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Sample records for properties influence calcification

  1. Substrate Properties Influence Calcification in Valvular Interstitial Cell Culture

    PubMed Central

    Benton, Julie A.; Kern, Hanna B.; Anseth, Kristi S.

    2009-01-01

    Background and aim of the study Valvular calcification is an active, cell-mediated process and results in significant morbidity and mortality. In standard culture, valvular interstitial cells (VICs) elicit significant calcification as a result of myofibroblast activation, and this limits the utility of these models to characterize VICs. In the work presented herein, we sought to investigate culturing substrates that suppress atypical VIC calcification and investigate culture substrates that represent a more physiological system. Methods Several culture platforms were selected to compare and contrast the influence of biochemical and mechanical properties on VIC calcification. Substrates investigated include: tissue culture polystyrene (TCPS), TCPS coated with either fibronectin or fibrin, and an elastic poly (ethylene glycol) (PEG) hydrogel with the same proteins coupled to the surface. Experiments were repeated with pro-fibrotic growth factor transforming growth factor- beta 1 (TGF-β1). VIC calcification was characterized by calcific nodule formation, alkaline phosphatase activity, and calcium accumulation. Gene and protein expression of alpha smooth muscle actin (αSMA) and core binding factor-1 (CBFa-1) were analyzed with qRT-PCR and immunostaining. Results Unmodified TCPS substrates had an innate ability to promote the markers of calcification studied. The addition of TGF-β1 enhanced all the levels of all osteoblastic markers studied. When TCPS surfaces were modified with fibronectin, all markers for calcification were repressed. However αSMA, a marker for myofibroblastic activity, was unchanged. Meanwhile fibrin modified TCPS surfaces enhanced calcification over unmodified TCPS substrates. On the soft PEG hydrogels, all markers for calcification were repressed regardless of the surface chemistry, while αSMA expression remained unaffected. Conclusions Collectively, VIC properties are highly linked to the culture microenvironment. Both the biochemical and

  2. Substrate properties influence calcification in valvular interstitial cell culture.

    PubMed

    Benton, Julie A; Kern, Hanna B; Anseth, Kristi S

    2008-11-01

    Valvular calcification is an active, cell-mediated process that results in significant morbidity and mortality. In standard culture, valvular interstitial cells (VICs) elicit significant calcification as a result of myofibroblast activation, and this limits their use in characterization studies. The study aim was to identify culturing substrates that would suppress atypical VIC calcification, and to investigate culture substrates representing a more physiological system. Several culture platforms were selected to compare and contrast the influence of biochemical and mechanical properties on VIC calcification. Substrates investigated included: tissue culture polystyrene (TCPS), TCPS coated with either fibronectin or fibrin, and an elastic poly(ethylene glycol) (PEG) hydrogel, also with fibronectin or fibrin coupled to the surface. Experiments were repeated with profibrotic growth factor transforming growth factor-beta 1 (TGF-beta1). VIC calcification was characterized by calcific nodule formation, alkaline phosphatase activity and calcium accumulation. Gene and protein expression of alpha smooth muscle actin (aSMA) and core binding factor-1 (CBFa-1) were analyzed with qRT-PCR and immunostaining. Unmodified TCPS substrates had an innate ability to promote the markers of calcification studied. The addition of TGF-beta1 enhanced levels of all osteoblastic markers studied. When TCPS surfaces were modified with fibronectin, all markers for calcification were repressed, but alphaSMA - a marker for myofibroblastic activity was unchanged. Meanwhile, fibrin-modified TCPS surfaces enhanced calcification over unmodified TCPS substrates. On soft PEG hydrogels, all markers for calcification were repressed, regardless of the surface chemistry, while alphaSMA expression remained unaffected. Collectively, VIC properties are highly linked to the culture microenvironment. Both, the biochemical and mechanical environment of tissue culture has an effect on the spontaneous calcification

  3. 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.

  4. 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.

  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

    2013-04-07

    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. Fixation of vascular grafts with increased glutaraldehyde concentration enhances mechanical properties without increasing calcification.

    PubMed

    Sánchez, Diana M; Gaitán, Diana M; León, Andrés F; Mugnier, Jacqueline; Briceño, Juan C

    2007-01-01

    Our objective was to study the effect of glutaraldehyde (GLU) concentration, heat, and photooxidation on mechanical properties and calcification of bovine pericardium grafts in an in vivo model. Fresh pericardia were treated as follows: 0.625% GLU for 7 days (standard); 0.625%, 1%, and 3% GLU at 4 degrees C for 20 days and 50 degrees C for additional 20 days; irradiation in cross-linking medium with metilene blue at 0 degrees C for 8 hours. Tissues were subjected to tensile mechanical tests (n = 76). Fixed patches were subcutaneously implanted in mice for 50 days (n = 16 per treatment). Calcification was assessed by atomic absorption spectrophotometry (n = 55) and von Kossa staining (n = 28). Analysis of variance and Tukey's test were used for statistical analysis. The 3% GLU and 3% GLU + heat treatments showed an enhancement of the mechanical properties above standard treatment. No significant difference was found in calcification between treatments. The 3% GLU treatment enhances the mechanical properties of the tissue above standard treatment without increasing calcification and without applying heat; therefore it is recommended for high-strength applications. Supplementary treatments to decrease calcification could be combined with this methodology to obtain a high-strength-low-calcification biomaterial for manufacturing of long-term cardiovascular grafts.

  8. Influence of aortic valve leaflet calcification on dynamic aortic valve motion assessed by cardiac computed tomography.

    PubMed

    Minami, Keisuke; Yoneyama, Kihei; Izumo, Masaki; Suzuki, Kengo; Ogawa, Yasuyoshi; Chikaraishi, Kousuke; Ogawa, Yukihisa; Kobayashi, Yasuyuki; Furukawa, Toshiyuki; Tanabe, Yasuhiro; Akashi, Yoshihiro J

    Computed tomography is the best noninvasive imaging modality for evaluating valve leaflet calcification. To evaluate the association of aortic valve leaflet calcification with instantaneous valve opening and closing using dynamic multidetector computed tomography (MDCT). We retrospectively evaluated 58 consecutive patients who underwent dynamic MDCT imaging. Aortic valve calcification (AVC) was quantified using the Agatston method. The aortic valve area (AVA) tracking curves were derived by planimetry during the cardiac cycle using all 20 phases (5% reconstruction). da/dt in cm(2)/s was calculated as the rate of change of AVA during opening (positive) or closing (negative). Patients were divided into 3 three groups according to Agatston score quartile: no AVC (Q2, Score 0, n = 18), mild AVC (Q3, Score 1-2254, n = 24), and severe AVC (Q4 Score >2254, n = 14). In multivariable linear regression, compared to the non AVC group, the mild and severe AVC groups had lower maximum AVA (by -1.71 cm(2) and -2.25 cm(2), respectively), lower peak positive da/dt (by -21.88 cm(2)/s and -26.65 cm(2)/s, respectively), and higher peak negative da/dt (by 13.78 cm(2)/s and 18.11 cm(2)/s, respectively) (p < 0.05 for all comparisons). AVA and its opening and closing were influenced by leaflet calcification. The present study demonstrates the ability of dynamic MDCT imaging to assess quantitative aortic valve motion in a clinical setting. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  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. 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

  11. On the influence of wall calcification and intraluminal thrombus on prediction of abdominal aortic aneurysm rupture.

    PubMed

    Barrett, Hilary E; Cunnane, Eoghan M; Hidayat, Hena; O'Brien, Julie M; Moloney, Michael A; Kavanagh, Eamon G; Walsh, Michael T

    2017-09-09

    Parameters other than maximum diameter that predict rupture of abdominal aortic aneurysms (AAAs) may be helpful for risk-benefit analysis in individual patients. The aim of this study was to characterize the biomechanical-structural characteristics associated with AAA walls to better identify the related mechanistic variables required for an accurate prediction of rupture risk. Anterior AAA wall (n = 40) and intraluminal thrombus (ILT; n = 114) samples were acquired from 18 patients undergoing open surgical repair. Biomechanical characterization was performed using controlled circumferential stretching tests combined with a speckle-strain tracking technique to quantify the spatial heterogeneity in deformation and localized strains in the AAA walls containing calcification. After mechanical testing, the accompanying microstructural characteristics of the AAA wall and ILT types were examined using electron microscopy. No significant correlation was found between the AAA diameter and the wall mechanical properties in terms of Cauchy stress (rs = -0.139; P = .596) or stiffness (rs = -0.451; P = .069). Quantification of significant localized peak strains, which were concentrated in the tissue regions surrounding calcification, reveals that peak strains increased by a mean of 174% as a result of calcification and corresponding peak stresses by 18.2%. Four ILT types characteristic of diverse stages in the evolving tissue microstructure were directly associated with distinct mechanical stiffness properties of the ILT and underlying AAA wall. ILT types were independent of geometric factors, including ILT volume and AAA diameter measures (ILT stiffness and AAA diameter [rs = -0.511; P = .074]; ILT stiffness and ILT volume [rs = -0.245; P = .467]). AAA wall stiffness properties are controlled by the load-bearing capacity of the noncalcified tissue portion, and low stiffness properties represent a highly degraded vulnerable wall. The presence of calcification

  12. Calcification rate influence on trace element concentrations in aragonitic bivalve shells: Evidences and mechanisms

    NASA Astrophysics Data System (ADS)

    Carré, Matthieu; Bentaleb, Ilhem; Bruguier, Olivier; Ordinola, Elmer; Barrett, Nicholas T.; Fontugne, Michel

    2006-10-01

    Trace elements in calcareous organisms have been widely used for paleoclimatic studies. However, the factors controlling their incorporation into mollusc shells are still unclear. We studied here the Sr, Mg, Ba and Mn serial records in the shells of two aragonitic marine bivalve species: Mesodesma donacium and Chione subrugosa from the Peruvian Coast. The elemental concentrations were compared to local temperature and salinity records. The relationships with crystal growth rate G were investigated thanks to well defined periodic growth structures providing a precise shell chronology. Our results show that for both species, environmental parameters only have minor influence, whereas crystal growth rate strongly influences trace elements concentrations, especially for Sr (explaining up to 74% of the variance). The relationship between G and Sr/Ca exhibits variability among the shells as well as inside the shells. For a same growth rate value, Sr/Ca values are higher in more curved shell sections, and the growth rate influence is stronger as well. We show that intercellular and Ca 2+-pump pathways cannot support the calcification Ca 2+ flux, leading us to propose an alternative mechanism for ionic transport through the calcifying mantle, implying a major role for calcium channels on mantle epithelial cell membranes. In this new calcification model, Sr/Ca shell ratios is determined by Ca 2+-channel selectivity against Sr 2+, which depends (i) on the electrochemical potential imposed by the crystallisation process and (ii) on the Ca 2+-channel density per surface unit on mantle epithelia.

  13. [Pathology of coronary arterial calcification].

    PubMed

    Yutani, Chikao

    2007-03-01

    Calcification is an invariable component of advanced coronary artery atherosclerosis. Recent study showed that genetic variations such as matrix inhibitory proteins, polymorphisms for tumor necrosis factor, and inflammatory cytokines may influence coronary artery calcification. And also there have been numerous studies on screening patients for coronary artery disease using electron beam computed tomography, but details of mechanism on calcification have still been unclear. An example of coronary calcification in diabetic patients disclosed that its diffuse distribution might be metabolic on calcification mechanism.

  14. 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.

  15. [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.

  16. Influence of plaque calcifications on coronary stent fracture: a numerical fatigue life analysis including cardiac wall movement.

    PubMed

    Morlacchi, Stefano; Pennati, Giancarlo; Petrini, Lorenza; Dubini, Gabriele; Migliavacca, Francesco

    2014-03-03

    Coronary stent fracture is still an unresolved issue in the field of minimally invasive cardiovascular interventions due to its high rate of incidence and uncertain clinical consequences. Recent studies, based on clinical data, proved that there are several factors which can be identified as independently responsible of coronary stent fracture. Among these, calcifications, which increase the local stiffness and heterogeneity of atherosclerotic plaques, seem to play a major role. From a mechanical point of view, stent fracture in coronary arteries is triggered by the cyclic loading of pulsatile blood pressure combined with the movement of cardiac wall. In this context, this study aims at simulating the stent expansion in a model of epicardial atherosclerotic coronary artery and correlating the effects of cyclic blood pressure and cardiac wall movement on the stent fatigue resistance. Two ideal cases of atherosclerotic plaques were modelled: the first one included a localised plaque calcification; the latter one did not include such calcification. Results of stress/strain and fatigue analyses confirmed the influence of the plaque calcification on potential fracture of the devices. In addition, the effects of cardiac wall movement were quantified as more dangerous causes of the stent fatigue fracture with respect to the internal blood pressure oscillations. In conclusion, this study demonstrates the increased risk of coronary stent fracture associated to the presence of localised plaque calcifications. This work also suggests the necessity of more realistic biomechanical models which takes into account the heterogeneity of atherosclerotic plaques in order to assess the mechanical performances of coronary stents.

  17. The Influence of Seawater pH on Respiration, Calcification, and Mg/Ca in the Cultured Foraminifer Globigerina bulloides

    NASA Astrophysics Data System (ADS)

    Davis, C. V.; Rivest, E.; Russell, A. D.; Spero, H. J.; Gaylord, B.; Sanford, E.; Hill, T. M.

    2016-02-01

    Planktic foraminifera are excellent recorders of water column chemistry and play a key role in planktic ecosystems and open ocean inorganic carbon flux. Perturbations to the oceanic inorganic carbon system, due to global or regional decreases in seawater pH, have the potential to profoundly affect foraminifera and their contribution to the biological carbon pump. Previous culture and field studies have documented a decrease in calcification in planktic foraminifera when exposed to low pH and low concentrations of carbonate ion. Incorporating physiological as well as trace metal analyses in the study of these planktic organisms will improve (a) our understanding of how the role of foraminifera in planktic ecosystems will change in the future as well as (b) our interpretation of shell geochemical proxies to reconstruct paleoenvironment conditions. We utilize a novel combination of metrics, including respirometry and fluorescent labeling of calcite, to better understand the impact of pH on foraminiferal metabolism and the relationship between oxygen consumption and calcification. The planktic foraminifer, Globigerina bulloides, was cultured across a range of treatments from 7.5 < pH > 8.2. Incorporation of fluorescent calcein dye into shells along with measurements of oxygen consumption showed that both oxygen consumption and calcification responded to changes in environmental pH. Shells with new chambers grown in culture were additionally analyzed for trace element content by Laser-Ablation Inductively Coupled Plasma Mass Spectrometry. Both calcification and the incidence of spine repair decreased under lowered pH. By contrast, the response of oxygen consumption to decreasing pH was parabolic, declining at pH levels above and below pH 8. Our results suggest that both performance and calcification are likely to be impacted by future changes in global and regional pH, and past variability in pH may influence how individual foraminifera shells can be interpreted as

  18. Crystallization by Particle Attachment: New Paradigm for Predicting Influences of Environmental Change on Calcification Processes

    NASA Astrophysics Data System (ADS)

    Dove, P. M.; De Yoreo, J. J.

    2016-02-01

    Traditional approaches to interpreting the formation of marine biominerals were founded on the classical models of crystal growth that were based on observations of mineral systems with high solubility. In these systems growth is dominated by attachment of individual ions to step edges. As Earth scientists began to use high-resolution and in situ TEM methods to investigate the growth of biological minerals and sparingly soluble synthetic materials, the importance of nanoparticle assembly became important. These studies show that the formation of many biominerals cannot be explained solely by the monomer-by-monomer addition of classical models. Rather, the process begins by forming particles that can begin as small molecules, clusters, droplets, or nanocrystals. The particles subsequently interact to give rise to crystalline structures. Evidence from biological and synthetic studies shows crystallization by particle attachment (CPA) processes are widespread (De Yoreo et al., 2015, Science), and possibly a prevailing type of crystal growth. This presentation will outline the dominant pathways for CPA and show evidence for how carbonate mineralization occurs by this process. The revised picture of biominerals is based in evidence from natural and experimental samples and rooted in thermodynamic and kinetic principles. While there is much to be learned about the nature of particle-particle interactions, CPA offers a process-based construct for deciphering chemical signatures and predicting how changing environmental conditions will influence calcification.

  19. Pineal calcification.

    PubMed

    Bhatti, I H; Khan, A

    1977-04-01

    The incidence of pineal calcification was studied by reviewing skull radiographs of 1400 patients admitted to a major neurosurgical centre at Karachi over an eight year period. The total frequency as well as age and sex distribution of pineal calcification were worked out and compared with frequency and age distribution of calcification reported in Western and Eastern races by different workers.

  20. Arterial calcifications

    PubMed Central

    Rennenberg, Roger J M W; Schurgers, Leon J; Kroon, Abraham A; Stehouwer, Coen D A

    2010-01-01

    Abstract Arterial calcifications as found with various imaging techniques, like plain X-ray, computed tomography or ultrasound are associated with increased cardiovascular risk. The prevalence of arterial calcification increases with age and is stimulated by several common cardiovascular risk factors. In this review, the clinical importance of arterial calcification and the currently known proteins involved are discussed. Arterial calcification is the result of a complex interplay between stimulating (bone morphogenetic protein type 2 [BMP-2], RANKL) and inhibitory (matrix Gla protein, BMP-7, osteoprotegerin, fetuin-A, osteopontin) proteins. Vascular calcification is especially prevalent and related to adverse outcome in patients with renal insufficiency and diabetes mellitus. We address the special circumstances and mechanisms in these patient groups. Treatment and prevention of arterial calcification is possible by the use of specific drugs. However, it remains to be proven that reduction of vascular calcification in itself leads to a reduced cardiovascular risk. PMID:20716128

  1. Time-dependent change in fresh autologous pericardium applied for posterior mitral annuloplasty: degree of calcification and its influence on the repaired mitral valve.

    PubMed

    Miura, Takashi; Eishi, Kiyoyuki; Sakamoto, Ichiro; Yamachika, Shiro; Hashizume, Kouji; Yamane, Kentaro; Tanigawa, Kazuyoshi; Matsukuma, Seiji; Nakaji, Shun

    2012-06-01

    To investigate the degree of calcification of fresh autologous pericardium applied for posterior mitral annuloplasty and its influence on the repaired mitral valve. Thirty-nine patients (31 degenerative and 8 infective endocarditis; mean age at surgery: 62 ± 11 years) were enrolled in this study. Sixteen-slice multi-detector computed tomography was performed to identify calcification of autologous pericardium. The mean clinical follow-up was 4.6 ± 2.6 years (maximum 8.8 years) and the mean computed tomography follow-up period was 3.6 ± 2.5 years (maximum 7.6 years) after surgery. Pericardial calcification was detected in 15 patients. The earliest detection of calcification was 2.5 years after surgery. There was a weak correlation between pericardial calcification and postoperative years (Pearson's product correlation coefficient: 0.476; p = 0.0019). However, severe calcification of autologous pericardium did not occur in any case. There was no association between pericardial calcification and recurrent mitral regurgitation (p = 0.1145). The mean mitral valve orifice area and the mean transmitral pressure gradient in the 15 patients with calcification were 3.0 ± 0.6 cm(2) and 2.1 ± 1.0 mmHg, respectively. Calcification of the fresh autologous pericardium increased with postoperative years. It had no adverse effects on repaired mitral valve in the short-term follow-up period. We will report the findings once again when the follow-up reaches 10 years.

  2. Genetic Pathways of Vascular Calcification

    PubMed Central

    Bowman, Marion A. Hofmann; McNally, Elizabeth M.

    2012-01-01

    Vascular calcification is an independent risk factor for cardiovascular disease. Arterial calcification of the aorta, coronary, carotid and peripheral arteries becomes more prevalent with age. Genomewide association studies have identified regions of the genome linked to vascular calcification, and these same regions are linked to myocardial infarction risk. The 9p21 region linked to vascular disease and inflammation also associates with vascular calcification. In addition to these common variants, rare genetic defects can serve as primary triggers of accelerated and premature calcification. Infancy-associated calcific disorders are caused by loss of function mutations in ENPP1 an enzyme that produces extracellular pyrophosphate. Adult onset vascular calcification is linked to mutations NTE5, another enzyme that regulates extracellular phosphate metabolism. Common conditions that secondarily enhance vascular calcification include atherosclerosis, metabolic dysfunction, diabetes, and impaired renal clearance. Oxidative stress and vascular inflammation, along with biophysical properties, converge with these predisposing factors to promote soft tissue mineralization. Vascular calcification is accompanied by an osteogenic profile, and this osteogenic conversion is seen within the vascular smooth muscle itself as well as the matrix. Herein we will review the genetic causes of medial calcification in the smooth muscle layer, focusing on recent discoveries of gene mutations that regulate extracellular matrix phosphate production and the role of S100 proteins as promoters of vascular calcification. PMID:23040839

  3. 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. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Ocean acidification adversely influences metabolism, extracellular pH and calcification of an economically important marine bivalve, Tegillarca granosa.

    PubMed

    Zhao, Xinguo; Shi, Wei; Han, Yu; Liu, Saixi; Guo, Cheng; Fu, Wandong; Chai, Xueliang; Liu, Guangxu

    2017-04-01

    Oceanic uptake of CO2 from the atmosphere has significantly reduced surface seawater pH and altered the carbonate chemistry within, leading to global Ocean Acidification (OA). The blood clam, Tegillarca granosa, is an economically and ecologically significant marine bivalve that is widely distributed along the coastal and estuarine areas of Asia. To investigate the physiological responses to OA, blood clams were exposed to ambient and three reduced seawater pH levels (8.1, 7.8, 7.6 and 7.4) for 40 days, respectively. Results obtained suggest that OA suppresses the feeding activity and aerobic metabolism, but elevates proteins catabolism of blood clams. OA also causes extracellular acidosis and decreases haemolymph Ca(2+) concentration. In addition, our data also suggest that OA impairs the calcification process and inner shell surface integrity. Overall, OA adversely influences metabolism, acid-base status and calcification of blood clams, subsequently leading to a decrease in the fitness of this marine bivalve species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Breast Calcifications

    MedlinePlus

    ... remain unchanged. References What mammograms show: Calcifications, cysts, fibroadenomas. Breastcancer.org. http://www.breastcancer.org/symptoms/testing/types/mammograms/mamm_show. Accessed Dec. 9, 2015. Mammograms and other breast imaging tests. American Cancer Society. http://www.cancer. ...

  6. 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

  7. Lanthanum chloride bidirectionally influences calcification in bovine vascular smooth muscle cells.

    PubMed

    Zhao, Wen-Hua; Gou, Bao-Di; Zhang, Tian-Lan; Wang, Kui

    2012-05-01

    Vascular calcification (VC) is frequent prevalence in patients with chronic kidney disease (CKD) and atherosclerosis. Lanthanum carbonate is used as an orally administered phosphate-binding agent to reduce the gastrointestinal absorption of phosphate and ameliorate VC in advanced CKD. In this study, we used bovine vascular smooth muscle cells as a model VC in vitro and studied the effects of lanthanum chloride on calcium deposition. Exposure of cells to LaCl(3) at the concentration of 0.1 µM suppressed the β-glycerophosphate-induced alkaline phosphatase activity and calcium deposition. Furthermore, LaCl(3) upregulated the β-glycerophosphate-suppressed expression of calcium-sensing receptor. In contrast to the inhibitory effect of LaCl(3) on calcium deposition, higher level lanthanum (50 µM) was found to promote immediately precipitation of calcium phosphate in cell culture medium. At this concentration, LaCl(3) was found to induce cell apoptosis which involves caspases-9 and -3. These data indicate that the promotory effect of LaCl(3) on calcium deposition is likely mediated by induction of apoptosis. Our in vitro findings do suggest that, in the context of raised lanthanum, greater attention should be paid to potential toxic effects associated to the use of lanthanide-based drugs.

  8. 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

  9. 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-].

  10. [THE CHANGES IN THE STRUCTURAL REMODELING OF THE CAROTID ARTERY IN PATIENTS WITH HYPERTENSION AND HEART VALVE CALCIFICATION UNDER THE INFLUENCE OF TREATMENT].

    PubMed

    Yuzvishina, O V

    2014-01-01

    In patients with essential hypertension (EH) and heart valves calcification (HVC) were studied the dynamics of the structural remodeling of the carotid artery under the influence of different variants of lipid-lowering therapy. Significant decrease in the thickness of the intimamedia, the frequency of new atherosclerotic plaques have been seen in patients with EH and HVC using high-dose atorvastatin compared with less.

  11. Vascular calcification in maintenance hemodialysis patients.

    PubMed

    Wang, Mi; Wang, Mei; Gan, Liang-Ying; Li, Si-Jun; Hong, Nan; Zhang, Meng

    2009-01-01

    The objective was to investigate the status of vascular calcification, and to explore factors influencing vascular calcification in maintenance hemodialysis patients. Vascular calcification was quantitatively evaluated using radiographic films of the abdomen, pelvis and hands. Plasma fetuin-A and other parameters related to calcification were examined. 33/50 cases of vascular calcification were identified by radiographic film. Calcifications of the abdominal aorta and peripheral muscular arteries were seen in 90.9 and 36.4%. Patients with moderate to severe calcification were older, more likely to be male, had lower diastolic blood pressure and fetuin-A levels, and a higher incidence of diabetes than those with mild calcification. Logistic regression analysis showed that diabetes and plasma fetuin-A were independent risk factors for vascular calcification. Vascular calcification was present in a large proportion of maintenance hemodialysis patients, most frequently in the abdominal aorta. Diabetes and plasma fetuin-A levels were independent risk factors for vascular calcification in maintenance hemodialysis patients. (c) 2009 S. Karger AG, Basel.

  12. Ultrastructural Analysis of Vascular Calcifications in Uremia

    PubMed Central

    Aretz, Anke; Verberckmoes, Steven C.; Krüger, Thilo; Behets, Geert J.; Ghadimi, Reza; Weirich, Thomas E.; Rohrmann, Dorothea; Langer, Stephan; Tordoir, Jan H.; Amann, Kerstin; Westenfeld, Ralf; Brandenburg, Vincent M.; D'Haese, Patrick C.; Mayer, Joachim; Ketteler, Markus; McKee, Marc D.; Floege, Jürgen

    2010-01-01

    Accelerated intimal and medial calcification and sclerosis accompany the increased cardiovascular mortality of dialysis patients, but the pathomechanisms initiating microcalcifications of the media are largely unknown. In this study, we systematically investigated the ultrastructural properties of medial calcifications from patients with uremia. We collected iliac artery segments from 30 dialysis patients before kidney transplantation and studied them by radiography, microcomputed tomography, light microscopy, and transmission electron microscopy including electron energy loss spectrometry, energy dispersive spectroscopy, and electron diffraction. In addition, we performed synchrotron x-ray analyses and immunogold labeling to detect inhibitors of calcification. Von Kossa staining revealed calcification of 53% of the arteries. The diameter of these microcalcifications ranged from 20 to 500 nm, with a core-shell structure consisting of up to three layers (subshells). Many of the calcifications consisted of 2- to 10-nm nanocrystals and showed a hydroxyapatite and whitlockite crystalline structure and mineral phase. Immunogold labeling of calcification foci revealed the calcification inhibitors fetuin-A, osteopontin, and matrix gla protein. These observations suggest that uremic microcalcifications originate from nanocrystals, are chemically diverse, and intimately associate with proteinaceous inhibitors of calcification. Furthermore, considering the core-shell structure of the calcifications, apoptotic bodies or matrix vesicles may serve as a calcification nidus. PMID:20203159

  13. 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

  14. Vascular Calcification: an Update on Mechanisms and Challenges in Treatment

    PubMed Central

    Wu, Meiting; Rementer, Cameron; Giachelli, Cecilia M.

    2013-01-01

    Vascular calcification is highly associated with cardiovascular disease mortality, particularly in high risk patients with diabetes and chronic kidney diseases (CKD). In blood vessels, intimal calcification is associated with atherosclerosis, whereas medial calcification is a non-occlusive process which leads to increased vascular stiffness and reduced vascular compliance. In the valves, calcification of the leaflets can change the mechanical properties of the tissue and result in stenosis. For many decades, vascular calcification has been noted as a consequence of aging. Studies now confirm that vascular calcification is an actively regulated process and shares many features with bone development and metabolism. This review provides an update on the mechanisms of vascular calcification including the emerging roles of the RANK/RANKL/OPG triad, osteoclasts and microRNAs. Potential treatments adapted from osteoporosis and CKD treatments that are under investigation for preventing and/or regressing vascular calcification will also be reviewed. PMID:23456027

  15. Familial calcific periarthritis.

    PubMed Central

    Hajiroussou, V J; Webley, M

    1983-01-01

    A family of 4 is described in which both children had calcific periarthritis affecting the shoulders, and the mother had radiological evidence of periarticular calcification near the left greater trochanter. PMID:6882045

  16. Warming influences Mg2+ content, while warming and acidification influence calcification and test strength of a sea urchin.

    PubMed

    Byrne, Maria; Smith, Abigail M; West, Samantha; Collard, Marie; Dubois, Philippe; Graba-landry, Alexia; Dworjanyn, Symon A

    2014-11-04

    We examined the long-term effects of near-future changes in temperature and acidification on skeletal mineralogy, thickness, and strength in the sea urchin Tripneustes gratilla reared in all combinations of three pH (pH 8.1, 7.8, 7.6) and three temperatures (22 °C, 25 °C, 28 °C) from the early juvenile to adult, over 146 days. As the high-magnesium calcite of the echinoderm skeleton is a biomineral form highly sensitive to acidification, and influenced by temperature, we documented the MgCO3 content of the spines, test plates, and teeth. The percentage of MgCO3 varied systematically, with more Mg2+ in the test and spines. The percentage of MgCO3 in the test and teeth, but not the spines increased with temperature. Acidification did not change the percentage MgCO3. Test thickness increased with warming and decreased at pH 7.6, with no interaction between these factors. In crushing tests live urchins mostly ruptured at sutures between the plates. The force required to crush a live urchin was reduced in animals reared in low pH conditions but increased in those reared in warm conditions, a result driven by differences in urchin size. It appears that the interactive effects of warming and acidification on the Mg2+ content and protective function of the sea urchin skeleton will play out in a complex way as global climatic change unfolds.

  17. 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. Copyright © 2015

  18. Genetics in Arterial Calcification

    PubMed Central

    Rutsch, Frank; Nitschke, Yvonne; Terkeltaub, Robert

    2011-01-01

    Artery calcification reflects an admixture of factors such as ectopic osteochondral differentiation with primary host pathological conditions. We review how genetic factors, as identified by human genome-wide association studies, and incomplete correlations with various mouse studies, including knockout and strain analyses, fit into “pieces of the puzzle” in intimal calcification in human atherosclerosis, and artery tunica media calcification in aging, diabetes mellitus, and chronic kidney disease. We also describe in sharp contrast how ENPP1, CD73, and ABCC6 serve as “cogs in a wheel” of arterial calcification. Specifically, each is a minor component in the function of a much larger network of factors that exert balanced effects to promote and suppress arterial calcification. For the network to normally suppress spontaneous arterial calcification, the “cogs” ENPP1, CD73, and ABCC6 must be present and in working order. Monogenic ENPP1, CD73, and ABCC6 deficiencies each drive a molecular pathophysiology of closely related but phenotypically different diseases (generalized arterial calcification of infancy (GACI), pseudoxan-thoma elasticum (PXE) and arterial calcification caused by CD73 deficiency (ACDC)), in which premature onset arterial calcification is a prominent but not the sole feature. PMID:21852556

  19. [Bisphosphonates for vascular calcification].

    PubMed

    Tanaka, Yoshiya; Okada, Yosuke

    2007-03-01

    Recent progress in basic research has revealed certain similarities between processes of bone calcification and calcifications of vascular tissues which contribute to several cardiovascular diseases. Bisphosphonates, which are inhibitors of bone resorption that are widely used to treat osteoporosis, also inhibit cholesterol biosynthesis, differentiation of macrophage to foam cell, differentiation of smooth muscle cells to osteoblast-like cells in certain stimuli during calcification processes of vessels. These findings extend the link between bone remodeling and vascular calcification, opening perspectives toward novel therapeutic strategies, however, current evidence is not conclusive and further research is necessary to confirm these actions in the clinical setting.

  20. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution: a cardiac phantom study.

    PubMed

    Greuter, M J W; Groen, J M; Nicolai, L J; Dijkstra, H; Oudkerk, M

    2009-11-01

    The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative method which corrects for the influences of these parameters using a linear moving cardiac phantom. On a robotic arm with artificial arteries with four calcifications of increasing density, a linear movement was applied between 0 and 120 mm/s (step of 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT, and EBT using a standard acquisition protocol. The average Agatston, volume, and mass scores were determined for each velocity, calcification, and scanner. Susceptibility to motion was quantified using a cardiac motion susceptibility (CMS) index. Resemblance to EBT and physical volume and mass was quantified using a Delta index. Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The calcium score showed a linear dependency on motion from which a correction factor could be derived. This correction factor showed a linear dependency on the mean calcification density with a good fit for all three scoring methods and all three scanners (0.73 < or = R2 < or = 0.95). The slope and offset of this correction factor showed a linear dependency on temporal resolution with a good fit for all three scoring methods and all three scanners (0.83 < or = R2 < or = 0.98). CMS was minimal for EBT and increasing values were observed for DSCT and highest values for 64-slice MDCT. CMS was minimal for mass score and increasing values were observed for volume score and highest values for Agatston score. For all densities and scoring methods DSCT showed on average the closest resemblance to EBT calcium scores. When using the correction factor, CMS index decreased on average by 15% and Delta index

  1. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution: A cardiac phantom study

    SciTech Connect

    Greuter, M. J. W.; Groen, J. M.; Nicolai, L. J.; Dijkstra, H.; Oudkerk, M.

    2009-11-15

    Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative method which corrects for the influences of these parameters using a linear moving cardiac phantom. Methods: On a robotic arm with artificial arteries with four calcifications of increasing density, a linear movement was applied between 0 and 120 mm/s (step of 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT, and EBT using a standard acquisition protocol. The average Agatston, volume, and mass scores were determined for each velocity, calcification, and scanner. Susceptibility to motion was quantified using a cardiac motion susceptibility (CMS) index. Resemblance to EBT and physical volume and mass was quantified using a {Delta} index. Results: Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The calcium score showed a linear dependency on motion from which a correction factor could be derived. This correction factor showed a linear dependency on the mean calcification density with a good fit for all three scoring methods and all three scanners (0.73{<=}R{sup 2}{<=}0.95). The slope and offset of this correction factor showed a linear dependency on temporal resolution with a good fit for all three scoring methods and all three scanners (0.83{<=}R{sup 2}{<=}0.98). CMS was minimal for EBT and increasing values were observed for DSCT and highest values for 64-slice MDCT. CMS was minimal for mass score and increasing values were observed for volume score and highest values for Agatston score. For all densities and scoring methods DSCT showed on average the closest resemblance to EBT calcium scores. When using the correction factor, CMS index decreased on average by

  2. Proton pumping accompanies calcification in foraminifera

    NASA Astrophysics Data System (ADS)

    Toyofuku, Takashi; Matsuo, Miki Y.; de Nooijer, Lennart Jan; Nagai, Yukiko; Kawada, Sachiko; Fujita, Kazuhiko; Reichart, Gert-Jan; Nomaki, Hidetaka; Tsuchiya, Masashi; Sakaguchi, Hide; Kitazato, Hiroshi

    2017-01-01

    Ongoing ocean acidification is widely reported to reduce the ability of calcifying marine organisms to produce their shells and skeletons. Whereas increased dissolution due to acidification is a largely inorganic process, strong organismal control over biomineralization influences calcification and hence complicates predicting the response of marine calcifyers. Here we show that calcification is driven by rapid transformation of bicarbonate into carbonate inside the cytoplasm, achieved by active outward proton pumping. Moreover, this proton flux is maintained over a wide range of pCO2 levels. We furthermore show that a V-type H+ ATPase is responsible for the proton flux and thereby calcification. External transformation of bicarbonate into CO2 due to the proton pumping implies that biomineralization does not rely on availability of carbonate ions, but total dissolved CO2 may not reduce calcification, thereby potentially maintaining the current global marine carbonate production.

  3. Proton pumping accompanies calcification in foraminifera

    PubMed Central

    Toyofuku, Takashi; Matsuo, Miki Y.; de Nooijer, Lennart Jan; Nagai, Yukiko; Kawada, Sachiko; Fujita, Kazuhiko; Reichart, Gert-Jan; Nomaki, Hidetaka; Tsuchiya, Masashi; Sakaguchi, Hide; Kitazato, Hiroshi

    2017-01-01

    Ongoing ocean acidification is widely reported to reduce the ability of calcifying marine organisms to produce their shells and skeletons. Whereas increased dissolution due to acidification is a largely inorganic process, strong organismal control over biomineralization influences calcification and hence complicates predicting the response of marine calcifyers. Here we show that calcification is driven by rapid transformation of bicarbonate into carbonate inside the cytoplasm, achieved by active outward proton pumping. Moreover, this proton flux is maintained over a wide range of pCO2 levels. We furthermore show that a V-type H+ ATPase is responsible for the proton flux and thereby calcification. External transformation of bicarbonate into CO2 due to the proton pumping implies that biomineralization does not rely on availability of carbonate ions, but total dissolved CO2 may not reduce calcification, thereby potentially maintaining the current global marine carbonate production. PMID:28128216

  4. [Mechanisms of bone calcification].

    PubMed

    Hoshi, Kazuto

    2007-10-01

    In bone calcification, hydroxyapatite is crystallized on the type I collagen-based organic matrices. It occurs in the extracellular spaces. Osteoblasts trigger and promote the crystallization by the biological control to the secretion of various matrix proteins or enzymes. The author overviews the mineral and organic environments in calcification areas and the roles of osteoblasts in mineral/organic interaction.

  5. 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

  6. The influence of aortic valve calcification on the risk of periprocedural myocardial injury after elective coronary intervention.

    PubMed

    Chen, Zhang-Wei; Yang, Hong-Bo; Chen, Ying-Hua; Qian, Ju-Ying; Shu, Xian-Hong; Ge, Jun-Bo

    2015-10-01

    Aortic valve calcification (AVC) is a common progressive condition that involves several inflammatory and atherosclerotic mediators. However, it is unclear whether the occurrence of periprocedural myocardial injury (PMI) after elective coronary intervention is associated with AVC in stable coronary artery disease (CAD) patients. A total of 530 stable CAD patients who underwent elective coronary intervention were enrolled in this clinical study. High sensitive cardiac troponin T (hs-cTnT) was detected before and after the procedure. PMI was defined as hs-cTnT after coronary intervention higher than 99th percentile upper reference limit (URL). All patients underwent echocardiography to detect the occurrence of AVC. Univariate and multivariate analyses were applied to analyze risk factors of PMI. A total of 210 patients (39.6 %) were diagnosed with PMI after elective coronary intervention. Compared with non-AVC patients (n = 386), AVC patients (n = 144) had higher rate of PMI (64.6 vs. 30.3 %, P < 0.01). CAD patients with AVC had higher Gensini score (39.9 ± 26.6 vs. 34.2 ± 22.1, P < 0.05) and more number of implanted stents (1.7 ± 0.8 vs. 1.5 ± 0.7, P < 0.05). After stratification by classic risk factors of CAD (such as age, male gender and diabetes) in subgroup analyses, we found that AVC patients had increased risk of PMI compared with non-AVC patients. Importantly, even after being adjusted by multivariate analysis, AVC still independently increased the risk of PMI (OR = 3.329, 95 % CI = 2.087-5.308, P < 0.01). AVC significantly increased the risk of PMI after elective coronary intervention. It could be one of the independent predictors for PMI in stable CAD patients.

  7. Regulating in vivo calcification of alginate microbeads

    PubMed Central

    Lee, Christopher S.D.; Moyer, Hunter R.; Gittens, Rolando A.; Williams, Joseph K.; Boskey, Adele L.; Boyan, Barbara D.; Schwartz, Zvi

    2012-01-01

    Alginate calcification has been previously reported clinically and during animal implantation; however no study has investigated the mechanism, extensively characterized the mineral, or evaluated multiple methods to regulate or eliminate mineralization. In the present study, alginate calcification was first studied in vitro: calcium-crosslinked alginate beads sequestered surrounding phosphate while forming traces of hydroxyapatite. Calcification in vivo was then examined in nude mice using alginate microbeads with and without adipose stem cells (ASCs). Variables included the delivery method, site of delivery, sex of the animal, time in vivo, crosslinking solution, and method of storage prior to delivery. Calcium-crosslinked alginate microbeads mineralized when injected subcutaneously or implanted intramuscularly after 1–6 months. More extensive analysis with histology, microCT, FTIR, XRD, and EDS showed calcium phosphate deposits throughout the microbeads with surface mineralization that closely matched hydroxyapatite found in bone. Incorporating 25 mM bisphosphonate reduced alginate calcification whereas using barium chloride eliminated mineralization. Buffering the crosslinking solution with HEPES at pH 7.3 while washing and storing samples in basal media prior to implantation also eliminated calcification in vivo. This study shows that alginate processing prior to implantation can significantly influence bulk hydroxyapatite formation and presents a method to regulate alginate calcification. PMID:20363022

  8. Regulating in vivo calcification of alginate microbeads.

    PubMed

    Lee, Christopher S D; Moyer, Hunter R; Gittens, Rolando A I; Williams, Joseph K; Boskey, Adele L; Boyan, Barbara D; Schwartz, Zvi

    2010-06-01

    Alginate calcification has been previously reported clinically and during animal implantation; however no study has investigated the mechanism, extensively characterized the mineral, or evaluated multiple methods to regulate or eliminate mineralization. In the present study, alginate calcification was first studied in vitro: calcium-crosslinked alginate beads sequestered surrounding phosphate while forming traces of hydroxyapatite. Calcification in vivo was then examined in nude mice using alginate microbeads with and without adipose stem cells (ASCs). Variables included the delivery method, site of delivery, sex of the animal, time in vivo, crosslinking solution, and method of storage prior to delivery. Calcium-crosslinked alginate microbeads mineralized when injected subcutaneously or implanted intramuscularly after 1-6 months. More extensive analysis with histology, microCT, FTIR, XRD, and EDS showed calcium phosphate deposits throughout the microbeads with surface mineralization that closely matched hydroxyapatite found in bone. Incorporating 25 mm bisphosphonate reduced alginate calcification whereas using barium chloride eliminated mineralization. Buffering the crosslinking solution with HEPES at pH 7.3 while washing and storing samples in basal media prior to implantation also eliminated calcification in vivo. This study shows that alginate processing prior to implantation can significantly influence bulk hydroxyapatite formation and presents a method to regulate alginate calcification. (c) 2010 Elsevier Ltd. All rights reserved.

  9. Calcific neurocysticercosis and epileptogenesis

    PubMed Central

    Nash, T.E.; Del Brutto, O.H.; Butman, J.A.; Corona, T.; Delgado-Escueta, A.; Duron, R.M.; Evans, C.A.W.; Gilman, R.H.; Gonzalez, A.E.; Loeb, J.A.; Medina, M.T.; Pietsch-Escueta, S.; Pretell, E.J.; Takayanagui, O.M.; Theodore, W.; Tsang, V.C.W.; Garcia, H.H.

    2010-01-01

    Neurocysticercosis is responsible for increased rates of seizures and epilepsy in endemic regions. The most common form of the disease, chronic calcific neurocysticercosis, is the end result of the host’s inflammatory response to the larval cysticercus of Taenia solium. There is increasing evidence indicating that calcific cysticercosis is not clinically inactive but a cause of seizures or focal symptoms in this population. Perilesional edema is at times also present around implicated calcified foci. A better understanding of the natural history, frequency, epidemiology, and pathophysiology of calcific cysticercosis and associated disease manifestations is needed to define its importance, treatment, and prevention. PMID:15184592

  10. 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.

  11. Heart in An Eggshell Calcification: Idiopathic Calcific Constrictive Pericarditis

    PubMed Central

    Song, Bong Gun; Kang, Gu Hyun; Park, Yong Hwan; Chun, Woo Jung; Oh, Ju Hyeon

    2011-01-01

    Constrictive pericarditis is caused by fibrosis and calcification of the pericardium, which inhibits diastolic filling of the heart. Chest roentgenogram can show the calcification as a mass or sheet over the heart and computed tomography scan allows anatomic delineation of the pericardium and determines the extent of calcification. We reported a case of eggshell calcification of idiopathic chronic constrictive pericarditis diagnosed by echocardiography and multi-detector computed tomography.

  12. Control of guided hard-tissue regeneration using phosphorylated gelatin and OCT imaging of calcification

    NASA Astrophysics Data System (ADS)

    Ishii, Katsunori; Ma, Zhenhe; Ninomiya, Yoshihisa; Takegoshi, Minori; Kushibiki, Toshihiro; Yamamoto, Masaya; Hinds, Monica; Tabata, Yasuhiko; Wang, Ruikang K.; Awazu, Kunio

    2007-02-01

    Tendon and ligament are the transition tissues from a hard tissue to a soft tissue. The regenerative medicine of tendons needs reasonable biomaterials to regenerate precisely from the view point of composition and adhesion properties. In regenerative medicine of hard tissues, it has been reported that calcifications are influenced by phosphorylated proteins (phosphate groups) and the biomaterial possessing phosphate groups promote or inhibit the formation of HAP. We have studied to develop and evaluate the phosphorylated soft biomaterials, which is possible to control a calcification by the introduction ratio of phosphate groups, as biomaterials for tendon regeneration. In addition, we have studied measurement technologies. In the present study, we studied a FT-IR analysis of gelatins with different introduction ratio of phosphate groups, an evaluation of calcifications by the difference of introduction ratio of phosphate groups, and a fundamental survey on OCT imaging for calcifications of a gelatin and a phosphorylated gelatin. We use phosphorylated gelatins with different introduction ratios of phosphate group linked by ester bonds. The introduction ratios are measured by the FT-IR calibrated by a molybdenum blue method. Phosphorylated gelatin sheets were calcified using 1.5SBF soaking process and alternative soaking process. These gelatin sheets with different calcification conditions were measured using SD-OCT systems with 843nm centered wavelength SLD. As a result, we demonstrated that it was possible to measure the calcification on/in the gelatin sheets and sponges and phosphorylated using OCT. The main mechanism is the strong back scattering and the high scattering of deposited calcium particles.

  13. Fibroblast involvement in soft connective tissue calcification

    PubMed Central

    Ronchetti, Ivonne; Boraldi, Federica; Annovi, Giulia; Cianciulli, Paolo; Quaglino, Daniela

    2013-01-01

    Soft connective tissue calcification is not a passive process, but the consequence of metabolic changes of local mesenchymal cells that, depending on both genetic and environmental factors, alter the balance between pro- and anti-calcifying pathways. While the role of smooth muscle cells and pericytes in ectopic calcifications has been widely investigated, the involvement of fibroblasts is still elusive. Fibroblasts isolated from the dermis of pseudoxanthoma elasticum (PXE) patients and of patients exhibiting PXE-like clinical and histopathological findings offer an attractive model to investigate the mechanisms leading to the precipitation of mineral deposits within elastic fibers and to explore the influence of the genetic background and of the extracellular environment on fibroblast-associated calcifications, thus improving the knowledge on the role of mesenchymal cells on pathologic mineralization. PMID:23467434

  14. 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

  15. Acute Prevertebral Calcific Tendinitis.

    PubMed

    Tamm, Alexander; Jeffery, Caroline C; Ansari, Khalid; Naik, Sandeep

    2015-11-01

    We present a case of neck pain in a middle-aged woman, initially attributed to a retropharyngeal infection and treated with urgent intubation. With the help of computed tomography, the diagnosis was later revised to acute prevertebral calcific tendinitis, a self-limiting condition caused by abnormal calcium hydroxyapatite deposition in the longus colli muscles. It is critical to differentiate between these two disease entities due to dramatic differences in management. A discussion of acute prevertebral calcific tendinitis and its imaging findings is provided below.

