Erik; Janssen, Colin R

    2008-08-01

    Although a large body of evidence indicates that metal toxicity to soil organisms is affected by physicochemical soil properties, use of this knowledge in ecological risk assessments is limited because of the lack of a model applicable to a wide range of soils. To study the effect of soil characteristics on the toxicity of copper to terrestrial invertebrates, chronic toxicity tests with Eisenia fetida and Folsomia candida were performed in 19 European field soils. These soils were carefully selected to cover the range of toxicity-influencing parameters encountered in the European Union. Toxicity values varied greatly among soils, with 28-d median effect concentrations ranging from 72.0 to 781 mg Cu/kg dry weight for E. fetida and from 45.4 to 2,270 mg Cu/kg dry weight for F. candida. For both species, variation in copper toxicity values was best explained by differences in the actual cation-exchange capacity (CEC) at soil pH. Using the obtained regression algorithms, the observed toxicity could, in most cases, be predicted within a factor of two for E. fetida and within a factor of three for F. candida. The developed models were validated in three additional European field soils, a standard artificial soil and a standard field soil. The presented regression equations, based on the actual CEC, offer an easy-to-apply method for taking the influence of soil properties on metal toxicity into account.

  14. How contamination sources and soil properties can influence the Cd and Pb bioavailability to snails.

    PubMed

    Pauget, Benjamin; Gimbert, Frédéric; Coeurdassier, Mickael; Druart, Coline; Crini, Nadia; de Vaufleury, Annette

    2016-02-01

    To better understand the fate of metals in the environment, numerous parameters must be studied, such as the soil properties and the different sources of contamination for the organisms. Among bioindicators of soil quality, the garden snail (Cantareus aspersus) integrates multiple sources (e.g. soil, plant) and routes (e.g. digestive, cutaneous) of contamination. However, the contribution of each source on metal bioavailability and how soil properties influence these contributions have never been studied when considering the dynamic process of bioavailability. Using accumulation kinetics, this study showed that the main assimilation source of Cd was lettuce (68%), whereas the main source of Pb was the soil (90%). The plant contribution increased in response to a 2-unit soil pH decrease. Unexpectedly, an increase in the soil contribution to metal assimilation accompanied an increase in the organic matter (OM) content of the soil. For both metals, no significant excretion and influence of source on excretion have been modelled either during exposure or depuration. This study highlights how the contribution of different sources to metal bioavailability changes based on changes in soil parameters, such as pH and OM, and the complexity of the processes that modulate metal bioavailability.

  15. Influences of sediment properties and macrophytes on phosphorous speciation in the intertidal marsh.

    PubMed

    Shao, Xuexin; Liang, Xinqiang; Wu, Ming; Gu, Binhe; Li, Wenhua; Sheng, Xuancai; Wang, Shaoxian

    2014-09-01

    Phosphorus (P) in wetlands is mainly bound to sediment in various species, which is essential to predict water column P levels. The purpose of this work is to understand the influences of sediment properties and vegetation types on P speciation. Sediments under four vegetation types in the tidal flat and offshore sandbar in Hangzhou Bay of China were collected seasonally. The rank order of P species in sediment based on concentration was exchangeable P (Exch-P) < iron/aluminum-bound P (Fe/Al-P) < organic P (Org-P) < calcium-bound P (Ca-P). Sediment total phosphorus (TP) and Fe/Al-P concentrations were lower in offshore sandbar than those of tidal flat, reflecting effects of anthropogenic contamination in the latter. Sediment particle size distribution strongly affected P speciation, as indicated by a significant correlation between them. Total phosphorus and Org-P concentrations in vegetated sediments were higher than those of bare mudflat. Additionally, there was a significant negative correlation between Ca-P and Org-P, and Fe/Al-P, indicating the presence of vegetation which may result in P speciation by converting Ca-P to soluble and active P and higher Org-P. Overall, sediment particle size distribution is the most fundamental physical property that affects P speciation, and vegetation types are important factors that influence Org-P concentration.

  16. Influence of semi-volatile aerosol on physical and optical properties of aerosol in Kathmandu valley

    NASA Astrophysics Data System (ADS)

    Shrestha, Sujan; Praveen, Ps; Adhikary, Bhupesh; Shrestha, Kundan; Panday, Arnico

    2016-04-01

    A field study was conducted in the urban atmosphere of Kathmandu valley to study the influence of the semi-volatile aerosol fraction on physical and optical properties of aerosols. The study was carried out during the 2015 pre-monsoon period. Experimental setup consisted of air from an ambient air inlet being split to two sets of identical sampling instruments. The first instrument received the ambient sample directly, while the second instrument received the air sample through a thermodenuder (TDD). Four sets of experiments were conducted to understand aerosol number, size distribution, scattering and absorption properties using Condensation Particle Counter (CPC), Scanning Mobility Particle Sizer (SMPS), Aethalometer (AE33) and Nephelometer. The influence of semi-volatile aerosols was calculated from the fraction of particles evaporated in the TDD at set temparetures: room temperature, 50°C, 100°C, 150°C, 200°C, 250°C and 300°C. Results show that, with increasing temperature, the evaporated fraction of semi-volatile aerosol also increased. At room temperature the fraction of semi-volatile aerosols was 12% while at 300°C it was as high as to 49%. Aerosol size distribution analysis shows that with an increase in TDD temperature from 50°C to 300°C, peak mobility diameter of particles shifted from around 60nm to 40nm. However we found little change in effective diameter of aerosol size distribution with increase in set TDD temperature. The change in size of aerosols due to loss of semi-volatile component has a stronger influence (~70%) in higher size bins when compared to at lower size bins (~20%). Studies using the AE33 showed that absorption by black carbon (BC) is amplified due to influence of semi-volatile aerosols by upto 37% at 880nm wavelength. Similarly nephelometer measurements showed that upto 71% of total scattering was found to be contributed by semi-volatile aerosol fraction. The scattering Angstrom Exponent (SAE) of semi-volatile aerosol