  16. 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

  17. 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

  18. 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

  19. The Role of Inorganic Pyrophosphate in Aortic Valve Calcification

    PubMed Central

    Rathan, Swetha; Yoganathan, Ajit P.; O’Neill, W. Charles

    2017-01-01

    Background and aim of the study Aortic valve (AV) calcification is a major cause of morbidity and mortality, yet the molecular mechanisms involved are poorly understood. Hence, an ex vivo model of calcification in intact AVs was developed in order to test the role of orthophosphate and pyrophosphate (PPi), both of which factors are known to influence vascular calcification. Methods Porcine AV leaflets were cultured in serum-free medium under static conditions for eight days, over which time leaflet architecture and viability were preserved. Calcification was measured as the incorporation of 45Ca, with confirmation by Alizarin Red staining. Results Calcification required both a high phosphate concentration (3.8 mM) and removal of PPi with alkaline phosphatase or inorganic pyrophosphatase. Calcification occurred predominantly on the fibrosa and was arrested by the bisphosphonate etidronate, a non-hydrolyzable analog of PPi. Leaflets released PPi into the medium, and this was enhanced by MLS38949, a specific inhibitor of tissue non-specific alkaline phosphatase (TNAP). Furthermore, leaflets synthesized PPi from extracellular ATP, which was reduced by β, γ-methylene-ATP, an inhibitor of ectonucleotide pyrophosphorylase phosphodiesterase (NPP1). Conclusion The ex vivo AV calcification model developed in the present study showed that extracellular PPi, produced by valvular tissue, is a potent inhibitor of valvular calcification. In addition to synthesis, hydrolysis by TNAP also controls PPi levels and calcification. The results suggest that a decreased synthesis or increased hydrolysis of pyrophosphate may contribute to valvular calcification, and that bisphosphonates or inhibitors of TNAP are potential preventive strategies of the process. TNAP are potential preventive strategies. PMID:25803964

  20. Rectus Femoris Tendon Calcification

    PubMed Central

    Zini, Raul; Panascì, Manlio; Papalia, Rocco; Franceschi, Francesco; Vasta, Sebastiano; Denaro, Vincenzo

    2014-01-01

    Background: Since it was developed, hip arthroscopy has become the favored treatment for femoroacetabular impingement. Due to recent considerable improvements, the indications for this technique have been widely extended. Injuries of the rectus femoris tendon origin, after an acute phase, could result in a chronic tendinopathy with calcium hydroxyapatite crystal deposition, leading to pain and loss of function. Traditionally, this condition is addressed by local injection of anesthetic and corticosteroids or, when conservative measures fail, by open excision of the calcific lesion by an anterior approach. Purpose: To assess whether arthroscopic excision of calcification of the proximal rectus is a safe and effective treatment. Study Design: Case series; Level of evidence, 4. Methods: Outcomes were studied from 6 top amateur athletes (age range, 30-43 years; mean, 32.6 years) affected by calcification of the proximal rectus who underwent arthroscopic excision of the calcification. Patients were preoperatively assessed radiographically, and diagnosis was confirmed by a 3-dimensional computed tomography scan. To evaluate the outcome, standardized hip rating scores were used pre- and postoperatively (at 6 and 12 months): the Hip disability and Osteoarthritis Outcome Score, Oxford Hip Score, and Modified Harris Hip Score. Moreover, visual analog scales (VAS) for pain, sport activity level (SAL), and activities of daily living (ADL) were also used. Results: One year after surgery, all patients reported satisfactory outcomes, with 3 of 6 rating their return-to-sport level as high as preinjury level, and the remaining 3 with a percentage higher than 80%. Five patients ranked their ability to carry on daily activities at 100%. Statistical analysis showed significant improvement of the Oxford Hip Score, the Modified Harris Hip Score, and all 3 VAS subscales (pain, SAL, and ADL) from pre- to latest postoperative assessment (P < .05). Conclusion: Arthroscopic excision of

  1. Placental calcification: a metastatic process?

    PubMed

    Poggi, S H; Bostrom, K I; Demer, L L; Skinner, H C; Koos, B J

    2001-07-01

    Placental calcification commonly increases with gestational age. The mechanism of apatite mineralization probably involves one of three known mechanisms of tissue calcification: physiological (like bone), dystrophic (ischaemia-related) or metastatic (mineralization in a supersaturated environment). This study was designed to determine the mechanism of calcification by examining (1) the mineral content of placental calcifications in comparison to other physiological and pathological apatites, and (2) the expression of bone morphogenetic proteins (BMPs), which are important in physiological calcification, across gestational age. By energy-dispersive x-ray analysis (EDXA), the Ca/P weight ratio for apatitic mineral from mature calcifications was 2.00+/-0.05 (s.e.), which is similar to that for stones formed in a metastatic, supersaturated environment and lower than that observed in physiological calcification. Biologically active BMP, which was determined by bioassay, was demonstrated in mature and postmature placentae. The BMPs PLAB, PDF and related protein INSL-4 were identified by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), but their mRNA expression was independent of gestational age (7-41 weeks of gestation). We conclude that (1) the identified BMPs were not related directly to placental calcification, which argues against physiological calcification, and (2) the chemical composition of the apatitic mineral was suggestive of rapid formation in a supersaturated environment, which is consistent with a metastatic mechanism of calcification.

  2. Inducers and inhibitors of biomineralization: lessons from pathological calcification.

    PubMed

    Giachelli, C M

    2005-11-01

    Ectopic calcification is a common response to soft tissue injury and systemic mineral imbalance and can lead to devastating clinical consequences when present in joints, heart valves and blood vessels. We have hypothesized that mineralization of matrices in any tissue is normally controlled by a balance between procalcific and anticalcific regulatory proteins such that abnormal deposition of apatite is avoided. Alterations in this balance induced by injury, disease or genetic deficiency are postulated to induce ectopic mineral deposition. Over the past several years, we have developed in vitro and in vivo models of ectopic calcification to investigate potential inducers and inhibitors of this process. Osteopontin, a secreted phosphoprotein, has emerged as a major inhibitor of ectopic mineralization. Osteopontin is a potent inhibitor of vascular cell calcification in vitro and mice lacking osteopontin are highly susceptible to ectopic calcification. Furthermore, osteopontin treatment of biomaterials protected against ectopic mineralization. Our studies indicate that in addition to inhibiting apatite crystal initiation and growth, osteopontin stimulates resorption of ectopic calcification via peripheral macrophages and giant cells. In contrast, inorganic phosphate has emerged as a major inducer of mineralization in these systems. Elevated inorganic phosphate (Pi) was shown to induce smooth muscle cell matrix calcification with morphological properties similar to those observed in calcified human valves and atherosclerotic plaques. Furthermore, mineralization induced by inorganic phosphate was dependent on the activity of the sodium-dependent phosphate cotransporter, Pit-1. These studies implicate controlled, transcellular transport of Pi as a major requirement for matrix calcification.

  3. Influence of atorvastatin on coronary calcifications and myocardial perfusion defects in systemic lupus erythematosus patients: a prospective, randomized, double-masked, placebo-controlled study.

    PubMed

    Plazak, Wojciech; Gryga, Krzysztof; Dziedzic, Hanna; Tomkiewicz-Pajak, Lidia; Konieczynska, Malgorzata; Podolec, Piotr; Musial, Jacek

    2011-07-20

    Mortality in systemic lupus erythematosus (SLE) patients is influenced by an increased occurrence of severe cardiovascular complications. Statins have been proven to protect a wide spectrum of SLE patients from these complications. This study was conducted to determine the possible efficacy of atorvastatin in SLE patients as assessed by multi-detector computed tomography (MDCT)-based coronary calcium scoring and single photon emission computed tomography (SPECT) of the myocardium. Sixty SLE patients in stable clinical conditions were randomized to receive either atorvastatin (40 mg daily; n = 28) or placebo (n = 32). Clinical and biochemical evaluation together with MDCT-based coronary calcium scoring and SPECT studies (Tc-99 m sestamibi) were performed at the time of randomization and after 1 year of treatment. At randomization, SPECT revealed perfusion defects at rest in 22 (36.7%) patients and exercise-induced defects in 8 (13.3%), whereas MDCT revealed coronary calcifications in 15 subjects (25%). Coronary calcium deposits increased after 1 year in the placebo group (plaque volume change from 35.2 ± 44.9 to 62.9 ± 72.4, P < 0.05; calcium score from 32.1 ± 39.1 to 59.5 ± 64.4; P < 0.05), but not in the atorvastatin group (plaque volume 54.5 ± 62.4 vs. 51.0 ± 47.6, P not significant; calcium score 44.8 ± 50.6 vs. 54.9 ± 62.5, P not significant). The atorvastatin group showed a decrease in total serum cholesterol (from 5.1 ± 1.2 to 4.4 ± 0.7 mmol/L, P < 0.05), LDL cholesterol (2.9 ± 1.0 to 2.3 ± 0.6 mmol/L, P < 0.05), triglycerides (1.6 ± 0.6 to 1.2 ± 0.5 mmol/L, P < 0.05), and C-reactive protein (CRP) (4.4 ± 4.1 to 2.7 ± 1.7 mg/L, P < 0.05). There was no change in the mean Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score in patients from both groups. Perfusion defects observed at randomization showed no change after one year treatment with atorvastatin. In SLE patients 40 mg of atorvastatin daily for 1 year led to a decrease in

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

    PubMed

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

    2013-07-05

    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.

  5. Intervertebral disc calcifications in children.

    PubMed

    Beluffi, G; Fiori, P; Sileo, C

    2009-03-01

    This study was done to assess the presence of both asymptomatic and symptomatic intervertebral disc calcifications in a large paediatric population. We retrospectively reviewed the radiographs taken during the past 26 years in children (age 0-18 years) undergoing imaging of the spine or of other body segments in which the spine was adequately depicted, to determine possible intervertebral disc calcifications. The following clinical evaluation was extrapolated from the patients' charts: presence of spinal symptoms, history of trauma, suspected or clinically evident scoliosis, suspected or clinically evident syndromes, bone dysplasias, and pre- or postoperative chest or abdominal X-rays. We detected intervertebral disc calcifications in six patients only. Five calcifications were asymptomatic (one newborn baby with Patau syndrome; three patients studied to rule out scoliosis, hypochondroplasia and syndromic traits; one for dyspnoea due to sunflower seeds inhalation). Only one was symptomatic, with acute neck pain. Calcifications varied in number from one in one patient to two to five in the others. Apart from the calcification in the patient with cervical pain, all calcifications were asymptomatic and constituted an incidental finding (particularly those detected at the thoracic level in the patient studied for sunflower-seed inhalation). Calcification shapes were either linear or round. Our series confirms that intervertebral disc calcifications are a rare finding in childhood and should not be a source of concern: symptomatic calcifications tend to regress spontaneously within a short time with or without therapy and immobilisation, whereas asymptomatic calcifications may last for years but disappear before the age of 20 years. Only very few cases, such as those of medullary compression or severe dysphagia due to anterior herniation of cervical discs, may require surgical procedures.

  6. Vascular Calcification: Mechanisms of Vascular Smooth Muscle Cell Calcification

    PubMed Central

    Leopold, Jane A.

    2014-01-01

    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. PMID:25435520

  7. Arterial calcification: A new perspective?

    PubMed

    Nicoll, R; Henein, M

    2017-02-01

    Arterial calcification is commonly seen in atherosclerosis, chronic kidney disease (CKD) and diabetes and has long been considered a natural progression of atherosclerosis. Yet it is a systemic condition, occurring in a wide and diverse range of disease states and no medical treatment for cardiovascular disease has yet found a way to regress it; on the contrary, lipid-lowering therapy may worsen its progression. Although numerous studies have found associations between calcification and biomarkers, none has yet found a unifying mechanism that explains the calcification found in atherosclerosis, CKD or diabetes and many of the biomarkers are equally associated with atheroma development and cardiovascular events. Furthermore, both presence and absence of coronary artery calcification appear predictive of plaque rupture and cardiovascular events, indicating that the association is not causal. This suggests that we are no further forward in understanding the true nature of arterial calcification or its pathogenesis, other than noting that it is 'multifactorial'. This is because most researchers view arterial calcification as a progressive pathological condition which must be treated. Instead, we hypothesise that calcification develops as an immune response to endothelial injury, such as shear stress or oxidative stress in diabetics, and is consequently part of the body's natural defences. This would explain why it has been found to be protective of plaque rupture and why it is unresponsive to lipid-lowering agents. We propose that instead of attempting to treat arterial calcification, we should instead be attempting to prevent or treat all causes of endothelial injury.

  8. Renal osteodystrophy and vascular calcification.

    PubMed

    Arcidiacono, T; Paloschi, V; Rainone, F; Terranegra, A; Dogliotti, E; Aloia, A; Soldati, L; Vezzoli, G

    2009-01-01

    Chronic kidney disease (CKD) is characterized by phosphate retention and reduced synthesis of 1.25(OH)2-vitamin D stimulating parathyroid hyperplasia. These changes cause a complex osteopathy, defined as renal osteodystrophy, and vascular calcification. Renal osteodystrophy increases the risk of fracture and causes deformities and disability. Vascular calcification occurs in a large proportion of hemodialysis patients and is a marker of arteriopathy. Calcifying arteriopathy induces arterial stiffness and contributes to the high cardiovascular mortality and morbidity among CKD patients. Vascular calcification results from a process of local bone formation induced by osteoblast-like cells developing in the vascular wall from resident cells. Osteoblast differentiation of resident vascular cells may be mediated by metabolic factors and may be induced by high concentrations of phosphate. Therefore, phosphate retention appears as the most detrimental factor affecting arteries in CKD patients. There is no specific therapy to revert soft tissue calcification, but calcification must be prevented in the early stages of CKD.

  9. [Calcification in nonfunctioning transplanted kidneys].

    PubMed

    Peces, R; Sánchez, R J; Fernández, E J; Peces, C

    2007-01-01

    Failed renal allografts often are left in situ in patients who revert to chronic dialysis therapy or who undergo retransplantation. These organs may be the site of massive calcification despite their lack of physiological function. Calcification of an endstage renal allograft is sometimes found incidentally. We report here two patients who developed extensive calcification of the renal graft, one was on chronic hemodialysis and the other had a second renal transplantation with normal renal function. The precise pathogenesis of calcification and the factors which determine its tissue localization are unclear. Factors postulated to promote the development of metastatic calcification include an elevated calcium phosphate product, severe secondary hyperparathyroidism, aluminium toxicity and duration of dialytic therapy. In some cases local factors related with the chronic inflammatory rejection process are probably involved as well. However, the exact relative contribution of these factors remains unresolved. Unless specific clinical indications are present, transplant nephrectomy is not necessary for calcified end-stage renal allografts.

  10. 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

  11. 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.

  12. 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.

  13. [Animal models for vascular calcification].

    PubMed

    Ikeda, Koji; Nakagawa, Yusuke; Matsubara, Hiroaki

    2010-11-01

    Analysis of animal models is indispensable to elucidate the molecular mechanism in vascular calcification (VC) as well as to develop new therapies for VC. Various gene-modified mice that show VC have been reported, and considerable progress has been made through the analyses of these animals. Mice of which bone-calcification regulatory factors were modified are the representative animal models for VC, indicating that these factors certainly regulate VC as well as bone-calcification. Inducible VC in wild-type animals is also an important research tool for developing preventive and therapeutic approach for VC.

  14. [Eight cases of calcific retropharyngeal tendinitis/retropharyngeal calcific tendinitis].

    PubMed

    Ohtsuka, Yuichiro; Chazono, Hideaki; Suzuki, Homare; Ohkuma, Yusuke; Sakurai, Toshioki; Hanazawa, Toyoyuki; Okamoto, Yoshitaka

    2013-11-01

    Calcific retropharyngeal tendinitis/retropharyngeal calcific tendinitis is an inflammation of the longus colli muscle caused by calcium hydroxyapatite crystal depositon in the longus colli muscle tendon. The three major symptoms are neck pain, limitations of neck movement, and swallowing pain. We treated 8 cases of calcific retropharyngeal tendinitis/ retropharyngeal calcific tendinitis. Each patient complained of neck pain, limitations of neck movement, and swallowing pain. The only local finding was the smooth swelling of the posterior pharyngeal wall. CT imaging showed calcification of the tendon of the longus colli muscle and a low density area in the retropharyngeal space without ring enhancement, suggesting a retropharyngeal abscess. MR imaging showed the smooth swelling of the retropharyngeal space and an increased signal intensity on T2-weighted MR imaging. Calcific retropharyngeal tendinitis heals spontaneously, and treatment is not usually required. However, the clinical outcomes are similar and can be confused with retropharyngeal abscess and pyogenic spondylitis, so antibiotics are administrated in many cases. In our report, 7 patients were hospitalized and were treated with the intravenous administration of antibiotics, while 1 patient who refused hospitalization was treated with an oral antibiotic. Steroids were administrated in 2 cases. The 7 patients who were hospitalized were cured within 6 to 10 days.

  15. The vascular biology of calcification.

    PubMed

    Shroff, Rukshana C; Shanahan, Catherine M

    2007-01-01

    Vascular calcification is an active, cell-mediated process that results from an imbalance between the promoters and inhibitors of mineralization. The process of vascular calcification shares many similarities with that of skeletal mineralization. However, while skeletal mineralization is a regulated process induced by complex, well-timed developmental cues, vascular calcification is a pathological process, occurring in response to dysregulated/inappropriate environmental cues. Damage inducing agents present in the uremic milieu such as a mineral imbalance, induce vascular smooth muscle cell (VSMC) apoptosis, and vesicle release resulting in mineral nucleation and the deposition of hydroxyapatite. Under normal conditions, inhibitors of soft-tissue mineralization such as matrix gamma-carboxyglutamic acid protein are expressed locally within the vessel wall while others such as fetuin-A are present in the circulation. Down-regulation or perturbation of these proteins leads to a phenotypic transformation of VSMC into osteo/chondrocytic-like cells that have the capacity to modulate the mineralization process. Many aspects of the mechanisms underlying vascular calcification have been defined through in vitro studies and molecular biological techniques; however, there are still unanswered questions, particularly with respect to the relationship between bone and vascular calcification, processes that appear to be inversely related. A better understanding of the complex mechanisms regulating tissue calcification may have therapeutic potential in reducing the cardiovascular disease-associated morbidity and mortality in patients with renal disease.

  16. Calcification Changes of Mesozoic Calcareous Nannofossils

    NASA Astrophysics Data System (ADS)

    Bornemann, A.; Mutterlose, J.

    2003-12-01

    Studies on plankton samples and cultures revealed a variety factors which presumably control calcification and the size of coccoliths. Among others temperature, nutrients and seawater pH are thought to influence nannoplankton calcification. Whereas these studies only provide information of very short time intervals from hours to years, global climatic and oceanographic changes occur, however, on geological timescales. Thus their impact on nannofossil calcification and carbonate production can only be studied from the fossil record. We investigated DSDP sites from the western Atlantic of late Jurassic to early Cretaceous age in order to better understand long-term variations of the size of common nannofossil taxa and the resulting carbonate accumulation. The studied interval is characterized by two events in the pelagic carbonate record: (1) the onset of pelagic carbonate accumulation in the Tithonian, and (2) the Valanginian 'nannoconid crisis'. The Tithonian event went along with high abundances of strongly calcified nannofossils which presumably have an affinity to more oligotrophic surface water conditions. The mid Valanginian is marked by a positive carbon isotope excursion (CIE). This coincides with a sea level rise, volcanic activity and elevated atmospheric pCO2 levels. Greenhouse climate and an accelerated hydrological cycle presumably intensified weathering processes causing enhanced nutrient transfer from the continents into the oceans. Increasing surface water fertility is indicated by high abundances of nannofossils which possibly indicate more eutrophic conditions. In the western Tethys the CIE is predated by a sharp decrease in the abundance of rockforming nannoconids. This event is less pronounced in the western Atlantic due to a general scarcity of nannoconids. Low nannofossil carbonate accumulation rates and a dominance of less calcified taxa were observed and may reflect a general marine biocalcification crisis. Possible factors, which may have

  17. 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.

  18. 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.

  19. 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.

  20. Genetic predisposition to calcific aortic stenosis and mitral annular calcification.

    PubMed

    Kutikhin, Anton G; Yuzhalin, Arseniy E; Brusina, Elena B; Ponasenko, Anastasia V; Golovkin, Alexey S; Barbarash, Olga L

    2014-09-01

    Valvular calcification precedes the development of valvular stenosis and may represent an important early phenotype for valvular heart disease. It is known that development of valvular calcification is likely to occur among members of a family. However, the knowledge about the role of genomic predictive markers in valvular calcification is still elusive. Aims of this review are to assess the impact of gene polymorphisms on risk and severity of aortic stenosis and mitral annular calcification. According to the results of the investigations carried out, all polymorphisms may be divided into the three groups conferring the level of evidence of their association with valvular stenosis. It is possible to conclude that apoB (XbaI, rs1042031, and rs6725189), ACE (rs4340), IL10 (rs1800896 and rs1800872), and LPA (rs10455872) gene polymorphisms may be associated with valvular calcific stenosis with a relatively high level of evidence. A number of other polymorphisms, such as PvuII polymorphism within the ORα gene, rs1042636 polymorphism within the CaSR gene, rs3024491, rs3021094, rs1554286, and rs3024498 polymorphisms within the IL10 gene, rs662 polymorphism within the PON1 gene, rs2276288 polymorphism within the MYO7A gene, rs5194 polymorphism within the AGTR1 gene, rs2071307 polymorphism within the ELN gene, rs17659543 and rs13415097 polymorphisms within the IL1F9 gene may correlate with a risk of calcific valve stenosis with moderate level of evidence. Finally, rs1544410 polymorphism within the VDR gene, E2 and E4 alleles within the apoE gene, rs6254 polymorphism within the PTH gene, and rs1800871 polymorphism within the IL10 gene may be associated with aortic stenosis with low level of evidence.

  1. 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.

  2. Reduced calcification decreases photoprotective capability in the coccolithophorid Emiliania huxleyi.

    PubMed

    Xu, Kai; Gao, Kunshan

    2012-07-01

    Intracellular calcification of coccolithophores generates CO₂ and consumes additional energy for acquisition of calcium and bicarbonate ions; therefore, it may correlate with photoprotective processes by influencing the energetics. To address this hypothesis, a calcifying Emiliania huxleyi strain (CS-369) was grown semi-continuously at reduced (0.1 mM, LCa) and ambient Ca²⁺ concentrations (10 mM, HCa) for 150 d (>200 generations). The HCa-grown cells had higher photosynthetic and calcification rates and higher contents of Chl a and carotenoids compared with the naked (bearing no coccoliths) LCa-grown cells. When exposed to stressfull levels of photosynthetically active radiation (PAR), LCa-grown cells displayed lower photochemical yield and less efficient non-photochemical quenching (NPQ). When the LCa- or HCa-grown cells were inversely shifted to their counterpart medium, LCa to HCa transfer increased photosynthetic carbon fixation (P), calcification rate (C), the C/P ratio, NPQ and pigment contents, whereas those shifted from HCa to LCa exhibited the opposite effects. Increased NPQ, carotenoids and quantum yield were clearly linked with increased or sustained calcification in E. huxleyi. The calcification must have played a role in dissipating excessive energy or as an additional drainage of electrons absorbed by the photosynthetic antennae. This phenomenon was further supported by testing two non-calcifying strains, which showed insignificant changes in photosynthetic carbon fixation and NPQ when transferred to LCa conditions.

  3. 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%).

  4. Reduction of calcification by various treatments in cardiac valves.

    PubMed

    Rao, K P; Shanthi, C

    1999-01-01

    The importance of glutaraldehyde pretreated bioprosthetic heart valves fabricated from bovine pericardium or porcine aortic valves is well realized in the management of valvular heart diseases. But, calcification limits the durability and is the most frequent cause of failure of these bioprosthetic heart valves. Various research groups in the world are actively involved in describing, understanding, and preventing calcification of bioprosthetic heart valves. Since there is no satisfactory clinical means for preventing or treating this disorder, attempts are made to improve the anticalcification properties of the replacement valves in the preparation stage itself. Research in this area is very active, and many newer approaches are made to mitigate the problem. An attempt has been made in the present article to review various theories put forward to explain the causative factors involved and mechanistic aspects of biocalcification and to present various strategies attempted for the prevention of calcification with the special feature on the work done in the area in our laboratory.

  5. Pontine calcification following radiotherapy: CT demonstration.

    PubMed

    Price, D B; Hotson, G C; Loh, J P

    1988-01-01

    Development of pontine calcifications following radiation therapy for suprasellar tumors is described in two patients, 5 and 9 years old. Post-radiotherapy brain calcifications are rare in the brain stem.

  6. [Calcific tendinitis of the shoulder].

    PubMed

    Diehl, P; Gerdesmeyer, L; Gollwitzer, H; Sauer, W; Tischer, T

    2011-08-01

    Calcific tendinitis of the shoulder is a process involving crystal calcium deposition in the rotator cuff tendons, which mainly affects patients between 30 and 50 years of age. The etiology is still a matter of dispute. The diagnosis is made by history and physical examination with specific attention to radiologic and sonographic evidence of calcific deposits. Patients usually describe specific radiation of the pain to the lateral proximal forearm, with tenderness even at rest and during the night. Nonoperative management including rest, nonsteroidal anti-inflammatory drugs, subacromial corticosteroid injections, and shock wave therapy is still the treatment of choice. Nonoperative treatment is successful in up to 90% of patients. When nonsurgical measures fail, surgical removal of the calcific deposit may be indicated. Arthroscopic treatment provides excellent results in more than 90% of patients. The recovery process is very time consuming and may take up to several months in some cases.

  7. Spatial and Seasonal Calcification in Corals and Calcareous Crusts in a Naturally Warm Coral Reef Region

    NASA Astrophysics Data System (ADS)

    Roik, A.; Roder, C.; Roethig, T.; Voolstra, C. R.

    2016-02-01

    The Red Sea harbors highly diverse and structurally complex coral reefs and is of interest for ocean warming studies. In the central and southern part, water temperatures rise above 30°C during summer, constituting one of the warmest coral reef environments worldwide. Additionally, seasonal variability of temperatures allows studying changes of environmental conditions and their effects on coral reef processes. To explore the influence of these warm and seasonally variable habitats on reef calcification, we measured in situ calcification of primary and secondary reef-builders in the central Red Sea. We collected calcification rates on the major habitat-forming coral genera Porites, Acropora, and Pocillopora, and also on calcareous crusts (CC). The study comprised forereef and backreef environments of three reefs along a cross-shelf gradient assessed over four seasons of the year. Calcification patterns of all coral genera were consistent across the shelf and highest in spring. In contrast to the corals, CC calcification strongly increased with distance from shore, but varied to a lesser extend over the seasons demonstrating lower calcification rates during spring and summer. Interestingly, reef calcification rates in the central Red Sea were on average in the range of data reported from the Caribbean and Indo-Pacific. For Acropora, annual average calcification rates were even at the lower end in comparison to studies from other locations. While coral calcification maxima typically have been observed during summer in many reef locations worldwide, we observed calcification maxima during spring in the central Red Sea indicating that summer temperatures may exceed the optima of reef calcifiers. Our study provides a baseline of calcification data for the region and serves as a foundation for comparative efforts to quantify the impact of future environmental change.

  8. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Mechanisms of vascular calcification].

    PubMed

    Shioi, Atsushi

    2015-05-01

    Vascular calcification is an independent risk factor for the development of cardiovascular disease and is classified into two types based on the site of calcification : intimal atherosclerotic calcification and Mönckeberg's medial calcification. Matrix vesicles released from macrophages and vascular smooth muscle cells (VSMC) during apoptosis play a pivotal role in formation of fine granular calcification, while osteogenic differentiation of VSMC contributes to progression of advanced calcification. Recent noninvasive imaging studies of atherosclerotic calcification provide robust evidence that inflammation precedes active calcification, leading to establish the inflammation-dependent calcification paradigm. On the other hand, elastin degradation by increased elastolytic activities and disturbance of regulatory systems of extracellular pyrophosphate metabolism play an important role in development of Mönckeberg's medial calcification.

  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. Intracranial calcification in central diabetes insipidus.

    PubMed

    Al-Kandari, Salwa Ramadan; Pandey, Tarun; Badawi, Mona H

    2008-01-01

    Intracranial calcification is a known but extremely rare complication of diabetes insipidus. To date, only 16 patients have been reported and all had the peripheral (nephrogenic) type of diabetes insipidus. We report a child with intracranial calcification complicating central diabetes insipidus. We also report a child with nephrogenic diabetes insipidus, and compare the patterns of intracranial calcification.

  11. Chronic calcific tendinitis of the neck

    SciTech Connect

    Newmark, H.; Zee, C.S.; Frankel, P.; Robinson, A.; Blau, L.; Gans, D.C.

    1981-12-01

    The authors present the first three cases of chronic calcific tendinits of the neck. This condition is diagnosed radiologically by the presence of calcification located just inferior to the anterior tubercle of C1. The calcification is at the insertion of the longus colli muscle. No soft tissue swelling is present and the patients are asymptomatic.

  12. MR appearance of pulmonary metastatic calcification

    SciTech Connect

    Taguchi, Yasushi; Fuyuno, Gentaro; Shioya, Sumie; Yanagimachi, Noriharu; Katoh, Hirokazu; Matsuyama, Seiya; Ohta, Yasuyo

    1996-01-01

    We report a case of metastatic pulmonary calcification that showed hyperintense signal on T1-weighted MRI. This uncommon MR appearance of calcification is similar to the MR characteristics of calcification in the brain due to abnormal calcium metabolism. 11 refs., 5 figs.

  13. Calcification of intraocular hydrogel lens: evidence of dystrophic calcification.

    PubMed

    Yong, Jim L C; Lertsumitkul, Somsak; Killingsworth, Murray C; Filipic, Marijan

    2004-10-01

    To report and describe the surface calcification of three cases of implanted intraocular hydrogel lens. Three surgically extracted hydrogel intraocular lenses were studied by light and transmission electron microscopy as well as by energy dispersion X-ray microanalysis. The lens surfaces were covered by granular deposits of calcium phosphate, clearly delineated by von Kossa and alizarin stains for calcium. Transmission electron microscopy showed the deposits to be located within the superficial lens material to a depth of 7 microm and to be associated with what appear to be traces of cellular material including basement membrane and plasmalemma. To the authors' knowledge there has been only one other transmission electron microscopic study. Energy dispersion X-ray microanalysis showed the deposits to contain calcium and phosphorous in all cases. This study confirms and extends the previous reports of five cases of calcification of hydrogel intraocular lenses. The exact mechanism of calcification remains obscure but evidence suggesting cell-mediated dystrophic calcification of the lens surface is presented. Further study is required to monitor the incidence and development of this phenomenon.

  14. Classification of the micromorphology of breast calcifications in x-ray dark-field mammography

    NASA Astrophysics Data System (ADS)

    Willer, Konstantin; Scherer, Kai; Braig, Eva; Ehn, Sebastian; Schock, Jonathan; Wolf, Johannes; Birnbacher, Lorenz; Chabior, Michael; Mayr, Doris; Grandl, Susanne; Sztrókay-Gaul, Aniko; Hellerhof, Karin; Reiser, Maximilian; Pfeiffer, Franz; Herzen, Julia

    2017-03-01

    The distant goal of this investigation is to reduce the number of invasive procedures associated with breast micro calcification biopsies, by improving and refining conventional BIRADS micro calcification assessments with x-ray dark-field mammography. The study was institutional review board (IRB) approved. A dedicated grating-based radiography setup (Mo-target, 40 keV, 70 mA) was used to investigate one breast mastectomy and 31 biopsies with dark-field mammography. Comparing the absorption and scattering properties of micro calcifications clusters enables accessing information on the interior morphology on the micron-scale retrieved in a non-invasive manner. Insights underlying the micro morphological nature of breast calcifications were verified by comprehensive high-resolution micro-CT measurements. It was found that Dark-field mammography allows a micro-structural classification of breast micro calcification as ultra-fine, fine, pleomorphic and coarse textured using conventional detectors. Dark-field mammography is thereby highly sensitive to minor structural deviations. Finally, the determined micro-texture of the investigated micro calcifications was correlated with findings obtained from histopathological work up. The presented results demonstrate that dark-field mammography yields the potential to enhance diagnostic validity of current micro calcification analysis - which is yet limited to the exterior appearance of micro calcification clusters - and thereby reduce the number of invasive procedures.

  15. 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.

  16. Vascular calcification in chronic kidney disease.

    PubMed

    Jono, Shuichi; Shioi, Atsushi; Ikari, Yuji; Nishizawa, Yoshiki

    2006-01-01

    Vascular calcification is often encountered in advanced atherosclerotic lesions and is a common consequence of aging. Calcification of the coronary arteries has been positively correlated with coronary atherosclerotic plaque burden, increased risk of myocardial infarction, and plaque instability. Chronic kidney disease (CKD) patients have two to five times more coronary artery calcification than healthy age-matched individuals. Vascular calcification is a strong prognostic marker of cardiovascular disease mortality in CKD patients. Vascular calcification has long been considered to be a passive, degenerative, and end-stage process of atherosclerosis and inflammation. However, recent evidence indicates that bone matrix proteins such as osteopontin, matrix Gla protein (MGP), and osteocalcin are expressed in calcified atherosclerotic lesions, and that calcium-regulating hormones such as vitamin D3 and parathyroid hormone-related protein regulate vascular calcification in in vitro vascular calcification models based on cultured aortic smooth muscle cells. These findings suggest that vascular calcification is an actively regulated process similar to osteogenesis, and that bone-associated proteins may be involved in the development of vascular calcification. The pathogenesis of vascular calcification in CKD is not well understood and is almost multifactorial. In CKD patients, several studies have found associations of both traditional risk factors, such as hypertension, hyperlipidemia, and diabetes, and uremic-specific risk factors with vascular calcification. Most patients with progressive CKD develop hyperphosphatemia. An elevated phosphate level is an important risk factor for the development of calcification and cardiovascular mortality in CKD patients. Thus, it is hypothesized that an important regulator of vascular calcification is the level of inorganic phosphate. In order to test this hypothesis, we characterized the response of human smooth muscle cell (HSMC

  17. [Molecular mechanisms of bone calcification].

    PubMed

    Hoshi, Kazuto; Ozawa, Hidehiro

    2003-04-01

    Bone matrix consists mainly of hydroxyapatite and organics. The latter include various substances which interact with minerals. Osteoblasts secrete these organic substances and control crystal formation and growth of hydroxyapatite. The authors discuss the molecular mechanisms of calcification by focusing on the mineral/organic interaction.

  18. Effect of calcification on the mechanical stability of plaque based on a three-dimensional carotid bifurcation model

    PubMed Central

    2012-01-01

    Background This study characterizes the distribution and components of plaque structure by presenting a three-dimensional blood-vessel modelling with the aim of determining mechanical properties due to the effect of lipid core and calcification within a plaque. Numerical simulation has been used to answer how cap thickness and calcium distribution in lipids influence the biomechanical stress on the plaque. Method Modelling atherosclerotic plaque based on structural analysis confirms the rationale for plaque mechanical examination and the feasibility of our simulation model. Meaningful validation of predictions from modelled atherosclerotic plaque model typically requires examination of bona fide atherosclerotic lesions. To analyze a more accurate plaque rupture, fluid-structure interaction is applied to three-dimensional blood-vessel carotid bifurcation modelling. A patient-specific pressure variation is applied onto the plaque to influence its vulnerability. Results Modelling of the human atherosclerotic artery with varying degrees of lipid core elasticity, fibrous cap thickness and calcification gap, which is defined as the distance between the fibrous cap and calcification agglomerate, form the basis of our rupture analysis. Finite element analysis shows that the calcification gap should be conservatively smaller than its threshold to maintain plaque stability. The results add new mechanistic insights and methodologically sound data to investigate plaque rupture mechanics. Conclusion Structural analysis using a three-dimensional calcified model represents a more realistic simulation of late-stage atherosclerotic plaque. We also demonstrate that increases of calcium content that is coupled with a decrease in lipid core volume can stabilize plaque structurally. PMID:22336469

  19. Role of circulating osteogenic progenitor cells in calcific aortic stenosis.

    PubMed

    Gössl, Mario; Khosla, Sundeep; Zhang, Xin; Higano, Nara; Jordan, Kyra L; Loeffler, Darrell; Enriquez-Sarano, Maurice; Lennon, Ryan J; McGregor, Ulrike; Lerman, Lilach O; Lerman, Amir

    2012-11-06

    The purpose of this study was to determine the role of circulating endothelial progenitor cells with osteoblastic phenotype (EPC-OCN) in human aortic valve calcification (AVC). Recent evidence suggests that rather than passive mineralization, AVC is an active atherosclerotic process with an osteoblastic component resembling coronary calcification. We have recently identified circulating EPCs with osteogenic properties carrying both endothelial progenitor (CD34, KDR) and osteoblastic (osteocalcin [OCN]) cell surface markers. Blood samples from controls (n = 22) and patients with mild to moderate calcific aortic stenosis (mi-moAS, n = 17), severe calcific AS (sAS, n = 26), and both sAS and severe coronary artery disease (sCAD) (n = 33) were collected during diagnostic coronary angiography. By using flow cytometry, peripheral blood mononuclear cells were analyzed for CD34, KDR, and OCN. Resected normal and calcified aortic valves were analyzed histologically. Patients with mi-moAS and patients with sAS/sCAD had significantly less EPCs (CD34+/KDR+/OCN-) than controls. Patients with sAS showed significantly higher numbers of EPC-OCN (CD34+/KDR+/OCN+) than controls. In addition, the percentage of EPC costaining for OCN was higher in all disease groups compared with controls. A subgroup analysis of younger patients with bicuspid sAS showed a similar pattern of significantly lower EPCs but a high percentage of coexpression of OCN. Immunofluorescence showed colocalization of nuclear factor kappa-B and OCN in diseased and normal valves. CD34+/OCN+ cells were abundant in the endothelial and deeper cell layers of calcific aortic valve tissue but not in normal aortic valve tissue. Circulating EPC-OCN may play a significant role in the pathogenesis and as markers of prognostication of calcific AS. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  20. Gla-rich protein is a novel vitamin K-dependent protein present in serum that accumulates at sites of pathological calcifications.

    PubMed

    Viegas, Carla S B; Cavaco, Sofia; Neves, Pedro L; Ferreira, Ana; João, Alexandre; Williamson, Matthew K; Price, Paul A; Cancela, M Leonor; Simes, Dina C

    2009-12-01

    Mineralization of soft tissues is an abnormal process that occurs in any body tissue and can greatly increase morbidity and mortality. Vitamin K-dependent (VKD) proteins play a crucial role in these processes; matrix Gla protein is considered one of the most relevant physiological inhibitors of soft tissue calcification know to date. Several studies have suggested that other, still unknown, VKD proteins might also be involved in soft tissue calcification pathologies. We have recently identified in sturgeon a new VKD protein, Gla-rich protein (GRP), which contains the highest ratio between number of Gla residues and size of the mature protein so far identified. Although mainly expressed in cartilaginous tissues of sturgeon, in rat GRP is present in both cartilage and bone. We now show that GRP is a circulating protein that is also expressed and accumulated in soft tissues of rats and humans, including the skin and vascular system in which, when affected by pathological calcifications, GRP accumulates at high levels at sites of mineral deposition, indicating an association with calcification processes. The high number of Gla residues and consequent mineral binding affinity properties strongly suggest that GRP may directly influence mineral formation, thereby playing a role in processes involving connective tissue mineralization.

  1. Visualizing novel concepts of cardiovascular calcification.

    PubMed

    Hjortnaes, Jesper; New, Sophie E P; Aikawa, Elena

    2013-04-01

    Cardiovascular calcification is currently viewed as an active disease process similar to embryonic bone formation. Cardiovascular calcification mainly affects the aortic valve and arteries and is associated with increased mortality risk. Aortic valve and arterial calcification share similar risk factors, including age, gender, diabetes, chronic renal disease, and smoking. However, the exact cellular and molecular mechanism of cardiovascular calcification is unknown. Late-stage cardiovascular calcification can be visualized with conventional imaging modalities such as echocardiography and computed tomography. However, these modalities are limited in their ability to detect the development of early calcification and the progression of calcification until advanced tissue mineralization is apparent. Due to the subsequent late diagnosis of cardiovascular calcification, treatment is usually comprised of invasive interventions such as surgery. The need to understand the process of calcification is therefore warranted and requires new imaging modalities which are able to visualize early cardiovascular calcification. This review focuses on the use of new imaging techniques to visualize novel concepts of cardiovascular calcification. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Influence of surface structure on thermoprotection properties of intumescent systems

    NASA Astrophysics Data System (ADS)

    Reshetnikov, Igor S.; Yablokova, Marina Yu.; Khalturinskij, Nikolay A.

    1997-06-01

    Intumescent fire retardant coatings have found great application due to high thermoprotection properties, which reduce heat flow on the polymer surface. However there were no attempts to study the influence of surface structure on foamed char formation processes. In this work we present the experimental investigation of thermoprotection properties of CFR with a PTFE modified surface.

  3. Smoking and morphology of calcific deposits affect the outcome of needle aspiration of calcific deposits (NACD) for calcific tendinitis of the rotator cuff.

    PubMed

    Oudelaar, Bart W; Ooms, Edwin M; Huis In 't Veld, Rianne M H A; Schepers-Bok, Relinde; Vochteloo, Anne J

    2015-11-01

    Although NACD has proven to be an effective minimal invasive treatment for calcific tendinitis of the rotator cuff, little is known about the factors associated with treatment failure or the need for multiple procedures. Patients with symptomatic calcific tendinitis who were treated by NACD were evaluated in a retrospective cohort study. Demographic details, medical history, sonographic and radiographic findings were collected from patient files. Failure of NACD was defined as the persistence of symptoms after a follow-up of at least six months. NACD procedures performed within six months after a previous NACD procedure were considered repeated procedures. Multivariate logistic regression analysis was used to determine factors associated with treatment failure and multiple procedures. 431 patients (277 female; mean age 51.4±9.9 years) were included. Smoking (adjusted odds ratio (AOR): 1.7, 95% CI 1.0-2.7, p=0.04) was significantly associated with failure of NACD. Patients with Gärtner and Heyer (GH) type I calcific deposits were more likely to need multiple NACD procedures (AOR: 3.4, 95% CI 1.6-7.5, p<0.01) compared to patients with type III calcific deposits. Partial thickness rotator cuff tears were of no influence on the outcome of NACD or the number of treatments necessary. Smoking almost doubled the chance of failure of NACD and the presence of GH type I calcific deposits significantly increased the chance of multiple procedures. Partial thickness rotator cuff tears did not seem to affect the outcome of NACD. Based on the findings in this study, the importance of quitting smoking should be emphasized prior to NACD and partial thickness rotator cuff tears should not be a reason to withhold patients NACD. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. 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.

  5. 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.

  6. Vascular calcification in chronic kidney disease: Pathogenesis and clinical implication.

    PubMed

    Disthabanchong, Sinee

    2012-04-06

    Cardiovascular disease is the leading cause of death among patients with chronic kidney disease (CKD). Vascular calcification (VC) is one of the independent risk factors associated with cardiovascular disease and cardiovascular mortality in both the general population and CKD patients. Earlier evidence revealed substantially higher prevalence of VC in young adults on chronic hemodialysis compared to the general population in the same age range, indicating the influence of CKD-related risk factors on the development of VC. Pathogenesis of VC involves an active, highly organized cellular transformation of vascular smooth muscle cells to bone forming cells evidenced by the presence of bone matrix proteins in the calcified arterial wall. VC occurs in both the intima and the media of arterial wall with medial calcification being more prevalent in CKD. In addition to traditional cardiovascular risks, risk factors specific to CKD such as phosphate retention, excess of calcium, history of dialysis, active vitamin D therapy in high doses and deficiency of calcification inhibitors play important roles in promoting the development of VC. Non-contrast multi-slice computed tomography has often been used to detect coronary artery calcification. Simple plain radiographs of the lateral lumbar spine and pelvis can also detect VC in the abdominal aorta and femoral and iliac arteries. Currently, there is no specific therapy to reverse VC. Reduction of calcium load, lowering phosphate retention using non-calcium containing phosphate binders, and moderate doses of active vitamin D may attenuate progression. Parenteral sodium thiosulfate has also been shown to delay VC progression.

  7. 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.

  8. 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.

  9. 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.

  10. Deficiencies of physiologic calcification inhibitors and low-grade inflammation in arterial calcification: lessons for cartilage calcification.

    PubMed

    Rutsch, Frank; Terkeltaub, Robert

    2005-03-01

    Apart from clinical parallels, similarities in the pathogenesis of arterial and articular cartilage calcification have come to light in recent years. These include the roles of aging, of chronic low-grade inflammation and of genetic and acquired dysregulation of inorganic pyrophosphate (PP(i)) metabolism. This review focuses on recent developments in understanding the pathogenesis of artery calcification pertinent to interpretation of the mechanistic basis for articular cartilage calcification in aging and osteoarthritis.

  11. Atypical Steatocystoma Multiplex with Calcification

    PubMed Central

    Rahman, Muhammad Hasibur; Islam, Muhammad Saiful; Ansari, Nazma Parvin

    2011-01-01

    A 60-year-old male reported to us with an atypical case of giant steatocystoma multiplex in the scrotum with calcification. There was no family history of similar lesions. Yellowish, creamy material was expressed from a nodule during punch biopsy. The diagnosis was based on clinical as well as histological findings. Successful surgical excision was done to cure the case without any complications. PMID:22363850

  12. 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. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  13. [Differential diagnosis of intrasinusal calcifications].

    PubMed

    Hernández Montero, E; Martínez Berganza, R; Carmen Sampériz, L

    2004-01-01

    We present a case of a patient with a sinusitis of three months evolution. The CT scan showed an occupation of the middle meatus of the left nasal fossa with alergic polyps and a total opacification of the left maxillary sinus with calcifications, that makes to discard the metalic on dental nature of an intrasinusal body, and other chronic granulomatous processes. The correct surgical restauration of the osteomeotal complex obtained the complete resolution of the process.

  14. Influence of Superhydrophobic Properties on Deicing

    NASA Astrophysics Data System (ADS)

    Nazhipkyzy, M.; Mansurov, Z. A.; Amirfazli, A.; Esbosin, A.; Temirgaliyeva, T. S.; Lesbayev, B. T.; Aliyev, E. T.; Prikhodko, N. G.

    2016-11-01

    Nowadays the creation of anti-icing, or deicing, surfaces is one of the most important problems, as such surfaces are widely used in aeronautics, wind turbines, and telecommunication antennas. In this paper, we focus mainly on reducing the ice adhesion forces and easy ice removal, once ice has formed. Removal of a liquid from a surface can be provided by modification of the surface wettability by means of applying superhydrophobic coatings. Such coatings are water-resistant, i.e., are characterized by low water adhesion forces. To study the impact of superhydrophobic coatings, tests were performed on the surface of a wing in a wind tunnel. By spraying Teflon and polyphenylene sulfide (PPS) on the wing, we obtained a superhydrophobic film. This film has a structure that provides superhydrophobic properties, so that the wetting angle is above 140°. A comparison of the resulting surface with a clean Teflon one shows that adhesion of the Teflon + PPS mixture to an aluminum surface is five times higher. We also investigate the degree of ice formation on the surfaces of simple and superhydrophobic aircraft wings at a temperature of -18°C. It was shown that ice was formed on a simple wing within 40 s and on a superhydrophobic wing within 25 s. When the simple wing with a mass of 23 g was inserted into the wind tunnel, its mass reached 50 g, and for a superhydrophobic wing with a mass of 26 g the latter reached 42 g. The sample of the airfoil wing we prepared has a low adhesion, which helps in easy ice removal.

  15. 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.

  16. 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

  17. Size-dependent response of foraminiferal calcification to seawater carbonate chemistry

    NASA Astrophysics Data System (ADS)

    Henehan, Michael J.; Evans, David; Shankle, Madison; Burke, Janet E.; Foster, Gavin L.; Anagnostou, Eleni; Chalk, Thomas B.; Stewart, Joseph A.; Alt, Claudia H. S.; Durrant, Joseph; Hull, Pincelli M.

    2017-07-01

    The response of the marine carbon cycle to changes in atmospheric CO2 concentrations will be determined, in part, by the relative response of calcifying and non-calcifying organisms to global change. Planktonic foraminifera are responsible for a quarter or more of global carbonate production, therefore understanding the sensitivity of calcification in these organisms to environmental change is critical. Despite this, there remains little consensus as to whether, or to what extent, chemical and physical factors affect foraminiferal calcification. To address this, we directly test the effect of multiple controls on calcification in culture experiments and core-top measurements of Globigerinoides ruber. We find that two factors, body size and the carbonate system, strongly influence calcification intensity in life, but that exposure to corrosive bottom waters can overprint this signal post mortem. Using a simple model for the addition of calcite through ontogeny, we show that variable body size between and within datasets could complicate studies that examine environmental controls on foraminiferal shell weight. In addition, we suggest that size could ultimately play a role in determining whether calcification will increase or decrease with acidification. Our models highlight that knowledge of the specific morphological and physiological mechanisms driving ontogenetic change in calcification in different species will be critical in predicting the response of foraminiferal calcification to future change in atmospheric pCO2.

  18. 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.

  19. Senile Cardiac Calcification Syndrome: A Rare Case of Extensive Calcification of Left Ventricular Papillary Muscle

    PubMed Central

    Kim, Eun Jin; Song, Bong Gun; Sohn, Hyung Rae; Hong, Su-Min; Park, Dong Won; Heo, Seung Hye; Kim, Kye Yeon; Cho, Wook-Hyun; Choi, Suk-Koo

    2011-01-01

    Extensive papillary muscle calcification is uncommon and only scarce literature about causes and the clinical significance is available, whereas small calcific deposits are common findings in elderly people and are located most commonly at the apex. Papillary muscle calcification has been associated with coronary artery disease, dilated cardiomyopathy, mitral valve disease, hypercalcemia, and increased calcium phosphate product in end stage renal disease. We reported a rare case of extensive calcification of anterolateral papillary muscle diagnosed by echocardiography and multidetector computed tomography.

  20. Metal Ion-Loaded Nanofibre Matrices for Calcification Inhibition in Polyurethane Implants

    PubMed Central

    Singh, Charanpreet; Wang, Xungai

    2017-01-01

    Pathologic calcification leads to structural deterioration of implant materials via stiffening, stress cracking, and other structural disintegration mechanisms, and the effect can be critical for implants intended for long-term or permanent implantation. This study demonstrates the potential of using specific metal ions (MI)s for inhibiting pathological calcification in polyurethane (PU) implants. The hypothesis of using MIs as anti-calcification agents was based on the natural calcium-antagonist role of Mg2+ ions in human body, and the anti-calcification effect of Fe3+ ions in bio-prosthetic heart valves has previously been confirmed. In vitro calcification results indicated that a protective covering mesh of MI-doped PU can prevent calcification by preventing hydroxyapatite crystal growth. However, microstructure and mechanical characterisation revealed oxidative degradation effects from Fe3+ ions on the mechanical properties of the PU matrix. Therefore, from both a mechanical and anti-calcification effects point of view, Mg2+ ions are more promising candidates than Fe3+ ions. The in vitro MI release experiments demonstrated that PU microphase separation and the structural design of PU-MI matrices were important determinants of release kinetics. Increased phase separation in doped PU assisted in consistent long-term release of dissolved MIs from both hard and soft segments of the PU. The use of a composite-sandwich mesh design prevented an initial burst release which improved the late (>20 days) release rate of MIs from the matrix. PMID:28644382

  1. 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.

  2. [Positioning of bisphosphonates for vascular calcification].

    PubMed

    Okada, Yosuke; Mori, Hiroko; Tanaka, Yoshiya; Hashimoto, Osamu

    2010-11-01

    High-frequency severe atherosclerosis/calcinosis is observed in aging, diabetes mellitus and chronic dialysis, which leads to cardiovascular events. Recent progress in basic research has revealed certain similarities between processes of bone calcification and calcifications of vascular tissues which contribute to several cardiovascular diseases. These findings extend the link between bone remodeling and vascular calcification, opening perspectives toward novel therapeutic strategies, however, current evidence is not conclusive and further research is necessary to confirm these actions in the clinical setting.

  3. Calcification of thoracic aorta - solar eclipse sign.

    PubMed

    Dhoble, Abhijeet; Puttarajappa, Chethan

    2008-08-29

    Calcification of thoracic aorta is very common in old people, especially ones with hypertension. This can sometime be visible on plain chest radiograph. We present a case of a male patient who had extensive deposition of calcium in the thoracic aorta. The relationship between aortic calcification and coronary atherosclerosis remains contentious. Computed tomography of the thorax can display this calcification which appears like 'solar eclipse'.

  4. 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

  5. How divergence mechanisms influence disassortative mixing property in biology

    NASA Astrophysics Data System (ADS)

    Xu, Chunsui; Liu, Zengrong; Wang, Ruiqi

    2010-02-01

    The duplication-divergence mechanism of network growth has been widely investigated, especially in gene and protein networks. Both the duplication and divergence have a key role in biological network evolution. However, the relative roles of these mechanisms in the influence of disassortative property in protein interaction networks remain to be clarified. It has been shown that duplication can indeed make protein networks evolve towards disassortative networks. To make the relationship between the disassortative property and the duplication-divergence mechanism more clear, we further discuss how the divergence mechanism influences the disassortative property. We tested four different divergence mechanisms, i.e., node deletion, edge deletion, edge addition, and edge rewiring to study their effects on disassortative property. Our study highlights the crucial roles of different divergence evolution mechanisms.

  6. New concept of vascular calcification and metabolism.

    PubMed

    Nakagami, Hironori; Osako, Mariana K; Morishita, Ryuichi

    2011-01-01

    Vascular calcification is recently considered as one of the major complications and an independent risk factor of cardiovascular diseases. Although vascular calcification was commonly regarded as a passive process of mineral adsorption or precipitation, it tends to be an active process associated with the expression of growth factors, matrix proteins, and other bone-related proteins. There are 2 main types of vascular calcification. Intimal calcification is found in atherosclerotic plaques and is associated with the vascular events such as myocardial infarction. Medial calcification is usually associated with age and chronic kidney disease patients, which leads to increased vascular stiffness and reduced vascular compliance. Interestingly, our vascular calcification model using ApoE deficient mice showed intima calcification at sites of atherosclerotic plaques under high fat diet with ovariectomy. Thus, lipid metabolism is one of the therapeutic targets to prevent intima calcification of aorta. Previously we reported that ezetimibe significantly prevented atherosclerosis through lipid-lowering effects in ApoE-deficient mice. Based on these findings, we speculate that ezetimibe might prevent aortic intima calcification, which may give us the benefits to decrease vascular events.

  7. The anti-calcification potential of a silsesquioxane nanocomposite polymer under in vitro conditions: potential material for synthetic leaflet heart valve.

    PubMed

    Ghanbari, Hossein; Kidane, Asmeret G; Burriesci, Gaetano; Ramesh, Bala; Darbyshire, Arnold; Seifalian, Alexander M

    2010-11-01

    Calcification currently represents a major cause of failure of biological tissue heart valves. It is a complex phenomenon influenced by a number of biochemical and mechanical factors. Recent advances in material science offer new polymers with improved properties, potentially suitable for synthetic leaflets heart valves manufacturing. In this study, the calcification-resistance efficacy and mechanical and surface properties of a new nanocomposite polymeric material (polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane; POSS-PCU) which has been developed by our group are assessed by means of in vitro testing. In particular, thin sheets of nanocomposite, glutaraldehyde-fixed bovine pericardium (BP) and polyurethane (PU) were exposed to a calcium solution into a specially designed in vitro accelerated physiological pulsatile pressure system for a period of 31days and a total of 4×10(7) cycles. The samples were investigated for signs of calcification after exposure to calcium solution by means of X-ray, microscopic and chemical inspections. Mechanical and surface properties were also studied using stress-strain behaviour and surface morphology and hydrophobicity. Comparison shows that, in the experimental conditions, the level of calcification for the nanocomposite is considerably lower than for the fixed BP (p=0.008) and PU samples (p=0.015). Also, mechanical properties were unchanged in POSS-PCU, while there was a significant deterioration in PU samples (p<0.05). Hydrophobicity was significantly reduced in both the POSS-PCU and PU samples (p<0.0001). However, the POSS-PCU nanocomposite remained more hydrophobic than the PU sample (p<0.0001). Less platelet adhered to the POSS-PCU compared to the PU (p<0.0001). These results indicate that the use of this nanocomposite in synthetic leaflets heart valves may lead to potential advantages in terms of long-term performances and durability. Copyright © 2010. Published by Elsevier Ltd.

  8. 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

  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. Influence of carbon nanomaterials on the properties of paint coatings

    NASA Astrophysics Data System (ADS)

    Zhdanok, S. A.; Krauklis, A. V.; Borisevich, K. O.; Prokopchuk, N. P.; Nikolaichik, A. V.; Stanovoi, P. G.

    2011-11-01

    The conditions for obtaining carbon nanomaterials with the use of a low-temperature plasma are described. The product obtained was analyzed using the electron microscopy and a laser diffraction particle-size analyzer. The influence of the carbon nanomaterials on the physicochemical properties of paint coatings, their adhesion, impact and bending strengths, hardness, and protection characteristics was investigated.

  11. Influence of nanoclay on properties of HDPE/wood composites

    Treesearch

    Yong Lei; Qinglin Wu; Craig M. Clemons; Fei Yao; Yanjun Xu

    2007-01-01

    Composites based on high density polyethylene (HDPE), pine flour, and organic clay were made by melt compounding and then injection molding. The influence of clay on crystallization behavior, mechanical properties, water absorption, and thermal stability of HDPE/pine composites was investigated. The HDPE/pine composites containing exfoliated clay were made by a two-...

  12. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Vascular calcification in klotho deficient environment].

    PubMed

    Hasegawa, Tomoka; Yamamoto, Tomomaya; Hongo, Hiromi; Tsuboi, Kanako; Amizuka, Norio

    2015-05-01

    Klotho deficient (kl/kl) mice exhibit Möncheberg's vascular calcification in the tunica media due to hyperphosphatemia and hypercalcemia by mediating the disrupted signaling of FGF23/klotho axis. Recent studies have hypothesized the mechanism of medial vascular calcification : Vascular smooth muscle cells acquired excessive intake of phosphate ions undergo a phenotypic differentiation into osteoblasts and induce biological calcification in the tunica media. It is useful to clarify the underlying cellular mechanism of vascular calcification for the development of the treatment and preventive medicine. This review will introduce the histological and ultrastructual findings on medial vascular calcification in kl/kl mice.

  13. Influence of optical material properties on the perception of liquids.

    PubMed

    van Assen, Jan Jaap R; Fleming, Roland W

    2016-12-01

    In everyday life we encounter a wide range of liquids (e.g., water, custard, toothpaste) with distinctive optical appearances and viscosities. Optical properties (e.g., color, translucency) are physically independent of viscosity, but, based on experience with real liquids, we may associate specific appearances (e.g., water, caramel) with certain viscosities. Conversely, the visual system may discount optical properties, enabling "viscosity constancy" based primarily on the liquid's shape and motion. We investigated whether optical characteristics affect the perception of viscosity and other properties of liquids. We simulated pouring liquids with viscosities ranging from water to molten glass and rendered them with nine different optical characteristics. In Experiment 1, observers (a) adjusted a match stimulus until it had the same perceived viscosity as a test stimulus with different optical properties, and (b) rated six physical properties of the test stimuli (runniness, shininess, sliminess, stickiness, warmth, wetness). We tested moving and static stimuli. In Experiment 2, observers had to associate names with every liquid in the stimulus set. We find that observers' viscosity matches correlated strongly with the true viscosities and that optical properties had almost no effect. However, some ratings of liquid properties did show substantial interactions between viscosity and optical properties. Observers associate liquid names primarily with optical cues, although some materials are associated with a specific viscosity or combination of viscosity and optics. These results suggest viscosity is inferred primarily from shape and motion cues but that optical characteristics influence recognition of specific liquids and inference of other physical properties.

  14. Isolated posterior cruciate ligament calcification

    PubMed Central

    Koukoulias, Nikolaos E; Papastergiou, Stergios G

    2011-01-01

    The authors present a case of calcified posterior cruciate ligament (PCL). A 61-year-old female presented in our department reporting 12 months history of knee pain that was getting worse during the night. The patient was under medication for epileptic seizure, osteoporosis and hyperthyroidism. X-rays demonstrated calcification of the PCL. CT and MRI excluded any other intra-articular and extra-articular pathology. Arthroscopic debridement of the calcium deposits was performed and the symptoms resolved immediately, while the postoperative x-rays were normal. Histological examination confirmed the calcium nature of the lesion. Two years postoperatively the patient remains asymptomatic. PMID:22669889

  15. Silicon: a possible factor in bone calcification.

    PubMed

    Carlisle, E M

    1970-01-16

    Silicon, a relatively unknown trace element in nutritional research, has been uniquely localized in active calcification sites in young bone. Silicon increases directly with calcium at relatively low calcium concentrations and falls below the detection limit at compositions approaching hydroxyapatite. It is suggested that silicon is associated with calcium in an early stage of calcification.

  16. Aortic Valve Calcification in Mild Primary Hyperparathyroidism

    PubMed Central

    Iwata, Shinichi; Walker, Marcella Donovan; Di Tullio, Marco R.; Hyodo, Eiichi; Jin, Zhezhen; Liu, Rui; Sacco, Ralph L.; Homma, Shunichi

    2012-01-01

    Context: It is unclear whether cardiovascular disease is present in primary hyperparathyroidism (PHPT). Objective: Aortic valve structure and function were compared in PHPT patients and population-based controls. Design: This is a case-control study. Setting: The study was conducted in a university hospital metabolic bone disease unit. Participants: We studied 51 patients with PHPT and 49 controls. Outcome Measures: We measured the aortic valve calcification area and the transaortic pressure gradient. Results: Aortic valve calcification area was significantly higher in PHPT (0.24 ± 0.02 vs. 0.17 ± 0.02 cm2, p<0.01), although there was no difference in the peak transaortic pressure gradient, a functional measure of valvular calcification (5.6 ± 0.3 vs. 6.0 ± 0.3 mm Hg, P = 0.39). Aortic valve calcification area was positively associated with PTH (r = 0.34; P < 0.05) but not with serum calcium, phosphorus, or 25-hydroxyvitamin D levels or with calcium-phosphate product. Serum PTH level remained an independent predictor of aortic valve calcification area after adjustment for age, sex, body mass index, smoking status, history of hypercholesterolemia and hypertension, and estimated glomerular filtration rate. Conclusions: Mild PHPT is associated with subclinical aortic valve calcification. PTH, but not serum calcium concentration, predicted aortic valve calcification. PTH was a more important predictor of aortic valve calcification than well-accepted cardiovascular risk factors. PMID:22031523

  17. Vascular calcification: pathobiological mechanisms and clinical implications.

    PubMed

    Johnson, Rebecca C; Leopold, Jane A; Loscalzo, Joseph

    2006-11-10

    Once thought to result from passive precipitation of calcium and phosphate, it now appears that vascular calcification is a consequence of tightly regulated processes that culminate in organized extracellular matrix deposition by osteoblast-like cells. These cells may be derived from stem cells (circulating or within the vessel wall) or differentiation of existing cells, such as smooth muscle cells (SMCs) or pericytes. Several factors induce this transition, including bone morphogenetic proteins, oxidant stress, high phosphate levels, parathyroid hormone fragments, and vitamin D. Once the osteogenic phenotype is induced, cells gain a distinctive molecular fingerprint, marked by the transcription factor core binding factor alpha1. Alternatively, loss of inhibitors of mineralization, such as matrix gamma-carboxyglutamic acid Gla protein, fetuin, and osteopontin, also contribute to vascular calcification. The normal balance between promotion and inhibition of calcification becomes dysregulated in chronic kidney disease, diabetes mellitus, atherosclerosis, and as a consequence of aging. Once the physiological determinants of calcification are perturbed, calcification may occur at several sites in the cardiovascular system, including the intima and media of vessels and cardiac valves. Here, calcification may occur through overlapping yet distinct molecular mechanisms, each with different clinical ramifications. A variety of imaging techniques are available to visualize vascular calcification, including fluoroscopy, echocardiography, intravascular ultrasound, and electron beam computed tomography. These imaging modalities vary in sensitivity and specificity, as well as clinical application. Through greater understanding of both the mechanism and clinical consequences of vascular calcification, future therapeutic strategies may be more effectively designed and applied.

  18. Influence of Rubber Size on Properties of Crumb Rubber Mortars

    PubMed Central

    Yu, Yong; Zhu, Han

    2016-01-01

    Studies on the properties and applications of rubber cement-based materials are well documented. The sizes of rubbers used in these materials varied. However, information about the effects of rubber size on the properties of rubber cement-based materials, especially pore structure, mechanical strengths, and drying shrinkage properties, remains limited. Three groups of rubber with major particle sizes of 2–4 mm, 1–3 mm, and 0–2 mm were selected in this study. This paper presents experimental studies on the effects of rubber size on the consistency, fresh density, pore structure, mechanical properties, and drying shrinkage properties of crumb rubber mortars (CRMs). Results demonstrated that the consistency and fresh density of CRMs decreased with the rubber size. As to the pore structure, the total pore volume increased with the decrease of the rubber size. By contrast, the influence of the rubber size on the mesopore (<50 nm) volume is not as significant as that of the rubber content. The mechanical properties of CRMs decreased with the rubber size. Low rubber stiffness and large pore volumes, especially those of small sized rubbers, contribute to the reduction of CRMs strength. The drying shrinkage of CRM increases as the rubber size decreases. The influences of rubber size on capillary tension are not significant. Thus, the shrinkage increases with the decrease of rubber size mainly because of its function in the deformation modulus reduction of CRMs. PMID:28773649

  19. Influence of Rubber Size on Properties of Crumb Rubber Mortars.

    PubMed

    Yu, Yong; Zhu, Han

    2016-06-29

    Studies on the properties and applications of rubber cement-based materials are well documented. The sizes of rubbers used in these materials varied. However, information about the effects of rubber size on the properties of rubber cement-based materials, especially pore structure, mechanical strengths, and drying shrinkage properties, remains limited. Three groups of rubber with major particle sizes of 2-4 mm, 1-3 mm, and 0-2 mm were selected in this study. This paper presents experimental studies on the effects of rubber size on the consistency, fresh density, pore structure, mechanical properties, and drying shrinkage properties of crumb rubber mortars (CRMs). Results demonstrated that the consistency and fresh density of CRMs decreased with the rubber size. As to the pore structure, the total pore volume increased with the decrease of the rubber size. By contrast, the influence of the rubber size on the mesopore (<50 nm) volume is not as significant as that of the rubber content. The mechanical properties of CRMs decreased with the rubber size. Low rubber stiffness and large pore volumes, especially those of small sized rubbers, contribute to the reduction of CRMs strength. The drying shrinkage of CRM increases as the rubber size decreases. The influences of rubber size on capillary tension are not significant. Thus, the shrinkage increases with the decrease of rubber size mainly because of its function in the deformation modulus reduction of CRMs.

  20. 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

  1. 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.

  2. 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.

  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. 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.

  5. Influence of succinylation on physicochemical property of yak casein micelles.

    PubMed

    Yang, Min; Yang, Jitao; Zhang, Yuan; Zhang, Weibing

    2016-01-01

    Succinylation is a chemical-modification method that affects the physicochemical characteristics and functional properties of proteins. This study assessed the influence of succinylation on the physicochemical properties of yak casein micelles. The results revealed that surface hydrophobicity indices decreased with succinylation. Additionally, denaturation temperature and denaturation enthalpy decreased with increasing succinylation level, except at 82%. The buffering properties of yak casein micelles were affected by succinylation. It was found that chemical modification contributed to a slight shift of the buffering peak towards a lower pH value and a markedly increase of the maximum buffering values of yak casein micelles at pH 4.5-6.0 and pH < 3. Succinylation increased yak casein micellar hydration and whiteness values. The findings obtained from this study will provide the basic information on the physicochemical properties of native and succinylated yak casein micelles.

  6. 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

  7. Calcification of the ligamentum arteriosum in adults: CT features

    SciTech Connect

    Wimpfheimer, O.; Haramati, L.B.; Haramati, N.

    1996-01-01

    The present study describes the frequency and pattern of ligamentum arteriosum calcification seen on chest CT in adults. We retrospectively reviewed 402 sequential unenhanced chest CT studies for ligamentum arteriosum calcification, atherosclerotic cardiac or aortic calcification, and granulomatous calcification. The pattern of calcification was characterized as curvilinear, punctate, or clumped. Mean patient age was 60 ({+-}18, range 18-97) years with 214 women (53%) and 188 men (47%). Of these patients 194 (48%) had calcification in the ligamentum arteriosum including 26 (6%) with calcification in the ligamentum arteriosum alone, 108 (27%) with atherosclerotic calcification, 11 (3%) with granulomatous calcification, and 49 (12%) with both. A total of 100 patients (25%) had no calcifications. In the study population 169 patients (42%) had atherosclerotic calcification, 32 (8%) had granulomatous calcification, and 75 (19%) had both. The patterns of calcification for the 26 patients with calcification of the ligamentum arteriosum alone were curvilinear (7 patients, 27%), punctate (17 patients, 65%), and clumped (2 patients, 8%). The pattern of ligamentum arteriosum calcification for the 108 patients with only atherosclerotic and ligamentum arteriosum calcification was curvilinear (28 patients, 26%), punctate (32 patients, 30%), and clumped (48 patients, 44%). The patients without any calcifications and the patients with ligamentum arteriosum calcification formed one group (based on their similarity in age, mean 47 years) with a prevalence of ligamentum arteriosum calcification of 21%. The patients with atherosclerotic and ligamentum arteriosum calcification formed a second group (mean age 71 years) with a prevalence of ligamentum arteriosum calcification of 65%. On unenhanced chest CT calcification of the ligamentum arteriosum is a common finding in adults and increases in prevalence with increasing age and atherosclerosis. 6 refs., 4 figs., 1 tab.

  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. 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. Influence of trace elements on dental enamel properties: A review.

    PubMed

    Qamar, Zeeshan; Haji Abdul Rahim, Zubaidah Binti; Chew, Hooi Pin; Fatima, Tayyaba

    2017-01-01

    Dental enamel, an avascular, irreparable, outermost and protective layer of the human clinical crown has a potential to withstand the physico-chemical effects and forces. These properties are being regulated by a unique association among elements occurring in the crystallites setup of human dental enamel. Calcium and phosphate are the major components (hydroxyapatite) in addition to some trace elements which have a profound effect on enamel. The current review was planned to determine the aptitude of various trace elements to substitute and their influence on human dental enamel in terms of physical and chemical properties.

  11. On the influence of surfactant over friction properties of steel

    NASA Astrophysics Data System (ADS)

    Upadhyay, R. K.; Kumaraswamidhas, L. A.

    2014-07-01

    Surfactant wetting properties are important for any tribological system. In order to explore these properties the influence of four surfactant i.e. sodium hexametaphosphate (SHMP); zinc dithiodiphosphate (ZDDP); sodium dodecyl sulphate (SDS); and cetrimonium bromide (C-TAB); on the friction behaviour of physical vapour deposition (PVD) coated surfaces were studied using pin on disk tribometer. Anionic, cationic and non-ionic surfactants are dispersed in oil/water medium. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and X-ray diffraction (XRD) analysis was performed to obtain the surface morphology, chemical composition and structure of the material.

  12. Calcification

    MedlinePlus

    ... joints, and soft tissue tumors. In: Kumar V, Abbas AK, Aster JC, eds. Robbins and Cotran Pathologic ... PA: Elsevier Saunders; 2015:chap 26. Kumar V, Abbas AK, Aster JC. Cellular responses to stress and ...

  13. 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.

  14. Pathology of Human Coronary and Carotid Artery Atherosclerosis and Vascular Calcification in Diabetes Mellitus.

    PubMed

    Yahagi, Kazuyuki; Kolodgie, Frank D; Lutter, Christoph; Mori, Hiroyoshi; Romero, Maria E; Finn, Aloke V; Virmani, Renu

    2017-02-01

    The continuing increase in the prevalence of diabetes mellitus in the general population is predicted to result in a higher incidence of cardiovascular disease. Although the mechanisms of diabetes mellitus-associated progression of atherosclerosis are not fully understood, at clinical and pathological levels, there is an appreciation of increased disease burden and higher levels of arterial calcification in these subjects. Plaques within the coronary arteries of patients with diabetes mellitus generally exhibit larger necrotic cores and significantly greater inflammation consisting mainly of macrophages and T lymphocytes relative to patients without diabetes mellitus. Moreover, there is a higher incidence of healed plaque ruptures and positive remodeling in hearts from subjects with type 1 diabetes mellitus and type 2 diabetes mellitus, suggesting a more active atherogenic process. Lesion calcification in the coronary, carotid, and other arterial beds is also more extensive. Although the role of coronary artery calcification in identifying cardiovascular disease and predicting its outcome is undeniable, our understanding of how key hormonal and physiological alterations associated with diabetes mellitus such as insulin resistance and hyperglycemia influence the process of vascular calcification continues to grow. Important drivers of atherosclerotic calcification in diabetes mellitus include oxidative stress, endothelial dysfunction, alterations in mineral metabolism, increased inflammatory cytokine production, and release of osteoprogenitor cells from the marrow into the circulation. Our review will focus on the pathophysiology of type 1 diabetes mellitus- and type 2 diabetes mellitus-associated vascular disease with particular focus on coronary and carotid atherosclerotic calcification.

  15. Synergic Impact of Vascular Calcification and Low Autonomic Tone in Mortality of Hemodialysis Patients.

    PubMed

    Ng, Hwee-Yeong; Hsueh, Shu-Kai; Lee, Yueh-Ting; Chiou, Terry Ting-Yu; Huang, Pei-Chen; Lee, Chien-Te

    2017-06-22

    Both cardiovascular calcification and autonomic dysfunction are frequently encountered in hemodialysis patients. We aimed to investigate the relationship between cardiovascular calcification and heart rate variability (HRV) and their influence on long-term outcome. Seventy-eight hemodialysis patients underwent echocardiogram and radiography of the pelvis and hands to identify valvular and vascular calcification. HRV was evaluated using a commercial machine. Based on the average, the patients were divided into higher and lower subgroups of high frequency (HF) and low frequency (LF) respectively. Patients with higher LF were younger and were found to have a lower proportion of diabetes. Their hemoglobin, albumin, and bone morphogenic protein (BMP)-7 levels were significantly higher and both high-sensitive C-reactive protein (hs-CRP) and osteoprotegerin levels were lower (all p < 0.05). In patients of the higher HF group, the proportion of diabetes was lower but they were found to have higher levels of BMP-7 and lower levels of hs-CRP, interleukin-6 (all p < 0.05). Significantly higher LF and HF were noted in patients without vascular calcification, but only hand artery (HA) calcification was negatively correlated with both LF and HF in multivariate analysis. Low LF and high hs-CRP were the independent predictors of mortality. Coexistence of low LF band and HA calcification was associated with the worse outcome. Abnormal autonomic nervous function was closely related to inflammation and mortality in hemodialysis patients. Calcification of HA was associated with autonomic dysfunction and patients with lower autonomic tone and HA calcification had the highest mortality rate in this population. © 2017 S. Karger AG, Basel.

  16. Plasmin Prevents Dystrophic Calcification After Muscle Injury.

    PubMed

    Mignemi, Nicholas A; Yuasa, Masato; Baker, Courtney E; Moore, Stephanie N; Ihejirika, Rivka C; Oelsner, William K; Wallace, Christopher S; Yoshii, Toshitaka; Okawa, Atsushi; Revenko, Alexey S; MacLeod, A Robert; Bhattacharjee, Gourab; Barnett, Joey V; Schwartz, Herbert S; Degen, Jay L; Flick, Matthew J; Cates, Justin M; Schoenecker, Jonathan G

    2017-02-01

    Extensive or persistent calcium phosphate deposition within soft tissues after severe traumatic injury or major orthopedic surgery can result in pain and loss of joint function. The pathophysiology of soft tissue calcification, including dystrophic calcification and heterotopic ossification (HO), is poorly understood; consequently, current treatments are suboptimal. Here, we show that plasmin protease activity prevents dystrophic calcification within injured skeletal muscle independent of its canonical fibrinolytic function. After muscle injury, dystrophic calcifications either can be resorbed during the process of tissue healing, persist, or become organized into mature bone (HO). Without sufficient plasmin activity, dystrophic calcifications persist after muscle injury and are sufficient to induce HO. Downregulating the primary inhibitor of plasmin (α2-antiplasmin) or treating with pyrophosphate analogues prevents dystrophic calcification and subsequent HO in vivo. Because plasmin also supports bone homeostasis and fracture repair, increasing plasmin activity represents the first pharmacologic strategy to prevent soft tissue calcification without adversely affecting systemic bone physiology or concurrent muscle and bone regeneration. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

  17. Corneal calcification after amniotic membrane transplantation

    PubMed Central

    Anderson, S B; de Souza, R Ferreira; Hofmann-Rummelt, C; Seitz, B

    2003-01-01

    Background/aims: Amniotic membrane transplantation (AMT) has become well established as a treatment for chronic epithelial defects, conjunctival reconstruction, and partial limbal cell deficiency. The aim of this study was to describe cases of corneal calcification following AMT and to search for risk factors that might predispose to this unusual finding. Methods: Details of 117 AMTs on 93 corneas of 91 patients with a follow up period of at least 1 month performed since 1999 were collected prospectively. In those with calcification clinical photographs were studied and the medical records retrospectively examined. Results: 15 calcifications in 117 AMTs (12.8%) were identified, occurring 3–17 (median 6.1) weeks after AMT, during a follow up period of 4–151 (median 25) weeks. Overall epithelial healing rate was 83%. Calcification covered a surface area between 0.7–40.5 mm2 maximum size with varied morphology. The primary diagnosis was diverse. Risk factors included the use of phosphate eye drops and pre-existing calcification in the operative or other eye. No patient with a “patch” AMT developed calcification. Conclusions: Corneal calcification occurs after some cases of AMT. A common risk factor was the postoperative use of phosphate containing eye drops. PMID:12714401

  18. Exploring relationships of calcification rate with respiration rate and predator cue presence in juvenile Crassostrea virginica

    NASA Astrophysics Data System (ADS)

    McCutcheon, M.; Hu, X.

    2016-02-01

    The eastern oyster (Crassostrea virginica) is a biologically and economically important calcifier that has been experiencing a global population decline due to multiple stressors. The process of biomineralization is essential in the growth and predator defense of oysters. Several studies investigating morphological and mechanical shell properties have noted a phenotypic plasticity in response to predator presence. We present the first study that attempts to detect an alteration in the calcification rate of juvenile C. virginica as well as measure respiration rates in the presence and absence of predator exudates. An alkalinity anomaly technique was used to quantify calcification and respiration rates of oysters exposed to blue crab or mud crab cues or a no cue control condition. No significant differences in calcification rate were detected between predator and control treatments. However, the linear relationship between calcification and respiration rates differed between treatments. This changing relationship is not fully understood and warrants further investigation. In addition, this study also revealed our experimental oysters maintained calcification rates comparable to literature values while respiration rates were an order of magnitude lower than previously reported levels. Future direction for this research involves inclusion of acidification treatments. Any environmental factors (including predator presence) that may on their own or in conjunction with estuarine acidification alter calcification (or respiration) rates will impact the local to regional carbon cycle as well as oyster fitness and consequent future population dynamics.

  19. 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

  20. Chondrocyte apoptosis is not essential for cartilage calcification: evidence from an in vitro avian model.

    PubMed

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

    2007-01-01

    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

  1. Application of shape analysis to mammographic calcifications

    SciTech Connect

    Shen, L.; Rangayyan, R.M. . Dept. of Electrical and Computer Engineering); Desautels, J.E.L. . Dept. of Radiology)

    1994-06-01

    The authors have developed a set of shape factors to measure the roughness of contours of calcifications in mammograms and for use in their classification as malignant or benign. The analysis of mammograms is performed in three stages. First, a region growing technique is used to obtain the contours of calcifications. Then, three measures of shape features, including compactness, moments, and Fourier descriptors are computed for each region. Finally, their applicability for classification is studied by using the three shape measures to form feature vectors. Classification of 143 calcifications from 18 biopsy-proven cases as benign or malignant using the three measures with the nearest-neighbor method was 100% accurate.

  2. Distribution of calcification within the pineal gland.

    PubMed

    Pilling, J R; Hawkins, T D

    1977-11-01

    The distribution of calcification in the normal pineal gland was investigated by a macroradiographic in vitro technique. The centre of calcification in 72 out of 73 glands studied was within 2 mm of the mid-line of the gland. In one gland it lay 2.6 mm from the mid-line. These findings explain the accepted normal limits for pineal calcification on the standard semi-axial projection of the skull of up to 2 mm to either side of the mid-line and the occasional measurement in excess of this in normal subjects.

  3. Diffuse soft tissue calcification in tumoral calcinosis

    SciTech Connect

    Feldman, E.S.; Schumacher, H.R.; Dalinka, M.K.

    1981-10-01

    Tumoral calcinosis is a rare disease characterized biochemically by hyperphosphatemia, normocalcemia, and reduced fractional excretion of phosphate. Radiographically, it has been defined by the presence of large, amorphous juxtaarticular calcific deposits. A 53-year-old woman with tumoral calcinosis was found to have unusual diffuse soft tissue calcification indistinguishable from that usually seen in collagen vascular disease and previously referred to as calcinosis universalis. It is suggested that tumoral calcinosis is a misnomer as the calcification seen in patients with this disease may be 'tumoral' or diffuse.

  4. Cardiovascular calcification: current controversies and novel concepts.

    PubMed

    Ruiz, Jessica L; Hutcheson, Joshua D; Aikawa, Elena

    2015-01-01

    Cardiovascular calcification is a commonly observed but incompletely understood mechanism of increased atherosclerotic plaque instability and accelerated aortic valve stenosis. Traditional histological staining and imaging techniques are nonspecific for the type of mineral present in calcified tissues, information that is critical for proper validation of in vitro and in vivo models. This review highlights current gaps in our understanding of the biophysical implications and the cellular mechanisms of valvular and vascular calcification and how they may differ between the two tissue types. We also address the hindrances of current cell culture systems, discussing novel platforms and important considerations for future studies of cardiovascular calcification. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. 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.

  6. Reduced calcification in modern Southern Ocean planktonic foraminifera

    NASA Astrophysics Data System (ADS)

    Moy, Andrew D.; Howard, William R.; Bray, Stephen G.; Trull, Thomas W.

    2009-04-01

    Anthropogenic carbon dioxide has been accumulating in the oceans, lowering both the concentration of carbonate ions and the pH (ref. 1), resulting in the acidification of sea water. Previous laboratory experiments have shown that decreased carbonate ion concentrations cause many marine calcareous organisms to show reduced calcification rates. If these results are widely applicable to ocean settings, ocean acidification could lead to ecosystem shifts. Planktonic foraminifera are single-celled calcite-secreting organisms that represent between 25 and 50% of the total open-ocean marine carbonate flux and influence the transport of organic carbon to the ocean interior. Here we compare the shell weights of the modern foraminifer Globigerina bulloides collected from sediment traps in the Southern Ocean with the weights of shells preserved in the underlying Holocene-aged sediments. We find that modern shell weights are 30-35% lower than those from the sediments, consistent with reduced calcification today induced by ocean acidification. We also find a link between higher atmospheric carbon dioxide and low shell weights in a 50,000-year-long record obtained from a Southern Ocean marine sediment core. It is unclear whether reduced calcification will affect the survival of this and other species, but a decline in the abundance of foraminifera caused by acidification could affect both marine ecosystems and the oceanic uptake of atmospheric carbon dioxide.

  7. Vascular calcification in chronic kidney disease: Pathogenesis and clinical implication

    PubMed Central

    Disthabanchong, Sinee

    2012-01-01

    Cardiovascular disease is the leading cause of death among patients with chronic kidney disease (CKD). Vascular calcification (VC) is one of the independent risk factors associated with cardiovascular disease and cardiovascular mortality in both the general population and CKD patients. Earlier evidence revealed substantially higher prevalence of VC in young adults on chronic hemodialysis compared to the general population in the same age range, indicating the influence of CKD-related risk factors on the development of VC. Pathogenesis of VC involves an active, highly organized cellular transformation of vascular smooth muscle cells to bone forming cells evidenced by the presence of bone matrix proteins in the calcified arterial wall. VC occurs in both the intima and the media of arterial wall with medial calcification being more prevalent in CKD. In addition to traditional cardiovascular risks, risk factors specific to CKD such as phosphate retention, excess of calcium, history of dialysis, active vitamin D therapy in high doses and deficiency of calcification inhibitors play important roles in promoting the development of VC. Non-contrast multi-slice computed tomography has often been used to detect coronary artery calcification. Simple plain radiographs of the lateral lumbar spine and pelvis can also detect VC in the abdominal aorta and femoral and iliac arteries. Currently, there is no specific therapy to reverse VC. Reduction of calcium load, lowering phosphate retention using non-calcium containing phosphate binders, and moderate doses of active vitamin D may attenuate progression. Parenteral sodium thiosulfate has also been shown to delay VC progression. PMID:24175241

  8. 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

  9. 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.

  10. Magnesium reduces calcification in bovine vascular smooth muscle cells in a dose-dependent manner

    PubMed Central

    Peter, Mirjam E.; Sevinc Ok, Ebru; Celenk, Fatma Gul; Yilmaz, Mumtaz; Steppan, Sonja; Asci, Gulay; Ok, Ercan; Passlick-Deetjen, Jutta

    2012-01-01

    Background. Vascular calcification (VC), mainly due to elevated phosphate levels, is one major problem in patients suffering from chronic kidney disease. In clinical studies, an inverse relationship between serum magnesium and VC has been reported. However, there is only few information about the influence of magnesium on calcification on a cellular level available. Therefore, we investigated the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in bovine vascular smooth muscle cells (BVSMCs). Methods. BVSMCs were incubated with calcification media for 14 days while simultaneously increasing the magnesium concentration. Calcium deposition, transdifferentiation of cells and apoptosis were measured applying quantification of calcium, von Kossa and Alizarin red staining, real-time reverse transcription–polymerase chain reaction and annexin V staining, respectively. Results. Calcium deposition in the cells dramatically increased with addition of BGP and could be mostly prevented by co-incubation with magnesium. Higher magnesium levels led to inhibition of BGP-induced alkaline phosphatase activity as well as to a decreased expression of genes associated with the process of transdifferentiation of BVSMCs into osteoblast-like cells. Furthermore, estimated calcium entry into the cells decreased with increasing magnesium concentrations in the media. In addition, higher magnesium concentrations prevented cell damage (apoptosis) induced by BGP as well as progression of already established calcification. Conclusions. Higher magnesium levels prevented BVSMC calcification, inhibited expression of osteogenic proteins, apoptosis and further progression of already established calcification. Thus, magnesium is influencing molecular processes associated with VC and may have the potential to play a role for VC also in clinical situations. PMID:21750166

  11. The Influence of Large-scale Environments on Galaxy Properties

    NASA Astrophysics Data System (ADS)

    Wei, Yu-qing; Wang, Lei; Dai, Cai-ping

    2017-07-01

    The star formation properties of galaxies and their dependence on environments play an important role for understanding the formation and evolution of galaxies. Using the galaxy sample of the Sloan Digital Sky Survey (SDSS), different research groups have studied the physical properties of galaxies and their large-scale environments. Here, using the filament catalog from Tempel et al. and the galaxy catalog of large-scale structure classification from Wang et al., and taking the influence of the galaxy morphology, high/low local density environment, and central (satellite) galaxy into consideration, we have found that the properties of galaxies are correlated with their residential large-scale environments: the SSFR (specific star formation rate) and SFR (star formation rate) strongly depend on the large-scale environment for spiral galaxies and satellite galaxies, but this dependence is very weak for elliptical galaxies and central galaxies, and the influence of large-scale environments on galaxies in low density region is more sensitive than that in high density region. The above conclusions remain valid even for the galaxies with the same mass. In addition, the SSFR distributions derived from the catalogs of Tempel et al. and Wang et al. are not entirely consistent.

  12. Influence of coal properties on NO{sub x} emissions

    SciTech Connect

    Conn, S.K.; Bond, R.A.; Thompson, A.W.; Allen, J.W.

    1995-12-31

    Fundamental coal characterization work has indicated the particular properties which influence the performance of coals in Low-NO{sub x} combustion systems. These properties influence NO{sub x} emissions as well as unburned carbon levels, slagging and fouling tendencies. The performance of a 265 MW boiler retrofitted with a flame attachment nozzle burner Low-NO{sub x} system is discussed in terms of these basic coal properties. Owensboro Municipal Utilities` Elmer Smith Station is comprised of one 151 MW{sub E} cyclone-fired and one 265 MW{sub E} tangentially-fired pulverized coal burning generating unit. It is located in Owensboro, Kentucky on the Ohio River, and provides electric power to the city of Owensboro as well as a neighboring utility. The station historically burn approximately 1.1 million tons of 6lb SO{sub 2}/mmBTU coal from the surrounding western Kentucky coal fields. A typical proximate analysis for this fuel is shown.

  13. The influence of biomechanical properties and cannabinoids on tumor invasion.

    PubMed

    Hohmann, Tim; Grabiec, Urszula; Ghadban, Chalid; Feese, Kerstin; Dehghani, Faramarz

    2017-01-02

    Cannabinoids are known to have an anti-tumorous effect, but the underlying mechanisms are only sparsely understood. Mechanical characteristics of tumor cells represent a promising marker to distinguish between tumor cells and the healthy tissue. We tested the hypothesis whether cannabinoids influence the tumor cell specific mechanical and migratory properties and if these factors are a prognostic marker for the invasiveness of tumor cells. 3 different glioblastoma cell lines were treated with cannabinoids and changes of mechanical and migratory properties of single cells were measured using atomic force microscopy and time lapse imaging. The invasiveness of cell lines was determined using a co-culture model with organotypic hippocampal slice cultures. We found that cannabinoids are capable of influencing migratory and mechanical properties in a cell line specific manner. A network analysis revealed a correlation between a "generalized stiffness" and the invasiveness for all tumor cell lines after 3 and 4 d of invasion time: r3d = -0.88 [-0.52;-0.97]; r4d = -0.90 [-0.59;-0.98]. Here we could show that a "generalized stiffness" is a profound marker for the invasiveness of a tumor cell population in our model and thus might be of high clinical relevance for drug testing. Additionally cannabinoids were shown to be of potential use for therapeutic approaches of glioblastoma.

  14. 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.

  15. Treating calcific aortic stenosis: an evolving science.

    PubMed

    Hull, Christine L

    2012-01-01

    Calcific aortic stenosis is a common valvular disease, but its pathophysiology remains undetermined and important considerations exist for treatment. Pathophysiology, treatment by the advanced practice nurse, and literature review are discussed in the context of a case study.

  16. Alendronate conjugated nanoparticles for calcification targeting.

    PubMed

    Li, Nanying; Song, Juqing; Zhu, Guanglin; Shi, Xuetao; Wang, Yingjun

    2016-06-01

    In this article, the synthesis of a novel calcification-targeting nanoparticle (NP) is reported, which is realized through dopamine self-polymerization on the poly(lactic-co-glycolic acid) (PLGA) particle surface and subsequent alendronate conjugation. Cell viability and proliferation tests confirmed that such particle has low cytotoxicity and good biocompatibility. Experiments were designed to observe whether the synthesized NPs can pass through an obstructive hydrogel and directly bind themselves to hydroxyapatite (HA) NPs (mimicking calcified spots) and HA porous scaffolds (mimicking calcified tissues); and the result was positive, indicating ingenious targeting of NPs on calcifications. The calcification-targeting NPs are expected to be with promising applications on calcification-related disease diagnoses and therapies. Copyright © 2016. Published by Elsevier B.V.

  17. The Role of Epigenetics in Arterial Calcification

    PubMed Central

    Wu, Shan-Shan; Lin, Xiao; Yuan, Ling-Qing; Liao, Er-Yuan

    2015-01-01

    Arterial calcification is highly prevalent and correlated with cardiovascular mortality, especially in patients with ESRD or diabetes. The pathogenesis of arterial calcification is multifactorial, with both genetic and environmental factors being implicated. In recent years, several mechanisms contributing to arterial calcification have been proposed. However, these can only explain a small proportion of the variability in arterial calcification, which is a major obstacle for its prevention and management. Epigenetics has emerged as one of the most promising areas that may fill in some of the gaps in our current knowledge of the interaction between the environmental insults with gene regulation in the development of diseases. Epigenetics refers to heritable and acquired changes in gene transcription that occur independently of the DNA sequence. Well-known components of epigenetic regulation include DNA methylation, histone modifications, and microRNAs. Epigenetics research in the regulation of arterial calcification has only recently been elucidated. In this review, we will summarise recent progress in epigenetic pathways involved in arterial calcification and discuss potential therapeutic interventions based on epigenetic mechanisms. PMID:26221588

  18. A comparative study of physiologic intracranial calcifications.

    PubMed

    Abbassioun, K; Aarabi, B; Zarabi, M

    1978-04-01

    It has been the impression of clinicians that pineal calcification is infrequent in Shiraz, Iran. In order to evaluate this clinical impression 2000 consecutive skul X-rays taken at Saadi Hospital, Shiraz, Iran, were reviewed for the presence of physiologic intracranial calcifications. The incidence of these clasifications in male and female in consecutive age groups of 10 years from 0 to over 70 years of age were assessed and compared with previous reports from other countries. The average incidence of pineal calcification for those over 20 years of age was 18.29% in this study compared with 55% in the U.S.A. The incidence of calcification in the choroid plexus and the falx cerebri was also considerably less than previously reported. The literature is reviewed and the possible causes for the geographical differences in the reported frequency of physiologic intracranial calcifications is discussed. It is possible that racial and dietary factors may be significant in the variation in the incidence of pineal and other cranial calcifications noted in different countries. Within a population group, age and sex are additional factors.

  19. Treatment with pyrophosphate inhibits uremic vascular calcification.

    PubMed

    O'Neill, W Charles; Lomashvili, Koba A; Malluche, Hartmut H; Faugere, Marie-Claude; Riser, Bruce L

    2011-03-01

    Pyrophosphate, which may be deficient in advanced renal failure, is a potent inhibitor of vascular calcification. To explore its use as a potential therapeutic, we injected exogenous pyrophosphate subcutaneously or intraperitoneally in normal rats and found that their plasma pyrophosphate concentrations peaked within 15 min. There was a single exponential decay with a half-life of 33 min. The kinetics were indistinguishable between the two routes of administration or in anephric rats. The effect of daily intraperitoneal pyrophosphate injections on uremic vascular calcification was then tested in rats fed a high-phosphate diet containing adenine for 28 days to induce uremia. Although the incidence of aortic calcification varied and was not altered by pyrophosphate, the calcium content of calcified aortas was significantly reduced by 70%. Studies were repeated in uremic rats given calcitriol to produce more consistent aortic calcification and treated with sodium pyrophosphate delivered intraperitoneally in a larger volume of glucose-containing solution to prolong plasma pyrophosphate levels. This maneuver significantly reduced both the incidence and amount of calcification. Quantitative histomorphometry of bone samples after double-labeling with calcein indicated that there was no effect of pyrophosphate on the rates of bone formation or mineralization. Thus, exogenous pyrophosphate can inhibit uremic vascular calcification without producing adverse effects on bone.

  20. Cellular Mechanisms of Aortic Valve Calcification

    PubMed Central

    Leopold, Jane A.

    2012-01-01

    Acquired aortic valve disease and valvular calcification is highly prevalent in adult populations worldwide and is associated with significant cardiovascular morbidity and mortality. At present, there are no medical therapies that will prevent or regress aortic valve calcification or stenosis and surgical or transcatheter aortic valve replacement remain the only effective therapies for treating this disease. In the setting of valve injury as a result of exposure to biochemical mediators or hemodynamic forces, normal homeostatic processes are disrupted resulting in extracellular matrix degradation, aberrant matrix deposition and fibrosis, inflammatory cell infiltration, lipid accumulation, and neoangiogenesis of the valve tissue and, ultimately, calcification of the valve. Calcification of the aortic valve is now understood to be an active process that involves the coordinated actions of resident valve endothelial and interstitial cells, circulating inflammatory and immune cells, and bone marrow-derived cells. These cells may undergo a phenotype transition to become osteoblast-like cells and elaborate bone matrix, endothelial-to-mesenchymal transition, and form matrix vesicles that serve as a nidus for microcalcifications. Each of these mechanisms has been shown to contribute to aortic valve calcification suggesting that strategies that target these cellular events may lead to novel therapeutic interventions to halt the progression or reverse aortic valve calcification. PMID:22896576

  1. Three-dimensional imaging of breast calcifications

    NASA Astrophysics Data System (ADS)

    Maidment, Andrew D. A.; Albert, Michael; Conant, Emily F.

    1998-03-01

    Approximately 50 percent of breast cancers are detected on the basis of calcifications alone. Regrettably, the presence of such calcifications is non-specific; only 30 percent of biopsies based on suspicious calcifications are malignant. We have investigated three methods (LVR) for 3D imaging and analysis of microcalcifications. Our aim is to increase specificity by more accurately distinguishing between calcifications indicative of benign and malignant breast lesions. We have demonstrated that 3D imaging of calcifications is possible using an LVR technique that includes semi-automated segmentation, correlation, and reconstruction of the calcifications. A clinical study of he LVR method is ongoing in which 2D film and digital images are compared to 3D images. The images are evaluated using a rating of 1 to 5, where 1 equals definitely benign, 5 equals definitely malignant, and a score of 3 or higher requires biopsy. To date, 3 radiologists have evaluated the images of 44 patients for which biopsy results were available. The use of 2D and 3D digital images resulted in doubling the diagnostic accuracy from 36 percent to 77 percent. Comparison to other techniques is ongoing. Additionally, a high resolution CT scanner for breast tissue specimens is under construction for comparison of the reconstructed images to a 'gold standard'.

  2. Treatment with pyrophosphate inhibits uremic vascular calcification

    PubMed Central

    O’Neill, W. Charles; Lomashvili, Koba A.; Malluche, Hartmut H.; Faugere, Marie-Claude; Riser, Bruce L.

    2011-01-01

    Pyrophosphate, which may be deficient in advanced renal failure, is a potent inhibitor of vascular calcification. To explore its use as a potential therapeutic, we injected exogenous pyrophosphate subcutaneously or intraperitoneally in normal rats and found that their plasma pyrophosphate concentrations peaked within 15 min. There was a single exponential decay with a half-life of 33 min. The kinetics were indistinguishable between the two routes of administration or in anephric rats. The effect of daily intraperitoneal pyrophosphate injections on uremic vascular calcification was then tested in rats fed a high-phosphate diet containing adenine for 28 days to induce uremia. Although the incidence of aortic calcification varied and was not altered by pyrophosphate, the calcium content of calcified aortas was significantly reduced by 70%. Studies were repeated in uremic rats given calcitriol to produce more consistent aortic calcification and treated with sodium pyrophosphate delivered intraperitoneally in a larger volume of glucose-containing solution to prolong plasma pyrophosphate levels. This maneuver significantly reduced both the incidence and amount of calcification. Quantitative histomorphometry of bone samples after double-labeling with calcein indicated that there was no effect of pyrophosphate on the rates of bone formation or mineralization. Thus, exogenous pyrophosphate can inhibit uremic vascular calcification without producing adverse effects on bone. PMID:21124302

  3. Influence of Moisture on Mechanical Properties of Cellulose Insulation Paper

    NASA Astrophysics Data System (ADS)

    Wang, Y. Y.; Tian, M.; Xu, H. X.; Fan, P.