  17. [Brain calcifications: a case presentation of congenital toxoplasmosis].

    PubMed

    Ávila, Mauricio J; Rodríguez-Restrepo, Andrea

    2014-12-18

    Toxoplasmosis is a common disease in Latin America. The infection has a major impact on public health worldwide. Congenital toxoplasmosis is part of the spectrum of the disease and the consequences for the newborn are devastating. In this article, we present a case of brain calcifications and hydrocephalus secondary to infection with Toxoplasma gondii in a newborn, as well as the outcome during follow-up and long-term sequelae. It is of high importance for the clinician to think about this disease, due to its high prevalence in Latin America, and to adopt adequate measures for its prevention and timely management in order to reduce long-term sequelae.

  18. Influence of temperature-dependent material properties on heat transfer in the turbulent flow over a flat plate

    NASA Astrophysics Data System (ADS)

    Wehle, F.; Brandt, F.

    The influence of temperature dependence of material properties on heat transfer in a turbulent plate boundary layer is investigated using differential equations for the velocity and temperature fields of even, steady, and compressible boundary layer flows. The results are compared with the well-known material property correction factors of Zhukauskas (1966), Sieder and Tate (1936), and Hufschmidt and Bruck (1968).

  19. Influence of inhomogeneous damping distribution on sound radiation properties of complex vibration modes in rectangular plates

    NASA Astrophysics Data System (ADS)

    Unruh, Oliver

    2016-09-01

    In order to reduce noise emitted by vibrating structures additional damping treatments such as constraint layer damping or embedded elastomer layers can be used. To save weight and cost, the additional damping is often placed at some critical locations of the structure, what leads to spatially inhomogeneous distribution of damping. This inhomogeneous distribution of structural damping leads to an occurrence of complex vibration modes, which are no longer dominated by pure standing waves, but by a superposition of travelling and standing waves. The existence of complex vibration modes raises the question about their influence on sound radiation. Previous studies on the sound radiation of complex modes of rectangular plates reveal, that, depending on the direction of travelling waves, the radiation efficiency of structural modes can slightly decrease or significantly increase. These observations have been made using a rectangular plate with a simple inhomogeneous damping configuration which includes a single plate boundary with a higher structural damping ratio. In order to answer the question about the influence of other possible damping configurations on the sound radiation properties, this paper addresses the self- and mutual-radiation efficiencies of the resulting complex vibration modes. Numerical simulations are used for the calculation of complex structural modes of different inhomogeneous damping configurations with varying geometrical form and symmetry. The evaluation of self- and mutual-radiation efficiencies reveals that primarily the symmetry properties of the inhomogeneous damping distribution affect the sound radiation characteristics. Especially the asymmetric distributions of inhomogeneous damping show a high influence on the investigated acoustic metrics. The presented study also reveals that the acoustic cross-coupling between structural modes, which is described by the mutual-radiation efficiencies, generally increases with the presence of

  20. Influence of fermentation conditions on the surface properties and adhesion of Lactobacillus rhamnosus GG

    PubMed Central

    2012-01-01

    Background The surface properties of probiotic bacteria influence to a large extent their interactions within the gut ecosystem. There is limited amount of information on the effect of the production process on the surface properties of probiotic lactobacilli in relation to the mechanisms of their adhesion to the gastrointestinal mucosa. The aim of this work was to investigate the effect of the fermentation pH and temperature on the surface properties and adhesion ability to Caco-2 cells of the probiotic strain Lactobacillus rhamnosus GG. Results The cells were grown at pH 5, 5.5, 6 (temperature 37°C) and at pH 6.5 (temperature 25°C, 30°C and 37°C), and their surfaces analysed by X-ray photoelectron spectrometry (XPS), Fourier transform infrared spectroscopy (FT-IR) and gel-based proteomics. The results indicated that for all the fermentation conditions, with the exception of pH 5, a higher nitrogen to carbon ratio and a lower phosphate content was observed at the surface of the bacteria, which resulted in a lower surface hydrophobicity and reduced adhesion levels to Caco-2 cells as compared to the control fermentation (pH 6.5, 37°C). A number of adhesive proteins, which have been suggested in previous published works to take part in the adhesion of bacteria to the human gastrointestinal tract, were identified by proteomic analysis, with no significant differences between samples however. Conclusions The temperature and the pH of the fermentation influenced the surface composition, hydrophobicity and the levels of adhesion of L. rhamnosus GG to Caco-2 cells. It was deduced from the data that a protein rich surface reduced the adhesion ability of the cells. PMID:22931558