    2014-01-01

    This paper aims to investigate the impact of moisture on mechanical properties of insulation paper. According to the molecular modeling approach proposed by Theodorou, the amorphous cellulose models of insulation paper with different moisture contents were built up to calculate mechanical parameters and hydrogen bond networks. And relevant conclusions could be drawn through further analysis on these calculation results: water molecules can destroy hydrogen bond network between the neighboring cellulose molecules, which might be responsible for the significant decrease of Young's modulus and other mechanical parameters, while no appreciable effect of intramolecular hydrogen bonds on mechanical properties was detected. Thus tensile tests were also carried out to study the moisture influence on the Young's modulus, by which the result of the simulation was approved.

  4. Influence of surfactants on diesel water shedding properties

    SciTech Connect

    McCarthy, K.J.; O`Brien, T.J.; Weers, J.J.

    1994-10-01

    The properties of emulsions formed when water contacts low sulfur diesel fuel supplemented with indigenous surfactants or chemical additives were studied. Small amounts of the additives were found to have dramatic effects on the stabilization or breaking of the emulsions formed during ASTM D-1094 testing. Dynamic interfacial tension measurements were also recorded to determine the influence of the surfactants on the interfacial film surrounding the water droplets in the emulsions. The results of both the ASTM test and the interfacial tension measurements were compared. 18 refs., 19 figs.

  5. Change of solar cell element properties influenced by adsorbed atoms

    NASA Astrophysics Data System (ADS)

    Livshits, A. I.; Romanovskij, Y. A.; Zavilopulo, A. N.; Zhukov, A. I.; Snegurskij, A. V.

    A series of experimental studies on the influence of alkali and alkaline-earth metal films on electro-physical properties of solar elements used for spacecraft energy supply was carried out. Metal films of different thicknesses were deposited using an effusion source, the mass of the film was calculated using measured atomic beam density. The Mg film thickness was determined by means of microscopic technique. The dynamics of current-to-voltage characteristic variation was studied for different film thickness and chemical composition in vacuum and in oxygen atmosphere.

  6. 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

  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. The impact of osteophytic and vascular calcifications on vertebral mineral density measurements in men.

    PubMed

    Orwoll, E S; Oviatt, S K; Mann, T

    1990-04-01

    To evaluate the influence of extravertebral calcification on spinal bone density determinations, we measured lumbar vertebral density in 71 hospitalized and 58 normal men using dual photon absorptiometry. The extent of vascular and osteophytic calcification was graded from lateral lumbar radiographs. Fifty-five (43%) of the subjects had identifiable osteophytes, and 86 (67%) had vascular calcifications. Despite similar ages and weights in subjects with and without ostephytes, those with osteophytes had greater spinal density (1.34 vs. 1.17 g/cm2; P less than 0.001), and there was a strong correlation between osteophyte severity and spinal density (r = 0.41; P less than 0.00001). Proximal femoral density was not different in those with and without osteophytes. The distribution of osteophytes in this population was not random, and as a result, the presence of osteophytes obscured the the relationship of bone density to age as well as the comparison of hospitalized to normal men. Vascular calcification had a minimal effect on vertebral density. In summary, osteophytic calcification exerted an important influence on the measurement of spinal bone density in men. This effect should be considered in both clinical and research applications of integral vertebral density measures.

  9. Factors influencing gelation properties of corn germ proteins.

    PubMed

    Sun, Xiang Dong; Shi, Dan; Lan, Yu; Yao, Xin Miao; Zhang, Rui Ying; Zhang, Ying Lei; Su, Ping; Shan, Hong

    2017-03-07

    As a by-product of the oil industry, corn germ meal is mainly applied as a high-protein ingredient in animal feeds, without any application of the specific functional properties of corn germ protein (CGP). Factors influencing the gelation properties of CGP in relation to its dynamic rheology are still unclear owing to limited information. CGP concentrate was recovered by the isoelectric precipitation method, and factors affecting its gelation properties were investigated using a rheometer. A weak gel formed at natural pH with 0.3 mol L(-1) NaCl, and the minimum gel-forming concentration was observed at 150 g kg(-1) . Higher CGP protein concentrations induced stiffer gels, and linear relationships were found between protein concentration and gel stiffness (G') as well as between protein concentration and gel viscosity (G″). Lower heating and cooling rate promoted the formation of stiffer gels. CGP gelation was both NaCl- and pH-dependent. Sodium tripolyphosphate significantly increased gel stiffness with increasing concentration. No difference in gel elasticity (tanδ) was observed with the inclusion of various concentrations of sodium tripolyphosphate or sodium polyphosphate. Heating and cooling rate, NaCl, protein concentration, pH and phosphates all impact the gel-forming ability of CGP concentrate. Desired gel properties can be obtained through adjustment of these factors. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  10. 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.

  11. 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.

  12. Calcification of Vascular Smooth Muscle Cells and Imaging of Aortic Calcification and Inflammation

    PubMed Central

    Hutcheson, Joshua D.; Burke, Megan F.; Martyn, Trejeeve; Thayer, Timothy E.; Shakartzi, Hannah R.; Buswell, Mary D.; Tainsh, Robert E.; Yu, Binglan; Bagchi, Aranya; Rhee, David K.; Wu, Connie; Derwall, Matthias; Buys, Emmanuel S.; Yu, Paul B.; Bloch, Kenneth D.; Aikawa, Elena; Bloch, Donald B.; Malhotra, Rajeev

    2016-01-01

    Cardiovascular disease is the leading cause of morbidity and mortality in the world. Atherosclerotic plaques, consisting of lipid-laden macrophages and calcification, develop in the coronary arteries, aortic valve, aorta, and peripheral conduit arteries and are the hallmark of cardiovascular disease. In humans, imaging with computed tomography allows for the quantification of vascular calcification; the presence of vascular calcification is a strong predictor of future cardiovascular events. Development of novel therapies in cardiovascular disease relies critically on improving our understanding of the underlying molecular mechanisms of atherosclerosis. Advancing our knowledge of atherosclerotic mechanisms relies on murine and cell-based models. Here, a method for imaging aortic calcification and macrophage infiltration using two spectrally distinct near-infrared fluorescent imaging probes is detailed. Near-infrared fluorescent imaging allows for the ex vivo quantification of calcification and macrophage accumulation in the entire aorta and can be used to further our understanding of the mechanistic relationship between inflammation and calcification in atherosclerosis. Additionally, a method for isolating and culturing animal aortic vascular smooth muscle cells and a protocol for inducing calcification in cultured smooth muscle cells from either murine aortas or from human coronary arteries is described. This in vitro method of modeling vascular calcification can be used to identify and characterize the signaling pathways likely important for the development of vascular disease, in the hopes of discovering novel targets for therapy. PMID:27284788

  13. 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

  14. 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.

  15. Soil physical properties influence "black truffle" fructification in plantations.

    PubMed

    Alonso Ponce, Rafael; Ágreda, Teresa; Águeda, Beatriz; Aldea, Jorge; Martínez-Peña, Fernando; Modrego, María Pilar

    2014-04-01

    Although the important effects of pH and carbonate content of soils on "black truffle" (Tuber melanosporum) production are well known, we poorly understand the influence of soil physical properties. This study focuses on physical soil characteristics that drive successful production of black truffles in plantations. Seventy-eight Quercus ilex ssp. ballota plantations older than 10 years were studied in the province of Teruel (eastern Spain). Soil samples were analyzed for various edaphic characteristics and to locate T. melanosporum ectomycorrhizae. The influence of cultivation practices, climatic features, and soil properties on sporocarp production was assessed using multivariate analyses. Low contents of fine earth and silt and high levels of bulk density, clay content, and water-holding capacity appear to promote fructification. Watering is also highly positive for truffle fructification. We develop and discuss a logistic model to predict the probability of truffle fructification in field sites under consideration for truffle plantation establishment. The balance between water availability and aeration plays a crucial role in achieving success in black truffle plantations.

  16. Pseudohypoparathyroidism with basal ganglia calcification

    PubMed Central

    Song, Cheng-Yuan; Zhao, Zhen-Xiang; Li, Wei; Sun, Cong-Cong; Liu, Yi-Ming

    2017-01-01

    Abstract Rationale: Parkinsonism can be secondary to many internal diseases, in some certain conditions, it seems that the clinical manifestations of parkinsonism presenting reversible. We report a case of patient with parkinsonism secondary to pseudohypoparathyroidism, who improved markedly after the supplement of serum calcium. Patient concerns and diagnoses: A 52-year-old woman with acute parkinsonism was diagnosed as pseudohypoparathyroidism after the conducting of brain computed tomography, laboratory examinations, and gene detection. The son of the patient was also examined and was diagnosed as pseudohypoparathyroidism, who had ever complained of the history of epilepsy. The clinical manifestations of parkinsonism of the patient was reevaluated after the supplement of serum calcium according to the diagnosis. Interventions and outcomes: The brain computed tomography revealed the basal ganglia calcification of the patient, accompanying by serum hypocalcemia and hyperphosphatemia. Loss of function mutation also confirmed the diagnosis. Five days after the therapy targeting at correction of serum hypocalcemia, the patient improved greatly in dyskinesia. Lessons: This study reported a patient presenting as acute reversible parkinsonism, who was finally diagnosed as pseudohypoparathyroidism. It indicated us that secondary parkinsonism should be carefully differentiated for its dramatic treatment effect. And the family history of seizures might be an indicator for the consideration of pseudohypoparathyroidism. PMID:28296742

  17. 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.

  18. Brain Mitochondrial Drug Delivery: Influence of Drug Physicochemical Properties

    PubMed Central

    Durazo, Shelley A.; Kadam, Rajendra S.; Drechsel, Derek; Patel, Manisha

    2017-01-01

    Purpose To determine the influence of drug physicochemical properties on brain mitochondrial delivery of 20 drugs at physiological pH. Methods The delivery of 8 cationic drugs (beta-blockers), 6 neutral drugs (corticosteroids), and 6 anionic drugs (non-steroidal anti-inflammatory drugs, NSAIDs) to isolated rat brain mitochondria was determined with and without membrane depolarization. Multiple linear regression was used to determine whether lipophilicity (Log D), charge, polarizability, polar surface area (PSA), and molecular weight influence mitochondrial delivery. Results The Log D for beta-blockers, corticosteroids, and NSAIDs was in the range of −1.41 to 1.37, 0.72 to 2.97, and −0.98 to 2, respectively. The % mitochondrial uptake increased exponentially with an increase in Log D for each class of drugs, with the uptake at a given lipophilicity obeying the rank order cationic>anionic>neutral. Valinomycin reduced membrane potential and the delivery of positively charged propranolol and betaxolol. The best equation for the combined data set was Log % Uptake=0.333 Log D+ 0.157 Charge – 0.887 Log PSA+2.032 (R2=0.738). Conclusions Drug lipopohilicity, charge, and polar surface area and membrane potential influence mitochondrial drug delivery, with the uptake of positively charged, lipophilic molecules being the most efficient. PMID:21796482

  19. Brain mitochondrial drug delivery: influence of drug physicochemical properties.

    PubMed

    Durazo, Shelley A; Kadam, Rajendra S; Drechsel, Derek; Patel, Manisha; Kompella, Uday B

    2011-11-01

    To determine the influence of drug physicochemical properties on brain mitochondrial delivery of 20 drugs at physiological pH. The delivery of 8 cationic drugs (beta-blockers), 6 neutral drugs (corticosteroids), and 6 anionic drugs (non-steroidal anti-inflammatory drugs, NSAIDs) to isolated rat brain mitochondria was determined with and without membrane depolarization. Multiple linear regression was used to determine whether lipophilicity (Log D), charge, polarizability, polar surface area (PSA), and molecular weight influence mitochondrial delivery. The Log D for beta-blockers, corticosteroids, and NSAIDs was in the range of -1.41 to 1.37, 0.72 to 2.97, and -0.98 to 2, respectively. The % mitochondrial uptake increased exponentially with an increase in Log D for each class of drugs, with the uptake at a given lipophilicity obeying the rank order cationic>anionic>neutral. Valinomycin reduced membrane potential and the delivery of positively charged propranolol and betaxolol. The best equation for the combined data set was Log % Uptake = 0.333 Log D + 0.157 Charge - 0.887 Log PSA + 2.032 (R(2) = 0.738). Drug lipopohilicity, charge, and polar surface area and membrane potential influence mitochondrial drug delivery, with the uptake of positively charged, lipophilic molecules being the most efficient.

  20. Imaging Patterns of Intratumoral Calcification in the Abdominopelvic Cavity

    PubMed Central

    Yu, Mi Hye; Park, Hee Sun; Jung, Sung Il; Jeon, Hae Jeong

    2017-01-01

    Intratumoral calcification is one of the most noticeable of radiologic findings. It facilitates detection and provides information important for correctly diagnosing tumors. In the abdominopelvic cavity, a wide variety of tumors have calcifications with various imaging features, though the majority of such calcifications are dystrophic in nature. In this article, we classify the imaging patterns of intratumoral calcification according to number, location, and morphology. Then, we describe commonly-encountered abdominopelvic tumors containing typical calcification patterns, focusing on their differentiable characteristics using the imaging patterns of intratumoral calcification. PMID:28246512

  1. Influence of dimethyl formamide pulping of bagasse on pulp properties.

    PubMed

    Rezayati-Charani, P; Mohammadi-Rovshandeh, J; Hashemi, S J; Kazemi-Najafi, S

    2006-12-01

    Organosolv pulping of bagasse was conducted following a central composite design using a two-level factorial plan involving three pulping variables (temperature: 190-210 degrees C, time: 120-180 min, organic solvent charge: 40-60% dimethyl formamide). Responses of pulp properties (yield and holocellulose, alpha-cellulose, kappa number, ash and ethanol-dichloromethane extractives contents) and the pH of the resulting wastewater to the process variables were analyzed using statistical software (MINITAB). Main factor analysis revealed that optimum pulp has the following characteristics: 82.7% (yield), 92.9 (kappa number), 95.84% (holocellulose), 83.53% (alpha-cellulose), 1.403% (ash), 2.562% (ethanol-dichloromethane extractives contents) and 6.39 (pH). These results showed that acceptable properties of pulps could be gained at 200-210 degrees C for 150 min and 40-60% DMF. Based on these results, this method could be used for pulping of bagasse equivalent NSSC concerning high yield at a fixed kappa number. In addition, bagasse could be pulped with ease to approximately 55% yield with a kappa number approximately 31. Numerical analyses showed that cooking temperature had the greatest influence on properties of obtained pulps within the DMF concentrations and cooking time as cooking variables.

  2. 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.

  3. Influence of Grain Boundary Properties and Orientation on Void Nucleation

    SciTech Connect

    Fensin, Saryu Jindal

    2016-03-01

    For ductile metals, dynamic fracture during shock loading is thought to occur through void nucleation, growth, and then coalescence that leads to material failure. Particularly for high purity metals, it has been observed by numerous investigators that, under incipient spall conditions, voids appear to heterogeneously nucleate at some grain boundaries, but not others. Several factors can affect the void nucleation stress at a grain boundary, such as grain boundary structure, orientation with respect to the loading direction, energy and excess volume, in addition to its interactions with dislocations. In this work, we focus on the influence of loading direction with respect to the grain boundary plane and grain boundary properties such as energy and excess volume on the stress required for void nucleation of a grain boundary, in copper from moleculardynamics simulations. Flyer plate simulations were carried out for four boundary types with different energies and excess volumes. These boundaries were chosen as model systems to represent various boundaries observed in “real” materials. Simulations indicate that there is no direct correlation between the void nucleation stress at a boundary and either its energy and excess volume. This result suggests that average properties of grain boundaries alone are not sufficient indicators of the spall strength of a boundary and perhaps local boundary properties need to be taken into account in order to predict its susceptibility to void nucleation for broad ranges of materials. We also present both experimental and simulation results corresponding to the affect of orientation on void nucleation.

  4. 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.

  5. 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

  6. 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.

  7. Influence of fuel chemical properties on gas turbine combustors

    NASA Technical Reports Server (NTRS)

    Rosfjord, T. J.

    1984-01-01

    In an attempt to rigorously study the fuel chemical property influence, UTRC (United Technologies Research Center) (under contract to NASA Lewis Research Center) has conducted an experimental program using 25 test fuels. The burner was a 12.7 cm dia cylindrical device consisting of six sheet metal louvers. A single pressure atomizing injector and air swirler were centrally mounted with the conical dome. Fuel physical properties were de-emphasized by using fuel injectors which produced highly atomized, and hence rapidly vaporizing sprays. A substantial fuel spray characterization effort was conducted to allow selection of nozzles which assured that such sprays were achieved for all fuels. The fuels were specified to cover the following wide ranges of chemical properties: hydrogen, 9.1 to 15 (wt) pct; total aromatics, 0 to 100 (vol) pct; and naphthalene, 0 to 30 (vol) pct. They included standard fuel (e.g., Jet A, JP4), specialty products (e.g., decalin, xylene tower bottoms) and special fuel blends. Included in this latter group were six, 4-component blends prepared to achieve parametric variations in fuel hydrogen, total aromatics and naphthalene contents.

  8. 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

  9. 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.

  10. Idiopathic Arterial Calcification of Infancy: Case Report

    PubMed Central

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

    2015-01-01

    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. PMID:27252793

  11. [Sturge-Weber syndrome with atypical calcifications].

    PubMed

    Prieto, M L; de Juan, J; Antón, M; Roiz, C; Crespo, M

    1997-09-01

    The syndrome, or disease, or Sturge Weber (SSW) is a neuro-ectodermic disorder of unknown incidence, sporadic presentation and specific sex incidence. It is characterized by the presence of a flat, facial angioma which affects at least the first branch of the trigeminal nerve, association with ipsilateral leptomeningeal vascular anomalies, one or more symptoms (epilepsy, hemiparesia, hemiplegia or mental retardation) and ipsilateral vascular lesions of the choroid which lead to glaucoma. As a consequence of lepto-meningeal involvement, homolateral cerebral hemi-atrophy develops together with cortico-subcortical calcifications with a characteristic "railway line" appearance. We present the case of a six month old girl with a flat port wine angioma on the left half of her face, including three branches of the trigeminal nerve and the left half of her body. She had partial motor crises of the right leg. On the cranial CT there were left periventricular calcifications and calcifications of the choroid plexus. Gadolinium-MR showed signs of left cerebral hemi-atrophy, which was confirmed on the cerebral SPECT (left temporal hypoperfusion). This case is interesting on account of the presence of atypical calcifications, both with regard to the sites and age of presentation. We emphasize the need for cranial CT to rule out the presence of calcifications, (as in this case) not seen on Xray of the skull or on MR. We favour the use of cerebral SPECT as a complementary diagnostic technique.

  12. Polyethylene glycol-grafted bovine pericardium: a novel hybrid tissue resistant to calcification.

    PubMed

    Vasudev, S C; Chandy, T

    1999-02-01

    Calcification is a frequent cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde pretreated bovine pericardium (GATBP). An investigation was made of the grafting of different molecular weight polyethylene glycol (PEG 600, 1500, 4000 and 6000) via glutaraldehyde (GA) linkages to bovine pericardium (BP) and of their stability and calcification. The process of the calcification profile was studied by in vitro experiments via incubating pericardial samples in a metastable solution of calcium phosphate. Calcification of bovine pericardium grafted with PEG 6000 was significantly decreased compared to low molecular weight PEG grafts or Sodium dodecyl sulphate- (SDS) and GA-treated tissues. The mechanical properties of these modified tissues after enzyme (Trypsin) digestion and calcification were investigated. The biocompatibility aspects of grafted tissues were also established by monitoring the platelet adhesion, octane contact angle and water of hydration. PEG 6000-grafted tissues retained the maximum strength in trypsin buffer and calcium phosphate solutions. Scanning electron micrographs revealed that the PEG-grafted bovine pericardium had substantially inhibited the platelet-surface attachment and their spreading. It is conceivable that high molecular weight polyethylene glycol-grafted pericardium (a hybrid tissue) may be a suitable calcium-resistant material for developing prosthetic valves due to their stability and biocompatibility.

  13. Factors influencing meat emulsion properties and product texture: A review.

    PubMed

    Santhi, D; Kalaikannan, A; Sureshkumar, S

    2017-07-03

    Emulsion-based meat products play an important role in modern meat industry. Though meat batters have been prepared traditionally since long back in the history, the scientific principles and the knowhow are significantly important in the case of commercial products. In India, the market for emulsion meat products is gaining importance in the recent years and the native producers are in critical need for the scientific basis of production of emulsion meat products with better yield, good sensory qualities and nutrition. Hence, this review will throw light on some of the important factors which influence the properties of meat emulsion such as stability, structure, etc. and the product texture and yield as the revealed by past researches which will be useful to the meat processors in their practical application in preparing meat emulsion products.

  14. Gastric carcinoma with psammomatous calcification: report of a case, with reference to calculogenesis

    SciTech Connect

    Murayama, H.; Kamio, A.; Imai, T.; Kikuchi, M.

    1982-02-15

    A case of gastric adenocarcinoma with argyrophilic property and psammomatous calcification is reported. Histologically, the psammoma bodies are found most frequently within the glandular lumina. Electron microscopy, however, reveals that calcium first appears within the cytoplasm of tumor cells. Electron probe x-ray microanalysis demonstrates calcium and phosphorus in granular or floccular osmiophilic deposits found in intracytoplasmic electronlucent zones of tumor cells. By x-ray diffractometry, the calcium component is presumed to be hydroxyappatite (Ca5(PO4)3.(OH). The findings strongly support the view of the intracytoplasmic origin of psammomatous calcification. The tumor yielded a parathyroid hormone (PTH)-like substance, and a possible relationship between this substance and psammomatous calcification is spectulated.

  15. Gallium-67 uptake in the lung associated with metastatic calcification

    SciTech Connect

    Auerbach, J.M.; Ho, J.

    1981-03-01

    The case of a patient in whom pulmonary calcification appeared rapidly, accompanied by diffuse gallium-67 uptake in the lungs is reported. This finding, associated with metastatic calcification in the absence of inflammation or neoplasm, has not been previously reported.

  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. Apoptosis regulates human vascular calcification in vitro: evidence for initiation of vascular calcification by apoptotic bodies.

    PubMed

    Proudfoot, D; Skepper, J N; Hegyi, L; Bennett, M R; Shanahan, C M; Weissberg, P L

    2000-11-24

    The mechanisms involved in the initiation of vascular calcification are not known, but matrix vesicles, the nucleation sites for calcium crystal formation in bone, are likely candidates, because similar structures have been found in calcified arteries. The regulation of matrix vesicle production is poorly understood but is thought to be associated with apoptotic cell death. In the present study, we investigated the role of apoptosis in vascular calcification. We report that apoptosis occurs in a human vascular calcification model in which postconfluent vascular smooth muscle cell (VSMC) cultures form nodules spontaneously and calcify after approximately 28 days. Apoptosis occurred before the onset of calcification in VSMC nodules and was detected by several methods, including nuclear morphology, the TUNEL technique, and external display of phosphatidyl serine. Inhibition of apoptosis with the caspase inhibitor ZVAD.fmk reduced calcification in nodules by approximately 40%, as measured by the cresolphthalein method and alizarin red staining. In addition, when apoptosis was stimulated in nodular cultures with anti-Fas IgM, there was a 10-fold increase in calcification. Furthermore, incubation of VSMC-derived apoptotic bodies with (45)Ca demonstrated that, like matrix vesicles, they can concentrate calcium. These observations provide evidence that apoptosis precedes VSMC calcification and that apoptotic bodies derived from VSMCs may act as nucleating structures for calcium crystal formation.

  18. 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

    2015-08-18

    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.

  19. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Bisphosphonates for vascular calcification].

    PubMed

    Kurozumi, Akira; Okada, Yosuke; Nakano, Kazuhisa; Tanaka, Yoshiya

    2015-05-01

    In Japan, the number of diabetes mellitus and chronic kidney disease patients is increasing yearly. Vascular calcification is prevailing in patients suffering from diabetes mellitus and/or chronic kidney disease, and carries a poor prognosis. However, the effective treatment for suppressing the progression of vascular calcification has not been established. On the other hand, treatment of osteoporosis has advanced dramatically as the details of the mechanism become clearer. Bisphosphonates, which are inhibitors of bone resorption that are widely used to treat osteoporosis, also inhibit cholesterol biosynthesis, differentiation of macrophage to foam cell, differentiation of smooth muscle cells to osteoblast-like cells in certain stimuli during calcification processes of vessels. These findings extend the link between bone remodeling and vascular calcification, opening perspectives toward novel therapeutic strategies. We herein review recent findings about effectiveness of bisphosphonates for vascular calcification with our data. Here we will review recent advances in the researches of treatment of vascular calcification and present our findings that the bisphosphonate is useful in prevention of vascular calcification.

  20. 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

  1. [Influences of pine needles physiological properties on the PAH accumulation].

    PubMed

    Yang, Ping; Wang, Zhen; Chen, Jing-Wen; Tian, Fu-Lin; Ge, Lin-Ke

    2008-07-01

    The lipid contents, specific surface areas and stomata density of two kinds of pine (Cedrus deodar and Pinus thunbergii) needles were determined simultaneously with the levels of polycyclic aromatic hydrocarbons (PAHs). The influences of the physiological properties of two species on the accumulation of PAHs in pine needles were investigated. The PAH concentrations in Cedrus deodar needles are higher than that in Pinus thunbergii needles, and the average total PAH concentrations (PAHs) in two species are (1 101 +/- 692) ng/g and (518 +/- 339) ng/g, respectively. The capabilities of accumulating PAHs for two species are different. The lipid content is the principal factor influencing the levels of pine needle PAHs. In Cedrus deodar and Pinus thunbergii needles, 3-ring (> 56%) and 4-ring (> 31%) PAHs make up large proportions of sigma PAHs. The accumulation capabilities of pine needles for 3-ring PAHs are greater than 4-ring PAHs, and the concentrations of 3-ring PAHs are about two times of those of 4-ring PAHs. There are no significant correlations between the levels of 5- and 6-ring PAHs and lipid contents for two species. For two species, the correlations between lipid contents and specific surface areas are different, which results in the contrary correlations between the PAH levels and specific surface areas for Cedrus deodar and Pinus thunbergii. Specific surface areas and stomata density affect the levels of 5- and 6-ring PAHs in pine needles significantly.

  2. Urea-containing moisturizers influence barrier properties of normal skin.

    PubMed

    Loden, M

    1996-02-01

    Moisturizers are used in the treatment of dry skin, both clinically and in cosmetic products. In the present study the influence of different moisturizers on the normal skin barrier properties was evaluated by measuring transepidermal water loss (TEWL) and skin capacitance. In addition, the skin reactivity to a topically applied surfactant, sodium lauryl sulphate (SLS), following the use of the moisturizers was examined. The skin reaction was assessed visually and by measuring TEWL and superficial blood flow. Treatment with two urea-containing moisturizers for 10 and 20 days decreased TEWL. The irritant reactions after exposure to SLS were also significantly decreased after prior treatment for 20 days with the urea-containing moisturizers. In a double-blind vehicle-controlled part of the study, urea was found to decrease the skin susceptibility to SLS after only three applications. However, this decrease in skin reactivity was not preceded by a reduction in TEWL. Skin capacitance increased after three applications of urea-containing moisturizers and was still increased after 10 days, but not after 20 days of this treatment. Treatment for 20 days with two moisturizers without urea did not influence either TEWL or the susceptibility to irritation from SLS, but it increased the skin capacitance significantly. The mechanism underlying these changes is not known. The lower degree of SLS-induced irritation in the skin treated previously with urea-containing moisturizers may be of clinical relevance in reducing contact dermatitis from irritant stimuli.

  3. Influence of luminosity bursts on properties of protostellar disks

    NASA Astrophysics Data System (ADS)

    Vorobyov, E. I.; Pavlyuchenkov, Ya. N.; Trinkl, P.

    2014-08-01

    A (2+ 1)-dimensional numerical model for the formation and evolution of young stellar objects with sub-solar masses is presented. The numerical hydrodynamicall code describing the formation and evolution of a protostellar disk in a two-dimensional approximation is supplemented by one-dimensional code for the evolution of the star and an algorithm for establishing the vertical structure of the disk. This code is used to investigate the influence of luminosity bursts with intensities similar to those observed in FU Orionis objects (FUors) on the properties and thermal balance of protostellar disks. A model with gravitational instability and fragmentation of the disk, with subsequent migration of the fragments onto the protostar, is used as a basic model for FUors. Typical FUor bursts ( L ˜ 100 L ⊙) can appreciably influence the thermal balance of their disks and parent envelopes, leading to an increase in the disk temperature by more than a factor of two. On the other hand, massive fragments in the disk are only weakly perturbed by such bursts, partially due to screening by the disk and partially due to their high temperature brought about by adiabatic heating. Apart from massive fragments, the characteristic thermal time scales are appreciably shorter than the dynamical time scales throughout the radial extent of the disk and envelope; this enables the use of a stationary radiative-transfer equation when determining the vertical structure of the disk.

  4. The influence of hair lipids in ethnic hair properties.

    PubMed

    Martí, M; Barba, C; Manich, A M; Rubio, L; Alonso, C; Coderch, L

    2016-02-01

    Biochemical studies have mainly focused on the composition of hair. African hair exhibited lower moisturization and less radial swelling when flushing with water compared with Asian or Caucasian hair, and they assumed a possible lipid differentiation among human populations. This study consists in the lipid characterization of different ethnic hairs (Caucasian, Asian and African hairs) and the influence of these lipids in different hair properties such as humidity and mechanical properties. Evaluation of water sorption and desorption of the different ethnic hairs and with and without lipids is also studied mainly to determine permeation changes of the keratin fibres. Extractions of exogenous and endogenous lipids with different organic solvents were performed; lipid analysis and its quantification using thin-layer chromatography coupled to an automated flame ionization detector (TLC/FID) were performed. Absorption and desorption curves were obtained in a thermogravimetric balance equipped with a controlled humidity chamber, the Q5000SA Sorption Analyzer (TA Instruments, New Castle, IL, U.S.A.). Also, mechanical properties (breaking stress and breaking elongation) were analysed using a computer programmable dynamometer (Instron 5500R). Lipid extraction showed the highest amount of total lipids for the African hair which may come from external sebaceous lipids compared with Asian or Caucasian hair. Caucasian fibres were found to be the most hydrated fibre, and a decrease in moisture was found in the extracted fibres, again, which is more important for the Caucasian hair. A superior lineal mass was found for the Asian fibres which supported their higher strength. The results obtained from the analysis of the mechanical properties of delipidized fibres indicate a surprising increase in the strength of African and Caucasian fibres. Perhaps this increase in strength could be related to the humidity decrease in lipid-extracted hair fibres. Results of water uptake and

  5. 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.

  6. Influence of cell properties on rheological characterization of microalgae suspensions.

    PubMed

    Zhang, Xinru; Jiang, Zeyi; Chen, Liang; Chou, Aihui; Yan, Hai; Zuo, Yi Y; Zhang, Xinxin

    2013-07-01

    The influences of algal cell size and surface charge on rheological properties of microalgae suspensions were investigated. The effective viscosity of two microalgae suspensions, i.e., the freshwater Chlorella sp. and the marine Chlorella sp., was measured as a function of their volume fractions in the range of 0.70-4.31%. The hydrodynamic diameters of the freshwater Chlorella sp. and the marine Chlorella sp. were measured to be 3.13 and 6.00 μm, respectively. The Zeta potentials of these two algal cells were measured to be -23.73 and -81.81 mV, respectively. The intrinsic viscosities of these two microalgae suspensions were further determined to be 24.7 and 16.1, respectively. Combining with theoretical models, these results indicated that the algal cell size has a predominant effect over cell surface charge in affecting rheological properties of microalgae suspensions. Smaller algal cells result in a higher effective viscosity of the microalgae suspension.

  7. Thermophysical properties of hydrophobised lime plasters - The influence of ageing

    NASA Astrophysics Data System (ADS)

    Pavlíková, Milena; Zemanová, Lucie; Pavlík, Zbyšek

    2017-07-01

    The building envelope is a principal responsible for buildings energy loses. Lime plasters as the most popular finishing materials of historical buildings and culture monuments influence the thermal behaviour as well as construction material of masonry. On this account, the effect of ageing on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime plaster is tested. The ageing is accelerated with controlled carbonation process to simulate the final plasters properties. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity are experimentally assessed using a transient impulse method. The obtained data revealed the significant changes of the both studied thermal parameters in the dependence on plasters composition and age. The assessed material parameters will be stored in a material database, where will find use as an input data for computational modelling of heat transport in this type of porous building materials and evaluation of energy-savings and sustainability issues.

  8. 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

  9. [Sclerochoroidal calcification associated with hypovitaminosis D].

    PubMed

    Sierra-Rodríguez, M A; Bailez Fidalgo, C; Sáenz-Francés, F; Gonzalez Romero, J C; Muñoz Bellido, L

    2014-07-01

    A 69 year-old woman was referred for a routine visit, during which funduscopy revealed white-yellow subretinal lesions in the superotemporal mid-periphery of both eyes. A and B scan ultrasound showed hyperechogenic lesions located at scleral and choroidal level. Computed tomography revealed posterolateral sclerochoroidal calcifications. Metabolic studies showed a severe vitamin D deficiency with no other remarkable findings. Sclerochoroidal calcifications are an infrequent finding that occur as a result of calcium deposit at scleral and choroidal level. They have a characteristic clinical picture and are idiopathic in most cases, but may be associated with some systemic diseases, such as calcium and phosphorous metabolic disorders; this fact warrants a thorough metabolic study. We report a case of bilateral sclerochoroidal calcifications associated with severe vitamin D deficiency with no other significant metabolic findings. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  10. 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.

  11. 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

  12. Species-specific responses to climate change and community composition determine future calcification rates of Florida Keys reefs.

    PubMed

    Okazaki, Remy R; Towle, Erica K; van Hooidonk, Ruben; Mor, Carolina; Winter, Rivah N; Piggot, Alan M; Cunning, Ross; Baker, Andrew C; Klaus, James S; Swart, Peter K; Langdon, Chris

    2017-03-01

    Anthropogenic climate change compromises reef growth as a result of increasing temperatures and ocean acidification. Scleractinian corals vary in their sensitivity to these variables, suggesting species composition will influence how reef communities respond to future climate change. Because data are lacking for many species, most studies that model future reef growth rely on uniform scleractinian calcification sensitivities to temperature and ocean acidification. To address this knowledge gap, calcification of twelve common and understudied Caribbean coral species was measured for two months under crossed temperatures (27, 30.3 °C) and CO2 partial pressures (pCO2 ) (400, 900, 1300 μatm). Mixed-effects models of calcification for each species were then used to project community-level scleractinian calcification using Florida Keys reef composition data and IPCC AR5 ensemble climate model data. Three of the four most abundant species, Orbicella faveolata, Montastraea cavernosa, and Porites astreoides, had negative calcification responses to both elevated temperature and pCO2 . In the business-as-usual CO2 emissions scenario, reefs with high abundances of these species had projected end-of-century declines in scleractinian calcification of >50% relative to present-day rates. Siderastrea siderea, the other most common species, was insensitive to both temperature and pCO2 within the levels tested here. Reefs dominated by this species had the most stable end-of-century growth. Under more optimistic scenarios of reduced CO2 emissions, calcification rates throughout the Florida Keys declined <20% by 2100. Under the most extreme emissions scenario, projected declines were highly variable among reefs, ranging 10-100%. Without considering bleaching, reef growth will likely decline on most reefs, especially where resistant species like S. siderea are not already dominant. This study demonstrates how species composition influences reef community responses to climate change

  13. [Arterial calcification and risk of cardiovascular events in diabetes mellitus].

    PubMed

    Iwai, Kunimitu; Morimoto, Shigeto

    2010-11-01

    The cohort studies reported the subclinical vascular calcification including atheroslerosis starts during prediabetic state characterized by impaired fasting glucose. In the cardiovascular systems of diabetes mellitus there is an original mechanism to induce the medial calcification other than intimal calcification observed in the classical atherosclerosis. This is characterized as the ectipic osteogenesis induced by paracrine signals from inflammatory lesions in the adventitia. On the other hand, many internal systems have been discovered to inhibit vascular calcification.

  14. Extensive pelvic calcification in association with ovarian serous cystadenofibroma.

    PubMed

    Hayes, Stephen J; Misfar, Nasira; Slade, Richard; Mamtora, Hari; Wilson, Godfrey

    2008-08-01

    We describe the first reported case of extensive calcification seen in association with serous cystadenofibroma of the ovary, illustrating that calcification in the female genital tract may be extensive in nature, presenting in a fashion that is not entirely typical of dystrophic or metastatic calcification. This case demonstrates that extensive calcification within the pelvis should be interpreted with caution, as it may not represent disseminated malignancy.

  15. 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.

  16. [Vascular Calcification - Pathological Mechanism and Clinical Application - . Vascular calcification in chronic kidney disease-mineral and bone disorder (CKD-MBD)].

    PubMed

    Omata, Momoyo; Fukagawa, Masafumi; Kakuta, Takatoshi

    2015-05-01

    Chronic kidney disease-mineral and bone disorder (CKD-MBD), is sequential pathophysiology that starts in the very early stages of CKD. Three major aspects of CKD-MBD are laboratory abnormalities, bone abnormalities and vascular calcification. In dialysis patients, the prevalence of death due to cardiovascular disease accounts for more than 40% of all-cause mortality. Therefore, arteriosclerosis with vascular calcification may be an important pathophysiological mechanism in the development of cardiovascular disease. Vascular calcification is known to be an important risk factor influencing mortality in CKD patients. A number of studies have suggested a close association between serum FGF23 concentration and the risks of mortality, cardiovascular disease vascular calcification as well as CKD progression. Renal insufficiency leads to decline in klotho level and impaired phosphate excretion. However serum phosphate levels are maintained in the normal range by up regulation of FGF23 and PTH in early CKD stage. Early treatment intervention is necessary to improve the prognosis of the CKD patient.

  17. 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.

  18. Arterial ageing: from endothelial dysfunction to vascular calcification.

    PubMed

    Tesauro, M; Mauriello, A; Rovella, V; Annicchiarico-Petruzzelli, M; Cardillo, C; Melino, G; Di Daniele, N

    2017-05-01

    Complex structural and functional changes occur in the arterial system with advancing age. The aged artery is characterized by changes in microRNA expression patterns, autophagy, smooth muscle cell migration and proliferation, and arterial calcification with progressively increased mechanical vessel rigidity and stiffness. With age the vascular smooth muscle cells modify their phenotype from contractile to 'synthetic' determining the development of intimal thickening as early as the second decade of life as an adaptive response to forces acting on the arterial wall. The increased permeability observed in intimal thickening could represent the substrate on which low-level atherosclerotic stimuli can promote the development of advanced atherosclerotic lesions. In elderly patients the atherosclerotic plaques tend to be larger with increased vascular stenosis. In these plaques there is a progressive accumulation of both lipids and collagen and a decrease of inflammation. Similarly the plaques from elderly patients show more calcification as compared with those from younger patients. The coronary artery calcium score is a well-established marker of adverse cardiovascular outcomes. The presence of diffuse calcification in a severely stenotic segment probably induces changes in mechanical properties and shear stress of the arterial wall favouring the rupture of a vulnerable lesion in a less stenotic adjacent segment. Oxidative stress and inflammation appear to be the two primary pathological mechanisms of ageing-related endothelial dysfunction even in the absence of clinical disease. Arterial ageing is no longer considered an inexorable process. Only a better understanding of the link between ageing and vascular dysfunction can lead to significant advances in both preventative and therapeutic treatments with the aim that in the future vascular ageing may be halted or even reversed. © 2017 The Association for the Publication of the Journal of Internal Medicine.

  19. Influence of molar ratios on properties of magnesium oxychloride cement

    SciTech Connect

    Li Zongjin . E-mail: zongjin@ust.hk; Chau, C.K.

    2007-06-15

    A parametric study has been conducted to investigate the influences of the molar ratios of MgO/MgCl{sub 2} and H{sub 2}O/MgCl{sub 2} on the properties of magnesium oxychloride (MOC) cement. By an integrated assessment of the experimental studies of strength development and X-ray diffractograms, together with application of the relevant phase diagram, it is recognized that the molar ratios of MgO/MgCl{sub 2} and H{sub 2}O/MgCl{sub 2} can significantly affect the properties of MOC cement. For a MOC cement paste possessing a dominance of 5MgO.MgCl{sub 2}.8H{sub 2}O (phase 5) crystals, the molar ratios of MgO/MgCl{sub 2} of 11-17 and H{sub 2}O/MgCl{sub 2} of 12-18 are found to be the most favorite ranges for design purpose. The choose of the molar ratio of H{sub 2}O/MgCl{sub 2} is, however, largely depends on the molar ratio of MgO/MgCl{sub 2} mainly for controlling workability of paste. Therefore, the most critical parameter to be selected in the design process is the molar ratio of MgO/MgCl{sub 2}, although the reactivity of the MgO powder is also important. Besides, the molar ratio can also be affected by the reactivity of the MgO powder to be employed. It is believed that a molar ratio of MgO/MgCl{sub 2} of 13, the most suitable one shown in this study, can be used as a starting point in the normal practice.

  20. CD146 Expression Influences Periapical Cyst Mesenchymal Stem Cell Properties.

    PubMed

    Paduano, Francesco; Marrelli, Massimo; Palmieri, Francesca; Tatullo, Marco

    2016-10-01

    Recent studies have identified a new human dental derived progenitor cell population with multi-lineage differentiation potential referred to as human periapical cyst mesenchymal stem cells (hPCy-MSCs). In the present study, we compared two subpopulations of hPCy-MSCs characterised by the low or high expression of CD146 to establish whether this expression can regulate their stem cell properties. Using flow cytometry, we evaluated the stem cell marker profile of hPCy-MSCs during passaging. Furthermore, CD146(Low) and CD146(High) cells were sorted by magnetic beads and subsequently both cell populations were evaluated for differences in their proliferation, self-renewal, stem cell surface markers, stemness genes expression and osteogenic differentiation potential.We found that hPCy-MSCs possessed a stable expression of several mesenchymal stem cell surface markers, whereas CD146 expression declined during passaging.In addition, sorted CD146(Low) cells proliferated significantly faster, displayed higher colony-forming unit-fibroblast capacity and showed higher expression of Klf4 when compared to the CD146(High) subset. Significantly, the osteogenic potential of hPCy-MSCs was greater in the CD146(Low) than in CD146(High) population. These results demonstrate that CD146 is spontaneously downregulated with passaging at both mRNA and protein levels and that the high expression of CD146 reduces the proliferative, self-renewal and osteogenic differentiation potential of hPCy-MSCs. In conclusion, our study demonstrates that changes in the expression of CD146 can influence the stem cell properties of hPCy-MSCs.

  1. Estrogen inhibits vascular calcification via vascular RANKL system: common mechanism of osteoporosis and vascular calcification.

    PubMed

    Osako, Mariana Kiomy; Nakagami, Hironori; Koibuchi, Nobutaka; Shimizu, Hideo; Nakagami, Futoshi; Koriyama, Hiroshi; Shimamura, Munehisa; Miyake, Takashi; Rakugi, Hiromi; Morishita, Ryuichi

    2010-08-20

    Arterial calcification and osteoporosis are associated in postmenopausal women. RANK (the receptor activator of nuclear factor kappaB), RANKL (RANK ligand), and osteoprotegerin are key proteins in bone metabolism and have been found at the site of aortic calcification. The role of these proteins in vasculature, as well as the contribution of estrogen to vascular calcification, is poorly understood. To clarify the mechanism of RANKL system to vascular calcification in the context of estrogen deficiency. RANKL induced the calcification inducer bone morphogenetic protein-2 by human aortic endothelial cells (HAECs) and decreased the calcification inhibitor matrix Gla protein (MGP) in human aortic smooth muscle cells (HASMCs), as quantified by real-time PCR and Western blot analysis. RANKL also induced bone-related gene mRNA expression and calcium deposition (Alizarin red staining) followed by the osteogenic differentiation of HASMCs. Estrogen inhibited RANKL signaling in HAECs and HASMCs mainly through estrogen receptor alpha. Apolipoprotein E-deficient mice fed with Western high-fat diet for 3 months presented atherosclerotic calcification (Oil red and Alizarin red staining) and osteoporosis (microcomputed tomographic analysis) after ovariectomy and increased expression of RANKL, RANK, and osteopontin in atherosclerotic lesion, as detected by in situ hybridization. Estrogen replacement inhibited osteoporosis and the bone morphogenetic protein osteogenic pathway in aorta by decreasing phosphorylation of smad-1/5/8 and increasing MGP mRNA expression. RANKL contributes to vascular calcification by regulating bone morphogenetic protein-2 and MGP expression, as well as bone-related proteins, and is counteracted by estrogen in a receptor-dependent manner.

  2. Reversible vascular calcifications associated with hypervitaminosis D.

    PubMed

    Cirillo, Massimo; Bilancio, Giancarlo; Cirillo, Chiara

    2016-02-01

    A 64-year-old man was hospitalized in 2002 with symptoms of stupor, weakness, and renal colic. The clinical examination indicated borderline hypertension, small masses in the glutei, and polyuria. Laboratory tests evidenced high serum concentrations of creatinine, calcium, and phosphate. Imaging assessments disclosed widespread vascular calcifications, gluteal calcifications, and pelvic ectasia. Subsequent lab tests indicated suppressed serum parathyroid hormone, extremely high serum 25-hydroxy vitamin D, and normal serum 1,25-dihydroxy vitamin D. Treatment was started with intravenous infusion of saline and furosemide due to the evidence of hypercalcemia. Prednisone and omeprazole were added given the evidence of hypervitaminosis D. The treatment improved serum calcium, kidney function, and consciousness. The medical history disclosed recent treatment with exceptionally high doses of slow-release intra-muscular cholecalciferol and the recent excretion of urinary stones. The patient was discharged when it was possible to stop the intravenous treatment. The post-discharge treatment included oral hydration, furosemide, prednisone and omeprazole for approximately 6 months up to complete resolution of the hypercalcemia. The patient came back 12 years later because of microhematuria. Lab tests were normal for calcium/phosphorus homeostasis and kidney function. Imaging tests indicated only minor vascular calcifications. This is the first evidence of reversible vascular calcifications secondary to hypervitaminosis D.

  3. Acute calcific tendinitis of the wrist.

    PubMed

    Torbati, Sam S; Bral, Daniel; Geiderman, Joel M

    2013-02-01

    Acute calcific tendinitis, a benign and self-limiting inflammatory condition commonly seen in the shoulder, is also described in many other tendons, including those in the hand and wrist. When involving the wrist, acute calcific tendinitis is often misdiagnosed and mistaken for infection. We present this case to increase familiarity with this condition to avoid errors in diagnosis resulting in inappropriate treatment with antibiotics or even surgery. A 27-year-old man presented to the Emergency Department with a 2-week history of volar wrist pain, with sudden increase in pain associated with chills and new onset swelling and redness of the wrist. Plain radiographs showed characteristic soft-tissue calcification overlying the insertion of the flexor carpi ulnaris tendon into the wrist. Treatment with ibuprofen and splinting resulted in complete symptom resolution. Acute calcific tendinitis is an important consideration in the differential diagnosis of acute wrist pain. Radiographs are helpful in confirming the diagnosis when symptoms and examination findings are characteristic. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Does glutaraldehyde induce calcification of bioprosthetic tissues?

    PubMed

    Vincentelli, A; Latrémouille, C; Zegdi, R; Shen, M; Lajos, P S; Chachques, J C; Fabiani, J N

    1998-12-01

    Glutaraldehyde has been said to be responsible in part for the calcification of glutaraldehyde-treated tissues after implantation in animals or humans. We investigated whether the origin of the tissue, autologous or heterologous, could have a more prominent role in the process of calcification. Three-month-old sheep received sheep pericardial samples (n = 133) and human pericardial samples (n = 123) implanted subcutaneously. Samples were treated with 0.6% glutaraldehyde for 5, 10, or 20 minutes or 7 days and then rinsed thoroughly before implantation. Samples were then retrieved after 3 months. Calcium content was assessed by spectrophometry. The results show a low calcium content in the autologous group (mean 1.14+/-2.07) and a high calcium content in the heterologous group (mean 38.97+/-26). These results were the same regardless of the duration of the treatment. Glutaraldehyde treatment (0.6%) does not play a significant role in the calcification of glutaraldehyde-treated tissue regardless of the origin, autologous or heterologous, of the tissue. Glutaraldehyde-treated autologous tissues are associated with an incidence of calcification lower than heterologous tissues.

  5. Influence of decavanadate clusters on the rheological properties of gelatin.

    PubMed

    Carn, Florent; Djabourov, Madeleine; Coradin, Thibaud; Livage, Jacques; Steunou, Nathalie

    2008-10-09

    The influence of polyoxovanadate clusters ([H(2)V(10)O(28)](4-)) on the thermo-reversible gelation of porcine skin gelatin solution (type A, M w approximately 40 000 g.mol (-1), pH = 3.4 < isoelectric point (IEP) approximately 8) has been investigated as a function of temperature and vanadate concentration by combining rheology and microcalorimetry. This work shows that the rheological properties of the system depend on electrostatic interactions between [H(2)V(10)O(28)](4-) and positively charged gelatin chains. In a first stage, we describe the renaturation of the gelatin triple helices in the presence of decavanadate clusters. We reveal that, when gelatin chains are in coil conformation (30 degrees C < T < 50 degrees C), the inorganic clusters act as physical cross-linkers that govern the visco-elastic properties of the mixture with an exponential dependence of the (G', G'') modulus with the vanadate concentration. Below 30 degrees C, we show that gelatin triple helix nucleation is slightly favored by the presence of vanadate, but above a helix concentration of 0.012 g.cm (-3), G' is fully governed by the helix concentration. During the melting process, we reveal the non-fully reversible behavior of the vanadate/gelatin rheological properties and the stabilization of gelatin triple helices due to vanadate species until 50 degrees C. This non-reversible character has also been observed in the same experimental conditions with collagen/vanadate solutions. This is the first time that such a stabilization of triple helices has been reported in the case of gelatin hydrogels chemically cross-linked or not. We propose to analyze these results by considering that triple helix aggregates should persist because of decavanadate bridging, that the nucleation of an extended triple helix network may induce a strong modification of the vanadate cross-linker distribution in the system, or both, thus promoting the formation of thermally stable vanadate/gelatin micro-gels in the

  6. Insulin attenuates vascular smooth muscle calcification but increases vascular smooth muscle cell phosphate transport.

    PubMed

    Wang, Cecilia C Low; Sorribas, Victor; Sharma, Girish; Levi, Moshe; Draznin, Boris

    2007-11-01

    Medial artery vascular smooth muscle cell (VSMC) calcification increases the risk of cardiovascular mortality in type 2 diabetes. However, the influence of insulin on VSMC calcification is unclear. We explored the effects of insulin on rat VSMC calcification in vitro and found that in a dose-dependent fashion, insulin attenuates VSMC calcification induced by high phosphate conditions as quantified by the o-cresolphthalein calcium (OCPC) method. In an in vitro model of insulin resistance in which cells are exposed to elevated insulin concentrations and the PI 3-kinase pathway is selectively inhibited, increased VSMC calcification was observed, suggesting that the PI 3-kinase pathway is involved in this attenuating effect of insulin. We postulated that insulin may also have an effect on phosphate or calcium transport in VSMC. We found that insulin increases phosphate transport at 3 and 24 h. This effect was mediated by increased Vmax for phosphate transport but not Km. Because type III sodium-phosphate co-transporters Pit-1 and Pit-2 are found in VSMC, we examined their expression by Western blot and real-time RT-PCR. Insulin stimulates Pit-1 mRNA modestly (*p<0.01 versus control), an effect inhibited by PD98059 but not by wortmannin. Pit-1 protein expression is induced by insulin, an effect also inhibited by PD98059 (*p<0.001 versus insulin alone). Our results suggest a role for insulin in attenuating VSMC calcification which may be disrupted in selective insulin signaling impairment seen in insulin resistance. This effect of insulin contrasts with its effect to induce phosphate transport in VSMC.

  7. NT5E mutations and arterial calcifications.

    PubMed

    St Hilaire, Cynthia; Ziegler, Shira G; Markello, Thomas C; Brusco, Alfredo; Groden, Catherine; Gill, Fred; Carlson-Donohoe, Hannah; Lederman, Robert J; Chen, Marcus Y; Yang, Dan; Siegenthaler, Michael P; Arduino, Carlo; Mancini, Cecilia; Freudenthal, Bernard; Stanescu, Horia C; Zdebik, Anselm A; Chaganti, R Krishna; Nussbaum, Robert L; Kleta, Robert; Gahl, William A; Boehm, Manfred

    2011-02-03

    Arterial calcifications are associated with increased cardiovascular risk, but the genetic basis of this association is unclear. We performed clinical, radiographic, and genetic studies in three families with symptomatic arterial calcifications. Single-nucleotide-polymorphism analysis, targeted gene sequencing, quantitative polymerase-chain-reaction assays, Western blotting, enzyme measurements, transduction rescue experiments, and in vitro calcification assays were performed. We identified nine persons with calcifications of the lower-extremity arteries and hand and foot joint capsules: all five siblings in one family, three siblings in another, and one patient in a third family. Serum calcium, phosphate, and vitamin D levels were normal. Affected members of Family 1 shared a single 22.4-Mb region of homozygosity on chromosome 6 and had a homozygous nonsense mutation (c.662C→A, p.S221X) in NT5E, encoding CD73, which converts AMP to adenosine. Affected members of Family 2 had a homozygous missense mutation (c.1073G→A, p.C358Y) in NT5E. The proband of Family 3 was a compound heterozygote for c.662C→A and c.1609dupA (p.V537fsX7). All mutations found in the three families result in nonfunctional CD73. Cultured fibroblasts from affected members of Family 1 showed markedly reduced expression of NT5E messenger RNA, CD73 protein, and enzyme activity, as well as increased alkaline phosphatase levels and accumulated calcium phosphate crystals. Genetic rescue experiments normalized the CD73 and alkaline phosphatase activity in patients' cells, and adenosine treatment reduced the levels of alkaline phosphatase and calcification. We identified mutations in NT5E in members of three families with symptomatic arterial and joint calcifications. This gene encodes CD73, which converts AMP to adenosine, supporting a role for this metabolic pathway in inhibiting ectopic tissue calcification. (Funded by the National Human Genome Research Institute and the National Heart, Lung

  8. NT5E Mutations and Arterial Calcifications

    PubMed Central

    St. Hilaire, Cynthia; Ziegler, Shira G.; Markello, Thomas C.; Brusco, Alfredo; Groden, Catherine; Gill, Fred; Carlson-Donohoe, Hannah; Lederman, Robert J.; Chen, Marcus Y.; Yang, Dan; Siegenthaler, Michael P.; Arduino, Carlo; Mancini, Cecilia; Freudenthal, Bernard; Stanescu, Horia C.; Zdebik, Anselm A.; Chaganti, R. Krishna; Nussbaum, Robert L.; Kleta, Robert; Gahl, William A.; Boehm, Manfred

    2011-01-01

    BACKGROUND Arterial calcifications are associated with increased cardiovascular risk, but the genetic basis of this association is unclear. METHODS We performed clinical, radiographic, and genetic studies in three families with symptomatic arterial calcifications. Single-nucleotide-polymorphism analysis, targeted gene sequencing, quantitative polymerase-chain-reaction assays, Western blotting, enzyme measurements, transduction rescue experiments, and in vitro calcification assays were performed. RESULTS We identified nine persons with calcifications of the lower-extremity arteries and hand and foot joint capsules: all five siblings in one family, three siblings in another, and one patient in a third family. Serum calcium, phosphate, and vitamin D levels were normal. Affected members of Family 1 shared a single 22.4-Mb region of homozygosity on chromosome 6 and had a homozygous nonsense mutation (c.662C→A, p.S221X) in NT5E, encoding CD73, which converts AMP to adenosine. Affected members of Family 2 had a homozygous missense mutation (c.1073G→A, p.C358Y) in NT5E. The proband of Family 3 was a compound heterozygote for c.662C→A and c.1609dupA (p.V537fsX7). All mutations found in the three families result in nonfunctional CD73. Cultured fibroblasts from affected members of Family 1 showed markedly reduced expression of NT5E messenger RNA, CD73 protein, and enzyme activity, as well as increased alkaline phosphatase levels and accumulated calcium phosphate crystals. Genetic rescue experiments normalized the CD73 and alkaline phosphatase activity in patients’ cells, and adenosine treatment reduced the levels of alkaline phosphatase and calcification. CONCLUSIONS We identified mutations in NT5E in members of three families with symptomatic arterial and joint calcifications. This gene encodes CD73, which converts AMP to adenosine, supporting a role for this metabolic pathway in inhibiting ectopic tissue calcification. (Funded by the National Human Genome Research

  9. Hierarchical influences on the biophysical properties of natural stream channels

    NASA Astrophysics Data System (ADS)

    Stanfield, L. W.; Kilgour, B.

    2005-05-01

    In this paper we focus on how catchment and proximity effects influence the biophysical properties of streams and these conditions are modified by overall landuse in the catchment and site conditions. Biophysical data (fish, inverts, instream habitat, temperature and baseflow) were collected on wadable streams flowing into the Lake Ontario basin. A GIS application was developed to characterize the landscape conditions for each site. For each of 700 -1400 sites, biophysical and GIS data (drainage area, geology, landuse, slope, stream length, and climatic conditions) were summarized. We explored the relationship between slope and drainage area and two composite indices, one the baseflow index (BFI) combined geology and drainage potential and the other, percent impervious cover (PIC) provided a single metric of disturbance on the landscape. Multivariate approaches were used to develop models to relate each metric to landscape conditions, and PIC. Residuals of this analysis were related to local conditions to determine how much of the remaining variance was explained by these conditions. Our results indicate that several metrics demonstrate a threshold response to PIC and that local conditions have minimal capacity to mitigate these effects. Below the threshold several metrics demonstrated a linear response to PIC that enables predictions to be made of effects from development in a catchment. Instream habitat conditions were more important for some biota (e.g. brown trout) than others. We demonstrate how model results can be used to classify sites or stream segments based on predicted conditions and how results can be used to generate coarse population estimates

  10. Influence of Free Radicals on the Intrinsic MRI Relaxation Properties.

    PubMed

    Tain, Rong-Wen; Scotti, Alessandro M; Li, Weiguo; Zhou, Xiaohong Joe; Cai, Kejia

    2017-01-01

    Free radicals are critical contributors in various conditions including normal aging, Alzheimer's disease, cancer, and diabetes. Currently there is no non-invasive approach to image tissue free radicals based on endogenous contrast due to their extremely short lifetimes and low in vivo concentrations. In this study we aim at characterizing the influence of free radicals on the MRI relaxation properties. Phantoms containing free radicals were created by treating egg white with various H 2 O 2 concentrations and scanned on a 9.4 T MRI scanner at room temperature. T1 and T2 relaxation maps were generated from data acquired with an inversion recovery sequence with varied inversion times and a multi-echo spin echo sequence with varied echo times (TEs), respectively. Results demonstrated that free radicals express a strong shortening effect on T1, which was proportional to the H 2 O 2 concentration, and a relatively small reduction in T2 (<10%). Furthermore, the sensitivity of this approach in the detection of free radicals was estimated to be in the pM range that is within the physiological range of in vivo free radical expression. In conclusion, the free radicals show a strong paramagnetic effect that may be utilized as an endogenous MRI contrast for its non-invasive in vivo imaging.

  11. Influence of chemical treatments on adhesion properties of hemp fibres.

    PubMed

    Le Troëdec, M; Rachini, A; Peyratout, C; Rossignol, S; Max, E; Kaftan, O; Fery, A; Smith, A

    2011-04-01

    In addition to be an environmentally friendly material, hemp fibres are also inexpensive reinforcements in thermoplastics or concrete composites, due to their intrinsic mechanical, thermal and acoustic properties. The morphology of hemp fibres has been chemically modified in order to enhance the matrix/fibre interface and has been examined by Scanning Electron Microscopy (SEM). In this paper, Gas Chromatography (GC) and Atomic Force Microscopy (AFM) were used to investigate the influence of treatments on the composition of hemp fibres and also on the micro-adhesive interactions between a silica colloidal probe and the surface of the fibres using Chemical Force Microscopy (CFM). Microscopy studies and chemical analysis showed that each treatment tends to lead to a morphology of interconnected web-like structure of hemp fibres. It was found that on an average, the adhesion force, contribution of capillary force and Van der Waals' forces, is higher in the case of NaOH treatment. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Triglycidylamine Cross-linking Combined with Ethanol Inhibits Bioprosthetic Heart Valve Calcification

    PubMed Central

    Connolly, Jeanne M.; Bakay, Marina A.; Alferiev, Ivan S.; Gorman, Robert C.; Gorman, Joseph H.; Kruth, Howard S.; Ashworth, Paul E.; Kutty, Jaishankar K.; Schoen, Frederick J.; Bianco, Richard W.; Levy, Robert J.

    2012-01-01

    Background One of the most important factors responsible for the calcific failure of bioprosthetic heart valves is glutaraldehyde cross-linking. Ethanol (EtOH) incubation after glutaraldehyde cross-linking has previously been reported to confer anti-calcification efficacy for bioprostheses. The present studies investigated the anticalcification efficacy in vivo of the novel cross-linking agent, triglycidyl amine (TGA), with or without EtOH incubation, in comparison to glutaraldehyde. Methods TGA cross-linking (+/− EtOH) was used to prepare porcine aortic valves for both rat subdermal implants and sheep mitral valve replacements, for comparisons with glutaraldehyde-fixed controls. Thermal denaturation temperature (Ts), an index of cross-linking, cholesterol extraction, and hydrodynamic properties were quantified. Explant endpoints included quantitative and morphologic assessment of calcification. Results Ts after TGA were intermediate between unfixed and glutaraldehyde-fixed. EtOH incubation resulted in almost complete extraction of cholesterol from TGA or glutaraldehyde-fixed cusps. Rat subdermal explants (90days) demonstrated that TGA-EtOH resulted in a significantly greater level of inhibition of calcification than other conditions. Thus, TGA-ethanol stent mounted porcine aortic valve bioprostheses were fabricated for comparisons with glutaraldehyde-pretreated controls. In hydrodynamic studies, TGA-EtOH bioprostheses had lower pressure gradients than glutaraldehyde-fixed. TGA-ethanol bioprostheses used as mitral valve replacements in juvenile sheep (150 days) demonstrated significantly lower calcium levels in both explanted porcine aortic cusp and aortic wall samples compared to glutaraldehyde-fixed controls. However, TGA-EtOH sheep explants also demonstrated isolated calcific nodules and intracuspal hematomas. Conclusions TGA-EtOH pretreatment of porcine aortic valves confers significant calcification resistance in both rat subdermal and sheep circulatory

  13. Preexisting venous calcification prior to dialysis vascular access surgery.

    PubMed

    Lee, Timmy; Safdar, Nida; Mistry, Meenakshi J; Wang, Yang; Chauhan, Vibha; Campos, Begoña; Munda, Rino; Cornea, Virgilius; Roy-Chaudhury, Prabir

    2012-01-01

    Vascular calcification is present in arterial vessels used for dialysis vascular access creation prior to surgical creation. Calcification in the veins used to create a new vascular access has not previously been documented. The objective of this study was to describe the prevalence of venous calcification in samples collected at the time of vascular access creation. Sixty-seven vein samples were studied. A von Kossa stain was performed to quantify calcification. A semi-quantitative scoring system from 0 to 4+ was used to quantify the percentage positive area for calcification as a fraction of total area (0: 0; 1+: 1-10%; 2+: 11-25%; 3+: 26-50%; 4+: >50% positive). Twenty-two of 67 (33%) samples showed evidence of venous calcification. Histologic examination showed varying degrees of calcification within each cell layer. Among the subset of patients with calcification, 4/22 (18%), 19/22 (86%), 22/22 (100%), and 7/22 (32%) had calcification present within the endothelium, intima, media, and adventitia, respectively. The mean semi-quantitative scores of the 22 samples with calcification were 0.18 ± 0.08, 1.2 ± 0.14, 1.6 ± 0.13, and 0.36 ± 0.12 for the endothelium, intima, media, and adventitia, respectively. Our results demonstrate that vascular calcification is present within veins used to create new dialysis vascular access, and located predominately within the neointimal and medial layers. © 2012 Wiley Periodicals, Inc.

  14. Vascular calcification in Mexican hemodialysis patients.

    PubMed

    Rojas-Campos, Enrique; Herrera-Llamas, Rebeca; Montañez-Fernández, José L; Martínez-Martínez, Petra; Andrade-Sierra, Jorge; Avila-Baray, Angel A; Cueto-Manzano, Alfonso M

    2013-11-01

    Vascular calcification (VC) is a predictor of poor survival and cardiovascular outcome in end-stage renal disease (ESRD) patients; however, there is scarce information of VC in Latin America, and virtually no data in our setting. We undertook this study to evaluate the prevalence and characteristics of VC in a hemodialysis (HD) population from western Mexico and to determine possible associated factors. This was a cross-sectional study performed in 52 patients. VC was evaluated using plain X-ray films (Adragao's score) of hands and pelvis; clinical and biochemical variables were also collected. Statistical analysis was carried out with Student t and χ(2) tests performed as appropriate and logistic regression to determine predictors of VC. Mean age was 43 years, 48% were female, 23% had diabetes mellitus (DM), and median time on dialysis was 46 months. Percentage prevalence was 52% with a mean calcification score of 2.0 ± 2.6; 23% of patients had severe calcification. VC was present in about 23-37% among the different vascular territories evaluated (radial, digital, femoral and iliac). Patients with calcification were significantly older, had a higher frequency of DM, higher alkaline phosphatase and lower HDL lipoproteins than those without VC. In the multivariate analysis, VC in these patients was significantly predicted only by an older age (OR [95% CI]: 1.15 [1.01-1.31], p = 0.04); lower HDL-cholesterol and higher alkaline phosphatase were marginal predictors. Half of our HD patients had VC. Territories of radial, iliac, femoral and digital arteries were roughly equally affected, and 25% of patients had a calcification considered as severe. Older age was the only significant predicting variable for VC, with low HDL-cholesterol and high alkaline phosphatase as marginal predictors. Copyright © 2013 IMSS. Published by Elsevier Inc. All rights reserved.

  15. Intracranial physiological calcifications evaluated with cone beam CT.

    PubMed

    Sedghizadeh, P P; Nguyen, M; Enciso, R

    2012-12-01

    The purpose of this study was to evaluate cone beam CT (CBCT) scans for the presence of physiological and pathological intracranial calcifications. CBCT scans from male and female patients that met our ascertainment criteria were evaluated retrospectively (n=500) for the presence of either physiological or pathological intracranial calcifications. Out of the 500 patients evaluated, 176 had evidence of intracranial physiological calcification (35.2% prevalence), and none had evidence of pathological calcification. There was a 3:2 male-to-female ratio and no ethnic predilection; the ages of affected patients ranged from 13 years to 82 years with a mean age of 52 years. The majority of calcifications appeared in the pineal/habenular region (80%), with some also appearing in the choroid plexus region bilaterally (12%), and a smaller subset appearing in the petroclinoid ligament region bilaterally (8%). Intracranial physiological calcifications can be a common finding on CBCT scans, whereas pathological intracranial calcifications are rare.

  16. Metal and calcification artifact reduction for digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Wicklein, Julia; Jerebko, Anna; Ritschl, Ludwig; Mertelmeier, Thomas

    2017-03-01

    Tomosynthesis images of the breast suffer from artifacts caused by the presence of highly absorbing materials. These can be either induced by metal objects like needles or clips inserted during biopsy devices, or larger calcifications inside the examined breast. Mainly two different kinds of artifacts appear after the filtered backprojection procedure. The first type is undershooting artifacts near edges of high-contrast objects caused by the filtering step. The second type is out-of-plane (ripple) artifacts that appear even in slices where the metal object or macrocalcifications does not exist. Due to the limited angular range of tomosynthesis systems, overlapping structures have high influence on neighboring regions. To overcome these problems, a segmentation of artifact introducing objects is performed on the projection images. Both projection versions, with and without high-contrast objects are filtered independently to avoid undershootings. During backprojection a decision is made for each reconstructed voxel, if it is artifact or high-contrast object. This is based on a mask image, gained from the segmentation of high-contrast objects. This procedure avoids undershooting artifacts and additionally reduces out-of-plane ripple. Results are demonstrated for different kinds of artifact inducing objects and calcifications.

  17. New treatments using alginate in order to reduce the calcification of bovine bioprosthetic heart valve tissue.

    PubMed

    Shanthi, C; Rao, K P

    1997-01-01

    Calcification limits the functional lifetime of cardiac valve substitutes fabricated from glutaraldehyde preserved bovine pericardium. Host factors, mainly younger age, and implant factors, mainly glutaraldehyde cross-linking, are implicated in the calcification process. Glutaraldehyde cross-linking is believed to activate the potential sites in the tissues for biocalcification. In the present work, we investigated the possibility of using alginate azide (AA) instead of glutaraldehyde for the preservation of pericardial tissues in order to enhance the durability of bioprosthetic heart valves. Grafting with poly(GMA-BA) copolymer to the alginate azide cross-linked pericardial (AACPC) tissue was carried out to obtain better stability, strength, and anticalcification properties. The strength property and thermal stability of the AA cross-linked tissues were studied. Calcification studies in rat subdermal models reveal that AA cross-linking reduces the calcification to negligible levels. After 30 days implantation, the calcium content was found to be 10.4 +/- 1.2 and 6.1 +/- 0.3 micrograms mg-1 for untreated AACPC and polymer grafted AACPC, respectively, compared to a value of 100 +/- 1.2 micrograms mg-1 calcium recorded for control glutaraldehyde cross-linked pericardial (GCPC) tissues.

  18. 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

  19. Does pH influence soil hydro-mechanical properties?

    NASA Astrophysics Data System (ADS)

    Chaplain, V.; Défossez, P.; Delarue, G.; Dexter, A. R.; Richard, G.; Tessier, D.

    2009-04-01

    Does pH influence soil hydro-mechanical properties ? V. Chaplain1, P. Défossez2, G. Delarue1, A.R. Dexter3, G. Richard3 and D. Tessier1. 1 UR INRA PESSAC RD 10, F-78026 Versailles cedex 2 UMR INRA/URCA FARE, 2 Esplanade Roland Garros, BP 224 F-51686 Reims cedex 2 3 UR INRA Sols 2163 Avenue de la Pomme de Pin - CS 40001 ARDON F-45075 Orléans Cedex 2 Corresponding author : chaplain@versailles.inra.fr Structure of soils and its dynamic, physico-chemistry of the interface are of a great importance in the fate of organic pollutants because it governs the accessibility of pollutants to micro-organisms. The soil structure of soils is related to physical parameters (texture, density, water content) but the physico-chemical properties of the interface is not considered. In this study we performed hydro-mechanical measurements on soil samples taken from the 42-plot long-term experiment in Versailles. Indeed six plots were selected to cover a large range of pH values from acid (3.5) to alkaline (8.2) due to the repeated application of fertilizers. Soils were taken in the 0-20 cm and in the 30-35 cm layer out of the ploughed zone. All soils had similar texture and composition with low organic carbon. Therefore pH changes the surface charges and hydrophobicity that are implied in aggregation process. The two layers had the same pH values. The precompression stress Pc and the compression index Cc were derived from confined compression tests performed on remoulded soil samples (density 1.45 g/cm3) at saturation. Results shows that the precompression stress increased at pH lower than 4. In acid case, precompression stress was higher in subsoil. This increase of Pc was attributed to the hydrophobicity due in part to the condensation of charges probably sensitive to the humectation/dessication processes.

  20. Physiologic calcification of the pineal gland in children on computed tomography: prevalence, observer reliability and association with choroid plexus calcification.

    PubMed

    Doyle, Anthony James; Anderson, Graeme D

    2006-07-01

    To evaluate the prevalence of physiologic pineal calcification, estimate observer variability, and examine the association with choroid plexus calcification. A retrospective review of hard copy head computed tomography films of 242 patients age younger than 16 years by two independent observers. Physiologic pineal calcification was present in 20% of the whole group, in 39% of those 8-14 years age, in 8% of those younger than 10 years age, and in 1% of those younger than age 6 years. Observer agreement was very good (kappa = 0.72). Choroid plexus calcification was present in 16% and was four times as common in those with pineal calcification (38% versus 10%, P = .005), with very good observer agreement (kappa = 0.74). Physiologic pineal calcification is more common in children than previously reported, mostly because of improving computed tomography technology. There is an association with choroid plexus calcification.

  1. Calcification by reef-building sclerobionts.

    PubMed

    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

  2. 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

  3. COX2 Inhibition Reduces Aortic Valve Calcification In Vivo

    PubMed Central

    Wirrig, Elaine E.; Gomez, M. Victoria; Hinton, Robert B.; Yutzey, Katherine E.

    2016-01-01

    Objective Calcific aortic valve disease (CAVD) is a significant cause of morbidity and mortality, which affects approximately 1% of the US population and is characterized by calcific nodule formation and stenosis of the valve. Klotho-deficient mice were used to study the molecular mechanisms of CAVD as they develop robust aortic valve (AoV) calcification. Through microarray analysis of AoV tissues from klotho-deficient and wild type mice, increased expression of the gene encoding cyclooxygenase 2/COX2 (Ptgs2) was found. COX2 activity contributes to bone differentiation and homeostasis, thus the contribution of COX2 activity to AoV calcification was assessed. Approach and Results In klotho-deficient mice, COX2 expression is increased throughout regions of valve calcification and is induced in the valvular interstitial cells (VICs) prior to calcification formation. Similarly, COX2 expression is increased in human diseased AoVs. Treatment of cultured porcine aortic VICs with osteogenic media induces bone marker gene expression and calcification in vitro, which is blocked by inhibition of COX2 activity. In vivo, genetic loss of function of COX2 cyclooxygenase activity partially rescues AoV calcification in klotho-deficient mice. Moreover, pharmacologic inhibition of COX2 activity in klotho-deficient mice via celecoxib-containing diet reduces AoV calcification and blocks osteogenic gene expression. Conclusions COX2 expression is upregulated in CAVD and its activity contributes to osteogenic gene induction and valve calcification in vitro and in vivo. PMID:25722432

  4. Intracellular precipitation of hydroxyapatite mineral and implications for pathologic calcification.

    PubMed

    Azari, Fereshteh; Vali, Hojatollah; Guerquin-Kern, Jean-Luc; Wu, Ting-Di; Croisy, Alain; Sears, S Kelly; Tabrizian, Maryam; McKee, Marc D

    2008-06-01

    In contrast to physiologic biomineralization occurring in bones, teeth and otoconia in vertebrates, calcification of soft tissues occurs in many pathologic conditions. Although similarities have been noted between the two processes, and despite the important clinical consequences of ectopic calcification, the molecular mechanisms regulating ectopic calcification are poorly understood. Although calcification is mainly extracellular, intracellular calcification has been reported and might indeed contribute to pathologic calcification of soft tissues. To better understand the process of intracellular calcification as a potential origin for pathologic calcification, and to examine the role of proteoglycans in this process, we investigated a pattern of intracellular nucleation and growth of hydroxyapatite in Madin-Darby Canine Kidney (MDCK) epithelial cells using electron microscopy, secondary ion mass spectroscopy (NanoSIMS), cytochemical staining, immunolabeling and biochemical analysis. We report here that under mineralizing cell culture conditions where beta-glycerophosphate (betaGP) was added as an exogenous organic source of phosphate, betaGP-cleaving alkaline phosphatase activity increased and hydroxyapatite crystals subsequently nucleated within intracellular, membrane-bounded compartments. The small, leucine-rich proteoglycan decorin was also upregulated and associated with mineral in these cultures. Such information provides insight into the mechanisms leading to pathologic calcification and describes a process whereby hydroxyapatite deposition in cells might lead to ectopic calcification.

  5. Hydrogen sulfide attenuates calcification of vascular smooth muscle cells via KEAP1/NRF2/NQO1 activation.

    PubMed

    Aghagolzadeh, Parisa; Radpour, Ramin; Bachtler, Matthias; van Goor, Harry; Smith, Edward R; Lister, Adam; Odermatt, Alex; Feelisch, Martin; Pasch, Andreas

    2017-10-01

    Vascular calcification is a common health problem related to oxidative stress, inflammation, and circulating calciprotein particles (CPP). Hydrogen sulfide is an endogenous signaling molecule with antioxidant properties and potential for drug development targeting redox signaling. Yet, its molecular mechanisms of action in vascular smooth muscle cell (VSMC) calcification have not been delineated. We therefore sought to identify key pathways involved in the calcification-inhibitory properties of sulfide employing our recently developed CPP-induced VSMC calcification model. Using next-generation sequencing, we investigated the transcriptomic changes of sodium hydrosulfide-treated versus non-treated calcifying VSMCs. The potential role of candidate genes and/or regulatory pathways in prevention of calcification was investigated by small interfering RNA (siRNA). CPP led to a pronounced accumulation of cell-associated calcium, which was decreased by sulfide in a concentration-dependent manner. Both, CPP-induced hydrogen peroxide production and enhanced pro-inflammatory/oxidative stress-related gene expression signatures were attenuated by sulfide-treatment. Gene ontology enrichment and in silico pathway analysis of our transcriptome data suggested NAD(P)H dehydrogenase [quinone] 1 (NQO1) as potential mediator. Corroborating these findings, silencing of Kelch-like ECH-associated protein 1 (KEAP1), an inhibitor of nuclear factor (erythroid-derived 2)-like 2 (NRF2) nuclear activity, enhanced NQO1 expression, whereas NRF2 silencing reduced the expression of NQO1 and abrogated the calcification-suppressing activity of sulfide. Moreover, immunofluorescence microscopy and Western blot analysis confirmed nuclear translocation of NRF2 by sulfide in VSMC. Sulfide attenuates CPP-induced VSMC calcification in vitro via the KEAP1-NRF2 redox sensing/stress response system by enhancing NQO1 expression. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Comparing different calcification scores to detect outcomes in chronic kidney disease patients with vascular calcification.

    PubMed

    NasrAllah, Mohamed M; Nassef, Amr; Elshaboni, Tarik H; Morise, Fadia; Osman, Noha A; Sharaf El Din, Usama A

    2016-10-01

    There is no consensus on the most appropriate technique to diagnose vascular calcification in chronic kidney disease. This is primarily because of the absence of direct comparisons of predictive values of the various calcification scores, especially outside the coronary vascular beds, to detect clinical outcomes. We included 93 haemodialysis patients and performed 6 vascular calcification scores: two scores utilised simple X-rays of abdominal aorta and peripheral vessels. CT scans of the thoracic, upper abdominal and lower abdominal aorta were performed to calculate the aortic calcification index and CT of the pelvis for calcification of iliac vessels. Patients were followed for 63months (mean 46.8months) for first major cardiovascular events and mortality. Nineteen cardiovascular events and 28 deaths occurred. Calcification was detected more sensitively in central and peripheral beds using CT scans compared to X-rays (p<0.001). CT scans detected calcification more frequently in distal than proximal vascular beds (p<0.001). Calcification of the pelvic vessels and lower abdominal aorta were most predictive of events including pre-existing cardiovascular disease O.R. 6.5 (95% C.I. 2-22; p=0.001) and O.R. 3 (95% C.I. 1.1-9; p=0.035); new major cardiovascular events H.R. 4.2 (95% C.I. 1.5-11; p=0.006) and H.R. 2 (95% C.I. 0.8-5.3; p=0.1) as well as mortality H.R. 2.8 (95% C.I. 1.3-6; p=0.01) and H.R. 2.2 (95% C.I. 1.04-5; p=0.04) respectively. CT based techniques are more sensitive than plain X-rays at detecting peripheral and aortic vascular calcifications. Distal CT scans of the aorta and pelvic vessels have the highest predictive value for cardiovascular events and mortality. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. 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

  8. Vascular calcification and osteolysis in diabetic neuropathy-is RANK-L the missing link?

    PubMed

    Jeffcoate, W

    2004-09-01

    Diabetic neuropathy is associated with osteopenia and calcification of vascular smooth muscle cells. These changes are most marked in patients with acute neuropathic osteoarthropathy (Charcot foot), in which osteopenia is universal and the prevalence of vascular calcification exceeds 90%. While it has been thought that both osteopenia and vascular calcification may be linked to sympathetic denervation with increased peripheral limb perfusion, the cellular mechanism was not clear. However, the recent recognition that the receptor activator of nuclear factor kappa B ligand (RANK-L)/osteoprotegerin (OPG) signalling pathway is central to the processes regulating bone turnover in a wide variety of medical conditions has raised the possibility that the same cytokines may be involved in the osteolysis which accompanies diabetic neuropathy. This is made more likely by the realisation that the RANK-L/OPG pathway is also thought to mediate the calcification of vascular smooth muscle cells in coronary and peripheral vascular disease. The circumstantial evidence underpinning this hypothesis is reviewed here, and it is suggested that the unregulated activation of RANK-L-mediated effects on bone and arteries may be triggered by the loss of nerve-derived peptides, e.g. calcitonin gene-related peptide, which normally exert a moderating influence on the pathway.

  9. Kangaroo versus porcine aortic valve tissue--valve geometry morphology, tensile strength and calcification potential.

    PubMed

    Neethling, W M; Papadimitriou, J M; Swarts, E; Hodge, A J

    2000-06-01

    Valve related factors and patient related factors are responsible for calcification of valvular bioprostheses. Recent studies showed different donor and recipient species have different influences on the total calcification rate of bioprostheses. This study was performed to evaluate and compare Kangaroo aortic valve leaflets with porcine aortic valve leaflets. Experimental design. Prospective study. Setting. Cardio-thoracic experimental research of a university department. Glutaraldehyde-fixed Kangaroo and porcine valve leaflets were evaluated in vitro according to valve geometry (internal diameter and leaflet thickness), morphology (light and electron microscopy) and tensile strength. In vivo evaluation consisted of implantation in a rat model for 8 weeks, Von Kossa stain for calcium and atomic absorption spectrophotometry for total extractable calcium content. Kangaroo valves indicated a smaller internal valve diameter as well as a thinner valve leaflet (p<0.01, ANOVA) at corresponding body weight, less proteoglycan spicules in the fibrosa, increased elasticity (p<0.05) and low calcification potential (p<0.01, confidence interval 95%). Kangaroo aortic valve leaflets have different valvular qualities compared to porcine valve tissue. Kangaroo valve leaflets are significantly superior to porcine valve leaflets as far as calcification is concerned. These results are encouraging and suggest further in vivo evaluation in a larger animal model before clinical application can be considered.

  10. Seasonality in calcification response of Hawaiian reef coral, Montipora capitata, under climate change projections

    NASA Astrophysics Data System (ADS)

    Bahr, K.; Rodgers, K.; Jokiel, P. L.

    2016-02-01

    The response of coral reef communities to future environmental conditions is a topic of enormous concern and considerable debate. However, information is lacking concerning the interaction between local and global stressors on modern reefs. Irradiance and temperature, along with other numerous environmental factors that regulate coral calcification rates and productivity, are predicted to change with future elevated carbon dioxide (CO2) emissions. Therefore, an experiment was performed in continuous flow mesocosms under full solar radiation to describe the direct and interactive effects of temperature, irradiance, and pCO2 on the calcification of the Hawaiian reef building coral, Montipora capitata across seasonal and temporal scales. Corals were subjected to twelve experimental treatments composed of two pCO2 levels (present day levels, 2X present), two temperature regimes (ambient, heated +2°C), and three conditions of irradiance (ambient, 50% and 90% reduction). Results revealed irradiance and temperature stress have the strongest influence on coral calcification with pCO2 playing a lesser role. The effects of pCO2 also varied among temperature and irradiance regimes. Large decreases in calcification were observed in corals under ambient irradiance levels that were exposed to elevated temperatures and high pCO2 levels. These results suggest the interaction of these environmental parameters may alter optimal growth conditions of M. capitata under future climate change projections.

  11. Vascular Calcification and Stone Disease: A New Look towards the Mechanism.

    PubMed

    Yiu, Allen J; Callaghan, Daniel; Sultana, Razia; Bandyopadhyay, Bidhan C

    Calcium phosphate (CaP) crystals are formed in pathological calcification as well as during stone formation. Although there are several theories as to how these crystals can develop through the combined interactions of biochemical and biophysical factors, the exact mechanism of such mineralization is largely unknown. Based on the published scientific literature, we found that common factors can link the initial stages of stone formation and calcification in anatomically distal tissues and organs. For example, changes to the spatiotemporal conditions of the fluid flow in tubular structures may provide initial condition(s) for CaP crystal generation needed for stone formation. Additionally, recent evidence has provided a meaningful association between the active participation of proteins and transcription factors found in the bone forming (ossification) mechanism that are also involved in the early stages of kidney stone formation and arterial calcification. Our review will focus on three topics of discussion (physiological influences-calcium and phosphate concentration-and similarities to ossification, or bone formation) that may elucidate some commonality in the mechanisms of stone formation and calcification, and pave the way towards opening new avenues for further research.

  12. Zinc deprivation inhibits extracellular matrix calcification through decreased synthesis of matrix proteins in osteoblasts.

    PubMed

    Alcantara, Ethel H; Lomeda, Ria-Ann R; Feldmann, Joerg; Nixon, Graeme F; Beattie, John H; Kwun, In-Sook

    2011-10-01

    Zinc is implicated as an activator for bone formation, however, its influence on bone calcification has not been reported. This study examined how zinc regulates the bone matrix calcification in osteoblasts. Two osteoblastic MC3T3-E1 cell subclones (SC 4 and SC 24 as high and low osteogenic differentiation, respectively) were cultured in normal osteogenic (OSM), Zinc deficient (Zn-, 1 μM), or adequate (Zn+, 15 μM) media up to 20 days. Cells (SC 4) were also supplemented with (50 μg/mL) or no ascorbic acid (AA) in combination with Zinc treatment. Zn- decreased collagen synthesis and matrix accumulation. Although AA is essential for collagen formation, its supplementation could not compensate for Zinc deficiency-induced detrimental effects on extracellular matrix mineralization. Zn- also decreased the medium and cell layer alkaline phosphatase ALP activity. This decreased ALP activity might cause the decrease of Pi accumulation in response to Zn-, as measured by von Kossa staining. Ca deposition in cell layers, measured by Alizarin red S staining, was also decreased by Zn(-) . Our findings suggest that zinc deprivation inhibits extracellular matrix calcification in osteoblasts by decreasing the synthesis and activity of matrix proteins, type I collagen and ALP, and decreasing Ca and Pi accumulation. Therefore zinc deficiency can be considered as risk factor for poor extracellular matrix calcification. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Hereditary folate malabsorption with extensive intracranial calcification.

    PubMed

    Ahmad, Ikhlas; Mukhtar, Gousia; Iqbal, Javed; Ali, Syed Wajid

    2015-01-01

    Anemia is a common accompaniment of cerebral palsy, mental retardation and neurodegenerative disorders. A 4-year-old boy with chronic megaloblastic anemia, global developmental delay, seizures, intracranial calcification and new onset neuro-regression. A diagnosis of hereditary folate malabsorption was made, and he was put on oral and injectable folinic acid. Marked improvement at 6 month follow up. Hereditary folate malabsorption should be suspected in any child having megaloblastic anemia and neuro degeneration disorder.

  14. Motion trajectories and object properties influence perceived direction of motion.

    PubMed

    Magnussen, Camilla M; Orbach, Harry S; Loffler, Gunter

    2013-10-18

    Judging the motion of objects is a fundamental task that the visual system executes in everyday life in order for us to navigate and interact safely with our surroundings. A number of strategies have been suggested to explain how the visual system uses motion information from different points of an object to compute veridical directions of motion. These include combining ambiguous signals from object contours via a vector summation (VS) or intersection of constraints (IOC) calculation, pooling information using a maximum likelihood or tracking object features. We measured the perceived direction of motion for a range of cross-shaped stimuli (composed of two superimposed lines) to test how accurately humans perceive their motion and compared data to predictions from these strategies. Crosses of different shapes (defined by the angle between the component lines) translated along 16 directions of motion with constant speed. The crosses either moved along one of their symmetry axes (balanced conditions with line components equidistant to the direction of motion) or had their symmetry axis tilted relative to the motion (unbalanced conditions) Data show reproducible differences between observers, including occasional bimodal behaviour, and exhibit the following common patterns. There is a general dependence on direction of motion: For all conditions, when motion is along cardinal axes (horizontal and vertical), perception is largely veridical. For non-cardinal directions, biases are typically small (<10 deg) when crosses are balanced but large biases occur (≥30 deg) when crosses are tilted relative to their direction of motion. Factors influencing the pattern of biases are the shape and tilt of the cross as well as the proximity of its direction of motion to cardinal axes. The dependence of the biases on the direction of motion is inconsistent with any isotropic mechanisms including VS, IOC, maximum likelihood or feature tracking. Instead, perception is biased by a

  15. Retropharyngeal calcific tendonitis: report of two cases.

    PubMed

    Razon, Rhea Victoria B; Nasir, Asad; Wu, George S; Soliman, Manal; Trilling, Jeffrey

    2009-01-01

    Retropharyngeal calcific tendonitis is an inflammatory process of the superior oblique tendons of the longus colli muscle, a neck flexor in the upper cervical spine, caused by deposition of calcium hydroxyapatite crystals; the definitive diagnostic test is computed tomography (CT). Presented in this article are two cases seen at our institution. Patients typically present with acute onset of neck pain/spasm, odynophagia, dysphagia, and/or low grade fevers. Leukocytosis and elevated erythrocyte sedimentation rate may be noted. It is important to understand this entity because its signs and symptoms are mimickers of those of the more serious condition of retropharyngeal space abscess. Calcific tendonitis is managed conservatively whereas retropharyngeal abscess requires incision and drainage. Some may argue that this entity is a zebra because its reported incidence in the literature is low. However, most of these studies were done in an era when CT was not yet in vogue. With today's widespread use of CT and its superb ability to visualize the calcification, the true incidence of this condition is probably higher and, thus, it is important for the family practitioner to be aware of this entity. The astute clinician may save the patient from unnecessary diagnostic workup, undue anxiety, and delays in hospital discharge.

  16. Mammographically Detectable Breast Arterial Calcification and Atherosclerosis

    PubMed Central

    Shah, Neeraj; Chainani, Vinod; Delafontaine, Patrice; Abdo, Abir; Lafferty, James; Rafeh, Nidal Abi

    2014-01-01

    Breast arterial calcification (BAC), observed as an incidental finding on screening mammograms, represents degenerative calcific changes occurring in the mammary arteries, with increasing age. The aim of this review is to discuss relevant literature examining relation between BAC and atherosclerosis. After a thorough literature search, in OVID and PubMed, 199 studies were identified, of which 25 were relevant to our review. Data were abstracted from each study and statistical analysis was done, including calculation of odds ratios and construction of forest plots. A total of 35,542 patients were enrolled across 25 studies looking at an association between BAC and coronary artery disease, cardiovascular disease, stroke, cerebral artery disease, carotid and peripheral artery diseases, and coronary artery calcification. A majority of the studies showed a statistically significant relation between BAC and presence of coronary artery disease cardiovascular disease and associated mortality. Sensitivity of BAC in predicting cardiovascular events was low, but specificity was high. BAC was predictive of incident and prevalent stroke but not mortality of stroke. Similarly, BAC was predictive of cerebral, carotid, and peripheral artery diseases. The role of BAC as a surrogate marker of coronary and systemic atherosclerosis is currently uncertain. Its role may be further elucidated by more large-scale prospective studies and clinical experience. PMID:23584424

  17. Calcium intake, vascular calcification, and vascular disease.

    PubMed

    Spence, Lisa A; Weaver, Connie M

    2013-01-01

    Recent research has reported a possible link between calcium supplementation and increased risk of cardiovascular disease and its endpoints in healthy, older adults. To evaluate the current evidence regarding the impact of calcium supplementation on cardiovascular disease risk and to address research gaps, the present review was conducted. Systematic reviews and meta-analyses were included, when available, along with original articles. The articles included in the review were obtained from PubMed using the following search terms: calcium intake, calcium supplementation, cardiovascular disease, myocardial infarction, mortality, and vascular calcification. The majority of the studies reviewed demonstrated no statistically significant adverse or beneficial effect of calcium supplementation on cardiovascular disease or its endpoints. While some studies indicate a possible increased risk, there is a lack of consensus on these findings and a need exists to further elucidate a mechanism. More experimental data are necessary to understand the impact of calcium intake, both levels and sources, on vascular calcification and vascular disease. The use of (41)C kinetic modeling in the Ossabaw swine provides an approach for assessing soft tissue calcification in an atherosclerotic and normal state to address research gaps.

  18. Aortic Stenosis and Vascular Calcifications in Alkaptonuria

    PubMed Central

    Hannoush, Hwaida; Introne, Wendy J.; Chen, Marcus Y.; Lee, Sook-Jin; O'Brien, Kevin; Suwannarat, Pim; Kayser, Michael A.; Gahl, William A.; Sachdev, Vandana

    2011-01-01

    Alkaptonuria is a rare metabolic disorder of tyrosine catabolism in which homogentisic acid (HGA) accumulates and is deposited throughout the spine, large joints, cardiovascular system, and various tissues throughout the body. In the cardiovascular system, pigment deposition has been described in the heart valves, endocardium, pericardium, aortic intima and coronary arteries. The prevalence of cardiovascular disease in patients with alkaptonuria varies in previous reports . We present a series of 76 consecutive adult patients with alkaptonuria who underwent transthoracic echocardiography between 2000 and 2009. A subgroup of 40 patients enrolled in a treatment study underwent non-contrast CT scans and these were assessed for vascular calcifications. Six of the 76 patients had aortic valve replacement. In the remaining 70 patients, 12 patients had aortic sclerosis and 7 patients had aortic stenosis. Unlike degenerative aortic valve disease, we found no correlation with standard cardiac risk factors. There was a modest association between the severity of aortic valve disease and joint involvement, however, we saw no correlation with urine HGA levels. Vascular calcifications were seen in the coronaries, cardiac valves, aortic root, descending aorta and iliac arteries. These findings suggest an important role for echocardiographic screening of alkaptonuria patients to detect valvular heart disease and cardiac CT to detect coronary artery calcifications. PMID:22100375

  19. Chronic calcific pancreatitis and pancreatic cancer.

    PubMed

    Billah, M M; Chowdhury, M M; Das, B C; Shampa, N N; Khan, Z R

    2014-07-01

    An observational cross-sectional study of 50 cases of chronic calcific pancreatitis patients was conducted in Bangabandhu Sheikh Mujib Medical University (BSMMU) and some other tertiary level hospitals of Dhaka city from August 2008 to July 2010. Patients required laparotomy for different modalities of surgical treatment to manage chronic calcific pancreatitis were included in the study. Biopsy was taken from panceatic duct containing stone during laparotomy to determine the histopathological changes. Among 50 cases female predominance was observed. Male, female ratio was 2:3. Majority (62%) patients were in 20 to 40 years age group. Female presented earlier than male (20-30 years and 30-40 years respectively). All patients complained recurrent attack of epigastric pain. Other presentations were diabetes (74%), malnutrition and weight loss (56%), steatorrhoea (24%) and jaundice (12%). Adenocarcinoma was found in 3(6%) patients (2 male and 1 female) and rests were chronic pancreatitis. Several studies showed the association between chronic calcific pancreatitis and pancreatic cancer. Further large scale study is required to find out the national incidence level.

  20. A Case of Chronic Calcific Nonalcoholic Pancreatitis

    PubMed Central

    Kangas-Dick, Aaron; Khan, Umair; Awoniyi, Oluwafunbi; Waqar, Shanza; Tun, Nu Nwe; Wong, Cynthia

    2016-01-01

    Tropical Calcific Pancreatitis (TCP) is a type of chronic calcific nonalcoholic pancreatitis. Similar to nonalcoholic chronic pancreatitis, it presents in the second and third decades of life; however this type is reported mostly in the developing tropical and subtropical countries. It is associated with the formation of pancreatic calculi and a high probability of developing insulin-dependent diabetes mellitus. Epidemiologic studies have shown that these patients have an increased risk of developing pancreatic carcinoma. The etiology of TCP remains uncertain, with the current consensus suggesting genetics as well as possible toxicity from consuming large amounts of cassava, a tuber. Definite diagnosis of TCP requires younger age of onset, history of malnutrition, and presence of diabetes mellitus along with extensive pancreatic calcification and ductal calculi. When patients meet most but not all of these conditions the term Idiopathic Chronic Pancreatitis (ICP) is used. This is a case of a 44-year-old man who presented with most features seen in TCP, and however, was diagnosed with ICP. PMID:27957355

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Characteristics of calcification in tumors of the pineal gland.

    PubMed

    Lin, S R; Crane, M D; Lin, Z S; Bilaniuk, L; Plassche, W M; Marshall, L; Spataro, R F

    1978-03-01

    Thirty-two cases of proved pineal tumor were analyzed. Calcification was seen in 75%. The size, character, and position of the calcification were useful indicators of abnormality on plain-film evaluation. Fray's cranioangle method was more sensitive than Oon's method in determining abnormal position of the calcified pineal tumor on the lateral skull film. Most calcifications were displaced postero-inferiorly or inferiorly, which can be explained by obstructive hydrocephalus or direct tumor expansion.

  6. Calcifications of the palatine tonsillary region: CT demonstration.

    PubMed

    Aspestrand, F; Kolbenstvedt, A

    1987-11-01

    The scans of 100 consecutive patients referred for computed tomographic examinations that included the oropharynx were reviewed with regard to calcifications of the palatine tonsillary region. Calcifications were found in 20% of the female patients and 13% of the male patients. Ten patients had one calculus, and six had two or more. The sizes of the calculi ranged from 1 to 7 mm. Tonsillary calculi must be included among the diagnostic possibilities when survey radiographs of the neck show soft-tissue calcifications.

  7. Calcification of thoracic aorta – solar eclipse sign

    PubMed Central

    Dhoble, Abhijeet; Puttarajappa, Chethan

    2008-01-01

    Background Calcification of thoracic aorta is very common in old people, especially ones with hypertension. This can sometime be visible on plain chest radiograph. Case Presentation We present a case of a male patient who had extensive deposition of calcium in the thoracic aorta. Conclusion The relationship between aortic calcification and coronary atherosclerosis remains contentious. Computed tomography of the thorax can display this calcification which appears like 'solar eclipse'. PMID:18759981

  8. The matrix metalloproteinases 2 and 9 initiate uraemic vascular calcifications.

    PubMed

    Hecht, Eva; Freise, Christian; Websky, Karoline V; Nasser, Hamoud; Kretzschmar, Nadja; Stawowy, Philipp; Hocher, Berthold; Querfeld, Uwe

    2016-05-01

    The matrix metalloproteinases (MMP) MMP-2 and MMP-9 are physiological regulators of vascular remodelling. Their dysregulation could contribute to vascular calcification. We examined the role of the MMP-2 and MMP-9 in uraemic vascular calcification in vivo and in vitro. The impact of pharmacological MMP inhibition on the development of media calcifications was explored in an aggressive animal model of uraemic calcification. In addition, the selective effects of addition and inhibition, respectively, of MMP-2 and MMP-9 on calcium-/phosphate-induced calcifications were studied in a murine cell line of vascular smooth muscle cells (VSMCs). High-dose calcitriol treatment of uraemic rats given a high phosphate diet induced massive calcifications, apoptosis and increased gene expressions of MMP-2, MMP-9 and of osteogenic transcription factors and proteins in aortic VSMC. The MMP inhibitor doxycycline prevented the VSMC transdifferentiation to osteoblastic cells, suppressed transcription of mediators of matrix remodelling and almost completely blocked aortic calcifications while further increasing apoptosis. Similarly, specific inhibitors of either MMP-2 or -9, or of both gelatinases (Ro28-2653) and a selective knockdown of MMP-2/-9 mRNA expression blocked calcification of murine VSMC induced by calcification medium (CM). In contrast to MMP inhibition, recombinant MMP-2 or MMP-9 enhanced CM-induced calcifications and the secretion of gelatinases. These data indicate that both gelatinases provide essential signals for phenotypic VSMC conversion, matrix remodelling and the initiation of vascular calcification. Their inhibition seems a promising strategy in the prevention of vascular calcifications. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  9. Apoptosis and calcification of vascular endothelial cell under hyperhomocysteinemia.

    PubMed

    Fang, Kuaifa; Chen, Zhujun; Liu, Meng; Peng, Jian; Wu, Pingsheng

    2015-01-01

    In recent years, it is found that increase in Hcy level in blood can directly or indirectly cause vascular endothelial cell injury and induce vascular calcification. However, the mechanism of vascular endothelial cell injury and vascular calcification has not been studied thoroughly. This paper carried out experiment for research aiming at discussing the effect and action mechanism of Hhcy on endothelial cells and vascular calcification. Firstly, human umbilical vein endothelial cells (HUVECs) were cultured and then intervened by Hcy of different concentrations (0, 0.01, 0.1, 1.0, 3.0, 5.0 mmol/L) and at different action time (3, 6, 12, 24 h). Then apoptosis rate and reactive oxygen were detected by flow cytometry. At the same time, the model for the culture of rat vascular calcification was set up and induced into Hhcy so as to detect the total plasma Hcy level and judge vascular calcification degree. The results showed that with the increase in Hcy concentration and extension of action period, the apoptosis rate and generation of reactive oxygen of HUVECs all significantly increased, and the differences were all statistically significant (P < 0.01). In animal calcification model, mass of black particle deposition was seen after Von Kossa staining of rat vessels in calcification group. Compared with the control group, the vascular calcium content, alkaline phosphatase activity and osteocalcin content in calcification group all increased (P < 0.01). The content of plasma lipid conjugated olefine from highest to lowest wasas follows: calcification plus homoetheionin, homoetheionin, and calcification group. There was no significant difference between the calcification group and control group. All these findings suggested that Hcy could induce the apoptosis of endothelial cells and its effect degree depended on its concentration and action period; Hhcy could promote the calcification of blood vessels, and its mechanism might relate with the strengthening of

  10. 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.

  11. 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

  12. Inhibitory role of Notch1 in calcific aortic valve disease.

    PubMed

    Acharya, Asha; Hans, Chetan P; 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.

  13. Vascular calcification in patients with chronic kidney disease.

    PubMed

    Nitta, Kosaku

    2011-12-01

    Vascular calcification is very prevalent in patients with chronic kidney disease (CKD). In addition to having more traditional cardiovascular (CV) risk factors, CKD patients also have a number of non-traditional CV risk factors that may play a prominent role in the pathogenesis of vascular calcification. The transformation of vascular smooth muscle cells into osteoblast-like cells seems to be a key element in the pathogenesis of vascular calcification in the presence of calcium (Ca) and phosphorus (P) deposition due to abnormal bone metabolism and impaired renal excretion. Vascular calcification causes increased arterial stiffness, left ventricular hypertrophy, decreased coronary artery perfusion, myocardial ischemia, and increased cardiovascular morbidity and mortality. Although current treatment strategies focus on correcting abnormal Ca, P, parathyroid hormone, or vitamin D levels in CKD, a better understanding of the mechanisms of abnormal tissue calcification may lead to the development of new therapeutic agents that are capable of reducing vascular calcification and improving the CV outcome of CKD patients. This review article summarizes the following: (i) the pathophysiological mechanism responsible for vascular calcification; (ii) the methods of detecting vascular calcification in CKD patients; and (iii) the treatment of vascular calcification in CKD patients. © 2011 The Author. Therapeutic Apheresis and Dialysis © 2011 International Society for Apheresis.

  14. Roles of High Mobility Group Box 1 in Cardiovascular Calcification.

    PubMed

    Chen, Qiang; Wang, Ze-Yang; Chen, Li-Yuan; Hu, Hou-Yuan

    2017-01-01

    Calcific disease of the cardiovascular system, including atherosclerotic calcification, medial calcification in diabetes and calcific aortic valve disease, is an important risk factor for many adverse cardiovascular events such as ischemic cardiac events and subsequent mortality. Although cardiovascular calcification has long been considered to be a passive degenerative occurrence, it is now recognized as an active and highly regulated process that involves osteochondrogenic differentiation, apoptosis and extracellular vesicle release. Nonetheless, despite numerous studies on the pathogenesis of cardiovascular calcification, the underlying mechanisms remain poorly understood. High mobility group box 1 (HMGB1), a nuclear protein bound to chromatin in almost all eukaryotic cells, acts as a damage-associated molecular pattern (DAMP) when released into the extracellular space upon cell activation, injury or death. Moreover, HMGB1 also functions as a bone-active cytokine participating in bone remodeling and ectopic calcification pathogenesis. However, studies on the roles of HMGB1 in promoting cardiovascular calcification are limited to date, and the mechanisms involved are still unclear. In this review, we summarize recent studies investigating the mechanism of cardiovascular calcification and discuss multiple roles of HMGB1 in its development. © 2017 The Author(s). Published by S. Karger AG, Basel.

  15. The dualistic role of vitamin D in vascular calcifications

    PubMed Central

    Razzaque, M. Shawkat

    2011-01-01

    Vitamin D is a multifunctional hormone that can affect many essential biological functions, ranging from the immune regulation to mineral ion metabolism. A close association between altered activity of vitamin D and vascular calcification has been reported in various human diseases, including in patients with atherosclerosis, osteoporosis, and chronic kidney disease (CKD). Vascular calcification is a progressive disorder and is a major determinant of morbidity and mortality of the affected patients. Experimental studies have shown that excessive vitamin D activities can induce vascular calcification, and such vascular pathology can be reversed by reducing vitamin D activities. The human relevance of these experimental studies is not clear, as vitamin D toxicity is relatively rare in the general population. Contrary to the relationship between vitamin D and vascular calcification, in experimental uremic models, low levels of vitamin D were shown to be associated with extensive vascular calcification, a phenomenon that is very similar to the vascular pathology seen in patients with CKD. The current treatment approach of providing vitamin D analogs to patients with CKD often poses a dilemma, as studies linked vitamin D treatment to subsequent vascular calcification. Recent genetic studies, however, have shown that vascular calcification can be prevented by reducing serum phosphate levels, even in the presence of extremely high serum 1,25-dihydroxyvitamin D and calcium levels. This article will briefly summarize the dual effects of vitamin D in vascular calcification and will provide evidence of vitamin D-dependent and -independent vascular calcification. PMID:20962746

  16. Chronic parotitis with multiple calcifications: Clinical and sialendoscopic findings.

    PubMed

    Jáuregui, Emmanuel; Kiringoda, Ruwan; Ryan, William R; Eisele, David W; Chang, Jolie L

    2017-07-01

    To characterize clinical, imaging, and sialendoscopy findings in patients with chronic parotitis and multiple parotid calcifications. Retrospective review. Clinical history, radiographic images and reports, lab tests, and operative reports were reviewed for adult patients with chronic parotitis and multiple parotid calcifications who underwent parotid sialendoscopy. Thirteen of 133 (10%) patients undergoing parotid sialendoscopy for chronic sialadenitis had more than one calcification in the region of the parotid gland. Seven patients (54%) were diagnosed with immune-mediated disease from autoimmune parotitis (positive Sjögren's antibodies or antinuclear antibodies) or human immunodeficiency virus (HIV) disease. The six patients (46%) who did not have an immune-mediated disorder had most calcifications located anterior or along the masseter muscle. Eight of 13 patients (61%) had at least one calculus found in the parotid duct on sialendoscopy. Four patients (38%) had multiple punctate calcifications within the parotid gland, all of whom had either autoimmune parotitis or HIV. None of the proximal or punctate parotid calcifications posterior to the masseter were visualized on sialendoscopy. Chronic parotitis in conjunction with multiple parotid calcifications is uncommon and was identified in 10% of our cohort. We contrast two classifications of parotid calcifications: 1) intraductal stones that cause recurrent duct obstruction and are often located within the main parotid duct along or anterior to the masseter and 2) punctate intraparenchymal parotid gland calcifications that are not visualized on sialendoscopy and may represent underlying inflammatory disease. 4 Laryngoscope, 127:1565-1570, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  17. Influence of imperfections on effective properties of cellular solids

    SciTech Connect

    Grenestedt, J.L.

    1998-12-31

    The mechanical properties of cellular solids, or solid foams, is affected by imperfections such as wavy distortions of cell walls, variations in cell wall thickness, non-uniform cell shape, etc. The present paper is focused mainly on elastic stiffnesses of closed cell cellular solids. A perfect model is first discussed and shown to predict the behavior of PVC foams well. However, this model over-estimates the stiffnesses of aluminum foams. The relatively poor properties of the aluminum foam are believed to be caused by imperfections in the cells. The main body of the paper focuses on modeling different kinds of imperfections, and analyzing their impact on foam properties.

  18. [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.

  19. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  1. 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.

  2. 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

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

    PubMed

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

    2016-01-01

    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. 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. 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. 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.

  4. 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

  5. Influence of initial flaws on the mechanical properties of nacre.

    PubMed

    Anup, S

    2015-06-01

    Nacre is a bio-composite made up of hard mineral and soft protein, and has excellent mechanical properties. This paper examines the effect of naturally occurring defects (initial flaws) in nacre on its mechanical properties such as toughness and strength. A random fuse model is developed incorporating initial flaws. Numerical simulations show that initial flaws affect different mechanical properties at different rates. The variation in the experimentally obtained mechanical properties of nacre reported in the literature is shown to be due to initial flaws. The stress in the mineral and protein increases due to initial flaws, but by different amounts. The results obtained in this study are useful for gaining insight into the failure of nacre and development of nacre-inspired composites.

  6. The influence of propolis on rheological properties of lipstick.

    PubMed

    Goik, U; Ptaszek, A; Goik, T

    2015-08-01

    The aim of this work was to study the effect of propolis on the rheological and textural properties of lipsticks. The studied lipsticks were based on raw materials and contained no synthetic compounds, preservatives, fragrances or dyes. The rheological and textural properties of the prepared lipsticks, both with and without propolis, were studied as a function of temperature and storage period. Measurements were taken using an RS6000 rheometer (Haake, Germany) with a cone-plate sensor. The cone parameters were as follows: diameter 35 mm and angle 2°. Textural tests were performed using the same cone-plate geometry. The research results of rheological and textural properties of lipsticks, with and without the addition of propolis, indicate the possibility of application of propolis as a beneficial additive to such type of cosmetics. The presence of propolis does not significantly alter the viscoelastic properties of the lipsticks. The courses of flow curves indicate shear thinning, which is very advantageous from an application point of view. From the rheological point of view, the properties of lipsticks tested in low deformation conditions show some structural changes, most likely due to consolidation of the structure. The analysis of textural properties indicates that lipsticks with added propolis are more brittle and prone to crushing. However, the temperature increase (30°C) does not cause significant changes to the textural characteristics of these lipsticks. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  7. 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

  8. Factors influencing property selection for conservation revolving funds.

    PubMed

    Hardy, Mathew J; Fitzsimons, James A; Bekessy, Sarah A; Gordon, Ascelin

    2017-07-20

    Finding sustainable ways to increase the amount of private land protected for biodiversity is a challenge for many conservation organizations. In a number of countries, organizations use 'revolving fund' programs, whereby land is purchased, and then on-sold to conservation-minded owners with a condition to enter into a conservation covenant or easement. The proceeds from sale are then used to purchase, protect and on-sell additional properties, incrementally increasing the amount of protected private land. As the effectiveness of this approach relies upon selecting the right properties, we sought to explore the factors currently considered by practitioners and how these are integrated into decision-making. We conducted exploratory, semi-structured interviews with managers from each of the five major revolving funds in Australia. Responses suggest that whilst conservation factors are important, financial and social factors are also highly influential, with a major determinant being whether the property can be on-sold within a reasonable timeframe, and at a price that replenishes the fund. To facilitate the on-sale process, often selected properties include the potential for the construction of a dwelling. Practitioners are faced with clear trade-offs between conservation, financial, amenity and other factors in selecting properties; and three main potential risks: difficulty recovering the costs of acquisition, protection, and resale; difficulty on-selling the property; and difficulty meeting conservation goals. Our findings suggest that the complexity of these decisions may be limiting revolving fund effectiveness. We draw from participant responses to identify potential strategies to mitigate the risks identified, and suggest that managers could benefit from a shared learning and adaptive approach to property selection given the commonalities between programs. Understanding how practitioners are dealing with complex decisions in the implementation of revolving

  9. 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

  10. Influence of Carbon Nanotube Characteristics on Macroscopic Fiber Properties.

    PubMed

    Tsentalovich, Dmitri E; Headrick, Robert J; Mirri, Francesca; Hao, Junli; Behabtu, Natnael; Young, Colin C; Pasquali, Matteo

    2017-10-06

    We study how intrinsic parameters of carbon nanotube (CNT) samples affect the properties of macroscopic CNT fibers with optimized structure. We measure CNT diameter, number of walls, aspect ratio, graphitic character, and purity (residual catalyst and non-CNT carbon) in samples from 19 suppliers; we process the highest quality CNT samples into aligned, densely packed fibers, by using an established wet-spinning solution process. We find that fiber properties are mainly controlled by CNT aspect ratio and that sample purity is important for effective spinning. Properties appear largely unaffected by CNT diameter, number of walls, and graphitic character (determined by Raman G/D ratio) as long as the fibers comprise thin few-walled CNTs with high G/D ratio (above ∼20). We show that both strength and conductivity can be improved simultaneously by assembling high aspect ratio CNTs, producing continuous CNT fibers with an average tensile strength of 2.4 GPa and a room temperature electrical conductivity of 8.5 MS/m, ∼2 times higher than the highest reported literature value (∼15% of copper's value), obtained without postspinning doping. This understanding of the relationship of intrinsic CNT parameters to macroscopic fiber properties is key to guiding CNT synthesis and continued improvement of fiber properties, paving the way for CNT fiber introduction in large-scale aerospace, consumer electronics, and textile applications.

  11. Biomarkers Associated with Vascular Calcification in Peritoneal Dialysis.

    PubMed

    Ramirez-Sandoval, Juan C; Casanova, Ivan; Villar, Alejandro; Gomez, F Enrique; Cruz, Cristino; Correa-Rotter, Ricardo

    2016-01-01

    ♦ Vascular calcification is strongly associated with cardiovascular disease and mortality. However, some factors related to vascular calcification in patients with end-stage renal disease receiving peritoneal dialysis (PD) remain unknown. This study aimed to evaluate the associations of osteoprotegerin (OPG), osteopontin (OPN), osteocalcin (OCN), fibroblast growth factor 23 (FGF-23), magnesium, and phosphate clearance with vascular calcification in PD subjects, assessed by plain radiographs. ♦ Simple vascular calcification scores (SVCS) obtained from plain X-rays of the pelvis and hands, and the Kauppila Index (KI) from lateral lumbar X-rays were assessed in 76 adults receiving PD for ≥ 6 months (43 women, median age 39 years, median time on PD 1.4 years). Levels of OPG, OPN, OCN, and FGF-23 were determined by luminometry. ♦ Serum OPG levels were higher in subjects with vascular calcification (n = 22 with SVCS > 3; n = 19 with KI > 7) compared with those with less calcification (p < 0.001). Spearman's correlation coefficients between OPG and SVCS and KI were r = 0.49 and r = 0.51, respectively (both p < 0.001). Subjects with vascular calcification had significantly lower renal phosphate clearance. Multiple regression analysis showed that vascular calcification assessed by SVCS was associated with age (r = 0.2, p = 0.042), diabetes mellitus (r = 2.4, p < 0.001), body mass index (BMI) (r = 0.09, p = 0.037), and OPG (r = 0.22, p = 0.001). Vascular calcification assessed by KI was associated with age (r = 0.16, p < 0.001), time on PD (r = 0.54, p = 0.001) and OPG (r = 0.08, p = 0.04). Osteocalcin, OPN, FGF-23, and magnesium were not associated with vascular calcification. ♦ Higher levels of OPG were consistently associated with vascular calcification in subjects on PD. Copyright © 2016 International Society for Peritoneal Dialysis.

  12. 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.

  13. 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.

  14. Adipocyte induced arterial calcification is prevented with sodium thiosulfate.

    PubMed

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

    2014-06-20

    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. 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. 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. High phosphorus induced calcification of mature adipocytes, and adipocytes exposed to elevated phosphorus can induce calcification of VSMC in a paracrine manner. Sodium thiosulfate inhibited this calcification and decreased the secretin of leptin and VEGF from adipocytes. These results suggest that adipocyte exposure to elevated phosphorus may be a

  15. The time of onset of abnormal calcification in spondylometaepiphyseal dysplasia, short limb-abnormal calcification type.

    PubMed

    Tüysüz, Beyhan; Gazioğlu, Nurperi; Ungür, Savaş; Aji, Dolly Yafet; Türkmen, Seval

    2009-01-01

    A 1-month-old boy with shortness of extremities on prenatal US was referred to our department with a provisional diagnosis of achondroplasia. His height was normal but he had short extremities and platyspondyly, premature carpal epiphyses on both hands, and short tubular bones with irregular metaphyses on radiographs. Re-evaluation of the patient at the age of 1 year revealed very short height and premature calcification of the costal cartilages and epiphyses. Spondylometaepiphyseal dysplasia (SMED), short limb-abnormal calcification type was diagnosed. This condition is a very rare autosomal recessively inherited disorder, and most of the patients die in early childhood due to neurological involvement. At the age of 2 years and 5 months, a CT scan showed narrowing of the cervical spinal canal. One month later he died suddenly because of spinal cord injury. In conclusion early diagnosis is very important because the recurrence risk is high and patients may die due to early neurological complications. The time of onset of abnormal calcifications, a diagnostic finding of the disease, is at the age of around 1 year in most patients. When abnormal calcifications are not yet present, but radiological changes associated with SMED are present, this rare disease must be considered.

  16. Mitral annular calcification and aortic valve calcification may help in predicting significant coronary artery disease.

    PubMed

    Acartürk, Esmeray; Bozkurt, Abdi; Cayli, Murat; Demir, Mesut

    2003-01-01

    Mitral annular calcification (MAC) and aortic valve calcification (AVC) are manifestations of atherosclerosis. To determine whether mitral annular calcification and aortic valve calcification detected by transthoracic echocardiography (TTE) might help in predicting significant coronary artery disease (CAD), 123 patients with significant CAD and 93 patients without CAD detected by coronary angiography were investigated. MAC and AVC identified CAD with a sensitivity and specificity of 60.2%, 55.9% and 74.8%, 52.7%, respectively, and with a negative and a positive predictive values of 51.5%, 64.3% and 61.3% and 67.6%, respectively. The positive predictive value of MAC was greater than gender, hypertension, and hypercholesterolemia. AVC showed a positive predictive value greater than gender, hypertension, family history, and hypercholesterolemia. The negative predictive values of MAC and AVC for CAD were greater than those of all risk factors except diabetes mellitus. In conclusion, presence of MAC and AVC on TTE may help in predicting CAD and should be added to conventional risk factors. Absence of MVC and AVC is a stronger predictor for absence of CAD than all conventional risk factors, except diabetes mellitus. Patients with MAC and AVC should be taken into consideration for the presence of significant CAD and thereby for diagnostic and therapeutic interventions in order to improve the prognosis.

  17. 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.

  18. Harvest influences on floodwater properties in a forested floodplain

    Treesearch

    R. G. Clawson; B. G. Lockaby; R. B. Rummer

    1999-01-01

    Floodplain forests directly influence water quality by serving as sinks, sources, or transformers of nutrients. Increases in the demand for timber raise the question of how silvicultural disturbance may affect this function. The objective of this research was to compare biogeochemical relationships between undisturbed vs. disturbed conditions in a floodplain forest. A...

  19. Harvest Influences on Floodwater Properties in a Forested Floodplain

    Treesearch

    R.G. Clawson; B.G Lockaby; R.B. Rummer

    1999-01-01

    Abstract: Floodplain forests directly influence water quality by serving as sinks, sources, or transformers of nutrients. Increases in the demand for timber raise the question of how silvicultural disturbance may affect this function. The objective of this research was to compare biogeochemical relationships between undisturbed vs. disturbed...

  20. Association of conjunctival and corneal calcification with vascular calcification in dialysis patients.

    PubMed

    Seyahi, Nurhan; Altiparmak, Mehmet R; Kahveci, Arzu; Yetik, Huseyin; Kanberoglu, Kaya; Serdengecti, Kamil; Ataman, Rezzan; Erek, Ekrem

    2005-03-01

    Conjunctival and corneal calcification (CCC) is a well-known and easily detectable extraskeletal calcification, but its association with vascular calcification was not investigated previously. The aim of this study is to investigate the relationship of CCC with vascular calcification and bone metabolism parameters in dialysis patients. We evaluated 63 patients (30 men, 33 women; mean age, 43.5 +/- 13.4 years) who were on dialysis therapy for more than 6 months. Forty-four patients were on peritoneal dialysis and 19 patients were on hemodialysis therapy. The same observer evaluated the presence of CCC by using a slit-lamp microscope, and a total CCC score was recorded for each patient. Fifty-two age- and sex-matched healthy controls also were evaluated by using the same method. Biochemical data were collected from patient files. Bone mineral density (BMD) of the lumbar spine and femoral neck was measured, and the presence of vascular calcification was assessed by using x-ray examinations of the pelvis and hands. Mean CCC score in patients was significantly higher than that in controls (6.2 +/- 5.1 versus 1.3 +/- 1.8; P = 0.001). CCC score correlated significantly with duration of renal replacement therapy ( r s = 0.392; P = 0.002), serum phosphorus level ( r s = 0.259; P = 0.042), and calcium x phosphorus product ( r s = 0.337; P = 0.007). However, we did not find a significant correlation with calcium, parathyroid hormone, alkaline phosphatase, albumin, or C-reactive protein level or BMD. The frequency of vascular calcification was significantly greater in patients with a high CCC score (CCC score > or = 10) compared with a low CCC score (< or =3; 56.3% versus 5.6%; P = 0.002). Evaluation of CCC score is an easy, fast, and noninvasive method. It seems that CCC score can be used as an additional tool to assess the status of extraskeletal calcification in dialysis patients.

  1. Identification of breast calcification using magnetic resonance imaging

    SciTech Connect

    Fatemi-Ardekani, Ali; Boylan, Colm; Noseworthy, Michael D.

    2009-12-15

    MRI phase and magnitude images provide information about local magnetic field variation ({Delta}B{sub 0}), which can consequently be used to understand tissue properties. Often, phase information is discarded. However, corrected phase images are able to produce contrast as a result of magnetic susceptibility differences and local field inhomogeneities due to the presence of diamagnetic and paramagnetic substances. Three-dimensional (3D) susceptibility weighted imaging (SWI) can be used to probe changes in MRI phase evolution and, subsequently, result in an alternate form of contrast between tissues. For example, SWI has been useful in the assessment of negative phase induced {Delta}B{sub 0} modulation due to the presence of paramagnetic substances such as iron. Very little, however, has been done to assess positive phase induced contrast changes resulting from the presence of diamagnetic substances such as precipitated calcium. As ductal carcinoma in situ, which is the precursor of invasive ductal cancer, is often associated with breast microcalcification, the authors proposed using SWI as a possible visualization technique. In this study, breast phantoms containing calcifications (0.4-1.5 mm) were imaged using mammography, computed tomography (CT), and SWI. Corrected phase and magnitude images acquired using SWI allowed identification and correlation of all calcifications seen on CT. As the approach is a 3D technique, it could potentially allow for more accurate localization and biopsy and maybe even reduce the use of gadolinium contrast. Furthermore, the approach may be beneficial to women with dense breast tissue where the ability to detect microcalcification with mammography is reduced.

  2. Intracranial Carotid Calcification on Cranial Computed Tomography

    PubMed Central

    Subedi, Deepak; Zishan, Umme Sara; Chappell, Francesca; Gregoriades, Maria-Lena; Sudlow, Cathie; Sellar, Robin

    2015-01-01

    Background and Purpose— Intracranial internal carotid artery calcification is associated with cerebrovascular risk factors and stroke, but few quantification methods are available. We tested the reliability of visual scoring, semiautomated Agatston score, and calcium volume measurement in patients with recent stroke. Methods— We used scans from a prospective hospital stroke registry and included patients with anterior circulation ischemic stroke or transient ischemic stroke whose noncontrast cranial computed tomographic scans were available electronically. Two raters measured semiautomatic quantitative Agatston score, and calcium volume, and performed qualitative visual scoring using the original 4-point Woodcock score and a modified Woodcock score, where each image on which the internal carotid arteries appeared was scored and the slice scores summed. Results— Intra- and interobserver coefficient of variations were 8.8% and 16.5% for Agatston, 8.8% and 15.5% for calcium volume, and 5.7% and 5.4% for the modified Woodcock visual score, respectively. The modified Woodcock visual score correlated strongly with both Agatston and calcium volume quantitative measures (both R2=0.84; P<0.0001); calcium volume increased by 0.47-mm/point increase in modified Woodcock visual score. Intracranial internal carotid artery calcification increased with age by all measures (eg, visual score, Spearman ρ=0.4; P=0.005). Conclusions— Visual scores correlate highly with quantitative intracranial internal carotid artery calcification measures, with excellent observer agreements. Visual intracranial internal carotid artery scores could be a rapid and practical method for epidemiological studies. PMID:26251250

  3. 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

  4. Flax Fiber Quality and Influence on Interfacial Properties of Composites.

    USDA-ARS?s Scientific Manuscript database

    Measured flax physical and chemical properties could potentially impact binding and thus the stress transfer between the matrix and fiber. The study included 14 linseed samples with 12 samples ranging in cleanliness and retting produced using hammer mill technology from 2000, 2006 and 2007 with 2 sa...

  5. Mechanical properties that influence antimicrobial peptide activity in lipid membranes.

    PubMed

    Marín-Medina, Nathaly; Ramírez, Diego Alejandro; Trier, Steve; Leidy, Chad

    2016-12-01

    Antimicrobial peptides are small amphiphilic proteins found in animals and plants as essential components of the innate immune system and whose function is to control bacterial infectious activity. In order to accomplish their function, antimicrobial peptides use different mechanisms of action which have been deeply studied in view of their potential exploitation to treat antibiotic-resistant bacterial infections. One of the main mechanisms of action of these peptides is the disruption of the bacterial membrane through pore formation, which, in some cases, takes place via a monomer to oligomer cooperative transition. Previous studies have shown that lipid composition, and the presence of exogenous components, such as cholesterol in model membranes or carotenoids in bacteria, can affect the potency of distinct antimicrobial peptides. At the same time, considering the membrane as a two-dimensional material, it has been shown that membrane composition defines its mechanical properties which might be relevant in many membrane-related processes. Nevertheless, the correlation between the mechanical properties of the membrane and antimicrobial peptide potency has not been considered according to the importance it deserves. The relevance of these mechanical properties in membrane deformation due to peptide insertion is reviewed here for different types of pores in order to elucidate if indeed membrane composition affects antimicrobial peptide activity by modulation of the mechanical properties of the membrane. This would also provide a better understanding of the mechanisms used by bacteria to overcome antimicrobial peptide activity.

  6. Influence of wheat kernel physical properties on the pulverizing process.

    PubMed

    Dziki, Dariusz; Cacak-Pietrzak, Grażyna; Miś, Antoni; Jończyk, Krzysztof; Gawlik-Dziki, Urszula

    2014-10-01

    The physical properties of wheat kernel were determined and related to pulverizing performance by correlation analysis. Nineteen samples of wheat cultivars about similar level of protein content (11.2-12.8 % w.b.) and obtained from organic farming system were used for analysis. The kernel (moisture content 10 % w.b.) was pulverized by using the laboratory hammer mill equipped with round holes 1.0 mm screen. The specific grinding energy ranged from 120 kJkg(-1) to 159 kJkg(-1). On the basis of data obtained many of significant correlations (p < 0.05) were found between wheat kernel physical properties and pulverizing process of wheat kernel, especially wheat kernel hardness index (obtained on the basis of Single Kernel Characterization System) and vitreousness significantly and positively correlated with the grinding energy indices and the mass fraction of coarse particles (> 0.5 mm). Among the kernel mechanical properties determined on the basis of uniaxial compression test only the rapture force was correlated with the impact grinding results. The results showed also positive and significant relationships between kernel ash content and grinding energy requirements. On the basis of wheat physical properties the multiple linear regression was proposed for predicting the average particle size of pulverized kernel.

  7. Influence of isopropanol on ferroelectric properties of triglycine sulfate crystals

    NASA Astrophysics Data System (ADS)

    Milovidova, S. D.; Rogazinskaya, O. V.; Sidorkin, A. S.; Nguen, Kh. T.; Bykova, A. V.

    2015-03-01

    The dielectric and switching properties of triglycine sulfate (TGS) crystals grown from aqua solution with isopropanol have been studied. It has been shown that their behavior has common features with the behavior of the TGS crystals irradiated by X-rays, and also with the TGS crystals doped with L, α-alanine.

  8. 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

  9. [Celiac disease, cerebral calcifications and epilepsy syndrome].

    PubMed

    Cuvellier, J C; Vallée, L; Nuyts, J P

    1996-10-01

    The syndrome of coeliac disease, epilepsy and cerebral calcifications is a rare complication of coeliac disease. The pathological changes consist in a patchy pial angiomatosis and resemble those of Sturge-Weber syndrome, whose variant without port-wine angioma must be ruled out. Typical course includes three stages leading to a severe encephalopathy. However, the mental impairment is extremely variable. The pathogenetic process is so for unknown; main clues involve a chronic folic acid deficiency or a HLA-related autoimmune disorder. Treatment requires early gluten-free diet and anti-epileptic drug.

  10. Calcific tendinopathy of the rotator cuff tendons.

    PubMed

    Oliva, Francesco; Via, Alessio Giai; Maffulli, Nicola

    2011-09-01

    Calcific tendinopathy (CT) of the tendons of the rotator cuff is common in white populations, with a reported prevalence varying from 2.7% to 22%, mostly affecting women between 30 and 50 years. Although CT shows a strong tendency toward self-healing by spontaneous resorption of the deposits, it does not always follow this typical pattern. The etiopathogenesis of CT is still unknown. Many pathogenetic theories have been proposed, and clinical associations between CT and diabetes and thyroid disorders have been reported. The choice of therapeutic approach should depend on the evolution of the condition.

  11. Fiber properties and their influence on paper structure

    NASA Astrophysics Data System (ADS)

    Turrado Saucedo, Jose; Ramirez P., R.; Perez R., S.

    1997-08-01

    When we move our considerations of the components of paper, through the manufacture of paper, to the use of paper, we are analyzing the fundamental properties of paper related to its end uses. Paper as a product has a lot of possible uses and they are increasing, nevertheless it is very important in secondary products like corrugated board, etc. Every year the paper world production has an increase of approximately 1.6%. For the year 1994 it was 268,772,000 tons and during 1995 this production was 277,791,000 t. In Mexico for instance in 1994/2,860,162 tons and 1995/3,047,153 tons plus paper importation is possible to reach a per capita consumption of 35.8 kg. All paper quality kinds demand some special paper properties, which require technology, human resources and fibers properties. Surely there are fields to investigate by comparing the fundamental properties of paper and board with those of other materials, that is the reason why research must be done, despite the recent difficult times. In hard times its done distinction on switch of founds from fundamental to applied research and research for immediate development, this is understandable. Nevertheless, to study the relation between fibers and end use performance could well capture and even create a yet unknown market. Rather than adopt the attitude that 'here is paper, let us find markets for it' such research into the fundamental properties of the product will give one a clearer understanding of how it can satisfy future demands and meet possible future specifications. Because it is in meeting these specifications that the future of the industry must depend, it must be clear that money spent in this way now may not produce immediate quantifiable benefits, but it will produce the essential reserves that will in future be turned to good account by the industry.

  12. Coronary artery calcification correlates with the presence and severity of valve calcification.

    PubMed

    Koulaouzidis, G; Nicoll, R; MacArthur, T; Jenkins, P J; Henein, M Y

    2013-10-15

    To investigate the prevalence of coronary artery calcification (CAC) in symptomatic individuals with CT evidence for left heart valve calcification, aortic valve (AVC), mitral valve (MAC) or both. This is a retrospective study of 282 consecutive patients with calcification in either the aortic valve or mitral annulus. Calcium scoring of the coronary artery, aortic and mitral valve was measured using the Agatston score. AVC was more prevalent than MAC (64% vs. 2.5%, p < 0.001), with 34% having both. Absence of CAC was noted in 12.7% of the study population. AVC + CAC were observed in 53.5%, MAC and CAC in 2.1%, and combined AVC, MAC and CAC in 31.6%. The median CAC score was higher in individuals with combined AVC+MAC, followed by those with AVC and lowest was in the MAC group. The majority (40%) of individuals with AVC had CAC score >400, and only in 16% had CAC = 0. The same pattern was more evident in individuals with AVC + MAC, where 70% had CAC score >400 and only 6% had CAC score of 0. These results were irrespective of gender. There was no correlation between AVC and MAC but there was modest correlation between CAC score and AVC score (r = 0.28, p = 0.0001), MAC (r = 0.36, p = 0.0001) and with combined AVC + MAC (r = 0.5, p = 0.0001). AVC score of 262 had a sensitivity of 78% and specificity of 92% for the prediction of presence of CAC. The presence and extent of calcification in the aortic valve or/and mitral valves are associated with severe coronary artery calcification. © 2013.

  13. Expression of NPP1 is regulated during atheromatous plaque calcification

    PubMed Central

    Nitschke, Yvonne; Hartmann, Simone; Torsello, Giovanni; Horstmann, Rüdiger; Seifarth, Harald; Weissen-Plenz, Gabriele; Rutsch, Frank

    2011-01-01

    Abstract Mutations of the ENPP1 gene encoding ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1) are associated with medial calcification in infancy. While the inhibitory role of matrix proteins such as osteopontin (OPN) with respect to atherosclerotic plaque calcification has been established, the role of NPP1 in plaque calcification is not known. We assessed the degree of plaque calcification (computed tomography), NPP1 and OPN localization (immunohistochemistry) and expression (RT-PCR) in a cohort of 45 patients undergoing carotid endatherectomy for significant stenosis of the internal carotid artery and in normal arteries (N= 50). We correlated NPP1 and OPN expression levels to the degree of plaque calcification, to pro-atherogenic factors and statin therapy. NPP1 was demonstrated in the base and in the shoulder of atherosclerotic plaques. Compared to normal arteries and non-calcified plaques, in calcified plaques NPP1 mRNA was decreased (P < 0.0001). OPN mRNA levels were up-regulated in carotid atheroma. NPP1 and OPN expression levels positively correlated with the degree of plaque calcification (R= 0.54, P= 0.00019 and R= 0.46, P= 0.017, respectively) and with risk factors of atherosclerosis. Expression of the calcification inhibitor NPP1 is down-regulated in calcified atherosclerotic plaques. Our correlation data point to a counter-active mechanism, which in the end turns out to be insufficient to prevent further progression of calcification. PMID:20015201

  14. Presternal soft tissue calcifications following mediastinal radiotherapy for Hodgkin's disease

    SciTech Connect

    Vainright, J.R.; Diaconis, J.N.; Haney, P.J.

    1987-01-01

    A patient is described in whom dense calcifications developed in the presternal soft tissues of the chest four years after mediastinal radiotherapy. This is believed to represent dystrophic calcification in previously normal but incidentally radiated tissues following standard dose radiotherapy to the mediastinum for stage IIA Hodgkin's disease.

  15. Pineal calcification is associated with pediatric primary brain tumor.

    PubMed

    Tuntapakul, Supinya; Kitkhuandee, Amnat; Kanpittaya, Jaturat; Johns, Jeffrey; Johns, Nutjaree Pratheepawanit

    2016-12-01

    Melatonin has been associated with various tumors, including brain tumor, and shown to inhibit growth of neuroblastoma cells and gliomas in animal models. Likewise, patients with glioblastoma receiving melatonin reported better survival than controls. Pineal calcification may lead to a decreased production of melatonin by calcified glands. This study assessed association between pineal calcification and primary brain tumor in pediatric/adolescent patients. Medical chart review was conducted in 181 patients <15 years old who had undergone brain computed tomography (CT) during 2008-2012. Pineal calcification was identified using brain CT scan by an experienced neurosurgeon. Primary brain tumor was confirmed by CT scan and histology, and association with pineal calcification was estimated using multiple logistic regression, adjusted for age and gender. Primary brain tumor was detected in 51 patients (mean age 9.0, standard deviation 4.0 years), with medulloblastoma being the most common (11 patients). Pineal calcification was detected in 12 patients (23.5%) with primary brain tumor, while only 11 patients (8.5%) without tumor had pineal calcification. Adjusted for patients' ages and genders, pineal calcification was associated with an increase in primary brain tumor of 2.82-fold (odds ratio 2.82; 95% confidence interval 1.12-7.08, P = 0.027). Pineal calcification appears to be associated with primary brain tumor. Further studies to explore this link are discussed and warranted. © 2016 John Wiley & Sons Australia, Ltd.

  16. Acromial morphology in patients with calcific tendinitis of the shoulder.

    PubMed

    Balke, Maurice; Banerjee, Marc; Vogler, Tim; Akoto, Ralph; Bouillon, Bertil; Liem, Dennis

    2014-02-01

    The purpose of this study was to evaluate whether the morphology of the acromion in calcific tendinitis differs from controls without subacromial pathology and matches subacromial impingement. Digital radiographs of 150 shoulders were evaluated with the open source DICOM-Viewer OsiriX. 50 patients had symptomatic calcific tendinitis of the shoulder, 50 had subacromial impingement without calcifications or rotator cuff tears, 50 with bruised shoulder that were previously asymptomatic served as controls. Acromial shape according to Bigliani et al. acromial tilt (AT) according to Kitay et al. and Aoki et al. acromion index (AI) according to Nyffeler et al. and lateral acromial angle (LAA) according to Banas et al. were measured. Both calcific (0.72; P = 0.001) and impingement groups (0.73; P = 0.008) were significantly different from controls (0.67) using AI measure, while only the calcific group (79.5°) was different from controls (84.1°) using LAA (P < 0.001), and only the impingement group (32.9°) was different from controls (29.2°) using AT (P < 0.001). An LAA <70° only occurred in two patients with calcific tendinitis. The hypothesis of this study was that the morphology of the acromion in calcific tendinitis differs from controls without subacromial pathology and matches subacromial impingement was only confirmed for the AI. The AI of shoulders with calcific tendinitis is comparable to that of shoulders with subacromial impingement.

  17. Evidence for a calcification process in the trabecular meshwork.

    PubMed

    Borrás, Teresa; Comes, Núria

    2009-04-01

    The human trabecular meshwork (TM) expresses many genes that have been associated with physiological (bone, cartilage, teeth) and pathological (vascular systems, kidney) calcification. In particular, the TM highly expresses the inhibitor of calcification Matrix Gla (MGP) gene, which encodes a vitamin K-dependent protein that requires post-translational activation to inhibit the formation of calcium precipitates. TM cells have high activity of the activating gamma-carboxylase enzyme and produce active MGP. Silencing MGP increases the activity of alkaline phosphatase (ALP), an enzyme of the matrix vesicles and marker of calcification. Overexpressing MGP reduces the ALP activity induced by bone morphogenetic 2 (BMP2), a potent inducer of calcification. In this review we gathered evidence for the existence of a mineralization process in the TM. We selected twenty regulatory calcification genes, reviewed their functions in their original tissues and looked at their relative abundance in the TM by heat maps derived from existing microarrays. Although results are not yet fully conclusive and more experiments are needed, examining TM expression in the light of the calcification literature brings up many similarities. One such parallel is the role of mechanical forces in bone induction and the high levels of mineralization inhibitors found in the constantly mechanically stressed TM. During the next few years, examination of other calcification-related regulatory genes and pathways, as well as morphological examination of knockout animals, would help to elucidate the relevance of a calcification process to TM's overall function.

  18. [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.

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

    USDA-ARS?s Scientific Manuscript database

    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. Left atrial calcification in a hemodialysis patient with cor triatriatum.

    PubMed

    Peces, R; Pobes, A; Rodriguez, M; Simarro, C; Iglesias, G; Simarro, E

    2000-05-01

    Myocardial calcification is a rare manifestation of abnormal calcium metabolism seen in some patients with chronic renal failure. This report describes the transesophageal echocardiographic and spiral computed tomography (CT) findings in a young hemodialysis female with severe secondary hyperparathyroidism. These findings included calcification of the multiperforated membrane of a cor triatriatum and the wall of the left atrium.

  1. Influence of osmolarity on the optical properties of human erythrocytes.

    PubMed

    Friebel, Moritz; Helfmann, Jürgen; Meinke, Martina C

    2010-01-01

    Plasma osmolarity influences the volume and shape of red blood cells (RBCs). The volume change is inversely related to the hemoglobin concentration and as a consequence to the complex refractive index within the cell. These morphological changes can be linked to changes in the optical behavior of the cells. The optical parameters, absorption coefficient μa, scattering coefficient μs, and effective scattering phase function of red blood cells are investigated in dependence on osmolarity in the spectral range from 250 to 1100 nm. Integrating sphere measurements of light transmittance and reflectance in combination with inverse Monte-Carlo simulations are carried out for osmolarities from 225 to 400 mosmol/L. Osmolarity changes have a significant influence on the optical parameters, which can in part be explained by changes in the complex refractive index, cell shape, and cell volume. Spherical forms of RBCs induced by low osmolarity show reduced scattering effects compared to the normal RBC biconcave disk shape. Spinocytes, which are crenated erythrocytes induced by high osmolarity, show the highest scattering effects. Even only a 10% change in osmolarity has a drastic influence on the optical parameters, which appears to be of the same order as for 10% hematocrit and oxygen saturation changes.

  2. Influence of osmolarity on the optical properties of human erythrocytes

    NASA Astrophysics Data System (ADS)

    Friebel, Moritz; Helfmann, Jürgen; Meinke, Martina C.

    2010-09-01

    Plasma osmolarity influences the volume and shape of red blood cells (RBCs). The volume change is inversely related to the hemoglobin concentration and as a consequence to the complex refractive index within the cell. These morphological changes can be linked to changes in the optical behavior of the cells. The optical parameters, absorption coefficient μa, scattering coefficient μs, and effective scattering phase function of red blood cells are investigated in dependence on osmolarity in the spectral range from 250 to 1100 nm. Integrating sphere measurements of light transmittance and reflectance in combination with inverse Monte-Carlo simulations are carried out for osmolarities from 225 to 400 mosmol/L. Osmolarity changes have a significant influence on the optical parameters, which can in part be explained by changes in the complex refractive index, cell shape, and cell volume. Spherical forms of RBCs induced by low osmolarity show reduced scattering effects compared to the normal RBC biconcave disk shape. Spinocytes, which are crenated erythrocytes induced by high osmolarity, show the highest scattering effects. Even only a 10% change in osmolarity has a drastic influence on the optical parameters, which appears to be of the same order as for 10% hematocrit and oxygen saturation changes.

  3. Affective stimulus properties influence size perception and the Ebbinghaus illusion

    PubMed Central

    Semin, Gün R.; Oudejans, Raôul R. D.; Beek, Peter J.

    2007-01-01

    In the New Look literature of the 1950s, it has been suggested that size judgments are dependent on the affective content of stimuli. This suggestion, however, has been ‘discredited’ due to contradictory findings and methodological problems. In the present study, we revisited this forgotten issue in two experiments. The first experiment investigated the influence of affective content on size perception by examining judgments of the size of target circles with and without affectively loaded (i.e., positive, neutral, and negative) pictures. Circles with a picture were estimated to be smaller than circles without a picture, and circles with a negative picture were estimated to be larger than circles with a positive or a neutral picture confirming the suggestion from the 1950s that size perception is influenced by affective content, an effect notably confined to negatively loaded stimuli. In a second experiment, we examined whether affective content influenced the Ebbinghaus illusion. Participants judged the size of a target circle whereby target and flanker circles differed in affective loading. The results replicated the first experiment. Additionally, the Ebbinghaus illusion was shown to be weakest for a negatively loaded target with positively loaded and blank flankers. A plausible explanation for both sets of experimental findings is that negatively loaded stimuli are more attention demanding than positively loaded or neutral stimuli. PMID:17410379

  4. Influence of Barium Hexaferrite on Magnetic Properties of Hydroxyapatite Ceramics.

    PubMed

    Jarupoom, P; Jaita, P

    2015-11-01

    Hydroxyapatite (HA) powders was derived from natural bovine bone by sequence of thermal processes. The barium hexaferrite (BF) find magnetic powders were added into HA powders in ratio of 1-3 vol.%. The HA-BF ceramics were prepared by a solid state reaction method and sintered at 1250 degrees C for 2 h. Effects of BF additive on structural, physical and magnetic properties of HA ceramics were investigated. X-ray diffraction revealed that all HA-BF samples showed a main phase of high purity hydroxyapatite [Ca10(PO4)6(OH)2] with calcium and phosphate molar ratio of 1.67. The addition of BF into HA inhibited grain growth and caused an improvement of mechanical properties. The M-H hysteresis loops also showed an improvement in magnetic behavior for higher content of BF. Moreover, in vitro bioactivity test indicated that the 2-3 vol.% sample may be suitable for biological applications.

  5. 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.

  6. Influence of saturation properties on shell-model calculations

    NASA Astrophysics Data System (ADS)

    Abzouzi, A.; Caurier, E.; Zuker, A. P.

    1991-03-01

    It is shown that the nuclear Hamiltonian scrH separates rigorously into a monopole field scrHm and a multipole part scrHm. scrHm is entirely responsible for saturation properties and can be treated phenomenologically with few parameters. When realistic interactions are used for scrHM in regions from the p shell to the N=82 isotones, shell-model calculations yield excellent spectroscopy and demand nuclear radii very close to the observed ones.

  7. 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.

  8. Influence of oxygen on the optical properties of silver nanoparticles.

    PubMed

    Renteria-Tapia, V M; García-Macedo, J

    2008-12-01

    Silver nanoparticles in sol-gel silica films were obtained by annealing in hydrogen atmosphere and subsequently in oxygen atmosphere. Their properties were measured by UV-vis spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electronic microscopy (HRTEM) and X-ray diffraction analysis. Samples prepared in a reducing atmosphere exhibited a surface plasmon resonance (SPR) located at 399 nm. Silver nanoparticles in an oxidizing atmosphere exhibited a red shift and damping of the SPR. These optical properties were explained due to the oxidation on the surface of silver nanoparticles to silver oxide yield in an oxygen atmosphere. Silver core-silver oxide shell nanostructures were observed by HRTEM. The average size of the metallic nanoparticles obtained by TEM was used for modeling the UV-vis spectra by using the Gans theory. Good fits to the spectra under an oxidizing atmosphere were obtained considering variable refractive indexes coming from the silver oxide shells surrounding to the nanoparticles. Therefore, the interaction between oxygen and the metallic surface of the nanoparticles, sensitively alters their optical properties.

  9. 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.

  10. Properties Influencing Plasma Discharges in Packed Bed Reactors

    NASA Astrophysics Data System (ADS)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Kushner, Mark J.

    2016-09-01

    Atmospheric pressure dielectric barrier discharges (DBDs) sustained in packed bed reactors (PBRs) are being investigated for CO2 removal and conversion of waste gases into higher value compounds. We report on results of a computational investigation of PBR-DBD properties using the plasma hydrodynamics simulator nonPDPSIM with a comparison to experiments. Dielectric beads (rods in 2D) were inserted between two coplanar electrodes, 1 cm apart filled by humid air. A step-pulse of -30 kV was applied to the top electrode. Material properties of the beads (dielectric constant, secondary emission coefficient) and gas properties (photoionization and photo-absorption cross-sections, temperature) were varied. We found that photoionization plays a critical role in the propagation of the discharge through the PBR, as it serves to seed charges in regions of high electric field. Increasing rates of photo-ionization enable increases in the discharge propagation velocity, ionization rates and production of radicals. A transition between DBD-like and arc-like discharges occurs as the radiation mean free path decreases. Increasing the dielectric constant of the beads increased electric fields in the gas, which translated to increased discharge propagation velocity and charge density until ɛ/ɛ0 100. Secondary electron emission coefficient and gas temperature have minimal impacts on the discharge propagation though the latter did affect the production of reactive species. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  11. Influence of delayed pouring on irreversible hydrocolloid properties.

    PubMed

    Rodrigues, Stéfani Becker; Augusto, Carolina Rocha; Leitune, Vicente Castelo Branco; Samuel, Susana Maria Werner; Collares, Fabrício Mezzomo

    2012-01-01

    The aim of this study was to evaluate the physical properties of irreversible hydrocolloid materials poured immediately and after different storage periods. Four alginates were tested: Color Change (Cavex); Hydrogum (Zhermack); Hydrogum 5 (Zhermack); and Hydro Print Premium (Coltene). Their physical properties, including the recovery from deformation (n = 3), compressive strength (n = 3), and detail reproduction and gypsum compatibility (n = 3), were analyzed according to ANSI/ADA specification no. 18. Specimens were stored at 23ºC and humidity and were then poured with gypsum immediately and after 1, 2, 3, 4, and 5 days. The data were analyzed by two-way analysis of variance (ANOVA) and Tukey's test at p < 0.05. All of the alginate impression materials tested exhibited detail reproduction and gypsum compatibility at all times. Hydro Print Premium and Hydrogum 5 showed recovery from deformation, as established by ANSI/ADA specification no. 18, after 5 days of storage. As the storage time increased, the compressive strength values also increased. Considering the properties of compounds' recovery from deformation, compressive strength, and detail reproduction and gypsum compatibility, irreversible hydrocolloids should be poured immediately.

  12. 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

  13. [Diabetic angiopathy and the progression of vascular calcification].

    PubMed

    Kotake, Hidetoshi; Oikawa, Shinichi

    2003-09-01

    The frequency of atherosclerotic diseases in diabetes is very high. In the occurrence of atherosclerosis the severity of diabetes is not so important. The mild diabetic condition with obesity will be a strong factor to relate with atherogenesis. As mentioned above the atherogenesis in diabetes is slightly complicated, because multiple risk factors accumulate in diabetes mellitus. These factors are hyperglycemia, hyperlipidemia, hypertension, smoking, and obesity, It has been clarified that the mechanism of arterial calcification will be same as in bone calcification process which is regulated by the various bone metabolic factors. In diabetes mellitus the characteristic vascular changes is that there is multiple calcification in the various arteries including aorta, coronary artery, and peripheral arterioles. It is considered that the necrosis and apoptosis of vascular smooth muscle cells and the transforming of vascular cells to bone cell or cartilage cell are induced and related to arterial calcification. The other factor of calcification would be inflammatory changes related to atheroma formation.

  14. 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

  15. Influence of clearing solutions osmolarity on the optical properties of RBC

    NASA Astrophysics Data System (ADS)

    Zhestkov, Dmitry M.; Bashkatov, Alexey N.; Genina, Elina A.; Tuchin, Valery V.

    2004-08-01

    The possibility of immersion clearing of human blood in visible and NIR spectral range has been discussed. Based on presented model the spectral behavior of scattering and absorption characteristics of blood caused by immersion properties of glucose solution has been analyzed. The influence of osmotic properties of glucose solution on blood erythrocytes has been shown.

  16. 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…

  17. Environment and hybrid influences on rapid visco analysis starch properties of food-grade grain sorghum

    USDA-ARS?s Scientific Manuscript database

    Grain processors would benefit from information regarding production environment and sorghum hybrid influences on food-grade starch properties. The objective of this study was to determine the effects of environment and hybrid on Rapid Visco Analysis (RVA) starch properties of commercially available...

  18. 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…

  19. Influence of boric anhydride upon the physical and chemical properties of ferrosilicon slag

    NASA Astrophysics Data System (ADS)

    Yefimets, A. M.; Tesleva, E. P.; Solovyan, A. V.

    2015-09-01

    The authors study the influence of boric anhydride upon the physical and chemical properties of slag in the manufacture of ferrosilicon. It is established that adding boric anhydride to the slag changes its refractory quality and its viscosity and eases pouring slag and metal. Slags with optimal composition and properties are described.

  20. Calcific Uremic Arteriolopathy: An Underrecognized Entity

    PubMed Central

    Kumar, Victoria Ann

    2011-01-01

    Calcific uremic arteriolopathy (CUA), or calciphylaxis, is an uncommon and underrecognized disease that often occurs in the setting of chronic kidney disease or end-stage renal disease. It is characterized by small-vessel calcification, although many times it is associated with normal serum levels of calcium, phosphorus, and parathyroid hormone. The lesions appear as necrotic eschars, ulcerations, indurated nodules, and dry gangrene and are usually very painful. Diagnosis is based on clinical judgment and recognition of characteristic skin lesions. Biopsy can be performed but may be complicated by poor wound healing. Treatment of CUA involves rigorous wound care, strict control of mineral metabolism with avoidance of calcium and vitamin D analogs, and pain control. Other treatment options include sodium thiosulfate, hyperbaric oxygen therapy, daily hemodialysis using low-calcium dialysate, and bisphosphonates. Even with treatment, CUA is associated with significant morbidity and mortality. The patient in the case reported here had characteristic skin lesions and several risk factors for CUA, but diagnosis was delayed. PMID:21841931

  1. Vascular calcifications, vertebral fractures and mortality in haemodialysis patients

    PubMed Central

    Rodríguez-García, Minerva; Gómez-Alonso, Carlos; Naves-Díaz, Manuel; Diaz-Lopez, Jose Bernardino; Diaz-Corte, Carmen; Cannata-Andía, Jorge B.

    2009-01-01

    Background. Vascular calcifications and the bone fractures caused by abnormal bone fragility, also called osteoporotic fractures, are frequent complications associated with chronic kidney diseases (CKD). The aim of this study was to investigate the association between vascular calcifications, osteoporotic bone fractures and survival in haemodialysis (HD) patients. Methods. A total of 193 HD patients were followed up to 2 years. Vascular calcifications and osteoporotic vertebral fractures (quoted just as vertebral fractures in the text) were assessed by thoracic, lumbar spine, pelvic and hand X-rays and graded according to their severity. Clinical, biochemical and therapeutic data gathered during the total time spent on HD were collected. Results. The prevalence of aortic calcifications was higher in HD patients than in a random-based general population (79% versus 37.5%, P < 0.001). Total time on any renal replacement therapy (RRT) and diabetes were positively associated with a higher prevalence of vascular calcifications. In addition to these factors, time on HD was also positively associated with the severity of vascular calcifications, and higher haemoglobin levels were associated with a lower prevalence of severe vascular calcifications in large and medium calibre arteries. The prevalence of vertebral fractures in HD patients was similar to that of the general population (26.5% versus 24.1%). Age and time on HD showed a positive and statistically significant association with the prevalence of vertebral fractures. Vascular calcifications in the medium calibre arteries were associated with a higher rate of prevalent vertebral fractures. In women, severe vascular calcifications and vertebral fractures were positively associated with mortality [RR = 3.2 (1.0–10.0) and RR = 4.8 (1.7–13.4), respectively]. Conclusions. Positive associations between vascular calcifications, vertebral fractures and mortality have been found in patients on HD. PMID:18725376

  2. Fetuin-A Protects against Atherosclerotic Calcification in CKD

    PubMed Central

    Westenfeld, Ralf; Schäfer, Cora; Krüger, Thilo; Haarmann, Christian; Schurgers, Leon J.; Reutelingsperger, Chris; Ivanovski, Ognen; Drueke, Tilman; Massy, Ziad A.; Ketteler, Markus; Floege, Jürgen; Jahnen-Dechent, Willi

    2009-01-01

    Reduced serum levels of the calcification inhibitor fetuin-A associate with increased cardiovascular mortality in dialysis patients. Fetuin-A–deficient mice display calcification of various tissues but notably not of the vasculature. This absence of vascular calcification may result from the protection of an intact endothelium, which becomes severely compromised in the setting of atherosclerosis. To test this hypothesis, we generated fetuin-A/apolipoprotein E (ApoE)-deficient mice and compared them with ApoE-deficient and wild-type mice with regard to atheroma formation and extraosseous calcification. We assigned mice to three treatment groups for 9 wk: (1) Standard diet, (2) high-phosphate diet, or (3) unilateral nephrectomy (causing chronic kidney disease [CKD]) plus high-phosphate diet. Serum urea, phosphate, and parathyroid hormone levels were similar in all genotypes after the interventions. Fetuin-A deficiency did not affect the extent of aortic lipid deposition, neointima formation, and coronary sclerosis observed with ApoE deficiency, but the combination of fetuin-A deficiency, hyperphosphatemia, and CKD led to a 15-fold increase in vascular calcification in this model of atherosclerosis. Fetuin-A deficiency almost exclusively promoted intimal rather than medial calcification of atheromatous lesions. High-phosphate diet and CKD also led to an increase in valvular calcification and aorta-associated apoptosis, with wild-type mice having the least, ApoE-deficient mice intermediate, and fetuin-A/ApoE-deficient mice the most. In addition, the combination of fetuin-A deficiency, high-phosphate diet, and CKD in ApoE-deficient mice greatly enhanced myocardial calcification, whereas the absence of fetuin-A did not affect the incidence of renal calcification. In conclusion, fetuin-A inhibits pathologic calcification in both the soft tissue and vasculature, even in the setting of atherosclerosis. PMID:19389852

  3. Popcorn calcification in osteogenesis imperfecta: incidence, progression, and molecular correlation.

    PubMed

    Obafemi, Abimbola A; Bulas, Dorothy I; Troendle, James; Marini, Joan C

    2008-11-01

    Osteogenesis imperfecta (OI) is a heritable disorder characterized by osteoporosis and increased susceptibility to fracture. All children with severe OI have extreme short stature and some have "popcorn" calcifications, areas of disorganized hyperdense lines in the metaphysis and epiphysis around the growth plate on lower limb radiographs. Popcorn calcifications were noted on radiographs of two children with non-lethal type VIII OI, a recessive form caused by P3H1 deficiency. To determine the incidence, progression, and molecular correlations of popcorn calcifications, we retrospectively examined serial lower limb radiographs of 45 children with type III or IV OI and known dominant mutations in type I collagen. Popcorn calcifications were present in 13 of 25 type III (52%), but only 2 of 20 type IV (10%), OI children. The mean age of onset was 7.0 years, with a range of 4-14 years. All children with popcorn calcifications had this finding in their distal femora, and most also had calcifications in proximal tibiae. While unilateral popcorn calcification contributes to femoral growth deficiency and leg length discrepancy, severe linear growth deficiency, and metaphyseal flare do not differ significantly between type III OI patients with and without popcorn calcifications. The type I collagen mutations associated with popcorn calcifications occur equally in both COL1A1 and COL1A2, and have no preferential location along the chains. These data demonstrate that popcorn calcifications are a frequent feature of severe OI, but do not distinguish cases with defects in collagen structure (primarily dominant type III OI) or modification (recessive type VIII OI). Copyright 2008 Wiley-Liss, Inc.

  4. Influence of Through-Thickness Pinning on Composite Shear Properties

    NASA Astrophysics Data System (ADS)

    Maurin, Romain; Baley, Christophe; Cartié, Denis D. R.; Davies, Peter

    2012-12-01

    This paper describes results from tests to examine the influence of through-thickness pinning on in-plane shear behaviour, measured by tensile loading of ±45° specimens. Samples were produced by both aeronautical and marine manufacturing processes. As few previous studies have investigated pinning of marine composites these were also subjected to out-of-plane shear delamination tests. For both carbon/epoxy laminates the pins reduce the apparent in-plane shear modulus and strength. Pins modify the strain field measured by full-field image analysis, and slow damage development. A new damage mechanism, transverse pin cracking, was observed.

  5. Study of calcification during a daily cycle of the coral Stylophora pistillata: implications for 'light-enhanced calcification'.

    PubMed

    Moya, Aurélie; Tambutté, Sylvie; Tambutté, Eric; Zoccola, Didier; Caminiti, Natacha; Allemand, Denis

    2006-09-01

    This work, performed on the scleractinian coral Stylophora pistillata, aims at providing new information on the 'light-enhanced calcification' process. In a first step, in controlled conditions of culture and constant light supply, we studied the diurnal cycle of calcification. We determined that calcification rates are constant during the day and the night with a 2.6-fold difference between day and night calcification rates. We also showed that the photosynthetic rate is constant throughout the day when a constant light intensity is applied. Our results on free-running experiments in prolonged conditions of light or dark suggest that calcification is not regulated by an endogenous circadian rhythm. In a second step, using a kinetic isotopic approach with (45)Ca, we characterized the transition stages between day and night and vice versa. Under our experimental conditions, the lag-phase necessary to switch from the light to the dark calcification rate is the same as the lag-phase necessary to switch from the dark to the light calcification rate. We discuss our results in the context of two hypotheses of the light-enhanced calcification process: (1) the role of photosynthesis on the pH in the coelenteron and (2) the role of photosynthesis in supplying precursors of the organic matrix.

  6. 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.

  7. Influence of finishing on the electrochemical properties of dental alloys.

    PubMed

    Kaneko, T; Hattori, M; Hasegawa, K; Yoshinari, M; Kawada, E; Oda, Y

    2000-05-01

    Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the polarization resistance and potentiodynamic polarization profile of the precious-metal alloys, Type 4 gold alloy and silver-palladium alloy, and the base-metal alloys, nickel-chromium alloy, cobalt-chromium alloy, and CP-titanium. Three types of finishing procedure were examined: mirror-finishing using 0.05 micron alumina particles, polishing using #600 abrasive paper and sandblasting. Dissolution of the alloy elements in 0.9% NaCl solution was also measured and compared with the electrochemical evaluation. The corrosion resistance of the dental alloys was found to relate to finishing as follows: The polarization resistance and potentiodynamic polarization behavior revealed that the corrosion resistance improved in the order of sandblasting, #600-abrasive-paper polishing, and mirror-finishing. While the corrosion potential, critical current density and passive current density varied depending on the type of finishing, the transpassive potential remained unchanged. The influence of finishing on the corrosion resistance of precious-metal alloys was less significant than on that of base-metal alloys. A mirror-finishing specimen was recommended for use in evaluation of the corrosion resistance of various dental alloys.

  8. Probing the internal calcification chemistry of O. universa using B/Ca

    NASA Astrophysics Data System (ADS)

    Holland, K.; Eggins, S.; Hoenisch, B.; Haynes, L.; Russell, A. D.

    2014-12-01

    The B/Ca, U/Ca ratio values of calcitic foraminifer shells are all influenced by seawater carbonate chemistry (seawater [B(OH)4-/HCO3-], [CO32-], and pH respectively), and as such are increasingly being used as proxies to reconstruct past changes in ocean inorganic carbon content, saturation state and pH. However, the behavior of these proxies is subject to modification by foraminifers' efforts to regulate the conditions under which they grow their shells. We have undertaken experiments on Orbulina universa that manipulate synthetic culture water DIC, pH and [Ca] in an effort to disentangle the biological versus environmental influences of seawater carbonate system and saturation state on B/Ca, U/Ca and Mg/Ca ratio into foraminiferal calcite. Experiments were designed to be able determine the extent to which foraminifers are able to modify the chemical composition of their (vacuolized?) internal calcification fluid, in particular by using B/Ca and U/Ca as sensors for calcification chemistry (i.e. internal [B(OH)4-/HCO3-] and [CO32-]) . We have used a high resolution LA-ICPMS depth profiling techniques to characterize the amplitude of B/Ca, U/Ca, Mg/Ca, and Sr/Ca ratio values across and the thickness (calcification rate) of diurnal bands that are developed in individual shells grown under different synthetic seawater compositions. Results indicate Orbulina universa modify the chemistry of their calcification fluid far from that of external seawater, but are not able to mitigate changes in external seawater. This most likely achieved through the interactive effects of internal pH manipulation and a carbon concentration mechanism. Our results are likely to have important implications for the interpretation of Mg/Ca, B/Ca and U/Ca as proxies seawater temperatures and carbonate system parameters.

  9. Effect of the social influence on topological properties of user-object bipartite networks

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Guo; Hu, Zhaolong; Guo, Qiang

    2013-11-01

    Social influence plays an important role in analyzing online users' collective behaviors [Salganik et al., Science 311, 854 (2006)]. However, the effect of the social influence from the viewpoint of theoretical model is missing. In this paper, by taking into account the social influence and users' preferences, we develop a theoretical model to analyze the topological properties of user-object bipartite networks, including the degree distribution, average nearest neighbor degree and the bipartite clustering coefficient, as well as topological properties of the original user-object networks and their unipartite projections. According to the users' preferences and the global ranking effect, we analyze the theoretical results for two benchmark data sets, Amazon and Bookcrossing, which are approximately consistent with the empirical results. This work suggests that this model is feasible to analyze topological properties of bipartite networks in terms of the social influence and the users' preferences.

  10. Mechanical properties of mineralized collagen fibrils as influenced by demineralization

    PubMed Central

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

    2009-01-01

    Dentin and bone derive their mechanical properties from a complex arrangement of collagen type I fibrils reinforced with nanocrystaline 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. PMID:18467127

  11. 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.

  12. Influence of deuterium implantation on bubble garnet properties

    SciTech Connect

    Gerard, P.; Capra, T.; Magnin, J.

    1985-12-15

    A classical (Y Sm Lu Ca)/sub 3/ (Fe Ge)/sub 5/ O/sub 12/ bubble garnet, supporting 1.8-..mu..m bubbles, has been implanted with 1.5 x 10/sup 16/ D/sup +//sub 2/ cm/sup 2/ at 60 keV either directly or through a predeposited 100-A-thick silica layer. Nuclear techniques such as D (/sup 3/He, ..cap alpha..) p nuclear reaction and Rutherford backscattering combined with channeling measurements were used to determine the implant and damage profiles, respectively. Double-crystal x-ray diffraction was used to measure the maximum strain and magnetic properties were obtained from ferromagnetic resonance. The evolution of these parameters has been studied as a function of annealing treatments. It follows that, as compared to hydrogen, deuterium also interacts at damage-level inducing within the garnet new magnetic phenomena. A higher annealing temperature is required for bubble memory applications. The silica overlayer which is useful for increasing the anisotropy field change, somewhat affects the magnetic properties of the implanted layer.

  13. Influence of snow properties on dense avalanche friction parameters

    NASA Astrophysics Data System (ADS)

    Mohamed, Naaim

    2013-04-01

    The values of the Voellmy friction parameters of 735 historical avalanches that occurred along 26 paths in the Chamonix valley since 1958 are back-analysed with a depth-averaged hydraulic model including sub models for erosion, entrainment and deposition. For each path, the longitudinal and crosswise topographic profiles were derived from a high resolution digital elevation model acquired by laser scanning. The initial snow depth and snow cohesion, as well as various physical properties of snow, were computed from numerical simulations of the detailed snowpack model Crocus fed by the SAFRAN meteorological analysis. For each event, the full ranges of the two friction parameters were scanned and the pairs of friction parameters for which the run-out altitude is found close enough to the observed one (with an uncertainty of 5m), were retained. Statistical class analysis was used to investigate the correlation between the obtained friction coefficients and the snow physical properties. Concerning the inertial friction coefficient, no evident trend with the snow parameters was found. For the static friction coefficient, an increasing trend with the temperature and the density was observed, as well as a decreasing trend with the liquid water content and the initial snow depth.

  14. 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.

  15. Influence of grape pomace extract incorporation on chitosan films properties.

    PubMed

    Ferreira, Andreia S; Nunes, Cláudia; Castro, Alichandra; Ferreira, Paula; Coimbra, Manuel A

    2014-11-26

    Chitosan has been studied as a renewable polymer to form edible films allowing the incorporation of functional compounds. The aim of this work was to evaluate the effects in the chitosan films properties of the incorporation of grape pomace extracts: 0.15% of hot water extract (mainly polysaccharides), 0.15 and 0.3% of chloroform extract (wax), and 0.3 and 0.75% of n-hexane extract (oil). The evaluation of the surface morphology revealed that the films with the aqueous extract had the most homogeneous and smoother topography. The incorporation of higher proportion of wax and oil led to changes in mechanical properties of the films, namely lower resistance and stiffness. The chitosan-based films with 0.75% oil demonstrated a 75% decrease of solubility in water, due to their hydrophobicity, as confirmed by the contact angle and surface free energy measurements. The hydrophobic films showed higher antioxidant capacity in organic medium (ABTS and DPPH assays) whereas the most hydrophilic films showed an improvement in FRAP and reducing power assays. Therefore, all the chitosan-based films prepared by incorporation of these grape pomace extracts are promising for food shelf life extension.

  16. 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

  17. Properties that influence the specific surface areas of carbon nanotubes and nanofibers.

    PubMed

    Birch, M Eileen; Ruda-Eberenz, Toni A; Chai, Ming; Andrews, Ronnee; Hatfield, Randal L

    2013-11-01

    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.

  18. Influence of river discharge and ocean currents on coastal optical properties

    NASA Astrophysics Data System (ADS)

    Cherukuru, Nagur; Brando, Vittorio E.; Schroeder, Thomas; Clementson, Lesley A.; Dekker, Arnold G.

    2014-08-01

    The variability in the optical properties of a coastal region influenced by river runoff and multiple ocean currents in a southern hemisphere setting has been studied. The study area, Tasmanian coastal waters, is influenced by subtropical currents such as the East Australian Current (EAC) and the Zeehan Current (ZC) mix with cooler sub-Antarctic water (SAW). Freshwater discharges from rivers around the island and their mixing with the ocean currents also influence Tasmanian coastal waters. This study was performed to understand the influence of hydrodynamic processes on coastal optical properties and underwater light propagation. Physical, biogeochemical and optical properties were measured in Tasmanian coastal water during the austral autumn of 2007. In this study we found that physical properties have a good correlation with optical properties indicating the role played by hydrodynamic processes in distribution of optically active substances, optical properties of the water mass and underwater light propagation. Analysis of in situ salinity and temperature confirmed the presence of relatively cooler ZC in the South-West region, a cooler mixture of the ZC and SAW in the South-East, warm and saline EAC waters along the East coast and relatively cooler and fresh Bass straight waters along the North coast. In Tasmanian coastal waters light absorption in the water column is controlled by Coloured Dissolved Organic Matter (CDOM) with regionally varying contributions from Non-Algal Particulate (NAP) matter and phytoplankton. Absorption due to CDOM and NAP show a conservative mixing behaviour indicating that these biogeochemical components were delivered by the river and diluted in the coastal water. Suspended particulate matter in Tasmanian coastal water are highly scattering in nature and the beam attenuation is mainly due to light scattering. Variability in probability of light backscattering was mainly due to varying availability of non-algal particulate matter in

  19. Influence of mechanical activation of steel powder on its properties

    NASA Astrophysics Data System (ADS)

    Vaulina, O. Yu; Darenskaia, E. A.; Myachin, Y. V.; Vasilyeva, I. E.; Kulkov, S. N.

    2017-02-01

    It has been studied properties of stainless steel based powders after mechanical activation using planetary ball milling technique. It have been shown that after one minute mechanical activation porosity of sintered steel is less than 5%, which is less than the porosity of the sintered steel powder without mechanical activation. The sample without activation has austenite state, which changes after activation toaustenite and ferrite mixtures. X-ray analysis confirmed that the mechanical activation leads to a change in the phase state of the samples: the samples without activation of the FCC structure (γ-Fe), after activation - FCC (γ-Fe) and BCC (α-Fe). The hardness increases at increasing activation time from 800 MPa for the sample without mechanical activation to 1250 MPa for the sample with the activation time of 10 minutes.

  20. Influence of oxidized starch on the properties of thermoplastic starch.

    PubMed

    Zhang, Yu-Rong; Wang, Xiu-Li; Zhao, Guo-Ming; Wang, Yu-Zhong

    2013-07-01

    Thermoplastic starch was prepared by adding oxidized starches and glycerol together into starch. The addition of oxidized starch improved the rheological properties and also increased the toughness of thermoplastic starch. Compared with TPS30, the elongation at break increased from 126.8% to 152.5% when 5wt% OS 117% was added. Good compatibility of thermoplastic starch between the matrix and oxidized starch was confirmed by SEM. The addition of oxidized starch lowered the storage modulus and glass transition temperature (Tg) of thermoplastic starch, decreasing Tg from 34.1 to 30°C when 10 wt% OS117% was added. The thermal stability of blending was improved by adding oxidized starches, i.e. when 5 wt% OS70% was added, T5% increased from 134 to 156°C. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Microfiller influence on structure and properties of the composite

    NASA Astrophysics Data System (ADS)

    Grishaeva, Natalia; Ljukshin, Boris; Panin, Sergey; Bochkareva, Svetlana

    2015-10-01

    It is demonstrated that the introduction of the particulate microfiller Al2O3 micron size (50 μm) to about 20% by weight affects the mechanical friction and improves the wear resistance properties of the ultra-high molecular weight polyethylene polyethylene (UHMWPE). Experimental studies of coatings based on the UHMWPE filled materials showed that the degree of crystallinity of such materials in increasing the proportion of filler is reduced as compared to the pure UHMWPE, wherein the modulus of elasticity and strength increases. Theoretical analysis of the deformation process of the filled UHMWPE is carried out using the finite element method in conjunction with the procedure consecutive cases. The comparative analysis is performed for the experimental data calculated in the flat setting to enter the correction factor.

  2. Nanoscale defect architectures and their influence on material properties

    NASA Astrophysics Data System (ADS)

    Campbell, Branton

    2006-10-01

    Diffraction studies of long-range order often permit one to unambiguously determine the atomic structure of a crystalline material. Many interesting material properties, however, are dominated by nanoscale crystal defects that can't be characterized in this way. Fortunately, advances in x-ray detector technology, synchrotron x-ray source brightness, and computational power make it possible to apply new methods to old problems. Our research group uses multi-megapixel x-ray cameras to map out large contiguous volumes of reciprocal space, which can then be visually explored using graphics engines originally developed by the video-game industry. Here, I will highlight a few recent examples that include high-temperature superconductors, colossal magnetoresistors and piezoelectric materials.

  3. 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.

  4. Elastic properties of polyunsaturated phosphatidylethanolamines influence rhodopsin function.

    PubMed

    Teague, Walter E; Soubias, Olivier; Petrache, Horia; Fuller, Nola; Hines, Kirk G; Rand, R Peter; Gawrisch, Klaus

    2013-01-01

    Membranes with a high content of polyunsaturated phosphatidylethanolamines (PE) facilitate formation of metarhodopsin-II (M(II)), the photointermediate of bovine rhodopsin that activates the G protein transducin. We determined whether M(II)-formation is quantitatively linked to the elastic properties of PEs. Curvature elasticity of monolayers of the polyunsaturated lipids 18 : 0-22 : 6(n - 3)PE, 18 : 0-22 : 5(n)- 6PE and the model lipid 18 : 1(n - 9)-18 : 1,(n- 9)PE were investigated in the inverse hexagonal phase. All three lipids form lipid monolayers with rather low spontaneous radii of curvature of 26-28 angstroms. In membranes, all three PEs generate high negative curvature elastic stress that shifts the equilibrium of MI(I)/M(II) photointermediates of rhodopsin towards M(II) formation.

  5. Influence of Oxidation on Electrical Properties of Compacted Cu Nanopowders

    NASA Astrophysics Data System (ADS)

    Nadutov, Volodymyr; Perekos, Anatoliy; Kokorin, Volodymyr; Konoplyuk, Sergiy; Kabantsev, Taras

    2016-10-01

    The phase composition and electrical transport properties of Cu powder obtained by electric spark dispersion and the pellets manufactured from this powder were studied by X-ray phase analysis and electric resistance measurements. The compacted powders were annealed in pure Ar atmosphere. It was shown that electrical resistance of the compacted Cu specimens essentially depends on the annealing temperature. In particular, the electrical resistance of the pellet after annealing at 873 K decreases on heating at low temperatures (semiconducting mechanism). As the temperature is increased, semiconducting behavior of resistivity is altered for metallic one. This change of conductivity type is ascribed to formation of metallic oxide and modification of its content during annealing.

  6. Influence of Oxidation on Electrical Properties of Compacted Cu Nanopowders.

    PubMed

    Nadutov, Volodymyr; Perekos, Anatoliy; Kokorin, Volodymyr; Konoplyuk, Sergiy; Kabantsev, Taras

    2016-12-01

    The phase composition and electrical transport properties of Cu powder obtained by electric spark dispersion and the pellets manufactured from this powder were studied by X-ray phase analysis and electric resistance measurements. The compacted powders were annealed in pure Ar atmosphere. It was shown that electrical resistance of the compacted Cu specimens essentially depends on the annealing temperature. In particular, the electrical resistance of the pellet after annealing at 873 K decreases on heating at low temperatures (semiconducting mechanism). As the temperature is increased, semiconducting behavior of resistivity is altered for metallic one. This change of conductivity type is ascribed to formation of metallic oxide and modification of its content during annealing.

  7. 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.

  8. 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.

  9. The influence of different modified graphene on property of DSSCs

    NASA Astrophysics Data System (ADS)

    Xu, Kai; Shen, Yue; Zhang, Zongkun; Cao, Meng; Gu, Feng; Wang, Linjun

    2016-01-01

    Two kinds of modified reduced graphene oxide (rGO) power with different hydrophilic property were synthesized in NH3/hydrazine hydrate (N-rGO) and KOH/hydrazine hydrate (K-rGO) reduction systems, respectively, and be used as counter electrode materials. The as-prepared rGO counter electrodes were confirmed as substitution for Pt counter electrode in dye-sensitized solar cells (DSSCs). The efficiency (η) of DSSCs based on N-rGO counter electrodes achieved 4.72% while that of K-rGO counter electrode was just 3.38%. The electrochemical impedance spectroscopy (EIS) measurements revealed that the hydrophilic K-rGO counter electrode has a low charge transfer resistance (Rct) and the hydrophobic N-rGO counter electrode has a low series resistance (Rs).

  10. Serum Fetuin-A Levels Are Associated with Vascular Calcifications and Predict Cardiovascular Events in Renal Transplant Recipients

    PubMed Central

    Maréchal, Céline; Schlieper, Georg; Nguyen, Pauline; Krüger, Thilo; Coche, Emmanuel; Robert, Annie; Floege, Jorgen; Goffin, Eric; Jadoul, Michel

    2011-01-01

    Summary Background and objectives Vascular calcifications predict cardiovascular disease, the major cause of death in renal transplant recipients (RTRs). We studied the determinants of fetuin-A, a potent circulating calcification inhibitor encoded by the AHSG gene, and tested its association with vascular calcifications and long-term survival and cardiovascular events (CVEs) in RTRs. Design, setting, participants, & measurements Two hundred seventy-seven prevalent RTRs from a single center were included. CVEs and deaths were prospectively recorded during a 5-year follow-up. Results Independent determinants of lower serum fetuin-A levels were lower plasma cholesterol, the AHSG rs4918 G allele, and history of smoking. Low serum fetuin-A level was a determinant of aortic calcifications (assessed using spiral CT). Low fetuin-A levels (≤0.47 g/L, first quintile) were independently associated with CVEs and deaths (hazard ratio = 1.83; 95% confidence interval, 1.07 to 3.04). The association was confirmed for all-cause mortality, and the major adverse cardiovascular endpoints were analyzed separately. Patients with low fetuin-A and high high-sensitivity C-reactive protein (>4.36 mg/L, fourth quintile) levels had a 3.5-fold increased risk of all-cause mortality and CVEs. In the presence of inflammation, CVE-free survival was influenced by common variants in the AHSG gene. Conclusions These data show that low fetuin-A levels are independently associated with aortic calcifications and a higher risk of CVEs and mortality. They support fetuin-A as a circulating biomarker able to identify RTRs at risk for vascular calcifications and CVEs. PMID:21527649

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

    NASA Astrophysics Data System (ADS)

    Kwiatkowski, L.

    2016-02-01

    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 21st Century. In laboratory manipulations, calcifying organisms have exhibited reduced calcification under elevated pCO2 conditions. Consequently, in situ observations of the sensitivity of calcifying communities to natural saturation state variability are increasingly valued as they incorporate complex species interactions, and capture the carbonate chemistry conditions to which communities are acclimatized. Using intensive seawater sampling techniques we assess the community level sensitivity of calcification rates to natural temporal 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 limited 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

  12. 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).

  13. 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

  14. 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.

  15. Role of Vitamin D in Uremic Vascular Calcification

    PubMed Central

    Zheng, Jing-Quan

    2017-01-01

    The risk of cardiovascular death is 10 times higher in patients with CKD (chronic kidney disease) than in those without CKD. Vascular calcification, common in patients with CKD, is a predictor of cardiovascular mortality. Vitamin D deficiency, another complication of CKD, is associated with vascular calcification in patients with CKD. GFR decline, proteinuria, tubulointerstitial injury, and the therapeutic dose of active form vitamin D aggravate vitamin D deficiency and reduce its pleiotropic effect on the cardiovascular system. Vitamin D supplement for CKD patients provides a protective role in vascular calcification on the endothelium by (1) renin-angiotensin-aldosterone system inactivation, (2) alleviating insulin resistance, (3) reduction of cholesterol and inhibition of foam cell and cholesterol efflux in macrophages, and (4) modulating vascular regeneration. For the arterial calcification, vitamin D supplement provides adjunctive role in regressing proteinuria, reverse renal osteodystrophy, and restoring calcification inhibitors. Recently, adventitial progenitor cell has been linked to be involved in the vascular calcification. Vitamin D may provide a role in modulating adventitial progenitor cells. In summary, vitamin D supplement may provide an ancillary role for ameliorating uremic vascular calcification. PMID:28286758

  16. Malnutrition, a new inducer for arterial calcification in hemodialysis patients?

    PubMed

    Zhang, Kun; Cheng, Gang; Cai, Xue; Chen, Jie; Jiang, Ying; Wang, Tong; Wang, Jingfeng; Huang, Hui

    2013-03-18

    Arterial calcification is a significant cardiovascular risk factor in hemodialysis patients. A series of factors are involved in the process of arterial calcification; however, the relationship between malnutrition and arterial calcification is still unclear. 68 hemodialysis patients were enrolled in this study. Nutrition status was evaluated using modified quantitative subjective global assessment (MQSGA). Related serum biochemical parameters were measured. And the radial artery samples were collected during the arteriovenous fistula surgeries. Hematoxylin/eosin stain was used to observe the arterial structures while Alizarin red stain to observe calcified depositions and classify calcified degree. The expressions of bone morphogenetic protein 2 (BMP2) and matrix Gla protein (MGP) were detected by immunohistochemistry and western blot methods. 66.18% hemodialysis patients were malnutrition. In hemodialysis patients, the calcified depositions were mainly located in the medial layer of the radial arteries and the expressions of BMP2 and MGP were both increased in the calcified areas. The levels of serum albumin were negatively associated with calcification score and the expressions of BMP2 and MGP. While MQSGA score, serum phosphorus and calcium × phosphorus product showed positive relationships with calcification score and the expressions of BMP2 and MGP. Malnutrition is prevalent in hemodialysis patients and is associated with arterial calcification and the expressions of BMP2 and MGP in calcified radial arteries. Malnutrition may be a new inducer candidate for arterial calcification in hemodialysis patients.

  17. Malnutrition, a new inducer for arterial calcification in hemodialysis patients?

    PubMed Central

    2013-01-01

    Background Arterial calcification is a significant cardiovascular risk factor in hemodialysis patients. A series of factors are involved in the process of arterial calcification; however, the relationship between malnutrition and arterial calcification is still unclear. Methods 68 hemodialysis patients were enrolled in this study. Nutrition status was evaluated using modified quantitative subjective global assessment (MQSGA). Related serum biochemical parameters were measured. And the radial artery samples were collected during the arteriovenous fistula surgeries. Hematoxylin/eosin stain was used to observe the arterial structures while Alizarin red stain to observe calcified depositions and classify calcified degree. The expressions of bone morphogenetic protein 2 (BMP2) and matrix Gla protein (MGP) were detected by immunohistochemistry and western blot methods. Results 66.18% hemodialysis patients were malnutrition. In hemodialysis patients, the calcified depositions were mainly located in the medial layer of the radial arteries and the expressions of BMP2 and MGP were both increased in the calcified areas. The levels of serum albumin were negatively associated with calcification score and the expressions of BMP2 and MGP. While MQSGA score, serum phosphorus and calcium × phosphorus product showed positive relationships with calcification score and the expressions of BMP2 and MGP. Conclusions Malnutrition is prevalent in hemodialysis patients and is associated with arterial calcification and the expressions of BMP2 and MGP in calcified radial arteries. Malnutrition may be a new inducer candidate for arterial calcification in hemodialysis patients. PMID:23506394

  18. Intracranial physiological calcifications evaluated with cone beam CT

    PubMed Central

    Sedghizadeh, P P; Nguyen, M; Enciso, R

    2012-01-01

    Objectives The purpose of this study was to evaluate cone beam CT (CBCT) scans for the presence of physiological and pathological intracranial calcifications. Methods CBCT scans from male and female patients that met our ascertainment criteria were evaluated retrospectively (n = 500) for the presence of either physiological or pathological intracranial calcifications. Results Out of the 500 patients evaluated, 176 had evidence of intracranial physiological calcification (35.2% prevalence), and none had evidence of pathological calcification. There was a 3:2 male-to-female ratio and no ethnic predilection; the ages of affected patients ranged from 13 years to 82 years with a mean age of 52 years. The majority of calcifications appeared in the pineal/habenular region (80%), with some also appearing in the choroid plexus region bilaterally (12%), and a smaller subset appearing in the petroclinoid ligament region bilaterally (8%). Conclusions Intracranial physiological calcifications can be a common finding on CBCT scans, whereas pathological intracranial calcifications are rare. PMID:22842632

  19. Tissue age affects calcification in the scleractinian coral Madracis mirabilis.

    PubMed

    Elahi, Robin; Edmunds, Peter J

    2007-02-01

    In this study, two factorial experiments were used to investigate the role of tissue age in affecting the phenotypic expression of calcification in scleractinian corals. Both experiments tested whether calcification was altered by tissue age and whether corals of different ages exploit plasticity to differing degrees by altering calcification rates under new environmental conditions. To isolate age and size effects, branches of the Caribbean coral Madracis mirabilis were broken into a distal portion that was functionally young and a proximal portion that was functionally old. Fragments were transplanted from a deep (17 m) to a shallow (9 m) site in a Jamaican lagoon to test whether age affected the plasticity of calcification. Both experiments demonstrated that calcification scaled isometrically in the two age groups, and although scaling exponents were indistinguishable statistically among ages, young fragments calcified faster than old fragments. Thus, the effect of age on calcification rate was absolute and independent of size. However, the interactive effect of age and depth was not significant, demonstrating that ability to alter calcification rate (i.e., the extent of phenotypic plasticity for this trait) was unaffected by age. Together, these patterns are consistent with the hypothesis that the proximal modules (i.e., polyps) of M. mirabilis are subject to physiological senescence, as has been reported for other clonal organisms, including algae, fungi, plants, bryozoans, ascidians, and other cnidarians.

  20. Targeting vascular calcification: softening-up a hard target.

    PubMed

    Kapustin, Alexander; Shanahan, Catherine M

    2009-04-01

    Widespread vascular calcification is a ubiquitous feature of aging and is prevalent in association with a number of common pathologies including atherosclerosis, renal failure, and diabetes. Once thought of as innocuous, emerging evidence suggests that calcification is causal in precipitating vascular events and mediating chronic cardiovascular damage, independent of disease context. Importantly, a large body of data has shed light on the factors that favor the formation of calcification in vivo, as well as on the complex mechanisms that initiate and promote it. This has identified some novel targets and allowed for the possibility that calcification can potentially be blocked and ultimately regressed. Targets include local and circulating inhibitors of calcification as well as factors that may ameliorate vascular smooth muscle cell (VSMC) apoptosis. Despite this, the vasculature remains a difficult tissue to target and currently there are no effective treatments in general use. More crucially, any potential treatments will need to be carefully evaluated as they may impinge on bone metabolism. Our best hope for the near future is to normalize factors associated with accelerated calcification in pathologies such as renal failure where, aberrant mineral metabolism, as well as treatment regimes, may contribute to the initiation and progression of calcification.

  1. Skeletal maturity assessment using mandibular canine calcification stages.

    PubMed

    Džemidžić, Vildana; Tiro, Alisa; Zukanović, Amila; Redžić, Ismeta; Nakaš, Enita

    2016-11-01

    The aims of this study were: to investigate the relationship between mandibular canine calcification stages and skeletal maturity; and to evaluate whether the mandibular canine calcification stages may be used as a reliable diagnostic tool for skeletal maturity assessment. This study included 151 subjects: 81 females and 70 males, with ages ranging from 9 to 16 years (mean age: 12.29±1.86 years). The inclusion criteria for subjects were as follows: age between 9 and 16 years; good general health without any hormonal, nutritional, growth or dental development problems. Subjects who were undergoing or had previously received orthodontic treatment were not included in this study. The calcification stages of the left permanent mandibular canine were assessed according to the method of Demirjian, on panoramic radiographs. Assessment of skeletal maturity was carried out using the cervical vertebral maturation index (CVMI), as proposed by the Hassel-Farman method, on lateral cephalograms. The correlation between the calcification stages of mandibular canine and skeletal maturity was estimated separately for male and female subjects. Correlation coefficients between calcification stages of mandibular canine and skeletal maturity were 0.895 for male and 0.701 for female subjects. A significant correlation was found between the calcification stages of the mandibular canine and skeletal maturity. The calcification stages of the mandibular canine show a satisfactory diagnostic performance only for assessment of pre-pubertal growth phase. Copyright © 2016 by Academy of Sciences and Arts of Bosnia and Herzegovina.

  2. Recent advances in research on human aortic valve calcification.

    PubMed

    Furukawa, Ken-Ichi

    2014-01-01

    Aortic valve calcification can aggravate aortic stenoses, and it is a significant cause of sudden cardiac death. The increasing number of patients with age-related calcification is a problem in developed nations. However, the only treatment option currently available is highly invasive cardiac valve replacement. Therefore, clarification of the etiology of calcification is urgently needed to develop drug therapies and prevention methods. Recent studies have revealed that calcification is not a simple sedimentation of a mineral through a physicochemical phenomenon; various factors dynamically contribute to the mechanism. Further, we are finally beginning to understand the cellular origins of calcification, which had been unclear for a long time. Based on these findings that help to clarify potential drug targets, we expect to establish drug therapies that reduce the stress on patients. In this paper, I introduce the latest findings on cells that are most likely to contribute to calcification and on calcification-related factors that may lead to the development of drug therapies.

  3. 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.

  4. Inverse hardness distribution and its influence on mechanical properties

    SciTech Connect

    Liscic, B.; Grubisic, V.; Totton, G.E.

    1996-12-31

    Studying the pattern of hardness distribution on round bars cross-section after quenching, Shimizu and Tamura have introduced the expression of {open_quotes}inverse hardening{close_quotes}. Opposite to normal hardness distribution it shows lower hardness at the surface and higher hardness in the core. This phenomenon takes place dependent on: hardenability of the steel, cross-section size of the workpiece and on quenching condition. It is related to the delayed quenching with discontinuous change of cooling rate, and to the incubation period consumed before changing the cooling rate. Their experiments using cylindrical specimens of 50 mm Dia, made of the same heat of AISI-4140 steel have shown that polymer solutions (PAG) of high concentration may reproducibly cause delayed quenching and yield inverse hardness distribution. This Controllable Delayed Quenching (CDQ) technology, influencing intentionally the dynamics of heat extraction, has a great potential lo increase the depth of hardening, compared to conventional quenching practice. After tempering a workpiece having inverse hardness distribution to suitable tempering temperature, uniform microstructure of tempered martensite, giving the best impact toughness, can be obtained through the whole cross-section. Bending fatigue tests with adequate specimens have shown a significant increase of the fatigue life for tempered specimens with inverse hardness distribution after quenching, in comparison with specimens having normal hardness distribution.

  5. Association of conjunctival and corneal calcification with vascular calcification among hepatitis-C-seropositive hemodialysis patients.

    PubMed

    AbouSeif, Khaled; Sany, Dawlat; Elshahawy, Yasser; Seddik, Ayman; Rahman, Khedr; Gaber, Moustapha

    2016-01-01

    Disorders associated with the hepatitis C virus (HCV) have been reported including cardiovascular, metabolic, and central nervous system diseases. Since chronic HCV infections may be curable, their identification as causal contributors to cardiovascular risk could offer new perspectives in the prevention of cardiovascular disease. The aim of this study is to investigate the association between HCV and aortic arch calcification (AAC) and corneal and conjunctival calcification (CCC) in maintenance hemodialysis (MHD) patients; further, we assessed the correlation of CCC with vascular calcification. A total of 100 patients undergoing hemodialysis (HD) in our hospital were included in this study. Patients underwent a complete ocular examination including intraocular pressure, and CCC was looked for by slit lamp and fundoscopy. CCC was graded according to modified Porter and Crombie classification system described by Tokuyama et al. Helical computerized tomographic chest examination was used to evaluate the grading of AAC. Demographic, hematological, biochemical, and dialysis-related data were obtained. There was significant difference between seropositive (n = 51) and seronegative patients (n = 49) regarding grading of AAC and CCC (P <0.001). Significant positive correlation was found between grading of CCC, AAC, age (P <0.001), duration on HD (P <0.001), HCV-antibody positivity (P <0.001), serum calcium level (P <0.001), serum phosphorus level (P <0.001), calcium × phosphorus product (P <0.001), and i-parathormone level (P < 0.001). In addition, CCC grading positively correlated with AAC. Our results suggest that patients undergoing HD infected with the HCV have high degree of CCC, AAC, and mineral metabolism disorder. The strong correlation between CCC and AAC indicates that CCC evaluation is an easy, fast, non-invasive method, and might be used as an indirect indicator to detect vascular calcification in patients undergoing MHD.

  6. Oral calcium supplements do not affect the progression of aortic valve calcification or coronary artery calcification.

    PubMed

    Bhakta, Mayurkumar; Bruce, Charles; Messika-Zeitoun, David; Bielak, Lawrence; Sheedy, Patrick F; Peyser, Patricia; Sarano, Maurice

    2009-01-01

    The use of oral calcium supplementation among the elderly for prevention and treatment of osteoporosis and osteopenia is increasing. The incidence of aortic valve disease and coronary artery disease also is increasing. No study thus far has been done to demonstrate whether this affects the progression of calcification in both the valves and vasculature. We sought to determine whether ingestion of oral calcium supplementation has an effect on aortic valve calcification (AVC) and coronary artery calcification (CAC). We performed an independent assessment of AVC, CAC, and calcium supplementation among patients enrolled in the Epidemiology of Coronary Artery Calcification study who were >60 years of age and had baseline and 4-year follow-up AVC data. In this population-based study of Olmsted County (Minnesota) residents, AVC and CAC scores were determined prospectively by electron beam computed tomography. We evaluated baseline demographic data and analyzed whether those patients using calcium supplementation had a higher rate of progression of both AVC and CAC. We identified 257 patients (mean age, 67.8+/-5.2 years), 144 of whom were women. Twenty-five patients (all women) reported using calcium supplements. Analysis of the 144 women (25 taking calcium supplementation) showed there was no difference in the progression of AVC (mean difference in baseline and follow-up AVC score; no supplement versus supplement, 30+/-9 vs 39+/-28; P=.73) or CAC (mean difference in baseline and follow-up CAC score; no supplement vs supplement, 47+/-15 vs 112+/-22; P=.154). There were no significant differences between the 2 groups with regard to baseline AVC, serum calcium, renal function, diabetes, hypertension, cholesterol, or body mass index. In this community-based observational study with a 4-year follow-up, no significant increased progression of AVC or CAC was found in women taking oral calcium supplementation. Larger prospective, randomized studies are needed to confirm these

  7. Effects of dialdehyde starch on calcification of collagen matrix.

    PubMed

    Liu, Yi; Acharya, Gayathri; Lee, Chi H

    2011-12-01

    Dialdehyde starch (DAS), a polymeric aldehyde derived from naturally occurring polysaccharide, was used as an additive to the collagen (COL) matrix in an effort to improve its physical and biological properties. The effects of DAS on the thermal stability of COL were characterized by differential scanning calorimetry. The conformational changes in COL were characterized by resistance to protease degradation assay, residual amine analysis, and Fourier-transform infrared spectroscopy. To assess biocompatibility enhancement, the calcium content in porcine aortic valve interstitial cells (PAVICs) on exposure to cardiovascular stents coated with DAS-stabilized COL was examined using atomic absorption spectroscopy. Thermal stability of DAS-stabilized COL was affected by DAS in a concentration dependent manner, reaching maximum at the saturation concentration (DAS:COL = 1:120) and decreasing the thermal stability at the concentrations above saturation. In the long-term exposure condition (21 days), stents coated with DAS at the lowest concentration significantly reduced the calcification rate of PAVIC, when compared with bare stent (p = 0.001). DAS appears to be an efficient additive to the COL matrix in improving its physical and biological properties. Further optimization process is needed for the suitable crosslinking conditions of DAS, which subsequently enhances thermal strength and anticalcification activities of COL matrix. Copyright © 2011 Wiley Periodicals, Inc.

  8. 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.

  9. Viscoelastic properties of actin networks influence material transport

    NASA Astrophysics Data System (ADS)

    Stam, Samantha; Weirich, Kimberly; Gardel, Margaret

    2015-03-01

    Directed flows of cytoplasmic material are important in a variety of biological processes including assembly of a mitotic spindle, retraction of the cell rear during migration, and asymmetric cell division. Networks of cytoskeletal polymers and molecular motors are known to be involved in these events, but how the network mechanical properties are tuned to perform such functions is not understood. Here, we construct networks of either semiflexible actin filaments or rigid bundles with varying connectivity. We find that solutions of rigid rods, where unimpeded sliding of filaments may enhance transport in comparison to unmoving tracks, are the fastest at transporting network components. Entangled solutions of semiflexible actin filaments also transport material, but the entanglements provide resistance. Increasing the elasticity of the actin networks with crosslinking proteins slows network deformation further. However, the length scale of correlated transport in these networks is increased. Our results reveal how the rigidity and connectivity of biopolymers allows material transport to occur over time and length scales required for physiological processes. This work was supported by the U. Chicago MRSEC

  10. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Influences of aquifer properties on flow dimensions in dolomites.

    PubMed

    Verbovsek, Timotej

    2009-01-01

    The paper focuses on analyses and correlations of flow dimensions in different dolomite aquifers in Slovenia. Flow dimensions are obtained through the reinterpretation of 72 pumping tests with the generalized radial flow model, based on the fractional flow dimension. The average value of flow dimensions is 2.16 for all dolomites. A study of flow dimensions in individual aquifers categorized according to their lithological properties shows that higher dimensions occur in massive late-diagenetic Cordevolian and Anisian dolomites compared with bedded Main, Baca, and especially Lower Triassic dolomites, which contain a greater proportion of noncarbonate minerals. Partially penetrating wells have higher flow dimensions than fully penetrating wells. Flow dimensions are poorly correlated with hydraulic conductivities of fractures. When comparing the quantities of major dissolved minerals, obtained by hydrogeochemical inverse modeling, with the values of flow dimensions, the Cordevolian and Anisian dolomites are found to exhibit the highest values of both dissolved dolomite and flow dimensions, indicating that greater dissolution occurs at higher flow dimensions. For other aquifers, data points are more scattered and the correlation is mostly poor. When compared with three-dimensional fractal dimensions of fracture networks, there is no correlation with flow dimensions. However, almost all the values of flow dimensions are lower than the corresponding fractal dimensions in dolomites (average D= 2.77), possibly indicating the channeling of flow within the available space of the fracture networks, consequently reducing the flow dimensions.

  12. Determinants of aortic bioprosthetic valve calcification assessed by multidetector CT.

    PubMed

    Mahjoub, Haïfa; Mathieu, Patrick; Larose, Eric; Dahou, Abdelaziz; Sénéchal, Mario; Dumesnil, Jean-Gaston; Després, Jean-Pierre; Pibarot, Philippe

    2015-03-01

    Cusp calcification is the main mechanism leading to bioprosthetic heart valve (BPV) failure. Recent studies suggest that BPV calcification is an active rather than passive process probably modulated by several mechanisms including lipid-mediated inflammation and dysfunctional phosphocalcic metabolism. To identify the clinical and metabolic determinants of BPV calcification assessed by multidetector CT (MDCT). Presence of BPV calcification was assessed by MDCT in 194 patients who had undergone aortic valve replacement. A calcification score was individually calculated and expressed in mm(3). Patients also underwent a clinical evaluation, a Doppler echocardiographic exam, and a plasma lipid and phosphocalcic profile. 46 patients (24%) had BPV calcification (cusp calcification score >0 mm(3)). After adjustment for age, gender, and time interval since BPV implantation, increased calcium-phosphorus product (OR 1.11, 95% CI 1.01 to 1.23 per 1 unit; p=0.02) and the presence of prosthesis-patient mismatch (OR 3.67, 95% CI 1.25 to 10.6; p=0.01) were the strongest independent factors associated with BPV calcification. Calcium supplement intake, age and female gender were independently associated with increased calcium-phosphorus product. This study suggests that higher calcium-phosphorus product and prosthesis-patient mismatch promote BPV calcification. Furthermore, this study reports that calcium supplements, which are extensively prescribed in elderly patients, are independently associated with higher calcium-phosphorus product. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  13. Management of rotator cuff calcific tendinosis guided by ultrasound elastography.

    PubMed

    Lin, Yen-Huai; Chiou, Hong-Jen; Wang, Hsin-Kai; Lai, Yi-Chen; Chou, Yi-Hong; Chang, Cheng-Yen

    2015-10-01

    Ultrasound (US) elastography can provide information about the hardness of calcification and might help decide treatment strategy. The purpose of this study was to evaluate the hardness of the calcific area within rotator cuffs by US elastography as an aid for the selection of aspiration or fine-needle repeated puncture for the treatment of rotator cuff calcific tendinosis. This prospective study included 39 patients (32 males, 7 females; mean age, 52.9 years) who received US elastography and gray-scale ultrasonography before US-guided treatment for rotator cuff calcific tendinosis. The morphology of the calcifications was classified as arc, fragmented, nodular, and cystic types. US elastography using virtual touch imaging (acoustic radiation force impulse) technique was performed to examine the calcified region to obtain an elastogram that was graded dark, intermediate, or bright. The hardness of the calcifications were recorded, and graded as hard, sand-like, or fluid-like tactile patterns during the US-guided treatment, and the tactile patterns were compared with the results of US elastography and gray-scale ultrasonography. Though the morphologies of the calcifications were significantly related to the tactile pattern of the needle punctures (p < 0.001), gray-scale US could not accurately demonstrate the hardness of the calcifications. With the aid of elastography, the fluid-like tactile pattern could be predicted well as a nondark pattern by elastography (p < 0.001). Ultrasound elastography is a useful modality for evaluation of rotator cuff calcific tendinosis, and as an aid to guide management. If elastography shows the calcified area as a non-dark pattern, then fine-needle aspiration should be performed. Copyright © 2015. Published by Elsevier Taiwan.

  14. [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.

  15. 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.

  16. 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

  17. 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.

  18. Orbital melanoma with calcification: A diagnostic dilemma

    PubMed Central

    Bains, Sukhdeep; Kim, Usha; Shanti, R

    2016-01-01

    Primary orbital melanoma is rare and has varied initial presentation. A 28-year-old female presented with proptosis and decreased vision in the left eye. Computed tomography scan showed an orbital mass with contrast enhancement and calcification around the optic nerve leading to a diagnosis of meningioma. The patient chose to be on observation. Loss of vision with an increase in proptosis was seen at 6 months follow-up. On surgical exploration, a well-defined pigmented mass was seen encasing the optic nerve. Histopathological analysis revealed a malignant melanoma. Metastatic workup was negative. Left eye lid sparing exenteration was done. A high index of suspicion is necessary in a rapidly growing suspected optic nerve sheath meningioma and a differential diagnosis including orbital melanoma be considered. PMID:28112137

  19. 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.

  20. Basic mechanisms of calcific aortic valve disease.

    PubMed

    Mathieu, Patrick; Boulanger, Marie-Chloé

    2014-09-01

    Calcific aortic valve disease (CAVD) is the most common heart valve disorder. There is no medical treatment to prevent and/or promote the regression of CAVD. Hence, it is of foremost importance to delineate and understand the key basic underlying mechanisms involved in CAVD. In the past decade our comprehension of the underpinning processes leading to CAVD has expanded at a fast pace. Hence, our understanding of the basic pathobiological processes implicated in CAVD might lead eventually to the development of novel pharmaceutical therapies for CAVD. In this review, we discuss molecular processes that are implicated in fibrosis and mineralization of the aortic valve. Specifically, we address the role of lipid retention, inflammation, phosphate signalling and osteogenic transition in the development of CAVD. Interplays between these different processes and the key regulation pathways are discussed along with their clinical relevance.

  1. [Molecular mechanism of idiopathic basal ganglia calcification].

    PubMed

    Wang, Cheng; Xu, Xuan; Li, Lulu; Wang, Tao; Zhang, Min; Shen, Lu; Tang, Beisha; Liu, Jingyu

    2015-08-01

    Idiopathic basal ganglia calcification (IBGC), also known as Fahr’s disease, is an inheritable neurodegenerative syndrome characterized by mineral deposits in the basal ganglia and other brain regions. Patients with IBGC are often accompanied with movement disorders, cognitive impairment as well as psychiatric abnormalities. So far, no therapeutic drug has been developed for the treatment of IBGC. Recently, genetic studies have identified several genes associated with IBGC, including SLC20A2, PDGFRB, PDGFB, ISG15 and XPR1. Loss-of-function mutations in these genes have been associated with disturbance in phosphate homeostasis in brain regions, the dysfunction of blood-brain barrier as well as enhanced IFN-α/β immunity. In this review, we summarize the latest research progress in the studies on molecular genetics of IBGC, and discuss the molecular mechanisms underlying the pathophysiology of mutations of different genes.

  2. An unusual case of extensive peritoneal calcification: A case report

    PubMed Central

    Roriz, Diogo; Abreu, Inês; Costa, João F.; Soares, Pedro Belo; Caseiro-Alves, Filipe

    2014-01-01

    The peritoneum is the largest serous membrane of the body and can be exposed to several injuries that may cause abnormal findings on imaging exams. Linear peritoneal calcification is remarkably rare, usually secondary to long duration peritoneal dialysis. We report an uncommon case of extensive peritoneal calcification in a 39-year-old female without long exposure to peritoneal dialysis solutions, in which peritoneal calcification could be linked to Alport syndrome and previous adverse reaction to intraperitoneal iodinated contrast. Radiologist should be aware of this and related imaging findings, know when to search for them as well as understand their clinical value. PMID:26937431

  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. 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.

  5. Cerebroretinal microangiopathy with calcifications and cysts

    PubMed Central

    Xu, Wenrui; Zhao, Jiuliang; Zhu, Yicheng; Zhang, Weihong

    2017-01-01

    Abstract Rational: Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is believed to be an autosomal recessive genetic disease, with disorders in multisystem organs. Its characteristic neurological disorders manifested on neuroimaging are a triad of leukoencephalopathy, intracranial calcifications, and parenchymal cysts. In this paper, we report a CRMCC patient with multisystem involvement, focusing on the neuroimaging features, to get a better understanding of the rare disease and improve our diagnostic ability. Patient Concerns: The 23-year-old female patient firstly presented with an adolescence onset of ophthalmological manifestations. Four years later, hematological and neurological disorders occurred, the latter of which demonstrated a relatively slow progression in the following 7 years preceding her presentation to our hospital. Interventions: During hospitalization, disorders involving digestive, cardiovascular and respiratory systems were also detected. In addition, a more comprehensive depiction of neurological disorders on neuroimaging was also obtained. Diagnoses: On the basis of multiple system disorders and the detection of mutations in conserved telomere maintenance component 1(CTC1) gene, a diagnosis of CRMCC was made. Outcomes: After supportive therapy during her 4-week hospitalization, the patient's general condition improved and was released from the hospital. Lessons: CRMCC could be primarily diagnosed with the aid of its multiple system disorders and remarkable neuroimaging features. Cerebral micro hemorrhages determined by the combination of CT and T2∗-weighted magnetic resonance images in our case could provide some additional information for diagnosis. Furthermore, several other associated disorders were depicted for the first time in our case, expanding the clinical spectrum of CRMCC. PMID:28072696

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

    PubMed

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

    2016-09-28

    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.

  7. 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

  8. 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

  9. Magnesium prevents β-glycerophosphate-induced calcification in rat aortic vascular smooth muscle cells.

    PubMed

    Bai, Yaling; Zhang, Junxia; Xu, Jinsheng; Cui, Liwen; Zhang, Huiran; Zhang, Shenglei; Feng, Xunwei

    2015-07-01

    Vascular calcification (VC), in which high serum phosphate plays a critical role, is one major problem in patients with chronic kidney disease. Clinical studies report that magnesium has a protective effect on VC. However, the studies regarding the impact of high serum magnesium on VC at a cellular level are few and require further investigation. Therefore, the present study explored the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in rat aortic vascular smooth muscle cells (RAVSMCs). In the present study, the addition of magnesium decreased calcium deposition, which was increased by BGP. Higher magnesium levels inhibited BGP-induced alkaline phosphatase (ALP) activity and decreased the expression of core-binding factor α-1 (Cbfα1). In conclusion, higher magnesium levels prevented BGP-induced calcification in RAVSMCs and inhibited the expression of Cbfα1 and ALP. Thus, magnesium is influencing the expression of Cbfα1 and ALP associated with VC and may have the potential to serve as a role for VC in clinical situations.

  10. 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.

  11. Magnesium prevents β-glycerophosphate-induced calcification in rat aortic vascular smooth muscle cells

    PubMed Central

    BAI, YALING; ZHANG, JUNXIA; XU, JINSHENG; CUI, LIWEN; ZHANG, HUIRAN; ZHANG, SHENGLEI; FENG, XUNWEI

    2015-01-01

    Vascular calcification (VC), in which high serum phosphate plays a critical role, is one major problem in patients with chronic kidney disease. Clinical studies report that magnesium has a protective effect on VC. However, the studies regarding the impact of high serum magnesium on VC at a cellular level are few and require further investigation. Therefore, the present study explored the effect of magnesium on calcification induced by β-glycerophosphate (BGP) in rat aortic vascular smooth muscle cells (RAVSMCs). In the present study, the addition of magnesium decreased calcium deposition, which was increased by BGP. Higher magnesium levels inhibited BGP-induced alkaline phosphatase (ALP) activity and decreased the expression of core-binding factor α-1 (Cbfα1). In conclusion, higher magnesium levels prevented BGP-induced calcification in RAVSMCs and inhibited the expression of Cbfα1 and ALP. Thus, magnesium is influencing the expression of Cbfα1 and ALP associated with VC and may have the potential to serve as a role for VC in clinical situations. PMID:26171172

  12. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Calcification capacity of porous pHEMA-TiO₂ composite hydrogels.

    PubMed

    Li, Chao; Zheng, Yu-Feng; Lou, Xia

    2009-11-01

    Many investigations have been attempted to promote calcification of synthetic polymers for applications as orthopaedic and dental implants. In this study, novel titanium dioxide (TiO(2)) reinforced porous poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels were synthesized. Calcification capacity of the composite polymers was examined using light microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy after incubation of the materials in a simulated body fluid up to 53 days. Mechanical strength, porosity and in vitro cytotoxicity were also investigated. Calcification capacity of porous pHEMA was significantly enhanced by the addition of TiO(2) particulates. Infiltration of calcium phosphate, up to 1000 mum, was observed. The diffusion capacity of calcium ions was affected by the porosity and the interconnectivity of pores in the hydrogel polymers which were influenced by the presence of TiO(2) and the monomer concentration. Cell viability tests indicated that porous hydrogels containing 7.5% TiO(2) were not toxic to 3T3 fibroblast cells. These results demonstrate that incorporating TiO(2) nanoparticulates can promote enhanced formation of calcium phosphate whilst maintaining the porosity and interconnectivity of the hydrogel polymers and would be very useful for the development of orthopaedic tissue engineering scaffolds.

  14. The influence of nanopore dimensions on the electrochemical properties of nanopore arrays studied by impedance spectroscopy.

    PubMed

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

    2014-11-11

    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.

  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. Transcatheter aortic valve implantation with the direct flow medical prosthesis: Impact of native aortic valve calcification degree on outcomes.

    PubMed

    D'Ancona, Giuseppe; Agma, Hüseyin U; Ince, Hüseyin; El-Achkar, Gihan; Dißmann, Martin; Ortak, Jasmin; Kische, Stephan

    2017-01-01

    We present our single center experience with the direct flow medical (DFM) prosthesis addressing the impact of native aortic valve (AV) calcification degree on outcomes. The DFM® has been introduced for transcatheter aortic valve implantation (TAVI). The valve has a nonmetallic and inflatable support structure. Patients were divided in two groups according to preoperative cardiac computed tomography (CT): group I moderate calcification and group II heavy calcification of the total AV area. We evaluated 118 patients: 53 (45%) group I and 65 (55%) group II. Preoperative trans-AV gradient and calcification extension across the aortic unit were significantly higher in group II (P = 0.008 and P < 0.0001). CT perimeter derived annular diameter (group I 24.7 ± 2.1 mm vs. group II 24.8 ± 1.9; P = 0.6) and implanted prosthesis size (group I 26.1 ± 1.5 mm vs. group II 25.7 ± 1.5; P = 0.1) were similar. Hemodynamics were similar: mean gradient 16.1 ± 5.9 mm Hg (group I) vs. 17.3 ± 6.5 mm Hg (group II) (P = 0.3). Total aortic regurgitation (AR) was mild in 5.7% in group I and 20% in group II (P = 0.03). None developed moderate/severe AR. Heavy AV calcification was the sole independent determinant for mild regurgitation (P = 0.02; OR = 7; 95% CI: 1.2-37.6). Follow-up (289 days; 40-760 days) estimated survival was 88.1% (group I) and 93.8% (group II) (P = 0.3). Independent of AV calcification degree, adequate sizing and implantation can be achieved with the DFM®. Although higher burden of calcification increases the rate of mild AR, no patient developed moderate and severe AR. Short-term estimated survival was not influenced by calcification degree. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Calcein labelling and electrophysiology: insights on coral tissue permeability and calcification

    PubMed Central

    Tambutté, Eric; Tambutté, Sylvie; Segonds, Natacha; Zoccola, Didier; Venn, Alexander; Erez, Jonathan; Allemand, Denis

    2012-01-01

    The mechanisms behind the transfer of molecules from the surrounding sea water to the site of coral calcification are not well understood, but are critical for understanding how coral reefs are formed. We conducted experiments with the fluorescent dye calcein, which binds to calcium and is incorporated into growing calcium carbonate crystals, to determine the permeability properties of coral cells and tissues to this molecule, and to determine how it is incorporated into the coral skeleton. We also compared rates of calcein incorporation with rates of calcification measured by the alkalinity anomaly technique. Finally, by an electrophysiological approach, we investigated the electrical resistance of coral tissues in order to better understand the role of tissues in ionic permeability. Our results show that (i) calcein passes through coral tissues by a paracellular pathway, (ii) intercellular junctions control and restrict the diffusion of molecules, (iii) intercellular junctions should have pores of a size higher than 13 Å and lower than 20 nm, and (iv) the resistance of the tissues owing to paracellular junctions has a value of 477 ± 21 Ohm cm2. We discuss the implication of our results for the transport of calcium involved in the calcification process. PMID:21613296

  19. Calcein labelling and electrophysiology: insights on coral tissue permeability and calcification.

    PubMed

    Tambutté, Eric; Tambutté, Sylvie; Segonds, Natacha; Zoccola, Didier; Venn, Alexander; Erez, Jonathan; Allemand, Denis

    2012-01-07

    The mechanisms behind the transfer of molecules from the surrounding sea water to the site of coral calcification are not well understood, but are critical for understanding how coral reefs are formed. We conducted experiments with the fluorescent dye calcein, which binds to calcium and is incorporated into growing calcium carbonate crystals, to determine the permeability properties of coral cells and tissues to this molecule, and to determine how it is incorporated into the coral skeleton. We also compared rates of calcein incorporation with rates of calcification measured by the alkalinity anomaly technique. Finally, by an electrophysiological approach, we investigated the electrical resistance of coral tissues in order to better understand the role of tissues in ionic permeability. Our results show that (i) calcein passes through coral tissues by a paracellular pathway, (ii) intercellular junctions control and restrict the diffusion of molecules, (iii) intercellular junctions should have pores of a size higher than 13 Å and lower than 20 nm, and (iv) the resistance of the tissues owing to paracellular junctions has a value of 477 ± 21 Ohm cm(2). We discuss the implication of our results for the transport of calcium involved in the calcification process.

  20. 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

  1. Vitamin D Affects Survival Independently of Vascular Calcification in Chronic Kidney Disease

    PubMed Central

    Barreto, Daniela Veit; Barreto, Fellype Carvalho; Liabeuf, Sophie; Temmar, Mohammed; Boitte, Francis; Choukroun, Gabriel; Fournier, Albert; Massy, Ziad A.

    2009-01-01

    Background and objectives: Cardiovascular disease is the main cause of mortality in chronic kidney disease (CKD) patients. Vitamin D might have beneficial effects on vascular health. The aim of this study was to determine the prevalence of vitamin D deficiency (25-hydroxyvitamin D [25D] ≤ 15 ng/ml) and insufficiency (25D levels between 16 and 30 ng/ml) in a cohort of patients at different CKD stages and the relationships between vitamin D serum levels, vascular calcification and stiffness, and the mortality risk. Design, setting, participants & measurements: One hundred forty CKD patients (85 men, mean age 67 ± 12 yr; CKD stages 2 [8%], 3 [26%], 4 [26%], 5 [7%], and 5D [(33%]) were allocated for a prospective study. Serum levels of 25D and 1,25-dihydroxyvitamin D, aortic calcification score, and pulse wave velocity (PWV) were evaluated. Results: There was a high prevalence of vitamin D deficiency (42%) and insufficiency (34%). Patients with 25D ≤ 16.7 ng/ml (median) had a significantly lower survival rate than patients with 25D >16.7 ng/ml (mean follow-up, 605 ± 217 d; range, 10 to 889; P = 0.05). Multivariate adjustments (included age, gender, diabetes, arterial pressure, CKD stage, phosphate, albumin, hemoglobin, aortic calcification score and PWV) confirmed 25D level as an independent predictor of all-cause mortality. Conclusions: Vitamin D deficiency and insufficiency were highly prevalent in this CKD cohort. Low 25D levels affected mortality independently of vascular calcification and stiffness, suggesting that 25D may influence survival in CKD patients via additional pathways that need to be further explored. PMID:19443628

  2. Are occupational repetitive movements of the upper arm associated with rotator cuff calcific tendinopathies?

    PubMed

    Sansone, Valerio C; Meroni, Roberto; Boria, Paola; Pisani, Salvatore; Maiorano, Emanuele

    2015-02-01

    Calcifying tendinopathy (CT) of the shoulder is a common painful disorder, although the etiology and pathogenesis remain largely unknown. Recent theories about the role of excessive mechanical load in the genesis of CT have been proposed. Driven by the interest for these new theories, we investigated the hypothesis of a relationship between work-related repetitive movements of the upper arm, considered a potential cause of shoulder overload, and the presence of shoulder CT. A secondary aim was to obtain data on CT prevalence in a female sample from the working-age general population, as little data currently exist. 199 supermarket cashiers and 304 female volunteers recruited from the general population underwent a high-resolution ultrasonography of the rotator cuffs of both shoulders, and the presence of tendinopathies, with or without calcification, was recorded. The prevalence of calcific tendinopathy was 22.6 % in the cashiers group and 24.4 % in the control group. There were no statistically significant differences in the prevalence of calcifications between the two groups (p = 0.585), either for the dominant shoulder [OR = 0.841 (95 % CI 0.534-1.326)] or for the non-dominant shoulder [OR = 0.988 (95 % CI 0.582-1.326)]. We observed bilateral calcifications in 8.5 % of cashiers, and 9.6 % of controls, and an increase in prevalence of CT with age in both groups. Work-related repetitive movements of the upper arm did not induce a higher prevalence of shoulder CT compared with the female sample from the general population. If CT etiopathogenesis is related to mechanical load, CT onset may be influenced not only by loading history, but also by individual factors. Level of evidence Prognosis study, Level II.

  3. 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.

  4. Association of Serum Phosphate and Related Factors in ESRD-Related Vascular Calcification

    PubMed Central

    Zheng, Cai-Mei; Lu, Kuo-Cheng; Wu, Chia-Chao; Hsu, Yung-Ho; Lin, Yuh-Feng

    2011-01-01

    Vascular calcification is common in ESRD patients and is important in increasing mortality from cardiovascular complications in these patients. Hyperphosphatemia related to chronic kidney disease is increasingly known as major stimulus for vascular calcification. Hyperphosphatemia and vascular calcification become popular discussion among nephrologist environment more than five decades, and many researches have been evolved. Risk factors for calcification are nowadays focused for the therapeutic prevention of vascular calcification with the hope of reducing cardiovascular complications. PMID:21660259

  5. Influence of excess diamine on properties of PMR polyimide resins and composites

    NASA Technical Reports Server (NTRS)

    Hurwitz, F. I.

    1980-01-01

    By varying the stoichiometry of the reactants in the preparation of PMR polyimide resin, changes occur in molecular weight distribution which influence the rheological properties and thus the processability of the resin, as well as the mechanical properties of the composite. The influence of 1-10 percent molar excess MDA on the molecular weight distribution and rheological properties of an imidized PMR system were exposed. Molecular weight distribution is characterized by gel permeation chromatography of the imidized molding compound; shear viscosity is related to changes in average molecular weight. The thermo-oxidative stability at 600 F, glass transition temperature, flexural and interlaminar shear properties of PMR polyimide/Celion 6000 graphite fiber composites are compared as a function of the percent excess MDA in the monomer reactant mixture.

  6. Influence of surface reconstruction on dopant incorporation and transport properties of GaAs(Bi) alloys

    NASA Astrophysics Data System (ADS)

    Field, R. L.; Occena, J.; Jen, T.; Del Gaudio, D.; Yarlagadda, B.; Kurdak, C.; Goldman, R. S.

    2016-12-01

    We report on the influence of surface reconstruction on silicon dopant incorporation and transport properties during molecular-beam epitaxy of GaAs(Bi) alloys. GaAs(Bi) growth with an (n × 3) reconstruction leads to n-type conductivity, while growth with a (2 × 1) reconstruction leads to p-type conductivity. We hypothesize that the presence or absence of surface arsenic dimers prevents or enables dopant incorporation into arsenic lattice sites. We consider the influence of bismuth anions on arsenic-dimer mediated dopant incorporation and the resulting electronic transport properties, demonstrating the applicability of this mechanism to mixed anion semiconductor alloys.

  7. The Influence of Polymer Solution on the Properties of Electrospun 3D Nanostructures

    NASA Astrophysics Data System (ADS)

    Amariei, N.; Manea, L. R.; Bertea, A. P.; Bertea, A.; Popa, A.

    2017-06-01

    The remarkable versatility of electrospinning is the result of the fact that many factors influence the process results. The characteristics of the electrospun nanofibres depend crucially, besides technological parameters, on the nature of the polymer solution. In the present article it is overviewed the way the properties of the polymer solution, such as concentration, viscosity, conductivity, surface tension, volatility characteristics of the used solvent, influence the main features of the obtained nanofibres.

  8. Influence of emulsifying agents on the properties of cellulose acetate butyrate and ethylcellulose microcapsules.

    PubMed

    Kristmundsdóttir, T; Ingvarsdóttir, K

    1994-01-01

    Microcapsules of ibuprofen were prepared according to the solvent evaporation method, using two coating polymers, cellulose acetate butyrate and ethylcellulose. The influence of two emulsifying agents, polysorbat 80 and polyvinyl alcohol, on the properties of the microcapsules was investigated. The results show that type and concentration of emulsifying agent influences size distribution, drug loading and amount of free drug on the surface of the microcapsules.

  9. Influence of the structural properties on the pseudocritical magnetic behavior of single-wall ferromagnetic nanotubes

    NASA Astrophysics Data System (ADS)

    Salazar-Enríquez, C. D.; Restrepo-Parra, E.; Restrepo, J.

    2012-04-01

    In this work we address the influence of the crystalline structure, concretely when the system under study is formed by square or hexagonal unit cells, upon the magnetic properties and pseudocritical behavior of single-wall ferromagnetic nanotubes. We focus not only on the effect of the geometrical shape of the unit cell but also on their dimensions. The model employed is based on the Monte Carlo method, the Metropolis dynamics and a nearest neighbors classical Heisenberg Hamiltonian. Magnetization per magnetic site, magnetic susceptibility, specific heat and magnetic energy were computed. These properties were computed varying the system size, unit cell dimension and temperature. The dependence of the nearest neighbor exchange integral on the nanotubes geometrical characteristics is also discussed. Results revealed a strong influence of the system topology on the magnetic properties caused by the difference in the coordination number between square and hexagonal unit cell. Moreover, the nanotubes diameter influence on magnetic properties is only observed at very low values, when the distance between atoms is less than it, presented by the 2D sheet. On the other hand, it was concluded that the surface-related finite-size effects do not influence the magnetic nanotubes properties, contrary to the case of other nano-systems as thin films and nanoparticles among others.

  10. 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.

  11. The influence of compound admixtures on the properties of high-content slag cement

    SciTech Connect

    Dongxu, L.; Xuequan, W.; Jinlin, S.; Yujiang, W.

    2000-01-01

    Based on the activation theory of alkali and sulfate, the influence of compound admixtures on the properties of high-content slag cement was studied by testing the strength, pore structure, hydrates, and microstructure, Test results show that compound admixtures can obviously improve the properties of high-content slag cement. The emphasis of the present research is two-fold: substituting gypsum with anhydrite and calcining gypsum. These both can improve early and later performance.

  12. Influence of nonmartensitic transformation products on mechanical properties of tempered martensite

    NASA Technical Reports Server (NTRS)

    Hodge, J M; Lankford, W T

    1952-01-01

    The influence of nonmartensitic transformations products on the mechanical properties of tempered martensite is presented for samples of a SAE 4340 steel, partially isothermally transformed to specific high-temperature transformation products and quenched and tempered to hardness values of from 25 to 40 Rockwell c. The effects of upper bainite in amounts of 1,5, 10, 20 and 50 percent, of 5 percent ferrite, and of 5 percent pearlite on the tensile, impact, and fatigue properties are evaluated. (author)

  13. 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- ...

  14. [The hemodynamic characterization of the diabetic patient with arterial calcifications].

    PubMed

    Vega Gómez, M E; Ley Pozo, J; Aldama Figueroa, A; Lima Santana, B; Montalvo Diago, J; Bustillo, C; Fernández Boloña, A; Gutiérrez Jiménez, O; Ramirez Muñoz, O; Martínez Hernández, R

    1993-01-01

    This study was designed to describe the presence of calcifications according to the clinical features of the diabetic patient and the hemodynamics of the calcified arteries. With this purpose, 197 lower limbs from diabetic patients (type I and II) and carbon-hydrate intolerant patients, were studied. In all of the patients, the pressure ratio leg/arm was measured. On the same way, the arterial flow velocity was recorded using the Doppler ultrasonography on the pedia and postero-tibial arteries. The arterial calcifications, evident on the radiography of the foot, were more frequent between the type I patients and the neuro-infections diabetic foot. According to the hemodynamics point of view, we found a trend of association of more pathologic arterial flow velocity curves with the presence of calcifications (specially on the intima layer). It was also remarkable that an arterial incomprensibility was always associated with arterial calcifications.

  15. In vitro computerized evaluation of biological cardiac prosthesis calcification.

    PubMed

    Gatti, A M; Noera, G; Massini, C

    1985-01-01

    The late valvular bioprostheses failure is mainly related to leaflet calcification. This study reports a new approach to testing the biological prostheses calcification applying a computerized technique to x-ray picture. A bovine glutaraldehyde-fixed bioprostheses (BB) was implanted in two sheep in mitral position. The experimental procedure was performed on valves explanted six months after surgery. The BB x-ray pictures were tested by means of a video display computer (VDC) that can process radiographic, photographic or microscopic images and also evaluate the optical density of image quantifiable. The calcification zone assumes different values according to the calcification degree. The VDC can colour the BB x-ray images and display them on monitors (one black and white, one colour) with the colours strictly related to the grey levels of the image.

  16. Acute Calcific Tendinitis of the Rectus Femoris: A Case Series

    PubMed Central

    Kobayashi, Hideo; Kaneko, Haruka; Homma, Yasuhiro; Baba, Tomonori; Kaneko, Kazuo

    2015-01-01

    Introduction: Periarticular calcific tendinitis is a common cause of Orthopedic outpatient referral. Calcific tendinitis of the rectus femoris, however, is very rare and not well known. Due to its rarity, correct diagnosis and prompt treatment are not fully understood. Case Report: Two females (38 and 40 years old) of acute calcific tendinitis of the rectus femoris with the good clinical course without any operative treatment were presented. The pain was managed with oral non-steroidal antiinflammatory drugs and/or local steroid injection. Interval radiographic assessment showed complete resorption of the calcification. Conclusion: Establishing the correct diagnosis and initiating prompt treatment are shown to be important in achieving resolution of symptoms and in avoiding unnecessary investigations. PMID:27299063

  17. Effects of. gamma. irradiation on cartilage matrix calcification

    SciTech Connect

    Nijweide, P.J.; Burger, E.H.; van Delft, J.L.; Kawilarange-de Haas, E.W.M.; Wassenaar, A.M.; Mellink, J.H.

    1980-10-01

    The effect of ..gamma.. irradiation on cartilage matrix calcification was studied in vitro. Metatarsal bones of 14- to 17-day-old embryonic mice were dissected and cultured under various conditions. Prior to culture, half of the metatarsal bones received absorbed doses of 1.0 to 30.0 Gy ..gamma.. radiation. Their paired counterparts served as controls. Irradiation inhibited longitudinal growth and calcification of the cartilage matrix during culture. In addition, a number of histological changes were noted. The inhibition of matrix calcification appeared to be due to an inhibition of the intracellular calcium accumulation. The formation of extracellular calcification foci and the growth of the calcified area already present at the moment of explanation were not inhibited during culture.

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

    SciTech Connect

    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.

  19. Ectopic calcification in lambs from feeding the plant Cestrum diurnum.

    PubMed

    Simpson, C F; Bruss, M L

    1979-01-01

    Hypercalcemia and ectopic calcification were induced in 5 lambs by supplementing the diet with the dried leaves of the plant Cestrum diurnum, for 8 to 9 weeks. Lambs developed mineralization of blood vessels, heart, kidneys, and lungs. These tissues were examined by light and electron microscopy. In the vascular tissue there was calcification of elastic fibers in the hyperplastic intima and the media, along with mineralization of mitochondria of aortic smooth muscle cells. Myocardial cells and their mitochondria were mineralized. In the kidney, there was calcification of the epithelium of the distal convoluted tubules and collecting tubules, Bowman's capsule, and the mesangial cells of the glomeruli. In the lung, there was mineralization of the alveolar septal walls and the bronchi and bronchioles. Feeding of the calcinogenic plant to lambs caused extensive soft tissue calcification. Results of the study indicated that degeneration was the early soft tissue lesion in this plant toxicity.

  20. 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

  1. Calcific periarthritis of the elbow presenting as acute tennis elbow.

    PubMed

    Jawad, F; Jawad, A S M

    2014-01-01

    A 28-year-old woman presented with sudden acute lateral epicondylitis. There was no history of preceding trauma or repetitive use of the arm. Because of the acute onset and signs of acute inflammation, an X-ray was arranged. The X-ray showed a hyperdense calcified elongated globule distal to the lateral epicondyle. A diagnosis of calcific periarthritis (calcium apatite) of the elbow was made. Calcific periarthritis has rarely been reported as a cause of acute elbow pain.

  2. 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

  3. Cardiovascular calcifications in chronic kidney disease: Potential therapeutic implications.

    PubMed

    Bover, Jordi; Ureña-Torres, Pablo; Górriz, José Luis; Lloret, María Jesús; da Silva, Iara; Ruiz-García, César; Chang, Pamela; Rodríguez, Mariano; Ballarín, José

    Cardiovascular (CV) calcification is a highly prevalent condition at all stages of chronic kidney disease (CKD) and is directly associated with increased CV and global morbidity and mortality. In the first part of this review, we have shown that CV calcifications represent an important part of the CKD-MBD complex and are a superior predictor of clinical outcomes in our patients. However, it is also necessary to demonstrate that CV calcification is a modifiable risk factor including the possibility of decreasing (or at least not aggravating) its progression with iatrogenic manoeuvres. Although, strictly speaking, only circumstantial evidence is available, it is known that certain drugs may modify the progression of CV calcifications, even though a direct causal link with improved survival has not been demonstrated. For example, non-calcium-based phosphate binders demonstrated the ability to attenuate the progression of CV calcification compared with the liberal use of calcium-based phosphate binders in several randomised clinical trials. Moreover, although only in experimental conditions, selective activators of the vitamin D receptor seem to have a wider therapeutic margin against CV calcification. Finally, calcimimetics seem to attenuate the progression of CV calcification in dialysis patients. While new therapeutic strategies are being developed (i.e. vitamin K, SNF472, etc.), we suggest that the evaluation of CV calcifications could be a diagnostic tool used by nephrologists to personalise their therapeutic decisions. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  4. A review of the effect of diet on cardiovascular calcification.

    PubMed

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

    2015-04-21

    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.

  5. Gated cardiac tomographic visualization of coronary artery calcification

    SciTech Connect

    Markivee, C.R.; Hoyt, T.S.; Francis, R.A.; Burns, J.; Ruark, B.

    1984-07-01

    Coronary artery calcification (CAC) is usually detected by fluoroscopy or on cine films during coronary angiography, but measurement of the calcification is not possible. Gated tomography of the heart provides a full sized image with high contrast spatial resolution of 0.76 mm. The radiation exposure to the heart is between 1-5% of that experienced with coronary cinefluorography. Measurement of the diameter of calcium deposits is possible and calcium that could be related to arterial stenosis may be identified.

  6. Vascular Calcification: Current Genetics Underlying This Complex Phenomenon

    PubMed Central

    Pérez-Hernández, Nonanzit; Aptilon-Duque, Gad; Blachman-Braun, Ruben; Vargas-Alarcón, Gilberto; Rodríguez-Cortés, Adrián Asael; Azrad-Daniel, Shely; Posadas-Sánchez, Rosalinda; Rodríguez-Pérez, José Manuel

    2017-01-01

    Objective: Vascular calcification is the consequence of the complex interaction between genetic, environmental, and vascular factors, which ultimately lead to the deposition of calcium in the tunica intima (atherosclerotic calcification) or tunica media (Mönckenberg's sclerosis). Vascular calcification is also closely related to other pathologies, such as diabetes mellitus, dyslipidemia, and chronic kidney disease. It has been concluded that the degree of vascular calcification may vary from person to person, even if the associated pathologies and environmental factors are the same. Therefore, this suggests an important genetic contribution to the development of vascular calcification. This review aimed to find the most recent evidence about vascular calcification pathophysiology regarding the genetic aspects and molecular pathways. Data Sources: We conducted an exhaustive search in Scopus, EBSCO, and PubMed with the keywords “genetics and vascular calcification”, “molecular pathways, genetic and vascular calcification” and included the main articles from January 1995 up to August 2016. We focused on the most recent evidence about vascular calcification pathophysiology regarding the genetic aspects and molecular pathways. Study Selection: The most valuable published original and review articles related to our objective were selected. Results: Vascular calcification is a multifactorial disease; thus, its pathophysiology cannot be explained by a single specific factor, rather than by the result of the association of several genetic variants, molecular pathway interactions, and environmental factors that promote its development. Conclusion: Although several molecular aspects of this mechanism have been elucidated, there is still a need for a better understanding of the factors that predispose to this disease. PMID:28469108

  7. 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. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

  8. 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

  9. Acid-base balance in uremic rats with vascular calcification.

    PubMed

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

    2014-01-01

    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. Twenty-two rats with CKD induced by 5/6 nephrectomy (5/6 Nx) and 10 nonuremic control rats were studied. 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. In an experimental model of uremic rats, VC showed high positive correlation with AG and SID.

  10. Dietary potassium regulates vascular calcification and arterial stiffness.

    PubMed

    Sun, Yong; Byon, Chang Hyun; Yang, Youfeng; Bradley, Wayne E; Dell'Italia, Louis J; Sanders, Paul W; Agarwal, Anupam; Wu, Hui; Chen, Yabing

    2017-10-05

    Vascular calcification is a risk factor that predicts adverse cardiovascular complications of several diseases including atherosclerosis. Reduced dietary potassium intake has been linked to cardiovascular diseases such as hypertension and incidental stroke, although the underlying molecular mechanisms remain largely unknown. Using the ApoE-deficient mouse model, we demonstrated for the first time to our knowledge that reduced dietary potassium (0.3%) promoted atherosclerotic vascular calcification and increased aortic stiffness, compared with normal (0.7%) potassium-fed mice. In contrast, increased dietary potassium (2.1%) attenuated vascular calcification and aortic stiffness. Mechanistically, reduction in the potassium concentration to the lower limit of the physiological range increased intracellular calcium, which activated a cAMP response element-binding protein (CREB) signal that subsequently enhanced autophagy and promoted vascular smooth muscle cell (VSMC) calcification. Inhibition of calcium signals and knockdown of either CREB or ATG7, an autophagy regulator, attenuated VSMC calcification induced by low potassium. Consistently, elevated autophagy and CREB signaling were demonstrated in the calcified arteries from low potassium diet-fed mice as well as aortic arteries exposed to low potassium ex vivo. These studies established a potentially novel causative role of dietary potassium intake in regulating atherosclerotic vascular calcification and stiffness, and uncovered mechanisms that offer opportunities to develop therapeutic strategies to control vascular disease.

  11. Dual energy subtraction method for breast calcification imaging

    NASA Astrophysics Data System (ADS)

    Koukou, Vaia; Martini, Niki; Fountos, George; Michail, Christos; Sotiropoulou, Panagiota; Bakas, Athanasios; Kalyvas, Nektarios; Kandarakis, Ioannis; Speller, Robert; Nikiforidis, George

    2017-03-01

    The aim of this work was to present an experimental dual energy (DE) method for the visualization of microcalcifications (μCs). A modified radiographic X-ray tube combined with a high resolution complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) X-ray detector was used. A 40/70 kV spectral combination was filtered with 100 μm cadmium (Cd) and 1000 μm copper (Cu) for the low/high-energy combination. Homogenous and inhomogeneous breast phantoms and two calcification phantoms were constructed with various calcification thicknesses, ranging from 16 to 152 μm . Contrast-to-noise ratio (CNR) was calculated from the DE subtracted images for various entrance surface doses. A calcification thickness of 152 μm was visible, with mean glandular doses (MGD) in the acceptable levels (below 3 mGy). Additional post-processing on the DE images of the inhomogeneous breast phantom resulted in a minimum visible calcification thickness of 93 μm (MGD=1.62 mGy). The proposed DE method could potentially improve calcification visibility in DE breast calcification imaging.

  12. Vascular calcification in chronic kidney disease: a clinical review.

    PubMed

    Eddington, Helen; Sinha, Smeeta; Kalra, Philip A

    2009-03-01

    Vascular calcification, which is associated with arterial stiffness, is now known to be an important predictor of cardiovascular and all-cause mortality in patients with renal disease. This calcification starts developing in the early stages of chronic kidney disease (CKD) and is present in over 50% of patients at the time of dialysis commencement. Once calcification is present it continues to progress, though some medications have been shown to slow this progression. Vascular calcification and bone abnormalities are now both encompassed by the term of CKD-mineral bone disorder and are thought to be part of the same disease process in CKD. Vascular calcification and arterial stiffness have been extensively researched in the renal population and many factors are known to be associated with their presence and progression. This calcification is an important factor to be considered in the management of the renal patient but there are different methods available for its measurement. These details will be discussed further in this review along with evidence available for management of this important complication of renal disease.

  13. 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.

  14. Deep-penetration photoacoustic array imaging of calcifications

    NASA Astrophysics Data System (ADS)

    Hsiao, Tsai-Chu; Cheng, Yao-Yu; Tein, Wan-Ting; Luo, Shih-Bin; Chiou, De-Yi; Chung, Ren-Jei; Li, Meng-Lin

    2013-06-01

    Calcifications are one of the most important indicators for early breast cancer detection. We explore the feasibility of deep-penetration photoacoustic (PA) imaging of calcifications based on a medical ultrasound array imaging platform. Intralipid and chicken breast phantoms embedded with different-sized hydroxyapatite (HA) particles, which are the major components of calcifications, were imaged to verify the equipment's capability and penetration depth for the visualization of calcifications. An optimal near-infrared excitation wavelength was selected to maximize PA signals of HAs, resulting in a better HA signal-to-blood ratio. We demonstrated that PA imaging is capable of visualizing 0.5-mm HA particles at a depth of 3 cm in chicken breast phantoms. The noise-equivalent penetration depth of the system for visualizing 0.5-mm HA particles in the human breast was estimated to be about 2.9 to 3.5 cm, which is clinically relevant as calcifications are usually found at a depth of 0.6 to 3.0 cm. Moreover, the feasibility of differentiating HA from blood by the PA spectroscopic technique was presented and the mechanism of the HA signal generation was discussed. The results show that PA imaging is a promising technique for real-time visualization of breast calcifications.

  15. Characterization of Dystrophic Calcification Induced in Mice by Cardiotoxin

    PubMed Central

    Zhao, Yongdong; Urganus, Annette L.; Spevak, Lyudmila; Shrestha, Sheela; Doty, Stephen B.; Boskey, Adele L.

    2010-01-01

    Dystrophic calcifications often occur after injury, infection, or onset of certain rheumatic diseases. Treatment has been limited to surgical removal following failure of medical therapy. In an attempt to establish a reproducible animal model for dystrophic calcification that permitted the screening of potential interventions, we evaluated cardiotoxin (injury)-induced calcifications in three murine strains at both the cellular and ultrastructural levels. All osteopontin null mice and tumor necrosis factor receptor null mice on a C57B6 background had calcifications at days 3 and 7 after injury compared to 75% of wild-type C57B6 mice. There was no difference in mineral content among calcifications from the three mouse strains. Osteogenesis was suggested by the expression of osteocalcin, osterix, and alkaline phosphatase in calcified murine muscle tissue. Osteoclast-like cells facilitated the removal of transient dystrophic deposits (<28 days) in all models. However, none of the models showed an association of mineral crystals with collagen, suggesting that the deposits were not bone-like. The dystrophic mechanism was validated as cell death, and mitochondrial calcifications occurred soon after skeletal muscle injury in the three murine strains. PMID:19690791

  16. Effectiveness of Anti-Calcification Technologies in a Rabbit Model.

    PubMed

    Wright, Greg; de la Fuente, Angela

    2015-05-01

    A kinetic profile revealing calcification progression is a powerful method for assessing the anti-calcification efficacy of various tissue treatments compared to the traditional analysis of a single time point in studies with rabbits. Tissue calcification was compared between test and control discs in rabbits. Test groups received either ThermaFix-processed bovine pericardium, or porcine leaflets processed with Linx, or alpha-amino oleic acid (AOA). Control groups received glutaraldehyde-treated porcine valve leaflets, and bovine pericardium. Tissue discs were implanted intramuscularly in rabbits and explanted every five days until day 75. Levels of calcium and phosphorus were then monitored in the rabbit tissues. Calcium concentrations were plotted over time, with a sigmoidal curve being used for each kinetic profile. The ThermaFix group exhibited a lower calcium plateau level compared to the bovine control (107 ± 24 versus 258 ± 120 μg Ca2+ per mg dry tissue, respectively), while the Linx group exhibited a lower calcium plateau compared to porcine controls (130 ± 34 μg versus 280 ± 80 μg Ca2+ per mg dry tissue, respectively). The AOA group showed a low level of calcification through 40 days, but this was subsequently increased to a plateau of 258 ± 135 μg Ca2+ per mg dry tissue. The study results showed that effects on the rate and level of calcification of anti-calcification technologies can be modulated. In particular, time is important when assessing tissue technology effectiveness.

  17. 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.

  18. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  20. Analysis of the influence of the mode type on microstrip antenna directive properties

    NASA Astrophysics Data System (ADS)

    Bem, Daniel J.; Katulski, Ryszard J.

    The subject of this paper is the analysis of the mode type influence on the directive properties of a microstrip antenna with a rectangular radiating element. Investigations in this field were carried out using the aperture model of the antenna. The results of numerical investigations are presented.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  2. Influence of formulation and preparation process on ambroxol hydrochloride dry powder inhalation characteristics and aerosolization properties.

    PubMed

    Ren, Yachao; Yu, Chaoqun; Meng, Kangkang; Tang, Xing

    2008-09-01

    The objective of this study is to evaluate the influence of formulation and preparation process on ambroxol hydrochloride (AH) dry powder inhalation (DPI) characteristics and aerosolization properties. Spray-dried samples of AH, AH/leucine, and AH/leucine/mannitol were prepared from their corresponding water solutions under the same conditions to study the influence of the composition, and the AH/leucine/mannitol (2.5/0.5/1 by weight) formulation was used for investigation of the effect of the preparation process. Following spray-drying, the resulting powders were characterized using scanning electron microscopy, laser diffraction, tapped density, and angle of repose measurements, and the aerosolization performance was determined using a twin-stage liquid impinger. AH/leucine/mannitol (2.5/0.5/1 by weight) obtained by cospray-drying improved the AH aerosolization properties. The AH/leucine/mannitol (2.5/0.5/1 by weight) preparation exhibited the following properties: 62.34% yield, 0.34 g/cm(3) tap density, 2.71 microm d(ae), 33.45 degrees angle of repose, and 30.93% respirable fraction. The influence of the preparation process on DPI characteristics and aerosolization properties was relatively small, but the influence of the composition was relatively large. Optimization of DPI can be achieved by selecting the most appropriate formulation and preparation process.

  3. Evaluating the influence of residual stresses on the magnetic properties of electrical steel

    SciTech Connect

    Korzunin, G.S.; Chistyakov, V.K.

    1995-04-01

    The method described for evaluating the influence of residual stresses on the magnetic properties of coiled cold-rolled electrical steel con